Balance compensated screw thread and method for making the same

Abstract

A method for making a balance compensated orthopedic screw and the end product of the method is disclosed. In one embodiment, the bar stock is selectively rotated in predetermined rotation degrees, and in opposite directions while the thread is being cut into the bar stock. In another implementation, the thread cutting blades can be selectively rotated around a stationary bar stock in a predetermined direction of rotation while cutting the thread and changing the direction of rotation of the cutting blades to impart cutting in a different direction on the bar stock.

Description

This invention discloses a method for manufacturing balanced compensating straightening threads and the final product of the method. In one embodiment, while the thread is being cut into a bar, the bar selectively rotates in opposite directions at a predetermined rotation angle. In another implementation, a thread-cutting blade can selectively rotate about a fixed bar along a predetermined rotation direction while cutting the thread, and the rotation direction of the cutting blade can be changed to cut along different directions on the bar. Abstract

Claims

Attorney Docket: 0707-0006-0WO CLAIMS 1. A method for manufacturing an orthopedic screw comprising: rotating a bar stock in a machine for a first predetermined amount of rotation in a first direction; cutting (86) a thread into the bar stock using a blade for the first predetermined amount of rotation; changing the first rotation direction of the bar stock to a second rotation direction opposite the first rotation direction for a second predetermined amount of rotation; and cutting (88) the thread into the bar stock using the blade for the second predetermined amount of rotation.

2. The method according to claim 1, wherein the first predetermined amount of rotation is 45 degrees.

3. The method according to claim 1, wherein the second predetermined amount of rotation is 45 degrees.

4. The method according to claim 1, wherein the first predetermined amount of rotation is 90 degrees.

5. The method according to claim 1, wherein the second predetermined amount of rotation is 90 degrees.Attorney Docket: 0707-0006-0WO 6. The method according to claim 1, wherein the first predetermined amount of rotation is in a range of 90-180 degrees.

7. The method according to claim 1, wherein the second predetermined amount of rotation is in a range of 90-180 degrees.

8. An orthopedic screw manufactured in accordance with the method of claim 1.

9. A method for manufacturing an orthopedic screw comprising: rotating a bar stock in a machine for a first predetermined amount of rotation in a first rotation direction; cutting (86) a thread into the bar stock using a blade rotating opposite the first rotation direction for the first predetermined amount of rotation; changing the first rotation direction of the bar stock to a second rotation direction opposite the first rotation direction for a second predetermined amount of rotation; and cutting (88) the thread into the bar stock using the blade rotating opposite the second rotation direction for the second predetermined amount of rotation.

10. A method for manufacturing an orthopedic screw comprising: placing a bar stock in a machine; cutting (86) a thread into the bar stock using a first blade rotating in the first direction; andAttorney Docket: 0707-0006-0WO cutting (88) the thread into the bar stock using a second blade positioned so as to not interfere with the cutting by the first blade, the second blade rotating in a second direction opposite the first direction.

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