This invention relates to a device for clamping to a pipe, cable or other elongate element, as well as to apparatus and a method for fitting such a clamping device to a pipe, cable or other elongate member. The invention finds particular, but not exclusive, application of the clamping device, clamping device fitting apparatus and clamping device fitting method to fitting a clamp to a pipe used in offshore operations, such as when connecting a smaller diameter pipe to a larger diameter pipe in a piggy-back type installation operations.

Clamping arrangements for clamping two pipes in parallel relationship in piggy-back configuration are known and used in offshore pipe laying operations using a pipe lay vessel. A conventional clamp installation of the lay tower or lay ramp of the pipe lay vessel requires manual intervention close to the pipes to position, align and manually clamp the pipes. Since the pipes need to be advanced during pipe laying operations, it is necessary to temporarily reduce the pipe linear travel speed, or to temporarily stop the pipe lay altogether, when the clamp installation process is carried out. Both of these conventional operations potentially result in the pipes being subjected to additional stresses, due to dynamic impacts caused by motion of the vessel. Furthermore, the time spent in manually installing conventional pipe clamps while the pipe laying operation is halted increases the time needed for completing the pipe laying operation. It would also be desirable to provide an improved clamping device for fitting to a pipe, or for fitting to other elongate elements, such as a cable.

According to the invention from a first aspect there is provided a device for clamping to a pipe, cable or other elongate element, comprising a unitary elastically deformable clamp in the form of two clamping limb portions connected by a clamping saddle portion, the clamping limb portions being located adjacent one another, when the clamp is un-deformed, so as to define, together with the saddle portion, a ^" principal central opening for the pipe, cable or other elongate member and so that the clamp substantially encompasses the pipe, and the clamping limb portions being movable apart by elastic deformation of the clamp to create an opening between them, enabling the open clamp to be fitted over the pipe, cable or other elongate member and released, to allow the clamp to snap into engagement around the pipe, cable or other elongate member.

Being of unitary construction, the clamp is relatively cheap to manufacture. Furthermore, relying merely on the elastic properties of the unitary clamp is a simple and effective way of providing the necessary clamping force. Since the clamping limb portions are located adjacent one another, so that the clamp substantially encompasses the pipe, when the clamp is engaged with the pipe, the limb portions need to be pulled apart by an amount (at the narrowest distance separating them) substantially equal to at least the external diameter of the pipe or the internal diameter of the principal central opening in the clamp, to enable the clamp to be fitted to the larger pipe. This clamping arrangement ensures high clamping integrity for the clamp and pipe and minimises the likelihood of the clamp being inadvertently separated from the pipe.

Suitably, the clamp can be made of a durable composite plastics material. This makes the clamp light in weight and avoids the use of metal components.

The clamping device may further comprise a locking member for locking the clamping limb portions in position adjacent one another, when the clamp is snapped into engagement around the pipe. The locking member increases the reliability of the grip of the clamping device on the pipe, cable or other elongate member.

In a preferred arrangement that is simple and cheap to implement and very effective in use, the locking member comprises a generally U-shaped clip defining a pair of limbs which are slidably mounted within respective first grooves formed in one of the clamping limb portions for movement of the locking member towards and away from the other clamping limb portion and which are arranged for engagement with the other limb portion, when the clamp is snapped into engagement around the pipe, cable or other elongate member, to lock the clamping limb portions in position adjacent one another.

In a preferred embodiment, the limbs of the U-shaped clip are provided with respective ratchets for engagement with corresponding first ratchets in the respective first grooves, when the clamp is snapped into engagement around the pipe, cable or other elongate member, to lock the clamping limb portions in position adjacent one another. This is a simple and reliable way of holding the clamp closed. Additionally, second grooves may be formed in the other clamping limb portion of the clamp in alignment with the first grooves formed in the one clamping limb portion of the clamp, and the ratchets of the limbs of the U-shaped clip are arranged for engagement with corresponding second ratchets in the respective second grooves, when the clip is moved to a position remote from the other clamping limb portion, in which position the clamp is unlocked.

The two limbs of the generally U-shaped clip may be angled towards one another. In this way, a preload clamping force is produced and maintained, to ensure the proper engagement of the ratchet teeth and take up any backlash from the ratchet teeth when they are fully engaged.

