US3239621A - Snap action switch - Google Patents

Description

March 8, 1966 B. DAUSSIN ETAL 3,239,621

SNAP ACTION SWITCH Filed June 29, 1964 4 Sheets-Sheet 1 March 8, 1966 B. DAUSSIN ETALSNAP ACTION SWITCH 4 Sheets-Sheet 2 Filed June 29, 1964 March 8, 1966 B. DAUSSIN ETAL 3,239,621

SNAP ACTION SWITCH Filed June 29. 1964 4 Sheets-Sheet 5 March 8, 1966 B.DAUSS1N ETALSNAP ACTION SWITCH 4 Sheets-Sheet 4 Filed June 29, 1964 FIG.7

FIG. 8

fZZ g %f United States Patent Ofiice 3,Z39,Zl Patented Mar. 8, 1966 3,239,621 SNAP ACT IGN SWITCH Bernard Daussin and Jean Granson, Saint-Quentin, and

Henry Baulier, Le Mans, France, assignors to Compagnie Generate dElectricite, Paris, France, a corporation of France Filed June 29, 1964, Ser. No. 378,509 Claims priority, application France, June 27, 1963, 939,583 19 Claims. (Cl. 200-68) The present invention relates to a snap action electric switch.

It is known to utilize elastic means, such as springs in circuit breakers and similar devices to provide a contact pressure between the contact points of the mobile parts and the corresponding stationary parts of the main circuits. There are also known switches in which the flow of current, due to particular arrangements of the main circuits, generates electrodynamic forces that provide a contact pressure additional to that which is due to the spring forces. Such switches are advantageous in that noticeably higher currents may be used than heretofore possible without risking an accidental opening of the switch.

In case only spring loaded switches are used to cause or interrupt a high intensity current flow, it is necessary that the circuit closing operation be carried out fast enough so that the springs will be sufficiently compressed and thus will exert an adequate pressure on the contacts before the current intensity reaches too high an instantaneous value. If this condition is not met, the current may cause a separation of the contacts before the full closing of the equipment. Consequently, arcing will occur between the contacts, causing, in general, well known damages.

A fast circuit closing operation is required even in case of switches where the pressure on the contacts is provided both by springs and by the electrodynamic effects created by the current flowing in the main circuits. It is essential that, before the current intensity reaches too high an instantaneous value, first, the springs should be sufiiciently compressed and secondly, the parts subjected to the electrodynamic etfects should be in a position that very nearly corresponds to the closed position of the switch. If this condition is not met, the operator may be unable to ensure the full closing of the switch resulting in possible damage to the equipment and harm to himself.

To ensure a sufficiently fast closing of the types of switches mentioned hereinbefore, the invention provides a snap action mechanism that eilectuates the closing of the switch with a suflicient speed regardless of how fast the operator himself actuates the switch.

The present invention relates to switch mechanisms for making and breaking high intensity currents, wherein the snap action during the closing operation may take place with a minimum of energy input; i.e. fast, snap action closing of the switch is ensured without the necessity to resort to ancillary energy storing devices associated with the switch actuator or the circuits.

According to a principal feature of the invention, there are provided restraining means for ensuring the sudden closing of the contacts by holding them back during the closing operation and releasing them only in the final phase thereof when the moving parts of the switch are very nearly in their closed position. During the closing operation, and before the stationary and mobile contact parts of the main circuits engage, the springs associated with these contact parts are already compressed with a force greater than that which will be necessary when the switch is fully closed. The contacting motion of the mobile parts of the main circuits with the corresponding stationary parts is caused by the surplus energy previously stored in the contact pressure springs. Thus, the speed of the contacting motion is independent not only of the speed the operator handles the switch, but also, in particular, of the speed at which the springs were compressed.

The invention may be advantageously practiced in switches where electrodynamic effects created by the cur rents flowing in them increase the pressure on the contacts. According to the invention the parts which are to be affected by the electrodynamic forces are thcmselves, in the final phase of the closing operation, disposed very near their final position and consequently, the switch mechanism, and particularly its lock, do not have to be exposed to force noticeably higher than those which are applied when the equipment is fully closed.

