[19]
`United States Patent
`[11] Patent Number:
`6,039,344
`[45] Date of Patent: Mar. 21, 2000
`Mehney et al.
`
`
`
`USOO6039344A
`
`[54]
`
`[75]
`
`VEHICLE OCCUPANT WEIGHT SENSOR
`APPARATUS
`
`Inventors: Mark A. Mehney, Commerce
`Township; Michael C. McCarthy,
`Birmingham; Michael G. Fullerton,
`Ypsilanti; Floyd J. Malecke, South
`Lyon, all of Mich.
`
`Assignee: TRW Inc., Lyndhurst, Ohio
`
`Appl. No.: 09/005,054
`
`Filed:
`
`Jan. 9, 1998
`
`Int. Cl.7 ..................................................... B60R 21/32
`US. Cl.
`........................ 280/735; 73/781; 297/21618
`Field of Search ..................................... 280/734, 735;
`297/2161, 216.18; 73/781, 786; 324/109,
`781
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`5/1955 Gazzo.
`2,708,005
`2/1962 Zia ..................................... 297/21618
`3,022,976
`3,766,344 10/1973 Nevett.
`
`4,075,443
`5,232,243
`5,481,078
`5,502,284
`5,542,493
`5,573,269
`5,739,757
`5,810,392
`
`.
`
`2/1978 Fatur .
`8/1993 Blackburn et a1.
`1/1996 Asche .
`.
`3/1996 Meiller et a1.
`8/1996 Jacobson et a1.
`11/1996 Gentry et a1.
`.
`4/1998 Gioutsos ................................. 280/735
`9/1998 Gagnon ................................... 280/735
`
`.
`
`Primary Examiner—Eric Culbreth
`Attorney, Agent, or Firm—Tarolli, Sundheim, Covell,
`Tummino & Szabo L.L.P.
`
`[57]
`
`ABSTRACT
`
`An apparatus (10) has a vehicle seat frame (30), a weight
`sensor apparatus (22, 22, 22, 22), and a vehicle occupant
`protection device (102) responsive to the weight sensor
`apparatus (22, 22, 22, 22). The seat frame (30) has a bottom
`portion (32) and a back portion (34) which together bear a
`vehicle occupant weight load. A deflectable seat cushion
`(38) covers the bottom portion (32) of the frame (30). The
`weight sensor apparatus (22, 22, 22, 22) measures the entire
`magnitude of the vehicle occupant weight load acting on the
`frame (30) independently of deflection of the cushion (38).
`
`5 Claims, 2 Drawing Sheets
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`AISIN EXHIBIT 1006
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`Page 1
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`AISIN EXHIBIT 1006
`Page 1
`
`

`

`US. Patent
`
`Mar. 21, 2000
`
`Sheet 1 0f 2
`
`6,039,344
`
`
`
`Page 2
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`

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`US. Patent
`
`Mar. 21, 2000
`
`Sheet 2 0f 2
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`6,039,344
`
`
`
`81
`
`82
`
`22
`
`22
`
`STRAIN
`
`GAUGE
`
`ASSEMBLY
` STRAIN
`
`GAUGE
`22
`
`
`ASSEMBLY
`SUMMING
`
`
`AMPLIFIER
`STRAIN
`
`GAUGE
`ASSEMBLY
`
`
`STRAIN
`GAUGE
`22 ASSEMBLY
`
`
`Fig.4
`
`
`
`FLUID SOURCE
`
`Page 3
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`

