Patent Application
20060161262
(a) Field of the Invention
The present invention relates to a thighbone shaft, and particularly to a thighbone shaft which has a pole and a bolt mounted on an inclined threaded hole in the pole and which is adapted for artificial joint or the similar.
(b) Description of the Prior Art
As disclosed in Taiwan Patent No. 89219012, a conventional artificial joint has a thighbone shaft, which is made of titanium alloy and plants into a user's thighbone. The thighbone shaft comprises:
a front portion, which shrinks gradually and is covered by an adhesion layer and a coating layer, a neck portion connecting with an end of the front portion, a sleeve portion connecting with the neck portion;
a middle portion connecting with an end of the front portion and opposite to the neck portion, and forming a rough surface;
a tail portion connecting with an end of the middle portion, and forming a polishing surface, symmetric grooves being defined in the polishing surface.
In this design, stress force put on the tail portion is reduced, thereby avoiding pain feel of thighbone side, achieving optimal planting effect, and decreasing occurrence of strain barrier. However, this design damages large area of thighbone and produces large area of wound. Moreover, the thighbone shaft is relatively large. The overall thighbone shaft has to be replaced when the thighbone shaft is worn out after long period of use. Such a thighbone shaft cannot meet users' need.
Accordingly, an object of the present invention is to provide a thighbone shaft, which has a pole, a head arranged on a front portion of the pole, and a bolt mounted on an inclined threaded hole in the pole, whereby the stress force portion of the thighbone, namely thighbone neck, remains. A thighbone neck acts as a planting point, damaging small area of the thighbone. Only thighbone and acetabulum which have worn-out cartilage need to be replaced, and therefore wound area is relatively small, size of planted thighbone shaft is reduced, stress force decreases, and convenience and utility increases.
Another object of the present invention is to provide a thighbone shaft, wherein only a head thereof need to be replaced rather than the overall thighbone shaft after long term of use, thereby reducing cost and making operation easier.
A further object of the present invention is to provide a thighbone shaft, which has tooth portions on opposite sides of the pole thereof for increasing contact area of planting and forming lock structure, thereby promoting planting fixedness.
A thighbone shaft of the present invention comprises a pole and a bolt. The pole defines an inclined threaded hole therein. Tooth portions are respectively formed at opposite sides of the pole. A head is arranged on a front portion of the pole. A sleeve is provided on a front portion of the head. The bolt forms a threaded portion for fitting in the inclined threaded hole thereby engaging the bolt with the pole. Thus, the thighbone shaft is assembled easily, simultaneously reducing planting area and replacement cost, decreasing stress force, and promoting planting fixedness.
With reference to FIGS. 1 to 4, a thighbone shaft of a first embodiment of the present invention comprises a pole 10, a head 20 mounted on the pole 10, and a separate bolt 30. The pole 10 defines an inclined threaded hole 11 therein. Tooth portions 12 are respectively formed at opposite sides of the pole 10. A through hole 13 is longitudinally defined through a center of the pole 10. A step 131 is formed in the through hole 13.
The head 20 has a rear end fixed on the through hole 13, and a front end beyond the pole 10. The head 20 defines a positioning hole 22 in the rear end thereof for engaging firmly with a fixing element 40. The fixing element 40 forms a shoulder 41 for abutting with the step 131 in the through hole 13. A sleeve 21 is provided on the front end of the head 20. The head 20 forms a projection 23 at rear of the sleeve 21 for abutting a front surface of the pole 10.
The bolt 30 forms a threaded portion 31 for fitting in the inclined threaded hole 11 of the pole 10, thereby engaging the bolt 30 with the pole 10.
Further referring to
The tooth portions 12 on the pole 10 increase contact area of planting and forms lock structure, promoting planting fixedness and achieving optimal planting effect.
Referring to
It is understood that the invention may be embodied in other forms without departing from the spirit thereof. Thus, the present examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.
