United States Patent {191
`Protze
`[45] Aug. 25, 1981M
`
`[11]
`
`4,285,545
`
`
`
`[54] AUTOMOBILE PASSENGER SEAT WITH AN
`AUTOMATICALLY POSITIONED
`HEADRFST
`
`[75]
`
`Inventor: Dieter Protze, Wolfsburg, Fed. Rep.
`of Germany
`
`[73] Assignee:
`
`Volkswagenwerk Aktiengesellschaft,
`Wolfsburg, Fed. Rep. of Germany
`[21] App]. No.: 16,545
`
`[22] Filed:
`
`Mar. 1, 1979
`
`Foreign Application Priority Data
`[30]
`Nov. 3, 1978 [DE]
`Fed. Rep. of Germany
`
`2810577
`
`Int. Cl.3 ....................... B6012 21/10; A623 35/00
`[51]
`[52] US. Cl.
`................................. 297/483; 296/65 R;
`-
`297/61; 297/216; 297/410
`[58] Field of Search ................. 297/410. 61, 408, 468,
`297/483, 344, 216, 391; 248/393, 429; 280/808,
`.
`751, 802; 296/65 R
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`2,181,465
`1 1/1939
`Schneider .............................. 297/61
`2,985,229
`5/1961
`..... 297/410
`Shamblin
`
`3,427,073
`2/1969 Downs et a1.
`..
`297/410 X
`3,454,303 ’ 7/1969 Dangwthier
`. 297/410 X
`
`10/1969 Homier et al. ..
`..... 297/410
`3,471,198
`S2011 ............
`.. 297/61
`3,712,666
`1/1973
`
`. 297/408
`3,888,540
`6/1975
`Protz .,.....
`
`3,942,835
`3/1976 Harrison .
`.. 297/61
`3.958.827
`5/1976
`Re‘ ...........
`.. 297/61
`
`4.040.661
`8/1977
`'Hogan et
`...... 297/61
`9/ 1980 Maeda .............................. 297/391 X
`4,222,608
`
`FOREIGN PATENT DOCUMENTS
`
`1/1974 Fed. Rep. of Germany ........... 297/216
`2232726
`2447874 10/1974 Fed. Rep. of Germany .
`2305150 10/ 1976 France ..................................... 297/410
`
`2365985 4/1978 France ............
`. 297/216
`3/1968 United Kingdom ..................... 297/410
`1218541
`Primary Etaminer—James T. McCall
`Attorney, Agent. or Hrm—Brumbaugh, Graves,
`Donahue & Raymond
`
`[57]
`
`ABSTRACT
`
`An automobile driver or passenger seat which is adjust-
`able in the lengthwise direction of the vehicle and has a
`backrest and headrest supported on the backrest and
`vertically adjustable in relation thereto. The position of
`the headrest is adjusted automatically to its optimum
`position in response to the back and forth movement of
`the seat, for moving the headrest upwardly away from
`the backrest when the seat is moved backward, and for
`moving the headrest downwardly when the seat
`is
`moved forwardly. Thus, the headrest will automatically
`be adjusted to the correct height of the passenger occu-
`pying the seat, as he adjusts the position of the seat
`itself. In one form of the invention,
`the adjustment
`mechanism is hydraulic and includes a pair of hydraulic
`cylinders, one cylinder actuated] in response to move-
`ment of the seat, and the other cylinder, attached to the
`headrest, actuated in response to movement of the pis-
`ton in the first piston and cylinder unit. In other forms
`of the invention, mechanical actuating means are shown
`and described.
`
`20 Claims, 6 Drawing Figures
`
`
`
`Page 1 of 10
`
`Hyundai Exhibit 1004
`
`Page 1 of 10
`
`Hyundai Exhibit 1004
`
`

`

`U.S. Patent
`
`Aug. 25, 1981
`
`Sheet 1 of 3
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`4,285,545
`
`
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`Page 2 of 10
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`Page 2 of 10
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`

`

`US. Patent
`
`Aug. 25, 1931
`
`Sheet 2 of3
`
`4,285,545
`
`
`
`Page 3 of 10
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`Page 3 of 10
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`

`

`U.S. Patent
`
`Aug. 25, 1981
`
`Sheet 3 of3
`
`4,285,545
`
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`Page 4 of 10
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`Page 4 of 10
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`1
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`4,285,545
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`2
`mechanism may be provided with a step down from the
`relative motion of the seat.
