US2556216A - Snap switch mechanism - Google Patents

Description

June 12, 1951 E. c. RANEY 2,556,216

SNAP SWITCH MECHANISM Filed Jan. 17, 1948 .l I 2 \F INVENTOR. M 58 7'54 0. BAA/6') Patented June 12, 1951 SNAP swrrcn MECHANISM Estel C. Raney, Delaware, Ohio, assignor to Ranco, Incorporated,,Columbus, Ohio, at corporation of Ohio Application January 17, 1948, Serial No. 2,822

2 Claims. (Cl. 200-67) The present invention relates to a snap switch mechanism and more particularly to a double throw snap switch in which the movable contact is moved with a snap action in opposite directions.

An object of the invention is to provide a double throw snap acting switch which will maintain a positive contact pressure until the instant that the contact is moved with a snap action from either contact to the opposite contact.

Another object of the invention is to provide a snap acting switch which requires a minimum of pressure to actuate the mechanism and at the same time provides positive contact pressure as the switch actuating member is gradually moved from one switch actuating position to the other.

Other objects and advantages of the invention will be apparent from the following description of a preferred form of the invention, reference being made to the accompanying drawings wherein:

Fig. lis a side view in elevation of a double throw snap acting switch, parts thereof being broken away for the sake of clarity;

Fig. 2 is a plan view of the switch shown in Fi 1;

Fig. 3 is a diagrammatic illustration of the switch parts when the switch is in one position;

Fig. 4 is a View similar to Fig. 3 but showin certain parts of the switch in another position;

Fig. 5 is a view similar to Fig. 3, but showing the switch members in the opposite position; and

Fig, 6 is a view similar to Fig. 4 but showing the switch members in the opposite position.

The present switching mechanism may be operated by any suitable actuating means such as by a thermostat or manually operated means, but for the purposes of illustrating the invention I have shown a manually operated switching mechanism indicated generally at 10. The mechanism I comprises a base member II which is preferably formed of a suitable dielectric material. A rigid bracket I2 is riveted to the base II and this bracket includes a platform portion I3 which is spaced from and extends parallel to the upper surface of base H. The ends of a U shaped strip M are attached to the platform l3 by screws l and the yoked end of the strip has attached thereto a pair of contact members Hi. The strip I4 is preferably formed of a flexible, resilient material which is also a good electric conductor, such as beryllium copper, for example.

Two fixed contact posts 11, only one of which appears in thedrawings, is riveted to the base H and carry contact surfaces l8 which are engaged by the contacts I6,'respectively. Suitable means, not shown, may be provided for connecting lead wires to the contact post l1. Two brackets 20 and 2! are attached at one end to opposite sides of the base H and the opposite ends of these brackets extend above the base II and each carry a contact 22 which are disposed in alignment with the upper surfaces of the respective contacts R6. The brackets 20 and 2| are riveted to the base and they are also provided with threaded openings 24 for receiving terminal screws, not shown. The positions of the contacts 22 relative to the base ll may be adjusted by screws 25 which are threaded into openings in the brackets 20 and 2| so that by turning the respective screws 25 the brackets will be moved toward or away from the base II respectively. It will be seen that the free end of the strip l4 may be shifted between the two sets of fixed contacts l8 and 22 for making and breaking two circuits through the switch.

The strip M is adapted to be shifted from one set of contacts to the other with a snap action by a toggle mechanism which comprises a toggle member 26 and a compression spring 3i. One end of the toggle member 26 is pivoted on one end of a fixed plate 21 by a V bearing structure. The opposite end of the plate 21 is anchored to the platform l3 of bracket l2 and the plate 21 is reinforced by strips 28 disposed on opposite sides thereof. The plate 21 and strips 28 are preferably of resilient material normally flexed upwardly and the position of the pivot end of plate 21 is fixed by the head of a screw 30, which screw extends through an opening through the plate and strips and which is threaded into the base II. The head of the screw 30 engages the upper plate 28 and thereby positions the end of plate 21 to which the toggle member 26 is pivoted. By adjusting the screw 36 the position of the pivot point for the toggle member 26 can be accurately fixed, and this point is adjusted to lie midway between the center line positions of strip 14 when the strip is in the positions to engage contacts [6 with contacts 18 and 22, respectively, as seen in Figs. 4 and 5.

As may be seen clearly in Fig. 2, the toggle member 26 is disposed to be in alignment with the opening between the legs of the strip 14,

and the C-shaped compression spring 3| is interposed between the free end of the toggle member 26 and the yoke of the strip l4. 'As is shown in the drawings, the connections at the ends of the opening are V and knife edged to minimize friction. It will be seen by comparing Figs. 3, 4 and 5 that the toggle member 26 and spring 3| form a toggle joint movable from one side to the other of a dead center position, which position is indicated by the line 32 in Fig. 4. When the toggle member 26 is in the lowered position as seen in Fig. 3, the spring 3| will urge the member [4 upwardly so that contacts I6 will engage contacts 22. When the of the strip The instant that member 26 passes snap movement, as is illustratedin Fig.5. The

same type of snap movement will occur in the opposite direction with the toggle member passing through its dead center while the spring applies a downward force on strip M, :as may be seen inFig. 6.

