WO2023081957A1

WO2023081957A1 - Wheelchair frame assembly

Info

Publication number: WO2023081957A1
Application number: PCT/AU2022/051253
Authority: WO
Inventors: Paul Francis Salfinger
Original assignee: Kylix Pty Ltd
Priority date: 2021-11-12
Filing date: 2022-10-18
Publication date: 2023-05-19
Also published as: AU2022387142A1

Abstract

A frame assembly 11 for a wheelchair comprising a left side frame component 13 and a right side frame component 15 spaced apart as a pair. Each side frame component 13, 15 has an upper longitudinal member 21, 27, 21' 27' and a lower longitudinal member 23, 29, 23', 29', rigidly supported relative to each other, and linked by a scissor mechanism 37 having cross-linked arms 61, 63 spaced from each other about a scissor axis 67. The cross linked arms 61, 63 have lower arm portions 69, 69' connecting via lower pivot points 35, 35' to the lower longitudinal members, and upper arm portions 61, 63 each terminating in a longitudinal seat support member 75', 75 respectively, extending substantially parallel with the upper longitudinal members. Each upper arm portion 75', 75 is pivotally connected by an articulating linkage 77', 77 from a pivotal position 81' 81 along the upper arm portions located between the scissor axis 67 and the longitudinal seat support member 75', 75, to a pivotal connection 81' 81 with the upper longitudinal members. The frame assembly 11 is movable between an extended position (fig 1) in which a wheelchair would be used and a folded position (fig 3) in which the wheelchair would be stowed. In the extended position, the upper arm portions and said longitudinal seat support members locate substantially in a common plane.

Description

Wheelchair Frame Assembly

Field of the Invention

[0001] This invention relates to wheelchairs, and in particular to a collapsible frame assembly for a wheelchair.

Background

[0002] The following discussion of the background art is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge as at the priority date of the application.

[0003] Wheelchairs are often used by the infirm or those convalescing following injury or surgery. Typical wheelchairs used in a hospital setting comprise a fixed frame supporting a seat portion with a back rest, having two large wheels either side of the seat portion disposed rearward, and a pair of castors located forward, usually either side of one or a pair of foot rests.

[0004] A requirement for greater mobility and the ability to easily transport a wheelchair with its owner/user has seen the development of collapsible wheelchairs. These typically have a pair of side frames, usually disposed in parallel, supported from each other by a scissor mechanism allowing movement of the side frames relative to each other between a deployed position in which the side frames are spaced away from each other, and a stowed position in which the side frames are located toward and closer to each other.

[0005] The inventor has developed a new collapsible wheelchair frame that possesses a number of advantages over hitherto described arrangements.

[0006] Throughout the specification unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Summary of Invention

[0007] In accordance with one aspect of the present invention, there is provided a frame assembly for a wheelchair comprising a left side frame component and a right side frame component spaced apart as a pair, each of said side frame components having an upper longitudinal member and a lower longitudinal member rigidly supported relative to each other, said pair of spaced apart side frame components being linked by a scissor mechanism having cross-linked arms spaced from each other about a scissor axis, said cross linked arms having lower arm portions connecting via lower pivot points to said lower longitudinal members, and upper arm portions each terminating in a longitudinal seat support member extending substantially parallel with said upper longitudinal members, each of said upper arm portions being pivotally connected by an articulating linkage from a pivotal position on said upper arm portions located between said scissor axis and said longitudinal seat support member, to a pivotal connection with said upper longitudinal members; where said frame assembly is movable between an extended position in which a wheelchair would be used and a folded position in which the wheelchair would be stowed, where in the extended position, said upper arm portions and said longitudinal seat support members locate substantially in a common plane.

[0008] Preferably, the geometry of said scissor mechanism is such that in the extended position, for each of said cross linked arms, the scissor axis locates below a line extending from the lower pivot points axis and the longitudinal seat support members axial extent, and said pivotal position axis on each of said cross linked arms is located above said line.

[0009] Preferably backrest support arms extend upward from the rear of said upper longitudinal members.

