Title of Invention

"AN ENERGY STORING MECHANISM HAVING A SPRING SYSTEM FOR A CIRCUIT BREAKER"

Abstract An energy storing mechanism having a spring system for a circuit breaker, wherein energy stored in a breaking spring (89) is discharged to effect a circuit opening operation to a contact, and energy is stored in the breaking spring, by means of a cam shaft (8) and a cam (13) fixed to it via a driving means which is driven by a motor, is characterized by: a gear wheel (9) fixed to the cam shaft, and a pinion (15) meshing with the gear wheel; a clutch driving element (16) provided on the same axis as the pinion, which constitutes a clutch together with the pinion, and is driven by an electric motor (17); and an end-face (9a) cam provided at a side surface of the gear wheel and adapted to press the clutch driving element at or near a stationary position of the gear wheel to release the connection between the pinion and the clutch driving element, wherein the gear wheel (9) has a guiding circular plate (9b) fixed to a side surface thereof, and the pinion (15) has a groove (15d) fitted to the guiding circular plate so as to maintain a relative position in axial direction of the gear wheel and the pinion to be constant.
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FIELD OF THE INVENTION
The present invention relates to an energy storing mechanism having a spring system for a circuit breaker.
BACKGROUND OF THE INVENTION
There is a requirement by a standard for the operation mechanism of a circuit breaker to have such a construction that the opening and closing of a circuit can be performed in succession without a delay. In order to meet the requirement of such standard, there is a conventional technique wherein a circuit closing operation is performed by the aid of an electric motor immediately after a circuit opening operation has been performed by using a mechanical energy stored in an energy storing mechanism (a spring is generally used therein) so that energy is stored in the energy storing mechanism for a successive circuit opening operation.
As a conventional mechanism for operating a circuit breaker, the construction and operation of the operation mechanism as disclosed in Indian Patent Application No. 1782/MAS/96 [Japanese unexamined Patent Publication JP-A-9-106741] will be described.

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A lever linked with a movable contact is fixed to a main shaft to which a rotating force is applied clockwise by a breaking spring, and is held in a closing position by a tripping latch. When the tripping latch is turned counterclockwise by a tripping trigger mechanism, the fever is turned counterclockwise to open the movable contact.
A gear wheel is fixed to a cam shaft so as to rotate along with the cam shaft. A connecting pin is provided on a side surface of the gear wheel. A closing lever is fixed to a closing main shaft to which a rotating force is applied counterclockwise by a closing spring. A link connects the pin to an end portion of the closing lever. A lever crank mechanism (hereinafter referred to as "mechanism") is formed by a crank formed between the center of the gear wheel and the connecting pin ; the link as a connecting rod ; and the closing lever as a driver.
The gear wheel is kept by a closing latch at its closing awaiting position which is slightly shifted clockwise from a change point (an upper dead point) of the mechanism. When the closing latch is turned counterclockwise by the actuation of a closing trigger mechanism, the closing lever is turned counterclockwise and the gear wheel is turned clockwise, respectively, by the mechanical energy stored in the closing spring. A cam fixed to the cam shaft together with the gear wheel is rotated so that the lever in its breaking position is returned to its closing position against the rotating force of the breaking spring to thereby close the movable contact.

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At the same time, a pinion meshed with the gear wheel is rotated counterclockwise through a clutch driving means by the aid of an electric motor. Then, the gear wheel is rotated clockwise against the rotating force of the closing spring so as to return to the initial state.
The above-mentioned elements are assembled on a frame to form an operating mechanism. Among these elements, elements for transmitting a force from the electric motor to the closing spring via the clutch driving element,
the pinion, the gear wheel, the link, the closing lever and so on, constitute an energy storing mechanism.
A clutch shaft and the rotating shaft of the electric motor are disposed in parallel to the cam shaft. These three shafts are connected in the form of a series of gear wheels comprising the gear wheel, the pinion formed in an end of the clutch shaft, the clutch driving element having a gear element at its outer circumference and a gear formed in an end of the rotating shaft of the electric motor. The pinion and the clutch driving element constitute a clutch.
The cam shaft extends through frame walls and is supported by a pair of bearings at the frame walls. A cam is firmly fitted to the camshaft at an intermediate position between the frame walls and the gear wheel on which a projection (an end-face cam) is provided is firmly fitted to one of the free ends whereby the cam

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shaft and the cam are rotated together along with the rotation of the gear wheel. The cam shaft is prevented from movement in the axial direction beyond a play in the bearings.
The clutch shaft also extends through the frame walls and is supported by a pair of bearings at the frame walls so as to be rotatable. The pinion is provided at the end of the clutch shaft at the side of the frame wall. The clutch shaft is allowed to move to some extent in the axial direction.
The clutch shaft is provided with an inner wheel at its outer circumference in the end portion at the side where the gear wheel meshes with the pinion. Further, the clutch shaft is provided with a hollow portion at a center portion thereof having a cylindrical wall surface which is concentric with the inner wheel.
The pinion comprises a toothed wheel portion meshing with the gear wheel and a shaft portion integrally formed therewith. The shaft portion is fitted rotatably in the hollow portion of the cam shaft through a stopper member.
The inner wheel is fitted to the clutch shaft so as to be movable in the axial direction together with the clutch driving element. Radial grooves are formed in an end portion (the end opposing the pinion) to mesh with the toothed wheel portion of the pinion

