AU2009307148B2

AU2009307148B2 - A pipe coupling

Info

Publication number: AU2009307148B2
Application number: AU2009307148A
Authority: AU
Inventors: Marshita Binti Abdul Malik
Original assignee: KINDRACO HARDWARE Sdn Bhd
Current assignee: KINDRACO HARDWARE Sdn Bhd
Priority date: 2008-10-22
Filing date: 2009-07-31
Publication date: 2016-02-04
Anticipated expiration: 2029-07-31
Also published as: CN102203490B; CN102203490A; WO2010047573A1; NZ592253A; AU2009307148A1

Abstract

A pipe coupling is disclosed comprising a body (20) providing a tubular conduit enabling fluid flow therethrough from one end to the other. Each end is provided with an inner tubular portion into which a pipe end (10, 12) may be inserted. The body (20) has external threading and an outer tubular portion having a diameter larger than the inner tubular portion wherein an annular surface transiting between said inner and outer tubular portions is provided. A gasket ring (40) having a diameter suitable to fit around the pipe end (10, 12) is provided seated at the annular surface. A clinching sleeve (60) is further provided comprising a ring portion at one end having a diameter disposable within the outer tubular portion of the body (20) and providing an abutment surface against the gasket ring (40) upon being seated. A plurality of clinching flaps extends from the other end of the ring portion wherein each of the clinching flaps' inner surface is provided with gripping means and distributed to encircle a pipe end (10, 12). A coupling nut (80) is also provided having an inner opening at one end provided with internal threading complementary to said body's external threading, and an outer opening at the other end sufficient for the pipe end to be inserted therethrough.

Description

WO 2010/047573 PCT/MY2009/000110 A pipe coupling TECHNICAL FIELD 5 This invention concerns a coupling assembly for a pipe end-to-end joint which generally comprises of a tubular body for conducting fluid between one pipe end to the other end, a clinching sleeve, gasket ring and coupling nut for fluid proofing at each end of the body. Improved features on fluid-proofing and pre 10 assembling of the coupling are disclosed. BACKGROUND ART 15 In the art of end-to-end jointing of polymeric pipe lines for the conduct of fluids, various methods components have been used. Central to the various components is a body (which may also be referred to as "tubular body" hereinafter) provided with longitudinally opposing end openings for enabling fluid communication between the respective ends through the body. Other 20 components such as gasket ring, a clinching sleeve and/or coupling nut are provided essentially for fluid-proofing the joints. In a typical early jointing method, Malaysian Patent No. MY-127,837-A (Hansen), (corresponding to U.S. Patent No. 5,687,994), a tubular body is provided with 25 ends that are adapted to be inserted into the pipe ends. Barbs (6) and/or annular ribs (10, 14) are provided for grip and fluid-proofing respectively while a coupling nut (2) is provided to fasten the pipe end onto the body's end that has been inserted into the polymeric pipe end for engaging its inner surface. 30 It may be seen from this inventorship, as disclosed in his later U.S. Patent No. 5,857,719 (Hansen), that the insertion of joining parts into the pipe end is WO 2010/047573 PCT/MY2009/000110 -2 being abandoned in favour of inserting the pipe end into the joining parts of the tubular body for the polymeric pipe's outer surface engagement. A further development is the introduction of a sleeve as an intermediary component between the body end and the coupling nut to provide a better interface 5 between the body and coupling nut. Elastic or compressible gasket ring is also introduced as a fluid-proof seal between the interfacing surfaces. PCT Published Patent Application No. WO 95/035508 (Philmac) might have been a precursor to this sleeve and gasket ring development. 10 The sleeve has been variously called as "compression sleeve", "clinching sleeve", "gripping sleeve" and the like and which we refer to hereinafter as "clinching sleeve" for ease of reference in this specification. Further developments made to the sleeve leads to the development of a ring portion for abutting the gasket ring and a clinching portion for gripping on the outer 15 surface of the polymeric pipe end. Such development may be seen in PCT Published Patent Application No. WO 02/504669 (Philmac) wherein the gasket ring abutting portion and the gripping portion are provided as two separate components. 20 Another aspect of development lies in the clinching sleeve's gripping features such as that disclosed in PCT Published Patent Application No. WO 03/010461 (Philmac) wherein metal band with spikes are provided on the inner surface of the clinching sleeve as yet another separate component. There thus appears to be a gradual proliferation of parts and components of a pipe coupling assembly 25 to order to achieve better jointing. SUMMARY OF DISCLOSURE 30 We would like to disclose a pipe coupling which may be completely assembled with 3 components, namely the body, clinching sleeve and coupling nut, apart WO 2010/047573 PCT/MY2009/000110 -3 from the gasket ring, which is able to provide effective jointing such as that for end-to-end jointing of polymeric pipes. Many improvements may be made or provided on the existing components without the need for introducing additional components or parts, as we shall show in the following. 5 To this end, we have now disclosed a pipe coupling comprising a body having a tubular conduit for enabling fluid flow therethrough from a first opening to at least a second opening wherein at least one of said openings is provided with an inner tubular portion into which a pipe end may be inserted; an outer 10 tubular portion having a diameter larger than the inner tubular portion wherein an annular surface transiting between said inner and outer tubular portions is provided; and external threading; a gasket ring having a diameter suitable to fit around said pipe end and be seated at said annular surface; a clinching sleeve comprising a ring portion at one end having a diameter 15 disposable within the outer tubular portion of the body and providing an abutment surface against said gasket ring upon being seated; and a plurality of clinching flaps extending from the other end wherein each of said clinching flaps' inner surface is provided with gripping means and distributed to encircle a pipe end; and a coupling nut having an inner opening at one end provided 20 with internal threading complementary to said body's external threading, and an outer opening at the other end sufficient for the pipe end to be inserted therethrough. In a first aspect of our pipe coupling, at least a protrusion is provided on the 25 inner surface of the outer tubular portion of the body and at least a protuberance is provided on the outer surface of the clinching sleeve ring portion whereby in mutual cooperation, said clinching sleeve's turning within said body to less than a turn. Preferably, a plurality of protrusions and/or a plurality of protuberances is provided. Preferably still, 3 protrusions are 30 provided mutually equidistant along said inner surface of said body. Three protuberances are preferably provided mutually equidistant along said outer WO 2010/047573 PCT/MY2009/000110 -4 surface of said clinching sleeve ring portion. The 3 protrusions may preferably be further provided mutually equidistant along said outer surface of said clinching sleeve ring portion, thereby mutually cooperate to limit the clinching sleeve to one-third turning. 5 In one specific embodiment, at least a protrusion is provided on the inner surface of the outer tubular portion of the body and at least a keyway is provided on the outer surface of the clinching sleeve ring portion whereby the protrusion is insertable into said keyway and limiting the clinching sleeve's 10 turning within said body to within keyway width. Preferably, a plurality of keyways is provided corresponding to a plurality of protrusion. Six keyways are preferably provided mutually equidistant along said outer surface of the clinching sleeve ring portion and three protrusions are provided on the body in complementary positions to be inserted into corresponding keyways. 15 Preferably, the protrusions are provided sufficiently narrow to allow limited sliding within a keyway such that turning of clinching sleeve within in the body is limited accordingly. In a second aspect of our pipe coupling, the gripping means provided on the 20 inner surface of the clinching flaps comprises barb edges which tips define a circumference in which a pipe end may be inserted thereinto without said barb edges cutting into said pipe end surface. The clinching flaps are preferably flexed inwardly due to pressure imparted by the coupling nut's inner surfaces upon tightening of said coupling nut such that the barb edges securely grip upon 25 the pipe end surface. Moreover, the clinching sleeve may be symmetrically provided with three clinching flaps which inner surfaces having barbs with blunt edges. Preferably, each of the clinching flap corners are rounded and are separated from each other by a U-shape cut out. Another preferred feature is having a central portion of the clinching flap base adjoining the ring portion of 30 the clinching sleeve to be provided with an indentation.

