GB2120633A - Access apparatus - Google Patents

Abstract

An access platform (13) is mounted on an articulated arm (12) carried on a body (10) for movement about a vertical axis. The body is less than one metre wide and is provided with extensible legs (11) movable between the operative positions shown and inoperative positions by pivoting relative to the body upwardly and downwardly. <IMAGE>

Description

SPECIFICATION Movable platform apparatus DESCRIPTION OF INVENTION This invention relates to apparatus comprising a body which stands on the ground in use and a platform which can be moved relative to the body and can support a person whilst working above ground level.

Apparatus according to the invention comprises a body having a plurality of legs for engaging the ground, an arm mounted on the body for movement relative thereto and a platform carried on the arm, wherein the legs can be moved relative to the body between operative positions and inoperative positions.

Movable apparatus which is required to support a person working above ground level must possess sufficient stability to ensure that the apparatus does not tip when a platform bearing the person is moved to the limit of.its range of movement. Two alternative arrangements have been adopted in known apparatus capable of lifting a person other than vertically to a working position above the ground, in order to provide the required stability. In the first of these arrangements, a counterweight is provided at a position such that, to be effective, the counterweight has to be massive, compared with the weight of the person to be supported on the platform. In the second known arrangement, apparatus including an arm carrying the platform is mounted on a relatively massive vehicle.

Adoption of these arrangements severely limits the usefulness of the apparatus in places to which access at ground level is restricted, for example places which can be approached only through doorways or along passages.

The configuration of apparatus according to the present invention when the legs are in their respective operative positions and the platform is at the limit of its lateral movement from the body is preferably such that no balast is required during use of the apparatus. By "balast" we mean a counterweight or other element of the apparatus which is provided either for the sole purpose of increasing the weight of the apparatus relative to that of the person who is to work on the platform or which, although it has some additional function in the apparatus, has a more massive form than is necessary merely to carry out that other function and is selected to contribute significantly to the weight of the apparatus.It is an optional feature of the present invention that stability is achieved by the configuration of the machine, when in use, rather than by the incorporation of heavy elements in the apparatus.

It is also preferred that the body has a width less than 0.9 metre and that, when in their inoperative positions, the legs do not project from the body in such a manner as to increase the overall width of the apparatus beyond this value.

The legs may be detachable from the body but we prefer that the legs remain attached to the body when in their inoperative positions.

An example of apparatus in accordance with the invention will now be described, with reference to the accompanying drawings wherein: FIGURE 1 shows a perspective view of the apparatus in a configuration in which the apparatus is used, FIGURE 2 shows a part of the apparatus of Figure 1 with a leg in an inoperative position; and FIGURE 3 illustrates a modification of the apparatus of Figure 1.

The apparatus illustrated in Figures 1 and 2 includes a body 10 provided with legs 11 which support the body above the ground when the apparatus is in use. In the example illustrated, there are four legs but a smaller or larger number of legs may be provided. An articulated arm 1 2 is mounted on the body and carries at its free end a platform 13 suitable for supporting a person. The platform includes a floor which is maintained at least approximately horizontal in use and further includes side walls or rails to prevent a user stepping inadvertently off the floor.

Each of the legs 11 illustrated in Figure 1 comprises two relatively removable parts 1 4 and 1 5 arranged telescopically. Known means is provided for maintaining the leg in the extended configuration illustrated in Figure 1. For example, there may be provided a pin which can be inserted through aligned holes in the two parts of the leg.

On that part of the leg which is remote from the body 10, there is provided a foot 1 6 which rests on the ground and covers an area of the ground considerably greater than the cross-sectional area of the leg in a horizontal plane. The foot may be pivoted on the inner leg part 1 5. If required, each leg may comprise a larger number of telescopically arranged parts.

Each leg 11 is mounted on the body 10 by means of a respective pivot 1 7 for movement relative to the body between the operative position shown in Figure 1 and the inoperative position shown in Figure 2. Means is provided for releasably securing the leg in each of these positions. For example, a further pin which can be inserted through aligned holes in the leg and an adjacent part of the body may be provided. The axis defined by each pivot 1 7 is substantially horizontal when the apparatus stands on a horizontal surface. In their operative positions, the legs each extend downwardly and outwardly from the body. In the inoperative positions, the legs extend upwardly from the pivots 1 7 but do not extend outwardly significantly beyond the pivots.

