Lindauer Dornier Gesellschaft Mbh

Lindauer Dornier Gmbh

Fritz Gehring

Valentin Krumm

Stephan Arndt

Herbert Mueller

Florian Windischbauer

Siegbert Gsell

Walter Lindenmueller

Horst Haussler

Gerhard Hofmaier

Harald Storr

Siegfried Roth

Hans-Juergen Semrau

When a faulty weft thread must be removed after it has been bound into the fabric and beat-up, it is necessary to perform a so-called reverse weaving operation following the stopping of the normal weaving operation in response to a stop signal signifying that a faulty weft thread has been detected. For this purpose the loom main shaft and the heald drive shaft are rotated for a number of rotational degrees in the same direction in which these shafts are rotated just prior to the stopping of a weaving operation in response to the above mentioned signal. Next, the drive between the main shaft and the heald shaft is interrupted. Next, the main shaft and thus also the reed shaft and with it the reed, are rotated back within a predetermined angular range between two successive reed beat-up motions. During this time the heald shaft is rotated back, preferably to the so-called detection point with a higher r.p.m., or rather with a higher angular speed than the main shaft. This function is accomplished by an auxiliary step-up transmission gear between the main shaft and the heald shaft. The auxiliary gear is bypassed during normal operation when there is no weft fault and it is connected in series during the operation for removing of a faulty weft thread.

Loom method and apparatus for avoiding beat up markings in a fabric

A weft thread inserting gripper for a loom is equipped with a guide element attached to a side wall of the gripper. In order to enable the guide element to properly contact the reed when the gripper moves in the loom shed, the guide element and gripper combination is so constructed that at least the guide element can tilt about a journal axis extending in parallel to the direction of gripper movement. This tilting ability can be achieved by mounting the guide element itself to a gripper side wall for pivoting about the journal axis. The same tilting effect can be achieved by mounting the entire gripper side wall carrying the guide element on such a journal axis. Both possibilities assure an optimal surface contact between the guide element and the respective surface in the loom to provide a quiet and smooth gripper motion.

Weft thread inserting gripper having a guide element for a shuttleless

Weft threads are presented to a gripper in shuttleless looms by needles, each guided by at least one straight guide held askew in a needle guide carrier (9). These straight needle guides due to their askew arrangement make sure that all needles together are located in and displaceable in a fan type plane twisted in space. In the working position for presenting a weft thread each needle eye is located on a short line (7) extending approximately in parallel to a gripper path. Thus, all weft threads in their presenting position are close to each other in a narrow presenting zone within the reach of the gripper path for a sure gripping at the beginning of the forward gripper motion. At its beginning the gripper speed is still slow so that the weft threads are gripped gently. The straight needle guides held askew in the at least one guide carrier (9) form a row of guides which is slanted by a given angle relative to the gripper path to form the fan type plane twisted in space. A second row of askew straight guides may be arranged in a second guide carrier ( 10).

Apparatus for presenting weft threads to a gripper in shuttleless looms

The weft thread is inserted into a loom shed by a gripper seizing the thread end with clamping jaws. The thread end is presented to the jaws by a suction effect when the jaws are at a standstill or just starting to move toward the loom shed. The suction effect cooperates with a thread pull-back member and, if desired, with an auxiliary thread clamp for shortening the length of thread protruding from the jaws to reduce waste. The suction effect is applied by a suction pipe having a suction slot extending across the suction pipe in the direction of the weft thread between a cut-off point and a thread presenting eyelet. The suction slot merges into a suction channel leading the free thread end into the clamping jaws and for continuously holding the thread end between cut-off and renewed seizing of the thread end by the gripper clamping jaws for a gentle handling of the weft thread.

Method and apparatus for inserting weft threads into the loom shed of

A gripper rod for a shuttleless loom has a toothed rack section made of fiber reinforced synthetic composite, preferably thermoplastic, material. The toothed rack is made of a stack of belts of such material with rectangular perforations increasing in size from the inside out or from the bottom up. By compressing and simultaneously heating the stack the matrix material is cured, whereby the belts are bonded to one another. The gaps between the teeth may extend entirely through the rod or the rod may have a base also made of such belts but not having any perforations.

