GB2212536A

GB2212536A - A cable plough

Info

Publication number: GB2212536A
Application number: GB8826703A
Authority: GB
Inventors: Wolfgang Giebel; Klaus Pichler; Dieter Kunze
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1987-11-17
Filing date: 1988-11-15
Publication date: 1989-07-26
Anticipated expiration: 2008-11-15
Also published as: AU603269B2; IN170120B; GB8826792D0; GB2212536B; DE3739041A1; AU2561488A

Description

"A CABLE PLOUW The invention relates to a cable plough for the laying of a

cable in the ground, in particular at the bottom of a body of water, and to methods of laying cables underwater using such a cable plough.

Many forms of cable plough for the laying of cables in the ground are known, although such devices operate within view and at a distance such that control and guidance during operation can be carried out directly manually. It is also known to arrange cable ploughs on skids so that they can be drawn across the land. Such devices can then also be used underwater, although considerable difficulties with regard to control and guidance occur, in particular when a complete underwater installation is required. Difficulties arise as soon as the device is used, since generally a lack of knowledge of characteristics of the ground gives rise to problems in stabilising and aligning the device.

The object of the present invention is to provide a cable plough which is controllable for the underwater laying of cables, where the cable which is to be laid is to be embedded in the bed of a body of water.

According to the invention, there is Provided a cable plough for laying cables in the ground, in particular in the bed of a body of water, comprising ploughing and cable-laYing devices carried on at least one floodable float body.

One of the advantages of the cable plough of the invention is that this cable plough can be fully used underwater and all functions can be remotely controlled. Thus, the cable plough according to the 2212536 invention can be floated and submerged, these functions also being controllable. This opens up the possibility that the cable plough of the invention can be submerged into the body of water in a controlled fashion at the desired location and then be raised again without the need to use expensive cranes or other lifting equipment. This widens the possibilities of use and simplifies the operating procedures. Furthermore, the cable plough according to the invention can be provided with a plurality of remote controllable devices which permit a fully automated laying procedure underwater which will be explained in detail below with reference to the drawings. Moreover, it is possible, by selecting the supply of the cable to be laid in accordance with the cable plough, to adopt the most expedient procedure to the particular application.

The invention will now be explained in detail with reference to the drawings, in which:

Figure 1 is a side view of a cable plough according to the invention; E the cable plough of Figure 1; Figure 2 is a front view o.

Figure 3 is a plan view of the cable plough of Figures 1 and 2; Figure 4 is a control diagram of the regulating units for the float behaviour of the cable plough; Figure 5 is a side view of a supply unit for the cable which is to be laid; Figure 6 is a diagrammatic side view to illustrate a laying operation with the cable supplied along the traction rope for the cable plough; and Figure 7 is a similar view to that of Figure 6 to illustrate a second laying operation with the cable supplied separately from the traction rope.

