Claims:1. A motor driven spring charging device 3, comprising:
at least one universal motor 4;
at least one gear box arrangement consisting of at least one worm screw 5 operatively coupled with at least one worm wheel 7;
at least one epicyclic gear 8 pivoted on either sides of at least one plate 9;
wherein the worm wheel 7 and the epicyclic gear 8 are operatively connected by and rotates about at least one center pin 6 and adapted to perform at least a switching operation and simultaneously generating a torque required to charge at least one mechanism springs of a contact system of at least one circuit breaker.

2. The motor driven spring charging device as claimed in claim 1, is adapted to utilize a rotation of a driving motor to increase the spring charging speed, and thereby reduces the time required for spring charging operation and reducing idling or wasted energy.

3. The motor driven spring charging device as claimed in claim 1, wherein the universal motor 4 rotates the worm screw 5, the worm screw 5 is coupled to at least one shaft.

4. The motor driven spring charging device as claimed in claim 1, wherein the worm screw 5 is meshed with teeth of the worm wheel 7.

5. The motor driven spring charging device as claimed in claim 1, wherein the worm screw 5 drives the worm wheel 7 in at least a clockwise direction by using the universal motor 4.

6. The motor driven spring charging device as claimed in claim 1, wherein the worm wheel 7 is adapted to be operatively coupled to at least one a sun gear 10 mounted on plate 9, such that the rotation of the worm wheel 7 rotates the sun gear 10 in a same direction of the rotation of the worm wheel 7.

7. The motor driven spring charging device as claimed in claim 6, wherein the sun gear 10 is surrounded by at least three planet gears 14, 15, 16, mounted on the plate 9 and arranged in such a manner that when the sun gear 10 rotates in clockwise direction, all the planet gears 14, 15, 16 rotate in anti-clockwise direction.

8. The motor driven spring charging device as claimed in claim 1 further comprises a plurality of pins, riveted pins 18, 19, adapted to charge the springs at a higher speed i.e. at less time.

9. A circuit breaker comprising:
a contact system;
an operating mechanism, and
a motor driven spring charging device 3 as claimed in claim 1.

10. The circuit breaker as claimed in claim 9, wherein the motor driven spring charging device 3 further comprises: a universal motor, a worm wheel, and an epicyclic gear.

11. The circuit breaker as claimed in claim 9, wherein the motor driven spring charging device 3 is adapted to charge the main springs of operating mechanism.

12. The circuit breaker as claimed in claim 10, wherein the worm wheel and the epicyclic gear are arranged in pre-defined space to result in the increase in torque.

13. The circuit breaker as claimed in claim 10, wherein the epicyclic gear further comprises at least a ring gear as an integral part, the center of rotation of the ring gear and the operating mechanism, specifically a ratchet cover of the operating mechanism, are not concentric so the torque of the ring gear is increased while being transferred to the ratchet.

14. The circuit breaker as claimed in claim 13, wherein a maximum distance between the center of rotation of the ring gear and that of the ratchet cover is desirable according to the torque required.

15. The circuit breaker as claimed in claim 13, wherein the ring gear consists of one or more pins riveted on an outer wall, the pins are spaced at an equal distance from the center of the ring gear such that an imaginary line joining the two pins passes through the center of the ring gear.

16. The circuit breaker as claimed in claims 13 and 15, wherein the distance from the center of rotation of the ring gear at which the two pins are riveted is adapted to contribute to the torque being transferred to the ratchet of the operating mechanism according to the torque required.

17. The circuit breaker as claimed in claims 14 and 16, wherein the distances are selected in a way that the output torque being applied on the ratchet is preferably 150 times that of the torque of the universal motor of the motor driven spring charging device 3.
18. The circuit breaker as claimed in claim 16, wherein the riveted pins utilized to charge the springs results in reduction of spring charging time as a full rotation of the ring gear is utilized to the maximum extent resulting in utilizing the motors output efficiently.
, Description:TECHNICAL FIELD

[001] The present subject matter described herein, in general, relates to circuit breaker, and more particularly relates to a motor driven spring charging device to store energy to enable closing operation of mechanism of circuit breaker in remote location. Post closure the breaker can carry and break current under normal circuit condition and also break during abnormal conditions.

BACKGROUND

[002] A circuit breaker is an electrical protection device which can make, break and carry current in normal condition. When there is a fault in the system due to overload, short circuit etc. circuit breaker can break and clear the fault.

