DESC:TECHNICAL FIELD

[001] The present subject matter described herein, in general, relates to clutch systems integrated into a gearbox and more particularly to a mechanism that provides mechanical override capability on completion of a predetermined degree of rotational motion.

BACKGROUND

[002] An electrical protection device such as a circuit breaker is typically designed to detect abnormal conditions in a monitored circuit and make or break electrical connections in response to those conditions. The operating mechanism of the circuit breaker is realized by using a mechanism spring which provides mechanical force necessary to drive a latch and trip mechanism which opens and closes a pair of separable contacts, so as to make or break electrical connections in the circuit. Systems for electrically charging the mechanism spring generally involve either compression or extension of the spring.

[003] Currently, a charging system for charging the mechanism spring uses a clutch assembly and a ratchet system to achieve mechanical cut-off between the gears and the charging shaft once springs are charged fully. Clutch assembly consists of a ratchet, pawl, pawl link and an extension spring. Pawl is riveted, free to rotate on pawl link and is engaged with ratchet teeth by the extension spring. When charging is completed, pawl rides over a roller rising above ratchet teeth and hence mechanical cut-off is achieved through rotational movement. Once the energy of mechanism springs is used, pawl reengages with the ratchet and Electrical charging device (ECD) is ready for the next operation.

[004] The prior art document, US 3773995 A discloses a circuit breaker operating mechanism characterized by a crank shaft, a closing spring connected to the crank shaft, motor-operating structure for driving the crank shaft to charge the closing spring, a ratchet wheel mounted on the crank shaft, a reciprocating pawl structure supported to drive the ratchet wheel, a motor comprising an output shaft and cam means or driving means on the output shaft operable upon each revolution of the output shaft to operate the pawl structure to advance the ratchet wheel to thereby charge the closing spring, the cam means being operable in directions toward and away from the reciprocating pawl structure, and spring means attached to the output shaft for urging the reciprocating pawl structure only in the direction of advancement of the ratchet wheel.

[005] The prior art document, US 4146764 A discloses a circuit breaker having a spring operated closing mechanism for establishing contact between the moving contact and the stationary contact; a ratchet and pawl spring charging system in which the ratchet wheel is combined with the crank arm for the closing spring which in turn operates the moving contact arm toward closed position. The pawl carrier plates are mounted on and rotate on the outer periphery of the combined ratchet wheel and crank arm. A motor operated mechanism may also be connected through the same members.

[006] However, the existing spring charge mechanism results in excessive fly-off of the pawl and also produces stresses on the rivet which is used to assemble pawl and pawl link. This additional stress results in breakage of the rivet and ultimately results in non-functioning of mechanical cut-off system. In some cases damage to pawl and pawl link is also observed. Such failure also takes place due to shearing of the hook of the pawl link extension spring.

[007] Thus, in view of the above drawbacks, there exists a dire need for a mechanical override system so as to avoid damages to components of the charging system, be it the motor, the gearbox, the external charging member or the spring to be charged.

SUMMARY OF THE INVENTION

[008] 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.

[009] An object of the present invention is to provide a mechanical override mechanism on the completion of a predetermined degree of rotation which completes the charging operation.

[0010] Another object of the present invention is to provide a mechanical override mechanism that replaces existing rotational mechanical override system with radial translation clutch assembly.

[0011] Yet another object of the present invention is to provide a mechanical override mechanism that enables positive consistent engagement during torque transmission due to simple compression spring force.

[0012] Yet another object of the present invention is to provide a mechanical override mechanism that eliminates the requirement of highly stressed, low strength components.

[0013] Yet another object of the present invention is to provide a cost effective component design in a mechanical override system.

[0014] Still another object of the present invention is to provide a mechanical override system that provides better mechanical cutoff operation by means of a reliable cam action.

