Cantilevered acceleration switch responsive to acceleration parallel to plane of substrate upon which the switch is fabricated and methods
First Claim
1. A micro-miniature acceleration switch comprising:
- a substrate having a planar surface;
an inertial mass member ("IMM") fabricated upon said substrate and movable relative to said substrate from a first position to a second position when said switch is accelerated along at least one direction parallel to said planar surface of said substrate by acceleration of sufficient magnitude; and
electrical contacts fabricated upon said substrate, at least one of which is coupled to said IMM, for moving between closed and open positions when said IMM moves between said first position and said second position.
2 Assignments
0 Petitions
Accused Products
Abstract
A micro-miniature acceleration switch (e.g., 10) has a substrate (14) and an inertial mass member ("IMM"12) fabricated upon the substrate. The substrate (14) has a planar surface (16), and the IMM (12) is movable relative to the substrate from a first position to a second position when the switch (10) is accelerated along at least one direction parallel to the planar surface by acceleration of sufficient magnitude. Electrical contacts (e.g., 42) are fabricated upon the substrate (14) with at least one contact being coupled to the IMM (12). The contacts (42) move between closed and open positions when the IMM (12) moves between the first position and the second position. In one embodiment, an electrode (e.g., 62) provides 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 (10) may conveniently be adjusted by adjusting the electrostatic force applied by the electrode (62). The switch (10) is particularly useful as a safing switch in a system (140) for controlling an air bag or other vehicle occupant protection device.
10 Citations
41 Claims
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1. A micro-miniature acceleration switch comprising:
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a substrate having a planar surface; an inertial mass member ("IMM") fabricated upon said substrate and movable relative to said substrate from a first position to a second position when said switch is accelerated along at least one direction parallel to said planar surface of said substrate by acceleration of sufficient magnitude; and electrical contacts fabricated upon said substrate, at least one of which is coupled to said IMM, for moving between closed and open positions when said IMM moves between said first position and said second position. - View Dependent Claims (2, 3, 4, 5)
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6. A switch adjustably responsive to an acceleration force, said switch comprising:
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a substrate having a planar surface; an inertial mass member ("IMMI") movable relative to said substrate from a hold position to an actuated position, said IMM relatively moving when said switch is accelerated along at least one direction parallel to said planar surface of said substrate 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 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 force along said at least one direction that is insufficient to overcome force 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 force along said at least one direction that is sufficient to overcome said force tending to restrain said IMM, whereby the acceleration along said at least one direction 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 (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of making a micro-miniature acceleration switch, said method comprising:
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providing a substrate having a planar surface; fabricating an inertia mass member ("IMM") upon the substrate such that the IMM is movable between first and second positions along the substrate when the switch is accelerated along at least one direction parallel to the planar surface of the substrate by acceleration of sufficient magnitude; fabricating electrical contacts upon the substrate such that at least one electrical contact is coupled with the IMM, and at least one contact is adjacent to the IMM and coupled with the substrate, and such that the contacts are relatively movable between closed and open positions when the IMM moves between the first and second positions. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. 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; and a safing switch responsive to crash acceleration of said vehicle, said safing switch comprising; a substrate having a planar surface; an inertial mass member ("IMM") fabricated upon said substrate and movable relative to said substrate from a first position to a second position when said switch is accelerated along at least one direction parallel to said planar surface of said substrate by acceleration of sufficient magnitude; and electrical contacts fabricated upon said substrate, at least one of which is coupled to said IMM, for moving between closed and open positions when said IMM moves between said first position and second positions. - View Dependent Claims (38, 39, 40)
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41. A method of deploying an occupant protection 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") movable relative to a planar-extending substrate upon which the IMM is fabricated, said IMM moving in a plane parallel to the extent of said substrate in response to a predetermined crash acceleration applied to said control circuit in a direction parallel to the extent of said substrate and above a predetermined amount 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 protection apparatus when said electrical signal is being generated by said IMM.
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Specification