GB936733A - Improvements in or relating to textile drafting mechanism - Google Patents

Abstract

936,733. Drafting mechanisms. SKF. KUGELLAGERFABRIKEN G.m.b.H. Dec. 4, 1959 [Dec. 6, 1958; Dec. 10, 1958], No. 41335/59. Class 120 (2). In drafting mechanism having a pivoted arm carrying single or twin top-rolls, at least one top roll or one pair of twin top rolls is held against its associated bottom roll by one or more magnets embodied in or carried by the top roll or rolls. In a twin roll construction, Fig. 2, the rolls comprise covers 3<SP>1</SP>, a permanent magnet 3 and polepieces 5 and are carried by a bracket 7 adjustably bolted to the carrier arm 2 which extends downwardly in grooves in the bracket. The bracket has half-rings 8 carrying the trunnions of rollers 9 running on integral or other collars 10 which may be adjustable, or grooves in the neck of the rolls. In another arrangement, the rollers and bracket are dispensed with and the carrier arm adjustably carries jaw-shaped members embracing one half of a circumferential groove in the roll. In another twin roll construction, a carrier arm for a series of twin rolls is detachably held in a supporting-bar on the machine frame by a spring-detent and positioning rings, and the top rolls are held by guide arms 19, Fig. 13, which may be adjustable in length, pivotally carried by brackets adjustably secured in the carrier arm. Each guide arm 19 may rotatably or fixedly carry the roll journal: in the former case the arm may provide a half-bushing 19<SP>1</SP> in which the roll-journal is supported in two spaced rows of balls 16<SP>1</SP> running in a sleeve 17<SP>1</SP> and grooves in the journal or a sleeve thereon; in the latter case, the balls are pivoted between the journal and sleeves inside the rolls, the magnets being arranged as in Fig. 7 (see below). In Fig. 15, twin top rolls 14 are carried by guide arm 24 at the necks 14<SP>1</SP> and are weighted partly by internal magnets and partly by springs. When it is desired to relieve the pressure on the rolls to protect the roll covers, but at the same time to hold the sliver sufficiently to prevent the twist running back into the drafting field, the arm is partly raised by a lever 23, the arms 24 descend as far as retaining stops allow, and the rolls, under the pull of the magnets, descend to the bottom of the guides where they are held by detents 25 so that the sliver is still gripped; the retaining force of the detent is greater than the pull of the corresponding magnet so that the carrier arm can be completely raised if desired. In Figs. 6 and 7 sets of single rolls 14 mounted cantilever-wise are provided for each drafting station: in Fig. 6 the rolls have magnets M and polepieces 5, 5<SP>1</SP> and are adjustably carried in a carrier arm 13, journals 14<SP>1</SP> extending through slots in the arm into bearing housings 15 where balls 16 run in tracks in the housing, or in the arm 13, or on the journal. In Fig. 7, the journal is rigidly secured to the arm, the balls 16<SP>11</SP> run in tracks in the journal or in a sleeve secured thereto and in a sleeve 17 on the roll, and the magnets M<SP>1</SP> are provided at each end of the roll and each comprise discs of opposite polarity separated by non-magnetic material. In all forms, the rollers may be retained in their holders by safety catches, the rollers and their tracks may be of non-magnetic materials, and screened from the magnets by discs of soft iron &c.