Abstract: According to a method and apparatus for controlling the insertion process of a weft yarn, the weft yarn is temporarily exposed to a braking friction and the yarn tension is mechanically picked-up. In order to prevent the friction from having a disturbing or damaging effect on the yarn, the yarn tension is only temporarily picked-up during certain phases of the insertion process, in order to derive information from the tension curve that is useful for the control of the insertion process. In a power loom, in particular a jet, rapier or gripper shuttle loom, a tension sensor for sensing the tension of the weft yarn can be switched during insertion between its sensing position and a passive position in which it does not touch the weft yarn. Preferably, the tension sensor is integrated in the insertion brake or even forms the braking element itself.

Abstract: A jet loom with a weft yarn insertion brake contains a braking element that is movable from a position of rest, on one side of the weft yarn, across the path of the weft yarn to a braking position. An electric motor, which drives the braking element, can be actuated during each insertion process of the loom. The electric motor preferably constitutes a fast response step or d.c. motor, whose direction of displacement can be switched and whose stroke can be individually adjusted for each set position of the braking element during the insertion process. Operation of the electric motor is controlled by an electronic control device. Programming within the control device can be modified between varying insertion processes so as to adapt the timing, stroke and driving direction of the electric motor. The driving force of the electric motor is transferred to the braking element by a constrained, inelastic link connecting the two.

Abstract: In a thread brake, which comprises at least one brake element (B) adapted to be moved relative to a counter brake element (B.sub.G), said brake elements acting on the thread in braking positions and being adapted to be displaced up to and into a threading position in which the thread can be moved undecelerated through the thread brake, and in the case of which a brake element adjustment device is provided, the threading position of the thread brake (F.sub.K, F.sub.L, F'.sub.L) can be established with the aid of a drive means (A) of said adjustment device, said thread brake having provided therein air guide surfaces (L), which, in the threading position, define an air guide passage used for automatic, pneumatic threading of the thread (Y) by means of a stream of air.

Abstract: An easily movable output brake system forms part of or cooperates with a yarn feeder (13) comprising a spatially fixed body supporting a yarn store, from which body a yarn (11) can be drawn off even at advanced speed through an output channel (10). The system comprises a first member (9) which is arranged in a bearing and which, in the functional operation of the system, by means of a surface clamps the yarn being drawn off against a counterstay member (15). The members (9, 15) are designed to effect a yarn-cleaning function dependent on the yarn rotation upon drawing-off, with simultaneous prevention of considerable accumulation of lint, particles etc., in respect of the members. The mobility of the system is obtained by the selection of the components in question.

Abstract: In the case of a thread braking device (B), which is intended to be used especially on the supply side of a thread feeder (F) and which comprises a thread brake (3) having a fixed passage axis (f) and having arranged thereon a shield surface (A) provided with a thread opening (22) and arranged transversely to the direction (R) in which the thread (Y) is supplied, there are provided direction adjustment means (M) for the shield surface (A), with the aid of which the transverse position of said shield surface (A) can be adjusted to supply directions (R1, R2) of the thread (Y) deviating from the passage axis (f). Even in the case of a shield surface (A) for general thread-guiding tasks, which is arranged in a stationary holding means and oriented transversely to the supply direction (R) of the thread (Y), such position adjustment means are provided so that the transverse position of the shield surface (A) can be adjusted to the respective supply direction (R1, R2) of the thread (Y).

Abstract: A monitoring system for knitting machines, in particular for such machines for the knitting of hosiery or socks, having a number of yearn guards allocated to each yarn for infeed into the machine, the guards each being operative, in response to a movement or absence of movement of the yarn, respectively, detected thereby, to generate and output signal to stop the machine in the event of yarn or thread breakage or other fault int h e yarn infeed, by the intermediary of preferably electronic control unit connected to the yarn guards. The control unit includes memory and comparison systems and is arranged to gather and memorize, during an introductory, correct and approved working or report cycle of the machine, information representing the yarn infeed phase in the form of the actual pattern of output signals from the yarn guards.

Abstract: In a method for positively feeding an elastic yarn to the knitting system of a circular knitting machine having a yarn feeder apparatus controlled by an electronic control unit, the apparatus of a take-out signal (A) initiates the count of a preselected number of position signals (p) before generating a stop signal (S), or otherwise the take-out signal (A) is disregarded for a preselected space of time at the end of which the stop signal (S) is generated, the number of position signals (p) or the space of time, respectively, being selected in accordance with the yarn quality and/or the distance between the yarn feeder apparatus and the knitting system. In this manner the yarn feeding operation is continued for relaxing the elastic yarn. The electronic control unit (3) of the yarn feeder apparatus (2) in the circular knitting machine (1) includes a delay circuit (19) for controlling the generation of the stop signal (S).

Abstract: A monitoring circuit for a knitting machine with at least one yarn feeding arrangement comprises two yarn monitoring devices which are provided with switches and connected via a first rectifier circuit and an indicating lamp to a supply line. The supply line is coupled to a supply voltage source in such a way that when one of the two yarn monitoring devices is operated, the indicating lamp is only activated by one half-wave which is associated with the yarn monitoring devices and belongs to an a.c. voltage signal generated by the supply voltage source. To improve the recognizability of an indication by the indicating lamp, the a.c. voltage signal generated by the supply voltage source has a first interval during which the signal has exclusively positive half-waves and a second interval during which the signal has exclusively negative a.c. voltage half-waves.