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The traveling distance of the dutch driving element is regulated by the height of the projection provided on the gear wheel so that the meshing engagement between the pinion and the radial grooves of the inner wheel is disconnected in the state that the clutch driving element is pressed by the projection and is moved toward the frame wall. While the gear wheel is rotated clockwise to an appropriate location from a position which is slightly shifted clockwise from the change point of the mechanism to the closing awaiting position, the projection provided on the gear wheel presses the clutch driving element toward the frame wall to move the dutch shaft by a predetermined distance whereby the meshing engagement between the pinion and the radial grooves of the inner wheel is disconnected.
The clutch driving element is composed of the inner wheel, the outer wheel and a one-way clutch provided between the inner wheel and the outer wheel wherein the inner wheel is fitted to the clutch shaft so as to be rotatable and movable in the axial direction. The outer surface of the inner wheel is fitted to the one-way clutch.
The outer wheel is meshed at an outer peripheral toothed wheel portion thereof with a toothed wheel portion formed in the shaft end of the electric motor and fitted at the inner diametrical surface thereof with the one-way clutch so that it is mutually rotatable with respect to the inner wheel while not causing a relative

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movement in the axial direction. The one-way clutch is adapted such that it transmits a torque from the outer wheel to the inner wheel only when the outer wheel
/as seen from the side of the pinion
is rotated counterclockwise with respect to the inner wheel/ The tooth width of the toothed wheel portion formed in the end of the shaft of the electric motor is formed so as to always mesh with the clutch driving element even when it is displaced by the projection.
A clutch spring is disposed between the frame wall and the clutch driving element so as to press continually the clutch driving element towards the pinion.
The operation of the mechanism will be described. The operation for storing mechanical energy in the closing spring after the closing of the movable contact is as follows :
The electric motor is rotated clockwise and the dutch driving element is rotated counterclockwise by the toothed wheel portion formed at the shaft end of the motor. When the closing spring has released the mechanical energy, the projection formed on a side face of the gear wheel is at a position spaced apart from the clutch driving element. Accordingly, the clutch driving element is pressed by the clutch spring so that the pinion and the radial grooves formed in the end portion of the inner wheel mesh with each other whereby the pinion can be driven by the electric motor through the clutch driving element.

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When the gear wheel is rotated and has slightly passed clockwise the change point of the mechanism, the projection presses the clutch driving element to move it toward the frame wall. As a result, the linkage between the pinion and the clutch driving element is disconnected. At this moment, the electric motor does not drive the pinion.
After the disengagement of linkage between the pinion and the clutch driving element, the gear wheel is further rotated clockwise by a small amount by the force of the closing spring, and is stopped at its closing awaiting position by the closing latch.
Since the linkage between the clutch driving element and the pinion is disconnected just before the point where the mechanism reaches the closing waiting position, a force due to the output torque of the electric motor is not applied to the closing latch even if the electric motor rotates due to inertia after the stopping of the gear wheel.
Since the projection is brought into contact with a gentle slope formed in the outer wheel, there is a fair fluctuation, between the position of the projection in which the projection begins to contact the outer wheel and the position in which it has pushed the outer wheel, depending on the position of a top portion of the projection (a vertical position or a height) which is brought to contact with the outer wheel.

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The position of the top portion of the projection varies not only depending on the height of the projection but also the position of the gear wheel in the axial direction, namely, a shift of the cam shaft in the axial direction. Further, the position of the outer wheel is influenced by the position of the pinion in the axial direction (i.e., a position of the clutch shaft movable in its axial direction). Accordingly, it is necessary that the above-mentioned fluctuation is absorbed by adjusting the height of the projection so as to obtain correct operational positions of the clutch. !n the conventional, technique there is a problem that the adjustment is difficult since a slight difference of height of the projection causes a substantial change in the angular position of the gear wheel, and the adjustment requires a lot of labor. Specifically, in the conventional energy storing mechanism adapted to disconnect the clutch by pressing the outer wheel by means of the projection, a fluctuation is produced in angular position of the gear wheel at the time of disconnection (or connection) of the clutch due to fluctuation in the relative distance between the gear wheel and the outer wheel and , due to fluctuation in the height of the projection. This results in reduction in the performance of a circuit breaker installing the energy storing device therein. Accordingly, it is insufficient to merely adjust correctly the height of the projection to a regulated dimension, and it is necessary to finely adjust the height at an actual working site.

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SUMMARY OF THE INVENTION
It is an object of the present invention to provide an energy storing mechanism which eliminates fluctuation in angular position of the gear wheel at the time of the connection and disconnection of the clutch when the height of the projection is once met with a regulated dimension, and which does not require adjustments of the height of the projection at an actual working site.
Accordingly the present invention provides an energy storing mechanism having a spring system for a circuit breaker, wherein energy stored in a breaking spring is discharged to effect a circuit opening operation to a contact, and energy is stored in the breaking spring, by means of a cam shaft and a cam fixed to the cam shaft via a driving means which is driven by a motor, said energy storing mechanism being characterized by : a gear wheel fixed to a camshaft; a pinion meshing with said gear wheel; a clutch driving element provided on the same axis as said pinion, which constitutes a clutch together with said pinion, and is driven by an electric motor; and an end-face cam provided at a side surface of the gear wheel and adapted to press the clutch driving element at or near a stationary position of the gear wheef to release the connection between the pinion and the clutch driving element, wherein said gear wheel has a guiding circular plate fixed to a side surface of the gear wheel, and said pinion has a groove fitted to the guiding circular plate so as to maintain a relative position in axial direction of the gear wheel and the pinion to be constant.