As shown in Figure 2, the preferred inoperative positions are such that the legs extend upwardly and inwardly from the pivots.

The body 10 includes a turret 1 8 provided with a bearing for supporting a mounting member 19 for rotation relative to the body about an axis which is substantially upright when the apparatus is in use. A motor 20, preferably an electric motor, is provided for turning the mounting member relative to the body. The arrangement may be such that the motor can turn the mounting member through a complete revolution relative to the body. Alternatively, the arrangement may be such that turning of the mounting member relative to the body is limited to an angle less than 3600.

The motor 20 may be an hydraulic motor supplied with fluid from a pump also used to operate rams hereinafter described.

The arm 12 comprises two mutually articulated limbs, a lower limb 21 and an upper limb 22. The lower limb 21 is mounted, adjacent to one of its ends, on the mounting member 19 by means of a pivot 23 which is perpendicular to the axis of rotation of the mounting member relative to the body. For controlling pivoting of the lower limb relative to the body there is provided an hydraulic ram 24 connected between the mounting member and the lower limb, in each case at a position spaced from the pivot 23. The platform 13 is connected with the upper limb 22 adjacent to one end thereof for pivoting about an axis parallel to the axis defined by the pivot 23.The upper limb 22 is connected adjacent to its end remote from the platform 13 with the lower limb 21 at its end remote from the mounting member 19 in such amanner that limited relative pivoting of the limbs can occur under the control of a further hydraulic ram 25 connected to the limbs. The pivotal connection 31 between the limbs is preferably so arranged that the upper limb 22 can rest on an upper surface of the lower limb 21.

Pivoting of the platform 1 3 relative to the upper limb 22 is controlled in a known manner by rods 26 and 27 which provide a connection between the mounting member 19, the pivot 31 and the platform 13 to ensure that the floor of the platform remains substantially horizontal when the platform is raised and lowered.

For supplying hydraulic fluid to the rams 24 and 25, there is provided an electrically driven pump 28 which is mounted on the body 10. Means for controlling the supply of hydraulic fluid to the rams 24 and 25 and for controlling operation of the motor 20 are provided on the platform 13.

There is mounted on the body 10 a pair of wheels 29 which project from the underside of the body. When the legs 11 are in their inoperative positions, the apparatus rests on the wheels 29 and can be wheeled along the ground by a user.

The body 10 is rectangular, as viewed in plan, the longer dimension of the body being that dimension which extends in a direction from the pump 28 to the mounting member 19. The width of the body, including the pivots 17 for the legs, is preferably not greater than 0.735 metre. A body of this width can pass through doorways commonly provided in dwellings. When the apparatus is to be moved from place to place, the length of the arm 12 is aligned with the longer dimension of the body 10. The platform 1 3 may have a dimension measured in the direction of the width of the body which does not exceed the width of the body.

Alternatively, the platform may be detachable from the arm and this dimension of the platform may exceed the width of the body. If required to facilitate movement of the apparatus from place to place, the arm 12 may be detachable from the mounting member 1 9.

The legs illustrated in Figures 1 and 2 are rectilinear. In the modification of the apparatus which is illustrated in Figure 3, the legs are nonrectilinear but other components of the apparatus may be the same as those of Figures 1 and 2. The legs 30 of Figure 3 each include a first part 32 which extends, in the operative position, outwardly and upwardly from the body of the apparatus and second and third parts 33, 34 which extend downwardly and outwardly. The second and third parts may be rectilinear and arranged to telescope one within the other. These parts may be arranged to pivot relative to the first part of each leg when the leg is moved to its inoperative position. The first part is also preferably mounted on the body for pivoting relative thereto. Means as hereinbefore described may be provided for releasably securing the legs in their operative positions.

