GB2166483A

GB2166483A - A clamp

Info

Publication number: GB2166483A
Application number: GB08425607A
Authority: GB
Inventors: Douglas Macfarlane; Robert Langley; Alan Anthony Rochowski
Original assignee: BRITISH UNDERWATER ENGINEERING
Current assignee: BRITISH UNDERWATER ENGINEERING
Priority date: 1984-10-10
Filing date: 1984-10-10
Publication date: 1986-05-08

Abstract

The clamp (4) is used to connect a strap or web (3) to a rope (1) and comprises two shaped parts (5, 5') connected at one end (6, 6') to form a hinge (7). In use, the other ends (8, 8') of the shaped parts (5, 5') are overlapped to form an aperture through which a locking pin (9) is passed. Thus the clamp is clamped to the rope (1) and locates the strap (3) around the rope (1). Tensile loads in the strap (3) are transmitted directly to the rope (1), not to the clamp (4). <IMAGE>

Description

SPECIFICATION A clamp The present invention relates to a clamp for connecting a first elongate flexible member to a second elongate member, particularly but not exclusively for connecting vertical straps to horizontal ropes of containment or barrier nets.

It is known to protect the marine risers of an offshore production platform from damage by drifting vessels by means of a net. The net is constructed from parallel horizontal ropes joined by vertical web straps. As the breaking loads of the ropes and the straps is in the order of 220 tonnes and 40 tonnes respectively, a substantial connection between the ropes and the straps is required.

The invention provides a clamp as claimed

in claim 1.

Embodiments of the invention will now be described with reference to the accompanying drawings, wherein: Figure 1 is a front view of a containment or barrier net; Figure 2 is an end view of a clamp in accordance with the invention connecting a strap to a rope; Figure 3 is a plan view of the clamp of Fig.

2; Figure 4 is a side view of the clamp of Fig.

2; Figure 5 is an underside view of the clamp of Fig. 2; Figure 6 is an end view of a clamp similar to Fig. 2 wherein the strap is detachably held.

In Fig. 1, a typical containment net comprises a plurality of horizontal ropes 1 extending between end posts 2. The ropes 1 are connected to each other by vertical straps or webs 3.

In Figs. 2 to 5 a clamp 4 comprises first and second shaped members 5, 5' shaped to extend around the ropes 1. As can be seen more particularly from Figs. 2 and 4, the shaped members are formed as substantially rectangular frames curved at right angles to the plane of the rectangle. At one end 6, 6', the shaped members 5, 5' are interlocked to form a hinge 7.

At the other end 8, 8' the shaped members 5, 5' are shaped so that they may be overlapped as shown in Figs. 2 and 5 so as to define an aperture to accommodate a locking pin 9. In this position the shaped members 5, 5' bite into the surface of the rope 1 so that the clamp 4 cannot be moved along the rope 1.

The strap 3 passes around the rope 1, beneath the ends 6, 6' forming the hinge 7 and beneath the ends 8, 8' of the shaped members 5, 5'. Thus the strap 3 transmits its load directly onto the rope. The clamp 4 merely locates the strap 3 in the correct position on the rope. The clamp 4 also locates the strap 3 on the rope 1 with the optimum shape. The clamp does not transmit any of the tensile loads as the load path is directly through the strap loop and into the rope 1.

To aid the "digging-in" action of the clamp 4 on the rope 1, the rope is constructed preferably of parallel fibres and is provided with a plastics coating (e.g. a hard polyurethane material) over e.g. 3mm diameter of the rope.

Such a rope has a considerable resistance to the crushing action of the loop stresses generated by the clamp 4. An example of such a rope is ICI Parafil (R.T.M.).

The clamp itself, i.e. the shaped members 5, 5', may be made of any suitable material, e.g. metal rod, wire or strip, or plastics material.

As can be seen from Fig. 6, the clamp 4 can be used to locate detachable straps. Here the strap 3 is formed as a double layer 10, 10', and one end 1 1 of the strap is passed beneath the end 8, around the rope 1 and beneath the hinge 7 and beneath the other end 8'. The layers 10, 10' are then parted downstream of the end 8' to form a loop to accommodate a second locking pin 12. The procedure is repeated at the other end of the strap with the lower adjacent rope (not shown).

Thus the straps are located firmly in place, but may be removed, e.g. for replacement, merely by withdrawing the pins 12 and 9. In this way the straps may be removed without detaching the ropes 1.

CLAIMS 1. A clamp for connecting a first elongate flexible member to a second elongate member, the clamp comprising first and second parts hingedly connected at one end and shaped to extend round the second elongate member, and means for holding the other ends of the shaped members together so that the shaped members are held in a clamping position around the second elongate member, wherein the shaped members have means for locating the flexible member around the second elongate member and preventing or limiting lateral movement of the flexible member in a direction along the second elongate member.

