GB2353305A

GB2353305A - Plough with vibrating member positioned forward of the share

Info

Publication number: GB2353305A
Application number: GB0018053A
Authority: GB
Inventors: Timothy William Grinsted
Original assignee: Engineering Business Ltd
Current assignee: Engineering Business Ltd
Priority date: 1999-07-22
Filing date: 2000-07-24
Publication date: 2001-02-21
Anticipated expiration: 2020-07-24
Also published as: GB2353305B; GB0018053D0; GB9917143D0

Abstract

A plough for use in the burial of cables or pipelines in the sea bed includes a share and a soil engaging device [22], which is adapted to vibrate, positioned forward of the share. In one embodiment, the soil engaging device [22] is mounted on resilient supports [23], which may be rubber bushes. The soil engaging device [22] may also be mounted on a yielding support which allows it to move if it is subjected to overloading.

Description

2353305 Improvements to Ploughs This invention relates to ploughs,

particularly those used to bury cable or pipe in the bed of the sea or other water.

Ploughs are well-known for use in protecting cable and pipelines underwater. The cables or pipelines are buried to protect them from damage by, for example, fishing equipment or anchors. Typically these ploughs are towed via a towrope by a vessel on the surface of the water, but may be towed by an underwater tractor. Such ploughs are fitted with a soil-engaging share that is shaped to dig into the seabed under the action of the towing force and produce a trench that the cable or pipe is placed into. The ploughs usually lay the cable or pipeline in the trench. The invention applies to all types of plough.

Hitherto, these ploughs have been operated successfully in many types of seabed and over great distances, but sometimes experience problems if hard seabed, rock, or certain types of sand or silt seabed is encountered. Under these circumstances the plough fails to bury the cable or pipe to the required depth to protect it. This can be a serious disadvantage resulting in a high risk of damage to the cable or pipe.

There is a known method of using a powered means to vibrate or oscillate the soilengaging ploughshare. This, under the correct circumstances, results in a reduction in the force required to pull the plough or an increase in the depth the plough penetrates the soil. This method of reducing pull has been applied to ploughs for operation on land and on the seabed. These designs do, however, suffer some disadvantages in relation to use on seabed ploughs. In particular, the share of a subsea plough makes up a substantial part of the plough weight, and so it is difficult to make this vibrate rather than the remainder of the plough. It is an object of the current invention to improve and make more effective the method of applying vibration to the soil.

According to the invention there is provided a plough comprising a first share, a soil engaging device positioned forward of the first share which is adapted to vibrate.

Preferably the first share is the main share of the plough.

Preferably the soil engaging device comprises a cutting blade, Preferably the soil engaging device comprises a share. 10 Preferably the soil engaging device is mounted to one or more resilient supports. One or more of these may be rubber brushes.

Preferably the soil engaging device is mounted to a share. 15 Preferably the soil engaging device is mounted to a chassis of the plough.

Preferably the soil engaging device is vibrated by a vibrating mechanism within it or mounted on the plough.

Preferably the soil engaging device is mounted to a yielding support, allowing it to move, if subject to overloading. The yielding support may be a resiliently based mount, for example a pivot.

Thus, a pipeline or cable plough is provided with a powered vibrating or oscillating soil engaging device that is positioned forward of the main plough share. The vibrating device may be a soil cutting blade mounted on resilient supports on the plough chassis or share. The vibrating device may be mounted on a yielding support, allowing it to move back, if subjected to overloading. The vibrating device may be 30 movable to a stowed position out of the soil if it is not required.

2 The plough of the invention can be used in trenching and in laying pipeline or cable.

Any reference to the term "soil" should be interpreted as meaning any material to be ploughed including, but not limited to, earth, mud, shale, sand and in certain circumstance, rock.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:

Figure I shows a plan view of a plough of a conventional type.

Figure 2 shows an elevation of the plough shown in Figure 1. Figure 3 shows an elevation of a plough according to the invention.

Referring to Figures I and 2, a seabed cable plough of a conventional type is made up of a chassis 1, a share 3, and support skids (2 and 4). The front skids 2 support the plough on the seabed 6 and the share 3 penetrates the seabed as the plough is towed by a ship (not shown) via towrope 5. The front skids 2 are adjustable hydraulically to set the trenching depth of the plough. Cable 7 enters the plough at bellmouth 12 and exits underground at the back of the plough 8. Rear skids 4 support the back of the plough when operating in very soft seabed soils. The plough may be fitted with a control and monitoring system and a hydraulic power pack, allowing the operators on the ship to operate it effectively.

Referring to Figure 3, a cable plough according to the invention is similar to that shown in Figures I and 2, and is fitted with a vibrating soil engaging assembly 22.

The vibrating assembly 22 is mounted on one or more resilient supports 23 and is powered by an oscillating mechanism within it or mounted nearby on the plough. The oscillating mechanism, which may effect linear, rotating or any other repeated motion, is powered by a hydraulic or electrical system on the plough or mounted remotely, for example on a ship. The oscillating mechanism can consist of a set of out of balance rotating weights, a piston or two wheels geared together carrying weights or any other method known to those skilled in this field.

3 The vibrating assembly engages the soil and vibrates it in advance of the soil coming into contact with the main plough share 3. In this way, the soil can be loosened or otherwise rendered easier to plough. In this embodiment the vibrating soil engaging assembly is a soil cutting blade such as a plough share. Because of the resilient support bushes 23 and the lesser weight of the auxiliary share 22 compared to the main share 3 and to the plough 1 itself, vibration of the remainder of the plough is kept to a minimum.

The resilient supports are typically rubber bushes and are used to mount the vibrating auxiliary share to the chassis of the plough. The resilient supports allow some of the vibration energy to be dissipated rather than being transmitted to the rest of the plough. Alternatively, the vibrating assembly could be mounted using resilient supports to an auxiliary share. The vibrating soil engaging assembly is typically mounted on a yielding support, for example, the rubber bushes may also be pivotable and adapted by the provision of a spring or other resilient means, to allow the assembly to pivot out of the way if it is subjected to overloading. A yielding support separate from the resilient supports can also be used.

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Claims

1. A plough comprising:

a first share; a soil engaging device positioned forward of the first share when ploughing which is adapted to vibrate.

2. A plough according to Claim 1 in which the first share is the main share of the plough.

3. A plough according to Claim 1 or 2 in which the soil engaging device comprises a soil cutting blade.

4. A plough according to Claim 3 in which the soil engaging device comprises a share.

5. A plough according to any preceding claim in which the soil engaging device is mounted to one or more resilient supports.

6. A plough according to Claim 5 in which the soil engaging device is mounted on one or more rubber bushes.

7. A plough according to any preceding claim in which the soil engaging device is mounted to a chassis of the plough.

8. A plough according to any of Claims 1 to 6 in which the soil engaging device is mounted to a share.

9. A plough according to any preceding claim in which the soil engaging device is vibrated by a vibrating mechanism within it or mounted on a main portion of the plough.

10. A plough according to any preceding claim in which the soil engaging device is mounted to a yielding support allowing it move if subject to overloading.

11. A plough according to Claim 10 in which the yielding support comprises one or more resiliently biased mounts. 10

12. A plough substantially as described herein with reference to and/or as illustrated in Figure 3.

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