`

`6,039,344
`
`1
`VEHICLE OCCUPANT WEIGHT SENSOR
`APPARATUS
`FIELD OF THE INVENTION
`
`U\
`
`10
`
`25
`
`The present invention relates to an apparatus for sensing
`the weight of an occupant of a vehicle seat, and particularly
`relates to an apparatus for sensing the weight of the occupant
`and for deploying a vehicle occupant protection device in
`accordance with the weight of the occupant.
`BACKGROUND OF THE INVENTION
`
`US. Pat. No. 5,573,269 discloses an apparatus for sensing
`the weight of a vehicle occupant. The apparatus disclosed in
`the ’269 patent includes an occupant weight sensor which is
`mounted in a vehicle seat. The weight sensor is operatively
`engaged with a deflectable seat cushion, and responds to
`deflection of the cushion under the influence of the weight
`of an occupant of the seat.
`The apparatus disclosed in the ’269 patent further
`includes an inflatable vehicle occupant protection device, a
`source of inflation fluid for inflating the protection device,
`and a controller. When the vehicle experiences a crash, the
`source of inflation fluid is actuated by the controller and
`directs inflation fluid into the protection device to inflate the
`protection device. The controller receives an output signal
`from the weight sensor at the seat cushion, and controls the
`amount of inflation fluid directed into the protection device
`in response to the output signal from the weight sensor. The
`inflation of the protection device is thus controlled in
`accordance with the sensed weight of the occupant of the
`seaL
`
`SUMMARY OF THE INVENTION
`
`35
`
`In accordance with the present invention, an apparatus
`comprises a vehicle seat frame, a weight sensor apparatus,
`and a vehicle occupant protection device responsive to the
`weight sensor apparatus. The seat frame has a bottom
`portion and a back portion which together bear a vehicle
`occupant weight load. A deflectable seat cushion covers the
`bottom portion of the frame. The weight sensor apparatus
`measures the entire magnitude of the vehicle occupant
`weight
`load acting on the seat frame independently of
`deflection of the seat cushion,
`
`In a preferred embodiment of the present invention, the
`apparatus further comprises a track structure which guides
`movement of the seat frame relative to the vehicle floor. The
`weight sensor apparatus is operatively interposed between
`the seat frame and the track structure. Specifically,
`the
`bottom portion of the seat frame comprises a generally
`rectangular seat pan. The frame is mounted on the track
`structure by four deflectable mounting members located
`beneath the four corners of the seat pan. In this arrangement,
`the entire magnitude of the occupant weight load acting on
`the seat frame is transmitted to the floor through the mount-
`ing members and the track assembly. The weight sensor
`apparatus comprises four strain gauge assemblies, each of
`which is operatively engaged with a corresponding one of
`the mounting members. A summing amplifier responds to
`the outputs of the strain gauge assemblies by providing an
`output indicative of the entire magnitude of the vehicle
`occupant weight
`load transmitted through the mounting
`members.
`
`45
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`55
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`60
`
`65
`
`2
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The foregoing and other features of the present invention
`will become apparent to those skilled in the art upon reading
`the following description with reference to the accompany—
`ing drawings, wherein:
`MG. 1 is an exploded View of parts of a preferred
`embodiment of the present invention;
`FIG. 2 is an enlarged, partly sectional view of parts shown
`in FIG. 2;
`FIG. 3 is a partial View of an electrical circuit including
`parts shown in FIG. 2;
`FIG. 4 is a block diagram of parts of the preferred
`embodiment of the present invention; and
`FIG. 5 is another block diagram of parts of the preferred
`embodiment.
`
`DESCRIPTION OF A PREFERRED
`EMBODIMENT
`
`As shown partially in FIG. 1, an apparatus 10 comprising
`a preferred embodiment of the present invention includes a
`vehicle seat 12 and a support structure 14 which supports the
`seat 12 on a vehicle floor 16. The support structure 14
`includes a track assembly 18 for guiding movement of the
`seat 12 relative to the floor 16. The support structure 14
`further includes a plurality of seat mounting members 20
`with corresponding strain gauge circuitry 22.
`The seat 12 has a frame 30 with a bottom portion 32 and
`a back portion 34. The back portion 34 of the frame 30 is
`adjustably supported for inclination relative to the bottom
`portion 32 by a recliner assembly (not shown). Such a
`recliner assembly may be either motorized or manually
`operated, as known in the art.
`Aback cushion 36 covers the back portion 34 of the frame
`30, and a bottom cushion 38 covers the bottom portion 32 of
`the frame 30. Each of the cushions 36 and 38 is a deflectable
`
`structure comprising an outer layer 40 on a compressible
`base 42. The outer layers 40 are preferably formed of fabric
`or leather. The bases 42 are preferably formed of elastomeric
`foam. As further known in the art, the bottom portion 32 of
`the frame 30, which may be referred to as a seat pan,
`includes a wire mesh spring bed 44 (shown schematically)
`for providing resilient support beneath the bottom cushion
`38.
`
`The track assembly 18 defines a pair of parallel tracks 50.
`Each track 50 includes a lower rail 52 (FIG. 2), an upper rail
`54, and a plurality of rollers 56, one of which is shown in
`FIG. 2. The rollers 56 support
`the upper rails 54 for
`longitudinal movement relative to the lower rails 52.
`The support structure 14 preferably has a total of four
`separate mounting members 20. Each mounting member 20
`is located near an end of a corresponding upper rail 54 in the
`track assembly 18. The mounting members 20 are thus
`arranged in a rectangular array, with each mounting member
`20 being located beneath a corresponding corner of the seat
`pan 32.
`As shown in FIG. 2 with reference to one of the mounting
`members 20, each mounting member 20 in the preferred
`embodiment of the present
`invention is a unitary part
`consisting of a single, continuous body of metal such as steel
`
`Page 4
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`