`
`According to the invention, the means for adjusting
`the height of the headrest according to the lengthwise
`adjustment of the seat may be hydraulic, mechanical, or
`electronic in nature.
`‘
`In one form of the invention, a first hydraulic cylin-
`der is connected between the backrest of the seat and
`headrest to move it between positions, and a second
`hydraulic cylinder is attached between the seat and the
`vehicle floor so that the piston is actuated in response to
`movement of the seat back and forth. The hydraulic
`pressure chambers of the two piston and cylinder units,
`on either side of the piston in each, are connected by a
`pair of hydraulic lines, the lines connecting each pres-
`sure chamber of the cylinder so that upon actuation of
`the piston of the second piston cylinder unit, the piston
`of the first cylinder unit will thereby be actuated to
`move the headrest up or down depending upon which
`way the seat is moved. A valve means may be inter-
`posed in the hydraulic lines which except upon manual
`actuation will prevent inadvertent movement of the seat
`and the headrest. In a varied form, hydraulic fluid may
`be supplied under pressure to the hydraulic lines, within
`an appropriate valving arrangement to control automat-
`ically the piston and the cylinder movements to move
`the seat and headrest to a desired position.
`In another form of the invention, a connecting mem-
`ber capable of transmitting tensile and compressive
`forces may be coupled to the headrest at one end and
`the vehicle body at its other end to move the headrest in
`accordance with seat movement. One such member
`may be a sheathed cable, the sheath of which is fixedly
`attached to the vehicle seat at one end and a fixed mem-
`ber on the seat backrest at its other end. The cable
`movable inside the sheath is attached at one end to a
`cross-support attached to a pair of sliding members for
`moving the backrest up and down, and attached at its
`other end to a fixed portion of the vehicle.
`In another form of the invention, a pulley and cable
`arrangement, the cables attached between the vehicle
`body and the backrest and headrest, may be provided to
`move the headrest in response to back and forth move-
`ment of the seat. Finally,
`in another mechanical ar-
`rangement, a rack and pinion is employed,
`the rack
`coupled to the headrest, and the pinion coupled to a
`transmission, in turn actuated by movement of the seat
`longitudinally along the vehicle. In either the cable
`arrangement or rack and pinion arrangement, a servo-
`mechanism may be coupled for automatically actuating
`the adjustment mechanism attached between the vehi-
`cle floor and the headrest to move the seat back and
`forth and at the same time adjust the headrest.
`Also, in the case of the sheathed cable, cable or pinion
`arrangement, step down gearing or motion is provided
`so that the relative length of vertical travel of the head-
`rest is about half that of the longitudinal travel of the
`seat. If desired, one end of the shoulder belt, or a belt
`take up mechanism, may be attached to the side of the
`headrest. In such an arrangement, the shoulder articula-
`tion of the belt will vary in accordance with the height
`of the headrest, and thereby also vary‘with respect to
`the shoulder height of the driver or passenger.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`Fora better understanding of the invention, reference
`may be had to the following detailed description of
`
`AUTOMOBILE PASSENGER SEAT WITH AN
`AUTOMATICALLY POSITIONED HEADREST
`
`BACKGROUND OF THE INVENTION
`
`The invention relates to a passenger seat for a motor
`vehicle which is adjustable in the lengthwise direction
`of the vehicle and includes a‘ backrest with a head sup—
`port supported vertically thereon and adjustable with
`respect thereto.
`Headrests attached to the backrest of a passenger
`vehicle seat provide optimum protection for passengers,
`in the case of an accident, when they are positioned at a
`level even with the head of the passenger or driver.
