US3371178A

US3371178A - Linkage mechanism for circuit breakers

Info

Publication number: US3371178A
Application number: US536388A
Authority: US
Inventors: Lallemand Marcel
Original assignee: CONTINENTALE AND GARNER SA
Current assignee: CONTINENTALE AND GARNER SA
Priority date: 1966-03-22
Filing date: 1966-03-22
Publication date: 1968-02-27
Anticipated expiration: 1985-02-27

Description

Feb. 27, 1968 M. LALLEMAND 3,371,178

LINKAGE MECHANISM FOR CIRCUIT BREAKERS Filed March 22, 1966 v 3 Sheets-Sheet 1 Feb. 27, 1968 M. LALLEMAND 3,371,178

LINKAGE MECHANISM FOR CIRCUIT BREAKERS Filed March 22, 1966 3 Sheets-Sheet 2 Feb. 27, 1968 M. LALLEMAND 3,371,178

LINKAGE MECHANISM FOR CIRCUIT BREAKERS Filed March 22. 1966 5 Sheets-Sheet 5 United States Patent ice 3,371,178 LINKAGE MECHANISM FOR CIRCUIT BREAKERS Marcel Lallemand, Argenteuil, France, assignor to Societe Anonyme dite: Continentale & Garner, Paris, France, a French company Filed Mar. 22, 1966, Ser. No. 536,388 8 Claims. (Cl. 200-153) ABSTRACT OF THE DISCLOSURE A mechanism for a circuit breaker which is of small dimensions, especially in thickness, which gives complete protection. against overloads and short-circuits. One of two pivotally connected links is itself pivoted at a fixed point, the other link having a pin slidably engaged in a pivotally mounted slide, the pin being connected to a third link which has a second pin slidably mounted in a fixed slide having an elbow and an operating member is adapted to move the second pin in the second slide into the elbow portion to lock the mechanism so that a movable contact connected with the first and second links bridges the fixed contacts to close the circuit.

The present invention concerns an operating mechanism for a circuit breaker or the like.

Circuit breakers are known which comprise an operating and locking mechanism which, when an operating button is pressed, and in the absence of a fault, maintains a movable contact element or elements of the circuit breaker in engagement with fixed contacts and, locks the operating member in its closed position.

The subject of the present invention is an operating mechanism for a circuit breaker or the like, which has a reduced number of elements and which is relatively simple and of a reduced size.

A mechanism in accordance with the invention comprises two links which are hinged with respect to one another and of which one is pivotally mounted at a fixed point whilst the other carries a pin engaging a slide which is itself pivotally mounted at a fixed point, the moveable contact of the apparatus being connected to one of the links, preferably at the pivot common to the two links, with spring means tending to pivot the links so that they tend to move away from the fixed contacts, a catch or stop to prevent the slide from pivoting and means for displacing the pin in the slide and to maintain the pin in a locked position in which the moveable contact bridges the fixed contacts, characterized in that the means for displacing the pin in the slide and maintaining it in its locked position comprises a third link which is operatively connected to the pin and to an operating member of the linkage which is hinged on a further pin sliding in a fixed slide, this second slide comprising a portion which is essentially parallel to the position which the first slide occupies when it is prevented from pivoting and which is followed by an elbowed portion, the auxiliary pin at the end of the operating member engaging with the second slide.

The invention also envisages a circuit breaker or like device provided with a mechanism of the type defined 3,371,178 Patented Feb. 27, 1968 FIGS. 3 and 4 represent the mechanism after release;

FIG. 5 is an exploded perspective view of a circuit breaker;

FIG. 6 is a view in perspective of the support members of the circuit breaker looking in the direction of the arrow F of FIG. 5.

As represented schematically in FIGS. 1 to 4, the mechanism comprises a slide 1 which is carried by a lever 2 pivotally mounted at a fixed point 3. In front of the end of the slide 1 away from the pivot 3 there is, in the absence of an overload, a retractable stop 4 which is pivotally mounted at 5.

A pin 6 engages the slide 1, on which are pivoted two links 7 and 8. The link 7 carries a pin 9 at its end op-. posite the pin 6, which engages a fixed slide 10, the latter having an elbow 10a. The link 8 is connected by pivot 11 to a link 12 which is pivoted at one end at a fixed point 13. A spiral pring 14, tends to rotate this link 12 in the direction indicated by the arrow 15. The angle formed by the two links 7 and 8 must be less than and preferably less than 15; in fact if this angle is greater than 90 the link 7 would be more or less diametrically opposite the one shown, which would substantially increase the height of the mechanism.