[0010] The effect of the geometry of the scissor mechanism, as described, is to force the upper longitudinal members apart further than the lower longitudinal members, as the frame assembly is moved from the extended position. This in conjunction with tension supplied by a backrest extending between back rest support arms creates an over-center effect as the frame assembly is extended, causing the wheelchair to urge into the extended position.

[0011] Preferably said backrest support arms are pivotally mounted to said upper longitudinal members about a transverse axis, and include a mechanism to lock the backrest arms at an angle as desired by a user. The mechanism may be a bolt extending through an arcuate aperture in a mount for each backrest support arm, spaced from said transverse axis, which may be tightened when the backrest support arms are in the desired position.

[0012] The arrangement of the backrest support arms being fixed to the upper longitudinal members and the longitudinal seat support members supporting the seat, allows the wheelchair to be folded, regardless of the backrest support arm positions, as the backrest support arms lie outside of the locus of movement of the seat support members.

[0013] Preferably said lower longitudinal members are of tubular configuration, preferably circular tubular, and said lower pivot points are in coaxial alignment with the axial extent of said lower longitudinal members.

[0014] Preferably each said articulating linkage is of a curved configuration, to accommodate a said seat support member when said frame assembly is in the extended position.

[0015] Preferably each said upper longitudinal member is provided with at least one support finger extending inwardly, on which an adjacent seat support member rests when said frame assembly is in the extended position. It should be sufficient that each upper longitudinal member is provided with two such support fingers, one in a forward position and the other in a rearward position relative to the seat position.

Brief Description of Drawings

[0016] In order to provide a better understanding, a preferred embodiment of the present invention, being a foldable/collapsible frame assembly for a wheelchair, will be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of the collapsible frame assembly for a wheelchair according to the embodiment;

Figure 2 is an exploded perspective view of the collapsible frame assembly for a wheelchair;

Figure 3 is a front perspective view of the collapsible frame assembly for a wheelchair shown in a fully folded/collapsed condition;

Figure 4 is a front perspective view of the collapsible frame assembly for a wheelchair shown in a position between the fully folded/collapsed condition and an extended position;

Figure 5 is a rear plan view of the collapsible frame assembly for a wheelchair as shown in figure 3;

Figure 6 is a rear plan view of the collapsible frame assembly for a wheelchair as shown in figure 4;

Figure 7 is a rear plan view of the collapsible frame assembly for a wheelchair shown in the extended position; Figure 8 is a part side view of the inside of the right side frame component and part of a cross-linked arm and part of an articulating linkage of the scissor mechanism; and

Figure 9 is a top plan view of the collapsible frame assembly for a wheelchair shown in the extended position.

Description of the Embodiment

[0017] The embodiment is a foldable/collapsible frame assembly 11 for a wheelchair, shown generally in figures 1, 3 to 7, and 9. The frame 11 has a left side frame component 13 and a right side frame component 15 which are spaced apart as a pair, generally disposed in parallel with each other at least in a folded/co I lapsed condition as shown in figures 3 and 5.

[0018] Each of the side frame components 13 and 15 has a front u-shaped frame member 17 and 17' and rear u-shaped frame member 19 and 19' respectively. The front u-shaped frame members 17 and 17' comprise an upper leg 21 and 21' and a lower leg 23 and 23' respectively, joined by respective webs 25 and 25'. The rear u-shaped frame members 19 and 19' comprise an upper leg 27 and 27' and a lower leg 29 and 29' respectively, joined by respective webs 31 and 31'. The upper legs 21 and 27 are disposed along a common axis and telescopingly receive a tubular hinge pin 33. The upper legs 21' and 27' are disposed along a common axis and telescopingly receive a tubular hinge pin 33'. Similarly, the lower legs 23 and 29 are disposed along a common axis and telescopingly receive a tubular hinge pin 35. The lower legs 23' and 29' are disposed along a common axis and telescopingly receive a tubular hinge pin 35'. The four tubular hinge pins 33, 33', 35, and 35' provide pivoting axes for a scissor mechanism 37 as will be described.

