Velocity change sensor with double pole sensor

• US 5,123,499 A
• Filed: 03/01/1991
• Issued: 06/23/1992
• Est. Priority Date: 10/19/1989
• Status: Expired due to Fees

• Current Assignee: Breed Automotive Technology, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: Breed Automotive Technology, Inc. (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Thuen, Ted, Breed, Allen K., Grossi, Carl T.
• Primary Examiner(s): Marmor, Charles A.
• Assistant Examiner(s): FERRITER, KARIN L
• Application Number:
  US07/663,409
• Time in Patent Office: 480 Days
• Field of Search: 200/61.45 R, 200/61.45 M, 200/61.53, 180/282, 280/734, 280/735
• US Class Current: 180/282
• CPC Class Codes: G01P 15/135 by making use of contacts which are actuated by a movable inertial mass
• CPC Class Codes: H01H 2001/0005 Redundant contact pairs in one switch for safety reasons
• CPC Class Codes: H01H 35/14 Switches operated by change of acceleration, e.g. by shock or vibration, inertia switch wherein the liquid constitutes a contact of the switch H01H29/002

Abstract

An accelerometer for sensing velocity changes particularly suited for passenger restraint systems in a motor vehicle for the deployment of an air bag includes a housing with contact blades and a magnetically biased contacting element. The contacting element is arranged to move toward the contact blades when a deceleration exceeding a threshold level is sensed. The contact blades are spaced away from each other so that one is bent toward the other by the contacting element to form a direct electrical path, thereby deploying the restraint system.

Claims

1. An accelerometer for sensing velocity changes comprising:

a housing with a first end and a second end;

a sensing element movably disposed in said housing; and

biasing means for applying a biasing force on said sensing element;

first and second contact blades said first contact blade being provided with a an insulating coating to prevent an electrical path through said sensing element, said sensing element being arranged and constructed to move said first contact blade from a first position toward a second position away from said first position in response to a deceleration force exceeding said biasing force to contact said second contact blade with said second contact blade being initially stationary as said first contact blade is being displaced.

2. The accelerometer of claim 1 wherein said biasing means comprises a permanent magnet.

3. A passenger restraint system for a motor vehicle comprising:

a passenger restraint device disposed in a motor vehicle for protecting a passenger in a crash; and

an accelerometer for sensing a velocity change of said motor vehicle coupled to said passenger restraint device and comprising;

a cylindrical housing disposed in said motor vehicle;

a first pair of contact blades axially disposed in said housing; and

contact closing means arranged in said housing for making direct electrical contact between said contact blades when said motor vehicle decelerates at a level exceeding a threshold level by displacing one contact blade of said first pair toward the other contact blade while said other contact blade initially remains stationary until it is touched by said one contact blade, said one contact blade having an insulated coating for insulating said blades electrically from said contact closing means.

4. The passenger restraint system of claim 3 wherein said contact closing means comprises a contacting element movably disposed in said housing and magnetic biasing means for biasing said contacting element.

5. The passenger restraint system of claim 4 wherein said biasing means urges said contacting element toward a first position away from said contact blades.

6. The passenger restraint system of claim 5 wherein said housing is arranged in a housing position in which said contacting element is urged toward said contact blades when said motor vehicle is decelerated.

7. The passenger restraint system of claim 5 wherein said biasing means comprises a permanent magnet for applying a magnetic force on said contacting element.

8. The passenger restraint system of claim 7 wherein said biasing means further comprises a conductive sleeve disposed inside said housing for applying said magnetic force to said contacting element.

9. The passenger restraint system of claim 7 wherein said contacting element comprises a ball.

10. The passenger restraint system of claim 7 further comprising a second pair of blades spaced away from said first pair, said contacting element bending one blade of each pair toward the other blade to form two electrical paths.