Abstract:
The present invention relates to a clamp that can be used for repairing a rupture in a pipe. The clamp includes a wrapping assembly comprising strapping that at least partially extends about the pipe, an adjustment device that is suitably in form of a claps for adjusting the effective length of the strapping about the pipe and a tensioning device that is suitably in the form an over center lever mechanism that is operable to place the wrapping assembly under different tensions.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the national stage of International Application No. PCT/AU2009/001507, filed Nov. 19, 2009, which application claims priority to Australian Pat. App. No. 2008905980, filed Nov. 19, 2008, the contents of which are incorporated herein by reference. 
     FIELD OF THE PRESENT INVENTION 
     The present invention relates to a clamp and in particular to a clamp that can be used for repairing a rupture in a pipe in any application such as a water main or a fire main of a maritime vessel. The clamp may be used in any industrial application including pipelines of chemical processing plants. 
     BACKGROUND OF THE PRESENT INVENTION 
     There are at present a vast number of different clamps commercially available. An example of a clamp that has been widely used and is available under the trade mark BAND-IT comprises: i) steel strapping that is cut from a reel at any chosen length, and ii) a buckle through which the strapping is threaded to form a loop around an object being clamped. A tensioning tool is fitted and operated to tension the steel strapping wrapped about the object and the buckle is crimped closed to prevent the strapping from sliding through the buckle to maintain the required tension. The tensioning tool is removed and the strapping extending from the buckle cut from the reel and trimmed as desired. One of the disadvantages of this type of clamp is that the cut end of the steel strapping has been known to cause lacerations. In addition, the clamp requires an inventory of tools and usually multiple personnel to fit the strapping about the object being clamped. 
     Many alternative clamps are also commercially available such as conventional hose clamps, and two piece clamps of fixed diameter that are bolted together. 
     It is an object of the present invention to provide an alternative clamp. 
     SUMMARY OF THE PRESENT INVENTION 
     According to the present invention there is provided a clamp suitable for patching a rupture in a pipe, the clamp comprising: 
     a wrapping assembly that can at least partially encircle a pipe and be positioned on a rupture of the pipe, wherein the wrapping assembly includes strapping and an adjustment device for adjusting the effective length of the strapping that is wrapped about the pipe; and 
     a tensioning device that is operable to place the wrapping assembly about the pipe under different tensions so as to allow pressure applied by the wrapping assembly to the rupture to be adjusted. 
     It will be appreciated that the tensioning device can be operable so that the clamp may either entirely or only partially prevent leakage from the pipe. 
     In an embodiment, the adjustment device can frictionally engage the strapping at any desired point to selectively set the effective length of the strapping. 
     In an embodiment, the adjustment device includes an abutment surface and the strapping can slid through the adjustment device so as to frictionally engage the abutment surface at the desired point along the strapping to selectively set the effective length of the strapping. In other words, the strapping can slid through the adjustment device in a continuously progressive manner to achieve the desired effective length of the strapping. 
     In an embodiment, the wrapping assembly is releasably connected to the tensioning device to allow the clamp to be installed about the pipe. 
     When in use, the wrapping assembly may encircle one part of the pipe and the tensioning device may encircle the remaining part of the pipe to totally encircle the pipe. In other words, the wrapping assembly encircles part of the pipe and the tensioning device straddles between or interconnects the wrapping assembly so that the clamp extends continuously around the pipe. 
     In an embodiment, the effective length of the strapping encircles at least part of the pipe and passes through the adjustment device, and an end of the strapping extends from the adjustment device and the effective length can be reduced by pulling on the end extending from the adjustment device so as to slide the strapping through the adjustment device. 
     By pulling on the strapping, the adjustment device provides a coarse level of adjustment so that the device can be fitted to pipes of various sizes. 
     The strapping may be any form of strapping including steel strapping, plastic webbing or fabric strapping. In the situation in which the strapping is, for example a fabric type of strapping, the adjustment device may be any suitable device including inter-fitting male and female snap lock clips; sliding adjustors; sliding buckles having strapping threaded there through that can slide through the buckle; buckles having pins that receive one of a series of holes in the strapping to fix the effective length of the strapping in position. In an embodiment, the adjustment device includes a clasp having an open and closable flap and the strapping is wedged between the flap in a closed position and the abutment surface, thereby securing the effective length of the strapping. 
