US3899649A

US3899649A - Inertial impact switch with normally centered, conductive oscillating contact

Info

Publication number: US3899649A
Application number: US481212A
Authority: US
Inventors: Bernard M Jenkins
Original assignee: CB Kaupp and Sons Inc
Current assignee: CB Kaupp and Sons Inc
Priority date: 1974-06-20
Filing date: 1974-06-20
Publication date: 1975-08-12
Anticipated expiration: 1992-08-12

Abstract

An inertial impact switch has a housing which comprises to coaxial sections both of which are conductive but are insulated from each other, and a movable contact member normally engaging one generally cylindrical section and spring held out of contact with the other section. The second-mentioned section is the second switch contact element and has a circular flange serving as one mounting terminal; and a second mounting terminal is electrically and coaxially mechanically connected to the firstmentioned section and has an approximately flat surface parallel with the housing axis, so that each of said circular flange and said flat surface of the second mounting terminal can be set on one conductor of a printed circuit on a board to connect the switch in a circuit and firmly mount the switch on the board.

Description

[ 91 [111 3,899,649 Aug. 12, 1975 [57] ABSTRACT An inertial impact switch has a housing which comprises to coaxial sections both of which are conductive Bernard M. Jenkins, Chatham, NJ. but are insulated from each other, and a movable I contact member normally engaging one generally cy- Asslgnee' i f; lindrical section and spring held out of contact with ap ewoo the other section. The second-mentioned section is the June 20,1974 second switch contact element and has a circular flange serving as one mounting tenninal; and a second [211 App! mounting terminal is electrically and coaxially mechanically connected to the first-mentioned section ZOO/61.51; 102/7042 R; 200/6L45 R and has an approximately flat surface parallel with the H01 35/ 14 housing axis, so that each of said circular flange and ZOO/61.45, 6l.53, 86 R, said flat surface of the second mounting terminal can 102/702 R be set on one conductor of a printed circuit on a board to connect the switch in a circuit and firmly References Cited mount the switch on the board. UNITED STATES PATENTS 2/l96l Kendall ......t....r.. ...m lO2/70.2 R X NORMALLY CENTERED, CONDUCTIVE OSCILLATING CONTACT Inventor:

Filed:

Field of Search............

United States Patent Jenkins INERTIAL IMPACT SWITCH WITH [52] US. CL...

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1 INERTIAL IMPACT SWITCH WITH NORMALLY CENTERED, CONDUC'I'IVE OSCILLATING CONTACT BACKGROUND OF THE INVENTION This invention relates to inertial impact switches of the normally open type wherein a first contact element is normally held by a spring in spaced relation to a second contact element and is brought into momentary closure contact therewith in response to an impact or shock received by the switch, for example, as shown by U.S. Pat. Nos. 2,983,800; 2,79l,653 and 3,649,787.

The present invention contemplates a switch wherein the first or movable contact element is enclosed within and insulated from a housing and the housing serves as the second contact element, and these contact elements are connected in electric circuits in different ways, frequently by wires each fixedly attached to one of the contact elements. Such wires make it difficult, and in many cases practically impossible to connect the wires to a printed circuit on a circuit board.

Also, the constructions of most of the prior art switches are too complicated and expensive.

SUMMARY OF THE INVENTION One object of the present invention is to provide a simple and relatively inexpensive inertial impaxt switch, and another object is to provide a novel and improved construction which eliminates wires or the like for connecting the switch in a circuit, and which can be easily and quickly connected in a printed circuit and firmly mounted on a circuit board.

The invention contemplates a housing comprising two coaxial sections both of which are conductive but are insulated from each other and one of which sections preferably is generally cylindrical and serves as a support for the movable contact element and has a coaxial annular terminal element while the other section constitutes the second contact element and the other terminal element; and the invention also includes a circular flange on the second-mentioned housing section coaxial with the housing and serving as a first mounting terminal to engage a part of a printed circuit, and a second coaxial mounting terminal on the first-mentioned housing section having at least one flat side surface which is adapted to set on another part of the printed circuit and hold the housing against rolling on the circuit board.

In the preferred form of the invention, said second coaxial mounting terminal has a plurality of flat side surfaces similar to a hexagonal nut.

A BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the invention, reference should be had to the following descriptions and accompanying drawings in which:

FIG. 1 is a top plan view of an impact switch constructed in accordance with the invention mounted on a printed circuit board;

FIG. 2 is a sectional view on the plane of the line 2-2 of FIG. 1 showing one end of the impact switch in elevation;

FIG. 3 is a similar view on the plane of the line 33 of FIG. I showing the other end of the impact switch in elevation;

FIG. 4 is a side elevational view of an impact switch mounted on the printed circuit board which is shown in section on the plane of the line 4-4 of FIG. 1;

FIG. 5 is a greatly enlarged central longitudinal sectional view through the impact switch, and

FIG. 6 is a horizontal sectional view on the plane of the line 66 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT Specifically describing the invention, the reference character A designates the inertial impact switch which is especially designed for use in connection with a printed circuit on a circuit board B.

