GB2321047A

GB2321047A - Multiple Action Gantry Crane

Info

Publication number: GB2321047A
Application number: GB9700637A
Authority: GB
Inventors: Philip Henry Bacon
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-01-14
Filing date: 1997-01-14
Publication date: 1998-07-15
Also published as: GB9700637D0; EP0952955A1; HK1023551A1; AU5566798A; EP0952955B1; DE69810075D1; DE69810075T2; WO1998030485A1

Abstract

A crane constructed with two or more lifting tackles suspended from trolleys 41 and 42,43 that are capable of moving along the functional length of the supporting gantry by passing clear of each other when crossing. This may be attained by the trolleys running in parallel tracks (Fig 1) and the tackles with loads swinging clear of each other when crossing; or can be attained by the tackles being suspended from tiered trolleys or half-trolleys successively wider to each other and having the the narrower tackles and lifts 41 lifting through inside the wider set(s) 42,43 when crossing.

Description

The Multiple Action Gantry Crane (MAG) This invention relates to a multiple action Gantry Crane, which would essentially require multiple tracks on it's gantry.

The productivity of several segments of industry has been limited in some operations by the maximum amount of lifting operations a crane is able to do in a given period of time, and the fact that a second or other cranes would not be able to work at the same location due to the physical presence of the structure of the first crane.

The Multiple Action Gantry Crane is conceived as a means to operate two or more lifting tackles running along a same gantry; thus, in effect, allowing the operator to have two or more cranes working in the same location.

So as to be able to operate two or more lifting tackles with their respective trolleys along the same gantry in such a fashion as to emulate two or more cranes working in the same location, it is fUndamental that these should be able to pass clear of each other on the gantry while having their load under tackle and again when returning. Also it is clear that the structure of the gantry itself and it's legs (or other supports) must be capable of working safely with the combined weights, momentum and vibrations of the simultaneous multiple lifts: however this should be specified by the builders and commissioners of the individual crane.

Two forms of attaining the objective described in the previous paragraph will now be described by way of example, making reference to the accompanying drawings in which: Figure 1 presents a typical section (front view) of the gantry with parallel tracks and two trolleys with their tackles; Figure 2 shows in perspective a simplified structure of a gantry with two tackles crossing clear of each other in a tiered setup; Figure 3a shows a typical section (front view) of the gantry with tiered tracks, where the trolleys span the width ofthe tracks; Figure 3b shows a plan (seen from underneath) view of the situation as in 3a, including the ends of the gantry to demonstrate attachment to the support structure; Figure 4 presents a typical section (front view) of the gantry with tiered tracks, with halftrolleys; Figure 5 presents a typical section of the situation as in Fig 4, however detailing the wire arrangements in case of unitised lifts; Figure 6 presents a profile view of a gantry crane with graphical representation of a collision prevention zone.

One way to attain the multiple action objective, in the case of two tackles, is to have the trolleys 10 running in parallel tracks 11, side by side as in Fig 1. The wires working from the sheaves 12 closer to the centreline between the two trolleys would be those actually taking most of the lift when the tackle were at pickup and dropping level (as is tackle A in Fig 1). The wires working from the sheaves 13 at the ends further from the centreline between the trolleys, are used of course for stabilising the lift for sway, but essentially to swing tackle and lift outwards and away from the centreline, so as to pass clear of the other tackle when moving along the gantry (as is tackle B in Fig 1).

This method of attaining MAG capability is advantageous due to the relatively simple mechanics and allowance for conventional structure of the gantry itself. It must however be noted that each of the two tackles would not, in theory, be able to reach exactly the same point on the centreline and therefore this method is more pertinent to work of not very precise nature (e.g. grab lifts of bulk commodities from a stockpile or ship's hatch).

Another way to attain multiple action operation on a single gantry is for the two or more trolleys to be wider than each other by stages. The general principle of this solution is that the wider trolleys would run in tracks just above or outside the narrower ones, with their wires reaching round the tackle of the narrower trolley(s) when they crossed along the gantry as in Fig 2; i.e. the narrower trolley has it's tackle 21 raised to a point where it will clear tackle and lift through inside the wires and tackle 22 of the "wider" trolley(s) as in Fig 2.

This tiered operation incurs a problem in how to physically sustain the tracks while allowing the wider tackle(s) to reach round the narrower ones). Two examples for solving this are covered below.