Desirably, the bridge of the generally U-shaped clip, connecting its two limbs, is arched towards the free ends of the limbs. This imparts greater flexibility to the limbs of the clip, to assist engagement of the ratchet teeth.

When the clamping device is adapted for use in offshore pipe laying operations where a second, smaller diameter, pipe is to be held in piggy-back relationship to the initial, larger diameter, pipe, the clamping limb portions of the clamp together define a passageway through the clamp for a further pipe, cable or other elongate member, when the clamping limb portions are located adjacent one another, for holding the second pipe, cable or other elongate member to the first- mentioned pipe, cable or other elongate member in spaced relationship thereto. The inner surfaces of the clamping saddle portion and clamping limb portions of the clamp are preferably formed with ridges for gripping the exterior of the initial pipe, cable or other elongate member. In this way, the clamping device may be more reliably clamped to the initial pipe, cable or other elongate element.

According to a preferred embodiment, a cut-away portion of one of the clamping limb portions increases the gap between the clamping limb portions for given, relative, pulled-apart portions of the clamping limb portions. This enables the clamp to be opened and snapped into engagement with the pipe, cable or other elongate member, without overstressing the clamp, thereby avoiding the risk, that it may break when it is being fitted.

According to the invention from a second aspect, there is provided apparatus for fitting a clamping device according to the first aspect of the invention to a pipe, cable or other elongate member, comprising:

(i) means for supporting the pipe, cable or other elongate member;

(ii) a guide for the clamping device, having an input end laterally offset from the supporting means and a discharge end; and

(iii) means for advancing the clamping device, received at the input end of the guide, along the guide to its discharge end, wherein the guide is provided with means for moving the clamping limb portions apart during advancement of the clamping device along the guide, to create said opening between the clamping limb portions, and the discharge end of the guide is arranged to discharge the open clamping device around the pipe, cable or other elongate member when supported by the supporting means, thereby allowing the clamp to snap into engagement around the pipe, cable or other elongate member.

Such apparatus enables the clamping device to be fitted to and! ^{^} engaged with the pipe, cable or other elongate element while the latter is still moving at its normal speed. Furthermore, the lateral offset allows the clamping device to be loaded onto the guide at a location remote from where the pipe, cable or other, elongate member is supported.

According to a preferred embodiment, the clamping device fitting apparatus further comprises means for advancing the pipe, cable or other elongate member along an advancement path, wherein the means for advancing the clamping device is arranged to discharge the clamping device from the guide substantially collinearly with the advancement path at the location of the discharge end of the guide. With this arrangement, it is possible to fit the clamping device, or several clamping devices at successive relative, spacings, to the initial pipe (or cable or other elongate element) , while that pipe is being advanced at its normal pipe laying speed.

When the clamping device includes a generally U-shaped locking clip, the clamping device fitting apparatus is preferably capable of automatically sliding the clip from its open to its closed position to lock the clamping device in position, after the clamping device has been clamped onto the initial pipe. According, therefore, to a preferred embodiment, the apparatus further comprises a closing device for moving the locking member towards the other clamping limb portion of the clamp for engagement with the other limb portion, when the clamp is snapped into engagement around the pipe, cable or other elongate member, to lock the clamping limb portions in position adjacent one another.

Various forms of device are known that will function as the closing device. According to a preferred arrangement, the closing device comprises a roller- supported belt located on each side of the advancement path for progressively moving the locking member towards the other clamping limb portion of the clamp for engagement with the other limb portion, when the clamp is snapped into engagement around the pipe, cable or other elongate member, to lock the clamping limb portions in position adjacent one another.

A skilled person will be aware of various mechanical devices that can function as the means for moving the clamping limb portions apart. However, an especially simple and effective way of achieving this result is a progressive widening, or flaring, of the guide between its input end and its discharge end.

Conveniently, the means for advancing the clamping device, received at the input end of the guide, along the guide to its discharge end comprises a pusher for pushing against the first clamping device of a plurality of clamping devices arranged on the guide at successive positions along the guide between its input end and its discharge end, so as to discharge the last clamping device at the discharge end of the guide onto the pipe.

