IL106969A - Insertion coupling for the connection of two polymer tubes - Google Patents

Abstract

Plug-in coupling (1) for the connection of plastic pipes (5), having in each case one clamping device in the end regions of the coupling socket (2) and having actuating devices for the clamping devices (3, 4). The plug-in ends of the plastic pipes (5) can be fixed by the clamping devices (3, 4). The clamping devices (3, 4) each exhibit a steel clamping ring (7) which is provided with a function slot (6) and exhibits, on the outer circumference, a clamping cone configuration (8) and, on the inner circumference, at least one clamping rib (9). In at least one of the two end regions of the coupling socket (2), the steel clamping ring (7) is inserted into a clamping-ring receiving means (12) which is open on the end-border side and interacts with a clamping counter-cone (11). The steel clamping ring (7) is set in the clamping-ring receiving means (10) with the aid of a screwed-on union nut (14). An inserted plug-in end (5) clamps against withdrawal by interaction, caused by retraction friction, of the clamping cone configuration (8) with the clamping counter-cone configuration (11).

Description

INSERTION - COUPLING FOR THE CONNECTION OF TWO POLYMER TUBES amoe a nn»»s m bv wn ηπηη >"y m>n The present invention concerns an insertion coupling for connecting together two pipes of plastics, particularly those that serve as conduits for soil embedded cables, employing a sleeve of plastics which is open at both its oppositely disposed ends, each of those ends comprising a clamping means, as well as means Tor actuating the said clamps, the pipe ends to be joined having smooth insertion end portions which are intended to be introduced into end regions of the said plastics, sleeve, the said pipe ends being fixable by the said clamping arrangements.

As generally known, at conventional insertion coupling of the said type, there are employed steel clamping rings of various shape, also - inter alia - such which are provided with a clamping cone formation acting reciprocally with a counter conicity. In all such cases there is provided a screw cap at both end portions of sleeve, serving as an actuating means for the clamping arrangement. The said screw cap is adapted to be screwed onto the respective end portion. Due to said positioning of the cap the clamping means become functionable . Some of the known clamping arrangements function in such a way that an inserted pipe end portion is safeguarded against becoming de-coupled by reciprocal, frictional inter-clamp action between a clamping cone formation and the associated counter cone. The known insertion couplings appear to be in need of improvement, both concerning fabricating operation, as well as regarding functional capacity, it being the object of the invention to provide such improvement.

Therefore the invention comprises in combination the following features: a) the clamping means comprise each a steel clamping ring which has a functional slit which ring has an external peripheral clamping conicity formation and internally at least one clamping ridge. b) in at least one end of the coupling sleeve the said steel clamping ring is located within a frontally open depression which co-acts with a clamping counter cone. c) the said steel clamping ring being located in the said frontally open depression is held fast by means of an annular screw threaded cap screwed onto the respective end portion of the coupling sleeve, an inserted pipe end being prevented from backward movement by reciprocal frictional rearward urge of clamp cone formation and counter cone.

Advantageously the said clamping ridge has a cross section design which is somewhat similar to a barbed hook. Thereby an inserted insert-end of pipe is securely held fast by the barbed hook formation. The functional slit in the above mentioned steel clamping ring could extend in parallelism with the longitudinal axis of the insertion coupling; but especially when there have been provided several such ridges in superposed to one another order at the internal periphery of a ring it would be preferable to provide an oblique slit at substantially 45° relative to the axis of the coupling.

In that case the whole internal circumferance of the clamping ridges or the major part thereof take hold of the introduced insert end. A preferred embodiment of the invention is characterised thereby that at least one frontal edge of the coupling sleeve includes circumferential internal rib defining an angle of substantially 45° relative to wall of the sleeve, such that a steel clamping ring allows its being most conveniently placed into an frontally open ring reception space.

According to a preferred embodiment of the invention which exeels by its simplicity as far as fabrication is concerned, the arrangement is such that the counter cone located at the open ring receiving space is actually formed at a clamping counter-cone-ring and is inserted with the steel clamping ring into the clamp ring receiving space. The screwed cap has advantageously an abutment shoulder for the clamping ring located in the clamping ring receiving space or for the counter cone ring respectively.

In case, that the screw cap, which is located at least at one end of the coupling is unscrewed the coupling connection of an inserted pipe end as well becomes releasable. The plastic pipe introduced at that side could then be pulled out. That would highly assist the introduction of cables into protecting conduit, but would also be of advantage with pipes which are not intended for use with cables. In those cases where there is a circumferential ridge of 45° at a frontal edge of sleeve this would make it possible to conveniently re-insert a pulled out plastics pipe end with an attached clamping ring or counter cone ring respectively.

