GB2472426A

GB2472426A - Load handling equipment with slidably mounted third pair of wheels

Info

Publication number: GB2472426A
Application number: GB0913705A
Authority: GB
Inventors: Andrew Turner
Original assignee: SMARTCHAIR Ltd
Current assignee: SMARTCHAIR Ltd
Priority date: 2009-08-06
Filing date: 2009-08-06
Publication date: 2011-02-09
Also published as: GB0913705D0

Abstract

Load handling equipment, such as a patient transfer hoist or wheelchair, comprises a base 12,14 upon which three pairs of wheels are mounted; a first pair of wheel 2 at one end of the base, a second pair of wheel 4 at the other end, and an intermediate pair of wheel 6 which can slide between the first and second pairs from a position towards the front of the base [as shown in Figure 1] to a position towards the rear of the base [as shown in Figure 2]; wherein the base 12, 14 pivots about the third pair of wheels 6 such that the base is supported either by the first wheels 2 and the third wheels 6 when the third wheels are in a forward position, or supported by the third wheels 6 and the second wheels 4 when the third wheels are in a rearward position. Preferably, or in an alternative embodiment, the lateral separation between the second pair of wheels at the front of the base can be increased or decreased by movement of the third wheels in the fore and aft directions [as shown in Figures 3 and 4]. Preferably, arms 12,14 which form part of the base structure carry slide members that are fixed to and allow an axle carrying the third pair of wheels to slide along the base [22, Figures 6A-C].

Description

Load Handling Equipment This invention relates to load handling equipment.

Although the following description refers almost exclusively to load handling equipment in the form of a hoist or wheelchair arrangement for use with disabled or elderly people, it will be appreciated by persons skilled in the art that the present invention may be used to move various loads from a first location or position to a second location or position, such as movement of an animal, child, fragile articles or heavy articles and similar loads.

As is well understood by carers, hospital staff and the like, elderly, disabled, post-operative or otherwise mobility-impaired people frequently have difficulties undertaking simple mobility tasks that most able bodied people take for granted, for example, getting in and out of a vehicle, moving on and off a bed, a toilet, a chair etc. Frequently, a person suffering such mobility difficulties (hereinafter referred to as patient) has had to rely on a third party, such as a nurse or carer, to lift them and/or support them when moving from one location or position to a second location or position. Clearly, the movement of loads such as patients creates problems particularly relating to space availability for accomplishing the manoeuvre such as transfer into or out of a car. Such problems may be exacerbated depending upon the size of the load being manoeuvred, which, potentially, may give rise to an increase in the use of personnel to move the load and/or such personnel sustaining injury or strain. Additionally, many patients consider the need to be aided as undignified or degrading.

Previous attempts at overcoming the above problems include the provision of hoist or wheelchair to aid movement of the patient from one location or position to a different location or position. The patient is typically located in a support portion of the hoist or wheelchair and the support portion is moved between required positions.

A known hoist requires tracks to be fitted to a ceiling of a room in which the hoist is to be used, a part of the support portion moving on the tracks to allow the patient to be moved.

However, movement of the patient in the room is limited by the location of the tracks and such equipment is only usable in the room in which the tracks are fitted. Other known load handling equipment suitable for use with patients frequently require the equipment to be fitted at the location of use, for example a car hoist which is typically built into the car or a stair lift which is fitted to a wall adjacent the stairs.

Mobile load handling equipment in the form of wheelchairs are also known. Most wheelchairs are designed to move in a substantially horizontal direction across a floor surface, although some wheelchairs also have the capability to raise or lower the support or seat portion, thereby allowing the patient to undergo some level of vertical movement. However, this movement is fairly restrictive and does not allow a patient to be easily moved from the wheel chair into space-restricted locations, such as a car, onto a toilet seat etc. Examples of wheelchairs which may overcome some of these problems are shown in WO 2004/069125A and WO 2007/054721A.

In WO 2004/069125A, a load handling equipment which has a sling chair which may be raised or lowered and turned through 360° is described. The base has wheels for movement of the equipment across a floor, one of the rear wheels being capable of being rotated about a vertical axis to provide directional control of the equipment in limit spaces. The base frame of the equipment consists of two arms arranged in a fork and which are pivotally mounted on a support member for movement away from and towards one another between first positions in which they are parallel to one another and second positions in which they are at an angle to one another. This enables the ends of the arms remote from the support member to be moved apart to contribute to the stability of the equipment. However, this potential improvement in stability comes at the cost of requiring sufficient lateral clearance relative to the equipment for the arms to be so disposed.

