Abstract: A stacker for sheets, e.g. of cardboard or paper, is equipped with a device for inserting Marker strips or tabs within the stack to indicate predetermined numbers of sheets therein, e.g. for identification of reams. The inserter has a rigid channel Mounted on a frame moveable on a traverse transverse to the direction of sheet feed and the channel at its outlet is rigidly connected to a tongue having a substantially horizontal underside and moved with the outlet of the channel in a rectangular pattern with only vertical and horizontal path segments so that the tongue can be withdrawn from the stack without changing its orientation horizontally after a strip has been inserted into the gap formed by the tongue in the stack and alongside the tongue.

Abstract: A moveable skid is provided to sense the height of a pallet fed to a raisable and lowerable platform. The skid determines the height of the pallet before it is fed to a raisable and lowerable platform of a sheet stacking apparatus so that the position of the pallet below an intermediate stacking platform can be determined during the pallet change. This prevents adverse effects by nondetrimental projections above the surface of the pallet and prevents an excessive drop of the intermediate stack as it is transferred to the pallet.