US3638413A - Magnetic false twist spindle - Google Patents

Abstract

An improved magnetic false twist spindle comprising a tubular spindlette having a locking means for the false twist, a single driving roller attached to a driving shaft, said roller being capable of rotating at high speeds, and annular magnets, said magnets holding the spindlette against the driving roller such that the spindlette is centered axially and laterally. The improvement resides in that the annular magnets are coaxially located at the two ends of the driving roller and in close contact with the enveloping support of the spindle. The poles of the magnets are so located that a complete magnetic circuit results.

Description

United States Patent Raschle [451 Feb. 1,1972

[54] MAGNETIC FALSE TWIST SPINDLE Primary ExaminerDonald E. Watkins Attorney-Sherman and Shalloway [57] ABSTRACT An improved magnetic false twist spindle comprising a tubular spindlette having a locking means for the false twist, a single driving roller attached to a driving shaft, said roller being capable of rotating at high speeds, and annular magnets, said magnets holding the spindlette against the driving roller such that the spindlette is centered axially and laterally. The improvement resides in that the annular magnets are coaxially located at the two ends of the driving roller and in close contact with the enveloping support of the spindle. The poles of the magnets are so located that a complete magnetic circuit results.

2 Claims, 3 Drawing Figures PATENTED FEB 1 I972 E E H m A R F E w I ATTORNEYS This invention relates to a novel magnetic false twist device. More particularly this invention relates to a magnetic false twist device in which the ill effects of Foucault currents are minimized.

False twist devices are often used in processes for producting textured textile yarns. Briefly false twisting comprises feeding the yarn into the false twist device followed by passing the yarn through a heating element somewhat upstream from the false twist device so that it heats the yarn while it is in the false twisted state, and setting the false twist into the yarn during the subsequent cooling.

Since false twisting is such an important step in the production of textured yams, numerous devices have been developed to impart a false twist to the yarn. Generally they comprise a tubular spindlette provided with means to lock the twist and with means to rotate the spindlette. For a long time the rotating means was purely mechanical and comprised various means to push the spindlette against a drive means such as a belt. Later false twist devices were designed which incorporated the magnetic holding of the spindlette against the drive means. These devices are generally called magnetic false twist spindles. The first magnetic false twist spindle comprised a spindlette in contact with at least two spools, these spools having end discs which are positioned parallel to each other,

and mounted on parallel axes which are close enough to each other so as to insure a certain amount of overlap of the end discs so that the spindlette was held against the rims of two pairs of overlapping end discs. A horseshoe magnet held the spindlette against these rims. This device was an important step forward in the art and allowed for the use of very high rotational speeds of the spindlettes, however, this device had one important drawback, the shearing forces created by the two rollers tended to wear the elastic covering on these rims. In view of this drawback a single roller-type magnetic false twist spindle was developed where the spindlette was attached magnetically by a horseshoe magnet against the discs of a single roller. This allowed the spindlette to flow freely without any support except for that created by the magnet acting on the ends of the spindlette which was axially and laterally centered in the poles of the magnet. This type of device was a vast improvement over the previous devices since the elastic coverings on the rim wore more slowly and less power was needed to operate this device. A great number of different devices of this type all having magnets in different shapes have been developed. However, since the magnetic alloys are expensive and machining the same into intricate designs presents a great number of problems, a simple shape for the magnet is preferable It is therefore, not surprising that the use of annular magnets has been suggested for use in a false twist spindle of the monoroller type. However, the use of annular magnets have had the disadvantage of a high polar distance which causes a major loss of power of the magnetic field, and since the magnetic field is also closed through the rotating drive roller, Foucault currents cause harmful breaking effects. To overcome this problem it has been suggested to mold the roller or the rims of the roller from a plastic material; however, due to the heat generated by the Foucault currents this has not been successfully done.

Briefly, the magnetic single-roller false twist spindle of this invention comprises the single driving roller, a freely floating spindlette, two annular magnets placed on the sides of the driving roller in such a way that the spindlette is axially and laterally centered by the magnetic system which acts directly on the ends of the spindlette, and an enveloping support, the improvement which comprises placing the two annular magnets on either side of the driving roller and in close contact with the support so as to close the magnetic circuit through the enveloping support.

It is therefore the primary object of this invention to provide an improved single-roller magnetic false twist spindle.

