Some other machines are a lot simpler. Here's how the Philips (mady by Yamaha) CSM84 works. Smaller tape (8 and 12 mm) feeders are all mechanical. A plunger on the head pushes a lever on the feeder at the same time the head comes down. First, the feeder retracts a thin sliding plate that covers the top of the tape where the cover tape has already been peeled back. This exposes the pocket in the tape where the component is, allowing the nozzle to grab it. When the head is going back up, the plunger releases the feeder's lever, and a spring advances a ratchet pawl to turn the tape sprocket one notch of 4 mm. If the component requires a greater spacing, the plunger is commanded by the software to thump the lever up to 5 times to advance the tape the right amount. (This can get out of sync, and need manual pushes to get back in the right alignment with the tape pockets.) Larger tapes have pneumatic feeders, and the lever on the feeder opens an air valve to drive an air cylinder. This allows a much stronger spring, and the cylinders have stops with notches you set for 4,8,12,16, etc. mm of advance, to match the tape. With these, the software never needs to push the advance lever more than once.
The sliding cover I mentioned above lays right above the tape and prevents parts from bouncing out of the pockets, even when the feeder is turned upside down.
So, this is the most basic kind of feeder system, low cost, no motor, microprocessors, sensors, etc. in them, and it makes the head do most of the work.
Jon
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