US2668449A - Snap-acting mechanism for opening electric switches and the like - Google Patents

Description

W. SNAP-ACTING Feb. 9, 1954 E. DUNSHEE 2,668,449

MECHANISM FOR OPENING ELECTRIC SWITCHES AND THE LIKE 4 Sheets-Sheet 1 Filed Feb. 18, 1950 A INVENTOR. Wdlaam [Dims/Zea,

Feb. 9, 1954 w. E. DUNSHEE 2,668,449

SNAP-ACTING MECHANISM FOR OPENING ELECTRIC SWITCHES AND THE LIKE 4 Sheets-Sheet 2 Filed Feb. 18, 1950 INVENTOR ill/ 471 i Feb. 9, 1954 w. E. DUNSHEE 2,668,449

SNAP-ACTING MECHANISM FOR OPENING ELECTRIC SWITCHES AND THE LIKE Filed Feb. 18, 1950 4 Sheets-Sheet 3 INVENTOR.

Feb. 9, 1954 w. E. DUNSHEE SNAP-ACTING MECHANISM FOR OPENING ELECTRIC SWITCHES AND THE LIKE 4 Sheets-Sheet '4 Filed Feb. 18, 1950 INVENTOR. Wllzczm [Dana/we, BY

Patented Feb. 9, 1954 SNAP-ACTING MECHANISM. FOR OPENING ELECTRIC SWITCHES AND THE LIKE William E. Dunshec, Glenview, BL, ass-ignor' to- S 8; Electric Company, Chicago, Il1=,,- a corporation of Delaware Application February 18, 1950, Serial No. 144,955

(CI. M -97) 1 3-1Claims. 1

This invention relates, generally; to motion translating devices, and it has particular relation to bell crank type snap acting mechanisms for opening high voltage electric circuit interrupter switches and the like. It constitutes an improvement with respect to outdoor type remoteiy operated switches over the invention disclosed in copending application Serial No. 144,297, filed February 1950-, and assigned to the assignee of this application, now Patent No. 2,638,003, issued May 12, 1953.

Among the objects of this invention are: To provide for operating a driven member or arm constituting a part of a bell crankand connected to an electric switch or the like to open the same with a snapaction after movement of' a driving member or arm constituting another part of the bell crank through a predetermined extent; to employ a spring wound or tensioned by the driving member or arm to accomplish this snap action; topretension the spring; to mount the driven member or arm so that its free movement is not impeded by bearing pressure between the driving member or arm and the bearing support therefor; to telescope the driven member or arm over the driving member or arm with the former being freely rotatable over the latter about its axis of rotation; to hold the driven member or am against movement while the spring is being woundv or tensioned by the driving member or arm; and to release the driven member or arm for movement by the spring when the driving member or arm. has been moved through a predetermined extent to tension the same.

Other objects of this invention will, in part, be obvious and in part appear hereinafter;

This invention is disclosed. in the embodiment thereof shown in the accompanying: drawings and it comprises the features of construction. combination of elements and arrangement ofpartswhich will be exemplified inthe constructionv hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of this invention, refercncemay be had to the following detailed description,

taken together with the accompanying drawings, in which:

Figure 1. is a top plan view of a switch frame structure, showing a part of the same and how interrupter switches may be mounted on top thereof;

Figure 2 is a view, in side elevation, of the 2 switch frame structure, the switches being omitted and the operating linkage being shown;

Figure" 3' is a top plan view" of a snap acting mechanism, incorporated in the switch frame structure shown in the preceding figures, in which the present invention is embodied;

Figure 4 is a detail sectional view taken generally along the line 4-4 of Figure 3-;

Figure 5 is a top plan view of a portion of the snap acting mechanim and showing only the base therefor together with the driving member or arm in conjunction with a portion of the latch mechanism;

, Figure 6- is a top plan view of a portion of the snap acting mechanism, showing the driven and driving members or arms the positions which they occupy when the switch is closed, the main spring and spring anchor being omitted;

Figure 7 is a view, similar to Figure 6' but showing the relative positions of the driven and driving members or arms when the latch mechanism has been released by the movement of the driving arm through a predetermined extent and just after movement of the driven arm has started; and V Figure 8 is a view, similar to Figures 6 and 7 but showing the relative positions of the driven and driving members or arms in the switch open position.