In order to obtain the rapidsnap movement M by the toggle comprising the member 26 and spring 3! it is essential that the toggle member be free to move after it has passed its dead center position. To provide for this free movement the switch is adapted to be actuated by 'a member which is connected to the toggle member 26 by a lost motion connection. The actuating member 35 consists of a U-shaped spring member'having the ends of its legs anchored to the platform 13 of bracket 12. The outer end of the bracket has a downturned tongue 38 provided with a slot 3'? there- 'in through which the member 25 extends. The slot 3"! is somewhat longer than the depth of the toggle member 26 so that as the toggle member is moved through dead center 'it will be free to travel from one end of the slot to the other, thereby permitting a snap movement of the free end of the toggle member to the opposite side of the center line of strip [4 and thereby impart a snap movement to the strip Id. In the present embodiment the actuating member 35 is normally biased upwardly to normally maintain the switch mechanism in the position shown in Fig. 5. The'actuating member may be depressed by any suitable type of actuating device, and in Fig. 1 there is indicated a'cover '38 having a push button 39 reciprocable therein and engageable with the actuating member 35.

The snap switch just described isparticularly suitable for double throw switches because it provides positive contactpressure up to the instant of snap movement of the movable 'contact carrier in opposite directions. It will be understood that the mechanism is suitable 'for single throw switches, in which case either .one of the contacts It .or.22 could be eliminated and suitable stop members substituted therefor.

The snap mechanism enables relatively light weight parts to be utilized, thereby reducing the power necessary to actuate the switching mechanism so that the mechanism could be operated by sensitive thermal responsive elements to provide close response to temperature conditions.

Although Ihavedescribed but one form of the invention it is to -be-understood that otheriorms might be adopted, all falling within the scope of the claims .which follow.

I claim:

1. A double throw snap acting switch mechanism comprising an elongated strip anchored atone end and having a contact at the .opposite end, a pair .of spaced .stops between which said opposite end of said strip is adapted to shift, a toggle member extending in the same 4 general direction as said strip, means pivotally supporting one end of said toggle member intermediate the ends of said strip, the other end of said toggle member being swingable from one .side to the other of the center line of said strip,

said strip being adapted to move from one side to "the other of the axis of the toggle member pivot assaidopposite end shifts between said stops, .acornpression spring having one end connectedto:theswingablc end of said toggle memher and the opposite end connected with said strip adjacentto said opposite end, and an actuating means for moving said toggle member about its pivot, said means having a lost motion connection withsaid toggle memberwhereby said swingable end of the toggle member has limited .free swinging movement from one sicleof the center line of said strip to the other, said spring adapted to react between said toggle.member and strip to urge said opposite end .of said strip to one or the other of saidstops .and .said .swingable end of said toggle member'toitslimit of movement. opposite to the stop engaged by said .strip.

2. A double throw snap acting switch mechanism comprising van elongated strip anchored at one end and having .a contact at the oppositeend, a pair of spaced stops between which saidopposite end of said strip is adapted to shift, a toggle .member extending in the same general direction as said strip, means pivotally supporting one endof said toggle member approximately midway between the ends of said r ,stri-p the other endof said toggle ,member being swingable from one side to the other of the center line ofsaid strip,saidstripbeing adapted totmoveifrom one .side tothe other of the axis of the toggle .member pivot as said opposite end shifts between said stops, a compression spring having one end connected to the swingableend of said toggle member and the opposite .end connected with said strip adjacent to said opposite ,end of said strip, and an actuatingmeans for movingsaid toggle member about its pivot, said means having v.a lost motion connection with said toggle member whereby said swingable end of the toggle member. has limited free swinging movement from one side of the center line of said strip to the-other, said spring adapted to react between said toggle .member and strip to urge said opposite end of said strip to one or the otherof said stops andsaid swingable end of said toggle member to its limit of movement opposite to thestop engaged by ,said strip.

ESTEL C. RANEY.

'RE'EERENCES CITED The'fol1owing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,995,877 -Woodworth Mar. 26, ,1935 2,135,864 Weber Nov. 8, 1938 2,170,748 Eaton Aug. .22, 1939 2,228,523 Johnson Jan. "14, 1941 2,428,1?2 Miller Sept. 30, 1947 2,429,074 'Rugh Oct. 514, 1947 FOREIGN PATENTS Number Country Date 551,021 .Great Britain Feb. A, :1943

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