Abstract: A device for positive feeding of yarn to a knitting machine, which device has independently rotatable first and second wheels disposed axially closely adjacent and individually supported for rotation about first and second axes which extend in the same general direction but are slightly inclined relative to one another. First and second feeding tapes are drivingly engaged with the first and second wheels respectively. A shiftable yarn guiding element feeds a yarn therethrough to a selected one of the wheels, with the guiding element being shiftable between first and second positions to enable the yarn to be positively fed by the first and second wheels respectively.

Abstract: A yarn feeding device comprises a stationary storage drum from which the yarn can be withdrawn. The yarn feeding device can be operated at a positive feeding mode and at a non-positive feeding mode by means of a rotatable yarn guiding member arranged at the withdrawal end. The yarn guiding member comprises at least one yarn engagement element adapted for engaging the yarn when the rotational speed of the yarn spiralling around the withdrawal end of the storage drum tends to exceed the rotational speed of the yarn guiding member. The yarn engagement element comes out of engagement with the yarn when the rotational speed of the guiding member exceeds the rotational speed of the yarn spiralling around the withdrawal end of the storage drum.

Abstract: A yarn feeding device comprises a rotatable drum, a yarn-braking unit through which the yarn is guided at a certain wrapping angle, and a moveable detector element lying against the yarn for surveying the tension thereof and for detecting a possible yarn breakage. For enhancing the dynamic behavior of the detecting element and for reducing erroneous fault indication as generated by the detector element, the detector element is tensioned against the yarn such that the wrapping angle of the yarn passing the yarn-braking unit is increased when the yarn tension decreases.

Abstract: The take up means (5) is inhibited in response to a predetermined operating conditions of the flat knitting machine.

Abstract: A yarn feeding device adapted for positively feeding elastic yarn comprises an electric motor, a speed sensor for the speed of the knitting machine and a control unit connected to the electric motor and to the speed sensor. An optimal dynamic behavior of the yarn feeding device is obtained by making use of a rotatable drive cylinder connected to the electric motor, of a rotatable guide shaft supporting the yarn supply spool, which shaft is slidably arranged such that the yarn supply spool is kept in permanent contact with the drive cylinder, wherein the control unit drives said rotatable drive cylinder with a variable speed depending on the actual speed of the knitting machine and on a yarn demand signal, wherein the range of yarn feeding speeds is limited by predetermined minimum and maximum values.

Abstract: A yarn-feeding apparatus for selective positive feeding of several yarns to a knitting machine, comprising a sensor for generating sensor signals, the sensor signals representing the respective feeding condition or non-feeding condition of the yarns, and an error detection unit connected to the sensor for turning off the knitting machine in response to predetermined sensor signal combinations representing a yarn breakage and/or a yarn over-feed and/or a yarn change fault. For shortening the response time of the error detection unit and for enhancing the reliability thereof, the error detection unit comprises a working position sensing unit for generating position data representing the working position of the knitting machine, a logic circuit for deriving a yarn changing signal from the sensor signals, and a memory unit for storing yarn changing position data.

Abstract: A device for the positive feeding of a yarn, particularly for knitting machines, having a rotatable storage drum adapted to have a yarn supply wound thereonto and withdrawn therefrom over a rim thereof, a stationary yarn guide element located below the rim and outwards of the periphery of the rim in a center plane extending through the axis of rotation of the storage drum, a yarn guiding element located in the yarn path between the rim and the yarn guide element and formed with a yarn guiding edge, and a stoppage sensing element having a portion extending parallel to a tangent of the rim transversely of the yarn path between the yarn guiding edge and the yarn guide element, and being mounted for pivotal movement under the action of a biasing force.

Abstract: A yarn-feeding apparatus for the positive feeding of several yarns to a circular mechanism of a circular knitting machine, comprising fingers which are arranged in the circular mechanism for receiving and guiding the yarn into a knitting position or taking the yarn out of a knitting position, including delivery apparatus with each including a yarn-transporting element and a yarn-guiding element which is movable back and forth between a feeding area in which the yarn is in engagement with the yarn-transporting element and a nonfeeding area, and wherein for each yarn-guiding element there is provided an electric position sensor which produces an electric signal in dependence on the position of the yarn-guiding element.

Abstract: The invention relates to a yarn supply device group for attaching to a textile machine, in particular a ring knitting machine with electrically controllable switching and actuating devices in every supply device which are connected in a signal-transmitting circuit by a bunch of lines common to all supply devices to a central control mechanism. Previously, every supply device in the group had to be "marked" manually prior to the start of operation. In addition, a bunch of lines with large dimensions was necessary, since each supply device needed at least one separate line.

Abstract: The invention relates to a method for feeding yarns of different colors to a conventional knitting machine for producing striped fabrics (circle-striped fabrics). The first step of the method according to the invention consists in selecting and presenting a predetermined length of a yarn of a desired color in accordance with the striped pattern to be produced. The so selected and presented yarn lengths are subsequently joined to form a continuous yarn. In a third step, the continuous yarn formed of said joined yarn lengths is intermittently formed into an intermediate store, from which the yarn is positively fed to the knitting machine at a constant speed in synchronism with the operating speed of the knitting machine. In this fourth step of the method, the continuous yarn is fed to the associated knitting system of the machine.

Abstract: This invention relates to an apparatus for selective positive feeding of a plurality of yarns (Fa-Fd) to striping knitting machines, comprising a plurality of yarn feeding units (1), each having a number of yarn feeding devices. The invention proposes to use a single electromagnet (9) in each yarn feeding unit to move the yarn control elements (7'a-7'd) of all yarn feeding devices from their feeding to their non-feeding positions by means of a uni-directional coupling between the electromagnet (9) and the control elements (7'a-7'd) and to move the control elements in the reverse direction by means of an increase in yarn tension when the yarn (Fa-Fd) is being knitted into the fabric.