Vehicle seat air bladder pressure sensor

• US 5,904,219 A
• Filed: 01/15/1998
• Issued: 05/18/1999
• Est. Priority Date: 01/15/1998
• Status: Expired due to Term

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Xu, Liwen, Zwolinski, Joseph John, Anahid, Hassan
• Primary Examiner(s): Ellis, Christopher P.
• Application Number:
  US09/007,346
• Time in Patent Office: 488 Days
• Field of Search: 280/735, 180/273, 417/231, 297/DIG. 3, 297/284.1, 137/488, 702/51
• US Class Current: 180/273
• CPC Class Codes: A47C 31/126 for chairs
• CPC Class Codes: A61G 5/1043 Cushions specially adapted for wheelchairs
• CPC Class Codes: A61G 5/1045 for the seat portion
• 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 2/0033 mounted on or in the foam cushion
• CPC Class Codes: B60N 2/1665 Hydraulic or pneumatic actuation
• CPC Class Codes: B60N 2/914 Hydro-pneumatic adjustments of the shape
• CPC Class Codes: B60N 2210/44 using fluids
• CPC Class Codes: B60R 21/01516 using force or pressure sensing 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: G01G 5/006 with pneumatic means
• CPC Class Codes: Y10S 297/03 Pneumatic

Abstract

An air bladder type pressure sensor for a vehicle seat includes an integral pressure reservoir and interconnecting valves to keep the sensor membrane automatically properly inflated. An air pump refills the reservoir intermittently, while the reservoir keeps the membrane pressurized continually.

Claims

1. A vehicle seat surface air bladder type pressure sensor having an integrated inflation maintenance feature, comprising:

an air bladder comprising at least a flexible upper membrane with a perimeter and defining a pressurized sensing volume below said upper membrane having a predetermined operating pressure, said membrane being subject to inherent, continual air leakage that potentially reduces said operating pressure;

a pressure reservoir adjacent to said membrane perimeter and having an internal supply pressure substantially higher than said operating pressure, said reservoir having a substantially lower inherent air leakage;

an air supply pump connected to said pressure reservoir so as to activate and re pressurize said reservoir when said reservoir pressure falls to a threshold pressure intermediate said supply pressure and said operating pressure; and

,

at least one passive valve interconnecting said reservoir and sensing volume which opens to said reservoir when said bladder pressure falls below said operating pressure to admit higher pressure air from said reservoir and which closes when said operating pressure has been restored,

whereby said sensing volume is kept continually pressurized from said reservoir by said valve, while said pump is activated only when said reservoir pressure falls to said threshold pressure.

2. A vehicle seat surface air bladder type pressure sensor having an integrated inflation maintenance feature, comprising:

an air bladder comprising at least a flexible upper membrane with a perimeter and defining a pressurized sensing volume below said upper membrane having a predetermined operating pressure, said sensing volume having a predetermined operating thickness and being subject to inherent, continual leakage that potentially reduces said operating pressure;

a pressure reservoir adjacent to said membrane perimeter having a thickness less than said sensing volume thickness and having an internal supply pressure substantially higher than said operating pressure, said reservoir having a substantially lower inherent air leakage;

an air supply pump connected to said pressure reservoir so as to activate and re pressurize said reservoir when said reservoir pressure falls to a threshold pressure intermediate said supply pressure and said operating pressure; and

at least one passive valve interconnecting said reservoir and sensing volume which opens to said reservoir when said bladder pressure falls below said operating pressure to admit higher pressure air from said reservoir and which closes when said operating pressure has been restored,

whereby said sensing volume is kept continually pressurized from said reservoir by said valve and maintained continually thicker than said adjacent reservoir, while said pump is activated only when said reservoir pressure falls to said threshold pressure.

3. A vehicle seat surface air bladder type pressure sensor having an integrated inflation maintenance feature, comprising:

an air bladder comprising at least a flexible upper membrane with a perimeter and defining a pressurized sensing volume below said upper membrane having a predetermined operating pressure, said sensing volume having a predetermined operating thickness and being subject to inherent, continual leakage that potentially reduces said operating pressure;

a pressure reservoir surrounding and integrally formed with said membrane perimeter as a supporting frame thereto, said reservoir having a thickness less than said sensing volume thickness and having an internal supply pressure substantially higher than said operating pressure;

an air supply pump connected to said pressure reservoir so as to activate and re pressurize said reservoir when said reservoir pressure falls to a threshold pressure intermediate said supply pressure and said operating pressure; and

at least one passive valve interconnecting said reservoir and sensing volume which opens to said reservoir when said bladder pressure falls below said operating pressure to admit higher pressure air from said reservoir and which closes when said operating pressure has been restored,

whereby said sensing volume is kept continually pressurized from said reservoir by said valve and maintained continually thicker than said adjacent reservoir, while said pump is activated only when said reservoir pressure falls to said reservoir pressure.