GB2126190A

GB2126190A - A jacking device

Info

Publication number: GB2126190A
Application number: GB08321973A
Authority: GB
Inventors: Anthony Lewis Reddaway
Original assignee: WESTPILE INTERNATIONAL UK LIMI
Current assignee: WESTPILE INTERNATIONAL UK LIMI
Priority date: 1982-09-02
Filing date: 1983-08-16
Publication date: 1984-03-21
Also published as: GB2126190B; GB8321973D0

Abstract

The jacking device comprises two blocks (10, 11) arranged one above another and a wedge (12) interposed between the blocks. The major outer surfaces (16, 17) of the two blocks are parallel to one another and at least one and preferably both of the facing inner surfaces (13, 14) of the blocks are inclined with respect to said major outer surfaces. The wedge has two converging surfaces which lie parallel to and make sliding contact with the facing inner surfaces respectively of the two blocks. Side flanges on the blocks maintain alignment between the wedge and the blocks in a direction of movement of the wedge. A threaded drawbolt (22) for moving the wedge has a head (22) at one end. The drawbolt extends into a hole (19, 20) in the wedge from the thin end thereof and engages with a thread in the hole (19) or with a threaded nut (29). A washer (25) between the head of the drawbolt and an end surface of each of the two blocks maintains alignment between the two blocks in the direction of movement of the wedge. <IMAGE>

Description

SPECIFICATION A jacking device This invention relates to a jacking device, particularly, for jacking up columns such as columns which are to support buildings or other similar structures, but also for other purposes such as to level turbines in electrical generating stations, for jacking up floors in buildings so that remedial work can be carried out on load bearing walls made of sub-standard concrete, for levelling railways and for use in mines.

many buildings are supported on concrete columns. There have been instances where these concrete columns have begun to deteriorate. In order to save the building, steel columns are erected to take the load off the concrete columns.

In one aspect the invention provides a jacking device comprising at least two blocks arranged one above another and a wedge interposed between two adjacent blocks, the upper surface of the uppermost block and the lower surface of the lowermost block being in parallel spaced relationship, at least one of the facing inner surfaces of adjacent blocks being inclined with respect to the upper surface of the uppermost block and the lower surface of the lowermost block, the wedge having two converging surfaces which lie parallel to and make sliding contact with the facing inner surfaces respectively of the two adjacent blocks, means for maintaining alignment between the wedge and the blocks in a direction normal to the direction of movement of the wedge relative to the blocks and parallel to the upper surface of the uppermost block and the lower surface of the lowermost block, a threaded drawbolt with a head at one end for moving the wedge along the facing inner surfaces of the two adjacent blocks to increase the separation between the upper surface of the uppermost block and the lower surface of the lowermost block, the drawbolt extending into a hole in the wedge from the thin end of the wedge and engaging with a thread in the hole or with a threaded nut, and a washer between the head of the drawbolt and an end surface of each of the two adjacent blocks to maintain alignment between the two adjacent blocks in the direction of movement of the wedge.

The alignment maintaining means, conveniently, comprise side flanges on each of the two blocks.

Advantageously, the facing inner surfaces of the two blocks are symmetrically inclined with respect to a plane parallel to the upper surface of the uppermost block and the lower surface of the lower most block.

Conveniently, grease nipples are provided in the thick end of the or each wedge with passages leading to the surfaces of the or each wedge in contact with the facing inner surfaces of the two adjacent blocks.

In another aspect the invention provides a method of lifting an object or a part thereof comprising the steps of: (a) placing a jacking device according to the first aspect of the invention under the object or the part thereof; (b) turning the drawbolt to draw the wedge toward the head of the drawbolt using a torque wrench.

The invention will now be more particularly described with reference to the accompanying drawings, in which: Figure 1 is a side view of one embodiment of a jacking device, according to the invention; Figure 2 is a central section through the jacking device of Figure 1 in the plane of the paper and with the draw bolt omitted; Figure 3 is a right hand view of the jacking device of Figure 1; Figure 4 is a plan view of the wedge of Figures 1-3; Figure 5 is a plan view of the lower surface block, the upper surface block being identical; and Figure 6 shows schematically a further embodiment of a jacking device according to the invention.

Referring to Figures 1-5 of the drawings, the jacking device shown therein comprises an upper block 10, a lower block 11 and a wedge 12 interposed between the two blocks 10 and 11.

The facing inner surfaces 13 and 14 of the blocks 10 and 11 respectively are in this case symmetrically inclined with respect to a central horizontal plane 15 parallel to a major outer surface 1 6, 1 7 of each block. Each block 10, 11 has two side flanges 1 8 (see Figure 3) for maintaining transverse alignment between the wedge 12 and the blocks 10 and 11. However, instead of the side flanges 1 8 each block could for example have one or more pins projecting into a slot in the wedge 12 or vice versa.

The wedge has two surfaces each of which lies parallel to and makes sliding frictional contact with the respective surface 13, 14 of the blocks.

The wedge also has a threaded hole 1 9 at its thick end which leads firstly into an unthreaded larger diameter hole 20 and then into a slot 21 at the thin end of the wedge (see Figures 284).

