GB2072139A

GB2072139A - Invalid hoists

Info

Publication number: GB2072139A
Application number: GB8109053A
Authority: GB
Original assignee: James Investments Ltd
Current assignee: James Investments Ltd
Priority date: 1980-03-25
Filing date: 1981-03-23
Publication date: 1981-09-30
Also published as: DE3111750A1

Abstract

An invalid hoist for positioning at the side of a hydrotherapy pool or tank comprises a wheeled base frame 20 located relative to the pool or tank by means of a ground anchorage point 30. The frame 20 supports an upstanding column 10 from which a load support arm 11 projects forwardly so as to extend over the pool or tank, this arm carrying a patient support member 25. The column 10 is positioned towards the rear of the frame 20 which has a front castor wheel 26 and two fixed axis wheels 27 and 18 with a common axis which passes through the anchorage point 30. The hoist can be wheeled to and from the pool and, when anchored, pivoted on the three wheels 26, 27 and 28 about the anchorage point 30 to swing the arm 11 in a horizontal plane to and from a patient loading/unloading position alongside the pool or tank. <IMAGE>

Description

SPECIFICATION Invalid hoists This invention relates to so called "invalid hoists" for raising and lowering infirm and disabled persons. It is specifically concerned with invalid hoists of the type adapted for use in the field of hydrotherapy and comprising a base for positioning alongside a hydrotherapy pool or tank and a load support arm which projects to reach over the edge of the pool or tank and support a person suspended therein during treatment.

An invalid hoist of the foregoing type, hereinafter for convenience referred to as a "hydrotherapy hoist" although it is as will be appreciated generally useful for providing access to a swimming pool for disabled persons, usually has a base mounting plate which has to be fixed some distance from the edge of a pool to provide firm ground for the fixing bolts, requiring a long cantilevered load support arm. The length of this arm results in large bending moments which the column and base have to withstand. These large bending moments in turn result in a high loading of the fixing bolts, thereby increasing the problems of achieving firm fixing reasonably close to the edge of the pool.

The arm of a hydrotherapy hoist commonly projects from an upstanding column and it is necessary for the arm to swing round between an operative position extending over the pool or tank, in which a patient support member carrying the patient can be lowered into the water and raised therefrom, and a position clear of the pool or tank at which the patient can be placed on or removed from the support member. To this end such hydrotherapy hoists at present have a rotary bearing at the column which presents problems not only with regard to the heavy bending load which the bearing has to sustain due to the long load support arm but also resulting from the unfavourable working environment provided by a humid atmosphere and the likelihood of being splashed with water.When a swimming pool is used for hydrotherapy sessions the bearing also has to operate in a chlorine-laden atmosphere, and in this case the hoist normally has to be removable so that it can be stored out of the way when not in use. To this end the columns of hydrotherapy hoists have been formed to fit into a socket mounting in a base plate, or a sunken mounting socket, fixed to the floor. It is then difficult to keep the socket clean and sealed when not in use, there are difficulties in handling the heavy hoist when removed from the socket, and the appropriately massive base plate presents a floor obstruction when the hoist is removed.

The object of the invention is to provide a hydrotherapy hoist which materially overcomes the foregoing disadvantages and problems. In particular, it has for an object to provide a hoist which is readily transferable to and from a hydrotherapy pool or tank, and which does not require a rotary bearing for the cantilevered support arm to allow the necessary swinging movement of the arm. Further objects are to provide a hoist which is more easily anchored to the ground without the problems associated with the fixing of present hydrotherapy hoists.

According to the invention a hydrotherapy hoist, for positioning at the side of a pool or tank, comprises a wheeled base frame adapted to be located relative to the pool or tank by means of a ground anchorage point and supporting an upstanding column from which a load support arm projects forwardly so as to extend over the pool or tank, the base frame having at least two groundsupport wheels respectively positioned in plan view on opposite sides of the longitudinal axis of the load support arm and which enable the hoist to be wheeled to and from the pool or tank and to be turned about the anchorage point to swing the load support arm in a horizontal plane to a patient loading/unloading position alongside the pool or tank.

A lifting mechanism may be provided by which the arm can be raised and lowered relative to the column, but it is preferred that the lifting mechanism should be in accordance with our Patent No. 1,448,012 in which the arm does not move relative to the column in order to lift the patient but instead the latter is supported on a rigid elongated load support member which can be raised and lowered in a vertical plane while slidably guided by guide means at the end of the column.

