EP-4741547-A1 - SYNCHRONIZATION SYSTEM FOR ROVING FRAMES

EP4741547A1EP 4741547 A1EP4741547 A1EP 4741547A1EP-4741547-A1

Abstract

The invention relates to a synchronization system for fiber stretching devices of roving frames, of the type having the drive section only at one end. The synchronization system is configured to be coupled to the non-driving section of at least one motorized cylinder thereby reducing and/or cancelling out the lag or lead torsions generated by the natural forces and frictions of long fiber stretching devices during acceleration or deceleration, or due to variations in relative speed between the cylinders during normal operation.

Inventors

ROVIRA TRIAS, JUAN
VERDAGUER ROSELL, Albert

Assignees

Electro-Jet, S.L.

Dates

Publication Date: 20260513
Application Date: 20251010

Claims (16)

A synchronization system for a stretching device of the type comprising at least two motorized cylinders arranged in parallel in fixed positions and wherein the drive section for actuating the at least two motorized cylinders is arranged only at one of the two ends of the stretching device, wherein the system is configured to be coupled to the other non-motorized end of the stretching device, the system comprising: a shaft per cylinder configured to be coupled to the non-motorized end of the cylinder and rotate integrally with it, and wherein the shaft is configured with a pulley; and a transmission belt configured to connect two pulleys corresponding to two shafts in such a manner that traction is transmitted between the corresponding cylinders.
The system of claim 1, wherein both the pulleys and the belt are configured with complementary coupling means, for example, they are toothed so that the teeth connect in an interleaved manner.
The system of claim 2, wherein the first pulley is configured on the shaft coupled to the cylinder subject to less torsion, and wherein the second pulley is configured on the shaft coupled to the cylinder subject to more torsion, wherein the first pulley is fixed and configured to rotate together with and in the same direction as its corresponding shaft, while the second pulley is unidirectional and arranged in such a way that it allows the pulley to rotate freely in one direction only.
The system of claim 3, wherein, in the case where the first pulley is located upstream of the second pulley, the free rotation direction of the second unidirectional pulley is opposite to the drive direction of the first pulley, and wherein, in the case where the first pulley is located downstream of the second pulley, the free rotation direction of the second unidirectional pulley is the same as the drive direction of the first pulley.
The system of claim 1, further comprising a third motorized cylinder arranged in parallel in a fixed position on the other side of the second cylinder in relation to the first cylinder, the system further comprising a third shaft configured to engage with the non-motorized end of the third cylinder and rotate integrally with it, and wherein the third shaft is configured with a third pulley, wherein the second shaft further comprises a fourth pulley, and wherein the system further comprises a second transmission belt configured to connect the third and fourth pulleys corresponding to the third and second shafts, respectively, such that traction is transmitted between the corresponding cylinders, wherein the third pulley is configured on the third shaft coupled to the cylinder subject to less torsion and wherein the fourth pulley is configured on the second shaft coupled to the cylinder subject to more torsion, wherein the third pulley is fixed and configured to rotate together with and in the same direction as its corresponding shaft, while the fourth pulley is unidirectional and arranged in such a way that the pulley is allowed to rotate in one direction only, but not in the opposite direction.
The system of claim 5, wherein the free rotation direction of the fourth pulley is opposite to the drive direction of the third pulley.
The system of claim 1, further comprising at least one tensor module configured to adequately tension the belt based on the spacing between cylinders, wherein the at least one tensor module is configured to engage the first shaft of the first cylinder and/or the third shaft of the third cylinder.
The system of claim 7, wherein the at least one tensor module comprises at least one vertical arm, wherein the upper part of the vertical arm comprises a free-rotating roller arranged on the inside of the belt and on which the belt rests when rotating between the two pulleys, wherein the at least one tensor module additionally comprises a main shaft to which the vertical arm is coupled, the main shaft being attached to the stretching device in such a way as to allow the free-rotating roller to move transversely to the stretching device, allowing the belt to be stretched appropriately depending on the spacing between cylinders; or wherein the at least one tensor module comprises two vertical arms, one corresponding to the first cylinder and the other to the third cylinder, allowing both belts to be adequately tensioned depending on the spacing between cylinders.
A synchronization method for a stretching device of claim 1, of the type comprising at least two motorized cylinders arranged in parallel in fixed positions and wherein the drive section for actuating the at least two motorized cylinders is arranged only at one of the two ends of the stretching device, wherein the system is configured to couple to the other non-motorized end of the stretching device, the method comprising: coupling, per cylinder, a shaft and a pulley that rotates together with the shaft to the non-motorized end of the cylinder; and connecting two pulleys corresponding to two shafts with a transmission belt and transmitting traction between the corresponding cylinders.
The method of claim 9, wherein a first pulley is fixed and rotates together with and in the same direction as its corresponding shaft, while a second pulley is unidirectional and rotates freely in one direction only, wherein the first pulley is configured on the shaft coupled to the cylinder subject to less torsion, and wherein the second pulley is configured on the shaft coupled to the cylinder subject to more torsion.
The method of claim 10, wherein, in the case where the first pulley is located upstream of the second pulley, the free rotation direction of the second unidirectional pulley is opposite to the drive direction of the first pulley, and in the case where the first pulley is located downstream of the second pulley, the free rotation direction of the second unidirectional pulley is the same as the drive direction of the first pulley.
The method of claim 9, further comprising coupling a third motorized cylinder in parallel in a fixed position on the other side of the second cylinder in relation to the first cylinder, further comprising coupling a third shaft and a pulley to the non-motorized end of the third cylinder that rotate integrally with the shaft, and wherein the third shaft is configured with a third pulley, wherein the second shaft further comprises a fourth pulley, and wherein the method further comprises connecting the third and fourth pulleys corresponding to the third and second shafts, respectively, by means of a second transmission belt such that traction is transmitted between the corresponding cylinders, comprising coupling the third pulley onto the third shaft coupled to the cylinder subject to less torsion and coupling the fourth pulley onto the second shaft coupled to the cylinder subject to more torsion, wherein the third pulley is fixed and rotates together with and in the same direction as its corresponding shaft, while the fourth pulley is unidirectional and rotates in one direction only, but not in the opposite direction.
The method of claim 12, in which the fourth pulley rotates in a free rotation direction opposite to the drive direction of the third pulley.
The method of claim 9, further comprising adequately tensioning the belt depending on the spacing between cylinders by at least one tensor module, wherein the at least one tensor module is coupled to the first shaft of the first cylinder and/or to the third shaft of the third cylinder.
The method of claim 14, wherein the belt is supported between the two pulleys on a free-rotating roller located on the inside of the belt and on which at least one vertical arm is supported, and moving the free-rotating roller transversely to the tensor device, allowing the belt to be tensioned appropriately depending on the spacing between cylinders; or comprising tensioning both belts as a function of the spacing between cylinders using two vertical arms of the at least one tensor module, one corresponding to the first cylinder and the other to the third cylinder.
A fiber stretching device, such as of a roving frame, comprising at least one synchronization system according to the claim 1.