Figure 1 shows a cable plough according to the invention. From this view, it can be seen that the actual cable plough, comprising its ploughing and laying devices 18 and 19, and the associated control and regulating units, is arranged on a float body 1,2 3. This float body consists of a plurality of float chambers 1, 2 and 3 which are assembled in a doubled design symmetrically-about a central axis, for example, in an arrangement similar to that of a dinghy. The corresponding float chambers on either side of the axis are identical in shape and, depending upon requirements and the operating procedure, can be flooded and then emptied again. The control functions for these individual float chambers are preferably independent of one another, in particular with regard to the flooding procedures, and therefore as a result of this separate control the submerged behaviour of the cable plough in the case of underwater use can be regulated accordingly. In this way, a cable plough according to the invention can be used at any location of a body of water and by regulated flooding of the individual float chambers 1, 2 and 3 can be purposively and reliably submerged. The flooding for the submergence procedure and also the emptying of the float chambers for resurfacing are carried out through inlet openings 4 and 4 - corresponding outlet openings 5 in the individual float chambers 1, 2, 3. The inlet openings 4 are connected to preferably remote controlled magnetic valves either through corresponding pressure lines or directly. The outlet openings 5 are preferably provided with lattice-shaped covers to prevent the passage of foreign bodies. The cable plough is provided vith carrying or pulling lugs 10 by means of which it can be transported or, in operation, can be pulled from the cable-laying ship by means of a pulling rope. Normally, however, the cable plough is suspended from a pulling shaft 14 by a pulling rope attached to the cable-laying ship. This pulling shaft 14 is in principle rotatablY attached to the cable plough, but the possbility of rotating is stopped, for example, by a control unit, for example, a piston or a lifting cylinder 15, so that a straight course of the cable plough is ensured. In special applications, such as, for example, in areas subject to earth movements, it is desirable to lay the cable with a so-called "cable length plus" so that in the event of any changes occurring in the ground, a compensation of length can take place by virtue of the laid "cable length plus". In this way the destruction of the cable can be avoided. In this case, the above-described "cable length plus" is provided in the horizontal plane. By controlled lifting movements of the lifting cylinder 15 the cable plough is moved onwards in an undulating line and thus results in an excess length of laid cable. In the event of any later tension stress to the cable, the cable laid in the form of an undulating line is stretched in its laid shape, but destruction as a result of the exceeding of the permissible tension forces cannot 1 i occur. However, it can also be advantageous to provide such a "cable length plus" in the vertical plane in which case such a procedure is carried out using a similarly controllable lifting cylinder 13. By moving the ploughing and cable laying devices up and down the "cable length plus" is then produced in the vertical plane. This is carried out using the lifting cylinder 13 with which the ploughing and laying unit 18, 19 is also normally lifted and lowered. Thus, for example, during transportation, the ploughing and laying devices 18,19 are always maintained in the raised position, so that the plough blade 18 and the cable laying guide 19 are not damaged, as indicated by the broken lines in Figure 1. In the operating state, which is shown in solid lines in Figure 1, the plough blade 18 and the cable laying guide 19 project downwards beyond the float body 1,2,3, which is provided on its underside with skids 7, 8, and are extended to the required laying depth. At the top, the cable laying guide 19 is provided with an insertion funnel 22 for the insertion of the cable to be laid. The supporting frame 21, which is mounted so as to be rotatable at one end, is raised and lowered by the lifting cylinder 13. The ploughing and laying devices 18,19 which are mounted so as to be rotatable about the axis 23 are thereby likewise raised and lowered. if, during the laying operation, the plough blade 18 strikes against an obstacle, the blade moves backwards turning about an axis 23, so that the entire plough does not remain suspended from this obstacle and the laying process can continue without disturbance. Depending upon the size of the obstacle, the plough blade 18 will move backwards to a greater or lesser extent whereby the laying depth of the cable changes accordingly in this region. However, in normal operation the plough blade 18 must be pressed into the ground with appropriate force to maintain the necessary laying depth for the cable. This necessary counter-force is applied through a spring or through a controllable pressure cylinder 20 so that this procedure is likewise controllable and if necessary can also be regulated by remote-control. Figure 1 also shows an additional float body 11 which, by means of an appropriate linkage structure 12 with the other float body 1,2,3, is arranged centrally over the other s. Such a float body 11 greatly improves the float device component and operating stability since, when it is correctly aligned relative - of the cable plough and the size of the float body 11, to the weight overall a swing body is as it were provided which can substantially reduce the risk of overturning. It can also be seen from Figure 1, that the cable plough is equipped with a:camera and a searchlight 16 which can preferably be controlled as regards direction, so that by remote transmission and remote control the operation of the cable plough on the bed of the water can be tracked.

It should also be noted that the movement behaviour of the cable plough can be influenced by varying degrees of flooding of the individual float chambers 1, 2, 3. Thus, even in the event of obstacles or the rise or fall of the bed of the water, the cable plough can easily be manoeuvred by deliberately changing the buoyancy by different degrees of flooding of the float chambers 1, 2, 3, in particular when remote observation by camera is possible.

c 7 The supply of cable to the cable plough can take place either parallel to the pulling rope using corresponding guides or by way of a separate pulling guide. However, it is also possible to carry a cable drum on which the cable is wound in the necessary length. The floodable float bodies also make possible an intermediate surfacing, for example, for the possible splicing attachment of further cable lengths.

