DE2106480A1 - Method and device for the continuous stretching of heated thermoplastic material - Google Patents

Description

Bag. 720

Method and device for continuous Stretching of heated thermoplastic material.

B a r m a g

Barmer Maschinenfabrik Aktiengesellschaft

Wuppertal

The invention relates to a process for the continuous stretching of heated thermoplastic material, such as 2.B. Threads, ribbons and the like., Containing stretching devices Machines such as B. Spinndraw-, Streckspul-, Streckzwirnoder Texturing stretching machines with a certain stretching ratio. The invention also relates to stretching devices with at least one heating device for carrying out the method.

In the process engineering of thermoplastics, the stretching process is one of the most important process steps. It mainly serves to change the molecular structure of the thermoplastic material. During stretching, the thermoplastic material is subjected to a change in length, in many cases with the simultaneous supply of heat. The stretching device consists of feed organs (eg rollers, godets or the like) and discharge organs (eg rollers, godets and the like), which are operated from the feed organs at a higher peripheral speed. Heated cylinders, heated godets, heating plates or similar are used as heating devices. for use. The material, especially threads, are stretched to a multiple of the original length. The stretching ratio is equal to the

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ratio of the feed speed to the discharge speed. Every change in the ratio of these speeds leads to a change in the nature of the goods. Hence the Stretching devices usually operated so that the ratio between feed speed and discharge speed remains constant during a winding cycle.

With a constant draw ratio, however, some of them are produced special operating phases of the machine difficulties. So when starting up there is a risk that it will be under full voltage Material standing in the stretching zone tears on the heating units as a result of the initial pressure or as a result of embrittlement. At the Run-out must be avoided that the material comes to a standstill under excessive tension. Because there is a risk that that Is stretched more than desired, tears, becomes brittle or undergoes other disadvantageous changes. Is at a standstill the harmful influence of the heating device on the stationary material on the level of the prevailing mechanical tensile load addicted.

The object of the invention is to avoid the disadvantages of conventional Vers stretching processes and stretching devices for thermoplastic material, which arise from the fact that the stretching ratio cannot be adapted to the particular operating phases. There is therefore a method for the continuous stretching of heated thermoplastic material, such as. B. threads, tapes and the like., Provided, which is characterized in that the stretching ratio for special operating phases of the stretching devices containing machines such. B. run-out and start-up, is switched to another predetermined value. This value is obtained taking into account the speed and the temperatures of the goods or the heating devices in contact with the goods and, in particular,

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special the conditions that he on the one hand as mechanical stress endured by the property during the particular operating phase and that on the other hand it leads to such a reduction in the susceptibility of the goods to temperature that temperature damage can be avoided. So it can be beneficial if necessary be e.g. B. for start-up and / or shutdown to a lower draw ratio to switch to reduce the thread stress during these operating phases.

Now, although machines with stretching devices are known that are equipped in such a way that the stretching ratio can also be controlled during operation, be it to determine the optimum Stretching ratios {z. B. DAS 1 ool 333.), be it for control and control of the draw ratio (e.g., U.S. Patent 2,361,217). However, these machines are designed to solve the specified tasks and not useful for carrying out the method according to the invention.

In contrast to the state of the art, a stretching device is used with at least one heating device for the continuous stretching of thermoplastic material, such as threads, tapes and the like., which is characterized in that the draw ratio manually or automatically on one preselectable other value, preferably when starting and / or stopping the stretching device can be switched.

The change required to change the draw ratio the speed ratio between the feed and discharge elements can be adjusted via stepwise or steplessly switchable gears take place. The preselection and switching of a different stretching ratio is then carried out according to the invention by preselection and Execution of a certain switching process, e.g. B. Filing certain Clutches or adjustment of the continuously variable transmission by a preselected adjustment path.

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However, the serviceability of the stretching device is facilitated and the reproducibility of those determined to be optimal Stretching ratios increased when, in an advantageous embodiment of the invention, the feed members with the Discharge organs Via a main gear as well as a switchable or continuously adjustable one arranged parallel to this Kebengetrieba are in connection, the main gearbox and the auxiliary transmission can be switched on as required.

In this version, the change in the stretching ratio Required change in the speed ratio between the feed and discharge elements by changing the Speed ratio between the drive motor and feed organs or between the drive motor and discharge organs or this both speed ratios take place.

