Abstract: The invention aims at equalizing weft time differences when launching successive threads and thereby obtaining a more uniform cloth. For that purpose the thread velocity in the initial phase of the weft is measured and on the basis thereof an additional pressure impulse of the conveying fluid may be supplied to the thread. According to a different possibility, in dependence on the measured value, the thread is more or less braked by means of a brake at the end of the weft phase.
Abstract: This transport is effected by means of an injector, e.g. while inserting a weft thread into a weaving machine. In order to therewith keep the air consumption as low as possible the diameter of the discharge tube is made as small as possible. For nevertheless increasing the force imparted to the thread and thereby its directional stability the invention uses with an injector for subsonic inlet flow of the gas a discharge tube which widens along a very small conical angle, such that over its full length the gas obtains the speed of sound. With an injector for supersonic flow of the inlet gas this supersonic velocity is maintained along the full length of the discharge tube likewise by widening the discharge tube along a very small conical angle.The directional stability of the thread is further increased if, by keeping constant the cross-sectional area of the discharge tube, it is flattened in the direction perpendicular to the plane of the warp threads.
Abstract: An auxiliary member or accessory serves to reduce or limit the length of a weaving reed for the purpose of adapting it to the desired weaving width, so that the same reed can be used for differing weaving widths. The auxiliary member or accessory can be a stretching device or a detection device for the inserted weft threads. A flange of the auxiliary member is inserted between two reed lamallae or dents and is fixed on the rear side of the read by means of a locking element.
Abstract: The transport of a flexible thread is effected by means of an injector for inserting a weft thread into a weaving mechine. In order to therewith keep the air consumption as low as possible the diameter of the discharge tube is made as small as possible. For nevertheless increasing the force imparted to the thread and thereby its directional stability the invention uses with an injector for subsonic inlet flow of the gas a discharge tube which widens along a very small conical angle, such that over its full length the gas obtains the speed of sound. With an injector for supersonic flow of the inlet gas this supersonic velocity is maintained along the full length of the discharge tube likewise by widening the discharge tube along a very small conical angle.The directional stability of the thread is further increased if, by keeping constant the cross-sectional area of the discharge tube, it is flattened in the direction perpendicular to the plane of the warp threads.
Abstract: When cutting the successive weft lengths after they have been inserted into the weaving shed, the tail ends are retained in a clamping device. Thereby shifting the weft lengths in the winding direction of the cloth is difficult. According to the invention this disadvantage is removed in that the clamping device comprises a stationary clamping element and a movable clamping element cooperating therewith and movable in the direction of the beating up movement of the reed.
Abstract: Different weft threads are drawn off of different supply spools and are inserted through a first and a second jet arrangement in accordance with a predetermined insertion sequence. In the process, the fluid supply pressure for at least a portion of the second jet arrangement is selected at different values for the different types of weft thread. This pressure is changed synchronously with the weft insertion sequence. In this way, different weft thread types may be inserted in combinations not heretofore possible without leading to problems, e.g., operating problems or weaving faults. These problems are avoided since the weft threads of each type are transported optimally and gently, and are held taut without damaging the threads.
Abstract: This weaving machine comprises a device for removing faulty weft threads from the weaving shed or the woven cloth respectively, also if they have already been cut from the yarn supply during the weaving cycle. The device has a reciprocatable mechanical removing member (8) by means of which also fibrous yarn threads may be removed from the beating up line. Furthermore the device comprises a catching element (10) for threads which have already been cut, which element is adapted to clamp and take along the thread.
Abstract: The weaving machine has a device which is movable in the weft direction and comprises a loosening element adapted to be moved transverse to the weft direction and a catching element movable perpendicular to the cloth plane. Thereby also weft portions may be removed which have already been cut off from the yarn supply as well as broken weft portions.
Abstract: A pneumatic weaving machine has an air transport channel for blowing the weft threads, formed by the reed lamellae and open at one side. A plurality of auxiliary blowing nozzles are directed through this open side obliquely inward. The invention provides means whereby the jet direction of the auxiliary nozzles may be influenced such that a larger or smaller component transverse to the weft direction is obtained. Thereby friction forces on the thread may be controlled dependent on the yarn type.
Abstract: In a shuttleless weaving machine with a nozzle for inserting the weft thread. The nozzle is furnished with a mixing tube, and the machine has a weft thread guide channel and a reed carried by a batten, for beating-up a weft thread. A thread clamp or holder is disposed in the mixing tube of the nozzle. This thread clamp or holder clamps the weft thread ahead of the point where the weft thread is cut. Thus, the weft thread is prevented from springing back into the nozzle. Accordingly, damage to the weft thread due to such springing-back is prevented, the weft thread is protected and conserved, the fabric quality is improved, and the area of applicability of jet weaving machines is broadened. In addition it is ensured that the leading end of the weft thread is blown into the weft thread guide channel in a position which is as close as possible to the desired position with respect to the guide channel transverse to the insertion direction.
