Abstract: An apparatus for the arrival monitoring of a weft in a jet loom with a reed pivotal between a first position and a second position. The reed has a longitudinal channel for the weft. An arm is mounted on the reed with the free end of the arm in the proximity of the longitudinal channel. The free end supports a light source and two light-sensitive elements. The light source is directed towards a central part of the channel for illuminating the rear portion of the channel. One light-sensitive element is directed towards the upper corner of the channel, while the other light-sensitive element is directed towards the lower corner of the channel.

Abstract: Apparatus for monitoring one or more electric signals representing movement of objects such as threads, strips, or the like during one or more surveillance time periods. A first signal detector detects the electrical signals representative of the movement. A trigger-signal-generating circuit generates a trigger signal upon detection of an electrical signal of at least a predetermined magnitude. A second signal detector is responsive to trigger signals to activate a surveillance circuit which indicates detection of a moving object. The apparatus includes a device for increasing the sensitivity of one or both of the signal detectors during all or part of the surveillance period.

Abstract: A plurality of signal generators are provided, one signal generator being associated with each object for example threads, strips, or the like whose motion is to be detected. Each signal generator generates an electric signal upon detection of movement of its associated object. The signal generators are connected in a series circuit, each end of which is connected to the input of a separate signal amplifier. The connections between adjacent signal generators in the series circuit are successively grounded. The signal amplifiers have their outputs connected to a gate circuit, the output of which is connected to the device for successively grounding the signal circuit connections so that, if a signal is generated simultaneously by at least one signal generator on each side of the grounded connection, operation is interrupted.