GB2228765A

GB2228765A - Seat reclining mechanism

Info

Publication number: GB2228765A
Application number: GB8904044A
Authority: GB
Inventors: Ian Holloway
Original assignee: IHW Engeneering Ltd; AJC Johnson Controls Ltd
Current assignee: AJC Johnson Controls Ltd
Priority date: 1989-02-22
Filing date: 1989-02-22
Publication date: 1990-09-05
Anticipated expiration: 2009-02-22
Also published as: GB2228765B; GB8904044D0

Abstract

A seat reclining mechanism includes a cushion arm (12) pivotally connected to a squab arm (11) by a gear arrangement including a drive shaft (20) drivingly connected to gears for causing relative angular displacement between said arms in response to rotation of the drive shaft, and an arresting means (25, 26) connected between the drive shaft and one of said arms for resisting rotation of the drive shaft caused by vibration. The arresting means suitably comprises a radial arm (25) secured to the shaft and carrying dimples (26) resiliently engaging a toothed ring (18) on the arm. <IMAGE>

Description

SEAT RECLINING MECHANISM The present invention relates to a seat reclining mechanism, and in particular relates to a seat reclining mechanism of the type having a cushion arm pivotally connected to a squab arm and a gear arrangement drivingly connected therebetween for causing relative angular displacement between the cushion and squab arms.

According to one aspect of the present invention there is provided a seat reclining mechanism including a cushion arm pivotally connected to a squab arm by a gear arrangement, the gear arrangement including a drive shaft drivingly connected to gears for causing relative angular displacement between said arms in response to rotation of the drive shaft, and an arresting means connected between the drive shaft and one of said arms for resisting rotation of the drive shaft caused by vibration.

Preferably the arresting means includes an arm connected to the drive shaft for rotation therewith, the arm having a resiliently biased detent which engages with an annulus formed on one of said cushion or squab arms, the annulus including toothed formations for co-operation with said detent, the annulus and shaft being co-axial so that rotation of the shaft causes the detent to engage with successive tooth formations around the annulus. Preferably the cushion or squab arm having the annulus is formed from metal sheet and includes an integral ring gear which forms part of the gear arrangement, the ring gear being formed by an offset wall portion having a toothed circumference which forms a depression on the inside face of the arm, the offset wall portion also defining the annulus on the outside face of the arm.

Various aspects of the present invention are hereinafter described with reference to the accompanying drawing in which Figure 1 is a side view of a seat reclining mechanism according to the present invention.

Figure 2 is an end view of the seat recling mechanism illustrated in Figure 1.

The seat reclining mechanism 10 is similar to the seat reclining mechanism illustrated and described in our UK patents 1528357 and 1586869 and reference should be made thereto for a fuller understanding of the mechanism.

The seat reclining mechanism 10 includes a squab arm 11 which is pivotally connected to a cushion arm 12. A gear arrangement (not shown) is provided for drivingly connecting the squab and cushion arms. A drive shaft 20 is provided for driving the gear arrangement to alter the relative angular positions therebetween.

Both the squab arm and cushion arm are metal pressings and each include a ring gear (not shown) which is preferably defined by a depression formed on the inside face of the arm. The depression is preferably created by a pressing operation and the circumference is provided with gear teeth.

The pressing operation creates an offset wall portion which on the outside face of the arm defines a raised annulus 16 having tooth formations 18 extending about its periphery.

In the drawings the raised annulus 16 formed on the cushion arm 12 is illustrated as forming part of arresting means 14 which serve to arrest movement of the drive shaft 20 in response to continuousn vibration and or torque applied in the gear arrangement by relative movement between the cushion and squab arms. The arresting means includes a resilient arm 25 which is secured to the drive shaft 20 and extends outwardly therefrom to engage the outer periphery of the annulus 14. The terminal ends of the arm 25 are each provided with a dimple which define a detent. These setents engage with the tooth formations 18 formed on the annulus.

The arm 25 is shown as extending diametrically in opposite directions from the drive shaft. It will be appreciated that the arm may only extend in one radial direction from the drive shaft or alternatively there could be provided more than one arm.

The arm 25 illustrated is preferably a pressing formed from a spring steel and the dimples 18 are formed during the pressing process. It is envisaged that the terminal ends of the arm 25 could each carry a plastics moulding on which the detent is formed. This would provide greater flexibility in designing the shape of the detent and would also provide a sound deadening characteristic.

The arresting means primarily operate to prevent the squab arm pivoting in response to vibrations caused during travel of the vehicle. Under normal conditions the vibrations are insufficient to cause relative rotation between the squab and cushion arm. However in situations where excessive vibrations are encountered, such as driving a vehicle over rough roads, it is possible for the squab arm to pivot relative to the cushion arm due to the vibrations causing the drive shaft to rotate and thereby permit loads applied to the squab arm to effect a relative angular movement between the squab and cushion arms.

The arresting means serve to prevent such movement of the drive shaft due to the detents engaging with the tooth formations on the annulus. In use, adjustment of the reclining mechanism is achieved by rotating the drive shaft; this will cause the terminal ends of the arm 25 to sweep around the periphery of the annulus 16 with the detents successively entering inbetween neighbouring tooth formations 18 and riding thereover. If after completion of adjustment of the mechanism the detents are located on top of the tooth formations 18 any vibrations causing rotation of the drive shaft will result in the detents entering into the adjacent tooth depression and thereafter the detents will restrain further rotation of the drive shaft caused by vibration.

Although the above invention has been described in relation to the seat reclining mechanism of the type shown and described in UK patents 1528257 and 1586869 it will be appreciated that the present invention can be used in association with other types of reclining mechanism which rely upon a drive shaft rotating to drive a gear mechanism for relative angular adjustment between the cushion and quab arms. An example of such a reclining mechanism is described in W. German patent specification No. G 8705554.6 The invention described above utilises the raised annulus generated when forming the ring gears in either the squab or cushion arms.

It will be appreciated that if necessary, the annulus may be formed separately and may be defined by different types of tooth formations, for example ridges/grooves.

Claims

1. A seat reclining mechanism including a cushion arm pivotally connected to a squab arm by a gear arrangement, the gear arrangement including a drive shaft drivingly connected to gears for causing relative angular displacement between said arms in response to rotation of the drive shaft, and an arresting means connected between the drive shaft and one of said arms for resisting rotation of the drive shaft caused by vibration.

2. A seat reclining mechanism according to Claim 1, wherein the arresting means includes an arm connected to the drive shaft for rotation therewith, the arm having a resiliently biased detent which engages with an annulus formed on one of said cushion or squab arms, the annulus including toothed formations for co-operation with said detent, the annulus and shaft being co-axial so that rotation of the shaft causes the detent to engage with successive tooth formations around the annulus.

3. A seat reclining mechanism according to Claim 2, wherein the cushion or squab arm having the annulus is formed from metal sheet and includes an integral ring gear which forms part of the gear arrangement, the ring gear being formed by an offset wall portion having a toothed circumference which forms a depression on the inside face of the arm, the offset wall portion also defining the annulus on the outside face of the arm.

4. A seat reclining mechanism according to Claim 2 or 3, wherein the arm comprises a pressing formed from spring steel.

5. A seal reclining mechanism according to Claim 4, wherein said detent comprises a dimple formed in said pressing.

6. A seat reclining mechanism according to Claim 4, wherein said detent comprises a plastics moulding mounted on the terminal end of said arm.

7. A seat reclining mechanism according to any preceding Claim, wherein the gear arrangement includes planetary gears driven by a sun gear.