Referring now particularly to Figures 1 and 2 of the drawings, it will be observed that the reference character W designates, generally, a switch frame structure which may be built up of galvanized iron pipe or other suitable frame members as will be understood readily. switch frame structure I0 is arranged to carry at its upper end interrupter switches one of which is indicated, generally, at H in Figure 1. Since the interrupter switches Ii I? are identical in construction, only one is shown. The interrupter switch It may be: provided with. stationary contact assemblies I22 which are carried at the upper ends of stationary insulators iii. A switch blade It serves to interconnect the stationary contact assemblies 12in the switch closed position. The switch blade M is mounted for rortation with a rotatable insulator 15 that is disposed midway between the: stationary insulators.

i 3. It will be noted that the insulators l3. and t5 are mounted on a channel base 16, there being a channel base It for each interrupter switch H, as shown.

The channel bases [6 may be mounted on cross frame members I! which form :a part of the switch frame structure I -Band an operating arm l8 extends from the base of the rotatable insulator l5 of each interrupter switch H for rotating the switch blade l4 individual thereto from and to the switch closed position.

With a View to effecting simultaneous operation of each of the interrupter switches H, the operating arms I8 are interconnected by interphase connectors i9. In the particular constructions shown the left hand operating arm I2 is connected by a connector 28 to a driven memher or arm 2| which forms a part of a snap acting mechanism, shown generally at 22, in which the present invention is embodied. The snap acting mechanism 22 functions as a bell crank for connection to the connector 20. It includes a base 23 which may be secured in a suitable manner to a mounting plate 24 that is carried by the switch frame structure ID.

The snap acting mechanism 22 also includes a driving member or arm 26 the outer end of which is operatively connected to a connector pipe 21 which may be operated by a like connector pipe 28, the pipes 2'! and 28 being interconnected by a pivoted guide mechanism shown, generally, at 29. A manually operable handle 30 is rockably mounted on the switch frame structure It] and is suitably connected to the lower end of the connector pipe 28. The handle 30 is arranged to be swung in the are indicated by the broken line 3| for operating each of the interrupter switches H from the closed position shown in Figure l to an alternate open position where the switch blade I4 is at right angles to its closed position. If desired, provision can be made for operation by a motor mechanism, such as an electric, spring or fluid motor instead of by man ually moving the handle 30. It will be understood that each switch blade IA is swung in a clockwise direction to the switch open position and in a counterclockwise direction to the switch closed position.

The particular mounting of the snap acting mechanism 22 on the switch frame structure l0 shown in Figures 1 and 2 is for illustrative purposes only. It will be understood that the snap acting mechanism 22 can be mounted and operated in a setting other than the one shown specifically in the drawings and described hereinbefore as may be desired. For example, as indicated, a motor mechanism, arranged for remote control, can be used to transmit torque therethrough to operate the interrupter switches i Reference now may be had to Figures 3 and 4 of the drawings. As there shown, each of the memhere or arms 2| and 26 is provided with an aperture and 36, respectively, near its outer end for receiving a connecting pin 31 and 38. It will be understood that the pin 31 is employed for making connection to the connector 25 while the pin 38 interconnects the driving member or arm 25 and the connector pipe 21.

As shown in Figure 4 a stationary shaft 39 extends forwardly from the base 23. Rotatably mounted on the shaft 39 is a sleeve all which is formed integrally with the driving member or arm 26. At the ends of the sleeve it bearings 4| are provided so that the sleeve 40 is journalled at its ends on the stationary shaft 39. Since the bearings 4| are fairly widely spaced apart, they provide in effect a relatively long bearing surface for taking care of the stress applied through the driving member or arm 26 when the manually operable handle 30 is swung from one position to the other.

Any suitable means can be employed for holdl ing the sleeve 4|! and the driving member or arm 26 in position on the stationary shaft 39. As shown, a nut '32 is threaded on a stud 43 which projects forwardly from the outer end of the stationary shaft 39. The nut 42 bears against a washer 44. If the fit requires, one or more shim washers 45 may be employed underneath the washer 44 to reduce end play of the sleeve 40 on the stationary shaft 39.