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In the above-mentioned invention, a circular arc plate may be provided instead of the guiding circular plate, at the periphery of the gear wheel in the vicinity of the position where the end-face cam is provided.
Further, in accordance with an embodiment of the present invention, there is provided an energy storing mechanism having a spring system for a circuit breaker, wherein energy stored in a breaking spring is discharged to effect a circuit opening operation to a contact, and energy is stored in the breaking spring, by means of a cam shaft and a cam fixed to the cam shaft via a driving means which is driven by a motor, said energy storing mechanism being characterized by : a gear wheel fixed to a cam shaft; a pinion meshing with said gear wheel; a clutch driving element provided on the same axis as said pinion, which constitutes a clutch together with said pinion, and is driven by an electric motor; and an end-face cam provided at a side surface of said gear wheel and adapted to press the clutch driving element at or near a stationary position of the gear wheel to release the connection between the pinion and the clutch driving element, wherein said pinion has a guiding circular plate fixed to a side surface of the gear wheel, and the gear wheel has a groove fitted to the guiding circular plate so as to maintain a relative position in axial direction of the gear wheel and the pinion to be constant.
Further, in accordance with the present invention, there is provided an energy storing mechanism having a spring system for a circuit breaker wherein energy stored in a breaking spring is discharged to effect a circuit opening operation to a contact, and energy is stored in the breaking spring, by means of a cam shaft and a cam fixed to the cam shaft via a driving means which is driven by a motor, said energy storing

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mechanism being characterized by : a gear wheel fixed to a cam shaft; a pinion meshing with said gear wheel; a clutch driving element provided on the same axis as said pinion, which constitutes a clutch together with said pinion, and is driven by an electric motor; and an end-face cam provided at a side surface of said gear wheel and adapted to press the clutch driving element at or near a stationary position of the gear wheel to release the connection between the pinion and the clutch driving element, wherein said pinion has two guiding circular plates fixed to an intermediate position between the free end and the tooth surface of the pinion and the gear wheel is fitted to the space between the two guiding circular plates so as to maintain a relative position in axial direction of the gear wheel and the pinion to be constant.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Figure 1 is a front view of an operation means having an energy storing mechanism for a circuit breaker according to a first embodiment of the present invention;
Figure 2 is a cross-sectional view taken along a line A-A in Figure 1 ;
Figure 3 is a diagram showing a portion in Figure 2 ;
Figure 4 is a diagram showing a modified form of the embodiment shown in Figure 1 ;

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Figures 5a, 5b are a front view and a side view of a part used for the energy storing mechanism according to a second embodiment of the present invention ;
Figure 6 is a diagram showing a portion in the energy storing mechanism according to a third embodiment of the present invention ;
Figure 7 is a diagram showing a portion in the energy storing mechanism according to a fourth embodiment of the present invention ;
Figure 8 is a front view showing a conventional operation means for a circuit breaker which is in a circuit closing state ;
Figure 9 is a cross-sectional view along line A-A in Fig. 8, showing a portion in the operation means of Figure 8 ;
Figure 10 is an enlarged diagram showing a portion shown in Figure 9 ;
Figure 11 is a perspective view showing parts shown in Figure 10 ; and
Figures 12a, 12b are diagrams showing the operations of the operation means shown in Figure 10. Description of Conventionsl Mechanism :
In Figs. 9 to 12b, expressions showing directions of rotation are used on the basis of Fig. 8.
A lever 2 linked with a movable contact 100 (expressed by a sign of circuit in Figure 8) is fixed to a main shaft 3 to which a rotating force is applied clockwise by a breaking spring 87 (expressed by a sign of spring), and is held in a closing position by a tripping latch 4. When the tripping latch 4 is turned counterclockwise by a tripping trigger mechanism 5, the lever 2 is turned counterclockwise to open the movable contact 100.

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A gear wheel 9 is fixed to a cam shaft 8 so as to rotate along with the cam shaft 8. A connecting pin 88 is provided on a side surface of the gear wheel 9. A closing lever 7 is fixed to a closing main shaft 6 to which a rotating force is applied counterclockwise by a closing spring (expressed by a sign of spring). A link 10 is provided to link the connecting pin 88 to an end portion of the closing lever 7. A lever crank mechanism (hereinafter, simply referred to as "mechanism") is formed by a crank formed between the center of the gear wheel 9 and the connecting pin 88 ; the link 10 as a connecting rod ; and the closing lever 7 as a driver.
The gear wheel 9 is kept by a dosing latch 11 at its dosing awaiting position which is slightly shifted clockwise from a change point (an upper dead point) of the mechanism (i.e., a state shown in Figure 8). When the closing latch 11 is turned counterclockwise by the actuation of a closing trigger mechanism 12, the closing lever 7 is turned counterclockwise and the gear wheel 9 is turned clockwise, respectively, by the mechanical energy stored in the closing spring 89. A cam 13 fixed to the cam shaft 8 together with the gear wheel 9 is rotated so that the lever 2 in its breaking position is returned to its closing position against the rotating force of the breaking spring 87 to thereby close the movable contact 100.
At the same time, a pinion 15 meshed with the gear wheel 9 is rotated counterclockwise through a clutch driving means 16 by the aid of an electric motor 17. Then, the gear wheel 9 is rotated clockwise against the rotating force of the closing spring 89 so as to return to the state shown in Figure 8.

