Seat weight sensor having fluid filled bladder

• US 5,957,491 A
• Filed: 12/18/1997
• Issued: 09/28/1999
• Est. Priority Date: 12/19/1996
• Status: Expired due to Term

• Current Assignee: Joyson Safety Systems Acquisition, LLC
• Original Assignee: Automotive Systems Laboratory, Incorporated (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Cech, Leonard S., Sewell, Michael R., Stanley, James G., Palmer, Dennis E., Gillis, Edward J., Bowman, Todd K., Tran, Vinh H.
• Primary Examiner(s): Dickson, Paul N.
• Assistant Examiner(s): JASMIN, LYNDA C
• Application Number:
  US08/993,701
• Time in Patent Office: 649 Days
• Field of Search: 280/727, 280/735, 180/273, 180/269, 340/667, 297/217.2, 297/DIG. 3, 73/756, 177/208, 177/209, 177/254
• US Class Current: 280/735
• 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: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/01522 using fluid means
• 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: Y10S 297/03 Pneumatic

Abstract

A seat weight sensor incorporates a fluid containing bladder placed in series with the load path in the seat, whereby a load applied to and distributed across the bladder increases the pressure of the fluid therein. The pressure of the fluid is measured by a pressure sensor and is substantially proportional to the magnitude of the applied load, and substantially inversely proportional to the supported area of the bladder. The output signal is substantially linear with respect to weight. Preferably, the amount of fluid in the bladder should be less than the capacity of the bladder when the bladder is unloaded. The seat weight sensor is incorporated into an occupant restraint system for controlling the safety restraint system responsive to the weight of the occupant.

Claims

1. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto, comprising:

a. a bladder mounted beneath the cushion of the seat and supported by the base of the seat, where in said bladder is constructed from a flexible material;

b. a fluid contained by said bladder, the volume of said fluid in said bladder being less than the capacity of said bladder in the absence of an external load applied to said bladder;

c. a pressure sensor operatively coupled to said bladder for generating a signal responsive to the pressure of said fluid within said bladder; and

d. a signal processor for measuring the weight of the occupant from said signal for generating a control signal for controlling the safety restraint system responsive to said weight measurement.

2. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said fluid is a gas.

3. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said pressure sensor is responsive to the absolute pressure of said fluid within said bladder.

4. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto as recited in claim 1, wherein said pressure sensor is responsive to the differential pressure of said fluid within said bladder relative to local atmospheric pressure.

5. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto, comprising:

a. a bladder mounted beneath the cushion of the seat and supported by the base of the seat, wherein said bladder comprises a plurality of sheets of coated fabric sealably connected to one another at a periphery so as to form an inflatable confinement within said periphery whereby said sheets of coated fabric are further connected to one another at one or more locations within said periphery so as to create a plurality of fluid containing zones within said inflatable confinement which are in fluid communication with one another;

b. a fluid contained by said bladder;

c. a pressure sensor operatively coupled to said bladder for generating a signal responsive to the pressure of said fluid within said bladder; and

d. a signal processor for measuring the weight of the occupant from said signal for generating a control signal for controlling the safety restraint system responsive to said weight measurement.

6. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto as recited in claim 5, wherein said fluid containing zones are non-uniformly distributed within said periphery.

7. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto as recited in claim 6, wherein said sheets of coated fabric are further connected to one another along one or more closed paths within said periphery.

8. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto as recited in claim 5, further comprising a coating on the outside of at least one load bearing surface of said bladder, the volume of said fluid in said bladder being less that the capacity of said bladder in the absence of an external load applied to said bladder, wherein said pressure sensor is responsive to the differential pressure of said fluid within said bladder relative to local atmospheric pressure, wherein said pressure sensor is isolated from said fluid by the surface of said bladder, further comprising a restraint located on the inside of said bladder proximate said pressure sensor, whereby said restraint prevents said bladder from collapsing proximate said pressure sensor.

9. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto as recited in claim 8, wherein said fluid containing zones are non-uniformly distributed within said periphery.

10. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto as recited in claim 9, wherein said sheets of coated fabric are further connected to one another along one or more closed paths within said periphery.

11. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto as recited in claim 8, wherein said sheets of coated fabric are further connected to one another along one or more closed paths within said periphery.

12. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto, comprising:

a. a bladder mounted beneath the cushion of the seat and supported by the base of the seat, wherein said bladder is constructed from a flexible material,

b. a sheet of semi-rigid material proximate a load bearing surface of said bladder;

c. a fluid contained by said bladder;

d. a pressure sensor operatively coupled to said bladder for generating a signal responsive to the pressure of said fluid within said bladder; and

e. a signal processor for measuring the weight of the occupant from said signal for generating a control signal for controlling the safety restraint system responsive to said weight measurement.

13. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto, comprising:

a. a bladder mounted beneath the cushion of the seat and supported by the base of the seat wherein said bladder is constructed from a flexible material;

b. a coating on the outside of at least one load bearing surface of said bladder;

c. a fluid contained by said bladder;

d. a pressure sensor operatively coupled to said bladder for generating a signal responsive to the pressure of said fluid within said bladder; and

e. a signal processor for measuring the weight of the occupant from said signal for generating a control signal for controlling the safety restraint system responsive to said weight measurement.

14. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto, comprising:

a. a bladder mounted beneath the cushion of the seat and supported by the base of the seat, wherein said bladder is constructed from a flexible material;

b. a fluid contained by said bladder, wherein said fluid is a liquid;

c. a pressure sensor operatively couipled to said bladder for generating a signal responsive to the pressure of said fluid within said bladder; and

d. a signal processor for measuring the weight of the occupant from said signal for generating a control signal for controlling the safety restraint system responsive to said weight measurement.

15. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto as recited in claim 14, whereby said fluid is a silicone based fluid.

16. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto, comprising:

a. a bladder mounted beneath the cushion of the seat and supported by the base of the seat, wherein said bladder is constructed from a flexible material;

b. a fluid contained by said bladder;

c. a pressure sensor operatively coupled to said bladder for generating a signal responsive to the pressure of said fluid within said bladder, wherein said pressure sensor is responsive to the strain in the surface of said bladder; and

d. a signal processor for measuring the weight of the occupant from said signal for generating a control signal for controlling the safety restraint system responsive to said weight measurement.

17. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto, comprising:

a. a bladder mounted beneath the cushion of the seat and supported by the base of the seat, wherein said bladder is constructed from a flexible material,

b. a fluid contained by said bladder;

c. a pressure sensor operatively coupled to said bladder for generating a signal responsive to the pressure of said fluid within said bladder, wherein said pressure sensor is internally integrated within said bladder and

d. a signal processor for measuring the weight of the occupant from said signal for generating a control signal for controlling the safety restraint system responsive to said weight measurement.

18. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto, comprising:

a. a bladder mounted beneath the cushion of the seat and supported by the base of the seat, wherein said bladder is constructed from a flexible material;

b. a fluid contained by said bladder;

c. a pressure sensor operatively coupled to said bladder for generating a signal responsive to the pressure of said fluid within said bladder, wherein said pressure sensor is isolated from said fluid by the surface of said bladder and

d. a signal processor for measuring the weight of the occupant from said signal for generating a control signal for controlling the safety restraint system responsive to said weight measurement.

19. A system for measuring the weight of an occupant in a vehicle seat and for controlling a safety restraint system responsive thereto as recited in claim 18, further comprising a restraint located on the inside of said bladder proximate said pressure sensor, whereby said restraint prevents said bladder from collapsing proximate said pressure sensor.

20. A system for controlling a safety restraint system responsive to the weight on a vehicle seat, comprising:

a. a fluid containing means operatively coupled to the vehicle seat for generating a pressure within said fluid responsive to the weight on the vehicle seat, wherein said fluid containing means is partially filled with said fluid;

b. a means for sensing the pressure of said fluid; and

c. a means for controlling the safety restraint system responsive to the pressure of said fluid.

21. A system for controlling a safety restraint system responsive to the weight on a vehicle seat as recited in claim 20 further comprising a means for distributing the weight over said fluid containing means.