It is desirable that the driven member or arm 2| be mounted so that it can rotate freely and without being impeded in any way by bearing pressure between the driving member or arm 26 and the shaft 39 on which it is rockably mounted. Such action is desired since, as will appear hereinafter, the driven member or arm 2| and the parts associated therewith are rotated to the switch open position by means of a spring which is wound or tensioned by the initial movement of the driving member or arm 26 while the driven member or arm 2| is held stationary. In order to accomplish these ends a sleeve 4? is formed integrally with the driven member or arm 2| and it is telescoped over the sleeve 40 which, it will be recalled, is journalled by means of bearings 4| on the stationary shaft 39. Bearings 48 are located at the ends of the sleeve 41 and they are freely rotatable on the outer surface of the sleeve 40. In this manner the driven member or arm 2! is freely rotatable on the sleeve 40 and, therefore, is unaifected by any bearing pressure which may be developed between the bearings 4| and the stationary shaft 39 in the operation of the driving member or arm 26.

As indicated hereinbefore the driven member or arm 2| and parts associated therewith are operated by a pretensioned spring which is further wound or tensioned by an initial movement of the driving member or arm 26 while the driven member or arm 2| is held stationary. For this purpose a coil spring or main spring 49 is employed. It will be noted in Figure 4 that the convolutions of the spring 49 extend around the sleeve 41 and are spaced therefrom. One end 50 of the spring 49 extends into an aperture 5| in the hub interconnecting the sleeve 41 and the driven member or arm 2|. As shown in Figure 6 there are two sets of apertures 5| each set comprising two apertures. One set of apertures is employed for right hand mounting and the other is employed for left hand mounting. One or the other aperture of each set is used depending upon the initial tensile properties of the spring 49 that is employed. The other end 52 of the spring 49 extends into an aperture 53 of a spring anchor 54 that is fast on the outer end of the sleeve 40. The spring anchor 54 may be held in position by a set screw 55 which projects into an aperture 56, Figure 4, near the outer end of the sleeve Gil. The spring 49 is pretensioned by applying a suitable wrench to the spring anchor 5s and rotating it until the set screw 55 registers with the aperture 56. Thereupon the set screw 55 is tightened as shown in Figure 4.

As has been indicated hereinbefore, the driven member or arm 2| is held stationary while the driving member or arm 26 is rocked to a predetermined position. During this limited movement of the driving member or arm 25 the spring 49 is further tensioned. In order to accomplish this holding action and subsequent releasing action a latch mechanism, shown generally at 58 in Figures 4, 5, and 6 is employed. The latch mechanism 58 includes a latch arm 59 which is rockably mounted on a stud 69 that projects forwardly from thebasefl; Thelatch: arm 58- biased into operative engagement with the driven and :drhring members or arms 2i and 2'6 bya coil latch spring H which surrounds the lower portion or the. stud W and reacts between the latch arm 59 and the stud 60. At its outer end the latch arm 55 carriesa transversely extend-mg shaft 62 on the ends of which rollers 63 and 6d are mounted. As will appear hereinafter, the roller 61 constitutes a cam follower the function of which will be. set forth presently;

The latching function is performed by the roller 63 in engagement with a detent 65', Figure 6, which extends radially outwardly from the hub of the driven member or arm 2|. The latch arm 59- androller 63 in their positions shown in Figure 6- serve to hold the driven member or arm 21 stationary while the drivingmember or arm 28 is rocked toward the switch open position. When the main spring 4'9 has been further stressed to the extent corresponding to the movement of the driving member or arm 26 through the limited extent just referred to, the latch arm 59 is rocked slightly so as to move the roller 63 tosuch a position with respect to the detent 65 that the latter is no longer restrained. For this purpose the driving memberor arm 26' has a cam 56, Figure 5', formed integrally therewith. The cam 66- has a cam surface 61 on which the roller 64 rides and acts as a cam follower; It will beunderstood that the latch spring El acts tohold the roller 64 or cam follower in engagement with the cam surface 61. As the driving member or arm 26- is' rocked in a clockwise direction, as viewed in Figure 5*, the roller or cam follower 615 rides over the camsurface 6? andthe latch arm 59 is rocked in the direction indicatedby the arrow 63. At the end of the cam surface 61 the roller or cam fol-lower 64 runs onto a circular surface 6% and no further outward rocking movement of the latch arm: 5-9 in the direction of the arrow 68 is caused. By this time the roller 63 has moved to-such a position with respect to the detent 65 that the driven member or arm 2| no longer is held and thespring- 49- then releases a portion of the energy stored therein and operates the driven member or arm 21 with a snap action toward the drivingmemberor arm 26.

