WO2023086030A2

WO2023086030A2 - Apparatus with pivoted wheel mechanism

Info

Publication number: WO2023086030A2
Application number: PCT/SG2022/050821
Authority: WO
Inventors: Chee Meng CHEW; Rayner Renyi TAN
Original assignee: National University Of Singapore
Priority date: 2021-11-11
Filing date: 2022-11-11
Publication date: 2023-05-19
Also published as: TW202410874A; WO2023086030A3

Abstract

The present invention describes a wheeled apparatus (100) for carrying a load or a person. A travel wheel (150, 150a) or travel wheels (150, 150a) of the wheeled apparatus (100) is/are suspended by each associated pivot link member (105, 105a-105e) to a chassis (102) of the wheeled apparatus; the pivot link member is free to pivot when the wheeled apparatus travels over an uneven terrain; as a result, the wheeled apparatus experiences reduced impact forces and this invention thus provides a user a smooth ride over an uneven terrain.

Description

Apparatus with Pivoted Wheel Mechanism

Related Application

[001] The present invention claims priority to Singapore patent application no. 10202112540T filed on 11 November 2021, the disclosure of which is incorporated in its entirety.

Field of Invention

[002] The present invention relates to a pivoted wheeled apparatus for providing smoother travel over a step or an uneven terrain. The pivoted wheeled apparatus is useful for carrying a load or a person, such as a wheelchair, trolley, cart, stroller, and so on. The pivoted wheeled apparatus may be manually driven or power-driven.

Background

[003] Wheeled apparatuses, including wheelchairs, trolleys, carts, wheelbarrows, strollers and so on, are used to carry people or loads and require lower input efforts, both manually or being power-driven. When such a wheeled apparatus travels over an uneven terrain, including a kerb or a step, the wheeled apparatus experiences impact forces; when such a wheeled apparatus is used to transport a person, comfort necessitates reducing such impact forces. Not all of such wheeled apparatus can be easily equipped or adapted to absorb these impact forces.

[004] It can thus be seen that there exists a need to provide a mechanism that is easily fitted to a wheeled apparatus to provide smooth travel over an uneven terrain, both as a new apparatus or a retro-fitted apparatus. Desirably, such a mechanism is simple and easy to maintain.

Summary

[005] The following presents a simplified summary to provide a basic understanding of the present invention. This summary is not an extensive overview of the present invention, and is not intended to identify key features of the invention. Rather, it is to present some of the inventive concepts of this invention in a generalised form as a prelude to the detailed description that is to follow.

[006] The present invention seeks to provide a pivot mechanism to a wheeled apparatus to provide smoother travel over an uneven terrain. Desirably, the pivoted wheeled apparatus may be a new or retrofitted contraption.

[007] In one embodiment, the present invention provides a wheeled apparatus comprising: a travel wheel; a chassis axle of the wheeled apparatus; a pivot link member, which is elongated and having two substantially parallel, offset axes located on two opposite ends, with a first axis being operable to journal with an axle of the travel wheel and a second axis being operable to journal with the chassis axle; wherein, when the wheeled apparatus travels over an uneven terrain, the pivot link member pivots about the two substantially parallel axes, thereby damping impact forces transmitted onto the wheeled apparatus, and providing a travel that is smoother and with lower mechanical efforts.

[008] Preferably, the first or the second axis is configured with two or more substantially parallel axes at the nexus end of the pivot link member, so as to provide height adjustment for the wheeled apparatus.

[009] Preferably, the pivot link member is configured with a uniform thickness and a uniform width. Alternatively, the pivot link member is configured with the opposite ends being non- uniform in thickness. In another embodiment, a lower end of the pivot link member has a thickness more than a thickness of an upper end, such that centre lines of the upper end and the lower end are offset. The pivot link member may comprise a hollow portion or aperture located between the substantially parallel axes, so as to reduce a weight of the pivot link member.