Description

TECHNICAL FIELD The invention relates generally to the field of textile industries, and more specifically, to a synchronization system for a fiber stretching device, or system, of roving frames. BACKGROUND ART FIG. 1 shows, by way of example, a fiber stretching device 100 for roving frames (also known as a drafting system) comprising, in this case, three motorized cylinders arranged in parallel in fixed positions and covering practically the entire length of the roving frame, and a plurality of presser arms perpendicular to the motorized cylinders, distributed along the roving frame, and provided with free-rotating rollers arranged in parallel with said motorized cylinders. The presser arms have first rollers and second free-rotating rollers, located parallel to and above the motorized cylinders, for pressing the fibers to be stretched. The pressure exerted on the fibers and their driving at increasing speed in the direction of travel (downstream, as indicated by the arrow) causes the fibers to stretch before being twisted and wound onto spindles. The drive section 140 is located at the beginning of the roving frame (in this case, on the left of the figure) and comprises at least one electronically controlled motor to vary the rotation speed of each cylinder. Due to the characteristics of such drafting frames, such as different cylinder diameters, the distance between cylinders, or the desired degree of stretching, the cylinders rotate at different speeds. In regular operation, the cylinders are started at the same time, i.e., synchronously, and then accelerated to their respective operating speeds, where they maintain synchronization (albeit at different speeds). The cylinders are typically arranged to rotate at different speeds. In a typical configuration, the third cylinder 130, further upstream, rotates more slowly than the second cylinder 120, and its function is to collect the fiber from the previous device and feed it into the drafting system. Therefore, in this context, the third cylinder 130 is referred to as the input cylinder. In turn, the second cylinder 120, in the middle, rotates more slowly than the first cylinder 110. Consequently, the first cylinder 110 rotates faster than the second 120 and third 130 cylinders. Due to its dimensions and those of its rollers, the second cylinder generates resistance to the movement of the fiber. Therefore, in this context, the second cylinder 120 is called the stretching cylinder. The first cylinder 110, further downstream, rotates the fastest and, together with the second cylinder, generates the stretch and drives the stretched fiber for collection on the spindles (not shown). Therefore, in this context, the first cylinder 110 is called the exit cylinder. The starting material for the entire process is fibers made up of a plurality of thick fiber sections, for example, a mixture of cotton and plastic, which when stretched together form a thinner yarn. However, during this stretching process, the fiber can easily fray, even with the application of very light longitudinal force, as it is a highly delicate material. To prevent fraying, the fiber is twisted around itself, making it resistant to breakage along its main axis, resulting in a strong yarn. However, the more twisted the fiber is, and the more resistant it is to breakage, the more difficult and resistant it is to stretching. For this reason, the yarn manufacturing process is carried out in stages. In an initial stage, the base material, that is, the unstretched fiber, which is usually wider than the desired final yarn width, is stretched to the required extent. In a later stage, the stretched yarn is twisted and other post-processing steps are applied to finish manufacturing the strong yarn. The degree of stretching depends both on the properties of the starting fiber and on the function or application of the final yarn, together with the post-processing steps according to the intended use. The speed and rotational power of the motorized cylinders are carefully controlled, as otherwise this can result in excessive stretching of the fibers or even their breakage. This undesirable effect is heightened the more delicate the fiber being treated is, as the intrinsic strength of a fiber depends on its starting material. For this reason, stretching devices have a limited length, as it is difficult to precisely control the forces applied between the pressing arms, rollers, intermediate fibers, motors, and long cylinders of the drafting frame. However, to produce a more efficient, higher-performance roving frame, it is desirable for the stretching device to be as long as possible, in order to incorporate the maximum number of stretching assemblies (presser arms and rollers) to stretch as many fibers as possible. Typically, existing long roving frames can reach approximately 50 meters in length and comprise cylinders of similar length. In the future, it may be possible to increase this length even further. In