GB2235620A

GB2235620A - Reclining seat frame

Info

Publication number: GB2235620A
Application number: GB8920165A
Authority: GB
Inventors: Simon Griffiths
Original assignee: IHW Engeneering Ltd; AJC Johnson Controls Ltd
Current assignee: AJC Johnson Controls Ltd
Priority date: 1989-09-06
Filing date: 1989-09-06
Publication date: 1991-03-13
Anticipated expiration: 2009-09-06
Also published as: GB2235620B; GB8920165D0

Abstract

A reclining seat frame comprises a seat cushion frame hingedly connected to a seat back frame by a pair of angularly adjustable hinge assemblies (20) spaced apart along the hinge axis, each hinge assembly including a rotatable adjustment member which on rotation causes angular adjustment of the hinge assembly, the adjustment member of one hinge assembly being drivingly connected to the adjustment member of the other hinge assembly by a flexible drive shaft (40). The drive shaft (40) may be rotatably anchored to one of either of the cushion or back frames, and, as shown, it may be received in a sleeve (42) secured to a cranked crossmember (31) of the back frame, or it may be located within the crossmember (31). The drive shaft may be bi-directional and be formed from concentric layers of helical windings in which successive layers are wound in opposite directions. <IMAGE>

Description

RECLINING SEAT FRAME The present invention relates to reclining seat frames, in particular reclining seat frames for use in vehicle.

According to one aspect of the present invention there is provided a reclining seat frame comprising a seat cushion frame hingedly connected to a seat squab frame by a pair of angularly adjustable hinge assemblies spaced apart along the hinge axis, each hinge assembly including a rotatable adjustment member which on rotation causes angular adjustment of the hinge assembly, the adjustment member of one hinge assembly being drivingly connected to the adjustment member of the other hinge assembly by a flexible drive shaft.

Preferably the flexible drive shaft is rotatably anchored to one of either the squab or back frames so that its central portion is spaced from the hinge axis.

Conveniently the flexible drive shaft comprises a plurality of helical windings which are arranged to enable torque to be transmitted in both rotational directions.

Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of a reclining seat frame according to one embodiment of the invention Figure 2 is a part front view of the frame shown in Figure 1 The reclining seat frame 10 illustrated in the drawings includes a seat cushion frame 12 which is hingedly connected to a seat squab frame 14 by a pair of hinge assemblies 20.

Each frame 12,14 is formed from a tubular frame element 30 which is bent to assume a general U shape having spaced arms 33 and a rigid cross-member 31 which is secured adjacent the terminal ends of arms 33.

A cushion support 35 is suspended from arms 33 by a series of springs 36 and forms the support for a cushion material of the seat, such as, for example, a plastics foam.

Each hinge assembly includes a pair of arms 21,22 which are angularly displaceable relative to one another; arm 21 being secured to the arms 33 of the seat back frame 14 and arm 22 being secured to the arms 33 of the seat squab frame 12. An example of a suitable hinge assembly is disclosed in our UK patent 1528357.

Each hinge assembly 20 includes a rotatable adjustment member 24 (Figure 2) which on rotation causes angular adjustment of the associated arms 21,22 and thereby causes angular displacement between each frame 12,14. One hinge assembly is provided with a handle 28 secured to an extension of its adjustment member 24 so that rotation of the handle 28 causes adjustment of both hinge assemblies.

The adjustment members 24 of the pair of hinge assemblies 20 are drivingly connected by a flexible drive shaft 40.

The drive shaft 40 is rotatably located in a sleeve 42 which is secured to the cross-member 31 of frame 14.

The sleeve 42 can be, for example, 30 to 80mm in length.

Cross-member 31 of frame 14 is cranked so as to extend rearwardly of arms 33 to which it is connected and so position the central portion of the flexible drive shaft at a rearwardly spaced relationship to the hinge axis between frames 12 and 14.

In an alternative embodiment, the drive shaft 40 can be located within the cross-member 31; the crossmember having the configuration of the drive shaft 40 as shown in Figure 1.

The amount by which the central portion of the drive shaft is spaced rearwardly of the hinge axis is chosen so as to be sufficient to avoid a person feeling the drive shaft when seated in the finished seat. This may vary dependant upon the amount of covering applied to the seat but it is envisaged that in cases of a minimum amount of covering, the drive shaft will be positioned rearwardly by about 50 to 60mm from the hinge axis.

The drive shaft 40 is bi-directional, ie it is able to transmit torque in both rotational directions. The drive shaft 40 is preferably formed from concentric layers of helical windings in which successive layers are wound in opposite directions. With such a construction the amount of torque capable of being transmitted in one rotational direction tends to be greater than that transmitted in the opposite rotational direction. This type of flexible drive shaft is well known and is commonly used for electric power adjustment of seats but generally at sifnificantly lower torque and higher speeds. In the present invention, the flexible drive shaft is arranged such that its rotational direction capable of transmitting the larger torque causes the seat back frame to hinge rearwardly. This is acceptable since the weight of the trimmed seat squab in the chair reduces the torque requirement when the seat back is tipped rearwardly.

As indicated above the central portion of the flexible drive is spaced from the hinge axis and this enables thinner cushion covering materials to be used without the flexible shaft being felt by a person seated in the seat. It is envisaged that the central portion of the drive shaft may be rotationally anchored in a different manner to that described above, for instance, it may be anchored to the cross-member 31 of the squab frame 12.

Claims

1. A reclining seat frame comprising a seat cushion frame hingedly connected to a seat squab frame by a pair of angularly adjustable hinge assemblies spaced apart along the hinge axis, each hinge assembly including a rotatable adjustment member which on rotation causes angular adjustment of the hinge assembly, the adjustment member of one hinge assembly being drivingly connected to the adjustment member of the other hinge assembly by a flexible drive shaft.

2. A reclining seat frame according to Claim 1, wherein the flexible drive shaft is rotatably anchored to one of either the squab or back frames so that its central portion is spaced from the hinge axis.

3. A reclining seat frame according to Claim 2, wherein the flexible drive shaft is rotatably received in a sleeve secured to a cross-member of the back frame.

4. A reclining seat frame according to Claim 2, wherein the back frame includes a cranked cross-member extending between the pair of angularly adjustable hinge assemblies and the flexible drive shaft is located within said cross-member.

5. A reclining seat frame according to any of Claims 2 to 4, wherein the central portion of the drive shaft is positioned about 50 - 60mm. from the hinge axis.

6. A reclining seat frame according to any preceding Claim, wherein the flexible drive shaft is bi-directional so as to be able to transmit torque in both directions.

7. A reclining seat frame according to Claim 6, wherein the drive shaft is formed from concentric layers of helical windings in which successive layers are wound in opposite directions.

8. A reclining seat frame substantially as described herein with reference to and as illustrated in the accompanying drawings.