Abstract: A detector device is provided, in particular for detecting faulty needles or closed needle latches in a knitting machine with latch type needles, consisting of a non-electrically-conductive feeler which is normally resiliently urged into contact with the upper parts of the needle hooks, and an electrically-conductive probe which normally does not contact the needles but passes through the needle hook openings as relative movement of the needles past the detector takes place. However, if a needle latch is closed the probe makes contact with it and also if the needle hook is broken or bent the feeler is permitted to move laterally thereby enabling the probe to contact the faulty needle, contact of the probe with a needle completing an electrical circuit which signals a needle fault. For circular knitting machines in which the needles travel past the detector, the detector is associated with a controller that stops the machine when the faulty needle reaches a particular position in the needle travel path.

Abstract: A method and apparatus for detecting defective knitting needles in a circular knitting machine wherein the knitting needles are advanced along a circular path between a light source and upper and lower vertically spaced photoelectric detector devices. The direction of the light beams from the source to the two photoelectric devices is inclined at an angle to the tangent of the circular path at the beam intercept with the circular path, such that the advancing needles pass successively through the beams and a shadow of the hook end of each needle is cast on the upper photoelectric device before any shadow of any other part of the needle is cast on the lower photoelectric device, when a nondefective intact needle enters the beams. Needles with broken off hooks or closed needle latches cause a shadow to be cast on the lower photoelectric device before any shadow reaches the upper photoelectric device to activate an alarm and/or stop the knitting machine.