US3363409A

US3363409A - Rotary tube for crimping filamentary synthetic fibers by imparting thereto a false twist

Info

Publication number: US3363409A
Application number: US429961A
Authority: US
Inventors: Schwabe Kurt; Lang Otto
Original assignee: Kugelfischer Georg Schaefer and Co
Current assignee: IHO Holding GmbH and Co KG
Priority date: 1964-02-17
Filing date: 1965-01-29
Publication date: 1968-01-16
Anticipated expiration: 1985-01-16
Also published as: DE1435522A1; FR1424287A; GB1058872A; DE1435522C3

Abstract

A false-twist tube has the twist imparting means, for example a pin, located substantially midway between the ends of the tube, there being a transverse aperture or bore to enable the yarn which is to be false twisted to be passed about the pin. The tube is provided with a central portion of larger diameter than the rest of the tube and which is magnetically urged against the driving discs. The central portion may be formed integrally with the rest of the tube, or tubular portions of tool steel may be press-fitted in a central portion of alloy steel.

Description

Jan. 16, 1968 K. SCHWABE ETAL 3,363,409

ROTARY TUBE FOR CRIMPII G FILAMENTARY SYNTHETIC FIBERS BY IMPARTING THERETO A FALSE TWIST Filed Jan. 29, 1965 FIG. 7 FIGZ I m an ers E 1 b #15190 rneys United States Patent 3 Claims. oi. 57-77:

For the purpose of imparting a false twist to filamentary synthetic fibers and thus crimping the said fibers, there has been proposed the use of rotary tubes provided with a twist-inducing arrangement. Thus far it has been conventional to construct such twisting tubes in the manner shown in FIG. 1 of the appended drawings. The thread or yarn 1 to be crimped is guided through the longitudinal bore 2 of the tube body shown in longitudinal cross-section in FIG. 1; the central portion 3 of the tube having a wall of relatively large thickness is provided at its ends with annular pole shoes 4 and 5. For the purpose of crimping the said filamentary yarn 1, the central portion 3 of the tube body is urged against pairs of friction discs (not shown) by the action of magnetic forces which are produced by a magnetic stator body (not shown) and act upon the pole shoes 4 and 5 of the central portion 3 of that part of the tube which, together with the central portion, constitutes a magnetic armature body. The

terminal portions

6 and 7 of the tube which are of smaller wall thickness than the central portion receive the filament where it enters and leaves, respectively, the bore of tube. Connected to the terminal portion 7 on the exit end of the tube is a bifurcation 8 which carries, as a means to impart the desired twist to the filament, a pin 9 extending transversely of the axis of the tube and wrapped by the filament to be twisted. During operation of the tube the filament will form a balloon 11 extending between the twist imparting means 9 and a pigtail guide 10.

FIG. 1 illustrates the most Widely adopted known construction of a rotary tube serving to impart a false twist to filamentary yarns of synthetic material for the purpose of crimping them. Besides the construction of FIG. 1, there has also become known a construction in which the twist imparting means 9 are not arranged in the manner shown in FIG. 1, i.e. at the point at which the filament 1 emerges from the tube, that is to say, at the free end of the tubular terminal portion 7, but at the entry end thereof, i.e. at the free end of the tubular terminal portion 6 of the tube.

These two known arrangements of the twist imparting means in rotary tubes serving to impart a false twist to filamentary yarns suffer from a drawback in that the said bifurcation (carrying the reference numeral 8 in FIG. 1) of the twist imparting means which is required to permit the threading of the yarn is subject to distortion by the large centrifugal forces caused by the high speed of the tube which in some cases may greatly exceed 200,000 revolutions per minute, this distortion caus- 6 ing the twist imparting pin, such as shown at 9 in FIG. 1, to work loose in their retaining holes, to be bent out of shape or to be broken. Another drawback inherent in the known arrangement of the twist imparting means at the free end of the rotary tube is to be seen in the fact that yarn balloons of different size are formed upstream and downstream of the twist imparting pins. The different size of these balloons is the result of the fact that the balloon formed at the entrance of the bore of the tube is constrained by the wall of the bore, whereas the other balloon formed at the exit of the tube is not subjected to any such restraint. These different conditions prevailing in the entry and exit regions of the thread result in the setting-up of undesirable stresses in the thread, such stresses tending to promote slippage of the thread in relation to the twist imparting pin and interfering with the accumulation of twist turns at the said pin, the result being that there occur in the running yarn portions in which the twist has not been removed by an untwisting action. I

The aforedescribed drawbacks inherent in rotary tubes incorporating twist imparting means serving to impart a false twist to filamentary synthetic fibers to be crimped are obviated according to the invention by the arrangement of the twist imparting means at a point which is equidistant from the yarn entry and exit zones and by the provision of an aperture extending transversely of the axis of the rotary tube, the twist imparting means being disposed in the said aperture which permits the yarn to be threaded through the tube. This arrangement ensures that the quality of the crimped yarn is no longer reduced by the presence of non-uniform stresses, this permitting the production of crimped yarns of high and uniform quality.