     The clasp is configured such that the flap contacts the strapping passing through the clasp and tension in the strapping pulls the strapping in a direction through the clasp that moves the flap toward the abutment surface, thereby wedging the strapping between the flap and the abutment surface. 
     The flap may also be biased, suitably by a spring, in a direction that moves the flap toward the Abutment surface. 
     In order to release the tension in the strapping, the flap can be manually moved away or lifted into a neutral non-engaging position in which the strapping is not wedged between the flap and the abutment surface. The effective length of the strapping can be increased by moving the flap into the neutral position which allows the strapping to slide through the adjustment device. 
     The strapping may be used in any configuration including a single layer in which the strapping extends from one point of the wrapping assembly to the adjustment device. In an embodiment the strapping is arranged in a loop in which the strapping extends from the adjustment device and loops back and through the adjustment so that the effective length of the strapping is formed by two sub-sections of the strapping. 
     The tensioning device may comprise any mechanism for tensioning the device about the pipe including: a ratchet mechanism; a latch mechanism; a rack and pinion mechanism; a geared mechanism; a screw threaded mechanism; a winding mechanism and so forth. 
     In an embodiment, the tensioning device includes a lever mechanism that can be moved between an unloaded neutral position in which the wrapping assembly is located in an initial circumferentially expanded state and a loaded working position in which the wrapping assembly is located in a circumferentially contracted state. 
     Suitably, the lever mechanism is an over centre lever mechanism in which moving the lever from an unloaded neutral position to a loaded position involves pivoting the handle through a region in which the load in the mechanism peaks, and in turn the tension of the wrapping assembly peaks. In other words, when the lever is located in the loaded working position, the lever requires external influences to be moved into the unloaded neutral position. 
     Similarly, when the handle is moved from an unloaded neutral position to a loaded working position, the handle passes through the region in which the load on the mechanism is at a peak, and in turn the tension of the wrapping assembly peaks. 
     In an embodiment, the clamp includes a lock that locks the tensioning device so as to prevent the device from unintentionally releasing or moving from the loaded working position to the neutral unloaded position. The lock may be operable so as to be selectively activated or locked, and deactivated or unlocked when the tensioning device is located in the loaded locking position. 
     In the situation in which the tensioning device is in the form a lever mechanism, suitably the lock is operable to selectively allow or prevent pivotal movement of the lever when in the loaded working position. Even more suitably, the locking mechanism includes a strap, which may or may not extend from the strapping that is wrapped about the pipe, and which connects to the handle of the lever mechanism to retain the handle in the loaded working position. 
     In an embodiment, the lever mechanism includes a handle that is pivotally connected to the wrapping assembly at a first pivot point and the lever mechanism further includes a linkage arm that is pivotally connected to the handle at a second pivot point. The linkage arm may be pivotally connected to the wrapping assembly at a further pivot point. In this situation, the wrapping assembly and lever mechanism totally encircle the pipe when fitted thereto. 
     In an embodiment, the lever mechanism includes an adjustor for adjusting the load or purchase of the lever mechanism when in the loaded working position. 
     In an embodiment, the adjustor is operable to move the location of the second pivot point at which the linkage arm is pivotally connected to the handle along either one of the handle and/or the linkage arm in a continuous progression. Suitably, to increase the load on the lever mechanism, the adjustor is operatable to move the second pivot point away from the first pivot point of the handle to the wrapping assembly and to reduce the load on the lever mechanism, the adjustor is operatable to move the second pivot point toward the first pivot of the handle and the wrapping assembly. 
     In an embodiment, the adjustor includes: 
     i) a shaft that is moveable within a housing, suitably the housing is connected to or integrally formed with the handle, and the linkage arm is pivotally connected to the shaft; and 
     ii) a stopping piece that can be moved along the shaft, and the stopping piece abuts against the housing and is thus operable to move the point of connection between the linkage arm and the handle. 
     In an embodiment, the shaft is a screw threaded shaft and the stopping piece is a wing nut that is finger adjustable when the lever is in an unloaded neutral position. 
