The present invention relates to an input unit of a letter sorting system including a mail or letter isolating device connected to a mail conveyor line and oriented horizontally with a supporting wall. Relatively flat mail pieces are transported, with the assistance of separation blades, to the isolating device. The mail pieces are standing on edge. The separation blades may be made to swivel into a stack of mail pieces in facilitating transport of a select portion of the stack as well as provide support therefor. The separation blades further run on linear guides which facilitate linear transport of a select stack portion.
To date, input units are loaded manually. This is a rather expensive undertaking. Herein, mail pieces are dumped from a mail container of a mail conveyor line, or manually removed stack-wise from the mail container, and put on the mail conveyor line. Thereafter, the mail pieces are moved, again by hand, along a supporting base and oriented sidewise against a supporting wall and to the mail isolating device. The separating blade is then swiveled in behind the stack and mail separation or isolation starts. The separating blade and additionally the optional mail conveyor line, which is executed as conveyor coupled with the separating blade, supplies the stack in a pressure-controlled manner to the isolating device.
EP 0865328 B1 sets out an installation for an automatic loading of an input unit of a letter sorting system without manual input. A loaded container is thereby emptied by a loading module on the mail conveyor line of the input unit between two additional, moveable and swiveling separating blades. Then the stack is automatically moved to the remaining stack by the two separating blades in a direction of the mail isolating device. The separating blade, which supports the remaining stack, extends, advances closely behind the additional rear separating blade, swivels in again and the two additional separating blades swivel out and advance to the back for the capture of a new stack. With this solution too, the mail pieces get to the input unit in a mail container, i.e. the mail pieces have to be loaded in the mail containers in a relatively expensive manner. These mail pieces come in many cases from pre-arranged sorting machines. Then the pre-sorted mail pieces are loaded from the respective sorting bins into the mail containers and, as described, transported to the corresponding input unit.
There are also sorting processes with several successive sorting runs, where the mail pieces from the sorting bins are not loaded into the mail containers, but moved by a transfer bridge from the sorting bins on the mail conveyor line of the input unit (see e.g. DE 42 36 507 C1). For this, a certain machine layout is necessary where the sorting bins and the mail conveyor line of the input unit are opposing.