Method and an appliance for separating individual, flat, flexible products from the lower side of a stack

Abstract

A method and an associated appliance for the cyclically controlled separating and singularizing of flat, flexible products from the lower side of a stack of such products and for conveying the singularized products away from the stack. The method includes the: gripping the lowermost product of the stack, separating the lowermost product from the stack lower side and transporting the product away from the stack. A first process condition is detected within cycle-linked measuring time window and a second process condition is detected within at least one further cycle-linked measurement time window in the same work cycle, by way of a single sensor in combination with a control device.

1 . A method for the cyclically controlled separating and singularizing of flat, flexible products from the lower side of a stack of such products and for conveying the singularized products away from the stack, comprising the steps of:
 gripping the lowermost product of the stack,   separating the lowermost product from the stack lower side and   transporting the product away from the stack,   wherein a first process condition is detected within cycle-linked measuring time window and a second process condition is detected within at least one further cycle-linked measurement time window in the same work cycle, by way of a single sensor in combination with a control device.   
     
     
         2 . The method according to  claim 1 , wherein a third process condition is determined within a further cycle-linked measurement time window in the same work cycle. 
     
     
         3 . The method according to  claim 1 , wherein in the respective measurement time window, at least one measured value is determined by the sensor and evaluated by the control device, and an extraordinary process step is initiated in a temporally subsequent process course given a deviation of the determined measured value from a predefined set value. 
     
     
         4 . The method according to  claim 1 , wherein the sensor is an optical sensor for detecting a light signal. 
     
     
         5 . The method according to  claim 1 , wherein the sensor is part of a light barrier with a light signal source and in particular with at least one reflector. 
     
     
         6 . The method according to  claim 5 , wherein, from the measured values, it is determined whether the measuring beam path of the light signal has been interrupted between the light signal source and the sensor. 
     
     
         7 . The method according to  claim 5 , wherein a reflector is located in each case in the reflecting position for reflecting the light signal towards the sensor, within the respective measurement time window. 
     
     
         8 . The method according to  claim 1 , wherein within the measurement time window, it is examined whether the measuring beam path is interrupted by a product, which is correctly held by the transport element and moved through the measuring beam path. 
     
     
         9 . The method according to  claim 1 , wherein, within the further measurement time window, in which, with a correct operation, a product intermediate space between two consecutive products of two work cycles is moved through the measuring beam path, it is examined whether the measuring beam path is interrupted, in particular by a product that is not correctly separated from the stack. 
     
     
         10 . The method according to  claim 9 , wherein, within the further measurement time window, it is examined whether the measuring beam path is interrupted by a pulled-open, multi-page product or a surplus product. 
     
     
         11 . An appliance for the cyclically controlled separation and singularization of flat, flexible products from the lower side of a stack of such products and for conveying the singularized products away from the stack, with a control device for the cyclically controlled operation of the appliance,
 wherein the appliance comprises a sensor, which in combination with the control device, is designed for detecting a first process condition within a cycle-linked measurement time window and for detecting a second process condition with a further cycle-linked measurement time window in the same work cycle, for the purpose of detecting irregularities on separating and transporting away the products.   
     
     
         12 . The appliance according to  claim 11 , wherein the sensor is an optical sensor. 
     
     
         13 . The appliance according to  claim 12 , wherein the appliance comprises a light barrier with a light signal source, and the optical sensor is part of the light barrier for receiving a light signal emitted by the light signal source. 
     
     
         14 . The appliance according to  claim 12 , wherein the light barrier is a reflection light barrier which comprises at least one reflector for reflecting a light signal emitted by the light signal source, to the sensor. 
     
     
         15 . The appliance according to  claim 13 , wherein the light signal source comprises a laser diode. 
     
     
         16 . The appliance according to  claim 11 , wherein a transport device, by way of which the products are transported away from the stack, and the at least one reflector is arranged on a moved component of the transport device. 
     
     
         17 . The appliance according to  claim 13 , wherein the light signal source of the light barrier is arranged such that the measuring beam path of a light signal emitted by the light signal source is interrupted by the product with the away-transport, within the measurement time window. 
     
     
         18 . The appliance according to  claim 13 , wherein the light signal source of the light barrier is arranged such that the measuring beam path of a light signal emitted by the light signal source leads through the product intermediate space of two products within the further measurement time window. 
     
     
         19 . The appliance according to  claim 14 , wherein at least one reflector or reflector section is arranged in a manner such that given an empty cycle, the light signal is reflected from the reflector or reflector section to the sensor within the measurement time window. 
     
     
         20 . The appliance according to  claim 14 , wherein at least one reflector or reflector section is arranged in a manner such that on moving an intermediate product space through the measuring beam path, the light signal is reflected from the reflector or reflector section to the sensor within the further measurement time window.