DEVICE FOR THE COUPLING TOGETHER OF PIPES

Abstract: A device for coupling together pipes, which at their end have an outwardly directed bead, comprises an annular clamping strap (1) and a clamping mechanism (4-6) arranged at the ends (2a, 2b) of the clamping strap. Between the ends (2a, 2b) of the clamping strap (1), a sealing element (7) is arranged for sealing the joint between the ends (2a, 2b).

Description: DEVICE FOR THE COUPLING TOGETHER OF PIPES Field of the Invention The present invention relates to a device for coupling together pipes which at their end has an out ¬ wardly directed bead. More specifically, the invention concerns a device of the type as stated in the preamble to claim 1 , which is based on a clamping strap according to Danish Utility Model Specification No. 94 00346. B ackground of the Invention Such a known clamping strap is usually provided with a clamping mechanism, which may consist of, for instance, a screw which is passed through the outwardly bent ends of the clamping strap and which is screwed into an abut ¬ ment member in the form of a nut or the like. This clamp ¬ ing strap, which in fact functions well, sometimes suf- fers from a drawback in the form of insufficient sealing in the joint between the two ends of the clamping strap. Pipes, to which the invention is applicable, are disclosed in e.g. the brochure "Circular Duct System", LindabTransfer, from 1992, issued by Lindab Ltd, as well as in WO 94/12295. Prior-art pipe couplings, which have a certain sealing function and which may be mentioned as examples of prior art, are disclosed in US-A-3, 479,066 and DE-A-25 17 808. Summary of the Invention The object of the invention is to provide in a sim ¬ ple and inexpensive manner a pipe coupling device, which in relation to prior art has improved sealing capacity, especially in the joint between the two ends of the clamping strap. According to the invention, this and other objects that will appear from the following specification have now been achieved by a device which is of the type as described by way of introduction and which in addition has the features recited in the characterising clause of claim 1. Thanks to the sealing element in the joint between the end portions of the clamping strap, an excellent seal is established when tightening the clamping strap, since the sealing element then abuts closely against the oppo- site end portions of the clamping strap and is clamped therebetween, and also fills the joint therebetween. Further features of the invention are defined in the dependent claims. Brief Description of the Drawing The invention will now be described in more detail with reference to the accompanying drawing, which illu¬ strates an embodiment and in which: Fig. 1 shows a pipe coupling having a clamping strap according to the invention seen in the direction of arrows I-I in Fig. 2, Fig. 2 is a side view of a portion of the clamping strap before the clamping operation, and Fig. 3 shows the clamping strap after the clamping operation. Description of the Preferred Embodiments of the Invention Fig. 1 shows a pipe coupling device according to an embodiment of the invention, comprising an annular clamp¬ ing strap 1 which is U-shaped in cross-section and has two flanges la, lb, which surround circumferential end beads 11, 21 of two schematically illustrated pipes 10, 20. The clamping strap 1 is provided with an internal, circumferentially extending seal 25, which preferably is made of an elastic material, e.g. rubber. For the sake of simplicity, the tubes 10, 20 are not shown in Figs 2 and 3. Fig. 2 illustrates the clamping strap 2 before the clamping operation. The clamping strap 1 has two end por¬ tions 2a, 2b which are bent into part-circular shape and which form pockets, each being formed with an aperture 3a, 3b. The parts of the end portions 2a, 2b facing the joint therebetween have essentially convex surfaces 2a', 2b' . As shown in Fig. 2 as well as in Fig. 3, there is at one end portion 2b a nut-shaped abutment in the form of a first cylindrical element 4 having a threaded hole 4b. In the other end portion 2a, a second cylindrical element 5 is formed, having an unthreaded hole 5a for a straining screw 6. The cylindrical elements 4 and 5 are preferably arranged to be freely rotatable in said pockets. Between the two spaced-apart end portions 2a, 2b there is a sealing element 7 made of an elastic material, preferably rubber. The sealing element 7 is formed with a hole 8, preferably an unthreaded hole. By the sealing element 7 being slipped onto the straining screw 6 through the hole 8, the device will be easy to manufac ¬ ture, while obtaining a very reliable holding of the sealing element 7. The straining screw 6 extends through the aperture 3a in one end portion 2a of the clamping strap 1, through the hole 5a in the cylindrical element 5, further through the hole 8 in the sealing element 7, through the aperture 3b in the opposite end portion 2b of the clamping strap 1 and is finally screwed into the threaded hole 4b of the first cylindrical element 4. The contact surfaces 7a, 7b of the sealing element 7 which are facing the ends of the clamping strap 1, are essen ¬ tially concave in shape corresponding to the convex shape of the respective opposite end surfaces 2a', 2b' of the end portions 2a, 2b. It is also evident that the internal seal 25 has two ends 25a, 25b which are arranged radially inside the sealing element 7. The sealing element 7 preferably has the same width as the clamping strap 1, the width being adjusted to the end surfaces 2a', 2b' of the end portions 2a, 2b. Fig. 3 illustrates the clamping strap 1 after the clamping operation. The sealing element 7 is pressed together and its contact surfaces 7a, 7b engage the opposite end surfaces 2a', 2b' of the end portions 2a, 2b. Thanks to cooperation between the concave contact surfaces 7a, 7b of the sealing element 7 and the convex end surfaces 2a', 2b' of the end portions 2a, 2b of the clamping strap 1, an excellent seal is established in the joint therebetween. During the clamping operation, the two ends 25a, 25b of the internal seal 25 are pressed against the end beads 11, 21 of the pipes 10, 20 by means of the sealing ele¬ ment 7 (cf. Fig. 1). When the pipes 10, 20 are in place, the ends 25a, 25b are of course pressed against the underside of the sealing element 7. The internal seal 27 and the sealing element 7 thus cooperate for additional sealing of the joint between the two end portions 2a, 2b of the clamping strap 1. In an alternative embodiment (not shown), the seal¬ ing element 7 is attached to one of the end portions of the clamping strap. According to a further alternative embodiment (not shown), the internal seal 25 of the clamping strap is a closed, endless seal which cooperates with the sealing element 7 in the manner stated above.

