Vehicle seat with backrest part adjustment

Chairs and seats – Movable back – Tiltable

Reexamination Certificate

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Details

C297S362000

Reexamination Certificate

active

06193316

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a vehicle seat having a seat part and a backrest part swivellably arranged thereon as well as a backrest adjusting device for adjusting the inclination of the backrest part. The backrest adjusting device comprises at least one rod element which is arranged crosswise in the transition area between the backrest part and the seat part and is supported with its upper end on the backrest part and with its lower end on the seat part. The rod element is a control-arm-type lever whose upper end is coupled to the backrest part with respect to movements and whose lower end can be displaced for adjusting the inclination of the backrest part by means of a driving mechanism along a circular-arc-shaped path (KH) between end positions.
DE-OS 22 40 692 illustrates a vehicle seat having a seat part and a backrest part which is swivellably arranged thereon. A backrest adjusting device is provided which has at least one rod element in the form of a control-arm-type lever for adjusting the inclination of the backrest part. This control-arm-type lever is arranged crosswise in the transition area between the backrest part and the seat part. The upper end of the control-arm-type lever is supported on the backrest part and is coupled thereto with respect to movements. The lower end of the control-arm-type lever is supported by a driving mechanism on the seat part. For adjusting the inclination of the backrest part, the driving mechanism comprises a rocker which can be swivelled in the manner of a crank by a transmission, and to which the lower end of the control-arm-type lever is connected in an articulated manner and can be displaced along a circular arc between end positions. Together with the control-arm-type lever, the rocker forms a type of toggle lever drive.
It is a disadvantage of this known vehicle seat that the rocker, which can be swivelled by the transmission, must be arranged at a considerable distance in front of the backrest, so that the toggle lever drive has a lever effect which is suitable for adjusting the inclination of the backrest part. As a result, a relatively large amount of space is required on the vehicle seat. This requirement disadvantageously impairs the vehicle occupant's sitting comfort.
DE 17 55 333 C3 (corresponding to U.S. Pat. No. 3,583,762) shows a vehicle seat constructed as a bucket seat, and having a seat part and a backrest part which is swivellably arranged thereon. For adjusting the inclination of the backrest part, this vehicle seat comprises a backrest adjusting device with at least one rod element which is arranged crosswise in the transition area between the backrest part and the seat part. For this purpose, the rod element, which is constructed as a threaded spindle, engages by its upper and lower end respectively. The threaded nuts are arranged on the backrest part and the seat part of the vehicle seat and have threads in opposite directions. By rotating the threaded spindle by way of a hand wheel fastened thereto, the spacing of the threaded nuts arranged on the seat part and the backrest part can be changed and the inclination of the backrest part can thereby be adjusted with respect to the seat part.
In this known vehicle seat, the adjustment of the inclination of the seat part by rotating the threaded spindle is, however, not very comfortable. In addition, the threaded spindle requires a relatively large amount of space, in which case, laterally in the area between the seat part and the backrest part, the seat cheeks and backrest must be cut out to a relatively large extent in order to ensure a free accessibility to the hand wheel of the threaded spindle. In one embodiment in which threaded rods are provided on both sides of the vehicle seat, no protection device is provided with respect to a non-uniform rotation of both threaded rods so it is possible that the two rod elements may be deformed.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a vehicle seat which permits a comfortable adjustment of the backrest part and a compact space-saving arrangement of the backrest adjusting device in the transition area between the backrest part and the seat part.
According to the invention, this object has been achieved by providing a vehicle seat in which an end of a curved toothed rack is linked to the lever, and a driving pinion of the driving mechanism engages with the toothed rack, by means of which driving pinion the toothed rack can be swivelled about the center point (axis ZZ) of the circular-arc-shaped path (KH).
In the vehicle seat according to the present invention, an end of a curved toothed rack is linked to the lever, and a driving pinion of a driving mechanism is engaged with the toothed rack. A particularly space-saving and robust arrangement of the backrest adjusting device is achieved which, particularly also in the case of a vehicle seat with a narrow cushioning thickness, as, for example, in the case of a bucket seat, can be used in the transition area between the backrest part and the seat part. Because the lower end of the lever can be moved by the toothed rack along the circular-arc-shaped path, the backrest part can be adjusted in a relatively uniform manner and, as a result, can be driven particularly well by a motor, with the driving mechanism with the motor preferably being arranged below the seat part. The lateral incisions between the seat part and the backrest part can be dimensioned to be relatively small, because only the swivellability of the backrest part must be ensured. In addition, the lever is arranged in space-saving manner crosswise in the transition area between the backrest part and the seat part and is covered by a simply constructed covering.
In a further development of the invention, it has been found particularly advantageous to use two synchronously movable levers, in which because of the distributed forces, the backrest adjusting device can be dimensioned to be relatively small and simultaneously a reliable drive of the backrest part can be provided.
If, relative to the side contour of the seat part, the levers are arranged to be rebounding at least in areas, a seat of relatively narrow construction is achieved.
In addition, it has been found advantageous to link the levers to bent side cheeks of the backrest part. As a result, a spacing of moments between the respective upper end of the levers and the swivelling axis or the connection section, which is required for adjusting the inclination, can be selected particularly advantageously.
In a still further embodiment of the invention, the seat part has a passage opening for the assigned lever in lateral edge areas, so that the driving mechanism can be arranged in a space-saving manner below the seat part. If the seat part and the backrest part are connected with one another by a bending-elastic connection section, a fixed swivelling axis between the seat part and the backrest part will be unnecessary.
Finally, if the carrying structure of the seat part and backrest part as well as of the connection section is constructed in one piece, the bucket seat can be produced in a particularly simple and stable manner. In this embodiment, lateral incisions, which reduce the bending resistance, are provided in the area of the connection section, in order to ensure a smooth running adjustment of the inclination of the backrest part.


REFERENCES:
patent: 185189 (1876-12-01), Platt
patent: 242170 (1881-05-01), Van Pelt
patent: 3583762 (1971-06-01), Strien
patent: 5203532 (1993-04-01), Matsuura
patent: 5295730 (1994-03-01), Rees
patent: 5435624 (1995-07-01), Bray et al.
patent: 5702155 (1997-12-01), Ito

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