`Since vehicle occupants will vary in height, the head-
`rest must be individually adjusted according to the
`height of the passenger or driver, raised for taller per-
`sons and lowered for shorter passengers. Vehicle pas-
`sengers, however, often do not bother to adjust the
`height of the headrest because it is inconvenient, so that
`as a practical matter the headrests are rarely at the right
`level. The result of this is that in an accident, passengers
`run the risk of sustaining severe injuries, in particular to
`the neck vertebrae, due to the fact that maladjusted
`headrests will not offer protection.
`SUMMARY OF THE INVENTION
`
`In accordance with the present invention, an automo-
`bile passenger seat includes a headrest vertically and
`adjustably supported on the backrest of the seat, which
`is automatically adjusted to the individual height of
`each driver or passenger thereby to adjust the headrest
`individually to the proper height in each case.
`More particularly,
`in accordance with the present
`invention, means are provided for automatically adjust-
`ing the height of the headrest in response to changes in
`the longitudinal position of the passenger seat so that
`the headrest will be moved upwardly when the seat is
`shifted back, and will be lowered when the seat is
`shifted forward. This'will provide a proper automatic
`adjustment of the headrest due to the relationship be-
`tween the proper headrest level of a driver or passenger
`and the seat adjustment he will select according to his
`height. For example, a very short passenger or driver
`will move the seat forward as far as possible in the
`lengthwise direction of the vehicle for comfort and to
`have the steering wheel and switches and knobs on the
`instrument board within easy reach, as well as being
`able to reach the gas pedal, brake, and clutch pedal (if
`any) of the vehicle with his feet. A rather tall driver or
`passenger, with a correspondingly high head level, will
`normally move the seat as far back as he can for the sake
`of comfort or for room to place his legs in position to
`operate the foot pedals. The two extreme seat positions
`will thus be associated with the highest and lowest
`headrest settings; namely, with the seat moved as far
`forward as possible for a short person the headrest
`would be at its lowest setting, and for the seat moved as
`far back as space permits for a taller person, the head-
`rest would move to its highest position. Correspond-
`ingly,
`for
`intermediate seat positions,
`the headrest
`would likewise be moved to an intermediate height.
`Typically, the preferred length of travel of the head-
`rest between its highest and lowest position is about half
`the lengthwise travel of the seat between its extreme.
`back and forth positions so that the headrest adjusting
`
`5
`
`10
`
`15
`
`20
`
`25
`
`3O
`
`35
`
`40
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`45
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`50
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`55
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`60
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`65_
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`Page 5 of 10
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`4
`pressure chamber on either side of the piston 31. A
`piston rod 14 is attached at one end to the piston 31 and
`coupled at its outer end 16 to the headrest 5. Preferably
`the headrest 5 is connected to a pair of sliding rods 17
`which'are guided in the backrest 4. The slides 17 have
`a cross support member 45, to which the other end 16 of
`the piston rod 14 is attached.
`A second piston and cylinder unit has a cylinder 18
`attached at one end 22 to the frame of the seat 3 and a
`piston 30 and piston rod 19 attached at its outer end 20
`to a lug 21 fastened to the floor 111 of the vehicle. The
`piston 30 in the second piston and cylinder unit likewise
`is capable of being acted upon on either side by pressure
`in one of the hydraulic pressure chambers in the cylin-
`der 18.
`
`The remaining seat design shown in FIG. 1 is that of
`a so-called three-legged seat, in which the seat is sup-
`ported on a pair of rear side legs 11 in tracks 12 fastened
`to the floor la of the vehicle, and by a center front slide
`on the seat receiving a lug 10 affixed on the vehicle
`floor la.
`The hydraulic adjusting system is further shown in
`FIG. 2. The first piston and cylinder unit 13, 14, 31 and
`the second piston and cylinder unit 18, 19, 30 have a pair
`of hydraulic lines 28 and 29 interconnecting the two
`pressure chambers of the pistons 30 and 31. A valve
`arrangement 23 is interposed in the hydraulic lines 28
`and 29 for shutting off the lines 28 and 29 when in the
`rest position, to prevent inadvertent movement of the
`seat 3 and headrest 5. A handle 24 pivoted on a lug 25
`underneath the seat frame 3 of the passenger seat 2 may
`be provided for opening the valves 26 and 27 to permit
`the seat to be adjusted.
