GB2548921A - Winch - Google Patents

Abstract

A linear winch comprises a grip box 30 with split wedges 33, 35 for gripping a cable 5 when the cable 5 is located within the grip box 30, the split wedges 33, 35 comprise two or more components, which may include a wedge component 33 and a spacer component 35 and which can be separately removed from the grip box 30 to allow an increased diameter portion 7 of cable 5 to pass through the grip box 30. A pair of split wedges 33, 35 may grip the cable 5 between them. The increased diameter portion 7 may be spelter socket or other component joining two lengths of cable 5 together. A primary actuation means may move the grip box 30 relative to a winch frame. An elevating support table (40 fig. 4a) may support the split wedge components 33, 35 outside the grip box 30. The linear winch may be a continuous liner winch with two grip boxes (30, 300 fig. 3a). Bearings 37 may be provided between the split wedge components 33, 35 and/or between the side walls of the grip box 30 and the split wedge components 33, 35.

Description

WiMCH

The present inverition relates to a iinear winch, particularly though not exclusively to a linear winch which may be used to pull a cable under load for marine pipeline applications.

The installation of pipelines in marine locations typically requires a pipeline to be pulied many hundreds or even several thousands of rrmters, for example from an onshore fabrication site to offshore, or from a lay barge offshore to an onshore wFork site. This can be carried out by the use of winches which may be sited on land or on marine structures such as barges. Linear winches, amongst other types of winch, are commonly u.sed for this purpose.

Linear winches usualiy comprise two grippers which work in a "hand to hand" fashion. The grippers may pull a cable, e.g, a wire rope, through the winch in a continuous manner or an intermittent manner. Continuous operation requires each gripper, in turn, to grip and move, pulling the cable, intermittent operation requires o.niy one of the grippers to move whilst the other Is fixed: the fixed gripper holds the cable v/hilst the moving gripper retracts, and then the moving g.dpper holds and pulls the cable whilst the fixed gripper allows the cable to pass through,

Linear winches exhibit certain advantages over other winches such as drum winches. A drurn winch winds the wire rope onto a reel or drum and as the drum becomes full the pulling power of the winch decreases, In contrast a linear winch can e;<ert the maximum pulling power at all limes and any drum or reel behind the winch, which may store the wire rope, does not need to be under significant bad. A gripper in a linear winch may comprise two wedges which are designed to grip the wire rope from opposing side.s. The wedges are suitably configured (for exarrmie by use of a profiled Insert) to fit around the particular diameter of wire rope used to carry out the pulling, and to grip said wire rope. The wedges are typically located within ss grip box, a structure which has two main purposes, Flrstiy the grip box is designed to constrain the wedges in such a manner as to withstand and direct the iongitudinai and iaterai forces during rjperation, Secondiy the grip box Is designed to allow the attachment of an actuator (lypicaliy hydraulic cyiindersi to apply a pulling load. Generally the inner side walls of the grip box are angled and cooperate with corresponding angled outer surfaces on the wedges so that longitudiriai movement of the grip box forces the wedges laterally inwards to grip the wire rope, Once engaged, the gripping force becomes a function of the pulling load applied. Generally, a set of roller bearings mourited between each of the wedges and the grip box wall allows efficient trans.mission of the ioniitudsnal load Into a lateral "grip" force.

Normally two grip boxes are utilized such that the wire rope can be pulled using each grip box in turn, the load being passed from one grip box to the other in a "hand to hand" fashion. Frequently It is the case that the load is pulled in a continuous fashion .such that the load on the wire rope is passed from one grip box to the other allowing one set of hydraulic cylinders to take up the load as another set is relieved of the load. A secondary set of hydraulic cylinders may be u.sed to assist with the engagement and release of the wedges. in some cases, the winch design may Involve an inter.mittent pulling operation In which the firisi of the two grip boxes Is msoved to pull the load, after which the second grip box is used in a static position, i.e. to rriaintain the load while the first grip box is repositioned to take up the load again. This process is continued in an Intermittent manner. A number of lengths of wire rope may be required depending on the length of the puli, individual lengths of wire rope are connected by use of mechanical means such as for example spelter sockets. It may be necessary to pass the mechanical conrteciion or socket around or through the winch which in turrr requires it to pa.ss around or through the grip box.