According to another feature of the invention, there may be provided an armature body made of alloy steel having a longitudinal bore into the ends of which are inserted press-fitted tubular bearing members made of tool steel. This arrangement ensures that the rotary tube made of steel which in operation rotates in a magnetic field whereby it is subjected to the action of eddy currents will not be heated to an undesirable extent at the high rotary speeds required. The use of alloy steel in the armature body of the rotary tube, i.e. in its central portion and the two annular pole shoes, makes it possible to limit the heating of the tube to a low value without interfering with the desired mechanical and magnetic conditions. Since the said tubular bearing members made of tool steel are press-fitted in the free ends of the armature body it is no longer necessary to perform the ditlicult machining operation of providing a narrow longitudinal bore in the bearing members.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing, illustrating a preferred embodiment of the invention, wherein:

FIG. 1 is a longitudinal cross-sectional view of a rotary tube of known design;

FIGS. 2 and 3 are longitudinal cross-sectional views of two different embodiments of the invention in which the rotary tube is of single-piece construction and made of steel;

FIG. 4 is a longitudinal cross-sectional view of a third embodiment in which the armature body consists of alloy steel, whereas the tubular bearing members are made of tool steel.

As shown in FIG. 2, the armature body 24 of the rotary tube is provided centrally between its ends with an aperture 12 extending transversely of its longitudinal axis. A twist imparting pin 13 extends perpendicularly to both the axis of the rotary tube and the axis of aperture 12, the aperture making it possible to wrap the yarn 14 to be twisted around the pin 13. The arrangement of the twist imparting means 13 at substantially equal distances from the entry end 15 and the exit end 16 of the rotary tube provides for the advantages mentioned earlier, these advantages resulting in the aforementioned increase in the quality of the crimped yarn.

FIG. 3 is a longitudinal cross-sectional view extending at right angles to the plane of the view shown in FIG.

2; in FIG. 3, the twist imparting pin 13 which is pressfitted in a bore of the armature body 24 extends transversely of the axis of the rotary tube. As indicated at 17 in FIG. 3, the twist imparting pin is provided with a centrally located throat section to be Wrapped by the yarn to be imparted a false twist.

Shown in FIG. 4 vis another embodiment of the invention comprising an armature body 18 made of alloy steel. The said armature body is provided With a longitudinal bore 19 of relatively large diameter and With a short transverse bore 20, the twist imparting pin 21 being pressfitted into the bore 20. Press-fitted in each of the two terminal portions of the armature body 18 is a tubular bearing

member

22, 23 made of tool steel. The provision of these tubular bearing members aifords the advantages indicated earlier in this specification.

What is claimed is:

1. An apparatus for twisting yarn comprising an armature body having a longitudinally extending bore through which the yarn passes and a transversely extending bore located substantially equidistant from the ends of said body; and a yarn retaining member disposed in said transversely extending bore and extending at right angles to each of said bores, said member being adapted to receive said yarn to fix same with respect to said armature body, so that upon rotation of said body about its longitudinal axis, a twist will be imparted to said yarn.

2. The apparatus of claim 1, wherein said l0ngitudi nally extending bore is of a length sufiieient to eliminate ballooning of the yarn therein.

3. The apparatus of claim 1, wherein said armature body includes an outer portion of alloy steel and two tubular bearing members of tool steel press fitted into the ends of said outer portion, said pin being press fitted into said transversely extending bore.

References Cited UNITED STATES PATENTS 2,557,104 6/1951 Hegedus 57-7733 2,659,193 11/1953 Hegedus 57-77.33 2,821,062 1/1958 Boillat et a1. 5777.33 2,928,229 3/1960 Haas 5777.3 3,035,399 5/1962 Scragg 57-77.45 3,058,289 10/1962 Raschle 57-77.3 3,059,409 10/1962 Schussler 57-77.3 X 3,090,190 5/1963 Bousso et al 5777.3 X 3,114,235 12/1963 Griset 57-773 X FOREIGN PATENTS 204,5 32 11/ 1956 Australia. 1,317,476 1/1963 France. 1,362,081 4/ 1964 France.

925,261 5/ 1963 Great Britain.

' FRANK J. COHEN, Primary Examiner.

D. WATKINS, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,363 ,409 January 16 1969 Kurt Schwabe et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below Column 2, line 50, strike out "two different embodiments" and insert instead an embodiment line 53, for "third" read second Signed and sealed this 22nd day of April 1969.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer

Claims

1. AN APPARATUS FOR TWISTING YARN COMPRISING AN ARMATURE BODY HAVING A LONGITUDINALLY EXTENDING BORE THROUGH WHICH THE YARN PASSES AND A TRANSVERSELY EXTENDING BORE LOCATED SUBSTANTIALLY EQUIDISTANT FROM THE ENDS OF SAID BODY; AND A YARN RETAINING MEMBER DISPOSED IN SAID TRANSVERSELY EXTENDING BORE AND EXTENDING AT RIGHT ANGLES TO EACH OF SAID BORES, SAID MEMBER BEING ADAPTER TO RECEIVE SAID YARN TO FIX SAME WITH RESPECT TO SAID ARMATURE BODY SO THAT UPON ROTATION OF SAID BODY ABOUT ITS LONGITUDINAL AXIS, A TWIST WILL BY IMPARTED TO SAID YARN.