Title of Invention	A WASHING MACHINE
Abstract	The present invention proposes a washing machine whose driving mechanism is constructed without the band-brake mechanism for the purpose of simplifying the structure, where the wash-and-extraction tub is rotated in a direction opposite to the rotation of the -agitator for improving the washing or rinsing performance. In an embodiment of the invention, a sun gear 38 is fixed to a driving shaft 33 driven by the power of a motor. An internal gear 39 is fixed to the inner circumference of a case 32 constituting a part of an outer shaft rotating with the wash-and-extraction tub. A planetary gears 40 is disposed engaging with the above two gears, and the shafts 41 of the planetary gears 40 is connected to an inner shaft 6 rotating with the agitator. A clutch mechanism is constructed so that the connection and disconnection between the driving shaft 33 and the outer shaft is switched by inserting or pulling claws 434 of a movable body 43 rotating with the case 32 and slidable in the vertical direction into or out of engaging holes 184 of a large pulley 18. During the washing or rinsing process, the driving shaft 33 is disconnected from the case, where the case 32 receives a reaction force due to the rotation of the planetary gears 40 and rotates in the direction opposite to the rotation of the inner shaft 6.

Title of Invention

A WASHING MACHINE

Abstract

The present invention proposes a washing machine whose driving mechanism is constructed without the band-brake mechanism for the purpose of simplifying the structure, where the wash-and-extraction tub is rotated in a direction opposite to the rotation of the -agitator for improving the washing or rinsing performance. In an embodiment of the invention, a sun gear 38 is fixed to a driving shaft 33 driven by the power of a motor. An internal gear 39 is fixed to the inner circumference of a case 32 constituting a part of an outer shaft rotating with the wash-and-extraction tub. A planetary gears 40 is disposed engaging with the above two gears, and the shafts 41 of the planetary gears 40 is connected to an inner shaft 6 rotating with the agitator. A clutch mechanism is constructed so that the connection and disconnection between the driving shaft 33 and the outer shaft is switched by inserting or pulling claws 434 of a movable body 43 rotating with the case 32 and slidable in the vertical direction into or out of engaging holes 184 of a large pulley 18. During the washing or rinsing process, the driving shaft 33 is disconnected from the case, where the case 32 receives a reaction force due to the rotation of the planetary gears 40 and rotates in the direction opposite to the rotation of the inner shaft 6.