`

`6,039,344
`
`3
`or aluminum. A rigid lower base portion 60 of the mounting
`member 20 is fixed to the corresponding upper rail 54 by a
`fastener 62. A rigid upper base portion 64 of the mounting
`member 20 is fixed to the seat pan 32 by another fastener 66.
`Aliorizontally elongated, flexible intermediate portion 68 of
`the mounting member 20 interconnects the base portions 60
`and 64. The mounting members 20 are thus arranged as
`fixed-fixed or S-type beams that mount the seat pan 32 on
`the upper rails 54. In this arrangement, the support structure
`14, which includes the mounting members 20 and the track
`assembly 18, supports the entire weight of the seat 12 on the
`vehicle floor 16. More specifically, the mounting members
`20 and the track assembly 18 bear the entire weight of the
`seat 12 in series between the seat 12 and the floor 16.
`
`As further shown in FIG. 2, the strain gauge circuitry 22
`on each mounting member 20 preferably comprises an
`assembly of four strain gauges 81, 82, 83 and 84 operatively
`mounted on the flexible portion 68 of the mounting member
`20. The first and second strain gauges 81 and 82 are mounted
`on an upper surface 90 of the flexible portion 68 near its
`opposite ends. The third and fourth strain gauges 83 and 84
`are similarly mounted on a lower surface 92 of the flexible
`portion 68 at locations directly beneath the first and second
`strain gauges 81 and 82.
`When a vehicle occupant sits on the seat 12, an occupant
`weight load is transmitted through the cushions 36 and 38 to
`the frame 30. Since the occupant’s feet normally rest on the
`floor, the occupant weight load acting on the frame 30 is
`normally less than the occupant’s actual weight. However,
`the entire magnitude of the occupant weight load acting on
`the frame 30 is transmitted from the seat pan 32 to the floor
`16 through the mounting members 20 and the track assem—
`bly 18. This causes the flexible portions 68 0f the mounting
`members 20 to bend into S—shaped configurations. The first
`and fourth strain gauges 81 and 84 on each flexible portion
`68 are then placed in compression. The second and third
`strain gauges 82 and 83 are simultaneously placed in ten-
`sion. The two pairs 81, 84 and 82, 83 of strain gauges on
`each mounting member 20 thus respond differently to bend-
`ing of the corresponding flexible portion 68. The four strain
`gauges 81784 on each mounting member 20 are connected
`electrically in a Wheatstone bridge configuration (FIG. 3)
`which develops an output as a function of that difference in
`response. Accordingly,
`the output of each strain gauge
`assembly 22 indicates the amount of bending of the flexible
`portion 68 of the corresponding mounting member 20 under
`the portion of the vehicle occupant weight
`load that
`is
`transmitted through that mounting member 20. The strain
`gauges 81—84 and the circuitry for providing outputs in this
`manner may be of any suitable construction known in the
`art.
`
`Asumming amplifier 94 (FIG. 4) processes the outputs of
`the four strain gauge assemblies 22 to provide an output
`indicating the entire magnitude of the vehicle occupant
`weight load acting on the seat 12. Since the strain gauge
`assemblies 22 are located beneath the four corners of the seat
`
`the output of the summing amplifier 94 in the
`pan 32,
`preferred embodiment of the invention accurately indicates
`the entire magnitude of the vehicle occupant weight load
`regardless of the occupant’s position on the seat 12.
`The output signal of the summing amplifier 94 can be
`used in accordance with the present invention to control
`
`10
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`25
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`35
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`45
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`55
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`6O
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`65
`
`4
`deployment of one or more vehicle occupant protection
`devices. For example, as shown schematically in FIG. 5, the
`summing amplifier 94 is included in a deployment system
`100 with an inflatable vehicle occupant protection device
`102. The deployment system 100 further includes a crash
`sensor 104, a controller 106, and a source 108 of inflation
`fluid. A vent 110 is interposed between the source 108 of
`inflation fluid and the inflatable device 102.
`
`The inflatable device 102 can be any one of several
`different
`types of inflatable vehicle occupant protection
`devices known in the art. Such devices include air bags,
`inflatable seat belts, inflatable knee bolsters, inflatable head
`liners or side curtains, and knee bolsters operated by air
`bags.
`The crash sensor 104 may comprise any known apparatus
`for sensing a vehicle condition that indicates the occurrence
`of a crash. Such a vehicle condition may comprise sudden
`deceleration, crushing of a side portion of the vehicle, a
`vehicle rollover, or the like. If the crash-indicating condition
`is at or above a predetermined threshold level, it indicates
`the occurrence of a crash for which deployment of the
`inflatable device 102 is desired to help protect an occupant
`of the seat 12. The crash sensor 104 then provides a
`deployment signal to the controller 106.
`When the controller 106 receives a deployment signal
`from the crash sensor 104, it responds by actuating the fluid
`source 108 to initiate inflation of the inflatable device 102.
`
`
`
`The controller 106 also responds to the output of the
`Slimming amplifier 94. If the output of the Slimming ampli-
`fier 94 indicates that the weight of the occupant is relatively
`low, the controller 106 causes the vent 100 to direct a firs
`amount of inflation fluid away from the inflatable device
`102. The inflatable device 102 is then deployed in a firs
`mode for protection of a relatively light weight occupant. I i
`the output of the summing amplifier 94 indicates that the
`weight of the occupant is relatively high, the controller 106
`causes the vent 110 to direct a second, lesser amount 0
`inflation fluid away from the inflatable device 102. The
`inflatable device 102 is then deployed in a second, differen
`mode for protection of a heavier occupant.
`In accordance with another
`feature of the presen
`invention, the strain gauge assemblies 22 can be used to
`indicate the position as well as the weight of an occupant o
`the seat 12. For example,
`the outputs of the strain gauge
`assemblies 22 beneath the forward corners of the seat 12 can
`be compared with the outputs of the those beneath the rear
`corners of the seat 12 to determine if the occupant
`is
`out-of—position in a forward direction. A vehicle occupant
`protection device could then be deployed in a mode selected
`for the out-of—position occupant.
`From the above description of the invention, those skilled
`in the art will perceive improvements, changes and modi—
`fications. Such improvements, changes and modifications
`within the skill of the art are intended to be covered by the
`appended claims.
`Having described the invention, the following is claimed:
`1. Apparatus comprising:
`a vehicle seat frame;
`a plurality of deflectable mounting structures which
`together bear the entire weight of said frame;
`
`Page 5
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`

