Abstract: A system for moving yarn under substantially constant tension, including a translationally-fixed pivoting device, having a neutral position, for applying tension to the yarn, and a variable-speed yarn drive for moving the yarn across the pivoting device. The rotational position of the pivoting device is determined in relation to its neutral position, and in response, the speed of the yarn drive is altered to move the pivoting device closer to its neutral position for maintaining a relatively constant tension on the yarn.

Abstract: A fabric pickup device which separates single layers from a stack of fabric layers comprises a mounting plate (1) by which it may be secured to a table (2), an angled bracket (6) extending the full width of the device, and a pickup assembly (8). The pickup assembly (8) is supplied with compressed air to operate three double-acting pneumatic cylinders (20, 21, 22). Two pickup plates (29, 30) have on their lower surfaces needles (39, 40 respectively). Operation of the cylinders (20, 21) causes the plates to be pivoted between a standby position, a pickup position in which a fabric layer is picked up on the needles, and a release position by means of a cam plate (53). Operation of cylinder (22) causes the pickup assembly to be raised so that the fabric layer picked up may be separated from the needles (39, 40).

Abstract: A mechanism for effecting guide bar lapping movement in warp knitting machines comprises a double-acting piston-in-cylinder servo arrangement connected directly to the guide bar. The piston 13 of the arrangement 11 may be connected by a rigid yoke arrangement 15 to a rod 16 slidable in linear bearings 17 and connected to the guide bar 12.

Abstract: A method for operating the guide bars of warp knitting machines comprises feeding in to a computer desired lapping instructions, the computer being programmed to discriminate between permitted and prohibited lapping movements and being operative to prevent the attempted execution of prohibited movements. The computer can be programmed to test instructions against a set of mandatory rules, which proscribe lapping movements that would crash the guide bars, and may also be programmed to discriminate against ineffective lapping movements.