Abstract:
A coupling device especially adapted for the joining of polyethylene underground irrigation hoses, having a female portion, a male portion and a lock cap, the female portion having a threaded nipple for insertion into a hose end, the male portion likewise having a threaded nipple for insertion into a second hose end and several lugs that fit into grooves in the lock cap, enabling the male portion to be pulled out of the assembly for a limited distance, for ease of fitting into difficult hose coupling situations. The presence of the lugs prevents rotation of the male portion with respect to the cap until the male portion is pulled out of the assembly far enough that the lugs are pulled past the end of the locking cap.

Description:
This application is a continuation-in-part of application U.S. Ser. No. 08/241,760, filed May 12, 1994, now U.S. Pat. No. 5,403,046. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to devices of the class used for joining fluid carrying conduits. More specifically, the invention is a coupler used to connect elastomeric irrigation tubing or hoses, meaning either the connecting of two lengths of tubing or hose to each other, or the connecting of one tube or hose to a threaded plumbing fixture. 
     Underground lawn sprinkling systems and other underground irrigation systems generally are comprised of varying lengths of polyethylene hose or tube. Although polyvinyl chloride (PVC) tube is a widely used material for interior plumbing systems, PVC is not suitable for such underground systems in all climates, as PVC is rigid and cannot accomodate changes in dimension caused by freeze-thaw cycles. The PVC pipe system must be drained of all water every cold season by draining or blowing, in order to prevent rupture by the expansion of frozen water. Polyethylene can, however, accomodate such temperature changes, so it has become the predominant material in such underground systems. Polyethylene poses a problem for installers and repairers, though. After underground installation, whenever it is necessary to join two lengths of polyethylene tube or hose, a coupling must be used, of the type that has two nipples to fit into each end of the hoses to be joined. To install the coupling, the installer very frequently has to lift and gently bend one end of hose, in order to shorten that length of hose enough to fit over the end of a nipple and then be pushed over the length of the nipple. Even if due care is exercised in the installation, while so bending the hose it often kinks, which substantially weakens the integrity of polyethylene hose. This in turn necessitates expensive and time consuming hose replacement and further repair. 
     Therefore, there is a need for a coupler that can be installed in such polyethylene irrigation systems without the need to bend up one of the hose sections to be joined and run the risk of kinking the section. It is the primary object of the present invention to meet this need by providing a coupling that can be dimensionally shortened to fit into a gap between two sections of hose to be joined, and then be dimensionally lengthened so that each nipple can be thrust into each of the hose ends. The present invention accomplishes this by the use of a three component assembly, namely an outer or female nippled component, an inner or male nippled component and a locking cap. The inner component can slide with respect to the outer component, thus shortening or lengthening the complete coupling. Thus, the assembled coupling can be placed in a cut gap between two lengths of hose, one nipple can be inserted into the first end of hose and the coupling can be pulled out or expanded so that the second nipple can be inserted into the second hose end. By being able to expand in length, the coupling does away with the need to lift and bend one end of hose, eliminating that as a source of potential hose kinks. 
     Another object of the invention is to be able to securely affix a lock cap without the need for adhesives. This has been accomplished by the use of the technique of untrasonic welding. This feature eliminates the need for adhesives, which are toxic, expensive and messy to handle. 
     SUMMARY OF THE INVENTION 
     The invention is a coupler for joining elastomeric hoses, comprising: firstly, an outer tubular coupling member having a longitudinal axis and distal and proximal ends; having a nipple at the distal end for sealably seating within a predetermined length of a first elastomeric hose to be joined; with at least a portion of the internal diameter of the outer tubular coupling member being of a suitable dimension to telescopically receive an inner tubular coupling member; secondly, an inner tubular coupling member having a longitudinal axis and distal and proximal ends; having a nipple at the distal end for sealably seating within a second elastomeric hose to be joined to said first elastomeric hose; at least one annular groove at the proximal end for receiving a ring shaped distortable sealing member; and a plurality of projections on the outer surface of said inner tubular coupling member, the projections circumferentially arrayed on said inner tubular coupling member; the proximal end of said inner tubular coupling member fitting telescopically inside of the proximal end of said outer tubular coupling member; and thirdly a substantially tubular locking cap member having a longitudinal axis and distal and proximal ends; having an internal diameter of a suitable dimension to telescopically fit over said inner tubular coupling member such that said locking cap, when fitted over said inner tubular coupling member comes into juxtaposed contact with said outer tubular coupling member after assembly of the cap, the inner tubular coupling member and the outer tubular coupling member; said locking cap additionally having a plurality of substantially longitudinal grooves in the locking cap&#39;s inner surface of sufficient dimension to slideably receive said plurality of projections on said inner tubular coupling member to prevent rotational movement of the inner tubular coupling member with respect to the cap, yet allowing such rotational movement when, after assembly of the cap, the inner tubular coupling member and the outer tubular coupling member, at least a portion of the inner tubular coupling member is pulled along a substantially longitudinal axis for a sufficient distance such that said projections are pulled past the end of said cap, thereby allowing such rotational movement. 
