EP1496770A1

EP1496770A1 - Backrest or backrest section for a chair, in particular for a wheelchair

Info

Publication number: EP1496770A1
Application number: EP03727323A
Authority: EP
Inventors: Rodney William Palmer
Original assignee: Performance Health Products Ltd
Current assignee: Performance Health Products Ltd
Priority date: 2002-04-19
Filing date: 2003-04-17
Publication date: 2005-01-19
Also published as: HK1061958A1; DK1354538T3; PT1354538E; ATE326154T1; EP1354538B1; EP1354538A1; AU2003233989A1; DE60211477D1; ES2263744T3; WO2003088783A1; DE60211477T2

Abstract

The backrest (10) with wing pads (14) is intended for individuals suffering from spinal deformities, such as scoliosis, or muscular atrophy. The backrest can be used in particular with wheelchairs. The backrest comprises a back support (13) and the wing pad (14) comprises a backing plate (23). Back support (13) and backing plate (23) are connected by a hinge (15). Adjusting means (17) allow to adjust the angle of the wing pad (14) with respect to the back support (13). <IMAGE> <IMAGE>

Description

Backrest or backrest section for a chair, in particular for a wheelchair

This invention relates to a backrest or a backrest section with at least one adjustable wing.

A wheelchair generally has a seat and a backrest that are supported by a pair of side frames. Backrest posts extend upwardly from the rear end of the side frames of the wheelchair and turn rear war dly away from the backrest to form handles. Some wheelchairs have collapsible struts positioned between the side frames to maintain the side frames in a parallel, spaced apart orientation when the chair is occupied by a user. When the struts are collapsed, the side frames move together to allow for easy transportation or storage of the wheelchair. Typically the seat and the backrest of such collapsible wheelchairs are constructed from flexible material that easily folds when the wheelchair is collapsed. However, the flexible material of the seat and backrest does not provide optimum support or comfort for the occupant. For this reason contoured backrests have been developed to provide improved support for individuals requiring special support, such as those having spinal deformities or muscular atrophy.

GB 1 512 028 shows an automobile seat with symmetrically movable lateral flaps. These flaps are separate parts hinged to the backrest. This seat is quite complicated and expensive to manufacture. The same holds true to the automobile seat according to US 4,500,136. Also the seat according to US 6,254,186 is described as especially suited as vehicle seat for aircraft, waterborne vehicles and land vehicles. The seat comprises an adjustable lumbar support with a flexible band having a plurality of pleats which in response to a motor drive change the longitudinal tension in the flexible band to adjust the lumbar support given to the driver.

All these seats which are designed for automotive vehicles are not well suited for the users of wheelchairs.

WO 96/07344 discloses a backrest to be employed in conjunction with a wheel chair or the like for people who require postural support. The back rest comprises a substantially rigid shell having a back portion and side portions. Attached to the rigid shell is a pair of flexible side support panels. Each side panel is partly divided into an upper, a middle and a lower portion which are individually adjustable by knobs mounted on the outside of the rigid shell and acting on the associated portion of the flexible side support panel. This backrest has the disadvantage of requiring different parts of rigid and flexible sheet material and having twelve knobs awkwardly protruding outward from the rigid shell.

A very practical contoured backrest is sold under the name "N-TRAK". This backrest is available in different forms, namely as sports backrest, standard backrest, high backrest and segmented backrest. All these backrests have on the rear side in the middle a rail which permits hight-adjustable connection to a support. From this support extend two lateral arms having at their end a quick connecting and release device for connecting the backrest assembly to the wheelchair. For this purpose the side frames of the wheelchair are provided with adapters for cooperation with these connecting and release devices. The backrest or each segment of the backrest comprises a back support consisting of a shell of plastic material having a cylindrical curvature. Straps or belts extend from one side of the back support to the other side and to the rear of the back support. These straps can be tensioned from the rear side of the backrest and locked in the desired position. Tensioning the straps elastically deforms the back support. Located over the straps is a cushion. In addition, a cover encloses the assembly both on the front and the back.

In the WO 99/17636 also a modular backrest system for a wheelchair is described. This backrest system also can be removably attached to the backrest posts of the wheelchair. This backrest can be provided, if desirable, with one or more wings. Each wing includes a backing plate and a cushion attached to the forwardly presented face of the backing plate. Each wing includes a pair of L-shaped support posts. These support posts can be inserted into openings of the back support of the backrest and arrested with screws in the desired position. Therefore, a user suffering, for example from scoliosis, will be laterally supported by one or more wings.

