Abstract:
A clamp for securing a pipe to a supporting structure and including a base having a foot for attachment to a supporting structure and a head having a seating for accommodating a pipe and two walls for defining the seating, an entrance for the pipe extending between the two walls, and an U-formed strap for clamping a pipe placed in the seating to the base. The strap has two legs for engaging opposite contact faces formed in the base and a curved bottom for surrounding the pipe together with the walls of the head. The radius of curvature of the inner side of curved bottom of the U-formed strap is larger than that of the seating. The clamp enables a secured pipe to noiselessly expand or contract depending upon the temperature and is mainly corrosion free due to the clearance that is formed between the strap and the clamped pipe.

Description:
This application is a 371 filing of International Patent Application PCT/EP2009/054714 filed Apr. 21, 2009. 
     BACKGROUND 
     The invention relates to a clamp for securing a pipe to a supporting structure like for example a wall in a building. 
     The clamp comprises a base with a foot for being attached to the supporting structure and a head with a seating for in use accommodating a pipe, two walls of the head defining the seating, an entrance for the pipe extending between the two walls, and an U-formed strap for clamping a pipe placed in the seating to the base whereby the strap is having two legs equipped each with a hook for in clamping position engaging opposite contact faces in cavities formed in the foot of the base and a curved bottom for at the same time surrounding the pipe together with the walls of the head. 
     The term pipe is standing here for an elongated element like a cable, a solid bar, or a pipe like a water pipe, a heating pipe ore a gas pipe. 
     Pipes are frequently secured to e.g. walls in buildings by means of clamps placed in positions where they risk to be destroyed more or less by accident or vandalism. It therefore is required that the clamps have a construction, which is strong and strenuous to separate. 
     Another problem consists in the fact that a pipe, which often can be relatively long, expands and contracts with varying ambient temperature and/or the temperature of the medium flowing in the pipe whereby the clamps will be exposed to alternating crosswise acting forces. The clamps therefore should be arranged for being securely and stable attached to the wall. 
     The clamps also need to be able quickly and easily to securing the pipe to the wall since many clamps frequently are used for installing often-large quantities of pipes required in a building. 
     Of the same reason the clamps also should have an inexpensive construction. 
     From the patent FR No. 1.477.777 is known a clamp for securing a pipe to a wall. The clamp has a base with a seating for the pipe and a semicircular strap, which spans the pipe when being attached to the base by means of two hooks engaging each their slit in the top of the thin wall around the seating. The hooks are straight and short and the depth of the cooperating slits is little. The connection between the strap and the base therefore is extremely weak already of that reason. The hooks moreover easily disengage the slits by accidentally or intended opening the strap owing to the semicircular shape of this. 
     Another problem consists in the fact that the bearing face of the base has a very little area with the result that the securing of the base and thereby of the pipe to the wall will be week and unreliable. 
     A similar construction is disclosed in the publication GB 1,076,683. The strap is in this case attached to the base by means of dovetail projections engaging dovetail shaped recesses formed in the base. According to this publication is the strap secured to the base by first flexing apart the arms of the strap and then let the projections snap into engagement with the recesses. That means obviously that the engagement should take place in a sideways movement of the projections into the recesses by using only the spring force of the relatively thin strap. The spring force of the strap is however relatively little owing to the arched shape of the strap. The projections therefore easily disengage the recesses by accidentally or intended opening the weak strap. The bearing face of the base has a large extension crosswise the pipe but a little extension into the axial direction of the pipe. That implies that securing of the base and thereby of the pipe to the wall will be unreliable into the axial direction of the pipe where the clamps in dependence of the varying temperatures of the pipe are exposed to alternating crosswise acting forces. This known clamp has a complicated and costly construction, which moreover is laborious and time-consuming to use for fitting a pipe to a support structure. 
     Similar clamps are known from the documents, DE 77 10 649 U1, DE 86 28 193 U1, FR 1 477 777 A, FR 2 044 993 A and GB 268 497 A. 
     Common for these known techniques and the techniques of the documents previously mentioned are however that they are somewhat noisy in use and also tend to corrode. 
     The above-mentioned disadvantages of the prior art clamps for securing a pipe to a supporting structure like for example a wall in a building are according to the present invention remedied by, 
     in a first aspect of the invention providing a clamp with a construction which allows the secured pipe mainly noiseless to expand or contract in dependence of varying temperatures, 
     in a second aspect of the invention providing a clamp with a corrosion free construction, 
     in a third aspect of the invention providing a clamp which have a strong and stable construction, 
     in a fourth aspect of the invention providing a clamp which have a construction which is strenuously to separate, 
     in a fifth aspect of the invention providing a clamp arranged for being securely and stably attached to a supporting structure, 
     in a sixths aspect of the invention providing a clamp able to quickly and easily securing the pipe to a supporting structure, 
     in a seventh aspect of the invention providing a clamp having a simple and inexpensive construction, 
     in a eight aspect of the invention providing a clamp having a durable construction, 
     in a ninth aspect of the invention providing a clamp with a construction which allows the secured pipe mainly noiseless to expand or contract in dependence of varying temperatures, 
     SUMMARY OF THE INVENTION 
     in a tenth aspect of the invention providing a clamp which has a nice appearance. 
