US2481141A - Electrical switch - Google Patents

Description

D. MORRISCN ELECTRICAL SWITCH Filed NOV. 20, 1948 Patented Sept. 6, 1949 TOIFJFlC-E ELECTRICAL SWITCH David Morrison,

Manitowoc, 'Wis., assignor to Paragon Electric Company, Two Rivers, Wis., a corporation of Wiscons ApplicationNovember 20, 1948,*Serial No. 61,205

.The present invention relates to :electrical switches of the type employing. two spring blades that cooperate with each other to make and break .a circuit; and'its object is to produce a simple and .novelswitch mechanism of this type that bothopens and closes witha snapaction.

A further object of the invention is to produce a switch mechanism .thatcan be used for a great many different .purposesandbeadapted for either manual or automatic operation. "The various features of .novelty whereby the present invention:is characterized will hereinafter be pointed outwith particularity in the claims, but, for a full understanding of the invention and of :itsobjects and advantages, reference may behad to the following detailed description taken in connection with the accompanying drawings, wherein:

Figure 1 is a vfront View of a closed switch embodying the present invention, provided with a fingeripiece :for manual operation; Fig. 2 is a viewsimilar to Fig.1, showing the positions of the parts as 'theswitch'is about to open; Fig.3 is a viewsimilar :to Figs. 1 and 2, showing the switch open; ig: 4sis a section on line 4 4 of Fig.5,

showing the operating arm with the switch actuating dog in full and broken lines, respectively, in two different angular positions; Fig.5 is a side view of the switch with the parts in the same positions as in Fig. 1; and :Fig. 6 is a section through the dog and its carrier at the pivotal connection between'the same.

Referring to the drawing, I'll represents a suitable support shown, for convenience, as being -a small slab of insulating material. overlying the support are two 'flat springblades H and 12, each anchored to the support at one end, and standing=on edge parallel to eachotheror, at least, extending in the same general direction. In the particular, form illustrated, one end of each blade is fastened by a screw 13 to a bracket I4, also of insulating material; the bracket, in turn, being fastened to the support. Screws 13 may serve as the switch terminals.

The switch blades may be provided with contact pieces 15 and 16, respectively, for cooperation with each other. The blades are under initial stress so that the contact pieces are normally firmly pressed together, keeping the switch normally closed.

.Eor the purpose of my invention, one of the switch blades, blade II, is longer than the other or, at least, projects somewhat beyond the free end of the same. For operating the switch I provide an actuator that is pressed against the outer side ofithershorter blade 12, and causedzto ride or wipe along the same until it =passesbe-' .yon'd:.the free end ofthat blade. The pressure, while the actuator is in :contact with the shorter blade, bends both blades laterally. Then, when the actuator abruptly releases the. shorter blade, both bladessnap back, but =the'ilonger blade mere 1y drops against :the :actuator and then stops, while the other blade moves farther to open the switch. Aflike snap action is achievedthrough a subsequent switch-closing movement .fOf z th'e actuator.

.The aforesaid actuatorris aifiat dogiiLst-anding on edge, "that is connected by apivot Lpin E18 "to a swinging arm 1:9 fixed'to and projectingradially from (a :shaft 210. The free endof the "dog is out 01f squarely, or, at 1eas't,1there is one :sharpscorn'er I I at what :may'be termed the under edge of the dog. Shaft 20'stands at right angles tothe plane of the support, atsome distance from the switch and facing the short :blade; the shaft being irotatable-and being "adapted to be turned by any suitable means, depending on the use to which the switch is :to be put. In the arrangement shown, the shaft has on its outer end a finger piecezl for manual operation, As bests'hownin .Fig. I4, dog l'l'ha's only a limited angular movement, about relativeto the ammithat carries it; the same long edge of the dog striking a s-motionlimiting element, the form of a pin 2.2 on "the arm, when the dog is turned as far as it will go in either direction. A torsionspringfl, surrounding a projecting part of pivot pin 18, anchored atone end on pin 22 and at the other end in a notch 25 in the tail of the dog, tends constantly to hold the dog against pin 22, :namely in the full line position of Fig. 4. At this time the dogstands almost at right angles to "the arm. .=Bi.vot pin 1:8 islocated at some distancezfrom the free end of arm I9, with that end terminating in .a nose 26.