[0019] The webs 25 and 25' each have a pair of outward and upwardly disposed mounting pins 39, each pair being provided to support a footrest (not shown) which may be rotated about a vertical axis. At the junction of the web 25 and the lower leg 23, and also at the junction of the web 25' and the lower leg 23', is provided a mounting point in the form of two mounting apertures, each provided to fit a mounting socket 41 and 41' for receiving a castor 43 and 43' (shown in dashed outline). The front part of each mounting socket 41 and 41' has an elongated arcuate aperture with its axis through an aperture at the rear part of each mounting socket, allowing the angle (in a front to rear vertical plane) of the mounting sockets 41 and 41' to be adjusted.

[0020] The webs 31 and 31' are each provided as a pair of spaced vertical members 45 and 45' having equidistant spaced apertures for receiving bolts to mount a rear wheel axle mount 47, which can be fitted either way around to dispose a rear wheel axle bush 48 for a rear wheel axle 49 in a forward position as shown (a notional rear wheel 51 is shown in dashed outline as it would be located in the forward position), or the other way around to dispose the rear wheel axle 49 in a rearward position. The spaced apertures allow the fitment height of the rear wheel axle mount 47 to be adjusted, which together with the ability to set the rear wheel axle 49 forward or rearward, depending on which way around the rear wheel axle mount 47 is fitted to the spaced vertical members 45 and 45', and which large aperture 52 the rear wheel axle bush 48 is fitted, allows for a number of wheel base and seat inclination combinations to be set. Mounting the rear wheel axle forward to provide a short wheel base can allow for an extremely highly balanced wheelchair frame for sport use, which would have a deep seat fall and a 90 degree backrest angle. A longer wheel base can be set for greater stability such as when partial backrest recline is set, or for amputee use. The angle (in a front to rear vertical plane) of the mounting sockets 41 and 41' for the castors is adjusted to suit the position that the rear wheel axle mount 47 is fitted .

[0021] At the junction of the web 31 and upper legs 27, and also at the junction of the web 31' and the upper legs 27, is provided a backrest post mount 53 and 53', each provided to mount a backrest post 54 and 54'. The backrest post mount 53 and 53', each have an upper aperture 55 and a lower arcuate aperture 57, the lower arcuate aperture 57 allowing the angle of the backrest post 55 and 55' to be adjusted and set in a desired forward or rearward position in a forward and rearward vertical plane, between forward and rearward extremes as shown in figure 8.

[0022] The upper legs 21 and 27 disposed along the common axis telescopingly with the tubular hinge pin 33, and the upper legs 21' and 27' disposed along the common axis telescopingly with the tubular hinge pin 33', form upper longitudinal members of the spaced apert side frame components 13 and 15. Similarly, the lower legs 23 and 29 disposed along the common axis telescopingly with the tubular hinge pin 35, and the lower legs 23' and 29' disposed along the common axis telescopingly with the tubular hinge pin 35', form lower longitudinal members of the spaced apart side frame components 13 and 15. The upper longitudinal member and lower longitudinal member of each side frame component 13 and 15 are rigidly supported relative to each other, by their respective webs 25, 31, and 25', 31'.

[0023] The left side frame component 13 and right side frame component 15 are maintained spaced apart in linkage by the scissor mechanism 37 having cross-linked arms 61 and 63 spaced from each other by a spacer 65 (see figure 9) about a scissor axis 67. The cross-linked arms 61 and 63 each have lower arm portions 69 and 69' connecting via lower pivot points formed by lower tubular members 71 and 71' which are received telescopingly, one on each tubular hinge pin 35 and 35', between lower legs 23 and 29 and lower legs 23' and 29' respectively. As the lower tubular members 71 and 71' rotate releative to their respective tubular hinge pins 35 and 35', the fitting is lubricated with grease on assembly. The lower legs 23 and 29 and lower legs 23' and 29' are riveted to their respective tubular hinge pins 35 and 35', at the appropriate time, once the entire frame 11 has been assembled. For reasons of uniformity and exchangeability of components, the riveting should be through jig drilled apertures formed in the parts prior to assembly, rather than being performed on an ad-hoc basis.

