The invention relates to clamping belts for pipe couplings for the friction-locked connection of pipes, in particular of smooth-end pipes, as well as to pipe couplings for the friction-locked connection of pipes, in particular of smooth-end pipes.
Such pipe couplings, as marketed for example under the brand-name STRAUB-ECO-GRIP® by Straub A G, are mounted over the abutment point between two pipes and assume the holding function and the sealing function in the connection region of the pipes. For this purpose, at least one sealing element of a rubber-elastic material is provided, which is accommodated in a housing enclosing this or each sealing element. The housing including a sequence of elements following one another in the circumferential direction takes over the transfer of the forces acting on the pipes as a result of internal pressure or from the exterior.
WO2006/100628A1 discloses an anchoring element for a pipe coupling, the elements whereof are constituted by a first leg running essentially in the axial direction of the pipes and at least a second leg extending at an acute angle to the first leg. The spacing between the elements is preferably bridged by at least one deformable web. A seal for the transition between the pipes to be connected is held inside the anchoring element, at the outer side of which a further housing enclosing the anchoring element and the seal can be provided.
The friction-locked (or force-fitted) connection of the pipes is brought about by a force which is applied by at least one clamping belt surrounding the anchoring element in the circumferential direction. The ends of this clamping belt are braced with the aid of at least one essentially tangential clamping screw, that engages with bolts at the ends of the clamping belt, these bolts being disposed essentially in the axial direction of the pipes, and pulls the ends of the clamping belt towards one another.
As result of the spacing between the ends of the clamping belt, there is an interruption in the uniform force transfer in the region of the adjacent clamping belt. This interruption is possibly bridged inadequately by an additional component. As a result of the radial spacing of the application points of the clamping force of the clamping screw on the bolt of the clamping belt, with respect to the outer pipe circumference, flexural loading of the clamping screw and, thus, tensions in the clamping screw closure occur.
In the area of hose clips, GB229073A discloses an embodiment according to which one of the ends of the actual clamping strap is guided, in the coupled state, through an opening in the opposite end that is wider compared to the remaining length of the clamping strap. Both ends are constituted looped and receive bolts, between which a clamping screw is clamped. For the tensioning of the hose clip, the bolts and therefore the ends of the clamping strap are pushed apart by means of the damping screw. As also described in FR599968A, uniform pressing along the entire circumference of the hose or pipe can be achieved with such hose clips.
However, in order to be able to cover different diameters of hoses, the length of the clamping strap can be changed by a gradual change in the position of the looped ends. In order that the clamping screw can be used in any length of the clamping strap, individual discrete holes are provided in the clamping strap for the passage of the damping screw in GB229073A. At least one position of the clamping strap always lies, however, between the clamping screw and the seal and/or the hose or pipe, so that the clamping screw always lies to a considerable extent outside the outer pipe circumference and consequently considerable flexural loading of the clamping screw and tensions in the clamping screw closure also arise here due to this radial spacing of the points of application of the clamping force.
The problem of the present invention, therefore, is to propose a pipe coupling, wherein the aforementioned drawbacks are avoided. In particular, loading of the pipes that is as uniform as possible around the circumference should be ensured with the least possible loading of the clamping mechanisms and of their points of application.
Advantageous developments are presented in the figures and in the disclosure.
According to the present disclosure, provision is made such that the width of the two mutually overlapping ends of the damping belt together correspond at most to the width of the damping belt in the longitudinal portion, and at least one longitudinal slot extending in the longitudinal direction of the clamping belt is also provided in the end of the clamping belt that is passed through the longitudinal slot of the other end. The term “clamping belt” includes in particular clamping straps or all clamping elements that are essentially flat or strap-shaped between their ends.
Apart from carrying away the clamping forces in a direction tangential o the pipe cross-section and the uniform loading on the pipe over the entire circumference without interruption, the arrangement of the clamping mechanism, however constituted, very close to the outer pipe circumference is also possible. Tensions in the clamping mechanism, for example in an arrangement with bolts at the ends of the clamping belt, which bolts can be pushed apart by one or more clamping screws, are thus also avoided, as is flexural loading of the clamping screws themselves.
