GB2353272A

GB2353272A - Levelling Jacking apparatus

Info

Publication number: GB2353272A
Application number: GB0015255A
Authority: GB
Inventors: Derek William Rowswell
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-06-26
Filing date: 2000-06-23
Publication date: 2001-02-21
Also published as: GB9914930D0; GB0015255D0

Abstract

Jacking apparatus comprises a platform (3) raised by e.g. a pneumatic actuator 2 with a pair of support elements (4) each incorporating a stabilising hydraulic piston-and-cylinder assembly (5), and a regulator arrangement (6) with two regulator hydraulic piston-and-cylinder assemblies. The regulator hydraulic piston-and-cylinder assemblies are incapable of independent movement, and each regulator cylinder is fluidly connected to one of the stabilising cylinders. This compensating mechanism ensures that the platform remains level during upward or downward motion, even under an unevenly distributed load. Preferably, a scissors linkage is also provided between a base 1 and the platform 3. A number of arrangements of the linked regulator pistons are described with respect to Figs 4-6.

Description

2353272 Jackinq apparatus The present invention relates to jacking

apparatus, and in particular to apparatus with means for controlling the position, orientation and/or displacement of a platform or other load bearing element or assembly under load.

Conventionally, jacking apparatus has one or more load bearing elements, for example platforms or beams, which can be raised by mechanical means such as pneumatic or hydraulic rams. Jacking apparatus can easily be stabilised when stationary, but it is much more difficult to maintain lateral stability during motion, especially under an unevenly distributed load. If apparatus tilts during motion loads may become destabilised or the apparatus itself may be damaged. Thus, there is a need to provide jacking apparatus with stabilising means to keep a load bearing element level even under an unevenly distributed load. It is also desirable to be able to control the rate of ascent or descent of the load bearing element(s) and/or to be able to lock it in any position, e.g. to prevent accidental collapse and/or to reduce the effects of vibrations that may be generated by the lifting device, particularly if this is an air bellows actuator.

Accordingly the present invention provides jacking apparatus comprising:

a) a lifting device, b) load bearing means, carried by said lifting device, c) a pair of support elements supporting said load bearing means, each of said support elements comprising a stabilising hydraulic piston-and cylinder assembly, wherein vertical displacement of the platform requires movement of the stabilising pistons relative to their cylinders, d) a pair of regulator hydraulic piston-and-cylinder assemblies configured so that relative movement between the piston and cylinder of one regulator assembly requires corresponding relative movement of the second regulator assembly, each of said regulator hydraulic cylinders being in fluid communication with respective ones of said stabilising hydraulic cylinders.

Jacking apparatus according to the present invention may be mounted on any suitably stable floor or other support.

Alternatively, it may comprise an integral base, wherein the support elements act between the base and the load bearing means.

Load bearing means may comprise a platform, a beam, a frame comprising a plurality of beams or any load bearing means requiring lateral support according to the present invention The lifting device may comprise a pneumatic device, a hydraulic device or any. suitable lifting apparatus. In a preferred embodiment the lifting device is a pneumatic assembly such as an air bellows actuator. One or more lifting devices may be used either alone or in combination.

It is a feature of the present invention that the load bearing means need not be balanced with respect to the lifting device. The support elements may flank the lifting device or be located on the same side of the lifting device, as long as they are spaced sufficiently apart to provide suitable lateral support for the load bearing means.

More than one pair of support elements, with corresponding stabilising and regulator hydraulic assemblies may be used, for example, to stabilise a platform against tilting in different directions.

Support elements may include hinged support linkages, acting between base or ground and the load bearing means.

Such support linkages may provide additional lateral support to the load bearing means.

In a preferred embodiment the regulator piston-and cylinder assemblies are equal. Typically, the cylinder bores are equal. Other embodiments are possible, in which the regulator cylinders are not equal. In such a case, the stabilising cylinders will be correspondingly unequal in order that the hydraulic compensating mechanism remains functional.

