Cam 2 rotates about fixed axis A and has two lobes with profiled working surfaces a. Ram 1 reciprocates in fixed guides B-B and has punch d for making holes in the stock. Pin b on ram 1 comes into contact periodically with one of working surfaces a of cam 2. When the cam lobe turns out of engagement with pin b, ram 1 with weight D at its upper end drops and punches a hole in the stock. In one revolution of cam 2, ram 1 is raised twice and dropped twice.
$3171$SmC,FD$