Method and device for stacking flat mail items

A method for stacking flat mail items, whereby

• the mail items are transported with a transport means in turn into stackers and are stacked in a vertical position in these,
• in each stacker at a stacking point a mail item to be stacked is transported by means of a stacking roll which can be displaced from a stack against a spring pressure, which is controlled to be driven in a start-braking mode, against a stop wall, and a controlled driven underfloor belt and a stacking support coupled so that it can be released from this or driven separately is moved away from the stacking point as the stack grows,
• the mail item to be added to the stack in each case arrives at an acute angle to the previous, already stacked mail item,
• before the stacking the mass of each mail item to be stacked is determined,
• stacking pressures are measured with a measuring device arranged in an area of the stacking roll in a mail item transport plane or on the stacking roll itself, if the stacking roll has engaged with the mail item to be stacked,
• in a preceding test phase based on statistical investigations the target values for the stacking pressures and braking curves of the stacking roll until the mail items have reached the stop wall are defined as a function of the mass of the respective mail items to be stacked and stored,
• the respective mail item is braked in accordance with the braking curve of the stacking roll assigned to the mail item mass.