Considering the way of function of the steel clamping ring, the clamping counter cone and the screw cap, there do exist several possiblities of practical embodiment within the frame-work of the invention. One embodiment exeels thereby that the steel clamping ring and the clamping counter cone are braced against each other by screwing on the screw cap. This feature - according to claim 7 - can be put into practice at both ends of the coupling. Another embodiment which within the scope of the invention is of particular importance is characterized thereby that steel clamping ring is positioned at axial and radial clearance, while the screw cap is screwed on and no insertion end being yet introduced, the ring then being increased in width by a subsequently introduced insertion end and is firmly clamped in the clamping counter cone due to a pull force of the steel clamp ring. This particular embodiment posseses the advantage that the insertion end can be introduced also at already screwed on screw cap and the latter need be screwed off only for relieving of a coupling connection of an inserted insert-end. Preferably this embodiment should be applied at both ends of the insertion coupling. In case that at this particular embodiment the clamping counter cone would have been realized at a clamp - counter-cone-ring which is to be positioned in a clamp-ring receiving space open edgewise, the said clamp ring receiving space is advantagely divided to form two superposed ( in lengthwise direction) compartments for the steel-clamping ring and the clamp-counter cone ring respectively.

The upper apartment for the counter cone ring is partitioned from the lower compartment by a circumferential step or shoulder, the clamping counter cone being positioned therein above the steel clamping ring, such that the steel clamping ring is at clearance relative to the longitudinal axis of the coupling. At this embodiment the steel clamping ring is preferably with a cylindrical portion formed below the outer circumferential cone formation. That feature permits keeping the wall thickness of the receiving space for the clamping ring at. not too reduced measurement.

It is also possible that the embodiment according to claim 7 is applied at one end of the coupling and the embodiment of claim 8 at its opposite end.

Another embodiment of the invention is characterised thereby that at one end range of the coupling sleeve the steel clamping ring is located in a receiving space which is distanced from the respective frontal edge, such space being formed at the internal wall of the coupling sleeve, a clamping counter cone, the steel clamping ring firmly clamping an inserted pipe end against rearward pull which might be caused by a reciprocal frictional effect of the clamping cone formation, with the clamping counter cone formation. The inventive coupling sleeve does permit in that embodiment the insertion of the end of a plastics pipe, such that the inserted end becomes already fixed at the instant of being introduced into the sleeve, this being the case without need for screwing on the screw cap.

Accordingly the operative arrangement for the clamping means operates automatically. This embodiment also has the additional advantage of needing only one screw cap for the opposite end of the insertion couplings.

It goes without saying that at an insertion coupling according to the invention packing and tightening means may be provided in a way that at appropriate locations tightening ring would be provided. In that connection a preferred embodiment of the invention is characterised thereby that at end ranges of the coupling sleeve, at the inward direction of insertion, behind the steel clamping rings and in front thereof respectively there is provided a receptive groove and an abutment surface for a lip packing which latter comprises a carrying ring of trapezoidal cross section and an integrally formed tightening lip the said carrying ring being placed in said receptive groove. It is recommended to provide an abutment for the introduced pipe ends at the median portion of the coupling such that depth of penetration of pipe ends which warrants proper function, would be ascertained.

The invention will now be described in detail using by way of example one embodiment thereof the features of which are depicted schematically by the accompanying drawing, which shown in Fig. 1 - an elevational view of embodiment of an insertion coupling comprising - shown in sectional view -of a s ew cap, also in section a steel clamping ring and a counter-cone-ring the latter (scew cap, clamping ring and counter-cone-ring) appearing detached.

Fig. 2, being of largely increased size relative to Fig. 1 is a longitudinal section of an insertion coupling according to the invention including in loco placed steel clamping ring, a counter-cone-ring and an inserted plastics pipe.

Fig. 3, is an enlarged view of cutting A of the article of Fig. 2.

Fig. 4, being an enlarged view of cutting B of the article of Fig. 2.

Fig. 5, similar to Fig. 2 is an enlarged view in longitudinal section of a somewhat different embodiment of the inventive coupling, including placed in loco the steel clamping ring and counter-cone clamp, without including an inserted pipe.

Fig. 6, is an enlarged view of cutting C of Fig. 5.

Fig. 7, finally, shows the steel clamping ring for the insertion coupling depicted perspectively .

The insertion coupling 1 shown in above Figures is destined to connect two ends of plastics pipes with each other.

