US2246724A - Electric switch - Google Patents

Description

June 24, 1941. M w, EATON 4 2,246,724

. ELECTRIC SWITCH Original Filed Dec. 4, 1955 Patented June 24, 19 41 UNITED STATES PATENT OFFICE Malcolm w. Eaton, Freeport, m, asaignor to Micro Switch Ooflrroration, Freeport, 11L, a corporation oi Illin Original application December 4,1935, Serial. No.

52,771, new Patent No.

22, 1939. Divided and this 21, 1939, Serial No. 291,160. 1

2,170,748, dated Au ust application August 3 Claims. (01. 200-47) This invention relates to snap switches, and more particularly to electrically operated switch mechanisms for timing periodical occurrences.

This application is a division my co-pending application, Serial No. 52,771, died December 4, 1935', now Patent No. 2,170,748, issued August 22, 1939.

Objects of the invention include the provision 01' a switch that requires a. minimum of power through said electric magnet; and

Fig. 2v is a partial plan oi view of the device of Fig. 1 showing the switch mechanism and the general arrangement of the movable elements The construction shown in-the drawing may be used wherever it is desirable to secure controlled intermittent passage 0! electric current. The specific application shown is for the operation of a flasher device in which a neon-filled tube or other partially evacuated or fluorescent tube is used. InFls. 1 the switch is combined with an induction coil and is operated bythe magnetic iield thereof by means of an armaturemounted upon an element 01 the switch. The snap switch is mounted directly on the electromagnet oi the induction coil which is used to step up the voltage to that required to flash the luminous tube operated thereby. I Since the source of energy is unldirectional, ior example, that supplied by a primary or secondary battery, means are provided more is rugged, economical to operate and has a minimum 01' moving parts.

. m the electromasnet shown in m. 1 the windings 2| set up a magnetic iield in the laminated iron core 12. The switch mechanism is mounted above it upon the brass or other non-magnetic base member 24 attached to the core and cross members 28 and II. The contact end of the ,switch is mounted upon the frame cross member,

28 which iorms one side oi the circuit. Upon this cross member is attached in cantilever ia-shion a switch actuator consisting of i strip spring member 30 which extends rearwardly as shown. Other equivalent constructions having of vibration may be an inherent natural period used in place oi the cantilever mounted strip spring. For example, I may employ a still strip member hinged at I! and mounted at its opposite end upon a coiled or other suitable spring whereby the still! strip vibrates when released after for interrupting the energy supply in order to produce pulsations in the primary oi the induction coil whereby therequired higher voltages are induced in the secondary thereof. In flashing devices of this type, especially when they are used for roadside warning signs, it is desirable to have the device flash at comparatively long intervals of time, say one flash every one' hali" to three seconds, it being necessary. further tube able to control exactly the timing of these flashes.

flexing the spring either in compression or tension. At the opposite end and bottom of said strip 30 is attached a magnetic armature, 32

which is spaced from the core 22. The core is.

slotted at 34 under the armatureto, provide the leakage flux required for increasing the eillciencyw ofthe magnetic action on the armature. The cross member 28 carries a vertical adjusting stud II on which is supported the tension strip or 101-, lower a of the snap switch. As shown the stud has a necked portion 40 which fits into opening 4! (see Fig. 2) oi the tension strip. The opposite iree endoi said tension member is attached to compression spring 44 and contact 40 is mounted thereon. The opposite end 0! compression spring 44 is pivoted in a notch 48 which is formed in a mounting member 49 on said cantilever spring strip. 30. Notch 48 is normally (when said switch is not operating). above the tension center line of said tension strip 38 so that contact 46 is normally pressing against the lower stop 50. An important feature of this construction is that the bottom part 01' the bow of compression spring 44 constitutes a bumper and normally just touches spring strip 30 or lies in close proximity thereto. The lower stop 50 is an electrical contact which is insulated from the rest of the switch and frame except through contact 46 and either or both the connecting tension strip 38 and compression spring 44. The circuit from the source of electrical energy therefore passes through contacts 46 and 50, through the energizing coils and back .to the source of energy. An upper stop 52' may be used to limit the upward movement of contact 46.