[0015] Accordingly, a radial translation clutch assembly system to achieve a mechanical cut-off between gears of at least one gearbox and at least one charging shaft once at least one spring is completely charged in switchgears is disclosed. The radial translation clutch assembly system comprises at least one gearbox base plate, at least one gearbox output shaft, at least one ratchet, at least one cam link, at least one cam, at least one cutoff springs, and at least one roller. The cam link is adapted to achieve a linear translation of said cam in radial direction of gearbox output shaft (12), which allows for positive engagement and disengagement from at least one teeth of said ratchet; and said cam is adapted to receive an input force (torque) from said compression springs and achieve a torque transmission clutch function.

[0016] In one implementation, a radial translation clutch apparatus to achieve a mechanical cut-off between gears of at least one gearbox and at least one charging shaft when at least one spring is completely charged in switchgears is disclosed. The radial translation clutch apparatus comprises at least one gearbox base plate, at least one gearbox output shaft, at least one ratchet, at least one cam link, at least one cam, at least one cutoff springs, and at least one roller. The cam link is adapted to achieve a linear translation of said cam in radial direction of gearbox output shaft (12), which allows for positive engagement and disengagement from at least one teeth of said ratchet; and said cam is adapted to receive an input force (torque) from said compression springs and achieve a torque transmission clutch function.

[0017] In one implementation, a method, to achieve a mechanical cut-off between gears of at least one gearbox and at least one charging shaft once at least one spring is completely charged fully, using a radial translation clutch assembly system/ a radial translation clutch apparatus, in switchgears is disclosed. The method comprises:
· providing, using at least one cam link of said radial translation clutch assembly system/ said radial translation clutch apparatus, a linear translation of at least one cam in radial direction of gearbox output shaft (12); and
· allowing, due to said radial translation, a positive engagement and/or disengagement of said cam from at least one teeth of at least one ratchet of said radial translation clutch assembly system/ said radial translation clutch apparatus to achieve mechanical cut-off.

[0018] In one implementation, the present invention provides a mechanical override system for mechanical cut-offs in a protection device by replacing the existing rotational mechanical override system with radial translation clutch assembly so that an external charging member does not exceed the predetermined degree of rotation.

[0019] In one implementation, the present invention provides a mechanical override system that includes a gear box with a clutch operation. The mechanical override system generates torque to drive an external charging member to drive the charging of a mechanism spring in a protection device and subsequently achieves a mechanical override function.

[0020] Conventionally, systems for electrically charging a mechanism spring in a protection device by coupling of a motor to a speed reduction gearbox so as to generate more torque were known. This torque is then utilized to drive the external charging member, which delivers force by using a cam action in order to charge the spring. In contrast, the present invention provides a mechanical override system that includes a clutch operation integrated into a gearbox, which fundamentally decouples the gearbox output torque from a shaft so as to deliver a torque to the external charging member, once the charging cycle is completed.

[0021] In one implementation, the present invention provides a mechanical override system by means of cam guided in a cam link, radially translating on the gearbox output shaft. Cam interacts, by means of compression spring forces, with a ratchet on the output shaft to transmit torque and disengages to achieve mechanical override function.

[0022] In one implementation, the present invention provides a method for achieving mechanical override function. The method comprises a clutch operation integrated into a gearbox wherein the mechanical override function is achieved by means of cam guided in a cam link, radially translating on the gearbox output shaft. The cam link makes for radial translation of the cam so as to enable positive engagement and disengagement from ratchet teeth.

[0023] In one implementation, the present invention provides a cam that includes a direct cam action for torque transmission clutch function and also takes input force from two guided compression springs which provide consistent operational capability

[0024] 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:

[0025] Figure 1 illustrates an engaged view of a gear box clutch mechanism, in accordance with the subject matter of the present invention.

[0026] Figure 2 illustrates a disengaged view of gearbox clutch mechanism disengaged, in accordance with the subject matter of the present invention.

[0027] Figure 3 illustrates a gearbox clutch box assembly, in accordance with the subject matter of the present invention.

[0028] Figure 4 illustrates a gearbox output shaft, in accordance with the subject matter of the present invention.

[0029] Figure 5 illustrates a ratchet, in accordance with the subject matter of the present invention.

[0030] Figure 6 illustrates a cam link, in accordance with the subject matter of the present invention.