WO 2010/047573 PCT/MY2009/000110 -5 In a third aspect of our invention, the clinching sleeve ring portion's abutment surface has its circumferential edges rounded. Preferably, the abutment surface comprises a raised, rounded circumferential lip which may comprise a circumferential concave surface contoured to cover about an inner [lower] 5 segment of the gasket ring's surface. Most preferably, the circumferential concave surface is contoured to cover about an inner or lower quadrant of the gasket ring's cross-sectional surface. Alternatively, the clinching sleeve ring portion's inner opening comprises a tapering. 10 In a fourth aspect of our pipe coupling, the coupling nut's external surface are provided with longitudinal ribs extending from the inner opening end over at least a neck portion at the outer opening. Preferably, the outer opening end edge is provided with inwardly extending peripheral flange thereby retaining clinching flap ends within said outer opening end as the coupling nut is 15 rotated to tighten, and wherein the remaining diameter of the outer opening is sufficient for a pipe end to be inserted therethrough. The peripheral flange is preferably continuous around the outer opening end edge, forming a lip around said outer opening. 20 In a fifth aspect, at least a bump is provided in the root or between adjacent crests of the threading of the body external threading. At least a depression complementary to the bump is preferably provided along a crest of the coupling nut's internal threading. As a preferred embodiment, a plurality of depressions is provided along the coupling nut's internal threading. 25 Preferably, the bumps are provided at about the penultimate tightening part of the threading. Another set of bumps may be similarly provided on the threading on the opposite side of the body's circumference. Preferably, the bumps are provided to engage just before the ending of complementary threading of the coupling nut or body. The engagement may cause 30 deformation of the complementary threading upon tightening.

