GB1035638A - Balloon limiter for twisting frames, particularly double-twist twisting frames - Google Patents

Abstract

In Fig. 2 (not shown) a balloon limiter for a double twist device comprises a rigid outer wall 10 and a resilient inner wall 12 defining an enclosed volume 13 which can be filled with a gas or liquid at an adjustable pressure. The pressure may be raised or lowered to change the shape of the inner wall. The inner wall 12 may be of rubber or a plastic foam and it preferably has ribs or scales on its inner surface; the wall may be of ferous material so that the fluid in volume 13 percolates therethrough to act as lubricant. Figs. 7 and 8, (not shown), the inner wall 12 is polygonal in horizontal cross section and tapers towards the bottom: each panel of the wall may bulge inwardly at its centre. Radial walls may be formed between the inner and outer walls to form separate cells. In a further form the inner polygonal surface of the limiter is defined by separate cells positioned edge to edge. Instead of maintaining a constant pressure in the fluid, between the walls this pressure may be pulsated so that the walls vibrate and contact between the balloon and the limiter is intermittent. In an alternative embodiment a cushion of e.g. foam or soft rubber is formed on the rigid outer wall and the inner wall coated with e.g.p.t.f.e or polychloro-trifluoroethylene together with e.g. polyvinyl chloride, polyamide, polyurethane, polyureas, melamines or formaldehyde resins. Fabrics, glass fibres or paper are preferably inserted as reinforcing elements. Blind holes and grooves may be formed in the outer side of the cushioning to increase its resilience.