GB2154275A

GB2154275A - Seat reclining mechanism

Info

Publication number: GB2154275A
Application number: GB08501823A
Authority: GB
Inventors: Neil Harrison
Original assignee: IHW Engeneering Ltd; AJC Johnson Controls Ltd
Current assignee: AJC Johnson Controls Ltd
Priority date: 1984-01-25
Filing date: 1985-01-24
Publication date: 1985-09-04
Also published as: GB8501823D0; GB8401872D0; GB2154275B

Abstract

The mechanism provides both fine and coarse adjustment to the position of the seat back relative to the seat cushion. It comprises a control mechanism (4) which provides continuous variation of the angle between the seat back (3) and a second member (5) which is linked to the seat cushion by a latch (8) which engages an externally toothed portion (7) on the second member the latch is movable by means of a hand lever (10) pivotally mounted on the side of the seat cushion and spring biassed. Coarse adjustment is effected by the latch and final adjustment by the mechanism (4). <IMAGE>

Description

SPECIFICATION Seat reclining mechanism This invention relates to a device for selectively varying the angle between the back and the cushion of a seat, commonly referred to as a "seat reclining mechanism", and to a seat including such a device.

It is becoming increasingly common to use infinitely variable self-locking reclining mechanisms on vehicle seats. In order to minimise the force required to rotate the handwheels driving such mechanisms, the gearing is typically arranged to provide a relatively high drive ratio between the handwheel and the seat member which is driven. This results in a large number of turns of the handwheel being necessary to move the seat back between a fully reclined and a fully upright position.

An object of the invention is to provide a device which will permit both fine and coarse adjustment of the position of the seat back relative to the seat cushion.

According to the invention a device for selectively varying the angle between the back and the cushion of a seat comprises a control mechanism operable to provide continuous variation of said angle and arranged to prevent movement of the seat back relative to the seat cushion when the mechanism is not operated, and means for selectively disengaging the control mechanism.

A preferred embodiment of the device has relatively pivotable first and second members linked by the control mechanism and pivotally coupled to the seat cushion, the first member being an arm connectible to the seat back, and detent means selectively coupling the second member and the seat cushion whereby the second member may be held in any of a plurality of different angular positions relative to the seat cushion. Preferably the second member comprises an externally toothed quadrant gear, and a latch spring-biased into locking engagement therewith is mounted on the seat cushion frame. The latch is preferably linked to a manually operable lever on the side of the seat cushion, adjacent to a handwheel for driving the control mechanism.

The invention also provides a vehicle seat having a back frame and a cushion frame coupled together on each side of the seat by a device in accordance with the invention, wherein each side of the seat is provided with a return spring biassing the back frame forwardly towards the cushion frame.

Preferably, one of the devices is provided with a hand lever to operate the latch, and the latch on the other device is operatively linked to the hand lever.

The latches may be linked by a rigid rod across the seat, or by a control cable.

If described, a spring may be used to cause the seat back to pivot forwards when the latch is released, assisting in adjustment and preventing collapse of the seat back rearwardly when released. The spring will urge the seat back into contact with the occupant of the seat, who can then lean backwards to the desired inclination against the spring, before locking the seat back with the latch. Preferably, a pair of springs is used, one on each side of the seat. This arrangement premits a lighter frame construction to be adopted without risk of distortion, resulting in misalignment of the latch or latches.

The device may be arranged to permit the seat back to be pivoted freely forward to permit access to the rear seats of a motor vehicle via the front door. The device of the invention permits the seat back to be moved rapidly to an inclination near to the desired inclination, final adjustment being by means of the control mechanism in conventional manner.

Reference is made to the drawings, in which: Figure 1 is a partial side elevation of a device in accordance with the invention; and Figure 2 is a section on line A-A in Fig. 1.

The mechanism has a pair of arms which pivot about a shaft 1. The first arm 2 is in the form of a bracket securable to the side of the seat cushion frame, and the second arm 3 is in the form of a bracket attachable to the side of the seat back frame. The gear mechanism 4 of the device is of the type described and claimed in our earlier Patent Specification No.

1,528,357 and comprises a pair of internally toothed gear rings with four planetary gears in engagement therewith and in engagement with a central drive gear. One of the gear rings is provided by a shaped recess in the arm 3, and the other gear ring is formed by a shaped recess in a second member 5 which also pivots about the shaft 1. Rotation of the shaft 1 by means of a handwheel 6 drives the gear mechanism and causes the arm 3 to be rotated about the shaft 1 relative to the second member 5.

The second member 5 is provided with an externally toothed portion 7 engageable by a latching member 8 mounted on the first arm 2. The latch 8 comprises a steel bar pivotally attached to a lever 9 on one side of the first arm 2 and passing through a slot 9 therein to be bent back into engagement with the opposite side of the arm 2 so as to hold the latch in engagement with the first arm 2. The lever 10 is pivotally mounted on the side of the first arm 2 and is provided with a spring 11 which biasses the lever upwardly, thus biassing the latch into engagement with the gear toothed portion 7 on the second member 5.

The latch 8 is guided by the guide formations 1 2 pressed into the side of the first arm 2.

In use, coarse adjustment of the position of the seat back relative to the seat cushion is achieved by pressing downwards on the lever 10 to release the latch from the gear formation 7. The back is then rotated to the desired position and the lever is released to reengage the latch, locking the seat back at an inclination nearest to the desired position. Final adjustment is then achieved by rotating the handwheel 6 to drive the gear mechanism, for example in the manner described in our ear lier Patent Specifiction No. 1,528,357.

Claims

1. A device for selectively varying the angle between the back and the cushion of a seat comprising a control mechanism operable to provide continuous variation of said angle and arranged to prevent movement of the seat back relative to the seat cushion when the mechanism is not operated, and means to selectively disengaging the control mechanism.

2. A device according to Claim 1, comprising relatively pivotable first and second members linked by the control mechanism, the first member being an arm connectable to the seat back, and the second member being selectively coupled to the seat cushion by detent means whereby the second member may be held in any of a plurality of different angular positions relative to the seat cushion, wherein the second member has a plurality of indents selectively engageable by the detent means

3. A device according to Claim 2, wherein the second member comprising an externally toothed quadrant gear.

4. A device according to Claim 2 or 3, wherein the detent means comprise a spring biassed latch.

5. A device according to Claim 4, wherein the latch is actuated by a hand lever pivotally mounted on the seat cushion frame.

6. A vehicle seat having a back frame and a cushion frame coupled together on each side of the seat by a device according to Claim 3 or 4, wherein each side of the seat is provided with a return spring biassing the back frame forwardly towards the cushion frame.

7. A vehicle seat according to Claim 6, wherein one of the device is provided with a hand lever to operate the latch, and the latch on the other device is operatively linked to the hand lever.

8. A vehicle seat according to Claim 7, wherein the latch on the other device is operatively linked the hand lever by a rigid connecting rod across the seat.

9. A vehicle seat according to Claim 7, wherein the other device is operatively linked to the hand lever by a control cable.

1 0. A device for selectively varying the angle between the back and the cushion of a seat, substantially as described with reference to, or as shown in, the drawings.

11. A vehicle seat having a back frame and a cushion frame coupled together on at least one side thereof by a device according to Claim 10.