WO 2010/047573 PCT/MY2009/000110 -6 In a sixth aspect of our pipe coupling the body's inner tubular portion is provided with a plurality of ribs longitudinally extending substantially along and symmetrically distributed around said inner tubular portion. The plurality of ribs is preferably profiled to provide even tight fit around a pipe 5 end insertable thereinto. Each of the aforesaid components, i.e. clinching sleeve, tubular body and coupling nut may be used independently as components in conventional compatible pipe coupling assemblies. Similarly, many of the features of the 10 respective components may be provided independently and the respective component used in conventional compatible pipe coupling assemblies. Our aforesaid components may also be provided as a preassembled coupling. 15 LIST OF ACCOMPANYING DRAWINGS The aforementioned embodiments of our invention and their respective functional principles and advantages may be better understood with reference to the following accompanying drawings, which together the detailed 20 description thereafter, serves to illustrate exemplary but not limiting implementations of our invention, in which: FIGURE 1 shows an assembled pipe coupling installed on a pipe end joint according to our invention in elevation view; 25 FIGURE 2 illustrates the pipe coupling of FIG. 1 in cross-sectional view; FIGURE 3 depicts a pre-assembled pipe coupling of our invention independent of the pipe joint in elevation view; 30 FIGURE 4 exemplifies the pre-assembled pipe coupling of FIG. 3 in cross- WO 2010/047573 PCT/MY2009/000110 sectional view; FIGURE 5 represents a tubular body according to our invention in elevation view; 5 FIGURE 6 illustrates the tubular body of FIG. 5 in cross-sectional view; FIGURE 7 shows a number of tubular body embodiments in which the features of our invention may be employed; 10 FIGURE 8 depicts 2 embodiments of the clinching sleeve according to our invention in perspective views; FIGURE 9A exemplifies one of the clinching sleeve of FIG. 7 in side elevation 15 view, while FIGURE 9B and FIGURE 9C shows an alternative embodiment of the clinching sleeve's limited turning with keyway feature; FIGURE 10A, FIGURE 10B, FIGURE 10C, FIGURE 10D, FIGURE 10E and FIGURE 1OF which represent detailed cross-sectional view of the clinching 20 sleeve; FIGURE 11 shows a coupling nut according to our invention in side elevation view; 25 FIGURE 12 comprising FIGURE 12A illustrates the coupling nut of FIG. 11 in cross-sectional view, with FIGURE 12B and FIGURE 12C showing schematic views of various features of the coupling nut; FIGURE 13 depicts the pipe coupling according to our invention comprising 30 the aforementioned tubular body, clinching sleeve and coupling nut being preassembled with a gasket ring inserted; and WO 2010/047573 PCT/MY2009/000110 -8 FIGURE 14 exemplifies the pipe coupling of FIG. 13 wherein the coupling nut is tightened with the clinching sleeve in full grip upon the pipe. 5 DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS As a general embodiment of our invention, with collective reference to FIGURE 1, which shows an external elevation view, and FIGURE 2, which 10 shows a cross-sectional view, of our proposed pipe coupling assembly is comprised of a tubular body (20), a gasket ring (40) (hidden in FIG. 1), clinching sleeve (60), and a coupling nut (80) forming an end-to-end joint between two pipe ends (10, 12). FIGURE 3 and FIGURE 4 show the same pipe coupling assembly without the pipe ends inserted thereinto. 15 Shown in external elevation view in FIGURE 5, and in cross-sectional view in FIGURE 6, is the body (20) which comprises a tubular conduit (22) which enables fluid to flow therethrough from a first opening (24) to at least a second opening (26), and vice versa. As with conventional embodiments of pipe 20 coupling, the body may be provided as various types of joints such as that shown in FIGURES 7A - 7J with FIGURE 7A showing a male threaded straight joint or adaptor; FIGURE 7B showing a reducing straight joint or adaptor; FIGURE 7C showing a female threaded straight joint or adaptor; 25 FIGURE 7D showing a reducing T-joint; FIGURE 7E showing a male T-joint; FIGURE 7F showing a female T joint; FIGURE 7G showing an equal T-joint; FIGURE 7H showing an equal elbow or L-joint; 30 FIGURE 71 showing a female elbow; and FIGURE 7J showing a male elbow.

