Itw Limited

Illinois Tool Works Inc.

Utw Limited

Robert H Day

George D Hewison

A method of making a screw threaded fastener (1, 10) for fixing cladding to a building includes the steps of applying a mastic covering (5, 15) to a screw threaded portion (4, 13) of the fastener, and applying a non-sticky protective coating (6, 16) to the outside of the mastic covering (5, 15) so as to prevent the fasteners (1, 10) from sticking together during handling and packaging of the same. Preferably the protective coating (6, 16) is as coating of a waxy substance and is applied to the outside of the mastic covering (5, 15) by means of a dipping or spraying process or operation. The fasteners are then easy to use and form a water-tight, moisture and vapor-proof seal with respect to their supports or substrates. The waxy coating (16) may also be applied to the drill point (12) so as to act as a lubricant during driving of the fastener.

Coating screws wtih sealant

Coating of screws

It is known for colored plastics caps to be pushed by a customer onto heads of metal screws, after the screws have been secured to sheets of colored cladding or roofing. It is also known for the caps to be molded around the screw heads by a manufacturer. In the present invention, a screw/cap assembly is formed by bonding an initially separate cap onto the head of a screw by means of an adhesive, such as an epoxy resin sufficiently strong to allow the screw to be driven while the cap is in place. The intention is that the manufacturer would maintain stocks of the caps and stocks of the screws of different types, and only secure predetermined caps onto the heads of predetermined screws in response to specific orders from customers.

Screw/cap assemblies and their manufacture

A cup comprising a bottom and sidewall, the cup being shaped so that it can be assembled into a stack between other identical cups, in upright attitude, into a condition in which:

Cups capable of nesting

A thin-walled cup including wall portions having internal and external surfaces so shaped that, when the cup is nested with an identical cup in an upright attitude, the said external surfaces of the upper cup cooperate with the said internal surfaces of the lower cup, so as to resist separation of the cups, provide a seal between the cups, and provide for cushioned relative movement of the cups towards each other, with a limit to such movement.

Thin-walled cups capable of nesting

Apparatus and method for thermoforming two or more plastics sheets simultaneously, to form in one operation a double-walled cup, or a composite walled cup, or a plurality of single-walled cups. The sheets are moved and heated simultaneously, the portion not being thermoformed being kept apart, permitting economy of scrap remelting. The thermoformed portions can be kept apart by pressure between the sheets, which can serve to hotform the sheets against respective mould surfaces, or air pressure can bond the sheets together. Existing machines need substantially only an additional clamping plate, heater, and compressed air passing through a radial port in a clamping plate, to incorporate the invention.

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Berkshire, United Kingdom

Robert H Day