A pipe coupling for coupling together two pipes or conduits of a building, comprising a sealing gasket, a housing, a clamping bolt and retaining means with which said clamping bolt tightenably engages;
- said sealing gasket being resiliently compressible and having
- a continuously annular, tubular body, which has a radial thickness, an external circumferential surface and axially opposite radial end faces and is adapted to be fitted in use as a sleeve over adjacent end portions of the two pipes or conduits to be connected end-to-end by the coupling, and
- a first wedge formation which projects radially outwardly rom said external circumferential surface and has opposed flanks presented circumferentially of said body, extending convergently away from said external circumferential surface and merging into said external circumferential surface at concavely flaring curves;
- said housing being a unitary casting of ductile metal or alloy and being in the form of a band of substantially strip form which
- surrounds said sealing gasket,
- extends through almost a circle,
- has axially opposite ends and circumferential ends,
- is of a width between its said axially opposite ends and of a circumferential length between its said circumferential ends to contain and substantially encircle said annular body of said sealing gasket,
- has a free state in which it is of an oval shape and a fully circumferentially, resiliently contracted state of a substantially true circular form,
- has internal peripheral bead formations at its said axially opposite ends, which bead formations project radially inwardly by a distance which is less than the radial thickness of said sealing gasket body and cooperate and overlap with said axially opposite radial end faces of said annular body of said sealing gasket to locate and retain said body within the confines of said band, said bead formations being interrupted at an intermediate part of the circumferential length of said band diametrically opposite to said circumferential ends, thereby to allow flexing of said band about said intermediate part,
- has an internal circumferential recess intermediate and spaced from said peripheral bead formations, and
- has a pair of opposed, radially-outwardly directed lugs at said circumferential ends, said lugs enclosing a space for receiving said first wedge formation, said lugs having radially inner ends provided with facing surfaces convexly curved complementary to and engaging with said concavely flaring curves of said first wedge formation, said facing surfaces being spaced apart, when said band is in said free state, by a distance corresponding substantially to the thickness of said first wedge formation between said concavely flaring curves;
- said clamping bolt being located with respect to and extending between said lugs, and
- said retaining means being at one of said lugs so that tightening of said clamping bolt and said retaining means causes said lugs to be urged towards one another and said band to be urged resiliently thereby towards said fully circumferentially contracted state, said gasket and said housing being constructed and arranged such that as said lugs are urged towards one another, said band is circumferentially contracted onto said sealing gasket, said sealing gasket is resiliently radially inwardly compressed, said lugs grip said wedge formation at said opposed flanks and cooperation of said convexly curved surfaces of said lugs with said concavely flaring curves of said wedge formation urges said gasket inwardly at said wedge formation thereby to restrain said body from bulging outwardly between said lugs while said band is so contracted.