Patent ID: 8758343

Claim:
An apparatus for engaging first and second bone fixation elements in a bone fixation frame, comprising: a first clamp structure, having at least two bores for engaging at least two first bone fixation elements having a first spherically contoured bearing surface; a second clamp structure, having at least one bore for engaging at least one second bone fixation element, having a second spherically contoured bearing surface seated in sliding contact with the first bearing surface; a connector bolt having a head engaging the second clamp structure and a screw-threaded stem extending to the first clamp structure; a tightening device in screw-threaded engagement with the stem of the connector bolt; and a spring compressed between the first clamp structure and the tightening device, whereby the tightening device can apply a spring force to the connector bolt to tighten the contact of the bearing surfaces by moving the bearing surfaces toward one another.