Projecting from the support, between the shaft 20 and the switch, and at a distance fromthe shafi; substantially greater than the distance "between the shaft and the pivot pin 18, is a stationary stop 21. This stationary stop is at the free endof the short switchblade 12 and is spaced apart from the outer or under side of that blade a dis'tan'ce'no greater than the width of the free end of the actuating dog, although thatdim'en 'sion is not critical. What is important is that when the dog'is in the idle position, as shown in full lines Fig. '4, and not in engagement with with stop 21', turning the s'haftin the direction of the arrowin'Fig. lfcaluses the dog to strike'on the almost at right angles thereto. This operation causes switch blade l2, and therefore blade H which is in engagement therewith, to be bent latorally and thus be placed under considerable :stress. In Fig. 2 the switch-opening movement :almost has been completed, the dog'h'aving been rocked, not only until aligned with the arm, but

a little past center. The nose 26 on the arm is now near the stop so that the shaft can be turned 7 only a little farther although far enough to cause the dog to slip off the end of blade l2; the sharp corner ll insuring a sharp, snap movement away from the cooperating blade. Since blade II has been held up only'because supported by blade 12, it snaps down against the end of the dogimmediately after blade is freed .by the dog, as shown in Fig. 3. Although bothpswitch blades had been deflected equally far by the dog, the latter stops blade ll before it can recoil as far as does blade 12, so that a wide gap is created betweenthe two pieces I5'and l6, leaving the switch wideopen- It will be seen that in Fig. 3, nose 26 on the arm is in engagement: with the stationary stop, while the tail end of the dog engages pin 22 on the arm, Therefore the arm cannot swing farther in the direction that caused the switch to open and, since the dog has been shifted past center, the switch is positively held open.

To close the switch again, the finger piece must be turned in the opposite direction from that in which it moved to open the switch, namely in the clockwise direction as viewed in .Fig; 3. Since spring 24, associated with thedog, is under considerable stress when the switch'is open, this spring and bladell cooperate to hold the dog against the end edge of blade [2 as the arm beins itsv backward movement indicated by the arrow. Since the end of blade l2 now serves as a fulcrum for the dog, the backward or-clockwise movement of the finger piece causes thedog to swing away from the stationary stop Hand to be pulled lengthwise until the sharp corner H reaches the extreme end of blade [2. During this movement blade II is pressing down on the opposite, corner at the free end of the dog. Therefore, when the dog reaches the point where it can drop off the end of blade 12, blade H and spring 24 cooperate to drive the dog down against the stationary stop "as shown in full lines in.Fig. 4--the switch thus closing with a snapaction.

It should be noted that in.Fig. 1 the dog has been moved a little distance away from pin-"22 on the farm; the position of the dog with respect to the arm being that shown in broken lines in Fig. 4. V The arm and dog will not remain in the positions occupied inFig. 1, uponrelease-of .the finger piece, because spring .24 is. sufficiently strong to drive the arm backand allow thedog to engage pin.22 at the end ofthe switch-opening movement. I a I In order to limit the extentof permissible turning movement of. the shaftzand its finger piece through an angle not substantially greater than that required to open and close. the switch, and avoid lost motion, a second stationary stop may be provided for arresting backward movement of the dog-carrying arm immediately after the switch opens. In the arrangement shown, there is such a stationary stop 28 on the supporting member 10, in position to be engaged by the arm when the latter is swung back a little from its position in Fig. 1, with the dog still resting onstop 21, however.

It-will thus be seen that I have produced a simple and novel switch mechanism wherein there is a snap action both in opening and in closing a circuit. It will furthermore be seen that only a small angular movement of the ope'rating'shaft isxrequired to open or close the switch; a comparison of Figs. 1 and 3 showing that the finger needs travel through an angle ,of only about 45 to shift from a closed state to a wide open state. Therefore my improved mechanism lends itself admirably to use in many situations where the operation of a switch by turning a shaft through a small angle isadvantageous or'even essential. i gwhil'e Iv have illustrated and described with particularityonl a single preferred form ofmy'invention, I do not desire to be limited to the-exact details thus illustrated and described, but intend to cover all forms and arrangements that come within the definitions of my invention constituting the appended claims.

