US2272021A - Snap switch - Google Patents

Description

Feb. 3, 1942. v A. L. RICHE 2,272,021

. SNAP SWITCH Original Filed Nov. 30, 1938 T i 94 49 l 10@ M I UVJULA 770A Patented; ,Feb. 3, 1942 Arthur L. Riche, Freeport, 111., assignor to Micro Switch Corporation, Freeport, 111., a corporation'ot Illinois Original application November 30, 1938, Serial No. 243,286, new Patent No. 2,236,699, dated April 1, 1941.

Divided and this application August 3, 1940, Serial No. 350,306 K (or. zoo-13s) 7 Claims.

This invention relates to improvements in snap switches and more particularly to improvements in the snap switch forming the subject matter of McGall Patent No. 1,960,020, issued May 22, 1934.

This application is a division of my application Serial No. 243,286, filed November 30, 1938, now

Patent No. 2,236,699, issued April 1, 1941, which in turn constituted a continuation in part of my application Serial No. 52,778, filed December 4, 1935.

It is an object of this invention to provide a compact and serviceable snap switch of the Mo- Gall type especially adapted for use in conjunction with thermostatic metal.

The specification is to be read in conjunction with the appended drawing which illustrates a specific embodiment of my invention, and in which:

Fig. 1 shows a specific type of switch including my invention; and,

Fig. 2 is a view of the combined compression and tension' element of Fig. 1.

In the thermostatic switch construction of Fig. 1, the entire mechanism is supported upon an insulating base 80. A thermostatic metal strip 82, subject to the heating effect of a coil 84 is mounted in cantilever fashion on post 85 which in turn is supported on the base 80. Attached to the unmounted end of the thermostatic member 82 is a stud 86 which is provided with a necked portion 88, and also an anchor bracket '98 having a notched portion 96. The spring snap element comprises a tension member 90 "and a pair of bowed compression springs 94, which are pivotally supported on the necked part of stud I 86 and the notch 90 'of the anchor bracket 98.

The tension and compression members 90 and 94 may conveniently bestamped out of one piece of thin sheet spring material such as phosphorbronze, beryllium bronze or the like, so that the tension and compression members constitute sprinsgzstrips connected together at their movable end tension and compression strips are such that ,when the spring is mounted on the stud 86 and bracket 98, the compression springs 94 are, bowed in compression as shown so that the spring, with its tension and compression members 90 and 94, constitutes a snap acting spring toggle. This toggle spring carries a weight I09 at the movable end 92.

A loosely mountediron or other magnetic pendulum like member I is suspended from a. suit able stud support 102 which is mounted on the base 80. The pendulum like member I00 is turned back on itself at its lower end to provide a U-shaped portion, the legs of which constitute spaced apart stops for the toggle spring with its weight I09. Attached to the bottom part of the pendulum like member I00 is a contact I04 which bridges a pair of stationary electric contacts I06, only one of which is shown in the drawing. A magnet I08 is mounted on the base and spaced vfrom the pendulum I00. The magnet tends to attract the pendulum and thus it insures good electrical connection of the bridging contact I04 with the two stationary contacts I06. It is obvious that the magnet may be mounted on the pendulum and that member I08 may be attracted thereby. When heated by the coil 84, the thermostatic metal strip 82 bows outwardly so that the tension center line of the tension strip 1s carried across the axis of the pivot 90 of the compression springs 94 to thereby cause the connected end 92 with its attached weight I09 to snap over and hit a hammer like blow on the backwardly turned part IIO of the pendulum I00. This blow, in combination with the decrease in magnetic pull resulting from the increased separation of the iron pendulum I 00 from the magnet I08, quickly separates the bridging contact I04 from the two stationary contacts I06 to break theelectrical circuit. This break is rap d part IIO lying against the stop II2 thereby holding the contacts apart until the thermostatic strip 82 cools and the switch thereupon returns with a snap action to the original position so that electrical contact is restored.

When th switch operates, the relative positions of the combined mounting points of the compression and tension members change with respect to the stops, the change of relative positions of both mounting points with respect to the stops being in the same general direction. Furthermore, the change of relative position of the stops with respect to the mounting points of the tension member is at least as great as the change of the relative position of the stops with respect to the mounting points of the compression memunder certain conditions modified constructions may be employed, whereby the substantial equiv alent of a pivot action is obtained. However, when reference is made in the claims to the snapping o! the switch when the pivot point passes through the tension center line, it is intended to include modified constructions, wherein substantially that action takes place although a small deviation therefrom may occur.

Various modifications may be made of the construction described herein without departing from the scope of the appended claims.

I claim:

l. A snap switch comprising in combination, a tension member and an adjacent compression member each operatively mounted at one end and connected together at their opposite ends which are free to move, a loosely mounted magnetic pendulum like member having a U shaped end portion with the inner surfaces of the legs of the U constituting stops between which said connected end parts move, at least one of said tension and compression members comprising spring means, said compression member being mounted operatively at a point whereby it has a diflerent radius of action than said tension memher, said mounting point of said compression member and tension center line of said tension member being movable with respect to each other,

a stationary electric contact, an electrical con-' tact on the exterior side of one leg of said U shaped portion of said pendulum like member pressing against the stationary electrical: contact, a magnet contiguous to and in such -relation to said pendulum like member as to tend to hold said two contacts together, said connected end portion of said tension and compression members pressing against the electrical contact spect to eachother being changeable, the change of relative position of both said mounting points with respect to said stops being in the same general direction, said change of relative position of said stops with respect to said mounting point the tension member being at least as great as the change of relative position of said stops with respect to said mounting point of said compression member, said tension and compression mem' bers and the switch as a whole being so constructed and arranged that the change 01' the relative position of the tension and compression member mounting points with respect to said stops causes the tension center line to move across the compression member mounting point and thereby causes said connected end portion of said tension and compression members to snap over with suflicient force against the opposite leg or stop of said U-shaped portion so that the pull of said magnet on said pendulum like member is overcome and said contacts are separated, thereby breaking the electrical circuit controlled thereby.