[0010] Preferably, an interlock mechanism is provided to fix or limit the travel of an upper end of the pivot link member with respect to the chassis of the wheeled apparatus. The interlock mechanism may be a clip-on device or a push-pull device located coaxially with the axle of the travel wheel.

[0011] Preferably, a clamp member is provided to fit onto the chassis of the wheeled apparatus to support the chassis axle. [0012] In another embodiment, the present invention also provides a kit of parts for retrofitting or adapting the wheeled apparatus of the present invention.

[0013] In yet another embodiment, the present invention provides a method for improving impact dampening or smoothening of a wheeled apparatus when travelling on an uneven terrain, the method comprising: connecting a travel wheel to an axle of the wheeled apparatus with a pivot link member, wherein two substantially parallel, offset axes on opposite ends of the pivot link member are free to pivot and thus provide improved impact dampening or a smoother locus of motion.

Brief Description of the Drawings

[0014] This invention will be described by way of non-limiting embodiments of the present invention, with reference to the accompanying drawings, in which:

[0015] FIG. 1 illustrates a wheeled apparatus, exemplified by a wheelchair, fitted with a pivot link member located between a travel wheel and a chassis of the wheelchair according to an embodiment of the present invention; FIG. 2 illustrates a closed-up view of the pivot link member;

[0016] FIGs. 3 and 4 illustrate simple schematic representations of the wheelchair shown above;

[0017] FIGs. 5 and 7 illustrate loci of motions of a conventional wheelchair, whilst FIGs. 6 and 8 illustrate respective comparative loci of motions of the wheelchair of the present invention;

[0018] FIGs. 9-16 illustrate various embodiments of the pivot link member shown above;

[0019] FIGs. 17-21 illustrate a wheelchair of the present invention being pulled over a step;

[0020] FIGs. 22-25 illustrate a wheelchair of the present invention being propelled over a step; [0021] FIGs. 26-27 illustrate lower parts of the wheelchair chassis being fitted with axles that are operable to journal with a lower pivot axis of the above pivot link member;

[0022] FIG. 28 illustrates a wheelchair fitted with a pivot link member according to another embodiment;

[0023] FIG. 29 illustrates an interlock mechanism on the pivot link member according to another embodiment of the present invention;

[0024] FIG. 30 illustrates lifting of a wheelchair of the present invention without an interlock mechanism, whilst FIG. 31 illustrates lifting of a wheelchair fitted with an interlock mechanism; and

[0025] FIG. 32 illustrates an interlock mechanism on the pivot link member according to yet another embodiment of the present invention.

Detailed Description

[0026] One or more specific and alternative embodiments of the present invention will now be described with reference to the attached drawings. It shall be apparent to one skilled in the art, however, that this invention may be practised without such specific details. Some of the details may not be described at length so as not to obscure the invention. For ease of reference, common reference numerals or series of numerals will be used throughout the figures when referring to the same or similar features common to the figures.

[0027] The present invention describes and illustrates a wheeled apparatus 100, as embodied by a wheelchair 100 as an example, according to the present invention. Other types of wheeled apparatuses 100 that can be used with this invention include: trolleys, carts, wheelbarrows, strollers, and similar wheeled devices.

[0028] FIG. 1 shows a picture of the wheelchair 100 fitted with a pivot link member 105, which connects a lower part of a chassis 102 of the wheelchair or wheeled apparatus 100 to an axle 152 of a travel wheel 150 according to one embodiment of the present invention. FIG. 2 shows a closer view of the pivot link member 105 assembly. The link member 105 is an elongate structure and has two substantially parallel pivot axes 110,112 being located near two opposite ends; when the wheeled apparatus 100 travels over an uneven terrain, the pivot link member 105 can pivot freely about these axes 110,112, thereby providing a smoother ride when compared to a conventional wheelchair. FIGs. 3 and 4 show schematic illustrations of the wheelchair 100. As seen in FIG. 3, the upper pivot axes 110 are journaled to the respective axles 152 of the travel wheels 150, whilst the lower pivot axes 112 are journaled to respective chassis axles 104 of the wheelchair 100. When the wheelchair 100 experiences impact forces as it moves over an uneven terrain, the pivot link member 105 is free to pivot about both axes 110,112, thereby allowing the link member 105 to swing about these axes and to give the chassis 102 of the wheeled apparatus 100 a resulting smoother locus of motion.

