Patent ID: 6412824
Filing Date: 2002-07-02
Classification: F16L

Abstract:
A mechanical coupling for connecting a branch pipe to a main pipe at a hole through the wall of the main pipe, comprising:a. opposed first and second arcuate sections defining a cylindrical space therebetween for embracing the wall of the main pipe; the first of the arcuate sections including a concave saddle wall, defining a portion of a cylindrical surface having a radius generally corresponding to the outer circumference of the main pipe, a radially extending branch pipe opening within the first arcuate section, dimensioned to overlay the main pipe opening and communicate with the saddle wall, and a spigot wall surrounding the branch pipe opening, and terminating at the saddle wall; b. a radially extending gasket recess, surrounding the spigot wall, the gasket recess having a radially inward opening terminus at the saddle wall, and a radially outward wall terminus in the direction of the branch pipe; c. a gasket for sealing engagement within the gasket recess and the main pipe, the gasket including: i. a first generally circumferential sealing surface at one radial end terminus of the gasket, positioned along the radially inward open terminus of the gasket recess for engagement with the outer circumference of the main pipe proximate the spigot wall, and providing a continuation of the saddle wall, ii. a second generally circumferential sealing surface of the opposed radial end terminus of the gasket, in engagement with the radially outward wall terminus of the gasket recess, and iii. a third generally circumferential sealing surface, radially intermediate the first and second generally circumferential sealing surfaces, in engagement with the saddle wall, whereby the gasket provides radially spaced first, second and third generally circumferential sealing surfaces; and iv. a generally radial step between the second and third surfaces to provide a fourth generally radial sealing surface, the fourth generally radial sealing surface being in engagement with a generally radial sealing surface of the gasket groove opposite the spigot wall; such that the second sealing surface includes an annular pressure slot to bifurcate the second sealing surface and provide first and second radial wall surfaces, a first of the radial wall surfaces opposing the spigot wall, and a second of the radial wall surfaces forming the opposed radial wall of the fourth sealing surface; d. pressure transmission means for transmitting the pressure from within the main pipe to the annular pressure slot to urge the first and second radial wall surfaces in sealing engagement with opposed wall surfaces of the spigot wall and gasket groove; and e. fastening means for detachably fastening the first and second arcuate sections to one another in embracing relationship around the wall of the main pipe.