| 摘要 |
<p>A mechanism for giving control over the unwinding of a wrap comprising a web of threads wound on a beam in a loom or warp knitting frame, having a take up roller for the fabric and >=1 beam, includes a differential, acting as a comparator between the length of the fabric produced and the length of warp let off by the beam motion, which generates variations in pressure in a pneumatic system, by the opening and closing of a valve. In the differential, the rotation of one of the planetary gears is controlled from the fabric take up roller, whilst the other planetary wheel is regulated by the linear unrolling of the wrap threads. The system can be adapted to most existing beam let off motions, converting them to positive operation, i.e., so that they let off a length of warp which is determined by the design of the fabric. There is always the possibility of negative control if the technical conditions call for it.</p> |
