The present invention relates to methods and devices fo joining pipes and for attaching pipes to connecting pieces o T-pipes, bends and equipment such as valves, faucets, mea suring instruments, etc.

It is previously known to slide pipes or tubes onto the out side of connecting pieces and to clamp them securely to th connecting piece by means of a clamping device. It is als known to employ a fitting sleeve that covers both pipes o tubing ends, or the pipe/tubing end and a connecting piece Further, it is known to use gaskets in connection with suc seals.

According to the prior art, pipes are usually joined by mean of welding, soldering, compression joints, clamping sleev couplings or flanges. The various methods have their stron and weak aspects and have therefore won favor in differen areas. In the art of sanitary equipment, for pipes of plia ble material such as plastic, it is particularly the methods employing clamping rings and clamping sleeves that have gained ground, as well as welding for weldable plastic.

For pipes of annealed copper, the common practice involves soldering to bends, T-pipes and sockets, this being presently the only permissible method for installations that are to be concealed in walls or flooring.

A common coupling method for open installations which is both rapid and simple involves compression joints in combination with support linings. he disadvantage of this method is that the pipes are easily damaged as a result of the assembly method, which results in leakage after a period of use. For

this reason it is not permitted to use this method where th pipes are to be built into walls or floors.

Welding methods have been developed for plastic piping, bu in practice this is a time-consuming process compared to us of compression joints and, moreover, may only be used o weldable plastic, while other types of plastics are steadil gaining an increasing share of the market.

A number of different types of compression joints are als available for plastic, some of them for use in combinatio with support linings, while others are intended to be use without them. One of such types without support linings i damaging to the surface of the pipe under the clamping ring and therefore cannot be used on pipes having a diffusio block at the surface. Couplings for pipes carrying hot wate require support linings.

It is a common feature of all types of compression joint that the compression of the clamping ring should take plac through axial movement of the adjacent parts, and for thi reason the effective width of the clamping ring must b limited. The combination of axial movement for the ring' adjacent parts, achieved by virtue of standard threads an the narrow clamping ring, affords poor control with th surface pressure between the ring and the pipe, which easil results in damage to the pipe.

The numerous parts in a compression joint give it a consider able weight and make it expensive to produce.

The present methods and devices are aimed at alleviating th problems that have just been described.

The characterizing features of the invention are disclosed i

the following speci ication, the subsequent patent claim and the enclosed figures.

One achieves through the invention a controlled clamping the pliable pipe against the connecting piece or support lining, or, alternatively, for hard pipes (without a suppo lining), of the sleeve lining against the pipe. The sai clamping is controlled by visually observing when the slot i the inner sleeve closes, and also by determining through marked increase in the adjustment moment or force that th slot has been closed, which is a sign that the desired compr ession has been achieved. Tightening in excess of what i necessary to obtain desired compression force, however, wil not damage the pipe, since the force is absorbed by the inne sleeve which is dimensioned for this purpose and whic together with the support lining and the pipe, now causes th outer sleeve to expand.

For pliable pipe, it is convenient, to use an internal suppor in the form of a straight sleeve, a bend, a T-pipe or connecting piece on a valve, etc., which is inserted into th pipe up to a marked stop. On the outside of the pipe i placed a clamping sleeve having an outer whole sleeve that i and an inner sleeve having a through-going slot.

For hard copper piping, steel pipes and the like where support lining is not needed, the inner sleeve is permitte to cover both pipe ends, or the pipe end and connecting piec of, e.g. a valve block, while sealing is achieved through th use of a gasket.

In order for the present invention to function in practice, it is of considerable importance that the slot in the inner sleeve be correctly dimensioned relative to the pipe's toler ance and the desired compression force. Further, the mater ial thickness in the inner sleeve and outer sleeve must b

balanced in relation to each other to minimize undesirab deformation of the pipe on exaggerated tightening thereof.

The combination of a support lining in the case of a join connecting piece at a bend, T-pipe, valves, etc., and clamping sleeve having dimensions in accordance with t above, provides a solution for joining pipes or coupli piping to equipment which can be carried out without uninte tional damage to the pipes. On hard pipes the same effect achieved by use of a clamp coupling in combination with gasket.