     It will be appreciated that the clasp of the strapping described above provides a first means for adjusting the size of the clamp and in particular enables a coarse level of adjustment to an initial expanded circumference. Operation of the lever mechanism from the unloaded position to a loaded working position then further reduces the circumference of the clamp to a contracted circumference. The size of contracted circumference of the clamp can be tuned to a fine level by operation of the adjustor as desired by releasing the lever to the unloaded position, operating the adjustor, and moving the lever back into the loaded working position. 
     In an embodiment, the linkage arm comprises one or more than one non-linear members that are shaped to extend over the pivot connection of the handle to the wrapping assembly. 
     In an embodiment, the lever mechanism includes a cam body that interconnects the linkage arm to the wrapping assembly, and the cam body is pivotally connected to the wrapping assembly at a first spacing from the pipe to which it is fitted, and the cam body is pivotally connected to the linkage arm at a second spacing from the pipe that is greater than the first spacing. 
     The clamp may include a patch for covering a rupture in the pipe or alternatively, the patch may be an entirely separable component from the wrapping assembly or tension device. In the situation in which the patch is connected to the clamp, and suitably forming part of the wrapping assembly, the patch includes a metal plate or band which is preferably in the form of a spring stainless steel band. 
     The plate or band may be rigid and have any pre-formed curvature to fit a range of the pipe sizes. However, in an embodiment, the plate or band is flexible and can bend about pipes of various diameters. For instance, the clamp may be used to patch fire mains ranging from 4 to 8 inches in diameter. In another application, the clamp may be used for patching a rupture of a transfer pipe of any industrial, scientific or commercial applications including petrochemical plants, water treatment plants, chemical plants and alike. 
     The patch may also include a sealing medium on the inside face of the patch to assist in creating a liquid or fluid tight seal when fitted to a pipe. 
     The sealing medium may be any suitable material depending on the particular application and the fluid being transported in the pipe. In the situation in which the fluid being handled is water, suitably the sealing medium is a rubber or polymeric based material. In the instance in which the fluid being handled is a hydrocarbon such as oil, suitably the sealing material is a Teflon™. 
     In the situation in which a patch is a separate component and, therefore, does not form part of the clamp, suitably a patching material can be held to the rupture in the pipe by the strapping or the tensioning device of the clamp. Similarly, even in the situation in which the patch forms a part of the wrapping assembly, it is possible for additional extraneous material to be located between the patch and rupture of a pipe, for example, to improve the seal between the patch and external wall of the pipe. 
     In an embodiment, the strapping is releasably connected to the patch. The releasable connection may be formed by any suitable mechanism but is suitably in the form of co-operating male and female components, and even more suitably in the form of a peg extending outwardly from the patch and a ring formation on the strapping that releasably receives the peg. 
     When the strapping is released from the patch, the clamp can be readily fitted over a pipe and reconnected to encircle the pipe. The adjustment device is then operable to adjust the wrapping assembly and the tensioning device about the pipe. 
     In the situation in which the clamp does not include a patch, the wrapping assembly may be releaseably connected to the tensioning device, for example by buckles, to allow the clamp to be installed about the pipe. 