As it will become apparent from the ensuing detailed description, the closing of the switch is achieved by a continuous, unidirectional movement of the actuating handle.

The restraining means used for holding back the contacts during the closing operation have two additional important functions: on one hand, the contact parts are able to resist reclosing by accidental snap back during opening and, on the other hand, the restraining means permit the storage, in potential form, of the kinetic energy gained during the opening operation of the switch. This stored energy is utilized during the closing operation, thus making possible a substantial decrease in the external energy input. Consequently, the eifort to be delivered by the operator when the equipment is handoperated, or, in case the operation is carried out with the help of an ancillary energy source, the output of the electric or pneumatic actuating devices may be reduced in the same proportion.

The invention will be better understood in the light of the ensuing description of non limitative embodiments, taken in conjunction with the accompanying drawings.

To facilitate the description, the switches shown by Way of example have only one pole, provided with only one mobile part. It is to be understood that, within the scope of the invention, the switches may be of either the multi-pole or single-pole type and may comprise either one or several mobile parts for each pole.

FIGURE 1 is a plan view in fully open position of an embodiment according to the invention, in which the pressure on the contacts is provided only by springs;

FIGURE 2 is a view of the same embodiment in the last phase of the closing operation preceding the full closing;

FIGURE 3 is a View of the same embodiment in closed position;

FIGURE 4 is a view of the same embodiment at the beginning of the opening operation;

FIGURE 5 is a plan view in the fully open position of another embodiment in which the main circuits are arranged in such a Way that the elcctrodynamic effects arising from the current contributes to the pressure on the contacts;

FIGURE 6 is a view of the embodiment according to FIGURE 5 in the last phase of the closing operation preceding the full closing;

FIGURE 7 is a view of the embodiment according to FIGURE 5 in closed position and FIGURE 8 is a view of the embodiment according to FIGURE 5 at the beginning of the opening operation.

The switch shown in FIGURE 1 includes a stationaryconductive element 1 integral with a frame ormounting base 12 and fitted with a permanentcurrent contact 2 and burning-tip contact 3. There is further shown a mobileconductive contact element 4, provided with a permanent current contact 5- and a corresponding burning-tip contact 6. A stationaryconductive element 7, integral with theframe 12, is connected to thecontact element 4 by means of aflexible conductor 8. Thecontact element 4 is fixedly mounted on anelongated bracket 9, held in a cage by apivot pin 11. Thecage 10 is attached to theframe 12 by apivot pin 13. Between one end ofcage 10 andbracket 9 there is disposed aspring 14 adapted tourge parts 9 and 10 apart. In the position shown in FIGURE 1, thespring 14 is maintained in a compressed condition by a lever or restraining means 15 pivotable around apin 16 secured tocage 10. At oneend lever 15 is provided with aroller 17 rotating around apin 18 integral withlever 15.Roller 17 engages the heel-shaped portion of thebracket 9. Ayoke 19, secured to the back ofcage 10, carries apin 20 on which hinges an insulating connecting rod or linkage means 21, attached to the end of anarm 22 by means of apin 23. One end of an insulating connecting rod or release means 24 is attached topin 23. The other end of connecting-rod 24 is provided with aslot 25 which slideably receives apin 26 integral with thelever 15. Thearm 22 is keyed to an actuatingshaft 27 connected to an actuating mechanism such asoperating handle 28. There may further be provided a catch mechanism comprising ahook 29 securedto theshaft 27 and a detent 30. Attached to thehook 29 and to a stationary pin integral with the frame is atension spring 34 which exerts a return torque on theshaft 27 in the opening direction and urges thearm 22 against astop 36.

