WO1999012012A1 - Apparatus to measure seat belt tension - Google Patents

Apparatus to measure seat belt tension Download PDF

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Publication number
WO1999012012A1
WO1999012012A1 PCT/US1998/016837 US9816837W WO9912012A1 WO 1999012012 A1 WO1999012012 A1 WO 1999012012A1 US 9816837 W US9816837 W US 9816837W WO 9912012 A1 WO9912012 A1 WO 9912012A1
Authority
WO
WIPO (PCT)
Prior art keywords
seat belt
seat
tension
electrical device
force sensitive
Prior art date
Application number
PCT/US1998/016837
Other languages
French (fr)
Inventor
Robert Perry Pettypiece, Jr.
Edward Ronald Stembler
Original Assignee
Breed Automotive Technology, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Breed Automotive Technology, Inc. filed Critical Breed Automotive Technology, Inc.
Publication of WO1999012012A1 publication Critical patent/WO1999012012A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
    • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
    • B60R21/015—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting the presence or position of passengers, passenger seats or child seats, and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
    • B60R21/01512—Passenger detection systems
    • B60R21/01544—Passenger detection systems detecting seat belt parameters, e.g. length, tension or height-adjustment
    • B60R21/0155—Passenger detection systems detecting seat belt parameters, e.g. length, tension or height-adjustment sensing belt tension
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
    • B60R21/01—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents
    • B60R21/015—Electrical circuits for triggering passive safety arrangements, e.g. airbags, safety belt tighteners, in case of vehicle accidents or impending vehicle accidents including means for detecting the presence or position of passengers, passenger seats or child seats, and the related safety parameters therefor, e.g. speed or timing of airbag inflation in relation to occupant position or seat belt use
    • B60R21/01556—Child-seat detection systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R22/00—Safety belts or body harnesses in vehicles
    • B60R22/18—Anchoring devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
    • G01L5/10—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands using electrical means
    • G01L5/102—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands using electrical means using sensors located at a non-interrupted part of the flexible member
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
    • G01L5/10—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands using electrical means
    • G01L5/103—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands using electrical means using sensors fixed at one end of the flexible member
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/04—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands
    • G01L5/10—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands using electrical means
    • G01L5/108—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring tension in flexible members, e.g. ropes, cables, wires, threads, belts or bands using electrical means for measuring a reaction force applied on a single support, e.g. a glider

Definitions

  • the present invention relates to an apparatus for evaluating tension in a seat belt of the type employed in a motor vehicle.
  • An apparatus for evaluating tension in a seat belt in accordance with the present invention can either: (a) directly enable or disable the activation of a vehicle occupant safety device; or (b) provide an additional input signal to the weight sensing device, and/or a device controlling the activation of vehicle occupant safety devices, indicating the amount of tension on a seat belt associated with a seat.
  • the weight sensing device, and/controller may process this input to compensate for excessive force transferred through the seat cushion to the force sensing assembly as a result of excessive seat belt tension on an infant or child seat.
  • EP 0 721 863 A2 teaches an apparatus for detecting whether an infant or child seat is mounted on a vehicle seat employing eight variable resistance pressure sensors in the seat cushion to determine the total weight supported by the seat cushion and the weight distribution. This apparatus may be used in conjunction with seat belt fastening detection to indicate when a seat is occupied and the seat belt is not fastened.
  • Fig. 1 is a diagrammatic representation of a prior art vehicle seat with a child seat secured thereto by a prior art seat belt;
  • Fig. 2 is an exploded fragmentary perspective view of an apparatus for evaluating tension in a seat belt according to an embodiment of the present invention
  • Fig. 3 is a front elevation view, partially broken away, of the embodiment of Fig. 2;
  • Fig. 4 is a side elevation view, in section along line 4-4 of Fig. 3, of the embodiment of Fig. 2;
  • Fig. 5 is a side elevation view, in section of an alternative embodiment of an apparatus for evaluating tension in a seat belt according to the present invention .
  • FIG. 1 there is shown a diagrammatic representation of a prior art vehicle seat having a seat cushion 10 and a seat back 12 with a conventional infant or child seat 14 secured thereby a conventional seat belt.
  • a conventional seat lap belt has two lengths 16, 18 of seat belt material separately linked together by a buckle 20.