The passing of a socket through a winch, when under the necessary tension to pull the required ioad, is a criticai procedure, and winch operations personneJ are required to facihiate this process, for example by removing or lifting the grip box lid, removifig tiie wedges and rollers and, after the passage of the socket, reptacing the wedges, roiiers and grip box lid. St is also common to iower the grip box to allow the socket to pass. The process is repeated for the second grip box.

The present invention has resulted from research and development work carried out in order to improve on known linear winch technology and to arJdress some of the shortcomings of conventional winches.

From a first aspect the present invention provides; a linear winch for pulling a cabie, comprising: .................. - a grip box, and split wedges for gripping said cable when located within said grip box, each spilt wedge comprising two or more components which are separately removabie from said grip box to allow an increased diameter portion of said cable to pass through said grip box.

The increased diameter portion may be, for example, a fastener or socket for connecting two lengths of cabie together, or a repaired area of cable with a repair jacket. In particuiar, spelter sockets are commonly used in the pipe pulling industry to join lengths of steel wire rope together because of their reasonably compact nature, high strength and ease of handling.

The present invention allows portions of increased diameter to be passed through the linear winch in a time efficient and economical manner. This is advantageous In reducing down-time and increasing the length of pipeline which can be installed per unit time.

In p3rticuiar, in accordance with the present invention, it is not necessary to dismaniie or lower the grip box for a socket to pass: instead the socket can go through the grip box in sffo. The present invention results in less human intervention, a more strearrhined process, and fewer health and safety Issues.

The split wedge components are separately removable and replaceable from the grip box. This mear^s that they are also sequentially removable and i epiaceable, In other 'words one part of each spilt wedge may be moved out from, or back into, the grip box, before another part of said split wedge.

Because the wedges are spilt into two or more components which are removable separately, a compact design is possible. If the wedges were not split then the winch would need to be significantly longer to allow space for the wedges to be slid out from and/or back into the grip box. The compact design means that Iransportatiori costs and logistics are significantly improved and that the amount of valuable deck space required is reduced.

Convenlentiy, each grip box may comprise a pair of split 'vvedges. The wedges ritay be mirror images of each other and may grip the cable from opposite sides.

Each split 'wedge may have a truncated wiedge shape and may comprise tvy'o cori’iponents; a 'wedge con-ponent (which may also have a truncated 'wedge shape); and a spacer component in one arrangement, the grip box comprises two opposed side wails which are substantially vertical and are angled reiative to the longitudinal direction so that the distance between the two side wails is less at the front (load-facing end} of the grip box compared to the rear of the grip box. The split wedges are configured so that, in u.se, a pair of split 'wedges .substantially occupies the internal space of the grip box, gripping the cable between them, and subject to the presence of other components such as bsasings to facHtiaie the movement of the spBt wedge components.

OptionaHy, each split wedge may have a substantiaily trapetial shape when viewed from above and a sobstantiaiSy trapetiai prismatic structure overall, \with the apex of the trapesium or wedge at the front of the grip box when in a gripping position. .Such a trapezia! prismatic split wedge may comprise the foOowing components: (i) a wedge component having a substantially trapezia! prismatic shape; and (ii) a spacer component. Optionally the spacer component may be of a shape such that the wedge component and the spacer component together form a split wedge having a substantialiy trapeziai prismatic shape overall, so for example the spacer may take a substantiaily rectangular prismatic shape or a substantially paralielepiped shape, it will be appreciated, however, that such geometries are mereiy optional. The important characteristics of the split wedges and the grip box are that the split wedges fit within the grip box such that they can grip the cable, that the split wedges can be moved to be released from the cable, and that the split wedges comprise at least two component parts.

