GB2296230A

GB2296230A - Cable through-feed

Info

Publication number: GB2296230A
Application number: GB9523727A
Authority: GB
Inventors: Cornelis Stinis
Original assignee: Stinis Beheer BV
Current assignee: Stinis Beheer BV
Priority date: 1994-12-23
Filing date: 1995-11-20
Publication date: 1996-06-26
Also published as: NL9402198A; GB9523727D0

Abstract

A cable through-feed (8), is primarily for use with a multi-core electricity cable (7) extending between a crane and a spreader for loading and unloading transport containers. It is important for superfluous cable (7) to be stored in a cable holder (6) and not form a loop above the cable holder (6). The cable through-feed (8) has at least three driven, rotatable guide rollers (9, 10, 11, 12) which collectively define a through-feed opening. <IMAGE>

Description

CABLE THROUGH-FEED The present invention relates to a cable through-feed for use in association with a cable and a cable holder, and is more especially but not exclusively concerned with a cable through-feed for use in further association with a spreader suspended from a crane.

Use is made of so-called spreaders to take hold of transport containers. A spreader usually includes a frame to which are attached rotatable locks which can be coupled to openings arranged in the corners of a container (the corner castings). The spreader is usually suspended from a crane of the kind used in harbours for loading and unloading of container ships. For power supply to the spreader, and for communication between the spreader and the crane, a connecting cable is arranged between the crane and the spreader. This is usually a multi-core power cable, which may or may not be provided with glass fibres.

In order to counteract, during use, the changes in the distance between the spreader and the crane, provisions are required to buffer the unneeded portion of the connecting cable. These provisions must prevent the connecting cable from making uncontrolled movements resulting in the cable being damaged or causing an obstruction.

A comparatively advantageous solution is a cable holder arranged on top of the spreader. Here can be envisaged a space or cage which is opened on the top side and the opening of which can taper in a funnel. When the spreader is moved upward the portion of the cable which has become superfluous is carried by the force of gravity into the holder, optionally via the funnel. When the spreader moves downward the cable is pulled out of the holder since the top part of the cable is fastened to the crane.

A great drawback to this relatively inexpensive cable holder, however, is that the cable can form a loop to the side of the funnel as a result of swinging of the spreader, rapid vertical movements of the spreader and/or wind. This must then be remedied before further work can be done with the spreader, and during remedying of the problem not only are the spreader and the crane inoperative but loading and unloading also ceases, which can have serious financial consequences.

The object of the invention is to provide an improved through-feed for a connecting cable between a crane and a spreader which is less susceptible to malfunction during operation than the solutions known up to the present time.

The invention provides for this purpose a cable through-feed, for use in association with a cable and a cable holder, comprising at least three driven, rotatable guide rollers which collectively define a through-feed opening.

The through-feed opening defined by the rollers is preferably larger than the cross-section of the cable. The rotatable guide rollers can be moved depending on the direction of movement of the spreader such that the frictional resistance between the rollers and the cable is markedly reduced. When the through-feed opening is larger than the cross-section of the cable, the resistance between the rollers and the cable will remain very limited in the case that the latter is carried perpendicularly through the opening.

However, as soon as the cable is carried through the opening at a determined angle, contact will occur between at least two of the guide rollers and the cable. In the case of an even number of guide rollers this will involve at least two mutually opposite guide rollers. Because contact has now been made between the rollers and the cable it is possible to exert forces on the cable using the rollers. In practice, as soon as a loop begins to form in the cable, the latter will enter the through-feed opening at an angle. This is also the moment at which a correction must be made. This is possible by means of the driven guide rollers; these engage on the cable precisely at this desired moment whereby they can carry thn cable inward more rapidly.The moment at which this takes place (the angle at which the cable must be situated) depends on the geometric difference between the cross-section of the cable and the through-feed opening.

For the sake of completeness, it is stated here that the cable does not have to have the same cross-section along its whole length, and that the cross-section of the cable can vary in the course of time without necessarily interfering with the good operation of the cable throughfeed.

A preferred embodiment of the cable through-feed is characterised in that at least one of the guide rollers is mounted on a shaft for rotation about a shaft axis, with the shaft being pivotable about a pivot axis which lies substantially perpendicular to the shaft axis. The shaft is preferably also provided with locking means for locking the shaft in a working position relative to the pivot axis.

By means of these steps it is possible to carry objects which are larger than the through-feed opening in or out of a cable holder in a comparatively simple manner.

The guide rollers are preferably connected by couplings allowing the guide rollers to be driven by one drive. Due to this step not every guide roller has to be provided with a separate drive.

