US 3248504 A
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Description (OCR text may contain errors)
April 26, 1966 R. McGlRR ETAL CONNECTING SWITCH Filed Oct. 8, 1962 NNm I r////// r/ I g m m m a w FIG. 2
INVENTORS ROBERT MGIRR BY BENJAMIN A. GAY
United States Patent The present invention relates to an improved electrical I switch and more particularly to an electrical switch which connects electrical contacts. The switches of the present invention are especially suited to be actuated by an explosive charge.
Some types of projectiles and missiles require reliable, compact electrical switches which are stable to large multidirectional forces and which are operable while exposed to such forces, for example, when the projectile or missile containing the switches are in a state of violent tumbling or rolling.
The present invention provides an electrical switch that operates in a positive manner to make an electrical connection by connecting electrical contacts one with another and is independent of the position of the switch or forces acting upon the switch.
In general, the switches of the present invention comprise a slide member moveable along a line and a pair of spaced electrical contact members. The spaced contact members are generally positioned parallel to the line along which the slide member moves. At least one of 'the contact members has a free end extending toward the slide member arranged to contact the other contact member upon lateral pressure near the free end. The slide member is provided with a surface oblique to the direction of travel of the slide member. This surface is so oriented with the contact members that upon motion of the slide member toward and against one of the contact members having a free end, one contact member is pushed into contact with the other contact member. Preferably at least one of the electrical contact members is of a metal deformable into apermanent set. A driving means may also be provided to drive the slide member toward the contact members with sufiicient force to deform the deformable contact members into a position wherein there is physical contact between the contact members.
If desired, the contacting surface on the slide member.
Preferably, the terminal end of .at least one of the contact members has a layer of solder thereon'positioned so that the action of the slide member forcing the electrical contact members together provides a soldered electrical connection between the contact members.
Although the driving means may comprise a compressed spring released by either a mechanical or electrically actuated release mechanism, it preferably comprises an explosive charge fired by electrical energy. A particularly suitable driving means is an electrically actuated squib.
3,24 ,504 Patented Apr. 26, 1966 ice members are positioned in an enclosed space, the gas surrounding the electrical contact members undergoes compression by the movement of the slide member and a backpressure is formed which tends to dislodge the slide member from contact with the electrical contact members. Therefore, .in a preferred embodiment of the invention the slide member is comprised of separable sections, with the section closest to the contact members perforation allows the backpressure to bypass the portion of the slide member contacting the contact members and act upon a section of the slide member having no cavity therethrough. If the solid portion of the slide member is displaced, the displacement has no effect upon the portion in contact with the electrical contact members.
The invention will be better understood from the following description when considered in connection with the accompanying drawings.
FIGURE 1 is a longitudinal cross-sectional view of a switch in accord with the present invention.
FIGURE 2 is a longitudinal cross-sectional view of a modification of the switch shown in FIGURE 1 wherein the piston member comprises two sections.
In each of the views like components bear like numbers and for the most part, the switch in FIGURE 1 and the modification in FIGURE 2 may be discussed together.
A generally cylindrical metallic outer shell member 11 is sealed on one end by a plug of non-conducting material 13 and on the other end by a second plug of nonconducting material 15. The plug members may suitably be fabricated of such non-conducting material, as plastic, asphalt, rubber or glass. Preferably the plug members are fabricated of a ceramic material. A pair of spaced electrical contact members, 17 and 17' enter shell 11 through plug 13 and terminate within the shell. The electrical contact members 17 and 17' preferably are of a metal deformable into a permanent set, for example,
copper or brass. The free ends 19'and 19' of contacts 17 and 17' are coated with a thin layer of a solder 21, of metal or metallic alloy such as gold, lead, tin, silver amalgam, lead-tin or indium alloys. A slide member 23 having a cavity 25 is positioned in shell 11 in spaced relation to electrical contact members 17 and 17'. Cavity 25 is aligned with contact members 17 and 17. Cavity 25 is of sufiicient size to freely receive contact members 17 and 17'. Wall 27 of cavity 25 tapers to a narrowed opening 29. Narrowed opening 29 is of a size such that free ends 19 and 19' are tightly squeezed together upon insertion therein. Slide member 23 is preferably fabricated of a non-conducting material, for example, resin, hard rubber, compacted fiber board, or ceramic materials.