     In an embodiment, the clamp comprises only one wrapping assembly and only one tensioning device. In an alternative embodiment, the clamp may comprise two or more wrapping assemblies that may or may not be interconnected and each wrapping assembly has a tensioning device. The wrapping assemblies may be interconnected by one or more patches or plates. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the present invention will now be described by way of example with reference to the accompanying drawings, of which: 
         FIG. 1  is left perspective view of a clamp according to a preferred embodiment that is in the process of being fitted to a pipe comprising of three interconnected clamping assemblies, each having a lever handle that is located in an unloaded neutral position; 
         FIG. 2  is a right perspective view of the clamp shown in  FIG. 1 ; 
         FIG. 3  is end view of the clamp shown in  FIG. 1 ; 
         FIG. 4  is the same view of the clamp shown in  FIG. 1  save for the clamp being located in a loaded working position; 
         FIG. 5  is the same view of the clamp shown in  FIG. 2  save for the clamp being located in a loaded working position; 
         FIG. 6  is the same view of the clamp shown in  FIG. 3  save for the clamp being located in a loaded working position; 
         FIG. 7  is a left perspective view of two clamps fitted side-by-side to a curved pipe according to another preferred embodiment, each clamp comprising a handle lever that is located in an unloaded neutral position; 
         FIG. 8  is a right perspective view of the clamps shown in  FIG. 7 ; 
         FIG. 9  is an end view of the clamps shown in  FIGS. 7 and 8 ; 
         FIG. 10  is a perspective view of a part of the embodiment of the clamp shown in  FIGS. 7 to 9 ; 
         FIG. 11  is a perspective view of a part of the embodiment of the clamp shown in  FIGS. 1 to 6 ; 
         FIG. 12  is a side view of an alternate part that could be used on the embodiments shown in  FIGS. 1 to 9 ; 
         FIG. 13  is a schematic underneath view of a clamp according to another embodiment being fitted to a pipe, the clamp comprising of three wrapping assemblies each including a disconnected strap and a tension device in the form of an over centre lever mechanism comprising a pivoting handle located in a unloaded neutral position; 
         FIG. 14  is the schematic view shown in  FIG. 13  with the straps connected to a base plate of the wrapping assembly; 
         FIG. 15  is the schematic view shown in  FIGS. 13 and 14  wherein the straps have been manually tightened and wing nuts on the handle tightened in the direction of the arrow; 
         FIG. 16  is the schematic view shown in  FIGS. 13 to 15  wherein the handle is in the process of being pivoted in the direction of the arrow into a loaded working position; 
         FIG. 17  is the schematic view shown in  FIGS. 13 to 16  wherein the handle is located in the loaded working position; 
         FIG. 18  is a schematic underneath view of a clamp according to another embodiment being fitted to a pipe, the clamp comprising of three wrapping assemblies each including a disconnected strap and a tension device in the form of an over centre lever mechanism comprising a pivoting handle located in a unloaded neutral position; 
         FIG. 19  is the schematic view shown in  FIG. 18  with the straps connected to a base plate of the wrapping assembly and wing nuts on the handle tightened in the direction of the arrow; 
         FIG. 20  is the schematic view shown in  FIGS. 18 and 19 , wherein the handle is in the process of being pivoted in the direction of the arrow into a loaded working position; and 
         FIG. 21  is the schematic view shown in  FIGS. 18 to 20 , wherein the handle is located in the loaded working position and the straps fitted to an end of the handles to prevent the handles from being unintentionally moved from the loaded working position to a neutral unloaded position. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 to 3  illustrate three separate views of a single clamping device fitted to a pipe comprising three wrapping assemblies, each having a lever handle that is located in an unloaded neutral position in which the clamp is loosely fitted around the pipe.  FIGS. 4 to 6  illustrate the same views of the device shown in  FIGS. 1  to  3 , save for the lever handles being pivoted into a loaded working position. The device shown in  FIGS. 1 to 3  and the device shown in  FIGS. 4 to 6  therefore comprise the same features and for the purpose of the complete description of the device, it is only necessary to describe the device in detail with reference to  FIGS. 1 to 3 . The same reference numerals have been used on  FIGS. 4 to 6  to label the same features of the device in  FIGS. 1 to 3 . 
     Although the components of the device have been allocated a reference numeral in the following text, in order to maintain clarity of the Figures, all of the components have not been labelled with its respective reference numeral in every Figure. However, the reference numerals used in the text are shown in at least one of the Figures. 
     The clamp comprises a wrapping assembly in the form of a resiliently flexible base plate  20 , looped straps  21  with an adjustment device in the form of a clasp  22 , and an over centred lever mechanism  23 . As best seen in  FIGS. 13 to 17 , the clamp is initially fitted to a pipe  24  of any size by disconnecting the straps  21  from the base plate  20  and placing the plate  20  over the rupture  25  in the pipe  24  in the manner shown in  FIG. 13 , the straps  21  are then connected to the base plate  20  as shown in  FIG. 14  and the free ends of the straps  20  pulled so as to fit the clamp around the pipe, and thereby provide a coarse level of adjustment. Adjustable wing nuts  26  on the over centre lever mechanism  23  can then be adjusted in the direction of the arrow shown in  FIG. 15  to provide a finer level of adjustment of the clamp. 