On the pivot 11 is hinged a link 16 which carries a movable contact 17 adapted to bridge the fixed contacts 18a and 18b; finally, an operative member 19, acted upon by a return spring'41, permits the displacement of the pin 9 in the slide 10. This pin is normally returned to the upper part of the slide 10 by the action of the spring 41 on the lever 19.

The mechanism functions in the following manner. At rest (FIG. 1), the spring 14 tends to displace the pivot 11 and the link 8 upwardly, the mechanism being assumed to be vertical and to occupy the position shown in the drawings; the moveable contact 17 is thus remote from the fixed contacts 18a and 18b. The movement of the pin 6 is limited by the link 7, the pin 9 of which rests against the base of the slide 11). The movement of the pin 11 is limited by the contact 17 which rests against the casing of the apparatus 56a and 56b. The arrangement of the parts in the rest position is such that a space 1 exists between the upper part of the slide 1 and the stop the lever 12 against the action of the spring 14; link 16 applies the moveable contact 17 to the fixed contacts 18a and 18b.

At the end of the movement, the pin 9 moves into the elbow part 16a of the slide under the effect of the couple, with respect to the pin 6, of the resistance of the forces P and T, P being the force exerted on the operating member 19 and T the force exerted on the pin 9 by link 7. The mechanism is now in its locked position (FIG. 2). A spring connecting member 21 is provided between the moveable contact 17 and the pivot 11 to ensure a balanced pressure on the fixed contacts 18a and 181). To provide an improved locking effect a spring can be added to displace pin 9 downwardly towards the base of the elbow part 10a of the slide 10; in the drawings this is shown as a leaf spring 22 one end of which is fixed, the other bearing on an extension 23 of the link 7. A stop 24a limits the displacement of their free end.

Under the elfect of the spring 14-, the pin 6 exerts on the slide 1 a force along the direction of the link 8. Consequently, when the stop 4 is tripped by an overload, the slide 1 pivots in the direction of the arrow at the same time, the pin 6 moves upwardly in the slide. This movement frees the pivot 11 which moves up under the action of a spring 14 bringing the moveable contact 17 with it; at the same time the link 7 moves round its pivot 9 until its extension 23 meets the stop 24b (FIG. 3). From this position, the link 7 pivots around the point of contact of its extension 23 with fulcrum 2411, which disengages the pin 9 from the elbowed part 10a of the slide 10 and frees the operating member 19 (FIG. 4).

From the drawings it can be seen that the positions of the link 7 with its extension 23 and of the leaf spring 22 is such that this spring has no action on the pin 9, as this pin is disengaged from the elbowed part 10a. The operating 19 moves upward under the action of its return spring 41 and brings the slide 1 back into its initial position (FIG. 1). The mechanism is ready to be reoperated when the overload has disappeared.

If the operating member is depressed when the stop 4 is not in its normal position, displacement of the pin 9 only effects a pivoting motion of the slide 1, the pivot 11 and the contact 17 remaining immobile. The circuit therefore cannot be closed. FIGS. 5 and 6 show a circuit breaker provided with a mechanism of the type described above.

The elements of this mechanism are mounted in two support members and 26 connected one to the other by bolts, the assembly being enclosed in a casing formed from two

halves

27 and 28. The fixed parts of the mechanism, in particular the pivots 3, 5 and 13, the leaf spring 22 and the stop 24a and fulcrum 24b, are carried by the

members

25 and 26; extensions 3' and 5' for the pivots 3 and 5 can also be seen on the member 26. The operating member 19 passes between the two

elements

25 and 26 and carries, at its narrow end, a slot 29 for the pin 26; the operating member pivots on the pin 9. This member is connected to a press button 30 which is in contact with a further press button 31, the cross section of the two buttons being circular. The two buttons are slidingly mounted in a fixing 32 which is externally threaded and carries, at its narrow end, feet 33 engaging with the

shelves

27 and 28; these carry internal studs 34 which engage in holes 35 provided in the feet. Fins 19a of the operating member 19 are horizontally bent and spaced in the housing of the button 30 so that, when the button 30 is depressed the interlocking of the mechanism is effected as indicated previously. The upper face of the button 31 is under projection of the button 30. The retractable button is extended above its pivot 5 by a fork 4a which is positioned with its back to the foot 36a of a disengaging bar 36; this latter is moveably mounted in the member 26, parallel to the direction of a displacement of the buttons 30 and 31, and comprises a horizontal flap 36b disposed in the track of the button 31. The depression of this latter button has the effect of displacing the bar 36 downwardly, which, in pivoting the abutment 4a, frees the slide 1 and ensures its disengagement. Springs 37 and 38 tend to draw back the bar 36 into its upper position, and the abutment 36 into the position in which it is immobile on the slide 1.

