WO1998042234A1

WO1998042234A1 - Backrest with integral inflatable lumbar support

Info

Publication number: WO1998042234A1
Application number: PCT/US1998/005446
Authority: WO
Inventors: Frank L. Roberts
Original assignee: Bio-Support Industries Ltd.
Priority date: 1997-03-21
Filing date: 1998-03-23
Publication date: 1998-10-01
Also published as: CA2284786A1; AU6571298A

Abstract

A backrest (10) including a shell frame (12) and an upholstered finish includes a bladder (30) with an inflation control comprising manually operable squeeze pump (34) and push-button valve (38). The inflation control (32) is disposed entirely within the upholstered finish in a manner so as to be unlikely to be operated by inadvertence.

Description

BACKREST WITH INTEGRAL INFLATABLE LUMBAR SUPPORT

Field of Invention

This invention relates to backrests. It particularly relates to backrests that incorporate an inflatable lumbar support.

Background of Invention

Backrests such as those contemplated by the instant invention are described in U.S. patent 4,556,254, commonly assigned herewith, the contents of which are incorporated herein by reference thereto. Such backrest may be entirely portable, for use with most seating arrangements likely to be encountered by a user, or it may form the backrest of a chair.

It is known to provide a lumbar pad which may be secured to the forward surface of the backrest, one such lumbar pad being the subject of U.S. Design Patent D 311 ,295, commonly assigned herewith. It is also known to provide lumbar supports which comprise a bladder disposed within the upholstered finish of a backrest and which includes bladder inflation control means comprising a manual pump, a hose and a valve for exhausting air from the bladder, wherein the manual pump and valve are disposed externally to the backrest, for example as shown on the following U.S. patents: 3,974,827 (Bodan)

4,516,568 (Baxter et al) 4,518,200 (Armstrong) 4,789,202 (Alter) 5,314,235 (Johnson) The externally disposed bladder inflation control means is susceptible to being damaged, and is aesthetically unappealing.

It is known to provide an inflatable bladder in different articles, for example exercise shoes, wherein inflation control means is disposed within the article. Generally speaking, such bladders and the pumps used for their inflation are relatively small, and the pumps and valves are easily disposed in a portion of the article in which they are not susceptible to inadvertent operation. In contrast, backrests are intended to support the back of a user over most of their forwardly disposed surface, and the rearwardly disposed surface, at least in the case of a freely transportable backrest, is likely to come into contact with many different types of support structures over much of its area. Given that a bladder useful for the present purposes is likely to have a volume of about 1.5 litre when inflated, the pump is required to have a reasonable capacity and will present a relatively large surface area. Given also that a user of the backrest will not uncommonly shift positions, the pump is subject to inadvertent operation, as is a push button type of pressure venting valve.

It is an object of this invention to provide backrests having a bladder type of lumbar support and manual pressure adjustment means which is wholly contained within the upholstered finish of the backrest.

It is another object of this invention to provide backrests with the self-contained inflatable lumbar supports which are aesthetically pleasing.

Summary of the Invention

In accordance with a broad aspect of this invention, in a backrest including a shell frame having in transverse medial section a shallow concave form with a margin therearound, an upholstered finish covering the shell including a foam cushion layer and a fabric cover therefor; an inflatable bladder disposed between the shell and the fabric cover to provide a lumbar support over medial portions of the backrest when inflated, and bladder inflation control means including a manual pump for inflating the bladder and push button valve means for exhausting the bladder into the surrounding atmosphere; the inflation control means is nestled in the foam cushion in portions thereof intermediate the bladder and the margin, and totally enclosed by the cover. Given the shallow concavity of the shell frame, the portion of the backrest in which the inflation control means is disposed will normally have a partially laterally inwardly facing component, thereby reducing the forward thrust component to which the inflation control means is exposed in normal use of the backrest. More importantly, as the bladder is inflated, it will urge the back of a user away from the portion of the backrest in which the inflation control means is disposed. Moreover, in a frame such as that described in the above mentioned U.S. patent 4,556,254, the width of the frame increases adjacent the lumbar area in wings, and the lumbar area will have a shallow convexity in vertical cross-section. Preferably the manual pump at least of the inflation control means will be disposed adjacent the margin of a wing somewhat inferior to the zone of maximum forward thrust of the convexity, wherein the backrest has a rearwardly sloping component. Each of these factors individually tends to reduce the load which is applied to the backrest, when in normal use, in the vicinity of the inflation control means, and thereby reduce the likelihood of the inadvertent actuation of the pump or the push button valve means.

