Abstract: A hydrostatic weight sensor comprises a bladder of flexible material that contains a fluid, preferably in an amount less than the capacity of the bladder when the bladder is unloaded, the pressure of which is sensed by a pressure sensor so as to provide a measure of weight upon the bladder. The bladder is mountable within a seat below the seat cushion and above the seat base, wherein seating loads are distributed across the bladder by the seat cushion and the seat base. In one embodiment, the bladder comprises a plurality of sheets of flexible material that are sealably connected to one another along a periphery, and are further connected to one another at one or more locations within the periphery so as to create a plurality of fluid containing zones that are in fluid communication with one another.

Abstract: A hydrostatic weight sensor comprises a bladder of flexible material that contains a fluid, preferably in an amount less than the capacity of the bladder when the bladder is unloaded, the pressure of which is sensed by a pressure sensor so as to provide a measure of weight upon the bladder. The bladder is mountable within a seat below the seat cushion and above the seat base, wherein seating loads are distributed across the bladder by the seat cushion and the seat base. In one embodiment, the bladder comprises a plurality of sheets of flexible material that are sealably connected to one another along a periphery, and are further connected to one another at one or more locations within the periphery so as to create a plurality of fluid containing zones that are in fluid communication with one another.

Abstract: A hydrostatic weight sensor comprises a bladder of flexible material that contains a fluid, preferably in an amount less than the capacity of the bladder when the bladder is unloaded, the pressure of which is sensed by a pressure sensor so as to provide a measure of weight upon the bladder. The bladder is mountable within a seat below the seat cushion and above the seat base, wherein seating loads are distributed across the bladder by the seat cushion and the seat base. In one embodiment, the bladder comprises a plurality of sheets of flexible material that are sealably connected to one another along a periphery, and are further connected to one another at one or more locations within the periphery so as to create a plurality of fluid containing zones that are in fluid communication with one another.

Abstract: A side impact crash is sensed from the motion of an edge wall of a vehicle door at a location distal to the door hinge in a direction of swing of the door. The rotation of the door about the hinge responsive to a side impact of the door magnifies the measured motion for a point of impact between the hinge and the sensing location. The motion may comprise acceleration, velocity or a relative motion such as relative velocity. The activation of safety restraint system is responsive to the sensed motion. In another embodiment, a side impact crash is sensed with a magnetic circuit comprising at least one coil and at least one permanent magnet, wherein an axis between the north and south poles of the magnet is substantially perpendicular to an axis about which at least one coil is wound. The relative motion is in a direction substantially perpendicular to the axis about which at least one coil is wound.

Abstract: A system 10 and method for performing diagnostic testing on a mechanical safing sensor used in vehicular safety restraint and vehicle crash discrimination systems includes an accelerometer 12 having an output 14 representative of acceleration, and a processor 20 having an first input 22 responsive to the accelerometer output 14 and a second input 24 responsive to a binary output 18 generated by a mechanical safing sensor 16. The system utilizes normally occurring deceleration events to reliably diagnose safing sensor malfunctions while requiring minimal additional hardware over conventional vehicle safety restraint systems.

Abstract: A hydrostatic weight sensor element incorporates a volume restorer for restoring the volume thereof when the applied load is removed therefrom, whereupon a check valve in fluid communication therewith admits sensing fluid thereinto if the pressure of the sensing fluid within the hydrostatic weight sensor element is less than local atmospheric pressure, so as to replenish lost sensing fluid. The volume restorer may comprise either the seat cushion, operatively coupled to the load bearing surfaces of the hydrostatic weight sensor element, or an elastic medium incorporated within the hydrostatic weight sensor element, whereby the volume restorer is adapted so that the restored volume of fluid is less than the volume capacity of the hydrostatic weight sensor element. A pressure relief valve is provided for releasing sensing fluid so as to prevent damage from overload conditions.

Abstract: In accordance with a preferred embodiment, a vehicle crash discrimination system (10) comprises a plurality of coil sensors (18) permanently mounted to a vehicle pillar, and a magnet 20 either mounted to a door (14) edge surface juxtaposed to the coils, or to the pillar if a suitable ferromagnetic flux collector is mounted on the door edge. The shape, size and spacing of the coils is predetermined to provide output signals in the coils responsive to the change in the magnetic field caused by movement of the door surface. The change in magnetic field is analyzed to indicate a vehicle crash.

Abstract: A seat weight sensor incorporates a fluid containing bladder placed in series with the load path in the seat, whereby a load applied to and distributed across the bladder increases the pressure of the fluid therein. The pressure of the fluid is measured by a pressure sensor and is substantially proportional to the magnitude of the applied load, and substantially inversely proportional to the supported area of the bladder. The output signal is substantially linear with respect to weight. Preferably, the amount of fluid in the bladder should be less than the capacity of the bladder when the bladder is unloaded. The seat weight sensor is incorporated into an occupant restraint system for controlling the safety restraint system responsive to the weight of the occupant.

Abstract: A hydrostatic weight sensor incorporates a bladder having a plurality of cells in fluid communication with one another, and with the outlet of a check valve, the inlet of which is in fluid communication with a source of sensing fluid, preferably the atmosphere. A cell-filling restoring mechanism is operatively coupled to a portion of the cells of the bladder. When the applied load is removed from the hydrostatic weight sensor, the volume of those cells operatively coupled to the cell-filling restoring mechanism is restored, whereupon if the pressure becomes less than the local atmospheric pressure, then fluid is added to the bladder through the check valve, thereby restoring lost sensing fluid. A pressure sensor operatively coupled to the bladder generates a signal responsive to the pressure of the sensing fluid within the bladder, and a signal processor calculates the weight of the occupant therefrom.

Abstract: The switch assembly comprises a single inertial sensing mass which is magnetically biased to an initial position along a path of travel within an enclosure. In this position, the mass holds a normally closed arming switch open. A normally open discriminating switch is disposed in the path of travel of the mass to be closed by the mass upon the occurrence of a velocity change indicating that a passive occupant restraint device such as an air bag should be deployed. Travel of the mass from the initial position releases the arming switch before the discriminating switch closes.

Abstract: An inertia switch comprises a mass which actuates an electrical switch assembly upon being subjected to a predetermined velocity change. The switch assembly comprises a set of two electrical contacts that are disposed within a switch enclosure in resiliently deflected, spaced apart conditions so as to make the set normally open when the inertia switch is in a quiescent condition. During the occurrence of such a predetermined velocity change, the mass operates an actuator of the electrical switch assembly to cause one contact to be further resiliently deflected and engage and also further resiliently deflect the other contact thereby creating switch closure indicating that the predetermined velocity change has occurred.

Abstract: Various embodiments of sensors are disclosed which contain an inertial mass that is magnetically biased to an initial position. In response to a certain deceleration, the mass is caused to swing about an axis and operate a switch. In some embodiments, the switch is one that is held open by the inertial mass' presence in its initial position and closes when the inertial mass swings away from its initial position, while in other embodiments it is one whose contacts are bridged by a conductive portion of the inertial mass only after the inertial mass has been displaced from its initial position, while in still other embodiments it is a reed switch that is magnetically operated. Motion of the inertial mass can be undampened or dampened. If dampening is desired, it can be accomplished either pneumatically or electromagnetically.