As shown in Figure 5 the driving member or arm 26 has a boss 10- with ashoulder H at one end that is arranged to engage a shoulder 12. Figure- 6, on the underside of the hub of the driven member or arm 21 inthe event that, for some reason such as corrosion of the contact surfaces of the switches l l-, their being encased in ice, etc;, the spring 49 should not be powerful enough by itself to operate the mechanical linkage and open the switches H. This engagement takes place-at the time that the roller 63ism-oved sufiiciently out of the path of the detent 65- as to permit the movement of the driven member'or arm 21 underthei'nfluenceof the spring 49 and in addition by the direct application of' operating torque fromthe driving member or arm- 26' to the driven member or arm 21 The boss-1'0 has a shoulder'lS at the opposite endwhich is arranged to engage a shoulder 14 on the underside of the hub of the driven memher or arm 21. When the driving member orarm 26 is rocked in a counterclockwise direction for closing the switch, the shoulders 13 and F4 ongage and the; driven and driving members or arms; 21: and: 26. are: rocked unitaril y without any relative movement. therebetween for efi ecting the swifi hi closing. operation It wild be: apparent 6 that. the boss 10 cooperates: with shoulders t2 and IS-toefieot direct: interconnection between the. driven and. driving members or arms 2! and 26 under the. conditions described- It is desirable. to protect the main spring 49 and, parts associated therewith from the; weather. For this: purpose: a cup like cover 15 may be employed. As. shown in Figure 4 the. inner end of thecover 1J5 interfits with a flange l6: and may be held; inposition thereon by suitable screws one of which is shown at H.

The snap: acting mechanism 22 shown in the drawings and described hereinbefore is. intended for right hand mounting. That is, the driving member or arm to is shown at the right and the driven member or arm 2t is: positioned at the Ieft. If desired, their positionscan be reversed. The various parts shown in the drawings, exceptior the springs 49 and 61 are arrangedand constructed for either right hand or left hand mounting. Where the opposite hand mounting is. desired, the springs 49 and 61 are changed so as to: accommodate the alternate construction. Otherwise no changes are required for the alternate positioning of the driven and driving members or arms 2| and Z6 and the positioning of the latch arm 59 to operate from the left rather than from the right as shown in Figure 6; for example, of the drawings.

In: operation, when the interrupter switches H are. closed, the driven and driving members or arms 2| and: 26 occupy the relative positions shown in. Figures 3 and 6. of the drawings; Here the angle betweenthem is about 99. Now it will. be assumed that: the handle 30i is op.- erated manually or otherwise from its: position shown. Eigure 2: to the alternate lowermost position. Initially the. driving. member or arm 25 is rocked: in. a. clockwise direction. During this movement. the. driven member or arm 21 is. heldi stationary by the latch mechanism 58 in. the manner described- When the driving member or arm- 26' has been rocked. through an angle of about. 3.0- to, the; position. shown inFigure '7, the latch. am: 59: has been rocked; in a clock;- wise direction. through. an extent sufficient to move out of the path of the detent. 6.5. There.- upon the spring 49, which. hasv been further stressed during the initial movement or the driving member or arm 26,,operates. the: driven mermher or arm; 2-1; with a. snap action. in a clockwise direction.

In the event: that the. friction drag; should be so. great that. the spring 49; cannot move the switch blades l4. away from the: switch: contacts 12:, the shoulder; H on the; boss 10 engages: the shoulder 12 and the driven and. driving members or arms. 21 and 26 act. momentarily" as: a rigidibeli crank to break. the switch blades: loose andovercome; the friction drag- Once the switch blades l4. start to move, the spring: 49', acting through the driven member" or: arm. 21:, swings the switch blades M- with: a. snap action to enact a oorrespondingoperation of the loadinterrupter devices associated with. each: switch. blade. I4 and corresponding rapid interruption; of the current. flow thereby before contacts. on the switch blades move out. of engagement with the load interrupter devices. This'snapaction bythe' spring 49- takes place: and the circuit is quickly opened even. though the operator or motor mechanism may move the handle 30- or other like: operating member: at a: very slow: speed.

After the. spring 4'9! has performed: its functioni and; operated the: driven member or arm 21' until its shoulder 14 engages the shoulder 13, further opening movement of the switch blades I4 is caused by a conjoint movement of the driven and driving members or arms 2! and 26 acting as a rigid bell crank until the handle 30. occupies the lowermost position, the members or arms 2! and 26 are disposed as shown in Figure 8, and the switch blade 14 of each interrupter switch II is positioned at right angles to the position which it occupies in the switch closed position.