Full Text	The present invention relates to a washing machine and, more precisely, to an automatic washing machine provided with a wash-and-extraction tub placed rotatably in an outer tub and an agitator placed rotatably on the inner bottom of the wash-and-extraction tub. BACKGROUND OF THE INVENTION In a conventional and general type of automatic washing machine, during the course of washing and rinsing process, only the agitator placed on the inner bottom of the wash-and-extraction tub is driven to rotate back and forth at low speed, while, during the course of the extraction process, both the wash-and-extraction tub and the agitator are driven to rotate together unidirectionally at high speed. In order to switch the driving, many of conventional washing machines are provided with a clutch mechanism such as using a spring clutch in a driving mechanism. In such a clutch mechanism, the spring clutch is fastened solely in one direction so that the driving shaft is connected to a supporting shaft of the wash-and-extraction tub. Therefore, when the driving shaft is stopped during the high-speed rotation, the driving shaft is disconnected from the supporting shaft, and the wash-and-extraction tub continues rotating by inertia. For this reason, the driving system is provided with a band-brake mechanism in order to stop the wash-and-extraction tub immediately after the extraction process ends, or at other timings. The brake mechanism also has a function to prevent the wash-and-extraction tub from rotating together with the agitator during the course of washing or rinsing process. However, the above-described clutch mechanism or band-brake mechanism is so complicated in structure that it has become one major reason for an increase in the production cost of a washing machine. Therefore, especially in a relatively inexpensive washing machine with simplified functions, there has been a great demand for omitting the band-brake mechanism as well as providing a driving system with a simplified structure of a clutch mechanism. As described above, the wash-and-extraction tub is generally stationary during washing or rinsing process. A washing machine has already been known, however, whose washing or rinsing performance is improved by rotating the wash-and-extraction tub actively at low speed in the direction opposite to the rotation of the agitator. In such a type of washing machine, the rotary driving power of the driving shaft is transmitted to the supporting shaft of the wash-and-extraction tub and to the shaft of the agitator via respective reduction mechanisms. As a result, the driving system has become more complicated than that of conventional washing machines, and impractical due to the cost. That is, the attempt to improve the washing or rinsing performance by the above-described method conflicts absolutely with the above-mentioned demand for simplifying the driving system of a washing machine. The present invention is achieved in this respect placing its main object to simplify the structure of the driving system of a washing machine, and to provide a washing machine with an improved washing or rinsing performance. SUMMARY OF THE INVENTION The washing machine according to the present invention achieved to solve the above-described problems includes a wash-and-extraction tub rotatably provided in an outer tub and an agitator rotatably provided on the inner bottom of the wash-and-extraction tub, and is characterized by further including: a) a hollow outer shaft rotating with the wash-and-extraction tub, b) an inner shaft inserted in the outer shaft and rotating with the agitator, c) a driving shaft provided coaxially with the outer shaft and inner shaft, and driven to rotate by a motor, d) reduction means including: an internal gear formed with or connected to the outer shaft, a sun gear formed with or connected to the driving shaft, and planetary gears connected to the inner shaft and engaging and rotating with the intemal gear and the sun gear, and e) driving switch means for connecting or disconnecting the driving shaft and the outer shaft, wherein, during the washing or rinsing process, the driving shaft is disconnected from the outer shaft by the driving switch means while the driving shaft and the outer shaft are connected via the sun gear, planetary gears and internal gear, so that the agitator is rotated in a preset direction, and, with the rotation of the agitator, the wash-and-extraction tub is rotated in a direction opposite to the preset direction by a reaction force of the planetary gears working on the internal gear. In the washing machine of the present invention, the outer shaft is disconnected from the driving shaft during the washing or rinsing process, and the outer shaft is not forcefully halted by a brake mechanism or the like, which is different from a conventional washing machine. This means that a brake mechanism for braking the outer shaft is not provided, or not used even if it is provided. At this time, the outer shaft is connected to the driving shaft via the internal gear, planetary gears and sun gear, and, as the driving shaft rotates, the outer shaft receives a load, or a reaction force, from the planetary gears in the direction opposite to the rotary direction. There, the outer shaft rotates in the opposite direction to the inner shaft due to the reaction force. Thus, the wash-and-extraction tub is rotated in the opposite direction to the agitator. Therefore, as the wash-and-extraction tub rotates in the direction opposite to the moving direction of the laundry on the water current generated by the rotation of the agitator, the friction between the laundry and the wash-and-extraction tub increases and the washing and rinsing performance is improved. The thus-rotating wash-and-extraction tub generates water current opposite to that generated by the agitator, so that a turbulent flow is generated and vertical water current can be obtained with ease. As a result, the laundry changes its position up and down on the vertical water current, so that the washing or rinsing is performed more uniformly. In the washing machine of the present invention, during the extraction process, the driving switch means connects the driving shaft and the outer shaft and rotates them integrally clockwise or counterclockwise. Therefore, during the rotation of the driving shaft, outer shaft, and wash-and-extraction tub at high speed, when the motor is stopped by an electromagnetic brake, the wash-and-extraction tub is also stopped almost at the same time via the driving shaft and the outer shaft. Consequently, a band-brake mechanism is not needed in order to immediately stop the wash-and-extraction tub during the extraction process, and the cost of the driving system can be reduced greatly. As described above, the washing machine of the present invention can be constructed without a brake mechanism for preventing the rotation of the outer shaft. It is of course possible to provide the brake mechanism. In this case, the brake should be released for letting the outer shaft rotate freely during the washing and rinsing processes, whereas, the brake should halt the outer shaft when the extraction process ends. In the washing machine of the present invention, the driving switch mechanism may be constructed to include: driving side engaging means rotated with the driving shaft, driven side engaging means rotated with the outer shaft and engageable and disengageable with the driving side engaging means, a second motor, a cam on a substantially circular disc rotated with the second motor, and shaft connecting means connecting or disconnecting the driven side engaging means and the driving side engaging means corresponding to the rotation of the cam, and the washing machine further comprises valve operation means for closing or opening a drain valve according to the rotation of the cam corresponding to a connection or disconnection of the driven side engaging means and the driving side engaging means. When the second motor is driven during the washing or rinsing process, the shaft connecting means receives a force from the rotating cam and the engagement between the driving side engaging means and the driven side engaging means is released. Then, the direct connection between the driving shaft and the outer shaft is released, and as described above, the agitator and the wash-and-extraction tub rotate in opposite directions. At the same time, the valve operation means receives a force from the cam and closes the drain valve. By this means, water can be stored in the wash-and-extraction tub. During the extraction process, on the other hand, when the cam is further rotated by the second motor, the shaft connecting means connects the driving side engaging means and the driven side engaging means so that the driving shaft and the outer shaft are connected, and the valve operation means opens the drain valve. Thus, the wash-and-extraction tub and the agitator rotate together at high speed and the water stored in the wash-and-extraction tub is drained to the outside. By this construction, not only the connection and disconnection of the shaft but also the open/close operation of the drain valve are controlled with the second motor and the cam. As a result, the driving system and the drain valve are integrated to become simple in structure, and the cost can be reduced. Furthermore, the control process is simplified because the both operations can be controlled at the same time by driving the second motor. The washing machine of the present invention may be constructed so that: it fiirther includes a loop transmission mechanism including: the motor, a small pulley placed on the motor shaft, a large pulley placed on the driving shaft, and a belt looping around the small pulley and large pulley; the driving side engaging means is constructed as an engaging hole formed in the large pulley; the driven side engaging means is constructed as a movable body with the outer shaft inserted inside, slidable along the outer shaft, and having a claw on the face to the large pulley; and the claw and the engaging hole are curved along a circle concentric with the driving shaft. By the above construction, the engagement process includes steps of sliding the movable body along the driving shaft toward the large pulley and inserting the claw into the engaging hole of the large pulley to engage the both means together. If the claw is out-positioned from the engaging hole along the circle, the claw collides with the face of the large pulley. When, however, the displacement is not large, the claw can be easily inserted into the engaging hole by rotating either the driving shaft or the outer shaft slightly because the claw and the engaging hole are curved as described above and hence overlap each other by a large part thereof. In a preferable construction of the washing machine of the present invention, the large pulley is formed with two metal plates clamped together, and both circumferential ends of the engaging hole are wrap-clamped. When the claw of the movable body touches the large pulley as described above, the force working on the engaging hole is greatest at the both circumferential ends. By wrap-clamping the both ends, the strength of the parts increases because the number of metal plates increases. As a result, the parts are hardly broken or deformed, so that the reliability is increased. In a preferable mode of the washing machine of the present invention, the control process is carried out so that, in changing from the washing or rinsing process to the extraction process, the second motor is operated to engage the driven side engaging means with the driving side engaging means, and the second motor is controlled to rotate the driving shaft little by little. According to this control, even in case the claw of the movable body is not completely inserted into the engaging hole of the large pulley but contacts the large pulley, the claw reaches the position to be inserted into the engaging hole and is inserted into it while the driving shaft is being rotated little by little. Thus, the outer shaft is assuredly connected to the large pulley. In the above-described washing machine, in case the cam does not reach the preset rotary position within a preset time period after starting the second motor, it is assumed that an abnormal condition such as breakdown or swallow of a foreign object has occurred. Taking this into account, the washing machine according to the present invention may be preferably provided with: detection means for detecting a preset rotary position of the cam, and determining means for determining whether a detection signal is obtained in the detection means within a preset time period from the time the second motor is started. When, for example, no detection signal is obtained with the determining means within the preset time period, it is preferable to stop the operation, inform the user of the abnormal condition and warn. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a vertical sectional view of the whole structure of a washing machine of an embodiment of the present invention. Fig. 2 is an external side view of the driving system of the washing machine of the embodiment. Fig. 3 is an external bottom view of the driving system of the washing machine of the embodiment. Fig. 4 is a partially sectional side view of the driving system of the washing machine of the embodiment (the condition of washing and rinsing process). Fig: 5 is a partially sectional side view of the driving system of the washing machine of the embodiment (the condition of extraction process). Figs. 6A and 6B show the operation of a drain valve in the washing machine of the embodiment. Figs. 7A-7D show the detailed structure of a large pulley in the washing machine of the embodiment, where Fig. 7A is a plan view. Fig. 7B is a cross sectional view at line A-A' of Fig. 7A, Fig. 7C is an enlarged view of part C of Fig. 7A, and Fig. 7D is a cross sectional view at line B-B' of Fig. 7C. Fig. 8 shows the construction of the electrical system of the main part of the washing machine of the embodiment. Fig. 9 is a flowchart showing a standard process of washing of the washing machine of the embodiment. Fig. 10 is a flowchart showing the control after the end of the washing process or stored-water rinsing process until the end of the extraction process in a washing machine of the embodiment. Fig. 11 is a simplified perspective view of a water current generated in a wash-and-extraction tub during washing or rinsing process in the washing machine of the embodiment. Fig. 12 shows the relation between the driving pattern of the motor 14 and the state of rotation of the agitator 5 and wash-and-extraction tub 3 in the washing machine of the embodiment. Fig. 13 is a simplified schematic diagram showing the relation of the components of the driving system in the washing machine of the embodiment. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT An embodiment of the washing machine of the present invention is described referring to the attached drawings. Fig. 1 shows a vertical section of the whole structure of the washing machine of the embodiment. Inside an outer housing 1, a cylindrical outer tub 2 with a closed bottom is suspended by a plurality of supporting rods not shown in the figure. By this means, the vibration of the outer tub 2 is prevented from being transmitted to the outer housing 1. Inside the outer tub 2, a wash-and-extraction tub 3 with a large number of water perforations on its circumference is rotatably supported on a supporting shaft 4 fixed on the bottom. On the inner bottom of the wash-and-extraction tub 3, an agitator 5 is rotatably placed on an inner shaft 6 fit in the supporting shaft 4. At the upper rear part of the outer housing 1, a water supply pipe 7 is placed and connected to an outside faucet. When a water supply valve 8 is opened, the water fed through the water supply pipe 7 flows into a water supply port 9 equipped with a detergent container and pours into the outer tub 2, At the bottom of the outer tub 2, a drain port 10 is provided and a drain pipe 11 connected to the drain port 10 is opened or closed by a drain valve 12. On the lower face of the outer tub 2, a driving system 13 is provided, which drives the wash-and-extraction tub 3 and the agitator 5 to rotate and conducts open/close operation of the drain valve 12. That is, the driving system 13 includes the following elements: a motor 14 attached on the lower face of the outer tub 2, a small pulley fixed to the motor shaft 15 of the motor 14, a large pulley 18, a belt 17 looping around the small pulley 16 and large pulley 18, a reduction mechanism 19 for transmitting the rotary power of the motor 14 transmitted via the small pulley 16, the belt 17 and large pulley 18, to the supporting shaft 4 and inner shaft 6. Furthermore, it includes a torque motor 20 to control the open/close operation of the drain valve 12 and the connect/disconnect operation (so-called clutch operation) of a shaft in the reduction mechanism 19. The large opening at the top of the outer housing 1 is a clothes-loading opening 21 equipped with a lid 22 for opening and closing it, and in front is provided a locking mechanism 23 operative to lock the lid 22 and prevent it from opening when the lid 22 is closed. The present washing machine is constructed to lock the lid 22 in the closed state with the locking mechanism 23 basically during the extracting operation (that is, while the wash-and-extraction tub 3 is rotated for extraction). Next, the structure of the above-described driving system 13 is described in detail. Fig. 2 is an external side view, Fig. 3 is an external view of the bottom, and Figs. 4 and 5 are partially sectional side views, where Fig. 4 shows the situation of washing and rinsing process and Fig. 5 shows the situation of extraction process. Fig. 13 is a simplified schematic diagram showing the relation of the components of the driving mechanism 13. As shown in Figs. 4 and 5, in the bottom 2a of the outer tub 2 are secured an upper bearing 30 and an oil seal 31, by which the hollow supporting shaft 4 is watertightly and rotatably supported. The wash-and-extraction tub 3 is fixed to the supporting shaft 4, as described above. Inside the supporting shaft 4, the inner shaft 6 with the agitator 5 fixed to its upper end is rotatably inserted. To the outside of the lower end of the supporting shaft 4, a gear case 32 is fixed which is composed of an upper case 32a and a lower case 32b. Inside the gear case 32, a gear mechanism 37 is contained. The gear mechanism 37 is operative to receive the rotary power from a driving shaft 31 having the large pulley 18 fixed to the lower end, and to transmit the power to the irmer shaft 6 at a preset reduction gear ratio. The circumference of the gear case 32 is enclosed with a cover 35 fixed by a bolt 34 to the lower face of the outer tub 2, and the gear case 32 is rotatably supported by a lower bearing 36 fixed to the cover 35. That is, the supporting shaft 4 and the gear case 32 function as an outer shaft for the rotary driving of the wash-and-extraction tub 3. The gear mechanism 37 is composed of: a sun gear 38 fixed to the upper end of the driving shaft 33, an intemal gear 39 placed on the inside wall of the large-diameter part of the upper case 32a, planetary gears 40 rotating around the sun gear 38 engaged with both the sun gear 38 and intemal gear 39, and a gear holder 42 fixed to the lower end of the inner shaft 6 and holding the rotation shafts 41 of the planetary gears 40. In this embodiment, the intemal gear 39 is a ring-shaped member independent of the upper case 32a, having vertical ridges (or grooves) on the outside of the circumference to be engaged with vertical grooves (or ridges) formed on the inside wall of the large-diameter part of the upper case 32a, and is embraced and fixed in the enlarged part. Teeth of the intemal gear may be otherwise directly formed on the inside wall of the large-diameter part of the upper case 32a. Between the cover 35 and the large pulley 18 is provided a clutch mechanism for switching the rotary power of the motor 14 supplied through the large pulley 18 to be transmitted to or shut off the outer shaft (to be precise, the lower case 32b). The clutch mechanism includes: a movable body 43 penetrated by the small-diameter part of the lower case 32b and having a plurality of claws 434 projecting downward, and a plurality of engaging holes 184 formed on the inner circumference of the large pulley 18 into which the claws 434 drop. The movable body 43 includes: a disk-shaped part 431, an inner cylinder 432 placed at the center of the disk-shaped part 431 penetrated by the lower case 32b, and an outer cylinder 433 formed on the lower face of the disk-shaped part 431, and the claws 434 are formed at the lower end of the outer cylinder 433. A recess 321 extending parallel to the shaft (i.e. in the vertical direction) is formed on the lower outer circumference of the lower case 32b, and a protrusion to be loosely fit into the recess 321 is formed on the inner circumference of the iimer cylinder 432 of the movable body 43. By means of such a loose fitting of the protrusion and the recess 321, the movable body 43 not only rotates with the gear case 32 but also is slidable in the vertical direction. Though not shown in figures, a spring is provided for urging the movable body 43 upwards, or in the direction away from the large pulley 18. Therefore, in the condition where no particular force is exerted on the movable body 43 from outside, the movable body 43 is pushed up to the highest position within the slidable range due to the urging force of the spring, as shown in Fig. 4. Figs. 7A-7D show the detailed structure of the large pulley 18, where Fig. 7A is a plan view. Fig. 7B is a cross sectional view at line A-A' of Fig. 7A, Fig. 7C is an enlarged view of part C of Fig. 7A, and Fig. 7D is a cross sectional view at line B-B' of Fig. 7C. As shown in Fig. 7B, the large pulley 18 is constructed by putting together a pair of metal plates 181 and 182 and fixing them mainly at the six round clamping holes 183 on the side of the outer circumference. The four engaging holes 184 are provided in the inner circumference of the large pulley 18 in the form of concentric arcs curved along a circle. As shown in Figs. 7C and 7D, the engaging hole 184 is constructed so that it is clamped at its both circumferential ends 185. As will be described later, the clutch mechanism does not decide the position of the engaging hole 184 and the claw 434 during the coupling operation. Consequently, there is a high possibility that the claw 434 strongly collides with the plate on the coaxial circumference of the engaging hole 184. Especially the both ends 185 of the engaging hole 184 undergo a great force. Therefore, the both ends 185 are wrap-clamped as described above, so that the thickness of the plate of the part is increased substantially and the strength is accordingly improved. As shown in Fig. 7D, the edge 185a of the both ends 185 is formed round as a result of the wrap-clamping. Thus, the claw 434 is easy to drop into the engaging hole 184 when it slides on it. Of course, it is also possible to shape the comer 185a round by any manufacturing method other than wrap-clamping. A clutch lever 44 is rotatably provided on a horizontal shaft 46 of a clutch supporting body 45 fixed to the cover 35, and the movable body 43 is engaged with one end of the clutch lever 44 (the end 44a on the side of the movable body 43). The clutch lever 44 is urged in the direction of arrow Ml in Fig. 2 by a torsion coil spring 47 placed around the shaft 46. To the other end of the clutch lever 44 (the end 44b on the side of the motor), one end of the coupling rod 48 is rotatably secured. To the motor shaft 49 of the torque motor 20, a cam 50 is attached. The cam 50 is a disc-shaped member whose lower face is formed into a slope 51 inclining along a direction, where an eccentric groove 52 is formed. The upper end of the linking rod 48 is slidably linked to the groove 52 and moves up and down along the slope 51 corresponding to the rotation of the cam 50. As shown in Figs. 6A and 6B, the upper end of another linking rod 53 is fixed to the cam 50 at a position inner than the groove 52, and an actuating rod 54 is linked to the lower end of the linking rod 53 in such a manner that it is rotatable around a vertical axis. At the tip of the actuating rod 54, a valve element 55 is attached, which is slidably inserted into a cylindrical valve chamber 56. Thus, according to the rotation of the came 50, the valve element 55 slides horizontally and opens or closes the pipe 11a leading to the drain port 10. In the wash and rinsing process, the driving system 13 operates as follows. During this process, as shown in Figs. 2 and 4, the slope 51 of the cam 50 is set at such a position where the linking rod 48 is at the lowest position. By these means, the motor-side end 44b of the clutch lever 44 is pushed downward via the rod 48, while the other end 44a of the clutch lever 44 is pushed upward against the urging force of the torsion coil spring 47. In this state, no force acts on the movable body 43 to push it down, the movable body 43 is pushed upward by the urging force of the coil not shown in the figure, as described above. Therefore, the claws 434 of the movable body 43 does not drop into the engaging holes 184 of the large pulley 18 and the rotation of the driving shaft 33 is not directly transmitted to the gear case 32. Meanwhile, as shown in Fig. 13, the rotation of the driving shaft 33 is transmitted via the sun gear 38 to the planetary gears 40, and the planetary gears 40, rotating on its own axis, revolves around the sun gear 38. The revolution is transmitted to the inner shaft 6 via the gear holder 42 and drives the inner shaft 6 to rotate at low speed. Thus, the agitator 5 fixed to the inner shaft 6 is rotated at low speed. There, the gear case 32 receives from the internal gear 39 a reaction force in the direction opposite to the revolution and rotation of the planetary gears 40. In this situation, the gear case 32 and the inner shaft 4 are allowed to rotate freely with respect to the outer tub 2 because the present washing machine is not equipped with a mechanism for preventing them from rotating in the washing and rinsing process. Therefore, due to the reaction force, the gear case 32 and the inner shaft 4 rotates in the direction opposite to the revolution of the planetary gears 40 or the rotating direction of the agitator 5. Also, during the washing and rinsing process, the valve element 55 is pushed into the valve chamber 56 by the actuating rod 54 and then closes the pipe 11a, as shown in Fig. 6A. Thus, the drain valve 12 is closed and the water supplied into the outer tub 2 is held in the outer tub 2. When the operation progresses from the washing or rinsing process to the extraction process, the torque motor 20 is driven and the cam 50 rotates by a preset angle. Then, as shown in Fig. 6B, the linking rod 53 moves in the direction away from the drain valve 12 and by these means the actuating rod 54 is drawn in the direction of the arrow M4. Next, the valve element 55 is separated from the face of the pipe wall, and the pipe 11a is opened. Thus, the water stored in the outer tub 2 runs through the drain port 10 and is discharged outside via the drain pipe 11. When the cam 50 is rotated as described above, the linking rod 48 is drawn upward, as shown in Fig. 5. Then, the end 44a of the clutch lever 44 is pushed downward by the urging force of the torsion coil spring 47, and by this force, the movable body 43 is descended against the urging force of the spring (not shown). When the claws 434 of the movable body 43 are at the position where they can exactly enter the engaging holes 184 of the large pulley 18, the movable body 43 descends to the lowest position, which leads to connect the gear case 32 and the large pulley 18. In this way, the large pulley 18, the gear case 32, and the supporting shaft 4 rotate together. Fig. 8 shows the electrical system of the main part of the washing machine of the present embodiment. At the center of the control, a controller 60 is placed which is composed of central processing unit (CPU), random access memory (RAM), read-only memory (ROM), timer and others. The controller 60 receives signals including: an operation signal from an operation part 32 composed of a plurality of operation keys, a water level detection signal from a water level sensor 64 for detecting the water level in the wash-and-extraction tub 3, and ON/OFF signals from a washing-position detecting switch 651 and an extracting-position detecting switch 652 attached to the cam 50 respectively. The controller 60 produces a display control signal for driving a display 63. Further, the controller 60 controls the motor 14, torque motor 20, water supply valve 8, and a solenoid 66 for releasing the cover lock through a load driver 61. As described above, the torque motor 20 controls the operation of both the clutch mechanism and the drain valve 12. Fig. 9 is a flowchart