In FIGURE 2, a modification of the piston arrangement is shown wherein the piston has a first piston section 31 and a second piston section 32. The first piston section 31 is similar to piston member 23 shown in FIGURE 1 except cavity 25 extends completely therethrough to provide a means of equalizing pressure on either side of piston section 31. The second piston section 32 has no perforation therein and represents a solid obstruction across shell 11. Although the second or solid slide member section 32 is preferably fabricated of a non-conducting resin, it may be suitably fabricated of metal or other conductive material suitable to prevent the communication from one end of shell 11 to the other.
The'switches shown in the drawings both utilize a gas-forming explosive charge 33, suitably composed of lead mononitroresorcinate, positioned in proximity to the slide member. A firing means comprising leg wires 35 and 35' enters shell 11 through plug 15 and is electrically connected to a high resistance bridge wire 37 embedded in charge 33.
In operation, the gas-forming explosive charge is fired by applying sufiicient electrical energy to the bridge wire 37 via leg wires 35 and 35 to fire charge 33. The gases from charge 33 forceably move the slide member toward contact members 17 and 17. The tapered wall surface 27 of the slide member causes contact members 17 and 17' to be bent inward and into physical contact by lateral pressure on said contact members. The free ends 19 and 19' of the electrical contact members are coated with a thin layer of solder 21 and when forceably joined form a soldered connection. The free ends 19 and 19' of electrical contact members may be angularly cut to present a meeting face with tapered wall 27 of the slide member.
Although after firing the connection of electrical contact members 17 and 17' is completed, it is often desirable to protect the connection by maintaining wall 27 of the slide member in tight contact with the connected electrical contact members. The modification in FIGURE 2 shows a means of providing such contact. The gas in area 39 around electrical contact members 17 and 17' is compressed by movement of the slide member toward contact members 17 and 17'. This movement forms a backpressure in area 39 tending to force wall 27 of the slide member out of contact with the connected contact members. The modification shown in FIGURE 2 prevents this action by extending cavity 25 completely through the first section of slide member 31 to form a gas passage. The backpressure thereby bypasses the first section of slide member 31 by passing through extended cavity 25 and acts to force the second section of the slide member 32 toward plug 15 which does not affect the contact between wall 27 and connected electrical contact members 17 and 17.
It is obvious that modifications and alterations of the present invention will occur to one skilled in the art, and it is understood that changes can be made within the scope of the appended claims.
What is claimed is:
1. A switch for making an electrical connection comprising a sealed outer shell containing,
4 a pair of spaced electrical contact members having free ends extending generally in the same direction and made of a metal deformable into a permanent set,
a slide member having a contacting surface and moveable in said shell toward said free ends in a direction generally opposite to that in which said contact members extend,
said contacting surface providing a means so oriented with respect to said electrical contact members that on movement of said slide member toward and against said free ends, said free ends are deformed by lateral pressure into contact with one another, and
a squib means in said casing to drive said slide member toward said contact members with sufficient force to deform said deformable metal into a position wherein there is physical contact between said contact members,
said slide member comprising separate parts separately slidable in said shell, one adjacent to the squib means, being an imperforate piston member and another, comprising the said contacting surface, providing a gas passage between said piston and the locus of said electrical contacts.
2. A switch in accordance with claim 1 in which said contacting surface is obliquely inclined toward said electrical contact members.
3. A switch in accordance with claim 2 in which said surface comprises. a side wall of a cavity in said slide member, the space between opposite surfaces of said cavity narrowing within said slide member from a size suflicient freely to admit said spaced contact members to a size such that said free ends of such contact members are tightly squeezed together upon insertion therein.
4. A switch in accordance with claim 3 in which at least one free end of said pair of contact members is provided with a layer of solder.
References Cited by the Examiner UNITED STATES PATENTS 2,141,098 12/1938 Wahlstrom 339-276 2,558,188 6/1951 McWilliams 2O0l53 2,816,196 12/1957 Daudelin 20()-142 2,931,874 4/1960 Leaman 200-82 FOREIGN PATENTS 921,463 1/1947 France. 826,891 1/ 1960 Great Britain.
BERNARD A. GILHEANY, Primary Examiner.