WO 2010/047573 PCT/MY2009/000110 -9 Our invention may even be practised on an outlet or inlet tubes of a container wherein only one side of the tube or "body" is threaded for coupling with a clinching sleeve (60), a gasket ring (40) and a coupling nut (80). As such our 5 invention has been defined in such a way to include such "one-sided" or "one end" implementation of our pipe coupling assembly. In a normal pipe coupling assembly, however, a tubular body (20) would typically have at least a pair of each of the clinching sleeves (60), gasket rings (40) and coupling nuts (80). 10 The opening is provided with an inner tubular portion (28) into which a pipe end (10) may be inserted. This inner tubular portion (28) extends to an outer tubular portion (30) having a diameter larger than the inner tubular portion (28). The transition between the inner (28) and outer (30) tubular portions may be provided as an annular surface (32) for seating a gasket ring (40). The is gasket ring (40) typically has a diameter to provide a snug fit around a pipe end and the annular surface (32) diameter and profile may thus be provided accordingly. The external surface of the outer tubular portion (30) may be provided with 20 external threading (34) complementary with the inner threading of a coupling nut (80). As shown in the drawings, the threading (34) may extend over to the external surface of inner tubular portion (28) if necessary so as to enable the coupling nut (to be explained later) to provide the desired fastening. The middle portion may be provided with specific patterns of ribs (36) or spokes to 25 enable the body to be gripped by a spanner or a custom wrench, or simply by hand. As a supplementary or optional feature the body may be provided with a plurality of ribs (27) longitudinally extending along and symmetrically 30 distributed around said inner tubular portion such that a pipe end may be inserted snugly into the inner tubular portion (28) of the body (20) and in an WO 2010/047573 PCT/MY2009/000110 -- 10 axially centralized manner so that any torsional stress exerted on the pipe line outside of the coupling would not result in any leverage stress against a particular section or point of the gasket ring which might stress affect the effectiveness of the fluid-proofing properties of the gasket ring. The number of 5 ribs may range from 3 to 8, for example, and distributed equally around the inner tubular portion (28) surface. The plurality of ribs (27) may also be profiled accordingly to provide a tight or snug fit around the pipe end (10) inserted into the inner tubular portion (28). 10 A key component of our pipe coupling assembly is the clinching sleeve (60) which is shown in isolation in FIGURE 8, FIGURES 9A - 9C and FIGURE 10 collectively. Generally, the clinching sleeve (60) may be said to comprise of two parts, i.e. a ring portion (62) at one end and at the other end a plurality of clinching flaps (64) extending therefrom. The ring portion (62) has a diameter 15 that makes the ring portion (62) disposable within the outer tubular portion (30) of the body (20). The ring portion (62)'s end is also provided with an abutment surface (66) for engaging or interfacing against the gasket ring (40) upon being seated on the annular surface (32) of the body (20). Each of the clinching flaps (64) extending from the other end of the clinching sleeve (60) is 20 provided with gripping means (68) at the flaps' inner surface. The clinching flaps (64) are preferably distributed to encircle the pipe end (10). With reference to FIGURE 11 and FIGURE 12, yet another component of our pipe coupling assembly is the coupling nut (80) which is provided with internal 25 threading (82) along an inner opening (84) at one end. The internal threading (82) is provided complementary to the tubular body's (20) external threading (34). At the other end, the coupling nut (80) is provided with an outer opening (86) having an diameter that is sufficient to admit a pipe end (10) to be inserted therethrough. 30 Having described the basic configuration of the components of our pipe WO 2010/047573 PCT/MY2009/000110 -11 coupling assembly, we shall now describe in detail the various functionalities of the coupling and the features of the components enabling such functionalities in the following. 5 One of the advantage of our pipe coupling assembly lies in the feature which limits the turning of the clinching sleeve (60) within the body's (20) outer tubular portion (30) when the coupling nut (80) is turned and tightened during coupling operation. In a conventional coupling assembly, the turning of the clinching sleeve causes the ring portion's edge or abutment surface to turn 10 against the gasket ring, while compressing it as it is disposed seated in the tubular body's annular surface. This has been a major source of frictional wearing of the gasket ring, in fact, a major cause of damage of the gasket ring at the very first installation of the coupling assembly, leading to fluid leakages shortly thereafter. 15 To reduce such damage, we have endeavoured to limit the circumferential distance over which the clinching sleeve's ring portion (62) may turn within the tubular body's outer tubular portion (30). This in turn limits the abutment surface's (66) friction against the gasket ring (40) and thus reduces the 20 damage caused to the gasket ring (40). There are many possible ways of reducing the turning, as well as reducing the degree of turning, of the clinching sleeve (60). One such method is the keyway locking in which mutually abutting key is provided on each of the tubular engagement surfaces. In the most basic configuration, a protrusion (38) is provided on the inner 25 surface of the outer tubular portion (30) of the body (20) and a protuberance (78) is provided on the outer surface of the clinching sleeve ring portion (62) such that the protrusion (38) and the protuberance (78) mutually cooperates to abut each other at some point in the turning so that the clinching sleeve's (60) turning is limited to less than a turn. 30 Of course, it might even be more desirable to further limit the turning by WO 2010/047573 PCT/MY2009/000110 -12 providing more protrusions (38) and/or more protuberances (78). For example, by having 3 protrusions (38) distributed equidistantly around the inner surface of the outer tubular portion of the body, against a single protuberance (78) on the clinching sleeve's outer surface of the ring portion (62), one may limit the 5 turning to less than one-third, although no doubt one may also achieve this by having 3 protuberances (78) against the 3 protrusions (38). On the other hand, having limited surface sliding between the gasket ring's elastic surface against the abutment surface (66) of the clinching sleeve's ring 10 portion (62) might nevertheless be deemed desirable to establish proper and snug seating for the gasket ring and for compressive surface contact to achieve better fluid-proofing purposes. Hence, having more protrusions than 4 or reducing the turning to less than a quarter may not lead to better advantage in terms of fluid-proofing. 15 Another embodiment of the clinching sleeve limiting turning within the body (20) is shown in FIG. 9B and FIG. 9C. wherein keyways (77) are provided on the clinching sleeve (60)'s ring portion (62) so that it may be inserted into the body with the protrusions (38) complementarily slotted into the keyways (77). 20 Once within a keyway (77), the protrusion (38), if designed to be sufficiently narrow, may be slidable within the width of the keyway (77), thus allowing for limited turning of the clinching sleeve (60) within the body as it is tightened. Turning should not be dispense with altogether because a limited turning allowed will assist in the O-ring interfacing with contacting surfaces of the 25 body (20) and clinching sleeve for better fluid-proof sealing. Preferably, a plurality of keyways (77) is provided corresponding to a plurality of protrusion (38). For ease of insertion of the clinching sleeve into the body (20), the plurality of keyways should complementarily match the positions of 30 the protrusions (38) on the body (20). For example, if six keyways (77) are provided to match the 3-flap embodiment of the clinching sleeve shown in FIG.