[003] Circuit breaker switch is toggled between Close and Open position by means of an Operating Mechanism. In high rating circuit breakers high contact pressure is applied between fixed contact and moving contact of the circuit breaker. The applied contact pressure acts against the mechanism springs. So, mechanism springs are designed to deliver high force which is required to withstand the applied contact pressure. The main mechanism springs are linked to the contact system of the circuit breaker to enable make and break operations of the circuit breaker. For making operation, the said mechanism springs are charged by compressing to a predefined length. Once the springs are fully charged, the high energy stored in the mechanism springs are delivered through the mechanism linkages to the contact system to make the circuit breaker ON. When there is a fault in the system, release detects the fault and issues a TRIP command to the mechanism, resulting in opening of the breaker. Once the fault is cleared, the circuit breaker should be switched ON to carry out normal rated current.

[004] Whenever the circuit breaker is in OFF condition, either due to occurrence of fault in the system or in healthy condition, to make the breaker ON the mechanism springs are to be charged fully. Very high torque is required to charge the mechanism springs. Moreover springs cannot be fully charged in one stroke; several strokes are required. This charging operation can be done manually or electrically.

[005] As very high torque and several strokes are required to charge the springs, it proves to be a very tedious job if the spring charging operation is carried out manually. As a result, it is desirable to have a provision for charging the springs electrically. Springs can be charged electrically using a motor driven spring charging device. If the circuit breaker is installed in remote location, mechanism springs cannot be charged manually. In such a scenario, mechanism springs must be charged electrically using a motor driven spring charging device.

[006] Motor driven spring charging device typically consists of at least one motor which drives a mechanical linkage system to deliver higher torque required to charge the mechanism springs.

[007] Motor driven spring charging device is coupled to the operating mechanism of the circuit breaker to charge the mechanism spring fully to enable closing operation of the breaker. The motor driven spring charging device is required to deliver high torque which is required to charge the springs fully. Moreover spring charging operation should be carried out in less time. Generally motor charges the springs only during half of its shaft rotation; consequently remaining half of its rotation involves idling or wasted energy. Motor driven spring charging device has to be robust to enable multiple switching operations.

[008] The above-described deficiencies of today's motor driven spring charging device are merely intended to provide an overview of some of the problems of conventional systems, and are not intended to be exhaustive. Other problems with conventional systems and corresponding benefits of the various non-limiting embodiments described herein may become further apparent upon review of the following description.

SUMMARY OF THE INVENTION

[009] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

[0010] An object of the present invention is to provide a robust spring charging device driven by a motor to enable multiple switching operations, at the same time ensuring desired output torque required to charge the mechanism springs. The present invention also ensures 70 percent utilization of a rotation of the driving motor to increase the spring charging speed, thus reducing the time required for spring charging operation; also reducing idling or wasted energy.

[0011] Accordingly, the present invention provides a motor driven spring charging device which drives the ratchet wheel in the charging direction during three quarter of the turn of the motor driven spring charging device.

[0012] The present invention discloses a motor driven spring charging device which drives the ratchet wheel in the charging direction during three quarter of the turn of the motor driven spring charging device. The present invention deals with construction of the motor driven spring charging device consisting of worm-wheel and epicyclic gear to deliver high torque required to charge the main springs. The said spring charging device also consists of multiple pins that help in charging the springs at a higher speed i.e. at less time.

[0013] Also, in the present invention, in order to amplify the low torque which is delivered by the universal motor, the worm wheel and the epicyclic gear are used. The worm screw being coupled to the output shaft of the universal motor drives the worm wheel. The combination of worm screw and worm wheel amplifies the output torque of the universal motor by 25 times. The worm wheel again drives an epicyclic gear to further amplify the torque of the universal motor. The epicyclic gear of the present invention consists of sun gear as the input gear and ring gear as the output gear. The sun gear and the ring gear are coupled by at least one planet gear. This arrangement of the epicyclic gear amplifies the output torque of the worm wheel preferably by three times.

[0014] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0015] Figure 1 illustrates an isometric view of the 4 pole Circuit Breaker cassette with mechanism and motor driven spring charging device mounted on it, in accordance with an embodiment of the present subject matter.

[0016] Figure 2 illustrates an isometric view of the motor driven spring charging device, in accordance with an embodiment of the present subject matter.

[0017] Figure 3 illustrates an isometric view of the motor driven spring charging device without ring gear, in accordance with an embodiment of the present subject matter.

[0018] Figure 4 illustrates an isometric view of the motor driven spring charging device with ring gear, in accordance with an embodiment of the present subject matter.

[0019] Figure 5 illustrates an isometric view of the motor driven spring charging device coupled with mechanism, in accordance with an embodiment of the present subject matter.

[0020] Figure 6 illustrates an exploded view of the motor driven spring charging device coupled with mechanism. The main springs shown here are in discharged condition, in accordance with an embodiment of the present subject matter.

[0021] Figure 7 illustrates a detailed view of the first pin driving the ratchet and pawl assembly in forward direction, in accordance with an embodiment of the present subject matter.