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The above-mentioned elements are assembled on a frame 1 to form an operating mechanism. Among these elements, elements for transmitting a force from the electric motor 17 to the closing spring 89 via the clutch driving element 16,
the pinion 15, the gear wheel 9, the link 10, the closing lever 7 and so on, constitute an energy storing mechanism.
A clutch shaft 14 and the rotating shaft of the electric motor 17 are disposed in parallel to the cam shaft 8. These three shafts are connected in the form of a series of gearwheels comprising the gear wheel 9, the pinion 15 formed in an end of the clutch shaft 14, the clutch driving element 16 having a gear element (an outer ring 19) at its outer circumference and a gear formed in an end of the rotating shaft of the electric motor 17. The pinion 15 and the clutch driving element 16 constitute a clutch.
The cam shaft 8 extends through frame walls 1a, 1b and is supported by a pair of bearings at the frame walls. A cam 13 is firmly fitted to the cam shaft 8 at an intermediate position between the frame walls 1a, 1b, and the gear wheel 9 on which a projection (an end-face cam) 9a is provided is firmly fitted to one of the free ends (which is at the side of the frame wall 1 a) whereby the cam shaft 8 and the cam 13 are rotated in one-piece along with the rotation of the gear wheel 9. The cam shaft 8 is prevented from movement in the axial direction beyond a play in the bearings.
The clutch shaft 14 also extends through the frame walls 1a, 1b and is supported by a pair of bearings at the frame walls 1a, 1b so as to be rotatable. The pinion 15 is provided at the end of the clutch shaft 14 at the side of the frame wall 1a. The clutch shaft 14 is allowed to move to some extent in the axial direction.

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The clutch shaft 14 is provided with an inner wheel 18 at its outer circumference in the end portion at the side where the gear wheel 9 meshes with the pinion 15. Further, the clutch shaft 14 is provided with a hollow portion 14b at a center portion thereof having a cylindrical wall surface which is concentric with the inner wheel 18.
The pinion 15 comprises a toothed wheel portion 15a meshing with the gear wheel 9 and a shaft portion 15b integrally formed therewith. The shaft portion 15b is fitted rotatably in the hollow portion 14b of the cam shaft 8 through a stopper member 14c.
The inner wheel 18 is fitted to the clutch shaft 14 so as to be movable in the axial direction together with the clutch driving element 16. Radial grooves 18a are formed in an end portion (the end opposing the pinion 15) to mesh with the toothed wheel portion 15 of the pinion 15.
Figure 11 is a perspective view of the pinion 15 and the inner wheel 18 to clarify the structure of the inner wheel 18.
The traveling distance of the dutch driving element 16 is regulated by the height of the projection 9a provided on the gear wheel 9 so that the meshing engagement between the pinion 15 and the radial grooves 18a of the inner wheel 18 is disconnected in the state that the clutch driving element 16 is pressed by the projection 9a and is moved toward the frame wall. While the gear wheel 9 is rotated clockwise to an appropriate location from a position which is slightly shifted clockwise from the change point of the mechanism to the closing awaiting position, the projection

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9a provided on the gear wheel 9 presses the clutch driving element 16 toward the frame wall to move the clutch shaft 14 by a predetermined distance whereby the meshing engagement between the pinion 15 and the radial grooves 18a of the inner wheel 18 is disconnected.
The clutch driving element 16 is composed of the inner wheel 18, the outer wheel 19 and a one-way clutch 20 provided between the inner wheel 18 and the outer wheel 19 wherein the inner wheel 18 is fitted to the clutch shaft 14 so as to be rotatable and movable in the axial direction. The outer surface of the inner wheel 18 is fitted to the one-way clutch 20.
The outer wheel 19 is meshed at an outer peripheral toothed wheel portion thereof with a toothed wheel portion 17a formed in the shaft end of the electric motor 17 and fitted at the inner diametrical surface thereof with the one-way clutch 20 so that it is mutually rotatable with respect to the inner wheel 18 while not causing a relative movement in the axial direction. The one-way clutch 20 is adapted such that it transmits a torque from the outer wheel 19 to the inner wheel 18 only when the outer wheel 19 is rotated counterclockwise with respect to the inner wheel 18 as seen from the side of the pinion 15. The tooth width of the toothed wheel portion 17a formed in the end of the shaft of the electric motor 17 is formed so as to always mesh with the clutch driving element 16 even when it is displaced by the projection 9a.
A clutch spring 21 is disposed between the frame wall 1a and the clutch driving element 16 so as to press continually the clutch driving element 16 towards the pinion 15.

