EP0190248A1

EP0190248A1 - Cable winding apparatus.

Info

Publication number: EP0190248A1
Application number: EP85903862A
Authority: EP
Inventors: Colin Peter John Dickenson; Philip Sydney Dixon
Original assignee: LEBUS INTERNATIONAL ENGINEERS Ltd; LEBUS INT ENG Ltd
Current assignee: LEBUS INTERNATIONAL ENGINEERS Ltd; LEBUS INT ENG Ltd
Priority date: 1984-08-06
Filing date: 1985-08-06
Publication date: 1986-08-13
Also published as: NO861327L; DE3563842D1; NO163482B; WO1986001189A1; DK153022B; FI79822B; FI861116A0; FI79822C; ATE35805T1; EP0190248B1; DK155786D0; NO163482C; GB2162811B; GB2162811A; FI861116A; GB8419964D0; DK155786A; DK153022C

Abstract

Cable winding apparatus comprises a cylindrical drum (1) adapted to hold a plurality of layers of cable wound thereon. The drum has circumferential primary grooves (2) around at least parts of its periphery for accommodating the innermost layer of cable. The cable is arranged to unwind progressively from a first end of the drum to the opposite second end. Secondary grooves (5) are formed in the base of the primary grooves. The secondary grooves are of smaller diameter than the primary grooves and are adapted to accommodate a tail line attached to the innermost end of the cable but of correspondingly smaller diameter. After unwinding of the cable, the tail line will unwind progressively from the second end to the first end of the drum.

Description

CABLE WINDING APPARATUS

This invention relates to cable winding apparatus. The apparatus is suitable for receiving and dispensing substantially any type of wire cable, electric lines, rope, cored and the like (hereinafter referred to collectively as "cable").

Cable winding apparatus of various kinds is known and in common use. Such apparatus is used in the oil field industry, both offshore and land based, and also for general marine equipment. Other applications include crane, winch and vehicle-mounted systems. The apparatus according to the present invention is suitable for use in all of these fields. Particular attention has been directed to achieving some sort of control over the manner in which cables are wound upon drums or spools, particularly when the cable is frequently extended and under tension. Apparatus of this kind is described in GB-A 737352 and GB-A 776007.

In the past, problems have been experienced through the hoisting ropes on offshore marine and constructional cranes beeoming snagged or unintentionally attached to other objects, e.g. offshore support vessels, moving vehicles etc. Such hoist ropes have a uniform diameter, and if they become trapped at the drum or entangled in the reeving arrangement or structure of the machine, then the lifting machine, e.g. crane or winch, may be pulled off its pedestal or mounting base. This has resulted in extreme damage and loss of life in certain instances. An object of the present invention is to avoid the disadvantages referred to above. This is achieved by attaching the innermost end of the cable to a tail line which is of smaller diameter than the cable and has a relatively low load bearing capacity. The main hoist rope or cable may thus be allowed to pass freely through the rigging system of the machine, followed by the attached secondary rope or tail line, which can ultimately be allowed to break free from the drum anchorage once sufficient cable and tail line have run through clear of the machine. The tail line controls the passage of the cable by maintaining a tension in the cable as it passes through the reeving system, and the tail line has a substantially lower breaking strength compared with the load bearing capacity of the machine upon which it is mounted. Thus, a snagged vessel or falling load attached to the free end of the cable cannot in turn pull the hoisting machine from its mounting. Furthermore, when using the technique in reverse, the small tail line can be utilised to feed the cable more easily through the rigging sheaves or reeving system of the machine upon which the drum is employed. The invention moreover simplifies the accommodation of the tail line or cable when wound on or off a drum arranged to accommodat e one or more layers of cable.

Should the hoisting machine malfunction, owing to power or brake failure or mechanical breakdown, thereby all owing the load to run free, then the cable will pay off the winch drum to its fullest extent without the problem of the cable re-winding in the reverse direction back onto the drum. Thus, the invention provides cable winding apparatus comprising a cylindrical drum, a cable adapted to be wound on or off said drum, and a tail line attached at one end to an end of the cable and at the other end to the drum and also adapted to be wound on or off the drum, the tail line having a lower load-bearing capacity than the cable and being adapted to snap under stress or to pull free from the drum having unwound to its full extent.

Where one or more layers of rope or cable are wound onto a drum, it is benef icial to ensure that control led spool ing is maintained through al l layers.

Particular designs of drum for obtaining such control led spool ing are described, for example, in GB-A 737352 and

GB-A 776007.

In another embodiment, the invention provides cable winding apparatus comprising a cylindrical drum adapted to hold a plurality of layers of cable wound thereon, the drum having circumferential primary grooves around at least part of its periphery for accommodating the innermost layer of cable such that said layer will unwind progressively from a first end of the drum to the opposite second end, characterised in that secondary grooves are formed in the base of the primary grooves, the secondary grooves being of smaller diameter than the primary grooves and adapted to accommodate a tail line attached to the innermost end of the cable but of correspondingly smaller diameter, whereby, after unwinding of the cable, the tail line will unwind progessively from the second end to the first end of the drum.