FIGURE 1 shows the switch at rest in a fully open position. During the opening operation bringing the switch to this position, thearm 22 pulled the connecting-rod 24 which, imparting a counter-clockwise motion to lever 15, caused theroller 17 to force itself into the heel-shaped portion ofbracket 9, resulting in a clock-wise rotation of the latter aboutpin 11. This motion, in turn, caused a recompression ofspring 14 which is maintained in this position as shown in FIGURE 1.

For starting the closing operation, the operator moves thelever 28 upwardly, causing a counter-clockwise rotation of actuatingshaft 27 andarm 22. Pushed by the connecting-rod 21, thecage 10, as it rotates around thestationary pin 13, brings thecontact element 4 closer to thestationary element 1.

FIGURE 2 shows the switch in the final phase of the closing operation, where thehook 29 is on the point of being engaged by the detent 30. Thecontact element 4 is still retracted and spaced from thestationary contact 1 due to the position ofroller 17 urgingcontact element 4 towardscage 10, compressingspring 14. It is seen from FIGURE 2, however, that during the closing operation therod 24 imparted a clock-wise rotation to lever 15, causingroller 17 to ride upwardly on the heel-shaped portion ofbracket 9 and assume an unstable equilibrium position. As the closing operation continues,release rod 24 causes a further clock-wise rotation oflever 15. As a result,roller 17 entirely clears the heel portion ofbracket 9. Thus,bracket 9 is free to pivot aboutpin 11, and, consequently,contact 4 will snap into its circuit-making position urged solely by thespring 14. At thistime hook 29 is engaged bydetent 30. The fully closed position of the switch is shown in FIGURE 3. It is noted that only thepermanent contacts 2 and 5 are pressed together byspring 14. It is thus seen that the contacting operation is instantaneous and the amount of pressure is at a predetermined value.

FIGURE 4 shows the switch at the beginning of the opening operation, following the release ofhook 29 bydetent 30, whilecage 10 has started its clock-wise open ing movement under the effect of the return-spring 34. In this beginning stage of the opening operation thepermanent contacts 2 and 5 are no longer in engagement; the current flows across the burning-tip contacts 3 and 6 pressed against one another. As the switch opening operation continues, the slotted connecting-rod 24 drives thelever 15 counter-clockwise, forcingroller 17 into its stable equilibrium position in the heel-shaped portion of thebracket 9. Thus,spring 14 is recompressed as it was described hereinbefore in connection with FIGURE 1. Since a substantial portion of the kinetic energy of the mobile parts is spent in completing the recompression of thespring 14 during the opening movement, the mobile assembly abuts thestop 36 with a very small kinetic energy. Consequently, the snap-back effect onarm 22 will be insignificant. Furthermore, whilelever 15 maintains thespring 14 compressed, thecontact element 4 remains spaced from thestationary element 1. Thus, the switch is adapted to resist effectively any recl-osing by accidental snap-back during the opening operation.

FIGURES 5, 6, 7 and 8 show another embodiment. The switch is shown in consecutive positions corresponding to those of the previous embodiment and the same reference numerals have been given to similar or corresponding parts.

Thecage 10 carrying themobile contact element 4 rotates around thestationary pin 13 and is driven by a connecting-rod 42, connected to thecage 1% and to thepart 4 by thepin 11. Further, the connecting-rod 42 is rotatable around apin 37 also linking the connecting orrelease rod 24 to alever 38.Lever 38 is pivotable around a stationary pin 45 The free end oflever 38 is connected to the insulating connecting-rod 21 by means of thepin 20.

The contact pressure and return-spring 41 abuts against astationary stop 39 and exerts its force directly against thecontact element 4. Thespring 41 is compressed between thestationary stop 39 andcontact element 4 by theroller 17 movable along the back side ofpart 4.

