AU2003100544A4

AU2003100544A4 - Self-drilling screws

Info

Publication number: AU2003100544A4
Application number: AU2003100544A
Authority: AU
Inventors: David Roberts
Original assignee: ITW AFC Pty Ltd
Current assignee: ITW AFC Pty Ltd
Priority date: 2002-07-18
Filing date: 2003-07-08
Publication date: 2003-08-14
Anticipated expiration: 2011-07-08

Description

P:OPER\RSH\ 1226(450I)-spcdo 4)iAP?3A -1- SELF-DRILLING SCREWS The present invention relates to self-drilling screws for use in building and construction.

Self-drilling screws for fixing to steel or other metal are well known and would typically be used for such applications as securing sheets of roofing or cladding material to metal battens or purlins and other applications where it is required to secure a component to a metal substrate. The screw will typically comprise a fluted drilling end portion with a drilling tip at its outer end. A self-tapping thread extends along the shank of the screw from the inner end portion of the drilling portion towards the head; depending on the particular application for which the screw is designed, the thread may terminate short of the head.

In one common form, the head is hexagonal form to fit into a standard Hex socket of a power-operated driver drill.

Although self-drilling screws of the type described above are produced in a range of different sizes, many construction projects involve the use of significant numbers of selfdrilling screws of both 12 and 14 gauge. The relevant Australian Standard proposes different hexagonal head sizes for 12 gauge and 14 gauge self-drilling screws of this type, with the result that a tradesperson erecting a structure requiring the use of both 12 and 14 gauge screws will be required frequently to change driving sockets. This leads to reduced efficiency.

According to the present invention there is provided in combination a plurality of selfdrilling screws of 14 gauge and 12 gauge, each screw comprising a drilling portion, a selftapping thread, and a head having a hexagonal driving portion, wherein the hexagonal driving portions of the 12 gauge screws and 14 gauge screws are sized for driving cooperation with the same driving socket.

Further according to the present invention there is provided a self-drilling screw P:\OPER\RSH\122,645-spe.doc4)AI7/)3 -2comprising a drilling portion, a self-tapping thread and a head having a hexagonal driving portion, wherein the hexagonal driving portion has a width across flats of between substantially 7.78mm and 7.92mm, the screw being a 14 gauge screw.

Still further according to the present invention there is provided a method of erecting structure involving the use of a multiplicity of 12 gauge and 14 gauge self-drilling screws as defined above, wherein the screws are driven into metal substrate using throughout a driving socket of the same size.

An embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which:- Figure 1 is a side view of a 14 gauge self-drilling screw in accordance with the invention; and Figure 2 is an end view showing the head of the screw.

There is shown in the accompanying drawings a 14 gauge self-drilling screw in accordance with the invention. Apart from the head, the screw is of substantially conventional construction comprising a fluted drilling portion 2 terminating in a drilling tip 4, and a selftapping thread 6 extending from the inner end of the drilling portion 2 towards the head 8.

The head 8 itself consists of a hexagonal driving portion 10 extending outwardly from an integral washer 11.

For a standard 14 gauge self-drilling screw of the form illustrated, the width W, across the flats of the hexagonal driving portion 10 should be between 9.32mm and 9.52mm with the minimum width W 2 between opposite corners being 10.39mm. In contrast, in the selfdrilling screw in accordance with the invention, the hexagonal driving portion 10 is of somewhat reduced dimension such that the width W, across the flats is between substantially 7.78mm and 7.92mm with the minimum width W 2 between opposed corners being substantially 8.64mm. These dimensions for the hexagonal driving portion 10 of the 14 gauge screw in accordance with the invention correspond to the dimensions proposed in

A

P:\OPER\RSH\1226I45-spdpoc41l)7A)3 -3the relevant Australian Standard for the hexagonal driving portion of a standard 12 gauge self-drilling screw of this type. As a result of this change in head dimensions, 12 gauge and 14 gauge screws can be driven using the same Hex driving socket and for a construction project involving the use of substantial numbers of these two sizes of screw, improvements in efficiency should arise. An example of a construction project involving the use of substantial numbers of 12 and 14 gauge self-drilling screws is the assembly of prefabricated buildings comprising a metal framework, metal cladding, and metal roofing.

In a project such as this the 14 gauge screws are principally only used for holding purlins and girts within the structure of the building to achieve the required shear strength in the joints; as such, these screws will only need to be of a single style and length. In contrast, the 12 gauge screws used in the construction will be chosen from "standard" screws currently available.

Although the screw in accordance with the invention diverges from the relevant Australian Standard in terms of the size of its hexagonal driving portion, the applicants have determined that this divergence will not compromise the performance of the screw.

The embodiment has been described by way of example only and modifications are possible within the scope of the invention.

Claims

1. In combination a plurality of self-drilling screws of 14 gauge and 12 gauge, each screw comprising a drilling portion, a self-tapping thread, and a head having a hexagonal driving portion, wherein the hexagonal driving portions of the 12 gauge screws and 14 gauge screws are sized for driving cooperation with the same driving socket.

2. A self-drilling screw comprising a drilling portion, a self-tapping thread and a head having a hexagonal driving portion, wherein the hexagonal driving portion has a width across flats of between substantially 7.78mm and 7.92mm, the screw being a 14 gauge screw.

3. A method of erecting structure involving the use of a multiplicity of 12 gauge and 14 gauge self-drilling screws as defined above, wherein the screws are driven into metal substrate using throughout a driving socket of the same size.

4. A 14 gauge screw substantially as hereinbefore described with reference to the drawings. DATED this 8 t h day of July 2003 ITW AFC Pty Ltd By DAVIES COLLISON CAVE Patent Attorneys for the applicant