Figure 2 is a front view of the cable plough according to the invention which shows particularly clearly how the additional float body 11 can be considered to represent a swing arrangement above the overall arrangement. This leads to a favourable stabilisation which prevents lateral tipping over on the principle of an inverted "tumbler doll". The corresponding constructional units have only been sketched in, as they are not of decisive importance in the illustration of the float body with the front float chamber 3. However, the lateral lifting arrangement from the pulling shaft 14 to the lifting cylinder 15 can be seen, by which the lateral "rolling" of the overall arrangement for the installation of "cable length plus" can be achieved. Also shown are the skids 8 which are arranged on the underside and which are additionally inclined forwards. The two arrows at the end of the plough blade 18 are intended to indicate that the blade can be rotated laterally about its vertical axis. In this way the most favourable setting angle for the plough blade 18 can be achieved, which is dependent upon the particular laying conditions. This function can also be automated by an appropriately controlled lifting cylinder and thus also remotely controlled, in which case the cable plough can also be moved on in the form of an undulating line and the laying of "cable length plus" referred to above can take place in the horizontal plane.

Fig. 3 now clarifies the previous description as it indicates how the actual plough and installation devices, with their insertion funnel 22 for the cable (visible here), are arranged between the _float chambers which are coupled together like a dinghy. The spread-out arrangement of the float chambers la, 2a, 3, 2a, 2b provides the stability which ensures reliable operation. Also shown here is the deflecting device for the pulling shaft 14. By an appropriate actuation of the lifting cylinder 15, the end of the pulling shaft 14 is moved to the side as appropriate via the angled linkage device, so that a lateral displacement of the cable plough and thus also of the plough blade 18 takes place. Thus a "cable is length plus" is laid in the horizontal direction, as already described above. The double arrow indicates the deflection direction of the pulling shaft 14 with an appropriate control of the lifting cylinder 15. a flow plan for the control of Figure 4 shows an example o magnetic valves MV which lead to the inlet openings 4 of the float chambers la, 2a, 3, lb, 2b. It can be seen that, for example, two inlet openings 4 and thus in each case two magnetic valves MV are arranged in each float chamber, as illustrated by the drawing of the overall float body. The magnetic valves MV which are shown above can either be arranged directly on the inlet openings 4 or in a separate and impervious distributor box 17. Accordingly either individual x c supply lines for the compressed air or only short connecting elements with a single central supply line are required. Depending upon the desired operating step, each float chamber can now be flooded or emptied individually or in groups through the control device STE which consists of a contact panel KF and comprises appropriately assigned switches MS 1 to 10 and MS 1,2 to 9,10. In this way, in co-operation with various other display and measurement devices, such as, for example, depth gauges, manometers, flow meters, cable length indicators and locating devices, the fully automated process of laying a cable on the bed of a body of water can be carried out and controlled, Thus, as also shown in Figure 4, the compressed air produced by a compressed air generator DL is fed through a non-return valve RV to an air chamber WK from which, through a group valve MV12, the compressed air is distributed between the magnetic valves MV 1 to 10 of the inlet openings 4. The discharge of the compressed air from the individual float chambers, which must take place on surfacing, is carried out through an outflow valve AL, where, again, individual flooding or emptying of the float chambers can take place, as required in accordance with the operation. This example is representative of any other control devices known per ge; it merely indicates that the floating behaviour, and thus the movement of the entire arrangement in the water, can be influenced by the arrangement according to the invention of individual float chambers which can be flooded and emptied separately. In particular, the trimming of the device in respect of the transverse and longitudinal axes can thereby be performed. When a corresponding control device is provided this procedure can also be automated.

However the device can also be controlled by a drive means, preferably a screw propeller which is appropriately pivotally mounted so that, when it is rotated, a corresponding alignment can at the same time be provided. The alignment can be remotely controlled and can be effected by a pneumatic adjusting device. This screw propeller can be driven by a motor or pneumatically, for example, by compressed air since the latter must anyhow be provided for flooding the float chambers.