     An alternative preferred embodiment of the invention, that can either be used to join one elastomeric hose or tube to another or to join an elastomeric hose or tube to a plumbing fixture comprises firstly an outer tubular coupling member having a longitudinal axis and distal and proximal ends; having a nipple at the distal end for sealably seating within a predetermined length of a first elastomeric hose to be joined, said nipple beating on its outer surface a plurality of saw-toothed parallel threads; a flange against which an end portion of said elastomeric hose abuts; with at least a portion of the internal diameter of the outer tubular coupling member being of a suitable dimension to telescopically receive an inner tubular coupling member; and an internal surface flange against which said inner tubular coupling member abuts; secondly an inner tubular coupling member having a longitudinal axis and distal and proximal ends; having a nipple at the distal end for sealably seating within a predetermined length of a second elastomeric hose to be joined to the first elastomeric hose, said nipple bearing on its outer surface a plurality of saw-toothed parallel threads, or for sealably seating within a threaded fluid-carrying fixture, in which case said nipple bears on its outer surface a plurality of helical threads; at least one annular circumferential groove at the proximal end for receiving a ring shaped distortable sealing member; and a plurality of lugs on the outer surface of said inner tubular coupling member, the lugs circumferentially arrayed on said inner tubular coupling member; the proximal end of said inner tubular coupling member fining telescopically inside of the proximal end of said outer tubular coupling member; and thirdly a substantially tubular locking cap member having a longitudinal axis and distal and proximal ends; having an internal diameter of a suitable dimension to telescopically fit over said inner tubular coupling member such that said locking cap, when fitted over said inner tubular coupling member comes into juxtaposed contact with said outer tubular coupling member after assembly of the cap, the inner tubular coupling member and the outer tubular coupling member; said locking cap additionally having a plurality of substantially longitudinal grooves in the locking cap&#39;s inner surface of sufficient dimension to slideably receive said plurality of lugs on said inner tubular coupling member to prevent rotational movement of the inner tubular coupling member with respect to the cap, yet allowing such rotational movement when, after assembly of the cap, the inner tubular coupling member and the outer tubular coupling member, at least a portion of the inner tubular coupling member is pulled along a substantially longitudinal axis for a sufficient distance such that said projections are pulled past the end of said cap, thereby allowing such rotational movement. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal central cross section view of two lengths of hose connected by a preferred embodiment of the invention, not to scale. 
     FIG. 2 is a longitudinal cross section in side view, showing the outer tubular coupling member, not to scale. 
     FIG. 3 is a longitudinal cross section view showing the outer tubular coupling member, not to scale. 
     FIG. 4 is a longitudinal side view of the locking cap with its sealing flange, not to scale. 
     FIG. 5 is a cross section view of the locking cap, taken through the thicker diameter of the cap, showing the grooves for receiving the external lugs of the inner coupling member, not to scale. 
     FIG. 6 is a perspective view of the locking cap, featuring the slots in the cap for receiving the lugs on the inner coupling member, not to scale. 
     FIG. 7 is a longitudinal cross section view showing the inner coupling member, not to scale. 
     FIG. 8 is a side view showing the inner coupling member and featuring external lugs on the surface, not to scale. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     At FIG. 1 there is shown in cross section the assembled coupler of the present invention, with hoses or tubes 2 shown fitted over the nipples 11 and 31. It can be seen that the entire coupling assembly is made up of three components: the outer tubular coupling member 3, which can be seen to be a cylinder or female type coupling member; the inner tubular coupling member 5, which can be seen to be a piston or male type coupling member; and the end plug locking cap member 7. 
     The outer tubular coupling 3 is shown in FIGS. 2 and 3, where it can be seen to be a substantially tubular component. The nipple 11 preferably bears a plurality of circumferential parallel threads 9 that tend to grip into the relatively soft material of an elastomeric hose. Most preferably, the threads 9 are a sawtooth pattern in profile, that permits ready fitting of the end of a hose over the nipple up to the hose abutment flange 17, but resists pulling the same hose end off of the nipple 11. The outside diameter of the nipple 11 is a slight degree larger than the inside diameter of the hose to be connected, and outside diameters of the nipple 11 are molded in sizes that comport to industry standards for hoses. In a more preferred embodiment of the invention, the outer barrel 14 of the outer tubular coupling 3 has molded or otherwise fixably mounted thereon a plurality of ribs 15 that run substantially in a longitudinal axis parallel to the longitudinal axis of the coupling assembly. The ribs 15 are an aid to the installer or repairer to get a better grip on the outer tubular coupling 3, which, since it is preferably molded plastic, will be slippery if wet. In an alternative embodiment of the invention the outer barrel 14 has molded thereon a plurality of nubs or other raised surface shapes, or has molded thereon a roughened surface to increase friction. 