For the tiered operation of complete trolleys 31, 32... spanning the width of a pair of tracks 33, 34.. as in Fig 3a, it would be necessary for such track rails to only be connected to the structure of the gantry 35 at the extremities of their functional run (Fig 3b), so as to not obstruct the run 36 of the wider trolley(s) 31 and it's (their) tackle with the supporting structure of the narrower trolley's 32 tracks 34. This could prove difficult in view of certain working loads against steel or other gantry material strengths, however the mechanical composition of the trolleys themselves would be as in present conventional gantry cranes.

However another form of operating tiered trolleys is illustrated in Fig 4 and would be to have only the narrowest trolley 41 of present fashion (conventional) build, i.e. spanning the gap between the pair of tracks 44 with a single wheeled structure. The second and any further tackles would be sustained from separate "half-trolleys" 42, 43 running independently on tracks 45 each side, outside the first trolley. These pairs of trolleys would have to move in rigid conformity with each other, to be attained through being driven by synchronous electric motors, or controlled by microprocessors reading infrared signals from the other "half-trolley", or other electromechanical devices to the same effect.

In some sectors of industry the lifts are of unitised items of same dimensions, or the tackle has to be lowered into spaces only as wide as the lift itself In these cases it would be necessary for these provisions for MAG capacity to be combined with the use of wire spreaders and collectors as part of the tackle of the "wider" trolleys, so as to fit these restrictions.

For example, in the case of container ship loading and discharge, the lifts should be 40 feet wide for containers 50 of such dimension. Therefore the narrower trolley 51 and it's tackle 52 as in Fig 5 must have 40' as their maximum transverse dimension. Parallel tracked trolleys would not necessarily function in this case because the operator would most likely want both tackles to work on the same line. However if using tiered trolleys, the "wider" trolley 53 would require internal dimensions larger than 40' to clear the first trolley 51; but it's tackle 54 would have to be brought down to 40' width to reach into the slots on the ship 55 and lock onto another container 50. For this a wire "collector" frame 56 would have to be suspended (in example, by wires 57) below the point where the narrower trolley will clear it's lift through the wider tackle.

In the case of manually driven cranes, the driver's cabs would be attached to the trolleys or one of the half-trolleys so as to follow the movement of the respective tackle. If the clearances are critical (as with unitised lifts), the cabs could run on further independent tracks outside, to be synchronised with the trolleys they command as described before.

The safety to be considered in any of the MAG possibilities for a crane, is primarily that of a collision between the two or more lifts, tackles and/or wires. For this, electromechanical sensors and cutouts, microprocessor controlled brakes or other logical switching to the same effect should be put in place by the manufacturers according to the nature of the MAG commissioned, and detailed further in the next paragraphs.

For parallel track MAGs, the tackle and any lift of a trolley in movement along the gantry should be fully swung away from the centreline on approaching the other trolley; and if it is not so the above safety switching should cease the movement of the trolley.

For tiered trolley MAGs, the tackle 62 and any foreseeable height of a lift 61 would have to be retracted high enough by the narrower trolley to clear through the "outer" tackle 63 on approaching it's position on the gantry; and if it is not so, the above safety switching should cease the movement of the moving trolley if entering a given minimum distance 64.

Claims

1. A crane where two or more trolleys with their own tackles may pass clear of each other.

2. A gantry crane where two or more trolleys with their own tackles may operate independently of each otller along the functional length of the gantry.

3. A gantry crane where two or more trolleys with their own tackles and respective lifts may operate independently in parallel tracks on the same gantry.

4. A gantry crane where two or more trolleys with their own tackles and respective lifts may operate independently in tiered tracks, with their tackles and wires reaching round the narrower one(s).

5. A gantry crane where two lifts may be operated independently from each other along the functional length of the gantry, with the first trolley and it's tackle being narrower than the other(s), and where the wider tackles are suspended from half-trolleys on each side ofthe narrower one(s) with no physical link between them so as to pass clear of the narrower tackle(s) and structure of the gantry.

6. A crane as described in claim 4 or claim 5 above, where wire spreaders or collectors are employed to combine the objectives of the said claims with those of lifting loads into and out of restricted spaces.

7. A crane as described in claim 4 or claim 5 above, where wire spreaders or collectors are employed to combine the objectives of the said claims with those of lifting similar sized. standardised or unitised loads.

8. A crane substantially as herein described and illustrated in the accompanying drawings.