     The novel and unique features of the invention whereby these features are achieved consists in the fact that the distance from the centre of the seating to the inner side of the curved bottom of the U-formed strap is larger, seen in the clamping position of the strap, than the radius of curvature of the seating. 
     Thereby is according to the invention advantageously obtained that a pipe placed in the seating noiseless or at least with a minimum of noise is allowed to expand or contract axially in dependence of varying temperatures while axially sliding in the clamp especially when the base is made of an elastic material like a ductile material as e.g. polypropylene so that the head of the base easily can follow the concurrent changing of the cross section of the pipe. 
     Another advantage according to the invention consists in the fact that galvanic corrosion between a strap of e.g. steel and a pipe of e.g. copper or brass can be avoided when the two metals is without any contact with each other. 
     Conventionally is the strap clamping the pipe to the base by pressing the pipe against the seating of the base resulting in that a reaction force from the pipe is acting upon the strap. 
     Said reaction force produces an essential friction between the pipe and the strap rocking the strap around the point where the hooks of the strap is engaging the foot of the base because the pipe expands and contracts with the temperature whereby the clamp will destroy itself in the course of time. 
     This serious problem is remedied by using the clamp of the invention since the strap in this case is not as conventionally pressing the pipe against the base but on the contrary is clamping the base to the pipe without even touching this. 
     According to the invention can the curved bottom of the U-formed strap be acting onto the walls of the head with a pipe in the seating so that the pipe tightly is clamped between said walls by bending the walls. 
     Each wall of the head of the base can according to the invention be formed with elasticity and bending strength allowing such bending of the walls. 
     When the walls is tapering against the entrance to the seating is according to the invention moreover advantageously achieved that the bending strength decreases into the direction of the top of the walls so that the pressure of the walls upon the pipe gradually increases and the pipe thereby advantageously is acted upon by downwards directed components of forces when the width of the entrance is smaller than the diameter of the pipe. This construction implies that the base securely can be clamped to the pipe. 
     The strap can according to the invention be made of a band of metal and be stressing the walls of the head with the forces necessary for bending the walls of the head tightly round the pipe whereby the curved bottom of the strap is acted upon by the reaction of these forces. 
     The curved bottom of the U-formed strap therefore according to the invention can have a bending strength large enough to prevent the bottom to be deflected more than the clearance to a pipe clamped to the base when being exposed to the action of the reaction of the forces stressing the walls. 
     In a preferred embodiment of the invention can the base be formed with two opposite sides extending crosswise to the seating whereby the strap can have a width corresponding to the distance between those sides. 
     The clamp thereby is achieving a nice appearance simultaneously with that the strap is forming a protecting cover over the base, which may be of a softer material like e.g. polypropylene while the strap may be of a harder material like e.g. stainless steel. 
     The width of the hooks of the strap can moreover be lesser than the width of the remainder of the strap whereby advantageously is obtained that the strap is fixed against being displaced in the longitudinal direction of the pipe. 
     The foot of the base of the clamp can according to the invention have bearing face with a relatively large area so that the clamp securely and stable can be attached to a supporting structure for the pipe. 
     Said attachment of the pipe to the supporting structure can according to the invention moreover easily and quickly be performed by means of one or more fasteners like e.g. screws passed through associated bores in the base. 
     Each hook of the strap can according to the invention furthermore be formed as a V with apex pointing toward the curved bottom of the U-formed strap whereby the contact face for engaging the hook can be formed with a projection so that the hook accidentally or intended is very difficult and strenuous to separate from the base and that the clamp therefore is hard to destroy. 
