Automatic fold and return head restraint

[0001] This invention relates to vehicle seats and more particularly headrests.

[0002] Most vehicles have one, two or three rows of vehicle seats for the driver and passengers. In some motor vehicles such as minivans and sport utility vehicles, a storage area is located behind the last row of seats. In order to access rows of seats or the storage area, at the back of the vehicle, vehicle seats often fold forward to allow easier access or to increase the size of the storage area.

[0003] When folded forward, the headrest for the vehicle seat over strikes the dashboard or the seat immediately before it. The contact of the headrest with the seat or dashboard creates several problems. First, the seat never becomes fully folded, thus limiting the amount of space available to a passenger to enter a rear seat. Second, when the seat is initially folded, the headrest may violently come into contact with the dashboard, potentially causing damage to the dashboard or the headrest. Third, after the seat is folded, the headrest may be forced into the dashboard as the passenger enters the rear seat, again potentially damaging the dashboard or the headrest, or both.

[0004] To address this problem, some vehicle seats can be slid backward to allow the seat to fully fold. However, the user must manually move the seat backward, and, if the storage area has been loaded with cargo prior to folding down the seat, the cargo must be moved. This results in inconvenience to the user as to both time and effort in using the storage area.

[0005] Other seats use a headrest retractable into the seatback. While such a seatback/headrest combination does allow the seatback to be fully folded forward without moving the seat, additional problems arise. The seatback has to be substantially modified to accommodate the headrest. The cavity within the seat for the headrest may structurally weaken the seat, creating a potential risk to passengers. Finally, because a significant portion of the upper part of the seat is dedicated to the cavity for the headrest, ergonomic design of the seat is further complicated, requiring a complex design to supply padding and appropriate passenger support.

[0006] A headrest which allows the seat to be fully folded forward without requiring additional effort by the user and which does not require extensive modifications to the seat is desirable.

[0007] The headrest and seat described herein allow the placement of the seatback into a full folded position. As the seatback is rotated forward, the headrest pivots from an extended position into a stowed position, thus avoiding contact with the preceding seat or the dashboard.

[0008] The headrest includes a mounting bracket and a rotational shaft. The mounting bracket is attached to the seatback, while the rotation shaft is mounted within the mounting bracket. A cable is attached to the headrest and the seat or the motor vehicle. As the seatback is rotated forward, the headrest pivots into the stowed position. A lock to prevent motion of the headrest when the seatback is in the upright position is provided. A clutch, circumferentially mounted about the rotation shaft, controls the engagement of the lock with the headrest. Upon rotation of the seatback, the clutch disengages the lock from the headrest. Additional rotation of the seatback causes the headrest to reach a stowed position.

[0009] Such a seat and headrest provides significant advantages. First, the mechanism for pivoting the headrest is contained substantially within the headrest. No significant modification of the seatback is required. Second, seatbacks currently used in motor vehicles could use the headrest with only minor modifications. Current seats could be retrofitted with little problem with the headrest. Finally, the headrest is automatically stowed as the seatback is rotated forward. A user is not required to perform any additional tasks.

[0010] These and other objects, advantages and features of the invention will be more readily understood and appreciated by reference to the detailed description of the drawings.

[0027] FIG. 1 shows a motor vehicle 10 with seats 12,14. Rear seat 12 has seat pan 16, seatback 18, and headrest 20 Rear seat 12 is in an upright position. A storage area is located behind seat 12. As shown in FIG. 1, headrest 20 is in the extended position.

[0028] FIG. 2 shows motor vehicle 10 rear seat 12 in the fully folded position. Seatback 18 is moveable. As seatback 18 is rotated to the fully folded position 21, headrest 20 also rotates forward. When seatback 18 is in the fully folded position 21, headrest 20 has been rotated such that the headrest tucks between the front of seat pan 16 and the back of front seat 14. The headrest 20 could rotate at least seventy degrees or at least 100 hundred degrees, depending upon the specific requirements for rear seat 12, front seat 14, and headrest 20. Headrest 20 in FIG. 2 is shown in the stowed position.

