GB2295432A - Screw head and screwdriver drive formations - Google Patents

Abstract

The drive recess in the head of a screw and the screwdriver tip for engaging in the recess, comprise two diametrical quadrants joined bv a narrow central section. Different sizes of such screwdrivers can be used on the same screw head, and different designs of screwdriver can be used with the same screw head. The recess and the tip may be flat, or may have a countersunk centre. <IMAGE>

Description

SCREW HEAD AND SCREWDRIVER HEAD This Invention relates to a screw head and screwdriver head.

Screws and Screwdrivers are in common everyday use throughout the world and have been used for many years for fastening one object to another.

However problems can often occur in the final stages of tightening and the early stages of un-tightening of screws.

This is often due to innacurate fit of the screwdriver sometimes causing it to slip out of its ideal position.

This innacurate fit and slippage of the screwdriver can cause damage to the screw head making fitting and especially extraction difficult.

This present Invention seeks to minimise slippage by offering a precise fit of screw head and screwdriver head of the same shape and design.

This Invention also enables different sizes of screwdrivers of the same shape and design head to be used on the same screw head.

Another feature of the screw head design is that other styles of screwdriver design may also be used on the same screw head.

Fig.1. Shows two dimensional drawing of screw with head design and screwdriver head design.

Fig.2. Shows plan of screw head.

fig.2.10. Being countersunk centre of screw to accept cross/star type screwdriver more readilly.

fig.2.11. Being ninety degree angles.

Fig.3. Shows plan of screwdriver head.

fig.3.12. Being equal parallel dimensions dissecting the centre.

fig.3.13. Being rounded edges.

Fig.4. Shows plan of head with small screwdriver head of the same design fitted.

fig.4.14. Being plan of small screwdriver head.

Fig.5. Shows plan of head with larger screwdriver of the same design fitted.

fig.5.15. Being plan of larger screwdriver head.

Fig.6. Shows plan of maximum fit screwdriver of the same design fitted.

fig.6.16. Being plan of maximum fit screwdriver head.

Fig.7. Shows two dimensional drawing of screw head with maximum fit screwdriver head of the same design fitted.

fig.7.17. Being maximum fit screwdriver.

Fig.8. Shows two dimensional drawing of screw head with slot head type screwdriver fitted.

fig.8.18. Being slot head type screwdriver.

fig.8.19. Being direction arrow indicating as screw S tightened.

Fig.9. Shows the same as Fig.8. but showing screw being un-tightened.

fig.9.20. Being direction arrow indicating as screw is un-tightened.

Fig.10. Shows two dimensional drawing of screw head with cross/star type screwdriver head fitted.

Directional arrows are not used in this example as this type of screwdriver does not move on its axis between tightening and un-tightening modes.

fig.9.21 . Being cross/star type screwdriver.

Claims (7)

1. A screw head and screwdriver head being of the same shape and design.

2. A screw head and screwdriver head as described in CLAIM 1. being of equal parallel central dimensions dissecting the centre of the heads.

3. A screw head and screwdriver head as claimed in any preceeding claim consisting of two ninety degree angles.

4. A screw head and screwdriver head as claimed in any preceeding claim having a flat bottomed screw head and flat bottomed screwdriver head.

5. A screw head and screwdriver head as claimed in any preceeding claim to have rounded outer edges.

6. A screw head and screwdriver head as claimed in any preceeding claim having a countersunk centre.

7. A screw head and screwdriver head as claimed and described herein with reference to figures 1-3 in the accompanying drawings.