Pipe coupling with tongue and groove sealing sleeve

A pipe coupling for securing a pair of coaxial pipe ends, comprising:

• a generally cylindrical split sealing sleeve for collapsibly fitting over the pipe ends, said sleeve includes an inner surface for contacting an outer surface of at least one of the pipes, an outer surface, a first end having a tongue, and a second end having a groove such that when said first and second ends are drawn together said tongue and groove oppose one another;
• said tongue forms a non-locking interference fit with said groove and includes first and second spring members separated by a relief slot, wherein each of said spring members includes at least one convergent side edge;
• said groove receives said tongue during formation of said non-locking interference fit and includes a plurality of convergent side edges that complement said side edges of said spring members;
• a generally cylindrical clamp band for collapsibly fitting over at least a portion of said split sealing sleeve, said band includes an inner surface for contacting said sleeve outer surface, a first band end, and a second band end, and;
• a tightening mechanism located at said first and second band ends for drawing said band ends together, wherein during formation of said non-locking interference fit said tongue penetrates said groove such that:
• i) said convergent side edges of said spring members engage said convergent side edges of said groove, ii) said first and second spring members are deflected towards each other, iii) said relief slot is deformed in response to said deflection, and iv) said side edges of said spring members and said groove form a seal against the outer surface of at least one of the pipes.