CABLE GUIDE FOR HOISTING DEVICES

Abstract: The present invention relates briefly to an arrangement for hoisting devices to keep a cable (10) substantially vertically stretched between a derrick or similar and a hoisting device, e.g. a derrick bridle (1), so that the cable will not be able to be depositioned by gusts and other factors. The arrangement consists of a set of brackets (12) stretched between and glidably fixed to two opposed hoisting cords (2a, 4a), the brackets (12) being equipped with a ring (13) approximately at their centre, through which ring the cable (10) is running with an increasing inner diameter for each ring (13) from the top downwards. To the cable (10) are fastened a set of elements (14) spaced apart with increasing diameter for each element from the top downwards for each inner diameter of the rings (13) so that each element (14) one by one is restricted to pass a corresponding ring (13) and thereby each is hoisting one by one a bracket (12) holding the cable (10).

Description: Cable Guide for Hoisting Devices The present invention relates to hoisting devices och especielly to a cable guide keeping a cable stretched between the derrick itself and the hoisting accessories being supported by the crane by means of cords as not to be effected and dislocated, especial¬ ly by gusts. In lifting load carrying bins, so called containers, special hoisting accessories are used, e.g. a derrick bridle, supported by hoisting cables from a derrick or similar being equipped with gripping elements to grip a container and during movement to retain it to the derrick bridle. The derrick bridle generally being adjustable to different container sizes has gripping ele¬ ments for retaining the containers, the elements being equipped with electromechanic and/or hydraulic components. Independent of the type of guiding devices being used a supply line for current to the derrick itself is necessary and so are lines for transmit¬ ting signals from different sensors of the derrick bridle to the operator cabin giving the derrick operator the possibility of in¬ forming himself of the operation position of the bridle. The invention being described in connection with a derrick bridle can, however, as known to those skilled in the art, been adapted to many different types of hoisting devices. The derrick bridle and its load being very heavy it will not be especially affected by winds. So is the case, however, with the cable, generally being stretched between the derrick or similar and the derrick bridle over a distance of upp to 30 to 40 m. The cable comprising a variety of different conductors has a compara¬ tively large diameter och so catches a great deal of wind. There has not to be a particular strong wind to affect the cable being anyhow of comparatively little weight and to push it sidewise out of the vertical of its normal position. This means that derricks today often are forced to stop operation at already rather mode¬ rate wind forces not by any means affecting the load per se, but the risque being rather large for a cable being pushed aside by the wind to hook on other objects or by other means being affec¬ ted by stresses causing it to break or to damage objects. There have been many different attempts for solving this problem of a cable being affected by winds. It has i.a. being tried to increase the weight of the cable by attaching chains to it and by trying to keep it stretched by means of various windlasses. None of these attempts has, however, been successfull, the cable in these cases being strained at its sockets and being exposed to rupture. The application of windlasses is a very expensive proce¬ dure for keeping such heavy elements as cables stretched. The present invention aims to overcome these problems mentioned above. The problem is solved with an arrangement according to the claims characterizing the invention. The invention is described in the following more in detail in connection with the accompanying drawings, where FIGURE 1 shows schematically a perspective vue partly in section of a derrick bridle suspension with a cable guide according to the invention; FIGURE 2 shows a a perspective vue partly broken away of a gui- diding element i operation; and FIGURE 3 shows a perspective side vue of the cable guide accor¬ ding to the invention. In figure 1 there is schematically shown a derrick bridle 1 of a derrick (not shown), the bridle being suspended by four pairs of cords 2-5, the cords running over pulley arrangements 6-9. A cable 10 for transmitting electricity to the various operation units of the derrick bridle 1 as well as transmitting pilot, regulation and control signals extends from the derrick (not shown) down to the derrick bridle 1 where it is collected in and lifted out of a basket on top of the derrick bridle 1 respective¬ ly, depending on if the derrick bridle is hoisted or lowered. In all these respects the execution is quite conventional. Brackets 12 extending between opposed cords 2a, 4a are fastened to these cords in a way so that the cords 2a, 4a at the far-off ends of the brackets 12 are passing freely through eyes 15. The brackets 12 have a ring 13 approximately in their centre, through which the cable 10 runs, the cable 10 comporting equally distan¬ ced spherical elements 14 which cannot penetrate any of the rings 13 with a result to be described further on. Figure 2 shows a cable guide according to the invention. The guide consists of a bracket 12 extending between two lifting cords 2a and 4a respectively and comporting a ring 13 approxima¬ tely in the centre, through which the cable 10 is running. At the far-off ends of the bracket 12 eyes 15 are situated, through which the lifting cords 2a and 4a respectively are running. The eyes 15 are shown as clamps being screwed to the respective far- off ends of the bracket 12. However, it is evident that these eyes can have any construction whatsoever, only they are keeping the bracket 12 stretched between the two cords 2a, 4a in a subs¬ tantially horisontal position without being engaged in the move¬ ment of the cords. An element 14 formed as a double cone, a sphe¬ re or any suitable form is fastened on the cable 10 with a size not to pass through the ring 13. This means that the elemnt 14 is engaged by the ring 13 when the cable 10 is hoisted, i.e. the derrick bridle being lowered, and thus the bracket guiding the cable is hoisted. Figure 3 shows the function of the cable guide. As example three embodiments 12a, 12b, 12c of the bracket are shown, it being evi¬ dent that the number of brackets possibly being more or less, but it is anyhow convenient to have one bracket 12 for every four meter of cable. These brackets 12a, 12b, 12c are arranged in the way decribed in figure 2. The ring 13a of the uppermost bracket 12a har a relatively small diameter and the element 14a has in its largest part a somewhat larger diameter than the inner diameter of the ring 13a. The double conical form of the element 14 has the advantage that the element 14 easily can be guided into the right position in the corrsponding ring 13 and can easily pass through the rings 13 lying below. Thus, the inner diameter of the ring 13b is somewhat larger than the inner diameter of the ring 13a but somewhat smal¬ ler than the inner diameter of the ring 13c. Thus, the element 14a can pass through the rings 13b and 13c, but not through the ring 13a. The element 14b on its way up from the basket 11 can pass through the ring 13c but .is stopped by the ring 13b and eng¬ ages accordingly the bracket 12b guiding the cable during persis¬ tent hoisting. The distance between the elements 14a and 14b can be any suitable distance, but is, as mentioned before, preferably about four meter. A further element (not shown) follows the ele¬ ment 14b and is stopped by the ring 13a for bringing along the bracket 12c guiding the cable. The result of this arrangement is that the cable 10 is guided by the brackets 12 in such a way that it keeps its position indepen¬ dent of its exposure to gusts. The hoisting cords 2a and 4a res¬ pectively are comparatively narrow and are tightly stretched bet¬ ween the derrick (not shown) and the heavy derrick bridle 1, with the consequence that these are not effected by gusts and also can sustain the cable 10 without being effected. According to figure 3 the cable 10 falls down into the basket 11 through the rings 13 of the brackets 12 when the derrick bridle is hoisted, and as the elements 14 are increasing in size down¬ wards from the top, as well as the inner diameter of the rings 13, the elements will fall all the way through and do not disturb the cabel 10 being assembled in the basket 11. At the same time the brackets 12 are placed on top of each other on the upper side of the basket and are stored there until the bridle 1 is lowered, when a contrary action takes place, i.e. the elements 14 are stopped by the corresponding ring 13 and are bringing along a bracket 12 one at a time from the staple of brackets on top of the basket 11. The brackets 12 as well as appertaining components are conve¬ niently made of a lightweight material, e.g. reinforced plastics or light metal. Thus, the strain on the cable 10 becomes small but is sufficient to keep the cable adequately stretched so as not to be dislocated by gusts. As one can see from the description above the problem mentioned previously is solved in an easy and efficient manner.

