Patent Publication Number: US-6336782-B1

Title: Method and device for unloading sheet-like objects from containers

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a method and a device for unloading sheet-like items, stacked one above the other with their flat sides, in particular letters, from box-shaped containers that are open on the top into a v-shaped receiving device. 
     Up to now, postal items and in particular large envelopes have always been delivered to a letter-sorting machine such that the items are stacked flat one above the other in box-shaped containers, each with an open top. An operator then removes the postal items from the containers and places these into a v-shaped receiving device, after which they are handled automatically. 
     European Patent A-464771 additionally discloses a solution using a container tilting device where the operator no longer must lift the postal items from the container, but must push them from the tilted container onto the receiving device. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to create a device and a method for automatically placing the sheet-like items, arriving flatly stacked in the container, into an upright position for sorting in the transfer device. 
     For a method of the aforementioned type, this object is solved according to the invention in that the containers are respectively inserted into a holding device and the opening of the respective container is subsequently closed off with a plunger. Following this, the closed holding device is swung with one side wall approximately aligned against one of the flanks of the receiving device, thereby overlapping this flank, wherein the closed opening is facing the v-shaped bottom of the receiving device. The plunger is then removed from the items and is swung to the side, such that the items slide into the receiving device. 
     The aforementioned object is furthermore solved according to the invention for a device of the initially mentioned type in that the individual containers can be inserted into a holding device and the opening of the respective container can be closed off with a plunger. The closed holding device can subsequently be swung with one side wall approximately aligned against one of the flanks of the receiving device, thereby overlapping this flank, wherein the closed opening is facing the v-shaped bottom of the receiving device, such that the plunger can be lifted off the items and swung to the side and the items can slide into the receiving device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     One exemplary embodiment of the invention is shown in the drawing and is explained in further detail in the following, wherein: 
     FIGS. 1 to  4  Show successive situations during the automated handling. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     The basic diagram shown in FIG. 1 illustrates how a container B for postal items G is inserted from a loading plane BN into a holding device HV. The insertion movement, which is directed toward the representational plane, is indicated with a crossed circle. The container B in the inserted state is secured in the holding device HV with auxiliary means, not shown herein for reasons of clarity. The container B, which is then secured immovably in the holding device HV, is open on the top. A plunger S is located to the side of holding device HV. The purpose of this plunger will be discussed further in the following since it is extremely important to the invention. 
     A tub-shaped receiving device A for postal items, in particular for large envelopes, is arranged above the holding device HV. The receiving device A has a v-shape alignment and is designed to accept the flatly stacked items G such that they are standing on edge. 
     The illustration according to FIG. 2 shows that by executing a swinging movement, as indicated with an arrow, the plunger S is pressed against the postal items G, thereby covering the tub-shaped container B. 
     Following this, the holding device HV with secured container B and postal items G located therein is swung upward, as indicated with the arrow in FIG.  3 . The pressed-on plunger S prevents the postal items G from falling out of the container B. The holding device HV is in this way moved toward the receiving device A, so as to prepare for an independent removal of the postal items G, as indicated in the illustration according to FIG.  4 . The arrow in this Figure furthermore shows that the plunger S is lifted off the postal items G, wherein the items G slide into the tub-shaped receiving device A. For this, the plunger S is also pulled off to the side. 
     From this position, the holding device HV can move the containers into an unloading plane, which does not necessarily have to coincide with the loading plane BN where containers are again released from the holding device HV into the process. Following this, the holding device HV is once more available for accepting new containers. 
     In principle, the receiving device A for postal items G can be arranged stationary. However, it is also possible that the receiving device A is moved to downstream transfer positions by another mechanism, which is not shown for reasons of clarity.