US2739199A - Electric switches and parts therefor - Google Patents

Description

March 20, 1956 2,739,199

R. O. PERRINE ELECTRIC SWITCHES AND PARTS THEREFOR Filed July 20, 1953 2,739,199 ELECTRIC SWITCHES AND PARTS THEREFOR "Robert 0. Perrine, Wauwatosa, Wis.,; assignor to Cutler- Hammer,--Inc., Milwaukee, Wis., acorporationof Delaware Application July 20, 1953, SerialNo.'369,086

3 Claims. (Cl. 200-67) acting mechanism for very rapid actuation of the switch contacts. In certain applications of such switches it is also required or desirable to incorporate in the switch'manually operable means to alter the operation or to render ineffective said snap-acting mechanism with respect -to a 'given normally automatic operation of the switch. Aprimary object of the invention is tov provide animproved snap-acting mechanism which, while not-limited thereto, is particularly suited for manual operation and which is inexpensive to manufacture and assembleand is readily adaptable for use in a variety of switches.

Anobject is to provide a switch having snap ac'ting mechanism for actuating the switch contactsin response to-a condition and further having manually operable snapacting mechanism to render the former snap-acting mechanism ineffective. Such manually operable mechanism provides a means to selectively set the device controlled by the switch or to fix the switch circuit in a givencondition and further provides that the manual commutation of the switch contacts will be accomplished withthe required rapidity.

tnal operation of the condition-responsive snap acting mechanism from being affected by the manual mechanism or by operation of the latter.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate an embodiment of=the invention whichwill now be described. lt is to be understood thatvarious modifications may be made in the structural-details thereof without departing from the spirit of the invention or the scope of the appended claims.

In the drawings, Figure 1 is a partly diagrammatic and partlymechanical fragmentary side view of a-switchjejm- 'bodyingthe invention;

Fig. 2 is a similar fragmentary front view of the switch shown in Fig. 1;

Fig. 3 is a top plan view of a preferred form of the manually opearble snap-acting mechanism employed; and

Fig. 4 is a side view of a preferred form of the bowed spring employed in the manually operable snap-acting mechanism illustrated in Fig. 3, shown in relaxed condition.

Referring to Fig. 1 of the drawing, the numeral gentes Patent '0 2 erally designates snap-acting, mechanism shown diagrammatically. Mechanism 10 may the 1 of the type disclosed and claimed in Robbins Patent No. {2;375387, granted vMay.18, l94 5, tothe, assignee of the presentjapplication. It comprises, as-jshown, a'snap-acting lever; 1 '2"pivotedj at jaj point 14, and a-second lever 16 pivoted atia' point .l for 'rotational'movement between spaced stops ZlljandiZLarid continually biased for. rotation toward stop 2'2"byfo,vercenter spring 24 held underitension between a point 26 'on' snap-acting lever 12 and a' point '28 on thefsecond" lever '16. The mechanism 10 further comprisesa'switch oper- .ating'member'39having a portion'30 engaging the upper surface of the second lever16. Memberfl30vis m'ovableflto rotatejsaid. lever16 towardistop '20 or'to, permitthelever 16 to .be rotated towardstop, 1 22 injja'ccordance with a condition. represented by a force. acting in -loppositi on to ;a main spring '32. The spring 32 is interposed between memberjtland a range adjustment mechanism '34.

The switch contact mechanism is'illustrated diagrammatically. A set of normally closed contacts comprising contacts 40, 40, and abridgingcontactor 3 2, are shown.

