US2901568A - Snap-action switch - Google Patents

Description

Aug. 25, 1959 J. B. GOFF 2,901,568

SNAP-ACTION SWITCH Filed April 26, 1957 A/OPMAL L Y OPE/V NOPMALLY O NOOAI IZIVLLY We 6 INVENTOR. JUST/N BGOFF AL'OFNEXS I o IVOPMALZ Y COMMON United States Patent SNAP-ACTION SWITCH Justin B..G0lf,' Indianapolis, Ind.

Application April 26, 1957, Serial No. 655,308

2 Claims. (Cl..20 0--'67) The present invention relates to electric switchesand more particularly to a snap-action switch that has a neutral position. The switch disclosed herein has particular advantage in that two or more circuits can be controlled by a single switch and one circuit can be opened or closed, as the case may be, before another circuit is affected.

Many sizes and varieties ofelectric switches are presently being employed to control industrial machinery and equipment and, likewise, many small precision switches are being used in electronic equipment to perform many switching functions.

Heretofore there hasnot been known any single snapaction switch having a neutral position although there has been a need for such a switch. One method of accomplishing the same function of the present invention has been to assemble two single pole, double throw switches in a metal-mounting bracket and to provide a self-centering toggle lever between the two switches. Movement of the lever in either direction operates one of the switches, and upon release of the lever the switch circuits are, returned to their normal condition.

The heretofore known method of employing two switches mounted together was expensive and, additionally, required a relatively large amount of space that often is critical, particularly in airborne equipment. In addition, the heretofore known arrangement required one circuit to be returned to its normal condition before the other circuit could be closed or opened, as the case may be, and thus the assembly did not lend itself to controlling a sequence of operations.

The present invention comprises a single snap-action switch having a neutral position and in a basic embodiment would have one normally closed switch and one normally opened switch. Movement of a plunger a predetermined amount will open the normally closed switch and additional movement of the plunger in the same direction will close the normally open switch. Thus it can be seen that a sequence of operations can be performed by the present invention.

An object of the present invention is to provide a small, compact, snap-action switch which may be manufactured economically.

Another object of the present invention is to provide a snap-action switch having a neutral position.

Other objects and advantages of the present invention will be readily apparent from the following detailed description when considered in connection with the accompanying drawing wherein:

Figure 1 is a wide view of a switch embodying the principal features of the present invention;

Figure 2 is an enlarged sectional view taken on lines 2-2 of Figure 1;

Figure 3 is a top view of another embodiment of the present invention;

Figure 4 is a sectional view taken on lines 44 of Figure 3;

Figure 5 is a diagram showing a contact arrangement of a preferred embodiment of the present invention; and

Figure 6 is a diagram showing a contact arrangement of another embodiment of the present invention.

Referring now to the drawing, there is shown in Fig.- ures l and 2 a preferred embodiment of the present invention which comprises a base 10 of suitable insulating material and a cover 11. The base and cover may be, although not necessarily, molded of a thermosetting plastic material, and the cover 11 is secured to the base 10 by any suitable means (not shown). A pair of resilient biasing members 12 and 13, having contacts 14 and 15, respectively, are mounted within the base 10 by means of a screw 16 that threadedly engages a metallic bushing 17 in the base 10. The resilient biasing members 12 and 13 have a tension leaf 18 and a pair of compression leaves 19 that are pivotally mounted in a V-notch 21 in members 22.

Referring more particularly to Figure 2 of the drawing, it can be seen that the resilient biasing member 12 biases contact 14 against an upper stationary contact 23 to provide a normally closed contact arrangement. Likewise, the resilient biasing member 13.biases the contact 15 upward and away from the lower stationary contact 24 to provide a normally opened contact arrangement, as shown in Figure 5 of the drawing.

As shown, a plunger 25 passes through the cover 11 and is in engagingv contact with the tension. leaf 18 of resilient member 12. A button 26 is secured, by any suitable means, to the bottom side of the tension leaf 18, and when the resilient biasing member 12 is depressed, button 26 comes into slidable engaging contact with. the tension leaf of resilient biasing member 13. A stop pin 27 which, by way of example, may be secured to the two, side walls of the base 10, serves as a stop to limit both, the downward travel of resilient biasing member 12 and the upward travel of resilient biasing member 13.