According to the invention from a third aspect, there is provided a method for fittiag a clamping device according the first aspect of the invention around a pipe, cable or other elongate member, comprising the steps of:

(i) supporting the pipe, cable or other elongate member;

(ii) advancing the clamping device along a guide path from a position laterally offset from the pipe, cable or other elongate member;

(iii) moving the clamping limb portions apart during advancement of the clamping device along the guide path, to create said opening between the clamping limb portions; and

(iii) discharging the open clamping device around the pipe, cable or other elongate member from the guide path, thereby allowing the clamp to snap into engagement around the pipe, cable or other elongate member.

To ensure the integrity of the clamping of the clamping device onto the initial pipe, the clamping device is locked in position, after the clamp has snapped into engagement around the pipe, cable or other elongate member .

It is normally preferred that a succession of contiguous clamping devices is provided between the inlet end and the discharge end of the guide path, so that on pushing a further clamping device onto the inlet end, a clamping device is discharged from the discharge end of the guide path onto the initial pipe. This enables discharge of the clamping device onto the pipe to be effected remotely, without risk of interference with the motion of the advancing pipe. It will be appreciated that the pushing of a further clamping device onto the inlet end of the guide path needs to be synchronised with the intended position at which the clamping device discharged from the discharge end of the guide path is to be clamped onto the initial pipe.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings , in which :

Figure 1 is a general perspective view from above and from one side of one form of pipe clamping device in accordance with the invention, comprising a unitary pipe clamp;

Figure 2 is a front view of the pipe clamp;

Figure 3 is a general perspective view from above and from the other side of the pipe clamping device, which also includes a locking member, shown in its unlocked position;

Figure 4 is the same general perspective view of the pipe clamp, similar to that that of Figure 3 but showing the locking member in its locked position; Figure 5 is a general perspective view of one form of apparatus in accordance with the invention for fitting the clamp to a pair of pipes of different diameter, to hold the smaller pipe in piggy-back, spaced, relationship to the larger diameter pipe;

Figure 6 is a diagrammatic side view of significant components comments of the clamp fitting apparatus, showing how the pipe clamp is fitted to the pair of pipes ; and

Figures 7A to 7E are cross-sectional views on an enlarged scale, taken along the section lines 7A - 7A to 7E - 7E in Figure 6, showing successive stages in fitting the pipe clamp to the pair of pipes.

The description which follows is given in the context of fitting a clamping device to a larger diameter pipe, to hold a smaller ^" diameter pipe in piggy-back relationship to the larger diameter pipe, as is required in certain offshore pipe laying operations. However, the concepts and relevant constructional features disclosed can be applied where a clamping device is to be fitted to a single pipe only, and also whether or not the pipe, or the pair of pipes in piggy-back relationship, are being used in pipe laying operations.

Furthermore, although the preferred use of the invention is for fitting the clamping device to a pipe, the disclosed embodiments may instead be fitted in an analogous way to cables, or indeed any other elongate member, as required. Thus, the clamping devices can be used in situations such as flexible or electric cable laying and attaching cables or hoses to a support or the like. Furthermore, the clamping devices may have a specific purpose in addition to functioning purely for clamping, such as being a quick snap, cable or pipe, tidy.

Referring now to the Figures generally, there is shown a pipe clamping device to be used in offshore pipelay operations, comprising a piggy-back pipe clamp 1 that is to be fitted to a larger diameter pipe 2, to hold a smaller pipe 3 in piggy-back, spaced, relationship to the larger diameter pipe, while allowing the smaller diameter pipe to slide in the pipe clamp, in the direction of its longitudinal axis .

The clamp consists of a unitary, elastically deformable, body 4, in the form of two clamping limb portions 4a, 4b connected by a clamping saddle or bridge portion 4c. In Figures 1 to 4, the pipe clamp is shown in its un- deformed state, in which the clamping limb portions 4a, 4b are angled inwardly and towards each other, so that they are located adjacent one another. The saddle and limb portions 4a, 4b, 4c together define a principal central opening 5 for receiving the larger diameter pipe and a secondary opening 6 for the smaller diameter pipe. As shown, there is a small gap 7 between facing surfaces of the limb portions, but in accordance with a modified arrangement (not shown) , the facing limb portion surfaces may actually touch each other.

The clamp is designed to be deformed, without breaking, so that the limb portions can be pulled apart to create an opening between them, enabling the open clamp to be fitted over the pipes 2,3. Then, on releasing the limb portions, the clamp snaps into engagement with the larger diameter pipe 2 , owing to the elasticity of the clamp body 4 .

