摘要:
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. The electric motor is controlled so that the driving force exerted on the braking element is always greater in magnitude than the greatest possible reaction force of the deflected weft yarn.
摘要:
In the case of a method of holding in position a rotatably supported thread storage surface in a thread storage and feed device, in which a group of components defining the storage surface is rotatably supported on a shaft adapted to be rotated in a housing and in which a winding-on member circulates together with the shaft, whereas magnets prevent the group of components from rotating together with the shaft, a rotational vibration damping connection is temporarily established between the housing and the group of components while the shaft is rotating In a thread storage and feed device (F), which is provided with an advance member (6) adapted to be driven such that it carries out a wobbling movement, there are arranged an externally supported rotational vibration damping member (X) and an abutment (Y) which is provided on the advance member (6). When the device (F) is equipped with a stop device including a movable stop element (23), the stop element (23) constitutes the rotational vibration damping member (X, 50).
摘要:
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.
摘要:
Method of controlling a plurality of relay nozzles (RNx) is a jet weaving machine. These nozzles are consecutively actuated for supporting the insertion of the weft yarn (WY) into the shed of the weaving machine and up to the arrival end (AE) of said shed by means of consecutively opening solenoid valve associated with nozzles. The valves are controlled on the basis of calculated information representing the momentary real position of the weft yarn (WY) during it path in the shed. The invention also relates to an apparatus for carrying out said method.
摘要:
A pulley with a variable working diameter, including two coaxial disks which are rotatable relative to one another, of which the one has a radial and the other at least one spiral-shaped guide groove. A plurality of support members with a segmentlike form are positioned between the disks and can be clamped with their front sides between the disks in different radial positions so that their radially outer peripheral areas define a polygonal path which is similar to a circle. The support members having projections engaged in the guide grooves of both disks so that relative rotation of the disks moves the support members radially for changing the respective circle diameter. Each support member--viewed in the direction of the axis of rotation of the disks--has the shape of an asymmetrical segment, preferably a circular-ring segment, with a longer and a shorter diagonal. An extension of the longer diagonal is spaced from but passes by on the same side of the axis of rotation of the disks as a perpendicular to a tangent on the spiral-shaped guide groove in the area of the support member.
摘要:
A rotatable shaft carries a winding instrumentality whereby thread to be temporarily stored is coiled around a thread drum rotatably mounted on the shaft. Rotation of the thread drum in the direction of shaft rotation is prevented by concentric relatively fixed and movable brake elements, the fixed one secured to housing for the apparatus, the movable one coaxially secured to the thread drum. One of the brake elements has a circumferential surface from which elongated resilient fingers project, the fingers being more or less radial to said surface and having their tips normally engaged under flexing bias against a circumferential braking surface on the other brake element. The thread passes through the zone of the fingers, and the several fingers are so inclined to radials from the common center of the brake elements that the thread, or a guide tube through which it extends, can flexingly cam each finger, in turn, out of engagement with the braking surface and pass around the finger.
摘要:
A device for feeding weft yarns to a weaving machine which includes a rotatingly driven retainer that is constructed such that it has little mass. The retainer is coupled to a rotary drive unit such that the retainer cannot move radially with respect to a storage drum axis so that, when viewed in the direction of circulation of the withdrawal point, the retainer continuously extends through a circulatory path ahead of the weft yarn. The rotary drive unit is additionally connected to a control device which controls the acceleration and deceleration of the retainer in accord with a speed profile and determines the process of weft insertion in the weaving machine.
摘要:
In a method for controlling a yarn storage and feeding device, particularly for a mechanical loom, comprising a storage surface adapted to have windings of a yarn wound thereonto and withdrawn therefrom by a consumer, and a control unit for a winding drive mechanism operable to adjust the winding speed in accordance with the consumption rate and in response at least to the actual value of the number of yarn windings on the storage surface, for adjusting the actual value towards a predetermined desired value, the desired value is altered in response to at least one alteration of the winding speed to thereby obtain an optimum smallness of the yarn supply on the storage surface. In a yarn storage and feeding device for performing this method, the control unit cooperates with a reference value memory (18) for the supply of desired values (nV) varying in a predetermined manner.
摘要:
An apparatus for detecting a yarn movement comprises a yarn guide unit for the sliding guidance of a moving yarn, and a converter cooperating with the yarn guide unit for generating an electric signal. With the aim of improving the signal-noise ratio of an apparatus of this type, there is provided a member mounted for movement relative to the yarn guide unit and disposed such that the yarn is guided between the member and the yarn guide unit in simultaneous contact with the member and the yarn guide unit, the member being subjected to a biasing action relative to the yarn guide unit.
摘要:
This device has a stationary storage durm (2) onto which an intermediate yarn store is wound by a winding-on device (3) and from which the yarn (WY) is withdrawn spiralling around the withdrawal end of the storage drum. The device also has a plurality of yarn stopping devices (10) being arranged at angular intervals around the storage drum, said yarn stopping devices consisting of yarn stopping elements (14) and of actuator means (11) moving said stopping elements into and out of the path of the yarn being withdrawn, and an actuator control device (8) adjustable to desired yarn lengths to be withdrawn, said control device transmitting actuating signals to said plurality of yarn stopping devices. The control device (8) comprises storing means (20) for storing an information regarding the yarn stopping device actuated at the end of the next preceding yarn withdrawal cycle, and calculating means (20) for determining a selected series sequence of said yarn stopping devices to be alternately actuated and de-actuated consecutively during the yarn withdrawal cycle on the basis of said stored information and of an adjustable input information for the calculating means representing at least one significant parameter for the distance/time function of the weft yarn insertion process cycle. The calculating means (20) also determines the yarn stopping device to be kept actuated at the end of the present weft yarn withdrawal cycle at last one in said selected series sequence of alternately actuated and de-actuated yarn stopping devices, on the basis of said stored information and of an input information representing said desired yarn length.