The regulator piston-and-cylinder assemblies are configured in a regulator arrangement such that either is incapable of movement independent of the other. This may be achieved in a variety of ways. The cylinders may be formed from a single block or secured together in parallel. The pistons may be tied, for example by means of a common block, or manufactured in a single piece.

Alternatively, independent cylinder barrels may be separately anchored, and the pistons connected together to ensure similar movement. Such an arrangement may be reversed, so that the pistons are separately anchored and the cylinder barrels linked together.

Thus, in jacking apparatus according to the present invention neither stabilising hydraulic assembly can move without an equal movement of the other, and so the load bearing means will remain level regardless of the distribution of load. Pressure applied to one end of the load bearing means (for example because of an unequal loading) is transmitted to the other end through the combination of stabilising and regulator hydraulic assemblies.

Vertical movement of the load bearing means, upwardly or downwardly, requires movement of one of the stabilising pistons relative to its cylinder. The f luid communication between the stabilising and regulator cylinders, combined with the dependence of the regulator cylinders on one another, results in a corresponding movement of both regulator assemblies, and consequently a movement of the second stabilising assembly identical to that of the first. Thus any movement of one end of the load bearing means is accompanied by an equal movement of the other end. Consequently the load bearing means remains level as a result of compensation provided by the hydraulic stabilising system.

The apparatus may further comprise locking means to immobilise the platform at a desired height. Such locking means may lock the position of the support elements. In a preferred embodiment the locking means act by locking the position of the regulator piston-and cylinder assemblies. Locking may be achieved mechanically, for example by clamping a movable portion of the regulator arrangement in place, so as to prevent movement of the regulator pistons relative to their cylinders, or by any other suitable means. The locking mechanism may be actuated manually, remotely, or electronically. In one embodiment, the locking mechanism is actuated manually via a clamping handle. The clamping handle will typically engage with a movable portion of the regulator arrangement and a fixed element, such as a mounting panel, which may be secured to a base of the apparatus.

The locking mechanism may allow the load bearing element to be fixed in a raised position without continued input from the lifting device. Additionally or alternatively it may prevent accidental collapse, or may for example reduce vibration transmitted to a platform from a lifting device such as an air bellows under load.

The rate of ascent or descent of the platform may be controlled by means of the lifting device.

Alternatively, the rate of ascent or descent of the platform may be controlled by means of the hydraulic fluid movement between stabilising and regulator cylinders. For example, the bore of the tubing used to connect stabilising and regulator cylinders may be chosen so as to limit the rate of fluid flow therein and thus restrict the maximum rate of movement of the platform.

Specific embodiments of the present invention will now be described in detail by way of example, by reference to the accompanying figures., in which Figure 1 shows front and side elevations of jacking apparatus according to the present invention Figure 2 shows front and side elevations of an alternative embodiment with a different configuration of support elements Figure 3 shows front and side elevations of an alternative embodiment with a different configuration of support elements Figure 4 shows detail of a paired regulator piston-and cylinder arrangement Figure 5 shows an alternative regulator arrangement Figure 6 shows a further possible regulator arrangement As shown in Figure 1, a rectangular base 1 is constructed from side girders 12 with upper and lower base plates 14 and 16 respectively. Mounted in the centre of the base 1 is an air bellows actuator 2, connected to a compressed air supply (not shown), which carries a platform 3 of approximately the same dimensions as base 1. The platform is supported at each end by hinged support linkages 4, which are pivotally connected to brackets 32 on the underside of the platform 3, and to bars 18 cross bracing the ends of girders 12, within the frame of the base.

Hydraulic stabiliser piston-and-cylinder assemblies 5 are pivotally connected to the middle hinges 42 of the support linkages 4, and to brackets 34 on the underside of the platform 3. Any vertical displacement of the platform therefore requires a movement of the piston 52 relative to its cylinder 54. Alternative configurations of the stabiliser assemblies 5 are illustrated in Figures 2 and 3. In Figure 2, the stabiliser assemblies 5 extend between the base 1 and hinge 42 of the support linkage 4.