showing the standard washing process of the washing machine of the present invention. Here the outline of the operation of the washing machine is described referring to Fig. 9. At the start of a washing process, water is supplied to the preset level in the wash-and-extraction tub 3. Then, the washing process is carried out by rotating the agitator 5 in both directions at preset speed and by rotating the wash-and-extraction tub 3 in the opposite direction to the agitator 5 (Step S21). After the washing process is over, the torque motor 20 is driven, whereby the drain valve 12 is opened, and the large pulley 18 and the gear case 32 are connected by the movable body 43. In this way, the water in the wash-and-extraction tub 3 is drained. Then, an intermediate extraction process is carried out by rotating the wash-and-extraction tub 3 and the agitator 5 together at high speed (Step S22). By the intermediate extraction process, detergent water soaked in the laundry is scattered and removed. Next, as the first rinsing process, a rinse-with-extraction is carried out (Step S23). In the rinse-with-extraction, a shower of water is sprinkled from the water supply port 9 over the laundry while the wash-and-extraction tub 3 is rotated so that the laundry gets soaked with clean water and the detergent water is squeezed out of the laundry instead. After the laundry is soaked with the water sufficiently, the intermediate extraction process is carried out in Step 24 similar to Step 22, whereby the water soaked in the laundry is scattered. After the intermediate extraction process, the torque motor 20 is driven again, the drain valve 12 is closed and at the same time, the connection between the large pulley 18 and gear case 32 is released. Furthermore, as the second rinsing process, a stored-water rinsing is carried out (Step S25), where a preset amount of water is supplied into the wash-and-extraction tub 3, and the agitator 5 and the wash-and-extraction tub 3 are rotated in opposite directions as in the washing process of Step S21. After the stored-water rinsing is over, the final rinsing is carried out (Step S26), where the torque motor 20 is driven to open the drain valve 12 and discharge the water in the wash-and-extraction tub 3, and the wash-and-extraction tub 3 and the agitator 5 are rotated together at high speed, as in the intermediate extraction process. The above-described steps are general ones and may be changed as desired taking account of the type of the laundry or other factors. For example, another stored-water rinsing may be carried out in place of the rinse-with-extraction, the rinse-with-extraction may be carried out twice before the stored-water rinsing, or a flowing-water-rinsing may be carried out in place of the stored-water rinsing. Next, the control after the end of the washing process or stored-water rinsing process until the end of the extraction process (above-described Steps S22 and S26) is described in detail. Fig. 10 is a flowchart conceming the control. In the step of draining water after the end of the washing process or stored-water rinsing process, the controller 60 turns on the torque motor 20 via the load driver 61 (Step SI). After that, the controller 60 determines whether the extracting-position detecting switch 652 has been on (Step S2). When the switch 652 is detected to have been on, the controller 60 turns off the torque motor 20 (Step S3). When, in Step S2, the switch 652 is not detected to have been on, the controller 60 determines whether a preset operation time limit has lapsed since the turn-on of the torque motor 20 (Step S13). When the operation time limit has not lapsed, the operation retums to Step S2. When, in Step S13, the operation time limit has lapsed, it is determined that the operation is out of order due to an abnormal operation of the torque motor 20, abnormality of the switch 652 or some other causes. In such a case, the controller 60 turns off the torque motor 20, stops the operation and alarms of the abnormality (Steps S15, S16). The alarm may be an indication by turning a lamp on or on and off, an alarm sound of a buzzer or the like, or both. In Step S3, when the torque motor 20 is turned off, the movable body 43 is urged downwards, as described above. There, the claws 434 are not always inserted into the engaging holes 184 of the large pulley 18 but may contact the flat part of the large pulley 18. Taking this into account, the controller 60 controls the motor 14 via the load driver 61 so that the motor 14 is periodically turned on and off three times, where each period consists of 0.2 seconds of ON and 0.8 seconds OFF (Step S4). By such a process, the large pulley 18 rotates little by little. Thus, even when the claws 434 are not inserted into the engaging holes 184 before the rotation, the claws 434 come to a position where they can be inserted into the engaging holes 184, and the large pulley 18 and the gear case 32 are assuredly connected by the movable body 43. Next, the controller 60 determines by the level detection signal of the water level sensor 64 whether the water is drained to a preset level (Step S5). After the completion of the draining, the controller 60 carries out an intermittent extraction process (Step S6), and then a continuous extraction process (Step S7). When a preset continuous extraction time has lapsed, the controller 60 forcefully stops the motor 14 by energizing an electromagnetic brake attached to the motor 14 (Step S8). When the motor 14 stops rotating, the driving shaft 33 also stops rotating and, further, the gear case 32, the supporting shaft 4 and the wash-and-extraction tub 3, which are mechanically connected to the driving shaft 33 by means of the movable body 43, also stop rotating. When it is confirmed that the wash-and-extraction tub 3 has stopped ("Y" in Step S9), the controller 60 turns on the torque motor 20 for disconnecting the large pulley 18 and the gear case 32 from each other and closing the drain valve 12 (Step S10). After that, the controller 60 determines whether the washing-position detecting switch 651 has been on (Step S11). When the switch 651 is not detected to have been on, the controller 60 determines whether a preset operation time limit has lapsed since the turn-on of the torque motor 20 (Step S17). When the operation time limit has lapsed, the process goes to the above-described Step S14. When the operation time limit has not lapsed, the process returns to Step S1 1. When, in Step S1 1, it is determined that the washing-position detecting switch 651 has been on, the controller 60 turns off the torque motor 20 (Step S12). By this operation, the movable body 43 is lifted by the clutch lever 44, whereby the large pulley 18 and the gear case 32 are disconnected from each other and the drain valve 12 is closed. Thus, by the present washing machine, by limiting the operation time of the torque motor 20, not only the breakdown of the torque motor 14, switches or other elements but also an abnormal operation caused by a foreign object swallowed into the drain valve 12 or the like are detected. In the washing machine of the embodiment, the agitator 5 and the wash-and-extraction tub 3 rotate in the opposite directions in the course of the washing process or stored-water rinsing process, as described above, and the performance of washing and rinsing obtained thereby is higher than in conventional cases. In addition to that, for improving the washing or rinsing performance more, the motor 14 is controlled as follows. Fig. 11 is a simplified perspective view showing water current generated in the wash-and-extraction tub 3 during the washing or rinsing process. As described above, in the course of the washing or rinsing process, the wash-and-extraction tub 3 rotates in the direction of M6 opposite to the rotary direction M5 of the agitator 5. As the agitator 5 is placed at the bottom of the wash-and-extraction tub 3, the water current generated in the lower part of the water stored in the wash-and-extraction tub 3 flows in the same direction as the rotation of the agitator 5. Therefore, the laundry moving on the water current contacts the inner wall of the wash-and-extraction tub 3 rotating in the opposite direction, and is washed (or rinsed) with a high performance. On the other hand, in the upper part away from the agitator 5 and along the inner wall of the wash-and-extraction tub 3, the water current flows not in the rotary direction M5 of the agitator 5, but in the rotary direction M6 of the wash-and-extraction tub 3. Therefore, the dirt-removing effect by the friction between the laundry and inner wall of the wash-and-extraction tub 3 is not adequate. Thus, the present washing machine is constructed so that, in the process of rotating the motor 14 clockwise and counterclockwise, the rotating direction of the motor 14 is reversed while the wash-and-extraction tub 3 is rotating due to inertia, or before the wash-and-extraction tub 3 completely halts. When the rotation of the motor 14 is reversed, the rotation of the wash-and extraction tub 3 is immediately reversed and opposes the movement of the laundry on the water current flowing due to inertia for a short time period. Fig. 12 shows the relation between the driving pattern of the motor 14 and the state of rotation of the agitator 5 and wash-and-extraction tub 3. As shown by time-chart (a) of Fig. 12, the motor 14 is driven by a periodical pattern, where each period consists of tl seconds of clockwise-ON, t2 seconds of OFF, tl seconds of counterclockwise-ON, and t2 seconds of OFF. When the motor 14 is turned off, the wash-and-extraction tub 3 continues rotating by inertia, and t2 is determined so that the motor 14 is turned on before the end of the inertial rotation. At the moment the motor 14 is turned on, the rotary direction of the wash-and-extraction tub 3 is reversed, whereas the water current caused by the inertial rotation cannot follow the reversal immediately. As a result, the direction of the water current and the rotary direction of the wash-and-extraction tub 3 become opposite to each other for a short period of time. Thus, the effect of removing dirt from the laundry placed at higher position is further improved. The above-described embodiment is one example, and it is obvious that it can be changed or modified properly within the scope of the gist of the present invention. WHAT IS CLAIMED IS: 1. A washing machine with a wash-and-extraction tub rotatably provided in an outer tub and an agitator rotatably provided on an inner bottom of the wash-and-extraction tub, characterized by comprising: a) a hollow outer shaft rotating with the wash-and-extraction tub, b) an inner shaft inserted in the outer shaft and rotating with the agitator, c) a driving shaft provided coaxially with the outer shaft and inner shaft, and driven to rotate by a motor, d) reduction means including: an internal gear formed with or connected to the outer shaft, a sun gear formed with or connected to the driving shaft, and planetary gears connected to the inner shaft and engaging and rotating with the internal gear and the sun gear, and e) driving switch means for connecting or disconnecting the driving shaft and the outer shaft, wherein, during a washing or rinsing process, the driving shaft is disconnected from the outer shaft by the driving switch means while the driving shaft and the outer shaft are connected via the sun gear, planetary gears and internal gear, so that the agitator is rotated in a preset direction, and, with the rotation of the agitator, the wash-and-extraction tub is rotated in a direction opposite to the preset direction by a reaction force of the planetary gears working on the internal gear. 2. The washing machine according to claim 1, characterized by not comprising a brake mechanism for preventing the rotation of the outer shaft. 3. The washing machine according to claim 1, characterized by comprising a brake mechanism for preventing the rotation of the outer shaft, wherein the brake is released for letting the outer shaft rotate freely during the washing or rinsing process, and the brake halts the outer shaft when the extraction process ends. 4. The washing machine according to claim 1 or 2, characterized in that: the driving switch means comprises: driving side engaging means rotated with the driving shaft, driven side engaging means rotated with the outer shaft and engageable or disengageable with the driving side engaging means, a second motor, a cam on a substantially circular disc rotated with the second motor, and shaft connecting means for connecting or disconnecting the driven side engaging means and the driving side engaging means corresponding to the rotation of the cam, and the washing machine further comprises valve operation means for closing or opening a drain valve according to the rotation of the cam corresponding to a connection or disconnection of the driven side engaging means and the driving side engaging means. 5. The washing machine according to claim 4, characterized by: ftirther comprising a loop transmission mechanism including: the motor, a small pulley fixed on the motor shaft, a large pulley fixed on the driving shaft, and a belt looping around the small pulley and the large pulley; the driving side engaging means is constructed as an engaging hole formed in the large pulley; the driven side engaging means is constructed as a movable body with the outer shaft inserted inside, slidable along the outer shaft, and having a claw on the face to the large pulley; and the claw and the engaging hole are curved along a circle concentric with the driving shaft. 6. The washing machine according to claim 5, characterized in that the large pulley is formed with two metal plates clamped together, and both circumferential ends of the engaging hole are wrap-clamped. 7. The washing machine according to one of claims 4-6, characterized in that, in changing from the washing or rinsing process to the extraction process, the second motor is operated to engage the driven side engaging means with the driving side engaging means, and the second motor is controlled to rotate the driving shaft little by little. 8. The washing machine according to one of claims 4-7, characterized by further I comprising: detection means for detecting a preset rotary position of the cam, and determining means for determining whether a detection signal is obtained in the detection means within a preset time period from the time the second motor is started. 9. A washing machine substantially as herein described with reference to the accompanying drawings.

