IL40452A - Pipe coupling - Google Patents

Description

η 'ϊ τ 3 πη Pipe coupling IORDECHAI DRORI 0/ 38303 This invention relates to a pipe coupling and is partic-ularly concerned with a coupling capable of coupling a pipe formed of a plastics material to a fitting or of coupling together a pair of such pipes. Such pipes are, for example, used for irrigation purposes and it is a requirement that they should be capable of being, readily coupled and uncoupled and, when coupled the coupling should be secure and seal tight.

It is an object of the present invention to provide a new form of pipe coupling capable of fulfilling wholly or partially the above referred requirements.

According to the present invention, there is provided a pipe coupling producing a tight seal and a firm clamping action when applied to a pipe, comprising: A. a collar formed with an internal screw- threaded portion adjacent to an opan end thereof, and with an internal annular shoulder between said screw-threaded portion and the opposite end of the collar; B. a sleeve having a leading portion receivable within the collar and formed with external screw-theads cooperable with the internal screw-threads of the collar, said sleeve also having a manipu]£:able trailing portion to be disposed external to the collar to enable screwing the leading portion of the sleeve into the collar, at least the leading portion of the sleeve being axiaLly split to permit the radial contraction thereof and being formed on its inner surface with inwardly directed protrusions; C. and a resilient sealing ring of a diameter to be loosely received around the pipe and to be disposed between said internal shoulder of the collar and the end face of the leading portion of the sleeve when the latter is threaded into the collar; the screw-threads of the collar and sleeve being formed in cylindrical surfaces of substantially uniform diameter throughout the length of their - - respective screw-threaded portions and having a sloping back face facing the trailing portion of the sleeve and m said open end of the collar, respectively, such that when the pipe is disposed within the collar and the sleeve, with the screw-threads of the leading portion of the sleeve inter-engaging those of the collar and the manipulatable trailing portion of the sleeve projecting from the collar, and with the sealing ring interposed between the internal shoulder of the collar and said end face of the sleeve, rotating the sleeve by means of its manipulatable trailing portion to displace the sleeve axially of the collar; (i) first effects the seal by causing the said end face of the sleeve to apply an axial force to the sealing ring to axially compress it and thereby to radially expand it into sealing engagement with the pipe and collar; (ii) and then, by virtue of the sealing ring and shoulder thereafter serving as an abutment limiting the further axial displacement of the sleeve within the collar, causes the sloping faces of their interengaging screw-thcais to effect the radial contraction of the threaded portion of the sleeve for the complete length of the interengaging threads to force the sleeve protrusions into the pipe throughout the length of the said interengaging threads.

The pipe coupling described further includes an annular pressure ring interposed between the sealing ring and the end face of the sleeve to transfer the axial force from the latter to the sealing ring along the complete annular surface of the sealing ring. Also, the sleeve is preferably completely split through both its leading end trailing portions.

In accordance with a still further embodiment of this invention the collar is formed integrally with an inner tubular skirt spaced from the threaded inner wall of the collar and defining with the threaded inner wall an annular cylindrical space afapted to receive the sleeve and an end of the pipe. ^ For a better understanding of the present invention and to show how the same can be carried out in practice reference will now be made to the accompanying drawings in which: Fig. 1 is a longitudinally sectioned view of a first form of pipe coupling in accordance with the present invention; Fig. 2 is a cross-sectional viex? of the pipe coupling shown in Fig. 1 taken along line XX II; and Fig. 3 is a cross-sectional view of a second form of pipe coupling in accordance with the present invention.

As seen in Figs. 1 and 2 of the drawings the pipe coupling comprises a collar member 1 having a first axial portion la which is internally threaded over the major portion of its length and a second axial portion lb of lesser diameter than the portion la and separated therefrom by a shoulder lc. The free end of the axial portion lb is externally screw threaded so as to permit the screw coupling of the collar member 1 to a fitting as required. Formed in the inner wall of the axial portion lb is an abutment shoulder Id which serves as a stop for an inserted pipe 2 to be coupled by the coupling.

