US3393877A - Winding process for chemical threads and apparatus for the execution of the process - Google Patents

Description

July 23, 1968 w WEBER 3,393,877

WINDING PROCESS FOR CHEMICAL THREADS AND APPARATUS FOR THE EXECUTION OF THE PROCESS Filed April 28, 1966 INVENTOR. WOLFGANG WEBER ATT'YS United States Patent 6 Claims. cl. 242 1s ABSTRACT OF THE DISCLOSURE A process and apparatus for winding threads in which the vibrations of the winding body caused by thread ridges or bulges are damped and wherein the problem of thread ridge or bulge formation is attacked as soon as it begins to occur. The damping is accomplished by means of a brake member which rides on a fixed braking surface. The movement of the winding body is damped both in a direction away from a drive roller and in a direction toward the drive roller. The dampening action further interrupts the frictional drive of the winding body which serves to eliminate the thread ridges and bulges. The apparatus also contemplates adjustable tension means for controlling the tension of the brake against the braking surface.

The present invention relates to a process for winding endless, especially freshly stretched, chemical threads in random winding on bobbins which are fully rotatable on a swinging arm and are driven by means of drive roller. More particularly, the invention is directed to a process in which the oscillating movements of the bobbin and swinging arm resulting from the formation of a nonuniform winding are damped, as well as to an apparatus for the execution of the process.

In the random winding of threads on a winding body which is carried on a swinging arm, is freely rotatable, and is driven by means of a drive roller, it is a well-known fact that the bobbin vibrates in common with the swinging arm as a result of the formation of ridges and bulges on its circumference. Such vibrations, however, because of the beating effect in the back-oscillations of the bobbin and its impacts on the drive roller, are harmful to delicate thread material and are undesirable for the bobbin buildup. This is the case to an increased degree in winding devices in which the roller driving the winding body is also designed as a slit or groove drum for the traverse-motion thread guidance.

Because of these undesirable effects many diverse devices engaging on the swinging arm have been proposed as damping means. Mechanical, magnetic, and hydraulic devices have been tried for the damping of such vibrations. In this way it is possible, to be sure, to soften the beating effect, but not to nullify it completely, so that as before there still can result at the end of the winding process unround winding bodies of polygonal cross section.

It has been perceived, on the other hand, that the ridge and bulge formation in random winding is due to the synchromism of bobbin and thread guide, and provisions have been made, therefore, periodically to interrupt this synchronism. If besides the drive roller driving the bobbin there is provided a special drive for the thread guide, a differential gear has been engaged, for example, in one of these two drives so that the speed of the thread guide or the speed of the drive roller alternates, while the speed of the other part remains constant. Likewise, in the case of a roller driving the bobbin which roller serves simultaneously as the thread guide, the circumferential speed 'has been periodically changed by means of a regulating gear in such a way that between the bobbin and the drive roller there arises intermittently a greater speed dilference and slippage. Aside from the fact that such measures re quire a considerable expenditure, they are incapable of satisfying the higher demands, especially for the winding of freshly stretched chemical threads and the production of relatively large winding bodies, particularly with hard winding structure, because in these cases even slight ridge and bulge formations lead to vibrations of the spool (bobbin) and swinging arm, causing harmful and undesired beating effects.

It is an object of the present invention to provide a method and apparatus which overcomes the above de scribed problems in a simple and economical manner.

The invention uses a different approach, and in so doing proceeds from the insight that the ridge and bulge formation cannot be fully eliminated even with periodic disturbance of the synchronism of spool and thread guide, in consequence of the normal running during the intermediate time, and that one should oppose to it, therefore, as soon as it arises and any beating effect still occurring here should be prevented too.

In order to achieve this, it is proposed according to the invention, to damp the vibratory movements of swinging arm and spool occurring as soon as ridge or bulge formation commences, in both the direction of the path leading away from the drive roller and associated with the lifting off of the particular winding body circumference from the drive roller and in the other direction to restrain the part of the vibratory movement leading back to the drive roller, before the spool strikes against the drive roller, whereby the friction drive is interrupted. Through the damping or braking and stopping of the vibratory movements there is achieved a disturbance of the synchronism of spool and thread guide in the sense of an automatic regulation at the moment in which a ridge or bulge begins to form on the particular winding surface. The amplitudes of the vibratory movements here are still very small. After damping of the forward movement and stopping of the back movement, the winding body which is removed only fractions of a millimeter from the drive roller surface, turns freely, and in consequence of the idling or slip, undergoes a gradually diminishing circumferential speed until through continued distribution of the thread layers in traverse motion the winding diameter has grown so far that a steadily increasing and finally fully effective frictional contact is achieved.

