Title of Invention

BOBBIN-RAIL LIFTING AND LOWERING DEVICE IN A ROVING MACHINE

Abstract

An MRI coil system (34) comprises a local RF coil assembly (36) which includes one or more RF coil elements (38). An electronic circuit (88) is operatively connected to the RF coil elements (38), which electronic circuit (88) at least converts electrical signals into optical signals. A first connector (112) is in operative communication with the electronic circuit (88). A detachable cable (40) includes a second connector (120), which selectively mates with the first connector (112) and connects the coil elements (38) and the electronic circuit to an external device.

Full Text

BOBBIN-RAIL LIFTING AND LOWERING DEVICE IN A ROVING MACHINE BACKGROUND OF THE INVENTION The present invention relates to a device for lifting and lowering a bobbin rail in a roving machine and more particularly to a device for lifting and lowering the bobbin rail by a torque-controllable drive motor. A roving machine generally has a bobbin rail and a device for lifting and lowering the bobbin rail. The device includes a lifting and lowering mechanism such as a rack and a pinion gear driven by a motor for lifting and lowering the bobbin rail relative to the frame of the roving machine. Usually, the bobbin rail is lifted and lowered during roving operation of the machine, as well as during the operation of replacing a full bobbin with an empty bobbin. In the case of a roving machine wherein a spindle depends from the flyer of the roving machine, the bobbin rail needs to be lifted so as to allow the spindle to be inserted into an empty bobbin mounted on the bobbin rail. In this case, if the empty bobbin is not mounted in a proper position on the bobbin rail, the spindle interferes with the empty bobbin. If the bobbin rail is lifted with the spindle interfering with the empty bobbin, the lifting and lowering mechanism of the device may be damaged. For avoiding such damage of the lifting and lowering mechanism of the device, Japanese Patent Application Publication No. 60-65128 discloses a method for detecting abnormality of bobbin setting. According to the reference, a detector such as a photoelectric or ultrasonic sensor is provided so that light or ultrasonic wave is directed in the longitudinal direction of the bobbin rail along the side of the bobbin which is mounted on a bobbin wheel of the bobbin rail in a proper state. According to the method, the bobbin wheel is rotated for at least one turn after the bobbin is mounted on the bobbin wheel so that any bobbin which is mounted on the bobbin wheel in an inclined state is detected by the detector. However, the method of the above reference, according to which abnormality of the bobbin mounting on the bobbin wheel is detected before the bobbin is set to the spindle, requires the detector such as the photoelectric or ultrasonic sensor. If the detector fails to operate properly, the bobbin rail is lifted even when abnormality exists, so that the spindle and the bobbin may interfere with each other. Because the bobbin rail continues to be lifted even after the interference between the spindle and the bobbin, the lifting and lowering mechanism such as the rack and the pinion gear of the device is damaged unavoidably. In addition, in a roving machine in which the detector cannot be installed, it is definitely impossible to detect the abnormality of the device during lifting and lowering operation of the bobbin rail. The present invention is directed to a device for lifting and lowering a bobbin rail in a roving machine, wherein damage of a lifting and lowering mechanism of the device is avoided even if any abnormality such as the interference occurs during lifting and lowering operation of the bobbin rail. SUMMARY OF THE INVENTION In accordance with an aspect of the present invention, a bobbin-rail lifting and lowering device in a roving machine includes a bobbin rail, a lifting and lowering mechanism, a motor and a controller. The bobbin rail is lifted and lowered through the lifting and lowering mechanism. The motor lifts and lowers the bobbin rail. The controller controls operation of the motor. The bobbin-rail lifting and lowering device is characterized in that an upper torque limit and a lower torque limit are set as limits of output torque of the motor in the controller. The controller is operable to control the operation of the motor so that the upper torque limit is set as the limit of the output torque of the motor during roving operation of the roving machine. The controller is also operable to control the operation of the motor so that the lower torque limit is set as the limit of the output torque of the motor in lifting or lowering the bobbin rail during other than the roving operation. Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which: Fig. 1 is a partial schematic view showing a roving machine according to a first embodiment of the present invention; and Fig. 2 is a partial schematic view showing a roving machine according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe a device for lifting and lowering a bobbin rail in a roving machine (hereinafter referred to as a bobbin-rail lifting and lowering device) according to the first embodiment of the present invention with reference to Fig. 1. Referring to Fig. 1, the roving machine has three separate drive systems, i.e. the flyer drive system having a main motor 14 for drafting and flyer operations, the bobbin drive system having a wind-up motor 28 for rotating a bobbin B and the lifting and lowering system having a motor 36 for lifting and lowering a bobbin rail 22. As shown in Fig. 1, the flyer drive system further has a front roller 11 which is driven to rotate by the main motor 14 through a drive belt and a gear train (neither being shown). The drive belt and the gear train are provided between a driven gear 13 which is mounted on a rotary shaft 12 at one end thereof and the driving shaft 15 of the main motor 14. The operation of the main motor 14 ^s controlled through an inverter 16. The flyer 17 of the roving machine has a spindle 17C and a driven gear 19 is fixedly mounted on the spindle 17C above the flyer 17 for rotation with the spindle 17C. The driven gear 19 engages with a driving gear 21 which has at the axis thereof a rotary shaft 20. The rotation of the driving shaft 15 of the main motor 14 is transmitted through a drive belt (not shown) to the rotary shaft 20 on which the driving gear 21 is fixed, so that the driven gear 19 is driven to rotate with the flyer 17. A bobbin rail 22 is located below the flyer 17, having therein a bobbin wheel 23 on which the bobbin B is mounted. A driven gear 24 is fixed to the bobbin wheel 23 and engaged with a driving gear 25 having a rotary shaft 26. The rotary shaft 26 is operatively connected to the main motor 14 and the wind-up motor 28 through a differential gear mechanism 29, so that a combined rotation of the main motor 14 and the wind-up motor 28 is transmitted to the rotary shaft 26 of the driving gear 25 through the differential gear mechanism 29. The operation of the wind-up motor 28 is controlled through an inverter 27 such that the rotational speed of the bobbin B mounted on the bobbin wheel 23 is decreased with an increase of the wound diameter of the bobbin B. The roving machine is also so controlled that, when the wind-up motor 28 is stopped or in the state where the differential gear mechanism 29 receives no input from the wind-up motor 28, the bobbin B is rotated at the same speed as the flyer 17. The bobbin rail 22 is lifted and lowered by the motor 36 of the lifting and lowering system through a lifting and lowering mechanism having a lifter rack 30, a pinion gear 31 and a rotary shaft 32. The lifter rack 30 is fixed to the bobbin rail 22 and engages with the pinion gear 31 whose rotary shaft 32 is operatively connected to the driving shaft 34 of the motor 36, so that the rotation of the driving shaft 34 is transmitted to the rotary shaft 32 of the pinion gear 31. The operation of the motor 36 serving as a servomotor is controlled through a servo-amplifier 35. The rotational direction of the rotary shaft 32 is changed in accordance with the switching the motor 36 between the forward and reverse rotations, and the lifting and lowering direction of the bobbin rail 22 is changed, accordingly. A rotary encoder 37 is connected to one end of the rotary shaft 32 for detecting the direction and amount of movement of the bobbin rail 22. A gear train may be interposed between the motor 36 and the driving shaft 34. Alternatively the driving shaft 34 may be connected to the motor 36 for rotation therewith. The rotary encoder 37 may be replaced by any suitable devices such as a resolves or an encoder attached to the motor 36. A sensor 38 is located adjacent to the driven gear 13 which rotates with the front roller 11 and detects the rotational amount of the front roller 11. Another sensor 39 is located adjacent to the driven gear 19 for detecting the rotational speed of the flyer 17. Roving R let off from the front roller 11 passes from a flyer top 17A of the flyer 17 through a guide funnel to a flyer leg 17B of the flyer 17. Then, the roving R Is led to the bobbin B through a presser 40 extending from the bottom of the flyer leg 178. The presser 40 of the present embodiment is of such a tincture that a guide hole 42 and a guide slot 43 which guides the roving R into the guide hole 42 are formed in a presser paddle 41. The main motor 14 and the wind-up motor 28 are controlled by a controller 45 through the inverters 16, 27, respectively, and the motor 36 by the controller 45 through the servo-amplifier 35. The controller 45 has a central processing unit (CPU) 46, a program memory 47, a working memory 48, an input interface 49, an output interface 50 and an input device 51. The CPU 46 is operable to execute predetermined programs stored in the program memory 47 for controlling the operation of the main motor 14 and the wind-up motor 28 through the output interface 50 and the inverters 16, 27, respectively. Further, the CPU 46 controls the operation of the motor 36 through the output interface 50 and the servo-amplifier 35. The input device 51 through which roving conditions such as roving weight (grain), the kind of fiber and the number of twists and the like are inputted is incorporated in the controller 45 in the form of a keyboard. Output signals from the rotary encoder 37 and the sensors 38, 39 are transmitted to the CPU 46 through the input interface 49. The program memory 47 is provided by a read-only memory (ROM) which stores therein the above programs and various kinds of data necessary for the execution of the programs. The programs include a control program for controlling the operation of the main