The described backrest with wings has the disadvantage that the wings are separate units and require a relatively complicated attachment means. The attachment means permit only a linear adjustment. An angular adjustment is not possible. In addition, the backrest with the wing and the protruding parts of the L- shaped support posts does not have a nice appearance. This lets the user appear more invalid than he in reality may be. This may have undesirable psychological consequences for the user. There is also the danger that the arm of the user gets entrapped between the wings.

EP 0 328 137 shows an automobile seat with a backrest comprising a frame having two spaced supporting bars carrying a back support consisting of one piece of elastically deformable plastic sheet material. This piece of sheet material comprises a convex central portion and two side walls or lateral flaps extending laterally outward from the central portion. Hinges are provided at the spaced supporting bars. If the back of the driver presses against the central portion both flaps are symmetrically and simultaneously moved inward to give lateral support to the body of the driver. This backrest is not suitable for the users of wheel chairs, because it does not give firm support to the body and the lateral flaps can not be positioned individually and permanently according to the requirements of the user.

Therefore it is an object of the invention to provide a backrest which in particular is suitable for people who require postural support, as some users of wheelchairs do. In particular it is the object of the invention to provide a backrest on which the back support and the backing plates for the adjustable wings consist of only one piece of material, but permit individual adjustment of the wings. The adjusting means should not have knobs protruding from rear of the back support.

According to the invention the backrest is characterised in that each wing is provided with an adjusting screw device located in substantially horizontal position and parallel to the back support. This permits individual angular adjustments of the wing parts and has the advantage of a compact design with no knobs protruding from the rear of the backrest preventing its covering with a cover of fabric or other suitable material.

The hinge may be formed by folds in the sheet material. The use of such sheet material provides for low manufacturing cost.

A preferable embodiment of the backrest according to the invention comprises a back support and one or more belts for supporting the back of the user, each belt being attached with one end at one lateral portion of the back support and extending on the front side of the back support to an opposite lateral portion of the back support from where its turned around to an adjusting device. This backrest is characterised in that the belt is elastically stretchable or comprises at least one elastically stretchable section. The adjusting device is preferably a cable binder attached to the back support and engaged an eye attached to the end of belt.

Embodiments of the invention is shown in the drawings:

Figure 1 shows a schematical drawing of the back support of the backrest as seen from the front side with one of the four belts attached,

Figure 2 shows a view from the top of the back support shown in figure 1,

Figure 3 shows enlarged a cross-section along the line III-III in figure

1 with the adjusting means for the wings added,

Figure 4 shows a backrest having two backrest sections constructed substantially as shown in figures 1 to 3,

Figure 5 shows a backrest from the back having three backrest sections as shown in figure 4.

In figure 1 the cushion and the cover of the backrest 10 are not shown, but in figure 2 the cushion 11 is represented by a dotted line. It is an advantage of the backrest construction shown that it may have several wings 14 on each side while allowing foam cushion 11 and fabric cover (not shown) to bridge the divisions between the wings 14 to conceal the divisions and thus blending any difference arising from different orientation of the upper and lower wings 14. This feature also prevents an accidental entrapment of the occupants arms.

As can be seen, the back support 13 and the backing plates 23 of the wings 14 are one piece formed of a sheet of preferably thermoplastic sheet material. However, they could also be made by moulding plastic material. They could even be formed of a resilient metal sheet. In the present embodiment the hinged portion is provided by folds 15 in the sheet material. The hinge portion 15 is provided by a deformable, for example thinned section, and allows pivoting of each wing 14 about a substantially determined axis. This feature also allows the backrest to be reduced in width to fit exactly into the available space within a wheel chair or similar structure.

An adjusting screw or tensioning device 17, as shown in figure 3, serves as adjusting means for adjusting the angle of the wing 14 with respect to the back support 13. The screw tensioning device 17 substantially comprises a screw 19 and a bracket 21 in form of a U. The screw 19 is mounted in substantially horizontal position and parallel to the back support 13. The bracket 21 is pivotally mounted by a screw 41 on the backing plate 23 of the wing 14. In figure 2, where the screw tensioning device has been omitted, the hole 25 for mounting the bracket 21 is seen. As figure 3 shows, the screw 19 has preferably a female hexagon head 26 to permit turning the screw 19 with the socket wrench. The thread 27 of the screw 19 is threaded into a tapped hole 29 of the bracket 21. A screw cap 31 is mounted on the screw 19 to prevent turning the screw 19 out of the tapped hole 29. Instead of a washer a cylindrical piece 33 with a hole 35 is provided. The screw head 26 and the piece 33 are received in a channel 37 on the rear side of the back support 13. Part of the screw 19 extends in a channel 39 of the back support 13. The bracket 21 is received in a channel 43 of the wing 14. On the backing plate 23 of the wing 14 a cover plate 24 (only shown in figure 3) covers the region of the bracket 21 and the screw 19 in the hinge portion 15 to prevent them contacting the cushion 11.

