AU724957B2

AU724957B2 - Tiltable wheelchair

Info

Publication number: AU724957B2
Application number: AU64375/96A
Authority: AU
Inventors: Brian John Salfinger; Paul Francis Salfinger
Original assignee: Lendal Pty Ltd
Current assignee: Lendal Pty Ltd
Priority date: 1995-08-30
Filing date: 1996-08-30
Publication date: 2000-10-05
Anticipated expiration: 2016-08-30
Also published as: AU6437596A

Description

I. P/00/011 28/5/91 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT .b* Name of Applicant: Actual Inventor(s): Address for service is: LENDAL PTY LTD PAUL FRANCIS SALFINGER and BRIAN JOHN SALFINGER WRAY ASSOCIATES 239 Adelaide Terrace Perth, WA 6000 Attorney code: WR Invention Title: "Tiltable Wheelchair" Details of Associated Provisional Application No(s): PN5131 The following statement is a full description of this invention, including the best method of performing it known to me:- -2- THIS INVENTION relates to chairs. More particularly, the invention relates to chairs of the type which have an occupant supporting portion which is tiltable so that the occupant of the chair can be supported in various positions, generally between an upright position and a rearmost reclined position.

The invention has been devised particularly, although not solely, for wheelchairs and other forms of mobile chairs.

Some wheelchairs have an occupant supporting portion which is mounted on a chassis structure in a manner which allows the occupant supporting portion to be tilted about a generally horizontal axis transverse to the direction of travel of the wheelchair. The occupant supporting portion, which comprises a seat and backrest, can be selectively tilted into one of various positions between a generally upright position and a rearmost inclined position according to the requirements of the occupant of the wheelchair. A problem associated with such wheelchairs is that tilting of the occupant supporting portion causes a shift in the 15 centre of gravity of the combination of the wheelchair and occupant therein which can lead to instability when the occupant supporting portion is inclined into its rearmost reclined position. The instability may not necessarily be a problem when the wheelchair is stationary or travelling over generally flat surfaces but it can be of concern when traversing irregular surfaces and obstacles such as kerbs.

S- It would be advantageous to provide a chair which can compensate for a shift in the centre of gravity upon tilting of the occupant supporting portion.

C..

The present invention provides a chair comprising a first portion for supporting an occupant and a second portion, the first portion being operatively connected to the second portion for tilting movement with respect to the second portion about a substantially horizontal axis and for displacement horizontally with respect to the second portion, an extensible means is provided for effecting the tilting movement Rand displacement of the first portion with respect to the second portion, one of the -3first and second portions having a roller rotatable about said horizontal axis, said roller being mounted on the other of the first and second portions for guided movement therealong thereby to provide said displacement between the first and second portions.

The pivotal movement of the first portion with respect to the roller provides the tilting movement, and rolling motion of the roller provides the displacement between the first and second portions.

The displacement of the first portion horizontally with respect to the second portion provides a shift in the centre of gravity of the first portion and any occupant supported therein in relation to the second portion.

The first portion may comprise a seat and a backrest, or a structure which carries the seat and backrest.

"Where the chair is a wheelchair or other form of mobile chair, the second portion may comprise a wheeled chassis.

S

15 Conveniently, the arrangement is such that the first portion is displaced horizontally with respect to the second portion during tilting movement of the first portion with respect to the second portion.

An extensible means is preferably provided whereby extension of the extensible means effects the tilting movement and displacement of the first portion with 20 respect to the second portion. The extensible means may comprise a manually operable mechanism or a power device such as a telescopic ram which may be electrically operable.

A guide means may be provided for guiding movement of the first portion with respect to the second portion. The guide means may comprise a link pivotally connected between the first and second portions for pivotal movement about respective axes parallel to said horizontal axis.

-4- Conveniently, the roller is mounted on the first portion and is in rolling engagement with the second portion. In such arrangement, the second portion preferably provides a track for the roller. The track may be provided by a frame element forming part of the second portion.

Conveniently, there are at least two of such rollers provided for rotation about the horizontal axis.