`6,039,344
`
`5
`a plurality of vehicle occupant weight sensor assemblies,
`each of said weight sensor assemblies comprising a
`strain gauge mounted on a corresponding one of said
`deflectable mounting structures; and
`a vehicle occupant protection device responsive to said
`weight sensor assemblies.
`2. Apparatus as defined in claim 1 wherein said deflect—
`able mounting structures support said frame on a track
`structure which guides movement of said frame.
`3. Apparatus as defined in claim 2 further comprising a
`defiectable seat cushion on said frame.
`
`4. Apparatus comprising:
`a vehicle seat frame having a bottom portion and a back
`portion which together bear a vehicle occupant weight
`load;
`a support structure which bears the entire weight of said
`frame and the entire magnitude of said occupant weight
`load, said support structure including a weight sensor
`
`6
`apparatus which measures said entire magnitude of said
`occupant weight load; and
`a vehicle occupant protection device responsive to said
`weight sensor apparatus,
`said support structure including a pair of tracks which
`guide movement of said frame, said weight sensor
`apparatus comprising a plurality of weight sensor
`assemblies which measure portions of said occupant
`weight load acting on said tracks,
`said weight sensor assemblies being operatively inter-
`posed between said frame and said tracks,
`each of said weight sensor assemblies comprising a strain
`gauge mounted on a corresponding deflectable portion
`of said support structure.
`5. Apparatus as defined in claim 4 further comprising a
`defleetable seat cushion covering said bottom portion of said
`frame.
`
`Ln
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`10
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`15
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`Page 6
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`