`With the valves in their closed position, the hydraulic
`fluid present in the pressure chambers of the cylinders
`13 and 18 and in the hydraulic lines 28 and 29, being
`incompressible, provides a force acting against move-
`ment in either direction of the seat and thus will prevent
`seat movement. When the valves 26 and 27 are opened
`by actuating the lever 24, the seat may be adjusted
`forward or back at will by the occupant. Movement of
`the seat in either direction will cause the cylinder 18 to
`move with respect to the piston 30 of the second piston
`and cylinder unit. This will force hydraulic fluid out of
`one pressure chamber of the cylinder 18 and through
`one of the hydraulic lines 28 or 29 into the correspond-
`ing pressure chamber of the first piston and cylinder
`unit. This, in turn, will cause the piston 31 in the first
`piston and cylinder unit to move, forcing hydraulic
`fluid out through the other hydraulic line and back into
`the other pressure chamber of the second piston and
`cylinder unit. The position of the two piston and Cylin-
`der units as shown in FIG. 2 corresponds to the forward
`position of the seat (indicated 'by the dotted lines of
`FIG. 1). Thus, by actuation of the lever 24 the seat
`could then be pushed backward. This would force hy-
`draulic fluid out of the pressure chamber of cylinder 18
`and through line 28 into the pressure chamber of cylin-
`der 13 on the lower side of the piston 31 in the first
`piston and cylinder unit. As the piston 31 is forced up-
`ward, hydraulic fluid would be forced from the other
`side of cylinder 13 out through the hydraulic line 29 and
`back into the other side of the cylinder 18 to the right of
`piston 30 in the second piston and cylinder unit.
`In accordance with a preferred embodiment of the
`invention,
`the face area of the piston 31 of the first
`piston and cylinder and is about twice as large as the
`piston area of the piston 30 of the second piston and
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`4O
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4,285,545
`
`3
`preferred embodiments, taken in conjunction with the
`accompanying drawings, in which:
`FIG. 1 is a side view of a longitudinally adjustable
`automobile driver seat installed in a vehicle and having
`a vertically adjustable headrest;
`FIG. 2 is a schematic representation of a hydraulic
`apparatus for adjusting the headrest according to the
`lengthwise adjustment of the seat;
`FIG. 3 is a schematic representatic‘m of a hydraulic
`adjusting apparatus having a pressure delivery system
`for power adjustment of the seat and headrest;
`FIG. 4 is a pictorial representation of a passenger seat
`having a mechanical adjusting arrangement including a
`connecting member capable of transmitting tensile as
`well as compressive forces, for adjusting the headrest in
`response to the lengthwise adjustment of the seat;
`FIG. 5 is a pictorial view of another form of mechani-
`cal adjustment for adjusting the headrest in response to
`adjustment of the position of the seat and having a pair
`of cooperating cables actuatable in opposite directions;
`and
`
`FIG. 6 is a pictorial representation of another em-
`bodiment of a passenger seat having a mechanical ad-
`justing arrangement including a rack and pinion gear
`arrangement and a transmission operable in response to
`movement of the seat and coupled to the pinion.
`DETAILED DESCRIPTION OF PREFERRED
`EMBODIMENTS
`
`Referring to FIG. 1 of the drawings, a passenger or
`driver seat 2 is installed in a passenger motor vehicle 1,
`and is adjustable in the lengthwise direction of the vehi-
`cle. The seat has a frame 3 and a backrest 4 which may
`be pivotable. A headrest 5 is supported on the backrest
`4 and vertically adjustable in relation thereto.
