Vehicle occupant weight estimation apparatus having fluid-filled multi-cell seat bladder

• US 6,101,436 A
• Filed: 02/18/1998
• Issued: 08/08/2000
• Est. Priority Date: 09/03/1997
• Status: Expired due to Term

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delco Electronics Corporation (General Motors Company)
• Inventors: Fortune, Duane Donald, Roe, Pamela Ann, Myers, Robert Joseph, Murphy, Morgan Daniel
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US09/028,869
• Time in Patent Office: 902 Days
• Field of Search: 701/45, 701/36, 701/49, 280/735, 280/734, 280/730.1, 180/273, 180/282, 180/268, 180/271, 177/209, 297/DIG. 3, 297/452.41, 297/195.12, 297/284.6, 340/436, 340/666, 340/667, 340/665
• US Class Current: 701/45
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60N 2/0024 for identifying, categorising or investigation of the occupant or object on the seat
• CPC Class Codes: B60N 2/003 characterised by the sensor mounting location in or on the seat
• CPC Class Codes: B60N 2210/30 Temperature sensors
• CPC Class Codes: B60N 2210/44 using fluids
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/0152 using strain gauges
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015
• CPC Class Codes: G01G 5/04 with means for measuring the pressure imposed by the load on a liquid pressure gauges per se G01L
• CPC Class Codes: G01L 1/02 by hydraulic or pneumatic means

Abstract

An improved weight estimation apparatus in which a closed, multiple cell elastomeric bladder filled with fluid is installed in the foam cushion of a vehicle seat bottom, with at least one pressure sensor installed in a closed exit port of the bladder. The multiple cells of the bladder are formed by a pattern of spot welds between the top and bottom layers of the bladder, creating an array of generally circular or hexagonal cells between which the fluid can freely flow. The array of cells maximizes the pressure response for improved sensitivity, and minimizes the amount of fluid required to detect occupant weight, thereby minimizing the weight of the fluid-filled bladder. The pattern of spot welds in the vicinity of the pressure sensing location may be altered to reduce sensitivity to forces applied in proximity to the exit port. In a first embodiment, a more dense pattern of spot welds is provided in the vicinity of the exit port, while in a second embodiment, continuous welding is used to form a pattern of closed fluid-free pockets in the vicinity of the exit port.

Claims

1. Apparatus for estimating the weight of an occupant of a seat in a motor vehicle, the seat having a foam cushion bottom, the apparatus comprising:

a fluid-filled bladder disposed in the foam cushion bottom, the bladder comprising top and bottom sheets of elastomeric material with a continuous seam about their periphery to form a closed volume, a plurality of spot welds between said top and bottom sheets, said spot welds being distributed over said bladder, thereby dividing said bladder into a contiguous array of generally circular cells with free flow of said fluid between adjacent cells, the bladder being substantially filled with fluid, and an exit port disposed in said bottom sheet, substantially centered in a central one of said cells positioned at a center of gravity of said fluid;

a pressure sensor coupled to said exit port for sealing said exit port and for sensing the pressure of said fluid; and

control means for estimating the weight of the occupant based on the sensed fluid pressure.

2. The apparatus of claim 1, wherein there is an increased density of said spot welds in a central region of said bladder surrounding said exit port thereby forming a second plurality of contiguous cells in said central region which are smaller than the contiguous cells disposed outside of said central region.

3. The apparatus of claim 1, including additional welds in a central region of said bladder surrounding said exit port, said additional welds forming a plurality of closed, fluid-free cells in said central region, spaced generally symmetrically with respect to said exit port, and being generally triangular in shape.

4. The apparatus of claim 1, wherein said control means provides an input to an air bag deployment system, said input indicating whether deployment should be inhibited or allowed based on the estimated weight of the occupant.