Particularly, the connection might be one of in-soil deposited cable conducting pipes. Basis elements of such a coupling 1 comrise a sleeve 2 which is open at two oppositely disposed ends and for each end a coupling means 3 and 4 respectively. Further there are generally included operational means for the clamps which will be referred to below.

The plastics pipes which are to be joined together are inserted by their smooth ends 5 in the end portions of the sleeve 2 which is indicated in Fig. 2. The said ends 5 are fixed in the inserted position by clamping means 3 and 4 respectively. These means 3,4 comprise each a steel clamping ring 7 with functional slit 6. The said ring 7 has an external peripheral cone formation 8 and internally at least one clamping rib 9 (see Fig. 7).

In Figs. 1-4 there is shown one embodiment of the invention at which one side of the insertion coupling is contructed according to claim 7, while the opposite side of the coupling is constructed in accordance with claim 11. In that construction the steel ring 7 is placed in a first receving space 10 which is formed at the inside wall of the sleeve 2 and includes a clamping counter cone 11.

Another steel clamping ring 7 is located at an opposite end of sleeve 2 in a second receiving space 12 which is frontally open. This space 12 co-acts with clamping counter conicity 11 which is formed at a counter cone 13. The steel clamping ring 7 together with the counter cone ring 13 is insertable into the edgewise open receiving space 12. The arrangement is such that the steel clamping ring 7 introduced into the first receiving space 10 does securely hold an inserted pipe end 5 against pull back which might be the result of reciprocal frictional bias between the clamping conicity 8 with the counter cone formation 11. Moreover the arrangement is designed in a way that the clamping ring 7 located in the second frontally open receiving space 12 is held fast in the space 12 by a ring shaped screw cap screwed on the respective end portion of the coupling sleeve 2, such that in the said position an inserted end portion 5 is safeguarded against pull back due to reciprocal frictional effect between the clamp conicity 8 with the counter cone formation 11. The screw cap 14 is provided in the embodiment with an abutment 15 counter cone ring 13 located in the receiving space 12. The steel clamping ring 7 and the counter cone ring 13 are braced against each other by screwing on the screw cap 14. The bracing effect may be dispensed with if the formations 13a are employed as indicated in Fig. 3.

Fig. 5 and 6 illustrate an embodiment of the invention whereat both ends of the insertion coupling are designed in accordance with claim 8.

This embodiment is characterised by the following features: At both ends of the coupling sleeve 2 a steel clamping ring is located in a receiving space 12 which latter co-acts with a clamping counter cone 11 formed at a clamping counter cone ring 13. The steel clamping ring .7 and the counter cone ring 13 are held fast by means of a screw cap 14 screwed on the end portion of the sleeve 2. The screw cap 14 according to the sample of the embodiment now described includes an abutment 15 for the clamping counter cone 13. An introduced insert end 5 is adapted to be held at counter cone 13 against pull back possibly due to reciprocal friction effect of clamping cone formation 8 with the clamping counter cone 11. This embodiment is distinguished thereby that the steel clamping ring 7, at the screw cap 14 in screwed on position, without introduced insert end 5, is positioned with some axial and radial play within receiving space 12 and is thus subject to certain expansion and following insertion of insert end 5 with exertion of pull force the steel ring 7 is firmly clamped on the counter cone 11. Due to this pull force the steel clamping 7 is pulled into the clamping counter cone 13 which latter applies itself onto the abutment 15 of the screw cap 14, the clamping cone formation 8 of steel ring 7 thereby being firmly clamped in the counter cone 11 onto the clamping counter cone 13. The receiving space 12 is divided in the embodiment into two sections 22, 23 which relative to the lengthwise extension of the coupling 1 are positioned above one another, destine to enclose the steel ring 7 and the clamping counter 13 respectively. The upper space 22 housing the clamping counter cone 13 is partitioned off lower space 23 by a step 24, the counter cone clamping ring 13 being supported thereon above the steel ring 7, such that steel ring 7 is subject to a play in the longitudinal axis of the coupling 1.

In the example of the embodiment the steel ring 7 is provided below the exterior, circumferential cone formation 8 with a cylindrical portion 25. Such a steel clamping ring is. also seen in Fig. 7. This feature makes it . possible to avoid exessive reduction of wall thickness of sleeve 2 in a section 26 of receiving space 12.