`As shown in FIG. 1, the solid line represents the seat
`in its extreme rear position, as would be required for a
`relatively tall person 6a, and the dotted line configura-
`tion represents the seat 3 moved to its extreme forward
`position for a shorter passenger 6b. Corresponding with
`the forward and rearmost positions of the passenger seat
`2, the corresponding extreme vertical positions of the
`headrest 5 are shown in solid and dotted lines, as in its
`highest position when the seat 3 is in the rearmost seat
`position, and in its lowest position when the seat
`is
`moved forward.
`A conventional shoulder safety belt 7 is also shown in
`FIG. 1, which is designed to extend diagonally across
`the body of the passenger. The belt has an articulation
`point 9 on the side of the headrest 5, and is attached to
`a retraction system 8 in the roof of the vehicle. Alterna-
`tively, the retraction system may instead be mounted
`directly on the headrest 5 (see FIGS. 5 and 6). In either
`case, the articulation of the shoulder end of the belt at
`the headrest 5 results in automatic adjustment of the
`safety belt depending upon the height of the passenger,
`since the position of the articulation point 9 will change
`with the adjustment of the seat 3 and thereby headrest.
`Thus the belt will always be located at the optimum
`position to extend across the passenger without it be-
`coming an encumbrance or a hazard.
`In accordance with the form of the invention shown
`in FIG. 1, the adjustment of the headrest relative to the
`adjustment of the seat occurs using a hydraulic arrange-
`ment. A first piston and cylinder unit has a cylinder .13
`attached at one end to the backrest 4 and a piston 31
`(FIG. 2) capable of being moved back and forth within
`the cylinder 13 in response to a force in the hydraulic
`
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`4,285,545
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`5
`cylinder unit. If the piston 30, therefore, is displaced a
`certain distance in the cylinder 18, piston 31 will travel
`approximately half as far in cylinder 13. The headrest 5
`connected to the outer end 16 of piston rod 14 of the
`first piston and cylinder unit would thereby be moved,
`relative to the backrest 4, a distance half as far as the
`length~wise displacement, relative to the floor, of the
`seat 3.
`.
`
`6
`the incompressibility of the hydraulic fluid in the lines
`28a, 28b, and 29. Thus the seat will remain fixed. If the
`occupant desires to move the seat forward (and thus the
`headrest dovm), the valve lever 24’ is moved towards
`the right, thus opening the valve 27’, and connecting
`line 28b from the first piston and cylinder unit with the
`line 40 leading to the supply tank 41. This will eliminate
`the fluid under pressure in line 35 to move through
`hydraulic line 28a and force piston 30 towards this right
`hand position,
`forcing in turn hydraulic fluid out
`through the line 29a into the cylinder 13, and moving
`the piston 31 downward. Thus the occupant, simply by
`manipulation of the lever 24’ can move the seat back
`and forth as he prefers, and at the same time a corre-
`sponding vertical adjustment of the headrest in accor-
`dance with the particular seat position will occur auto-
`matically.
`Referring to FIG. 4, a passenger seat is shown in
`which the adjustment of the headrest in response to
`movement of the vehicle seat is by a mechanical ar-
`rangement. The arrangement
`includes a connecting
`member 46 capable of transmitting forces in tension and
`compression. One end 47 of the connecting member 46
`is attached to a cross-piece 45 arranged between the
`two slide rods 17 of the headrest 5. The other end 48 of
`the member 47 is attached to a swinging lever 49 piv-
`oted between an arm 20 articulated on a center lug 10
`attached to the vehicle body la and a lug 50 attached to
`the seat frame 3. This connecting member 46 may, for
`instance, be a sheathed cable, for example a Teleflex
`element, designed to transmit the moving force of the
`lever 49 to the cross member 45. As thus shown, when
`the seat 2 is moved forward, the lever 49 pivots on lug
`50, and moves the attachment point 48 of the cable of
`the connecting member toward the fixed attachment
`point 51 of the sheath fixed on the seat frame 3. The
`cable of the connecting member 46 will thus be forced
`out the same distance from the other end of the sheath
`and move the cross member 45 and thus the headrest 5
`downward. The lever 49, however, due to the articula-
`tion arrangement, serves to decrease by one-half the
`travel distance the headrest relative to the forward or
`rearward travel of the seat. FIG. 4 does not specifically
`show an arrangement for locking the seat and headrest,
`once adjusted, in position, but this may be done in a
`conventional manner.