Said two wheels may be fixed-axis wheels or castors, and preferably at least three groundsupport wheels are provided so that the hoist is self supporting and applies no vertical loading on the anchorage. Preferably the construction and weight distribution are such that when the hoist is loaded it is stable and adequately supported at all times by the ground-support wheels, without any upward pull or bending moment applied to the anchorage. Thus the latter merely has to provide a simple vertical pivot.

The frame may be of symmetrical and generally triangular form in plan view, somewhat elongated with the shortest side of the triangle providing the front edge of the frame and the two firstmentioned wheels mounted adjacent the two front corners. The anchorage point may then be disposed adjacent the rear apex of the triangle and a castor providing the third ground-support wheel may be positioned adjacent the anchorage point.

Alternatively, the frame may comprise three limbs which radiate outwardly from a column support of the frame, and adjacent the ends of which the ground-support wheels are mounted.

One such limb may extend forwardly directly beneath the load support arm, with the other two on which the two first-mentioned wheels are mounted extending to the side and preferably slightly rearwardly. A fourth limb may extend rearwardly and provide the anchorage point, in which case said other two limbs preferably mount the two corresponding wheels so that they are disposed on a lateral axis which passes through the pivot axis defined by the anchorage.

A single fixed-axis wheel or castor may be mounted at the end of the forwardly projecting limb, although this may be replaced by an equivalent arrangement of two spaced wheels mounted on a cross member at the end of this limb.

A hoist in accordance with the invention can be used with the track of the front wheel or wheels, as the hoist is swung round about the anchorage point, passing very close to the edge of the tank or pool thus enabling the length of the arm to be kept to a minimum. The fore-and-aft length of the chassis can be of any desired dimension, and in particular it can be of adequate length to present no problems in finding firm ground for the anchorage which need merely be a simple threaded socket to receive an anchorage bolt passing through a bearing at the rear of the frame.

At least one of the ground-support wheels is braked to prevent unintentional rotation of the hoist about the anchorage point, preferably employing a castor of the friction-loading type with a foot-operated locking mechanism which locks both the swivel axis and the wheel axis of the castor The invention will now be further described with reference to the accompanying drawings which somewhat diagrammatically illustrate, by way of example, two embodiments of the invention. In the drawings: Figure 1 is a side view of one embodiment shown in operative position alongside a swimming pool; Figure 2 is a corresponding plan view; Figure 3 is a perspective view of the other embodiment; and Figure 4 is a plan view thereof.

The hydrotherapy hoist illustrated in Figures 1 and 2 of the drawings comprises a base frame 1 in the form of a wheeled chassis having a somewhat elongated triangular framework of a symmetrical plan form. Adjacent a rear apex of the triangle the base frame 1 is supported on a castor 2 and adjacent the two ends of a front shorter side of the base the latter is supported on fixed-axis wheels 3.

The castor 2 and wheels 3 enable the hoist to be wheeled to and from the hydrotherapy pool 4, and to this end the front wheels 3 can be locked in one set position (shown in broken lines in Figure 2) in which the wheels are coaxial with the fixed horizontal common axis thereof perpendicular to the central symmetrical fore-and-aft axis 5 of the base 1. When positioned alongside the pool 4 the hoist is anchored at an anchorage point just behind the castor 2 adjacent the rear apex of the base frame 1.

The anchorage point is provided by a bearing block 6 at said rear anchorage point through which a vertical anchor bolt 7 passes, this bolt being screwed into a simple threaded socket 8 grouted into the ground and providing a firm anchorage about which the hoist can be swung around the vertical bolt axis. The socket 8 is slightly recessed into the ground, and when not in use a sealing cap (not shown) can be screwed into the socket 8 and is then flush with the ground surface.

To enable the hoist to be swung from the operative position shown to a loading and unloading position alongside the pool 4, the front wheels 3 can be set in an alternative operative position (shown in full lines in Figure 2) in which the fixed horizontal axes thereof are convergent and intersect at the bolt 7, i.e. the wheels 3 are tangential to their circular path of movement 9 about the bolt axis. This path 9, as clearly shown in Figure 2, can pass close to the edge of the pool 4. This enables the hoist to be anchored and used right up to the pool edge although the anchorage 8 is positioned well back in firm ground, thus avoiding the anchorage problems commonly met with when fixing existing hoists.

