Lindauer Dornier Gmbh

Lindauer Dornier Gesellschaft Mbh

Ewald Zimmermann

Herbert Mueller

Adnan Wahhoud

Peter Czura

Dieter Teufel

Martin Eberle

The starting time of a weft thread insertion in a jet loom is automatically adapted to a change in the speed of the main loom drive shaft, in order to assure that the leading end of the weft thread always arrives at the same time at a weft stop motion device at an exit end of a weft insertion channel through the loom shed. For this purpose, the starting time of the weft insertion is advanced when the loom drive shaft rpm is increased and delayed when the rpm is decreased. The advance or delay has reference to a weaving cycle that begins with the opening of a shed and ends when the shed is fully closed. The flight time .DELTA.t.sub.F of a weft thread through the shed is constant. The adaptation is performed in response to measuring the rotational drive shaft angle .alpha..sub.AR at which a weft thread arrives at the weft stop motion device and determining the starting time in such a way that the weft arrival time (t.sub.2, t.sub.4, t.sub.6) always takes place at substantially the same rotational drive shaft angle .alpha..sub.AR.

Method and apparatus for determining the starting time of the weft

In the event of an interruption of the weaving process and in the case of weaving-technical operations, such as tabby weaving and unraveling, a trailing of warp thread bobbins and thus a trailing of warp threads which are withdrawn from the bobbins and form a warp thread family, cannot be avoided without significant expenditures. The trailing results in a so-called trailing length in the thread family which, unless it is correspondingly taken up and correspondingly released during the new start of the weaving process, results in an overstretching of the warp thread family during a starting operation of the bobbins. This disadvantage is avoided by deflecting the thread family within a feeding stand, in the event of a weaving stop, in a controlled manner from a reference plane into at least one defined position. At the new start of the weaving process, the deflection is eliminated in a controlled manner.

Controlled warp tensioning during fabric weaving

A gripper loom is equipped along its reed or slay beam with a plurality of compartments formed by separation walls extending in parallel to each other and in parallel to the lower shed forming warp threads which pass through these compartments. The upper edges of the separation walls are aligned with each other and with a guide surface of the gripper rods so that the upper edges form extension guide surfaces for the gripper rods. Thus, the lower shed forming warp threads do not interfere with the proper motion of the gripper rods.

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Meerbusch, Germany

Ewald Zimmermann