With reference to FIGURE 5, to start the closing operation of the switch, the operator moves handle 28 downwardly, liftingarm 22 from its abutting relationship withstop 36 and causing a counter-clockwise rotation oflever 38. Aslever 38 moves, the connecting-rod 42 causescontact element 4 to approach thestationary contact 1 againstspring 41. The final phase of the closing operation is depicted in FIGURE 6.Contact element 4 is still spaced fromelement 1 andhook 29 is about to engagedetent 30. Slottedrelease rod 24 causedroller 17 to assume an unstable equilibrium position. As the closing operation continues,release rod 24 causes a further clock-Wise rotation oflever 15. As a result,roller 17 swings over center and releasescontact element 4 which, urged byspring 41, pivots aboutpin 11 and snaps into its circuit making position as shown in FIGURE 7. At thistime hook 29 is engaged bydetent 30.

In the closed position (FIGURE 7), thespring 41, acting on thepart 4 presses thecontact 5 onto thecontact 2. The reaction of this force at thehinge point 11 is transmitted by the connecting-rod 42 to thelever 38. The major portion of the reaction is taken up by thepin 40 since the connecting-rod 42 and thelever 38 form a very small angle. The minor portion of this reaction is transmitted by the insulatingrod 21 to thearm 22 and to thehook 29. Consequently,detent 30 is at no time exposed to significant forces.

When an intense current flows through the switch, electrodynamic forces act on thestationary elements 1 and 7 and on themobile contact element 4.Stationary element 7 andcontact element 4 are shaped and disposed in such a manner that the forces below thepin 11 exceed by far those above it. The resultant of these forces coincides and thus enhances the eifect of thespring 41 in order to compensate the repulsive forces arising between thecontacts 2 and 5 due to the current flow. The reaction of the joint forces of thespring 41 and of the resultant of the electrodynamic forces on thepin 11 is taken up almost entirely by the connecting-rod 42, thelever 38 and thepin 40 secured to theframe 12. Hence, in case of high intensity current it is advantageous that, at the moment the contacts engage, theparts 42 and 38 define as small an Although only two embodiments of the invention have been depicted and described, it will be apparent that these embodiments are illustrative in nature and that a number of modifications in the apparatus and variations in its end use may be effected without departing from the spirit or scope of the invention as defined in the appended claims.

We claim:

1. A snap action electric switch comprising,

(a) a mounting base,

(b) cage means pivotally secured to said base and movable between a closed position and an open position,

(c) contact means pivotally secured to said cage means and adapted to assume a retracted open position and a circuit making triggered position,

(d) spring means for urging said contact means toward said triggered position,

(e) restraining means for maintaining said contact means in said retracted position against the force of said spring means as long as said cage means is in an open position,

(f) arm means adapted to impart a pivoting motion to said cage means, and

(g) releasing means actuated by said arm means and connected to said restraining means, said releasing means being adapted to trip said restraining means to permit said contact means to snap into said triggered position as said cage means pivots toward said closed position actuated by said arm means.

2. An electric switch as defined inclaim 1, including linkage means pivotally connected to said arm means and to said cage member and said restraining means being pivotally secured to said cage means.

3. Snap action switch as defined inclaim 1 wherein said arm means is pivotally secured to said mounting base.

4. A snap action electric switch comprising,

(a) a mounting base,

(b) a cage member pivotally secured to said base and movable between a closed position and an open position,

(c) a contact element pivotally secured to said cage member, and adapted to assume a retracted open position and a circuit making triggered position,

(d) spring means disposed between said contact element and said cage to urge said contact element toward said triggered position,

(e) restraining means pivotally secured to said cage member for maintaining said contact element in said retracted position against the force of said spring means when said cage member is in an open position,

(i) arm means pivotally secured to said base for imparting motion to said cage member,

(g) linkage means pivotally connected to said arm means and to said cage member, and

(h) releasing means actuated by said arm means and connected to said restraining means and adapted to trip said restraining means to permit said contact element to snap into said triggered position as said cage member pivots toward said closed position actuated by said arm means.

5. An electric switch as defined inclaim 4, wherein said contact element is secured at its mid portion to said cage member by a pivotal joint, said spring means and said restraining means being disposed on opposite sides of said pivotal joint.

