Seat for Automobile

The present invention relates to a seat for an automobile and, more particularly, to a seat for an automobile having a hip support for supporting the hip region of an occupant of the vehicle.

Seats of this type are disclosed in Japanese Utility Model Laid-Open Nos. 174462/1986 and 101850/1984.

The former Japanese Utility Model Laid-Open No. 174462/1986 discloses an arrangement in which a space is defined within a lower portion of a seat back, a hip support being accommodated within the space in such a manner as to be movable in the forward direction about its lower portion serving as a fulcrum, and when an occupant assumes a seated position in which his hip is moved forwardly, the hip support is moved forwardly so as to project outwardly from a front surface of the seat back, thereby allowing the occupant's hip to be supported by means of this projecting portion. With this arrangement however, when the occupant feels that the support of his hip is insufficient, it is necessary for him to rise up and seat himself again after moving the hip support forwardly a predetermined distance.

In the latter Japanese Utility Model Laid-Open No. 101830/1984, an arrangement is disclosed in accordance with which a space is defined within a lower portion of a seat back, a hip support being disposed within the space in such a manner as to be pivotable back and forth with an upper portion thereof serving as a fulcrum, and a seat plate is connected to a lower portion of the hip support by means of a hinge in such a manner as to be movable back and forth upon a seat cushion. With this arrangement, the occupant is seated upon the seat cushion by means of the seat plate. Accordingly, when the occupant feels that the support of his hip is insufficient, it is necessary for the occupant to rise up, move the hip support forward by pulling the seat plate in the forward direction, and then be seated again.

Thus, with the above-described two examples of the prior art, a drawback is encountered in that the occupant cannot adjust the position of the hip support while being seated.

If a lower region of the lumbar vertebrae is supported by means of a hip support, there is an advantage in that general lumbagos can be alleviated. In addition, if the sacral vertebrae are supported, there is an advantage in that the occupant is able to maintain a stable posture by receiving a reactionary force which occurs when he depresses a pedal of the automobile.

However, with the above-described two examples of the prior art, since a predetermined region of the occupant at a fixed height along the spinal column is to be encountered in order to obtain support, there is the problem that unless the occupant assumes an unnatural posture by moving vertically with respect to the seat, he cannot arbitrarily select the region to be acted upon between the lower region of the lumbar vertebrae and the sacral vertebrae.

Accordingly, an object of the present invention is to provide a seat which allows an occupant of a vehicle to adjust the position of a hip support while being seated, thereby overcoming the above-described drawbacks of the prior art.

Another object of the present invention is to provide a seat for an automobile which allows an occupant of a vehicle to select either the sacral vertebrae or a lower region of the lumbar vertebrae as the region to be supported.

To these ends, in accordance with the present invention, there is provided a seat comprising: a seat cushion; a seat back connected to the seat cushion, a space being defined within a lower portion thereof; a rod pivotably interposed between opposite side frames of the seat back; a hip support secured upon an intermediate portion of the rod and disposed within the space defined within the seat back; a pressure or support board disposed upon a support frame provided within the hip support, in such a manner as to be pivoted back and forth, whereby an upper portion of the pressure or support board serves as a member for pressing or supporting a lower region of the lumbar vertebrae during forward inclination or pivotal movement thereof, while a lower portion thereof serves as a member for pressing or supporting the sacral vertebrae during a rearward inclination or pivotal movement thereof; a first operation handle for pivoting the pressure or support board by means of a brake mechanism; and a second operation handle for pivoting the rod by means of another brake mechanism.