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The operation of the mechanism will be described. The operation for storing mechanical energy in the closing spring 89 after the closing of the movable contact 100 is as follows.
The electric motor 17 is rotated clockwise and the clutch driving element 16 is rotated counterclockwise by the toothed wheel portion 17a formed at the shaft end of the motor. When the closing spring 89 has released the mechanical energy, the projection 9a formed on a side face of the gear wheel 9 is at a position spaced apart from the clutch driving element 16. Accordingly, the clutch driving element 16 is pressed by the clutch spring 21 so that the pinion 15 and the radial grooves 18a formed in the end portion of the inner wheel 18 mesh with each other whereby the pinion 15 can be driven by the electric motor 17 through the clutch driving element 16.
When the gear wheel 9 is rotated and has slightly passed clockwise the change point of the mechanism, the projection 9a presses the clutch driving element 16 to move it toward the frame wall 1b. As a result, the linkage between the pinion 15 and the clutch driving element is disconnected. At this moment, the electric motor 17 does not drive the pinion 15.
After the disengagement of linkage between the pinion 15 and the clutch driving element 16, the gear wheel 9 is further rotated clockwise by a small amount by the force of the closing spring 89, and is stopped at its closing awaiting position by the closing latch 11.

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Since the linkage between the clutch driving element 16 and the pinion 15 is disconnected just before the point where the mechanism reaches the closing waiting position, a force due to the output torque of the electric motor 17 is not applied to the closing latch 11 even if the electric motor 17 rotates due to inertia after the stopping of the gear wheel 9.
Figure 12 is a cross-sectional view showing a relation among the projection 9a, the outer wheel 19 and the gear wheel 9 shown in Figure 10 for the purpose of explaining the problem in the above-mentioned conventional technique.
The projection 9a provided on a side face of the gear wheel 9 moves in the direction of arrow mark in Figure 12a. Symbols X1 and X2 in Figure 12b show respectively the position of the projection 9a when the projection 9a begins to contact with the outer wheel 19 (namely, the clutch begins to disconnect) and the position of the projection 9a when the outer wheel 19 has been pushed by the projection 9a so that it has finished the movement (toward the upper portion of the paper surface of the Figure).
Since the projection 9a is brought into contact with a gentle slope formed in the outer wheel 19, there is a fair fluctuation, between the position X1 and the position X2, depending on the position of a top portion of the projection 9a (a vertical position or a height) which is brought to contact with the outer wheel 19.
As understood from Figure 10, the position of the top portion of the projection 9a varies not only depending on the height of the projection 9a but also the position of the gear wheel 9 in the axial direction, namely, a shift of the cam shaft 8 in

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the axial direction. Further, the position of the outer wheel 19 is influenced by the position of the pinion 15 in the axial direction (i.e., a position of the clutch shaft 14 movable in its axial direction). Accordingly, it is necessary that the above-mentioned fluctuation is absorbed by adjusting the height of the projection 9a so as to obtain correct operational positions X1, X2 of the clutch. In the conventional, technique there is a problem that the adjustment is difficult since a slight difference of height of the projection 9a causes a substantial change in the angular position of the gear wheel 9, and the adjustment requires a lot of labor. Specifically, in the conventional energy storing mechanism adapted to disconnect the clutch by pressing the outer wheel by means of the projection, a fluctuation is produced in angular position of the gear wheel at the time of disconnection (or connection) of the clutch due to fluctuation in the relative distance between the gear wheel and the outer wheel and , due to fluctuation in the height of the projection. This results in reduction in the performance of a circuit breaker installing the energy storing device therein. Accordingly, it is insufficient to merely adjust correctly the height of the projection to a regulated dimension, and it is necessary to finely adjust the height at an actual working site.
The 'energy storing mechanism' of the present invention is hereinafter referred to as "force storing mechanism".
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS EMBODIMENT 1

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Figure 1 is a front view showing an operation means including the force storing mechanism for a circuit breaker according to Embodiment 1 of the present invention; Figure 2 is a cross-sectional view of an important portion of the force storing mechanism taken along a line A-A in Figure 1; and Figure 3 is a diagram showing the detail of a clutch or portions related thereto in Figure 2. In Figures 1 to 3, the same reference numerals designate the same or corresponding parts as for the conventional technique, and description of these parts is omitted.
A clutch shaft 14 and the rotating shaft of an electric motor 17 are provided in parallel to a cam shaft
8, and these three shafts are drivingly connected with
each other through a gear train comprising a gear wheel
9, a pinion 15 formed in an end of the clutch shaft 14, a
clutch driving element 16 having a toothed wheel element
(an outer wheel 19) at its outer periphery, and a toothed
wheel 17a formed at an end portion of the shaft of the
electric motor 17. A clutch is constituted by the pinion
15 and the clutch driving element 16.
A force storing mechanism is composed of an assembly of elements from the electric motor 17 to a closing spring 89 via the clutch driving element 16, the pinion 15, the gear wheel 9, a link 10, a closing lever 7 and so on.
The cam shaft 8 penetrates through frame walls la, 1b

