US2846728A - Apparatus for producing staple fibre yarns from continuous filaments - Google Patents

Description

Aug 12, 1958 R. WILDBOLZ 2,846,728 APPARATUS FOR PRODUCING STAPLE FIBRE YARNS FROM CONTINUOUS FILAMENTS Filed Feb.

INVENTOR: EUDOL F l V/LDBOLZ.

mi A TTORNEV United States Patent G APPARATUS FOR PRODUCING STAPLE FIBRE YARNS FROM CONTINUOUS FILAMENTS Rudolf Wildbolz, Winterthur, Switzerland, assignor to Joli. Jacob Rieter & Cie., Wintertliur, Switzerland, a corporation of Switzerland Application February 7, 1955, Serial No. 486,311

Claims priority, application Switzerland February 8, 1954 4 Claims. (Cl. 19-.6)

The present invention relates to an apparatus for producing staple fibre yarns from continuous thermoplastic synthetic filaments.

It has been found that filaments of thermoplastic syn thetic substances, such as are known in the trade as nylon, Perlon, Therylen, and the like, cannot be processed in drafting frames, for example of the type disclosed in my copending application Serial No. 367,281, filed July 10, 1953, as successfully as other synthetic fibres. The reason is the great elasticity of the aforementioned filaments. The tension in the filaments causes them to recoil immediately after being broken by tearing or by means of special breaking devices. The ends of the filaments frequently form kinks or curls. The curled ends have the tendency of forming nips during the subsequent tensioning operation. Sometimes, orderly breaking of the fibres is not possible.

It is an object of the present invention to provide an apparatus for producing staple fibre yarns from continuous filaments in which the disadvantages of conventional methods and devices are avoided, by subjecting the tensioned filaments to a heat treatment prior to breaking. According to the invention, the direction of longitudinal movement of the filaments is controlled by a heated element having a surface portion slidably supporting the tensioned filaments whereby heat is transferred to the filaments by conduction. The elastic elon gation of the individual filaments, which are stressed almost to the breaking point, is fixed by the heat treatment so that the elastic recoil after breaking of the filaments is considerably reduced and curling is prevented. It has been found that heating of a guide element for controlling the direction of movement of the filaments into the breaking device, as has been disclosed in my copending application, Serial No. 367,281, filed July 10, 1953, is particularly effective. No additional heating means are required and guiding and heating of the filaments take place simultaneously.

The novel features which are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself however and additional objects and advantages thereof will best be understood from the following description of embodiments thereof when read in conjunction with the accompanying drawing, in which Fig. l is a diagrammatic part sectional elevational view of an apparatus according to the invention;

Fig. 2 is a perspective view of a heated guide element assembly forming part of the apparatus shown in Fig. 1;

Fig. 3 is an end View of a combined guide and heating element forming part of the assembly shown in Fig. 2;

Fig. 4 is a diagrammatic perspective illustration of a modified heating element according to the invention.

The same numerals designate the same parts in all figures.

The drafting frame shown in Fig. 1 comprises three feed rolls 1, 2, and 3 and a pair of delivery rolls 4. A guide rail 5 is interposed between the nip of the feed rolls 2 and 3 and a breakingelement 8. Guide and heating plates 9, one per each filament bundle, are mounted in spaced relation on the rail 5. The filaments form a bundle 7 which is in the form of a ribbon or band sliding over a part of the plates 9, the size of the part depending on the relative angular position of the filament bundles or bands and of the plates. The filaments become heated while sliding over a guide portion 6 of the plates 9, the broad side of the bands of heated filaments being engaged by the cutter 8 which deflects and breaks the filaments whereupon they are withdrawn by the delivery rolls 4 at increased speed. The circumferential speeds of the rolls 1, 2, and 4 is so adjusted that the filaments are tensioned to the desired extent.