A sleeve member 3 formed preferably as a one-piece unit of a plastics material, is externally screw-threaded and is formed on its inner surface with inwardly directed circumferential saw-tooth serrations 4, these external screw-threads constituting the leading portion of the sleeve. The sleeve 3 is provided with a trailing portion constituted by an outwardly directed end flange 5 which is knurled so as to facilitate turning of the sleeve. As can be seen particularly in Fig. 1, - - the screw-threads in the sleeve and collar members are buttress threads formed in cylindrical surfaces of uniform diameter throughout the length of the respective screw-threaded portions, the back face of each screw-thread turn sloping towards the trailing portion of the sleeve and the open end (right end) of the collar respectively.

As can be seen in Fig. 2 of the drawings the sleeve 3 is axially split through both its leading and trailing por-tins , there being thereby formed an axial gap 6.

A resilient sealing 0-ring 7 and an annular pressure ring 8 are successively located within the collar portion la the 0-ring 7 abutting the shoulder lc.

In use the pipe 2 is inserted into the collar 1 until the pipe end abuts the shoulder Id and the sealing and pressure rings 7, 8 are located in the annular space between the exterior of the pipe and the interior surface of axial portion la of collar member 1. Rings 7, 8 are thus located in the annular space between shoulder lc and the inner end face of sleeve member 3. The inner diameters of the sealing and pressure rings are such that the pipe can easily be inserted therethrough.

The sleeve 3 which surrounds the pipe 2 is now screwed into the collar 1 and the axial displacement of the sleeve 3 into the collar 1 continues until the leading end of the sleeve abuts the pressure ring 8 which, in its turn bears on the sealing ring 7, Once this has occurred continued screw rotation of the sleeve 3 within the collar 1 causes the axial compression of the sealing ring 7, and thereby its radial expansion into sealing engagement with pipe and collar, so as to form an effective tight seal around the pipe 2. When the further axial displacement of the sleeve 3 into the collar! is substantially prevented by its abutting the pressure and compresse^ sealing rings 8 and 7, the external screw threading of the sleeve 3 is displaced with respect to the internal screw threading of the collar 1 with the consequential contraction of the sleeve 3. In other words, the sealing ring and shoulder serve as an abutment limiting the further axial displacement of the sleeve within the collar, causing the sloping faces of the interengaging screw-threads of the sleeve and collar to effect, by a camming action, the radial contraction of the threaded portion of the sleeve for the complete length of the interengaging threads to clamp the sleeve firmly onto the pipe throughout the length of the interengaging threads. As a result the serrations 4 bite into the pipe 2. When the sleeve 3 will have been turned by a maximum amount, for example until the gap 6 therein will have been closed, the serrations 4 will have bitten into the pipe 2 resulting in the firm gripping of the pipe 2 and at the same time, the end of the sleeve 3 presses against the pressure ring 8 and compresses the 0-ring 7, causing an effective sealing of the coupling.

As shown in Fig. 1, fluid carried by the pipe may enter the annular space containing rings 7, 8 and exert an axial thrust thereon i a direction tending to expell the sleeve member from the collar member. Such thrust is resisted by the screw-thread connection between these members causing seal 7 to compress against ring 8 and to radially expand increasing the effectiveness of the seal. Additionally, the inclined threads of the sleeve and collar members are thrust against each other causing the sleeve member to be radially compressed thereby further increasing the grip of the coupling on the pipe.

Furthermore whilst in this specific embodiment the sleeve 3 is split along its entire length, a partially split sleeve ac ohoxm in Fig.—· can equally well be employed. As in this case where the serrations 4 consist of peripheral sawtooth-like protrusions it can be arranged that the partially split ring has at least one set of peripheral protrusions intact in which case the intact set of serrations serve to effect a seal as well as to grip and the provision of other sealing means such as ah 0-ring, can if desired be dispensed with.