Various other objects, features and advantages of the present invention will become more apparent from the following detailed description of the invention when read in conjunction with the accompanying drawings, in which like reference characters designate like or corresponding parts throughout the several views, and wherein:

FIG. 1 is a perspective view of an overall arrangement of a seat constructed in accordance with an embodiment of the present invention;

FIG. 2 is a partially cut-away front elevational view illustrating an essential portion of the hip support system of the embodiment shown in FIG. 1;

FIG. 3 is a cross-sectional view taken along the line 3--3 of FIG. 2;

FIG. 4 is an exploded perspective view illustrating an essential portion of the mechanism or system shown in FIG. 2;

FIG. 5 is an exploded perspective view illustrating a brake mechanism shown in FIG. 2;

FIGS. 6 and 7 are diagrams illustrating the operation of the brake mechanism shown in FIG. 5;

FIG. 8 is a rear view of a pressure or support board and its peripheral portions shown in FIG. 2;

FIG. 9 is an exploded perspective view illustrating the installation of the pressure or support board shown in FIG. 2;

FIG. 10 is a diagram taken in the direction of the arrow B in FIG. 9; and

FIG. 11 is a diagram illustrating a region of the human spine to be supported.

Referring now to FIG. 1, a description will be given of an overall arrangement of a seat constructed in accordance with an embodiment of the present invention. A space 2a is formed within a lower portion of a seat back 2 which is connected to a seat cushion 1, and a hip support 3 is disposed within this space 2a. A first operation handle or rotary control knob 4a is provided so as to adjust the vertical position of a support or pressure board (which will be described later) disposed internally within hip support 3. A second operation handle or rotary control knob 4b is similarly provided so as to adjust the back-and-forth position of the hip support 3.

Referring now to FIGS. 2-4, a description will be given of a mechanism for adjusting the position of the hip support 3 in its back and forth movement mode. Side frames 5, 6 are respectively disposed upon opposite side portions of the seat back 2. A brake mechanism 12 is attached to one side frame 5 by means of a baseplate 7.

A description will now be given of the brake mechanism 12 with reference to FIGS. 5-7. A torsion spring 17 is disposed within a brake housing 16 which is secured to the baseplate 7, in such a manner as to be brought into pressure contact with the inside wall of the brake housing 16. A core 18 provided with a notch 18a is pivotably disposed within the torsion spring 17. In addition, an outer handle shaft 19 upon which the second operation handle 4b is mounted is integrally secured to core 18. Furthermore, a pawl portion 21a of a stopper plate 21 formed integrally with a pinion 20 is disposed within the space comprising notch 18a of the core 18 so as to be interposed between hook portions 17a, 17b of the torsion spring 17. Moreover, a through-hole 18a and a through-hole 20a are respectively provided axially within core 18 and the pinion 20. An inner handle shaft 30 which will be described later is loosely inserted within these through-holes 18a, 20a in such a manner as to be axially movable with respect thereto. Hence, the pinion 20 is rotatable about the axis of the inner handle shaft 30.

Accordingly, when a rotational force is applied from the pinion 20 side of the brake mechanism, the pawl portion 21a is brought into contact with one of the hook portions 17a or 17b of the torsion spring 17 and impresses the same, as shown in FIG. 6, acting in such a manner as to radially expand the outside diameter of the torsion spring 17. For this reason, the pressure-contacting force acting between the torsion spring 17 and the brake housing 16 increases, with the result that the hook portions 17a, 17b do not move, thereby preventing the rotation of the pinion 20. Meanwhile, when an operating force is applied from the second operation handle 4b (outer handle shaft 19) side of the brake mechanism, since the hook portion 17a or 17b of the torsion spring 17 is subjected, respectively, by means of a side end portion 18b or 18c of the core 18, to a force acting in the direction of contracting the outside diameter of the torsion spring 17, as shown in FIG. 7, the pressure-contacting force acting between the torsion spring 17 and the brake housing 16 decreases. This allows the rotation of the outer handle shaft 19 to be achieved, and the torsion spring 17 is moved by as a result of being pushed by means of one of the core side end portions 18b or 18c, with the result that the pawl portion 21a rotates as a result of being contacted by means of the hook portion 17a or 17b of the torsion spring 17. Hence, the pinion 20 also rotates.