WO 2010/047573 PCT/MY2009/000110 -13 9B and FIG. 9C, they should be provided mutually equidistant along the outer surface of said clinching sleeve ring portion (62) so that the 3 protrusions (38) on the body (20) are complementarily positioned to be inserted into corresponding keyways (77). 5 Among the advantages gained with this embodiment of the clinching sleeve with keyway is limiting turning according to the number and width of the keyway provided. For example, in the above described embodiment where 6 keyways (77) are provided, the turning of the clinching sleeve (60) in the body 10 (20) is 1/6 turn or 600 which is optimal for tightening and yet allow for sliding compression of the O-ring to achieve the desired sealing action on the contacting surfaces without exerting too much wear on the elastic polymeric material of the 0-ring. 15 Another major advantage arising from this keyway configuration is that the clinching sleeve's diameter to suit the internal diameter of the body since the protuberance's (78) and the gap necessary for the protuberance's (78) interfacing are now abolished or considerably reduced. A clinching sleeve (60) having larger diameter is relatively more robust and improve its interfacing 20 with the inside surface of the body (20). With the gap between the clinching sleeve (60) and the body (20) reduced or abolished, the support for interfacing surfaces of the O-ring is thus increased and fluid-proof sealing increased. [0011 As described above, at the other end of the clinching sleeve, a plurality of clinching flaps (64) extending from the ring portion (62) wherein 25 each of the clinching flaps (64) is provided with gripping means (68) at the flaps' inner surface. The gripping means (68) are preferably provided as barb edges which tips define a circumference in which a pipe end may be inserted thereinto without much resistance arising from cutting or scrapping of the pipe end surface as the pipe end (10) is pushed through the encircling 30 clinching flaps (64) and through the ring portion (62).