The hoist also comprises an upstanding column 10 mounted centrally at the front of the frame 1, and a load support arm 11 fixed to the top of the column 10. This arm 11 projects forwardly beyond the front edge of the base 1 with a longitudinal axis disposed directly above the axis 5, so as to project over the pool as shown in the drawings when the hoist is operatively positioned and anchored. As the hoist swings as a whole about the anchorage bolt 7 the arm 11 can be rigidly fixed to the column 10 and does not rotate relatively thereto, so that the expensive and problem-causing prior bearing arrangements are not required.The arm 11 supports an elongated load support member 12 which can be raised and lowered, in vertical guide 13 means mounted at the outer end of the arm 11, by a mechanical lifting mechanism controlled manually by a winding handle 14 at the top of the column 10.

This enables a patient, on a patient support 1 5 cantilevered at the bottom end of the support member 12, to be lowered into the pool 4 or raised therefrom. The patient support is preferably detached from the support member 12 and may be in the form of a legless chair or stretcher frame, the latter being illustrated in Figure 2.

The manually operated mechanism may be replaced by a motorised unit (not shown) incorporating a low-voltage electrical driving motor energised by a battery. The latter may be a heavy-duty 12 volt car battery mounted on a platform at the top of the column or on the frame 1 to provide a self-contained motorised hoist.

When the patient is supported on the support 1 5 above the level of the pool edge the hoist as a whole can be swung about the bolt 7 to allow loading and unloading of the patient clear of the pool. When the support 1 5 is detachable it may be adapted for alternative fixing to a wheeled trolley to enable the patient to be wheeled to and from the hoist on the patient support 1 5.

As the hoist can be operatively positioned and anchored close to the pool edge the cantilever projection of the support arm 11 can be of minimum length. This enables the arm to be of a lighter and cheaper construction than hitherto and also reduces the vertical load withstood by the anchorage. In fact, the short arm 11 and the length of the chassis frame 1 in this embodiment provides a moment relationship such that only a small vertical pull has to be withstood by the anchorage 8 which, as will be appreciated, is not subject to any material horizontal force. This further overcomes the anchorage problems common to existing hoists.

In a modification of the embodiment of Figures 1 and 2 the two front wheels 3, with fixed axes settable in alternative positions as described, are replaced by two castor wheels. These are of known type with foot-operated friction-braking means so that they can be locked in respect of both the castor pivot axis and the castor wheel axes. When so locked they prevent undesired movement of the hoist when in use.

The column 10, load support arm 11 and lifting mechanism of the second embodiment of Figures 3 and 4 are generally as already described, except that in this case an arm 11 of increased length is required as the column 10 is mounted adjacent the rear of the base frame 20. In this case the frame 20 is triangulated and comprises three limbs 21, 22 and 23 which radiate outwardly from a boss 24 providing a column support of the base frame. The patient support member illustrated with this embodiment is the alternative form of legless chair construction 25, previously referred to.

The limb 21 of the base frame 20 extends forwardly directly beneath the arm 11, the latter and the column being omitted from Figure 4 to show clearly the changed construction of the base frame 20. A castor 26 providing a ground-support wheel is mounted at the outer end of the limb 21.

The limbs 22 and 23 extend sidewards and slightly rearwardly, being symmetrically disposed with respect to the fore-and-aft axis 5 of the base frame 20. Two rear ground-support wheels 27 and 28 are respectively mounted at the ends of the limbs 22 and 23, and these are of fixed-axis type mounted coaxially on the respective limbs 22 and 23. A short fourth limb 29 extends directly rearwardly from the column support boss 24, and this limb provides the anchorage point 30 which is now disposed a relatively short distance behind the column 10.

The anchorage point is positioned so that it provides a vertical pivot axis which intersects the common axis 32 of the rear wheels 27 and 28.

Although this embodiment has a longer arm 11, and thus the column 10 and arm 11 have to be constructed to withstand greater bending moments, in comparison with the first embodiment the second construction provides increased stability and imposes even less stress on the floor anchorage. The design enables the hoist to be completely self-supporting on the groundsupport wheels, the rear wheel track and the overall weight distribution being such that no vertical loading whatever, either downward or upward, is in use applied to the anchorage which is thus merely a simple pivot arrangement. The hoist can easily be wheeled to and from the pool on all three ground-support wheels 26, 27 and 28, during which the aforesaid weight distribution assists in providing a high degree of stability and manoeuvrability.