In WO 2007/054721A, there is described a load handling equipment which has a chair or hoist or other load-carrying means. The equipment is movable on three pairs of wheels. Two pairs of the wheels are mounted on a lower frame portion which has two parallel arms, the pairs of wheels being mounted on opposite ends of the arms. The third pair of wheels is mounted on a axle slidably mounted on the arms for relative movement between a forward position near the front pair of wheels mounted on the arms and a rearward position near the rear pair of wheels mounted on the arms thus enabling the arms to be located beneath a bed or a car etc. The axle on which the third pair of wheels is mounted is longer than the distance between the arms whereby the third pair of wheels provides some lateral support to the equipment. In another embodiment, the arms may diverge from one another to provide additional lateral stability to the equipment. However, these potential improvements in stability come at the cost of requiring sufficient lateral clearance relative to the equipment to accommodate it.

It is an aim of the present invention to provide load handling equipment which is inexpensive to manufacture and which obviates or reduces the abovementioned problems.

It is a further aim of the present invention to provide a method of using movement apparatus.

According to a first aspect of the present invention, load handling equipment comprises a base structure on which are mounted three pairs of wheels whereby the equipment is movable over a surface on two of said pairs of wheels, a first pair of said pairs of wheels being mounted on a rear end of the base structure relative to motion of the equipment in a forward direction, a second pair of said pairs of wheels being mounted on a front end of the base structure relative to motion of said equipment in a forward direction, and a third pair of said pairs of wheels being slidably mounted on said base structure intermediate the first and second pairs of wheels for relative movement between a forward position near the second pair of wheels and a rearward position near the first pair of wheels, the configurations of each pair of wheels relative to one another being selected such that the base structure is pivotable relative to the third pair of wheels whereby, when the third pair of wheels is located in said forward position, the equipment is supported on a surface on which it is to be moved by the first and third pairs of wheels and, when the third pair of wheels is located in said rearward position, said equipment is supported on a surface on which it is to be moved by the second and third pairs of wheels.

As used in this specification in relation to the invention, the term "wheels" is intended to include any suitable wheel, roller and similar structure that will support the mass comprised by the equipment and any load intended to be carried on the equipment and which are suitable for traversing surfaces over which the equipment will be moved. For example, the wheels may be solid, spoked or of other construction and may have tyres, solid or pneumatic. Other examples of wheels which may be used for at least one pair of wheels are castor wheels (fixed or swivel), spherical wheels or Mecanum wheels.

Preferably, the base structure of the load handling equipment comprises a support structure and two elongate arms, the arms having first ends fixed relative to the support structure and second ends on which the second pair of wheels are mounted.

In a preferred embodiment, the arms are pivotally mounted on the support structure at or near their first ends whereby the arms are reciprocally movable between a first position in which the arms are generally parallel to one another and the wheels of said second pair of wheels are located in a first, inner position and a second position in which the arms diverge from one another towards their second ends and the wheels of said second pair are located in a second, outer position in which the wheels of said second pair are laterally more remote from one another as compared to the first position thereof. In their first position, the arms are described as being generally parallel by which is meant that the arms may be parallel to one another or may be close to being parallel, ie the arms may be at an angle of say up to 100, more preferably up to 5°, to a parallel position wherein the arms diverge slightly from one another from their first ends to their second ends.

Preferably, the base structure comprises slide members located on each arm and preferably lockable relative thereto, the third pair of wheels being rotatably mounted on the slide members.

Preferably, the slide members are linked together for simultaneous movement along the arms when not locked thereto. Although the third pair of wheels may be mounted one on each slide member by for example a stub axle extending laterally outwardly therefrom, preferably, the third pair of wheels is mounted on a common axle which is mounted transversely of the slide members and extends laterally outwardly from each slide member.

In a preferred embodiment, when the arms are movable between said first and second positions thereof the slide members are rotatably mounted on the common axle whereby the slide members may rotate in opposite directions about respective vertical axes during movement of the arms between said first and second positions.