[0024] The cross linked arms 61 and 63 each have upper arm portions 73 each terminating in a tubular longitudinal seat support member 75 and 75' which both extends substantially parallel with co-locatable upper longitudinal members formed by the upper legs 21' and 27' and upper legs 21' and 27' respectively. Each of said upper arm portions 73 is pivotally connected by an articulating linkage in the form of a travel arm 77 and 77' from a pivotal position 79 and 79' on the associated upper arm portions 73 located between the scissor axis 67 and the longitudinal seat support members 75 and 75', the travel arms 77 and 77' extending below the upper arm portions 73.

[0025] The travel arms 77 and 77' each extend to a pivotal connection formed by upper tubular members 81 and 81' which are received telescopingly, one on each tubular hinge pin 33 and 33', between upper legs 21 and 27 and upper legs 21' and 27' respectively. As the upper tubular members 81 and 81' also rotate relative to their respective tubular hinge pins 33 and 33', the fitting is lubricated with grease on assembly. The upper legs 21 and 27 and upper legs 21' and 27' are riveted to their respective tubular hinge pins 33 and 33', at the appropriate time, once the entire frame 11 has been assembled.

[0026] The frame assembly 11 is movable between an extended position shown in figures 1, 7, and 9, in which a wheelchair would be used and a folded position shown in figures 3 and 5 in which the wheelchair would be stowed. In the extended position, as can be seen in figures 1 and 7, the upper arm portions formed by the upper legs 21, 27 and upper tubular member 81, and by the upper legs 21', 27' and upper tubular member 81', and said longitudinal seat support members 75 and 75' locate substantially in a common plane.

[0027] The geometry of the scissor mechanism 37 is such that in the extended position, for each of the cross linked arms 61 and 63, the scissor axis 67 locates below a line extending from the lower pivot points axis being the axial extent of the tubular hinge pins 35 and 35' and the longitudinal seat support members 75' and 75, respectively, axial extent, and the pivotal position axis 79 and 79' on each of said cross linked arms is located above this line. [0028] The effect of the geometry of the scissor mechanism 37, as described, is to force the upper longitudinal members (axes of the tubular hinge pins 33 and 33') apart further than the lower longitudinal members (axes of the tubular hinge pins 35 and 35'), as the frame assembly is moved from the extended position. This in conjunction with tension supplied by a backrest 83 extending between back rest support arms 54 and 54' creates an over-center effect as the frame assembly is extended, causing the wheelchair frame 11 to urge into the extended position.

[0029] The longitudinal seat support members 75 and 75' support a seat (shown in dashed outline 85 in figure 1) between them in the extended position. Each articulating linkage 77 and 77' is bifurcated as in the form of a clevis to attach either side of cross linked arm 61 or 63 about the pivotal axis 79 and 79', and is of a curved configuration, to accommodate a longitudinal seat support member 75 or 75' when said frame assembly is in the extended position.

[0030] The upper legs 21, 27, and the upper legs 21', 27' forming the two upper longitudinal members are each provided with a support finger 87 extending inwardly to a position lying under a proximal longitudinal seat support member 75, 75', to provide support for a proximal longitudinal seat support member 75, 75' to rest thereon when the frame assembly 11 is in the extended position. As the wheelchair frame external parts would typically be powder-coated aluminium, the support fingers 87 would be provided with self-adhesive attached felt pads to prevent the powder-coating from being fractured, which might lead to corrosion.

[0031] The arrangement of the backrest support arms 54 and 54' being fixed to the upper longitudinal members and the longitudinal seat support members 75, 75' supporting the seat 85, allows the wheelchair to be folded, regardless of the backrest support arm positions, as the backrest support arms lie outside of the locus of movement of the seat support members. While not shown, armrests can be attached to the tops of the frame components 13 and 15, conveniently by being clamped about the upper legs 21 and 21' in a forward position of the armrests, and at the rearward position of the armrests, bolted to apertures in the backrest post mounts 53 and 53'.

