Other

Hollingsworth (u.k.) Ltd.

Peter J Dickinson

Alan Parker

Douglas O Clough

William M Farnhill

Peter J Barratt

This invention relates to a screen printing stencil composition which comprises (a) a stabilized aqueous dispersion of a water insoluble addition copolymer having units of formulas: A and B where A is preferably a polyvinyl acetate group and B is preferably a polyvinyl n-methylol acrylamide group and B comprises about 3% by weight of the copolymer; (b) a water soluble colloid; and (c) a photosensitizer: The composition is useful in the formation of a screen printing stencil, the composition having both a long stable profile and forming a durable stencil; the composition on exposure through a photographic positive can be developed with water and cross-linked with acid.

Stabilized photosensitive screen printing dispersion composition with

Slubs are removed from an open-end spinning chamber by the application of suction to a debris-extraction duct by a valve opened to a suction line as the chamber is opened to a suction line as the chamber is opened for cleaning.

Friction spinning apparatus with slub clearing means

The mask sleeve within the perforated roller of each spinning unit of a multi-position friction spinning apparatus is adjustable to move the suction slot of that roller between extreme positions in which an edge of the slot crosses from one side of the friction spinning nip to the other. Adjustment at each spinning unit is effected independently of the various other units of the machine by means of a rotary adjuster engaging a bifurcated end of a carrier which is itself adjustably fastened (by way of a clamp bolt) with respect to the masking cylinder. The adjuster and the carrier are outside the machine and allow adjustment of the positioning of the slot deep within the spinning unit for fine tuning purposes.

Friction spinning apparatus

Friction spinning apparatus for producing a composite yarn has a groove or recess formed in at least one of the friction spinning rollers, to receive a strand guide tube which can then guide a core strand directly to the yarn formation line substantially at the nip between the rollers.

Apparatus for forming a composite yarn by friction spinning

A composite yarn comprising a component of staple fibres and a component formed by a continuous strand is spun on a friction spinning apparatus. Staple fibres are fed to a twisting zone where the fibres are twisted to form a staple strand with one end open. The continuous strand is joined with the staple strand at a position within a portion of the staple strand which is in the process of being twisted, and such that fibres are joined with the staple strand both upstream and downstream of the joining position and some fibres join with the staple strand on both sides of the joining position. In this way a yarn is formed with some fibres forming an inner core twisted with the continuous strand, with some fibres forming on outer sheath around the core and continuous strand and some fibres having part of their length in the core and part in the sheath.

Composite yarn

The yarn formation area of a friction spinning apparatus, in which the rotating friction rollers and the feed duct lie closely adjacent, is quickly and simply cleaned of remaining fibres at a yarn break and protection is provided against damage caused by excess fibres entering the area. One of the rollers, which is imperforate, is mounted for pivotal movement away from the area and at a break suction through the other roller is temporarily closed off from one end of the area toward the opposite end to eject the remaining fibres. Return movement of the roller is guided to ensure proper return to the operating position.

Friction spinning apparatus and method for cleaning

Spinning is started on a friction spinning apparatus by drawing the end of yarn back to a position adjacent the surface but in such a condition that it is free from the influence of the suction through the surface. This is done by closing off the suction while the end is in the position so that the yarn is drawn by an additional suction source into an adjacent position. The yarn end is drawn from one end of the surface to lie along the surface by gradually closing off the suction from that end toward the opposite end. Subsequently the suction is reopened to bring the yarn end under its influence to draw the end onto the surface so the fibre feed and take-up can be restarted.

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Rossendale, United Kingdom

Peter J Dickinson