[0022] Figure 8 illustrates a detailed view of the first pin getting disengaged from the ratchet and pawl assembly, in accordance with an embodiment of the present subject matter.

[0023] Figure 9 illustrates a detailed view of the second pin and the ratchet and pawl assembly moving towards each other, in accordance with an embodiment of the present subject matter.

[0024] Figure 10 illustrates a detailed view of the second pin driving the ratchet and pawl assembly in forward direction, in accordance with an embodiment of the present subject matter.

[0025] Figure 11 illustrates a detailed view of the second pin getting disengaged from the ratchet and pawl assembly, in accordance with an embodiment of the present subject matter.

[0026] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0027] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0028] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0029] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0030] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0031] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0032] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

[0033] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0034] In one implementation, the present invention deals with construction of a motor driven spring charging device which is capable of delivering high torque required to charge the springs. It also deals with a feature in the spring charging device that helps in charging the springs at a higher speed i.e. at less time.

[0035] Referring now to figure 1, an isometric view of the 4 pole circuit breaker 1 with mechanism 2 and motor driven spring charging device 3 mounted on it is illustrated.

[0036] Referring now to figure 2, an isometric view of the motor driven spring charging device 3 is illustrated in accordance with an embodiment of the present invention. As shown in the figure 2, the motor driven spring charging device consists of a universal motor 4 and a gear box arrangement consisting of a worm screw 5 and a worm wheel 7 and epicyclic gear 8 pivoted on either sides of a plate 9. The worm wheel 7 and epicyclic gear 8 rotates about the center pin 6.

[0037] In the motor driven spring charging device a low torque universal motor 4 rotates a worm screw 5 which is coupled to its shaft. The worm screw 5 is meshed with teeth of a worm wheel 7. Being rotated by the motor 4, the worm screw 5 drives the worm wheel 7 in clockwise direction.

[0038] As shown in figure 3, a sun gear 10 is attached to the worm wheel 7 in such a way that when the worm wheel 7 rotates, the sun gear 10 also rotates in the same direction. As the worm wheel 7 is rotating in clockwise direction, the sun gear 10 also rotates in clockwise direction. Three planet gears 14, 15, 16 are pivoted in a fixed plate 9 around the sun gear 10. The three planet gears 14, 15, 16 are equidistant from each other. As depicted in figure 4, a ring gear 17 wraps around the three planet gears 14, 15, and 16. The center of rotation of the ring gear 17 is same as that of the sun gear 10. The ring gear 17 has internal teeth. The central sun gear 10 meshes with accurately positioned planet gears 14, 15 and 16 around it which in turn mesh with the internal teeth of the outer ring gear 17. In this case sun gear 10 is the input gear and ring gear 17 is the output gear.

[0039] When the sun gear 10 is rotated in clockwise direction, all the planet gears 14, 15, 16 rotate in anti-clockwise direction which in turn rotates the ring gear 17 in anti-clockwise direction. Use of worm wheel 7 and epicyclic gear 8, arranged in minimum space, ultimately results in increase in torque in only two stages with use of minimum number of components. Considering friction and efficiency of the system, the output torque of the ring gear is approximately 70 times that of the torque of the universal motor.

[0040] As shown in figure 4, two pins 18, 19 are riveted at the outer side of the ring gear 17. The said two pins are at equal distance from the center of the ring gear. Imaginary line joining the two pins passes through the center of the ring gear.

[0041] Figure 5 shows an isometric view of the motor driven spring charging device 3 coupled with mechanism 2. An exploded view of figure 5 is shown in figure 6. Figure 6 depicts how the motor driven spring charging device 3 is coupled with the mechanism 2. The main springs 25, 26 shown here are in discharged condition. There is a shaft pin 22 which is an integral part of the mechanism 2. A ratchet 20 is coupled to the mechanism 2 and it rotates about the pivot pin 22.

[0042] As shown in figure 6, the motor driven spring charging device 3 is coupled with the mechanism 2 in such a way that the center of rotation 6 of the ring gear 17 and the center of rotation 22 of the ratchet cover 21 is not concentric. Such an arrangement is made so that output torque of the ring gear 17 further gets increased while getting transferred to the ratchet 20 via ratchet cover 21. Maximum distance between center of rotation of the ring gear 17 and that of the ratchet cover 21 is desirable. Higher the distance higher is the torque achieved. The distance from the center of rotation of the ring gear 17 at which the two pins 18, 19 are riveted also contributes to the torque getting transferred to the ratchet 20 via ratchet cover 21. Lesser said distance higher is the torque achieved. The above mentioned distances are selected in a way that the achieved output torque which is applied on the ratchet 20 is approximately 150 times that of the torque of the universal motor 4.