Claims: CLAIMS 1. A device for coupling together pipes (10, 20) having at their end an outwardly directed bead (11, 21), comprising an annular clamping strap ( 1 ) having two oppo¬ site, spaced-apart end portions (2a, 2b) and a clamping mechanism (4-6) arranged in connection with the end por¬ tions of the clamping strap and adapted to tighten the clamping strap round the end beads of the pipes, c h a r a c t e r i s e d in that a sealing element (7) is arranged between the end portions (2a, 2b) of the clamp¬ ing strap ( 1 ) for connection thereto and for sealing the joint therebetween when tightening the clamping strap. 2. The device as claimed in claim 1, wherein the contact surfaces (7a, 7b) of the sealing element (7), which are facing the end portions (2a, 2b) of the clamp¬ ing strap, have a shape which essentially corresponds to the shape of the respective opposite end surfaces (2a' , 2b' ) of the end portions of the clamping strap. 3. The device as claimed in claim 2, wherein said contact surfaces (7a, 7b) are concave, whereas said oppo¬ site end surfaces (2a', 2b' ) are convex. 4. The device as claimed in any one of the preceding claims, wherein the clamping mechanism (4-6) comprises a straining screw ( 6 ) which connects the end portions of the clamping strap with each other and onto which the sealing element (7) is slipped through a hole (8) in the same. 5. The device as claimed in claim 4, wherein the straining screw (6) extends through an aperture (3a) in one end portion (2a) of the clamping strap (1), further through said hole in the sealing element ( 7 ) , through an aperture (3b) in the opposite end portion (2b) of the clamping strap ( 1 ) and is in threaded engagement with an abutment member ( 4 ) in connection with said opposite end portion ( 2b ) . 6. The device as claimed in claim 4 or 5, wherein the hole (8) in the sealing element (7) is an unthreaded hole. 7. The device as claimed in any one of the preceding claims, wherein the clamping strap (8) has an internal, circumferentially extending seal ( 25 ) , which is arranged radially inside the sealing element (7) and with which the sealing element cooperates during said tightening. 8. T he device as claimed in claim 7, wherein the internal seal (25) has two opposite ends (25a, 25b) which are adapted to be pressed against the end beads (11, 21) of the pipes (10, 20) via the sealing element (7) during said tightening. 9. The device as claimed in any one of the preced- ing claims, wherein the sealing element (7) is made of an elastic material, preferably rubber. 10. The device as claimed in any one of the preced¬ ing claims, wherein the sealing element (7) has substan¬ tially the same width as the clamping strap ( 1 ) , prefer- ably the same width as the end surfaces (2a', 2b' ) of the end portions (2a, 2b).

Inventors: ANDERSSON PONTUS, ANDRESEN WERNER, ANDERSSON, PONTUS, ANDRESEN, WERNER
Applicants: ANDERSSON PONTUS, ANDRESEN WERNER, LINDAB AB, ANDERSSON, PONTUS, ANDRESEN, WERNER
Application year: 1996
Main classification: F16L23
IPC codes: F16L23