Preferably, the clamping saddle and limb portions are formed with internal ridges 8 to improve the grip of the clamp on the pipes 2 .

Depending on the magnitude of the clamping force required, the elasticity of the clamp body and the stiffness of the clamping limb and saddle portions, the internal diameter of the principal opening 5 , defined by the internal ridges 8 , needs to be slightly smaller than the external diameter of the larger diameter pipe (when the clamping device is undeformed) , so that, when fitted to the larger diameter pipe, the clamp will be firmly engaged with it.

In order to give the clamp the necessary elastic properties, it may be made from a durable plastics material or composite. Many known plastics materials or composite are suitable for the clamp body, but a particularly suitable material is a PVDF (polyvinylidene fluoride) based material from the thermoplastic composite range . The geometry of the clamp body will need to take account of the stiffness that the clamp body is required to display, which will affect how hard it is to open and close the clamp.

On the other hand, the diameter of the secondary opening 6 in the clamp is slightly larger than the external diameter of the smaller diameter pipe 3. This arrangement holds the smaller diameter pipe 3 at a fixed separation from the larger diameter pipe, while allowing it to be displaced in the direction of the longitudinal axis of the larger diameter pipe.

As best shown in Figures 1 and 2, aligned, transversely orientated, grooves 4a', 4b' are formed in the clamping limb portions 4a, 4b in the opposite front faces of the clamp. With particular reference to Figures 3 and 4, a pair of limbs of a generally U-shaped clip 9, forming a locking member, are slidably mounted in the grooves 4a, 4b so that the locking clip can be slid between an open position shown in Figure 3, in which the clip limbs are located solely in grooves 4a', and a closed position shown in Figure 4, in which the clip limbs are located in both grooves 4a', 4b' of both clamping limb portions 4a' , 4b' and the bridge or base of the U-shaped clip is located in an end groove 10 formed in the side face of clamp limb portion 4a and connecting the grooves 4a' formed in the opposite front faces of the clamping limb portion 4a.

The U-shaped locking clip 9 is made from a resilient material, in order that its limbs can flex slightly, to enable the co-operating ratchet teeth to engage and disengage. Preferably, the material from which the clip is made is the same as that used for the unitary clamp body, i.e. a durable plastics material or composite, such as a PVDP based material from the thermoplastic composite range .

Formed in the base of each groove 4a' is a set of ratchet teeth 11, with which a set of co-operating ratchet teeth (not shown) formed on the inside surface of each clip limb engages when the locking clip 9 is in its open position, to hold the clip captive on the clamping limb portion 4a.

Formed in the base of each groove 4b' is a set of ratchet teeth 12, with which the aforementioned ratchet teeth formed on the inside surface of each clip limb engage when the locking clip is in its closed position, to lock the clamping limb portions 4a, 4b in position adjacent one another clamped, with the clamping saddle portion 4c, against the larger diameter pipe 2 (with a small clearance from the outside of smaller diameter pipe 3) .

In order to move the clip as between its open and closed positions, the engagement force between the ratchet teeth on the locking clip and the ratchet teeth in each groove 4a', 4b' is overcome by applying adequate displacement force on the locking clip 9. A back angle on the cooperating ratchet teeth assists their engagement, when the clip is slidably displaced into its closed or locking position, and resists unintended disengagement. Similarly, a back angle on the ratchet teeth resists unintended separation of the captive locking clip from the clamping limb portion 4, when it is in its unlocked or open position.

The two limbs of the U-shaped locking clip may be angled towards another. In this way, a pre-load clamping force can be produced and maintained, to take up any backlash from the ratchet teeth, when fully engaged. In addition, as shown in Figure 3, adequate flexing of the limbs of the locking clip 9 may be assisted, by arching the bridge or base of the clip towards the free ends of its limbs, so as to give the U-shaped clip a W-shaped profile. The smaller diameter pipe 3 can be fitted to the larger diameter pipe 2 in piggy-back fashion using the described clamp, by performing manual operations close to the pipes to position, align and clamp them in place. However, this increases installation time, since the pipelay operation has to be stopped, or at least slowed down by reducing the advancement velocity of the pipes, to allow the manual operations to be carried out, before normal pipelaying operations are resumed. Furthermore, the pipe will be subjected to additional stressing during this time, due to dynamic impacts resulting from vessel motion on the sea surface.