For a further embodiment of the invention, it is therefore proposed that that the discharge organs with the main transmission via an insertable clutch and with the secondary transmission via a Overrunning clutch are in connection, or that the feed members with the main transmission via a insertable clutch and are connected to the auxiliary transmission via an overrunning clutch, or that the feed organs and discharge organs with the main gear are connected via clutches that can be inserted at the same time and with the auxiliary transmission via overrunning clutches, wherein the main gear and the auxiliary gear can each be driven by a drive motor.

A change in the speed of either the feed organs or the discharge organs or both organs can be achieved by means of a Carry out a device in which the supply and discharge elements are each driven by a motor, preferably with a frequency-dependent motor Speed are driven, wobai the Drehjeahlverkältnie

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Motors can be preselected and adjusted via a control unit.

According to another embodiment of the invention, the supply and removal organs are available via a main gear as well as a Epicyclic gear in connection, with one of the sun gears or the web of the epicyclic gear via a braking device braked and preferably via a speed controllable Motor can preferably be driven in both directions at a preselectable speed.

In the following the invention with reference to Figures 1 to described. The figures represent schematic sketches. It show

Fig. 1 to 4 stretching devices according to claims 3 to 6,

Fig. 5 a stretching device according to claim 7, Fig. 6 a stretching device according to claim 8.

The material, for example the thread 10, is fed to the stretching device via the feed element 8 and removed again with the discharge element. The peripheral speed of the discharge element 9 is higher than that of the feed element 8 during the stretching process. The feed and discharge elements can be designed as rollers, godets or similar devices. In the stretching zone between the supply and discharge elements there is at least one heating device 21 and / or the delivery element 8 is heated. The temperature of the heated supply elements or the heating devices are regulated to a certain value and adjusted so that the material has the desired properties.

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The stretching ratio permanently set in conventional processes in stretching devices, hereinafter referred to as the main stretching ratio referred to, is by means of the main drive motor 5 via the main transmission 1 (Fig. 1, 2, 3, 4, 6) manufactured.

So far, this main draw ratio has been maintained in every operating phase, with damage to the goods due to mechanical and temperature stress in particular Phases of the stretching process could not be avoided. One Temporary mechanical relief of the goods by changing the stretching ratio alone did not bring about any remedy, since the time-temperature behavior of thermoplastics, such as lin. Polyester, depends on the draw ratio. So can a thread stretched in a certain ratio remains at a certain temperature for a longer period of time without significant damage endure, for example, as a thread that is not stretched at all.

According to the invention, for special operating phases that differ from the main operating phase in particular by another Differentiate between the feed and / or removal speed of the good, a draw ratio that deviates from the main draw ratio is determined, for example, by experiment. It is This Vers trecking ratio to optimize especially so that it is bearable as a mechanical load, and that it leads to such a reduction in the 2eit temperature susceptibility of the goods, as taking into account the occurring Temperatures and the contact or dwell times of the goods on the heating devices is required.

In FIGS. 1, 2, 3, 4, such a stretching ratio can be used for special operating phases, such as the run-down and start-up phases, can be made using a lifting gear. The coupling

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the main or auxiliary transmission can »as shown in Fig. 1, take place via two switchable clutches or in any other way. You can also absr, as in FIGS. 2 and 3, take place via a switchable clutch 3 and an overrunning clutch 4.

This has advantages in terms of operation. If the switchable clutch 3 is engaged, the feed and Discharge organs driven via the main transmission 1 with the main speed ratio. The lifting gear 2 also runs idle. Only when the clutch 3 is disengaged does the overrunning clutch take effect and establish the speed ratio between the supply and discharge organs takes place via the previously to a certain transmission ratio Set auxiliary gear 4.

The clutches 3 and 4 can either be between the gearboxes

1 and 2 and the feed members 5 (Fig. 3) or between the Geared and the discharge organs 9 (Fig. 2) be arranged. It depends on the arrangement of the clutches whether the feed organs or the discharge organs have the greater accelerations or experience delays.

In the device according to FIG. 4, the stretching device can be driven in special operating phases via a second motor 6, which can be designed to be smaller than the main drive motor 5 and / or can have a different speed. To switch over the stretching ratio, the clutches 3 ¹ and 3 ″ are actuated. As a result, the engine 6 and the auxiliary transmission pass through the overrunning clutches 4 * and 4 ″

2 with the gear ratio set on it between the supply organs and the discharge organs to the effect.

