US3170999A - Silent magnetically operated snapaction electric switch - Google Patents

Description

Feb. 23, 1965 L. R. BROWN SILENT MAGNETICALLY OPERATED SNAP-ACTION ELECTRIC SWITCH Filed April 18, 1963 III/I/I/I/III/III/IT FIGURE 3 FIGURE 2 FIGURE 4 INVENTOR Mam United States Patent 3,170,999 SILENT MAGNETICALLY OPERATED SNAP- ACTION ELECTRIC SWITCH Laurence R. Brown, 8103 Bardu Court, Springfield, Va. Filed Apr. 18, 1963, Ser. No. 273,984 2 Claims. (Cl. 200-67) This invention relates to snap switches and more particularly it relates to toggle switches adapted for use in house wiring systems.

One problem with snap switches as used in house wiring systems is the loud snap noise encountered. Thus,

when turning out a light in a babys room, the snap may awaken the baby. To overcome this noiseless mercury switches have been introduced. Their shortcomings however have prevented satisfactory operation. The mercury tends to oxidize when encountering sparks on the make and break action. These arcs are drawn out because of the lack of snap action. Also mercury switches must be oriented in a special way to work.

Accordingly it is an object of this invention to psovide a substantially noiseless snap switch.

Another object is to produce an improved and simplified switch readily assembled with few parts.

A general object of the invention is to provide an improved snap switch useful for house wiring systems.

In accordance with the invention, snap action is obtained by use of a single permanent magnet which is moved by the toggle arm. It holds the switch in two stable positions with enough force that a definite snap action is afforded in a change of position to cause the fast break and fast make operations desirable to prevent excessive arcing in the switch. The action may be likened to the snapping of a middle finger on the palm from a position on the extended thumb. The snap action is evident from the noise generated. In the switch however the snap noise is significantly reduced by covering the magnet with a thin layer of acoustically absorbent material.

The invention together with further features and advantages is described in connection with the accompanying drawing wherein:

FIGURE 1 is a sketch of a switching arrangement that may be employed in the invention;

FIGURE 2 is a sketch, partly in section, of a toggle assembly afforded in one embodiment of the invention;

FIGURE 3 is an assembly view, partly in section of a switch constructed in accordance with the principle of the invention; and

FIGURE 4 shows permanent magnets of the type which may be used in accordance with the invention.

In the drawing some of the dimensions are exaggerated to illustrate features of the invention. All views are explained in conjunction to show how the parts interrelate in the various figures.

Basically, the invention uses a single magnet 10, mounted in a toggle lever assembly 12 for motion therewith to produce a snap holding action when substantially contacting ferromagnetic terminal elements 14 and 16 in respective ones of the stable rest positions of the toggle.

The switch illustrated is a simple on-olf switch, but other switching arrangements may be incorporated, if desired. Switching blade 17 pivots from a shaft bearing hole 18 about a toggle pin shaft 19 at pivot points 20 and 22. The blade may be constructed in part or entirety of beryllium copper for example, which is indented at posi- 3,170,999 Patented Feb. 23, 1965 tions 23 and 25 to provide contact ridges. These contact ridges 23 and 25 mate in on position with extensions 26 and 28 of the ferromagnetic terminal elements 14 and 16. These extensions 26 and 28 may also be ridged to produce a wiping or wedging action for producing a good electrical contact even when the surfaces may become partially oxidized. The switch blade 17 is shown in phantom in the off position in FIGURE 1.

Inside the housing of the toggle lever assembly 12, recessed compartments 30 and 31 are provided for retaining the end portions 33 and 34 of the switch blade 17 and magnet 10 respectively. This assures that both elements are moved around pivot shaft 19 when the toggle lever is operated. The pivot shaft uses a bearing surface 38 within the toggle housing and a mating one (not shown) between the switch housing cover 40 and the box 42 to hold the toggle in operating position within the switch housing box 42. Thus the toggle 12 may display the index face 44 engraved ON in one stable position and the index face 46 engraved OFF in the other stable position.

As the magnet moves from one position to the other it is stopped by extensions 50 and 52 of the respective terminal elements 14 and 16. These extensions, being ferromagnetic serve to hold the magnet 10 in contact until forcibly removed by manual operation of toggle 12. The snap action hereinbefore described serves to cause the switch blade 17 to move quickly in and out of electrical contact so that arcing is minimized.

Terminal lugs 60 and 61 are provided for external wiring to the respective terminal elements 14 and 16. Rivets or screws 62-63 hold the elements in place within the box 42.

Because of the snap action, considerable striking force is exerted when the magnet 10 hits the rests 50 and 52. This not only results in a snapping noise but can serve to change the magnetic properties of some magnets by shock. Accordingly, a thin layer of acoustically absorbent material is used to cover the tip of magnet 10. This can be applied by dipping the tip of the magnet in a plastic material for example.

No particular precautions need be taken with the magnets, although they are preferably of the cast Alnico type and are large enough to prevent breaking about the shaft hole 73 when the snap action occurs. The Alnico retains its magnetism well when physically shocked. As shown in FIGURE 4 the magnets may be cast in multiple bar-shaped sections and broken apart so that they are quite inexpensive.

By mounting the magnet in the toggle, only one is required and the shape is kept simple to accomplish bistable positioning.

It is therefore evident in accordance with the invention that improvements have been made in the snap switch art as defined in the following claims.

I claim:

1. A switch having a toggle lever assembly pivotable about a pin and with only one permanent magnet mounted to move therewith, two ferromagnetic members positioned adjacent two extreme positions of movement of said magnet by said toggle lever assembly to hold the toggle lever assembly in either of two stable rest positions by magnetic attraction of said magnet to said members, contact bridging structure mounted to move with said toggle lever assembly and said permanent magnet and separate contact means integral with each of said two ferromagnetic members to form a closed conductive path with said bridging structure When said toggle lever assembly is in only one of said positions.

2. A switch as defined in claim 1 wherein the magnet is a bar magnet having one tip extended from said toggle assembly to engage said ferromagnetic members, and an acoustically absorbent coating on said tip to engage said members silently.

References Cited in the file of this patent UNITED STATES PATENTS Hubbell Sept. 5, 1950 Leslie Apr. 17, 1956 Maciszewski et a1. July 22, 1958 Mink Aug. 30, 1960

Claims (1)

1. A SWITCH HAVING A TOGGLE LEVER ASSEMBLY PIVOTABLE ABOUT A PIN AND WITH ONLY ONE PERMANENT MAGNET MOUNTED TO MOVE THEREWITH, TWO FERROMAGNETIC MEMBERS POSITIONED ADJACENT TWO EXTREME POSITIONS OF MOVEMENT OF SAID MAGNET BY SAID TOGGLE LEVER ASSEMBLY TO HOLD THE TOGGLE LEVER ASSEMBLY IN EITHER OF TWO STABLE REST POSITIONS BY MAGNETIC ATTRACTION OF SAID MAGNET TO SAID MEMBERS, CONTACT BRIDGING STRUCTURE MOUNTED TO MOVE WITH SAID TOGGLE LEVER ASSEMBLY AND SAID PERMANETN MAGNET AND SEPARATE CONTACT MEANS INTEGRAL WITH EACH OF SAID TWO FERROMAGNETIC MEMBERS TO FORM A CLOSED CONDUCTIVE PATH WITH SAID BRIDGING STRUCTURE WHEN SAID TOGGLE LEVER ASSEMBLY IS IN ONLY ONE OF SAID POSITIONS.

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