Full Text

The present invention relates to a washing machine and, more precisely, to an automatic washing machine provided with a wash-and-extraction tub placed rotatably in an outer tub and an agitator placed rotatably on the inner bottom of the wash-and-extraction tub.
BACKGROUND OF THE INVENTION
In a conventional and general type of automatic washing machine, during the course of washing and rinsing process, only the agitator placed on the inner bottom of the wash-and-extraction tub is driven to rotate back and forth at low speed, while, during the course of the extraction process, both the wash-and-extraction tub and the agitator are driven to rotate together unidirectionally at high speed. In order to switch the driving, many of conventional washing machines are provided with a clutch mechanism such as using a spring clutch in a driving mechanism. In such a clutch mechanism, the spring clutch is fastened solely in one direction so that the driving shaft is connected to a supporting shaft of the wash-and-extraction tub. Therefore, when the driving shaft is stopped during the high-speed rotation, the driving shaft is disconnected from the supporting shaft, and the wash-and-extraction tub continues rotating by inertia. For this reason, the driving system is provided with a band-brake mechanism in order to stop the wash-and-extraction tub immediately after the extraction process ends, or at other timings. The brake mechanism also has a function to prevent the wash-and-extraction tub from rotating together with the agitator during the course of washing or rinsing process.
However, the above-described clutch mechanism or band-brake mechanism is so complicated in structure that it has become one major reason for an increase in the production cost of a washing machine. Therefore, especially in a relatively inexpensive washing machine with simplified functions, there has been a great demand for omitting the band-brake mechanism as well as providing a driving system with a simplified structure of a clutch mechanism.
As described above, the wash-and-extraction tub is generally stationary during

washing or rinsing process. A washing machine has already been known, however, whose washing or rinsing performance is improved by rotating the wash-and-extraction tub actively at low speed in the direction opposite to the rotation of the agitator. In such a type of washing machine, the rotary driving power of the driving shaft is transmitted to the supporting shaft of the wash-and-extraction tub and to the shaft of the agitator via respective reduction mechanisms. As a result, the driving system has become more complicated than that of conventional washing machines, and impractical due to the cost. That is, the attempt to improve the washing or rinsing performance by the above-described method conflicts absolutely with the above-mentioned demand for simplifying the driving system of a washing machine.
The present invention is achieved in this respect placing its main object to simplify the structure of the driving system of a washing machine, and to provide a washing machine with an improved washing or rinsing performance.
SUMMARY OF THE INVENTION
The washing machine according to the present invention achieved to solve the above-described problems includes a wash-and-extraction tub rotatably provided in an outer tub and an agitator rotatably provided on the inner bottom of the wash-and-extraction tub, and is characterized by further including:
a) a hollow outer shaft rotating with the wash-and-extraction tub,
b) an inner shaft inserted in the outer shaft and rotating with the agitator,
c) a driving shaft provided coaxially with the outer shaft and inner shaft, and driven to rotate by a motor,
d) reduction means including:
an internal gear formed with or connected to the outer shaft, a sun gear formed with or connected to the driving shaft, and planetary gears connected to the inner shaft and engaging and rotating with the intemal gear and the sun gear, and
e) driving switch means for connecting or disconnecting the driving shaft and the outer

shaft,
wherein, during the washing or rinsing process, the driving shaft is disconnected from the outer shaft by the driving switch means while the driving shaft and the outer shaft are connected via the sun gear, planetary gears and internal gear, so that the agitator is rotated in a preset direction, and, with the rotation of the agitator, the wash-and-extraction tub is rotated in a direction opposite to the preset direction by a reaction force of the planetary gears working on the internal gear.
In the washing machine of the present invention, the outer shaft is disconnected from the driving shaft during the washing or rinsing process, and the outer shaft is not forcefully halted by a brake mechanism or the like, which is different from a conventional washing machine. This means that a brake mechanism for braking the outer shaft is not provided, or not used even if it is provided. At this time, the outer shaft is connected to the driving shaft via the internal gear, planetary gears and sun gear, and, as the driving shaft rotates, the outer shaft receives a load, or a reaction force, from the planetary gears in the direction opposite to the rotary direction. There, the outer shaft rotates in the opposite direction to the inner shaft due to the reaction force. Thus, the wash-and-extraction tub is rotated in the opposite direction to the agitator.
Therefore, as the wash-and-extraction tub rotates in the direction opposite to the moving direction of the laundry on the water current generated by the rotation of the agitator, the friction between the laundry and the wash-and-extraction tub increases and the washing and rinsing performance is improved. The thus-rotating wash-and-extraction tub generates water current opposite to that generated by the agitator, so that a turbulent flow is generated and vertical water current can be obtained with ease. As a result, the laundry changes its position up and down on the vertical water current, so that the washing or rinsing is performed more uniformly.
In the washing machine of the present invention, during the extraction process, the driving switch means connects the driving shaft and the outer shaft and rotates them integrally clockwise or counterclockwise. Therefore, during the rotation of the driving shaft, outer shaft, and wash-and-extraction tub at high speed, when the motor is stopped by an electromagnetic

brake, the wash-and-extraction tub is also stopped almost at the same time via the driving shaft and the outer shaft. Consequently, a band-brake mechanism is not needed in order to immediately stop the wash-and-extraction tub during the extraction process, and the cost of the driving system can be reduced greatly.
As described above, the washing machine of the present invention can be constructed without a brake mechanism for preventing the rotation of the outer shaft. It is of course possible to provide the brake mechanism. In this case, the brake should be released for letting the outer shaft rotate freely during the washing and rinsing processes, whereas, the brake should halt the outer shaft when the extraction process ends.
In the washing machine of the present invention, the driving switch mechanism may be constructed to include:
driving side engaging means rotated with the driving shaft,
driven side engaging means rotated with the outer shaft and engageable and disengageable with the driving side engaging means,
a second motor,
a cam on a substantially circular disc rotated with the second motor, and
shaft connecting means connecting or disconnecting the driven side engaging means and the driving side engaging means corresponding to the rotation of the cam, and the washing machine further comprises valve operation means for closing or opening a drain valve according to the rotation of the cam corresponding to a connection or disconnection of the driven side engaging means and the driving side engaging means.
When the second motor is driven during the washing or rinsing process, the shaft connecting means receives a force from the rotating cam and the engagement between the driving side engaging means and the driven side engaging means is released. Then, the direct connection between the driving shaft and the outer shaft is released, and as described above, the agitator and the wash-and-extraction tub rotate in opposite directions. At the same time, the valve operation means receives a force from the cam and closes the drain valve. By this

means, water can be stored in the wash-and-extraction tub. During the extraction process, on the other hand, when the cam is further rotated by the second motor, the shaft connecting means connects the driving side engaging means and the driven side engaging means so that the driving shaft and the outer shaft are connected, and the valve operation means opens the drain valve. Thus, the wash-and-extraction tub and the agitator rotate together at high speed and the water stored in the wash-and-extraction tub is drained to the outside. By this construction, not only the connection and disconnection of the shaft but also the open/close operation of the drain valve are controlled with the second motor and the cam. As a result, the driving system and the drain valve are integrated to become simple in structure, and the cost can be reduced. Furthermore, the control process is simplified because the both operations can be controlled at the same time by driving the second motor.
The washing machine of the present invention may be constructed so that: it fiirther includes a loop transmission mechanism including: the motor,
a small pulley placed on the motor shaft, a large pulley placed on the driving shaft, and a belt looping around the small pulley and large pulley; the driving side engaging means is constructed as an engaging hole formed in the large pulley;
the driven side engaging means is constructed as a movable body with the outer shaft inserted inside, slidable along the outer shaft, and having a claw on the face to the large pulley; and
the claw and the engaging hole are curved along a circle concentric with the driving shaft.
By the above construction, the engagement process includes steps of sliding the movable body along the driving shaft toward the large pulley and inserting the claw into the engaging hole of the large pulley to engage the both means together. If the claw is out-positioned from the engaging hole along the circle, the claw collides with the face of the large

pulley. When, however, the displacement is not large, the claw can be easily inserted into the engaging hole by rotating either the driving shaft or the outer shaft slightly because the claw and the engaging hole are curved as described above and hence overlap each other by a large part thereof.
In a preferable construction of the washing machine of the present invention, the large pulley is formed with two metal plates clamped together, and both circumferential ends of the engaging hole are wrap-clamped. When the claw of the movable body touches the large pulley as described above, the force working on the engaging hole is greatest at the both circumferential ends. By wrap-clamping the both ends, the strength of the parts increases because the number of metal plates increases. As a result, the parts are hardly broken or deformed, so that the reliability is increased.
In a preferable mode of the washing machine of the present invention, the control process is carried out so that, in changing from the washing or rinsing process to the extraction process, the second motor is operated to engage the driven side engaging means with the driving side engaging means, and the second motor is controlled to rotate the driving shaft little by little. According to this control, even in case the claw of the movable body is not completely inserted into the engaging hole of the large pulley but contacts the large pulley, the claw reaches the position to be inserted into the engaging hole and is inserted into it while the driving shaft is being rotated little by little. Thus, the outer shaft is assuredly connected to the large pulley.
In the above-described washing machine, in case the cam does not reach the preset rotary position within a preset time period after starting the second motor, it is assumed that an abnormal condition such as breakdown or swallow of a foreign object has occurred. Taking this into account, the washing machine according to the present invention may be preferably provided with:
detection means for detecting a preset rotary position of the cam, and