     In a most preferred embodiment, the proximal end of the outer tubular coupling 3 fits over a portion of the barrel of the end cap 7, as shown in FIG. 1, thus helping form a seal. There are a large variety of ways that outer coupling 3 can come into such juxtaposed contact with the end cap 7, and the invention in not to be limited to the particular configuration depicted in FIG. 1. In particular, there is no critical length of cap 7&#39;s barrel, or the rabbet in the interior of outer coupling member 3 that accomodates any portion of the length of the cap&#39;s barrel. 
     The inner tubular coupling 5 is shown in FIGS. 1 and 7, where it can be seen to be a substantially tubular component. Its nipple 31, like the nipple 11 on the outer coupling 3, preferably bears on its distal end a plurality of circumferential threads 9 that most preferably are a sawtooth pattern in profile. In an important alternative embodiment of the invention, the threads 9 on the distal end of the inner tubular coupling member 5 can be helical instead of parallel, so that the coupling can be screwed into a plumbing fixture having a suitably threaded bore. 
     The inner coupling has, at its proximal end, at least one annular groove 35 (FIG. 7) for receiving a ring shaped distortable sealing member, which most preferably is an O-ring 33 (FIG. 1) made of a suitable rubber or plastic compound. Depending on the application in question, more than one annular groove and O-ring can be fabricated on the inner coupling. The inner tubular coupling member 5 can be pushed into the outer tubular coupling member 3 until the abutment flange 37 is reached. 
     The inner tubular coupling member 5 has a plurality of projections 39 circumferentially arrayed on its outer surface, as shown in FIG. 8. These are preferably molded lugs. Most preferably, there are three lugs that are substantially cuboidal in shape and are uniformly arrayed. The lugs will most advantageously be formed relatively close to the threads 9. 
     The cap member 7 is shown in FIGS. 1, 4, 5 and 6. The cap is substantially tubular, and features an abutment flange that serves to form a sealing abutment for both the end of an elastomeric hose or tube on one side of the flange, and the proximal end of the outer coupling member 3 at the other side of the flange. 
     The cap 7 additionally has a sufficient number of grooves 55 formed therein so as to allow the projections 39 to slideably move through the grooves 55 when the inner coupling member 5 is pulled or pushed through the cap 7. Most preferably, these grooves 55 open to the distal end of the cap 7, as shown in FIG. 6, but not to the proximal end. 
     In the most preferred method of operation, the cap member 7 is telescopically pushed pan way onto the inner coupling member 5 so that the grooves 55 open towards the threads 9. The grooves slide over the projections 39. The nipple 31 is fitted in a section of hose or tube to be joined, or in the embodiment having helical threads, is screwed into a plumbing fixture threaded bore. Then, the outer coupling member 3 is telescopically fitted onto the proximal end of the inner coupling member 5 and the cap 7 is pushed onto the proximal end of the outer member 3 until stopped or juxtaposed against the complementary surfaces of the outer member 3, positioning the cap in place. The assembled coupler 1 is then lengthened by pulling the outer member 3 away from inner member 5 as nipple 9 is inserted into the second end of hose or tube to be joined. It should be noted that while the projections 39 are engaged in the grooves 55, the cap cannot rotate with respect to the inner member 5. Whenever the inner member 5 is pulled past the end of cap 7, the projections 39 do not engage the grooves 55 and the cap 7 can rotate with respect to the inner member 5. The cap 7 is then fixed permanently in place by the method of ultrasonic welding, which is well known to workers in that art. Ultrasonic welding permanently fixes the cap in place by causing the thermoplastic materials of the component pieces to meld and then cure in an agglomerated whole. 
     Although by virtue of the use of ultrasonic welding the locking cap can be permanently affixed without the need for adhesives, such adhesives can still be used. The adhesive of choice for the PVC type of coupling is methyl ethyl ketone. There is an alternative embodiment of the invention that does not feature the spring biased tabbed prongs, and it would be entirely appropriate to use adhesive to lock the cap in place. In yet another embodiment of the invention, an annular groove is caused to be formed between the female member abutment flange 47 and the cap abutment flange 21 providing a suitable channel for liquid adhesive to be injected into, allowing the adhesive to run into the contact area between the interior of the cap 7 and the exterior of the female member 3. 
     The coupling components can most economically be made by injection molding techniques well known to those of ordinary skill in the plastics art. The most preferred material for molding the coupling components is PVC. Although PVC is unsuitable for use as underground conduit for water due to the aforementioned problems with it being unable to accomodate temperature changes, the relatively short length of the coupling in relation to the overall length of the conduit system of which it is a part means that shrinkage and expansion due to temperature changes will be adequately accomodated by the polyethylene hoses, minimizing stress on the coupling. 
     While the invention has been described and illustrated with reference to certain preparative embodiments thereof, those skilled in the art will appreciate that various changes, modifications and substitutions can be made therein without departing from the spirit and scope of the invention. It is intended, therefore, that the invention be limited only by the scope of the claims which follow, and that such claims be interpreted as broadly as possible.