US3516614A

US3516614A - Process and device for winding up threads

Info

Publication number: US3516614A
Application number: US716774A
Authority: US
Inventors: Gunther Bauer; Jakob Bucher
Original assignee: Hoechst AG
Current assignee: Hoechst AG
Priority date: 1967-04-07
Filing date: 1968-03-28
Publication date: 1970-06-23
Anticipated expiration: 1987-06-23
Also published as: CH483978A; DE1660319A1; FR1561631A; NL6804193A; BE713375A; ES352449A1; GB1225527A

Description

June 23, 1970 BAUER ET AL 3,516,614

PROCESS AND DEVICE FOR WINDING UP THREADS Filed March 28, 1968 .4 Sheets-Sheet 1 FIG. 1

INVENTORS GUNTHER BAUER JAKOB BUCHER H ATTORNEYS June 23, 1970 a. BAUER ET AL 3,516,614

PROCESS AND DEVICE FOR WINDING UP THREADS Filed March 28, 1968 4 Shoots-Shack :3

V 4 9 v M Q- hyperbole for L 1 hyperbole for L hyperbole for L INVENTORS GUNTHER BAUER JAKOB BUCHER 5 ATTORNEYS June 23, 1970 Q a u ET AL 3 516 614 PROCESS AND DEVICE FOR WINDING UP THREADS Filed March 28, 1968 4 Sheets-Sheet 3 INVENTORS HEW. ATTORNEYS June 23, 1970 BAUER ET AL 3,516,614

I PROCESS AND DEVICE FOR WINDING UP THREADS Filed March 28, 1968 .4 Shaots-8hoot 4 INVENTORS GUNTHER BAUER JAKOB BUCHER il ATTORNEYS United States Patent Int. Cl. B6511 54/02 US. Cl. 24218 5 Claims ABSTRACT OF THE DISCLOSURE The present invention provides a process for winding up a drawn synthetic thread on a tube with a substantially constant tension of the thread during the winding operation. During the winding operation the length of the free thread between the point where it leaves the element which brings about a traverse motion of the thread and the point where it meets the bobbin does not change or changes only slightly.

The present invention relates to the winding up of threads with a substantially constant winding tension.

It has been proposed to Wind up drawn synthetic threads on tubes driven by a driving drum, the traverse motion of the thread being brought about by a split drum. It has also been proposed to bring about the traverse motion by traversing thread guides.

When bobbins are wound with the aid of suitable devices a uniform winding tension is desirable during winding. A uniform winding tension promotes uniformity in the properties of the thread, for example, the degree of shrinkage, dyestuif affinity and elastic modulus. Moreover, a constant winding tension is favoured from the point of view of safety; if the tension is too low the thread often winds round the driving drum instead of building up the bobbin. When a thread is wound up a certain length thereof is free between the point where the thread leaves the traversing element, for example the outer surface of a split drum, and the point Where it is wound on the bobbin. In this specification this length of thread is referred to as the drag length. In the usual winding processes the drag length changes as the bobbin is built up, i.e. during the winding operation.

The present invention is based on the observation that the winding tension remains constant during winding when the drag length is maintained constant. Absolute constancy of the drag length is preferred, but the Winding tension is still sufficiently constant when, during winding, the drag length increases by at most one quarter of its initial length and decreases by at most one tenth of its initial length.

There are a number of diiferent methods which may be used to maintain the drag length substantially constant, the method suitable for any particular type of winding equipment depending, for example, on the type of traversing element used, the relative sizes of various parts of the winding equipment and the method used for driving the bobbin.

FIGS. 1-4 are schematic illustrations of various arrangements exemplifying the principles of this invention.

It has been found, for example, that when a split drum is used as traversing element the drag length and, thus, the winding tension may be maintained constant if the path followed by the centre of the bobbin during the winding operation represents a hyperbola which can be constructed point by point. The construction of such a ice hyperbola will now be described with reference to FIG. 1 of the accompanying drawings. FIG. 1 shows, diagrammatically, a thread being wound on a bobbin 1 driven by a driving drum 2 with traverse motion of a thread 3 brought about by a split drum 4.

