GB229716A - Improvements in or connected with warp tensioning devices for looms - Google Patents

Abstract

229,716. Brigg, T. H. Aug. 27, 1923. Warp beams; letting- off warps; warps, tensioning and guiding.- Feeler or indicating mechanism acted upon by the warp at a point not affected by the varying diameter of the warp on the beam, and operated by the warp only at a determined portion of each shedding cycle controls doubleacting intermeshing mechanism to vary tne braking effect on the warp beam or to vary the speed of let-off where a positive let-off motion is used. The feeler mechanism may comprise a lever 40, Fig. 7, controlled by springs 45 and connected to a hooked rod 43 passing beneath a rod 44 acted upon by the warp at a point just behind the shed. The lever 40 moves as the warp tension varies and actuates a rod 42, which controls intermeshing mechanism A. To ensure the feeler mechanism being operated intermittently only, it is locked against operation at the moment of beating-up by a movable clamping member 47 co-operating with a fixed block 46 to clamp the rod 42. The jacks of the shedding motion may be utilized to furnish this intermediate warp tension feeler mechanism. The intermediary mechanism may comprise two free wheel sprockets 7, 8, Fig. 2, mounted on a shaft 1 and adapted to be engaged by one or the other or neither of two pawls or actuating-members 9<1>, 10<1> on connected oscillating levers 9, 10, forming an enclosing, dirt-proof casing for the sprockets. The levers 9, 10 have an extension 11 whereby they are oscillated from some part of the loom. When the warp tension varies from a certain predetermined amount, a clutch fork 12 controlled by the feeler mechanism moves the levers 9, 10 axially so that one of the two pawls 9, 10 engages with its respective sprockets and the shaft 1 is turned in one direction or the other. In a modification, the intermediary mechanism comprises two ratchet-wheels with oppositely-directed teeth, two driving-pawls and a shield. The shaft 1 may operate by worm and rack gearing a weighted lever 14, Fig. 3, so as to alter the position of a bowl 15 on a lever 16<1>, 16<2> pivoted at 17 and carrying guide-bowls 23, 26 for a rope 18 passing round bowls 19, 19<1> carried by the end pieces of ropes, clips or chains 20, 20' passed round the warp beam ruffle. The shaft 1 may be used to vary the position of the weight on a let-off motion of the worm and worm wheel or positive type so as to compensate for the varying mechanical leverage of the pull of the warp as the warp beam empties. The mechanism may also be used otherwise in let-off motions to vary the rate of let-off. In addition, it may control the position of the warp beam, in case no back rail is used, the beam shaft 33, Fig. 5, being carried by arms 34 on a shaft furnished with a toothed quadrant 36 driven by a worm 13<a> fast on a shaft driven from the intermediary mechanism, whereby the angle of the line at which the warp passes to the healds may be maintained constant as the beam empties.