collars 250 engage the outer surface of the body 235 to limit the inward radial movement of the gripping elements 205 preferably a biasing member 255 is disposed between the collar and the body 235 to bias the gripping element 205 away from the body 235 in one embodiment the biasing member 255 may be a spring the interior surface of the gripping element 205 includes one or more engagement members 206 in one embodiment each engagement member 206 is disposed in a slot 215 formed in the interior surface of the gripping element 205 preferably the engagement members 206 are pivotable in the slot 215 the portion of the engagement member 206 disposed in the interior of the slot 215 may be arcuate in shape to facilitate the pivoting motion the tubular contact surface of the engagement members 257 may be smooth or rough or have teeth formed thereon in another aspect the gripping element 205 may include a retracting mechanism to control movement of the engagement members 206 in one embodiment an axial bore 260 is formed adjacent the interior surface of the gripping element 205 an actuating rod 265 is disposed in the bore 260 and through a recess 267 of the engagement members 206 the actuating rod 265 includes one or more supports 270 having an outer diameter larger than the recess 267 of the engagement members 206 a support 270 is positioned on the actuating rod 265 at a level below each engagement member 206 such that the engagement members 206 rest on their respective support 270 a biasing member 275 coupled to the actuating rod 265 is disposed at an upper end of.