The button 31 comprises an extension 39 which passes through an opening 40 of the member 19 which is mounted in a recess of the button 30. This extension has a boss 39a at its lower end which serves to guide a return spring 41 bearing against the horizontal upper faces of the

members

25 and 26. This spring maintains the button 31 in engagement with the button 30; it also tends to displace the member 19 with its pin 9 upwardly, this movement being limited by engagement of the pin 9 with the upper edge of the slide 10.

In one form, the circuit breaker comprises two entry terminals 4212-4212 and two outlets 43a and 43b. The terminals 42a and 4312 form a bridge between the fixed contacts 18a and 18b. The two terminals 42b and 43b are connected to one another by a conductor 44, a winding 45 provided with a core 46, a holding strip 47 and a conductor 48; the complete circuit is totally isolated electrically from the principal contacts controlled by the mechanism. In another form this control circuit is in series with the main contacts; in this case, the terminals 42a and 421) are omitted and the contact 18a is directly connected to the winding 45 by the connection 44. The strip 47 is fixed to the end of a bimetal strip 49 which serves to compensate for the ambient temperature and is mounted in a reverse sense to the strip 47; this strip 49 is itself fixed to the support member 26 by means of a stirrup 56, the legs of which can be spaced apart to any required degree by the regulating screw 51. The free end of the strip 47 is fixed to a plate 52 which can slide in the member 26. The interior edge of this plate is in the proximity of a projection 4b integral with the fork 4a. The strip 47 is mounted so that deformation under the effect of a rise in temperature of the outer edge of the plate 52 and of the projection 4b, are drawn together; it can be seen that, if the rise of temperature is sufficient, that is to say if the current through the circuit breaker exceeds a given value, plate 52 pushes back the projection 41; which pivots the stop 4 and opens the circuit breaker. The tripping current can be set by movement of the screw 51.

A magnetic plate 53 is mounted on the pivot 54 provided on the outer face of the member 26 and on the inner face of the half shell 28. This plate comprises a foot 53a which engages in a slot 55 provided in the disengaging bar 36. When this bar is in its upper position, in the absence of an overload, the lower edge of the slot 55 maintains the foot 53a in a position in which the free end of the magnetic plate is remote from the core 46.

If a short circuit is produced in the circuit controlled by the circuit breaker, the magnetic field in the winding 45 reaches a value such that the core 46 attracts the plate 53 against the action of the spring 37 which upwardly displaces the bar of the disconnector 36 and ensures the opening of the circuit breaker.

It can be seen from the preceding description that the circuit breaker, which is of small dimensions especially thickness, gives complete protection against short-circuits.

I claim:

1. An operating mechanism for a circuit breaker having a movable contact and fixed contacts comprising, a first link pivotally mounted to a fixed point, a second link pivotally connected to said first link, one of said links being operatively connected with said moveable contact, a pivotably mounted first slide, a first pin positioned on said second link and slidably engaged in said first slide, spring means urging said links to pivot away from said fixed contacts, a retractable stop adapted to prevent said slide from pivoting, a third link connected to said first pin and having a second pin, an operating member connected with said second pin, a second slide having a portion which is essentially parallel with respect to said first slide when said first slide is prevented from pivoting by said stop and an elbow portion, said second pin being slidably engaged in said second slide.

2. The mechanism defined in claim 1 wherein said third link is hinged on said second pin.

3. The mechanism defined in claim 1, wherein said operating member is pivotally mounted on said second pin.

4. The mechanism defined in claim 1 further comprising a second spring urging said second pin into said elbow portion.

5. The mechanism defined in claim 1 further comprising a fulcrum and an extension on said third link which pivots about said fulcrum when said retractable stop is retracted to disengage said second pin from said elbow.

6. The mechanism defined in claim 4 wherein said extension abuts said second spring as said second pin References Cited slides through said second slide while said retractable UNITED STATES PATENTS stop is in an unretracted position so that said second pin 2 911 494 11/1959 Rigert 200153.9 XR

is forced 1nto sa1d elbow but does not abut sa1d extension when said retractable stop is retracted. 5 312511240 5/1966 Fredenck 20O453-9 XR 7. The mechanism defined in claim 6 wherein said FO G PA second and third links include an angle which is less 1234141 10/1960 France than ninety degrees.

8. The mechanism defined in claim 7 wherein said angle ROBERT SCHAEFER, Primary Examineris less than fifteen degrees. 10 H. BURKS, Assistant Examiner.