From Figs. 3, 4 and 6 it can be gathered that the clamping ribs 9 have bar 8 shaped cross section. Fig. 7 shows that steel ring 7 includes a preferably oblique functional slit 6 ascribing an angle of substantially 45 relative to the longitudinal axis of the coupling 1. This slit warrants, as already stated above, an especially firm hold of steel ring 7 at insertion ends 5. In Fig. 5 it can be seen that in that embodiment both frontal edges of coupling sleeve 2 are circumferentially skived off at 27 at about 45 In Figs 3 and 5 it can be seen the end portions of sleeve 2 in entry direction of pipe ends 5 include receiving grooves 16 and lay-on surfaces 17 for a lip packing 18. The latter comprises a carrying ring 19 of trapezoidal cross section and an integrally therewith moulded lip 20. Ring 19 is located in groove 16. In the median rang of the coupling 1 a shoulder formation 21 can be seen for insertion ends 5. The lip packing 18 allows the employ of the inventive coupling also in connection with pipe lines conducting fluids under pressure or sub-pressure. Obviously, inserted pipe ends may also be turned about their axes.

Claims (13)

CLAIMS:

1. Insertion coupling (1) means for connection, of two plastic pipes, particularly soil deposited cable conduits including a coupling sleeve (2) open at two oppositely disposed frontal end edges, each end of which being provided with clamping means (3) (4) at the ends of the said sleeve (2) and further including actuating means for said clamping means the plastic pipes to be connected being provided with smooth insertion ends (5), destined to enter the said plastics sleeve, the insertion ends (5) being fixable by the said clamping means (3,4 respectively), the foregoing combination of elements being characterised by following features a) the clamping means .(3,4) comprise each a steel clamping ring (7) which includes a functional slit 6 and has at its external periphery a clamping cone (8) formation and internally at least one clamping ridge (9) b) at least at one of the end ranges of the coupling sleeve (2) the said steel clamping ring (7) is located in an open end clamping ring reception space (12) which latter space co-acts with a counter cone (11) c) the steel clamping ring (7) inserted into the clamping ring reception space (10) is fixedly held in the respective end of the sleeve (2) by means of a ring shaped screw cap (14) screwed onto the sleeve (2) an inserted end being safeguarded against rearward dislocation bias by reciprocal frictional action between cone and counter cone - 11a - d) the end portion of the coupling sleeve (2) in the direction of pipe end insertion (5) there are provided reception grooves (16) and application surfaces (17) for a lip packing (18) comprising a carrying ring (19) of trapezoidal cross section and an integrally formed sealing lip (20), the said carrying ring (19) being located in the said reception groove (16), an inserted insertion end (5) being safeguarded against rearward pull bias firmly clamp the counter cone formation (11) and tightened by the lip formation (18). 12

2. The insertion coupling according to claim 1 wherein the clamping ridge is of barbed hook like cross section.

3. Insertion coupling according to claim 1 or 2 wherein the steel clamping ring has an oblique slit defining an angle of about 45 with the lengthwise axis of the coupling.

4. The insertion coupling according to all or any one of claims 1 to 3 wherein at one frontal edge of the coupling sleeve is skijed off externally peripherally to form an angle of substantially 45° at the sleeve wall.

5. The insertion coupling according to all or any one of claims 1 to 4 wherein clamping counter cone located in the frontally open clamping ring reception space is formed at clamping counter cone (13) and is introduced with the steel clamping ring (7) into frontally open clamping ring reception space (12).

6. The insertion coupling according to all or any one of claims 1-5 wherein the screw cap has an abutment for edgewise open steel clamping ring located in the clamping ring reception space or the clamping counter cone ring, respectively.

7. The insertion coupling according to all or any one of claims 1-6, wherein the steel clamping ring are pressed against one another by screwing on the screw cap. 106969/2

8. 0. The insertion coupling according to any one of claims 1-7 wherein the steel clamping ring in the position of screwed on screw cap and without inserted pipe end is positioned at axial and radial clearance relative to the clamping ring reception space, such that an inserted pipe end does widen the steel clamping ring and due to contact of the pipe end under pull force the steel clamping ring is firmly clamped in the counter cone.

9. The insertion coupling according to claim 8 wherein the steel clamping ring is provided below the external circumferential clamping cone formation (8) with a cylindrically shaped portion.

10. The insertion coupling according to claims 8 or 9 wherein the embodiment according to claim 8 is applied at both ends of the invention coupling.

11. The insertion coupling according to any one of claims 1-9 wherein at one end portion of the coupling sleeve the steel clamping ring is located in a rec... space distanced from respective frontal edge, the said space being shaped at the interior wall of the sleeve and steel clamping ring of an insectial pipe end being safeguarded against retraction by reciprial frictional action between clamping cone formation (8) with the clamping counter cone formation (11).

12. The insertion coupling according to any one of claims 1-11 wherein at the median range of the coupling sleeve there is provided an abutment for an inserted pipe end .

13. Insertion couplings, substantially as hereinbefore described and depicted by accompanying drawings.