Title of Invention

AN OPERATING MECHANISM OF AN ELECTRICAL CIRCUIT BREAKER WITH AN INSULATING CASE

Abstract

An operating mechanism of an electrical circuit breaker with an insulating case housing a pair of stationary and movable contacts, said movable contact being supported by a contact arm actuated between the closed position and the open position by the mechanism, which comprises: a handle equipped with a first means for transmission of a position and/or operation information, a drive plate for driving a support lever supporting the contact arm, said plate being mounted in rotation on a pivot to define a first angular travel a, a breakable mechanical link arranged between the plat and a rod coupled to the handle, said link being operated by a trip lever controlled by a trip component to bring about breaking of the mechanical link in the event of a fault occurring resulting in automatic tripping of the mechanism, and a second means for transmission arranged on the trip lever to transmit a power and/or operation information, characterized in that the pivoting spindle of the contact arm is securely affixed to the case and passes through an opening of the plate with preset offset with respect to the pivot, and that the plate is provided with a drive stop separated respectively from the spindle of the contact arm by a first radius (R1), and from the pivot by a second radius (R2), the difference of length of the radii (R1, R2) allowing an amplified opening of the contact arm, which is greater than the angular travel a of the plate.

Full Text

A CIRCUIT BREAKER OPERATING MECHANISM WITH A WIDE OPENING ANGLE The invention relates to an operating mechanism of an electrical circuit breaker with an insulating case housing a pair of stationary and movable contacts, said movable contact being supported by a contact arm actuated between the closed position and the open position by the mechanism, which comprises : - a handle equipped with a first means for transmission of a position and/or operation information, - a drive plate for driving a support lever supporting the contact arm, said plate being mounted in rotation on a pivot to define a first angular travel a, - a breakable mechanical link arranged between the plate and a rod coupled to the handle, said link being operated by a trip lever controlled by a trip component to bring about breaking of the mechanical link in the event of a fault occurring resulting in automatic tripping of the mechanism, - and a second means for transmission arranged on the trip lever to transmit a power and/or operation information. A mechanism of a circuit breaker D of the prior art is illustrated in figures l to 3. The mechanism 10 comprises a support lever 11 supporting the movable contact arm 12 which is articulated on the pivot 14 of the rotary drive plate 16. The trip lever 18 is also articulated on the plate 16, but on a spindle offset with respect to the pivot 14. The connecting rod between the handle 20 and the latching hook of the plate 16 is not represented for the sake of clarity. The handle 20 and trip lever 18 respectively comprise a first means of transmission 22 and a second means of transmission 24 able to transmit position and power information to the auxiliary modules A. The auxiliary modules A may be trip or signalling modules, which can be fitted onto a large side face of the case 26 of the circuit breaker D. In figure 2, the first means of transmission 22 of the handle 20 of the circuit breaker D is mechanically linked to the handle 28 of the auxiliary module A by a first operating link 30. The second means of transmission 24 is mechanically connected to the auxiliary A by a second operating link 32. The first operating link 30 serves the purpose of transmitting a signal indicating the dosed or open state of the circuit breaker D to the auxiliary A when the latter is constituted by a signalling module OF. The two-way second operating link 32 serves the purpose of transmitting in one direction a signal indicating tripping of the circuit breaker D to the auxiliary A when the latter is constituted by a fault signalling module SD, or of transmitting in the opposite direction a signal indicating a tripping order of the auxiliary module A, for example an earth leakage protection unit, to the circuit breaker D. Operation of a mechanism of this kind is described in detail in the document EP-A-295,158. When the contacts 34, 36 separate, a stop 38 of the rotary plate 16 drives the support lever 11 counterclockwise around the pivot 14. In the open position (figure 3), the opening angle ct of the movable contact arm 12 corresponds appreciably to the angular travel of the plate 16 after the clearance between the stop 38 and support lever 11 has been taken up. In order that the same auxiliary modules A can still be used, it is imperative when extending a circuit breaker range to respect the positioning and angular clearance of the means of transmission 22, 24 in the different operating states, notably closed,-open, and tripped. If the articulation of the support lever 11 is maintained on the pivot 14 of the plate 16, the opening angle rf of the movable contact 12 will remain constant. The dielectric strength of a circuit breaker of this kind, being directly proportional to the distance separating the contacts 34, 36 in the open state, would thereby be insufficient for a switchgear apparatus of high ratings. The object of the invention is to achieve a circuit breaker mechanism having an improved dielectric strength without modifying the kinematics of the means of transmission for fitting of auxiliary modules, regardless of whether the