[0031] Figure 7 illustrates a profile placed on a cam, in accordance with the subject matter of the present invention.

[0032] Figure 8 illustrates the convention gear box system using convention components.

[0033] Figure 9 illustrates the gearbox and the components, in accordance with the subject matter of the present invention.

[0034] 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

[0035] 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.

[0036] 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.

[0037] 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.

[0038] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] Referring now to figure 1, an engaged view of gear box clutch mechanism is illustrated. In one implementation, the mechanism override system consists of a ratchet (13) which is free to rotate about the gearbox output shaft (12) and is rigidly coupled to the gear stages before it. The cam link (14) is mounted on the gearbox output shaft (12) and it rotates the output shaft (12). The cam (15) is mounted on the cam link (14) with the use of cut off springs (161 and 162). The roller (17) is riveted to the gearbox base plate (11).The driver torque originates from the electrical motor, and is transmitted via the gearbox sequentially amplifying the torque through the stages (18).

[0043] In one implementation, at the commencement of the charging operation, the torque is transmitted by the gearbox output shaft (12) is transmitted directly to the ratchet (13). Due to the particulars of assembly and the component mounting positions at the beginning of charging, the cam (15) enables positive engagement and/or disengagement with the ratchet (13).

[0044] Referring now to figure 2, a disengaged view of gear box clutch mechanism is illustrated. In one implementation, at the termination of the charging cycle, the location of the roller (17) is such that on completion of a predetermined angle of rotation of the gearbox output shaft (12), a deliberately placed profile (20) on the cam (15) interacts with the roller (16) and subsequently enabling cam (15) to move away from the ratchet (13). The cut-off springs (161 and 162) gets compressed due to this movement between the cam link (14) and cam (15). Since the cam link assembly (14-15) is free to translate radially about the gearbox output shaft (12) axis, and further disengages from the tooth of the ratchet (13). Now, the driver ratchet (13) is decoupled from the driven cam link (14) which is the mechanical override clutch action integrated into the gearbox.

[0045] Referring now to figure 3, a view of the gearbox clutch box assembly is illustrated that is involved in the present invention to achieve a mechanical override function. In one implementation, during the commencement of the charging operation, the driver torque coming to the ratchet (13) from the gearbox output shaft (12) is sequentially transferred to the cam (15) and thus, the cam link (14) and then onto the gearbox output shaft (12), culminating in the torque being delivered to the driven member (19).

[0046] In one implementation, the mechanism/device operates as it causes the discharging of the spring and a release of an external charging member. The external charging member is rigidly coupled to the gearbox output shaft (12) and hence the cam link (14) which rotates partially. This rotates the cam (15) over the roller (17) causing cut-off springs (161 and 162) to return to their original position. The engagement of the cam (15) with the ratchet (13) further enables the mechanism spring to return to their initial position of engagement and thus the charging cycle is commenced thereafter.

[0047] Referring now to figure 4, a view of the gearbox output shaft (12) is illustrated.

[0048] Referring now to figure 5, a view of the ratchet (13) is illustrated. In one implementation, the ratchet (13) is free to rotate about the gearbox output shaft (12).

[0049] Referring now to figure 6, a view of the cam link (14) is illustrated. In one implementation, the cam link (14) is mounted on the gearbox output shaft (12).

[0050] Referring now to figure 7, a view of the profile (20) on the cam (15) is illustrated. In one implementation in the event of termination of the charging cycle, the profile (20) on the cam (15) interacts with the roller (16).

[0051] Accordingly, a radial translation clutch assembly system to achieve a mechanical cut-off between gears of at least one gearbox and at least one charging shaft once at least one spring is completely charged in switchgears is disclosed. The radial translation clutch assembly system comprises at least one gearbox base plate, at least one gearbox output shaft, at least one ratchet, at least one cam link, at least one cam, at least one cutoff springs, and at least one roller. The cam link is adapted to achieve a radial translation of said cam, which allows for positive engagement and disengagement from at least one teeth of said ratchet; and said cam is adapted to receive an input force (torque) from said compression springs and achieve a torque transmission clutch function.