Gripper rod for shuttleless looms

A weft thread brake for shuttleless weaving machines includes two leaf springs or lamellae which rest against each other in a spring elastic manner. The thread, such as a weft thread, passes through a passage formed between the two leaf springs as the thread is being pulled off a supply reel or bobbin whereby the two leaf springs apply a braking action to the thread. In their basic position the leaf springs exert a first step of a defined braking action on the thread. Additionally, controllable members are arranged for cooperation with the leaf spring or springs to increase or decrease the pressure of the two leaf springs toward each other. Electromagnets, compression elements, or the like, are suitable for this purpose, whereby the actuation of these control members increase the braking action even to the extent of clamping the weft thread between the leaf springs if desired.

Weft thread braking mechanism having a stepwise controllable braking

In a shuttleless weaving machine wherein the filling yarn is inserted from both sides of the shed by means of gripper systems provided with filling yarn clamping devices and advanced into and then retracted from the shed. The filling yarn is transferred from one gripper system to the other by a controlled opening and closing of the clamping devices. For this purpose, a guide rod mounted in a straight guide on the reed stay and displaceable toward the shed is provided, which is equipped at its end with a control finger. The control finger passes through the warp yarns of the shed and actuates the clamping device in the shed. The control motion is transmitted through a cam follower roller mounted on a rocker lever hinged to a coupling link which in turn is pivoted or hinged to the guide rod. The control finger is entirely pulled downwardly out of the shed for the reed beat-up. The masses which must be accelerated together with the reed are low and control finger vibrations are eliminated.

Apparatus for the constrained actuation of the clamping system of

In a shuttleless weaving machine wherein the filling yarn is inserted into the shed from both sides by gripper systems provided with clamping devices and advanced into and then retracted from the shed, the filling yarn is transferred by a controlled opening and closing of the clamping devices from one gripper system to the other. An articulated link drive including a second rocker arm pivotally supported at a fixed point in the machine is provided for this purpose. The articulated link drive is driven by a cam and cam follower on a first rocker arm connected to the link drive by a coupling link. One link of the articulated link drive has an extension which controls the clamping devices in the shed. The dimensions of the articulated link drive are such that the coupling curve described by the control extension during the time of the reed beat-up leads to a non-interfering rest position underneath the path of the batten or sley. All parts of the control drive are located outside the batten or sley and are not tilted together with the sley during reed beat-up.

The invention relates to a shuttleless weaving machine with a reciprocating filling yarn inserting gripping member or rapier and a reciprocating pulling out gripping member or rapier forming a gripper device (1). In order to shorten the waste in filling yarn and to present a filling yarn (S1) selected by a yarn feed system in a specific position, the feed system forms a fanning-out arrangement in such a manner that each of the yarn guides (3), when in its operational position (3'), always assumes the same position. A holding device (8) for the cut-off end of the selected filling yarn (S1) is made to sufficiently yield the held yarn end, whereby the yarn end held by the holding device (8) can be retracted a distance by a controlled yarn retraction system (4, 12). The yarn retraction system (4, 12) is located between the path of the gripper device (1) and the yarn guides (3) of the feed system.

Shuttleless weaving machine with gripper systems for the filling yarn

This invention relates to an improvement in a device for coupling a heddle frame to reciprocatable drive bars with a first coupling part mounted on the frame of the heddle and with a second coupling part mounted to a drive bar, one of the coupling parts comprising drive means insertable between two parallel wall parts of the other coupling part, the coupling parts acting together by means of drive surfaces arranged transversely to the drive direction of the drive bar, the improvement which comprises the drive means being a hook-shaped element having wedging surfaces extending essentially transversely to the main direction of force of the drive bar and diverging toward the hook opening, a shaped element supported by a bearing in order to be limited in rotation positioned between the wall parts and provided with correspondingly located mating wedging surfaces adapted to be received in the hook-shaped element, means for pivoting the drive bar, together with the coupling part thereon, in the plane of the heddle frame to engage the other coupling part, and means for locking the coupling parts together in the plane.

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Lindau-Bodolz, Germany

Fritz Gehring