Various methods can be selected for supplying the cable to be laid to the cable plough. Two of many possible methods will now be explained in detail. method For the supply of the cable 27 to be laid, the firs'. uses, as a reference help, the pulling rope 28 with which the cable plough 3,1 is drawn along the bottom of the water by the cable-laying ship 29, as can be seen in detail in Figure 6. As the danger exists that the cable 27 wIll become entangled with the pulling rope 28, it must be ensured that both are guided at a non-critical distance from one another. For this purpose, so-called floatable supporting buoys 24 are used for example, one of which is illustrated in Figure 5. It consists of a float body on which a guide 25 for the cable 27 is arranged. By way of a spacing rope, this supporting buoy 24 is then attached to the pulling rope 28 by means of a clamping body 26. The buoyancy of the float body of the supporting buoy 24 ensures that the cable 27 is maintained at the selected distance. A large number of such supporting buoys 24 are then attached along the traction rope 28 and thus allow the cable 27 to be supplied to the cable plough 32 and - 11 to the insertion funnel 22 arranged at the same point. The cable plough 32, with its blade 18, cuts a corresponding trench 33 as it is moved along and simultaneously introduces the cable through the cable installation guide 19. In this method a boat 30 is additionally provided for the supply of the supply lines 31. However, this too need only be provided if required and the possibility also exists of assigning the supply lines to the pulling rope.

Figure 7 is a diagram illustrating a second possibility for supplying the cable 27 to be laid. In this case, the cable 27 is supplied by way of a deflecting device 36 carried by a boat 30 to the cable plough 32, either directly or - as shown - by way of a second deflecting device 35 which is pulled along separately with the pulling rope 28. The cable plough 32 is either pulled along by the same pulling rope 28, is moved along under self or remote control, or is pulled along by a second pulling cable.

It will be apparent that there are many possible variations in the cablelaying methods described which can be selected and combined to achieve the possibilities opened by the use of the cable plough of the invention.

Claims

1. A cable plough for laying cables in the ground, in particular in the bed of a body of water, comprising ploughing and cable-laying devices carried on at least one floodable float body.

2. A cable plough as claimed in Claim 1, wherein the float body comprises a plurality of independent float chambers.

3. A cable plough as claimed in Claim 1 or Claim 2, wherein the individual float chambers have mutually independent inlet openings and outlet openings.

4. A cable plough as claimed in Claim 3, wherein at least the inlet openings are provided with respective controllable valves for the introduction of compressed air.

5. A cable plough as claimed in Claim 3, wherein the inlet openings are connected to compressed air lines having valves.

6. A cable plough as claimed in any one of Claims 3 to 5, wherein the outlet openings are covered by lattices.

7. A cable plough as claimed in any one of the preceding Claims, wherein the individual float chambers are arranged approximately in the shape of a dinghy and that the ploughing and cable laying devices are arranged between the longitudinally arranged float chambers.

8. A cable plough as claimed in any one of the preceding Claims, wherein an additional float body is arranged centrally and above the ploughing and cable laying devices.

9. A cable plough as claimed in any one of the preceding Claims, wherein the underside of the float body is provided with skids.

10. A cable plough as claimed in any one of the preceding Claims, wherein pulling and supporting lugs are provided on the float body.

11. A cable plough as claimed in any one of the preceding Claims, provided with a pulling shaft for the attachment of a pulley rope.

12. A cable plough as claimed in Claim 11, wherein said pulley shaft can be deflected laterally.

13. A cable plough as claimed in Claim 12, wherein a controllable adjusting device is provided for deflecting the pulling shaft.

14. A cable plough as.claimed in Claim 13, wherein said adjusting device is a lifting cylinder.

15. A cable plough as claimed in any one of the preceding Claims, wherein the ploughing and cable laying devices basically consist of a plough blade, a cable laying guide, and an insertion funnel for the cable to be laid.