motor 14, the wind-up motor 28 and the motor 36 during winding operation of the bobbin B, and a control program for doffing operation. The various kinds of data include roving machine operating data relating to the moving speed of the bobbin rail 22, the wound diameter of the roving R and the rotational speed of the bobbin wheel 23 during roving operation of the roving machine. The working memory 48 is provided by a random access memory (RAM) which temporarily stores therein data inputted through the input device 51, result of arithmetic operation executed in the CPU 46 and the like. The working memory 48 has a backup power supply (not shown). The control program for doffing operation performed while the roving machine is at a stop includes a program for process of stopping operation of the roving machine and a program for process of lowering the bobbin rail 22 to a doffing position after stopping the operation of the roving machine. An upper torque limit and a lower torque limit are set as limits of output torque of the motor 36 in the control program for controlling the operation of the motor 36. During the roving operation of the roving machine (or from the beginning to the end of the bobbin winding operation), the upper torque limit is set as the output torque limit of the motor 36. The upper torque limit is set so as to correspond to the weight of the full bobbin B and/or to correspond to an impact load produced when the movement of the bobbin rail 22 is reversed. The lower torque limit is set lower than the upper torque limit. In lifting or lowering the bobbin rail 22 during operation of the roving machine other than the roving operation, the lower torque limit is set as the output torque limit of the motor 36. The following will describe the operation of the roving machine. Prior to the operation of the roving machine, the roving conditions such as roving weight (grain), the kind of fiber and the number of twists and the like are inputted through the input device 51. As the roving machine is started, the main motor 14, the wind-up motor 28 and the motor 36 are started synchronously at their respective predetermined speeds based on the roving conditions. As the driving shaft 15 of the main motor 14 is rotated, the front roller 11 and the flyer 17 are rotated at their respective constant speeds with a predetermined speed ratio. The rotational speed of the driving shaft 15 of the main motor 14 and the rotational speed of the output shaft of the wind-up motor 28 are combined by the differential gear mechanism 29, and the speed of the bobbin wheel 23 is changed in accordance with the current wound diameter of the roving R of the bobbin B. The bobbin rail 22 is moved up and down in accordance with the switching the motor 36 between the forward and reverse rotations. While the bobbin rail 22 is being thus lifted and lowered, the roving R let off from the front roller 11 is wound around the bobbin B. During the roving operation of the roving machine, the CPU 46 performs counting in accordance with the output signals from the sensor 38. When the count of the CPU 46 reaches a value corresponding to roving length figured out from a predetermined roving weight, the CPU 46 recognizes that the bobbin B becomes full and then starts the control program of stopping for doffing operation. After the operation of the roving machine is stopped and then the bobbin rail 22 is lowered to the doffing position, the roving R is cut off. The following will describe the replacing of the full bobbin by a new empty bobbin B. In doffing the full bobbin B, the bobbin rail 22 is located at its lowermost position. After the full bobbin B is doffed from the bobbin rail 22 and then the bobbin rail 22 is lifted, an empty bobbin B is mounted onto the bobbin wheel 23 of the bobbin rail 22. In the present embodiment, such doffing operation and bobbin mounting operation are manually performed. After the empty bobbin B is mounted onto the bobbin wheel 23 of the bobbin rail 22, the bobbin rail 22 is further lifted for inserting the spindle 17C into the empty bobbin B. In this case, the lower torque limit is set as the output torque limit of the motor 36. Because the interference between the spindle 17C and the empty bobbin B occurs locally in a longitudinal direction of the bobbin rail 22, concentrated load acts on the lifter rack 30, the pinion gear 31 and the like corresponding to the position of the bobbin rail 22 where the interference occurs. Even if the output torque of the wind-up motor 28 is lower than the upper torque limit which is set as the limit of the output torque of the wind-up motor 28 during the roving operation, the lifter rack 30, the pinion gear 31 and the like may be damaged. For this reason, the lower toque limit is set as the output torque limit of the motor 36 during doffing operation. In the present embodiment, the lower torque limit is about 33 % of the upper torque limit. If the empty bobbin B is not mounted onto the bobbin wheel 23 of the bobbin rail 22 in a proper position, but in an inclined position, the spindle 17C interferes with the empty bobbin B when the bobbin rail 22 is lifted by driving the motor 36. When the motor 36 continues to be driven even after the interference between the spindle 17C and the empty bobbin B, torque of the motor 36 is increased because of the interference. In this case, because the output torque limit