IE44725B1 - A peripherally grooved firction roller for twisting fibres - Google Patents

Description

The present invention relates to a peripherally-grooved friction roller for twisting fibres, especially steel wires or braids and other linear textile structures used as reinforcing members in rubber or plastics material articles.

For twisting fibres - fibres in the present connection according to 5 the definition in accordance with DIN 60 900 in the widest sense are to be understood as substantially endless or limited in length linear flexible structures of all kinds and origin -, for imparting or cancelling a permanent twist or so-called false twist and for similar textile purposes, processing devices are known and frequently in use which have partly proved to be good.

A basic principle common to all these devices is the pressing of the paying out fibres against friction surfaces moved relative thereto, whereby the particular configuration and the drive of the friction surfaces, in combination with measures aiming at guidance and pressing of the fibres, produces at least in part, the desired effects. The demands on the necessary driving and control devices, however, make the known devices prone to wear and breakdown. In many cases, the control means provided are inadequate; deviations and fluctuations of the adjusted torsion values are often removable with difficulty or with considerable expenditure of time; erection of the relatively comprehensive devices or their accommodation on the processing machines under certain circumstances causes problems of space with the ensuing compulsion to undesired reorganisations in the operating cycle, and finally the economy of the overall plant is also impaired by the generally high purchase price. Further problems result from the varying property of the processed fibres: whilst, for example, yarns and twists made of natural fibre due to their slightly adhesive surface property present favourable conditions for fibre guidance without interference also over curved friction surfaces, steel wires which in comparison are smooth and rigid, and as used to an increasing extent for reinforcing plies in pneumatic tyres and heavy duty conveyor belts, are subjected to substantially more problematic starting conditions. For all these reasons, it has been a requirement in practice for a long time to provide a twisting device of simple structure and cheap design and breakdown free in use, which will operate safely and be reliable over long periods, which device may be incorporated in existing plant having a minimum of space requirement and with extensive control possibilities, which at the same time presenting the advantage of being universally applicable.

To close this gap, which hitherto has been regarded as a deficiency, is to be regarded as the object of the invention.

According to the invention there is provided an apparatus for twisting fibres, more especially steel wires or braids and other linear textile structures serving as reinforcing members in rubber or plastics material articles, comprising a friction roller mounted so as to be freely rotatable about its longitudinal axis and adjustable through an angle relative to a line between two fibre guide means located on either side of the friction roller, and having an outwardly flared peripheral groove, the flanks of which in variable diametrical regions form abutting surfaces for the fibre, in which the peripheral groove of the friction roller is provided with flanks which extend conically straight in the inner region of the groove, but in the outer region are adapted with a convex curvature merging into the axial direction of the friction roller.

The apparatus in accordance with the invention fulfils the expectations connected therewith in every respect. Its surprisingly simple structure, besides the necessary fibre guides known per se, consists substantially only of an undriven rotating friction roller, which makes it extremely robust and insensitive to breakdowns, and consequently the otherwise essential maintenance work may be completely dispensed with.

As possible repair measure still required after a long period of use, it suffices to replace the friction roller as the only movable part of the apparatus, which in view of the uncomplicated, simple structure may be effected simply and at speed. On the other hand, the extensive adjustability of the friction roller, which may be operated without constructional difficulties continuously in both directions over an angle region of 90°to 0°, relative to the delivery direction of the fibre in the guide distance, may be achieved with any required control, as well as the possibility of effecting optional correction operations and having a direct effect. With particular stress of this aspect, it may be favourable in accordance with a preferred feature of the invention to arrange at least one of the guides normal to the delivery direction of the fibre, so that additional effect may also be exerted in this manner within the guide distance and besides the twisting, for example, also a directional effect be exerted. The fibre passing in the form of a chord in a geometrical sense through the peripheral groove of the frictionally engaged friction roller fits snugly and is subjected to greater or lesser deformation axially against diameter regions of the groove flanks moved relatively at varying peripheral speeds, and both in the feed and the axially opposite outlet region receives aligned twisting impulses accumulative in their effect, the size and dimension of which results in dependence upon the tilt of the friction roller and therefore may be set optionally at between zero-corresponding to the pivotal axle angle of 90°, and a maximum value predetermined by the diameter of the friction roller.

The possible relatively strong pressure of the fibre against the flanks of the peripheralgroove, however, makes the apparatus also particularly suitable for processing smooth-surfaced steel wires and other metallic fibres otherwise difficult to treat.

The present invention will be further illustrated, by way of example, 3Q with reference to the accompanying drawing, in which the single Figure shows a plan view of an apparatus in accordance with the invention with a steel wire passing through.

As illustrated, the apparatus comprises a friction roller 1 which is mounted on a shaft 2 so as to be freely rotatable without drive, in pivot bearings (not further shown), within a guide distance defined by studs 3.

The studs 3 are located in pairs on a base plate 13 and may be displaced therewith in the direction of the arrows 111 to a selectable extent in the same or opposite direction laterally to the guide distance. The steel wire 4 to be twisted is fed to the apparatus subject to the action of a tensional stress, in a stretched state, and passes through the guide distance in the direction of the arrow IV, whereby it enters into a peripheral groove 11 of the friction roller 1 and engages the latter due to the frictional engagement contact in the direction of rotation. The peripheral groove 11 is provided with a cross-section so that its flanks, in the smaller diametrical regions, first extend along a spherically curved line in the proximity of the periphery, to merge into the axial direction. Setting means, Ιθ not shown, permit the shaft 2 of the friction roller 1 to be pivoted in both directions angularly relative to the guide struts, v/ith which the angle ra between the pivotal axis 11-11 and the centre line V-V of the guide distance varies between 90° and a structurally predetermined minimum value.

In the position shown, the friction roller 1 is pivoted through an angle a. The incoming steel wire 4 first reaches the spherical outer region of the roller 1 which rotates at a greater peripheral speed than the flank of the peripheral groove 11 and, in the course of progressive movement, is twisted along the flank in an inward direction. In the outgoing region, starting along the flank of the peripheral groove, the wire 4 has imparted thereto a second equally large rotary impulse in the same direction. The rotary movements derived alone from the longitudinal movement (arrow IV) of the steel wire 4 or the twist produced are elucidated by the rotary arrows associated with the shaft 2 and the out-going steel wire.

Claims (4)

1. CLAIMS :1. Apparatus for twisting fibres, comprising a friction roller mounted so as to be freely rotatable about its longitudinal axis and adjustable -through an angle relative to a line between two fibre guide means located on either side of the friction roller, and having an outwardly 5 flared peripheral groove, the flanks of which in variable diametrical regions form abutting surfaces for the fibre, in which the peripheral groove of the friction roller is provided with flanks v/hich extend conically straight in the inner region of the groove and are convexly curved in the outer region and a merging into the axial direction of the friction roller. 10

2. Apparatus as claimed in claim 1 in which the pivotal axis of the friction roller is adjustable through an angle up to 90° relative to said line between the tv/o guide means.

3. Apparatus as claimed in claim 1 or 2, in which at least one of the guide means is adjustable normal to the delivery directions of the 15 fibre.

4. Apparatus for twisting fibres, substantially as hereinbefore described v/ith reference to and as illustrated in the accompanying drawings.