AU2008201424B2

AU2008201424B2 - Operating device of an electrical protection apparatus and electrical protection apparatus comprising same

Info

Publication number: AU2008201424B2
Application number: AU2008201424A
Authority: AU
Inventors: Yves Belin
Original assignee: Schneider Electric Industries SAS
Current assignee: Schneider Electric Industries SAS
Priority date: 2007-03-29
Filing date: 2008-03-28
Publication date: 2011-11-10
Anticipated expiration: 2028-03-28
Also published as: EP1975971B1; FR2914485B1; CN101276710B; MA29834B1; EA200800721A1; FR2914485A1; CN101276710A; BRPI0800942A2; EP1975971A1; AU2008201424A1; EA014194B1; ES2390081T3; AR067292A1

Abstract

OPERATING DEVICE OF AN ELECTRICAL PROTECTION APPARATUS AND 5 ELECTRICAL PROTECTION APPARATUS COMPRISING SAME. The present invention relates to an operating device of an electrical protection apparatus housed in an insulating case (I) containing a pair of stationary (5) and movable (4) contacts, said movable contact (4) being able to be actuated either manually by means of a 10 handle (6) or automatically, comprising a transmission rod (10) coupled to the handle (6), a support device (3) of the movable contact (4) comprising a plate (15) mounted rotating on a pivot (3 1) and having a breakable mechanical link with the transmission rod (10), and a trip lever (16) operated by a trip device to cause breaking of the mechanical link resulting in automatic tripping of the mechanism independently from the handle (6) and separation of 15 the contacts (4,5) in the event of a fault occurring, the breakable mechanical link being formed by a retaining notch of the trip lever (16) operating in conjunction with a latch (19) mounted swivelling on a pin (20) of the plate, breaking of the mechanical link corresponding to unlatching of the latch. This device is characterized in that the transmission rod (10), in the latching position of the latch, presses on the plate (15) and on 20 the latch (19), the relative positions of the two bearing surfaces respectively of the plate and of the latch and the ratio of the two leverages enabling the force of the rod on the trip lever to be reduced being chosen such that the force applied to the latch is lower than that applied to the plate. (Figure 1) (0 Oo LO N Cf) LO co 0 n n r 0) LO

