Patent Publication Number: US-7210597-B2

Title: Box-like container for flat mailings

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   The present application is a continuation of international application PCT/DE03/02500, filed on Jul. 24, 2003, which designated the United States and was pending at the time of designation and the filing of the present application; and further claims priority to German patent application 10234516.3, filed Jul. 30, 2002; the both of which are herein incorporated by reference. 

   BACKGROUND OF THE INVENTION 
   The invention relates to a box-like container for flat mailings in an upright position, having a stack support that can be removed from the container open at the top, and having a base, two narrow end walls and two lateral longitudinal walls. The mailings are aligned in the container with their large sides toward the end walls. 
   Modern letter sorting systems reach peak throughputs of up to approx. 45,000 mailings per hour. Emptying is generally carried out manually, that is to say the sorted stacks of mailings are transferred from the sorter into mail containers by hand. The mail containers themselves are then either stacked manually on trolleys or transferred to modern tray management systems. This manual process is associated with a high error rate of the operator, a high monotonous loading on the operator and very low throughputs. 
   When the mailings are fed into the sorter, there is generally likewise a manual transfer from containers to the separating apparatus of the sorter. 
   A further increase in output would therefore require additional operating personnel and therefore reduce the profitability of the sorting system. 
   In EP 0 109 325, FR 2 621 297, mail containers needed for this purpose are described. These consist of plastic (PP) and have various reinforcements in order to achieve the necessary dimensional stability. These containers are shaped in such a way that, given mutual alignment with one another and with an alignment rotated through 180° about the vertical axis in relation to one another, they can be stacked in one another. 
   In this connection, a container that is suitable for flat mailings in an upright position has been disclosed (DE 89 13 760 U1), whose inner sides of the lateral longitudinal walls have elongated recesses open at the top and running in straight lines at regular intervals at right angles to the base for a removable stack support which, in the longitudinal direction of the lateral longitudinal walls, are wider than their slot-like openings toward the interior of the container. At its two lateral ends, the stack support has shaped elements which can be pushed into the elongated recesses through the slot-like openings with a form-fitting connection only at right angles to the base. These recesses are wider in the longitudinal direction of the lateral longitudinal walls than their slot-like openings. In U.S. Pat. No. 3,200,983, the recesses are formed as dovetail guides. 
   For further increases in throughput, the development of automatic filling and emptying machines and the mail transport containers suitable for this purpose are required. 
   For this purpose, what is known as the mail cartridge system (MCS) is known (U.S. Pat. No. 6,026,967, WO 97/36523), in which use is made of a specific container which, itself formed as a stacking compartment, is suspended directly on the sorter in front of the stacking mechanism. The sorting is carried out directly in the cartridge-like container without a transfer process. After the sorting process has been completed, the cartridge is removed by a robot on the sorter, replaced by an empty cartridge and transferred to a buffer or transport system. The disadvantages inherent to the MCS system are, firstly, the complex and heavy cartridge, on account of the high functional integration, the considerably increased transport costs, the lack of any ability to be stacked and nested, restricted suitability for air freight and, secondly, the low filling rates of the containers. These cannot subsequently be filled with mailed goods. 
   The invention is based on the object of providing a box-like container having a removal stack support in order to hold and to transport flat mailings, in which, in spite of side walls with a low rigidity, secure retention of the stack support absorbing the stacking pressure is ensured in various positions corresponding to the stack size, and which prevents uncontrolled slippage of the mailings at right angles to the stacking direction. 
   SUMMARY OF THE INVENTION 
   According to the invention, the object is achieved by the features of claim  1 . 
   The inner sides of the lateral longitudinal walls of the containers have elongated recesses open at the top and running in straight lines at regular intervals at right angles to the base which, in the longitudinal direction of the lateral longitudinal walls, are wider than their slot-like openings toward the interior of the container. At its two lateral ends, the stack support has shaped elements which can be pushed in the elongated recesses through the slot-like openings with a form-fitting connection only at right angles to the base. The stack support is therefore introduced from above with its shaped elements into two opposite recesses and pushed downward as far as the base. In the process, the recesses are chosen such that the respective stack or part stack is kept under a specific stacking pressure. 
   There are longitudinal ribs in the base of the container. On the longitudinal ribs, the mailings can easily be displaced in the container longitudinal direction, which is necessary when joining two part stacks together or in order to produce a specific stacking pressure. Since mailings of different formats are transported in the container, slippage of the smaller mailings at right angles to the stack direction during transport is to be avoided in order that the necessary stacking pattern is maintained for further processing. This is achieved in that the heights of the longitudinal ribs decrease from the lateral longitudinal walls toward the center of the container. As a result, the mailings tilt toward the center over the longitudinal rib closest to the container side wall and remain caught by their leading edges on the next longitudinal rib, by which means displacement is prevented. 
