Abstract: A gas damped deceleration switch for a vehicle performs repeatedly in a consistent manner in response to decelerating crash forces acting transversely to the direction of movement of the vehicle or traversely to the axis of the deceleration switch. A mass assembly comprising a mass and a damping member is supported for movement along the axis of the deceleration switch in response to deceleration of the vehicle. A spiral spring is connected to the mass assembly at a location in a plane which extends perpendicular to the axis of the deceleration switch and which contains the center of mass of the mass assembly. Axially transverse components of a deceleration pulse experienced by the deceleration switch act upon the movable mass assembly at the axial location wherein the movable mass assembly is least susceptible to being moved out of its position centrally aligned with the axis of the deceleration switch.

Abstract: A temperature sensing transducer has a mechanically vibrating member whose rigidity varies with temperature, changing the resonant frequency. An output signal is generated having a frequency controlled by the vibrating member. The rigidity is caused to vary with temperature by making the vibrating member from a material whose modulus of elasticity is sensitive to temperature changes in the desired measurement range. Also by making the vibrating member of a bimetal shaped as a frusto-conical disk, the rigidity of the disk changes with temperature due to internal strains.

Abstract: An electric heater for heating diesel fuel includes a housing having an inlet and an outlet. A flat disk-shaped PTC thermistor is centrally mounted in the housing and is arranged so that the inlet directs fuel against one side of the thermistor to divert the flow of fuel outwardly around the marginal edges of the thermistor. An electrical resistance heater unit surrounds the thermistor between the walls of the housing and the thermistor and is provided with spaces through which the outwardly diverted fuel passes. A divider wall in the housing spaced from the heater unit and thermistor directs the fuel passing through the heater unit across the opposite side of the thermistor to the housing outlet. The PTC thermistor and electric heater unit are connected electrically in series whereby the thermistor functions to control heating output of the fuel heater in accordance with ambient temperature conditions.

Abstract: A glow plug control circuit uses two normally closed thermally actuated switches in series with a power relay and a timer switch across the battery when the ignition switch is turned on; the power relay connects the glow plugs to the battery. At least one of the two switches cycles on and off to limit the temperature of the glow plugs. Another normally closed thermally operated switch has a heating element in series with the glow plugs for turning off a lamp after the glow plugs are energized for a predetermined time. If one or more of the glow plugs are open-circuited, the lamp is cycled on and off with the cycling on and off of current through the glow plugs by the power relay, to signal a fault condition.

Abstract: A thermally operated snap-acting switch uses a switch arm and tension spring for rotating the switch arm. A thermal-responsive element moves the pivot of theswitch arm relative to the centerline of the spring to actuate the switch. Heater means activates the thermal-responsive element for operating the switch.

Abstract: A thermostatically controlled electric fuel heater for raising the temperature of diesel fuel flowing from a fuel tank to a fuel filter to prevent precipitation of wax crystals in the fuel filter and consequent filter clogging at low ambient temperatures includes a heat conductive tube incorporated as part of the fuel line a short distance upstream of the filter. An electric heating assembly is positioned on the tube and includes an electric resistance heating element helically wound about the tube and controlled by a thermostat responsive to the temperature of the tube and located upstream from the heating element. The thermostat includes a molded plastic frame having a central opening through which the tube passes. The thermostat includes a bimetallic thermal element secured to the frame and arranged to actuate a snap-action switch carried by the frame. The frame includes a baffle for thermally isolating the thermal element from the heating element.

Abstract: A diesel fuel filter in which wax crystals that tend to clog the filter at low ambient temperatures are directly heated to melt the crystals, allowing them to pass through the filter. A low energy heating element is positioned adjacent the filter element in the region where wax normally accumulates. The heater melts the wax without significantly raising the temperature of the fuel.