determining means for determining whether a detection signal is obtained in the detection means within a preset time period from the time the second motor is started.
When, for example, no detection signal is obtained with the determining means within the preset time period, it is preferable to stop the operation, inform the user of the abnormal condition and warn.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a vertical sectional view of the whole structure of a washing machine of an embodiment of the present invention.
Fig. 2 is an external side view of the driving system of the washing machine of the embodiment.
Fig. 3 is an external bottom view of the driving system of the washing machine of the embodiment.
Fig. 4 is a partially sectional side view of the driving system of the washing machine of the embodiment (the condition of washing and rinsing process).
Fig: 5 is a partially sectional side view of the driving system of the washing machine of the embodiment (the condition of extraction process).
Figs. 6A and 6B show the operation of a drain valve in the washing machine of the embodiment.
Figs. 7A-7D show the detailed structure of a large pulley in the washing machine of the embodiment, where Fig. 7A is a plan view. Fig. 7B is a cross sectional view at line A-A' of Fig. 7A, Fig. 7C is an enlarged view of part C of Fig. 7A, and Fig. 7D is a cross sectional view at line B-B' of Fig. 7C.
Fig. 8 shows the construction of the electrical system of the main part of the washing machine of the embodiment.
Fig. 9 is a flowchart showing a standard process of washing of the washing machine of the embodiment.
Fig. 10 is a flowchart showing the control after the end of the washing process or stored-water rinsing process until the end of the extraction process in a washing machine of

the embodiment.
Fig. 11 is a simplified perspective view of a water current generated in a wash-and-extraction tub during washing or rinsing process in the washing machine of the embodiment.
Fig. 12 shows the relation between the driving pattern of the motor 14 and the state of rotation of the agitator 5 and wash-and-extraction tub 3 in the washing machine of the embodiment.
Fig. 13 is a simplified schematic diagram showing the relation of the components of the driving system in the washing machine of the embodiment.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
An embodiment of the washing machine of the present invention is described referring to the attached drawings.
Fig. 1 shows a vertical section of the whole structure of the washing machine of the embodiment. Inside an outer housing 1, a cylindrical outer tub 2 with a closed bottom is suspended by a plurality of supporting rods not shown in the figure. By this means, the vibration of the outer tub 2 is prevented from being transmitted to the outer housing 1. Inside the outer tub 2, a wash-and-extraction tub 3 with a large number of water perforations on its circumference is rotatably supported on a supporting shaft 4 fixed on the bottom. On the inner bottom of the wash-and-extraction tub 3, an agitator 5 is rotatably placed on an inner shaft 6 fit in the supporting shaft 4. At the upper rear part of the outer housing 1, a water supply pipe 7 is placed and connected to an outside faucet. When a water supply valve 8 is opened, the water fed through the water supply pipe 7 flows into a water supply port 9 equipped with a detergent container and pours into the outer tub 2, At the bottom of the outer tub 2, a drain port 10 is provided and a drain pipe 11 connected to the drain port 10 is opened or closed by a drain valve 12.
On the lower face of the outer tub 2, a driving system 13 is provided, which drives the wash-and-extraction tub 3 and the agitator 5 to rotate and conducts open/close operation of the drain valve 12. That is, the driving system 13 includes the following elements:

a motor 14 attached on the lower face of the outer tub 2,
a small pulley fixed to the motor shaft 15 of the motor 14,
a large pulley 18,
a belt 17 looping around the small pulley 16 and large pulley 18,
a reduction mechanism 19 for transmitting the rotary power of the motor 14 transmitted via the small pulley 16, the belt 17 and large pulley 18, to the supporting shaft 4 and inner shaft 6. Furthermore, it includes a torque motor 20 to control the open/close operation of the drain valve 12 and the connect/disconnect operation (so-called clutch operation) of a shaft in the reduction mechanism 19.
The large opening at the top of the outer housing 1 is a clothes-loading opening 21 equipped with a lid 22 for opening and closing it, and in front is provided a locking mechanism 23 operative to lock the lid 22 and prevent it from opening when the lid 22 is closed. The present washing machine is constructed to lock the lid 22 in the closed state with the locking mechanism 23 basically during the extracting operation (that is, while the wash-and-extraction tub 3 is rotated for extraction).
Next, the structure of the above-described driving system 13 is described in detail. Fig. 2 is an external side view, Fig. 3 is an external view of the bottom, and Figs. 4 and 5 are partially sectional side views, where Fig. 4 shows the situation of washing and rinsing process and Fig. 5 shows the situation of extraction process. Fig. 13 is a simplified schematic diagram showing the relation of the components of the driving mechanism 13.
As shown in Figs. 4 and 5, in the bottom 2a of the outer tub 2 are secured an upper bearing 30 and an oil seal 31, by which the hollow supporting shaft 4 is watertightly and rotatably supported. The wash-and-extraction tub 3 is fixed to the supporting shaft 4, as described above. Inside the supporting shaft 4, the inner shaft 6 with the agitator 5 fixed to its upper end is rotatably inserted. To the outside of the lower end of the supporting shaft 4, a gear case 32 is fixed which is composed of an upper case 32a and a lower case 32b. Inside the gear case 32, a gear mechanism 37 is contained. The gear mechanism 37 is operative to receive the rotary power from a driving shaft 31 having the large pulley 18 fixed to the lower end, and to transmit the power to the irmer shaft 6 at a preset reduction gear ratio. The

circumference of the gear case 32 is enclosed with a cover 35 fixed by a bolt 34 to the lower face of the outer tub 2, and the gear case 32 is rotatably supported by a lower bearing 36 fixed to the cover 35. That is, the supporting shaft 4 and the gear case 32 function as an outer shaft for the rotary driving of the wash-and-extraction tub 3.
The gear mechanism 37 is composed of: a sun gear 38 fixed to the upper end of the driving shaft 33,
an intemal gear 39 placed on the inside wall of the large-diameter part of the upper case 32a, planetary gears 40 rotating around the sun gear 38 engaged with both the sun gear 38 and intemal gear 39, and
a gear holder 42 fixed to the lower end of the inner shaft 6 and holding the rotation shafts 41 of the planetary gears 40.
In this embodiment, the intemal gear 39 is a ring-shaped member independent of the upper case 32a, having vertical ridges (or grooves) on the outside of the circumference to be engaged with vertical grooves (or ridges) formed on the inside wall of the large-diameter part of the upper case 32a, and is embraced and fixed in the enlarged part. Teeth of the intemal gear may be otherwise directly formed on the inside wall of the large-diameter part of the upper case 32a.
Between the cover 35 and the large pulley 18 is provided a clutch mechanism for switching the rotary power of the motor 14 supplied through the large pulley 18 to be transmitted to or shut off the outer shaft (to be precise, the lower case 32b). The clutch mechanism includes:
a movable body 43 penetrated by the small-diameter part of the lower case 32b and having a plurality of claws 434 projecting downward, and
a plurality of engaging holes 184 formed on the inner circumference of the large pulley 18 into which the claws 434 drop.
The movable body 43 includes: a disk-shaped part 431,
an inner cylinder 432 placed at the center of the disk-shaped part 431 penetrated by the lower case 32b, and

an outer cylinder 433 formed on the lower face of the disk-shaped part 431, and the claws 434 are formed at the lower end of the outer cylinder 433.
A recess 321 extending parallel to the shaft (i.e. in the vertical direction) is formed on the lower outer circumference of the lower case 32b, and a protrusion to be loosely fit into the recess 321 is formed on the inner circumference of the iimer cylinder 432 of the movable body 43. By means of such a loose fitting of the protrusion and the recess 321, the movable body 43 not only rotates with the gear case 32 but also is slidable in the vertical direction. Though not shown in figures, a spring is provided for urging the movable body 43 upwards, or in the direction away from the large pulley 18. Therefore, in the condition where no particular force is exerted on the movable body 43 from outside, the movable body 43 is pushed up to the highest position within the slidable range due to the urging force of the spring, as shown in Fig. 4.
Figs. 7A-7D show the detailed structure of the large pulley 18, where Fig. 7A is a plan view.
Fig. 7B is a cross sectional view at line A-A' of Fig. 7A, Fig. 7C is an enlarged view of part C of Fig. 7A, and Fig. 7D is a cross sectional view at line B-B' of Fig. 7C.
As shown in Fig. 7B, the large pulley 18 is constructed by putting together a pair of metal plates 181 and 182 and fixing them mainly at the six round clamping holes 183 on the side of the outer circumference. The four engaging holes 184 are provided in the inner circumference of the large pulley 18 in the form of concentric arcs curved along a circle. As shown in Figs. 7C and 7D, the engaging hole 184 is constructed so that it is clamped at its both circumferential ends 185. As will be described later, the clutch mechanism does not decide the position of the engaging hole 184 and the claw 434 during the coupling operation. Consequently, there is a high possibility that the claw 434 strongly collides with the plate on the coaxial circumference of the engaging hole 184. Especially the both ends 185 of the engaging hole 184 undergo a great force. Therefore, the both ends 185 are wrap-clamped as described above, so that the thickness of the plate of the part is increased substantially and the strength is accordingly improved. As shown in Fig. 7D, the edge 185a of the both ends 185 is formed