is set as the lower torque limit of the motor 36, the motor 36 slips when the torque of the lower torque limit is applied to the motor 36. The driving shaft 34 is not rotated any more and the rotary shaft 32 is not rotated either, accordingly. Therefore, the lifting motion of the bobbin rail 22 is stopped. Detailed description for the above operation will be given. The controller 45 is operable to read with time pulse signals transmitted from the rotary encoder 37 to the controller 45 and pulse signals for position command received by the servo-amplifier 35 from the controller 45. The accumulation of the pulse signals transmitted from the rotary encoder 37 to the controller 45 is indicative of the lifted or lowered position of the bobbin rail 22, and the number of pulse signals per unit time is indicative of the speed of lifting or lowering of the bobbin rail 22. A decrease of the number of pulse signals per unit time transmitted from the rotary encoder 37 to the controller 45 is indicative of a decrease of the lifting or lowering speed of the bobbin rail 22. When no change of the accumulation of the pulse signals occurs, the position of the bobbin rail 22 remains unchanged, which means that the bobbin rail 22 remains at a stop. When the number of pulse signals transmitted from the rotary encoder 37 to the controller 45 decreases while a certain number of pulse signals for position command is transmitted from the controller 45 to the servo-amplifier 35, the difference in number between these different kinds of pulse signals is increased. This increase means an increasing difference between the preset or commanded target position (or speed) and the actual lifted or lowered position (or speed). If this increasing difference between the preset position (or speed) and the actual position (or speed) exceeds a predetermined position value (or speed value), the motor 36 slips and, therefore, the driving shaft 34 is not rotated any more after the output torque of the motor 36 reaches the lower torque limit. Thus, the controller 45 recognizes that the movement of the bobbin rail 22 is stopped for any abnormality. The bobbin-rail lifting and lowering device of the first embodiment has the following advantageous effects. (1) In lifting or lowering the bobbin rail 22 during the operation of the roving machine other than its roving operation, the lower torque limit is set as the output torque limit of the motor 36. Therefore, if the spindle 17C interferes with the bobbin B during the bobbin changing operation and the output torque of the motor 36 is increased to reach the lower torque limit, the motor 36 slips because the motor 36 cannot output torque larger than the lower torque limit. Thus, because the movement of the bobbin rail 22 is prevented when the output torque of the motor 36 is increased to reach the lower torque limit, damage of the lifting and lowering mechanism is avoided. (2) When the difference between the actual lifted or lowered position (or speed) and the preset position (or speed) of the bobbin rail 22 exceeds the predetermined value in lifting or lowering the bobbin rail 22 during other than its roving operation, the movement of the bobbin rail 22 is stopped. ■ - (3) The torque at the lower torque limit is set to be capable of at least lifting the bobbin rail 22 on which the empty bobbin B is mounted and also capable of avoiding the damage of the lifting and lowering mechanism when the movement of the bobbin rail 22 is stopped for any abnormality. Therefore, the bobbin rail 22 on which the empty bobbin B is mounted is lifted and lowered while the lifting and lowering mechanism is not damaged even if the motor 36 produces the output torque at the lower torque limit. The following will describe a bobbin-rail lifting and lowering device in a roving machine according to the second embodiment of the present invention with reference to Fig. 2. As is obvious from comparison of Fig. 1 and Fig. 2, the second embodiment of Fig. 2 differs from the first embodiment in the structure of the lifting and lowering system of the three drive systems of the roving machine. For the sake of convenience of explanation, therefore, like or same parts or elements will be designated by the same reference numerals as those which are used in the first embodiment, and the description thereof will be omitted. In the second embodiment, the lifting and lowering motor 54 is provided by an induction motor and its operation is controlled by the controller 45 through an inverter 55. The inverter 55 is operable to vector-control the motor 54. Specifically, the inverter 55 estimates the torque and the rotational speed of the motor 54 based on the magnitude and phase of electric current flowing in each winding of the motor 54 and then changes the voltage and frequency of the motor 54 based on the estimated torque and rotational speed for controlling to obtain the target torque and rotational speed of the motor 54. The inverter 55 controls the motor 54 such that the value of electric current corresponding to the preset lower torque limit is not exceeded. The bobbin-rail lifting and lowering device of the second embodiment has the same advantageous effects as those (1) and (3) of the first embodiment. In addition, because of the vector controlling of the inverter 55, the second embodiment dispenses with the encoder 37, thereby to simplify the elements of