Also preferably, there are four of the guide rollers arranged as a cruciform, with each of the guide rollers having a concave circumferentially extending guide face.

The invention will be further elucidated with reference to the non-limitative embodiment shown in the drawings, in which: Figure 1 shows a perspective view of a spreader with a cable through-feed according to the invention; Figure 2 is a partly cut away enlarged perspective view of the cable through-feed of Figure 1; and Figure 3 is a top view of the cable through-feed of Figure 2 in an opened condition.

Spreader 1 shown in Fig. 1 is connected to a crane (not shown) by means of hoisting cables 2. Arranged at the corners of spreader 1 are locks 3 for coupling and decoupling containers 4. The corners of containers 4 are provided for this purpose with so-called corner castings 5 which co-act with the locks 3. Situated on the top of spreader 1 is a cable holder 6 in which the unneeded portion of a connecting cable 7 can be buffered.

Connecting cable 7 serves as a power supply to the spreader 1 and also allows exchange of information between the spreader 1 and the crane (not shown). Connecting cable 7 is thus usually formed by a multi-core electricity cable which may or may not be provided with glass fibre connections. The power supply is intended inter alia for driving the locks 3. The information exchange can include for instance measurement data from sensors arranged on spreader 1 and control signals. On the cable holder 6 is arranged a cable through-feed 8 which is the subject of the present invention.

Figure 2 shows the cable through-feed 8, the upper part of cable holder 6 and part of connecting cable 7. The cable through-feed 8 comprises four guide rollers 9-12 which are mutually coupled by means of toothed bevel wheels 13 (Fig. 3). Guide rollers 9-12 are connected to a drive 15 by an output shaft 14. By making the rotation speed and the rotation direction of guide rollers 9-12 dependent on the direction of movement of spreader 1, the frictional resistance between connecting cable 7 and guide rollers 912 can be markedly reduced. However, because the throughfeed opening 16 (Fig. 3) defined by guide rollers 9-12 is larger than the cross-section of connecting cable 7 this frictional resistance will in any case be small. At the moment a loop begins to form in connecting cable 7 on the top of cable through-feed 8, the cable 7 will come to lie at an angle to the vertical close to the cable through-feed 8. Because the through-feed opening 16 is only to a limited extent larger than the cross-section of connecting cable 7 the latter will, due to its inclining position, make contact with at least two mutually opposite guide rollers 9-12. Through this contact it becomes possible to exert a force on the connecting cable 7 using the guide rollers 9-12 such that the loop in the connecting cable 7 situated on the top of cable through-feed 8 is removed.

Finally, the cable through-feed 8 is provided on the top side with a rounded ring 17 whereby damage to the outer sheath of connecting cable 7 is prevented during the possible short-lived presence of a loop.

Figure 3 shows in top view the cable through-feed 8, wherein two guide rollers 11, 12 with their associated toothed bevel wheels 13 are pivoted outward on vertical rotation shafts 18, 19. Outward pivoting of the guide rollers 11, 12 has the object of enlarging the through-feed opening 16 such that larger objects such as a plug can be placed manually through the cable through-feed 8. The plug can be such as to connect the cable 7 to the electrical circuitry of the spreader 1. It thus becomes possible to carry objects for instance with a diameter as shown with a dashed circle 20 into or out of the cable holder 6.

Claims

1. A cable through-feed, for use in association with a cable and a cable holder, comprising at least three driven, rotatable guide rollers which collectively define a through-feed opening.

2. A cable through-feed according to claim 1, wherein at least one of the guide rollers is mounted on a shaft for rotation about a shaft axis, with the shaft being pivotable about a pivot axis which lies substantially perpendicular to the shaft axis.

3. A cable through-feed according to claim 2, wherein the shaft is provided with locking means for locking the shaft in a working position relative to the pivot axis.

4. A cable through-feed according to any preceding claim, wherein the guide rollers are connected by couplings allowing the guide rollers to be driven by one drive.

5. A cable through-feed according to any preceding claim, wherein there are four of the guide rollers arranged as a cruciform, with each of the guide rollers having a concave circumferentially extending guide face.

6. A cable through-feed substantially as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.

7. A cable through-feed according to any preceding claim, wherein the cable through-feed is fixed to a cable holder into which a cable extends through the cable through-feed.

8. A cable through-feed according to claim 7, wherein the through-feed opening defined by the guide rollers is larger than the cross-section of the cable.

9. A cable through-feed according to claim 7 or claim 8, wherein the cable is a multi-core electricity cable.

10. A cable through-feed according to any one of claims 7 to 9, wherein the cable holder is fixed to a spreader which is suspended from a crane.