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and is supported at its penetrating portions by means of a pair of bearings. A cam 13 is fitted to the cam shaft 8 at an intermediate position between the frame walls la, 1b. The gear wheel 9 is also fitted to an end portion of the cam shaft 8 wherein the gear wheel 9 is provided with a projection (i.e., an end-face cam) 9a on the surface at the side of the frame wall la and a guiding circular plate 9b so that the cam shaft 8, the cam 13 and the guiding circular plate 9b are rotated as a one-piece body by the rotation of the gear wheel 9. The cam shaft 8 is prevented from moving in its axial direction beyond a play formed in the bearings.
The clutch shaft 14 provided with the pinion 15 at its one end at the side of the frame wall la penetrates through the frame walls la, 1b and is supported at its penetrating portions by means of a pair of bearings so as to be rotatable and movable in its axial direction to some extent.
The pinion 15 comprises a toothed wheel portion 15a meshed with the gear wheel 9, an annular groove 15d into which the guiding circular plate 9b is fitted, and a small toothed wheel portion 15c meshed with radial grooves 18b formed in an inner wheel 18. The clutch driving element 16 is fitted to the clutch shaft 14 so as to be movable in the axial direction. The travelling distance of the clutch driving element 16 is regulated by the height of the projection 9a provided on the gear

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wheel 9. When the clutch driving element 16 is pressed by the projection 9a to be moved toward the frame wall lb, the meshing engagement between the small toothed wheel portion 15c and the radial grooves 18a of the inner, wheel 18 is disconnected- The projection 9a provided on the gear wheel 9 is adapted such that when the gear wheel 9 is rotated clockwise from a position where the gear wheel 9 has slightly passed clockwise the change point of the mechanism to a suitable position for a closing awaiting position, the projection 9a presses the clutch driving element 16 toward the frame wall lb to cause a displacement of the element 16 on the clutch shaft 14 by a predetermined distance, whereby the meshing engagement between the small toothed wheel portion 15c and the radial grooves 18a of the inner wheel 18 is disconnected so that a rotating force of the electric motor 17 is not transmitted to the pinion 15.
The clutch driving element 16 is constituted by the inner wheel 18, the outer wheel 19 and an one-way clutch 20. The inner wheel 18 is fitted to the clutch shaft 14 so as to be rotatable and movable in the axial direction. The outer diametrical surface of the inner wheel 18 is fitted to the one-way clutch 20. Further, the end portion facing the small toothed wheel portion 15c, of the inner wheel 18 is provided with the radial grooves 18a having the same number of teeth as the small toothed wheel portion 15c so that they are meshed with each

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other.
The outer wheel 19 is meshed at an outer peripheral toothed wheel portion thereof with a toothed wheel portion 17a formed in the shaft end of the electric motor 17 and fitted at the inner diametrical surface thereof with the one-way clutch 20 so that it is mutually rotatable with respect to the inner wheel 18 while not causing a relative movement in the axial direction. The one-way clutch 20 is so adapted that it transmits a rotational torque from the outer wheel 19 to the inner wheel 18 only when the outer wheel 19 is rotated counterclockwise with respect to the inner wheel 18 as seen from the side of the pinion 15. The tooth width of the toothed wheel portion 17a formed in the shaft end of the electric motor 17 is so adapted that, even when the clutch driving element 16 is displaced by the projection 9a, they are continually meshed with each other.
A clutch spring 21 for continually pressing the clutch driving element 16 toward the pinion 15 is provided between the frame wall la and the clutch driving element 16.
The annular groove 15d is formed in the pinion 15 at a position facing a side surface of the gear wheel 9, and the guiding circular plate 9b is firmly attached to the side surface of the gear wheel 9. The outer diameter of the guiding circular plate 9b is substantially equal to or slightly larger than the outer diameter of the gear

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wheel 9. The relationship between the thickness of the guiding circular plate 9b and the width of the annular groove 15d is such that the guiding circular plate 9b is fitted to the annular groove 15b without an excessive clearance while it is freely movable.
The operation of the force storing mechanism will be described. A series of the closing operations, i.e., the disconnection of a closing latch 11 by means of a closing trigger mechanism 12, the movement of the mechanism comprising the closing lever 1, the gear wheel 9 and the cam 11 by discharging a mechanical energy stored in the closing spring, and the closing of the movable contact 100 are the same as that in the conventional operation mechanism.
The operation for storing a mechanical energy in a closing spring 89 after the closing of the movable contact 100 is as follows.
The electric motor 17 is rotated clockwise and the clutch driving element 16 is rotated counterclockwise by the tooth wheel portion 17a formed in the shaft end of the electric motor 17. In a state that the closing spring has discharged the mechanical energy, the projection 9a provided on a side surface of the gear wheel 9 is at a position apart from the clutch driving element 16. Accordingly, the clutch driving element 16 is pressed by the clutch spring 21, and the small toothed wheel portion 15c is brought to mesh with the radial

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grooves 18a formed in an end portion of the inner wheel 18, whereby the pinion 15 is rotated in the same direction as the clutch driving element 16. When the gear wheel 9 being rotated has slightly passed clockwise the change point of the mechanism, the projection 9a presses the clutch driving element 16 to move it toward the frame wall lb. Thus, the linkage between the pinion 15 and the clutch driving element 16 is disconnected. After the disengagement of linkage between the pinion 15 and the clutch driving element 15, the gear wheel 9 is furthermore rotated clockwise by a small amount and is stopped at its closing awaiting position by the closing latch 11.
The relative positional relation in axial direction between the clutch shaft 14 and the cam shaft 8 is regulated by means of the annular groove 15d formed in the pinion 15 and the guiding circular plate 9b provided at a side surface of the gear wheel 9, The linkage between the small toothed wheel portion 15c and the clutch driving element 16 is disconnected at a position which is determined by the; shape (the height) of the projection 9a and the thickness of the small toothed wheel portion 15c.
Since the linkage between the clutch driving element 16 and the small toothed wheel portion 15c is disconnected from the point immediately before the reaching of the mechanism to its closing awaiting