The grip box and split wedge comporsents are made from rigid, e.g, mstailic, material which is able to withstand the forces applied. in use, a cable compri.sing a spelter socket connection (or other increased diameter Item) is pidied by the winch, in order for the spelter socket to pass through a first grip box the load is taken by a second component (e.g. a second grip box) so that the split wedge components within the first gnp box are no longer required to grip the cable and can be removed from the first grip box to allow/ the spelter socket to pass through the first grip box. After the spelter socket has passed through the first grip box the split wedge components are moved back into the first grip box so that they can again grip the cable and take the load, if a second grip box is used then an analogous series of steps is carried out in relation to the .second grip box, i.e. the second sel of split wedge components are removed, the spelter socket is passed through the second grip bOK, and the split wedge ccmiponents are moved back into their locking position.

The grip boxes are movable relative to the winch frame by actuators, e,g. hydraulic cylinders. Further actuators, e,g. further hydraulic cylinders, may be used to move the split v,/edge comporsents,

The movemerst of the spilt wedge cofriponents may comprise longitudinal and lateral steps to facilitate removal and replacement In a smail amount of space. For example once the spelter socket has passed through, space constraints may mean that a wedge component is slid back Into the grip box and therj moved iateraliy sideways before a spacer component is slid back into the grip box.

The benefits of the split wedge system of the present invention can be sriore dearly understood by considering the operatlr^n of the device after the spelter socket has passed through the grip box. At this stage the wedge components need to be reinserted into the grip box and the spelter socket may block access. Access would be eased by having a greater distance between the spelter socket and the grip box, but this would rerpjire the .grip box to be able to have a longer window of possible movement relative to the wir?ch frame, which In turn would mean that the winch would be larger, instead, by splitting the wedges in accordance with the present invention it is feasible to replace the components despite the spelter socket being relatively dose to the grip box, because smaller components can be moved out of and irvto the grip box In separate stages. Therefore, by way of example, primary hydraulic cylinders with a 2m stroke may be used with apparatus having split wedge components, where otherwise it might have been necessary to use primary hydraulic cylinders with a 4m stroke. Clearly, In a winch having two grip boxes, saving 2m length per grip box resuits in a winch which may be of the order of 4m shorter, which brings significant advantages as discussed above.

LaieraS movement may also be used to move the split wedge components out of the way of the speiter socket, thereby enabling a compact design, Optionaliy, support tables may be deployed to support the split wedge components when they are moved out of the grip box. The split wedge components may then be lifted off the support tables so that they are out of the way and allow the spelter socket to pass. The split wedge components may be configured with points of attachment for lifting gear so that nn efficient handilng/ movement sequence may take place.

The support tables are particularly advantageous in contributing to the compact nature and efficient operation of the winch. They may be elevated into position automatically when required, for example hydraulically or by other means of actuation, and may be lowered and stov/ed when not in use, allowing the grip box to pass over them. This minsmi28s operator involvement within the winch frame, and therefoi"e facilitates automation, enhances the speed of operahon and safety, and minimiiiss difficulties which may occur due to human error.

The first and second grip boxes and their corresponding split wedges and adjacent components may differ slightly due to their different positions and due to constraints of the winch frame. For example, a single support table may be used behind the front grip box to support ail of the components; in contrast it may be necessary to have two Indivlduaiiy operated sub-tables behind the rear grip box because of limited space between the rear grip box and the rear part of the winch frame.

The present invention allows spelter sockets and other bulky components to be passed through a linear winch much more efficiently and in a more automated manner than has hitherto been possible. In particular the present Invention permits spelter sockets and similar components to be passed through the envelope of a grip box cavity efficiently and quickly and in such a way that the winch may be of a compact design.