A restraining means may be provided for preventing separation between the or each roller and the portion with which it is in rolling engagement. The restraining means may also limit the extent of rolling movement of the or each roller.

The invention will be better understood by reference to the following description of several specific embodiments thereof as shown in the accompanying drawings in which: Fig. 1 is a schematic side view of a wheelchair according to a first embodiment, the wheelchair having an occupant supporting portion which is shown in a generally upright condition; Fig. 2 is a view similar to Fig. 1 with the exception that the occupant supporting portion is shown in a rearwardly inclined condition; Fig. 3 is an exploded view of a mobile base structure forming part of the wheelchair; Fig. 4 is a perspective view of the frame structure forming part of the mobile base structure, of Fig. 3, comprising the frame structure comprising an upper portion which is tiltable with respect to a lower portion and which is shown in a condition corresponding to the rearmost o tilted position of the wheelchair; Fig. 5 is a schematic side view of the frame structure in the condition shown in Fig. 4; Fig. 6 is a front view of the frame structure in the condition shown in Fig.

4; Fig. 7 is a plan view of the frame structure in a condition corresponding to that of Fig. 1 where an occupant of the chair would be supported in a upright position; Fig. 8 is a schematic side view of the frame structure in the condition shown in Fig. 7; Fig. 9 is a schematic front view of the frame structure in the condition shown in Fig. 7; Fig. 10 is a schematic view of a frame structure of a wheelchair according to a second embodiment; Fig. 11 is a schematic side view of the frame structure shown in Fig. 15 Fig. 12 is a schematic perspective view of a base structure of a wheelchair according to a third embodiment, in which the base structure is shown in a condition corresponding to the rearmost tilted position of the wheelchair; a.l Fig. 13 is a side view of the base structure in the condition shown in Fig.

12; Fig. 14 is a view similar to Fig. 12 with the exception that the base structure is shown in a condition where an occupant of the chair would be supported in an upright position; -6- Fig. 15 is a plan view of the base structure in the condition shown in Fig.

14; Fig. 16 is a front view of the base structure shown in the rearwardly tilted condition of Fig. 12; Fig. 17 is a front view of the base structure shown in the condition of Fig.

14; and Fig. 18 is an exploded view of the base structure of the third embodiment.

Referring to Figs. 1 and 8 of the drawings, there is shown a wheelchair according to the first embodiment which comprises an occupant supporting portion 10 supported on a mobile base structure 13. The occupant supporting portion 10 is detachable from the mobile base structure 13 to allow the wheelchair to be readily collapsed for transportation and storage.

The occupant supporting portion 10 comprises a seat 15, a backrest 17, and armrests 19.

15 The seat 15 includes a cushioned seat portion 21 mounted on a seat frame assembly 23.

The mobile base structure 13 includes a frame structure 25 carried on wheels 27.

The frame structure 25 includes a first frame portion 31 onto which the occupant S 20 supporting portion 10 is removably mounted, and a second frame portion 32.

*fee The first frame portion 31 is mounted onto the second frame portion 32 for tilting .•-.movement with respect thereto thereby to cause tilting of the occupant supporting portion 10 with respect to the mobile base structure 13. The occupant supporting portion can be tilted from a generally upright position (which is shown in Fig. 1) through a range of rearwardly inclined positions (one of which -7is illustrated in Fig. 2 of the drawings) to a rearmost inclined position (which is not shown).

The first frame portion 31 is mounted onto the second frame portion 32 for limited displacement with respect thereto along the fore-and-aft axis of the wheelchair as well as for the tilting movement which has been described. This allows the centre of gravity of the occupant supporting portion 10 and any occupant supported therein to shift upon tilting of the occupant supporting portion for the purposes of combating instabilities which might otherwise arise.

The first frame portion 31 is mounted onto the second frame portion 32 by way of a pair of rollers 33 mounted on the rearward end 34 thereof for rotation about a common substantially horizontal axis (designated by reference numeral 36).

The second frame portion 32 includes two longitudinal side frame sections 35 on which the rollers 33 are in rolling engagement for guided movement therealong.