Abstract: A jet weaving machine is provided with an inserting nozzle at one end of the shed, a guide channel (7) comprised of lamellae (3) (e.g., the reed dents) arranged over the width of the warp shed, for guiding the weft thread during insertion in the shed, a first weft thread monitor (8) disposed in the region of the far end of the shed for emitting a signal when the inserted weft thread has not reached its intended length, and a tensioning device (9) located beyond the first weft thread monitor (8) in the direction of weft insertion (A), for stretching, straightening, and holding (taut) the inserted weft thread until beating-up is performed. The tensioning device (9) is in the form of an element through which an auxiliary fluid flows to take the head of the inserted weft thread which projects out of the shed and bend it transversely away from the weft insertion direction (A).
Abstract: The device has a winding drum with thread guide and a rotatable disc having pins for successively moving yarn coils from the drum. The pins are driven by cranks, the crank shafts of which are driven by a second disc provided in eccentric relation to the first disc. Thereby the rotational velocity of the thread guide may be increased relative to that of the pins so that each yarn coil may comprise more windings while maintaining the separation accuracy between successive coils.
Abstract: The impulse transmission of the transporting fluid to the weft yarn may be different, also with yarns of the same type, through different causes, particularly when a switching takes place from one yarn packet to a next yarn packet. According to the invention this switching is now detected in that the yarn section constituting the connection between both packets moves past a detector which emits a signal whereby the feed pressure for the blowing nozzle launching the weft threads into the weaving shed is temporarily varied.
Abstract: The speed of the movement of each weft thread through the shed is correlated with the speed of operation of the weaving machine by measuring the time occupied by movement of a weft thread through the shed, generating a first electrical signal which is a measure of such time, generating a second electrical signal which is a measure of a predetermined fraction of the time occupied by a weaving cycle of the machine, comparing said electrical signals and generating a third electrical signal which is a measure of the discrepancy between the first and second signals, and using the third signal to control one of such speeds in order to eliminate the discrepancy between the first and second signals.
Abstract: The mixing tube of the injector is narrowed at its exit end in at least one direction while retaining the cross-sectional area equal to that of the remainder of the tube. Thereby the directional stability of the thread is improved, while the friction surface presented by the tube to the thread is only slightly increased, exclusively at the tube extremity. The narrowing may be done by flattening the mixing tube end.
Abstract: A shuttleless weaving machine has a shedding mechanism, a weft conveyor for launching a weft thread through a weaving shed provided by the shedding mechanism, and a plural weft preparation device for delivering weft threads according to a repeating pattern to the weft conveyor. There is a disconnectable coupling between the plural weft preparation device and the shedding mechanism. An angular position comparator includes a part coupled to the shedding mechanism and a part coupled to the plural weft preparation device, said parts assuming a marked angular position relative to each other during normal operation while rotating through 1/(an) revolution per weaving cycle (a=number of wefts after which the weft pattern is repeated, and n=number of marked angular positions). Means are provided for detecting such marked relative angular position of the two parts, which means operate, while such position is not detected, to disconnect said coupling.
Abstract: A winding drum (8) for forming the storage coils has pins or ribs (11) extending substantially in axial direction of the drum.In a known winding drum the ends of the pins where the thread coil leaves the drum slightly converge towards the drum axis, thereby forming a conical drum part. According to the invention at least some pins (11b) are parallel to the drum axis which prevents the coil to leave the drum (8) too abruptly, so that the release pattern of the coils is more uniform.
Abstract: A method for inserting a measured weft thread length by means of a blowing nozzle, in which the transport air jet at the end of the weaving shed remote from said nozzle is deviated together with the thread length end through an angle relative to the insert direction and is entered into a mixing tube by means of an auxiliary air jet. The invention aims at having the auxiliary air jet acting substantially only for stretching the thread directly beside the cloth edge. This is achieved in that the auxiliary air jet is supplied as a concentrated jet centrally into the deviating transport air jet.
Abstract: A handtool (1,2) for threading e.g. a weft yarn in a pneumatic weaving machine has a conduit (8,9) issuing therefrom, the free end of which constituting a blowing nozzle (9). Adjacent to the nozzle aperture a guiding surface (3) for the yarn is provided. This tool may be used in difficultly accessible points of the yarn path through the machine. The yarn is presented to the guiding surface (3) of the tool whereafter it is carried along by the air jet of the blowing nozzle (9). In one embodiment the tool has a thread guiding eye (4) with a lateral release slot (5).
Abstract: A device for forming store units from a thread supplied from a yarn packet. The store units are formed on a winding drum between limiting pins which may assume an operative and an inoperative position. A brake means, e.g. brake shoe, is applied to the last part of a thread winding being released from the drum in order to avoid pulls and thereby tension peaks on the thread which otherwise might cause thread failure.