The present snvenlion w55l now be described in further, nofi-ismiting detail, witSi reference to the Figures in which:

Figure 1 shows in cross-section view some key components of known sequential linear winches;

Figure 2 shows in cross-section view a split wedge in accordance with one embodiment of the present invention and how said split wedge may be moved out of a grip boK In order to allow the passing of a spelter socket;

Figure 3 shows a sequence of cross section vdews of a linear winch in accordance with the present Invention showng the passing of a spelter socket through a grip box;

Figure 4 illustrates the use of a support table in accordance with one embodiment of the present invention;

Figure 5 illustrates in perspective view some components of a linear winch in accordance with the present invention (for darity, the grip box lid is not shown in this illustration, even though It is present in accordance with the present inventiorO;

Figure 6 shows a wedge component in perspective view in accordance with tbs present invention; and

Figure 7 shows a spacer component in perspective view in accordance with the present Invention. yyith reference to Figure 1, a typical con’ventlonal continuous linear winch 1 comprises frame 3, front grip box 10 with wedge assembly 12 and rear grip box 20 with wedge assembly 22, The grip boxes 10, 20 and wedge assemblies 12, 22 sequentially grip and puli on a steel wire rope 5 that is connected to a load to be moved. The movement of the grip boxes 10, 20 is controlled by hydraijilc tscluators 16, 25, Wedge essemb:ie,s 12 and 22 each comprise two half wedges, one on either side of the wire 5. It can be .seen that the interfaces 14, 24 between the grip boxes 10, 20 and the wedges 12, 22 are angled so that as a load is applied the longitudinal force Is translated into a lateral inward force to enhance the gripping of the wire S by wedges 12, 22. Spelter socket 7 is also shown in figure 1. Such winches may typically provide a pulling power of lOOt to SOOt and are typically several meters long.

As shown in Figure 2a, the wedge assemblies of the present invention differ from conventional wedge assemblies in that they are split into separate components. Figure 2a Is similar to part of Figure 1 in that It shows half a grip box 30 with an angled interface 34 between the grip box 30 and the wedge assembly, and in that It shows wire S arid spelter connection 7, Figure 2a however differs from figure 1 in that the wedge as.sembiy is a split wedge comprising wedge component 33 and spacer component 35, Figure 2a aiso shows bearings 37 between wedge component 33 and spacer component 35, Further bearings (not shown) may aiso be present, for example at interface 34.

Figure.s 2a to 2f show a possible sequence In accordance with the present invention. Figure 2a shows the components in position as the spelter socket approaches the grip box. Figure 2b shows the arrangement svith the split wedge having been removed. Figure 2c shows the arrangement ‘with the spelter socket having passed through the grip box. Figure 2el illustrates how wedge component 33 may be reinserted into the grip box by longitudinal movement followed by lateral movement. Figure 2e illustrates the arrangement after spacer component 35 has been reinserted, Figure 2f fliuslrates the arrangement after the load has been re-applied which causes wedge component 33 to move lorigitudinaliy and then to transmit a gripping force laterally.

Hgure 3 shows a possible sequence of steps and posiuosis of components within the linesr winch In accordance with an embodirsient of the present Invention. This illustrates the passing of a spelter socket 7 through a front grip box 30. Figure 3a shows the configuration of the apparatus after the front grip box 30 has pulled the cable 5 to the right. At this stage the bad Is transferred to rear grip box SCO. Wedge components S3 and spacer components 3f> are moved out of the front grip box 30, cptionaNy by hydraulic actuation means Inot shown) to result in the configuration shown in figure 3b, Components 33; 33 are removed {figure 3c). Rear grip box 300 then moves to its extended position, pulling the bad and pulling spelter socket 7 into the envelope of front grip box 3u (figure 3d), Front grip box 30 retracts, allowing spelter socket 7 to dear (figure 3e). Mow that spelter socket 7 has pa,ssed through front grip box 30, spilt wedge components 33, 35 can be reinserted. Wedge components 33 are loaded back onto the winch (figure 3f), pulled back into front grip box 30, optionally by longitudinal actuation means (not shown) (figure 3g), and centered, optionally by lateral actuation means (not shown) (figure 3h). Spacer components 35 are loaded back onto the winch (figure 3i) and moved back into front grip box 30, optionally by actuation means (not shown). This results in front grip box 30 comprising split wedge components 33, 35 which is able to taka the load (figure 3j), Front grip box 30 then extends. Cabie 5 and spelter socket 7 are then able to advance to the configuration shown in figure 3k, A further series of steps then occurs matatss rmstandi (not shown) resulting in the pa.ssing of the spelter socket 7 through the rear grip box 300,

With reference to Figure 4a a support table 40 may be elevated so as to be aligned with grip box 30 such that spilt wedge components 33, 35 may be moved out of grip box 30 onto support table 40. As Illustrated in Figure 4b, split wedge components 33, 35 may be moved out of the grip box 30 by hydraulic actuation means 50 and accordingiy split wedge components 33, 35 may have attachment means 55 for attachment to said hydraulic actuation means 50.