Sincethe contacts 46 and 66 are normally pressing against each other, the electromagnet 26 becomes energized when a source of energy is applied across the terminals of the primary notch 46 drops, and the pivot point of compression spring 44 thus drops below the tension center line of tension member 36. This forces the free end of the compression spring and contact 46 to move upwardly with a snap from contact- 50, simultaneously breaking the electrical circuit and inducing a sufficient voltage in the secondary to cause a space discharge in a gas-filled tube (not-shown), such as a neon tube,'in circuit therewith. A distinct bright flash thereupon occurs in said tube. 'Ihe electromagnet is deenergized immediately so that it releases armature 32. Spring strip in and armature- 32 then spring upward and in so doing move the notched member 46 up to carry the pivot point of the compression spring 44 above the tension center line of the tension member 66 and to force the contact 46 to move with a snap action down against the stationary contact 50. Because of the inertia oi the combined spring strip 80 and armature 32 this combination member does not come to rest immediately at the normal place but travels upwardly past the normal position. As it passes upwardly through the normal position,

circuit probably is closed for a comparatively minute le h of time as the device passes through the normal position. After the vibrator,.

that is, combined spring 36 and armature 62, has reached the upper limit 01' movement due to its inertia, the flexed strip spring 66 causes this vibrating member to, travel downward again. The'weighted cantilever spring or actuator 36 continues for a time to vibrate with decreasing amplitude and in .so vibrating beats against bowed compression spring 44 to lift the contact 46 repeatedly oi! the contact 66. During this oscillation of the cantilever actuator 36, contact 46 never lies in engagement with contact 56 long enough at one time to produce a distinct bright low intensity flashes follow each other with sulficient rapidity that the tube glows as steadily as when a 60 cycle alternating. current is applied to the tube. The tube may glow with suflicient intensity with certain gases so that it may be used for purposes where a continuous lower intensity illumination is desirable. The apparently continuous glow has, of course, a bright flash passing through it each time when the circult is broken after contact 46 comes to rest against contact 66, but not during the period when the oscillation are diminishing in amplitude as explained previously. The characteristics of the device may be changed by changing the proportions and setting or the various parts as by raising or lowering the point oi support 40 of the tension member 38 by means of stud 26. The interval between flashes may be varieda variation in flasher speeds of from one every three seconds or greater to a "flutter."

Throughout the specification the directional' terms horizontal, vertical, below, above, etc. are

used for convenience, and to facilitate the description, and are not used in a restrictive sense. It is obvious from the description that a reference to a vertical movement refers to a generally up or down movement.

The invention is not limited to the specific construction herein shown and described by way of illustration and example, but rather contemplates variations thereoi without departing from the invention as recited in the appended claims.

I claim:

1. In combinationin a toggle snap switch; an actuator having a natural period of vibration and having also a normal rest position, a snap follower, an electric contact carried by said follower, a stationary contact adapted to cooperate with the contact carried by the follower, and spring means for operating the snap follower in response to an operation of said actuator. said follower and said spring means including a bumper portion which said actuator is adapted to engage to separate saidv contacts without snapping said switch, said elements being so constructed and arranged that said contact normally engage each other, and that said actuator normally lies alongside said bumper portion without thereby holding said contacts out of engagement, said actuator being adapted to be moved out of its normal position and away from said bumper to snap said toggle switch to disengage aid contacts, said actuator being further constructed and arranged so that when released,-

it first returns towards its normal position to snap said toggle switch to bring said contacts into engagement and then vibrates about its normal position, and in so vibrating beats against said bumper to separate said contacts without again snapping said toggle switch.

2. The combination of the inmiediat iy preceding claim wherein said follower comprises a tension member and said spring means comprises a thin leaf spring strip bowed in longitudinal compression adjacent said tension member, wherein said spring means connects said follower and said actuator, and wherein the convex face of said bowed spring strip constitutes said bumper portion.

3. In combination in a spring snap switch, a snapping element including a spring, an electric contact carried thereby, a second electric contact cooperating with the contact carried by the snapping element to open and close a circuit, a vibratory actuator for said snapp ng element having a natural period of vibration and also a rest position, and constructed and arranged to actuate said snapping element with a snap action to separate said contacts when said actuator moves in one direction out of said rest position and means cooperating with said actuator to actuate said snap element to reclose said contacts when said actuator return from said one direction to said rest position, said snapping element having a bumper portion that said actuator engages when moving out of said rest position in the opposite direction to separate said contacts without snapping said snap element.

MALCOLM W. EATON.

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