Claims: Claims 1. Arrangement for hoisting devices to keep a cable (10) or simi¬ lar substantially vertically stretched between a derrick or simi¬ lar and a hoisting device, e.g. a derrick bridle (1), for hand¬ ling containers, characterized in that a set of brackets (12a, 12b, 12c) is stretched between and glidably fixed to two opposed hoisting cords (2a, 4a), that the brackets (12) have a ring (13a, 13b, 13c) approximately at their centre, through which ring the cable (10) is running, that the cable (10) is equipped with a set of elements (14a, 14b) fixed to the cable (10) at a distance from each other, the elements having an increasing diameter for each element from the top downwards and that the rings (13a, 13b, 13c) on the brackets (12a, 12b, 12c) being placed on top of each other have an increasing inner diameter for each bracket from the top downwards so that each ring (13a, 13b, 13c) one by one is stop¬ ping the passage of a predetermined element (14a, 14b) to the top through the corresponding ring, whereby each element (14) at a relative hoisting of the cable (10) is lifting its corrsponding bracket ( 12) . 2. Arrangement according to claim 1, characterized in that the circumference of the corresponding rings (13) is coated with a wear material reducing the fricition. 3. Arrangement according to claim 1 and 2, characterized in that each bracket (12) with an eye (15) encircles a hoisting cord (2a, 4a) at its uttermost ends. 4. Arrangement according to claim 3, characterized in that each eye (15) is coated with or is made of a friction reducing materi¬ al.

Inventors: NIELSEN ERIK, NIELSEN, ERIK
Applicants: BROMMA CONQUIP AB
Application year: 1990
Main classification: H02G11
IPC codes: B66C13, H02G11