AU594831B2 - Pipe fittings - Google Patents

Description

g COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-62 3 NOV 1987 Adelaide 594" 594831 COMPLETE

SPECIFICATION

(ORIGINAL) FE STAMP TO VALUE O AFORL OFIRFFICE USE: FOR OFFICE USE: Application Number: Lodged: Class Int. Class Comp ete Specificatior Lodged: Accepted: Published: Priority: R.elaj$d Art: o TO BE COMPLETED BY APPLICANT Name of Applicant: BRIDGES CORPORATION PTY LTD Address of Applicant: 503 Grand Junction Road, Wingfield, State of South Australia, Commonwealth of Australia Actual Inventor: LYALL JOHN CAUSBY and GEOFFREY PETER KASTELEIN Address for Service: R K MADDERN ASSOCIATES, 345 King William Street, Adelaide, State of South Australia, Commonwealth of Australia Complete Specification for the invention entitled: "PIPE FITTINGS" The following statement is a full description of this invention, including the best method of performing it known toxa us.

IF3 2M 5/85 This invenrtion relates to a pipe fitting which is useful for securing to a polymeric pipe, and particularly useful for securing to a thermoplastic pipe, for example a thin walled thermoplastic pipe which can be used for trickle irrigation, a hose or other article wherein it is desired to expand the pipe or article over a ridge on the fitting and retain it against displacement due to the effects of temperature pressure or mechanical forces.

10. BACKGROUND OF THE INVENTION oe Because of costs, use of very thin wall pipe, formed S from flexible polymeric material, has become common in drip irrigation systems for the drip tubes, this thin wall pipe itself being connected to a sub-main (or a main) pipe which is often a pipe also formed from a flexible polymeric material which, except when in use, has two opposite walls contiguous with one another so 0 that it lays flat. The drip tube is also similarly S. arranged, but of course much smaller in size.

PRIOR ART ee *There are two types of connectors which are presently employed to connect the drip tubes to the submains of the main pipes of irrigation systems, the first so 9& being a connector wherein a cam or thread between a relatively fixed and relatively movable part of the fitting will urge the drip tube back towards a barbed surface of a ridge surrounding a tail on the fitting.

This is subject to the disability that the drip tube frequently is inadvertently rotated, resulting in a restriction to the water passageway, and this in turn results in loss of time in a job which is essentially repetitive.

The other type of fitting which is commonly used merely slides a ring backwardly, the ring urging the end of the drip tube against the barb surface (or possibly a ramped face), but this is generally unsatisfactory in that under some conditions the inter- -2- L~L h~L1-LY- 1

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engagement is insufficient to ensure retention and the drip tube can break away. This particularly applies on a hot day when excessive pressure is applied, or the drip tube is subject to a mechanical force.

Other but less relevant prior art known to the applicant include U.S. Patent 3,833,246 Wake, Australian Patent 547,580 (90326/82) Plasson, Australian P.C.T.

application W.O. 83/00206 Tucker, Australian Patent 548,227 (11725/83) Kisiel, and Australian application 47528/85 Fouts.

BRIEF SUMMARY OF THE INVENTION ko With the object of providing an improvement over 0:00 known prior art fittings for securing the end of a drip ~tube to a sub-main or main of an irrigation system, or 35. for other purposes analogous thereto, in an embodiment of this invention a fitting comprises a head, a tail extending downstream of the head, an annular ridge surrounding the tail downstream of the head, and a male thread between the ridge and the head. A nut has a number of resilient spaced fingers extending upstream from an aoooo 2 0. outwardly diverging mouth, the fingers having portions of a female thread which engage the male thread to resist upstream movement of the nut, but which can slide S• ("ratchet") over the male thread if the nut is moved in a downstream direction.

The fitting is formed from material having some degree of resilience and yield and after the tail has been inserted into a thin wall tube, so that the tube extends over the ridge and upstream of the barb surface, the nut can be caused to slide in a downstream direction so that thc surface of its mouth end urges the thin wall tube into engagement with the barb surface of the ridge, and then by slight rotation, the nut will apply a "final clamp" against a tube. Although sliding operation can be effected with a standard form Whitworth or SAE type thread, the "final clamp" is very much more effective if the thread has a buttress (sawtooth) section.