By changing the elevation of the rail 5, i. e. by changing the distance between the rail and the roll 2, the length of the filaments which is in contact with the plate and consequently the heating effect can be changed.

Fig. 3 illustrates an individual guide and heating plate 9. The end 11 of the plate, which end is opposite the guiding end 6 of the plate, is bent around an electric heating element 10. Since the plate portion 11 extends almost completely around the element 10, the plate 9 is effectively heated. The ends of the heating elements 10 are interconnected by insulated wires 12. In the arrangement shown in Fig. 2, the heating elements are connected in series, the wires 12 connected to the outer ends of the heating elements 10 for the outer plates 9 being connected to a source of electricity, not shown. Each heating element may be individually electrically connected with a source of electric current, i. e. the heating elements may be wired in parallel, if desired.

Fig. 4 illustrates a modified guide and heating device in which a single guide member 13 is provided which has extensions 14 adjacent to the paths of the filament bundles, the extensions 14 being spaced to follow the spacing of the filament bundles. The rectangularly shaped extensions 14 are connected with the rail 5. A thin heating foil 15 covers the surface of the guide 13 and of the extensions 14, which surface faces the filament bundles. A layer 16 of electrically insulating material is interposed between the heating foil 15 and the guide 13 with its extensions 14. Electric current is supplied to the heating foil 15 at one end of the guide 13 by a conductor 17 and is conducted away at the other end of the guide.

The heating plates 9 and the foil 15 are preferably made of chrome-nickel steel which has good guide characteristics with respect to polyamide filament bundles. The chrome-nickel steel foil is honed after it has been mounted on the filament guides.

It has been found particularly efiective, if a twister 18 is arranged in the immediate neighborhood of the drafting frame, so that the staple fibres are intertwisted before they regain their resiliency which is temporarily reduced by heating.

What is claimed is:

1. A drafting arrangement comprising, in combination, feed rollers, delivery rollers, breaking means interposed between said feed and delivery rollers at a fixed distance from the latter, for producing a staple fibre ribbon from a filament bundle, and adjustable guide means separate and spaced from said breaking means for causing the filament bundle to enter said breaking means at an adjustable angle, said guide means including a heating element for heating the passing filament bundle prior to breaking.

2. A drafting arrangement as defined in claim 1 including in the combination intertwisting means receiving the ribbon of staple fibres from said delivery rolls for intertwisting the staple fibres.

3. Apparatus for converting a bundle of continuous thermoplastic synthetic filaments into a sliver of staple fibres comprising a set of feed rolls adapted to nip the filaments and to feed the same into a reducing zone at a given speed, a set of delivery rolls adapted to nip the filaments and to withdraw the same from said zone at an increased speed, breaking means interposed between said feed rolls and said delivery rolls for intermittently breaking the filaments, adjustable guide means interposed between said .feed rolls and said breaking means for directing the filaments at an adjustableangle into said breakingmeans, and heating means integral with said guide means for heating the latter and the filaments guided thereby prior to the entry of the filaments into said breaking means.

4. Apparatus for converting a bundle of continuous thermoplastic synthetic filaments into a ribbon of staple fibres comprising, in combination, a set of feed rolls adapted to nip the filaments and to feed the same in the form of a band into a reducing zone at a given speed, a set of delivery rolls adapted to nip the filaments and to withdraw the same from said zone at an increased speed, a heated element interposed between said feed rolls and said delivery rolls and having a surface portion slidably supporting the tensioned filaments for heating the latter by conduction, and breaking means interposed between said heated element and said delivery rolls and engaging the broad side of the band of filaments for intermittently deflecting and breaking the filaments after they have been heated.

References Cited in the file of this patent UNITED STATES PATENTS 2,249,809 Dickie et al July 22, 1941 2,255,755 Bell Sept. 16, 1941 2,432,355 Truitt Dec. 9, 1947 2,653,355 Essman Sept. 29, 1953 2,777,276 Klein Jan. 15, 1957

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