GB2213869A

GB2213869A - Seat reclining mechanism

Info

Publication number: GB2213869A
Application number: GB8729772A
Authority: GB
Inventors: Clifford Aiken
Original assignee: IHW Engeneering Ltd; AJC Johnson Controls Ltd
Current assignee: AJC Johnson Controls Ltd
Priority date: 1987-12-21
Filing date: 1987-12-21
Publication date: 1989-08-23
Anticipated expiration: 2007-12-21
Also published as: GB8729772D0; GB2213869B

Abstract

In a seat reclining mechanism which includes a cushion arm 14 pivotally connected to a squab arm 12 by a planetary gear arrangement, the planetary gear arrangement including a pair of side by side ring gears, one ring gear being secured to the squab arm and the other being secured to the cushion arm, and a sun gear in driving connection with both ring gears via planetary gears, biasing means 32 are provided acting to urge the ring gears apart in a radial direction so as to take up play in the mechanism. The biassing means comprises a spring element 32 with supports 36, 37 the spring acting on the curved surface 30 of the support arm 12. <IMAGE>

Description

SEAT RECLINING MECHANISM The present invention relates to a seat reclining mechanism.

In our U.K. Patents 152835 and 1586869 we disclose a seat reclining mechanism which includes a cushion arm pivotally connected to a squab arm by a planetary gear arrangement. The planetary gear arrangement includes pair of side by side ring gears, one being secured to the squab arm and the other being secured to the cushion arm.

A sun gear is provided which is in driving connection with both ring gears via a plurality of planet gears. The pitch of teeth in each of the ring gears is different so that rotation of the planet gears causes a relative rotation between the ring gears.

The planet gears float and it is necessary for there to be an acceptable amount of tolerance between the gears in order to able smooth operation. Unfortunately such tolerance also results in pivotal play between the squab and cushion arms.

In accordance with the present invention such play is substantially reduced or eliminated by the application of a resilient radially directed bias on at least one of said ring gears. This has the effect of causing said one ring gear to be urged in a radial direction to eliminate the tolerances between the ring gears and planet gears and sun gear along said radial direction. Accordingly pivotal play between the squab arm and cushion arm is substantially reduced or eliminated.

Smooth operation of the reclining mechanism is not affected since rotation of the sun gear is not impaired by the biased ring gear.

Preferably the bias means for creating said radially directed bias acts on both ring gears to resiliently bias them in opposite radial directions.

Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which: Figure 1 is a side view of a seat reclining mechanism according to the present invention; and Figure 2 is a sectional view along line II-II in Figure 1.

In the drawings there is shown seat reclining mechanism 10 including a squab arm 12 pivotally connected to a cushion arm 14 by a planetary gear mechanism 16. In use the seat reclining mechanism 10 is located at one side of a seat, the cushion arm 14 being attached to the cushion frame (not shown of the seat and the squab arm 12 being attached to the squab or back frame (not shown) of the seat. Preferabl a similar seat reclining mechanism 10 is located at the opposite side of the seat.

The gear mechanism 16 is preferably of the type described in either our U.K. Patent 1528357 or 1586869.

Reference should be made to either of these Patents for a more detailed disclosure of the construction and operation of the gear mechanism 16.

In brief, the gear mechanism 16 includes a sun gear 20 and a plurality of planetary gears 22. In our U.K.

Patents 1528357 and 1586869 four planet gears are shown but it will be appreciated that more or fewer than four planet gears may be used.

A ring gear 24 is formed in the squab arm and a ring gear 25 is formed in the cushion arm. Both of these gears are conveniently formed by a pressing operation. The pressing operation also offsets a wall portion 12a and 14a in the squab arm and cushion arm respectively to define a housing chamber 27 for the gear mechanism 16.

The ring gears 24, 25 have a different number or pitch of teeth and both gears 24, 25 are in common mesh with the planet gears 22. Accordingly rotation of the sun gear 20 causes rotation of the planet gears 22 and due to the different pitch of ring gears 24, 25, the ring gears 24, 25 are caused to rotate at different speeds thereby causing relative rotation therebetween.

The planet gears 22 are not secured to either wall portion 12a, 14a and are free to float at least in a radial direction.

The squab arm 12 is provided with a curved surface 30 preferably defined by the bottom edge of the squab arm. The curved surface 30 is concentric with the ring gear 24.

Biasing means are provided preferably in the form of a curved spring element 32, for resiliently engaging the curved surface 30 to urge the ring gear 24 in a given radial direction.

The curved spring element 32, preferably formed from a spring steel wire, has a pair of arms 33, 34 each of which press against the surface 30. The arms 33, 34 are held captive by a pair of rivets 36 located on the cushion arm 14. An abutment 37 also located on the cushion arm 14 is provided to engage the central portion of the spring element 32 and thereby maintain it in a state of compression.

Preferably, in assembly, the abutment 37 is mounted on the cushion arm 14 after insertion of spring element 32 between the rivets 36 and the surface 30. This enables the spring element 32 to be inserted in a relaxed state.

The spring element 32 is then compressed and the abutment is mounted.

Since the spring element 32 is mounted on the cushion arm 14, its bias effect is to urge the ring gears 24, 25 in opposite radial directions. This effect thus causes the radially opposed sides of ring gears 24, 25 to move toward one another to mesh tightly with the planet gears 22 located therebetween.

Claims

C L A I Nl 5

1. A seat reclining mechanism including a cushion arm pivotally connected to a squab arm by a planetary gear arrangement, the planetary gear arrangement including a pair of side by side ring gears, one ring gear being secured to the squab arm and the other being secured to the cushion arm, and a sun gear in driving connection with both ring gears via planetary gears, and biasing means acting to urge the ring gears apart in a radial direction.

2. A mechanism according to Claim 1 wherein the biasing means acts on at least one of the ring gears.

3. A mechanism according to Claim 2 wherein the biasing means acts on both ring gears to resiliently bias them in opposite radial directions.

4. A mechanism according to Claim 3 wherein one of the arms is provided with a curved outer surface concentric with its associated ring gear and the biasing means is mounted on the other of the arms and slidably engages said curved outer surface.

A \ mechanism according to claim 4 wherein the biasing means comprises a curved spring element.

6. A mechanism according to Claim 5 wherein the cured spring element has a pair of arms each of which press against said curved outer surface. the spring element being mounted on the other arm by a pair of spaced apart rivets and being held in a compressed state by an abutment located between said rivets.

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