COUPLING

BACKGROUND

[001] The present disclosure relates to a coupling, in particular a pipe coupling for use in irrigation.

[002] Such a coupling may be provided with sharp teeth in order to grasp onto a pipe. For example, US patent 5,951,058, the disclosure of which is incorporated herein by reference, describes a joint used for joining pipes which may carry water. The joint is provided with a gripper ring having circumferential teeth made of hard material, such as acetal resin, so that the teeth can bite into the outer surface of a polyethylene pipe. [003] US patent 1,994,784, the disclosure of which is incorporated herein by reference, describes a coupling for connecting two sections of a water conducting hose. The coupling has a nipple with a sharp gripping edge which, when inserted into the hose, forms a sharp bend in the inner surface of the hose. This prevents the coupling and hose from being pulled apart. [004] Water used for irrigation may often contain plant nutrients and other materials which may damage elements made of relatively hard plastic materials, such as acetal resin, which are generally expensive. A generally preferred plastic material used for irrigation applications and products, which is relatively cheap and resistant to damage caused by nutrients and other materials carried by irrigation water, is polyolefin material. However, polyolefin material is a relatively soft and is not suitable for forming a sharp rigid gripping edge which maintains its shape under pressure.

SUMMARY

[005] The following embodiment and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope.

[006] In an embodiment, a coupling comprises at least one nipple for connection with an end of a pipe, the nipple comprising a barb member and a ring, the barb member comprising a forwardly tapering head, a neck and a rearwardly facing shoulder, the neck forming an obtuse angle with the head, the ring comprising an internal bore wherein in a connected state of the coupling, the nipple is located in the bore and at least a portion of the end of the pipe is pressed between a forwardly tapering collar of the bore and the barb member.

[007] In an embodiment, the barb member is formed from a relatively soft plastic which is optionally polyolefin and the pipe is optionally an irrigation pipe. [008] In an embodiment, the neck has a width T having optionally a value less then or equal to 0.5 mm and optionally greater then or equal to 0.1 mm. [009] In an embodiment, the neck and at least a portion of the head of the barb member press against the at least portion of the end of the pipe. [010] The above embodiments provide also the advantage that a coupling made of relatively soft inexpensive material which is resistant to damage by irrigation water may be used also optionally in high pressure irrigation systems. [011] In addition to the exemplary aspects and embodiment described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed descriptions.

BRIEF DESCRIPTION OF THE FIGURES

[012] Exemplary embodiments are illustrated in referenced figures. It is intended that the embodiments and figures disclosed herein are to be considered illustrative, rather than restrictive. The disclosure, however, both as to organization

and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying figures, in which:

[013] Fig. 1 shows a perspective view of a coupling in accordance with the present disclosure connected to two ends of pipes;

[014] Fig. 2 shows an exploded perspective view of the coupling with the pipes removed;

[015] Fig. 3 shows a cross sectional view of a ring of the coupling shown in

Fig. 1 taken in the plane P-P; [016] Fig. 4 shows a side of a sleeve of the coupling; [017] Fig. 5 shows a section of Fig. 4;

[018] Fig. 6 shows a partial cross sectional view of the coupling shown in Fig. 1 taken in the plane P-P; and [019] Fig. 7 shows a section of Fig. 6. [020] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated within the figures to indicate like elements.

DETAILED DESCRIPTION

[021] Attention is first drawn to Figs. 1 and 2 showing a coupling 10 having a longitudinal axis A and comprising a sleeve 12 and two identical rings 14. The sleeve 12 has two identical axially extending nipples 16 and an annular bulge 18 therebetween. In a connected state of the coupling 10, each nipple 16 may connect together with one of the rings 14 to an end portion of an irrigation pipe 20. An axial forward direction of the axis A is defined in a direction away from the bulge 18. [022] The coupling 10 in general is formed by injection molding from relatively soft inexpensive polyolefm material, optionally polyethylene and

A-

preferably polypropylene. The material of the coupling 10 which is relatively resistant to damage by nutrients and chemicals typically carried by water used in irrigation, may be reinforced by fillers which may optionally be in the form of glass micro-spheres, talc or clay, and preferably in the form of fibers such as glass, carbon or mineral. The irrigation pipe 20 in general is formed by extrusion from plastic such as polyethylene.

[023] It should be noted that directional terms appearing throughout the specification and claims, e.g. "forward", "rear" etc., (and derivatives thereof) are for illustrative purposes only, and are not intended to limit the scope of the appended claims. In addition it is noted that sleeve 12 and rings 14 of the coupling 10 and the end portion of the pipe 20 will be described herein in their respective orientation in the connected state of the coupling 10 and therefore in relation to the axis A. [024] Attention is now drawn to Fig. 3. Only one of the rings 14 will be described herein due to the fact that both rings 14 are identical. A bore 22 having a peripheral bore face 24 extends along the axis A through the ring 14 and opens out to a rear and a forward end of the ring 14. An internal thread 26 and a collar 28 are formed on the bore face 24. The internal thread 26 is located adjacent the rear end of the ring 14 and the collar 28 is located adjacent the forward end of the ring 14. The collar 28 tapers forwardly and has a shape of a truncated cone having a cone angle α.