22. A system for controlling a safety restraint system responsive to the weight on a vehicle seat, comprising:

a. a fluid confinement operatively coupled to the vehicle seat whereby the pressure of said fluid is responsive to the weight on the vehicle seat, wherein said fluid confinement is partially filled with said fluid;

b. a pressure sensor operatively coupled to said fluid confinement for generating a signal responsive to the pressure of said fluid; and

c. a signal processor operatively coupled to said pressure sensor for controlling the safety restraint system responsive to said signal.

23. A system for controlling a safety restraint system responsive to the weight on a vehicle seat as recited in claim 22 further comprising a load distributor whereby said load distributor distributes the weight on the vehicle seat over at least a portion of the surface of said fluid confinement.

24. A method for controlling a safety restraint system responsive to the weight of an occupant in a vehicle seat, comprising:

a. interposing a hydrostatic weight sensor in series with the load path that supports the occupant in the vehicle seat, whereby said hydrostatic weight sensor is partially filled with a fluid and incorporates a pressure sensor in fluid communication therewith, said pressure sensor generates a signal responsive to the pressure of said fluid, and said pressure is responsive to the component of occupant weight applied by the occupant on the vehicle seat to said hydrostatic weight sensor; and

b. controlling the safety restraint system responsive to said signal responsive to the pressure of said fluid.

25. A method for controlling a safety restraint system responsive to the weight of an occupant in a vehicle seat as recited in claim 24 further comprising the act of distributing said fluid within a plurality of zones in fluid communication with one another within said bladder.

26. A method for controlling a safety restraint system responsive to the weight of an occupant in a vehicle seat as recited in claim 25, further comprising the act of non-uniformly distributing said plurality of zones within said bladder.

27. A method for controlling a safety restraint system responsive to the weight of an occupant in a vehicle seat as recited in claim 24, further comprising the act of forming at least one zone within said bladder, whereby said at least one zone is not in fluid communication with said pressure sensor.

28. A method for controlling a safety restraint system responsive to the weight of an occupant in a vehicle seat as recited in claim 24 whereby said pressure sensor senses the pressure of said fluid from the outside of said bladder.

29. A method for controlling a safety restraint system responsive to the weight of an occupant in a vehicle seat as recited in claim 28, further comprising the act of preventing said bladder from interfering with the operation of said pressure sensor.

30. A method for controlling a safety restraint system responsive to the weight of an occupant in a vehicle seat as recited in claim 24 wherein said safety restraint system comprises an air bag inflation system, and the act of controlling said safety restraint system comprises controlling the inflation rate of said air bag inflation system.

31. A method of manufacturing a hydrostatic occupant weight sensor, comprising:

a. securing first and second portions of coated fabric to one another along a periphery, so as to form a confinement, said confinement having an opening;

b. securing said first and second portions of said coated fabric to one another within said periphery so as to create a plurality of zones within said periphery in fluid communication with one another;

c. operatively coupling a pressure sensor to said confinement;

d. at least partially filling said confinement with a fluid through said opening in said confinement; and

e. sealing said opening in said confinement.

32. A method of manufacturing a hydrostatic occupant weight sensor as recited in claim 31, wherein said plurality of zones are characterized by a plurality of shapes.

33. A method of manufacturing a hydrostatic occupant weight sensor as recited in claim 31, wherein, wherein said plurality of zones are characterized by a plurality of sizes.

34. A method of manufacturing a hydrostatic occupant weight sensor as recited in claim 31, wherein said pressure sensor is isolated from said fluid by said coated fabric.

35. A method of manufacturing a hydrostatic occupant weight sensor as recited in claim 31, further comprising the step of installing a restraint within said confinement to prevent said confinement from interfering with the operation of said pressure sensor.

36. A method of manufacturing a hydrostatic occupant weight sensor as recited in claim 31, wherein the step of securing said first and second portions of said coated fabric comprises welding.

37. A method of manufacturing a hydrostatic occupant weight sensor as recited in claim 31, wherein said fluid is a silicone based fluid.

38. A method of manufacturing a hydrostatic occupant weight sensor as recited in claim 31, wherein said confinement is partially filled with said fluid.