Reference will now be made to Fig. 3 of the drawings in which is illustrated a modified form of coupling devices in accordance with the invention. In this embodiment the sleeve 3 is essentially identical with the sleeve 3 shown in Fig. 1 whilst the collar 1 is in priciple similar to the collar 1 shown in Fig. 1 but, is in addition, provided with an itegrally formed, inwardly located, tubular skirt 11 which extends parallel to the portions la and lb of the collar 1 and is spaced therefrom by an annular spacing 12 which, in the region opposite the wall portion lb is relatively narrow so as to be capable of receiving the end of the pipe 2 to be coupled and in the region opposite the wall portion la is relatively wide so as to be capable of reoiving both the pipe 2, the sleeve 3 and the sealing and pressure rings 7-8. As can be seen from the drawing, the tubular skirt 11 is inserted into the pipe 2 to be coupled and therefore constitutes a rigid bearing surface against which the pipe bears thereby ensuring the more effective gripping of the pipe 2 by the saw tooth serrations 4 of the sleeve 3.

Whilst in the embodiments described with reference to Figs. 1 to 3 of the drawings, the pipe coupling has ■ been shown as serving to couple at one end a pipe 2 and to be adapted for screw connection at an opposite end to an appropriate fitting (not shown) , it will be realised that the inventive concept inherent in the coupling described can be readily applied for use in coupling together two pipes of the same or differing diameter. Ths it can readily be envisaged that the externally threaded free end of the coupling collar 1 csi be replaced or formed integrally with a further collar portion la similar to that shown and an additional split sleeve 3 and, if required, sealing rings be provided.

In all, the embodiments hitherto described the sleeves 3 have all been at least partially split and the gripping action has been effected as a consequence of the contraction of the split sleeve 3 which contraction arises out of the relative displacement of the interengaging screw threads of the sleeve and collar.. This relative displacement takes place when axial displacement of the sleeve 3 with respect to the collar 1 is prevented as a result of abutment. Such relative displacement of the screw theads can c most advantageously be achieved with screw threading of the buttress type as illustrated in the drawings. However other types of screw threads can equally well be employed for this purpose the only screw thread which cannot be used being screw thEads of substantially rectangular cross-section.

Whilst in all the embodiments described above the sleeve has been described as constituting an integral unit, such as unitary sleeve can be replaced for example by two component, coaxial sleeves an outer one being provided with the screw thread designed to engage in the internal screw threading of the collar whilst the inner sleeve being provided with the protrusions adapted to grip the pipe, means being provided for coupling the component sleeves together. Such means can for example be constituted by conical surfaces or interengaging ribs and grooves or the like.

Claims (7)

P.A. 40452/3 WHAT IS CLAIMED IS:

1. A pipe coupling producing a tight seal and a firm clamping action when applied to a pipe, comprising: A. a collar formed with an internal screw-threaded portion adjacent to an open end thereof, and with an internal annular shoulder between said screw-threaded portion and the opposite end of the collar; B. a sleeve having a leading portion receivable within the collar aid formed with external screw-threads cooperable with the internal screw-threads of the collar, said sleeve also having a manipulatable trailing portion to be disposed external to the collar to enable screwing the leading portion of the sleeve into the collar, at least the leading portion of the sleeve being axially split to permit the radial contraction thereof and being formed on its inner surface with inwardly directed protrusions ; C. and a resilient sealing ring of a diameter to be ΰ loosely received around the pipe and to be disposed between said internal shoulder of the collar and the end face of the leading portion of the sleeve when the latter is threaded into the collar; the screw-threads of the collar and sleeve being formed in cylindrical surfaces of substantially uniform diameter throughout the length of their respective screw-threaded portions and having a sloping back face facing the trailing portion of the sleeve and said open end of the collar, respectively, such that when the pipe is disposed within the collar and the sleeve, with the screw-threads of the leading portion of the sleeve interengaging those of the collar and the manipulatable trailing portion of the sleeve projecting P.A. 40452/3 from the collar, and with the sealing ring interposed between the internal shoulder of the collar and said end face of the sleeve, rotating the sleeve by means of its manipulatable trailing portion to displace the sleeve axially of the collar; (i) first effects the seal by causing the said end face of the sleeve to apply an axial force to the sealing ring to axially compress it and thereby to radially expand it into sealing engagement with the pipe and collar; (ii) and then, by virtue of the sealing ring and shoulder thereafter serving as an abutment limiting the further axial displacement of the sleeve within the collar, causes the sloping faces of their interengaging screw-threads to effect the radial contraction of the threaded portion of the sleeve for the complete length of the interengaging threads to force the sleeve protrusions into the pipe throughout the length of the said interengaging threads.