When the interrupter switches H are to be closed, the handle 30 is swung upwardly. Since the shoulders 13 and 74 are in engagement when the interrupter switches I I are opened, as shown in Figure 8, the driven member or arm 2| is moved conjointly with the driving member or arm 26 in a counterclockwise direction to effect the closing movement of the interrupter switches.

Since certain changes can be made in the foregoing construction and different embodiments of the invention can be made without departing from the spirit and scope thereof, it is intended that all matter shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

l. A snap acting device comprising, in combination, a rockably mounted driving member, a driven member telescoped over said driving member and freely rockable thereon about its axis of rotation in substantially the same plane in which said driving member rocks, a coil spring telescoped over said driven member and interconnecting said members, a detent on said driven member, a latch member cooperating with said detent and acting to prevent movement of said driven member, a cam on said driving member, and a cam follower on said latch member engaging said cam, said driving member being rockable through a predetermined arc to tension said spring around said driven member while said driven member is restrained by said latch member engaging said detent until said cam operates said latch member out of engagement with said detent whereupon said driven member is rocked with a snap action by said spring toward said driving member.

2. A snap acting device comprising, in combination, a rockably mounted driving member, a driven member telescoped over said driving member and freely rockable thereon about its axis of rotation in substantially the same plane in which said driving member rocks, a coil spring telescoped over said driven member and interconnecting said members, a detent on said driven 1 member, a latch member cooperating with said detent and acting to prevent movement of said driven member, a cam on said driving member, and a cam follower on said latch member engaging said cam, said driving member being rockable through a predetermined arc to tension said spring around said driven member while said driven member is restrained by said latch member engaging said detent until said cam operates said latch member out of engagement with said detent whereupon said driven member is rocked with a snap action by said spring toward said driving member, said driving and driven members being symmetrically arranged and constructed for either right or left hand assembly.

3. A snap acting device comprising, in combination, a rockably mounted driving member, a driven member telescoped over said driving member and freely rockable thereon about its axis of rotation, a spring interconnecting said memhere, a detent on said driven member, a latch member cooperating with said detent and acting to prevent movement of said driven member, a cam on said driving member, a cam follower on said latch member engaging said cam, said driving member being rockable through a predetermined arc to tension said spring while said driven member is restrained by said latch member engaging said detent until said cam operates said latch member out of engagement with said detent whereupon said driven member is rocked with a snap action by said spring toward said driving member; arcuately spaced shoulders on one of said members, and a cooperating boss on the other of said members whereby direct driving engagement therebetween is had when said driving member has rocked through said are and said latch member is moved out of engagement with said detent and direct driving engagement therebetween also is had when said driving member is rocked in the opposite direction.

4. A snap acting device comprising, in combination, a stationary shaft, a driving member journalled on said shaft, a driven member telescoped over said driving member and rockable thereon about its axis of rotation free of bearing pressure between said shaft and said driving member in substantially the same plane in which said driving member rocks, a coil spring telescoped over said driven member and interconnecting said members to provide a driving connection therebetween, and latch means cooperating with said members for restraining said driven member while said driving member is rocked to wind said spring around said driven member until said driving member reaches a predetermined position whereupon said latch means is released and said driven member rocks with a snap action toward said driving member under the biasing action of said spring.

5. A snap acting device comprising, in combination, a shaft, a driving member journalled on said shaft, a driven member telescoped over said driving member and rockable thereon about its axis of rotation free of bearing pressure between said shaft and said driving member, a spring interconnecting said members to provide a driving connection therebetween, latch means cooperating with said members for restraining said driven member while said driving member is rocked to wind said spring until said driving member reaches a predetermined position whereupon said latch means is released and said driven member rocks with a snap action toward said driving member under the biasing action of said spring; arcuately spaced shoulders on one of said members, and a cooperating boss on the other of said members whereby direct driving engagement therebetween is had when said driving member has rocked through said are and said latch member is moved out of engagement with said detent and direct driving engagement therebetween also is had when said driving member is rocked in the opposite direction. I