As previously indicated, the configurations of each pair of wheels relative to one another being selected such that the base structure is pivotable relative to the third pair of wheels whereby when the third pair of wheels is located in said forward position, the equipment is supported on a surface on which it is to be moved by the first and third pairs of wheels and, when the third pair of wheels is located in said rearward position, said equipment is supported on a surface on which it is to be moved by the second and third pairs of wheels. The configurations of each pair of wheels relative to one another to achieve pivotal movement of the base structure relative to the third pair of wheels may be realised by selection of the size of each pair of wheels and/or the vertical separation of centres of rotation about which each pair of wheels rotate from a surface over which the equipment is to be moved.

Preferably, the base structure comprises brake means for braking at least the third pair of wheels.

Normal movement of the load handling equipment, which in preferred embodiments is a wheelchair or hoist mechanism for moving patients, between different locations may be achieved manually by a carer or nurse etc pushing the equipment or, alternatively, by power, typically by the use of electric motor(s) driving at least one of the wheels, preferably at least one of the first pair of wheels, either under control of a carer or nurse etc or of the patient. In this mode of operation, the load handling equipment is supported on a surface on which it is to be moved by the first and third pairs of wheels. When the patient is to be transferred to a bed or car etc, the load handling equipment is supported on the surface on which it is to be moved by the second and third pairs of wheels.

Movement of the third pair of wheels relative to the first and second pairs of wheels may be achieved manually or under power by applying the brake means to the third pair of wheels and unlocking the first slide members, either in sequence or simultaneously with the application of the brake means, and moving the first pair of wheels towards the third pair of wheels. In a preferred embodiment, when the arms are movable between said first and second positions thereof, said movement of the first pair of wheels towards the third pair of wheels also results in movement of the arms from their first, parallel position to their second, divergent position wherein the stability of the load handling equipment is improved.

During movement of the first pair of wheels towards the third pair of wheels, as the centre of gravity of the load handling equipment passes over the axle(s) carrying the third pair of wheels, owing to the size of each pair of wheels and/or the vertical separation of centres of rotation about which each pair of wheels rotate from a surface over which the equipment is to be moved being selected such that the base structure is pivotally rotatable relative to the third pair of wheels the base structure rotates about the third pair of wheels to transfer the mass of the load handling equipment from the first and third pairs of wheels to the second and third pairs of wheels.

In accordance with the invention, a variety of combinations of wheel sizes and/or vertical separation of centres of rotation about which each pair of wheels rotate from a surface over which the equipment is to be moved may be adopted to achieve the transfer the mass of the load handling equipment from the first and third pairs of wheels to the second and third pairs of wheels. In a preferred embodiment, however, the sizes of the wheels are selected such that the sizes, from largest to smallest, are selected as first pair > third pair > second pair. It will be apparent that, in this preferred embodiment, the vertical separation of the centres of rotation about which each pair of wheels rotate from a surface over which the equipment is to be moved, when the respective pairs of wheels are in contact with said surface, will similarly be, from the greatest to the smallest separation, in the order first pair > third pair > second pair.

It will be appreciated that, as the second pair of wheels are relatively small and hence have a small vertical separation from said surface, the load handling equipment according to the invention is particularly suitable for use in situations in which the space under furniture, such as beds or chairs, etc is particularly limited.

According to a second aspect of the present invention, load handling equipment comprises a base structure on which are mounted three pairs of wheels whereby the equipment is movable over a surface on at least two of said pairs of wheels, a first pair of said pairs of wheels being mounted on a rear end of the base structure relative to motion of the equipment in a forward direction, a second pair of said pairs of wheels being mounted on a front end of the base structure relative to motion of said equipment in a forward direction, the wheels of said second pair being reciprocally movable on the base structure between a first, inner position and a second, outer position in which the wheels of said second pair are laterally more remote from one another as compared to the first position, and a third pair of said pairs of wheels being slidably mounted on said base structure intermediate the first and second pairs of wheels for relative movement between a forward position near the second pair of wheels and a rearward position near the first pair of wheels, the mounting of the second and third pairs of wheels on the base structure being such that reciprocation of the third pair of wheels between said forward position, and said rearward position results in reciprocation of the wheels of said second pair between the first and second positions thereof.

The greater lateral separation of the wheels of said second pair achieves improved stability of the load handling structure when the third pair of wheels is located in its rearward position near the first pair of wheels.

