WO1991013571A1 - Lumbar support - Google Patents

Abstract

An adjustable seat lumbar support is disclosed which includes a first bracket (38) adapted to be fixed on one side frame of the seat, a second bracket (20) including first and second bracket sections (21 and 22), a rocking member (25) intermediate of and pivotably attached to the first and second bracket sections (21 and 22), and adapted to be moved smoothly or stepwise through one or more intermediate positions by operation of adjustment means (30), the first bracket (38) and the rocking member (25) including attachment means (28) adapted to permanently or releasably engage with attachment means on a waist band adapted to extend between the first and second brackets (38 and 20).

Description

LUMBAR SUPPORT This invention relates to lumbar support apparatus and mechanism for seating and relates particularly but not exclusively to such apparatus and mechanisms for motor vehicle seating.

Adjustable lumbar supports are provided in motor vehicles to provide for differing driver requirements and to increase driver or passenger comfort. Such known supports comprise a "waist band" extending between two brackets fixed within and on either side of the frame of a vehicle seat. On one side of the seat frame, the waist band is pivotally attached to the bracket in a fixed position by way of a pivot pin. The pivot pin, which generally includes a nylon or other bush is fixed in pivotal arrangement by an approximately formed plate which encircles the pivot pin and bush and terminates in two parallel spaced apart plates. The waist band is inserted between the plates and fixed by appropriate means such as riveting.

On the other side of the seat frame the waist band is again pivotally attached to a bracket in a manner similar to that described above. The bracket however includes adjustment means to reduce or increase the distance between the ends of the waist band to enable the required adjustable lumbar support. The adjustment is provided by forming the bracket in two parts which are hinged or pivotally fixed on the moveable part which acts as a cam follower. A cam which may be a continuous or stepped cam is operated by an appropriate handle attached to a spindle to permit the desired adjustment. A lumbar support of this known type is described in Australian Patent Application No. 80449/82.

The known prior art lumbar supports are complicated and thus relatively expensive to manufacture. A lumbar support as is described in the above mentioned patent application requires many parts including the fixed bracket, pivot pin and bush, the waist band plate, the waist band, a further waist band plate and associated pivot and bush, a two part bracket pivotably connected to permit appropriate adjustment all in addition to the cam, the cam drive spindle and handle.

In lumbar support devices as have been described above the waist band may be a belt or belt like band of any suitable material. It is customary that waist bands are made of a stiff but flexible material such as a sheet of nylon, polypropylene, polyethylene or the like. It is also customary that a pad of resiliant foam is attached to one side of the waist band to provide additional cushioning to the lumbar region of the seat when fitted with such a device and waist band.

An alternative to the above described mechanisms is that disclosed in PCT Application AU89/00137 to the present Applicant.

It is an object of this invention to alleviate at least some of the aforementioned disadvantages of currently known and used lumbar support devices. Another object of this invention is to provide a lumbar support apparatus which utilizes fewer parts and which is thus cheaper and simpler to manufacture and assemble. A further object of this invention to provide a one piece waist band for a lumbar support apparatus which is simple to manufacture, and, install. The present invention therefore provides in one preferred form an adjustable lumbar support for a seat which comprises a first bracket adapted to be fixed on one side frame of the seat, a second bracket adapted to be fixed to the other side frame of the seat, said second bracket including first and second bracket sections, a rocking member intermediate said first and second bracket sections pivotably attached to said first and second bracket sections at one of its ends, and adapted to be moved smoothly or step wise through one or more intermediate positions between a first and second position by operation of adjustment means, said first bracket and said rocking member including attachment means adapted to permanently or releasably engage with attachment means on a waist band adapted to extend between said first and second brackets. Preferably the adjustment means comprises cam means, advantageously connected to cam drive means disposed within the second bracket and a cam follower means formed, preferably integrally in or on the rocking member. The cam follower is preferably in the form of a deformation or dimple intermediate the ends of the rocking member, which contacts and tracks the cam surface. The cam follower may be biased towards the cam surface by means of a spring attached to the rocking member.

It is presently preferred that the cam means be in the form of a horizontal cam, as opposed to a radial cam. That is, the cam follower will contact a side face of the cam rather than the circumferential face.

The side face of the cam can have any profile which allows for smooth or step wise movement from a first to a second position for varying the degree of lumbar support required.

Preferably the waist band is integrally formed in one piece with attachment means adapted to releasably engage with the attachment means of said first bracket and the attachment means on the rocking member.

The first and second bracket sections are preferably deformed so as to form a pivot recess to engage or receive one end of the rocking member, and thus to allow for pivotal movement of the rocking member as the deformation tracks the cam surface.

Preferably the waist band is integrally formed or moulded from a plastics material such as nylon, polypropylene or polyethylene. In order that the invention may be more readily understood, preferred forms of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is a cross-section view of one lumbar support apparatus constructed in accordance with the present invention.

Figure 2 is an exploded perspective view of the apparatus of Figure 1. Figure 3 is a perspective view of one first bracket in accordance with the present invention.

Referring to the drawings, there is shown an adjustable bracket 20 including first and second bracket sections 21 and 22 respectively each formed in one piece from an appropriately dimensioned metal plate. Rocking member 25, also formed in one piece, is arranged intermediate the first and second bracket sections.

The first and second bracket sections are deformed at one of their respective ends 23 and 24 to define a pivot recess adapted to receive one end 27 of rocking member 25, which enables limited pivotal or rocking motion of the rocking member.