Description

Pool Section 29 Regulation 3.2(2) AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: Operating device of an electrical protection apparatus and electrical protection apparatus comprising same The following statement is a full description of this invention, including the best method of performing it known to us: P11IABAU/1207 1 OPERATING DEVICE OF AN ELECTRICAL PROTECTION APPARATUS AND ELECTRICAL PROTECTION APPARATUS COMPRISING SAME. BACKGROUND 5 Patent FR 2 589 627 is known wherein an operating device of an electrical protection apparatus comprises a transmission rod which operates in conjunction with a plate acting upon a trip bar. In this device, the force of the mechanism is taken up 2/3 on the plate and 1/3 on the trip bar. There is no mechanical advantage effect reducing the forces involved. 10 Patent FR 2 616 583 describes an operating mechanism of a miniature electrical circuit breaker, including an assembly comprising a transmission rod, latch, and trip lever forming a gearing-down stage enabling the tripping force to be reduced. In this mechanism, the force of the rod exerts a torque on the latch. This geometry does not enable optimization to further reduce the latching force for reasons of size of the 15 mechanism in relation to the standard size of the modular circuit breaker pole-units. Consequently, the size of the magnetic and thermal protection devices cannot be further reduced. This limits the performances of the circuit breakers on account of the temperature rises produced by these devices. 20 It would be desirable to provide an operating device for an electrical apparatus whereby the performances of this apparatus can be improved. SUMMARY OF THE PRESENT INVENTION In light of the above, according to an aspect of the present invention, there is provided an 25 operating device of an electrical protection apparatus housed in an insulating case containing a pair of stationary and movable contacts, said movable contact being able to be actuated either manually by means of a handle or automatically, including - a transmission rod coupled to the handle, - a support device of the movable contact comprising a support plate mounted rotating on 30 a pivot and having a breakable mechanical link with the transmission rod, and 2 - a trip lever controlled by a trip device to break the mechanical link in the event of a fault occurring, resulting in automatic tripping of the mechanism independently of the handle and separation of the contacts, - the breakable mechanical link being formed by a retaining notch of the trip lever 5 operating in conjunction with a latch mounted swivelling on a pin of the plate, breaking of the mechanical link corresponding to unlatching of the latch, wherein the transmission rod, in the latching position of the latch, presses on the plate and on the latch, the relative positions of the two bearing surfaces respectively of the plate and of the latch and a ratio of the two leverages enabling the force of the rod on the trip lever 10 to be reduced, the ratio being chosen such that the force applied to the latch is lower than that applied to the plate. According to a particular feature, the relative positions of the two bearing surfaces and the ratio of the two leverages are chosen such that the force applied to the latch is about seven 15 times less than that applied to the plate. According to another particular feature, the latch and trip lever are made in a reduced thickness so as to enable an anti-pollution shield to be accommodated fitted between the rod and the latching zone between the latch and trip lever. 20 According to another feature, the latch is made of cut metal plate or of plastic, According to another feature, the latch and plate both include an opening designed to allow the plate to rotate when automatic tripping takes place, whereas the rod is blocked 25 in the closed position of the contacts by the handle. According to another feature, the plate also includes an opening designed to guide the travel of the rod to its initial position pressing on the plate when the handle reverts to the open position of the contacts after automatic tripping. 30 According to another feature, this device includes a spring with two branches fixed on the lever, including a first branch designed to move the trip lever back to its initial position ready for latching after tripping has occurred and a second branch designed to move the 3 latch to a preferred position in which sufficient clearance is created between the latch and lever so as to facilitate latching of the latch on said bar after automatic tripping. It is a further object of the invention to provide an electrical protection apparatus 5 comprising an operating device comprising the above-mentioned features taken either alone or in combination. Comprises/comprising and grammatical variations thereof when used in this specification are to be taken to specify the presence of stated features, integers, steps or components or 10 groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. DETAILED DESCRIPTION Other advantages and features of the invention will become more clearly apparent from 15 the following detailed description which refers to the accompanying drawings given for example purposes only, and in which: - figure 1 is a partial plane view illustrating the inside of a circuit breaker equipped with an operating device according to a particular embodiment of the invention, in the open 20 position of the contacts and of the handle, - figure 2 is an identical view to the previous one, the device being in a position corresponding to beginning of closing of the contacts, 25 - figure 3 is an identical view to the previous ones, in a closed position of the contacts and handle and illustrating the anti-pollution shield, - figure 4 is an enlarged view of the previous figure more particularly illustrating the operating device in the closed position of the contacts and handle corresponding to the 30 previous figure, 3a - figure 5 is a partial plane view more particularly illustrating the operating device in a tripped position, the handle being held in a closed position, - figure 6 is an identical view to the previous ones, illustrating the operating device in the 5 same position as figure 5, but in addition illustrating the anti-pollution shield, - figure 7 is an identical view to figure 1, but in addition illustrating the anti-pollution shield.

4 In the figures, a miniature electrical circuit breaker with a moulded insulating case I can be seen comprising an operating device 2 according to the invention. This device comprises a support device 3 of movable contact 4, said movable contact 4 operating in conjunction with a stationary contact 5. 5 An opening 7 is provided in front panel 8 of the case for passage of a handle 6 mounted with limited pivoting on a pin 11 of the case between a closed position in which contacts 4,5 are closed and an open position corresponding to separation of contacts 4,5. Handle 6 is equipped with an internal base 9 coupled to a transmission rod 10 to form a toggle device the joint 12 of which device is eccentric with respect to fixed pin I I of handle 6. 10 Handle 6 is biased counterclockwise to the open position of the contacts by a return spring (not represented). Stationary contact 5 is secured to the body of the electromagnetic trip device 13. Movable contact 4 is fixed to support device 3 of movable contact 4, said support 3 being articulated on a pivot 14, rotary plate 15 being mounted rotating around a pivot 31. 15 A trip lever 16 operated by the electromagnetic trip device striker and the bimetal strip of the thermal trip device (not represented) or of an external auxiliary is mounted pivoting on a pin 17 borne by plate 15 with a predetermined offset with respect to above-mentioned pivot 14. 20 A breakable mechanical link is arranged between transmission rod 10 and drive plate 15 of support device 3 of movable contact 4. In the latched position, the link enables manual control of the mechanism via handle 6. Movement of trip lever 16 to the tripped position due to the action of the trip devices causes momentary breaking of the mechanical link resulting in automatic tripping of the 25 mechanism independently from handle 6. Trip lever 16 is associated with a return spring 27 designed to perform automatic re-establishment of the mechanical link when handle 6 is actuated to the open position following tripping of the mechanism on a fault. The breakable mechanical link comprises a latch 19 pivotally mounted on a pin 20 of plate 15. Opposite this pin, nose 21 (fig.4) of latch 19 operates in the latched position of the link 30 in conjunction with a retaining notch 22 (fig.4) situated on the arm of trip lever 16. Transmission rod 10 is coupled to latch 19 and to plate 15 at an articulation point 23 that is able to move when tripping takes place in two consecutive openings 24 and 26 of plate 15.

