1. Field of the Invention
The present invention relates generally to couplings, and in particular to pipe couplings with lock ring constructions providing resistance to the coupled pipes and conduits from being pulled out of the couplings.
2. Description of the Related Art
Couplings and fittings of various types are used for joining pipes and conduits. For example, Thompson U.S. Pat. No. 5,180,197 discloses a pipe jointing system with a tubular coupling having a rigid, outer layer receiving an elastomeric inner layer having annular ridges for pull-out resistance and sealing. Thompson U.S. Pat. No. 5,833,276 discloses a double-ended coupling with lock rings adapted for compression onto the pipe ends by lock nuts, which are threaded onto the coupling body ends. The compressive forces imparted by the lock rings restrain the pipe ends within the coupling body.
There is a significant demand for couplings that can join conduit without solvent, adhesive bonding, fusion welding or special installation equipment. For example, electrical and telecommunications conduits are commonly joined by such couplings and fittings. In recent years fiber optic cable networks have been installed in many parts of the country. Such networks are commonly buried, thus creating significant demand for couplings adapted to permanently join sections of plastic (e.g., HDPE, etc.) conduit in below-grade conditions. The fiber optic cables are commonly blown through the conduit by pressurized air, whereby the conduits and their fittings have to be able to withstand air pressures of 100 PSI or more. Water-tightness is another criterion for many such subsurface telecommunications conduit installations, which must prevent groundwater infiltration. Therefore, fiber optic cable conduit fittings are preferably fluid-tight and provide considerable resistance to pull-out. It is also preferred that they be adapted for efficient installation without tools or solvent adhesives.
Conduit sections can also be securely coupled together by providing each section with an enlarged, bell end for telescopically receiving the corresponding end of an adjacent conduit section. Similar performance criteria, such as fluid-tight construction and pull out resistance, apply to such self-joining conduit sections when they are used for fiber optic cables and other, similar applications.
Common conduit couplings for joining the ends of two adjacent conduits, such as the one described in detail in U.S. Pat. No. 5,833,276 above, and other common couplings, require an extensive amount of work to join two adjacent conduit ends using such a coupling. The typical coupling includes a “stop” or a guard in the center of the coupling. The purpose of this stop is to prevent the coupling from sliding off of one conduit end and onto another. However, this stop makes it difficult to install the coupling, and does not completely ensure that the coupling cannot slide off of either conduit end.
Heretofore there has not been available a conduit coupler system or method with the advantages and features of the present invention.
In the practice of one aspect of the present invention, a conduit coupling construction includes a coupling body threadably mounting a pair of lock nuts on its ends. Conduit ends are passed through the lock nuts and into the coupling body. Each lock nut receives a respective lock ring adapted for compression onto a respective conduit. The lock ring transforms an axial force on the conduit to a shear force to enhance gripping for pull-out resistance. The central body portion is transparent and allows an end of a conduit to pass completely through the body for more convenient installation onto two separated pieces of conduit, thereby joining them.
The drawings constitute a part of this specification and include exemplary embodiments of the present invention illustrating various objects and features thereof
As required, detailed aspects of the present invention are disclosed herein, however, it is to be understood that the disclosed aspects are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art how to variously employ the present invention in virtually any appropriately detailed structure.
Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, up, down, front, back, right and left refer to the invention as orientated in the view being referred to. The words, “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the aspect being described and designated parts thereof. Forwardly and rearwardly are generally in reference to the direction of travel, if appropriate. Said terminology will include the words specifically mentioned, derivatives thereof and words of similar meaning.
Referring to the drawings in more detail; the numeral 2 generally refers to a conduit coupling system capable of joining a first conduit end 26 with a second conduit end 28, thereby establishing a continuous length of conduit for wiring, fiber optic cable, or other common uses. Generally, this joining of two conduit ends occurs where the end of one length of conduit meets the beginning of the next length of conduit, though it could also occur at a break in a single piece of conduit, or used to join a piece of conduit that was purposefully split for repair or replacement purposes.
The lock ring 14 includes an opening 16 which allows the ring to accept a conduit and then compress around the conduit as the lock ring is closed. A number of gripping teeth 18 are molded into the inner face of the ring 14. A preferred embodiment of the locking ring 14 would include a foot 15 which allows the ring to sit against the edge of the housing body 4 or gasket 10.
Each cap 20 includes a plurality of internal threads 24 which are adapted to engage with the outer threads 8 of the housing body 4. A preferred embodiment of a cap 20 also includes a number of grips 22 which make tightening and loosening the cap 20 onto the housing body threads 8 easier on the user.
As shown in
The present invention does not have a stop, thereby making installation easier. However, without a stop, the coupler system 52 could travel along one conduit or another as the conduits shrink and expand to heat, or while being adjusted for other purposes. The locking rings 14 are therefore outfitted with gripping teeth 18 which prevent the conduit from sliding once the caps have fully engaged the housing body 4, thereby clamping the lock rings firmly down onto the conduit. In short: the conduit cannot “pull out,” and the conduit coupler system 2 cannot travel from one conduit end onto the other.
It is to be understood that while certain embodiments and/or aspects of the invention have been shown and described, the invention is not limited thereto and encompasses various other embodiments and aspects.
This application claims priority in U.S. Provisional Patent Application No. 61/788,645 filed Mar. 15, 2013, which is incorporated herein by reference.
Number | Date | Country | |
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61788645 | Mar 2013 | US |