Rocking member 25 includes substantially parallel arms which extend downwardly and terminate in notches or hooks 28. Notches or hooks 28 act as a waist band engaging means.

Orifices 32, 33 and 34 in the first bracket section, rocking member and second bracket section respectively are adapted to receive cam drive means 30 which is connected to cam means 31. Cam means 31, when in position, abuts against second bracket section 22 as shown. The cam drive means 30 may be operated in any manner, for example via a hand wheel external of the seat to enable adjustment by a user. Cam means 31 is profiled, and oriented in a plane which is substantially parallel to the planes of the rocking member and first and second bracket sections.

The motion of the cam means 31 translates to the rocking member 25 by way of a deformation 26 on the rocking member 25 which acts as a cam follower.

Spring 29 ensures that the cam follower is biased towards the cam surface, enabling the cam follower to track the profile of the cam surface. The cam surface is profiled in such a way, be it uniformly increasing or step-wise increasing, that when operated the rocking member 25 is caused to move forwardly and rearwardly (with respect to the cam axis) and increase or decrease the distance between bracket 20 fixed on one side frame of a seat and another bracket 38 fixed on the opposite side frame of the seat. This motion in turn causes the waist belt to provide greater or lesser support in the lumbar region of the seat to which the device is attached. Holes 35 and 36 are adapted to receive fastening means, for example in the form of nut 41 and bolt 42 (only one of each shown) to hold the bracket 20 together, and also for attachment to the seat.

Referring to Figure 3 there is shown a simple fixed bracket for attachment (by means not shown) to the opposite side frame of a seat to the adjustable bracket described above. The bracket 38 is, as with previously described parts, formed in one piece from an appropriately shaped metal plate. The bracket 38 comprises a fixing plate 39 and two substantially parallel side plates 40. Again each of the side plates 40 include downwardly directed arms which terminate in notches 37 as described with respect to bracket 20. The notches again are disposed forwardly (this is to say disposed away from the corresponding bracket on the other side seat frame) to form lock means and enable snap fitting of a waist band appropriately dimensioned. It is thus apparent from the foregoing that the present invention provides a novel, easy to manufacture lumbar support attachment.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An adjustable lumbar support for a seat which comprises a first bracket adapted to be fixed on one side frame of the seat, a second bracket adapted to be fixed to the other side frame of the seat, said second bracket including first and second bracket sections, a rocking member intermediate said first and second bracket sections pivotably attached to said first and second bracket sections at one of its ends, and adapted to be moved smoothly or step wise through one or more intermediate positions between a first and second position by operation of adjustment means, said first bracket and said rocking member including attachment means adapted to permanently or releasably engage with attachment means on a waist band adapted to extend between said first and second brackets.

2. A lumbar support as claimed in claim 1, wherein the adjustment means comprises cam means disposed within or on the second bracket and a cam follower means formed in or on the rocking member.

3. A lumbar support as claimed in claim 2, wherein the adjustment means further includes cam drive means connected to said cam means.

4. A lumbar support as claimed in claim 2 or 3, wherein the face of the cam means is profiled, and oriented in a plane which is substantially parallel to the planes of the rocking member and the first and second bracket sections.

5. A lumbar support as claimed in claim 4, wherein the cam follower means is in the form of a deformation or dimple intermediate the ends of the rocking member, which contacts and tracks the profiled face of the cam means on operation of the adjustment means.

6. A lumbar support as claimed in any one of the preceding claims, wherein the waist band is integrally formed in one piece with attachment means adapted to releasably engage with the attachment means of said first bracket and the attachment means on the rocking member.

7. A lumbar support as claimed in any one of the preceding claims wherein the first and second bracket sections are deformed so as to form a pivot recess to engage or receive one end of the rocking member to allow for pivotal movement of the rocking member.

8. An adjustable bracket for a seat lumbar support which comprises first and second bracket sections, a rocking member intermediate said first and second bracket sections pivotably attached to said first and second bracket sections at one of its ends, and adapted to be moved smoothly or step wise through one or more intermediate positions between a first and second position by operation of adjustment means, said rocking member including attachment means adapted to permanently or releasably engage with attachment means on a lumbar support waist band.

9. A bracket as claimed in claim 8, wherein the adjustment means comprises cam means disposed within or on the adjustable bracket and a cam follower means formed in or on the rocking member.

10. A bracket as claimed in claim 9, wherein the adjustment means further includes cam drive means connected to said cam means.

' 11. A bracket as claimed in claim 9 or 10, wherein the face of the cam means is profiled and oriented in a plane which is substantially parallel to the planes of the rocking member and the first and second bracket sections.

12. A bracket as claimed in claim 11, wherein the cam follower means is in the form of a deformation or dimple intermediate the ends of the rocking member, which contacts and tracks the profiled face of the cam means on operation of the adjustment means.

13. A bracket as claimed in any one of claims 8 to 12 wherein the first and second bracket sections are deformed so as to form a pivot recess to engage or receive one end of the rocking member to allow for pivotal movement of the rocking member.

14. A lumbar support including the bracket of any one of claims 8 to 13.

15. A lumbar support as claimed in any one of claims 1 to 7 wherein the waist band is integrally formed in one piece from a plastics material.

16. A lumbar support as claimed in claim 15, wherein the plastics materials is polypropylene, polyethylene or nylon.

17. A vehicle seat including the lumbar support of any one of claims 1 to 7 or any one of claims 14 to 16.