2. A- thermostatically operated snap switch comprising in combination a strip of multilayered thermostatic metal mounted at one end thereof with the other end free to move with changes in temperature thereof, a tension'member operatively mounted at the free end of said thermostatic strip with its opposite and tree to move and extending toward the mounted end of said strip, a spring compression member adjacent said tension member and connected to the tree compression members and or said stops with reend between the mounted and-connected ends of said tension member and at the free end of said thermostatic strip, the mounted ends of both said tension and compression members being so connected to the free end of said strip as to move therewith as the temperature thereof changes, stops between which said connected end portion of said compression and tension members moves, said members being so constructed and arranged that said connected endportion moves with a snap action between said stops as said compression member mounting point and said tension member center line cross, said stops being formed by the inner surfaces of the legs of a U-shaped end portion 01 a loosely-mounted magnetic pendulum-like member, an electrical, contactv on the exterior side of one leg of said U-shaped end portion and pressing against stationary electrical contacts, said stationary contacts controlling an electrical circuit, a magnet contiguous to andin such relation to said pendulum-like member as to tend to hold said contacts together, said connected end portion pressing against the electrical contact leg of said U-shaped part when said contacts abut each other, said switch being so constructed and arranged that when said compression member mounting'point crosses said tension center line said connected end portion snaps over with suilicient force against the opposite leg or stop that the pull of said magnet on said pendulum-like member is overcome and said contacts are separated thereby breaking the electrical circuit through said stationary contacts.

3. A snap switch comprising in combination, a tension member and an adjacent compression member, each operatively mounted at one end and connected together at their opposite ends which radius of action than said tension member, said mounting point of said compression member and the tension center line of said tension member being movable with respect to each other, said tension and compression members being so constructed and arranged that said connected end portion moves with a snap action as said compression member mounting point and said tension member'tension center line cross, the relative positionof the combined mounting points ofsaldtension and compression members and of said stops with respect to each other being changeable, the change of relative position of both said mounting points with respect to said stops being in the same general direction, said change of relative position of said stops with respect to said mounting point of said tension member being at least as great as the change of relative position of said stops with respect to said mounting point'of said compression member, one of said stops comprising magnetic material, a'magnet contiguous to said magnetic material in one position and tending to hold the stop associated therewith in said position, said connected end portion also pressing against said stop to urge it toward said magnet and being of sufllcient weight and said snap switch being so constructed that a hammer-blow is directed against the opposite stop when said switch end thereof and pivotally mounted at its other snaps over, the force of the blow being suillcient to overcome the magnetic attraction between said contigous magnetic members.

4. In an electric oontactor, fixed and movable contacts, a carrier on which 'the movable contact is mounted, the carrier being movable between two extreme positions in one of which the contacts are engaged to complete a circuit and in the other of which the contacts are separated to break the circuit, a portion of the carrier serving as an armature, a magnet positioned to attract the armature and tend to hold the contacts in engagement with one another, and a snap-spring mechanism having limited freedom of movement with respect to the carrier but adapted to engage the carrier after the snap-spring mechanism has passed a substantial distance beyond its deadcenter position in either direction and thereaiter shift the carrier from one to the other of its extreme positions.

5. In an electric contactor, fixed and movable contacts, a carrier on which the movable contact is mounted, the carrier being movable between two extreme positions in one of which the contests are engaged to complete a circuit and in the other of which the contacts ar 'separated to break the circuit, a portion of the carrier serving as an armature, a magnet positioned to attract the armature and tend to hold the contacts in engagement with one another, and a snap-spring mechanism having a free end portion adapted to snap to one or another of two opposed positions when moved past a dead-center position, said end portion being movable between a pair of spaced apart portions of the carrier so as to forcibly engage one of these portions and move the.

carrier' to one or the other of its extreme positions after the said end portion of the snap-spring.

mechanism has passed its dead-center position.

6. In an electric contactonfixed and movable contacts, a magnetic detent normally tending to hold the contacts in engagement to complete a circuit, and a snap-spring mechanism having a lost-motion connection with one of the contacts whereby the snap-spring mechanism may be moved a substantial distance beyond its dead center position and will thereafter engage and move the contactto break the circuit.

'7. A snap switch comprisin in combination, an elongated member operatively mounted at one end with the opposite end free to move, stops between which said free end moves, said switch being so constructed that said free end moves from one stop to theother with a snap action, said stops being movable in the direction of movement of said free end portion, one of said stops comprising magnetic material, a magnet contiguous to said magnetic material in one position and tending to hold th stop associated therewith in said position, said free end portion also pressing against said stop to urge it toward said magnet and being of suflicient weight and said snap switch being so constructed that a hammer-blow is directed against the opposite stop when said switch snaps over, the force of the blow being 'suflicient to overcome th magnetic attraction between said contiguous magnetic members ARTHUR L. RICHE.

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