Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS2475728 A
Publication typeGrant
Publication dateJul 12, 1949
Filing dateDec 31, 1946
Priority dateDec 31, 1946
Publication numberUS 2475728 A, US 2475728A, US-A-2475728, US2475728 A, US2475728A
InventorsSmith Walter M
Original AssigneeSmith Walter M
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Collision switch
US 2475728 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

July 12, mm. W. M. sMrrH COLLISION SWITCH Filed Dec. 51

I11 rel/tor Patented July 12, 1949 UNITED STATES PATENT OFFICE COLLISION SWITCH Walter M. Smith, San Diego, Calif.

Application December 31, 1946, Serial No. 719,576

(Cl. ZOO-52) 1 Claim.

This invention relates to improvements in electric switches for shutting off the motive power of a motor vehicle in case the latter collides with an object or another vehicle.

The primary object of the invention is to provide means for reducing the fire hazard resulting from the participation in a collision of a motor vehicle driven by an internal combustion engine which uses highly volatile or explosive fuels. The invention will also prevent or discourage hit and run driving after collisions.

Specifically, the invention contemplates provision of a safety switch adapted to automatically break the ignition circuit of the motor vehicle engine upon the occurrence of a collision, the switch being extremely simple in construction and highly efiicient in operation.

The exact nature of the present invention will become apparent from the following description and considered in connection with the accompanying drawing, in which:

Figure 1 is a bottom plan view of a collision switch constructed in accordance with the present invention.

Figure 2 is a central vertical sectional view of the switch shown in Figure 1, taken on the plane of line 22 of Figure 1.

Figure 3 is a horizontal section taken on line 3--3 of Figure 2.

Referring in detail to the drawing, the present switch includes a closure cap 5 having a lateral horizontal flange 6 which is apertured as at 1 to facilitate bolting of the switch to a motor vehicle. An inverted cup-shaped casing 8 has its lower end removably screwed or secured in the closure cap 5, and a central binding post 9 is fixedly secured to and extends through the top wall of casing 8. This binding post includes a screw Ill which extends through an aperture in the top wall of casing 8 and is drawn tight by a nut ll threaded thereon. A second nut I2 is threaded on the bolt I and coacts with the nut H for securing the terminal connection l3 of a conductor wire M to the binding post. A second central binding post I is fixedly secured to and extends through the closure cap 5, and this binding post I5 includes a bolt l6 passed through an aperture of the cap 5 and having an inner contact head i! formed at the top with a concave seat [8. A nut I9 is threaded on the bolt [6 to draw the same tight, and a. second nut 20 is threaded on said bolt l6 and coacts with the nut 19 to secure the terminal connection 2| of a second conductor 22 to said binding post I5. In practice, the wire 22 is connected to a terminal of the vehicle battery, and

the wire I4 is connected to the ignition coil so that the present switch is interposed or installed between the battery and the coil.

A solid metallic conducting ball 23 is arranged in the casing 8 and is adapted to rest in the seat M. A helical contact spring 24 is arranged in the casing 8 and is attached at its upper end to the binding post 9 so that the lower end of said spring is arranged to bear upon the ball 23 and thereby yieldingly hold the latter in the seat It. In this way, an electrical connection is normally provided between the binding posts 9 and I5 so as to close the ignition circuit until the ball 23 is jarred from between the contact head I! and the contact spring 24 by violent impact of the vehicle with an object or another vehicle. As soon as the latter occurs, the electrical connection between the binding posts 9 and i5 is broken so that the ignition circuit of the vehicle engine is opened for throwing the engine out of operation. As shown, a split washer 25 is placed on the bolt it within casing 8 and on the head of said bolt, and the upper end of spring 24 is extended through and above the washer 25 so that when the nut l i is tightened, the upper end of the spring 24 is securely attached to the binding post 9.

The present switch may be mounted on the vehicle so that it is diiiicult of access, thereby delaying resetting of the switch following a collision, which resetting requires removal of the casing 8 from the cap 5 and replacement of the ball 23 in the seat l8, as well as replacement of the casing 8 with respect to the cap 5. It will be apparent that the present switch prevents the electric current of the ignition system of the vehicle engine from igniting fuel which may splash or leak as a result of the collision.

The present switch is extremely simple in construction, economical to manufacture, and easy to install and use.

What I claim is:

A collision switch including a bottom closure cap having means to facilitate attachment thereof to a motor vehicle, an inverted cup-shaped casing having its lower end removably secured in said closure cap, a central binding post fixedly secured to and extending through the top wall of said casing, a second central binding post fixedly secured to and extending through the closure cap and having an inner contact head formed at the top with a concave seat, a conducting ball adapted to rest in said seat, and a helical contact spring in the casing attached at its upper end to the first named binding post and adapted to bear at its lower end upon said ball to yieldingly hold the latter in said seat and thereby provide an electrical connection between said binding posts until the ball is jarred from between the contact head and the contact spring by violent impact of the vehicle with an object or another vehicle, said conducting ball being of a diameter to pass into the space in the casing about the contact head of the second binding post and to rest on the closure cap entirely below the contact spring.


REFERENCES CITED The following references are of record in the file of this patent:

Number Number 4 UNITED STATES PATENTS Name Date Cole et al Sept. 13, 1932 Tucker et a1 Oct. 6, 1936 Williams et a1 Dec. 26, 1939 Brooks Nov. 18, 1941 FOREIGN PATENTS Country Date France Nov. 22, 1935

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1877557 *Dec 8, 1930Sep 13, 1932Delta Star Electric CoUnit type multistage auxiliary switch
US2056494 *Jun 8, 1934Oct 6, 1936Bruno HeinrichElectric switch
US2184868 *Mar 31, 1939Dec 26, 1939Lyndon A DurantBumper switch
US2262917 *May 4, 1940Nov 18, 1941Thomas BrooksAutomatic collision switch
FR790543A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2671832 *Mar 1, 1949Mar 9, 1954Graviner Manufacturing CoInertia or impact operated device
US2721237 *Aug 30, 1952Oct 18, 1955George YunkerJolt-actuated switch
US2835759 *Dec 2, 1955May 20, 1958Bendix Aviat CorpAccelerometer apparatus
US2894088 *Nov 10, 1955Jul 7, 1959Bendix Aviat CorpSwitch mechanism
US2912534 *Jan 17, 1958Nov 10, 1959C E VaughanCombined circuit breaker
US2921999 *Apr 1, 1957Jan 19, 1960Hughes Aircraft CoInertia switch
US3110780 *Aug 2, 1960Nov 12, 1963Gen Motors CorpSafety switch
US3141936 *Oct 17, 1962Jul 21, 1964Boyle John MConductive springs and ball acceleration switch
US3149606 *May 13, 1963Sep 22, 1964Hairlok Company LtdAccelerometers
US4237736 *Jul 19, 1979Dec 9, 1980Wright John HImpact gauge
US5543767 *Feb 2, 1995Aug 6, 1996Elenbaas; George H.Electrical switch
US6848389 *Aug 21, 2003Feb 1, 2005Gateway, Inc.Shock force indicating device
US8621673 *Mar 20, 2013Jan 7, 2014Antonio PietrantonioConcussion indicator
US20140288462 *Dec 3, 2013Sep 25, 2014Antonio PietrantonioConcussion Indicator
U.S. Classification200/61.45R, 116/203
International ClassificationH01H35/14
Cooperative ClassificationH01H35/14
European ClassificationH01H35/14