GB2201137A - Hoisting apparatus - Google Patents

Abstract

A rig for raising an elongate object comprises a yoke (2) supportable from a crane and a pair of chain blocks mounted in the yoke and driven in synchronism in opposite directions so that one pays out chain (25) at the same rate as the other takes in chain (26). Each chain block may have its own chain or a common chain may be used. The drive is effected by a hand chain (15) or an electric motor connected to a wheel (14) which drives the chain blocks by endless chains (23, 24). The rig is used to raise an elongate article lying on the ground to a vertical position. <IMAGE>

Description

RIG This invention relates to a rig for raising an elongate object into a position where its axis is substantially vertical. In this position the object can be rotated about its longitudinal axis.

It can be difficult to turn over a heavy elongate object which is lying on the ground. It is an object of the present invention to provide a rig for connection to a hoist or crane and which enables such an object to be safely turned over.

According to the present invention, a rig for raising an elongate object comprises a yoke adapted to be pivotally supported by a crane, hoist or the like, a pair of chain blocks mounted in the yoke and actuating means for actuating the chain blocks in synchronism with each other so that one block pays out chain at the same rate as the other takes up chain-and vice versa.

In one preferred form of the invention, the actuating means comprises a drive wheel drivingly linked to the chain blocks and a hand chain engaged with the drive wheel. In an alternative embodiment, the actuating means comprises an electric motor. In this latter case, provision may be made for controlling the electric motor by remote control with the aid of an infra-red or radio transmitter.

The chain blocks are arranged so that one block pays out chain whilst the other takes up chain or vice versa. A single length of chain may pass through both blocks. Preferably, however, each block has a separate respective length of chain associated therewith; in this way, adjustment of the rig to accommodate objects of differing length is facilitated.

In order that the invention may be more readily understood, it will now be described, by way of example only, with referenceto the accompanying drawings, in which: Figure 1 is a side view of a rig constructed according to the invention; Figure 2 is'a cross-section on the line A-A of Figure 1 (with chain guard, chain box and chain retainer omitted); and Figure 3 is an end view of the rig of Figures 1 and 2.

Referring to the drawings, rig 1 comprises a yoke 2 which is pivotally secured to a bow shackle 3 which, in turn, can be supported from a crane or hoist (not shown). Yoke 2 comprises a pair of plates 4, 5 which are held separated one from another near their upper ends by spacers 6 and bolts 7. Near their lower ends, plates 4, 5 carry chain blocks 8, 9 which are held in position by means of links 10, 11 and bolts 12.

(For the sake of clarity, bolts 12 are omitted from Figure 2). Chain blocks 8, 9 are of conventional type; for example, they may be 1 tonne SWL blocks sold by Lloyds British Testing Company Limited of Atlas House, Belwell Lane, Sutton Coldfield, West Midlands B74 4AB under the trade mark "VITAL", Model 10 VH. Such chain blocks allow chain to be paid out or taken up at all times under full braking control.

An operating shaft 13 is also mounted in yoke 2. This carries a hand wheel 14 at one end, which is best seen in Figures 2 and 3, over which passes a hand chain 15 in the form of an endless loop. A counter balance 16 is mounted on the opposite side of yoke 2 from chain wheel 14. Reference numerals 17, 18 indicate a pair of bearing supports forhaft 13.

Shaft 13 also carries a pair of chain wheels 19, 20, one on each side of yoke 2, which are drivingly connected to the corresponding actuating wheels 21, 22 of chain blocks 8, 9 by means of respective roller chains 23, 24 so as to cause actuating wheels 21, 22 to rotate in synchronism with operating shaft 13 and hand wheel 14. Because chain blocks 8, 9 are mounted so that their respective actuating wheels 21, 22 are on opposite sides of yoke 2, rotation of hand wheel 14 in an anti-clockwise direction, as viewed in Figure 1, causes chain 25 to be paid out from block 8 whilst chain 26 is taken up by block 9. (Only part of each chain 24, 25 is shown in the drawings). Upon reversing the direction of rotation of hand wheels 14, chains 25 and 26 move in opposite directions, being taken up by chain block 8 and paid out by chain block 9, respectively.In each case, the movement of the chains 25, 26 is always under braking control.

Reference numeral 27 indicates a chain stop.

A chain guard 28 is supported above hand wheel 14 by means of strut 29. Chain boxes 30, 31 are provided to hold the ends of chains 25, 26 which have not been paid out. Roller chains 23, 24 are shielded by respective chain boxes 32, 33.

At the lower ends, the paid out parts of chains 25, 26 may each carry a hook or shackle (not shown).

The operation of the illustrated rig 1 will now be described with reference to use thereof for picking up and turning over a heavy elongate object, such as a wing spar, which is lying initially with its axis extending horizontally. The rig 1, supported from a crane hook (not shown) is positioned at an appropriate height above the wing spar and the lengths of the paid out parts of chains 25, 26 are adjusted (by operation of the hand chain 15) until the hooks or shackles at their lower ends are positioned conveniently for lifting the wing spar. After attaching such hooks or shackles to the wing spar, one near each end thereof, the rig is lifted by the crane or hoist until the wing spar is sufficiently far above the ground for it to be turned over. The length of the paid out parts of chains 25, 26 must also be sufficiently long to permit this turning movement to take place.

Next, the hand chain 15 is operated. This causes one of the chains 25, 26 to be paid out and the other to be taken up. As a result, one end of the wing spar is lifted whilst the other end is lowered.

This movement is continued until the wing spar is hanging substantially vertically with all its weight hanging on one of the chains 25, 26. Pivoting of the and of the yoke 2 relative to shackle 3, permits the rig 1 to accommodate the changing forces experienced as tte-wing spar is brought into this position.

In this position, it is relatively easy to manually rotate the object, whilst suspended, with its longitudinal axis vertical. After it has been rotated through 180 degrees, the direction-of rotation of the hand wheel 14 is reversed so that the chain which had previously been paid out is now paid in and vice versa.

This causes the wing spar to be returned to the horizontal position but with the spar having been turned over. When the spar is in the horizontal position, the rig is then lowered to deposit the rig on the ground or other convenient support surface.

As the movement is carried out under the braking control of the chain blocks 8, 9, the operation is always under the full control of-the operator.

In a modification of the illustrated rig, an electric motor replaces hand wheel 14 and hand chain 15. Such a motor can be operated under remote control using, conveniently, a hand held remote control unit utilising an infra-red or radio beam for communication purposes.

Claims (6)

Claims:

1. A rig for raising an elongate object comprising a yoke adapted to be pivotally supported by a crane, hoist or the like; a pair of chain blocks mounted in the yoke and actuating means for actuating the chain blocks in synchronism with each other so that one block pays out chain at the same rate as the other takes up chain and vice versa.

2. A rig as claimed in claim 1, in which the yoke is supported from said crane, hoist or the like by way of a support shackle pivotally mounted on the yoke.

3. A rig as claimed in claim 1 or 2, in which actuating wheels on the yokes are chain driven from a common shaft rotatably mounted in the yoke.

4. A rig as claimed in claim 3, in which the shaft is rotatable by a continuous chain passing over a wheel mounted on the shaft.

5. A rig as claimed in claim 3, in which the shaft is in driving relation with an electric motor mounted on the yoke.

6. A rig for raising an elongate object substantially as hereinbefore described with reference to the accompanying drawings.