Lindauer Dornier Gesellschaft Mbh

Werner Birner

Adnan Wahhoud

Peter Czura

Josef Hehle

Hans-Dieter Scorl

Herbert Reinhardt

Christian Hannes

Peter D Dornier

Peter Schiller

Alexander Chvorak

Walther Truyen

The leading end of a weft thread exiting from a weft insertion channel in an air jet weaving loom is monitored by a weft stop motion positioned in a weft stretching channel directly downstream, as viewed in the weft motion direction, of an exit of the weft insertion channel. The weft stop motion is either an additional weft stop motion monitor or it is the first weft stop motion device repositioned from a location at the exit of the weft insertion channel to a location in the weft stretching channel. In such a position in the weft stretching channel faults or deformations such as a loop in the leading end section of the weft thread are readily or positively detected for generating a respective loom control signal.

Method and apparatus for monitoring a leading end of a weft thread in a stretching channel in an air jet loom

A supply spool supplies a weft thread through an adjustable actuated thread brake and a thread tension sensor to a weft thread accumulator, from which an accumulated insertion length of the thread is provided to a weft insertion device. The tension sensor provides a measured actual thread tension signal to a control arrangement, which compares the actual tension to a selected rated tension, and, dependent on the deviation therebetween, provides a control signal to an actuator of the thread brake, so that the actual thread tension constantly corresponds to the selected rated tension. Another sensor provides a signal indicating a change from an empty spool to a full spool. Responsive thereto, the control arrangement actuates the thread brake to an adjustable starting brake setting as a coarse adjustment. Then the self-regulating fine adjustment is continued. A constant winding tension and thread accumulation length are achieved in the thread accumulator.

Method and apparatus for variably braking the weft thread between a supply spool and a thread store in a loom

A method and a device limit the normal shed opening angle (&agr;) of warp threads in an open loom shed, to a smaller limited shed opening angle (&agr;,) that applies to the selvedge warp threads over a selvedge laying-in width at the edge of the fabric. The limited shed opening angle (&agr;,) is smaller than the normal shed opening angle (&agr;) and is selected to provide optimal positioning and binding-in of the free thread end of a beat-up weft thread that is guided back and laid or tucked into the next open shed to form a high quality laid-in selvedge. The shed opening limit device includes two thread-constraining prongs that extend perpendicularly to the direction of the warp threads at least along the desired laid-in depth of the selvedge. The selvedge warp threads are guided and constrained between the prongs so that the extent of shed opening of the selvedge warp threads is limited to the limited angle (&agr;,).

Method and arrangement for limiting the loom shed opening angle

A wide selvage is formed along a fabric edge in a weaving loom by at least two selvage forming heads arranged in a row with an outer selvage forming head (9) and an inner selvage forming head (8) positioned between the outer selvage forming head (9) and an edge of a fabric. The outer selvage forming head (9) seizes a weft end and transmits it to the inner selvage forming head (8) which inserts it into the shed for beat-up. Both forming heads work pneumatically and in tandem with each other. A set of two selvage forming heads (8, 9) is arranged at each fabric edge.

Method and selvage forming device for an air weaving loom

The weaving of terry cloth is improved by preventing slackening of the warp threads during beat-up. The warp threads are kept in contact with a warp tensioning faller roller (8) at all times. For this purpose the faller roller (8) is eccentrically mounted and biased by a spring (46) retraction force applied through a control lever (48). The force of the spring (46) is in balance with the tension on the warp threads (4), whereby the spring (46) causes a warp length compensation during shed formation. A piston rod (52A) of a piston cylinder drive (52) acts on the control lever (48) of the faller roller (8). By pressurizing the cylinder (52), the faller roller (8) is tilted about an eccentrically mounted bearing shaft (14) and a rated pile warp thread length (54) is delivered or fed, without the pile warp threads (4) lifting away from the faller roller (8). One chamber of the drive cylinder (52) is periodically pressurized in synchronism with the terry cloth drive (17) for the beat-up of a group of weft yarn threads or both chambers of the drive cylinder (52) are pressurized for weaving a border or trim.

Pile warp thread tension control apparatus for terry cloth weaving

In an air jet loom, a method is provided for avoiding weaving a faulty weft thread such as a broken weft thread into the cloth being woven. When a faulty weft thread is inserted into the loom shed, the failure of the thread to traverse the weaving width is detected preferably optoelectronically by a suitable sensor. Thereupon the weaving operation of the loom is interrupted and a repair thread is inserted into the loom shed to remove the faulty weft thread. The length of the repair thread is less than the normal length of the weft threads that are inserted for the usual weaving operation. Thereby the repair thread is too short by itself to reach the weft thread sensor, and only when the faulty thread is properly connected to the repair thread will the sensor be triggered.

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Lindau, Germany

Werner Birner