Referring to the drawings:

1M is the centre of the bobbin 1 R is the respective radius of the bobbin 1 M, is the centre of the driving drum 2 R, is the radius of the driving drum 2 M is the centre of the split drum 4 R is the inner radius of the split drum 4 and R is the outer radius of the split drum 4 The thread 3 leaves the circle drawn round M at a distance R at B and leaves the split drum at D. The thread 3 meets the bobbin at E. The distance between points D and E corresponds to the free length of the thread, i.e. the drag length L which, according to the present invention, should be maintained constant. With an increasing diameter of the bobbin during winding the position of its centre changes. For each possible radius of the bobbin R the position of the centre of the bobbin M is the intersection of two circles drawn round M, and M so that if the radii of these circles are known for any given value of R the position of M can be found. The radius of the circle round M, is equal to the sum of the radius of the driving drum R, plus the respective radius of the bobbin R,,,. The radius of the circle round M, is the hypotenuse of a right-angled triangle between points M C and M which can be constructed for any position of the points B, D and B.

One short side of the triangle M,CM is formed by the sum of the inner radius of the split drum R (M B) plus the respective radius of the bobbin R (distance EM =distance BC) and the other short side of the triangle is formed by the distance between point B and point D plus the drag length 1,,(DE), (distance CM -=distance BE). The triangle M BD is congruent for each position of D on the outer circumference of the split drum because the inner radius R and the outer radius R are constant and the right angle between the thread 3 and the inner radius of the split drum R is always maintained at B. BD is therefore constant and as, according to the present invention, L is to be maintained constant, the short side CM of the triangle M CM is constant during the whole winding operation. The other short side M C (=R -l-R of the triangle M CM varies during winding because of the change in the radius of the bobbin R For any given value of R it is possible to calculate Rg-l-R and the hypotenuse of the triangle M CM so it is therefore possible to calcuate the position of M for any value of R It is found that, for L to be maintained constant, the centre of the bobbin M should describe a path 5 which is part of a hyperbola (unless R =R see below).

Although winding up while maintaining the drag length L, constant is preferred according to the present invention, it has been found that threads having uniform properties can be obtained with suflicient safety of operation when, during the winding operation, the drag length L, increases by at most one quarter of its initial value and decreases by at most one tenth of its initial value.

With the use of the afore-described construction and considering the maximum and minimum values of the drag length a range can be determined within which the path described by the centre of the bobbin during the winding operation must be situated according to the process of the invention. This is shown in FIG. 2. If the initial drag length L is to be maintained constant, the

Patented June 23, 1970 centre of the bobbin must describe a hyperbolic orbit from M to M (hyperbola for L while the radius of the bobbin increases from R to R When during the winding operation an increase by one quarter of the initial length of the drag length is tolerated, the use of the value 4 L gives a hyperbolic orbit which is shown on FIG. 2 below the hyperbola for L whereas a shortening of the free drag length L by one tenth of the initial length to L gives the upper hyperbola (hyperbola for L According to the invention the path of the centre of the bobbin M during the winding operation must be situated within the zone limited by the two outer hyperbolas.

The process of the invention is easy to carry out on an industrial scale because numerous devices can be used for guiding the centre of the bobbin on a path as stipulated by the conditions specified above.

To carry out the process of the invention it is possible, for example, to use a device comprising a split drum for giving traverse motion to the thread, a driving drum and a tube set on a bobbin holder. The bobbin built up on the tube is driven by the driving drum. The bobbin holder is fitted in a known manner on a swingable lever. The length of the lever and the position of its point of rotation are chosen in such a manner that the circle described by the centre of the bobbin during the winding operation substantially approaches the optimum hyperbolic orbit for the initial drag length used and is situated within the zone limited by the two outer hyperbolas. The length of the lever arm and the position of its point of rotation can be readily determined from three points of the optimum hyperbolic orbit by construction of the circle described by the centre of the bobbin as the point of intersection of two lines, each line perpendicularly bisecting a chord drawn between two of the three points chosen.

Alternatively, the process of the invention can be carried out with a device in which the movable bobbin holder is fitted on a swingable lever eccentrically supported in known manner or by any other means suitable for guidance along the required path.

