GB2241690A

GB2241690A - Platform scissor lift

Info

Publication number: GB2241690A
Application number: GB9002212A
Authority: GB
Inventors: G H Williams; W J Howgego
Original assignee: HANDLING CONSULTANTS Ltd
Current assignee: HANDLING CONSULTANTS Ltd
Priority date: 1990-02-01
Filing date: 1990-02-01
Publication date: 1991-09-11
Also published as: GB9002212D0

Abstract

In a platform scissor lift having a minimum vertical height when it is in the fully lowered position, respective pairs of arms 7 and 8 are cranked near their ends and pivotted so that when the scissor mechanism 2 is closed, the arms, apart from their cranked ends, lie parallel to one another and the bracing members 18, 19 and 20 are accommodated, thus minimising the overall height when fully lowered. There may be load bearing surfaces (21, 23. Fig 3) at different levels supported directly over the scissor arms 7, 8 with a lower surface (22) therebetween so that the load bearing surfaces are at a convenient working height for a man standing on the lower surface. The scissor lift platform may also be provided with wheels 11 so that it can travel and may be made to be self propelled. <IMAGE>

Description

Scissor Lift Platform This invention relates to a scissor lift platform.

Scissor lift platforms are well known devices comprising a platform which can be caused to rise or fall whilst being supported by a scissor mechanism. A feature of existing scissor lift platforms is that the members supporting the platform are substantially straight and the platform surface is usually of planar construction.

A disadvantage of existing types of scissor lift platform is that when fully lowered they are still of significant vertical extent. As it is often desirable for the working level of the platform to be at or near ground level when the platform is fully lowered, pits in the floor may have to be provided which are expensive to construct or valuable working height is lost.

According to the present invention there is provided a scissor lift platform comprising a base, a platform, a scissor mechanism and means to cause said platform to rise and fall, said scissor mechanism having pairs of arms lying in a vertical plane which are cranked near their ends and are pivotally connected near their centre points, corresponding arms of adjacent pairs of said arms being connected by horizontal bracing members over the major part of their length, said scissor mechanism being anchored to said base and cooperating with said platform so that when the platform is in the fully lowered position, the said arms lie parallel to one another over the major part of their length whilst accommodating the said bracing members.

In a preferred arrangement, the platform has a number of horizontal surfaces at varying levels. Preferably there will be load bearing surfaces supported directly over the scissor mechanism arms and a surface between these which is at a lower level such that sa id load bearing surfaces are at a convenient working height for a man standing on the lower surface. There may be further surfaces connecting with said lower surface which are at a still lower level.

In a version of the preferred arrangement the base of the scissor lift platform is equipped with wheels which enable the scissor lift platform to travel. One or more of these wheels may be driven.

A specific embodiment of a scissor lift platform, according to the invention, will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a side elevation of the scissor lift platform in a raised position.

Figure 2 is a side elevation of the scissor lift platform in the fully lowered position.

Figure 3 is a view on section line A-A of the scissor lift platform in the fully lowered position.

Referring to figure 1, the scissor lift platform comprises a platform 1, a scissor mechanism 2 and base 3. The scissor mechanism is acted upon by hydraulic rams 4, only one of which is shown. The rams are actuated by pressurised hydraulic fluid which is provided, via pipework, by a hydraulic power pack which is mounted on base 3 and comprises a pump/motor unit 5 and an oil reservoir 6.

The scissor mechanism comprises arms 7 and 8. Considering one pair of arms 7 and 8, one arm 8 comprises twin members which embrace one arm 7. The twin members of arm 8 are horizontally connected by members 19. This embodiment of the invention employs two pairs of arms 7 and 8, corresponding arms 7 being connected by bracing members 18 and corresponding inboard members of arms 8 being connected by bracing members 20.

The arms 7 and 8 of scissor mechanism 2 are pivotally connected to each other at points X, to the platform at points Y and the base at points Z. Arms 7 and 8 have rollers 9 which run on tracks 10. When rams 4 are actuated, arms 7 and 8 rotate relative to one another so that platform 1 moves vertically with respect to base 3. When pressure is applied, the platform rises, when it is released the platform falls. If desired, it is possible to apply pressure so that the platform is driven downwards.

This example of the invention is adapted to be self propelled and run on rails. Wheels 11 run on rails (not shown) so that there is a minimum working clearance between base members 12 and the ground. Two of the wheels 11 are connected by drive shaft 13 so that both rotate when the shaft is driven by geared motor unit 14. The wheels may be driven in either direction to give forward or reverse directions of travel. The motor gear unit 14 incorporates a brake which can be caused to act to arrest the platform. The base 3 incorporates buffers 15 which impinge on limit stops (not shown) at the ends of the rails.

Electrical power for the motor gear unit 14 and the pump/motor unit 5 is supplied via pick-up arm 16 which incorporates conducting means which co-operate with a bus-bar system (not shown). The operation of the platform is controlled from a push-button station (not shown) which may be mounted on the platform but could be in any convenient position.

There may also be additional push-button stations. A control panel 17 contains the necessary electrical equipment to effect the desired control functions.

Figure 2 shows the platform in the fully lowered position.

In this position, members 7 and 8 shown by dotted lines, are parallel with each other over the major part of their length, thus minimising the lowered height of platform 1.

At the ends of the platform there are low level surfaces 22a which are at a lower level than walkway 22.

Referring to figure 3, the positions of bracing members 18, 19 and 20 are shown when the platform is in the fully lowered position. Surfaces 21 and 23 are load bearing surfaces supported directly by scissor mechanism arms 7 and 8. Surface 22 is a pedestrian walkway at a lower level than surfaces 21 and 23 such that it is clear of cross members 20 and is at a level such that surfaces 21 and 23 are at a convenient working height for a man standing on surface 22. Surface 21 is shown to comprise conveyor rollers and surface 23 is made up of load bearing platework. Other types of surface are possible.

Claims

1. A scissor lift platform comprising a base, a platform, 9 scissor mechanism and means to cause said platform to rise and fall, said scissor mechanism having pairs of arms lying in a vertical plane which are cranked near their ends and are pivotally connected near their centre points, corresponding arms of adjacent pairs of said arms being connected by horizontal bracing members over the major part of their length, said scissor mechanism being anchored to said base and cooperating with said platform so that when the platform is in the fully lowered position, the said arms lie parallel to one another over the major part of their length whilst accommodating the said bracing members.

2. A scissor lift platform as claimed in claim 1 wherein the platform has a number of horizontal surfaces at varying levels.

3. A scissor lift platform as claimed in claim 2 wherein the platform has one or more load bearing surfaces which are supported directly over the scissor mechanism arms.

4. A scissor lift platform as claimed in claim 3 wherein the platform has one or more surfaces at lower levels than the load bearing surfaces, such that the load bearing surfaces are at a convenient working height for a man standing on at least one of said lower surfaces.

5. A scissor lift platform according to any preceding claim wherein the base is provided with wheels which enable the scissor lift platform to travel.

6. A scissor lift platform as claimed in claim 6 wherein one or more of the wheels is driven.

7. A scissor lift platform substantially as described herein with reference to Figures 1 - 3 of the accompanying drawings.