[0052] In one implementation, a radial translation clutch apparatus to achieve a mechanical cut-off between gears of at least one gearbox and at least one charging shaft when at least one spring is completely charged in switchgears is disclosed. The radial translation clutch apparatus comprises at least one gearbox base plate, at least one gearbox output shaft, at least one ratchet, at least one cam link, at least one cam, at least one cutoff springs, and at least one roller. The cam link is adapted to achieve a radial translation of said cam, which allows for positive engagement and disengagement from at least one teeth of said ratchet; and said cam is adapted to receive an input force (torque) from said compression springs and achieve a torque transmission clutch function.

[0053] In one implementation, a method, to achieve a mechanical cut-off between gears of at least one gearbox and at least one charging shaft once at least one spring is completely charged fully, using a radial translation clutch assembly system/ a radial translation clutch apparatus, in switchgears is disclosed. The method comprises:
· providing, using at least one cam link of said radial translation clutch assembly system/ said radial translation clutch apparatus, a radial translation of at least one cam; and
· allowing, due to said radial translation, a positive engagement and/or disengagement of said cam from at least one teeth of at least one ratchet of said radial translation clutch assembly system/ said radial translation clutch apparatus to achieve mechanical cut-off.

[0054] In one implementation, said cam interacts with said ratchet using said input force (torque) from said compression spring on said gearbox output shaft to transmit said torque and disengage to achieve said mechanical override on completion of predetermined angle of rotation.

[0055] In one implementation, said cam is guided in said cam link to radially translate said torque to said gearbox output shaft.

[0056] In one implementation, said clutch operation integrated into said gearbox and adapted to decouple said torque from said gearbox output shaft to delivers said torque to at least one external charging member, on completion of at least one charging cycle.

[0057] In one implementation, said cam interacts, using compression spring forces, with said ratchet on said gearbox output shaft to transmit said torque and disengages to achieve mechanical override.

[0058] In one implementation, said mechanical override is provided so that said external member limits within said predetermined degree of rotation and completes said charging operation.

[0059] The conventional systems as shown in figure 8, use rotation of a pawl about a pivot center on the pawl link, to engage / disengage it from the ratchet teeth. Contact is maintained between Pawl and ratchet due to extension spring force.

[0060] In contrast with the conventional systems as shown in figure 8, the present invention provides a cam which linearly translates in a radial direction of the gearbox output shaft, being guided by the cam link, allowing it to engage / disengage from the ratchet teeth as shown in figure 9. The positive contact is maintained between cam and ratchet teeth by compression spring force. Further, a cam which moves inward and outward in the radial direction of the gearbox output shaft. It is guided by the cam link which is rigidly mounted on the gearbox output shaft. The compression springs normally maintain a force on the cam pushing it radially inward toward the center of the output shaft, thus mainlining positive contact with the ratchet teeth. Mechanical cut off (i.e. Clutch) function is achieved when deliberate profile of cam interacts with roller on gearbox casing. This pushes against the compression spring force lifting cam linearly away from gearbox output shaft in a radial direction, hence causing disengagement of cam from ratchet teeth.