[0032] The arrangement of the longitudinal seat support members nesting within the upper longitudinal members provides superior rigidity to the wheelchair frame in the extended position, compared with conventional arrangements where the longitudinal seat support members locate on top of the equivalent side frames, and may be flexed back and forth relative thereto. In addition, the geometry of the scissor mechanism allows for a more compact folded width compared with many conventional arrangements. [0033] The configuration of the frame assembly 11 allows the wheelchair to be folded (collapsed) and unfolded (opened out) without being impeded by the side frames and any arm rests attached thereto, or the position of the backrest support arms 54 and 54'. This allows the folding scissor mechanism 37 to locate internally with respect to the side frames 13 and 15, allowing the wheelchair to be set up in a number of different configurations, including the backrest adjusted forward or rearward of centre, and the wheelchair to be collapsed and opened out without needing to adjust or remove/refit the backrest support arms 54 and 54'.

[0034] It should be appreciated that the scope of the invention is not limited to the particular embodiment described herein, and a person skilled in the art will understand that changes may be made without departing from the spirit and scope of the invention.

Claims

9 Claims

1. A frame assembly for a wheelchair comprising a left side frame component and a right side frame component spaced apart as a pair, each of said side frame components having an upper longitudinal member and a lower longitudinal member rigidly supported relative to each other, said pair of spaced apart side frame components being linked by a scissor mechanism having cross-linked arms spaced from each other about a scissor axis, said cross linked arms having lower arm portions connecting via lower pivot points to said lower longitudinal members, and upper arm portions each terminating in a longitudinal seat support member extending substantially parallel with said upper longitudinal members, each of said upper arm portions being pivotally connected by an articulating linkage from a pivotal position on said upper arm portions located between said scissor axis and said longitudinal seat support member, to a pivotal connection with said upper longitudinal members; where said frame assembly is movable between an extended position in which a wheelchair would be used and a folded position in which the wheelchair would be stowed, where in the extended position, said upper arm portions and said longitudinal seat support members locate substantially in a common plane.

2. A frame assembly for a wheelchair as claimed in claim 1, wherein the geometry of said scissor mechanism is such that in the extended position, for each of said cross linked arms, the scissor axis locates below a line extending from the lower pivot points axis and the longitudinal seat support members axial extent, and said pivotal position axis on each of said cross linked arms is located above said line.

3. A frame assembly for a wheelchair as claimed in claim 1 or 2, wherein a backrest support arm extends upward from the rear of each said upper longitudinal member.

4. A frame assembly for a wheelchair as claimed in claim 3, wherein said backrest support arms are pivotally mounted to said upper longitudinal members about a transverse axis, and include a mechanism to lock the backrest arms at an angle as desired by a user.

5. A frame assembly for a wheelchair as claimed in claim 4, wherein the mechanism comprises a bolt extending through an arcuate aperture in a mount for each backrest support arm, spaced from said transverse axis, which may be tightened when the backrest support arms are in the desired position.

6. A frame assembly for a wheelchair as claimed in any one of the preceding claims, wherein said lower longitudinal members are of tubular configuration, and said lower pivot points are in coaxial alignment with the axial extent of said lower longitudinal members.

7. A frame assembly for a wheelchair as claimed in claim 6, wherein the tubular configuration is a circular tubular configuration.

8. A frame assembly for a wheelchair as claimed in any one of the preceding claims, wherein each said articulating linkage is of a curved configuration, to accommodate a said seat support member when said frame assembly is in the extended position.

9. A frame assembly for a wheelchair as claimed in any one of the preceding claims, wherein each said upper longitudinal member is provided with at least one support finger extending inwardly, on which an adjacent seat support member rests when said frame assembly is in the extended position.

10. A frame assembly for a wheelchair as claimed in claim 9, wherein each upper longitudinal member is provided with two support fingers, one in a forward position and the other in a rearward position relative to the seat position.