GB2219273A

GB2219273A - Powered access platform units

Info

Publication number: GB2219273A
Application number: GB8811112A
Authority: GB
Inventors: Mark Richardson
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-05-11
Filing date: 1988-05-11
Publication date: 1989-12-06
Anticipated expiration: 2008-05-11
Also published as: GB8811112D0; GB2219273B

Abstract

A powered access platform unit having an elevating structure (24, 26, 28, 30) which supports the platform (14) at both sides thereof, the arrangement being such that, in the fully lowered position, the platform (14), including its skeleton side wall (16), is accommodated over the base (10) wholly within the collapsed elevating structure. <IMAGE>

Description

Improvements in Powered Access Platform Units This invention relates to a platform having a powered drive for lifting equipment and personnel from a first level to a higher level in order to give working access to an elevated part of a building or other structure. Such a platform is referred to herein as a powered access platform unit.

A powered access platform unit comprises a base, an elevating structure generally of the parallel-link type, scissors type or telescopic type, a platform mounted on the elevating structure, and a power unit for raising or lowering the platform via the elevating structure. The base is usually in the form of a trolley, and may be self-propelled from the same drive unit, or may be in the form of a trailer which can be moved by a towing vehicle. Whatever the type of elevating structure, assuming the platform is lowered into its first level directly above the base, this first level is usually determined by the height of the retracted or collapsed elevating structure. This first level is therefore typically of the order of two metres high above the ground, and for this reason the base usually incorporates a fixed ladder which has to be ascended in order to reach the platform.

This can be highly disadvantageous, especially when loading the platform with equipment.

It is an object of this invention to provide a powered access platform unit which at least minimises the above-described disadvantage: According to the invention, there is provided a powered access platform unit having an elevating structure which supports the platform at opposite sides of said platform, the arrangement being such that, when the platform is lowered to its minimum, it is accommodated over the base within the retracted or collapsed elevating structure.

The invention is thus able to provide a powered access platform unit in which the platform, in its minimum level position, lies substantially below the level of the top of the retracted or collapsed elevating structure. Even when, as is usual, the platform is provided with safety skeleton walls, it is possible for the top of said walls to lie at least no higher than the level of the top of the retracted or collapsed elevating structure, when the platform is in its minimum level position.

The invention is especially but not exclusively applicable to a powered access platform unit having an elevating structure of the parallel link type. This parallel link elevating structure may take the form of a folding boom system consisting of two similar and tied together booms which support the platform between them, and within which the platform is received in the collapsed condition.

The folding boom system is preferably mounted at one end at or adjacent the tops of two corner pillars at one end of the base and at the other end the system is mounted to the platform at or adjacent two corners at opposite sides thereof. In the collapsed condition of the folding boom system, the two spaced pairs of parallel links connecting to the base extend obliquely downwardly from the respective pillars towards the opposite end of the base, where two spaced intermediate boom links are upstanding (and maintain their vertical orientation during elevation), and two boom links connecting with the platform extend obliquely downward from the tops of said intermediate links towards the first end of the base, i.e. generally towards the bottoms of the aforementioned pillars.The boom links connecting with the platform may be spaced parallel links, in themselves sufficient to maintain the platform in a horizontal orientation during elevation, or may be spaced single links associated with an auxiliary elevating ram also serving to maintain the horizontal orientation of the platform. A main elevating ram may then act between the base and the pair of parallel boom links connecting to said base.

Alternatively, a single elevating ram may act between the pair of parallel boom links connecting to the base and a pair of parallel boom links connecting to the platform.

Preferably, the intermediate boom links are tied together, whilst at the other end of the base, again referring to the folding boom system in its collapsed condition, the two sides of the boom system are not tied together, so that the platform can be entered between the above-mentioned base pillars and through a gate in the end wall of the platform skeleton wall structure.

The invention is able to provide a powered access platform unit wherein, in its minimum level position, the platform is less than one half a metre above ground level, so that a ladder on the base is not required, and equipment, in particular, is more readily loaded on to the platform.

The power drive is preferably hydraulic, sourced from a rechargeable power pck, the power unit being carried by the base. The base is preferably a trolley self-propelled by the same power unit. Control means is preferably provided on the platform so that the trolley can be operated, including propulsion and steering functions, by an operator on the platform, whether the platform is lowered or elevated.

A powered access platform unit in accordance with the invention is exemplified in the following description, making reference to the accompanying drawing, in which: Figure 1 shows the access platform unit in side view, in its minimum level condition; and Figure 1A shows the platform when elevated from the trolley base of Figure 1.

Referring to the drawings, the illustrated powered access platform unit comprises a base in the form of a trolley 10, a parallel link type elevating structure in the form of a folding boom unit generally referenced 12, and a platform 14 having a skeleton wall 16. The skeleton wall 16 has a gate (not visible) at the end of the platform indicated by the reference 18.