  • one of the lengths of seat belt material is secured to an anchor 22 which is retained in a fixed orientation with respect to a structural member of a vehicle by a means for attachment 24, such as screws, bolts, rivets, welding and so forth.
  • An occupant sensing apparatus 26 is located in the seat cushion 10 to sense the weight supported by the seat cushion.
  • US 5 494 311 discloses a film having an electrical characteristic with changeable states and a contact member.
  • the contact member pushes on the film and changes the state of the electrical characteristic.
  • An electric circuit is connected to the film for providing signals relating to seat occupant presence, weight and position.
  • the device for sensing the weight supported by the seat cushion may communicate with a device controlling the activation of vehicle occupant safety devices such as airbags and seat belt pretensioners . It has been observed that while such devices may be capable of determining the weight of a vehicle seat occupant satisfactorily in most circumstances, erroneous results may be obtained when an infant or child safety seat is located on a seat equipped with such a weighing device. There is a limit on the amount of tension on a lap belt, or the lap portion of a three point safety belt, which can be comfortably tolerated by the flesh of a human seat occupant.
  • an infant or child seat which is made of a plastic material can tolerate a higher amount of tension from a lap belt, or the lap portion of a three point safety belt, employed to secure the infant seat or child seat to a vehicle seat.
  • This excessive seat belt tension on the infant or child seat may result in excessive force being transmitted through the seat cushion to a seat force sensing device used for weighing a seat occupant.
  • the device used for weighing a seat occupant may therefore communicate to a device controlling the activation of vehicle occupant safety devices that the seat is occupied by an occupant that weighs more than the actual combined weight of an infant, or child, seat and the associated infant, or child.
  • FIG. 2 an exploded fragmentary perspective view of an apparatus for evaluating tension in a seat belt according to an embodiment of the present invention, with Fig. 3 being a front elevation view, partially broken away, of the embodiment of Fig. 2, and Fig. 4 being a side elevation view, in section along line 4-4 of Fig. 3, of the embodiment of Fig. 2.
  • An apparatus 30 for evaluating tension in a seat belt has a rigid member 34 retained in a fixed orientation with respect to a structural member 32 of a vehicle.
  • the structural member of a vehicle may extend at any angle with respect to the floor of the vehicle and may for example be a floor member of a vehicle, a pillar member of a vehicle, or a substantially vertically oriented seat supporting member of a vehicle.
  • the angular orientation of the rigid member 34 may be adjusted to compensate for its location in a vehicle and the configuration of the seating of a vehicle.
  • the rigid member 34 is retained in a fixed orientation by any suitable fastening means such as a bolt 35, riveting, welding and so forth.
  • a resilient member 36 is attached to the rigid member 34.
  • the resilient member is a metallic spring which is attached to the rigid member by any suitable attachment means such as spot welds 38, bolts or rivets. It is understood that any suitable resilient member may be employed in the disclosed apparatus such as a coil spring, a hinged lever arm, or a compressible structure formed of a polymeric material.
  • a first portion 50 of a length of conventional seat belt material 40 is anchored in a fixed orientation with respect to the structural member 32 of the vehicle by looping the seat belt material through an aperture 44 in an anchor member 42 which is in turn fixed in place by the fastening means 35.
  • a washer 37 separates the anchor member 42 from the rigid member 34.
  • the loop in the seat belt material is closed by stitches 46.
  • a second portion 52 of the length of seat belt material 40 is disposed on a side of the resilient member 36 that is distal from the rigid member 34.
  • a third portion 54 of the length of seat belt material 40 extends through an aperture 48 in the rigid member 34.
  • the resilient member 36 is at least partially disposed between the aperture 48 n the rigid member and the first portion 50 of the length of seat belt material.
  • the third portion extends to a buckle (not shown) that is attached to the length of seat belt material.
  • the resilient member partially overlaps the aperture to guide the seat belt material into the aperture.
  • a shroud 60 may be fitted to the apparatus for aesthetic purposes and to protect the apparatus from foreign objects and damage.
  • the length of seat belt material 40 may be attached to a second length of seat belt material by a buckle. These two lengths of seat belt material cooperate to act as a lap belt to secure an occupant or an infant or child seat in a vehicle seat in the usual manner. It is further understood that the second length of seat belt material is secured at the end opposite the buckle to a seat belt retractor device and or pretensioner device in the usual manner, and that a third length of seat belt material may be joined to the second length to serve as a shoulder belt in a manner that is well known m the art.