Abstract: A thermal device for controlling the temperature of glow plugs in a diesel engine in which current is applied to the glow plugs from the battery through a relay, the relay in turn being actuated by a thermally controlled switch controlled by a heater. The heater applies heat to the thermal-sensitive switch. The relay also controls current through the heater so that the heater cycles in unison with the glow plugs. The thermally-operated switch includes a bimetallic element which is heated by the heater. The bimetallic element is mounted in the engine block so as to be subject to the same ambient temperature conditions as the glow plugs. A thermal timer responsive to the same ambient temperature conditions includes a resistance heater element energized from the alternator. The thermal timer switch de-energizes the relay when heated to a predetermined temperature.

Abstract: A crash-sensing switch assembly for breaking an electrical circuit has a weight pivotally supported on a horizontal surface with the center of gravity above the surface. The weight is free to move away from the surface if the assembly is inverted. Movement of the weight away from the surface, either by tilting or falling, brings the weight into engagement with the trip lever of a latch, releasing a switch to break the circuit.

Abstract: A snap-action thermal relay in which a thin sheet of spring material having a central opening is mounted at one point along one edge and is crimped along an adjacent edge to distort the sheet into a slightly convex bowed shape. A heater element in the form of a thin band of metal is anchored at either end to the normally convex surface of the sheet adjacent opposite edges of the sheet, with a bridging member inserted between the band and the sheet to put the band under tension. A printed circuit heating element is applied to the band on the side opposite from the sheet. The tension in the band holds the sheet in a concave bowed condition. Heating of the bank reduces the tension in the band and allows the sheet to snap back to its normal convex bowed condition. This action brings the band into direct thermal contact with the convex surface of the sheet over a substantial length of the band to provide good conductive transfer of heat from the band and heater to the spring sheet.

Abstract: The air bag safety system is a self-contained, modular apparatus including: an inflatable bag, an inflating unit connected to the bag, and a sensor. The inflating unit provides gas for inflating the bag. The sensor is disposed adjacent to the apparatus and is responsive to a predetermined level of deceleration of a vehicle for activating the inflating unit. The system also includes a fail-safe interlock to prevent the sensor from activating the inflating unit when the system is not properly mounted or internal parts fail in service.

Abstract: The sensor includes a linearly movable mass including two sections and spring means urging one of the sections into operative engagement with means including an actuating element. The sensor also includes means releasably securing the two sections together and means releasing the securing means when the two sections have moved a predetermined distance against the urging of the spring. The two sections may be rollers of a rolamite unit. A flexible band extends around a portion of the two rollers. One example of a use for such a sensor is in an air bag safety restraint system.

Abstract: A mechanical sensor, operable without any source of electrical energy, includes: a rolamite means, a support means for the rolamite means, a trigger means, a hammer means, a primer means and a biasing means. The rolamite means is responsive to acceleration or deceleration above a predetermined amount and is mounted on the support means. The support means provides a path of movement for a portion of the rolamite means during deceleration. The trigger means is located adjacent to the support means and has a first portion and a second portion. The first portion of the trigger means extends into the path of movement for a portion of the rolamite means. The hammer means is located adjacent to the trigger means and is releasable by the trigger means. The primer means is activated by the hammer. The biasing means biases the hammer means toward the primer means.

Abstract: A thermally operated actuator useful as a relay, flasher, circuit breaker, or the like, in which a bimetal element is movable by heating and cooling in response to an electrical resistance heater and/or current passing through the bimetal element. In one form of the invention ambient compensation is achieved by rigidly clamping one end of the bimetal element to provide a cantilever support, and providing a support at the other end that either clamps or pivotally engages the bimetal element and longitudinally compresses the element, causing the element to buckle into a curved configuration. Heat is applied selectively to the bimetal element adjacent either end to produce a snap action change in the shape of the element between two fixed positions. In an alternative form of the invention, two parallel bimetal elements are linked together to provide ambient compensation while still providing the snap action change in shape in response to selectively applied heat.

Abstract: A sensor which utilizes the difference in thermal characteristic between two fluids to detect the presence of one fluid or the other. A continuously heated thermal expansion element activates a switch. When the element is brought in thermally conductive contact with a liquid, the heated element drops in temperature, shortening the length of the expansion element and activating the switch.