Apparatus and method for separating flat articles

Abstract

In an apparatus for separating flat articles of a stack, operating elements of one side of a transport path are fastened on a sliding plate which, in the individual-separation state, is moved away from the transport path and back again and is driven in a controlled manner. In the event of a fault warning from a sensor set-up for determining fault states during the individual-separation process, transport elements moving the articles along the transport path are stopped, and the sliding plate is moved into an individual-separation position for opening the transport path and, after a short time, for re-closing the transport path. After closing of the transport path, the transport elements resume their transport operation.

1 . An apparatus for separating flat articles of a stack of articles when operated in an individual-separation mode, comprising:
 a plurality of transport elements for transporting the articles;   a drive for moving the transport elements;   at least one retention element for retaining the articles, wherein the transport elements and the retention element are configured to transport the articles in the individual-separation mode on a transport path through between the transport elements to individually separate the articles;   a mounting, wherein at least one of the transport elements and the retention element is fastened to the mounting, and wherein the mounting is configured to cause a movement of the mounting to vary a distance between the transport elements and the retention element;   a mounting drive for moving the mounting; and   a control unit for controlling the drive for moving transport elements and the mounting drive, wherein the control unit is configured:
 to interrupt the individual-separation mode and stop the transport element drive after the reception of a fault signal, 
 to subsequently activate the mounting drive to move the mounting to increase a distance between the transport elements and the retention element, 
 to subsequently activate the mounting drive to move the mounting to reduce the distance between the transport elements and the retention element, and 
 to shift the apparatus into the individual-separation mode and start the transport element drive. 
   
     
     
         2 . The apparatus of  claim 1 , wherein the control unit is configured to carry out the activation of the mounting drive for increasing the distance after expiry of a predetermined increase time span. 
     
     
         3 . The apparatus of  claim 1 , wherein the control unit is configured to carry out the activation of the mounting drive for increasing the distance after reception of a triggering event. 
     
     
         4 . The apparatus of  claim 2 , wherein the predetermined increase time span between the activation for increasing the distance and the activation for reducing the distance amounts to at least one and at most three seconds. 
     
     
         5 . The apparatus of  claim 1 , wherein the control unit is configured:
 to activate the transport element drive to move at least one transport element for a predetermined movement time span after the activation for decreasing the distance, and   to activate reducing the distance at the earliest after expiry of the movement time span.   
     
     
         6 . The apparatus of  claim 5 , wherein the predetermined movement time span amounts to at least 50 and at most 300 milliseconds. 
     
     
         7 . The apparatus of  claim 5 , wherein the articles move in the individual-separation mode in a transport direction, and wherein the control unit is configured to activate the transport element drive to cause a movement of the at least one transport element opposite to the transport direction in the movement time span. 
     
     
         8 . The apparatus of  claim 1 , wherein one of the transport elements and the retention element is arranged such that gravity moves the articles downward in the increase time span. 
     
     
         9 . The apparatus of  claim 8 , further comprising a conveyer band arranged to transport articles in the increase time span. 
     
     
         10 . The apparatus of  claim 1 , wherein the mounting is designed as a sliding plate. 
     
     
         11 . The apparatus of  claim 1 , wherein the control unit is configured:
 to count how often the control unit has caused activation for increasing the distance, and, if the control unit has carried out activation for increasing the distance a   predetermined number of times and a fault signal is present, to renew activation for increasing the distance and renew stopping of the transport element drive, and to shift the apparatus into the individual-separation mode only after reception of a fault elimination signal.   
     
     
         12 . The apparatus of  claim 1 , wherein the transport elements and the retention element are arranged such that, in the individual-separation mode, they act on the articles non-positively by means of frictional force. 
     
     
         13 . The apparatus of  claim 1 , further comprising at least one light barrier and an evaluation unit, wherein the evaluation unit is configured:
 to generate a fault signal when the light barrier is obscured for longer than a predetermined obscuring time span, and   to transmit the fault signal to the control unit.   
     
     
         14 . A method of separating flat articles of a stack, comprising:
 shifting an individual-separation apparatus with a plurality of driven transport elements and at least one retention element into an individual-separation mode;   transporting the articles on a transport path through between the transport elements and the retention element to individually separate the articles;   automatically transferring the apparatus out of the individual-separation mode into another mode after reception of a fault signal;   moving a driven mounting, on which the transport elements or the retention element are fastened, so that a distance between the transport elements and the retention element is increased;   moving, after expiry of a predetermined increase time span, the mounting so that the distance between the transport elements and the retention element is reduced; and   shifting the apparatus into the individual-separation mode and driving the transport elements.   
     
     
         15 . The method of  claim 14 , further comprising:
 after the increase in the distance, moving at least one transport element for a predetermined movement time span, and   carrying out the reduction in the distance at the earliest after expiry of the movement time span.   
     
     
         16 . The method of  claim 14 , further comprising:
 counting how often the distance has been increased, and,   when the increase in the distance has been carried out a predetermined number of times and a fault signal is present, increasing the distance once more, stopping the transport elements, and shifting the apparatus into the individual-separation mode again only when a fault elimination signal is received.