[0029] FIGs. 5 and 7 show loci of motions L1,L2 of a conventional wheeled apparatus, which loci trace abrupt motions as the wheels 15 traverse over a step 10 or a series of humps 11 that represent an uneven terrain. FIGs. 6 and 8 show loci of motions L3,L4 of the wheeled apparatus 100 of the present invention, with the loci L3,L4 showing comparatively smooth transitions as the travel wheels 150 traverse over the uneven terrain.

[0030] The pivot link member 105 can be configured in various manners. In one embodiment, the pivot link member 105 is symmetrical along its length, and the pivot axes 110,112 are located at two opposite ends, as shown in FIG. 9. The pivot axes 110,112 are substantially parallel to each other. Also as seen in FIG. 9, the pivot link member 105 has a uniform thickness T in a transverse direction, whilst FIG. 11 shows a side view with the pivot link member 105 having a uniform width W.

[0031 ] FIG. 10 shows a pivot link member 105a according to another embodiment. As shown in FIG. 10, a lower end of the pivot link member 105a has a thickness T2 that is more than a thickness T1 at the upper end; in other words, the opposite ends of the pivot link member 105a are offset in the transverse direction. By offsetting the lower end of the pivot link member 105a, a gap spacing between the lower end of the pivot link member 105a and the travel wheel 150 becomes bigger; this is to minimise a human hand, for eg., from being caught accidentally in a small gap spacing between the pivot link member and travel wheel 150. FIG. 11 shows the width W of the pivot link member 105a is uniform, but it is not so limited. [0032] The pivot link member 105,105a can be made from various materials or formed by various fabrication processes. For eg., the pivot link member 105,105a can be made of steel, aluminium, engineering plastic, reinforced composite, and so on. The pivot link member 105,105a can also be machined out from a block, or cast or formed with a mould. It is possible that a part of the pivot link member 105,105a between the pivot axes 110,112 is hollowed out 120 (for eg., by machining or casting) to lighten the pivot link member; in one embodiment, a pivot link member 105b with a hollowed out portion 120 is shown in FIG. 12; as seen in FIGs. 12-13, a shank material 121 and surrounding webs 122 around the hollow portion 120 provide strength and rigidity to the pivot link member 105b.

[0033] In FIGs. 12-13, the hollow portion 120 on the pivot link member 105b is located on an outer face of the pivot linked member. In another embodiment, a hollow portion 120a on a pivot link member 105c, as shown in FIG. 14, is located on an inner face and the shank material 121a is located on the right hand side. In yet another embodiment, hollow portions 120b, 120c are located on both the inner and outer faces, leaving a shank 121b and webs 122b materials around the hollow portions 120b, 120c, as seen in FIG. 15, to provide strength and rigidity to a pivot link member 105d. FIG. 16 shows the width of the pivot link members 105c, 105d is uniform, but it is not so limited.

[0034] Whilst the above describes providing the hollow portion 120,120a-120c on the pivot link member, it is possible to provide more than one hollow portions along the length of the pivot link member. It is also equally possible that the hollow portion(s) is/are aperture(s) formed through the thickness of the pivot link member, without affecting the strength, rigidity or functionality of the pivot link member.

