US 4,900,880 A · Gas damped crash sensor

Abstract

Conventional ball-in-tube, gas-damped, crash sensors utilize a gold plated ball to bridge two contacts. When the ball senses acceleration (deceleration) in the longitudinal direction of a cylinder of sufficient magnitude and duration, it moves to where it bridges the contacts, completing the electrical circuit and initiating deployment of a safety restraint system. The contact duration of this type of sensor is significantly affected by bouncing of the contacts after being hit by the sensing mass and by the accelerations in directions perpendicular to the axis of the tube. This sometimes results in no triggering, or late triggering, of the sensor. A switch activated by magnetic flux is combined with this type of gas-damped sensor to provide a solid and reliable contact duration and ensure the correct functioning of the sensor. The level of biasing force for crash zone crash sensors of this type has been increased to avoid late firing problems on marginal crashes.

Claims13

Dependent claims

A crash sensor comprising:

(a) a tubular passage;
(b) a magnetically permeable sensing mass, arranged to move in said passage between a first location and a second location;
(c) a magnet for biasing said sensing mass toward said first location in said passage;
(d) first and second electrical contacts arranged to come in contact with each other when said sensing mass is moved to said second location, both said first and said second contacts being constructed of magnetically permeable material;
(e) means for concentrating magnetic flux from said magnet through said first and second contacts in response to the presence of said sensing mass at said second lcoation, such that said contacts are mutually attracted to each other and tend to remain in contact once closed as long as said flux is present.

2 more elements

Dependencies are inferred from the claim text.

Gas damped crash sensor

Life of this patent

Gas damped crash sensor

Life of this patent

Abstract

Claims13