It is still a further object of this invention to provide an improved single-roller magnetic false twist spindle wherein the polar distance IS greatly reduced and the magnetic circuit is closed through the enveloping support so as to reduce the risk of generating Foucault currents.

Further objects and advantages of the improved apparatus of this invention will become more apparent in the following more detailed description thereof. This description is intended to illustrate the improved apparatus of this invention and is not intended to be [imitative but covers any and all the variations included within the scope of the appended claims.

FIG. 1 is a modified front view along line l-1 as shown in FIG. 2 of the improved single-roller magnetic false twist device of this invention. This view illustrates the path of the magnetic circuit.

FIG. 2 is a side view of the magnetic single-roller false twist spindle of this invention.

FIG. 3 is a top view of the device of this invention.

Referring to FIGS. 1 and 2, the magnetic single-roller false twist device of this invention comprises a single driving roller 4 having two end discs 14 and 24 so that rims as shown form a rolling contact for the tubular spindlette 5. Spindlette 5 may be provided with a middle centering ring 35 and ends 15 and 25 which are constructed to roll on end discs 14 and 24. Spindlette 5 is also provided with a false twist device such as crossed bars. End discs 14 and 24 may be provided with an elastic covering, such as polyurethane, which is commonly used with magnetic single-roller false twist spindles. These elastic covers are not necessary, however, for the operation of this device. The driving roller 4 is attached to drive shaft 6 which has a pulley or wheel 8 in contact with driving belt 9 which in turn is driven by a motor or some other device (not shown). Driving shaft 6 is supported by supporting means 7 and 17, such as ball bearings. On either side of driving roller 4 are two split rings 10 and 11 which form the pole shoes of annular magnets l and 2. Annular magnets l and 2 are so placed in enveloping support 3 so as to have contact with enveloping support 3. Magnets 1 and 2 have opposing magnetic poles facing each other, i.e., magnet 1 has the north pole facing magnet 2s south pole. Referring to FIG. 3, the location of the slits 20 and 21 and split rings 10 and 11 is shown. The spindlette should be centered between these slits. This system allows for the magnetic field to flow as shown in FIG. 1 by arrows l2 and 13. The magnetic field flows from magnet 1 through pole shoe 10 through the spindlette 5 to pole shoe 11 through magnet 2 and casing 3 back to magnet 1, thus completing the circuit. This completed magnetic circuit holds the spindlette 5 against end discs 14 and 24 of driving roller 4. This reduces the distance between the slits to an absolute minimum.

The casing 3, spindlette 5 and pole shoes 10 and 11 should be constructed out of a conductive material such as iron and other similar metals and alloys. Furthermore, spindlette 5 should also be constructed out of easily magnetizable material so that it is easily held against end discs 14 and 24. Spindlette 5 should also be provided with means to lock the false twist in the yarn to be textured while passing through spindlette 5.

What is claimed is:

1. In a magnetic false twist spindle comprising a tubular spindlette having locking means for the false twist, a driving shaft, a single driving roller attached to the driving shaft, said roller capable of rotating at high speeds, a. pair of annular magnets which hold the spindlette axially and laterally centered against the single driving roller and an enveloping support, the improvement which comprises the placing of the annular magnets coaxially at the two ends of the driving roller said magnets being positioned so that their opposite magnetic poles are facing and said magnet being in close contact with the enveloping support of the spindle so that a complete magnetic circuit is fonned.

2. The magnetic false twist spindle of claim 1 wherein the annular magnets further comprise two split rings, said split rings being so positioned that the center of the spindlette is between the lips of the split rings so that there is a minimum of distance between the spindlette and the lips of the split rings.

Claims (2)

1. In a magnetic false twist spindle comprising a tubular spindlette having locking means for the false twist, a driving shaft, a single driving roller attached to the driving shaft, said roller capable of rotating at high speeds, a pair of annular magnets which hold the spindlette axially and laterally centered against the single driving roller and an enveloping support, the improvement which comprises the placing of the annular magnets coaxially at the two ends of the driving roller said magnets being positioned so that their opposite magnetic poles are facing and said magnet being in close contact with the enveloping support of the spindle so that a complete magnetic circuit is formed.

2. The magnetic false twist spindle of claim 1 wherein the annular magnets further comprise two split rings, said split rings being so positioned that the center of the spindlette is between the lips of the split rings so that there is a minimum of distance between the spindlette and the lips of the split rings.

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