     As shown in  FIGS. 15 to 17 , the over centre lever mechanism  23  can be pivoted in the direction of the arrow shown in  FIG. 16  from an unloaded neutral position to a loaded working position whereby the assembly is held taught around the pipe  24 . In the event that leakage from the rupture  25  in the pipe  24  is inadequately sealed by the clamp, the lever mechanism can be released and finer adjustment of the wing nuts  26  can be undertaken followed by movement of the handles back into a loaded working position. 
     The preferred embodiment shown in  FIGS. 1 to 3  comprises a single flexible base plate  20  which is connected to three straps  21  and three over centre lever mechanisms  23 .  FIG. 11  shows a perspective view of the plate  20  in isolation which forms part of the clamp shown in  FIGS. 1 to 6 . As can be seen, at the lower end of the plate  20 , three pegs  27  protrude outwardly and each of the pegs  27  has an upwardly facing U-shape formation  28 . The opposite upper edge of the plate  20  comprises three saddle formations  29  to which a handle  30  of the over centre lever mechanism  23  is pivotally mounted. The strapping includes a D-shaped formation  31  which can be connected and disconnected from each of the pegs  27  as desired. The layout of the strapping is such that the strapping extends from the clasp  22  to the D-shaped formation  31  through which it is threaded, and then looped back over a linkage  32  inter-connecting the strapping  21  to the lever mechanism  23  and then finally through the clasp  22 . The clasp  22  includes a spring loaded flap  34  that is biased toward an abutment rod  33  which extends across the width of the clasp  22 . The end of the flap  34  and the abutment rod  33  are arranged such that tension in the strapping  21  causes the flap  34  of the clasp  22  to move toward the abutment rod  33 , thereby wedging the strapping  21  between the flap  34  and the abutment rod  33 . When the device has been fitted over a pipe  24  as shown in  FIG. 13 , the D-shaped formation  31  can be fitted to the pegs  27  of the plate  20  and the free end of each strapping  21  can be pulled to adjust the effective length of the strapping  21  wrapping about the piping  24  to a desired tension. In order to lengthen the loops of strapping and, in turn the effective length of the strapping  21  about the piping  24 , the flap  34  is lifted to allow the strapping  21  to slide through the clasp  22 . It would be appreciated that the clasp  22  and strapping  21  thereby provide a coarse level of adjustment for fitting the device to pipe  24 . 
     The handle  30  of the lever mechanism  23  has a V-shape that is pivotally mounted to the saddle formation  29  on the base plate  20  at pivot point  42 . The V-shaped handle  30  comprises a major limb  30   a  which provides a grip by which the lever is operated and a minor limb  30   b  having a compartment in which an adjustor in the form of a screw threaded shaft  40  is slidably housed. Either side of the compartment has a slot  38  and ends of the linkage arms  36  are aligned with a fastening bolt  39  that extends through holes in the ends of a linkage arms  36 , the slots  38  and holes in the screw threaded shaft  40 . The fastening bolt  39  defines an axis about which the linkage arms  36  are pivotally connected to the lever  23  and, in particular, to the minor limb  30   a  thereof. A butterfly or wing nut  26  is fitted to an outside end of the screw threaded shaft  40  such that rotation of the wing nut  26  can move the pivot connection defined by the bolt  39  between the linkage arms  36  of the screw threaded shaft  40  in a direction along the slots  38  of the minor limb  30   b  of the handle  30 . In other words, rotation of the wing nut  26  moves the pivot connection between the minor limb  30   b  of the lever  23  and the linkage arms  36  either towards or away from the pivot point  42  of the lever  23 . In order to increase the tension of the clamp around the pipe, the wing nut  26  is rotated to move the pivot connection defined by bolt  39  in a direction away from the pivot point  42  of the lever  23 . Conversely, in order to loosen the pressure of the clamp around the pipe  24 , the wing nut is rotated so as to move the pivot connection defined by bolt  39  in a direction toward the pivot point  42  of the lever  23 . It would be appreciated that the adjustable nature of the pivot connection between the linkage arms  36  and the lever  23  provides a second and finer level of adjustment of the tension of clamp about the pipe  24 . 