The folding boom unit 12 comprises a pair of similar booms, of which only the near one is visible in the drawing, each said boom connecting between the top of a corner pillar 20 on the trolley 10 and the bottom of a post 22 at the corresponding side corner of the platform 14.

The boom structure has spaced pairs of parallel links 24, 26 connecting with the tops of the corner pillars 20, spaced intermediate links 28 which are maintained in a vertical orientation during elevation, and spaced links 30 connecting with the platform. The intermediate links 28 are tied together by cross-members (not visible).

A main hydraulic ram 32 and an auxiliary hydraulic ram 34, powered from a rechargeable power pack and an hydraulic pump (not shown), serve to raise and lower the platform 14 via the folding boom unit 12. The ram 34 also serves to maintain a horizontal attitude of the platform 14 during elevation. However, it is possible to provide a second set of parallel links in the form of spaced pairs of parallel links connecting with the platform 14 to maintain the horizontal attitude of the latter, enabling hydraulic drive by means of a push-and-pull ram acting between the two sets of parallel links.

In accordance with the invention, when the platform is lowered to its minimum level position, say less than one half a metre above ground level, it is received wholly within the collapsed folding boom unit, as shown in Figure 1. The top of the skeleton wall 16 is below the tops of the corner pillars 20 on the base, so that the total height of the retracted structure is less than that normally achievable in a powered access platform. However, it is the very low level of the platform 14 itself which is particularly advantageous, because equipment to be used when the platform is elevated can be readily loaded on to the platform without use of a ladder, which necessarily is provided as part of the base structure in conventional access platforms. Entry on to the platform is via the end gate, which is freely reached by passage between the end pillars 20 on the base.

The preferred access platform unit is self-propelled from the same power pack, and controllable from the platform.

The illustrated access platform may be modified in various ways within the scope of the invention, which is also applicable to elevating structures in the form of twin scissors or twin telescoping structures, one on each side of the unit, and within which, when said elevating structure is collapsed or retracted, the platform is received down to a level close to ground level.

Claims

Patent Application No. 8811112.5

Claims 1. A powered access platform unit having an elevating structure which supports the platform at opposite sides of said platform, the arrangement being such that, when the platform is lowered to its minimum, it is accommodated over the base within the retracted or collapsed elevating structure.
2. A platform unit according to claim 1, wherein the platform is provided with safety skeleton walls, and the top of said walls lies at least no higher than the level of the top of the retracted or collapsed elevating structure, when the platform is in its minimum level position.
3. A platform unit according to claim 1 or claim 2, having an elevating structure of the parallel link type.
4. A platform unit according to claim 3, wherein the parallel link elevating structure comprises a folding boom system consisting of two similar and tied together booms which support the platform between them, and within which the platform is received in the collapsed condition.
5. A platform unit according to claim 4, wherein the folding boom system is mounted at one end at or adjacent the tops of two corner pillars at one end of the base and at the other end the system is mounted to the platform at or adjacent two corners at opposite sides thereof.
6. A platform unit according to claim 5, wherein, in the collapsed condition of the folding boom system, the two spaced pairs of parallel links connecting to the base extend obliquely downwardly from the respective pillars towards the opposite end of the base, where two spaced intermediate boom links are upstanding (and maintain their vertical orientation during elevation), and two boom links connecting with the platform extend obliquely downward from the tops of said intermediate links towards the first end of the base, i.e. generally towards the bottoms of the pillars.
7. A platform unit according to claim 6, wherein the boom links connecting with the platform are spaced parallel links, in themselves sufficient to maintain the platform in a horizontal orientation during elevation.
8. A platform unit according to claim 6, wherein the boom links connecting with the platform are spaced single links associated with an auxiliary elevating ram also serving to maintain the horizontal orientation of the platform.
9. A platform unit according to claim 7 or claim 8, wherein a main elevating ram acts between the base and the pair r of parallel boom links connecting to the base.
10. A platform unit according to claim 7 or claim 8, wherein a single elevating ram acts between the pair of parallel boom links connecting to the base and a pair of parallel boom links connecting to the platform.
11. A platform unit according'to any of claims 6 to 10, wherein the intermediate boom links are tied together, whilst at the other end of the base, referring to the folding boom system in its collapsed condition, the two sides of the boom system are not tied together, so that the platform can be entered between the above-mentioned base pillars and through a gate in the end wall of a platform skeleton wall structure.
12. A platform unit according to any of claims 1 to 11, wherein, in its minimum level position, the platform is less than one half a metre above ground level.
13. A platform unit according to any of claims 1 to 11, including a hydraulic power drive sourced from a rechargeable power pack, the power drive being carried by the base.
14. A platform unit according to any of claims 1 to 13, wherein the base is a trolley self-propelled by a power unit.
15. A platform unit according to claim 13 or claim 14, having control means on the platform so that the trolley can be operated by an operator on the platform, whether the platform is lowered or elevated.
16. A powered access platform unit substantially as hereinbefore described with reference to the accompanying drawings.