Acceleration switch
First Claim
1. A switch adjustably responsive to an acceleration force, said switch comprising:
- an inertial mass member ("IMM") relatively movable from a hold position to an actuated position, said member relatively moving when said switch is accelerated and being deflectable out of its hold position in response to said switch acceleration of sufficient magnitude,electrical contacts, at least one of which is coupled to said IMM, for moving between closed and open positions when said IMM moves between said hold position and said actuated position,hold means comprising at least one hold electrode to which a hold voltage may be applied for adjustably establishing an electrostatic field creating a restraining force urging the IMM into its hold position, said field and said restraining force having a magnitude functionally related to said hold voltage, andmeans for applying a hold voltage to said hold electrode, andwherein said IMM remains in said hold position when said switch is subjected to acceleration forces that are insufficient to overcome forces tending to restrain said IMM to said hold position, including the restraining force established by said electrostatic field, and deflects to said actuated position when said switch is subjected to acceleration forces that are sufficient to overcome said forces tending to restrain said IMM,whereby the acceleration required to move relatively said IMM from said hold position to said actuated position may be adjusted by selecting the hold voltage applied to said hold means.
2 Assignments
0 Petitions
Accused Products
Abstract
An acceleration sensitive switch (10) equipped with an inertial mass member ("IMM") (12) that is deflectable from a holding position to an actuated position in response to a predetermined acceleration force. A voltage controlled hold plate (18) generates an electrostatic force that opposes the acceleration forces and holds the IMM (12) in a holding position until overcome by the predetermined acceleration force. The predetermined acceleration force necessary to trigger the switch may conveniently be adjusted by adjusting the voltage applied to the hold plate (18). The switch includes a self-test plate (34) that tests proper functioning of the switch. Other features include the interchangeability of the self-test plate and the hold plate. The switch is particularly useful as a safing switch in a system for controlling an air bag or other vehicle occupant restraint system.
46 Citations
65 Claims
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1. A switch adjustably responsive to an acceleration force, said switch comprising:
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an inertial mass member ("IMM") relatively movable from a hold position to an actuated position, said member relatively moving when said switch is accelerated and being deflectable out of its hold position in response to said switch acceleration of sufficient magnitude, electrical contacts, at least one of which is coupled to said IMM, for moving between closed and open positions when said IMM moves between said hold position and said actuated position, hold means comprising at least one hold electrode to which a hold voltage may be applied for adjustably establishing an electrostatic field creating a restraining force urging the IMM into its hold position, said field and said restraining force having a magnitude functionally related to said hold voltage, and means for applying a hold voltage to said hold electrode, and wherein said IMM remains in said hold position when said switch is subjected to acceleration forces that are insufficient to overcome forces tending to restrain said IMM to said hold position, including the restraining force established by said electrostatic field, and deflects to said actuated position when said switch is subjected to acceleration forces that are sufficient to overcome said forces tending to restrain said IMM, whereby the acceleration required to move relatively said IMM from said hold position to said actuated position may be adjusted by selecting the hold voltage applied to said hold means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A system for recognizing the onset of a crash of a vehicle and providing a control signal indicative thereof, comprising:
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an accelerometer responsive to crash acceleration of said vehicle for providing a crash acceleration signal which varies as a continuous function of said crash acceleration; microprocessor means responsive to the crash acceleration signal for determining from said signal whether said vehicle is experiencing a crash condition; a safing switch responsive to crash acceleration of said vehicle, said safing switch comprising an inertial mass member ("IMM") supported by a tensile force and relatively movable from a hold position to an actuated position in response to acceleration of said vehicle, electrical contact means associated with said IMM for generating an electrical signal when said IMM is in its actuated position, hold means responsive to a voltage for applying an electrostatic force to said IMM to bias said IMM into said hold position, and means for applying a voltage to said hold means to thereby establish the magnitude of the bias on said IMM and thus the predetermined vehicle crash acceleration necessary to force said IMM from its hold position to its actuated position; and means responsive to said microprocessor means and to said electrical signal provided by said electrical contact means for providing said control signal in accordance therewith. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
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51. A method of deploying occupant crash restraint apparatus in a vehicle as a function of the crash acceleration experienced by said vehicle comprising the steps of:
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providing a control circuit for assessing changes in the acceleration experienced by said vehicle, said control circuit including a safing switch having an inertial mass member ("IMM") that relatively moves in response to a predetermined crash acceleration level to generate an electrical signal indicating a crash event; applying an electrostatic force to said IMM to urge said IMM in the direction opposite the direction of acceleration movement of said safing switch, said applied electrostatic force being selected according to the predetermined level of acceleration to which said switch is to be responsive; generating an electrical signal when said IMM moves in response to acceleration of said switch greater than said predetermined crash acceleration level; and actuating said occupant crash restraint apparatus when said electrical signal is being generated by said IMM.
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52. In a crash detection apparatus capable of deploying an occupant air bag restraint, a safing switch responsive to a predetermined acceleration force and generating an electrical signal when said safing switch is actuated, said safing switch comprising:
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an inertial mass member ("IMM") relatively movable from a hold position to an actuated position in response to each acceleration of said switch; electrical contact means associated with the inertial mass member for generating an electrical signal when said IMM is in its actuated position; and hold means for generating an electrostatic attractive force urging the IMM into its hold position and restraining the IMM from relatively moving in response to a crash acceleration less than a predetermined crash acceleration value; whereby said IMM is relatively moved to its actuated position in response to a crash acceleration which overcomes the restraining action of the electrostatic force, and, when said IMM is in its actuated position, the electrical contacts means generates the electrical signal so as to enable the deployment of said air bag. - View Dependent Claims (53, 54, 55, 56, 57, 58, 59, 60, 61)
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62. An acceleration responsive switch comprising:
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a base member; a switch arm; mounting means for mounting said switch arm to said base member so that acceleration of said base member results in relative movement between said switch arm and said base member; a pair of electrical contacts, one of said electrical contacts mounted to said switch arm and a second of said electrical contacts mounted to said base member so that said acceleration of said base member changes the switching state of said pair of electrical contacts; and electrostatic bias means operatively coupled to between said base member and said switch arm for providing a bias force to resists relative movement between said switch arm and said base member. - View Dependent Claims (63, 64)
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65. A system for recognizing the onset of a crash of a vehicle and providing a control signal indicative thereof, comprising:
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an accelerometer responsive to crash acceleration of said vehicle for providing a crash acceleration signal which varies as a continuous function of said crash acceleration; microprocessor means responsive to the crash acceleration signal for determining from said signal whether said vehicle is experiencing a crash condition; a safing switch responsive to crash acceleration of said vehicle, said safing switch comprising a base member; a switch arm; mounting means for mounting said switch arm to said base member so that acceleration of said base member results in relative movement between said switch arm and said base member; a pair of electrical contacts, one of said electrical contacts mounted to said switch arm and a second of said electrical contacts mounted to said base member so that said acceleration of said base member changes the switching state of said pair of electrical contacts; and electrostatic bias means operatively coupled to between said based member and said switch arm for providing a bias force to resists relative movement between said switch arm and said base member; and means responsive to said microprocessor means and to said change of the switching state of said pair of electrical contacts for providing said control signal in response thereto.
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Specification