round as a result of the wrap-clamping. Thus, the claw 434 is easy to drop into the engaging hole 184 when it slides on it. Of course, it is also possible to shape the comer 185a round by any manufacturing method other than wrap-clamping.
A clutch lever 44 is rotatably provided on a horizontal shaft 46 of a clutch supporting body 45 fixed to the cover 35, and the movable body 43 is engaged with one end of the clutch lever 44 (the end 44a on the side of the movable body 43). The clutch lever 44 is urged in the direction of arrow Ml in Fig. 2 by a torsion coil spring 47 placed around the shaft 46. To the other end of the clutch lever 44 (the end 44b on the side of the motor), one end of the coupling rod 48 is rotatably secured. To the motor shaft 49 of the torque motor 20, a cam 50 is attached. The cam 50 is a disc-shaped member whose lower face is formed into a slope 51 inclining along a direction, where an eccentric groove 52 is formed. The upper end of the linking rod 48 is slidably linked to the groove 52 and moves up and down along the slope 51 corresponding to the rotation of the cam 50.
As shown in Figs. 6A and 6B, the upper end of another linking rod 53 is fixed to the cam 50 at a position inner than the groove 52, and an actuating rod 54 is linked to the lower end of the linking rod 53 in such a manner that it is rotatable around a vertical axis. At the tip of the actuating rod 54, a valve element 55 is attached, which is slidably inserted into a cylindrical valve chamber 56. Thus, according to the rotation of the came 50, the valve element 55 slides horizontally and opens or closes the pipe 11a leading to the drain port 10.
In the wash and rinsing process, the driving system 13 operates as follows. During this process, as shown in Figs. 2 and 4, the slope 51 of the cam 50 is set at such a position where the linking rod 48 is at the lowest position. By these means, the motor-side end 44b of the clutch lever 44 is pushed downward via the rod 48, while the other end 44a of the clutch lever 44 is pushed upward against the urging force of the torsion coil spring 47. In this state, no force acts on the movable body 43 to push it down, the movable body 43 is pushed upward by the urging force of the coil not shown in the figure, as described above. Therefore, the claws 434 of the movable body 43 does not drop into the engaging holes 184 of the large pulley 18 and the rotation of the driving shaft 33 is not directly transmitted to the gear case 32.

Meanwhile, as shown in Fig. 13, the rotation of the driving shaft 33 is transmitted via the sun gear 38 to the planetary gears 40, and the planetary gears 40, rotating on its own axis, revolves around the sun gear 38. The revolution is transmitted to the inner shaft 6 via the gear holder 42 and drives the inner shaft 6 to rotate at low speed. Thus, the agitator 5 fixed to the inner shaft 6 is rotated at low speed. There, the gear case 32 receives from the internal gear 39 a reaction force in the direction opposite to the revolution and rotation of the planetary gears 40. In this situation, the gear case 32 and the inner shaft 4 are allowed to rotate freely with respect to the outer tub 2 because the present washing machine is not equipped with a mechanism for preventing them from rotating in the washing and rinsing process. Therefore, due to the reaction force, the gear case 32 and the inner shaft 4 rotates in the direction opposite to the revolution of the planetary gears 40 or the rotating direction of the agitator 5. Also, during the washing and rinsing process, the valve element 55 is pushed into the valve chamber 56 by the actuating rod 54 and then closes the pipe 11a, as shown in Fig. 6A. Thus, the drain valve 12 is closed and the water supplied into the outer tub 2 is held in the outer tub 2.
When the operation progresses from the washing or rinsing process to the extraction process, the torque motor 20 is driven and the cam 50 rotates by a preset angle. Then, as shown in Fig. 6B, the linking rod 53 moves in the direction away from the drain valve 12 and by these means the actuating rod 54 is drawn in the direction of the arrow M4. Next, the valve element 55 is separated from the face of the pipe wall, and the pipe 11a is opened. Thus, the water stored in the outer tub 2 runs through the drain port 10 and is discharged outside via the drain pipe 11.
When the cam 50 is rotated as described above, the linking rod 48 is drawn upward, as shown in Fig. 5. Then, the end 44a of the clutch lever 44 is pushed downward by the urging force of the torsion coil spring 47, and by this force, the movable body 43 is descended against the urging force of the spring (not shown). When the claws 434 of the movable body 43 are at the position where they can exactly enter the engaging holes 184 of the large pulley 18, the movable body 43 descends to the lowest position, which leads to connect the gear case 32 and the large pulley 18. In this way, the large pulley 18, the gear case 32, and the

supporting shaft 4 rotate together.
Fig. 8 shows the electrical system of the main part of the washing machine of the present embodiment. At the center of the control, a controller 60 is placed which is composed of central processing unit (CPU), random access memory (RAM), read-only memory (ROM), timer and others. The controller 60 receives signals including: an operation signal from an operation part 32 composed of a plurality of operation keys, a water level detection signal from a water level sensor 64 for detecting the water level in the wash-and-extraction tub 3, and
ON/OFF signals from a washing-position detecting switch 651 and an extracting-position detecting switch 652 attached to the cam 50 respectively. The controller 60 produces a display control signal for driving a display 63. Further, the controller 60 controls the motor 14, torque motor 20, water supply valve 8, and a solenoid 66 for releasing the cover lock through a load driver 61. As described above, the torque motor 20 controls the operation of both the clutch mechanism and the drain valve 12.
Fig. 9 is a flowchart showing the standard washing process of the washing machine of the present invention. Here the outline of the operation of the washing machine is described referring to Fig. 9. At the start of a washing process, water is supplied to the preset level in the wash-and-extraction tub 3. Then, the washing process is carried out by rotating the agitator 5 in both directions at preset speed and by rotating the wash-and-extraction tub 3 in the opposite direction to the agitator 5 (Step S21). After the washing process is over, the torque motor 20 is driven, whereby the drain valve 12 is opened, and the large pulley 18 and the gear case 32 are connected by the movable body 43. In this way, the water in the wash-and-extraction tub 3 is drained. Then, an intermediate extraction process is carried out by rotating the wash-and-extraction tub 3 and the agitator 5 together at high speed (Step S22). By the intermediate extraction process, detergent water soaked in the laundry is scattered and removed.
Next, as the first rinsing process, a rinse-with-extraction is carried out (Step S23). In the rinse-with-extraction, a shower of water is sprinkled from the water supply port 9 over the laundry while the wash-and-extraction tub 3 is rotated so that the laundry gets soaked with

clean water and the detergent water is squeezed out of the laundry instead. After the laundry is soaked with the water sufficiently, the intermediate extraction process is carried out in Step 24 similar to Step 22, whereby the water soaked in the laundry is scattered. After the intermediate extraction process, the torque motor 20 is driven again, the drain valve 12 is closed and at the same time, the connection between the large pulley 18 and gear case 32 is released. Furthermore, as the second rinsing process, a stored-water rinsing is carried out (Step S25), where a preset amount of water is supplied into the wash-and-extraction tub 3, and the agitator 5 and the wash-and-extraction tub 3 are rotated in opposite directions as in the washing process of Step S21. After the stored-water rinsing is over, the final rinsing is carried out (Step S26), where the torque motor 20 is driven to open the drain valve 12 and discharge the water in the wash-and-extraction tub 3, and the wash-and-extraction tub 3 and the agitator 5 are rotated together at high speed, as in the intermediate extraction process.
The above-described steps are general ones and may be changed as desired taking account of the type of the laundry or other factors. For example, another stored-water rinsing may be carried out in place of the rinse-with-extraction, the rinse-with-extraction may be carried out twice before the stored-water rinsing, or a flowing-water-rinsing may be carried out in place of the stored-water rinsing.
Next, the control after the end of the washing process or stored-water rinsing process until the end of the extraction process (above-described Steps S22 and S26) is described in detail. Fig. 10 is a flowchart conceming the control.
In the step of draining water after the end of the washing process or stored-water rinsing process, the controller 60 turns on the torque motor 20 via the load driver 61 (Step SI). After that, the controller 60 determines whether the extracting-position detecting switch 652 has been on (Step S2). When the switch 652 is detected to have been on, the controller 60 turns off the torque motor 20 (Step S3). When, in Step S2, the switch 652 is not detected to have been on, the controller 60 determines whether a preset operation time limit has lapsed since the turn-on of the torque motor 20 (Step S13). When the operation time limit has not lapsed, the operation retums to Step S2. When, in Step S13, the operation time limit has lapsed, it is determined that the operation is out of order due to an abnormal operation of the