  • a force sensitive electrical device 56 is disposed between the rigid member 34 and the resilient member 36.
  • the force sensitive electrical device 56 is a pressure switch which is in circuit communication, for example thorough leads 58, with a vehicle occupant safety device to enable or disable the activation of a vehicle occupant safety device.
  • the force sensitive electrical device is in circuit communication, for example thorough leads 58, with a signal processing device (not shown) which processes a signal from the force sensitive electrical device to evaluate the tension on the length of seat belt material.
  • the term "in circuit communication" is used to describe (I) devices that are directly or indirectly electrically connected with each other, (n) devices having other devices or combinations of devices (e.g.
  • breakers breakers, relays, buffers, drivers, transmitters, receivers, and decoders between them, (m) devices in optoisolator or fiber optic link, (IV) devices m electromagnetic communication with each other (via, e.g. radio frequency transmitter and receiver pair) , (v) devices connected by and through other structures allowing them to communicate with each other, and (vi) any combination of the above.
  • the force sensitive electrical device may be for example a pressure switch, a strain gauge, a load cell, a magnetostrictive sensor, a capacitive pressure sensor, or a variable resistance pressure sensor.
  • a working prototype of a vehicle seat equipped with an apparatus for evaluating tension in a seat belt m accordance with the present invention employed a sensor which is a Model 14 compression only subminiature load cells purchased from Sensotec, Inc. of 1200 Chesapeake Avenue, Columbus, Ohio U.S.A. This sensor is available with a range of either 45.4 kilograms or 113.5 kilograms. The height of these sensors is 3.8 millimeters.
  • the seat belt material urges the resilient member 36 towards the rigid member and a resultant force is sensed by the force sensitive electrical device 56 which is operatively interposed between the resilient member and the rigid member.
  • the force sensitive electrical device transmits a signal to a signal processing device with processes the signal, or a series of such signals, to evaluate the tension on the length of seat belt material.
  • the signal processing device can simply evaluate if the tension is below or above a selected threshold, or can be so sophisticated as to determine the actual value of the tension in selected units.
  • the signal processing device may be in circuit communication with a seat occupant weighing device or with a device which controls the activation of vehicle occupant safety devices such as airbags and pretensioners, and can generate signals which are transmitted thereto. Accordingly, the tension is a length of seat belt material detected by an apparatus of the present invention can be factored into a decision as to whether or not a vehicle seat is supporting an infant or child seat that is secured m place by the seat belt.
  • FIG. 5 there is shown a side elevation view, m section of an alternative embodiment of an apparatus 70 for evaluating tension in a seat belt according to the present invention.
  • the rigid member 72 is secured in a fixed relationship with a substantially horizontally extending floor 72 of a vehicle by a bolt 76.
  • a length of seat belt material 76 is looped through two apertures 80, 82 in the rigid member itself, rather than a separate anchor member as in the embodiment of Figs. 2-4.
  • a resilient member 84 and force sensitive electrical device 86 are assembled with the rigid member as described above with regards to the embodiment of Figs. 2-4, and the apparatus functions in the manner described above.
  • a shroud 88 may be fitted to the apparatus for aesthetic purposes and to protect the apparatus from foreign objects and damage .

Abstract

Tension in a seat belt is evaluated by a device which has a rigid member (34) retained in a fixed orientation with respect to a structural member (32) of a vehicle. A resilient member (36) is attached to the rigid member with a force sensitive electrical device (56) disposed between the rigid member and the resilient member. When the seat belt is subjected to tension it presses against the resilient member which in turn exerts a force on the force sensitive electrical device. Preferably, the force sensitive electrical device is in circuit communication with a device which processes a signal from the force sensitive electrical device to evaluate the tension on the seat belt.

Description

APPARATUS TO MEASURE SEAT BELT TENSION
The present invention relates to an apparatus for evaluating tension in a seat belt of the type employed in a motor vehicle.
In the field of safety devices for motor vehicle occupants there has been considerable interest in developing devices to determine the weight supported by the seat cushion of a vehicle seat and in devices for detecting the presence of an infant or child seat on a vehicle seat. It has been observed that if the seat belt used to secure an infant or child seat to a vehicle seat is cinched too tightly the associated weight sensing device in the vehicle seat may detect a weight greater than the actual wight of the infant or child seat and the infant or child it contains.