According to a further preferred embodiment of the process of the invention a constant drag length L and a constant winding tension may be maintained by guiding the centre of the bobbin M on a straight line. This method of maintaining a constant drag length may be used when the inner radius of the split drum R and the radius of the driving drum R are equal. This is shown on FIG. 3. The straight line representing the course of the centre of the bobbin M is perpendicular to the line between the centres of the driving drum M, and the split drum M With the use of known equipment it is very easy to guide the centre of the bobbin on a straight line.

The process of the invention can also be carried out with known devices in which with an increasing diameter of the bobbin the bobbin is not moved away from the driving drum but the driving drum is moved while the axis of the bobbin remains in a constant position. With a device of this type the driving drum can only drive those bobbins which start simultaneously winding the thread. With this mode of execution the conditions stipulated above must be suitably adapted. Other devices can also be used to carry out the process of the invention, for example a device in which the bobbin is directly driven by a split drum with omission of the driving drum.

It is quite obvious that devices may also be used for the process of the invention in which the traverse motion of the thread is brought about by a traversing thread guide (oscillatable thread guide). Such a mode of execution of the process is illustrated in FIG. 4. If the thread is to be wound up with constant drag length the appropriate path of the centre of the bobbin M is a straight line 7 which is perpendicular to the projected direction of the thread as it leaves the thread guide 6, the point of intersection E of the line 7 with the centre line of the thread 3 being below the traversing thread guide 6 by the distance DE=L In this case D is the point where the thread leaves the traversing thread guide (which corresponds to the point where the thread leaves the split drum). Thus, when the arrangement shown in FIG. 4 is used, a constant drag length can be obtained by guiding the centre of the bobbin M on a straight line.

Since, according to the invention, a change of the drag length L during the winding operation by an increase of A of the initial drag length and a decrease by of the initial drag length is allowed, a zone is established between a straight line 8 (see FIG. 4), which is by the distance W L below the thread guide 6, and a straight line 9, which is by the distance L below the thread guide 6. The path of the centre of the bobbin should be situated within this zone. When the centre of the bobbin M describes an arc of a circle, i.e. with the use of a swingable lever, the radius and the centre of the circle can be determined in the manner described above. The extreme case of such a circular path is a path 10 of the centre of the bobbin M marked in FIG. 4. With this path, winding of the bobbin starts at the intersection of the straight line 7 (which is below the traversing thread guide by the distance L with a circle round M having the radius R +R In its culmination point the circular path 10 touches the straight line 8 situated below the traversing thread guide 6 at a distance L It ends in the intersection of the straight line 9 (which is situated below traversing thread guide 6 at the distance L with a circle round M having the radius R +R A circle complying with these conditions has the radius R.

What is claimed is:

1. A process for winding up a drawn synthetic thread on a tube with traverse motion of the thread and driving of the building bobbin with a driving drum, with substantially constant winding tension, wherein, during winding, the length of the free thread between the point where it leaves the traversing element and the point where it meets the bobbin increases by at most one quarter of its initial value and decreases by at most one tenth of its initial value, and wherein the traverse motion of the thread is brought about by a split drum and the centre of the bobbin is guided on a path situated between two hyperbolas which are constructed point by point with an increasing radius of the bobbin as intersection of two circles, one circle drawn round the centre of the driving drum with a radius corresponding to the sum of the radius of the driving drum plus the respective radius of the bobbin, the other circle drawn round the centre of the split drum with a radius equal to the hypotenuse of a right-angled triangle, one short side of which is formed by the sum of the inner radius of the split drum plus the respective radius of the bobbin and the other short side of which is formed by the sum of the length of the inner radius of the split drum plus the respective radius of the bobbin and the other short side of which is formed by the sum of the length of the thread between the point where it leaves the inner circle of the split drum and the point where it leaves the split drum plus the length of the free thread between the point where it leaves the split drum and the point where it meets the bobbin, for the construction of the one hyperbola the length of the free thread being 7 of its initial value and for the construction of the other hyperbola the length of the free thread being W of its initial value.

