Patent ID: 7252310

Claim:
A pipe coupling for connecting two pipe ends, comprising: a clamp band extending circumferentially from a first end to a second end; a tightening mechanism located at said first and second ends of said clamp band, said tightening mechanism including at least one fastener to tighten said clamp band by drawing said first and second ends towards each other; and a split sealing sleeve located radially inside said clamp band in contact with said clamp band, said split sealing sleeve having first and second circumferential ends in confronting relationship for contact with each other when said sealing sleeve is collapsed circumferentially by tightening of said clamp band, said sealing sleeve including at least one tongue and groove sealing joint, said groove being defined at one circumferential end of the sealing sleeve and said tongue being defined at the other circumferential end of the sealing sleeve, said tongue being disposed opposite said groove for mating with said groove when said sealing sleeve is collapsed circumferentially, the tongue and the groove each having first and second side edges, the first side edge of the tongue and the first side edge of the groove being a first mating-pair of side edges, the second side edge of the tongue and the second side edge of the groove being a second mating-pair of side edges, said tongue having a non-locking interference fit with said groove throughout a range of penetration extending from initial engagement to a point of maximum penetration for both of said mating-pairs, wherein a central portion of at least one of said first side edges is non-parallel relative to a circumferential centerline of said sleeve, said sealing sleeve including a relief slot adjacent one of said first side edges forming a spring member which yields in response to penetration of said tongue into said groove, the width of said tongue before insertion into said groove being greater than the width of said groove, wherein forceful penetration of said tongue into said groove during tightening of said clamp band causes engagement of said non-parallel first side edges with each other and said second side edges with each other which, during further tightening of said clamp, causes said sealing sleeve to deform at said relief slot as said tongue penetrates into said groove.