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position, a force due to an output torque of the electric motor 17 does not act upon the closing latch 11 and the gear wheel 9 even if the electric motor 17 rotates after the stopping of the gear wheel 9.
In the above-mentioned, the annular groove 15d is provided between the toothed wheel portion 15a which meshes with the gear wheel 19 and the toothed wheel portion 15c which meshes with the radial grooves 18a of the inner wheel. However, as shown in Figure 4, an annular groove 15d may be formed in the pinion 15 at a position near the free end of the pinion, and a guiding circular plate 9b is fixed to the gear wheel 9 at its another side surface so that the guiding circular plate 9b is fitted to the annular groove 15d. EMBODIMENT 2
Figure 5 shows another embodiment of the present invention which minimizes the wearing the annular groove 15d due to continuous friction of the groove 15d to the guiding circular plate 9b. Further, the embodiment 2 eliminates a problem in assembling operations of the guiding circular plate 9b in Embodiment 1 wherein the guiding circular plate 9b having a relatively large dimensions is provided at a side surface of the gear wheel 9.
A correct positional relation between the gear wheel 9 and the pinion 15 can be maintained only during a state that the projection 9a is in contact with the outer wheel

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19 in the rotation of the gear wheel 9 (namely, it is merely in an angle of about 10° (degree)), and it is unnecessary for the positional relation to be precise in an angular region other than the projection 9a is in contact with the outer wheel 19.
For this purpose, the guiding plate to be provided at a side surface of the gear wheel 9 is formed to have a circular arc shape (designates as 9d in Figure 5) which should be provided in a necessary angular range in the gear wheel 9. Figure 5a is a plane view showing the gear wheel 9 and the circular arc plate 9d, and Figure 5b is a side view of them.
The circular arc plate 9d is in a sectorial shape or a circular arc shape. Both end portions where the circular arc plate 9d fit into the annular groove 15d are tapered as designated as reference numeral 9e. Thus, even when the gear wheel 9 is rotated at a high speed, the circular arc plate 9d can smoothly be inserted in the groove 15d. In this case,, the width of the groove 15d and the thickness of the circular arc plate 9d should be slightly larger than the dimension of a play of the clutch shaft 14 whereby there is no danger of the impinging of the circular arc plate 9d against the pinion 15. EMBODIMENT 3
Figure 6 shows another embodiment of the present invention.

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In Figure 6, an annular groove 9c is formed at a position near the end portion opposite the side where the projection 9a is formed, of the gear wheel 9. A guiding circular plate 15e is provided on the pinion 15 at the position corresponding to the annular groove 9c. With this provision, the linkage between the pinion 15 and the clutch driving element 16 can correctly be disconnected. EMBODIMENT 4
Figure 7 shows another embodiment of the present invention.
As shown in Figure 7, a guiding circular plate 15e and a guiding circular plate 15f are provided on the pinion 15 so that the guiding circular plates 15e, 15f are in slide-contact with both side surfaces of the gear wheel 9. With this, the linkage between the pinion 15 and the clutch driving element 16 can correctly be disconnected. In this embodiment, cutting operations for the groove in Embodiment 1, 2 and 3 are unnecessary.
In the force storing mechanism for a circuit breaker according to Embodiment 1 and Embodiment 3, the annular groove and the guiding circular plate to be fitted to the groove are provided so that the relative position in axial direction between the pinion and the gear wheel is always kept constant. Accordingly, by correctly adjusting the height of the end-face cam (the projection) provided at a side surface of the gear wheel to a previously determined height, an angular position of the

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gear wheel at which the clutch operates can correctly be determined. Further, re-adjustment of the height of the projection is unnecessary.
In the force storing mechanism for a circuit breaker according to Embodiment 2 of the present invention, the circular arc plate which extends to only a required angular range in the circumference of the gear wheel is used. Accordingly, an amount of wearing of the annular groove formed in the pinion is small.
In the force storing mechanism for a circuit breaker according to Embodiment 4 of the present invention, a relative positional relation in axial direction between the pinion and the gear wheel is kept constant by interposing the gear wheel between two guiding circular plates. Accordingly,an angular range of the gear wheel at which the clutch operates is correctly determined by correctly adjusting the height of the end-face cam (projection) provided at a side surface of the gear wheel to a regulated value. Further, re-adjustment through gauging works is unnecessary.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