     The pairs of linkage arms  36  are connected to each strapping  21  via a cam body  35  and linkage  32 . In particular, each pair of linkage arms  36  are pivotally mounted to the cam body  35  via a fastening bolt that defines a pivot axis  37 , which is best seen in  FIGS. 3 and 6  as extending through an upper portion of the cam body  35 . 
     The linkage  32  essentially comprises two plates that are pivotally connected to the cam body  35  via a fastening bolt that defines a pivot axis  47 . A further fastening bolt at the opposite end of the plates defines an axis  57  about which the strapping  21  is located. As can best be seen  FIGS. 3 and 6 , the pivot axis  37  of the linkage arms  36  to the cam body  35  extends through the cam body  35  at a spacing from piping  24  that is greater than the spacing of the pivot axis  47  the piping  24 . 
     As can be best seen in  FIG. 6 , each linkage arm  36  is curved such that when the lever  23  is located in a loaded position, the linkage arms  36  extend over the pivot point  42  at which fastening bolt pivotally mounts the lever  23  to the saddle formation  29  on the base plate  20 . 
     In addition, each linkage arm  35  is pivotally connected to the cam body  35  at pivot axis  37  that is displaced from the pipe  24  to reduce the degree of curvature and/or length of the linkage arms  35  that would otherwise be required. 
       FIG. 3  illustrates an end view of the clamp in which the lever  23  is located in an unloaded neutral position in which the wrapping assembly comprising base plate  20  and straps  21  are located in an initial circumferentially expanded state about the pipe  24 . In other words, the straps  21  have been fitted and adjusted to an initial tension. In order to put the clamp in a working condition, the lever  23  is pivoted in the direction of the arrow shown in  FIG. 3 , so as to locate the lever  23  into a loaded working position as shown in  FIGS. 4 to 6 . As can best been seen in  FIG. 6 , when the lever  23  is located in a loaded working position, the wrapping assembly comprising base plate  20  and straps are located in a circumferentially contracted state about the pipe  24 . As described above, the wing nuts  26  enable the size of the circumferentially contracted state of the clamp  23  about the pipe  24  to be gradually or progressively adjusted. 
     In moving the lever  23  in the direction of the arrow into the loaded working position, the lever passes through a peak load or tension position before reaching the loaded working position to provide an over centre effect. The over centre effect helps retain the lever mechanism in the loaded position and in order to move the lever into an unloaded position, an operator is required to move the lever  23  from loaded working position into a direction work the unloaded neutral position. 
     In addition to the above, it will be appreciated that the inside face of the base plate  20  may comprise any suitable material  43  for forming a seal with a rupture in the pipe. 
       FIGS. 7 to 9  illustrate another preferred embodiment of the present invention. In particular  FIGS. 7 and 8  illustrate two clamps fitted to a pipe, wherein each clamp comprises a single base plate  20 , a strap  20  with locking clasp  22  and a tensioning device in the form of an over centred lever mechanism  23 . All of the features of the clamp shown in  FIGS. 7 to 9  are substantially the same as the features of the clamps shown in  FIGS. 1 to 6  save for each wrapping assembly comprising a single base plate  20  rather than a continuous base plate  20  interconnecting three straps  21 . In summary, in addition to the base plate  20 , each clamp comprises looped strapping  21  with an adjustment device in the form of a claps  22  and an over centre lever mechanism  23 . The strapping  21  is releasably attached to the base plate via a peg  27  on the base plate  20  and a D-shaped formation  31  that defines an end of the strapping  21  about which the strapping is looped in a U-shape. The over centre lever mechanism  23  includes a handle  30  having a V-shape that is pivotally mounted to the base plate  20  at pivot point  42  by a saddle formation  29  and bolt. The V-shaped handle includes a major limb  30   b  and minor limb  30   a  having an internal compartment in which a screw threaded shaft  40  having a butterfly wing nut  26  is fitted. The screw threaded shaft is pivotally connected to ends of a pair of curved linkage arms  36  and the other ends are connected to the cam block  35 . The cam block  35  is connected to the straps  32  via a linkage  32 . Operation of the clamp shown in  FIGS. 7 to 9  is substantially the same as described with reference to the embodiment shown in  FIGS. 1 to 6 . 
