GB2117441A

GB2117441A - Seat reclining mechanism

Info

Publication number: GB2117441A
Application number: GB08306514A
Authority: GB
Inventors: Thomas Robert Joyner
Original assignee: IHW Engeneering Ltd; AJC Johnson Controls Ltd
Current assignee: AJC Johnson Controls Ltd
Priority date: 1982-03-13
Filing date: 1983-03-09
Publication date: 1983-10-12
Also published as: GB8306514D0; GB2117441B

Abstract

A seat reclining mechanism has a first member 2 attachable to a seat cushion and a second member 4 attachable to a seat back. The first and second members are pivoted together through a gear mechanism 1 which has a drive shaft 6, rotation of which causes the seat back to pivot relative to the cushion. The drive shaft 6 is driven by a ratchet drive 8 in place of the conventional hand wheel. The ratchet drive may comprise a handle 13a from which an actuating bar 17 protrudes. Depression of the bar 17 into the handle 13a engages a pawl 15b with a toothed drive wheel 14 coupled to the drive shaft 6. Turning the handle about the shaft then rotates the gear mechanism to adjust the angle between the seat back and the cushion. <IMAGE>

Description

SPECIFICATION Seat reclining mechanism This invention is concerned with a seat reclining mechanism suitable for use with a motor vehicle seat.

It is known to provide a seat reclining mechanism in which the rotation of the shaft adjusts, through a differential gearing, the angle between the seat back and the seat cushion. One such mechanism is disclosed in our Patent Specification No: 1 528357.

In seat reclining mechanisms it is customary to provide a hand wheel to rotate the shaft. Owing to the construction of motor vehicles and the distance between adjacent seats it is sometimes difficult to place the hand wheel at a position where it is readily accessible to the user of the vehicle so that he can readily rotate the hand wheel and adjust the seat to his liking.

The present invention provides an alternative to a hand wheel for a seat reclining mechanism.

Accordingly the present invention provides a seat reclining mechanism comprising a first member attachable to a seat cushion, a second member attachable to a seat back, the second member being pivotable relative to the first member, a gear mechanism interlinking the first and second members and operable to pivot the second member relative to the first member, and a drive means to drive the gear mechanism, wherein the drive means comprises a ratchet drive.

Preferably, the ratchet drive comprises a pawl biased out of a engagement wth a toothed drive wheel, and manually operable means are provided for manually moving the pawl into engagement with the drive wheel and for turning the pawl about the axis of rotation of the drive wheel to rotate the drive wheel.

In a specific embodiment of the invention, the mechanism includes a casing with an integral handle and the pawl is slidable within the said casing. The pawl is biased by a spring member out of engagement with a drive wheel, with which the pawl is adapted to co-operate in order to rotate the seat reclining mechanism. A plunger slidable within the handle engages an extended portion of the pawl so that by pressing the plunger the pawl may be brought into engagement with the drivable member and thereafter movement of the handle in one direction or the other will adjust the angle of the seat back relative to the cushion. Thus, each time the operator wishes to move the seat back in one direction he moves the handle to one extremity, engages the pawl and moves the handle with the pawl engaged to rotate the drivable member.He then disengages the pawl by releasing the plunger, moves the handle backto its first position, reengages the pawl by depressing the plunger and again rotates the drivable member. In order to move the seat reclining mechanism in the opposite direction the reverse sequence of movement is applied.

Reference is made to the accompanying drawings, in which: Figure 115 a partially cut-away perspective view of part of a seat-reclining mechanism in accordance with the invention; Figure 2 shows a vehicle seat with the mechanism as shown in Figure 1; and Figure 3 is an enlarged view of the mechanism as installed in the seat, corresponding with Figure 2.

The gear mechanism 1 is of the type described in our Patent Specification No:1 520 357, and will therefore not be described here in detail. The gear mechanism 1 includes a first member 2 which is attached to the seat back 3 and a second member 4 which is attached to the seat frame at the side of the seat cushion 5. A drive shaft 6 extends from the gear mechanism 1, and carries a toothed drive transfer member 7, rotation of which turns the shaft 6.

