GB2389551A

GB2389551A - Screwdriver with holding feature for socket screws

Info

Publication number: GB2389551A
Application number: GB0213582A
Authority: GB
Inventors: Martin Philcox
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-06-13
Filing date: 2002-06-13
Publication date: 2003-12-17
Anticipated expiration: 2022-06-13
Also published as: GB2389551B; GB0213582D0

Abstract

A screwdriver having a provision for holding a fastener in place on its tip before the fastener is installed, during installation, and during removal or after it is removed. The screwdriver comprises a handle and a shaft 1,3 made of more than one member. The ends of the shaft members 2,4 can be urged relative to one another via camming means 7 in order to frictionally engage a screw.

Description

( Screwdriver with holding feature for socket head screws 1. This

invention relates to a screwdriver having a provision for holding a fastener in place on its tip before the fastener is installed or after it is removed, more particularly to a screw driver having a hexagonal tip for engaging a fastener having an hexagonally shaped socket, which may be of regular form or of the recently introduced stepped form, in its head and to such a screw driver configured for installing or removing fasteners installed in bone during surgical procedures. The screwdriver can be configured to permit the insertion of cannulated fasteners installed along guiding wires or pins 2. It is also essential that any screwdriver be sufficiently robust to permit the application of the torque force required to enable a fastener to be corrletely inserted or removed' without deforming the screw driver or damaging the fastener 3. In any surgical procedure involving the insertion or removal of a fastener it is desirable to be able to grip the head of the fastener throughout the insertion or removal process to avoid any risk of the fastener being dropped or falling into the wound.

4. It is desirable for the surgeon performing the procedure, and /or for the nurses assisting, to be able to apply and release the force holding the fastener onto the screwdriver using only one hand.

Description of the several views of the drawings

FIG. 1 is a fragmentary side elevation of a screwdriver built in accordance with a first version of the present invention FIG. 2 is a fragmentary top elevation of a screwdriver built in accordance with a first version of the present invention FIG. 3 is a fragmentary isometric view of a screw driver built in accordance with a first version of the present invention showing the use of longitudinal grooves in the meeting faces of the shaft and the moving member to accommodate guiding wires used with cannulated fasteners.

FIG. 4 is a fragmentary top elevation of a screwdriver built in accordance with a second version of the proposed invention FIG. 5 is a fragmentary side elevation of a screwdriver built in accordance with a second version of the proposed invention

Detailed description of the invendon.

As shown in FIGS. 1 3 the screw driver comprises a main shaft 1 driven by a handle I (which is not shown) terminating in a hexagonal tip 2. Approximately half' of the distal portion of the shaft is cut away to forth an elongated shelf tennuating in the remaining half of the hexagonal tip A separate member 3 (the locking member) is configured to fit onto that shelf. The locking member is configured at its distal end to substantially form the other half of a hexagon tip 4. Both the shaft and the locking member may be grooved I longitudinally on their inner surfaces to permit the entry of guiding wires or pins used I with cannulated fasteners. The locking member is lightly radiused on its timer surface in a longitudinal plane towards its distal end and pivoted about a pin 5, which may be threaded, or plain, and which may be drilled to permit the passage of wires or pins used with correlated fasteners. In the first version an upper retaining pin 6, which may be plain or threaded or a combination of both is fitted through the free end of the locking member into the shaft to prevent the locking member being displaced by the application of the caroming lever. En the first version of this invention a camming lever 7 is fitted which rotates about a pivot 8, which may be threaded or plain or a combination of both, fitted into the shaft. A spring 9 may be fitted at sotne convenient position between the shaft and the locking member to exert a force tending to separate the locking member from the shaft, to facilitate insertion of the screwdriver into the socket head of the fastener and its removal from the fastener when required.

In operation the tips of the screwdriver 2 and 4 are inserted into the socket formed in the fastener head and the free end of the locking member 3 is forced down by rotation of the caroming lever 7. The locking member 3 rotates around the pivot 5 conforming to the radius formed on its underface and the two semi-hexagonal tips 2 and 4 are thus forced apart, exerting an outward clamping force against the internal sides of the socket head of the fastener and thereby holding it onto the screwdriver FIGS. 4-5 show a second version of the invention in which the operating force is applied i to the locking member 3 by a sliding sleeve 10 being forced towards the distal end of the screwdriver. In operation the screwdriver is inserted into the socket formed in the fastener head and the free end of the locking member 3 is forced down by the action of the sliding sleeve 10 which impinges upon the free end of the locking member and forces it drown towards the shaft. The locking member rotates around the the pivot 5 corforming to the radius formed on its underface and the two hexagonal halves of the tip 2 and 4 are thus forced apart, exerting an outward clamping force against the internal sides of the socket head of the fastener and thereby holding it onto the screwdriver. In this version of tile invention the upper locking member retu:ung pin 6 fitted in the first version may be omitted if desired.

Claims

as CLAIMS

1. A screwdriver for selectively griping screws having openings therein, the openings having side walls, comprising: a handle means a blade means connected to said handle means; said blade means connected to said handle means; each of the said blade members having a tip means and a contact surface so formed as to engage its portion of the screw opemng; each of said respective tip means being movable in a predetermined direction relative to the other one of said tip means; a camming means for urging each of said tip means relative to another in each said respective predetermined direction about a pivot, which direction is generally at right angles to said formed contact surface; whereby the said tip means are urged into frictional engagement with the sidewalls of the opening in the screw solely by the said camming means.

2. A screwdriver as claimed in claim 1, wherein said blade members are elongated members which are adapted to exert a compressive force within the said screw openings.

3. A screwdriver as claim in claim 1, wherein said camming means includes a rotating lever which urges the said blade members to pivot about the said pivot and cause the said tip means to apply a compressive force withm the said screw openings

4. A screwdriver as claimed in claim 1, wherein said camming means includes an axially moveable sleeve which urges the said blade members to pivot about the said pivot and cause the said tip means to apply a compressive force within the said screw openings 3.

5. A screwdriver as claimed in claim 1, wherein the upper of the said blade members has an inclined surface decreasing in height with axial distance from said pivot, wherein said rotating lever or said axially moving sleeve being in engagement with the end of said upper blade exerts a camming force upon said blade member.

6. A screwdriver as claimed in claim 1, wherein each of said tip means includes a generally trapezoidal portion in cross section adapted for insertion into a screw having a hexagonal opening.

7. A screwdriver as claimed in claim 1, wherein the inner surfaces of said blade members may be axially grooved to permit insertion of screws which are cannulated and which are inserted along a guiding wire, said guiding wire passing within the passage created by said grooves.

8. A screwdriver as claimed In claim 1, wherein said pivot is pierced to permit the passage of a guiding wire employed in conjunction with said cannulated screws.