[0029] When seatback 18 is between the full upright position 19 and the fully folded position 21, it is in the partially folded position 23. Headrest 20 is then in a partially stowed position. Seatback 18 moves a seatback distance through a seatback rotational angle along seatback arc 23.

[0030] When the rear seat 12 is fully folded forward, the storage area is thus significantly expanded. Since the headrest 20 has been stored between the back of front seat 14 and the front of seat pan 16, headrest 20 is protected from damage by any cargo loaded into the storage area. Further, cargo laid on the back of rear seat 12 will not force headrest 20 into either the back of front seat 14 or the floor of the motor vehicle, thus preserving headrest 20.

[0031] FIG. 3 shows a headrest mechanism 30. Headrest mechanism 30 is contained substantially within seat back 18. Mounting bracket 32 is U-shaped and contains rotation bracket 34. Headrest prongs 31 are likewise attached to rotation bracket 34.

[0032] Rotatable shaft 36 is fixedly attached to rotation bracket 34, and extends through the first side of mounting bracket 32, allowing rotation bracket 34 to move relative to mounting bracket 32. Clutch 38 is circumferentially positioned around rotatable shaft 36. Clutch 38 is substantially cylindrical, and contains cam 40. Since clutch 38 is substantially cylindrical, it has a clutch axis. Cam 40 traverses clutch 38 at an angle with the clutch axis.

[0033] Pin 42 extends axially from rotatable shaft 36, and rests within cam 40. Bun 33 thus is pivotal about an axis defined by rotatable shaft 36.

[0034] Lock 44 is juxtaposed with cam 40 and with the second side of mounting bracket 32. Hook 39 of clutch 38 latches to lock 44. As clutch 38 is rotated, the force of pin 42 on cam 40 causes clutch 38 to translate longitudinally along rotatable shaft 36. Lock 44 similarly moves along rotatable shaft 36.

[0035] Spring 46 is placed at least partially about rotatable shaft 36. First spring end 48 of spring 46 is connected to stop 50. Second spring end 52 is connected to lever arm 54 of clutch 38. Spring 46 keeps clutch 38 biased against lock 44 by applying a force on lever arm 54, causing cam 40, to exert a force on pin 42, thereby moving clutch 38 toward lock 44. The force applied by clutch 38 to lock 44 also biases lock 44 into the second side of mounting bracket 32. Cable 56 is attached at one end to clutch 38. Cable 56 is attached at its other end to any point which moves relative to seat back 18 and headrest 20. One suitable attachment point for the other end of cable 56 would be seat pan 16. Cable 56 would have a fixed length.

[0036] FIG. 4 is an exploded view of headrest mechanism 30. Mounting bracket 32 has first mounting bracket side 60 and second mounting bracket side 62.

[0037] Rotatable shaft 36 rests within first rotation bracket hole 62 and second rotation bracket hole 64. Rotatable shaft 36 is secured to rotation bracket 34 by, for example, welding.

[0038] Mounting bracket 32 has a first mounting bracket plate 66 and a second mounting bracket plate 68. First bushing 70 resides within first mounting bracket hole 72. Rotatable shaft 36 extends through first mounting bracket hole 72.

[0039] Spring 46 resides around rotatable shaft 36. A portion of pin 42 is placed within hole 74. Pin 42 also extends axially from either side of rotatable shaft 36. Slot 76 extends longitudinally along a first end of rotatable shaft 36. Clutch 38 rests around rotatable shaft 36. Clutch 38 has latch 75. Latch 39 attaches to a lip in lock 44, allowing clutch 38 to pull lock 44. Lock 44 and clutch 38 are juxtaposed and slide upon rotatable shaft 36. Clutch 38 has first cam 40 and second cam 77. Pin 42 extends into first cam 40 and second cam 77. Lock 44 has button 79.

[0040] Cable 56 surrounds and is affixed to clutch 38. Cross-member 78 of lock 44 moveably resides within slot 76 of rotatable shaft 36. A second end of rotatable shaft 36 extends through second mounting bracket hole 80 and bushing 82. Button 79 may extend through button aperture 84, depending upon the position of the lock 44 relative to second mounting bracket plate 68.