5 This articulation point 23 is situated between articulation pin 20 (fig.3) of latch 19 on the plate and nose 21 (fig.4) of latch. The link constitutes a gearing-down stage in the kinematic chain of the mechanism, reducing the tripping force provided by the magneto thermal trip device. 5 Latch 19 also comprises a kidney-shaped or V-shaped opening 25 which, with openings 24 and 26 of plate, are designed to enable rotation of contact support plate 15 when tripping takes place, whereas rod 10 is blocked by handle 6 itself held in the closed position of the contacts. Opening 26 provided in plate 15 also enables the travel of the rod to be guided when the 10 handle returns to the open position of the contacts after tripping. The two openings 24,26 of plate 15 extend with respect to one another in such a way as to form a V. A polarization spring 27 with two branches 28,29 is fitted round pin 17 on lever 16. One 28 of the branches is designed to return trip lever 16 to its initial position whereas the other branch 29 polarizes latch 19 in a preferred position selected such as to create sufficient 15 clearance between lever 16 and latch 19 to enable latching. A shield 30 (figs.3, 6 and 7) integrated in trip lever covers the latching zone of trip lever 16 with latch 19. This shield is fitted between the rod and the latching zone of the latch and protects the latching zone from projections due to breaking. 20 Operation of the device will be described hereafter with reference to the figures. In figure 1, the operating device is in a position in which the contacts are open, the handle being in the open position. When handle 6 is actuated to perform closing of the contacts (fig.2), it moves rod 10 which then presses against plate 15 and latch 19 (fig.2). Latch 19 is latched on the trip bar (or 25 lever). Rod 10 pressing on plate 15 and on latch 19 makes the plate pivot around its pin 31 until contacts 4,5 close. The rod continues its travel until it passes the dead point of the toggle formed by the handle and rod. Then the mechanism takes the equilibrium position which keeps the contacts 30 closed as represented in figure 3 and 4. To open contacts 4,5 manually, handle 6 is actuated until it passes the dead point of the toggle in the opposite direction. The mechanism then reaches the equilibrium position, 6 with the contacts open, when the handle reaches the end of its travel, a position represented in figure 1. When the contacts are closed and the trip bar is actuated, latch 19 is unlatched but handle 6 does not return straight away to its open position. 5 The equilibrium of the forces exerted by rod 10 on the mechanism is broken. Plate 15 rotates around its pin 3 1 and opens the contacts, a position represented in figures 5 and 6. Opening 25 made inside latch 19 enables the latch to rotate around pin 20, and this opening 25 of the latch in conjunction with openings 24,26 of plate 15 allow the plate to rotate, the handle still being held in the position where the contacts are closed. 10 Then the spring of the handle moves the latter to the open contacts position and the rod moves the latch to the initial position as represented in figure 7. Spring 27 polarizing the latch and resetting the bar moves them to a position wherein latching of the latch can be performed on the bar when the handle is actuated to close the contacts. Openings 24,26 provided in plate 15 participate in guiding rod 10 so as to move the latter to a position in 15 which it is pressing on the plate. Thus, according to the invention, in the normal operating position of the electric circuit without a fault in the circuit, the rod presses on the contact support plate and on the latching match, the relative positions of the two bearing surfaces and the ratio of leverages X and Y being optimized so that the force latching the latch is reduced to the strict 20 minimum. The system thereby comprises two gearing-down stages. According to the first stage, the force of the mechanism is to a large extent taken up on the plate and to a small extent on the latch. According to the second stage, by leverage means on the latch, the force is reduced or geared down on the trip lever. 25 The force necessary for unlatching can thereby be reduced to a lower value than the solutions of the prior art. A reduction of the size of the products is achieved according to the invention, while at the same time preserving or increasing the performances of the device due to the fact that the size of the magnetic and thermal protection devices can be reduced. The heat given off by 30 the thermal protection devices is thereby reduced. Operation of the magnetic trip devices is quicker and better as the dynamic stresses are lower.

