Textiles: spinning – twisting – and twining – Apparatus and processes – Threading up
Reexamination Certificate
2002-01-17
2002-12-17
Calvert, John J. (Department: 3765)
Textiles: spinning, twisting, and twining
Apparatus and processes
Threading up
C057S279000, C057S352000
Reexamination Certificate
active
06494029
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a yarn texturing machine of the type disclosed in WO 98/33963 and corresponding U.S. Pat. No. 6,209,302.
In the known texturing machine, a plurality of feed yarn packages are arranged in a creel frame, one on top of the other. Each feed yarn package supplies a yarn to a processing station in the machine. For unwinding and for advancing and possibly drawing the yarns, a plurality of feed systems are arranged in the machine, one after another. In this arrangement, the first feed system is arranged above the creel frame to withdraw the yarn from the feed yarn package and to advance it into a false twist texturing zone. This arrangement permits advancing the yarn without deflection from the feed system directly to a heating device within the false twist texturing zone. However, at the beginning of the process, it is necessary that for threading the yarn, the feed system be moved from its operating position to a servicing position. To this end, the feed system is mounted on a slide, which can be moved by means of a linear drive along a guide rail. In so doing, it is necessary to overcome considerable differences of height between the upper operating position and the lower servicing position. This requires a transfer of a large force for the movement of the slide with the feed system. Furthermore, it is necessary that the feed system be very accurately positioned in its operating position, so that the advance of the yarn in the downstream heating device can take a desired course for the treatment of the yarn.
Furthermore, the two feed systems may be driven at a speed difference, with the first feed system being operated at a lower speed in relation to the second feed system. In the known texturing machine, the feed system upstream of the texturing zone is designed and constructed as a feed roll, which advances the yarn by friction, substantially without slip, in a track extending on its circumference. To apply to the yarn the frictional force needed for the advance, it is necessary to have a minimum looping on the circumference of the feed roll as well as a yarn track for a transverse deflection of the yarn in the looping region. However, such a design and construction of the feed system requires in a first threading of the yarn, a minimum yarn tension for inserting the yarn into the track of the feed roll. Furthermore, the speed difference between the adjacent feed systems, as well as the friction exerted by the feed roll on the yarn during its threading lead to substantial differences in the yarn tension. However, the threading of the yarn, during which the speeds of the feed systems are varied, is possible only to a limited extent, when the drives of the feed systems of adjacent processing stations are coupled.
It is therefore an object of the invention to further develop the texturing machine of the initially described kind such that an operator can perform the vertical adjustment of the feed system and the threading of the yarn without significant physical effort. Furthermore, it is the object of the invention to create a texturing machine, wherein upon reaching the operating position of the feed system, the yarn can be gently threaded in a processing station of the texturing machine despite speed differences in the feed systems and without significant changes in the yarn tension, and wherein it can be gently inserted into the heating device.
SUMMARY OF THE INVENTION
The above and other objects and advantages of the present invention are achieved by the provision of a yarn texturing machine which comprises a plurality of serially arranged yarn feed systems. At least one of the feed systems comprises a driven feed roll which is partially looped by the advancing yarn so as to advance the yarn by friction in a guide track on the feed roll. A guide member is mounted for movement relative to the feed roll so as to vary the extent of the looping between a threading position and an operating position. In the threading position, the yarn does not contact the feed roll, and in the operating position the yarn is in contact with the feed roll.
The one yarn feed system may also comprise a slide which is displaceable along a guide rail between a servicing position and an operating position. The slide is guided along the guide rail by means of a slide element which slideably engages the guide rail. Also, a drive is coupled to the slide or the slide element via a connecting means, so as to move the slide between the two positions.
The texturing machine of the present invention distinguishes itself in that irrespective of its positions, the feed system can be guided along the guide rail with a uniform stability. The yarn may advance in the feed system already in the servicing position, since the transverse forces that are transmitted by the yarn to the feed system, are safely absorbed by the guided slide, when the feed system is moved.
The connecting means between the drive and the slide element is designed and constructed such that until the operating position is reached, it ensures a reliable guidance of the slide element in the guide rail, and a transfer of force for a uniform movement.
In a particularly advantageous further development of the invention, the connecting means is formed by a magnetic piston, which is guided in a cylinder by means of compressed air, and which connects to the slide element by magnetic forces. The direct connection between the slide element and the piston controlled by the drive makes it possible to position the slide and thus the feed system in a very accurately reproducible manner, which stabilizes the yarn advance in the operating position.
The combination of a cable line and the drive allows large weights and long distances to be handled in an advantageous manner. To this end, the slide element guides the slide with the feed system along the guide rail. The drive is preferably connected to the slide element, via a cable line, which extends along the guide rail. Thus upon actuation of the drive, only one force acts upon the slide element in the direction of movement. The force is transmitted by the cable line, thereby eliminating disturbance variables by transverse forces. Preferably, the drive is formed by a piston-cylinder unit, wherein the piston in the cylinder is controlled by compressed air. With that, it is possible to move the feed system fast and precisely between the lower servicing position and the operating position. However, it is also possible to hold the feed system in an desired position between the servicing and the operating position. Such a holding position can be realized by applying pressure to both sides of the piston within the cylinder.
To enable a sensitive control of the movement of the slide, the cable line may comprise two cables, which are connected to the opposite ends of the slide element, and guided to the cylinder respectively over an upper and a lower pulley. The cylinder extends parallel to the guide rail, so that the cables each extend into the cylinder through an inlet provided at each end of the cylinder, and connect to the opposite ends of the piston.
To avoid major pressure losses while controlling the cylinder, it is proposed to arrange a seal in each inlet of the cylinder, through which the cable extends.
According to one specific embodiment, a control valve is used for controlling the piston-cylinder unit. The control valve is designed and constructed such that the piston is controllable both in its direction and in its speed, so that the movement of the slide element is variable in its direction of displacement and in its speed of displacement. This development is especially of advantage for moving the feed system into its operating position. In this connection, it is possible to reduce the speed of displacement shortly before reaching the operating position, so that a slow and, thus, safe entry into the operating position is possible. This is especially advantageous for inserting the yarn into the heating device. In such texturing machines, it is preferred to us
Berges Dietrich
Jaschke Klemens
Schulz Andreas
Barmag AG
Calvert John J.
Hurley Shaun R
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