The fabric cover will normally comprise a thin jersey knit material, optionally bonded to a thin layer of foam material to provide greater structural integrity, and such fabric is soft and pliable. As described in greater detail in U.S. patent 4,556,254 aforesaid, the fabric cover of the backrest is normally stretched between the margins, so as to be spaced apart from the foam cushion layer, and thereby de-localize the pressure on the back of a user of the backrest. Where, as herein, the inflation control means is disposed beneath the fabric cover of the backrest, the stretched cover will tend to reduce the compressive load to which the inflation control means is subject when the backrest is in its normal use, while at the same time creating some difficulty in defining the area at which manual pressure is intended to be applied to bring about the desired operation of the inflation control means. Suitably and preferably, the cover is provided in portions overlaying at least the pump of the inflation control means with a domed, resile load transfer port, which has the effect of transferring low pressure loads typically having a value up to about 1 to 2 kg/sq cm to the underlying foam cushion. At higher loads such as will be applied when it is desired to actuate the pump to inflate the bladder, and actuate the push button valve means, the resile load transfer port will deform to permit such actuation. The domed, resile load transfer port is generally in the form of an outwardly facing dome, and will include a surrounding flange, the flange serving to secure the port to the cover, and to transfer to the cover small loads applied to the resile dome. The dome further serves to delimit the area beneath which the concealed pump and the push button valve means are located, to facilitate their operation by the user, even where relying solely upon tactile cognition, and to retain the smart appearance of the port without relying upon any biasing force generated by the underlaying inflation control means or other external agency.

The foregoing objects and aspects of the invention, together with other objects, aspects and advantages thereof will be more apparent from a consideration of the following description of the preferred embodiment thereof taken in conjunction with the drawings annexed hereto.

Brief Description of the Drawings In the Drawings Fig. 1 shows in perspective view from the front left side an illustrative backrest in accordance with the invention;

Fig. 2 is a vertical medial cross-section through the backrest of Fig. 1 , with the bladder in an uninflated condition and the cover partially broken away to reveal the underlaying bladder inflation control means;

Fig. 3 is similar to Fig. 2, but shows the bladder fully inflated;

Fig. 4 is a transverse cross-section on line 4-4 of Fig. 2;

Fig. 5 is a transverse cross-section on line 5-5 of Fig. 3;

Fig. 6 is an enlarged front elevation of the load transfer port; Fig. 7 is a cross-section on line 7-7 of Fig. 6; and

Fig. 8 is a portion of the inflation control means shown in perspective view.

Description of the Preferred Embodiment

Referring now to the drawings in detail, a backrest with an integral lumbar support adjustment is identified generally therein by the numeral 10. Backrest 10 comprises a thin, shell like frame 12 having in horizontal cross-section a concavity and in medial vertical cross-section a shallow S shape which generally conforms to the curvature of the spine of the average person extending between the 2nd and the 6th vertebrae, with a zone of maximum forward thrust 14 in the lumbar region. Backrest 10 is formed with lateral wing portions 16 which increase the width of the backrest over the lower portions thereof, which wing portions are defined in part by lateral margins 18. Frame 12 is covered by an upholstered finish 20 comprising a foam layer 22 and a cover layer 24 suitably of jersey knit fabric stretched tightly over lateral margins 18 so as to be spaced apart somewhat from the underlaying forward facing surfaces of the backrest in the lumbar area, which extends somewhat above and below the zone maximum forward thrust 14 over medial portions of the frame. Backrest 10 includes an inflatable bladder 30 disposed on frame 12 so as to extend over the lumbar area of the backrest. Suitably, the bladder 30 is disposed between the frame 12 and the foam layer 22 of the upholstered finish 20.

Backrest 10 further includes inflation control means 32 which comprises a rubber bulb 34 having an outlet 35 which connects to bladder 30 by means of air hose 36. Inflation control means 32 also includes a control valve 38 disposed in arm 40 intermediate bulb 34 and outlet 35, generally at right angles to the top to bottom axis of bulb 34. Arm 40 includes at one end thereof a barb 42 which provides a convenient means for the inflation control means to be anchored to frame 12 using a suitably placed opening therein (not shown). Control valve 38 is of a generally known push button type having an actuating head 44 which is forwardly biased by a spring (not seen). The head 44 is surrounded by a shield which takes the form of a plurality of fingers 45, the tips of which are at or marginally forward of the forward surface of the actuating head 44 of the push button valve. A flexible fabric load transfer port 48 is secured to cover layer 24 in general register with the underlaying inflation control means 32. Port 48 comprises a central portion 50 which is in the form of a resile dome generally complementary to portions of bulb 42 overlaid thereby, the central portion being surrounded by a flange portion 52 through which port 48 is secured to cover layer 24, as by sewing. Suitably, the flange portion 52 is enlarged at its upper end 54, so as to overlay the actuating head 44 of the push button, with a smaller centrally raised resile dome 56 being disposed in alignment with the actuating head. Suitably, port 48 has a composite structure comprising an outer layer 60 of nylon Spandex® fabric and an inner supporting layer 62 of unwoven polyester fabric, and is thermally set to provide the stable, resile, domed central portions 50,56.

