Abstract: A process and an arrangement for re-starting a previously interrupted spinning process in a spinning arrangement is provided. The arrangement includes a drafting unit which can be shut down and also an airjet unit including a vacuum chamber. For the purpose of removing an initially inhomogeneous fiber stream, a staple fiber strand, delivered by the re-operating drafting unit, is temporarily suctioned as waste via a deflecting device after it has left the drafting unit. Only then, when a homogeneous fiber stream has formed, is the staple fiber strand joined with a thread which is transported through the airjet unit. The inhomogeneous fiber stream is removed with the aid of the low pressure in the vacuum chamber.

Abstract: A holding device for a twin pressure roller of a drafting unit includes a number of bottom rollers. The twin pressure roller includes a stationary axle and two rotatably supported upper rollers. The holding device includes at least one positioning element assigned to the axle of the twin pressure roller and at least one force transmission element, wherein the positioning element is arranged in the area of the center of the axle of the twin pressure roller and thus permits the twin pressure roller to move in a pendulum fashion around the center. The holding device, together with the twin pressure roller may be lifted from the bottom roller. At least one catch bearing for approximate positioning during placement on the bottom rollers is assigned to the twin pressure roller. It may further be provided that the force transmission element is arranged separately from the positioning element and that the catch bearing is integrated into the force transmission element.

Abstract: A twin unit has two drafting devices for drafting fiber strands and is applicable in a spinning machine. The twin unit includes a common housing for the two drivable drafting devices, whereby the housing is detachably mounted in a machine frame. The drafting devices include a number of drivable bottom rollers and are arranged essentially mirror-symmetrical to one another. Each bottom roller has an area which drafts the fiber strand and is characterized in that the bottom roller has two bearing points. The two bearing points of each bottom roller are arranged one on either side of the area which drafts the fiber strand. In one variation, at least two opposite bottom rollers may form a bottom roller pair, in which the bearing points facing to the plane of symmetry of the twin unit are taken up in a joint bearing take-up. In addition, a top roller in the form of a twin pressure roller may be assigned to a bottom roller pair.

Abstract: An arrangement for manufacturing a spun thread from a staple fiber mass includes a feed channel having an outlet opening for feeding the fiber mass, and a yarn withdrawal channel having an inlet opening. In order to generate a rotating current around the entry opening of the yarn withdrawal channel, a vortex chamber is provided with compressed air nozzles. An air evacuation duct surrounds, essentially ring-like, a stationary, spindle-shaped component which forms the yarn withdrawal channel. The feed channel extends in a meandering manner and includes fiber guiding surfaces, which are designed in the form of deflecting edges, between which the staple fiber mass is without support.

Abstract: A yarn withdrawal device for open-end spinning arrangements has a yarn withdrawal nozzle and a balloon-breaking insert which extends the axial channel of the yarn withdrawal nozzle. The yarn withdrawal nozzle has a curved contact surface for deflecting a yarn to be withdrawn and simultaneously rotating the yarn in a crank-like manner, which contact surface graduates from a front surface into the axial channel. The balloon-breaking insert has an inner wall which is provided with raised areas and/or recesses, with which the yarn comes into contact. The contact surface of the yarn withdrawal nozzle is a smooth steel surface. The raised areas and/or the recesses of the balloon breaking insert are such that a yarn hairiness in the range of 3 mm in length is achievable. In addition, values in relation to the spinning stability, tear resistance and evenness can be achieved which are usual in the case of a notched contact surface of standard yarn withdrawal nozzles without a balloon-breaking insert.

Abstract: A double-apron drafting unit for spinning machines has a delivery roller pair and an apron pair arranged upstream therefrom. The apron pair guides a fiber strand in the area of a delivery nipping line, with which it forms a wedge-shaped gap. Devices are provided for keeping air currents, which circulate with the delivery roller pair, away from the area of the delivery nipping line, which devices are located outside of the wedge-shaped gap point formed by the delivery nipping line and the apron pair. The devices are, however, located in direct proximity to the delivery roller pair and the apron pair.

Abstract: An arrangement for manufacturing a spun thread from a staple fiber mass includes a feed channel having an outlet opening for feeding the fiber mass, and a yarn withdrawal channel having an inlet opening. In order to generate a rotating current around the entry opening of the yarn withdrawal channel, a vortex chamber is provided with compressed air nozzles. An air evacuation duct surrounds, essentially ring-like, a stationary, spindle-shaped component which forms the yarn withdrawal channel. The feed channel extends in a meandering manner and includes fiber guiding surfaces, which are designed in the form of deflecting edges, between which the staple fiber mass is without support.

Abstract: The invention concerns a cleaning apparatus for the cleaning of a spin rotor of a spinning station leaning head which can be insertably presented to the spin rotor and on which cleaning head are placed at least two scraper elements. In accord with the invention, the at least two scraper elements are pneumatically extendable, wherein the position of the two scraper elements are so secured on the outer circumference of the cleaning head, that the sum of the contact forces which are exerted from the scraper element in the radial direction onto the rotor is zero, or practically zero.

Abstract: An arrangement for sealing an opening of a rotor housing in which a vacuum prevails, through which opening a shaft of a spinning rotor, supported outside of the rotor housing, projects. The arrangement has free floating sealing element arranged towards the opening and forming at least two sealing gaps with the spinning rotor. A first sealing gap is located between the sealing element and the shaft, a second sealing gap is located between the sealing element and a collar of the spinning rotor which borders the shaft. The sealing element can form an additional third sealing element with the back wall of the spinning rotor.