torque motor 20, abnormality of the switch 652 or some other causes. In such a case, the controller 60 turns off the torque motor 20, stops the operation and alarms of the abnormality (Steps S15, S16). The alarm may be an indication by turning a lamp on or on and off, an alarm sound of a buzzer or the like, or both.
In Step S3, when the torque motor 20 is turned off, the movable body 43 is urged downwards, as described above. There, the claws 434 are not always inserted into the engaging holes 184 of the large pulley 18 but may contact the flat part of the large pulley 18. Taking this into account, the controller 60 controls the motor 14 via the load driver 61 so that the motor 14 is periodically turned on and off three times, where each period consists of 0.2 seconds of ON and 0.8 seconds OFF (Step S4). By such a process, the large pulley 18 rotates little by little. Thus, even when the claws 434 are not inserted into the engaging holes 184 before the rotation, the claws 434 come to a position where they can be inserted into the engaging holes 184, and the large pulley 18 and the gear case 32 are assuredly connected by the movable body 43.
Next, the controller 60 determines by the level detection signal of the water level sensor 64 whether the water is drained to a preset level (Step S5). After the completion of the draining, the controller 60 carries out an intermittent extraction process (Step S6), and then a continuous extraction process (Step S7). When a preset continuous extraction time has lapsed, the controller 60 forcefully stops the motor 14 by energizing an electromagnetic brake attached to the motor 14 (Step S8). When the motor 14 stops rotating, the driving shaft 33 also stops rotating and, further, the gear case 32, the supporting shaft 4 and the wash-and-extraction tub 3, which are mechanically connected to the driving shaft 33 by means of the movable body 43, also stop rotating. When it is confirmed that the wash-and-extraction tub 3 has stopped ("Y" in Step S9), the controller 60 turns on the torque motor 20 for disconnecting the large pulley 18 and the gear case 32 from each other and closing the drain valve 12 (Step S10). After that, the controller 60 determines whether the washing-position detecting switch 651 has been on (Step S11). When the switch 651 is not detected to have been on, the controller 60 determines whether a preset operation time limit has lapsed since the turn-on of the torque motor 20 (Step S17). When the operation time limit has lapsed, the

process goes to the above-described Step S14. When the operation time limit has not lapsed, the process returns to Step S1 1.
When, in Step S1 1, it is determined that the washing-position detecting switch 651 has been on, the controller 60 turns off the torque motor 20 (Step S12). By this operation, the movable body 43 is lifted by the clutch lever 44, whereby the large pulley 18 and the gear case 32 are disconnected from each other and the drain valve 12 is closed.
Thus, by the present washing machine, by limiting the operation time of the torque motor 20, not only the breakdown of the torque motor 14, switches or other elements but also an abnormal operation caused by a foreign object swallowed into the drain valve 12 or the like are detected.
In the washing machine of the embodiment, the agitator 5 and the wash-and-extraction tub 3 rotate in the opposite directions in the course of the washing process or stored-water rinsing process, as described above, and the performance of washing and rinsing obtained thereby is higher than in conventional cases. In addition to that, for improving the washing or rinsing performance more, the motor 14 is controlled as follows.
Fig. 11 is a simplified perspective view showing water current generated in the wash-and-extraction tub 3 during the washing or rinsing process. As described above, in the course of the washing or rinsing process, the wash-and-extraction tub 3 rotates in the direction of M6 opposite to the rotary direction M5 of the agitator 5. As the agitator 5 is placed at the bottom of the wash-and-extraction tub 3, the water current generated in the lower part of the water stored in the wash-and-extraction tub 3 flows in the same direction as the rotation of the agitator 5. Therefore, the laundry moving on the water current contacts the inner wall of the wash-and-extraction tub 3 rotating in the opposite direction, and is washed (or rinsed) with a high performance. On the other hand, in the upper part away from the agitator 5 and along the inner wall of the wash-and-extraction tub 3, the water current flows not in the rotary direction M5 of the agitator 5, but in the rotary direction M6 of the wash-and-extraction tub 3. Therefore, the dirt-removing effect by the friction between the laundry and inner wall of the wash-and-extraction tub 3 is not adequate.
Thus, the present washing machine is constructed so that, in the process of rotating the

motor 14 clockwise and counterclockwise, the rotating direction of the motor 14 is reversed while the wash-and-extraction tub 3 is rotating due to inertia, or before the wash-and-extraction tub 3 completely halts. When the rotation of the motor 14 is reversed, the rotation of the wash-and extraction tub 3 is immediately reversed and opposes the movement of the laundry on the water current flowing due to inertia for a short time period. Fig. 12 shows the relation between the driving pattern of the motor 14 and the state of rotation of the agitator 5 and wash-and-extraction tub 3. As shown by time-chart (a) of Fig. 12, the motor 14 is driven by a periodical pattern, where each period consists of tl seconds of clockwise-ON, t2 seconds of OFF, tl seconds of counterclockwise-ON, and t2 seconds of OFF. When the motor 14 is turned off, the wash-and-extraction tub 3 continues rotating by inertia, and t2 is determined so that the motor 14 is turned on before the end of the inertial rotation. At the moment the motor 14 is turned on, the rotary direction of the wash-and-extraction tub 3 is reversed, whereas the water current caused by the inertial rotation cannot follow the reversal immediately. As a result, the direction of the water current and the rotary direction of the wash-and-extraction tub 3 become opposite to each other for a short period of time. Thus, the effect of removing dirt from the laundry placed at higher position is further improved.
The above-described embodiment is one example, and it is obvious that it can be changed or modified properly within the scope of the gist of the present invention.

WHAT IS CLAIMED IS:
1. A washing machine with a wash-and-extraction tub rotatably provided in an outer tub and an agitator rotatably provided on an inner bottom of the wash-and-extraction tub, characterized by comprising:
a) a hollow outer shaft rotating with the wash-and-extraction tub,
b) an inner shaft inserted in the outer shaft and rotating with the agitator,
c) a driving shaft provided coaxially with the outer shaft and inner shaft, and driven to rotate by a motor,
d) reduction means including:
an internal gear formed with or connected to the outer shaft, a sun gear formed with or connected to the driving shaft, and planetary gears connected to the inner shaft and engaging and rotating with the internal gear and the sun gear, and
e) driving switch means for connecting or disconnecting the driving shaft and the outer
shaft,
wherein, during a washing or rinsing process, the driving shaft is disconnected from the outer shaft by the driving switch means while the driving shaft and the outer shaft are connected via the sun gear, planetary gears and internal gear, so that the agitator is rotated in a preset direction, and, with the rotation of the agitator, the wash-and-extraction tub is rotated in a direction opposite to the preset direction by a reaction force of the planetary gears working on the internal gear.
2. The washing machine according to claim 1, characterized by not comprising a
brake mechanism for preventing the rotation of the outer shaft.
3. The washing machine according to claim 1, characterized by comprising a brake
mechanism for preventing the rotation of the outer shaft, wherein the brake is released for letting the outer shaft rotate freely during the washing or rinsing process, and the brake halts the outer shaft when the extraction process ends.

4. The washing machine according to claim 1 or 2, characterized in that:
the driving switch means comprises:
driving side engaging means rotated with the driving shaft, driven side engaging means rotated with the outer shaft and engageable or disengageable with the driving side engaging means,
a second motor,
a cam on a substantially circular disc rotated with the second motor, and shaft connecting means for connecting or disconnecting the driven side engaging means and the driving side engaging means corresponding to the rotation of the cam,
and the washing machine further comprises valve operation means for closing or opening a drain valve according to the rotation of the cam corresponding to a connection or disconnection of the driven side engaging means and the driving side engaging means.
5. The washing machine according to claim 4, characterized by:
ftirther comprising a loop transmission mechanism including: the motor,
a small pulley fixed on the motor shaft, a large pulley fixed on the driving shaft, and a belt looping around the small pulley and the large pulley; the driving side engaging means is constructed as an engaging hole formed in the large pulley;
the driven side engaging means is constructed as a movable body with the outer shaft inserted inside, slidable along the outer shaft, and having a claw on the face to the large pulley; and
the claw and the engaging hole are curved along a circle concentric with the driving shaft.
6. The washing machine according to claim 5, characterized in that the large pulley

is formed with two metal plates clamped together, and both circumferential ends of the engaging hole are wrap-clamped.
7. The washing machine according to one of claims 4-6, characterized in that, in
changing from the washing or rinsing process to the extraction process, the second motor is
operated to engage the driven side engaging means with the driving side engaging means, and
the second motor is controlled to rotate the driving shaft little by little.
8. The washing machine according to one of claims 4-7, characterized by further
I comprising:
detection means for detecting a preset rotary position of the cam, and determining means for determining whether a detection signal is obtained in the detection means within a preset time period from the time the second motor is started.
9. A washing machine substantially as herein described with
reference to the accompanying drawings.

Documents:

1054-mas-2000-abstract.pdf

1054-mas-2000-claims filed.pdf

1054-mas-2000-claims grand.pdf

1054-mas-2000-correspondnece-others.pdf

1054-mas-2000-correspondnece-po.pdf

1054-mas-2000-description(complete) filed.pdf

1054-mas-2000-description(complete) grand.pdf

1054-mas-2000-drawings.pdf

1054-mas-2000-form 1.pdf

1054-mas-2000-form 19.pdf

1054-mas-2000-form 26.pdf

1054-mas-2000-form 3.pdf

1054-mas-2000-form 5.pdf

1054-mas-2000-other documents.pdf

1054-mas-2000-verification documents.pdf

abs-1054-mas-2000.jpg

« Previous Patent

Next Patent »

Patent Number

208709

Indian Patent Application Number

1054/MAS/2000

PG Journal Number

35/2007

Publication Date

31-Aug-2007

Grant Date

07-Aug-2007

Date of Filing

06-Dec-2000

Name of Patentee

M/S. SANYO ELECTRIC CO.,LTD

Applicant Address

5-5 KEIHANHONDORI 2 CHOME, MORIGUCHI-SHI,OSAKA 570-8677.

Inventors:

#	Inventor's Name	Inventor's Address
1	YASUSHI ARAKI	5-5 KEIHANHONDORI 2 CHOME, MORIGUCHI-SHI,OSAKA 570-8677.

PCT International Classification Number

D 06 F 37/40

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	HLL-353993	1999-12-14	Japan