Abstract: A feeder is acted upon by opposing hydraulic drives and a spindle drive limits the advance. Hydraulic buffers are interposed either between the spindles and the feeder or between a carriage carrying the spindle drive and the machine bed. The buffer biasing force exceeds the force exerted by the feeder advance upon the feeder. The rate of buffer response is tracked separately.

Abstract: A hold down device is disclosed suitable for an edge planing machine for working sheet metal. The hold down device has a plurality of hold down elements arranged in the direction of movement of the sheet metal and in a laterally overlapping relation. A plurality of piston cylinder units are provided and a single hydraulic cylinder is associated with and connected to each element for pressing it down against the sheet metal to be worked. The lateral surfaces of the elements facing the plate edge are in alignment with each other. The piston rod of the hydraulic drives are connected to the middle of each element for swivel action. The individual elements may either have an essentially rhomboidal or Z-shaped plan view. A further improvement adds spring forces and guidance to the hold down action.