I claim: v 1. In combination, a normally closed switch having two spring blades extending in thesame general direction and each anchored atone end and free at the other end, the free end of one blade projecting outwardly beyond the free end of the second blade, lan actuating dog so placed that the second blade lies between the same and the first blade; said dog having three positions, namely an idle position, a :position in which it engages the second blade andxpresses both blades laterally, and a third position wherein it is clear of the second blade :and serves as a stop for the projecting end of the first blade; a swinging arm, a pivotalconnection between one end of the do and said arm, a spring tending constantly to keep the dog in the idle position when the dog is moved bythe arm, and astationar'y stop in posi-. tion to be engaged by said dog and cause it to swing into its secondand third-positions when the arm is swung in one direction. 2. The combination set forth in claim 1, where; in the swinging arm is provided with a part that engages the stationary stop as the dogreaches its third position. I Y -3. The combination set forth in claim 1,-wherein the swinging arm is provided with a part that engagesv the stationary stop at the time that the dog reaches its third position, and the dog and the arm are on about the same radius with respect to the pivotal axis of the arm when both are; in engagement with the stationary stop. 1 4. Incombination, a normally closed switch having two spring blades extending in the same general direction and each anchored at one end andfree atthe other end, the free endof one blade projecting outwardly beyond the free end of the second blade, a stationary stop so positioned near the free end of and in spaced'relation to .thesecond blade that the latter liesbetween the same and the first blade; an arm mounted to swing into engagement .with and away from said stop, a dog mounted at one end on thefree end of said arm for movements between a normal. position in which it extends laterally from said arm toward said Stop anda second position wherein it extends lengthwise of the arm and projects beyond the free end of the latter, and a spring tending constantly to hold the dog in its normal position; the parts being so proportioned that the dog rides on the stop, as the arm approaches the latter, and is gradually forced out of its normal position into its second position, with the free end of the dog first engaging the second blade, and pressing both blades laterally, and then passing beyond the free end of the second blade as the dog reaches its said second position.

5. In combination, a normally closed switch having two parallel spring blades each anchored at one end and free at the other end, the free end of one blade projecting outwardly beyond the free end of the second blade, a stationary stop so positioned near the free end of and in spaced relation to the second blade that the latter lies between the same and the first blade; an arm mounted to swing into engagement with and away from said stop, a dog mounted at one end on the free end of said arm for rocking movements between a normal position in which it extends laterally from said arm toward said stop and a second position wherein it extends lengthwise of the arm, slightly past center, and projects beyond the free end of the latter, and a spring tending constantly to hold the dog in its normal position; the distance between the axis about which the dog rocks and the pivotal axis of the arm being less than the distance between the latter axis and the stationary stop whereby, as the arm is swung toward the stop, the latter serves as a fulcrum on which the dog turns from one extreme position to the other.

6. In combination, a normally closed switch having two parallel spring blades each anchored at one end and free at the other end, the free end of one blade projecting outwardly beyond the free end of the second blade, an arm pivotally mounted at one side of the switch and facing the second blade, with its pivotal axis spaced apart from the switch a distance greater than the length of the arm, a stationary stop located between the said pivotal axis and the switch and in position to engage the arm near its free end when the arm is at one end of its angular movement, a dog pivoted at one end to the arm at a distance from the said pivotal axis substantially less than the distance between that axis and the stationary stop, an element on the arm to engage the dog and limit its swinging movement on the arm in one direction to a position in which the dog is crosswise of the arm with its free end in position to travel up over said stationary stop when the arm is swung toward the latter, a spring tending constantly to hold said dog against said limiting element, said dog having at its free end an edge to engage with the free end edge of the second blade as it approaches the same and terminating in a sharp corner outwardly from the latter blade; the parts being so proportioned that when the arm is swung against the stationary stop the dog is caused to rock on the stop and press both switch blades farther away from the stop and then to wipe along the second blade and move on past the end edge at the free end of the latter to a point under the projecting end of the other blade.

7. In combination, a normally closed switch having two parallel spring blades each anchored at one end and free at the other end, the free end of one blade projecting outwardly beyond the free end of the second blade, an arm pivotally mounted at one side of the switch and facing the second blade, with its pivotal axis spaced apart from the switch a distance greater than the length of the arm, a stationary stop located between the said pivotal axis and the switch and in position to engage the arm near its free end when the arm is at one end of its angular movement, a dog pivoted at one end to the arm at a distance from the said pivotal axis substantially less than the distance between that axis and the stationary stop; an element on the arm to engage the dog and limit its swinging movements on the arm between a normal position, in which the dog is crosswise of the arm with its free end adapted to travel up over said stationary stop when the arm is swung toward the latter, and a second position, wherein the dog has been shifted into, and then a little beyond, alignment with the arm; a spring tending constantly to hold said dog in said normal position; said dog having at its free end an edge to engage with the free end edge of the second blade and terminating in a sharp corner outwardly from that blade; the parts being so proportioned that when the arm is swung toward the stationary stop the dog is caused to rock on the stop, press both switch blades farther away from the stop, and then slide along the second blade and oiT the free end of the latter so as to stand in its said second position under the projecting end of the other blade, as the arm moves into engagement with the stationary stop.

DAVID MORRISON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,102,639 Benjamin July '7, 1914 1,320,879 Litter Nov. 4, 1919 1,447,171 Benjamin et al Mar. 6, 1923 1,768,943 Taylor July 1, 1930

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