An apparatus for evaluating tension in a seat belt in accordance with the present invention can either: (a) directly enable or disable the activation of a vehicle occupant safety device; or (b) provide an additional input signal to the weight sensing device, and/or a device controlling the activation of vehicle occupant safety devices, indicating the amount of tension on a seat belt associated with a seat. The weight sensing device, and/controller, may process this input to compensate for excessive force transferred through the seat cushion to the force sensing assembly as a result of excessive seat belt tension on an infant or child seat. EP 0 721 863 A2 teaches an apparatus for detecting whether an infant or child seat is mounted on a vehicle seat employing eight variable resistance pressure sensors in the seat cushion to determine the total weight supported by the seat cushion and the weight distribution. This apparatus may be used in conjunction with seat belt fastening detection to indicate when a seat is occupied and the seat belt is not fastened.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention may take physical form in certain parts and arrangement of parts, a preferred embodiment of which will be described in detail in this description and illustrated in the accompanying drawings which form a part hereof and wherein:
Fig. 1 is a diagrammatic representation of a prior art vehicle seat with a child seat secured thereto by a prior art seat belt;
Fig. 2 is an exploded fragmentary perspective view of an apparatus for evaluating tension in a seat belt according to an embodiment of the present invention; Fig. 3 is a front elevation view, partially broken away, of the embodiment of Fig. 2;
Fig. 4 is a side elevation view, in section along line 4-4 of Fig. 3, of the embodiment of Fig. 2; and
Fig. 5 is a side elevation view, in section of an alternative embodiment of an apparatus for evaluating tension in a seat belt according to the present invention .
DETAILED DESCRIPTION OF THE INVENTION
Referring first to Fig. 1, there is shown a diagrammatic representation of a prior art vehicle seat having a seat cushion 10 and a seat back 12 with a conventional infant or child seat 14 secured thereby a conventional seat belt. A conventional seat lap belt has two lengths 16, 18 of seat belt material separately linked together by a buckle 20. Typically one of the lengths of seat belt material is secured to an anchor 22 which is retained in a fixed orientation with respect to a structural member of a vehicle by a means for attachment 24, such as screws, bolts, rivets, welding and so forth. An occupant sensing apparatus 26 is located in the seat cushion 10 to sense the weight supported by the seat cushion. One example of such a weight sensing apparatus is taught in US 5 494 311 which discloses a film having an electrical characteristic with changeable states and a contact member. When the vehicle seat is occupied, the contact member pushes on the film and changes the state of the electrical characteristic. An electric circuit is connected to the film for providing signals relating to seat occupant presence, weight and position.
The device for sensing the weight supported by the seat cushion may communicate with a device controlling the activation of vehicle occupant safety devices such as airbags and seat belt pretensioners . It has been observed that while such devices may be capable of determining the weight of a vehicle seat occupant satisfactorily in most circumstances, erroneous results may be obtained when an infant or child safety seat is located on a seat equipped with such a weighing device. There is a limit on the amount of tension on a lap belt, or the lap portion of a three point safety belt, which can be comfortably tolerated by the flesh of a human seat occupant. However, an infant or child seat which is made of a plastic material can tolerate a higher amount of tension from a lap belt, or the lap portion of a three point safety belt, employed to secure the infant seat or child seat to a vehicle seat. This excessive seat belt tension on the infant or child seat may result in excessive force being transmitted through the seat cushion to a seat force sensing device used for weighing a seat occupant. It follows that the device used for weighing a seat occupant may therefore communicate to a device controlling the activation of vehicle occupant safety devices that the seat is occupied by an occupant that weighs more than the actual combined weight of an infant, or child, seat and the associated infant, or child. Referring next to Figs. 2-4 there is shown in
Fig. 2 an exploded fragmentary perspective view of an apparatus for evaluating tension in a seat belt according to an embodiment of the present invention, with Fig. 3 being a front elevation view, partially broken away, of the embodiment of Fig. 2, and Fig. 4 being a side elevation view, in section along line 4-4 of Fig. 3, of the embodiment of Fig. 2. An apparatus 30 for evaluating tension in a seat belt has a rigid member 34 retained in a fixed orientation with respect to a structural member 32 of a vehicle. The structural member of a vehicle may extend at any angle with respect to the floor of the vehicle and may for example be a floor member of a vehicle, a pillar member of a vehicle, or a substantially vertically oriented seat supporting member of a vehicle. It is understood that the angular orientation of the rigid member 34 may be adjusted to compensate for its location in a vehicle and the configuration of the seating of a vehicle. The rigid member 34 is retained in a fixed orientation by any suitable fastening means such as a bolt 35, riveting, welding and so forth.