[0035] In FIGs. 14-16, the pivot link members 105c, 105d are provided with 3 lower pivot axis 112, 112a, 112b according to another embodiment; these 3 pivot axes provide alternative positions for journaling with the chassis axle 104, so as to allow a height of the wheeled apparatus 100 to be adjustable; this height adjustment feature is helpful when the wheeled apparatus 100 is used by an adult or a child, or as a need arises. It is also possible that the above pivot link members 105, 105a, 105b are also provided with more than one upper pivot axis 110. [0036] The above wheeled apparatus 100 can travel on a ground by applying three modes of travel, namely, (1) by being pushed or pulled by an attendant; (2) by manually wheeling oneself when seated on the wheeled apparatus 100; or (3) by controlling a motor to propel the travel wheels 150. Now, FIGs. 17-21 are used to describe motions of the wheeled apparatus 100, exemplified by a wheelchair 100, being pushed or pulled over a step or kerb, which represents an uneven terrain. FIG. 17 shows the wheelchair 100 has reached a step 10 on the ground, and the travel wheels 150 come into contact with the step 10. When a pull force is applied onto the chassis 102 of the wheelchair 100, the pivot link members 105, 105a, 105b, 105c, 105d swing forward, against gravity G, as seen in FIG. 18; with the pivot link members 105,105a-105d being free to pivot about the pivot axes 110, 112, 112a, 112b, the mechanical effort of the pull force in mounting the travel wheels 150 over the step 10 is reduced; at the same time, the momentum of the wheelchair 100 also assists the wheelchair in mounting the step 10. Also with the pivot link members 105,105a- 105d, the locus of motion of the chassis 102 and the entire wheelchair 100, is smoother, that is, without the abrupt changes in motion experienced by the conventional wheelchair, as can be appreciated from the comparative FIGs. 5-6. In other words, the pivot link members 105,105a-105d provide damping on the motion of the wheeled apparatus 100, without having to provide any additional damping mechanism. In addition, the pivot link members 105,105a-105d do not affect the directions of motion of the wheelchair 100 when mounting the step 10, and thus motion along any curved trajectory can be executed unimpededly, just like when travelling on the conventional wheelchair.

[0037] When the pull force in FIG. 19 is continued, the travel wheels 150 are mounted completely over the step 10, as seen in FIG. 20, and in FIG. 21, the wheelchair 100 returns to the normal posture with both the travel wheels 150 and the front wheels 140 being supported on a level ground lying above the step 10. Recalling, with the present invention of the pivot link members 105,105a-105d, travelling on the wheeled apparatus 100 over a step or a kerb becomes smoother and requires lower mechanical efforts. In a reverse travel direction where the wheelchair 100 is being moved down a step 10, the pivot link members 105,105a-105d are also pivotable freely about the pivot axes 110, 112, 112a, 112b, thereby giving the same smoother locus of motion L3.

[0038] Now referring to active, powered motions of the wheeled apparatus 100, FIGs. 22-25 show the wheelchair 100 negotiating travel over a step 10. FIG. 22 shows the travel wheels 150 of the wheelchair 100 reach the step 10; when a drive force or torque is further applied on the travel wheels 150 in FIG. 23, the pivot link members 105,105a-105d react by swinging backward; swinging backwards of the pivot link members 105,105a-105d reduce the mechanical effort of the travel wheels in climbing over the step 10. Progressing further, the travel wheels 150 mount completely over the step, as seen in FIG. 24. In FIG. 25, the wheeled apparatus 100 is completely over the step 10, and it continues on its travel.

[0039] FIGs. 17-25 illustrate motions of the wheeled apparatus 100 mounting a step 10 or kerb. With illustration of FIG. 8, Inventors believe mounting of the wheeled apparatus 100 over a series of humps 11, which represent another form of uneven terrain, need no further description or illustration; as described and illustrated above, pivoting the chassis 102 of the wheeled apparatus 100 on the travel wheels 150 with the pivot link members 105, 105a- 105d provides a smoother ride, besides reducing the mechanical effort of mounting the wheeled apparatus 100 over an uneven terrain, especially over the stepped surface. The pivot link member of the present invention thus provides a useful mechanism to provide damping and reducing the mechanical effort of wheeling the apparatus over an uneven terrain; in addition, the pivot link member 105,105a-105d is relatively simple and is easy to install, maintain or replace.