7 Reducing the latching force enables the bearing surface of the latch on the bar and therefore the thickness of the latch and trip bar to be reduced. Reducing the latching force also means that the latch can be made of cut metal plate as it is possible to make the latch from a thin metal plate. The small thickness of the latch and bar 5 enables an anti-pollution shield to be fitted between the rod on the one hand and the latching zone between the latch and bar on the other hand. It should also be noted that due to the presence of the polarizing spring, the chains of dimensions enabling the latch to be latched onto the bar are simplified. A single spring is therefore used to perform the two functions, i.e. re-initialization of the 10 bar and creation of a latching clearance. Likewise, due to the presence of this shield, the latching zone is not liable to be damaged by pollution due to breaking. The circuit breaker performances are preserved over time. The invention applies to any electrical apparatus comprising a mechanism of the above mentioned type, such as a circuit breaker, switch, differential switch, disconnecting switch, 15 auxiliary contacts including modular products etc..... Naturally the invention is not limited to the embodiments described and illustrated which have been given for example purposes only. 20 On the contrary, the invention encompasses all the technical equivalents of the means described as well as combinations thereof if the latter are performed according to the spirit of the invention.

Claims

1. An operating device of an electrical protection apparatus housed in an insulating case containing a pair of stationary and movable contacts, said movable contact being able to be actuated either manually by means of a handle or automatically, including 5 - a transmission rod coupled to the handle, - a support device of the movable contact comprising a support plate mounted rotating on a pivot and having a breakable mechanical link with the transmission rod, and - a trip lever controlled by a trip device to break the mechanical link in the event of a fault occurring, resulting in automatic tripping of the mechanism independently of the handle 10 and separation of the contacts, - the breakable mechanical link being formed by a retaining notch of the trip lever operating in conjunction with a latch mounted swivelling on a pin of the plate, breaking of the mechanical link corresponding to unlatching of the latch, wherein the transmission rod, in the latching position of the latch, presses on the plate and 15 on the latch, the relative positions of the two bearing surfaces respectively of the plate and of the latch and a ratio of the two leverages enabling the force of the rod on the trip lever to be reduced, the ratio being chosen such that the force applied to the latch is lower than that applied to the plate.

2. The device according to claim 1, wherein the relative positions of the two bearing 20 surfaces and the ratio of the two leverages are chosen such that the force applied to the latch is about seven times less than that applied to the plate.

3. The device according to claim 1 or 2, wherein the latch and trip lever are made in a reduced thickness so as to enable an anti-pollution shield to be accommodated fitted between the rod and the latching zone between the latch and trip lever. 25

4. The device according to any one of claims I to 3, wherein the latch is made of cut metal plate or of plastic.

5. The device according to any one of claims 1 to 4, wherein the latch and plate both include an opening designed to allow the plate to rotate when automatic tripping takes place, whereas the rod is blocked in the closed position of the contacts by the handle. 9

6. The device according to any one of the foregoing claims, wherein the plate also includes an opening designed to guide the travel of the rod to its initial position pressing on the plate when the handle reverts to the open position of the contacts after automatic tripping. 5

7. The device according to claim 5, wherein the opening of the latch is V-shaped.

8. The device according to claims 5 and 6, wherein the opening provided in the plate is formed by two openings of oblong shape forming a V.

9. The device according to any one of the foregoing claims, includes a spring with two branches fixed on the lever, comprising a first branch designed to move the lever 10 back to its initial position ready for latching after tripping has occurred and a second branch designed to move the latch to a preferred position in which sufficient clearance is created between the latch and lever so as to facilitate latching of the latch on said bar after automatic tripping.

10. The device according to any one of claims 3 to 5, wherein said shield is moulded 15 with the trip lever.

11. An electrical switchgear apparatus comprising an operating device according to any one of the foregoing claims.

12. An operating device of an electrical protection apparatus, substantially as herein described with reference to the drawings. 20

13. An electrical switchgear apparatus, substantially as herein described with reference to the drawings. SCHNEIDER ELECTRIC INDUSTRIES SAS WATERMARK PATENT & TRADE MARK ATTORNEYS P30018AU00