16. A cable plough as claimed in any one of the preceding Claims, wherein the ploughing and cable-laying devices are attached to a pivot arm which is rotatably mounted at one end, and that the plough blade which is rotatably mounted on the pivot arm is vertically adjustable by means of a controllable adjusting device.

17. A cable plough as claimed in Claim 16, wherein said controllable adjusting device is a lifting cylinder.

18. A cable plough as claimed in any one of the preceding Claims, wherein at least one drive means is provided.

19. A cable plough as claimed in Claim 18, wherein said drive means is a motor-driven, or pneumatically driven screw propeller.

- 14

20. A cable plough as claimed in Claim 19, wherein said screw propeller is rotatably mounted for changes in position of the overall arrangement.

21. A cable plough as claimed in Claim 20, wherein the alignment of the screw propeller can be remotely controlled.

22. A cable plough as claimed in Claim 20 or Claim 21, wherein a pneumatic adjusting device is provided for the alignment of the screw propeller.

23. A cable plough as claimed in any one of the preceding Claims, provided with display devices for determining its location at any instant, particularly depth gauges and manometers.

24. A cable plough as claimed in any one of the preceding Claims, provided with an underater camera and a searchlight.

25. A cable plough as claimed in Claim 24, wherein the camera and the searchlight can be remotely controlled.

26. A cable plough as claimed in any one of the preceding Claims, provided with a cable length measuring device.

27. A cable plough as claimed in any one of the preceding Claims, provided with a flow meter.

28. A cable plough as claimed in any one of the preceding Claims, wherein a locating means or parts thereof is provided for determining the location.

29. A cable plough as claimed in Claim 4 or any one of Claims 5 to 28 as dependent thereon, wherein said controllable valves are arranged in a pressure-tight housing on the float body, and compressed air tubes are provided leading from the valves to the inlet openings of the float chambers.

t - is -

30. A cable plough as claimed in any one of the preceding Claims, provided with a supply line for the supply of compressed air to said chambers from a remotely located source.

31. A cable plough as claimed in any one of the preceding Claims, provided with at least one controllable outlet valve for the float chambers.

32. A cable plough as claimed in any one of the preceding Claims, provided with a remote control unit for the control of all functions.

33. A cable plough as claimed in Claim 32, provided with a device for alternating the control procedures, in particular for trimming along the transverse and longitudinal axes.

34. A cable plough substantially as hereinbefore described with reference to and as shown in Figures 1 to 4 of the drawings.

35. A method of operating a cable plough as claimed in any one of the preceding Claims to lay a cable at the bed of a body of water, wherein.the cable plough is coupled to a pulling rope of a cable-laying ship, the electrical and pneumatic supply and control lines are connected to the appropriate elements of the cable plough the cable to be laid is guided along the pulling rope in guides carried by floatable supporting buoys to the cable plough, the supporting buoys being attached to the pulling rope at spaced intervals and floating above it, and the cable is inserted by means of the ploughing and installation devices of the cable plough into trenqh in the water bed ploughed by the plough blade.

36. A method of operating a cable plough as claimed in one of the Claims 1 to 30 to lay a cable in the bed of a body of water, wherein the supply of the cable to be laid is effected independently of the pulling rope by way of a separate deflecting device which is preferably carried by an accompanying boat, and is supplied to the cable insertion funnel of the. cable plough, the cable is inserted into the ploughed trench through the cable installation guide arranged on the plough blade, the cable plough is moved along by a cable-laying ship either under remote control or through a pulling 10 rope

37. A method of operating a cable plough to lay a cable in the bed of a body of water, substantially as hereinbefore described with reference to Figures 5, 6 and 7 of the drawings.

Published 1989 at The Patent Office, StateHouse, 66'71 High Holborr-, LondonWClR4TP.FUrther copies mkv be obtained from The Patent office, Sales Branch. St Mary Crky. Orpington. Kent BR.5 3RI)_ printed by Mu- 1tipley tecbniques ltd. St Mary Crky. Kent. Con 1'87 1k