A retaining means 37 in the form of a bracket is provided on each longitudinal frame section 35 to retain each respective roller 33 in engagement with the frame section and to limit the forward and rearward extent of rolling movement of :the roller along the frame section, as can be seen from the drawings.

With this arrangement, co-operation between the rollers 33 and the respective efl.

longitudinal frame sections 35 allows pivotal (tilting) movement of the first frame portion 31 with respect to the second frame portion 32 about the horizontal axis 36 defined by the rollers 33. Additionally, rolling motion of the rollers 33 on the longitudinal frame sections 35 allow limited displacement of the first frame portion 31 with respect to the second frame portion 32 in a direction which is transverse to the horizontal axis 36 and thus in the fore-and-aft direction of the wheelchair.

A control means 41 is provided for effecting the tilting movement and the displacement of the first portion 31 with respect to the second portion 32. The control means 41 comprises an extensible means in the form of a pair of -8electrically operable telescopic rams 43 connected for operation between the first portion 31 and the second portion 32. The two rams 43 extend upwardly and forwardly from the second portion 32 to the first portion 31, as best seen in Figs. 4, 5 and 8 of the drawings. Each ram 43 is mounted at its lower end onto a transverse element 45 which is pivotally mounted by way of brackets 47 onto the second frame portion 32. The upper end of each ram 43 is pivotally mounted at 49 onto the forward end 50 of the first frame portion 31.

The inclination at which the rams 43 are mounted between the first frame portion 31 and the second frame portion 32 is such that extension of the rams to effect upward tilting of the first frame portion 31 about the horizontal axis 36 at the rollers 33 also causes the first frame portion 31 to be displaced forwardly. The forward displacement of the first frame portion 31 with respect to the second frame portion 32 is accommodated by rolling movement of the rollers 33 on the tracks provided by the longitudinal frame sections 35. The extent of rolling 15 movement is limited by the retaining means 37. Retraction of the rams 43 *00.*O causes the first frame portion 31 to tilt downwardly and be displaced rearwardly to assume a lowermost position which is best seen in Fig. 8 of the drawings.

e This lowermost position corresponds to the upright condition of the occupant supporting portion 10 of the wheelchair as shown in Fig. 1 of the drawings.

eeoc 20 Because of the occupant supporting portion 10 of the wheelchair is mounted on the first frame portion 31 of the frame structure 25, it is tilted in unison with tilting movement of the first frame portion 31 with respect to the second frame portion 32.

With this arrangement, the occupant supporting portion 10 of the wheelchair shifts forwardly and rearwardly with respect to the mobile base structure 13 with tilting of the occupant supporting portion. More particularly,' the occupant supporting portion 10 shifts forwardly with respect to the mobile base structure 13 as the portion 10 is tilted rearwardly. Similarly, the occupant receiving portion shifts rearwardly as it is tilted in a forward direction towards the upright -9position shown in Fig. 1 of the drawings. As previously mentioned, the shifting movement of the occupant supporting portion 10 with respect to the base structure 13 provides some compensation for the shift in the centre of gravity of the occupant supporting portion and any occupant supported therein during tilting thereby to enhance the stability of the wheelchair.

In the first embodiment, movement between the first frame portion 31 and the second frame portion 32 was effected by a control means 41 in the form of electrically operable rams 43. In this second embodiment, which is shown in Figs. 10 and 11, the power devices are replaced by manually operable struts 61.

Each strut 61 comprises two telescopic sections 62, 63 which can be fixed relative to each other by a locking mechanism 65. With this arrangement, the telescopic sections 62, 63 of the struts 61 are adjusted in length as the occupant supporting portion 10 is tilted into the desired position with respect to the mobile base structure 13. The locking mechanism 65 are then operated to lock the 15 telescopic sections 62, 63 of the struts 61 together and thereby lock the occupant supporting portion 10 at the desired position. When it is necessary to change the inclination of the occupant supporting portion 10, the locking mechanism 61 on the struts are released thereby allowing the occupant supporting portion to be tilted into the new position.

20 Referring now to Figs. 12 to 18, the wheelchair according to the third embodiment has a base structure which is somewhat similar to the base structure 25 of the wheelchair of the first embodiment and so like reference numerals are used to identify like parts.