Inflation control means 32 is disposed on a wing portion 16 of the backrest 10 intermediate bladder 30 and an adjacent lateral margin 18, with bulb 42 being mostly disposed below the zone 14 of maximum forward thrust.

In using backrest 10, bladder 30 is inflated to a desired degree by applying pressure to bulb 42 through the centrally domed portion 50 of port 48, as by pushing with finger tips. The centrally domed portion 50 assists a user in locating underlaying bulb 42, and it also provided an elastic memory to return the central portion to its relatively stable domed condition upon release of finger pressure, so as to retain a smart appearance. In addition, the centrally domed portion is capable of withstanding an appreciable force before it undergoes a resilient deformation, and together with the natural resistance to deformation offered by bulb 42, it is found that the forces to which port 48 is adventitiously exposed when backrest 10 is in normal use are unlikely that bulb 42 will be actuated inadvertently so as to cause bladder 30 to inflate.

A pressure applied broadly to port 48 in the vicinity of domed portion 56 will tend to be transmitted to frame 12 through fingers 45 and arm 40, and the control valve 38 will only be actuated by a localized force applied directly to the actuating head 44 of the valve, the spacing between the fingers 45 permitting the cover layer 24 to undergo a local deformation. The actuation valve 38 in this manner will permit the controlled exhaustion of air from bladder 30 as desired by a user of backrest 10. The inflation of bladder 30 will bend to localize the transfer of pressure between the back of a user and the lumber zone of the backrest 10 to transversely medial portions of the backrest. As a corollary of this, the forces to which the inflation control means 32 are exposed during normal use of the backrest 10 when bladder 30 is inflated are reduced, whereby it becomes even less likely that the inflation control means will be operated by inadvertence.

It will be apparent that many changes may be made to the illustrative embodiment while falling within the scope of the invention, and it is intended that all such changes be covered by the claims appended hereto.

Claims

1. In a backrest including a relatively rigid shell having a margin therearound and an upholstered finish covering said shell including a foam cushion layer and a fabric cover, an inflatable lumber support bladder disposed between said fabric cover and said shell; bladder inflation control means including a manual pump disposed between said fabric cover and said shell intermediate said bladder and said margin adjacent to said bladder, and an air hose connecting said bladder inflation control means to said bladder.

2. A backrest as defined in Claim 1 including a resile domed port secured to said fabric cover in overlaying register with said manual pump.

3. A backrest as defined in Claim 2 wherein said resile domed port includes a flange portion therearound which serves to transfer small loads applied to said port to said foam cushion layer.

4. A backrest as defined in Claims 1 , 2, or 3 wherein said inflation control means includes a push button valve for deflating said bladder when actuated.

5. A backrest as defined in Claim 4 wherein said push button valve includes an actuation head encircled by a shield.

6. A backrest as defined in Claim 5 wherein said shield is in the form of a plurality of fingers.

7. A backrest as defined in Claim 5 wherein said flange of said resile domed port is enlarged at one end thereof, and wherein a second resile dome portion is provided on said enlarged flange to overlay said actuation head.

8. A backrest as defined in Claim 2 wherein said resile dome port is fabric.

9. A backrest as defined in Claim 7 wherein said resile dome port is fabric.

10. A backrest as defined in Claim 2 wherein said frame is concave in transverse cross-section in portions thereof over which said bladder is disposed.

11. A transportable backrest comprising a rigid shell defined in part by lateral margins, a forward face having a top to bottom axis and a concavity in medial transverse cross-sections thereof; an inflatable lumbar support bladder secured to said forward face in medial portions thereof; an upholstered finish comprising a foam cushion layer and a fabric cover enveloping said frame; bladder inflation control means including a manual pump disposed between said cover and said forward face of said frame intermediate said bladder and an adjacent lateral margin; and an air hose interconnecting said bladder and said bladder inflation control means.

12. A backrest as defined in Claim 11 including a resile domed port secured to said fabric cover in overlaying register with said manual pump.

13. A backrest as defined in Claim 12 wherein said resile domed port includes a flange portion therearound which serves to transfer small loads applied to said port to said foam cushion layer.

14. A backrest as defined in any of Claims 1 1-13 wherein said inflation control means includes a push button valve for deflating said bladder when actuated.

15. A backrest as defined in Claim 14 wherein said push button valve includes an actuation head encircled by a shield.

16. A backrest as defined in Claim 15 wherein said shield is in the form of a plurality of fingers.

17. A backrest as defined in Claim 12 wherein said flange portion of said resile domed port is enlarged at one end thereof, and wherein a second resile dome portion is provided on said enlarged flange to overlay said actuation head.

18. A backrest as defined in Claim 12 wherein said resile dome port is fabric.

19. A backrest as defined in Claim 17 wherein said resile dome port is fabric.

20. A backrest as defined in Claim 17 wherein said inflation control means is secured to said frame by a barb.