The invention will now be described In more detail wi reference to the enclosed figures.

Fig. la shows a pipe, and fig. lb a bend with connecti pieces.

Fig..2 shows an inner sleeve of a clamp coupling, and fig. shows an outer sleeve of the clamp coupling.

Fig. 3 shows a pipe coupled to a bend by means of the cla coupling in fig. 2.

Fig. 4 illustrates a pipe that has been coupled to a conne ting piece on a bend.

Fig. 5 illustrates the coupling of fig. 4 in tightened stat

In fig. la the pipe Is designated with reference numeral The bend 2 in fig. lb has connecting pieces 3, 3'. The inn sleeve of the clamp coupling is designated in fig. 2a wi reference numeral 4, and the inner sleeve is provided with slot 5 as well as a wrench grip 6. The outer sleeve designated by reference -numeral 7 and has a wrench grip 8.

As is shown in fig. 3, the pipe 1 is brought over the conne ting piece 3 of bend 2, and on the outside of this assembly the inner sleeve 4 with the slot 5 and the wrench grip a stop edge 6 is assembled together with the outer sleeve having the mentioned wrench grip 8. The outer sleeve 7 screwed toward the combined wrench grip and stop edge 6 a is tightened. When this happens, the slot 5 will be co pletely clamped together, as clearly indicated in fig. 3.

In fig. 4 there is shown a pipe 9. The reference numeral designates, for example, a pipe or a connecting piece on bend, a T-pipe or the like. To hold the pipe 9 and the pi or connecting piece 10 in coupled position there is used clamp coupling consisting of an inner sleeve 11 having a sl 12 and a wrench grip 13 together with an outer sleeve 14 wi wrench grip 15. In fig. 4 all the parts are stiown assembl and ready for tightening. Between said pipe 9 and the pi or connecting piece 10 there is provided a gasket 16 in cut-out 17 on the inner sleeve 11. At each interior end the inner sleeve a bead 18 is thus formed. Although n shown on fig. 4, there is also a corresponding bead 18 at th other end of the inner sleeve, preferably in connection wit the threaded .section thereof.

In fig. 5 the clamp coupling is shown in tightened state whereby the slot 12 is closed and the bead 18 is presse against and somewhat into the pipe or connecting piece 1 such that a slight indentation 20 is formed around the pip or connecting piece 10. In a similar manner by means of th other bead (not shown), a constriction against the pipe will take place. This will ensure that there is no axia movement between the parts 9 and 10 when the clamp couplin is tightened.

The joining of pliable pipes or coupling of such pipes to connecting piece is accomplished by sliding the sleeve part of the clamp coupling in assembled state onto the pipe 1

hereafter the connecting piece 3 is pushed into the pipe 1 Then the clamp coupling 4-8 is slid into position such th the threaded section covers the connecting piece 3 on extension piece, bend, T-pipe, a valve, etc. In this positi the sleeve portion 7 (outer sleeve) Is rotated while it abu contact with the combined wrench grip and stopper means The rotation is done by turning the wrench grips 6 and 8 i opposite directions until the slot 5 Is clamped into I closed state. The pipe 1, which is pliable, will thereby cold-shrunk securely to the connecting piece 3, the surfa of which has an approximately saw-toothed form.

When the slot 5 is closed, the mechanical constriction of t pipe end 1 over the corrugated, preferably saw-tooth form connecting piece 3 is completed, and a tight and mechanical durable connection is achieved between the T-pipe, the ben the valve, etc., designated in general with the referen numeral 2, against the pipe 1.

When the slot 5 in the sleeve part 4 is closed, a continu tightening will now cause this sleeve part 4 to be compress together with the pipe end 1 and the connecting piece which requires a considerable increase In tightening mome and therefore clearly indicates that the tightening phase h been completed.

On continued tightening in this phase, the sleeve part will expand, provided the wall thickness of the sleeve correctly dimensioned, and unintentional deformation of t pipe end 1 is therefore avoided.

