Counter for small objects - uses photodetectors to count resistors, diodes, etc. with facility to stop motion of belt in event of irregularity

摘要

Two photodetectors (6,7) driving a set-reset flip-flop actuate a digital counter for the counting of small objects, such as resistors or diodes held in belts (4,5), which are moving at high speed past the photodetectors. The photodetectors are separated by a distance less than the minimum separation of the components to be counted, but greater than the maximum width of the components. A pulse is supplied to the counter whenever the obscuration of the first photodetector is followed by obscuration of the second photodetector. If both photodetectors are simultaneously obscured indicating misalignment of the components, or a fault on the photodetectors, the two outputs of the set-reset flip-flop are connected to a NAND gate which emits a signal to stop the motion of the objects being counted.