[0043] As shown in figure 7, when the motor 4 drives the spring charging device 3 one of the riveted pins 18,19 come in contact with the cam surface 27 of ratchet cover 21 which is an integral part of the mechanism 2. Here in figure 7, it is shown that the riveted pin 18 is in contact with the cam surface 27 of ratchet cover 21, thus rotating the ratchet cover 21 in anti-clockwise direction. After a certain angle of rotation the riveted pin 18 gets disengaged from the ratchet cover 21. The position is shown in figure 8.

[0044] As soon as the first pin 18 gets disengaged, the ratchet cover 21 moves in clockwise direction towards the second pin 19 as shown in figure 1 and comes in contact with the second riveted pin 19. Then the second riveted pin 19 again rotates the ratchet cover 21 in anti-clockwise direction. After a certain angle of rotation, the second riveted pin 19 also gets disengaged and ratchet cover 21 moves in clockwise direction to get engaged with the first riveted pin 18 which again drives the ratchet cover 21 in anti-clockwise direction. This operation continues till the main mechanism springs are not fully charged. Use of multiple riveted pins 18, 19 to charge the springs results in reduction of spring charging time because full rotation of the ring gear 17 is utilized to the maximum extent which results in utilizing the motor output efficiently. As a result, idling or wasted energy is reduced.

[0045] The distance of the two pins 18, 19 from the center of rotation of the ring gear 17 is optimized such that high torque is achieved to charge the mechanism springs 25, 26 fully in least possible time.

[0046] Depending on the required output torque and the required spring charging time number of teeth of the gears, distance between center of rotation of ring gear 17 and that of ratchet cover 21, distance between center of rotation of ring gear 17 and that of the two pins 18,19, number of pins 18,19 can be changed.

[0047] In one implementation, a circuit breaker comprising of a contact system, operating mechanism, motor driven spring charging device is disclosed. The Motor driven spring charging device further comprise a universal motor, worm wheel, epicyclic gear. The motor driven spring charging device charges the main springs of operating mechanism. The present invention disclosed use of worm wheel and epicyclic gear, arranged in minimum space, ultimately results in increase in torque in only two stages with use of minimum number of components. Considering friction and efficiency of the system, the output torque of the ring gear is approximately 70 times that of the torque of the universal motor. The center of rotation of the ring gear, which is an integral part of the epicyclic gear and that of the ratchet cover, which is an integral part of the mechanism, is not concentric. Such an arrangement is made so that output torque of the ring gear further gets increased while getting transferred to the ratchet via ratchet cover. Maximum distance between center of rotation of the ring gear and that of the ratchet cover is desirable. Higher the distance higher is the torque achieved. The distance from the center of rotation of the ring gear at which the two pins are riveted also contributes to the torque getting transferred to the ratchet via ratchet cover which is an integral part of operating mechanism. Lesser said distance higher is the torque achieved. The distance is selected in a way that the achieved output torque which is getting applied on the ratchet is approximately 150 times that of the torque of the universal motor. Use of multiple riveted pins to charge the springs results in reduction of spring charging time because full rotation of the ring gear is utilized to the maximum extent which results in utilizing the motor output efficiently. As a result, idling or wasted energy is reduced. The distance of the two pins from the center of rotation of the ring gear is optimized such that high torque is achieved to charge the mechanism springs fully in least possible time. Depending on the required output torque and the required spring charging time number of teeth of the gears, distance between center of rotation of ring gear and that of ratchet cover, distance between center of rotation of ring gear and that of the two pins, number of pins can be changed.

[0048] It may be clearly understood by a person skilled in the art that for the purpose of convenient and brief description, for a detailed working process of the foregoing system, devices, and unit, reference may be made to a corresponding process in the foregoing device/apparatus embodiments, and details are not described herein again.

[0049] In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus, and device may be implemented in other manners. For example, a plurality of units or components or mechanisms may be combined or integrated into another system, or some features may be ignored or not performed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented through some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electronic, mechanical, or other forms.

[0050] The various mechanisms described as separate parts may or may not be physically separate, and the parts displayed as mechanisms may or may not be physical units, may be located in one position, or may be distributed at various location of the device. Some or all of the units may be selected to achieve the objective of the solution of the embodiment according to actual needs.

[0051] In addition, the mechanisms in the embodiments of the present invention may be integrated into one processing unit, or each of the mechanisms may exist alone physically, or two or more mechanisms may be integrated into one mechanism.

[0052] Although a motor driven spring charging device for a circuit breaker with reduced spring charging time is disclosed, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or methods or devices described. Rather, the specific features are disclosed as examples of implementations of motor driven spring charging device for a circuit breaker with reduced spring charging time.