the control system for the motor 54. The present invention is not limited to the above-described embodiments, but may be variously modified within the scope of the invention, as exemplified below. Although in the above-described embodiments in lifting the bobbin rail 22 during bobbin changing operation, the lower torque limit is set as the output torque limit of the lifting and lowering motor, the lower torque limit may be set not only in lifting the bobbin rail 22 but also in lowering the bobbin rail 22. In this case, the controller 45 can recognize abnormality due to any interference of the bobbin rail 22 with any other objects while the bobbin rail 22 is lowered during other than its roving operation. In the above-described embodiments, in lifting or lowering the bobbin rail 22 during other than its roving operation, the lower torque limit is set as the output torque limit of the lifting and lowering motor for the controller 45 to recognize an abnormal stop of the bobbin rail 22. However, a torque sensor may be provided for detecting the output torque of the lifting and lowering motor so that the controller 45 recognizes any abnormality when the detected torque value reaches the lower torque limit. Alternatively, it may be so arranged that the controller 45 recognizes the abnormality of the movement of the bobbin rail 22 when the rate of increase or decrease of the torque is rapidly changed to exceed a predetermined rate of change. Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein but may be modified within the scope of the appended claims. What is claimed is: 1. A bobbin-rail lifting and lowering device in a roving machine, comprising: a bobbin rail; a lifting and lowering mechanism through which the bobbin rail is lifted and lowered; a motor for lifting and lowering the bobbin rail; and a controller for controlling operation of the motor; characterized in that an upper torque limit and a lower torque limit are set as limits of output torque of the motor in the controller, wherein the controller is operable to control the operation of the motor so that the upper torque limit is set as the limit of the output torque of the motor during roving operation of the roving machine and that the lower torque limit is set as the limit of the output torque of the motor in lifting or lowering the bobbin rail during other than the roving operation. 2. The bobbin-rail lifting and lowering device according to claim 1, wherein torque at the lower torque limit is set to be capable of at least lifting the bobbin rail on which an empty bobbin is mounted and also capable of avoiding damage of the lifting and lowering mechanism when movement of the bobbin rail is stopped for abnormality. 3. The bobbin-rail lifting and lowering device according to claim 1 or 2, wherein lifting or lowering the bobbin rail during other than the roving operation is lifting the bobbin rail during bobbin changing operation. 4. The bobbin-rail lifting and lowering device according to any one of claims 1 through 3, wherein when difference between an actual lifted or lowered position and a preset position of the bobbin rail exceeds a predetermined position value in lifting or lowering the bobbin rail during other than the roving operation, movement of the bobbin rail is stopped. 5. The bobbin-rail lifting and lowering device according to any one of claims 1 through 3, wherein when difference between an actual lifting or lowering speed and a preset speed of the bobbin rail exceeds a predetermined speed value in lifting or lowering the bobbin rail during other than the roving operation, movement of the bobbin rail is stopped. 6. The bobbin-rail lifting and lowering device according to any one of claims 1 through 5, wherein a servo-amplifier is provided, through which the operation of the motor is controlled by the controller. 7. The bobbin-rail lifting and lowering device according to claim 6, wherein a rotary encoder is connected to the lifting and lowering mechanism for detecting direction and amount of movement of the bobbin rail, wherein the controller Is operable to read with time pulse signals transmitted from the rotary encoder to the controller and pulse signals for position command received by the servo-amplifier from the controller. 8. The bobbin-rail lifting and lowering device according to any one of claims 1 through 7, wherein the lower torque limit is about 33 % of the upper torque limit. 9. The bobbin-rail lifting and lowering device according to any one of claims 1 through 3, wherein an inverter is provided, through which the operation of the motor is controlled by the controller, wherein the inverter is operable to vector-control the motor. 10. The bobbin-rail lifting and lowering device according to claim 1, wherein a torque sensor is provided for detecting the output torque of the motor.

Documents:

1118-CHE-2008 AMENDED PAGES OF SPECIFICATION 04-03-2013.pdf

1118-CHE-2008 AMENDED CLAIMS 04-03-2013.pdf

1118-CHE-2008 CORRESPONDENCE OTHERS 04-01-2013.pdf

1118-che-2008 abstract.pdf

1118-che-2008 claims.pdf

1118-che-2008 correrspondences-others.pdf

1118-che-2008 description (complete).pdf

1118-che-2008 drawings.pdf

1118-CHE-2008 EXAMINATION REPORT REPLY RECEIVED 04-03-2013.pdf

1118-che-2008 form-1.pdf

1118-che-2008 form-18.pdf

1118-che-2008 form-26.pdf

1118-CHE-2008 FORM-3 04-03-2013.pdf

1118-che-2008 form-3.pdf

1118-che-2008 form-5.pdf