The width of each of the two ends preferably corresponds essentially to half the width of the clamping belt. The ends themselves can advantageously be constituted as closed loops.
The creation of the loops is very simple if, according to an advantageous embodiment of the clamping belt, the latter is constituted double-layered continuously over its entire length. For this purpose, it can preferably comprise a one-piece, closed strap with a fixed preselected length.
According to the present disclosure, the aforementioned problem is also solved by a pipe coupling of the type mentioned at the outset, the clamping belt of which is constituted according to one of the above features. Any kind of clamping mechanism, preferably a standard clamping mechanism with bolts at the ends of the clamping belt, the spacing of which is variable by at least one essentially tangential damping screw, may thus be disposed, in the radial sense, particularly close to the pipe circumference.
In particular, according to a further advantageous feature within the scope of the present disclosure, the at least one clamping screw may be passed through a longitudinal slot in each of the ends of the clamping belt. The clamping screw may thus be passed tangentially and particularly close to the pipe circumference, so that, even in the case of great clamping forces, only minimal flexural loading and also only very small tensions occur in any kind of clamping mechanism.
An advantageous version with a clamping mechanism making use of at least one clamping screw for the solution to the problem is characterised in that each clamping screw is screwed with its threaded portion into a threaded hole of one of the bolts and is accommodated with its threaded-side end in the other bolt in a recess, in particular a blind hole, the inner diameter of which becomes greater towards the exterior at least in the direction of the axis of the bolt. This feature ensures the reduction of stresses in the clamping screw closure and permits a geometrical compensation in the case of a change in the axes of the bolts at the ends of the damping belt in the plane containing the bolts and the damping screw, such as occurs for example when pipes of differing diameter are connected.
In order fully to enable the geometrical compensation and to further reduce or completely prevent tensions in the clamping screw closure, the recess, in particular the blind hole, has a larger diameter than the threaded-side end of the clamping screw in every radial direction of the clamping screw, and preferably widens outwards cone-shaped.
Provision is preferably made such that the clamping screw is provided with a spherically rounded screw end.
The advantages according to the present disclosure can also be obtained with a variant of the pipe coupling, wherein a bridge is provided for bridging the spacing between the ends of the clamping belt, said bridge being provided with a recess for the clamping screw. This bridge is preferably connected to one of the ends of the clamping belt. As a result of this feature, the clamping screw axis comes to lie as close as possible to the apex of the pipe during the bracing of the pipe coupling, wherein approximately half the shaft external diameter of the clamping screw is obtained as the smallest spacing. The force vectors of the clamping forces of the clamping belts thus come as closely as possible into agreement with the connecting line of the force vectors of the clamping forces, so that flexural loading of the clamping screw and tensions in its closure parts may be reduced or completely prevented.
According to the prior art, pipe couplings are known, in which at least one sealing element made of rubber-elastic material is disposed inside a housing. If need be, discs lying at the side of the sealing element and/or at least one anchoring element surrounding at least one sealing element can also be provided. As is disclosed for example in WO 2006/100628 A1, such an anchoring element can include a sequence of elements following one another in the circumferential direction, which elements in turn include a first leg running essentially in the axial direction of the pipes and at least a second leg extending at an acute angle to the first leg.
In order to obtain, here too, the aforementioned advantages of the tangential damping mechanism with damping forces running as dose as possible to the pipe circumference, a recess is provided in the anchoring element in each case in the regions of the damping screws, and at least a longitudinal portion of each clan ping screw comes to lie in each case at east partially, preferably essentially up to half its diameter, in a recess.
A preferred version within the scope of the present disclosure is characterised in that the recess is fashioned, preferably stamped, in at least one of the first legs of the anchoring element.
Provision is also preferably made such that a recess corresponding to the recess in the first leg of the anchoring element and/or in the bridge is fashioned in at least one sealing element, in the region whereof one of the clamping screws runs in each case.
