Apparatus for stacking letter mail

An apparatus for stacking letter mail side by side in the upright state in a stacking position in a stacking section, said apparatus comprising:

• a letter mail supply path extending toward said stacking section through which the letter mail is supplied;
• letter mail supply means for supplying pieces of letter mail one by one in the upright state through said letter mail supply path;
• letter mail supporting means provided with a surface for supporting the bottom of the letter mail stacked in said stacking section on the surface;
• holding means connected to said letter mail supply path for holding the stacked letter mail, and including a forcible feeding means for engaging the forward end portion of each piece of the letter mail supplied from said letter mail supply path and for forcibly feeding said piece to the stacking position, and urging means for urging a rear end portion of the piece of the letter mail;
• and
• a movable back-up means facing said holding means for co-operating with said holding means to sandwich the stacked letter mail between said holding means and movable back-up means,
• said urging means including
• a lever means which is pivotally supported on the holding means side of the supply path, and movable between an advanced position in which the free end of the lever is located in the stacking section and capable of pushing the rear end portion of the letter mail against the movable back-up means, and a retracted position in which said lever means is separated from the supply path such that the next piece of the letter mail can be supplied along the supply path,
• detecting means provided along the supply path at a location upstream of said lever means with respect to the feeding direction of the letter mail, said detecting means for detecting the forward end of the letter mail which has passed through the detecting means, and
• driving means for keeping the lever means in the advanced position when the detecting means does not detect the letter mail, and for moving the lever means from the advanced position to the retracted position during a given time until the forward end of the piece of the letter mail passes beyond the lever means when the detecting means detects the forward end portion of the piece of the letter mail.