Figures 5 and 6 show an apparatus that will fit the clamping device to the two pipes at the same time as they are being advanced at the same speed along parallel axes, during the normal pipelaying process. The apparatus, denoted generally by reference numeral 100, comprises a pipe supporting and advancing means, diagrammatically shown at 101, which supports the larger and smaller diameter pipes 2,3 in parallel, spaced apart, relationship and advances them at the same speed V in the direction of their longitudinal axes. Such supporting and advancing means are well known in the art and do not need to be further described herein.

The clamp fitting apparatus also comprises a clamp guide 102, which is carried on a support plate 103. The clamp guide has an input end 104, to which clamping devices 1 as shown in Figure 3 are fed one after the other, and a discharge end 105 from which the clamps 1 are discharged one after the other, for clamping to the pipe 2 to hold the pipe 3 in piggy-back relationship thereto, as will be described in detail hereinbelow. The guide 102 is in the form of a half-cylinder, as can be appreciated from Figures 7A to 7C, whose cylinder axis is curved, so as to define a semicircular or similarly shaped guide path axis as viewed from the side (Figure 6) . Accordingly, the input end 104 is laterally offset, and therefore remote from, from the supporting and advancing means 101, so that clamping devices 1 can be loaded onto the clamp guide 102 safely and easily. The axis of the clamp guide 102 at its discharge end is aligned with the axes of the larger and smaller diameter pipes 2,3 and is collinear with the axis of the larger diameter pipe 2, so as to position each discharged clamping device around the advancing pipes 2,3 (Figure 7C) .

A reciprocating pusher 106 is provided adjacent the input end of the clamp guide. On its forward stroke, it pushes a clamping device 1 onto the guide 102, and on its return stroke, it returns ready to push the next clamping device onto the guide. Each clamping device on the clamp guide is in contact with the next clamping device. Therefore, whenever the pusher 106 pushes a clamping device onto the clamp guide, the clamping device at the discharge end will be discharged from the clamp guide. It should be noted that in Figures 5 and 6, only some of the succession of contiguous clamping devices are shown.

With particular reference to Figure 6 and a comparison between Figures 7A and 7B (Figure 7A being a sectional view at the inlet end of the clamp guide and Figure 7B being a sectional view at the position on the clamp guide at which the clamping device is required to be opened sufficiently to clear the full diameter of the larger diameter pipe 2) , the clamp guide progressively widens between its input end 104 and its discharge end 105. Accordingly, as each clamping device is advanced along the guide 102, the limb portions 4a, 4b of the clamp body are progressively driven apart , to open the clamping device sufficiently for its clamping limb portions 4a, 4b to clear the larger diameter pipe 2.

As the clamping device is advanced further towards the discharge end 105 of the clamp guide, it does not need to be further opened and in fact it can start to be closed around the pipe 2 (and the pipe 3) . Accordingly, as shown in Figure 6, the clamp guide 102 can be allowed to progressively narrow between the position along the guide at which the clamp guide is required to produce the maximum opening of the clamping device (Figure 7B) and the discharge end 105 of the clamp guide (Figure 7C) . It will be appreciated, however, that it is not essential that the guide narrow in the way explained, and it is possible for the transverse dimensions of the guide to remain constant along the length of the guide between the position of maximum clamping device opening and the guide discharge end, or even to increase further over this length.

The clamping device fitting apparatus 100 also comprises a closing device 107 for locking each clamp after it has been positioned on the two pipes 2,3. The closing device is located beyond the discharge end 105 of the clamp guide 102 in the direction in which the pipes 2,3 are being advanced continuously. The closing device 107 comprises a pair of continuously driven endless belts on respective sets of driven and idler rollers, one on each side of the advancing pipes 2,3. As each (open) clamping device 1 passes through the closing device, the endless belts centralise the clamping device 1 and displace the locking clip to its closed position to lock the clamp in position .

Operation of the clamping device fitting apparatus will now be described, with reference to Figures 5, 6 and 7A to 7E.

