Abstract: An airbag deployment sensor has a cartridge containing a quantity of tape one end of which is attached to the inside surface of an airbag cushion. Deployment of the cushion pulls tape from the cartridge at a rate that is monitored by transmitting light through the tape, or by detecting the presence of metalized, or magnetic shielding portions, of the tape.

Abstract: A vehicle occupant position sensor is mounted on the front of an airbag which is deployed toward a vehicle occupant. The sensor comprises a capacitance sensor constructed by rendering portions of the airbag which face the vehicle occupant conductive. The airbag on which the sensor is placed is also constructed to allow venting of the airbag before it is fully deployed. The distance between the sensor and the vehicle occupant is continually determined with respect to the sensor. The output of the capacitive sensor is processed by a control system and is used to predict the interaction between the airbag and the vehicle passenger and to cause the airbag to be vented if that interaction is predicted to be more harmful than beneficial to the vehicle occupant. A system which prevents airbag venting once the airbag is inflated or nearly inflated can also be employed.

Abstract: An airbag deployment sensor stores a quantity of tape which is drawn out of a cartridge during airbag deployment by one end of the tape which is attached to the inside surface of an airbag. To facilitate assembly of an airbag system, the cartridge is designed with a key for locking the tape against premature extraction from the cartridge during the assembly process. The cartridge is used in combination with a mounting bracket which assures that the tape is free to be extracted from the cartridge once the cartridge is mounted to the bracket because, either the cartridge cannot be mounted to the bracket with the key in place, or the mounting bracket causes the key to move to a non-locking position.

Abstract: A crash detection system comprises two sensors with complementary performance characteristics, a controller evaluates the signals from both sensors to determine whether an airbag should be activated, when an airbag should be activated and whether multiple stages of the airbag should be activated. The first sensor preferably comprises a ball-in-tube sensor and the second sensor preferably comprises an electronic sensing module comprising an accelerometer and a CPU. The CPU receives signals from the accelerometer and the ball-in-tube sensor. The controller activates the airbag only if both sensors generate fire signals. The controller generates an airbag activation signal based upon crash type and the sum of the times required from the beginning of the crash for both sensors to generate fire signals.

Abstract: An acceleration-sensing mass/magnet is positioned about the center activation region of a reed switch. Motion of the acceleration-sensing magnet in either direction along the reed switch causes the reed switch to close. A first mechanism for sensing shock in a first direction is contained between a flange and a lid connected by a cylindrical wall. The flange and lid ride a plastic tube that contains the reed switch. The acceleration-sensing magnet travels between the flange and the lid on the tube. A second mechanism for sensing shock in a second opposed direction is formed by positioning a second mechanism about the magnet and the first mechanism. The second mechanism for sensing shock has a spring that biases the lid of the plastic sleeve against an abutment formed by a portion of a plastic capsule that encloses the entire shock sensor.

Abstract: An apparatus for detecting a force applied using a pressure sensor, an alternating voltage applied to the pressure sensor, and means for detecting the output voltage from the sensor to determine the force applied. One embodiment applies the alternating voltage using a DC input voltage and a microcontroller for switching the voltage applied to the sensor.

Abstract: A reed switch in a solid plastic body is positioned by a clip adjacent to a fluid container. A change in fluid level opposite the reed switch moves a magnet connected to a float, turning the reed switch on or off. Glass filled polyester is injected into a die which surrounds the reed switch supported on electrical plug blades. The reed switch has high stiffness leads positioned on the blades, and is oriented within the mold so the injected plastic flows along the glass tube of the reed switch, minimizing stresses on the reed switch, which could result in the reed switch becoming crack and/or broken. The molded plastic body incorporates an integrally formed clip arm that functions to position and hold the plastic body onto a larger structure. The magnet and float may move in a tube, may pivot, or slide along rails in response to a change in fluid level.

Abstract: A reed switch based shock sensor provides for passing electrical current through the coil spring used to bias the shock sensing magnetic mass. The spring is wrapped around the reed switch, allowing the coil spring to act as an electrical coil. The coil generates a magnetic field of sufficient strength to cause the reed switch reeds to attract and so close the reed switch, thus allowing the reed switch to be tested without the addition of a test coil.