6. A quick break mechanism for interconnection between a switch and an operating member to operate the former with a snap action when the latter is operated to a predetermined position from a position corresponding to the closed position of the former comprising, in combination, a rockably mounted driving arm adapted to be connected to said operating member, a rockably mounted driven arm adapted to be connected to said switch, a main spring interconnectingsaid'driving and driven arms, a detent onsaid driven arm, a rockably mounted latch arm'sfor engaging said detent, a latch spring biasing said latch arm into the path of said detent to prevent movement of said driven arm, a cam movable with said driving arm, and a cam follower carried by said latch arm for engaging said cam and biased into engagement therewith by said iatch' spring, said driving arm being rockable through a predetermined arc to tension said main spring while said driven arm is restrained by said latch arm engaging said detent until said cam acting through said cam follower moves said latch arm out of the path of said detent whereupon said driven arm is rocked with a snap action by said main spring toward said driving arm; arcua-tely spaced shoulders on one of said first mentioned arms, and a cooperating boss on the other of said first mentioned arms whereby direct driving engagement therebetween is had when said driving arm has rocked through said are and said latch member is moved out of engagement with said detent and direct driving engagement therebetween also is had when said driving arm is rocked in the opposite dimotion.

7. A quick break mechanism for interconnection between a switch and an operating member to operate the former with a snap action when the latter is operated to a predetermined position from a position corresponding to the closed position of the former comprising, in combination, a base, a stationary shaft carried by said base, a driving arm rockably mounted on said shaft and. adapted to be connected to said operating member, a driven arm rockably mounted solely on said driving arm about its axis of rotation and adapted to be connected to said switch, a main coil spring coaxial with and interconnecting sai'd' driving and driven arms, a detent on said arm, a latch arm rock-ably mounted on said base for engaging said detent to prevent movement of said driven arm, a cam integral with said driving arm, and a cam follower carried by said latch arm for engaging said cam and biased into-engagement therewith by said latch spring, said driving arm being rockable through a predetermined arc to tension said 'mainspring while said driven arm is restrain-ed by said latch arm engaging said detent until said cam acting through said cam follower moves said latch arm out of the path of said detent whereupon said driven arm is rocked with a snap action by said main spring toward said driving arm.

8. A quick break mechanism for interconnection between a switch and an operating member to operate the former with a snap action when the latter is operated to a predetermined position from a position corresponding to the closed position of the former comprising, in combination, a base, a, stationary shaft carried by said base, a driving arm adapted to be connected to said operating member, a sleeve constituting an integral extension of said driving arm journalled on said shaft, a driven arm adapted to be connected to said switch, a sleeve constituting an integral extension of said driven arm journalled on said driving arm sleeve, a coil spring telescoped over said driven arm sleeve and interconnecting said driving and driven arms, and latch means cooperating with said arms for restraining said driven arm while said driving arm is rockpd-through a predetermined arc to tension said spring around said driven arm sleeve 101 whereupon said latch means is released and said driven arm rocks with asnap action toward said driving arm under the biasing action of said spring.

9. A quick break mechanism for interconnection between a switch and an operating member to operate the former with a snap action when the latter is operated to a predetermined position. from a position corresponding to the closed posi-' tion of the former comprising, in combination, a base, a stationary shaft-carried by said base,

a driving arm adapted to be connected to said operating member, a sleeve constituting an integral extension of said driving arm journalled" on said shaft, a driven arm adapted to be connected to said switch, a sleeve constituting an integral extension of said driven arm journal led on said driving arm sleeve, a coil spring telescoped over said driven arm sleeve and interconnecting said driving and driven arms, and latch means:- cooperating with said arms for restraining said driven arm while said driving arm is rocked" through a predeterm'med are to tension said spring around said driven arm sleeve whereupon said latch means is released and said driven arm rocks with a snap action toward said driving arm under the biasing action of said spring, said driving and driven arms being symmetrically arranged and constructed for either right or left hand assembly.

10. A quick break mechanism :for interconnection between a switch and an operating member to operate the former with a snap action when the latter is operated to a predetermined position 1 from a position corresponding to the closed position of the former comprising, in combination, i a base, a shaft carried by said base, a driving arm adapted to be connected to said operating member, a sleeve constituting an integral extension of said driving arm journailed on said shaft, a driven arm adapted to be connected to said switch, a sleeve constituting an integral extension of said driven arm journalled on said driving latch means is released andsaid driven arm rocks with :a snap action toward said driving arm under the biasing action of said spring; and

arcuately paced shoulders on one of said arms and acooperating boss on the other of said arms whereby direct driving engagement is had when said driving arm has rocked through said are and said latch means is released and direct driving engagement therebetween also is had when said driving arm is rocked in the opposite direction.

