Patent Publication Number: US-6908080-B2

Title: Device for forming and conveying away a sheet stack with the aid of a separating mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the priority of German Patent Application No. 102 08 309.6 filed Feb. 27, 2002. The disclosures of the foregoing priority application and of each and every U.S. and foreign patent and patent application mentioned herein are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   The invention relates to a separating mechanism for use with a device for forming sheet stacks in a stack repository and conveying the sheet stacks away from the stack repository. The separating device includes a sheet feeding device and a separating mechanism that can be introduced into the stack repository while the sheet stack is conveyed away. 
   A device for forming and conveying away sheet stacks is known from German patent document DE 198 49 859 A1. With this device, sheets are conveyed with a conveying track into a stack repository. While using a stack withdrawing device to remove the sheet stack from the stack repository, a separating rake is moved synchronously with a withdrawing movement of the stack withdrawing device in the transport direction of the removed sheet stack. The separating rake has an essentially horizontal platform, such that the sheets supplied continuously to the stack repository are deposited on the platform during the removal of a sheet stack. 
   SUMMARY OF THE INVENTION 
   In a device for forming and conveying sheet stacks, while a stack is conveyed out of a stack repository adjacent a sheet feeding device, subsequently supplied sheets are deposited on a belt element moved into the stack repository during the removal of a sheet stack. The belt element is moved into the repository such that continuously supplied sheets are collected horizontally in the stack repository. The belt element positioned inside the stack repository is tensioned or rigid enough such that the supplied sheets rest essentially horizontally on the belt element. 
   The belt element of the present invention results in a simplified design of the device. 
   In an exemplary embodiment, the belt element is flexible. For example, if the belt element for the sheet repository is not in use, it can be easily stored inside the device, for example, by rolling up the belt element. As a result, the space required for the belt element inside the device can be limited to a minimum. In addition, the belt element can be redirected from a vertical to a horizontal direction and vice versa because of its flexibility to result in further space-saving advantages. 
   One advantageous modification of the invention provides a belt element section of the belt element with a bending elasticity. The belt element and/or the belt element section can reliably pick up and carry the supplied sheets. The bending elasticity of the belt element and/or the belt element section is such that the subsequently arriving sheets for the next ream or stack are separated and supported. Moreover, the belt element and/or the belt element section can be easily installed in a space-saving manner inside the device. 
   The belt element can be a steel belt. 
   At least one guiding device for the belt element is optionally provided, for example, for moving the belt element securely into the stack repository. 
   In addition, the height of the guiding device is optionally adjustable to ensure that the sheets supplied in a scaled formation are always dropped from the same height while forming a new stack and during the stack replacement. 
   The belt element can be moved in a reliable and controlled manner into the stack repository by at least one drive provided for the belt element. 
   The drive can optionally be a motorized or pneumatic drive. 
   The belt element can optionally be introduced in a sheet transporting direction into the stack repository. 
   According to one advantageous modification of the invention, the belt element optionally moves synchronously with the withdrawing movement of a stack-withdrawing device. 
   A separating hook is provided at the stack repository to ensure a secure stack formation. The separating hook causes a finished ream to be separated from the subsequently delivered sheets. 
   In one embodiment, the separating hook is arranged opposite the sheet feeding device. 
   In an exemplary embodiment, a separating mechanism is utilized in a device for forming sheet stacks in a stack repository and/or for conveying sheet stacks away from a stack repository. The device includes a sheet feeding device and a separating mechanism that can be moved into the stack repository while a sheet stack is conveyed away. Optionally, the separating mechanism is embodied as a belt element. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is explained with the aid of the drawings which show at least one exemplary embodiment without restricting the general inventive idea. 
       FIGS. 1   a  to  1   d  are side views of the device of the present invention in various operating positions. 
       FIG. 2  is a cross-sectional view of a guiding device for a belt element used in the device of  FIGS. 1   a - 1   d.    
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Identical or corresponding parts are given the same reference numerals in the drawings and may not be introduced again. 