The force with which the winding is pressed against the drive roller is increased by the contact pressure force which results from the damping or braking action on the swinging arm. On the other hand, it is Well known that for a satisfactory winding build-up it is desirable to diminish the contact pressure as the winding body circumference grows. It is further proposed, therefore, that the contact pressure of the damping or braking action on the swinging arm be progressively nullified as the winding body circumference increases. Likewise it is recommended that the contact pressure of the brake be discontinued altogether after formation of the full spool, in order to facilitate the moving out and change of the spool (bobbin).

In this manner, as the experiments confirm, it is possible not only to avoid the harmful and undersired impact of the winding body on the drive roller and to achieve a considerably smoother running of the spool driven by means of the drive roller, but also to lower considerably the tendency to form ridges or bulges in the random winding. Moreover, even hard-wound spool bodies of, for example, 2.5 million meters of wound chemical thread length and a weight of about 8 to 10 kg. can be produced with surprisingly uniform circular cross sec- 3 tion, whereby the thread run-off in the further processing is then uniform and damage to the thread quality avoided.

In order to carry out the measures described above a braking device is proposed according to the invention which consists esentially of a bow-like angle lever pivotally mounted on the end of the swinging arm carrying the spool. One arm of the lever which can be constructed as a brake block or can be equipped with a drag piece, engages a stationary curved braking path, preferably of trapezoidal cross section, with a given frictional effect load which results from the forces exertedon the second arm. Thus, for example, an adjustable and shiftable mechanically, hydraulically or similarly operating spanning (tension) means, can be arranged on the swinging arm which engages the second lever arm. The adjustable tension force is chosen in such a way that it suffices for the complete elimination of recoil.

In the case of hard winding formation, in order to control effectively and immediately the tendency of the winding to vibrate as a result of ridge and bulge formation, it is further proposed that the effective radius of the braking path be approximately the radius of the winding axis path or be greater than this.

In order to alter the amount of damping or braking over the particular winding process and/or to be able to move the braking arm out of the braking path at the end of the winding process, it is proposed, finally, that the loaded second lever arm be supported on a stationary control cam seated on or beside the swinging arm axis, which control cam changes the position of the angle lever as the swinging arm is moved out.

The subject invention can best be understood by referring to the illustrative embodiment set forth in the drawing, said drawing being a schematic side elevational view showing the device, which view is partly in section.

In the winding apparatus represented, swinging arm 1, which carries a spool holder 2 and spool 3, is swingably mounted on its stationarily borne axle 4 in the machine frame. Weight 6 adjustably placed on arm causes the spool surface to be pressed against driver roller 7. The slit or groove drum guide for the traverse motion of thread 8 is designated as 9. In the course of the winding process swinging arm 1, in consequence of the growing winding body circumference moves into the position 1 represented in dot-and-dash lines. For the spool change, the swinging arm is swung into the position 1" favorable for this purpose, in which the full spool 2" lies outside the working range of the adjacent pirning heads and, by operation of the chuck mechanism 10, is exchanged for an empty pirn tube.

According to the invention a bow-like angle lever is swingably borne on the end of swinging arm 1 carrying spool 3 by means of pin 11, one arm 12 of which lever engages with braking drag piece 13 the stationary, curved braking path 14 of trapezoidal cross section with frictional effect, while its other arm 15 is engaged by the tension device arranged in cartridge 16. The tension device consists essentially of pressure spring 17 with cap 18 and screw cover 19. Arm 15 is supported with its free end on control cam 20, mounted fixedly on the swinging arm axle 4. The angle levers 12, 15 can be guided by means of rail or cover 21.

Before the start of the winding process, the tension and damping spring 17 acting on the lever arm 15 is tensed by adjustment of screw cover 19 to such an extent that the other lever arm 12 with the brake block (drag piece) 13 is pressed on deflection of the weight-burdened swinging arm 1 into braking path 14. As a result of the contact pressure and of the friction of the drag piece on the braking path a completely or very nearly complete recoil blocking is achieved. Drag piece 13 may consist, for example, of a pressed paper composition and the braking path (track) of cast iron, in order to achieve a good frictional and braking effect.