WO 2010/047573 PCT/MY2009/000110 -14 While there are many possible configurations of the clinching flaps (64) being distributed around the sleeve, an ideal configuration would be to have the flaps distributed to evenly encircle the pipe end (10) so that the gripping force on the pipe end (10) surface may be evenly applied. To this end, it is proposed 5 that any number from 3 flaps to 6 flaps may be practically configured on the clinching sleeve (60). In FIGURE 8, a 3-flap and a 4-flap embodiment of the clinching sleeve are shown. The barb edges of the gripping means (68) may either be sharp edges capable 10 of cutting, nicking or lacerating into the pipe end surface to provide a strong grip, or with blunt or rounded edges of a profile that is just sufficient to provide a firm grip on the pipe end without defacing the surface. The variation or range between sharp cutting edges and rounded edges profile of the barbs will depend on the material of the pipe to be coupled, fluid pressure 15 to be contained, degree of leakages tolerable, the pipe joint's integrity required (e.g. whether the pipe is subjected to stress test of pulling out of the coupling) and whether quick decoupling and recoupling is required (e.g. where nicking or lacerating of the pipe end would be undesirable since it might be rendered unsuitable for recoupling due to the defaced pipe end) and so forth. 20 Another desirable feature of the clinching sleeve (60) is to provide each of the clinching flap (64) end as having its corners and edges rounded (65). Similarly, the cutting or space between flaps is also preferably rounded (67) or provided as a U-shape cut as well. Such rounding of edges and corners will 25 reduce the incidences of these points nicking or scrapping onto adjoining or abutting components be it the pipe end (10), gasket ring (40) or tubular body (20) which may result in unnecessary obstruction or rough insertion of parts, causing damage to abutting component, etc. In the case of the rounded corners of the U-shape cut (67) between clinching flaps (64), such feature may reduce 30 material cracking as the flaps (64) are flexed during stress arising from pipe end (10) insertion and/or tightening of the clinching sleeve around the pipe end WO 2010/047573 PCT/MY2009/000110 -15 when the coupling nut (80) is tightened. In another embodiment or preferred variation of our clinching sleeve (60), the extent of the U-shape cut (67) may also be varied between the 3 or 4 cuts 5 (depending on the number of clinching flaps (64) to be provided) such that the remaining width of the ring portion (62) corresponds with extent of the cut. The advantage of varying each or at least one of the U-shape cut into ring portion (62) is providing a varied flexure response of the clinching flaps (64) during the insertion of the pipe end (10). FIGURE 1OF shows an example of such a clinching 10 sleeve (60) provided with varying extent of the U-shape cuts (67). Yet another feature of the clinching sleeve (60) provided for ease of flexure of the clinching flaps (64) is the thinning of the base of the clinching flap (64) at the ring portion (62) such as that shown in FIG. 8 and FIG. 9A as square 15 indentation (70). Such thinning or reduction of material will ease the clinching flap (64) to bend or flex when stressed either from inside (e.g. when a pipe end (10) is inserted, causing the flap to flex outwardly) or from outside (e.g. when the coupling nut (80) is tightened to push the clinching flap to flex inwardly). In the latter, the degree of inward flexure of the clinching flaps (64) 20 due to pressure imparted by the tightening of the coupling nut (80) may be critical to impart the necessary force to enable the barb edges (68) to securely grip upon the pipe end (10) surface. With respect to the abutment surface (66) on the ring portion (62) end of the 25 clinching sleeve (60), further detailed features will now be described in respect of abutting the gasket ring in the most preferred manner. To enable the abutment surface (66) to come into contact with the gasket ring as gently and smooth as possible, the circumferential edges of the abutment 30 surface (66) should preferably be rounded (72) as shown in FIGURE 10A. With such rounded edges, incidence of lacerating or damaging the gasket ring WO 2010/047573 PCT/MY2009/000110 -16 surface via abrasive action when the clinching sleeve (60) is turned and/or pushed inwardly into the tubular body (20) may be reduced. As a further improvement, the abutment surface (66) may be provided as a 5 raised, rounded circumferential lip (73) as shown in FIGURE 10B. This raised and rounded circumferential lip (73) may be more effective in abutting the gasket ring and keeping the edges (72), which may have been rounded though, from directly contacting the gasket ring. Yet a further improvement to this abutment surface (66) may be made by provided the raised, rounded io circumferential lip with a concave surface (74) as shown in FIGURE 10C. The raised, rounded and concave surface, by having concave profile conforms to the gasket ring's surface, will ensure a complementarily opposing seating surface on the side of the clinching sleeve for the gasket ring to be securely seated in the annular surface (32) of tubular body (20). 15 The most preferred embodiment of the abutment surface (66) of the clinching sleeve is providing the circumferential concave surface (75) to be contoured to cover an inner or lower segment of the gasket ring's (40) segment (42) as illustrated in FIGURE 10D. It is to be understood that the word "lower" is a 20 relative term in that should the gasket ring is laid on a horizontal plane and the clinching sleeve is inserted into a vertically-oriented tubular body (20) and approaches the gasket ring from the bottom. Another perspective of this embodiment may be described as providing the circumferential concave surface (75) as contoured to cover about an inner, lower quadrant of the gasket 25 ring's (40) surface in cross-sectional view. While such outwardly-oriented concave surface (75) may be seen as effective in seating the gasket ring by providing an outwardly or expansive translation of force from the clinching sleeve so that the gasket ring (20) is compressed 30 outwardly against the annular surface (32) in the body (20), a geometric inversion or mirror image of such concave surface (75) may also be possible.