The device according to FIG. 5 consists of a rotation controllable each Motor 11 and 12 for the feed and discharge

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organs 8 and 9. Synchronous motors are particularly suitable for this purpose, whose speed can be controlled via the frequency of the feed current. Frequency generators serve as the energy source, the output frequencies of which can be set and preselected via a control device.

In the device according to FIG. 6, in series with the main transmission 1, which is driven by means of the main drive 5 is switched, a planetary gear 14. The web 17 or one of the sun gears 15 or 16 of this Ural impeller transmission can optionally be driven by the motor 19, the speed of which can be preselected in both directions, or by means of the braking device 2o be braked. This means that the output speed of the planetary gear can be switched to preselectable values. The epicyclic gear 14 can, unlike in Fig. 6, can also be arranged between the main gear 1 and the feed members 8 or parallel to the main gear 1.

It can be advantageous to use the stretching devices according to the invention to automate at least partially, since they have advantageous conditions for this. As an example, consider the possibility mentioned, the switching of the stretching device to a different stretching ratio automatically via the signal for Change the operating phase (shutdown, start-up, etc.). When the invention is applied to draw twisting machines it also appears expedient to switch from the main stretch ratio to the other stretch ratio or, conversely, to change the position of the ring rail movement with a suitable phase shift in order to prevent it from being different stretched goods are wrapped on a cop.

The advantage of the invention is that it allows the dependence between the stretching ratios and the

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Time-temperature ~ tensile ~ behavior of the thermoplastics, such as 2. B. with polyethylene terephthalate , also to be taken into account in special operating phases of the stretching process. It enables easy switching from one main stretching ratio to another defined stretching ratio, which can be reproduced as often as desired, in order to achieve optimal operating conditions in all phases of the stretching process. This avoids thread breaks / temperature or other damage to the goods with the consequence of production interruptions or the production of inferior goods.

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Claims (8)

- Io - bag. 72o Claims fl) j Process for the continuous stretching of heated thermoplastic goods, such as. B. threads, tapes and the like., with machines containing stretching devices, such as B. spin-draw, draw-bobbin, draw-twist or texturing machines, with a certain draw ratio, characterized in that the draw ratio for special Operating phases of the machines, such as B. run-out and start-up, is switched to another predetermined value. 2) stretching device with at least one heating device for performing the method according to claim 1, characterized in that that the draw ratio can be switched manually or automatically to a preselectable other value. 3) stretching device according to claim 2, characterized in that the feed members (8) with the discharge members (9) over a main gear (1) as well as a switchable or continuously adjustable secondary gear arranged parallel to this (2) are in connection, the main transmission (1) and the auxiliary transmission (2) being selectively switchable. 4) stretching device according to claim 3, characterized in that the discharge members (9) with the main gear (1) over an insertable clutch (3) and with the auxiliary gear (2) • are connected via an overrunning clutch (A) (especially Fig. 2). - 11 - 209837/0919 - 11 - Bag. 72o 5) stretching device according to claim 3, characterized in that that the feed members (8) with the main gear (1) via an insertable coupling (3) and with the secondary gear (2) are connected via an overrunning clutch (4) (in particular Fig. 3). 6) stretching device according to claim 3, characterized in that the feed and discharge elements (8, 9) with the main gear (1) via simultaneously insertable clutches (3 ¹ , 3 ") and with the secondary gear (2) via overrunning clutches (4 ¹ , 4 ") are in connection, the main gear (1) and the secondary gear (2) each being drivable by a drive motor (5 or 6) (in particular FIG. 4). 7) stretching device according to claim 2, characterized in that the feed and discharge elements (8, 9) can be driven by a motor (11, 12) each with a preferably frequency-dependent speed, the speed ratio of the motors (11, 12) via a control unit (13) is preselectable and adjustable (in particular Fig. 5). 8) stretching device according to claim 2, characterized in that the supply and discharge elements (8, 9) are connected via a main gear (1) and an epicyclic gear (14), with one.der sun gears (15 or 16) or the Web (17) of the epicyclic gear can be braked via a braking device (2o) and preferably driven in both directions at a preselectable speed via a speed-controllable motor (19) (in particular FIG. 6). 209837/0919 Lee rs ei τ e