Pliable pipes are often delivered in coiled form, which m result in a cross-sectional profile that deviates from t circular. In order for the support sleeve or connecti piece on a T-pipe, bend or equipment to fill the pipe 1 maximum degree, it is recommendable to make such suppo sleeves or sleeves conical at their end in order to expa

the smallest diameter of the pipe by means of the conic configuration. The rounded tips on the conical sections wi on tightening cause the deformation of the pipe to occ without indications of rupture, which is an important pr condition for avoiding breakage when the pipe is subjected mechanical stresses.

It is important that the threaded sections of the clam coupling lie over the connecting piece section 3. Thi means, in the embodiment form shown in fig. 3, that* th wrench grip parts 6, 8 on, respectively, the inner lining an the outer sleeve face away from the bend 2. During tighten ing of the compression joint the slot 5 will, as has bee mentioned, be closed, and the tightening moment will finall increase considerably, which both visually and purely mechan ically indicates that the operation is completed. In th tightening phase the wrench grip part 6 on the inner sleev 4 will not be subjected to the same compression force as th rest of the sleeve, since the wrench grip part 6 lies outsid the outer sleeve 7. This together with the fact that th wrench grip part 6 is more heavy duty than the rest of th sleeve and meets the same internal resistance from the pipe means that this part of the slot does not close completely o tightening. It is definite that the slot 5 will be close completely under the outer sleeve 7, while at the outer edge furthest from the outer sleeve 7, It will have a slight bu distinct opening. The result is that the pipe 2 will receiv maximum intended deformation under the outer sleeve 7, deformation which decreases gradually and approaches zer under the wrench grip part 6.

A pipe in engagement as outlined above will endure a consi derably greater exterior mechanical stress before It is over loaded than is the case with use of conventional compressio joints where there is no distribution of the stresses at th edges.

Although the above describes the coupling of pipes, it wil immediately be understood that this may also apply to tube for example, those made ^* of plastic.

The joining of pipes or coupling of a pipe to a connecti piece on a T-pipe, bend, valve housing or the like as depi ted in fig. 4 and 5 shows mechanical contraction and limit tion of the pipe's deformation, similar to that shown in t preceding figures.

For hard copper piping, steel pipes and the like there is need for a support lining inside the pipes. One may atta the clamp coupling directly to the outside of the pipe 9 the slot 12 in the inner sleeve is closed, and this task solved by insertion of the cylindrical gasket 16 situated a recess 17 on the inside of the inner sleeve 11.

At the starting point, as shown In fig. 4, the gasket 16 h a thickness corresponding to the depth of the groove 17. Wh the slot 12 in the inner sleeve 11 is closed, the bead 18 a the other bead, not shown, at the other end of the thread section on the inner sleeve 11 will thereby be pressed in respective pipe wall parts 9, 10, and the gasket will simu taneously be put under pressure, thereby providing for sea ing between the pipe end 9 and the pipe or the connecti piece 10. As is apparent from fig. 5, the bead 18 will cau indentations to be made in the pipe or the connecting pie 20, and corresponding indentations will also be made in t pipe 9 by the bead that is not shown. The parts are there mechanically locked to each other.

It has been shown through repeated trials that when one us an inner sleeve without a slot, plastic deformation of t inner sleeve occurs when it is tightened with the for required for effective axial locking. The deformation wi make It difficult later on for the sleeve to be moved axial on the pipe when the outer sleeve is loosened.

If the inner sleeve has a through-going slot, as in th present embodiment, and a width adapted to the pipe's toler ances and the constriction thereof on tightening, it wil resume its original form when the outer sleeve is loosened This is due to the slot and the natural resilience that wil be present in the material of the inner sleeve; and when th outer sleeve is thus loosened, the sleeve parts in the clam coupling could be slid in onto the free pipe end or ends, an a faucet, a bend, T-piece, for example, between two pipe end or the like could thus be removed without the pipe end o ends being forced to move axially or radially. In a perman ent installation where the parts are to be replaced, this i of considerable importance in simplifying maintenance an repair. This, too, has been shown through experiments.