The oncoming chemical thread 8, conducted in traverse motion by the slit or groove drum 9, is now wound in random winding'on spool 3 driven by drive roller 7. Instead of this arrangement, however, the spool (bobbin) can also be driven by friction from a roller which simultaneously serves as the thread guide. As soon as ridge or bulge formation occurs during the winding process on the winding body surface, it causes undesired vibrating movements of the swinging arm and spool which, however, by means of friction brakes 13, 14 are rendered harmless, inasmuch as each vibratory movement is first damped and in the swinging back caught up and stopped, before the spool strikes against the drive roller. Simultaneously, through the interruption associated with this of the frictional contact between the winding body and the drive roller the ridge or bulge formation is disturbed; for the spool now turns freely without the friction drive, with gradually decreasing speed until, through the thread layers further distributed in traverse motion the spool diameter has grown to such an extent that a constantly increasing and finally fully effective frictional contact on the drive roller is achieved. Such a temporary changing of speed in the turning of the spool while the thread guide speed remains constant is, according to experience, a condition which reduces the tendency to ridge, bulge in polygon formation.

During the winding process the free end of the tensed angle lever abuts with its arm 15 on stationary control cam 20, in which process it travels along the cam in accordance to the deflection of the swinging arm associated with the growing winding body circumference. Through the special design of cam 20 it is possible, if need be, to alter the contact pressure of the brake drag piece 13 on the brake path 14 and adapt it to the operating requirements of the winding body structure, for example, with a winding hardness diminishing gradually over the weight increase. It is also possible, however, as represented in the drawing, to arrange on the curve after the place which the lever arm 15 reaches at the end of the winding process a cam-like raised part which the lever arm 15 runs over in the moving out of swinging arm 1 to position 1", whereby the angle lever, after overcoming the pressure of tension spring 17, is deflected so far out that the braking drag piece 13 is swung out of brake path 14. The brake path 14, therefore, can be limited in its length to the actual working path of the layer thickness of the winding build-up.

The proposed arrangement can be regarded as maintenance-free, for any possible wear on the brake drag piece can be compensated by sliding the same on the bowlike arm 12.

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

The invention is hereby claimed as follows:

1. A process for winding endless threads in random winding on spools which are rotatably carried on a swinging arm and are driven by a drive roller which comprises: absorbing the vibratory movements of the swinging arm and spool by damping the movement of said swinging arm and spool, resulting from the formation of ridges and bulges on the surface of the winding body, away from said drive roller and further increasing the period during which the surface of the winding body is out of contact with the surface of said drive roller by braking the movement of the winding body surface back toward the drive roller.

2. Apparatus for forming a random winding of endless thread which comprises: a swingable arm; a rotatable spool mounted on said swingable arm; a drive roller in contact with said spool; and a braking device pivotally mounted on said swinging arm, said braking device including an angle lever having two arms, a stationary braking path having a friction producing surface, one arm of 5 said lever engaging said friction producing surface, a tension producing means associated with the other arm of said lever, said tension producing means urging one arm into frictional engagement with the friction producing surface of said braking path.

3. Braking apparatus as in claim 2, wherein the arm of said lever engaging said braking path includes a drag piece.

4. Braking apparatus as in claim 2 wherein the elfective radius of the braking path is at least equal to the radius of the spool axis path.

5. Braking apparatus as in claim 2 wherein one end of the lever is in contact with a control cam associated with the axle of the swinging arm, said cam being arranged to cause a change in the position of the angle lever as the swinging arm rotates.

6. In the process of claim 1, decreasing the braking action on the swinging arm as the winding body grows in circumference.

References Cited UNITED STATES PATENTS 1,799,153 4/ 193-1 Brink 242l8 2,165,018 7/1939 Taylor 24218 2,243,678 5/ 1941 McKean 242-18 2,594,509 -4/ 1952 Stahl 2A2 18 2,605,974- 8/ 1952 Keith 242-18 2,677,506 5/ 195 4 Moos 242-48 2,752,100 6/ 195 6 Stange 242-18 FOREIGN PATENTS 530,856 12/ 1940 Great Britain.

STANLEY N. GIL-REAT H, Primary Examiner.

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