-3- .C .il L r i. Li~ One of the problems, as said above, is to ensure that rotation of the nut will not cause twisting of the thin wall polymeric tube, but by this invention the rotation of the nut is so small that any pipe rotation is negligible. Further, in an embodiment of this invention, the thread on both nut and head is either a single or a multi-start buttress thread which thereby does not impart any effective spreading force to the fingers which a section thread might otherwise cause them to deflect radially outwardly to a disengagment

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Because of the repetitive nature of attaching drip tubes to a main or sub-main in an irrigation system, go 0 0 or to a drip or spray outlet fitting, quite often the drip tube is not positioned sufficiently far onto the tail of the main body of the fitting, and in an Woembodiment of this invention the nut is provided with a space between adjacent fingers which provides an immediate vision of the extent to which the drip tube has passed beyond the barb surface of the ridge on the body.

e, o The upstream end of the body can occupy any one of a number of shapes depending upon the use to which S" the fitting is to be applied. It can for example comprise a female thread which is engageable over a threaded spigot of an anchor inserted into the sub-main or main.

It can however alternatively be provided with an externally threaded spigot, a plug-in type connector or other fitting.

As said, the pipe fitting of this invention has a wide range of uses, but the following description relates specifically to the use of the fitting with respect of thin walled thermoplastic pipe such as is used for example for the lateral drip tubes which extend from a sub-main in a drip irrigation system.

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9* BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention is described hereunder in some detail with reference to and is illustrated in the accompanying drawings in which FIG. 1 is an exploded perspective view of an assembly of body and nut, FIG. 2 is a side elevation of the assembly, FIG. 3 is a view corresponding to FIG. 2 but partly sectioned, 10. FIG. 4 is an end elevation of the body of FIG. 2 but shown in third angle projection, FIG. 5 is an end elevation of a nut also shown in third angle projection, and FIG. 6 is an enlarged section showing how the nut 15. clamps a tube to the tail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In this embodiment, a fitting 10 comprises a body S 11 and a nut 12. The upstream end of the body 11 contains a female thread 13 by which it is securable to the anchor for a sub-main or main of an irrigation system. The S upstream end also comprises a head 14 including a plurality of finger grips 15, and downstream from this the cuter surface of the tail comprises a male buttress thread 16, and downstream beyond that the tail is provided a ridge 17 the upstream end of which is a barb surface 18 and downstream end a tapered surface 19. The nut 12 also has finger grips 15, these being downstream from a plurality of circumferentially spaced fingers 22 the upstream ends of which contain a female buttress thread 23 which can engage over the male thread 16, either by sliding in a downstream direction, or rotating.

The fingers are resilient for this purpose. The downstream end of nut 12 terminates in an outwardly diverging mouth surface 26. However, the mouth surface need not necessarily diverge outwardly, but could comprise a generally cylindrical surface terminating in a radially inwardly directed surface at its upstream end, but this shape is not illustrated.

A pair of spaces 24 exist between fingers 22 for vision purposes.

When a drip tube 28 (FIG. 6) is positioned over ridge 17, the nut 12, which is screwed fully onto male thread 16, can be pulled back axially due to the resilience of the fingers allowing the female thread to ride over the male thread, and the nut 12 is then rotated by a small angle to provide a "final clamp" force urging the tube 26 against barb surface 18.

10. If the body 11 is the body of an outlet fitting, such as a dripper, the words "upstream" and "downstream" in the above description should be interchanged.

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Claims (1)

1. 9.9. direction, the inner surfaces of said fingers comprising female thread portions engageable with said male thread, the nut having an inner surface at its downstream end defining a mouth which surrounds said ridge: the profiles of said thread being such that said S'* 00 female thread portions of said fingers are slidable over said male thread upon axial movement of the nut over the 999999 Ss tail in a downstream direction, but resist axial movement of the nut in an upstream direction except upon nut rotation, such axial movement varying a tube clamping space between the barb ridge and the mouth. 2. A pipe fitting according to claim 1 wherein said mouth surface diverges in a downstream direction. 3. A pipe fitting according to claim 1 or claim 2 wherein said thread profiles are of buttress shape. 4. A pipe fitting according to claim 3 wherein said thread is a single start thread. A pipe fitting according to claim 3 or claim 4, wherein said thread is a multi-start thread. -7- I i iiii.iil-i. .l -I~ 6. A pipe fitting according to any preceding claim wherein said fingers extend in an axial direction and are circumferentially spaced from each other, at least two adjacent fingers being spaced apart sufficiently to provide a vision space of said pipe where it surrounds said tail. 7. A pipe fitting according to any preceding claim wherein said head and said nut both have finger grips surrounding them. S. 8. A pipe fitting according to any preceding claim wherein said thread comrises a female thread in its upstream end. 9. A pipe fitting according to any preceding claim with annular gripping rings within the nut. A pipe fitting substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. DATED this 3rd day of NOVEMBER, 1987 BRIDGES CORPORATION PTY LTD By its Patent Attorneys R K MADDERN ASSOCIATES -8- r