MOTOR VEHICLE PRESSURE ACTUATED DEFORMATION RESPONSIVE SWITCH WITH PISTON ACTUATOR AND VENT OPENING

• US 3,654,412 A
• Filed: 02/10/1971
• Issued: 04/04/1972
• Est. Priority Date: 02/10/1971
• Status: Expired due to Term

• Current Assignee: Hitoshi Sato, Takashi Haruna
• Original Assignee: Hitoshi Sato, Takashi Haruna
• Inventors: Haruna, Takashi, Sato, Hitoshi
• Primary Examiner(s): Schaefer, Robert K.
• Assistant Examiner(s): Vanderhye, Robert A.
• Application Number:
  US05/122,881
• Time in Patent Office: 419 Days
• Field of Search: 180/91,94,96 200/832,81H,61.08,61.53,82D,DIG.10 340/61 116/32
• US Class Current: 200/83.00Z
• CPC Class Codes: H01H 35/34 actuated by diaphragm
• CPC Class Codes: Y10S 200/10 Curb, bumper and fender

Abstract

A trigger switch mechanism adapted to actuate motor vehicle safety devices in response to deformation of a particular portion of the vehicle body resulting from a collision of the motor vehicle with an obstruction. The mechanism comprises a cylinder mounted inside the particular portion of the vehicle body. A slidable piston is mounted within the cylinder and has a rod integrally formed therein. The rod extends axially from the piston and terminates at a suitable distance from the particular portion of the vehicle body. Deformation of the particular portion of the vehicle body exerts a force on the piston tending to move it in one direction. A shear pin is provided in the cylinder to prevent such piston movement until the force exceeds a predetermined magnitude. A pressure-sensitive switch is provided to close a circuit leading to the safety devices when the pressure within the cylinder chamber exceeds a predetermined level caused by the movement of the piston. A vent opening is provided in the cylinder so that the pressure within the same cannot exceed the predetermined level in the event of only a slight collision. The piston has another rod extending axially from the piston in the other direction. When the displacement of the piston exceeds a predetermined magnitude, the rod acts directly on the pressure-sensitive switch to close it.

Claims

1. A trigger switch mechanism adapted to actuate motor vehicle safety devices in response to deformation of a particular portion of the vehicle body, said mechanism comprising a cylinder having a cylinder chamber therein, a slidable piston mounted within said cylinder chamber and having a rod integrally formed therein, said rod being positioned relative to said particular portion of the vehicle body such that deformation of said particular portion of the vehicle body exerts a force on said piston and causes it to move axially in one direction, means for holding said piston in a position within said cylinder chamber until said force exceeds a predetermined value, a pressure-sensitive switch provided to close a circuit leading to said safety devices when the pressure within said cylinder chamber exceeds a predetermined level because of the movement of said piston in said one direction, and a vent opening provided in said cylinder, said vent opening being of such a size that only when the velocity of displacement of said piston exceeds a predetermined value the pressure within said cylinder chamber will rise to said predetermined level due to resistance given by escaping air by said sized vent opening.

2. A trigger switch mechanism according to claim 1, in which said piston has another rod integrally formed so as to extend axially in said one direction, said rod or plunger being capable of acting directly on said pressure-sensitive switch to actuate it when the displacement of said piston exceeds a predetermined magnitude.

3. A trigger switch mechanism according to claim 1, in which said cylinder is made up of a first cylindrical member having telescoped into a second cylindrical member for the sake of ease of assembly and installation.

4. A trigger switch mechanism according to claim 1, in which said plunger extends axially from one end of said piston and terminates at a suitable distance from said particular portion of the vehicle body.

5. A trigger switch mechanism according to claim 1, in which said means comprises a shear pin provided in said cylinder to prevent movement of said piston with respect to said cylinder, the mechanical strength of said shear pin being such that if said force exceeds a predetermined value said shear pin is cut permitting movement of said piston.

6. A trigger switch mechanism according to claim 1, in which said pressure-sensitive switch comprises an inlet port leading to said cylinder chamber, a sensor such as a plate-like diaphragm biased toward said inlet port in such a manner as to tightly seal it off, and a pair of contacts which are brought into contact with each other when said spring is caused to bend away from said inlet port due to a rise in the pressure within said cylinder chamber.