11. A quick break mechanism for interconnection between a switch and an operating member to operate the former with a snap action when the latter is operated to a predetermined position from a position corresponding to the closed position of the former comprising, in combination, a base, a shaft carried by said base, a driving arm adapted to be connected to said operating member, a sleeve constituting an integral extension of said driving arm journalled on said shaft, a driven arm adapted to be connected to said switch, a sleeve constituting an integral extension of said driven arm journalled on said driving arm sleeve, a spring anchor fast to said first mentioned sleeve, a coil spring connected at one end to said spring anchor and surrounding said driven arm sleeve and connected at its other end to said driven arm, a detent on said driven arm,

a latch arm rockably mounted on said base for engaging said detent, a latch spring biasing said latch arm, into the path of said detent to prevent movement of said driven arm, a cam integral with said driving arm, and a cam follower 'carried by said latch arm for engaging said cam and biased into engagement therewith by said latch spring, said driving arm being rockable through a, predetermined arc to tension said coil spring while said driven arm is restrained by said latch arm engaging said detent until said cam acting through said cam follower moves said latch arm out of the path of said detent whereupon said driven arm is rocked with a snap action by said coil spring toward said driving arm.

12. A quick break mechanism for interconnection between a switch and an operating member to operate the former with a snap action when the latter is operated to a predetermined position from a position corresponding to the closed position of the former comprising, in combination, a base, a shaft carried by said base, a driving arm adapted to be connected to said operating memher, a sleeve constituting an integral extension of said driving arm journalled at its ends on said shaft, a driven arm adapted to be connected to said switch, a sleeve constituting an integral extension of said driven arm journalled at its ends on said driving arm sleeve, a spring anchor'fast to said first mentioned sleeve, a coil spring connected at one end to said spring anchor and surrounding said driven arm sleeve and connected at its other end to said driven arm, a detent on said driven arm, a latch arm rockably mounted on said base, a detent roller carried by said latch arm for engaging said detent, a latch spring biasing said latch arm and thereby said roller into the path of said detent to prevent movement of said driven arm, a cam integral with said driving arm, and a cam follower roller carried by said latch arm on the same axis as said detent roller for engaging said cam and biased into engagement therewith by said latch spring, said driving arm being rockable through a predetermined arc to tension said coil spring while said driven arm is restrained by said detent roller engaging said detent until said cam acting through said cam follower roller moves said detent roller out of the path of said detent whereupon said driven arm is rocked with a snap action by said coil spring toward said driving arm.

13. A quick break mechanism for interconnection between a switch and an operating member to operate the former with a snap action when the latter is operated to a predetermined position from a position corresponding to the closed position of the former comprising, in combination,"

a base, a shaft carried by said base, a driving arm adapted to be connected to said operating member, a sleeve constituting an integral extension of said driving arm journalled at its ends on said shaft, a driven arm adapted to be connected to said switch, a sleeve constituting an integral extension of said driven arm journalled at its ends on said driving arm sleeve, a spring anchor fast to said first mentioned sleeve, a coil sprin connected at one end to said spring anchor and surrounding said driven arm sleeve and connected at its other end to said driven arm, a detent on said driven arm, a latch arm rockably mounted on said base, a detent roller carried by said latch arm for engaging said detent, a latch spring biasing said latch arm and thereby said roller into the path of said detent to prevent movement of said driven arm, a cam integral with said driving arm, a cam follower roller carried by said latch arm on the same axis as said detent roller for engaging said cam and biased into engagement therewith by said latch spring, said driving 1 arm being rockable in a forward direction through a predetermined arc to tension said coil spring while said driven arm is restrained by said detent roller engaging said detent until said cam acting through said cam follower roller moves said detent roller out of the path of said detent whereupon said driven arm is rocked forwardly with a snap action by said coil spring toward said drivin arm, and interengaging shoulders on said driving and driven arms for rocking the latter unitarily with the former on reverse movement thereof.

WILLIAM E. DUNSHEE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 635,373 Downs et al. Oct. 24, 1899 665,514 Ely Jan. 8, 1901 1,760,547 Fisher May 27, 1930 1,895,650 Carmean Jan. 31, 1933 1,945,819 Millermaster Feb. 6, 1934 1,979,277 McLoughlin et al. Nov. 6, 1934 2,462,779 Russell Feb. 22, 1949 2,468,463 Rowe Apr. 26, 1949

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