[0041] FIGS. 5–13 show headrest mechanism 30 and illustrate the operation of headrest mechanism 30.

[0042] FIGS. 5–7 show headrest mechanism 30 in the locked position. Headrest 20 would thus be in the extended position. Button 79 is shown extending through mounting bracket 32. Pin 42 of clutch 38 is in a first pin position in first cam 40. Pin 42 is distal from lock 44 in first cam 40. FIG. 6 shows a side perspective of a portion of headrest mechanism 30 with clutch 38, first cam 40, pin 42, lock 44 and button 79 in the same position as is shown in FIG. 5.

[0043] As shown in FIG. 7, cross-member 78 of lock 44 is shown riding within slot 76 of rotatable shaft 36. Cable 56 circumnavigates clutch 38 and is attached to clutch 38 at stay 86.

[0044] FIGS. 8–10 show the headrest mechanism 30 in the unlocked position, but prior to movement of rotation bracket 34. Headrest 20 is in the extended position. In FIG. 8, a force has been exerted by cable 56 on clutch 38, causing clutch 38 to rotate. When clutch 38 rotates, pin 42 moves within first cam 40 to a position proximal to lock 44. This movement allows button 79 to disengage from mounting bracket 32. Rotation of clutch 38 results in movement of lever arm 54, which causes spring 46 to become more compressed.

[0045] FIG. 9 shows button 79 disengaged from mounting bracket 32. Pin 42 is shown in first cam 40 in a position proximal to lock 44. FIG. 10 shows the movement of lever arm 54. Lock 44 has moved along rotatable shaft 36. Cross-member 78 slides within slot 76.

[0046] FIGS. 11–13 shows the headrest mechanism 30 with button 79 disengaged from mounting bracket 32. Rotation bracket 34 has been pivoted. Headrest 20 is in the partially stowed position. Rotation bracket 34 has been rotated forward. By following first cam 40, pin 42 has moved into a proximal position with lock 44. Clutch 38 will no longer rotate relative to rotatable shaft 36, thus causing rotatable shaft 36 and rotation bracket 34 to turn. As shown, button 79 is no longer within button aperture 84.

[0047] Rotation bracket 34 can continue to turn, until the back portion of rotation bracket 34 comes into contact with stop 50. When the back portion of rotation bracket 34 comes into contact with stop 50, then headrest 20 would be in the stowed position. Stop 50 can be positioned on rotation bracket 34 so that rotation bracket can pivot only a predetermined number of degrees.

[0048] As clutch 38 turns in a first direction, spring 46 is compressed. Spring 46 exerts a force on lever arm 54 in a direction opposite to that of the to the rotation. Thus, when tension on cable 56 is removed, then spring 46 by way of lever arm 54 causes clutch 38 to rotate in a second direction. The second direction is opposite to that of the first direction. Pin 42 travels from its position proximal to lock 44 to a position distal from lock 44, whereupon pin 42 causes rotatable shaft 36 and rotation bracket 34 to turn. Button 79 will eventually reengage with button aperture 84, thus preventing further movement of the rotatable shaft 36.

[0049] As noted previously, clutch 38 has second cam 77. Pin 42 also extends into second cam 77. The operation of pin 42 and second cam 77 is similar to the operation of pin 42 and first cam 40. As can be seen, while the pin moves within cams 40, 77, bun 33 does not move. When pin 42 reaches the end of cams 40, 77, then bun 33 begin pivoting about the rotatable shaft 36. Thus, the length of cam 40, 77 determines the period of time before bun 33 begins to move. The angle of cam 40 and second cam 77 with the clutch axis determines the length of cam 40, 77 and thus determines the period of time which elapses prior to movement of bun 33.

[0050] FIGS. 14–16 show the mechanism in the stowed position.

[0051] The above description is of the preferred embodiment. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any references to claim elements in the singular, for example, using the articles “a,” “an,” “the,” or “said,” is not to be construed as limiting the element to the singular.