GB2357806A

GB2357806A - Load bearing props

Info

Publication number: GB2357806A
Application number: GB9928559A
Authority: GB
Inventors: Trevor John Honour
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-12-02
Filing date: 1999-12-02
Publication date: 2001-07-04
Also published as: GB9928559D0

Abstract

A load bearing prop 30 comprises telescopic support shafts 31-34 which are moved outwardly by means of a hydraulic mechanism operated by a pedal 36 and/or a handle 37. Hydraulic oil, which is held in a reservoir (70 or 71) at the base of the prop, is acted on by a piston 61 travelling in an internal canal of shaft 34. The prop is lowered by handle 41 which controls a ratchet mechanism 40.

Description

2357806 Load Bearing PrUs The present invention relates to props for use

in load-bearing applications, e.g. construction work. 5 Existing props, such as the standard acrow prop, are of the manually-operated screw lift type. Such props can be cumbersome and awkward to locate and elevate, and setting them to precisely the required height can be difficult and time-consuming.

The present invention seeks to overcome or reduce one or more of the above disadvantages.

According to a first aspect of the present invention there is provided a load-bearing prop comprising a plurality of mutually-telescoping support members and a hydraulic control 15 mechanism for controlling the relative telescopic movement of the support membrane.

According to a second aspect of the present invention there is provided a load-bearing prop comprising a plurality of mutually-telescoping support members and a releasable ratchet mechanism which is operable to control the relative telescopic movement of the 20 support members.

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows a prior art prop of the manual screw lift type;

Figure 2 shows a load-bearing prop in accordance with the present invention; Figure 3 shows a sectional view of part of the prop of Figure 2; and 30 Figures 4 and 5 show modifications of the part shown in Figure 3 2 Referring to the drawings, Figure 1 shows an acrow type prop 10 comprising two mutually-telescopic shaft members 11, 12. Shaft 11 retracts into shaft 12 for transport and storage purposes. To cover heights of approximately 1 to 6 metres, a range of six different models is required.

The exterior surface of the top part 22 of shaft 12 is threaded and has a vertically extending slot 20. The threaded part 22 is engaged by a rotatable internally threadec collar 14 having an attached operating lever 15. The bottom part of shaft 11 has a plurality of vertically-spaced holes 16. The top end of shaft 11 has a flat plate 17 wia sh wn central hole 27. For supporting formwork or shuttering, a forkhead member, not may be inserted in hole 27. The bottom of shaft 12 is provided with a footplate 28.

To raise the shaft 11 relative to shaft 12, a securing pin 18 is inserted through slot 22, into one of the holes 16. The collar 14 is then rotated around the shafts by direct manual operation of lever 15 and this pushes on the pin 18 to raise shaft 11. The shaft 11 ca be lowered by reversing this procedure.

Certain difficulties can arise when erecting such props. Often at least two attempts are required to place the prop in the required position due to the set holes 16 in the prop shaft 11 which only allow a set distance of elevation from the elongated slot in prop lhaft 12.

When one is working in tight areas with load bearing areas above that need to be restrained from giving way, existing props are time consuming in getting into positio in one easy operation.

Figure 2 shows a load-bearing prop 30 in accordance with the present invention. Prop 30 comprises a mutually-telescoping ram arrangement having steel shaft members 3 1 -34.

The shaft members are moved outwardly to raise the prop by means of a hydraulic 3 control system pumped by a foot pedal 36 or by a handle 37 with a grip 38. Highpressure oil seals 39 are provided at the junctions between the shaft members 31-34.

A ratchet mechanism 40 is provided between shafts 33 and 34 to prevent premature release and lowering of the prop 30. When lowering of the prop is required, a further handle 41 is actuated to release the ratchet mechanism in a slow and controlled manner.

A removable forkhead 50 is provided at the top of shaft 31, and a detachable guard member 51 is provided around the top of the ram arrangement to protect it from flying debris.

Further details of the hydraulic control system of prop 30 are shown in Figure 3, from which pedal 36 has been omitted for the purposes of clarity. A piston is 61 operated by a linkage mechanism connected to handle 37 (andlor pedal 36) via a swivel joint 62.

Piston 61 travels in a slave cylinder 63 to work the oil canal 64 of shaft member 34.

Succeeding shaft members 3, 32 have inner oil canals (not shown) of successively smaller size since less pressure is required.

The above-described prop has numerous advantages. Hydraulic oil has great strength.

In addition it does not evaporate. Both these factors contribute to only a small volume of hydraulic oil being required which leads to a prop of relatively light weight. In addition, since the hydraulic oil has a significant load-bearing capability, the steel of the shaft member may have a lighter weight than in the prior art arrangements. This improves mobility and eases location.

Since more shaft members are employed, a wider range of heights can be achieved by a single prop. Also, an essentially continuous range of heights can be achieved, which avoids the prior art problem of discrete settings. Indeed, the prior art setting pin is no longer needed since the hydraulic arrangement can support the load in use.

4 Correct positioning of the prop can be regularly achieved first time in normal use. tIhe grip 38 of handle 37 bein at waist height is convenient for raising the pro 9 P.

Various modifications may be made to the above-described arrangement. For example, the prop 30 may be provided with only pedal 36 or only handle 37. Although handles 37, 41 and guard member 51 are preferably detachable for storage and transport, th y may be fixedly attached to the prop if required; in this case handles 37, 41 are prefeably ' collapsible, e.g. telescopic or foldable.

Prop 30 may comprise two, three or more individual shaft members. Ratchet mechanisms 40 may be provided at all the junctions between the shaft members.

Alternatively, no ratchet mechanism need be provided, since the load can be borne by tho hydraulic arrangement. Some or all of the ratchet mechanisms may be replaced by a security pin (not shown) which passes through holes in the walls of adjacent shaft 1 members to prevent relative movement therebetween until removal of the pin.

The hydraulic oil for the system may be held in a reservoir 70 surrounding the base)f shaft 34 as shown in Figure 4. Alternatively a reservoir 71 may be provided at one side of the base as shown in Figure 5. (The pedal 36 has been omitted from Figures 4 ad 5 for the purpose of clarity). An electronic or motor-powered pump may be used to pressurise die hydraulic system if desired.

Claims

1. A load-bearing prop comprising a plurality of mutually telescoping support members and a hydraulic control mechanism for controlling the relative telescopic 5 movement of the support members.

2. A prop according to claim 1, Wherein a pedal is provided for telescoping the support members outwardly.

3. A prop according to claim 1 or 2, wherein a handle is provided for telescoping the support members outwardly.

4. A prop according to claim 2 or 3, wherein the support members are telescoped outwardly by a piston travelling within a shaft member inner hydraulic fluid canal.

5. A prop according to claim 4 wherein succeeding shaft members have inner hydraulic fluid canals of successively smaller size.

6. A prop according to any preceding claim, wherein a ratchet mechanism incorporating a release member is provided for retracting the prop in a controlled manner.

7. A prop according to any preceding claim, wherein the hydraulic fluid is held in a reservoir surrounding the base of the prop.

8. A prop according to any of claims 1 to 6, wherein the hydraulic fluid is held in a reservoir provided at one side of the base of the prop.

9. A load-bearing prop comprising a plurality of mutually-telescoping support members and a releasable ratchet mechanism which is operable to control the relative telescopic movement of the support members.

6

10. A load bearing prop substantially as herein described with reference to Figures and 3, whether or not modified in accordance with Figure 4 or 5, of the accompanying drawings.

1 i ' 1 P