A resilient member 36 is attached to the rigid member 34. In the embodiments illustrated herein the resilient member is a metallic spring which is attached to the rigid member by any suitable attachment means such as spot welds 38, bolts or rivets. It is understood that any suitable resilient member may be employed in the disclosed apparatus such as a coil spring, a hinged lever arm, or a compressible structure formed of a polymeric material. In the embodiment of Figs. 2-4 a first portion 50 of a length of conventional seat belt material 40 is anchored in a fixed orientation with respect to the structural member 32 of the vehicle by looping the seat belt material through an aperture 44 in an anchor member 42 which is in turn fixed in place by the fastening means 35. In this example a washer 37 separates the anchor member 42 from the rigid member 34. The loop in the seat belt material is closed by stitches 46. A second portion 52 of the length of seat belt material 40 is disposed on a side of the resilient member 36 that is distal from the rigid member 34. A third portion 54 of the length of seat belt material 40 extends through an aperture 48 in the rigid member 34. The resilient member 36 is at least partially disposed between the aperture 48 n the rigid member and the first portion 50 of the length of seat belt material. The third portion extends to a buckle (not shown) that is attached to the length of seat belt material. In the embodiments shown in the drawings the resilient member partially overlaps the aperture to guide the seat belt material into the aperture. A shroud 60 may be fitted to the apparatus for aesthetic purposes and to protect the apparatus from foreign objects and damage.
It is understood that the length of seat belt material 40 may be attached to a second length of seat belt material by a buckle. These two lengths of seat belt material cooperate to act as a lap belt to secure an occupant or an infant or child seat in a vehicle seat in the usual manner. It is further understood that the second length of seat belt material is secured at the end opposite the buckle to a seat belt retractor device and or pretensioner device in the usual manner, and that a third length of seat belt material may be joined to the second length to serve as a shoulder belt in a manner that is well known m the art.
A force sensitive electrical device 56 is disposed between the rigid member 34 and the resilient member 36. In a basic embodiment the force sensitive electrical device 56 is a pressure switch which is in circuit communication, for example thorough leads 58, with a vehicle occupant safety device to enable or disable the activation of a vehicle occupant safety device. Preferably, the force sensitive electrical device is in circuit communication, for example thorough leads 58, with a signal processing device (not shown) which processes a signal from the force sensitive electrical device to evaluate the tension on the length of seat belt material. As used herein and m the claims the term "in circuit communication" is used to describe (I) devices that are directly or indirectly electrically connected with each other, (n) devices having other devices or combinations of devices (e.g. breakers, relays, buffers, drivers, transmitters, receivers, and decoders) between them, (m) devices in optoisolator or fiber optic link, (IV) devices m electromagnetic communication with each other (via, e.g. radio frequency transmitter and receiver pair) , (v) devices connected by and through other structures allowing them to communicate with each other, and (vi) any combination of the above.
The force sensitive electrical device may be for example a pressure switch, a strain gauge, a load cell, a magnetostrictive sensor, a capacitive pressure sensor, or a variable resistance pressure sensor. A working prototype of a vehicle seat equipped with an apparatus for evaluating tension in a seat belt m accordance with the present invention employed a sensor which is a Model 14 compression only subminiature load cells purchased from Sensotec, Inc. of 1200 Chesapeake Avenue, Columbus, Ohio U.S.A. This sensor is available with a range of either 45.4 kilograms or 113.5 kilograms. The height of these sensors is 3.8 millimeters. When tension is placed on the length of seat belt material 40, as shown at T in Fig. 2, when the seat belt is pulled across the lap of a person or to secure an infant or child seat in place, the seat belt material urges the resilient member 36 towards the rigid member and a resultant force is sensed by the force sensitive electrical device 56 which is operatively interposed between the resilient member and the rigid member. In a preferred embodiment the force sensitive electrical device transmits a signal to a signal processing device with processes the signal, or a series of such signals, to evaluate the tension on the length of seat belt material. The signal processing device can simply evaluate if the tension is below or above a selected threshold, or can be so sophisticated as to determine the actual value of the tension in selected units. The signal processing device may be in circuit communication with a seat occupant weighing device or with a device which controls the activation of vehicle occupant safety devices such as airbags and pretensioners, and can generate signals which are transmitted thereto. Accordingly, the tension is a length of seat belt material detected by an apparatus of the present invention can be factored into a decision as to whether or not a vehicle seat is supporting an infant or child seat that is secured m place by the seat belt.
