THREAD-GUIDE SETTING DEVICE FOR STRAIGHT-BAR KNITTING MACHINES

摘要

A primary switch of a control circuit is closed to energize a motor and clutch to drive a carriage for relocating positive stops limiting travel of one or more thread guides and to energize a signalling device. The carriage and thread-guide stops are precisely positioned automatically by interposition of a preset blocking member between the source of a light beam, magnetic field or air jet of the signalling device and its signal receiver to open a secondary switch in the control circuit and thereby affect instantaneous deenergization of the motor and clutch and actuation of an auxiliary lock to prevent overtravel of the carriage on its feed screw. Alternatively, the clutch may be disengaged by a photoelectric counter responsive to the angle of rotation of the feed screw. Several signalling devices and receivers may be mounted on the carriage and connected in parallel to open sequentially secondary switches in the control circuit, in which case the primary switch is a sequential or stepping selector switch.