GB2370560A - Lifting device - Google Patents

Abstract

Lifter 1 has a lifting beam 2 near to each end of which is secured an arm 4 by clamp 3 holding wheel 5. Lifter 1 has a hook (10 Figs 1 and 2) to hold an manhole cover. Manual operation of piston 9 cases lifter 1 to move between positions thereby raising beam 2 and hence any attached manhole cover to a maximum of about 0.34 metres from the ground. The pump is carried by a frame 8 to which it is pivotally connected at one end and to a sleeve 6 carried on the beam 2 at the other end. The frame is also pivotally connected at spaced locations to the sleeve 6 and is supported on a further wheel. The arrangement allows picking up manhole covers from below ground level and is easily dismountable to allow carrying in a small van.

Description

LIFTING DEVICE

The present invention relates to a lifting device. British Patent Specification No. 1268352 describes a lifting device for the lifting of manhole covers. It utilises a hydraulic pump piston on a framework which operates between a first position in which the hooks engage a manhole cover and a second raised position in which the manhole cover is held above the ground such that the lifting device can be moved on wheels allowing access to the manhole.

While the lifting device illustrated in GB 1268352 has been adequate in the past, it is not able to lift heavier manhole covers. Also the distance by which the manhole cover is raised above the ground is very restricted. The is problematic in operation and may jam or halt completely. Also the lifting device is not capable of lifting manhole covers which are below ground level. Furthermore, the lifting device is large and cumbersome, and cannot be disassembled or readily transported.

There have been other designs of manhole cover lifters, but again they have been very limited in their lifting capabilities. Furthermore, they have not been easily transported, for example in a standard small van. Also, they have had very limited capability of lifting manhole covers sunk below ground level.

According to the present invention, there is provided a lifting device comprising a lifting beam, means to attach an article for lifting to the beam, a frame formed of two members pivotably engaging the lifting beam at spaced positions along the length of the beam, the members connecting adjacent the opposite end of the frame with pump piston means, another end

of the pump piston means also connecting pivotably with the same face of the beam intermediate the pivot points with the two members wherein, in a first position of the pump piston means the attachment means is located for attachment to an article, and in a second position the attachment means is remote from the attachment position.

Preferably, in the first mode, the attachment means is at or adjacent ground level; also, in the second mode, the attachment means is at a position raised from ground level.

Preferably, the lifting device comprises a V-shaped frame formed of two members.

Preferably, the frame is slidable and selectively clampable along the length of the beam. The frame may be detachable from the beam.

Preferably, at least one wheel is located on the beam, e. g. two wheels are detachably located adjacent opposite ends of the beam and a wheel is located at the end of the frame remote from the beam.

The pump piston means may comprise a manually operable hydraulic or pneumatic piston.

The lifting device may comprise a frame, and two wheel units detachably mounted of the lifting beam and includes a kit of parts comprising a lifting beam, a frame and two wheel units.

The lifting device embodying the present invention provides a very compact arrangement when assembled and in both extreme positions during operation, also when disassembled ready for transportation.

The lifting device embodying the present invention provides an enhanced height of lifting as compared to the prior art lifters. Also the lifting device embodying the present invention enables the lifting of manhole covers which are located below ground level, up to 0.02 metres below ground level, which is not possible using prior art lifters.

In order that the invention may more readily be understood, a description is now given, by way of example only, reference being made to the accompanying drawings, in which: Figure 1 is a side view of a lifter of the present invention in one position; Figure 2 is a side view of the lifter of Figure 1 in another position; Figure 3 is a plan view of the lifter of Figure 1; and Figures 4A and B are views of the pivot points of the lifter of the present invention and of a prior art lifter.

Lifter 1 has a lifting beam 2 of length 1.22 metres and of hollow, square (0.04 metres) cross-section. Near to each end of beam 1 there is detachably secured, by means of clamp 3, an arm 4 of length 0.095 metres holding a wheel 5 of radius 0.125 metres.

At the central portion of beam 2, there is located a sleeve 6 of length 0.16 metres which has two pivot points 7 spaced 0.12 metres apart to connect with V-frame 8 supporting a hydraulic piston 9.

Lifter 1 has a hook 10 to hold a manhole cover. Hook may be located on sleeve 6, or it may be located as a separate element on beam 2 whether permanently fixed thereon or detachable with a clamp.

