GB2288729A

GB2288729A - Adjustment of a vehicle seat backrest

Info

Publication number: GB2288729A
Application number: GB9502461A
Authority: GB
Inventors: Dieter Falk
Original assignee: Rentrop Hubbert & Wagner
Current assignee: Rentrop Hubbert & Wagner
Priority date: 1994-04-30
Filing date: 1995-02-08
Publication date: 1995-11-01
Also published as: GB9502461D0

Abstract

A rotary adjustment device for the backrest 10 of a motor vehicle seat unit 9 has a worm wheel 2 which is mounted coaxial with the horizontal swivel axis 3 of the backrest. The wheel 2 is driven by a worm 1 which, in turn, is driven by a hand wheel 5 via level gears (6, 7, Fig. 2). The drive is self-locking. <IMAGE>

Description

Rotary adjustment device for a vehicle seat backrest The present invention relates to a rotary adjustment device according to the preamble of claim 1.

Rotary adjustment devices of this kind are known in various different designs. The most widespread are rotary adjustment devices which are designed as tumbler gears or hypocycloid gears. None of the gears of this kind is selflocking but in order to meet the demands placed on them these gears require braking devices which make the fitments complicated and expensive.

The object of the invention is to provide a rotary adjustment device which is designed as a self-locking gear.

This is achieved with the features of the characteristic part of claim 1.

Preferred embodiments of the invention are described in the sub-claims.

The advantage of designing the adjustment gear on the rotary adjustment device as a worm gear is that the gear becomes self-locking. It is uncomplicated in construction and can be easily installed between the backrest and seat unit.

In a preferred embodiment the drive of the worm is provided by a first bevel wheel fixed coaxially with the worm and meshing with a second bevel wheel which is in turn rotationally secured to the hand drive wheel.

The principle of the drive based on worm and worm wheel can be implemented in different ways. In a first embodiment the worm wheel is secured to the seat unit whilst the worm is rotatably journalled in or on the backrest. With this embodiment the worm moves over the circumference of the worm wheel. It thereby shifts the rotary axis of the hand wheel.

In a second embodiment the worm wheel which is mounted coaxial with the swivel axis of the backrest is secured to the backrest whilst the worm is in turn rotatably journalled in or on the seat unit. With this embodiment the position of the rotary axis of the hand wheel does not change.

A preferred embodiment of the invention will now be explained in detail with reference to the drawing in which: Figure 1 is a diagrammatic side view of the rotary adjustment device; Figure 2 is a plan view in the direction of arrow II according to Figure 1 wherein the backrest side beam 10 and the side beam 9 of the seat unit, visible in Figure 1 are omitted; Figure 3 is a view in the direction of arrow III according to Figure 1.

Of the backrest 10 only the backrest side beam is shown in the drawings. The seat unit 9 is characterised by the corresponding side beam.

In the illustrated embodiment the backrest 10 is mounted to swivel about a horizontal axis 3. The horizontal axis 3 is formed by the tube 11. A worm wheel 2 is mounted on the seat unit 9 coaxial with the swivel axis 3, and connected to the seat by a rivet 12. A worm 1 rotatable about a horizontal axis 8 running in the longitudinal direction of the vehicle and rotatably mounted in bearing blocks 13 on the backrest 10 meshes with the worm wheel 2. The worm 1 carries at one end a first bevel wheel 7 which is secured to the worm 1. The first bevel wheel 7 meshes with a second bevel wheel 6 which is mounted on the side beam of the backrest 10, and rotatable about a horizontal axis 4. The second bevel wheel 6 is secured to and rotatable by a hand drive wheel 5. The rotary axis 4 runs parallel to the swivel axis 3. With the illustrated embodiment the axis 4 moves during adjustment on a circular arc round the swivel axis 3.

With a kinematic reversal the arrangement is unchanged from Figures 1 and 2. With this kinematic reversal the rotary axis 4 is locally fixed just like the swivel axis 3. With this embodiment, as the handwheel 5 is turned so the worm 1 is drive by the second bevel wheel 6 and first bevel wheel 7 and in turn turns the worm wheel 2 about the swivel axis 3. Since the worm wheel 2 in this second embodiment is secured to the backrest 10, the backrest 10 is swivelled as the handwheel 5 is rotated.

Claims

PATENT CLAINS

1. A rotary adjustment device for the backrest of a motor vehicle seat wherein the backrest is attached to the seat unit to swivel about a horizontal axis, with a drive wheel and a gearing designed to engage with the drive wheel, characterised in that the drive wheel comprises a worm which meshes with a worm wheel which is mounted coaxial with the horizontal swivel axis.

2. A rotary adjustment device according to claim 1, characterised in that the worm has a first bevel wheel fixed coaxially thereon and meshing with a second bevel wheel which is mounted coaxial with a hand drive wheel and is rotationally secured thereto wherein the axis of rotation of the hand drive wheel and second bevel wheel runs parallel to the swivel axis of the backrest.

3. A rotary adjustment device according to claim 1 or 2 characterised in that the worm wheel is secured to the seat unit and the worm is rotatably journalled in or on the backrest.

4. A rotary adjustment device according to claim 1 or 2 characterised in that the worm wheel is secured to the backrest and the worm is rotatably journalled in or on the seat unit.

5. A rotary adjustment device for the backrest of a motor vehicle seat substantially as herein described with reference to any one of the drawings.