Referring next to Fig. 5 there is shown a side elevation view, m section of an alternative embodiment of an apparatus 70 for evaluating tension in a seat belt according to the present invention. In this example the rigid member 72 is secured in a fixed relationship with a substantially horizontally extending floor 72 of a vehicle by a bolt 76. A length of seat belt material 76 is looped through two apertures 80, 82 in the rigid member itself, rather than a separate anchor member as in the embodiment of Figs. 2-4. A resilient member 84 and force sensitive electrical device 86 are assembled with the rigid member as described above with regards to the embodiment of Figs. 2-4, and the apparatus functions in the manner described above. Once again a shroud 88 may be fitted to the apparatus for aesthetic purposes and to protect the apparatus from foreign objects and damage .

Claims

CLAIMS :
1. An apparatus for evaluating tension in a seat belt comprising: (a) a rigid member (34) retained in a fixed orientation with respect to a structural member (32) of a vehicle;
(b) a resilient member (36) attached to the rigid member; (c) a length of seat belt material (40), a first portion of said length of seat belt material being anchored in a fixed orientation with respect to said structural member of the vehicle, a second portion of said length of seat belt material being disposed on a side of the resilient member that is distal from said rigid member, a third portion of said length of seat belt material extending through an aperture in the rigid member wherein the resilient member is at least partially disposed between the aperture in the rigid member and the first portion of the length of seat belt material, said third portion extending to a buckle that is attached to said length of seat belt material; and
(d) a force sensitive electrical device (56) disposed between the rigid member and the resilient member .
2. An apparatus for evaluating tension in a seat belt according to claim 1 wherein said force sensitive electrical device (56) is a pressure switch.
3. An apparatus for evaluating tension in a seat belt according to claim 1 wherein the force sensitive electrical device (56) is in circuit communication with a signal processing device which processes a signal from said force sensitive electrical device to evaluate the tension on said length of seat belt material.
4. An apparatus for evaluating tension in a seat belt according to claim 3 wherein said force sensitive electrical device (56) is a strain gauge.
5. An apparatus for evaluating tension in a seat belt according to claim 3 wherein said force sensitive electrical device (56) is a load cell.
6. An apparatus for evaluating tension in a seat belt according to claim 3 wherein said force sensitive electrical device (56) is a variable resistance pressure sensor.
7. An apparatus for evaluating tension in a seat belt according to claim 3 wherein said force sensitive electrical device (56) is a capacitive pressure sensor.
8. An apparatus for evaluating tension in a seat belt according to claim 3 wherein said force sensitive electrical device (56) is a magnetostrictive sensor .
9. An apparatus for evaluating tension in a seat belt according to either of claims lor 3 wherein said resilient member (36) is a spring.