       FIG. 10  is a detailed view of the base plate  20  which comprises one of the pegs  27  for receiving the D-shaped ring of the strap  21  and one of the saddle formation  29  for pivotally mounting the lever mechanism. The inside face of each base plate  20  may comprise a sealing medium or alternatively, and in a situation in which multiple clamping devices are fitted to one pipe, an additional sealing medium  46 , as best seen in  FIGS. 8  and  9 , may extend between separate installations of the clamping device. 
       FIG. 12  is a side view of a base plate  20  having an alternative peg formation  27 . Specifically, the peg formation  27  has a leading ramp over which the D-shaped formation  31  can slide prior to being received by the recess  28 . The leading ramp may have a rounded outer profile as shown in  FIG. 11 , or alternatively a progressively tapering profile. 
       FIGS. 18 to 21  illustrate yet another embodiment that is the same, save for one major difference, as the embodiment shown in  FIGS. 1 to 6  and  14  to  17 . The notable difference is the inclusion of a locking mechanism for selectively locking the handle  30   a  in a loaded working position. When locked, the locking mechanism prevents the handle  30   a  from moving and being inadvertently or unintentionally released in a direction opposite to the direction of the arrow shown in  FIG. 20 . 
     In the case of the embodiment shown in  FIGS. 18 to 21 , the locking mechanism is in the form of a strap  51  that is a continuation or extension of the strapping  21 . In practice, the strap  51  is fitted to the end of the handle  30   a  and tensioned to prevent movement of the handle  30   a . Suitably, the locking mechanism also includes a clasp  52  to which the strap  51  is adjustably secured. The clasp  52  includes an eyelet formation which can be placed over the end of the handle  30   a  which may also have a corresponding lip to help retain the clasp  52  and strap  51  in position on the end of the handle  30   a . Like the clasp  22 , the clasp  51  also includes a releasable flap and an abutment surface between which the strap  51  slides by pulling on the free end of the strap  51  to tension the strap  51  between the clasps  22  and  51  and thereby lock the handle  30   a  in the loaded working position. The locking mechanism is released by opening up the flap of the clasp  51 . 
       FIGS. 18 and 19  illustrate a sequence of steps involving positioning the clamp on a pipe and securing the D-shaped formations  31  to the pegs  27  of the base plates  20 . The strapping  21  then undergoes initial tensioning by sliding the strapping  21  through the clasp  22 . In addition, the wing nut can be rotated as shown in the  FIG. 18  to adjust the purchase provided by the over centre lever prior to engaging the lever. The lever, and in particular, the handle of the lever is moved in the direction shown by the arrow in  FIG. 19  to place the clamp into a loaded working position on the pipe. Finally as shown in  FIG. 20 , the clasp  52  is placed in the end of the handle  30   a  and the free end of the strap  51  pulled to tension the strapping  52  between the clasps  22  and  51 , and thereby lock the handle  30   a  in a loaded working position until the flap of the clasp  52  is opened. 
     Although it is possible that each of the components of the clamping device may be made of a specialised material to facilitate the function of each component, it is envisage that the entire clamping device may be made from 316 grade stainless steel. 
     The preferred embodiments provide a number of advantages over clamping devices presently available such as the following.
         The clamp does not require an inventory of consumable and one use only components. Rather, the preferred embodiments are temporarily fitted, and thereafter removed and then reused to temporarily patch another rupture at a future time.   The clamp comprises two levels of size adjustments, namely coarse and fine level adjustment such that the clamp can be readily used in different applications and for sealing different pressure pipelines.   The clamp does not require cutting strapping either during installing or during removal of the clamp and, therefore, does not possess the inherent risks associated with exposed edges of cut strapping.   The clamp is capable of being fitted to a range of pipe sizes including pipelines 4 to 6 inches in diameter. The clamp may also be fitted to pipes of other diameters and may be scaled up and down accordingly.   Moreover, the clamp is adapted to be fitted in emergency situations and in the shortest possible time frame.       

     Those skilled in the art of the present invention will appreciate that many variations and modifications may be made to the preferred embodiments without departing from the scope of the present invention. 
     In the claims which follow and in the proceeding description of the invention, except where the context requires otherwise due to expressed language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense i.e. to specify the presence of stated features but not to preclude the presence of addition or further features in various embodiments of the invention.