   In the base of the container, at the spacing of the recesses, there are transverse ribs subdivided into partial transverse ribs by the longitudinal ribs. On the partial transverse ribs, the stack support pushed completely into the container and having cutouts for the longitudinal ribs is additionally supported against the stacking pressure in the recesses in addition to the lateral guidance, as result of which the bending stress acting on the stack support is reduced. 
   Advantageous refinements of the invention are presented in the subclaims. 
   In order that a stack support consisting of plastic (PP) has the necessary rigidity and the fabrication costs are kept low, it is advantageous for this to be of double-walled design and, on each side, to provide two shaped elements at the spacing from one another of the recesses of the container wall, said shaped elements being angled away from one another at their ends. 
   The partial transverse ribs advantageously have a sawtooth-like profile, whose tooth tips are formed by the upper edges of the longitudinal ribs. The steep tooth flanks are oriented toward the longitudinal walls of the container. 
   If the container is designed in such a way that a plurality of containers can be stacked on one another, given the same alignment, and, given a mutual alignment rotated through 180° about the vertical axis, can be stacked partly in one another, then the stack support is advantageously designed to be only so high that it does not touch the base of the respective upper container when they are stacked in one another. As a result, the stack support can remain in a secure captive position. 
   In order to permit an automatic loading and unloading sequence, the stack support advantageously has two handle receptacles, which can be centered, for machine handling. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The invention will be explained in more detail in the following text in an exemplary embodiment and using the drawings, in which: 
       FIG. 1  shows a perspective illustration of a container for flat mailings without stack support; 
       FIG. 2  shows a view of a section through the container parallel to the end wall; 
       FIG. 3  shows a perspective illustration of the stack support; 
       FIG. 4  shows a perspective illustration of a detail of the container with a view of and into the recesses of a lateral longitudinal wall. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In  FIG. 1  a container according to the invention is illustrated without inserted stack support. It has two end walls  1 , two lateral longitudinal walls  2  having elongated recesses  3  open at the top and running in straight lines at right angles to the base  6  on the insides. The side walls  1 ,  2  have no reinforcements and, in the upper part, are offset outward somewhat in order to permit stacking in one another. In the end walls there are two handles  4  for manual transport and stacking means  5 , which are arranged and designed in such a way that, given the same orientation, the containers stand on one another (the upper container does not dip into the lower container) and, given a mutual alignment the containers rotated through 180° about the vertical axis, the respective upper container dips into the lower container, depending on the height of the outwardly offset part of the side walls  1 ,  2 . As can be seen, the mailings  9  are parallel to the end walls  1 . In the base  6 , there are longitudinal ribs  7  running parallel to the lateral longitudinal walls  2 . 
   The height of the longitudinal ribs  7  decreases from the longitudinal walls  2  toward the center. As a result, the mailings  9  tilt over inward and each mailing  9  remains caught on the respective next longitudinal rib  7 , since the longitudinal ribs  7  become higher again beyond the center of the container. 
   This process can be seen particularly well in  FIG. 2 . Between the longitudinal ribs  7 , at the spacing of the recesses  3 , there are partial transverse ribs  8 , which have a sawtooth-like profile whose tooth peaks are formed by the upper edge of the longitudinal ribs  7 . The steep tooth flanks are aimed at the longitudinal wall  2  toward which the mailings  9  are to be oriented, that is to say toward the right-hand longitudinal wall  2 . The formation of the stack support  10  can be gathered from  FIG. 3 . As can be seen, it is of double-walled design, in order to increase the flexural rigidity. In order to increase the rigidity further, there are ribs  14  on the longitudinal surfaces. The stack support  10  is designed identically at the top and bottom so that, given an automatic sequence of the loading and unloading of the container, no attention has to be paid to the orientation of the stack support  10 . In order that the stack support  10  can be pushed as far as the base  6  of the container, the upper and lower sides have cutouts  11  for the longitudinal ribs  7 . Furthermore, there are on both sides handle receptacles  12  which can be centered for machine handling. At the lateral ends, the stack supports  10  have on each side two shaped elements  13  in the extension of the two walls and at the spacing of the recesses  3  of the container wall from one another, which are angled away from one another at their ends. The two shaped elements  13  on each side are therefore guided in adjacent recesses  3 . 
   This is illustrated particularly well in  FIG. 4 . Each recess  3  open at the top has a rectangular cross section, there being a gap oriented at right angles to the base in the termination oriented toward the interior of the container. It is also readily possible to see the longitudinal ribs  7  running parallel to the lateral longitudinal walls  2  and the partial transverse ribs  8 , which are arranged flush with the edge of the gap oriented toward the viewer. 
   Since the shaped elements  13  represent an extension of the walls of the stack support  10  with an angled-over portion, it is ensured that the lower part of the stack support  10  is also guided without relatively great play counter to the stacking pressure. It is also possible to see from above the prism-shaped handle receptacle  12 , which ensures a defined position of the handle in the stack support  10 .