A push-bar 44, preferablycomposed of insulating material, is provided to. transmitthe snapmovement of snap- .aeting lever'lZ' tothe bridging contactorqllf Meanasuch as a spring 4 6 acting onffthebridging contacts, are .provi'ded to urgethe push b artf44f downwardlyunlcsssuch movement is prevented by, snap-acting ,lever11'2 or by, the manually operable snap-acting.rnechanismgenerally.desig- .nated ,48. Mechanism ".48 isfhereinaftermorefully de- :scribed. Thepush-bar 44is provided. withfa lateral extensionflltatits upper endand-a lateral extension 52. at, its lower end. Ajdiiferfintial adjustment screw Behaving-a fkerfed upperend 56,-a shank 158 which is threaded; atf58 land which terminates at its lower endtinta flanged portion 60 and ahead portion 62, extends through an opening in the, lower extensionfSZ of the ,push-bar 144. ,ITheportion 58 .of screw 54 is adapted fonadjustable engagement with a correspondingly internally threaded opening vin porti on 64.01?theswitch frame.

,Theover-centerspring124 ,urges thesccondleyer.16.14p- Tward against -the portion .litl fofv member .30. -'lThusgthe lever 16 is positioned in. accordance. with the relative .magnitu'des of the external iforce acting upwardly, -and the force of the main spring .32 acting vtlownvvartlly,,on mem ber ,3.0. When, assliown, lever 16 is positioned so; that the axisof over-center spring 24,.is below. the pivot 14 .of thesnap-acting lever 12, .th'e latter levenis.,b'iased downwardlyby over-centerv spring-24m that its r jd 12 engages the upper surface of fiange.. 6 0. ;Unless. .res t1ained,;as .shown,.,by snap acting mechanismt tii, the .push-barc44 is moved, downwardly, by spring means 46 into engagement with .lever. 12. ln that gposition -.of ;the push-bar, contacts 0,..40 are engaged .by-bridging contactor. 42.

If, member .30..is .movedupwardly permitting upward movement of lever 16 v.to carry,,the axis of over-center spring. 24 above, pivot-14, leverIlZ -,wi ll snap upwardly. End. ;12 of lever"1 2 will lift the;p u s h-.bar 44 x to elfect electrical disconnection of contacts .40, '40. Ihe operating differential of the switch is determined by the arcthro'ugh which point'26 onlever;=12'is1permitted to'move and may jthere fore be adjusted by raising-or lowering flange 60 by turning thediiferentialscre 54.

The push-bar 44 may be selectively released for movement by lever 12 and spring means 46, as aforedescribed, or may be lifted to its upper position as shown by snapacting mechanism 48 so that snap-acting mechanism 10 has no effect thereupon.

Referring to Figs. 2 and 3, mechanism 48 includes a generally U-shaped spring 70 of suitable resilient metal and an operating lever 72 which are pivotally interconnected. The spring 70 and lever 72 are pivotally cou- Patented Mar. 20, 1956 nected to walls 74 and 76, respectively, of an inner switch frame and are trapped between said walls 74 and 76 so that spring 70 is held under compression. The extreme end 78 of one arm of spring 70 is of reduced width to form a pair of shoulders 80, 80. End 78 extends laterally into and opening 82 formed in wall 74 so that shoulders 80, 80 bear against the wall 74 to form a pivot for pivotal movement of spring 70 with respect to said wall 74. The other arm of spring 70 is provided with an opening 84 (Fig. 3) adapted to accommodate the reduced end portion 86 of operating lever 72.

Lever 72 is preferably formed from a strip of suitable resilient metal. Its reduced end portion 86 is adapted to provide a pair of shoulders 88, 88 which bear against spring 70 adjacent to opening 84 in the latter to form a pivot for relative pivotal movement between spring 70 and lever 72. The other end portion 99 of lever 72 is of reduced width to form a pair of shoulders 92, 92 at a point intermediate the length of the lever. Portion 90 extends through an opening 94 formed in wall 76 and shoulders 92, 92 bear against said wall adjacent to opening 94 to form a pivot for pivotal movement of lever 72 about the wall 76. The extreme outer end or handle portion 96 of lever 72 may be further reduced in width, as shown, to extend through an opening 98 formed in an outer frame or cover 100 of the switch. End 78 of spring 70, and portion 90 and handle 96 of lever 72 are preferably provided with integral offset portions or beads 102 and 104, respectively, to lend strength and rigidity thereto.