The operation of the heretofore described embodiment: can readily be understood by reference to Figures 2,.and5: of the drawing. When the switch is not being actuated, the resilient biasing, member 12 biases contact 14 against the upper stationary contact 23 to provide a normally closed contact arrangement, and, in addition, the resilient biasing member 12 biases the plunger 25 upward. Upon actuation of the plunger 25 in a downward direction, the resilient biasing member 12 operates with a snap action to break contact between the contact 14 and the upper stationary contact 23. The downward movement of resilient biasing member 12 is retarded by stop pin 27 and button 26 is contacting the resilient member 13. Additional downward movement of pin 25 will cause the resilient biasing member 12 to bow in the middle section, as both ends are constrained, and this bowing action permits button 26 to actuate resilient biasing member 13 with a snap action causing contact 15 to engage the lower stationary contact 24.

Upon release of the actuating force from plunger 25, resilient biasing member 13 is permitted to snap back to its original position and contact between contact 15 and lower stationary contact 24 is broken. Likewise, resilient biasing member 12 is permitted to snap back to its original position, and contact is again made between contact 14 and upper stationary contact 23. It can thus be seen that the normally closed circuit is first opened and the normally opened circuit is then closed upon actuation of plunger 25 in a downward movement. Thus the switch can be used as a safety device, for example, to assure that one element or component is taken out of circuit before another is switched into the same circuit. Of course, the embodiment shown in Figure 2 can likewise serve as a switch for two entirely diiferent circuits or can serve either as a normally open or a normally closed switch in a single circuit by merely connecting a lead to the common contact and the desired stationary contact 23 or 24.

Another embodiment of the present invention is shown in Figures 4 and 6 of the drawings wherein the stop pin 27, which serves as a stop in the embodiment of Figure 2, is replaced by a contact assembly 28. This assembly serves as a stop to limit the downward travel of resilient member 12, but in addition has contact terminals 29 and 30 that respectively are engageable with contacts 31 and 32 that can be biased against them.

As shown in Figure 6 of the drawing, it may be desirable to use the switch shown in Figure 4 to control separate circuits and thus it may be desirable to keep the biasing members 12 and 13 from making electrical contact with each other. This can readily be accomplished by making the button 26 from an insulating material, such as nylon or Teflon, and by providing an insulating bushing 33 and an insulating washer 34. Terminals 35 and 36 might be, by way of example, integral with the biasing members 12 and 13, respectively.

The sequence of operation is similar to the operation of the embodiment of Figure 2 and, as can be seen, actuation of plunger 25 in a downward movement first causes contact between contact 14 and upper stationary contact 23 to be broken, and then contact is made between contact 31 and contact terminal 29. Additional downward movement of plunger 25 causes button 26 to actuate resilient member 13, thus breaking electrical contact between contact 32 and contact terminal 30 and making electrical contact between contact 15 and lower stationary contact 24. Release of the actuating pressure on plunger 25 permits the resilient members 12 and 13 to return to their original position and the contacts are aiTected in a reverse order; that is, electrical contact between contact 15 and lower stationary contact 24 is first broken, then contact is made between contact 32 and terminal 30, next electrical contact is broken between terminal 29 and contact 31, and finally electrical contact is made between contact 14 and upper stationary contact 23.

From the foregoing description it should be readily apparent that the embodiments of the present invention have particular merit over heretofore available switches. For example, a single switch of the present invention can be used to replace from two to four ordinary snap switches and also assure that a plurality of circuits can be switched or affected in sequence.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A snap-action switch comprising, a base, a plurality of stationary contacts attached to said base, first and second movable contacting means each having a tension leaf and a pair of compression leaves, and having one end attached to said base and adaptable for engaging corresponding stationary contacts, a stationary abutting means intermediate said first and second movable contacting means for limiting travel of said first and second movable contacting means, a plunger for actuating said first movable contacting means between one of said stationary contacts and said stationary abutting means, and means on said first movable contacting means for actuating the other said movable contacting means when said first movable contacting means is engaged with said stationary abutting means.

2. A snap-action switch as set forth in claim 1 wherein said means on said first movable contacting means for actuating said second movable contacting means comprises a button attached to said first movable contacting means and adaptable for slidably engaging said second movable contacting means.

References Cited in the file of this patent UNITED STATES PATENTS 2,284,816 Harrington et al. June 2, 1942 2,354,027 Kaminky July 18, 1944 2,385,858 Horman Oct. 2, 1945 2,498,569 Mork Feb. 21, 1950 2,586,992 Rapuano Feb. 26, 1952 2,644,052 Martin June 30, 1953 2,750,463 Roeser June 12, 1956 2,754,390 Diesen et al July 10, 1956 2,774,836 Powers Dec. 18, 1956 2,763,737 Barber Sept. 18, 1956 FOREIGN PATENTS 126,654 Australia Feb. 5, 1945

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