Crash sensing switch
First Claim
1. In a crash sensor for an occupant protection system of a vehicle of the type comprising a sealed gas filled tube having an axis, a sensing mass movable axially inside and in close proximity to said tube, said movement causing displacement of said gas and including means for viscously conducting said displaced gas,said sensing mass being movable during a crash from a normal resting position to a second position and there being sensing means for ascertaining when said sensing mass has moved to said second position, the improvement comprising:
- flow restricting means for limiting flow of said gas between said sensing mass and said tube, and whereinsaid means for viscously conducting comprises a duct for viscously conducting said gas past said flow restricting means.
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Accused Products
Abstract
A crash sensing switch for automotive vehicles has a cylindrical piston that moves sealingly in a tube during a crash to bridge a pair of contacts. Viscous flow of air through ducts creates pressures that resist movement of the piston. A venting valve may be incorporated in the piston to increase contact dwell. Impedance of the ducts may be adjusted during manufacture by blocking one or more of the ducts. The clearance between the piston and the tube limits air flow between the piston and the walls of the tube and provides aerodynamic lubrication between the piston and the tube during cross axis vibrations. A piston ring may assist in preventing air flow between the piston and the walls of the tube. There may be compensation for changes of air viscosity with temperature. One way to compensate is to make the contacts of thermostat metal which bends with temperature to change the distance the piston must move to bridge the contacts. Another way is to provide a valve incorporating thermostat metal which opens or closes certain ducts to compensate for changes of air viscosity with temperature. Compensation for variation of air viscosity with temperature may be provided at higher temperatures but not at lower temperatures. An injection molded cap includes connector pins to form an integral connector and hermetically seal the interior from the environment. Contact height setters may be incorporated into the cap to assure the desired piston movement for switch closure. Calibration may be done at manufacture by adjusting the piston movement required for switch closure. The combination of these elements provides a crash sensing switch having superior performance and costing much less than known crash sensing switches.
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Citations
77 Claims
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1. In a crash sensor for an occupant protection system of a vehicle of the type comprising a sealed gas filled tube having an axis, a sensing mass movable axially inside and in close proximity to said tube, said movement causing displacement of said gas and including means for viscously conducting said displaced gas,
said sensing mass being movable during a crash from a normal resting position to a second position and there being sensing means for ascertaining when said sensing mass has moved to said second position, the improvement comprising: -
flow restricting means for limiting flow of said gas between said sensing mass and said tube, and wherein said means for viscously conducting comprises a duct for viscously conducting said gas past said flow restricting means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. In a crash sensor for an occupant protection system of a vehicle of the type comprising a sensing mass movable during a crash from a normal resting position, the improvement comprising:
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sensing means comprising an electrical contact for ascertaining when said sensing mass has moved a predetermined distance from said normal resting position, and said electrical contact comprises thermostat metal thereby providing a predetermined change in said predetermined distance consequent to a predetermined change in temperature. - View Dependent Claims (14, 15)
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16. In a crash sensor for an occupant protection system of a vehicle of the type comprising a sensing mass movable in a tube and including an electrical contact and contact bridging means for contacting said electrical contact upon a predetermined movement of said sensing mass, the improvement comprising:
means for causing said contact bridging means to move axially relative to said sensing mass upon movement of said sensing mass beyond said predetermined movement.
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17. A crash sensor for an occupant protection system of a vehicle comprising:
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a gas filled tube having a tube axis, a sensing mass movable axially inside said tube and, there being a clearance between said sensing mass and said tube and said clearance being such that cross axis vibrations of a vehicle crash cause said gas to lubricate said movement of said sensing mass. - View Dependent Claims (18)
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19. In a crash sensor for an occupant protection system of a vehicle of the type comprising a sensing mass movable during a crash from a normal resting position and sensing means for ascertaining when said sensing mass has moved to a second position, the improvement comprising:
temperature compensation means for causing said second position to vary with temperature. - View Dependent Claims (20, 21)
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22. In a crash sensor for an occupant protection system of a vehicle of the type comprising a movable sensing mass wherein movement of said sensing mass causes viscous flow of displaced gas, the improvement comprising:
means utilizing variation of said viscosity with temperature for causing said switch to close more quickly in a crash at a low temperature than it would close in a crash having the same deceleration as a function of time at a nominal temperature that is higher than said low temperature. - View Dependent Claims (23)
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24. In a crash sensor for an occupant protection system of a vehicle of the type having an enclosure, sensing means disposed inside said enclosure and responsive to decelerations of a crash and having electricity conducting means connecting said sensing means with an element of said occupant protection system located outside said enclosure, the improvement comprising:
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said electricity conducting means having an extended segment insert molded into a plastic injection molding, said molding being located between said inside and said outside, and said segment being of sufficient length to prevent contaminant intrusion from said outside into said inside along said extended segment. - View Dependent Claims (25, 26, 27)
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28. In a crash sensor for an occupant protection system of a vehicle of the type comprising a sensing mass movable axially inside and in close proximity to a sealed, gas filled tube during a crash from a normal resting position and sensing means for ascertaining when said sensing mass has moved to a second position, the improvement comprising:
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flow restricting means for limiting flow of said gas between said sensing mass and said tube, a duct for viscously conducting said gas past said flow restricting means, temperature responsive valve means controlling flow through said duct, said valve means providing a nominal impedance to flow through said duct at a nominal temperature, and said valve means providing less than said nominal impedance at a second temperature that is higher than said nominal temperature. - View Dependent Claims (29, 30, 31, 32)
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33. In a crash sensor for an occupant protection system of a vehicle of the type having an interior containing contacts bridged upon sensing a crash and having electricity conducting means connecting said contacts with elements of said occupant protection system that are outside said crash sensing switch, the improvement comprising:
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said electricity conducting means being insert molded into a plastic injection molding, and said electricity conducting means having an extended segment inside said molding of sufficient length to prevent contaminant intrusion along said electricity conducting means. - View Dependent Claims (34, 35, 36, 37, 38)
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39. A crash sensor for an occupant protection system of a vehicle of the type comprising a sensing mass movable axially inside and in close proximity to a sealed, gas filled tube during a crash from a normal resting position, means for viscously conducting the gas displaced by movement of said sensing mass and sensing means for ascertaining when said sensing mass has moved a predetermined distance from said normal resting position, the improvement comprising:
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flow restricting means for limiting flow of said gas between said sensing mass and said tube, and wherein said means for viscously conducting is a duct for viscously conducting said gas past said flow restricting means. - View Dependent Claims (40, 41, 42, 43, 44, 45, 46, 47, 48, 49)
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50. In a crash sensor for an occupant protection system of a vehicle of the type comprising a sensing mass movable from a resting position in a tube and including electrical contacts and contact bridging means movable with said sensing mass for bridging said electrical contacts upon a predetermined movement of said sensing mass away from said resting position, the improvement comprising:
means for causing said contact bridging means to move axially relative to said sensing mass upon movement of said sensing mass beyond said predetermined movement.