Mechanism 48 is disposed between walls 74 and 76 in such manner that at least a portion of lever 72 lies between flange 60 of differential screw 54 and the lateral extension 52 of push-rod 44. When handle 96 of lever 72 is depressed, the pivotal connection between lever 72 and spring 70 lies a short distance above a line connecting the pivotal connection of spring 70 with wall 74 with the pivotal connection between lever 72 and wall 76. Thus spring 70, which is under compression, urges lever 72 upwardly to lift push-bar 44 to its upper extreme position, as illustrated, and motion of snap-acting lever 12 is ineffective to change the position of the push-bar 44 or to actuate the switch contacts.

When handle 96 is lifted (see Fig. 2), the pivotal connection between lever 72 and spring 70 is carried below the line connecting their respective pivot shoulders 92 and 80 and lever 72 is snapped downwardly until it abuts flange 60. Thus the push-bar 44 is released for downward movement by snap-acting lever 12 and means 46.

If, while snap-acting lever 12 is disposed in the downward position, shown mechanism 48 is operated by move ment of the handle 96 in either direction, the contacts 40, 40 will be opened or closed with a snap movement just as would be provided by mechanism 10. The operation afforded by mechanism 48 is provided without the necessity of modifying, connecting with, or otherwise complicating the primary control mechanism and without complicating the operating differential adjustment mechanism. Moreover, mechanism 48 may readily be reversed so that the handle 96 extends from the opposite side of the switch. If preferred a handle portion (corresponding with portion 96) might extend from the spring 70 instead of from the lever 72.

The sizes of lever 72 and of spring 70, the latter being illustrated in relaxed condition in Fig. 4, are chosen so that when assembled in trapped relation between walls 74 and 76 and with lever 72 disposed between the push-bar 44 and flange 60, the spring is continuously held under compression.

Mechanism 43 need comprise only two members in addition to the otherwise required frame walls 74 and 76 or their equivalent; no other fastening or auxiliary devices being required. Thus an easily assembled, inexpensive and dependable mechanism is provided. I

I claim:

1. For combination with a switch, a switch operator movable to a switch actuating position, automatic snapacting mechanism including a snap-acting lever engageable with said switch operator and responsive to a condition to move said switch operator to a switch actuating position, spaced frame members, a second snap-acting mechanism comprising an operating lever and a compression spring hingedly interconnected with said operating lever and trapped therewith between said spaced frame members, said operating lever and said spring each being hingedly connected to a respectively associated one of said spaced frame members and said operating lever being engageable with said switch operator, and directly manually operable handle to effect snap operation of said second snap-acting mechanism to urge said switch operator to said switch actuating position.

2. The combination defined in claim 1, including a member positioned for engagement by said snap-acting lever to limit movement of the latter when moved in a direction to release said switch operator from said switch actuating position to determine the operating difierential of said switch, said last mentioned member being'further positioned for engagement by said second snap-acting mechanism when snapped in a direction to release said switch operator from said switch actuating position to limit the motion thereof to less than that degree of movement required to release said spring from compression.

3. In combination, an electric switch including a switch operator member movable from a first toa second actuating position, means for biasing said member in said first position, snap-acting mechanism responsive to selected conditions to move said member to said second position and to release said member for movement by said bias means, spaced supports, and another snap-acting mechanism trapped between said supports and manually movable to engage said member and move the same to said second position and to release said member for movement by said bias means, said other snap-acting mechanism comprising a compression spring having an end thereof pivotally connected to one of said supports, and a lever having one end portion thereof pivotally connected to the other end of said compression spring and an intermediate portion pivotally connected to the other of said supports, said lever further having a second end portion for manually pivoting said lever for operation of said other snap-acting mechanism.

References Cited in the file of this patent UNITED STATES PATENTS

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