Preferably, the base structure of the load handling equipment comprises a support structure and two elongate arms, the arms having first ends fixed relative to the support structure and second ends on which the second pair of wheels are mounted. The arms are pivotally mounted on the support structure at or near their first ends whereby the arms are reciprocally movable between a first position in which the arms are generally parallel to one another (as previously discussed) and a second position in which the arms diverge from one another towards their second ends thus achieving reciprocation of the wheels of said second pair between their first and second positions.

Although, in accordance with this second aspect of the invention, the load handling equipment may be supported relative to a surface over which it is to be moved by all three pairs of wheels, it is preferred that it is so supported by two of the three pairs of wheels in accordance with the first aspect of the invention.

In a preferred embodiment of the invention, the wheels of the first and third pairs of wheels have a similar or the same lateral separation from one another and the wheels of the third pair of wheels when in the second position thereof have a lateral separation no greater than the lateral separation of the first and third pairs of wheels. Thus, access of the load handling equipment to limited spaces is only limited by the lateral separation of the pairs of wheels. Preferably, wheels of the second pair of wheels are castors or other wheel configurations that permit multi-directional movement.

It will be appreciated that any feature of any aspect of any invention or embodiment described herein may be combined with any feature of any aspect of any other invention or embodiment described herein mu/a/is mu/andis.

In a preferred embodiment, the base structure of the load handling equipment according to the invention has an upper structure which may comprise any suitable load supporting means.

Preferably, however, the load handling equipment comprises load supporting means as described in WO 2007/054721A. Accordingly, WO 2007/054721A is incorporatcd hcrcin in its entirety by reference.

In one embodiment of the invention, only the base structure is pivotable relative to the third pair of wheels, the load supporting means being mounted on the base structure such that is remains substantially in the same attitude during said pivotable movement. Alternatively, the load supporting means is mounted on the base structure such that the base structure together with the load supporting means is pivotable relative to the third pair of wheels.

Thus, the load handling equipment according to the present invention, especially in the form of a wheelchair or hoist mechanism for moving patients between different locations, is capable of providing movements of a patient support thereon in different directions defined by various axes as described in WO 2007/054721A.

The invention will now be described, by way of example only, with reference to abd as illustrated in the accompanying diagrammatic drawings, in which: Figures 1 and 2 are schematic side views of the wheel arrangement of load handling equipment in accordance with the present invention in first and second configurations; Figures 3 and 4 are respectively corresponding schematic plan views of the wheel arrangement shown in Figures 1 and 2; Figure 5 is a schematic representation of a pivot joint for part of the equipment; and Figures 6A and 6B are schematic plan views of one embodiment of the third pair of wheels in accordance with the present invention in first and second configurations and Figure 6C is an end elevation partly in section of the third pair of wheels.

Load handling equipment according to the invention has a base structure on which are mounted wheels by which the equipment may be moved over a surface. The base structure carries an upper structure which includes load carrying means. In a preferred embodiment, the equipment is a wheelchair and the load carrying means is in the form of a chair seat or hoist or a stretcher. Details of suitable constructions of the upper structure and load carrying means may be found by reference to WO 2007/054721A.

Referring now to the drawings, the base structure has a support structure (not shown) on which are mount three pairs of wheels 2, 4, 6 by which the equipment may be moved over a surface 8.

The first pair of wheels 2 have a common axle 10 carried by the support structure at the rear of the equipment.

The support structure has two generally horizontal arms 12, 14 extending therefrom towards the front of the equipment. The arms 12, 14 are pivotally attached to the support structure at first ends thereof and carry the wheels of the second pair of wheels 4 at their second ends. The pivot attachment of the arms 12, 14 to the support structure may be a simple pivot joint as shown in Figure 5 wherein a bracket 16 on the support structure carries a pivot pin (represented by the pivot axis 18) which extends through the end of the arm 12, 14.