Figure 7A shows a clamping device 1 which has just been pushed onto the inlet end 104 of the guide. The clamping device remains un-deformed, since the radial dimension of the outer surface of the clamp guide matches that of the principal opening 6 in the clamp body, with a small clearance.

As further clamping devices are successively pushed onto the inlet end of the clamp guide, the clamping device 1 is progressively advanced along the guide towards its discharge end 105. Since the radial dimension of the guide initially progressively increases along the guide, the clamping limb portions of the clamping device 1 are progressively driven apart as each clamping device advances along the clamp guide 102, until the clamping device reaches the position shown in Figure IB, at which the opening between the clamping limb portions at its maximum and is adequate to clear the larger diameter pipe 2.

On further advancement along the clamp guide 102, whose radial dimension now progressively decreases, the clamping device starts to close up around the pipe as the clamping device progresses into alignment with the pipes 2,3, until it reaches the discharge end of the pipe (Figure 7C) , when it is positioned co-axially around the continuously advancing pipes 2,3. When the next clamping device is pushed onto the inlet end of the clamp guide, the clamping device 1 at the discharge end 105 is pushed off the clamp guide 102, thereby releasing the clamping limb portions 4a, 4b and allowing the clamp body to snap into engagement around the advancing pipes 2,3 (Figure 7D) .

As the pipes 2,3 advance further, they convey the clamping device 1 to the closing device 107, which displaces the locking clip 9 to its closed position, to lock the clamping device 1 in position on the larger pipe 2.

Further clamping devices can be clamped and locked onto the larger diameter pipe 2 at different axial positions in the manner described, so as to hold the smaller diameter pipe 3 at a substantially uniform spacing form the larger diameter pipe 2, while allowing relative axial adjustment of the longitudinal position of the smaller diameter pipe 3 relative to that of the larger diameter pipe 2.

With correct sizing of the principal opening in the clamp body relative to the external diameter of the larger diameter pipe, specifically by sizing it to be slightly smaller than the outside diameter of the larger pipe, the clamping device can be made to grip the larger diameter pipe securely without using any locking clip. However, the use of the locking clip is preferred, because it serves to ensure the integrity of the grip of the clamping device.

As best shown in Figure 2, the width of the gap 7 between the two clamping limb portions 4a, 4b is very small and these limb portions are located adjacent each other, when the clamp is un-deformed, so that the clamp substantially encompasses the larger diameter pipe when it is fitted to that pipe. Accordingly, the clamping limb portions of the clamp need to be separated by an amount, at the narrowest distance separating them, that it is more or less equal to at least trie external diameter of the larger pipe, or the internal diameter of the principal central opening in the clamp, when the clamping device is to be fitted over the larger diameter pipe, as can be appreciated from Figure 7B , which shows the clamping device at its widest opening. In this way, high clamping integrity is ensured.

It will also be noted from Figure 7B and Figure 7C that a cut-away portion 13 of the clamping limb portion 4a increases the gap between the clamping limb portions 4a, 4b for given, relative,, pulled-apart positions of the clamping limb portions, as compared with the gap that would otherwise exist. This arrangement safeguards the clamp against overstressing when it is opened for fitting to the larger diameter pipes .

It will be appreciated that the disclosed clamping device itself offer a number of advantages, including:

(i) It is of unitary construction, and therefore simple and cheap to manufacture .

(ii) It can be made of plastics material (clamp body and locking clip) , which keeps manufacturing cost to a minimum. (iii) It does not need to be made of (more expensive) metal .

(iv) It is of lightweight construction.

(v) The snap-on clamping design provides reliable grip with the larger diameter pipe .

(v ) The ratchet locking mechanism is simple and effective.

(vii) The ratchet locking mechanism applies a pre- clamping force that accommodates pipe outside diameter manufactuiring tolerances.

(viii) The ratchet locking mechanism avoids any backlash from the ratchet teeth.

It will be appreciated that the disclosed clamping device fitting apparatus and method offer a number of advantages , including :

(i) Clamping device loading is effected remote from the region where the pipe laying operations themselves are taking place.

(ii) Clamping devices may be fitted to one or more pipes while the pipes continue to be advanced at their normal speed, thus minimising operational time, especially during pipe laying operations .

(iii) Keeping the inlet end of the clamping device guide laterally offset from the path of the pipe (s) being laid helps to ensure the safety of operating personnel .