`
`FIG. 5 shows another mechanical adjusting arrange-
`ment for the headrest 5 responsive to movement of the
`seat 2 back and forth. This arrangement consists essen-
`tially of two opposed cable arrangements 55 and 60.
`The cables 55, 60 are essentially guided on the backrest
`4 and one of the slide legs 11 of the seat, with their ends
`being connected to the floor of the vehicle forward and
`behind the leg 11, respectively. Their other ends are
`attached to the cross support 45 attached to the headrest
`5. One end 56 of a cable 55 is attached to the floor of the
`vehicle in front of the guide rail 12 in the longitudinal
`direction of the vehicle. The cable 55 extends around a
`pulley 570 on the leg 11 of the seat 2 to the backrest 4
`and around another pulley 57b to the cross support 45
`from above. The cable is attached to the crosssupport
`45 by a pulley 58, and thereafter its free end 59 is at-
`tached to a cross piece 65 fixed on the backrest above
`the cross support 45, thus forming a block and tackle
`arrangement. The other cable 60 is fastened to the floor
`at one end 61 behind the guide rail, and thereafter ex—
`tends over a pulley 62a on the leg 11 to a pulley 62b on
`the backrest 4. Thereafter, this cable is also rigged in a
`
`Referring to FIG. 2, a compensator 32 is connected
`to the hydraulic lines 28, 29 to accommodate an expan-
`sion or contraction of hydraulic fluid in the system as
`would occur, for example, by changes in temperature.
`The compensator consists of a piston 33 in the cylinder
`32 which is biased by a spring 34. The piston 33 will
`thus yield elastically without damage to the adjusting
`system in the case of the expansion of the hydraulic
`fluid.
`
`10
`
`15
`
`FIG. 3 represents an alternative form of hydraulic
`adjusting system, in which a power adjustment is in-
`cluded for adjusting the seats and headrests. A reservoir
`36 is connected to one of the hydraulic fluid lines, e.g.
`28:1, by a line 35. The reservoir 35 is supplied from a
`tank 41 by a pump 37. An excess pressure valve arrange-
`ment 38 is interposed between the pump 37 and reser-
`voir 36 to provide a return line opening at a predeter-
`mined maximum pressure on the pressure side of the
`pump, which would return fluid to the suction side of
`the pump. Thus a maximum pressure limitation will be
`provided on the pressure side of the pump and also in
`the reservoir 36 and the system of lines 35 and 28a
`connected to it.
`‘
`A modified form of valve arrangement 23’ suitable
`for this power operated system is shown in FIG. 3 and
`may be fixed underneath frame 3 of the seat 2 much like
`the valve means 23 in FIG. 21. Handle 24' is connected
`to the valve arrangement 23’ and has 3 positions: in a
`first position line 280 is connected to line 28b; in a sec-
`ond position the connection between 28a and 28b is
`interrupted; and in the third position line 28b, leading to
`the first piston and cylinder unit 13, 14, 31, is connected
`to a line 40 leading to the supply tank 41, which would
`be under atmospheric pressure.
`The lever 24’ in the valve 23‘ provides an automatic
`power adjustment of the seat position and thus the head-
`rest position. In the intermediate position the lever,
`shown in FIG. 3, the seat is locked in position, since no
`hydraulic fluid can move in either direction between
`the first and second piston and cylinder unit. When the
`lever 24’ is moved towards the left, the pressure deliv-
`ery system 35, 26, 37 is connected to line 28b, and will
`force fluid into the lower side of the cylinder 13
`through line 28b to move the piston 31 upward as ori-
`ented in FIG. 2. This will consequently cause the cylin-
`der 18 to move towards the right, and will force the seat
`backward. This occurs, even though the fluid pressure
`is as great in line 28a as it is in 28b, since the cross sec-
`tional area of the piston 31 is twice as large as that of the
`piston 30. Thus the force on the piston 31 will exceed
`that on the piston 30, causing the piston 30 to move
`upward in the first piston and cylinder unit 31 to force
`hydraulic fluid out through the line 29a and into the
`piston 18, thereby moving the piston 30 towards the
`left.