Referring back to FIGS. 2-4, a bore 7a is provided within a lower portion of the baseplate 7. A shaft 22 is pivotably disposed within this bore 7a. A driven sector gear 23 is secured to the shaft 22, and a gear portion 23a thereof meshes with the pinion 20. A non-gear portion 23b is formed at one end portion of the gear portion 23a of driven gear 23 and serves as a stopper for the pivotal movement of the driven gear 23.

A link plate 24 is loosely disposed upon the shaft 22, a stopper arm 24a capable of abutting against a side surface of the baseplate 7 being formed at one pivotable end portion of plate 24. A rod 25 is pivotably interposed between the side frames 5, 6. In other words, one end of the rod 25 is loosely disposed upon the shaft 22, while the other end thereof is loosely disposed within a bore 6a provided within the side frame 6. The end of the rod 25 upon the side frame 5 side is secured to the link plate 24 by means of a rod spacer 26. In addition, an intermediate portion of the rod 25 is disposed within the space 2a defined within the seat back 2, a support frame 27, constituting a core portion of the hip support 3, being secured to this intermediate portion of rod 25.

A weld nut 28 is secured to the other pivotal end portion of the link plate 24. This pivotal end portion of the link plate 24 and the pivotal end portion of the driven gear 23 are connected to each other by means of a bolt 29 which is threadingly engaged with the weld nut 28 in such a manner as to clamp the driven gear 23 therebetween.

Referring now to FIG. 2 and FIGS. 8-10, a description will be given of the pressure or support board and a mechanism associated therewith. The inner handle shaft 30 is loosely disposed within the outer handle shaft 19 in such a manner as to be rotatable with respect thereto. A first sprocket 31 is attached to a distal end portion of this inner handle shaft 30 by means of a screw 32. In addition, a gear shaft 33 is loosely disposed upon an end portion of the rod 25 upon the side frame 5 side in such a manner as to be rotatable with respect thereto. A second sprocket 34 is attached to this gear shaft 33 by means of a screw 35. In addition, a chain 36 is trained between the first and second sprockets 31, 34, so that the rotation of the first sprocket 31 is transmitted to the gear shaft 33.

A brake mechanism 38 is attached to a side portion of the support frame 27 by means of a bracket 37. Since the internal configuration of this brake mechanism 38 is identical with that of the above-described brake mechanism 12, a description thereof will be omitted. Serrations or splines are provided upon a distal end portion of an input shaft 39 of the brake mechanism, and a pivotal proximal end portion of a sector gear 40 meshes with this serrated portion of shaft 39. This sector gear 40 meshes with the gear shaft 33.

A distal end portion of an output shaft 41 of the brake mechanism 38 is substantially formed so as to have the configuration of a square pole. The pressure or support board comprising pressure on contact surfaces at an upper portion 42b and a lower portion 42c, and its sectional configuration is substantially triangular. One side portion of this pressure or support board 42 is pivotably secured to the support frame 27 by means of bolt 45. In addition, a square groove 42a is formed upon the rear surface of the board 42 such that, the output shaft 41 of the brake mechanism 38 is able to be disposed within this square groove 42a and be retained therein by means of a bracket plate 43 which is attached to board 42 by means of screws 44. With respect to board 42, the upper portion 42b functions as a member for contacting a lower region of the lumbar vertebrae during forward inclination or pivotal movement thereof, and the lower portion 42c functions as a member for contacting the sacral vertebrae during rearward inclination or pivotal movement thereof.

The first operation handle 4a is attached to a distal end portion of the inner handle shaft 30 by means of a screw 52 in such a manner as to project axially outwardly from the second operation handle 4b. In addition, a spring 53 is interposed between the first operation handle 4a and the second operation handle 4b, and is adapted to urge the first operation handle 4a and the inner handle shaft 30, away from the side frame 5 until the sprocket 31 is brought into contact with the baseplate 7.