A ratchet drive and handle assembly 8 is mounted for rotation about the shaft 6 and comprises a pair of outer plates 9 and 10 which are secured together in spaced apart relationship by a pair of rivets 11 and 12. The outer plates 9 and 10 are encased within a cover 13 moulded in a plastics material and having a hollow handle portion 13a extending from one end thereof. A toothed drive wheel 14 is located on the shaft 6 between the outer plates 9 and 10. The drive wheel 14 has its teeth on a circumferential flange 14a so as to provide a step up to an integrally formed disc 1 4b on each face of the wheel. The discs 1 4b fit rotatably into a corresponding circular aperture in each outer plate 9 and 10.The innermost disc (not shown) has a slotted generally circular aperture therein which co-operates with the drive transfer member 7 whereby rotation of the drive wheel 14 causes the gear mechanism 1 to be driven.

A sliding plate 15 is slidably mounted between the outer plates 9 and 10 and has an aperture 15a which surrounds and is large than the drive wheel 14. A portion 15b of the edge of the aperture is shaped to define a pawl which can engage with the teeth of the drive wheel. The sliding plate 15 also contains a closed slot 1 sic to accommodate one of the rivets 11 and an open slot 15dto accommodate the second rivet 12, with a compression spring 16 between the rivet 12 and the end of the slot 15dto urge the sliding plate 15 to a position in which the pawl 1 sub is remote from the drive wheel 14.A tongue 15e extends from the sliding plate at the end thereof adjacent to the spring 16, the tongue extending into the hollow handle portion 13a, where the tongue fits into an actuating bar 17 which can slide within the handle 13a. As the actuating bar 17 is pushed into the handle, the pawl is urged into engagement with the teeth on the drive wheel 14.

The ratchet drive and handle assembly 8 may also include, if desired, a spring to bias the handle towards a rest position as illustrated in Figures 2 and 3.

To recline the seat back 3 so as to increase the angle between the back 3 and the cusion 5 (see Figure 2), the bar 17 is pressed into the handle to engage the pawl with the drive wheel and the handle is then moved anti-clockwise through whatever angle is convenient for the user, possibly of the order of 45 The bar 17 is then released and the handle returned to the start position. The procedure may then be repeated until the desired angle is achieved. To decrease the angle, the handle is lifted first before the bar 17 is pushed in to engage the pawl as the handle is moved back towards the rest position.

Claims

1. A seat reclining mechanism comprising a first member attachable to a seat cushion, a second member attachable to a seat back, the second member being pivotable relative to the first member, a gear mechanism interlinking the first and second members and operable to pivot the second member relative to the first member and a drive means to drive the gear mechanism, wherein the drive means comprises a ratchet drive.

2. A seat reclining mechanism according to Claim 1, wherein the ratchet drive comprises a pawl biased out of a engagement with a toothed drive wheel, and manually operable means are provided for manually moving the pawl into engagement with the drive wheel and for turning the pawl about the axis of rotation of the drive wheel to rotate the drive wheel.

3. A seat reclining mechanism according to Claim 2, wherein the manually operable means comprise a handle which is pivoted about the axis of the drive wheel and has a component slidable relative thereto, sliding of the component causing movement of the pawl towards or away from the drive wheel.

4. A seat reclining mechanism according to Claim 3, wherein the handle is biased about the pivot thereof towards the rest position.

5. A seat reclining mechanism according to any preceding claim, comprising a spaced pair of outer plates secured together and having a hollow handle attached thereto, the outer plates being mounted for rotation about the axis of a drive shaft connected to the gear mechanism, and containing therebetween a toothed drive wheel fixed to the shaft and a sliding plate having therein an aperture larger than, and surrounding, the drive wheel, a portion of the edge of the aperture being shaped to defined a pawl engageable with the teeth of the drive wheel, the sliding plate being engageable by an actuating member slidable within the hollow handle and extending from the free end thereof, a compression spring extending between the sliding plate and a post fixed between the two outer plates and serving to bias the pawl away from the drive wheel.

6. A seat reclining mechanism according to any preceding claim, wherein the gear mechanism comprises an internally toothed ring gear associated with each of the members, one ring gear having more teeth than the other ring gear, an adjustment gear located within the two ring gears, and control means for moving the adjustment gear in engagement with the ring gears to cause relative pivoting of the two members.

7. A seat reclining mechanism according to Claim 6, wherein the control means comprise a control gear in mesh with the adjustment gear and a drive shaft for rotating the control gear.

8. A seat reclining mechanism according to Claim 7, wherein a plurality of adjustment gears are provided.

9. A seat reclining mechanism, substantially as described with reference to, or as shown in, the drawings.