`
`Once the seat has been moved into the desired posi-
`tion, the occupant can move the lever 24' back to its
`middle position where the two lines 280 and 2817 are
`disconnected by the closed valve 26'. This will lock the
`seat and headrest into the selected position, because of
`
`20
`
`25
`
`30
`
`35
`
`4O
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`45
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`50
`
`55
`
`60
`
`65
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`7
`block and tackle arrangement over a pulley 63 on the
`moveable cross support 45 with its free end 64 attached
`to another cross piece 66 of the backrest 4 below the
`cross piece 45. The block and tackle rigging of the
`cables 55 and 60 serves to halve the travel distance of
`the headrest relative to the travel of the seat 2. As can
`be seen, however, adjustment of the seat by the passen—
`ger automatically adjusts the position of the headrest to
`the level corresponding to the particular seat position.
`In the embodiment shown in FIG. 5, once again a look-
`ing arrangement for the seat once it is in a desired posi-
`tion is not specifically shown. Such conventional mech-
`anisms are known, however.
`FIG. 6 shows another mechanical adjusting arrange-
`ment for adjusting the position of they headrest 5 in
`response to movement back and forth of the passenger
`seat. In this case, the adjustment mechanism for moving
`the headrest 5 is a rack and pinion arrangement 70, 71.
`A rack is attached to the cross support 45 connected to
`the headrest 5 and meshes with the pinion 71. The pin-
`ion 71 is fixed on a shaft 72 mounted on the backrest 4,
`which in turn is driven by a transmission consisting of
`two gears 73, 75 and a gear belt or chain 74 between the
`two gears. The lower gear 75 in turn is coupled to a
`cable wheel 76 driven by a cable 77. The two ends 78
`and 79 of the cable 77 are fastened to the floor in front
`and behind the guide rail 12, so the cable 77 extends in
`the longitudinal direction of the vehicle. The cable 77 is
`passed over pulleys 80 on the side leg 11 of the seat 2
`and thereafter over the cable wheel 76. When the seat 2
`is moved in the lengthwise direction of the vehicle, the
`cable 77 will rotate the wheel 76, which in turn will
`actuate the transmission 75, 73, and thus the pinion 71.
`Therefore, as the seat is moved back and forth,
`the
`headrest 5 will likewise move up and down. The trans-
`mission gears as well as the rack and pinion are designed
`and sized so that the headrest 5 again will travel about
`half as far as the passenger seat, so that again the head-
`rest will assume automatically the optimum position
`relative to the driver or passenger’s head in response to
`the movement of the seat.
`In FIG. 6, a servomotor 81 is also shown which is
`capable of actuating the cable wheel 76 or cable 77 in
`either selected direction. When such a servomechanism
`is provided, the seat can be adjusted automatically, that
`is by a power adjustment, and at the same time would
`look the seat in position when not actuated. As is appar-
`ent, a servomoter could also be supplied in connection
`with the embodiment shown in FIG. 5. FIGS. 5 and 6
`also show a retraction system 8’ of a diagonal shoulder
`strap 7 mounted on a side of the headrest 5. This, of
`course, requires that the backrest is rigid enough to
`withstand the restraining forces acting on the belt in the
`case of an accident.
`Although the invention has been shown and de-
`scribed with reference to certain preferred embodi-
`ments thereof, it will be understood that variations and
`modifications will be apparent to those skilled in the art
`while not departing from the inventive principles dis-
`closed herein. All such variations and modifications are
`intended to be within the scope of the present invention,
`as defined in the following claims.
`I claim:
`1. In an automobile driver or passenger seat, said seat
`adjustable in the lengthwise direction of the vehicle and
`having a backrest, and a headrest supported on said
`backrest and vertically adjustable in relation thereto,
`the improvement comprising means for adjusting auto—
`
`5
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`6O
`
`65
`
`4,285,545
`
`8
`matically the position of said headrest in response to
`lengthwise movement of said seat for moving said head—
`rest upwardly away from said backrest when said seat is
`moved backward, and for moving said headrest down—
`wardly when said seat is moved forward.