With the legs illustrated in Figure 3, the wheels of the body may rest on the ground whilst the apparatus is in use. In a case where three or four legs as shown in Figure 3 are provided, the wheels of the body may lie inside a figure defined by the feet of the legs. Alternatively, two legs only may be provided, engagement of the feet of these legs and of the wheels with the ground being relied upon collectively to establish the required stability.

It will be noted that no means is provided for driving the wheels of the apparatus so that the weight of such driving means is avoided. The weight of the components of the apparatus may be as iow as is reasonably commensurate with the functions of those components, no component being deliberately made heavy, with a view to improving stability. Alternatively, relatively low density materials may be used for some components and higher density materials for other components, for example the limb 21 of the arm 12. Typically the legs would be formed of aluminium. At least the limb 22 of the arm and the platform also would be formed of aluminium. The limb 21 may be made of steel.

Pivoting of the limbs 21 and 22 of the arm may be restricted so that a predetermined part of the platform 1 3 is confined to a region lying between the axis of rotation of the mounting member 1 9 relative to the body 10 and a vertical piane which extends through selected feet of the apparatus when the legs are in their operative positions.

For use in the event of power failure, the apparatus may include a valve for controlling flow of hydraulic fluid from the ram 25 under the action of gravity on the platform 13 and on the upper limb 22 of the arm. Normally, this valve would remain closed. However, the valve could be opened a selected amount to permit a controlled contraction of the arm 25 and downward pivoting movement of the limb 22. Corresponding provision may be made for permitting contraction of the ram 24 in the event of power failure. Means may also be provided for permitting or causing rotation of the mounting member 1 9 relative to the body 10 in the event of power failure. This means and the valve or valves may be so positioned that they can be operated manually by a person standing on the ground, even when the platform 13 is raised far above the ground.

Alternatively or additionally, the valve or valves and said means may be arranged so that they can be operated by a person standing on the platform 13.

There may be associated with each foot 1 6 means responsive to a reduction in the downward load applied to the foot by the associated leg.

Such means may be adapted to provide an audible or visual warning when the downward load falls to zero orto a predetermined value. In a case where small movements of each foot relative to the associated leg can occur, this means may include a limit switch responsive to such movement.

It is intended that the motor 20 and the pump 28 would be supplied with power from an externai electrical circuit, for example electric mains. There is preferably provided on the body a socket into which a mains lead can be plugged or a connector for a mains lead. Lines for connecting the control means on the platform 13 with the motor 20 and pump 28 may include releasable coupiings disposed on or adjacent to the body 10.

Claims (1)

1. Apparatus comprising a body having a plurality of legs for engaging the ground, an arm mounted on the body for movement relative thereto and a platform carried on the arm, wherein the legs can be moved relative to the body between operative positions and inoperative positions.

2. Apparatus according to claim 1 wherein the configuration of the apparatus when the legs are in their respective operative positions and the platform is at the limit of its permitted lateral movement from the body, is such that no ballast is required during use of the machine.

3. Apparatus according to claim 1 or claim 2 wherein the body has a width less than 0.9 metre.

4. Apparatus according to claim 3 wherein the body has a length exceeding its width.

5. Apparatus according to any preceding claim wherein the arm is pivotable relative to the body about an axis which is generally horizontal in use.

6. Apparatus according to claim 5 wherein the arm comprises two relatively pivotable parts, one connected with the body and the other connected with the platform.

7. Apparatus according to any preceding claim wherein the legs are pivotable relative to the body about respective axes which are generally horizontal in use.

8. Apparatus according to claim 7 wherein each said leg comprises two relatively movable parts.

9. Apparatus according to claim 8 wherein said parts of each leg are relatively pivotable about an axis which is generally horizontal in use.

10. Any novel feature or novel combination of features disposed herein or in the accompanying drawings.

New claims or amendments to claims filed on 1 July 1983 Superseded claims Claim 1 New or amended claims:-- Claim 1

1. Apparatus comprising a body having a plurality of legs for engaging the ground, an arm mounted on the body for pivoting relative thereto about an axis which is upright in use and a platform carried on the arm, wherein the legs can be pivoted relative to the body upwardly and downwardly between operative positions and inoperative positions.