The switch includes a housing which comprises two coaxial sections C and D both of which are electrically conductive but are insulated from each other and one of which, in the present instance section C serves as a support for a movable contact element 1 while the other section D constitutes a second contact element.

Preferably the section A is cup-shaped and has a bottom wall 2 and a cylindrical side wall 3 the outer end of which has a circumferential outwardly extending flange 4. The section D has a central dome-shaped portion 5 projecting from a body portion 6. An electrically insulating disc 7 is interposed between the body portion 6 and the flange 4 of the section C, and the body has an inturned edge portion 8 between which and the flange 4 is interposed another insulating disc 7a. The two housing sections are mechanically connected together in electrically insulated relation to each other.

The movable contact element which is shown as comprising a hollow cone having an outwardlyextending flange 10 at its open end seated on the bottom wall 2 of the housing section C, and a compression spring 11 is interposed between said flange I0 and the insulating disc 7 so as to normally hold the cone in approximately coaxial relation to the housing. The apex of the cone extends into the dome-shaped portion 5 of the housing section D and normally is in spaced relation thereto. The strength of the spring II and the normal distance between the apex of the conical movable contact element 1 and the portion 5 are such that when the switch is subjected to a sudden impact or shock, the movable contact element which will engage the dome portion 5 of the housing section D as indicated by dot and dash lines in FIG. 5 thereby to close a circuit between the two housing sections.

It will be understood by those skilled in the art that inertial impact switches of this character are commonly used in the art of fusing projectiles such as bombs, rockets, mortar shells and others; and it is necessary to provide two terminals on the switch for connecting the switch in an electrical circuit.

In accordance with the invention, the circular flange 8 coaxial with the housing provides one mounting terminal, while the other mounting terminal 9 is electrically and mechanically connected to the housing section C, preferably coaxially therewith and is formed with a surface I2 whose plane is approximately parallel to the axis x-x of the housing. Desirably, said surface is approximately flat and is spaced from said axis a distance approximately equal to the radius of said flange 8, and in tangential coincidence with the periphery of said flange as shown, for example, in FIGS. 2, 3 and 4. In its preferred form, the terminal 9 is polysided like a hexagonal nut, and has a central coaxial hole 13 which snugly receives the closed end portion of the housing section C, as best shown in FIGS. 5 and 6. It is desirable but not necessary that all sides be equidistantly spaced from the housing axis.

This construction is especially adaptable to connecting the switch in a printed circuit. in FIGS. 1, 2, 3 and 4 are shown portions of a printed circuit board E on which are printed circuit conductors E and G spaced apart a distance approximately equal to the spacing of the terminals 8 and 9 of the switch. The switch is connected in the circuit and at the same time is mounted on the board E. by placing one terminal 8 on one conductor F and placing the other terminal 9 on the conductor G, as best shown in FIG. 4. The flat side of the terminal 9 prevents rolling of the housing and ensures a stable setting of the impact switch on the board. The terminals are rigidly connected to the conductors by any suitable means, for example solder at the points indicated by reference characters and 16, respectively.

I claim:

1. An inertial impact switch comprising a housing which includes first and second coaxial conductive sections electrically insulated from each other, the first of which serves as a switch contact element, a coaxial movable contact element normally in conductive engagement with the second housing section, said movable contact element being normally urged by a spring into contact with the second housing section and into spaced relation to the first housing section and adapted to be urged to momentarily contact with the first housing section in response to an impact received by the switch, said spring having one end directly engaging said movable contact element and its other end abutting an insulation disc between said housing sections, said first housing section having an exterior circular mounting terminal and said second housing section having an exterior polysided mounting terminal coaxial with said circular mounting terminal.

2. An inertial impact switch as defined in claim I wherein said coaxial polysided mounting terminal is provided with at least one flat surface parallel to the axis of the housing.

3. An inertial impact switch as defined in claim 2 wherein said flat surface is spaced from the housing axis a distance approximately equal to the diameter of said circular mounting terminal in tangential coincidence with the periphery of said circular mounting terminal.

4. The inertial impact switch as defined in claim 1 wherein said second section is cup-shaped with a bottom wall and a cylindrical side wall, said movable element is conical and has an outwardly projecting flange at its larger end directly engaging said bottom wall of said second section, and said spring is helical and interposed between said flange on the movable contact element and said insulation disc.

Claims

2. An inertial impact switch as defined in claim 1 wherein said coaxial polysided mounting terminal is provided with at least one flat surface parallel to the axis of the housing.