Abstract: Sheets of material and more particularly irregularly shaped sheets, such as hides, fabric or plastic, are stacked on a platform by a structure which is positioned above the platform and to which the sheets are fed by a conveyor, into a pair of rollers which are pressed together to grip a sheet at the front edge of the sheet and drag it to the rear of the structure and release it onto a stack of sheets on the platform. The structure has a single continuous drive which carries the rollers and cams for closing and separating the rollers to grab and release the sheets at preselected points along the structure so that the sheets are laid one after another as they come up the conveyor in a stack on the platform.