Weft projectile braking monitor - has sensor to detect impact on lever pushed by incoming projectile at the brake

摘要

The detector, to register faulty braking of the weft-carrying projectile in a shuttleless loom, has an impact sensor (5) at the lever (4) pushed back by the incoming projectile at the brake. The sensor (5) is at the trailing end of the lever (4) to detect impacts in the direction of lever movement when pressed back. The sensor (5) is a piezo-electric unit with a crystal bonded to one side to a projecting carrier. The detector (5) is connected to a signal evaluation circuit to act on them within a given time window, and discriminate from other projectile flight signals outside this time span, using a time measurement circuit to establish the impact detection signals accordings to the loom operating cycle and the relevant time window. ADVANTAGE - The appts. gives an automatic braking loss detection without affecting the loom working.