2. The pipe coupling as defined in Claim 1, further including an annular pressure ring received between the sealing ring and said end face of the sleeve to bridge the split in the sleeve and to transfer the axial force from the latter to the sealing ring uniformly about the complete annular surface of the sealing ring.

3. The pipe coupling as defined in Claim 1, wherein the sleeve is axially split through both its leading and trailing portions, and is formed of a one-piece plastics unit.

4. The pipe coupling as defined in Claim 1, wherein the collar is formed with a second internal annular shoulder of smaller internal diameter than the first-mentioned shoulder between it and said opposite end of the collar for engaging the end of the pipe when inserted therein. P.A. 40452/3

5. . The pipe clamp as defined in Claim 1, wherein the manipulatable element on the trailing portion of the sleeve is a manually grippable flange.

6. The pipe coupling as defined in Claim 1, wherein the collar is formed with an inner, axially-extending skirt underlying Said annular shoulder and spaced therefrom for receiving the end of the pipe.

7. A pipe coupling producing a tight seal and a firm clamping action when applied to a pipe, comprising: A. a collar formed with an internal screw-threaded portion adjacent to an open end thereof, and with an internal annular shoulder between said screw-threaded portion and the opposite end of the collar; B. a sleeve having a leading portion receivable within the collar and formed with external screw-threads cooperable with the internal screw-threads of the collar, said sleeve also having a manipulatable flange to be disposed external to the collar to enable screwing the leading portion of the sleeve into the collar, at least the leading portion of the sleeve being axially split to permit the radial contraction thereof and being formed on its inner surface with inwardly directed protrusions ; C. a resilient sealing ring of a diameter to be loosely received around the pipe and to be disposed between said internal shoulder of the collar and the end face of the leading portion of the sleeve when the latter is threaded into the collar; and D. an annular pressure ring receivable between the sealing ring and said end face of the leading portion of the sleeve so as to bridge the split therein; P.A. 40452/3 the screw threads of the collar aid sleeve being formed in cylindrical surfaces of substantially uniform diameter thro out the length of their respective screw-threaded portions and having a sloping back face facing the trailing portion of the sleeve and said open end of the collar, respectively, such that when the pipe is disposed within the collar and the sleeve, with the screw-threads of the leading portion of the sleeve interengaging those of the collar and the manipulatable flange of the sleeve projecting from the collar, and with the sealing ring facing the internal shoulder of the collar and the pressure ring facing said end face of the sleeve, rotating the sleeve by means of its manipulatable flange to displace the sleeve axially of the collar ; (i) first effects the seal by causing the said end face of the sleeve to apply an axial force via the pressure ring to the sealing ring to axially compress it and thereby to radially expand it into sealing engagement with the pipe and collar; (ii) and then, by virtue of the sealing ring, pressure ring, and shoulder thereafter serving as an abutment limiting the further axial displacement of the sleeve within the collar, causes the sloping faces of their interengaging screw-threads to effect the radial contraction of the threaded portion of the sleeve for the complete length of the interengaging threads to clamp the sleeve firmly onto the pipe throughout the length of the said interengaging threads . - 12 - For the A plicants NERS