A drawbolt 22 has a head 23 at one end and a threaded portion 24 at its other end. It also has an associated bearing washer 25 and two hardened thrust washers 27 and 28. The threaded portion 24 of the drawbolts can be engaged with the threaded hole 1 9 in the wedge by inserting through a pair of aligned slots 26 in the blocks 10 and 11 (see Figure 5) and through the slot 21 and a hole 20 in the wedge. However, instead of providing a thread in the hole 19, a nut 29 (shown in broken lines in Figure 2) may be held captive against rotation in a recess in the thick end of the wedge.

In the lowermost position of the jacking device (see Figure 2), the side flanges 18 of the upper block 10 lie on the side flanges 18 of the lower block 11 and the wedge 1 2 projects outwards from the thick end of the wedge shaped cavity between the two blocks. The jacking device can be placed in this condition beneath, for example, a column, such as a steel column which is to take the load of a concrete column which has begun to deteriorate. Then, the drawbolt 22 can be engaged with the threaded hole 1 9 as aforesaid.

By tightening the drawbolt, the wedge 12 will be drawn towards the thinner end of the wedge shaped cavity between the blocks 10 and 11 to thereby increase the separation between the major outer surfaces 1 6, 1 7 of the blocks (see Figure 1) and to raise the steel column. The washer 25 restrains relative fore and aft movement of two blocks 10 and 11. In this way, the load on a deteriorating concrete column can be taken by one or more steel columns. The jacking devices is then, of course, left in place.

The angle of inclination of each inner surface 1 3, 14 to the central plane 1 5 is preferably about 7 . This has the advantage that the effort required to turn the drawbolt 22 is at an acceptable level.

Moreover, even if the drawbolt is released after the jacking device has been raised, it should hold its position.

The surface of the wedge 12 in contact with the inner surfaces 13, 14 of the two blocks 10, 11 may be greased. In order to achieve this, grease nipples 30 (shown in broken lines in Figure 2) may be provided in the thick end of the wedge with passages 31 (also shown in broken lines in Figure 2) leading to the surfaces of the wedge in contact with the facing inner surfaces of the two blocks.

The facing inner surfaces 13, 14 of the two blocks need not be symmetrically inclined with respect to a central horizontal plane parallel to a major outer surface of each block and, indeed, it is even possible that one of the facing inner surfaces 13 or 14 of the two blocks could be parallel to said central horizontal plane.

A double wedge arrangement is shown schematically in Figure 6, in which there are two outer blocks 50 and 51, an intermediate block 52 and two wedges 53 and 54. The angles of the two wedges can differ so that the wedge with the higher angle of inclination can be moved first and when the load is too great to move it further, the wedge with the smaller angle of inclination can then be moved.

In all the above embodiments, the drawbolt be tightened by a torque wrench acting if necessary through a torque multiplier.

In the above embodiments, one of the blocks 10 and 11, or 50 and 51 could be part of the structure to be jacked.

Claims

1. A jacking device comprising at least two blocks arranged one above another and a wedge interposed between two adjacent blocks, the upper surface of the uppermost block and the lower surface of the lowermost block being in parallel spaced relationship, at least one of the facing inner surfaces of adjacent blocks being inclined with respect to the upper surface of the uppermost block and the lower surface of the lowermost block, the wedge having two converging surfaces which lie parallel to and make sliding contact with the facing inner surfaces respectively of the two adjacent blocks, means for maintaining alignment between the wedge and the blocks in a direction normal to the direction of movement of the wedge relative to the blocks and parallel to the upper surface of the uppermost block and the lower surface of the iowermost block, a threaded drawbolt with a head at one end for moving the wedge along the facing inner surfaces of the two adjacent blocks to increase the separation between the upper surface of the uppermost block and the lower surface of the lowermost block, the drawbolt extending into a hole in the wedge from the thin end of the wedge and engaging with a thread in the hole or with a threaded nut, and a washer between the head of the drawbolt and an end surface of each of the two adjacent blocks to maintain alignment between the two adjacent blocks in the direction of movement of the wedge.

2. The jacking device of claim 1, wherein the alignment maintaining means comprises side flanges on each of the blocks.

3. The jacking device of claim 1 or claim 2, wherein the facing inner surface of the two adjacent blocks are symmetrically inclined with respect to a plane parallel to the upper surface of the uppermost block and the lower surface of the lowermost block.

4. The jacking device of any one of the preceding claims, wherein there are only two blocks.

5. The jacking device of any one of claims 13, wherein there are at least three blocks and two wedges, one between each pair of adjacent blocks and each having an associated drawbolt.

6. The jacking device of claim 5, wherein the heads of the drawbolts are at the same end of the jacking device.

7. The jacking device of claim 5 or claim 6, wherein the angle of convergance of the two converging surfaces of one of the wedges is greater than that of the or each other wedge.

8. The jacking device of any one of the preceding claims, wherein grease nipples are provided in the thick end of the or each wedge with passages leading to the surfaces of the or each wedge in contact with the facing inner surfaces of the two adjacent blocks.

9. Ajacking device substantially as herein before described with reference to any one of the embodiments shown in the accompanying drawings.

10. A method of lifting an object or a part thereof comprising the steps of: (a) placing a jacking device according to any one of the preceding claims under the object or the part thereof (b) turning the drawbolt to draw the wedge towards the head of the drawbolt using a torque wrench.

11. The method of claim 9, wherein the torque wrench acts through a torque multiplier.