     In a preferred embodiment according to the invention can the outer sides of the head and foot of the base be merging tangentially into each other at the same side of the seating so that the strap easily can be attached upon the base when clamping a pipe. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in greater details below where further advantageous properties and example embodiments are described with reference to the drawings, in which 
         FIG. 1  is a perspective view of a base of a clamp of the invention, 
         FIG. 2  is a perspective view of a strap to the clamp of the invention, 
         FIG. 3  is an exploded view of a lateral cross section taken across a pipe to be secured to a supporting structure, including the strap seen in  FIG. 2 , the pipe, a fastener for securing the clamp to the supporting structure, and the base seen in  FIG. 1 , 
         FIG. 4  shows the assembling of the parts shown in  FIG. 3  secured to the supporting structure, 
         FIG. 5  is an exploded view of a lateral cross section of the parts shown in  FIG. 3 , but taken along the pipe, 
         FIG. 6  shows the assembling of the parts shown in  FIG. 5  secured to the supporting structure, 
         FIG. 7  is a lateral view of a fragment of a cross section of the strap shown in  FIG. 2 , 
         FIG. 8  is a lateral view of a fragment of a cross section of the base shown in  FIG. 1 , and 
         FIG. 9  shows the assembling of the strap and base shown in  FIGS. 7 and 8 , respectively. 
     
    
    
     The following detailed description of the invention is by way of example based on the assumption that the clamp of the invention is a heating pipe and that the supporting structure for the pipe is a supporting wall in a building. 
       FIGS. 1 and 2  shows an exploded view, seen in perspective, of the clamp  1 , which as seen comprises a base  2  and a strap  3 . 
     DETAILED DESCRIPTION OF THE INVENTION 
     The base consists of a foot  4  for securing the base to the wall (not seen) by means of a fastener like e.g. a screw (not seen) and of a head  5  for securing the pipe (not seen) to the base by means of a traversing seating  6  for accommodating the pipe. 
     The seating  6  is partly surrounded by walls  7  of the head whereby the walls are limiting an entrance  8  for allowing the pipe to be passed into the seating. 
     The width of this entrance is smaller than the diameter of the pipe so that the wall is surrounding the pipe along an angle of an arch of more than 180 degrees. 
     The base and thereby said walls of the head is made of a ductile material like e.g. polypropylene causing the walls round the seating to be able to flex. 
     The entrance to the seating therefore temporary can be expanded sufficiently to allow the pipe to pass into the seating. The walls round the seating can moreover flex in accordance with the varying diameters of the pipe, which will expand or contract in dependence of the temperature of the pipe. 
     The capability of the walls round the seating to flex is moreover improved by tapering the walls  7  of the head  2  against the entrance  8  to the seating  6 . 
     The shape of the base  2  is in the main formed like an obelisk with opposite outer sides  10  of the head  5  tangentially merging into opposite sides  12  of the foot  4  whereby a large bearing face  14  for the base is achieved for securely and stable attaching the base to the supporting wall of the building. 
     The obelisk formed shape of the base also is imparting a strong and durable structure to the base and a very nice appearance to the clamp. 
     The strap  3  is in the present embodiment made of an elastic band of metal, e.g. stainless steel. The elasticity of the metal makes the strap able to flex sufficiently. Using a material like stainless steel implies that the strap will be strong even if the band of metal is thin. 
     The strap is arranged for being secured to the base and in secured state to cover the entrance to the seating in which a pipe is placed. 
     The strap  3  is for that purpose formed as a U with a curved bottom  15  for covering the entrance  8  to the seating  6  and two legs  16  equipped with hooks  17  for securing the strap to the base by engaging opposite contact faces  18  in cavities  19  formed in the base  2 . 
       FIG. 3  is an exploded view of a cross section of the clamp comprising the elastic strap  3 , a pipe  20 , a screw  21  and the base  2 . The cross section is taken across the pipe. 
       FIG. 5  shows the same parts  3 ,  20 ,  21  and  2  as seen in  FIG. 3  but in a cross section taken along the pipe  20 . 
     In the foot  4  of the base  2  is formed a first bore  22  extending from the seating  6  in the head  5  and a second bore  23  extending from the first bore  22  to the bearing face on the foot  4 . 
       FIG. 4  shows the assembling of the parts shown in  FIG. 3  secured to a supporting wall  24 , and  FIG. 6  shows the assembling of the parts shown in  FIG. 5  secured to the supporting wall  24 . 
     The pipe  20  is quickly and easily attached to the supporting wall  24  by means of the clamp according to the invention in the following way. 
     The foot  4  of the base  2  is placed on the supporting wall  24  with its bearing face  14  bearing against said wall. The screw then is passed through the bores  22  and  23  in the foot and screwed into the wall. Other types of fasteners can within the scope of the invention be used instead of a screw. 
     The pipe  20  then is pressed into the seating  6  for the pipe through the entrance  8  in the flexible wall  7  of the head  5  of the base  2 . The pipe  20  now is firmly anchored in the base  2 . 
     Afterwards is the flexible U-formed strap  3  pressed across the base until the hooks  17  of the strap snap into the cavities  19  in the foot  4  of the base  2  and engage the contact faces  18  in the cavities  19 . 