In this embodiment, the control means 41 comprises a single telescopic ram 71 which is electrically operable. The telescopic ram 71 is pivotally mounted at its lower end onto a frame element 73 which is part of the second frame portion 32.

A mounting bracket 75 is provided for this purpose on the frame element. The ram 71 is pivotally mounted at its upper end onto the first frame portion 31, and a mounting bracket 77 is provided for this purpose.

A guide means 81 is provided between the first frame portion 31 and the second frame portion 32 at the forward end thereof for guiding movement of the first portion relative to the second portion upon operation of the telescopic ram 71.

The guide means 81 provides lateral stability to the first frame portion 31 during movement thereof. This may be necessary owing to the fact that there is only one ram 71.

The guide means 81 comprises a pair of pivotal links 83. Each link 83 is rigidly connected at its lower end onto a shaft 84 rotatably mounted between brackets on the second frame portion 32 for rotation about an axis parallel to the axis 36 defined by the rollers 33. Each link 83 is also pivotally connected.at its upper end onto a respective bracket 87 on the first frame portion 31 for pivotal movement about a pivot axis parallel to the axis 36 defined by the rollers 33.

The pivotal links 83 move in response to movement between the first and second frame portions 31, 32 and act to guide such movement and so provide 15 stability to the first frame portion.

00:i From the foregoing, it is evident that the present invention provides a simple yet highly effective system which provides some compensation for a shift in the centre of gravity of the occupant supporting portion and any occupant supported therein during tilting of the wheelchair.

S. 20 It should be appreciated that the scope of the invention is not limited to the scope of the various embodiments which have been described. In particular, it should be understood that the invention may have application to chairs other than wheelchairs.

Claims

1. A chair comprisirg a first portion for supporting an occupant and a second portion, the first portion being operatively connected to the second portion for tilting movement with respect to the second portion about a substantially horizontal axis and for displacement horizontally with respect to the second portion, an extensible means for effecting the tilting movement and displacement of the first portion with respect to the second portion, one of the first and second portions having a roller rotatable about said horizontal axis, said roller being mounted on the other Of the first and second portions for guided movement therealong thereby to provide said displacement ~9 between the first and second portions. Si'•

2. A chair according to claim 1 wherein the first portion comprises a seat and a S. backrest, or a structure which carries the seat and backrest.

3. A chair according to claim 1 or 2 wherein the second portion comprises a wheeled chassis. o 0

4. A chair according to any one of the preceding claims wherein the first portion is displaced horizontally with respect to the second portion during tilting movement of the first portion with respect to the second portion.

A chair according to claim 1 whereby extension of the extensible means effects the tilting movement and displacement of the first section with respect to second portion.

6. A chair according to claim 1 wherein the extensible means comprises a manually operable mechanism.

7. A chair according to claim 1 wherein the extensible means comprises a power device. -12-

8. A chair according to claim 7 wherein the power devices comprises a telescopic ram.

9. A chair according to claim 8 wherein the telescopic ram is electrically operable.

10. A chair according to any one of the preceding claims wherein the roller is mounted on the first portion and is in rolling engagement with the second portion.

11. A chair according to claim 10 wherein the second portion provides a track for the roller.

12. A chair according to any one of the preceding claims wherein there are two of said rollers provided for rotation about the horizontal axis. B"

13. A chair according to any one of the preceding claims wherein a restraining o means prevents separation between the or each roller and the portion with which it is in rolling engagement. 15

14. A chair according to claim 13 wherein the restraining means limits the extent of rolling movement of the or each roller.

15. A chair according to any one of the preceding claims wherein movement of S°the first portion with respect to the second portion is guided by a guide means.

16. A chair according to claim 15 wherein the guide means comprises a link pivotally connected between the first and second portions for pivotal movement about respective axes parallel to said horizontal axis. -13-

17. A chair substantially as herein described with reference to the accompanying drawings. DATED this seventeenth day of May 2000 LENDAL PTY LTD Applicant WRAY ASSOCIATES Perth, Western Australia Patent Attorneys for Applicant