[0040] FIGs. 26 and 27 illustrate exploded arrangements of the travel wheels 150, the pivot link members 105,105a-105d and a lower part of the chassis 102 of the wheeled apparatus 100. In FIG. 26, the chassis axle 104 is shown to be supported by a clamp member 160. The clamp member 160 is made up of two halves that are clamped to a lower portion of the chassis 102, preferably over T-joint members forming the chassis 102, as can be seen also in FIG. 2. For eg., the two halves of the clamp member 160 are assembled and are held together by securing means, such as, bolts and nuts, screws, and so on, that are removeable and allow easy re-assembly or maintenance; with this clamp member 160, the present invention can be retro-fitted onto a conventional wheel apparatus to provide a smoother travel motion over an uneven terrain.

[0041 ] It is also possible that a conventional wheeled apparatus can be adapted by fixing a chassis axle 104a permanently onto the chassis 102 of the wheeled apparatus 100. For eg., as seen in FIG. 27, the chassis axle 104a can be welded permanently on a lower part of the chassis 102. [0042] Even with the fixed chassis axle 104a, it is still possible to convert the wheeled apparatus 100 into a conventional apparatus by providing a wheel axle 152a for adaptable mounting with the previous chassis axle, now identified by numeral 103, already supplied on the conventional apparatus. In one embodiment, the wheel axle 152a can be supplied as a member of a kit of parts for adaptation.

[0043] FIG. 28 shows a pivot link member 105e according to yet another embodiment of the present invention. In FIG. 28, a lower end of the pivot link member 105e is offset outwardly, following spokes of the travel wheel 150 which are tapered outwardly. The pivot link member 105e is similar to the above pivot link member 105a or can be adapted therefrom.

[0044] It is also possible to convert the wheeled apparatus 100, albeit temporarily, to a conventional apparatus, for eg., when the wheeled apparatus 100 is being lifted for transport in a vehicle; in one embodiment, such a temporary conversion, is achieved by providing a clip-on interlock mechanism 180. FIGs. 3 and 29 show the clip-on interlock mechanism 180 can be used to fix or restrain movement of upper pivot axle 110 with respect to the chassis 102. In one embodiment, the clip-on brake 180 can be supplied as a member of the kit of parts for adaptation.

[0045] Without the clip-on interlock mechanism 180 on the pivot link member 105,105a- 105e, when a user lifts up the wheelchair 100 of the present invention, the pivot link member 105,105a-105e freely swings up to a substantially vertical position, as shown in FIG. 30; the free rotation of the pivot link member 105,105a-105e causes more difficulties for the user to lift up and to position the wheelchair 100 into a vehicle. With the clip-on interlock mechanism 180, the range of rotation alpha of the pivot link member 105,105a-105e is restrained, as illustrated in FIG. 31 ; as a result, with the clip-on interlock mechanism 180, the travel wheel 150 is restrained from drooping away from the chassis 102 when the wheelchair is lifted up (shown by arrows in FIGs. 30-31. In other words, the clip-on interlock mechanism 180 is a useful component to provide with the wheelchair 100.

[0046] FIG. 32 shows an interlock mechanism 180a on the pivot link member 105,105a-105e according to yet another embodiment of the present invention. As shown in FIG. 32, the interlock mechanism 180a is configured as a push-pull bar that is located co-axially with the axle 152 of the travel wheel 150. A proximal end of the interlock mechanism is equipped with a handle 181, whilst a distal end 182 is to be inserted into the (hollow) chassis axle 103 when the interlock mechanism 180a is put to use.

[0047] As described above, providing the kit of parts allow a user or a supplier to retrofit a conventional apparatus, to benefit from the advantages of the present invention. Reiterating, the kit of parts may comprise: the link member 105,105a-105e, the clamp member 160, the chassis axle 104, the weldable chassis axle 104a, the adaptable travel wheel axle 152a, the interlock mechanism 180,180a, frictionless bushings to fit the pivot axes 110,112,112a-112b of the pivot link member 105,1051-105e, bolt and nut sets, and so on. The chassis axle 104a may need to be welded to the chassis 102 by a skilled welder. It is also possible to provide the travel wheel axle 152a with a key way or splines, for eg., for coupling with a drive motor or a drive shaft.