WO 2010/047573 PCT/MY2009/000110 -17 This is to say that the clinching sleeve's ring portion edge may be provided with an inwardly-oriented concave surface (76), as shown in FIGURE 10E, so that the gasket ring (20) is compressed inwardly or constrictively around the pipe end surface when the clinching sleeve is tightened and pushed into the 5 body (20). It may be said that if a balance between the outwardly compressive force and inwardly constrictive force on the gasket ring is desired then the embodiment shown in FIG. 10C, wherein a symmetrically concave surface (74) is provided, may be chosen. 10 Thus, it should be noted that the abutment surface (66) of the clinching sleeve (60) is capable of many variation in contour and profile to provide an effective abutment and compressive surface against the elastic nature of the polymeric gasket ring seated in the tubular ring (20)'s annular surface (32). Another point to be issued is in respect of the phrase "to be seated" used in referring to 15 the gasket ring. This phrase is used to indicate upon being placed in a position (or poised) to abut rather than actually being seated, so that the actual placement of the gasket ring is not limited to being actually placed in its seat in the tubular body (20)'s annular surface (32), such as during pre-assembly of the various components of our pipe coupling. 20 As shown in some the drawings of the various configuration and orientation of the concave surfaces, the inner circumferential opening of the clinching sleeve (60) may be tapered slightly (79) outwardly to ease the gasket ring's abutting the 3 different contacting surfaces at the juncture, i.e. against the tubular 25 body's annular surface (32), clinching sleeve's abutment surface (66) and with the pipe end (12) surface. It may be noted that the provision of this tapering (79) may either be outwardly or inwardly and is optional in case any one of the following circumstances arises or advantages to be taken. 30 The tapering (79) may be provided for flexural compensation when the clinching flaps (64) are pushed inwardly, such that the pipe-contacting surface WO 2010/047573 PCT/MY2009/000110 -18 of the ring portion (62) inner surface remains flat on the pipe end (10) surface. For ease of insertion and withdrawal of pipe end (10) where partial withdrawal may need to be made during assembling and affixing of the pipe coupling, or when decoupling or adjusting before the coupling is tightened and locked, this 5 tapering (79) would also be advantageous. Another situation where the tapering is useful is in providing grip on the pipe end (10) surface by the ring portion (62) of the clinching sleeve (60) which otherwise would only have gripping means provided at its outer end, i.e. the clinching flaps (64) 10 The final essential component of our pipe coupling to be described is the coupling nut (80) which is collectively depicted in FIGURE 11 in external view, and FIGURE 12A in cross-sectional view. One preferred feature of the coupling nut is having ribs (84) that run longitudinally along the nut's external surface from the inner opening (84) to cover at least part of the neck 15 portion (83). These longitudinal ribs (84) provide reinforcement to the coupling nut structure as well as grip to the user hand or tool in turning and fastening the nut along its internal threading (82) to cooperate with the tubular body's (20) external threading (34). 20 Another feature of our coupling nut (80) lies in the outer opening (86) wherein its edge is provided with an inwardly extending peripheral flange (87). The extent of this flange (87) would be sufficient to retain the clinching flaps' (64) ends therewithin as the nut is tightened to constrict the flaps inwardly around the pipe end while at the same time the remaining diameter of the outer 25 opening (86) is still sufficient to admit a pipe end having the designated diameter for the particular pipe coupling assembly. While the peripheral flange (87) may be provided as discontinuous extensions (87a) in various configurations, as shown in FIGURE 12B, a continuous flange around the edge of outer opening (86) forming a lip therearound is preferred. 30 Further supplementary features of the coupling nut (80) in cooperation with WO 2010/047573 PCT/MY2009/000110 -19the tubular body (20) may now be described. One or more bumps (29) may be provided in the root (or in between crests) of the body's (20) external threading. Complementarily, one or more depression (89) may also be provided along the crest of the coupling nut's internal threading such that in the tightened 5 threading between the two mutually cooperating threading, the bump (29) may be snugly seated in the depression (89) and thus avoid loosening of the threading. This bump-in-depression engagement is similar to the tongue-in groove engagement in that the features may also be provided vice versa between the cooperating parts, e.g. the bump (29) may be provided on the 10 inner threading of the coupling nut (80) and the depression on body's external threading. With this optional configuration in mind, our following description is thus made as a non-limiting to the first example. Shown schematically in FIGURE 12C, as the coupling nut's threading is 15 gradually raised (90) for the tightening, the provision of the depression (89) may cause a click sound as the bump (29) winds over the tightening and drops snugly into the depression (89). A plurality of depressions (89) may be provided along the tightening threading so that the corresponding click sounds made by the bump engaging each depression in series may indicate the various 20 positions of engagement. For example, the first click may indicate the position of the pipe coupling being preassembled and ready for insertion of the pipe end while subsequent clicks indicate the tightening of the coupling nut (80) over the clinching sleeve (60). 25 As a preferred embodiment, the depressions are not provided on the threading but the tightening portion of the threading is instead provided as thinned crests such that the tightening of the nut coupling would cause the bump to deform the thinned crests at the tightened end of travel of the bump on the crest and thus create a corresponding depression. 30 FIGURE 13 and FIGURE 14 respectively show by way of comparison the pre- WO 2010/047573 PCT/MY2009/000110 -20 tightening assembly of the pipe coupling and the tightened assembly wherein the barbs are shown to have clinched upon the pipe end surface. As our present invention of a pipe coupling is comprised of 3 main components, 5 namely tubular body (20), clinching sleeve (60) and coupling nut (80), many of the features described herein may be provided only on one of the components and used with conventional components. Similarly, features that require cooperation of two or more components may also be effective employed in conventional couplings by provided the feature only on one of the components. 10 Accordingly, we have endeavoured to provide for claims directed to individual components such as the clinching sleeve, body and coupling nut without forsaking the unity of our invention and which are to be considered as falling within our general inventive concept. This inclusive coverage statement also covers our preassembled coupling in which one or more features may not be is operational or effective until a pipe end has been inserted and tightened therein. While the foregoing description covers in detail specific and exemplary features of each of the components of our pipe coupling assembly, it would be 20 obvious to a skilled person that many of the aforesaid features may be reconfigured, substituted, modified or provided as alternative configurations but still using the same general concept, functionality or working principle. These variations, substitutes and alternative embodiments which are not specifically mentioned herein are not to be considered as departures from our 25 invention but shall be considered as falling within the scope and letter of the following claims.