After the speiter socket 7 hss passed through the grip box 30 wedge component 33 ojay be pieced back on the support table and may then be slid back into the grip box longitudinally and then moved iaterally (in the direction of the arrow in Figure 5) and subsequently spacer component 35 may be slid back into place, in Figure 5 the lid of the grip box is not shown merf-iy for the purpose of clarity. It is however present

With reference to Figure 6,, wedge component 33 typically comprises groove 5S with insert 59 which is interchangeable to allow for different diameter ropes and cables to be gripped, and may contain means of attachment 55 for attaching actuation means, and/or further means of attachment 57 for allowing the lifting of the wedge component 33 out of the wirsch frame.

With reference to Figure 7, spacer component 35 may comprise attachment means or lifting means (not shown} and linear bearings 62 may be used to facilitate movement of the wedge component 33. in one embodiment, the linear winch of the present invention has the following characteristics, ft may grip wire of diameter 76mm to 127mm and may permit the passing of sockets manufactured to suit wire ropes of those sites and other such wire rope terminations or attachments of similar size. Loads of up to 800 tonnes may be pulled. The line speed may be between 1 and 5 m/minute. The linear winch dimensions may be 15,8 m |l| x 3.1 m {W) x 1.7 m IH), it will be appreciated that these specifications relate to a specific product and may be varied. For example, optionally the linear winch frame length may be between 10 and 20 m, the width between 2,5 and 3.5 m and the height between 1 and 2 m; optionally the winch may be used with wire rope diameters of between 50 mm and 150 mm; and optionally the spelter sockets and other such wire rope terminations or attachments may be sized so as to suit wire rope sizes up to 150 mm diameter.

Claims (1)

1. CLAIMS A Hrsesr for puNing a cabio, oorripriiirsg: a grip box., and split wedge’s far gripping said cable v^'hen located within said grip box, each xplit wedge comprising two or inors cornponecits which are separately removable from said grip box to allow an increased diameter portion of said cable to pass through said grip box. A liriear winch as ciaimed in claim 1 wherein said increased diameter portion is a spelter socket or other component Joining two iengths of cable together, A linear winch as claimed in claim 1 or claim 2 wherein said grip box comprises a pair of split wedges for gripping said cable between them, A linear winch as daimsd in any preceding claim wherein each split wedge comprises a wedge component and a spacer component. A linear winch as claimed in any preceding claim wherein each split wedge has a substantially trapetlal prismatic structure. A linear winch as claimed in any preceding claim further comprising primary hydraulic actuation means for moving said grip box relative to the windvframe, A linear winch as claimed in any preceding claim further comprising secondary and/ or tertiary hydraulic actuation means for moving said split wedge components out from and/ or into said grip box. A linear winch as claimed in any preceding claim further comprising a support table which may be elevated to support said split wedge components when they are removed from said grip box, and which may be lowered to be stowed v>/hen not in use. A linear winch as dairned in sny preceding claim further comprising bearings or roHetrs between the split wedge components and/ or between the split wedge and the grip box side walls and/or on the base of the split wedge components, A linear winch as claimed in claim 9 wherein one or more bearing assembly or roller assembly is present on, attached to, or integral with, one or more of the split wedge coniponents, ,A linear winch as claimed in any preceding claim comprising two grip boxes and corresponding split wedges. A linear winch as claimed in claim 11 which is a continuous linear winch, A split wedge or grip box suitable for use in a linear winch of any preceding dairn. Use of a linear winch according to any of claims 1 to 12 for pulling a load. Use as claimed in claim 14 In a method of installirrg a pipeline.