In Figure 3 they extend directly between the base and platform.

A regulator arrangement 6 mounted adjacent the base 1 consists of a fixed cylinder block 61 with two cylinders 62 housing respective pistons 63, as shown in Figure 4.

Pistons 63 are fast with a piston block 64 which is free to move slidingly as pistons 63 move relative to their.

cylinders 62. A clamping handle 65 extends through a slot 66 in a mounting plate 67 into a threaded hole 68 in piston block 64.

Regulator cylinders 62 are connected to respective stabilising cylinders 54 by hydraulic tubing 7.

Consequently movement of a stabilising piston 52 relative to its cylinder 54 causes corresponding movement of the respective regulator piston 63 relative to its cylinder 62. Because the regulator pistons are tied, this movement induces a similar movement of the opposite stabilising piston-and-cylinder assembly. Thus when one side of the platform is pressed downwards, the combined action of the stabilising and regulator assemblies draws the other side of the platform downwards by the same amount, maintaining the level of the platform and preventing tilting.

The regulator piston block 64 can be locked in position by screwing clamping handle 65 into hole 68 so that handle 65 engages frictionally with mounting plate 67.

This locking mechanism guards against collapse or unwanted vibration etc. of the platform.

Alternative regulator arrangements are illustrated in Figures 5 and 6. Where possible the same reference numerals are used as in previous diagrams. In Figure 5, separate regulator cylinder barrels 60 are pivotally connected to brackets 11 on the base 1, and the rods of the regulator pistons 63 are connected together at their top ends by means of the clamping handle 65, which extend through a vertical slot 66 in mounting panel 67.

Clamping handle 65 may be tightened to engage frictionally with the mounting panel 67 in order to lock the position of pistons 63. Alternatively the pistons may be tied by means of a block mounted in a vertical slot behind mounting panel 67. This regulator mechanism arrangement may be reversed, so that the cylinder barrels are tied, while the piston rods are pivotally connected to the base.

In the regulator arrangement shown in Figure 6, the regulator cylinder barrels 60 are opposed. The ends of pistons 63 are pivotally connected to the circumference of a disc 8, which is free to rotate about its centre.

Clamping handle 65 extends through a curved slot 66 in disc 8, into a threaded hole in a mounting block 9.

Screwing the clamping handle 65 into the mounting block 9 causes frictional engagement of clamping handle 65 with the disc 9, locking the regulator arrangement.

In all the above-described embodiments, a hydraulic fluid surplus is provided in the regulator cylinders, in order to compensate for hydraulic fluid loss over time by wetting of cylinder bores.

Claims

CLAIMS:

1. Jacking apparatus comprising:

2. Jacking apparatus according to claim 1, wherein the support elements flank the lifting device.

3. Jacking apparatus according to claim 1 or claim 2, wherein the regulator pistons are tied.

4. Jacking apparatus according to claim 3, wherein the regulator pistons are fast with a common block, or secured together in parallel.

5. Jacking apparatus according to claim 3 or claim 4, wherein the regulator cylinders are formed in a common block.

6. Jacking apparatus according to any one of the preceding claims, further comprising locking means for locking the load bearing means at a required height.

7. Jacking apparatus according to claim 7, wherein the locking means acts by locking the position of the regulator piston-and- cylinder assemblies.

8. Jacking apparatus according to claim 7 or claim 8, wherein the locking means are actuated by a clamping handle.

9. Jacking apparatus according to any one of the preceding claims, further comprising a base, wherein the support elements act between the base and the load bearing means.

10. Jacking apparatus according to any one of the preceding claims, wherein the support elements further comprise hinged support linkages.

11. Jacking apparatus according to any one of the preceding claims, wherein the lifting device comprises an air bellows actuator.

12. Jacking apparatus according to any one of the preceding claims, wherein the load bearing means comprise a platform.

13. Jacking apparatus substantially as herein described, with reference to the accompanying figures.