[0061] Some of the important features of the present invention, considered to be noteworthy are mentioned below:
1. The present invention provides a mechanical override system that replaces the drawbacks of the existing rotational mechanical override system by providing radial translation clutch assembly so as to eliminate highly stressed, low strength components.
2. The present invention provides an effective torque transmission due to consistent compression spring force.
3. The component design of the present invention is simple and cost effective.
4. The present invention provides engagement/disengagement of clutch due to positive cam action, thereby enhancing reliability of the mechanical override system.
,CLAIMS:1. A radial translation clutch assembly system to achieve a mechanical cut-off between gears of at least one gearbox and at least one charging shaft once at least one spring is completely charged in switchgears, said radial translation clutch assembly system comprising:
at least one gearbox base plate (11), at least one gearbox output shaft (12), at least one ratchet (13), at least one cam link (14), at least one cam (15), at least one cutoff springs (161, 162), and at least one roller (17), WHEREIN
said cam link is adapted to achieve a linear translation of said cam in radial direction of gearbox output shaft (12), to allow positive engagement and/or disengagement from at least one teeth of said ratchet; and
said cam is adapted to receive an input force (torque) from said compression springs and achieve a torque transmission clutch function.
2. The radial translation clutch assembly system as claimed in claim 1, wherein said cam interacts with said ratchet using said input force (torque) from said compression spring on said gearbox output shaft to transmit said torque and disengage to achieve said mechanical override on completion of predetermined angle of rotation.
3. The radial translation clutch assembly system as claimed in claim 1, wherein said cam is guided in said cam link to radially translate said torque to said gearbox output shaft.
4. The radial translation clutch assembly system as claimed in claim 1, wherein said clutch operation integrated into said gearbox and adapted to decouple said torque from said gearbox output shaft to delivers said torque to at least one external charging member, on completion of at least one charging cycle.
5. The radial translation clutch assembly system as claimed in claim 1, wherein said cam interacts, using compression spring forces, with said ratchet on said gearbox output shaft to transmit said torque and disengages to achieve mechanical override.
6. The radial translation clutch assembly system as claimed in claim 1 and 4, wherein said mechanical override is provided so that said external member limits within said predetermined degree of rotation and completes said charging operation.
7. A radial translation clutch apparatus to achieve a mechanical cut-off between gears of at least one gearbox and at least one charging shaft when at least one spring is completely charged in switchgears, said radial translation clutch apparatus comprising:
at least one gearbox base plate (11), at least one gearbox output shaft (12), at least one ratchet (13), at least one cam link (14), at least one cam (15), at least one cutoff springs (161, 162), and at least one roller (17), WHEREIN
said cam link is adapted to achieve a linear translation of said cam in radial direction of gearbox output shaft (12), to allow positive engagement and/or disengagement from at least one teeth of said ratchet; and
said cam is adapted to receive an input force (torque) from said compression springs and achieve a torque transmission clutch function.
8. The radial translation clutch apparatus as claimed in claim 7, wherein said cam interacts with said ratchet using said input force (torque) from said compression spring on said gearbox output shaft to transmit said torque and disengage to achieve said mechanical override on completion of predetermined angle of rotation.
9. The radial translation clutch apparatus as claimed in claim 7, wherein said cam is guided in said cam link to radially translate said torque to said gearbox output shaft.
10. The radial translation clutch apparatus as claimed in claim 7, wherein said clutch operation integrated into said gearbox and adapted to decouple said torque from said gearbox output shaft to delivers said torque to at least one external charging member, on completion of at least one charging cycle.
11. The radial translation clutch apparatus as claimed in claim 7, wherein said cam interacts, using compression spring forces, with said ratchet on said gearbox output shaft to transmit said torque and disengages to achieve mechanical override.
12. The radial translation clutch apparatus as claimed in claim 7 and 10, wherein said mechanical override is provided so that said external member limits within said predetermined degree of rotation and completes said charging operation.
13. A method, to achieve a mechanical cut-off between gears of at least one gearbox and at least one charging shaft once at least one spring is completely charged fully, using a radial translation clutch assembly system/ a radial translation clutch apparatus, in switchgears, said method comprising:
providing, using at least one cam link of said radial translation clutch assembly system/ said radial translation clutch apparatus, a linear translation of at least one cam in radial direction of gearbox output shaft (12); and
allowing, due to said radial translation, a positive engagement and/or disengagement of said cam from at least one teeth of at least one ratchet of said radial translation clutch assembly system/ said radial translation clutch apparatus to achieve mechanical cut-off.
14. The method as claimed in claims 13, comprises receiving, by said cam from at least one compression spring of said radial translation clutch assembly system/ said radial translation clutch apparatus, an input force (torque).
15. The method as claimed in claims 13, comprises translating radially, by said cam guided by said cam link, said torque to said gearbox output shaft thereby achieving a torque transmission clutch function.