Manual operation of piston 9 causes the lifter 1 to move between the position in Figure I in which hook 10 is located to engage with a rung on a manhole cover, to the position in Figure 2 thereby raising beam 2 (hence hook 10 and any manhole cover attached to hook 10) to a maximum lifting stroke of approximately 0.34 metres from the ground. This will result in a sufficient clearance between the base of the manhole cover and the ground to allow the manhole cover to be moved away from the manhole and then lowered to the floor (this being necessary for safety reasons). The movement is achieved by operating pump 9 which extends ram 11 to move pivot point x (see Figure 4A) thus rotating sleeve 6 and beam 2 about point y which pulls wheels 5 toward the pump 9 lifting the main body and hook 10 raising the cover. Piston 9 operates to produce an extension of ram 11 by 0.08 metres, applying a force of approximately 120 Newtons enabling a mass of up to 900 Kg to be raised to a maximum height of 0.34 metres above ground level.

By means of various elements of the present invention, lifter 1 enables pick up of covers which are up to 0.03 metres below ground level. For example, the arrangement of a frame with two members especially in the illustrated form of a V-shape provides effective pick-up of sunken manhole covers from a considerable depth, greater than in prior art lifters. Also the positioning of pivoting connections on the same face of the beam with the pump piston means and the members enhances this feature.

Figure 4A shows in detail the pivot points in lifter 1, whereby beam 2 and frame 8 have a pivot point at pin y located at distance d, (typically 2.5 xi0-2 metres) from the perimeter of beam 2 while pivot point x is located at d2 (typically 2. 0xi0-3 metres) above the same side of beam 2, and at d3 (typically 3. 5xl 0-3 metres).

The V frame of the present invention also allows the piston 9 and/or its ram 11 to drop in the gap between the individual members of V frame 8 thus allowing the unit to travel lower and higher.

Figure 4B shows the corresponding pivot positions of the lifter of British Patent Specification No. 1268352. These characterisics enable an increased height of lift of ground clearance to be achieved, and ensures a lower drop of hook 10 for the pick-up of sunken covers as compared to all prior art lifters.

Lifter 1 can be readily and simply disassembled so that it can be transported in a standard van. Thus clamps 3 are loosened to enable arm 4 and wheels 3 to be slid off beam 2, likewise hooks 10 and sleeve 6 (whether hook (s) and sleeve are separate elements or integrated). If appropriate, wheel 11 can also be detached from frame 8. Thus all the component parts of the lifter 1 can be packed away into a very small volume, easily contained in a standard van luggage compartment.

Claims (15)

1. A lifting device comprising a lifting beam, means to attach an article for lifting to the beam, a frame formed of two members pivotably engaging the lifting beam at spaced positions along the length of the beam, the members connecting adjacent the opposite end of the frame with pump piston means, another end of the pump piston means also connecting pivotably with the same face of the beam intermediate the pivot points with the two members wherein, in a first position of the pump piston means the attachment means is located for attachment to an article, and in a second position the attachment means is remote from the attachment position.

2. A lifting device according to Claim 1 wherein, in the first pump piston means position, the attachment means is at or adjacent ground level.

3. A lifting device according to Claim 2 wherein, the first pump piston means position, the attachment means is below ground level.

4. A lifting device according to any preceding claim wherein, in the second pump piston means position, the attachment means is at a location raised from ground level.

5. A lifting device according to any preceding claim comprising a Vshaped frame formed of two members.

6. A lifting device according to any preceding claim wherein the frame is slidable and selectively clampable along the length of the beam.

7. A lifting device according to any preceding claim wherein the frame is detachable from the beam.

8. A lifting device according to any preceding claim comprising at least one wheel located on the beam.

9. A lifting device according to any preceding claim comprising two wheels detachably located adjacent opposite ends of the beam.

10. A lifting device according to any preceding claim comprising a wheel located at the end of the frame remote from the beam.

11. A lifting device according to any preceding claim wherein the pump piston means comprises a manually operable hydraulic or pneumatic piston.

12. A lifting device according to any preceding claim comprising a frame, and two wheel units detachably mounted on the lifting beam.

13. A lifting beam according to Claim 12 comprising a wheel unit detachably mounted on the frame.

14. A lifting device substantially as hereinbefore described with reference to, and/or as illustrated in, any one or more of the accompanying drawings.

15. A kit of parts according to any preceding claim comprising a lifting beam, a frame and two wheel units.