operating mode is manual or automatic. The mechanism according to the invention is characterized in that the pivoting spindle of the contact arm is securedly affixed to the case and passes through an opening of the plate with a preset offset with respect to the pivot, and that the plate is provided with a drive stop separated respectively from the spindle of the contact arm by a first radius, and from the pivot by a second radius, the difference of length of the radii allowing an amplified opening angle of the contact arm which is greater than the angular travel of the plate. The differential movement between the contact arm and the plate due to decentering of the pivoting spindle of the arm enables the insulation distance to be increased without the angular travel of the plate being modified, which remains suitable for fitting of standard auxiliaries. According to a feature of the invention, the opening for passage of the spindle through ttie plate presents an oblong shape, so as to exert a lever effect on the contact arm in the separation direction of the contacts. Accordingly the present invention provides an operating mechanism of an electrical circuit breaker with an insulating case housing a pair of stationary and movable contacts, said movable contact being supported by a contact arm actuated between the closed position and the open position by the mechanism, which comprises: a handle equipped with a first means for transmission of a position and/or operation information, a drive plate for driving a support lever supporting the contact aim, said plate being mounted in rotation on a pivot to define a first angul^" travel a, a breakable mechanical link arranged between the plat and a rod coupled to the handle, said link being operated by a trip lever controlled by a trip component to bring about breaking of the mechanical link in the event of a fault occurring resulting in automatic tripping of the mechanism, and a second means for transmission arranged on the trip lever to transmit a power and/or operation information, characterized in that the pivoting spindle of the contact arm is securedly affixed to the case and passes through an opening of the plate with preset offset with respect to the pivot, and iJiat the plate is provided with a drive stop separated respectively from the spindle of the contact arm by a first radius (Rl), and from the pivot by a second radius (R2), the difference of length of ttie radii (Rl, R2) allowing an amplified opening p of the contact arm, which is greater than the angular travel a of the plate. other advantages and features will become more ciearty apparent from the follovi/ing description of an illustrative embodiment of the invention given as a non-restrictive example only and represented in the accompanying drawings in which : - Figure 1 is a schematic elevational view of a circuit breaker mechanism of the prior art, the contacts being represented in the closed state, - Figure 2 shows, on a reduced scale, the association of the circuit breaker of figure 1 with an auxiliary module, notably a tripping or signalling module, - Figure 3 is an identical view to that of figure 1, with the contacts represented in the open state, - Figure 4 is a vertical sectional view of the operating mechanism according to the invention. - Figures 5 and 6 show respectively cross-sectional views along the lines 5-5 and 6-6 of figure 4, the mechanism being represented in the closed state of the contacts, - Figure 7 is an identical view to that of figure 6, the mechanism being represented in the open state of the contacts, - Figure 8 is a schematic view of the mechanism according to figure 6, after an attempt to perform manual opening following welding of the contacts, - Figure 9 is an identical view to that of figure 8, showing an alternative embodiment. With reference to figures 4 to 7, the same reference numbers will be used to designate identical parts to those of the mechanism of figures 1 to 3, The mechanism 40 is equipped with a movable contact arm 12 with a wide opening angle J3 obtained by means of decentering of the spindle 42 with respect to the pivot 14 of the drive plate 16. The double plate 18 is formed by a pair of elements 16a, 16b each having a pivot 14 engaged in a bearing 44a, 44b of the insulating case 46. The trip lever 18 is mounted with pivoting on a spindle 48 of the plate 16 and cooperates with a tripping component 50 operated by a blade 52 of the electromagnetic trip device 54, The second means of transmission 24 is arranged on the trip lever 18 which is designed, when a fault occurs, to interrupt the mechanical link between the plate 16 and the rod 56 coupled to the handle 20. This mechanical link is achieved by means of a latching hook 58 articulated on a spindle 60 of the plate 18. The pivoting spindle 42 of the movable contact arm 12 passes through an oblong opening 62 of the plate 16 and is supported in bearings arranged in the opposite faces of the case 46. The opening 62 of each element 16a, 16b of the plate 16 is offset with respect to the pivot 14 and to the spindle 48 of the articulation, the pivot 14 being located between the pivoting spindle 42 of the contact arm 12 and the movable contact 36. A first spring 64 for actuation of the plate 16 to the open position comprises a torsion spring surnDunding the pivot 14. One of the end strands of the spring 64 is secured on the plate 16 and the opposite strand is in engagement with a fixed stop of the case 46. A second spring 66 for contact pressure is arranged on a protrusion 68 of the support lever 11 and surrounds the pivoting spindle 42. This spring 66 allows a