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WE CLAIM :
1. An energy storing mechanism having a spring system for a circuit breaker,
wherein energy stored in a breaking spring is discharged to effect a circuit opening
operation to a contact, and energy is stored in the breaking spring, by means of a cam
shaft and a cam fixed to the cam shaft via a driving means which is driven by a motor,
said energy storing mechanism being characterized by :
a gear wheel fixed to a cam shaft;
a pinion meshing with said gear wheel;
a clutch driving element provided on the same axis as said pinion, which constitutes a clutch together with said pinion, and is driven by an electric motor; and
an end-face cam provided at a side surface of the gear wheel and adapted to press the clutch driving element at or near a stationary position of the gear wheel to release the connection between the pinion and the clutch driving element, wherein said gear wheel has a guiding circular plate fixed to a side surface of the gear wheel, and said pinion has a groove fitted to the guiding circular plate so as to maintain a relative position in axial direction of the gear wheel and the pinion to be constant.
2. Energy storing mechanism having a spring system for a circuit breaker as
claimed in claim 1 , wherein a circular arc plate is provided instead of the guiding
circular plate, at the periphery of said gear wheel in the vicinity of the position where the
end-face cam is provided

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3. An energy storing mechanism having a spring system for a circuit breaker,
wherein energy stored in a breaking spring is discharged to effect a circuit opening
operation to a contact, and energy is stored in the breaking spring, by means of a cam
shaft and a cam fixed to the cam shaft via a driving means which is driven by a motor,
said energy storing mechanism being characterized by :
a gear wheel fixed to a cam shaft;
a pinion meshing with said gear wheel;
a clutch driving element provided on the same axis as said pinion, which constitutes a clutch together with said pinion, and is driven by an electric motor; and
an end-face cam provided at a side surface of said gear wheel and adapted to press the clutch driving element at or near a stationary position of the gear wheel to release the connection between the pinion and the clutch driving element, wherein said pinion has a guiding circular plate fixed to a side surface of the gear wheel, and the gear wheel has a groove fitted to the guiding circular plate so as to maintain a relative position in axial direction of the gear wheel and the pinion to be constant.
4. An energy storing mechanism having a spring system for a circuit breaker,
wherein energy stored in a breaking spring is discharged to effect a circuit opening
operation to a contact, and energy is stored in the breaking spring, by means of a cam
shaft and a cam fixed to the cam shaft via a driving means which is driven by a motor,
said energy storing mechanism being characterized by :
a gear wheel fixed to a cam shaft;
a pinion meshing with said gear wheel;

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a clutch driving element driving element provided on the same axis as said pinion, which constitutes a clutch together with said pinion, and is driven by an electric motor; and
an end-face cam provided at a side surface of said gear wheel and adapted to press the clutch driving element at or near a stationary position of the gear wheel to release the connection between the pinion and the clutch driving element, wherein said pinion has two guiding circular plates fixed to an intermediate position between the free end and the tooth surface of the pinion and the gear wheel is fitted to the space between the two guiding circular plates so as to maintain a relative position in axial direction of the gear wheel and the pinion to be constant.
5. An energy storing mechanism having a spring system for a circuit breaker,
substantially as herein described, particularly with reference to and as illustrated in the accompanying drawings.
An energy storing mechanism having a spring system for a circuit breaker, wherein energy stored in a breaking spring (89) is discharged to effect a circuit opening operation to a contact, and energy is stored in the breaking spring, by means of a cam shaft (8) and a cam (13) fixed to it via a driving means which is driven by a motor, is characterized by:
a gear wheel (9) fixed to the cam shaft, and a pinion (15) meshing with the gear wheel;
a clutch driving element (16) provided on the same axis as the pinion, which constitutes a clutch together with the pinion, and is driven by an electric motor (17); and
an end-face (9a) cam provided at a side surface of the gear wheel and adapted to press the clutch driving element at or near a stationary position of the gear wheel to release the connection between the pinion and the clutch driving element, wherein the gear wheel (9) has a guiding circular plate (9b) fixed to a side surface thereof, and the pinion (15) has a groove (15d) fitted to the guiding circular plate so as to maintain a relative position in axial direction of the gear wheel and the pinion to be constant.

Documents:

00204-cal-1998 abstract.pdf

00204-cal-1998 claims.pdf

00204-cal-1998 correspondence.pdf

00204-cal-1998 description(complete).pdf

00204-cal-1998 drawings.pdf

00204-cal-1998 form-1.pdf

00204-cal-1998 form-2.pdf

00204-cal-1998 form-3.pdf

00204-cal-1998 form-5.pdf

00204-cal-1998 g.p.a.pdf

00204-cal-1998 letters patent.pdf

00204-cal-1998 priority document others.pdf

00204-cal-1998 priority document.pdf

00204-cal-1998 reply f.e.r.pdf

204-CAL-1998-FORM-27.pdf


Patent Number 207087
Indian Patent Application Number 204/CAL/1998
PG Journal Number 21/2007
Publication Date 25-May-2007
Grant Date 23-May-2007
Date of Filing 09-Feb-1998
Name of Patentee MITSUBISHI DENKI KABUSHIKI KAISHA
Applicant Address 2-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100
Inventors:
# Inventor's Name Inventor's Address
1 ICHIZO NAKATANI C/O MITSUBISHI DENKI KABUSHIKI KAISHA 2-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100
2 MITSUHARU OKUNO C/O MITSUBISHI DENKI KABUSHIKI KAISHA 2-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100
3 MASAO NARITA C/O MITSUBISHI DENKI KABUSHIKI KAISHA 2-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100
PCT International Classification Number F16H 55/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 9-100292 1997-04-17 Japan