Abstract: An arrangement for an open-end rotor spinning comprises a spinning rotor which is radially supported with a rotatable shaft in a wedge-shaped gap of two supporting disc pairs and axially in a step bearing housing. The shaft can be pulled out from its support from the operator's side of the arrangement and inserted again into the support. For the purpose of cleaning the gap between the back supporting disc pair and the front face side of the step bearing housing, a tube is provided having an entry opening at the operator's side of the arrangement and leading to the area of the step bearing housing and aligned against the shaft with an opening.

Abstract: In an arrangement for application in open-end rotor spinning, an opening roller is housed in a swivel housing. The swivel housing can, together with the assembled opening roller, be removed from the arrangement for open-end rotor spinning when the machine is in operation. The opening roller, due to its mass, continues to rotate after it has been separated from the tangential belt which drives it. A locking device is provided which prevents the removal of the swivel housing when the opening roller is rotating. This results in the opening roller being at a standstill when the swivel housing is removed. The risk of injury caused by a still rotating opening roller is eliminated.

Abstract: A yarn withdrawal device for open-end spinning arrangements has a yarn withdrawal nozzle and a balloon-breaking insert which extends the axial channel of the yarn withdrawal nozzle. The yarn withdrawal nozzle has a curved contact surface for deflecting a yarn to be withdrawn and simultaneously rotating the yarn in a crank-like manner, which contact surface graduates from a front surface into the axial channel. The balloon-breaking insert has an inner wall which is provided with raised areas and/or recesses, with which the yarn comes into contact. The contact surface of the yarn withdrawal nozzle is a smooth steel surface. The raised areas and/or the recesses of the balloon breaking insert are such that a yarn hairiness in the range of 3 mm in length is achievable. In addition, values in relation to the spinning stability, tear resistance and evenness can be achieved which are usual in the case of a notched contact surface of standard yarn withdrawal nozzles without a balloon-breaking insert.

Abstract: A double-apron drafting unit for spinning machines has a delivery roller pair and an apron pair arranged upstream therefrom. The apron pair guides a fiber strand in the area of a delivery nipping line, with which it forms a wedge-shaped gap. Devices are provided for keeping air currents, which circulate with the delivery roller pair, away from the area of the delivery nipping line, which devices are located outside of the wedge-shaped gap point formed by the delivery nipping line and the apron pair. The devices are, however, located in direct proximity to the delivery roller pair and the apron pair.

Abstract: In an arrangement for application in open-end rotor spinning, an opening roller is housed in a swivel housing. The swivel housing can, together with the assembled opening roller, be removed from the arrangement for open-end rotor spinning when the machine is in operation. The opening roller, due to its mass, continues to rotate after it has been separated from the tangential belt which drives it. A locking device is provided which prevents the removal of the swivel housing when the opening roller is rotating. This results in the opening roller being at a standstill when the swivel housing is removed. The risk of injury caused by a still rotating opening roller is eliminated.

Abstract: An arrangement for sealing an opening of a rotor housing in which a vacuum prevails, through which opening a shaft of a spinning rotor, supported outside of the rotor housing, projects. The arrangement has free floating sealing element arranged towards the opening and forming at least two sealing gaps with the spinning rotor. A first sealing gap is located between the sealing element and the shaft, a second sealing gap is located between the sealing element and a collar of the spinning rotor which borders the shaft. The sealing element can form an additional third sealing element with the back wall of the spinning rotor.

Abstract: The invention concerns a cleaning apparatus for the cleaning of a spin rotor of a spinning station with a cleaning head which can be insertably presented to the spin rotor and on which cleaning head are placed at least two scraper elements. In accord with the invention, the at least two scraper elements are pneumatically extendable, wherein the position of the at least two scraper elements are so secured on the outer circumference of the cleaning head, that the sum of the contact forces which are exerted from the scraper element in a radial direction onto the rotor is zero, or practically zero.

Abstract: The spinning stations of a spinning machine each have a drafting unit and a stopping device for fiber material fed to the drafting unit. A first carriage is movable along the length of the spinning machine, which carriage comprises a sensor for detecting a broken thread at a spinning station. Spatially separated from this first carriage is a second carriage, which is moveable along the length of the spinning machine, which second carriage is provided with an actuator for activating the stopping device of a spinning station in need of maintenance.

Abstract: In a process for condensing a drafted fiber strand in a condensing zone arranged downstream of a front roller pair of a drafting apparatus, the fiber strand is transported through the condensing zone by means of a perforated, suctioned transport belt. It is hereby provided that the fiber strand has the same direction of motion as the transport belt. Furthermore, it is ensured that a sufficient amount of the fibers located in the fiber strand are still nipped by the front roller pair during condensing. This results in the advantage that the front ends of the fibers of the fiber strand to be condensed do not insert themselves into the perforation of the transport belt, thus leading to clogging.

Abstract: A condensing zone for condensing a drafted fiber strand is disposed downstream of a front roller pair of a drafting unit of a ring spinning machine. The condensing zone comprises a stationary sliding surface having a suction slit, over which the fiber strand is transported by an air-permeable transport belt. The condensing zone is bordered on its exit side by a nipping roller disposed on the transport belt. The nipping roller drives the transport belt and is in turn driven by the front pressure roller of the drafting unit. The front pressure roller is, for this purpose, connected with the nipping roller via a drive belt, preferably a toothed belt. The nipping roller and the front pressure roller are arranged on supporting arms which can be spread apart and which tension the drive belt.

Abstract: In order to monitor the efficiency of a ring spinning machine, the doffed bobbins are analyzed with respect to their weight and/or appearance during their transport away from the machine. The bobbins are preferably transported away on peg trays, which are guided past a weighing device connected to the machine.