2. The. process for winding up a drawn synthetic thread on a tube with traverse motion of the thread and driving of the building bobbin with a driving drum, with substantially constant winding tension, wherein, during winding, the length of the free thread between the point where it leaves the traversing element and the point where it meets the bobbin increases by at most one quarter of its initial value and decreases by at most one tenth of its initial value during winding, wherein the traverse motion of the thread is brought about by a split drum and the centre of the bobbin is guided on a path which is constructed point by point with increasing radius of the bobbin as intersection of two circles, one drawn round the centre of the driving drum with a radius corresponding to the sum of the radius of the driving drum plus the respective radius of the bobbin, and the other circle drawn round the centre of the split drum with a radius that is equal to the hypotenuse of a right-angled triangle, one short side of which is formed by the sum of the inner radius of the split drum plus the respective radius of the bobbin and the other short side of which is formed by the distance, which is maintained constant during winding, between the point where the thread leaves the inner circle of the split drum and the point where it meets the bobbin.

3. A device for winding up a drawn synthetic thread on a tube with traverse motion of the thread and driving of the building bobbin with a driving drum, with substantially constant winding tension, wherein, during winding, the length of the free thread between the point where it leaves the traversing element and the point where it meets the bobbin increases by at most one quarter of its initial value and decreases by at most one tenth of its initial value, comprising a split drum to bring about a traverse motion of the thread, a supported bobbin holder movably mounted on a' swingable lever with a tube, and a driving drum to drive the bobbin, wherein means are provided to guide the centre of the bobbin during winding on a path situated between two hyperbolas constructed point by point with increasing radius of the bobbin as intersection of two circles, one circle drawn round the centre of the driving drum with a radius corresponding to the sum of the radius of the driving drum plus the respective radius of the bobbin, the other circle drawn round the centre of the split drum with a radius that is equal to the hypotenuse of a right-angled triangle one short side of which is formed by the sum of the inner radius of the split drum plus the respective radius of the bobbin and the other short side of which is formed by the sum of the length of the thread between the point where it leaves the inner circle of the split drum and the point where it leaves the split drum plus the length of the free thread between the point where it leaves the split drum and the point where it meets the bobbin, for the construction of the one hyperbola the length of the free thread being A of the initial length thereof and for the construction of the other hyperbola the length of the free thread being W of the initial length thereof.

4. A device for winding up a drawn synthetic thread on a tube with traverse motion of the thread and driving of the building bobbin with a driving drum, with substan tially constant winding tension, wherein, during winding, the length of the free thread between the point where it leaves the traversing element and the point where it meets the bobbin increases by at most one quarter of its initial value and decreases by at most one tenth of its initial value during winding, comprising a split drum to bring about a traverse motion of the thread, a movably supported bobbin holder with tube and a driving drum to drive the bobbin, wherein means are provided to guide the centre of the bobbin during winding on a path which is constructed point by point with increasing radius of the bobbin as intersection of two circles, one drawn round the centre of the driving drum with a radius corresponding to the sum of the radius of the driving drum plus the respective radius of the bobbin, the other circle drawn round the centre of the split drum with a radius that is equal to the hypotenuse of a right-angled triangle, one short side of which is formed by the sum of the inner radius of the split drum plus the respective radius of the bobbin and the other short side of which is formed by the distance, which is constant during winding, between the point where the thread leaves the inner circle of the split drum and the point where it meets the bobbin.

5. A device as set forth in claim 3 wherein the bobbin holder is mounted on the swingable lever, the length of the lever and the position of its point of rotation being determined from three points of the optimum hyperbola by construction of the circle described by the centre of the bobbin as the point of intersection of two lines, each line perpendicularly bisecting a chord drawn between two of the three points chosen.

References Cited UNITED STATES PATENTS 2,752,100 6/ 1956 Strange. 2,811,317 10/1957 Herbert et al. 3,008,658 11/1961 Akers. 3,009,661 11/1961 Akers.

NATHAN L. MINTZ, Primary Examiner UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,51 6,61 14. Dated June 23, 1 970 Gunther Bauer and Jakob Bucher Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1 lines 55-57, delete "inner length of the" SELED JAN 5 1971 Atteat:

Edward M. Flmhm J Aucsting Officer mm 3, A: 33.

Gollnisaioner of Patents FORM PO-IOSO (0-69) USCOMNPDC 5037mm n u 5 GOVERNMENT rammm ornc: In: o-scs-ua