Abstract: A metering device has a magnet with ten poles which is driven to rotate by a gear connected to a source of rotation that is proportional to fluid flow, the passage of time, or other phenomenon. A reed switch is mounted so that rotation of the poles of the magnet, into and out of a position adjacent to the reed switch causes the reed switch to open and close as the magnet rotates. The opening and closing of the reed switch causes a step change in voltage applied to an electronic device which increments a counter. A second reed switch spaced from the rotating magnet sufficiently so that it remains normally open can act as a sensitive device for detecting the presence of extraneous magnetic fields that might interfere with the operation of the first reed switch.

Abstract: A horn or other vehicle device can be activated or controlled by attenuating light. A horn switch, or an optical switch, has a light source, light detector, and a pathway for light extending through a void. The switches are activated by attenuating the light emitted by the light source. The light can be attenuated by at least partially obstructing the light or by modifying the orientation of either the light detector or the light source.

Abstract: Several force sensor assemblies are disposed within a vehicle seat to determine seat loading and assist in safety device activation. Each force sensor assembly has a sealed body filled with a liquid or a gel. A pressure transducer, together with a supporting integrated circuit, is positioned to respond to the pressure of the liquid or gel. Loads are applied to the pressure transducer through the gel by a piston riding within the body. Compressive loads are thereby transformed into a pressure on the sensor and its support electronics, resulting in a low cost, accurate, and durable sensor. The sensor functions well for relatively low loads of less than a few hundred pounds.

Abstract: A sensor of Giant magneto-resistive (GMR) type is attached to a seat belt anchor bracket. A seat belt passes through an opening in the bracket and is doubled back and sewn to form a loop. A magnet positioned on a sliding carriage is biased away from the sensor by springs. A seat belt loops around the carriage, and when tension is applied to the belt, the carriage with the magnet is drawn against the springs toward the GMR sensor. The GMR sensor measures the magnetic field present at the sensor and a microprocessor determines belt tension based on the known spring constants and the strength of measured magnetic field which is correlated with displacement of the magnet.

Abstract: A shunt is pivotally mounted to form a pendulum positioned between a reed switch and a magnet. The shunt is formed of ferromagnetic material and is mounted such that as long as it remains between the reed switch and the magnet the reed switch remains open. The shunt is held or biased between the magnet and the reed switch by the force of the magnetic attraction between the shunt and the magnet. The mass of the shunt acts as both a tilt sensor which responds to gravity and an accelerometer sensitive to crash-induced accelerations. The reed switch, magnet and shunt are mounted in a housing which positions the reed switch and magnet and controls the maximum range of motion of the pendulum-mounted shunt. An alternative embodiment employs a subassembly which includes a magnet, a shunt, and a selectively positioned mass, the subassembly is mounted to pivot over a reed switch. The magnet is positioned on or very near the pivot axis. The shunt is positioned further from the pivot axis toward the reed switch.

Abstract: A bidirectional shock sensor is constructed from a reed switch positioned between two shock sensing magnets. Each magnet is an annular ring which travels parallel to the reed switch reeds on a shaft spaced in a direction perpendicular to the axis of the reed switch. A spring pre-loads a first magnet against a first stop. A second spring pre-loads a second magnet against a second stop. The direction of travel of the first and second magnets is opposite and the first and second stops are positioned at opposite ends and on opposite sides of the reed switch. The magnets and the shafts on which they travel are positioned on identical housings which are arranged as mirror images with the reed switch positioned therebetween.

Abstract: A seat belt buckle incorporates a spring mounted on the latch. When the latch engages with the tongue of a seat belt, the tongue can move against the spring in response to tension loading of the seat belt while remaining securely latched. This motion due to belt tension is resisted by the spring, with a selected spring constant. A sensor is used to monitor the presence and position of the tongue either directly or by measuring motion of the latch. The position information, which is related to spring compression, is used to determine loading on the tongue and thus seat belt tension.