PCT/US1998/016837 1997-09-04 1998-08-12 Apparatus to measure seat belt tension WO1999012012A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US92323897A 1997-09-04 1997-09-04
US923,238 1997-09-04

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Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001002219A1 (en) * 1999-06-30 2001-01-11 Siemens Automotive Corporation Seat belt force sensor system
DE19941005A1 (en) * 1999-08-28 2001-03-01 Volkswagen Ag Belt force measurement arrangement has belt holders on either side of force measurement element bearer and connected to it to hold belt on either side of bearer, belt attachment devices
WO2001018507A1 (en) * 1999-09-10 2001-03-15 Siemens Automotive Corporation Method and apparatus for measuring seat occupant weight
US6209915B1 (en) * 1999-11-16 2001-04-03 Cts Corporation Seat belt tension sensor
WO2001053134A1 (en) * 2000-01-24 2001-07-26 Siemens Automotive Corporation Belt force sensor
WO2001079039A1 (en) * 2000-04-14 2001-10-25 Breed Automotive Technology, Inc. Seat belt tension sensing device
WO2001087676A2 (en) * 2000-05-12 2001-11-22 Siemens Automotive Corporation Seat belt force sensor system
WO2002026532A1 (en) * 2000-09-29 2002-04-04 Siemens Vdo Automotive Corporation Seatbelt force sensor assembly with guide member
EP1020320A3 (en) * 1999-01-14 2002-06-12 Toyota Jidosha Kabushiki Kaisha Sitting passenger detecting apparatus and sitting passenger detecting method
WO2001083275A3 (en) * 2000-05-04 2002-06-13 Breed Automotive Tech Seat belt tension sensor
WO2002026531A3 (en) * 2000-09-29 2002-07-18 Siemens Automotive Corp Lp Weight classification system
US6450534B1 (en) 2001-05-25 2002-09-17 Cts Corporation Seat belt tension sensor
GB2376925A (en) * 2001-06-29 2002-12-31 Finecard Internat Ltd Seat belt tension sensing device
US6578432B2 (en) 2001-06-19 2003-06-17 Cts Corporation Seat belt tension sensor
EP1337823A1 (en) * 2000-11-29 2003-08-27 Casco Products Corporation Webbing tension sensor
US6647811B2 (en) * 2001-06-19 2003-11-18 Cts Corporation Seat belt tension sensor with overload protection
DE10243344A1 (en) * 2002-09-18 2004-04-01 Siemens Ag Seat belt force measurement arrangement for measuring the force applied to a belt in order to optimize belt and air bag activation in an accident comprises a spring fixed at both ends with associated signaler and sensor
US6729194B2 (en) 2002-07-25 2004-05-04 Cts Corporation Hall effect seat belt tension sensor
US6776056B2 (en) 2001-08-06 2004-08-17 Cts Corporation Seat belt tension sensor
US6793032B2 (en) 2000-09-29 2004-09-21 Siemens Vdo Automotive Corporation Seatbelt force sensor assembly with guide member
US7086297B2 (en) 2001-08-06 2006-08-08 Cts Corporation Seat belt tension sensor having shock isolation
EP1707447A1 (en) * 2005-04-01 2006-10-04 Delphi Technologies, Inc. Optical seat belt tension sensor
US7263906B2 (en) 2001-06-19 2007-09-04 Cts Corporation Seat belt tension sensor
US7272979B2 (en) 2001-06-19 2007-09-25 Cts Corporation Seat belt tension sensor having an integral connector
US7347108B2 (en) 2001-06-19 2008-03-25 Cts Corporation Seat belt tension sensor
US7373845B2 (en) 2001-06-19 2008-05-20 Cts Corporation Seat belt tension sensor
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CN106004780A (en) * 2015-03-31 2016-10-12 福特全球技术公司 Seatbelt payout measuring device and system

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EP1837228A1 (en) 1999-01-14 2007-09-26 Toyota Jidosha Kabushiki Kaisha Sitting passenger detecting apparatus and sitting passenger detecting method
EP1839930A1 (en) 1999-01-14 2007-10-03 Toyota Jidosha Kabushiki Kaisha Sitting passenger detecting apparatus and sitting passenger detecting method
EP1020320A3 (en) * 1999-01-14 2002-06-12 Toyota Jidosha Kabushiki Kaisha Sitting passenger detecting apparatus and sitting passenger detecting method
WO2001002219A1 (en) * 1999-06-30 2001-01-11 Siemens Automotive Corporation Seat belt force sensor system
US6447010B1 (en) 1999-06-30 2002-09-10 Siemens Vdo Automotive Corporation Seat belt force sensor system
DE19941005B4 (en) * 1999-08-28 2010-04-08 Volkswagen Ag Belt force measuring device
DE19941005A1 (en) * 1999-08-28 2001-03-01 Volkswagen Ag Belt force measurement arrangement has belt holders on either side of force measurement element bearer and connected to it to hold belt on either side of bearer, belt attachment devices
