Apparatus for driving a bone fixation pin

Patent metadata

Field	Value
Publication number	US-10849671-B2
Application number	US-201916439185-A
Country	US
Kind code	B2
Filing date	Jun 12, 2019
Priority date	Mar 1, 2019
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

A bone fixation pin is inserted into a bone with an apparatus comprising a housing having a proximal portion and a distal portion, the distal portion having an inner surface and an opening configured to receive the bone fixation pin; a drive shaft having a proximal end configured to engage a handle and a distal end; and a body having an axis and a peripheral edge. The body comprises a bore along the axis, the bore being configured to slidably engage the distal end of the drive shaft; and a plurality of evenly spaced slots in the peripheral edge of the body. A plurality of chuck arms move radially along the evenly spaced slots in the peripheral edge of the body, each chuck arm having an inner surface and an outer surface, with each chuck arm being biased toward the axis of the body by a first biasing force. The outer surface of each chuck arm slidably engages the inner surface of the housing. The distal end of the drive shaft and the body are within the proximal portion of the housing, with the body being biased toward the distal end of the housing by a second biasing force. Each chuck arm has an engaging surface configured to engage a head of the bone fixation pin, where pressure applied to the engaging surface drives the chuck arms in a radial direction against the first biasing force, and simultaneously drives the body carrying the chuck arms axially against the second biasing force.

First claim

What is claimed is:

1. An apparatus for inserting a bone fixation pin having a head and a cylindrical body having a body diameter, said apparatus comprising:
a housing having a proximal portion and a distal portion, the distal portion having a stepped inner surface and an opening configured to receive the bone fixation pin;
a drive shaft having a proximal end configured to engage a handle and a distal end;
a body having an axis and a peripheral edge, said body comprising:
a bore along the axis, said bore being configured to slidably engage the distal end of the drive shaft; and
a plurality of spaced slots in the peripheral edge of the body; and

wherein the distal end of the drive shaft and the body are within the proximal portion of the housing, the body being biased toward the distal end of the housing by a first biasing force; and
a plurality of chuck arms having an inner surface and an outer surface, each chuck arm being configured to move radially along one of the spaced slots in the peripheral edge of the body, wherein the inner surface of each chuck arm is configured to engage the bone fixation pin,
each chuck arm being biased toward the axis of the body by a second biasing force so that the lower tip of each chuck arm slidably engages a first step on the stepped inner surface of the housing.

2. The apparatus of claim 1 , wherein the apparatus is configured to insert a bone fixation pin having a rounded or frustoconical head and a body having:
the cylindrical portion distal to the rounded or frustoconical head, and
a body portion having a plurality of planar surfaces proximal to the rounded or frustoconical head;
wherein the inner surface of each chuck arm has:
a slanted lower portion configured to engage the rounded or frustoconical head of the bone fixation pin; and
a planar upper portion configured to engage one of the planar surfaces of the bone fixation pin.

3. The apparatus of claim 2 , wherein the distal end of the drive shaft has a conical or frustoconical opening configured to receive the rounded or frustoconical head of the bone fixation pin.

4. The apparatus of claim 3 , wherein the apparatus is configured to receive a bone fixation pin through the opening in the housing until the head of the pin engages the conical or frustoconical opening in the distal end of the drive shaft;
wherein contact between the conical or frustoconical head of the bone fixation pin and the slanted lower portions of the chuck arms pushes the chuck arms toward the proximal end of the housing against the first biasing force; and
wherein the lower tip of each chuck arm is configured to disengage from the first step on the stepped inner surface of the housing and engage a second step on the stepped inner surface as the chuck arms move toward the proximal end of the housing;
wherein planar upper portions of the chuck arms are configured to engage the planar surfaces of the bone fixation pin when the lower tip of each chuck arm engages the second step on the stepped inner surface.

5. The apparatus of claim 4 , wherein the lower tip of each chuck arm is configured to:
disengage from the first step on the stepped inner surface of the housing: and
engage the second step on the stepped inner surface;
wherein the chuck arms move radially on the body against the second biasing force after disengaging from the first step.

6. The apparatus of claim 4 , wherein the stepped inner surface of the housing comprises a second step and a third step, said second step and said third step being configured to be sequentially engaged by the lower tip of each chuck arm as the chuck arms move toward the proximal end of the housing;
wherein the chuck arms are configured to engage the cylindrical body of a bone fixation pin having a first body diameter when the lower tip of each chuck arm engages the second step on the stepped inner surface; and
wherein the chuck arms are configured to engage the cylindrical body of a bone fixation pin having a second body diameter when the lower tip of each chuck arm engages the third step on the stepped inner surface.

7. The apparatus of claim 1 , wherein the body is biased toward the distal end of the housing by a first spring configured to apply the first biasing force; and
each chuck arm is biased toward the axis of the body by a second spring configured to apply the second biasing force.

8. The apparatus of claim 7 , wherein the body is biased toward the distal end of the housing by the first spring, the first spring being a compression spring, the compression spring having a first end mounted to the drive shaft and a second end pressing against the body.

9. The apparatus of claim 7 , wherein each chuck arm has an outer surface with a spring mounting surface thereon; and
the chuck arms are biased toward the axis of the body by the second spring, the second spring being a circular garter spring seated on the spring mounting surfaces of the chuck arms.

10. The apparatus of claim 1 , wherein the body is biased toward the distal end of the housing by a first spring configured to apply the first biasing force; and
each chuck arm is biased toward the axis of the body by a leaf spring mounted on an inner surface of the proximal portion of the housing, the leaf spring being configured to apply the second biasing force.

11. The apparatus of claim 1 , wherein the body is biased toward the distal end of the housing by a first spring configured to apply the first biasing force; and
the chuck arms are biased toward the axis of the body by an elastic band engaging an outer surface of each chuck arm, the elastic band being configured to apply the second biasing force.

Assignees

• Depuy Synthes Products Inc

Inventors

• Loftus-Vergari Jeffrey
• Krevitski Steven
• Smith Kory
• Darrow Jeffrey

Classifications

• Y10S279/906

  Self grasping socket · CPC title

• B23B31/1215

  Details of the jaws · CPC title

• A61B17/848

  Kirschner wires, i.e. thin, long nails · CPC title

• A61B17/86

  Pins or screws {or threaded wires; nuts therefor (A61B17/72 take precedence)} · CPC title

• A61B17/8875 Primary

  Screwdrivers, spanners or wrenches · CPC title