6. An electric switch as defined inclaim 5, wherein said restraining means includes a lever pivotally secured at its mid portion to said cage member, one end of said lever being secured to said releasing means, the other end of said lever being adapted to engage a heel portion on said contact element to maintain the same in its said retracted position when said cage member is in an open position, said other end of said lever adapted to be disengaged from said heel portion by the force imparted to said lever by said releasing means to permit said contact element to turn about said pivotal joint and snap into said triggered position urged by said spring means as said cage member pivots toward said closed position actuated by said arm means.

7. An electric switch as defined inclaim 5, wherein said releasing means includes an elongated element pivot-a1- ly secured at one end to said arm means, the other end of said elon ated element being provided with a slot for slidably receiving the end of said lever distal from said heel portion.

3. A snap action electric switch comprising,

(a) a mounting base having at least one stop secured thereto,

(b) a cage member pivotally secured to said base and movable between a closed position and an open position,

(c) a contact element pivotally secured to said cage member and adapted to assume a retracted open position and a circuit making triggered position,

(d) spring means disposed between said contact element and said stop to urge said contact element to ward said triggered position and to urge said cage member toward said open position,

(e) restraining means pivotally secured to said cage member for maintaining said contact element in said retracted position against the force of said spring means when said cage member is in an open position,

(f) arm means pivotally secured to said base for imparting motion to said cage member,

(g) linkage means pivotally connected to said arm means and to said cage member, and

(h) releasing means actuated by said arm means and connected to said restraining means and adapted to trip said restraining means to permit said contact element to snap into said triggered position as said cage member pivots toward said closed position actuated by said arm means.

9. An electric switch as defined inclaim 8, wherein said contact element is secured at about its mid portion to said cage member by a pivotal joint, said spring means and said restraining means being disposed on the same side of said pivotal joint.

it). An electric switch as defined inclaim 9, wherein said restraining means includes a lever, one end of which is pivotally secured to said cage member, the other end of said lever is adapted to engage a heel portion on said contact element to maintain the same in its said retracted position when said cage member is in an open position, the mid portion of said lever being secured to said releasing means, said other end of said lever adapted to be disengaged from said heel portion by the force imparted to said lever by said releasing means to permit said contact element to turn about said pivotal joint and snap into said triggered position as said cage member pivots toward said closed position actuated by said arm means.

No references cited.

KATHLEEN H. CLAFFY, Primary Examiner.

Claims (1)

1. A SNAP ACTION ELECTRIC SWITCH COMPRISING, (A) A MOUNTING BASE, (B) CAGE MEANS PIVOTALLY SECURED TO SAID BASE AND MOVABLE BETWEEN A CLOSED POSITION AND AN OPENING POSITION, (C) CONTACT MEANS PIVOTALLY SECURED TO SAID CAGE MEANS AND ADAPTED TO ASSUME A RETRACTED OPEN POSITION AND A CIRCUIT MAKING TRIGGERED POSITION, (D) SPRING MEANS FOR URGING SAID CONTACT MEANS TOWARD SAID TRIGGER POSITION, (E) RESTRAINING MEANS FOR MAINTAINING SAID CONTACT MEANS IN SAID RETRACTED POSITION AGAINST THE FORCE OF SAID SPRING MEANS AS LONG AS SAID CAGE MEANS IS IN AN OPEN POSITION, (F) ARM MEANS ADAPTED TO IMPART A PIVOTING MOTION TO SAID CAGE MEANS, AND (G) RELEASING MEANS ACTUATED BY SAID ARM MEANS AND CONNENTED TO SAID RESTRAINING MEANS, SAID RELEASING MEANS BEING ADAPTED TO TRIP SAID RESTRAINING MEANS TO PERMIT SAID CONTACT MEANS TO SNAP INTO SAID TRIGGERED POSITION AS SAID CAGE MEANS PIVOTS TOWARD SAID CLOSED POSITION ACTUATED BY SAID ARM MEANS.

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