   As shown in  FIGS. 1   a - 1   d , a device repository for gathering paper sheets  2  into sheet stacks  3  includes a stack repository  1 . The stack is divided into numerous collection boxes  4  arranged one behind the other perpendicular to the drawing plane. Relative to the sheet and/or stack conveying direction, referenced as arrow  6 , the collection box  4  is supplied in an upstream direction by a conveying track  7 , embodied as a belt track in one exemplary embodiment. The track  7  supplies the paper sheets  2  in a scaled formation. In a downstream direction, the collection box  4  is provided with a stack withdrawing device  8 , embodied as tong-like gripper  5  in one exemplary embodiment, and a subsequent transverse conveying arrangement (not shown herein) that can include up and down moving conveying belts and integrated air-table segments. 
   The stack repository  1  is delimited by several stack limiting stops  13  and rear stack limiting stops  14 . The first limiting stops can pivot from the operating position shown in  FIG. 1   b  into a non-operating position shown in  FIG. 1   a . As also shown in  FIG. 1   b , a separating hook  12  can be arranged on the stack limiting device  13  opposite the sheet feeding device to support the leading sheets of a new stack while a completed stack is removed. 
   The rear stack limiting stops  14  are mounted on a slide  16 . The transport track  7  is also arranged on the slide  16 , which can be displaced in the direction of double arrow  15 . In a region adjacent the rear stack limit stop  14 , the slide  16  is provided with a guide element and/or a guiding device (see  FIG. 2 ) that enables a belt element  17 , arranged on and/or inside the slide, to move into the stack repository. Sheets are dropped from one end  18  of transport track  7  at a defined distance to the guide for the belt element  17 . The slide  16 , in turn, is arranged to be displaceable on a slide carrier  21  that can be adjusted in height, as shown by double arrow  19 . 
   The collection box  4  has a bottom platform  22 . The bottom platform  22  can be provided as a complete replacement group with format-dependent, pre-adjusted side limit stops for particular stack characteristics. 
   A description of the operation of the device is described below. As shown in  FIG. 1   a , a sheet stack  3  is formed by a defined number of gathered paper sheets  2 . The front stack limit stop  13  is pivoted away, and the stack is gripped by the tong-like gripper  5  of the stack withdrawing device  8 . The stack is then transferred in conveying direction  6  away from the stack repository  1  and onto a crossover conveying arrangement. As shown in  FIG. 1   b , the conveying arrangement then optionally removes the sheet stack in the directions indicated with arrow symbols  29  and/or  31 , which are perpendicular to the drawing plane. 
   Synchronously with the transfer movement of the stack withdrawal device  8 , the belt section  17   a  of belt  17  is optionally moved into the region of the stack repository  1  until it is stopped by the stack limiting stop  13  which has again moved back into the limiting stop position. In the process, the paper sheets  2  that are supplied in a scaled formation are simultaneously transferred without interruption onto the horizontal, rigid belt section  17   a.    
   By moving the slide carrier  21  downward in the direction of double arrow  19 , as shown in  FIG. 1   c , the section  17   a  of belt  17  is lowered to or below the bottom platform  22  of the stack repository  1 . As shown in  FIG. 1   d , the belt section  17   a  is pulled back from the stack repository  1  into the starting position such that the newly forming sheet stack  3  can be supported by the bottom platform  22 . The belt element  17  in this case is pulled back with the aid of a motor  23 , which is also arranged on the slide  16 . The belt element  17  for the exemplary embodiment shown herein is at least partially arranged vertically. When moving the flexible belt  17  into the stack repository  1 , a rigid section is formed in the belt itself such that a sheet stack is formed by horizontally deposited and stacked sheets. 
   As a result of the subsequent upward movement of the slide carrier  21  in the direction of double arrow  19 , the conveying track end  18  from which the sheets are dropped is lifted up to match the increase in the height of sheet stack  3  in order to ensure a uniform paper drop height. 
     FIG. 2  shows a vertically displaceable guiding device  25  for the belt element  17 . The belt element  17  section on the side of the slide is guided vertically, then bent and redirected by 90° with the aid of rollers  26  of the guiding device  25  such that the belt element section  17   a  can essentially be pushed horizontally into the stack repository  1 . To ensure a secure guidance of the belt element section  17   a , upper and lower holding elements  27  with an opening  28  are provided near the rear stack limit stop  14 . 
   The invention has been described in detail with respect to exemplary embodiments, and it will now be apparent from the foregoing to those skilled in the art, that changes and modifications may be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the appended claims, is intended to cover all such changes and modifications that fall within the true spirit of the invention.