The third pair of wheels 6 is mounted on a common axle 20 in which is mounted slide members 22 for rotation (as indicated by arrow 24) about respective vertical axes (see Figures 6A to 6C). Each slide member 22 has a circular body 26 through which passes a channel 28 for receiving a respective arm 12, 14 (represented by chain dot centre lines in Figures 6A to 6C) in sliding engagement with the channel 28. The slide members 22 each sit in a respective part-circular recess 30 in the common axle 20. The slide members 22 also each have a pivot pin 32 which extends through a corresponding bore 34 in the axle 20 at the centre of the base of each recess 30 and are retained relative to the axle 20 by respective locking members 36. In one embodiment, the slide members 22 are lockable relative to the arms 12, 14. The common axle 20 links the slide members 22 together for simultaneous movement along the arms 12, 14 when not locked thereto.

As shown in the drawings, the sizes of the wheels are selected such that the sizes, from largest to smallest, are selected as first pair 2 > third pair 6 > second pair 4. It will be apparent that the vertical separation of the centres of rotation about which each pair of wheels 2, 4, 6 rotate from the surface 8, when the respective pairs of wheels 2, 4, 6 are in contact with the surface 8, will similarly be, from the greatest to the smallest separation, in the order first pair 2 > third pair 6 > second pair 4.

In use, the pairs of wheels 2, 4, 6 occupy one of two configurations as shown in Figures 1 and 3 and Figures 2 and 4, respectively.

Normal movement of the load handling equipment between different locations may be achieved manually by a carer or nurse etc pushing the equipment or, alternatively, by power, typically by the use of electric motor(s) driving at least one of the wheels, preferably at least one of the first pair of wheels 2, either under control of a carer or nurse etc or of the patient. In this mode of operation, the load handling equipment is in a first configuration as shown in Figures 1 and 3 and is supported on the surface 8 by the first and third pairs of wheels 2, 6. When the patient is to be transferred to a bed or car etc, the load handling equipment is supported on the surface 8 by the second and third pairs of wheels 4, 6.

Movement of the third pair of wheels 6 relative to the first and second pairs of wheels 2, 4 to convert the wheel pairs 2, 4, 6 into the second configuration shown in Figures 2 and 4 may be achieved manually or under power by applying a brake means (not shown) to the third pair of wheels 6 and unlocking the slide members 22 from the arms 12, 14, either in sequence or simultaneously with the application of the brake means, and moving the first pair of wheels 2 towards the third pair of wheels 6. The movement of the first pair of wheels 2 towards the third pair of wheels 6 also results in movement of the arms 12, 14 from their first, generally parallel position (Figures 1 and 3) to a second, divergent position (Figures 2 and 4). During such movement, the slide members 22 pivot about their respective vertical axes in opposite directions on the axle 20 to accommodate the increasing divergence between the arms 12, 14.

During movement of the first pair of wheels 2 towards the third pair of wheels 6, as the centre of gravity of the load handling equipment passes over the axle 20 carrying the third pair of wheels 6, owing to the size of each pair of wheels 2, 4, 6 and the vertical separation of centres of rotation about which each pair of wheels 2, 4, 6 rotate from the surface 8 being such that the base structure is pivotally rotatable relative to the third pair of wheels 6, the base structure rotates about the third pair of wheels 6 to transfer the mass of the load handling equipment from the first and third pairs of wheels 2, 6 to the second and third pairs of wheels 4, 6.

It will be appreciated that, as the second pair of wheels 4 are relatively small and hence have a small vertical separation from the surface 8, the load handling equipment according to the invention is particularly suitable for use in situations in which the space under furniture, such as beds or chairs, etc is particularly limited.

The greater lateral separation of the wheels of said second pair 4 in the second configuration (Figures 2 and 4) achieves improved stability of the load handling structure when the third pair of wheels 6 is located in its rearward position near the first pair of wheels 4.

As shown in the drawings, the wheels of the first and third pairs of wheels 2, 6 have a similar or the same lateral separation from one another and the wheels of the third pair of wheels 4 when in the second position thereof have a lateral separation no greater than the lateral separation of the first and third pairs of wheels 2, 6. Thus, access of the load handling equipment to limited spaces is only limited by the lateral separation of the pairs of wheels. Preferably, the wheels of the second pair of wheels 2 are castors or other wheel configurations that permit multi-directional movement.

It will be appreciated that, provided the basic operation of the wheel pairs of the load handling equipment according to the invention is achieved, the physical arrangements to achieve that end may differ from those specifically illustrated and such variations are within the scope of the invention as claimed herein.