The provision of the secondary grooves for the tail line, indicated above, is applicable for various designs of the circumferential primary grooves. In a particularly preferred embodiment, two sets of diametrically opposed circumferential primary grooves are provided on the periphery of the drum and positioned parallel to the ends of the drum. The grooves of one set are disposed side-by-side but displaced relatively to the grooves of the other set. These two sets of main or primary grooves are each of a length less than half the circumference of the drum, thereby providing a pair of axially extending diametrically opposed cable control zones on the periphery of the drum. The secondary smaller grooves are formed in the base of the main grooves described above, the secondary grooves being formed in the opposite direction across the barrel width to that of the main grooves, i.e. if the main groove is righthand wound, then the secondary groove is lefthand wound, and vice versa. This relationship remains the same whether the drum is overwound or underwound with cable. The tail line groove runs from a starting position determined by the lenqth of tail line reauired following a path through the bottom of the primary groove but in opposing direction with crossover sections of the groove coinciding at two radially opposing areas around the drum. The secondary groove runs into the main groove at a predetermined position adjacent to one flange.

The arrangement of grooves described above may be integrally applied onto the dr um core or barrel. Alternatively, the grooving may be applied to a plain barrel as an additional split wrapper, sometimes known as lagging or sleeve, around the main drum.

Reference is now made to the accompanying drawings, in which: Figure 1 is a side view of the drum of a cable winding apparatus according to a preferred embodiment of the invention;

Figure 2 is a developed sur face plan view of the apparatus shown in Figure 1 ; Figure 3 is a partial sectional view taken along the line 3-3 of Figure

2; and

Figure 4 is an end view of the drum of Figure 1 . The drawings show a drum 1 having an arrangement of circumferential primary grooves 2 designed for controlled cable spooling. This arrangement of the primary grooves is known in itself and is described for example in GB-A 776007. The primary grooves are arranged in two diametrically opposed sets each parallel to the ends of the drum, but one set being displaced axially with respect to the other set by one half the width of the grooves. Each set of grooves is of a length less than half the circumference of the drum, so there is provided a pair of axially extending, diametrically opposed cable control zones 3 on the periphery of the drum. Such control zones may be plain, or as actually shown in the drawings may be provided with a set of helical grooves which communicate between the adjacent ends of the two main sets of grooves. In conventional manner, end fillers 4 are provided a t both ends of the drum to guide the cable between the two sets of primary grooves, and hence obtain controlled spooling. Thus, in each of the regions of helical grooves, the cable is shifted axially by a half pitch. In accordance with the invention, there is formed in the base of the primary grooves the secondary grooves 5. These are of smaller diameter than the primary grooves, and correspond to the diameter of the tail line, which is correspondingly of smaller diameter than the cable. The grooving of the secondary grooves is of the opposite hand to that of the primary grooves. This is achieved by machining the secondary grooves so that they crossover the primary grooves in the region 3 of the two sets of helical grooves. Two sets of crossover points therefore coincide on diametrically opposite sides of the drum.

The cable is joined to the tail line in the region where the secondary groove 5 commences, near the end of the cable starting end filler. The joints between the cable and the tail line is desirably as short as possible to minimise the unsupported length of the second layer of cable. As shown in the drawings, the secondary groove 5 then passes, in opposite hand to the main groove, to the opposite end of the drum where the tail line passes through the drum barrel and is secured in known manner, alternatively at a point along the width of the barrel determined by the length of tail line required. The above arrangement is of assistance in winding the cable through associated reeving systems and onto the drum. The tail line is first passed through to the drum and is secured to the side of the drum near one end of the secondary groove. The drum can then be rotated and first the tail line and then the cable are wound onto the drum in controlled manner.

If, in use, the cable becomes snagged or attached to a runaway load, the following safety features of the invention come into operation. The cable is allowed to run out freely through the reeving system and is maintained under tension because it is attached to the tail line. The tail line then in turn passes through the reeving until it is either completely unwound from the drum or snaps under stress, as it has a substantially lower breaking strength than the load bearing capacity of the drum and associated apparatus. Thus, although the cable might be lost in such circumstances, the cable winding apparatus itself remains substantially undamaged.

Claims

1. Cable winding apparatus comprising a cylindrical drum, a cable adapted to be wound on or off said drum, and a tail line attached at one end to an end of the cable and at the other end to the dr um and also adapted to be wound on or off th um, the tail line having a lower load-bearing capacity than the cable and being adapted to snap under stress or to pull free from the drum having unwound to its full extent.

2. Cable winding apparatus according to claim 1, comprising a cylindrical drum adapted to hold a plurality of layers of cable wound thereon, the drum having circumferential primary grooves around at least part of its periphery for ac com mo da t i ng the innermost layer of cable such that said layer will unwind progessively from a first end of the drum to the opposite second end, characterised in that secondary grooves are formed in the base of the primary grooves, the secondary grooves being of smaller diameter than the primary grooves and adapted to accommodate a tail line attached to the innermost end of the cable but of correspondingly smaller diameter, whereby, af ter unwinding of the cable, the tail line will unwind progressively from the second end to the first end of the drum.

3. Cable winding apparatus according to claim 2, in which the primary grooves are arranged in two diametrically opposed sets and positioned parallel to the ends of the drum, the grooves of one set being disposed side-by-side butdisplaced axially relative to the grooves of the opposite set, and each of the two sets being of a length less than half the circumference of the drum to provide a pair of axially extending, di ame trically opposed cable control zones on the periphery of the drum.

4. Cable winding apparatus according to claim 3, in which helical primary grooves are arranged in the cable control zones to communicate between the adjacent ends of the two sets of parallel primary grooves and to shift the cable axially by half a pitch.

5. Cable winding apparatus according to claim 4, in which the secondary grooves crossover the primary grooves in the regions of helical grooving.