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51. A crash sensor for an occupant protection system of a vehicle comprising:
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a guiding means having an axis, a sensing mass axially movable relative to said guiding means, said sensing mass being guided in axial movement by said guiding means with a clearance between said sensing mass and said guiding means, a gas occupying said clearance, said clearance being such that cross axis vibrations cause said gas to lubricate said movement of said sensing mass.
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52. A crash sensor for an occupant protection system of a vehicle comprising:
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a movable sensing mass, guiding means for guiding the movement of said sensing mass, a clearance between said sensing mass and said guiding means, and a gas occupying said clearance, said clearance being such that cross axis vibrations of a vehicle crash cause said gas to lubricate said movement of said sensing mass. - View Dependent Claims (53, 54)
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55. In a crash sensor for an occupant protection system of a vehicle of the type comprising a movable sensing mass, the movement of said sensing mass being affected by viscosity of a gas, the improvement comprising:
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means for utilizing variation of the viscosity of the gas with temperature to cause said switch to close more quickly in a crash at a low temperature than in the same crash at a nominal temperature that is greater than said low temperature, and means for compensating for variation of the viscosity of the gas with temperature at temperatures above said nominal temperature but not below said nominal temperature.
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56. In a crash sensor for an occupant protection system of a vehicle of the type comprising a sensing mass movable axially inside and in close proximity to a sealed, gas filled tube, means for viscously conducting the gas displaced by movement of said sensing mass, said sensing mass being movable during a crash from a normal resting position to a second position, and sensing means responsive to movement of said sensing mass to said second position, the improvement comprising:
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flow restricting means for limiting flow of said gas between said sensing mass and said tube, and said means for viscously conducting comprises a duct for viscously conducting said gas past said flow restricting means. - View Dependent Claims (57, 58, 59, 60, 61, 62, 63, 64, 65, 66)
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67. A crash sensor of the type comprising a sensing mass movable axially inside and in close proximity to a sealed, gas filled tube during a crash from a normal resting position to a second position, said movement causing displacement of said gas, and sensing means for ascertaining when said sensing mass has moved to said second position, the improvement comprising:
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flow restricting means for limiting flow of said gas between said sensing mass and said tube, and a duct for viscously conducting said gas past said flow restricting means.
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68. In a crash sensor for an occupant protection system of a vehicle of the type comprising a sensing mass movable during a crash from a normal resting position, the improvement comprising:
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sensing means for ascertaining when said sensing mass has moved a predetermined distance from said normal resting position, and temperature responsive means for varying said predetermined distance with temperature.
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69. A crash sensor for an occupant protection system of a vehicle, said sensor comprising a sensing mass movable axially inside a sealed gas filled tube during a crash from a normal resting position and sensing means for ascertaining when said sensing mass has moved a predetermined distance from said normal resting position, the improvement comprising:
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sealing means for impeding flow of said gas between said sensing mass and said tube, and duct means for viscously conducting said gas past said sealing means, said sealing means causing a preponderance of gas flow to be through said duct means rather than between said sensing mass and said tube. - View Dependent Claims (70)
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71. A crash sensor for an occupant protection system of a vehicle of the type comprising a member defining a passage, a sensing mass movable in said passage during a crash from a normal resting position and sensing means for ascertaining when said sensing mass has moved a predetermined distance from said normal resting position, the improvement comprising:
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said passage being filled with a gas, sealing means for limiting flow of said gas between said sensing mass and said member, and a duct for viscously conducting said gas past said sealing means.
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72. A device for use in a vehicle where it is subject to contact with potentially damaging elements, said device being of the type having an enclosure containing a component of an electronic circuit and having electricity conducting means for connecting said component with a second component located outside said enclosure, the improvement comprising:
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said electricity conducting means being insert molded into a plastic injection molding, and said electricity conducting means having an extended segment inside said molding of sufficient length to prevent intrusion of said potentially damaging elements along said extended segment. - View Dependent Claims (73, 74, 75, 76, 77)
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Specification