High speed dynamics of a press feed mechanism. Part I. Theory

The theoretical part of a research effort, which dealt with the development and testing of a mathematical model of an industrial lever type roll feed mechanism, is given. This device, which is used in all manner of powerpress work, consists of an RSSR Linkage with a bent coupler, an indexing-type sprag clutch, a set of feed and pressure rollers, which move a metal strip into a die, and a disc brake. Its intermittent motion has been characterized by four motion regimes. While the spatial coupler link is considered to have distributed mass and elasticity, the clutch model neglects the masses of the sprags and represents the total clutch elasticity by way of a single, non-linear, massless torsional spring. The derivation of the equations of motion of the coupler and the feed-roller driven metal strip, for the various regimes, is based on Hamilton's principle. The subsequent application of the method of Kantorovich, wherein the space portions of the coupler motion are expressed in terms of its in and out-of-plane free-vibration modes, makes it possible to obtain coupled ordinary differential equations for the feed-roller motion, as well as the time portions of the coupler deflections. Part II presents numerical solutions of the model together with a confirming experiment.