2. A clamp as claimed in claim 1, wherein each shaped member is in the form of a substantially rectangular, curved frame, the frames engaging along one side to form the hinge connection and being engageable along the opposite side, in the said clamping position, by the holding means.

3. A clamp as claimed in claim 2, wherein in the said clamping position the said opposite sides of the frames define an aperture for accommodating a pin holding the shaped members in the clamping position.

4. A clamp as claimed in claim 1, 2 or 3,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A clamp The present invention relates to a clamp for connecting a first elongate flexible member to a second elongate member, particularly but not exclusively for connecting vertical straps to horizontal ropes of containment or barrier nets. It is known to protect the marine risers of an offshore production platform from damage by drifting vessels by means of a net. The net is constructed from parallel horizontal ropes joined by vertical web straps. As the breaking loads of the ropes and the straps is in the order of 220 tonnes and 40 tonnes respectively, a substantial connection between the ropes and the straps is required. The invention provides a clamp as claimed in claim 1. Embodiments of the invention will now be described with reference to the accompanying drawings, wherein: Figure 1 is a front view of a containment or barrier net; Figure 2 is an end view of a clamp in accordance with the invention connecting a strap to a rope; Figure 3 is a plan view of the clamp of Fig. 2; Figure 4 is a side view of the clamp of Fig. 2; Figure 5 is an underside view of the clamp of Fig. 2; Figure 6 is an end view of a clamp similar to Fig. 2 wherein the strap is detachably held. In Fig. 1, a typical containment net comprises a plurality of horizontal ropes 1 extending between end posts 2. The ropes 1 are connected to each other by vertical straps or webs 3. In Figs. 2 to 5 a clamp 4 comprises first and second shaped members 5, 5' shaped to extend around the ropes 1. As can be seen more particularly from Figs. 2 and 4, the shaped members are formed as substantially rectangular frames curved at right angles to the plane of the rectangle. At one end 6, 6', the shaped members 5, 5' are interlocked to form a hinge 7. At the other end 8, 8' the shaped members 5, 5' are shaped so that they may be overlapped as shown in Figs. 2 and 5 so as to define an aperture to accommodate a locking pin 9. In this position the shaped members 5, 5' bite into the surface of the rope 1 so that the clamp 4 cannot be moved along the rope 1. The strap 3 passes around the rope 1, beneath the ends 6, 6' forming the hinge 7 and beneath the ends 8, 8' of the shaped members 5, 5'. Thus the strap 3 transmits its load directly onto the rope. The clamp 4 merely locates the strap 3 in the correct position on the rope. The clamp 4 also locates the strap 3 on the rope 1 with the optimum shape. The clamp does not transmit any of the tensile loads as the load path is directly through the strap loop and into the rope 1. To aid the "digging-in" action of the clamp 4 on the rope 1, the rope is constructed preferably of parallel fibres and is provided with a plastics coating (e.g. a hard polyurethane material) over e.g. 3mm diameter of the rope. Such a rope has a considerable resistance to the crushing action of the loop stresses generated by the clamp 4. An example of such a rope is ICI Parafil (R.T.M.). The clamp itself, i.e. the shaped members 5, 5', may be made of any suitable material, e.g. metal rod, wire or strip, or plastics material. As can be seen from Fig. 6, the clamp 4 can be used to locate detachable straps. Here the strap 3 is formed as a double layer 10, 10', and one end 1 1 of the strap is passed beneath the end 8, around the rope 1 and beneath the hinge 7 and beneath the other end 8'. The layers 10, 10' are then parted downstream of the end 8' to form a loop to accommodate a second locking pin 12. The procedure is repeated at the other end of the strap with the lower adjacent rope (not shown). Thus the straps are located firmly in place, but may be removed, e.g. for replacement, merely by withdrawing the pins 12 and 9. In this way the straps may be removed without detaching the ropes 1. CLAIMS

1. A clamp for connecting a first elongate flexible member to a second elongate member, the clamp comprising first and second parts hingedly connected at one end and shaped to extend round the second elongate member, and means for holding the other ends of the shaped members together so that the shaped members are held in a clamping position around the second elongate member, wherein the shaped members have means for locating the flexible member around the second elongate member and preventing or limiting lateral movement of the flexible member in a direction along the second elongate member.

4. A clamp as claimed in claim 1, 2 or 3, wherein the shaped members are formed from wire, rod or strip.

5. A clamp substantially as herein described with reference to Figs. 1 or 2 of the accompanying drawings.

6. A net having a plurality of substantially horizontal ropes and a plurality of substantially vertical webs interconnecting the ropes by means of clamps as claimed in any one of the preceding claims.

7. A net as claimed in claim 6, wherein each web interconnects two adjacent ropes only.

8. A net as claimed in claim 7, wherein each web is detachably connected to each clamp by passing one end of an endless loop of web in a double layer around each rope and holding in place by means of a stop member passed between the two web layers adjacent the said other ends of the shaped members.

9. A net as claimed in claim 8, wherein the stop member is a retractable pin.