At least two clamping screws may advantageously be provided, preferably symmetrical to the longitudinal central plane of the clamping belt.
The application of a force effectively identical over the entire circumference of the pipe or each pipe and uniformly loading the damping belt also over its entire length can be obtained by a further version of a pipe coupling according to the present disclosure, wherein both bolts are lengthened beyond the width of the clamping belt and at least one clamping screw is provided in each case in the lengthened ends of the bolts on each side of the clamping belt.
Further advantages, features and details of the invention emerge from the following description, in which examples of versions are described in reference to the drawings. The features may be essential to the invention individually in themselves, or in any combination.
The list of reference numbers is a component part of the disclosure. The figures are described in interrelated and comprehensive manner. Identical reference numbers signify identical components, reference numbers with different indices indicating functionally identical or similar components.
In the drawings:
At least one clamping belt 6 lies adjacent to the outer side of anchoring element 4 over essentially the entire circumference. If need be, clamping belt 6 could also lie directly on seal 3 or be provided at its inner side with a sealing layer. Ends 6a, 6b of clamping belt 6 are provided with bolts 7a, 7b orientated in the axial direction of pipe coupling 1 and therefore also of pipes 2 to be connected, between which bolts 7a, 7b at least one clamping screw 8 is clamped. Clamping screw 8 is rotated for the tensioning of clamping belt 6 in such a way that a force pointing away from the region of the overlapping of ends 6a, 6b of clamping belt 6 is produced, so that bolts 7a, 7b move away from one another. Bolts 7a, 7b are pushed into more remote positions from one another pointing away from the region of the overlapping of ends 6a, 6b of clamping belt 6. The clamping forces are thus carried away in a direction tangential to the pipe cross-section and, at the same time, a uniform force and loading over the entire circumference without interruption is produced on sealing element 3, if applicable, anchoring element 4, and finally also pipe 2, by clamping belt 6 lying essentially completely adjacent on sealing element 3 or anchoring element 4. Other clamping mechanisms are of course also conceivable, which manage without or with differently disposed clamping screws 8.
In order to facilitate the passage of bolt 7a at first end 6a running centrally out of clamping belt 6 through opposite end 6b of clamping belt 6, the length of this bolt 7a preferably corresponds to the smaller width of end 6a of clamping belt 6. End 6b runs away from the edges of clamping belt 6 and engages around opposite end 6a of damping belt 6, wherein the length of bolt 7b preferably corresponds to the entire width of clamping belt 6.
As can clearly be seen in
As emerges particularly clearly
Clamping screw 8 sitting in the longitudinal center of bolts 7a, 7b in
The cross-sectional view of
A further advantageous version of the clamping mechanism emerges from the cross-sectional representation of
Instead of a central clamping screw 8, it is also possible, as represented in
1 Pipe coupling
2 Pipe
3 Sealing element
3
a Sealing element recess
4 Anchoring element
4
a Element of anchoring element
4
b First leg
4
c Second leg
4
d Web
4
e Housing recess
4
f Third leg outwards
5 Plate
6 Clamping belt
6
a,
6
b Clamping belt ends
6
c Longitudinal slot in first clamping belt end
6
d Longitudinal slot in second clamping belt end
7
a,
7
b Bolts
7
c Threaded hole
7
d Blind hole
7
e Conical bottom of blind hole
8 Clamping screw
8
a Threaded portion
8
b Threaded-side end
9 Bridge
9
a Bridge end
9
b Bridge recess
Number | Date | Country | Kind |
---|---|---|---|
12164890.1 | Apr 2012 | EP | regional |
This application is a 35 U.S.C. 371 national-phase entry of PCT International application no. PCT/IB2012/05662 filed on Nov. 5, 2012 and also claims benefit of priority to prior European (EPO) application no. EP12164890 filed on Apr. 20, 2012, and parent PCI International application no. PCT/IB2012/056162 is expressly incorporated herein by reference, in its entirety and as to all its parts, for all intents and purposes, as if identically set forth in full herein.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/IB2012/056162 | 11/5/2012 | WO | 00 |