Variable pitch tape feeder and pitch selection switch therefor

Abstract

In a variable-pitch tape feeder for feeding parts to a pick and place machine used to produce electronic circuit boards, a switch assembly is provided which controls the limits of a shutter movement and the tape advance distance dependent upon the desired pitch. The tape feeder uses a carrier tape to deliver parts to the pick and place machine. The parts are inserted into depressions at regular intervals along the length of the tape. To accommodate tapes of varying pitches, i.e., distances between parts, the feeder uses an electronic control unit to drive the tape feed mechanism and actuate a shutter. The shutter prevents small parts from escaping their respective depressions prematurely. The switch provides a stop surface which limits the rearward travel of the shutter and a flag which is detected by optical sensors to determine the position of the switch and thus the pitch desired by the operator. By limiting the rearward travel of the shutter, especially when using small-pitch parts, parts subsequent to the one positioned at the pick-up point will be prevented from escaping their respective recesses in the carrier tape. A control unit electronically advances the carrier tape the desired distance according to the position of the switch.