Pipe lap joint with improved pull-apart strength

Claim 1

A coupling having improved pull-apart strength of pipe lap joints of the type comprising: an inside pipe and an outside pipe in telescoping relationship with a lap portion at the end of the inside pipe disposed inside a lap portion at the end of the outside pipe to form an overlap region, a clamping band disposed around said outside pipe at said overlap region, tightening means for clamping the clamping band around the outside pipe to clamp the pipes together, attachment means on the inside pipe beyond the overlap region of the pipes, and linking means connected between said clamping band and said attachment means, the improvement wherein: said clamping band has a cross-section including a roundish sector and a radially projecting channel-shaped sector, said channel-shaped sector comprises a pair of sidewalls extending outwardly from the roundish sector and being separated from each other at the outer ends to form an opening in the clamping band, a spline disposed between the sidewalls and having a pair of surfaces which are respectively opposite said pair of sidewalls, one of said surfaces of said spline being concave, a bar disposed against one sidewall opposite said concave surface of the spline, said tightening means including at least one bolt and nut with the bolt extending laterally through the said bar, sidewalls and spline and being adapted to force the sidewalls against the respective surfaces of the spline, whereby the clamping band is stretched around said overlap region, whereby said linking means causes binding action to resist pull-apart motion of the pipes.