A knockout mechanism for a high-speed automatic cold heading machine having first and second eccentric shafts. A driving link is mounted on the first eccentric shaft by an antifriction bearing. A rocker arm is pivotally connected to the driving link at a location spaced from the connection of the link to the first shaft. The rocker arm is connected to the second shaft so that the rocker arm continuously oscillates. Knockout means including an ejecting rod are actuated by the rocker arm to eject a blank from a die of the machine. The stroke of the rocker arm is adjusted by adjusting the second eccentric shaft.
A driving apparatus includes a driving shaft journalled in a nut former, a hollow cylinder having an axially extending bore formed eccentrically therethrough and sleeved rigidly on the driving shaft in such a manner that the driving shaft extends through the bore of the cylinder, a link sleeved removably and rotatably on the cylinder at an end thereof, and a crank having a first crank arm connected pivotally to the other end of the link and a second crank arm connected to a workpiece impelling mechanism. When the driving shaft rotates, the driving apparatus activates the workpiece impelling mechanism.