[0048] While specific embodiments have been described and illustrated, it is understood that many changes, modifications, variations and combinations of variations disclosed in the text description and drawings thereof could be made to the present invention without departing from the scope of the present invention. For example, the pivot axes 112 may be provided with bushings or sleeves to reduce friction, or to reduce wear and tear on the chassis axle 104,104a; such bushings can also be used on the wheel axle 152,152a.

Claims

CLAIMS:

1. A wheeled apparatus for carrying a person or a load comprising: a travel wheel; a chassis axle of the wheeled apparatus; and a pivot link member, which is elongate and having two substantially parallel, offset axes located on two opposite ends, with a first axis being operable to journal with an axle of the travel wheel and a second axis being operable to journal with the chassis axle; wherein, when the wheeled apparatus travels over an uneven terrain, the pivot link member pivots about the two substantially parallel axes, thereby damping impact forces transmitted onto the wheeled apparatus, and providing a travel that is smoother and with lower mechanical efforts.

2. The wheeled apparatus according to claim 1 , wherein the second axis is configured with two or more substantially parallel axes at the nexus end of the pivot link member, so as to provide height adjustment for the wheeled apparatus.

3. The wheeled apparatus according to claim 1 , wherein the first axis is configured with two or more substantially parallel axes at the nexus end of the pivot link member, so as to provide a height adjustment for the wheeled apparatus.

4. The wheeled apparatus according to any one of claims 1-3, wherein the pivot link member is configured with a uniform thickness and a uniform width.

5. The wheeled apparatus according to any one of claims 1-3, wherein the pivot link member is configured with the opposite ends being non-uniform in thickness.

6. The wheeled apparatus according to claim 4, wherein a lower end of the pivot link member has a thickness more than a thickness of an upper end, such that centre lines of the upper end and the lower end are offset.

7. The wheeled apparatus according to any one of the preceding claims, wherein the pivot link member further comprises a hollow portion or aperture located between the substantially parallel axes, so as to reduce a weight of the pivot link member.

8. The wheeled apparatus according to any one of the preceding claims, further comprising an interlock mechanism, which is operable to fix or limit travel of an upper end of the pivot link member with respect to the chassis of the wheeled apparatus.

9. The wheeled apparatus according to claim 8, wherein the interlock mechanism is configured as a clip-on device.

10. The wheeled apparatus according to claim 8, wherein the interlock mechanism is configured as a push-pull bar being located coaxially with an axle of the travel wheel.

11. The wheeled apparatus according to any one of the preceding claims, further comprising a clamp member, which is operable to be fitted onto the chassis of the wheeled apparatus to support the chassis axle.

12. The wheeled apparatus according to any one of claims 1-10, wherein the chassis axle is operable to be fitted by welding onto the chassis of the wheeled apparatus.

13. The wheeled apparatus according to any one of the preceding claims, further comprising frictionless bushings that are operable to be fitted into the axes of the link member.

14. A wheeled apparatus for carrying a person or a load, the wheeled apparatus comprising: a kit of parts for retrofitting or adapting the wheeled apparatus defined in claims 1- 13, wherein the kit of parts comprises any combination of the following: a link member; a wheel axle; a chassis axle and an associated clamp member; a chassis axle for welding onto a chassis of the wheeled apparatus; frictionless bushings for fitting into the axes of the linked member; and an interlock mechanism member.

15. A method for improving impact dampening or smoothening of a wheeled apparatus when travelling on an uneven terrain, the method comprising: connecting a travel wheel to an axle of the wheeled apparatus with a pivot link member, wherein two substantially parallel, offset axes on opposite ends of the pivot link member are free to pivot and thus provide improved impact dampening or a smoother locus of motion.