Claims

Claims 1. Load handling equipment comprising a base structure on which are mounted three pairs of wheels whereby the equipment is movable over a surface on two of said pairs of wheels, a first pair of said pairs of wheels being mounted on a rear end of the base structure relative to motion of the equipment in a forward direction, a second pair of said pairs of wheels being mounted on a front end of the base structure relative to motion of said equipment in a forward direction, and a third pair of said pairs of wheels being slidably mounted on said base structure intermediate the first and second pairs of wheels for relative movement between a forward position near the second pair of wheels and a rearward position near the first pair of wheels, the configurations of each pair of wheels relative to one another being selected such that the base structure is pivotable relative to the third pair of wheels whereby, when the third pair of wheels is located in said forward position, the equipment is supported on a surface on which it is to be moved by the first and third pairs of wheels and, when the third pair of wheels is located in said rearward position, said equipment is supported on a surface on which it is to be moved by the second and third pairs of wheels.
2. Load handling equipment according to claim I wherein the base structure of the load handling equipment comprises a support structure and two elongate arms, the arms having first ends fixed relative to the support structure and second ends on which the second pair of wheels are mounted.
3. Load handling equipment according to claim 2 wherein the arms are pivotally mounted on the support structure at or near their first ends whereby the arms are reciprocally movable between a first position in which the arms are generally parallel to one another and the wheels of said second pair of wheels are located in a first, inner position and a second position in which the arms diverge from one another towards their second ends and the wheels of said second pair are located in a second, outer position in which the wheels of said second pair are laterally more remote from one another as compared to the first position thereof.
4. Load handling equipment according to claim 2 or claim 3 wherein the base structure comprises slide members located on each arm and lockable relative thereto, the third pair of wheels being rotatably mounted on the slide members.
5. Load handling equipment according to claim 4 wherein the slide members are linked together for simultaneous movement along the arms when not locked thereto.
6. Load handling equipment according to claim 4 or claim 5 wherein the third pair of wheels is mounted on a common axle which is mounted transversely of the slide members and extends laterally outwardly from each slide member.
7. Load handling equipment according to claim 6 when dependent on claim 3 wherein the slide members are pivotally mounted on the common axle whereby the slide members may rotate in opposite directions about respective vertical axes during movement of the arms between said first and second positions.
8. Load handling equipment according to any one of the preceding claims wherein the sizes of the wheels are selected such that the sizes, from largest to smallest, are selected as first pair > third pair > second pair and the vertical separation of the centres of rotation about which each pair of wheels rotate from a surface over which the equipment is to be moved, when the respective pairs of wheels are in contact with said surface, are selected to be, from the greatest to the smallest separation, in the order first pair > third pair > second pair.
9. Load handling equipment comprising a base structure on which are mounted three pairs of wheels whereby the equipment is movable over a surface on at least two of said pairs of wheels, a first pair of said pairs of wheels being mounted on a rear end of the base structure relative to motion of the equipment in a forward direction, a second pair of said pairs of wheels being mounted on a front end of the base structure relative to motion of said equipment in a forward direction, the wheels of said second pair being reciprocally movable on the base structure between a first, inner position and a second, outer position in which the wheels of said second pair are laterally more remote from one another as compared to the first position, and a third pair of said pairs of wheels being slidably mounted on said base structure intermediate the first and second pairs of wheels for relative movement between a forward position near the second pair of wheels and a rearward position near the first pair of wheels, the mounting of the second and third pairs of wheels on the base structure being such that reciprocation of the third pair of wheels between said forward position, and said rearward position results in reciprocation of the wheels of said second pair between the first and second positions thereof.
10. Load handling equipment according to claim 10 wherein the base structure of the load handling equipment comprises a support structure and two elongate arms, the arms having first ends fixed relative to the support structure and second ends on which the second pair of wheels are mounted, the arms being pivotally mounted on the support structure at or near their first ends whereby the arms are reciprocally movable between a first position in which the arms are generally parallel to one another and a second position in which the arms diverge from one another towards their second ends thus achieving reciprocation of the wheels of said second pair between their first and second positions.
11. Load handling equipment according to any one of the preceding claims wherein the wheels of the first and third pairs of wheels have a similar or the same lateral separation from one another and the wheels of the third pair of wheels when in the second position thereof have a lateral separation no greater than the lateral separation of the first and third pairs of wheels.