The backrest shown in figure 1 is provided with four wings 14. Two are located at the thoriac level and two are located at the pelvic level. As each wing 14 can be adjusted independently a multitude of symmetrical and assymetrical shapes can be created to suit the users size, shape and postural requirements. As described later this lateral profiling can be combined with vertical profiling achieved by individual tensioning of the belts 51.

As will the evident from figures 2 and 3, tightening of the screw 19 will move the wing 14 in direction of the arrow 45 around the hinge 15. On the contrary, losening the screw 19 will permit the wing 14 to return again in direction opposite to the arrow 45.

The backrest as shown in the drawing may be provided with one or more belts or straps 51 for supporting the back of the user. The backrest shown in figure 1 is provided with four belts, but only one belt 51 is shown. The belt 51 is attached with the hook 53 at one lateral portion of the back support 13 and extends on the front side of the back support 13 to a hook 53 of the opposite lateral portion. There the belt is turned around in direction to an adjusting device 55. This provides for lever effect so that only half the force is required to tension the belt 51. The belt 51 is either elastically stretchable or comprises at least one elastically stretchable section 57. As shown in figure 2, the elastically stretchable section 57 is connected to a loop 58 of the belt. The partial elastication provides for a wide range of responses but also for a limit to the length of extension of the belt 51. The adjusting device 55 is preferably a cable binder engaged to an eye 59 attached to the end of the belt 51. The cable binder 55 provides additional leverage. The back support 13 is dimensioned strong enough so that it does not perceptably flex in response to tensioning the belt 51.

It will be obvious to the man skilled in the art that the invention is applicable to different sizes and forms of the backrest with different numbers of wings 14 and belts 51. The invention may also be applied to segmented backrests as this is shown in figures 4 and 5.

Claims

Patent claims

1. A backrest or backrest section for a chair, in particular for a wheelchair, comprising a back support (13), backing plates (23) for adjustable wings (14), said back support (13) and said backing plates (23) consisting of one piece of material having deformable sections forming hinge portions (15) between the back support (13) and the backing plates (23) for the adjustable wings (14), characterised in that each wing (14) is provided with an adjusting screw device (17) located in substantially horizontal position and parallel to the back support (13).

2. The backrest or backrest section as claimed in claim 1, characterised in that the adjusting screw device (17) comprises a screw (19) and a bracket (21) having a tapped hole (29) receiving the thread (27) of the screw, said screw (19) being mounted in substantially horizontal direction and parallel to the back support (13) and said bracket (21) being pivotally mounted on the backing plate (23) of the wing (14).

3. The backrest or backrest section as claimed in claim 1 or 2, characterised in that channels (37,39,43) are formed in the back support (13) and the backing plate (23), said channels receiving the screw (19) and the bracket (21).

4. The backrest as claimed in one of the claims 1 to 3, characterised in that a screw cap (31) is mounted on the screw thread (27).

5. The backrest or backrest section as claimed in any of the claims 1 to 4, characterised in that a cover plate is provided on the backing plate covering the bracket (21) and the screw (19).

6. The backrest or backrest section as claimed in one of the claims 1 to 5, characterised in that the back support (13) together with the backing plate (23) of the wing (14) are formed of plastic sheet material.

7. The backrest or backrest section as claimed in one of the claims 1 to 6, characterised in that the hinge (15) is formed by folds in the sheet material.

8. A backrest or backrest section comprising a back support (13) and one or more belts (51) for supporting the back of the user, each belt (51) being attached at one lateral portion of the back support (13) and extending on the front side of the back support (13) to the opposite lateral portion thereof from where it is deflected and has its end connected to an adjusting device (55), characterised in that the belt (51) is elastically stretchable or comprises at least one elastically stretchable section (57).

9. A backrest or backrest section as claimed in claim 8, characterised in that the adjusting device is a cable binder (55) attached to the back support (13) and engaging an eye (59) attached to the end of the belt (51).

10. A backrest or backrest section as claimed in claim 8 or 9, characterised in that the back support is dimensioned such that it practically not deformed by the tensioning of the belt (51).

11. A backrest or backrest section as claimed in one of the claims 1 to 10, characterised in that it comprises wings (14) both in the thoriac and the pelvic region.

12. A backrest or backrest section as claimed in one of the claims 1 to 7 with the features of one of the claims 8 to 11.