[025] Attention is now drawn to Figs. 4 and 5. Each nipple 16 has a rear stem 30 and a forward barb member 32. An external thread 34 is formed on a peripheral surface of the stem 30 adjacent the bulge 18. The barb member 32 has, on a peripheral surface thereof, a forward head 36, a rear shoulder 38, a neck 40 therebetween and an annular rim 42 formed at an intersection of the shoulder 38 and neck 40. The head 36 tapers forwardly and has a shape of a truncated cone having a cone angle β. The neck 40 forms an internal obtuse angle δ with the head 36, has a width T measured in a direction along the axis A and may have an axially extending

cylindrical shape or optionally a forwardly tapering truncated cone shape having a cone angle γ (γ not indicated in figs.). The shoulder 38 faces rearwardly. [026] By way of a numerical example: α, β and γ satisfy a relationship of β > α and α > γ > 0°; optionally 0.5 mm > T > 0.1 mm, 30° > α > 10°, 40° > β > 20°; and preferably 0.3 mm > T > 0.2 mm, 25° > α > 15°, 35° > β > 25°.

[027] Attention is now drawn to Figs. 6 and 7. The sleeve 12 has a cavity 44 which passes therethrough along the axis A. In a non-connected state of the coupling 10 (not shown), the ring 14 is located in a forward position in relation to its respective nipple 16 in order to enable the end portion of the pipe 20 to first pass rearwardly through the bore 22 and then slide rearwardly and expand over barb member 32. The ring 14 is then urged rearwardly until its internal thread 26 reaches threading engagement with the external thread 34 of the nipple 16. From this position the ring 14 is screwed onto the nipple 16 until reaching the connected state of the coupling 10. In the connected state, a first section 46 of the pipe 20 is pressed between the collar on the one side and the neck 40 and at least a portion of the head 36 on the other side. This urges a second section 48 of the pipe 20, located rear to the first section 46, to bend over the rim 42 and slightly expand rear to the rim 42 to form a firm grip of the pipe 20 in the coupling 10. [028] It is noted that the neck 40, in accordance with the present disclosure, provides the relatively soft material of the barb member 32 on the one hand with sufficient rigidity to withstand forces imposed thereupon and on the other hand with the required "sharpness" at the rim 42 to grip onto the pipe 20. The internal obtuse angle δ between the neck 40 and the head 36 strengths a vicinity of the barb member 32 adjacent the intersection of the neck 40 and the head 36, which is most exposed to forces imposed thereupon by the ring 14 in the connected state and which is required to exhibit the aforementioned "sharpness".

[029] It has been found that with the construction of the coupling 10 in accordance with the present disclosure and optionally with the dimensions T, α, β, γ and δ being within the ranges specified hereinabove, the efficiency of the coupling

10 in terms of its ability to hold on to the pipe 20 and withstand tensile forces, is significantly increased as compared with hitherto known couplings. Tests indicate that the coupling 10, in accordance with the present disclosure, may be used in high pressure irrigation systems having a water pressure of at least up to 40 meters above atmospheric pressure. This is without having any additional means that contact the pipe 20 on each nipple 16, besides the one barb member 32 and/or without having any additional annular means, to the nipple 16 and pipe 20, besides the ring 14. Additional means which are typical to couplings designed to operate in high pressure irrigation systems. [030] Thus, the coupling 10 in accordance with the present disclosure has an overall compact structure which may be favorable when the coupling 10 is optionally used to join together irrigation pipes, such as optionally drip irrigation pipes, of different lengths when setting up an irrigation system. Typically, at an end of the use of such irrigation system in a field; the pipes are rolled onto a spool (not shown) in order to be re-used later on. A coupling 10, as in the present disclosure, which on the one hand efficiently holds pipes 20 together and on the other hand is compact; is an advantage when being rolled onto the spool.

[031] It is noted, that whereas the coupling 10 described hereinabove is configured to connect to two ends of pipes 20 and therefore has two coaxial nipples 16, a coupling 10, in accordance with an embodiment of the disclosure, can be configured to connect to more than two irrigation pipes 20. For example, a coupling 10 in accordance with an embodiment of the present disclosure can comprise a configuration of plurality nipples 16, such as a "T" or a "star" configuration. A coupling 10 in accordance with an embodiment of the present disclosure may also have only one nipple 16, joined integrally or non-integrally to an irrigation apparatus such as a sprinkler or a valve, which connects the apparatus to an end portion of an irrigation pipe.

[032] Although the present embodiment has been described to a certain degree of particularity, it should be understood that various alterations and modifications

could be made without departing from the scope of the disclosure as hereinafter claimed.