     This operation is easy to perform owing to the large flexibility of the material of the strap and to the fact that the opposite outer sides  10  of the head  5  tangentially are merging into the opposite sides  12  of the base  2  so that the hooks is allowed to slide over the smooth transition between said sides  10  and  12  without any hindrance. 
     The pipe  20  is now, as shown in  FIG. 4  and  FIG. 6 , stably secured to the clamp  1  while the clamp itself stably is secured to the support wall  14 . 
     This construction is strong and also strenuously to separate, since the bore  22 , 23  with the screw  21  is concealed by the pipe and the hooks are locked by the engagement with the contact faces in the cavities. 
     The pipe slides, as previously mentioned, in the clamp because the pipe expands or contracts in dependence of varying temperatures of the pipe. Sliding along the base, which is made of a ductile material like e.g. polypropylene doesn&#39;t generate noise of any importance, but sliding along the strap, which is made of e.g. stainless steel, would generate inconvenient noise. 
     The bottom  15  of the strap  3  therefore is formed in such way that a clearance  25  is formed between the strap  3  and the pipe  24  so that the strap is not able to touch the pipe. 
     No noise at all then can be generated since the strap now doesn&#39;t touch the pipe. 
     Another advantageous consists in the fact that galvanic corrosion between a strap of e.g. spring steel and a pipe of e.g. copper or brass cannot arise when the two metals is without any contact with each other. 
     Instead is the curved bottom  15  of the U-formed strap  3  bearing against the outside of the head  5  of the base  2  at areas adjacent to the entrance  8  to the seating  6 . This feature implies advantageously that the tapering walls of the head are firmly tightened about the pipe  20  in the seating  6 . 
     The legs  16  of the U-formed strap  3  are straight and therefore able to transmit a large force from the curved bottom  15  of the strap  3  to the hooks  17 . 
       FIG. 7  shows in a larger scale a fragment of the strap  3 . The hook  17  of the strap is formed as a V with apex  26  pointing toward the curved bottom (not seen) of the U-formed strap. 
     The V has a first side  27  connected to the leg  16  of the strap and a second side  28  connected to the first side  27  only. 
       FIG. 8  shows in a larger scale a fragment of the foot  4  of the base. The contact face  18  for engaging the hook  17  is at the entrance to the cavity  19  in the foot  4  formed with a projection  29 . 
     The hook  17  is in  FIG. 9  snapped into the cavity  19  as the leg of the strap  3  and the hook  17  itself is able to flex sufficiently for allowing the hook to pass the projection  29  on the contact faces  18  in the cavity  19 . 
     The second side  28  of the V is effectively contributing to the flexing of the hook since this side of the V is the first part of the strap, which is engaging the projection  29  on the contact face  18 . 
     The pipe will in use tend to slide along the strap owing to the fact that the length of the pipe is changing with varying temperatures whereby inconvenient noise is generated when the pipe is of metal like e.g. stainless steel. A clearance therefore is arranged between the strap and the pipe so that the strap cannot touch the pipe. 
     As seen in  FIG. 9  is the projection  29  securely locking the hook  17  to the foot  4  by engaging a groove  30  formed in the first side of the hook. The hook now is extremely difficult to disengage from the contact face  18 . 
     The width of the strap  3  corresponds to the width of the base  2 , but as best seen in  FIGS. 1 and 2  has the cavity  19  in the foot  4  of the base  2  and the hook  17  on the strap  3  a width, which is smaller than the width of the foot and the strap. 
     Thereby is advantageously obtained that the strap is secured against being displaced sideways on the base, which is into the axial direction of the pipe. The strap therefore cannot be released from the base by sideways displacement on the base. 
     In the embodiment of the invention shown in  FIG. 2 , in which the strap particularly easy and quickly can be mounted upon the base, is each hook moreover tapering into the direction outwards from the respective leg of the strap whereby advantageously is achieved that the strap automatically becomes self-centering by being mounted to the base. 
     In another embodiment of the invention (not shown) is the base secured to the supporting wall by means of a stud screw fastened to the supporting wall and a screw nut formed in the base or alternatively by means of a screw nut fastened to the supporting wall and a stud screw formed on the base. The base then is secured to the support wall by being screwed onto the stud screw or the screw nut, respectively. 
     By means of the construction described above of the clamp according to the invention is thus provided a strong and stable clamp, which is easy to fit and strenuously to separate and which moreover has a nice appearance. 
     The invention is above described on the assumption that the clamp of the invention is a heating pipe and that the supporting structure for the pipe is a supporting wall in a building. 
     The clamp can however within the scope of the invention just as well be used for securing any other elongated elements like for example cables and solid bars to a supporting wall in a building, and the supporting wall could be any other supporting structure like for example a ceiling in a building or a wall or ceiling in a ship.