WO2001018507A1 (en) * 1999-09-10 2001-03-15 Siemens Automotive Corporation Method and apparatus for measuring seat occupant weight
US6536797B1 (en) 1999-09-10 2003-03-25 Siemens Vdo Automotive Corporation Method and apparatus for measuring seat occupant weight
US6209915B1 (en) * 1999-11-16 2001-04-03 Cts Corporation Seat belt tension sensor
US6959779B2 (en) 2000-01-24 2005-11-01 Siemens Vdo Automotive Corporation Belt force sensor
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WO2001087676A2 (en) * 2000-05-12 2001-11-22 Siemens Automotive Corporation Seat belt force sensor system
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US6595545B2 (en) 2000-05-12 2003-07-22 Siemens Vdo Automotive Corporation Seat belt force sensor system
US7055400B2 (en) 2000-05-12 2006-06-06 Siemens Vdo Automotive Corporation Seat belt force sensor system
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US6860160B2 (en) 2000-05-12 2005-03-01 Siemens Vdo Automotive Corporation Seat belt force sensor system
WO2002026531A3 (en) * 2000-09-29 2002-07-18 Siemens Automotive Corp Lp Weight classification system
US6636792B2 (en) 2000-09-29 2003-10-21 Siemens Vdo Automotive Corporation Weight classification system
US7048085B2 (en) 2000-09-29 2006-05-23 Siemens Vdo Automotive Corporation Weight classification system
US7503417B2 (en) 2000-09-29 2009-03-17 Continental Automotive Systems Us, Inc. Sensor assembly for seat occupant weight classification system
WO2002026532A1 (en) * 2000-09-29 2002-04-04 Siemens Vdo Automotive Corporation Seatbelt force sensor assembly with guide member
US6793032B2 (en) 2000-09-29 2004-09-21 Siemens Vdo Automotive Corporation Seatbelt force sensor assembly with guide member
EP1337823A1 (en) * 2000-11-29 2003-08-27 Casco Products Corporation Webbing tension sensor
EP1337823A4 (en) * 2000-11-29 2005-07-20 Casco Products Corp Webbing tension sensor
US6450534B1 (en) 2001-05-25 2002-09-17 Cts Corporation Seat belt tension sensor
US7347108B2 (en) 2001-06-19 2008-03-25 Cts Corporation Seat belt tension sensor
US7373845B2 (en) 2001-06-19 2008-05-20 Cts Corporation Seat belt tension sensor
US6647811B2 (en) * 2001-06-19 2003-11-18 Cts Corporation Seat belt tension sensor with overload protection
US7272979B2 (en) 2001-06-19 2007-09-25 Cts Corporation Seat belt tension sensor having an integral connector
US6578432B2 (en) 2001-06-19 2003-06-17 Cts Corporation Seat belt tension sensor
US7263906B2 (en) 2001-06-19 2007-09-04 Cts Corporation Seat belt tension sensor
US6854415B2 (en) 2001-06-29 2005-02-15 Finecard International Limited Seat belt tension sensing device
GB2376925B (en) * 2001-06-29 2004-09-29 Finecard Internat Ltd A seat belt tension sensing device
GB2376925A (en) * 2001-06-29 2002-12-31 Finecard Internat Ltd Seat belt tension sensing device
US7086297B2 (en) 2001-08-06 2006-08-08 Cts Corporation Seat belt tension sensor having shock isolation
US6776056B2 (en) 2001-08-06 2004-08-17 Cts Corporation Seat belt tension sensor
US6729194B2 (en) 2002-07-25 2004-05-04 Cts Corporation Hall effect seat belt tension sensor
US7021162B2 (en) 2002-09-18 2006-04-04 Siemens Aktiengellschaft Belt force measuring device
DE10243344B4 (en) * 2002-09-18 2004-09-16 Siemens Ag Belt force measuring device
DE10243344A1 (en) * 2002-09-18 2004-04-01 Siemens Ag Seat belt force measurement arrangement for measuring the force applied to a belt in order to optimize belt and air bag activation in an accident comprises a spring fixed at both ends with associated signaler and sensor
EP1707447A1 (en) * 2005-04-01 2006-10-04 Delphi Technologies, Inc. Optical seat belt tension sensor
US7324191B2 (en) 2005-04-01 2008-01-29 Delphi Technologies, Inc. Optical seat belt tension sensor
DE102007035037A1 (en) * 2007-07-26 2009-01-29 Continental Automotive Gmbh Measuring device for determining pulling force e.g. belt force, in e.g. safety belt system, for motor vehicle, has measuring sensor e.g. hall sensor, measuring physical variable associated with deformation of element
CN106004780A (en) * 2015-03-31 2016-10-12 福特全球技术公司 Seatbelt payout measuring device and system
CN106004780B (en) * 2015-03-31 2020-12-04 福特全球技术公司 Safety belt pull-out measuring device and system

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