Abstract: This invention includes crash sensors designed to be used for frontal impact sensing and the strategies of using these sensors. It is analyzed and shown that velocity sensing or damped sensors are desirable for frontal impact sensing. Inertially damped sensors, with a damping force proportional to the square to velocity, is most appropriate. Such sensors can be made of plastic and in the shape of short round or rectangular cylinders. The particular shape the these sensors minimizes the chance that the sensors will be rotated during the crash. It is further concluded that these sensors should be installed on the frontal radiator structure or at such similar location near the front of the vehicle. A typical crash sensor includes a hinged plastic mass attached to the housing. The mass activates a contact assembly after a predetermined movement of the mass. The gap existing between the movable mass and the interior wall of the housing enhances the damping function of the crash sensor.

Abstract: This invention includes crash sensors designed to be used for frontal impact sensing and the strategies of using these sensors. It is analyzed and shown that velocity sensing or damped sernsors are desirable for frontal impact passenger compartment sensing. inertially damped sensors, with a damping force proportional to the square of velocity, is preferred for some applications. In other cases a viscous damped sensor is appropriate and in a few cases an undamped spring mass sensor will suffice. Such sensors can be made of plastic and in the shape of short housings. A preferred embodiment of this invention utilizes a swinging mass hinged to a housing as the sensing mass. Different geometries of the mass and the housing are disclosed and used to improve the performance of such sensors. These flapper mass sensors are useful for sensing frontal impacts in the passenger compartment both as primary sensors and as single or dual contact arming sensors.

Abstract: A crash sensor for a passive motor vehicle occupant restraint system, such as an inflatable air bag or seat belt tensioner. The crash sensor comprises a tubular passageway having a central, longitudinal axis; a sensing mass arranged to move within the passageway in the direction of the longitudinal axis between a first location and a second location; a device for biasing the sensing mass toward the first location in the passageway; and a device for closing an electrical circuit when the sensing mass moves to the second location in the passageway.The invention provides methods for reducing the motion of the sensing mass and the tubular passageway in a direction perpendicular to the longitude, and/or methods for reducing the angular momentum of the sensing mass, during motion of the sensing mass in the longitudinal direction.