Claims

1. A pipe coupling comprising: - a body (20) having a tubular conduit for enabling fluid flow therethrough 5 from a first opening (24) to at least a second opening (26) wherein at least one of said openings is provided with - an inner tubular portion (28) into which a pipe end (10, 12) may be inserted; - an outer tubular portion (30) having a diameter larger than the inner 10 tubular portion (28) wherein an annular surface (32) transiting between said inner (28) and outer (30) tubular portions is provided; and - external threading (34); - a gasket ring (40) having a diameter suitable to - fit around said pipe end (10, 12) and 15 - be seated at said annular surface (32); - a clinching sleeve (60) comprising - a ring portion (62) at one end having a diameter disposable within the outer tubular portion (30) of the body (20) and providing an abutment surface (66) against said gasket ring (40) upon being seated; and 20 - a plurality of clinching flaps (64) extending from the other end wherein each of said clinching flaps' inner surface is - provided with gripping means (68) and - distributed to encircle a pipe end (10, 12); and - a coupling nut (80) having an inner opening (84) at one end provided with 25 internal threading (82) complementary to said body's external threading (34), and an outer opening (86) at the other end sufficient for the pipe end (10, 12) to be inserted therethrough; - at least a protrusion (38) is provided on the inner surface of the outer tubular portion (30) of the body (20) and 30 - at least a protuberance (78) is provided on the outer surface of the clinching sleeve ring portion (62) -22 whereby in mutual cooperation, said clinching sleeve's turning within said body to less than a turn.

2. A pipe coupling according to Claim 1 wherein a plurality of protrusions 5 (38) is provided.

3. A pipe coupling according to Claim 1 wherein - at least a protrusion (38) is provided on the inner surface of the outer tubular portion (30) of the body (20) and io - at least a keyway (77) is provided on the outer surface of the clinching sleeve ring portion (62) whereby said protrusion (38) is insertable into said keyway (77) and limiting said clinching sleeve's turning within said body to within keyway width. 15

4. A pipe coupling according to Claim 1 wherein the gripping means (68) provided on the inner surface of the clinching flaps (64) comprises barb edges which tips define a circumference in which a pipe end may be inserted thereinto without said barb edges cutting into said pipe end surface. 20

5. A pipe coupling according to Claim 4 wherein the clinching flaps (64) are flexed inwardly due to pressure imparted by the coupling nut's (80) inner surfaces upon tightening of said coupling nut (80) such that the barb edges securely grip upon the pipe end surface. 25

6. A pipe coupling according to Claim 4 wherein the clinching sleeve (60) is symmetrically provided with three clinching flaps (64) which inner surfaces having barbs with blunt edges. 30

7. A pipe coupling according to Claim 4 wherein each of the clinching flap (64) corners are rounded. -23

8. A pipe coupling according to Claim 4 wherein the clinching flaps (64) are separated from each other by a U-shape cut out (67).

9. A pipe coupling according to Claim 8 wherein at least one of the U 5 shape cuts' (67) extent into the ring portion (62) is different from the others.

10. A pipe coupling according to Claim 1 wherein the abutment surface (66) comprises a raised, rounded circumferential lip (73). 10

11. A pipe coupling according to Claim 10 wherein the circumferential lip (73) comprises a circumferential concave surface (74).

12. A pipe coupling according to Claim 1 wherein the coupling nut's (80) external surface are provided with longitudinal ribs (81) extending from the 15 inner opening end over at least a neck portion (83) at the outer opening.

13. A pipe coupling according to Claim 12 wherein the outer opening end (86) edge is provided with inwardly extending peripheral flange (87) thereby retaining clinching flap (64) ends within said outer opening (86) as the 20 coupling nut (80) is rotated to tighten, and wherein the remaining diameter of the outer opening (86) is sufficient for a pipe end to be inserted therethrough.

14. A pipe coupling according to Claim 1 wherein at least a bump (29) is provided in the root or between adjacent crests of the body external threading. 25

15. A pipe coupling according to Claim 1 wherein at least a depression complementary to the bump (29) is provided along the crest of the coupling nut's internal threading (82). 30

16. A pipe coupling according to Claim 1 wherein the body's inner tubular portion (28) is provided with a plurality of ribs (27) longitudinally extending -24 substantially along and symmetrically distributed around said inner tubular portion (28).

17. A clinching sleeve (60) for use in a pipe coupling, having features 5 according to any one or combination of Claims 4 - 11.

18. A body (20) for use in a pipe coupling, having features according to any one or combination of Claims 1 or 2. 10

19. A coupling nut (80) for use in a pipe coupling, having features according to any one or combination of Claims 12 - 16.

20. A pipe coupling comprising a tubular body (20), a clinching sleeve (60), a gasket ring (40) and a coupling nut (80) preassembled to accept insertion 15 thereinto a pipe end (10), wherein at least one of said tubular body (20), clinching sleeve (60) or coupling nut (80) is according to any one or combination of Claims 1 - 16.