`2. An automobile seat according to claim 1, wherein
`said means for automatic adjustment are adapted so that
`the length of travel of said headrest is about half the
`corresponding length of travel of said seat for any given
`longitudinal distance of movement of said seat.
`3. An automobile seat according to claim 1 or 2,
`wherein said means for automatic adjustment of the
`headrest comprise hydraulic means.
`4. An automobile seat according to claim 3, wherein
`said hydraulic means comprises a first cylinder and
`piston unit connected between said headrest and said
`backrest, a second piston and cylinder unit connected
`between said seat and the floor of the vehicle, said pis-
`ton of each said piston and cylinder units dividing said
`cylinder into a first and second hydraulic pressure
`chamber, a first hydraulic line connected between said
`first hydraulic pressure chambers, and a second hydrau-
`lic line connected between said second hydraulic pres-
`sure chambers, and a valve means in said first hydraulic
`line for controlling the flow through said hydraulic
`lines and thereby to prevent inadvertent movement of
`the seat when said valve is closed interrupting said first
`line.
`5. An automobile seat according to claim 4, further
`comprising a valve means in said second hydraulic line.
`6. An automobile seat according to claim 4, wherein
`said valve means is manually actuatable,
`thereby to
`permit lengthwise adjustment of said seat.
`7. An automobile seat according to claim 6, wherein
`one of said hydraulic lines communicates with a com-
`pensator means for enlarging the overall hydraulic vol-
`ume in said hydraulic means for compensating for
`changes in the hydraulic fluid volume.
`8. An automobile seat according to claim 7, wherein
`the piston associated with said first piston and cylinder
`unit has about double the cross-sectional area of the
`piston associated with said second piston and cylinder
`unit,
`the piston associated with said first piston and
`cylinder unit thereby having about half a relative length
`of travel with respect to a corresponding length of
`travel of the piston associated with said second piston
`and cylinder unit.
`9. An automobile seat according to claim 4, wherein
`in said hydraulic means comprises a pressure delivery
`means for providing hydraulic fluid under pressure, and
`means for automatically adjusting said seat and said
`headrest.
`10. An automobile seat according to claim 9, wherein
`said pressure delivery means comprises a pressure reser—
`voir connected to said first hydraulic line and a pump
`means for providing hydraulic fluid under pressure to
`said reservoir, said pump means including delivery pres-
`sure limiting means for limiting the pressure of said
`hydraulic fluid delivered from said pump.
`11. An automobile seat according to claim 10,
`wherein said pressure reservoir is connected between
`said valve means and said second piston and cylinder
`unit.
`
`12. An automobile seat according to claim 11,
`wherein said valve means has a first position adapted for
`connecting said pressure reservoir through said first
`hydraulic line with both said first piston and cylinder
`unit and said second piston and cylinder unit, a second
`
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`position adapted to interrupt said first hydraulic line,
`and a third position adapted to connect said first piston
`and cylinder unit through said first hydraulic line to
`atmosphere.
`13. An automobile seat according to claim 1 or 2,
`wherein said means for adjusting said headrest comprise
`mechanical means.
`
`14. An automobile seat according to claim 13,
`wherein said mechanical means comprises a connecting
`member capable of transmitting compression and ten-
`sion forces and coupled between said vehicle body and
`said headrest.
`15. An automobile seat according to claim 13,
`wherein said headrest is supported by a pair of slide
`rods, said slide rods having a cross-support member
`therebetween, said seat is supported on a pair of seat
`legs adjustable lengthwise of said vehicle, and wherein
`said mechanical means comprises a first cable attached
`at one end in front of one of said seat legs and at its other
`end to said cross-support, a second cable attached at one
`end behind said seat leg and at its other end to said
`cross-support, and guide means on said seat for guiding
`said first and second cables