The operation of the above-described arrangement will now be described hereinunder. A description will first be given of a case wherein the hip support 3 is moved back and forth by using the second operation handle 4b. FIGS. 2 and 3 illustrate a state in which the pinion 20 abuts the nongear portion 23b of the driven gear 23, and the hip support 3 is accommodated within the innermost portion of the space 2a of the seat back 2. In this state, if the second operation handle 4b is rotated so as to cause the pinion 20 to rotate clockwise, as viewed in FIG. 3, by means of the brake mechanism 12, the driven gear 23 meshing with the pinion 20 is moved in the counterclockwise direction, as viewed in FIG. 3. In conjunction with the movement of the driven gear 23, the link plate 24 with its pivotal end portion connected to the driven gear 23 also pivots in the counterclockwise direction, as viewed in FIG. 3, about the shaft 22. As the link plate 24 pivots, the rod 25 secured to the link plate 24 also pivots in the counterclockwise direction, as viewed in FIG. 3, which, in turn, causes the support frame 27 to pivotably move in the direction of projecting outwardly from the seat back 2, thereby causing the hip support 3 to project forwardly from the space 2a of the seat back 2. This movement is allowed until the stopper arm 24a of the link plate 24 is brought into contact with the side surface of the baseplate 7, or in other words, until the driven gear 23 moves to the position indicated by means of the two-dotted chain line in FIG. 3. It goes without saying that if the second operation handle 4b is rotated in the reverse direction, the hip support 3 returns to the space 2a within the seat back 2. The back-and-forth position thus adjusted is maintained by virtue of the action of the above-described brake mechanism 12 unless the second operation handle 4b is operated.

A description will now be given hereinunder of the case wherein the support board 42 is inclined by using the first operation handle 4a. If the first operation handle 4a is rotated, the first sprocket 31 rotates by means of the inner handle shaft 30. This rotation causes the sector gear 40 to rotate by means of the chain 36, the second sprocket 34, and the gear shaft 33. As the sector gear 40 rotates, the support board 42 is inclined relative to the support frame 27. If the support board 42 is inclined forwardly, its upper portion 42b projects forwardly, so that a lower region of the lumbar vertebrae located at a higher position along the spinal column can be pressed or supported. On the other hand, if the board 42 is inclined rearwardly, its lower portion 42c projects forwardly whereby the sacral vertebrae located at a lower position along the spinal column can be pressed or supported. The position of the board 42 thus adjusted can be maintained by virtue of the action of the above-described brake mechanism 38 unless the first operation handle 4a is operated.

In accordance with the above-described arrangement, by rotating the first operation handle 4a so as to cause the pressure or support board 42 to be inclined relative to the support frame 27, the occupant is capable of having a lower region of the lumbar vertebrae or the sacral vertebrae to be selectively supported. Accordingly, as shown in FIG. 11, it is possible to alleviate lumbagos in general by supporting a lower portion B of the lumbar vertebrae with the hip support or to stabilize the occupant's posture when depressing a pedal P by supporting the sacral vertebrae C.

In addition, even while the occupant is seated, it is possible for him to adjust the back-and-forth position of the hip support 3 by operating the second operation handle 4b. In addition, since that adjustment is stepless, it is possible to obtain support for the hip region with a desired strength or support.

Furthermore, in the case of the above-described embodiment, since the first and second operation handles 4a, 4b are provided upon the same axis, the operating efficiency is good. In addition, when the second operation handle 4b is operated, since the palm of the hand is used to press the first operation handle 4a, the first operation handle 4a moves in the direction toward the side frame 5, with the result that the second operation handle 4b can be securely grasped. Moreover, in terms of their external appearance, the two operation handles appear to be one handle, so that an attractive appearance can be obtained.

It should be noted that the present invention is not confined to the above-described embodiments, and various modifications are possible without departing from the spirit of the invention which is defined solely by the accompanying claims. For instance, the cross-sectional configuration of the board 42 may be a circular arc. In addition, a belt and a pulley may be used instead of the chain 36 and the sprockets 31, 34.