The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 19, 1999
Filed:
Feb. 10, 1998
John D Ross, Jr, Ovilla, TX (US);
Mikhail L Samchukov, Coppell, TX (US);
John G Birch, Dallas, TX (US);
Texas Scottish Rite Hospital for Children, Dallas, TX (US);
Abstract
A distraction apparatus for an external fixation device used to rigidly immobilize bone fragments during bone lengthening and angular deformity correction includes distractor mechanisms and pivotable spacers for connecting frame members of an external fixator, and wire and half pin fasteners. The interconnected distractor mechanisms, pivotable spacers and frame members form a rigid structure with rigidity which is maintained during adjustment of the distraction. For linear distraction, the distraction mechanism is a single screw assembly with a single-threaded rod and dual plastic nuts disposed either side of a metallic adjustment surface. After tightening down, the nuts may be synchronously co-rotated, advantageously using a tool such as a double wrench engaging on aligned faces of the nuts. This synchronous co-rotation causes linear displacement along the threaded rod, thereby enabling distraction. Further, the metal-to-plastic inter-face between the nuts and the adjustment surface facilitates this synchronous co-rotating without causing loosening of the nuts, thereby minimizing the introduction of play in the mechanism during distraction.