Pipe coupling having wedge shaped keys

Abstract

A coupling and pipes joined by the coupling are disclosed. The pipes have circumferential grooves adjacent their ends which are engaged by keys that project inwardly from the couplings. The keys are wedge shaped and substantially fill the grooves to provide a rigid joint. The grooves may have a shape that is complementary to the grooves. The keys may have convex or concave cross sectional shapes. The couplings have segments attached by fasters engaging lugs at either end of the coupling. The lugs are attached pad to pad or in spaced relationship. Gaps may be maintained between various surfaces on the keys and on the grooves through tolerances on the couplings.

Description

FIELD OF THE INVENTION [0001] The invention concerns couplings for joining pipes end to end and effecting a substantially rigid or flexible fluid tight joint therebetween. BACKGROUND OF THE INVENTION [0002] Couplings for joining pipes together end to end comprise arcuate segments that circumferentially surround co-axially aligned pipes and engage circumferential grooves positioned proximate to the ends of each pipe. The couplings are also used to connect pipes to fluid control components such as valves, reducers, strainers, restrictors, pressure regulators, as well as components to components. Although in the description which follows pipes are described, they are used by way of example only, the invention herein not being limited for use only with pipes per se. It should also be noted that the term “pipe” as used herein refers to straight pipes as well as elbows, tees and other types of fittings. [0003] The segments comprising the couplings have circumferential keys that extend rad...

AI Technical Summary

Benefits of technology

[0060] Pipe couplings according to the invention incorporate the advantages of a rigid connection with a reliable visual indicator for confirming that the coupling properly engages the pipes to effect a fluid tight joint. The couplings have tolerances allowing them to be economically produced and still yield a substantially rigid joint between pipes.

Problems solved by technology

Many couplings according to the prior art do not reliably provide the desired degree of rigidity mainly because they use keys having rectangular cross-sections that are narrower than the width of the grooves that they engage.

This condition may result in inconsistent contact between the coupling and the pipes which allows too much free play and relative movement, for example, axially, rotationally or angularly, between the pipes.

It is also difficult to ensure that such keys properly engage the grooves.

Couplings which provide a more rigid connection may be ineffective to force the pipe ends apart at a desired distance from one another so that the keys and grooves are in proper alignment and the pipes are properly spaced.

The movement of the pipes, although small, is effected as the couplings are engaged with each other and the pipe and may required that significant torque be exerted upon the fasteners used to clamp the coupling to the pipes.

For such couplings, it is also difficult to reliably visibly ensure that the couplings have been properly installed so that the keys engage the grooves and the pipes are spaced apart as required to ensure a fluid tight seal.

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