relative pivoting movement between the plate 18 and the support lever 11, and urges the latter to the closed position to provide a predetermined contact pressure with the stationary contact 34. The plate 16 is equipped with a drive stop 70 designed to come into engagement against a bearing surface 72 of the support lever 11 to move the latter to the open position. The radius R1 arranged between the spindle 42 of the contact arm 12 and the drive stop 70 is smaller than the radius R2 between the pivot 14 of the plate 16 and the same stop 70. Separation of the contacts 34, 36 takes place following movement of the plate 16 to the open position, which can be achieved manually by operation of the handle 20 or automatically following tripping after a fauit has been detected. In both cases, the drive stop 70 engages the bearing surface 72 of the support lever 11 and drives the iatter counterclockwise to the open position of the contacts 34, 36 (figure 7). The difference of length of the radii R1 and R2 conditions an amplified opening angle J5 of the contact arm 12, while the plate 16 performs a standard pivoting movement with a travel a corresponding to that of figure 3. The amplification effect of the opening movement of the contact arm 12 enables a larger insulation distance to be obtained, whereas the angle of rotation aiof the plate 16 remains suited to the kinematics of the means for transmission 22, 24 at the level of the handle 26 and of the trip lever 18. With reference to figure 8, when an attempt is made to open by means of the handle 20, the housing of the spindle 42 in the oblong aperture 62 of the case 46 causes a lever effect exerted on the movable contact arm 12, liable to cause tearing off of the contacts 34, 36 from a welded state of the latter at the point S. The pivoting spindle 42 is normally urged by the spring 66 towards the right-hand end of the oblong opening 62 From a welded state of the contacts 34, 36, movement of the handle 20 to the open position causes a slight raising movement of the contact arm 12 and movement of the spindle 42 to the left in the opening 62 from the initial position 0 to a first position 1. According to the alternative embodiment of figure 9, the inclination of the opening 62 enables a shearing effect to be obtained at the level of the welding S, in addition to the lever effect, following movement of the spindle 42 from the Initial position 0 to a second position 2, This shearing effect moreover causes sliding of the movable contact 36 with the stationary contact 34 enabling self-cleaning of the contacts. WE CLAIM 1. An operating mechanism of an electrical circuit breaker with an insulating case (46) housing a pair of stationary (34) and movable (36) contacts, said movable contact being supported by a contact arm (12) actuated between the closed position and the open position by the mechanism (40) which comprises : - a handle (20) equipped with a first means for transmission (22) of a position and/or operation information, - a drive plate (16) for driving a support lever (11) supporting the contact arm (12), said plate (16) being mounted in rotation on a pivot (14) to define a first angular travel a, - a breakable mechanical link arranged between the plate (16) and a rod (56) coupled to the handle (20), said link being operated by a trip lever (18) controlled by a trip component to bring about breaking of the mechanical link in the event of a fault occurring resulting in automatic tripping of the mechanism (40), - and a second means for transmission (24) arranged on the trip lever (18) to transmit a power and/or operation information, characterized in that the pivoting spindle (42) of the contact arm (12) is securedly affixed to the case (46) and passes through an opening (62) of the plate (16) with a preset offset with respect to the pivot (14), and that the plate (16) is provided with a drive stop (70) separated respectively from the spindle (42) of the contact arm (12) by a first radius (R1), and from the pivot (14) by a second radius (R2), the difference of length of the radii (R1, R2) allowing an amplified opening angle b of the contact arm (12), which is greater than the angular travel a of the plate (16). 2. The operating mechanism according to claim 1, characterized in that the opening (62) for passage of the spindle (42) through the plate (16) presents an oblong shape, so as to exert a lever effect on the contact arm (12) in the separation direction of the contacts (34, 36). 3. The operating mechanism according to claim 2, characterized in that the opening (62) in the plate (16) is inclined according to a predetermined direction, allowing an additional shearing effect suitable for self-cleaning of the contacts. 4. The operating mechanism according to one of the claims 1 to 3, characterized in that the pivot (14) of the plate (16) is situated between the pivoting spindle (42) of the contact arm (12) and the movable contact (36), and theft the articulation spindle (48) of the trip lever (18) is located on the plate (16). 5. An operating mechanism of an electrical circuit breaker, substantially as herein described, with reference to the accompanying drawings.

Documents:

531-mas-1997 abstract duplicate.pdf

531-mas-1997 abstract.pdf

531-mas-1997 claims duplicate.pdf

531-mas-1997 claims.pdf

531-mas-1997 correspondence others.pdf

531-mas-1997 correspondence po.pdf

531-mas-1997 description (complete) duplicate.pdf

531-mas-1997 description (complete).pdf

531-mas-1997 drawings duplicate.pdf

531-mas-1997 drawings.pdf

531-mas-1997 form-1.pdf

531-mas-1997 form-26.pdf

531-mas-1997 form-4.pdf

531-mas-1997 petition.pdf