US2928918A - Snap action switch - Google Patents

Description

March 15, 1960 H. E. PAYNE SNAP ACTION swrrcu Filed Feb. 20. 195'? w 7 JZWIE. y

INVENTOR. H6. PiY Vi HYVWZJYZ'F' SNAP ACTION SWITCH Harold E. Payne, Clark, NJ.

Application February 20, 1957, Serial No. 641,313

' 3 Claims. (Cl. 200-122 This invention relates to a type of relay, more specif ically to a snap action switch whereby a sharp making and breaking of the circuits involved is obtained.

In the past many devices have been designed to accomplish the result of making or breaking circuits. However, these sulfered from certain disadvantages, such as for example undue complexity, sensitivity to shock and inability to function after the casing has been deformed.

It is among the objects of this invention to provide an accurate sensitive relay, which is of fairly simple construction.

It is also among the objects of this invention to provide a relay which is rugged and shock-resistant.

It is further among the objects of this invention to provide a relay which will be operable even though the easing into which it fits is substantially deformed.

In practicing this invention there is provided a base carrying a supporting means consisting of, in one form of the invention, two elements which are fastened at their lower ends to thesaid base and afiixed to each other at their upper ends. In the preferred form of the invention, one element is a rod or channel while the other is composed of two vertical side members spaced apart horizontally and connected at their upper ends by a horizontal cross piece. The aforementioned rod or channel is rigidly connected to the cross piece at a point between the side pieces.

Beneath the cross piece and substantially between the side pieces is placed a rod having means for heating thereof associated with it. The lower end of the heated rod is fixed to the base and the upper end is aflixed to a bar depending from the supporting means. In the preferred form of the invention, the heating means comprises a coil of resistance wire winding around the rod and connected to a source of electrical current.

Also depending from the supporting means is a yoke carrying a contact located preferably near the lower end thereof and which is connected to the bar by means of a spring. The spring comprises a curved strip having one end fixed to the bar and the other end affixed to the yoke so that movement of the bar in one direction causes snap action movement of the yoke in the opposite direction.

On either side of the contact mounted on the yoke are placed two stationary contacts which are so positioned that the movable contact closes a circuit including one or the other, depending upon which position the yoke is in.

In operation, the movable contact is biased so that it touches one of the two stationary contacts. Electrical current flowing through the coil around the heated rod causes the temperature of the rod to rise, thus resulting in a linear expansion thereof. The depending bar is spring biased to the left (as shown in Fig. 2) and is restrained by the rod. Consequently, the rod is always under tension. and. when it is heated. permits the bar to move relative to the stationary members of the relay. When the lower end of the bar has reached a point over center, the action of the spring causes the yoke to move United States Patent 2,928,918 Patented Mar. 15, 1960 ice abruptly in a direction opposite to that taken by the bar. This causes the movable contact to break the circuit formed prior to the heating of the rod and to make contact with the contact point on the other side, thus opening one circuit and closing another.

In the accompanying drawings constituting a part hereof and in which like reference characters indicate like parts,

Fig. l is a perspective view of one form of relay mad according to this invention;

Fig. 2 is a view along line 2-2 of Fig. 1, some parts being omitted for clarity;

Fig. 3 is a sectional view along line 3-3 of Fig. 2, some parts being omitted for clarity, and

Fig. 4 is an enlarged fragmentary view of the end of the bar, the spring and the lower end of the yoke, showing the contact.

Referring particularly to Figs. 1 and 2, there is provided a base 1, a casing 2 of any suitable material mounted thereon, prongs 4 extending below base 1 and having portions 3 extending above base 1 for the purpose of connection with the elements of the relay structure. The supporting means for the structure as a whole is composed of an element 5 having two substantially vertical side pieces 7, an upper cross bar 6 and a lower cross bar and bracket 8, which serves not only to steady suspending member 5 but also to support heated rod 9. The remainder of the supporting means consists of a channel 13 which is secured to cross bar 6. Rod 9 carrying coiled wire 10 is fixed at 11 to member 24 which in turn is fixed to bar 12 which depends from cross bar 6. This provides a connection between the upper end 11 of rod 9 and depending bar 12. Depending from channel 13 is yoke 14 carrying at its lower end movable contact 15. Yoke 14 is provided with a tongue 25 which is inserted into a slot in spring 18. A similar tongue 26 on the lower end of bar 12 is inserted into the other end of spring 18.

Stationary contacts 16 and 17 are positioned so that the movement of yoke 14 will carry contact 15 from one to the other. Stationary contacts 16 and 17 are connected to appropriate terminals 3 by electrical conductors 19 and 20, respectively.

There is provided on channel 13 an adjusting screw 22 mounted in a spring member 23, which member carries yoke 14. By adjusting screw 22, the position of the upper end of yoke 14 is altered. This permits adjustment of the amount of linear expansion or contraction of rod 9 necessary to cause the mechanism to trip.

In operation an electrical current passing through prongs 4, terminals 3 into coil 10 causes rod 9 to rise in temperature and expand longitudinally. This causes upper end 11 of rod 9 to move upward, permitting spring biased depending bar 12 to move to the left, which in turn causes yoke 14 to move to the right as shown in Fig. 2. Thus movable contact 15 snaps from stationary contact 17 to stationary contact 16, thus breaking one circuit and closing another.

Although only one form of this invention has been specifically described, nevertheless it is possible to make numerous changes such as would be apparent to one skilled in the art without departing from the scope thereof. For example, almost any form of supporting means may be used to hold the structure in place with the proviso that it not interfere with the necessary movement of the nonstationary elements. Further, electrical insulation may be provided at certain of the terminals 3 or at other places in the device wherever it is desired to prevent the flow of current.

Still further it is possible to arrange spring 18 so that its curvature is in the horizontal rather than vertical plane,

0 with a corresponding adjustment in the proportions of depending bar 12 and yoke 14. In addition, rod 9 may be heated by any suitable means whether it be an internal coil or simply the passage of electric current through the rod itself. It is possible to manufacture rod 9 of such resistance material that it will generate sufiicient heat for control purposes without the necessity of a coil or wire.

These and other changes in the details of the invention may be made without departing from the principles herein set forth, and the invention is therefore to be broadly construed and not to be limited except by the character of the claims appended hereto.

Iclaim:

l. A snap action switch comprising a a base, supporting means, a rod having means for controlled heating 'thereof, said means for heating consisting of a coil of wire wound around said rod and connected to a source of electric current of suitable voltage and amperage, a bar depending from said supporting means, the upper end yoke, at least one additional contact, said contacts adapted to make and break at least one electrical circuit.

2. A snap action switch according to claim 1 wherein the spring connection is a curved strip having one end afiixed to said bar and the other end atfixed to said yoke so that movement of said bar in one direction causes movement of said yoke in the opposite direction.

3. A snap action switch according to claim 1 wherein there are two additional contacts so positioned that the contact on said yoke reciprocates between said additional contacts alternately closing one circuit and opening the other.

References Cited in the file of this patent UNITED STATES PATENTS 914,684 Warner Mar. 9, 1909 1,215,665 Landis Feb. 15, 1917 2,218,908 Fonseca Oct. 22, 1940 2,429,074 Rugh Oct. 14, 1947 2,700,084 Broekhuysen Jan. 18, 1955 2,769,890 'Hallerberg et a1. Nov. 6, 1956

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