In a modification of the second embodiment, which is not illustrated, the single front wheel 26 is replaced by two wheels mounted at opposite ends of a short cross member fixed at the outer end of the front limb 21. This reduces the individual wheel and hence ground loading at the front end of the base frame 20, enabling the path of the front wheel to come very close to the edge of the pool and hence assisting in the location of the hoist near to the pool.

The second embodiment, with a very narrow base frame structure beneath the arm 11, is particularly easy to turn by hand about the anchorage point 30. To assist this a projecting handle 31 may be fixed to the side of the arm 11.

It will be appreciated that the front wheel 26 may be a braked castor or a fixed-axis wheel the axis of which is settable in either of two directions as described in connection with the front wheels of the first embodiment.

Claims

1. An invalid hoist, for positioning at the side of a pool or tank, comprising a wheeled base frame adapted to be located relative to the pool or tank by means of a ground anchorage point and supporting an upstanding column from which a load support arm projects forwardly so as to extend over the pool or tank, the base frame having at least two ground-support wheels respectively positioned in plan view on opposite sides of the longitudinal axis of the load support arm and which enable the hoist to be wheeled to and from the pool or tank and, when in use, to be turned about the anchorage point to swing the load support arm in a horizontal plane to and from a patient loading/unloading position alongside the pool or tank.

2. An invalid hoist according to claim 1, wherein the load support arm is fixed relative to the column and a lifting mechanism is operative to raise and lower a rigid elongated load support member which is slidably guided by guide means at the end of the arm.

3. An invalid hoist according to either one of the preceding claims, wherein at least three ground-support wheels are provided so that the hoist is self-supporting while wheeled thereon and in use imposes no downward vertical loading on the ground anchorage point.

4. An invalid hoist according to claim 3, wherein the construction and weight distribution are such that when the hoist is loaded it is stable and at all times adequately supported by the ground-support wheels, without any upward vertical loading or bending moment being applied to the ground anchorage point which thus merely provides a simple vertical pivot.

5. An invalid hoist according to claim 3 or 4, wherein the base frame is of triangular or triangulated form in plan view.

6. An invalid hoist according to any one of the preceding claims, wherein said ground anchorage point is located adjacent the rear of the base frame.

7. An invalid hoist according to claims 5 and 6, wherein the base frame is of triangular form, somewhat elongated with the shortest side of the triangle providing a front edge of the frame and said two ground-support wheels mounted adjacent the two front corners of the frame, said anchorage point being adjacent the rear apex of the triangle with the column mounted adjacent the front of the frame.

8. An invalid hoist according to claims 5 and 6, wherein the base frame is triangulated and comprises three limbs which radiate outwardly from a column support portion of the frame, the ground-support wheels being mounted adjacent the outer ends of the three limbs.

9. An invalid hoist according to claim 8, wherein one of said limbs extends forwardly directly beneath the load support arm, and the other two limbs on which said two ground-support wheels are respectively mounted extend symmetrically to the sides of the column mounting.

10. An invalid hoist according to claim 9, wherein the column is mounted towards the rear of the base frame and a fourth relatively short limb extends rearwardly from said column mounting and provides the anchorage point, said sidewardly extending limbs extending also rearwardly to mount said two ground-engaging wheels on a iateral axis which passes through the pivot axis defined by the anchorage point.

11. An invalid hoist according to claim 10, wherein said two ground-support wheels mounted on the sidewardly and rearwardly extending limbs are coaxial fixed-axis wheels.

12. An invalid hoist according to any one of claims 9 to 11, wherein a single fixed-axis wheel or castor is mounted at the end of said forwardlyprojecting limb.

13. An invalid hoist according to any one of the preceding claims, wherein a wheel (or wheels) mounted at the front end of the base frame comprises a castor (or castors) which can be braked or a fixed-axis wheel (or wheels) the axis of which is settable in alternative positions respectively disposed radially of the anchorage point or tangentially of a circular arch centred on the anchorage point.

14. An invalid hoist constructed and arranged substantially as herein particuiarly described with reference to and as illustrated in Figures 1 and 2, or Figures 3 and 4, of the accompanying drawings.