Occupant weight sensor for vehiclular seats, method for making and system therefor
First Claim
1. An occupant weight sensor particularly adapted for vehicular seats wherein the vehicular seats are supported on the chassis by a seat mechanism and the sensor is interposed between the chassis and the seat mechanism comprising:
- a sense element having a first body with a generally planar sense surface and having an outer periphery and a longitudinal axis, a post extending outwardly from the first body along the longitudinal axis for attachment to one of the chassis and the seat mechanism, a second body formed with a force transfer portion permanently attached to the sense element along the outer periphery thereof and having a mounting portion for attachment to the other of the chassis and the seat mechanism so that the sensor is disposed intermediate to the chassis and the seat mechanism, a full Wheatstone bridge having piezoresistors attached to the generally flat sense surface and having a bridge output, conditioning electronics supported on one of the first and second bodies electrically connected to the bridge for conditioning the bridge output signal, and a connector for providing electrical power for the bridge and for providing an electrical output.
4 Assignments
0 Petitions
Accused Products
Abstract
An occupant weight sensor (1) for placement between a frame (7) fixed to the chassis of a vehicle and a second frame (8) supporting a vehicle seat has a sense element having a first body (12, 22, 28, 34, 50, 62, 64, 68) formed with a planar sense surface on which are mounted piezoresistors electrically connected in a Wheatstone bridge configuration. A post (12a, 22c, 28c, 34e, 50b, 62a, 64a, 68b) extends outwardly from the first body for attachment to the first frame. A second body is formed with a force transfer portion (14a, 24g, 30d, 36b, 52a, 70a) permanently attached to the first body along an outer periphery circumscribing the sense surface. The piezoresistors are electrically connected to conditioning electronics received in a chamber formed between the two bodies. The effects of parasitic loads on the sense element are minimized by selected placement of the piezoresistors on the sense surface. Several variations are disclosed for attaching the sensor to the first and second frames and both longitudinally and laterally extending electrical connectors are shown.
24 Citations
21 Claims
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1. An occupant weight sensor particularly adapted for vehicular seats wherein the vehicular seats are supported on the chassis by a seat mechanism and the sensor is interposed between the chassis and the seat mechanism comprising:
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a sense element having a first body with a generally planar sense surface and having an outer periphery and a longitudinal axis, a post extending outwardly from the first body along the longitudinal axis for attachment to one of the chassis and the seat mechanism, a second body formed with a force transfer portion permanently attached to the sense element along the outer periphery thereof and having a mounting portion for attachment to the other of the chassis and the seat mechanism so that the sensor is disposed intermediate to the chassis and the seat mechanism, a full Wheatstone bridge having piezoresistors attached to the generally flat sense surface and having a bridge output, conditioning electronics supported on one of the first and second bodies electrically connected to the bridge for conditioning the bridge output signal, and a connector for providing electrical power for the bridge and for providing an electrical output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A strain gauge sense element comprising:
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a first generally cylindrical body having a first longitudinal axis and a portion formed with a circular generally planar sense surface lying in a plane generally perpendicular to the first longitudinal axis, the body having an outer periphery circumscribing the sense surface, a first post extending outwardly from the body along the first longitudinal axis, a plurality of strain gauges disposed on the sense surface, a second body having a sidewall forming a recess and being attached to the outer periphery of the first body, the second body having a second longitudinal axis generally coincident with the first longitudinal axis when the first 11 and second bodies are attached to one another, a second post extending outwardly from the second body along the second longitudinal axis, and a circumferential groove formed in the outer surface of the first body forming a web extending between the outer periphery of the first body and the portion of the first body formed with the flat sense surface. - View Dependent Claims (16)
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17. An occupant weight sensor comprising:
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a sense element having a first generally cylindrical metallic body having a first longitudinal axis and having a generally planar sense surface lying in a plane generally perpendicular to the first longitudinal axis, the first body having an outer periphery and a first post extending outwardly from the first body along the first longitudinal axis, a full Wheatstone bridge comprising four piezoresistors affixed to selected locations on the sense surface, a printed circuit board disposed on the sense surface and being configured to leave an opening over each piezoresistor, conditioning electronics mounted on the printed circuit board and formed with selected electrical paths, the piezoresistors electrically connected to form a bridge and electrically coupled to the conditioning electronics and selected circuit paths, a ring circumscribing the printed circuit board and being attached to the first body, the ring formed with contact holder retention features, a contact holder having ring retention features cooperating with the contact holder retention features, the contact holder received on the ring and attached thereto through the retention features, a plurality of contact members mounted on the contact holder, a second generally cylindrical body having a second longitudinal axis and having a sidewall formed with a recess, the sidewall fixed to the outer periphery of the first body with the second longitudinal axis generally coincident with the first longitudinal axis, a second post extending outwardly from the second body along the second longitudinal axis, an opening formed in the sidewall, and a connector received through the opening, the connector having a plurality of electrical terminals and the contact members of the contact holder extending from the respective terminals of the connector to respective selected circuit paths on the printed circuit board. - View Dependent Claims (18, 19, 20, 21)
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Specification