Document advancing machine

1,031,828. Feeding sheets. SPERRY RAND CORPORATION. May 7, 1964 [May 20, 1963], No. 18960/64. Heading B6B. In a machine such as a document sorter wherein documents 30 are separated sequentially from a stack 32 and fed along a path to various containers 68, 70, the documents are separated by a suction separator 48, Fig. 1, a suction restrainer 50 adjacent the stack substantially ensures that only one document at a time is separated, and a suction operated detector 82 indicates when more than one document is separated, the separator, restrainer, and detector being connected to a common vacuum system which has provision for minimizing pressure fluctuations comprising a mechanically operated relief valve in the separator 48, primary and secondary chambers in the restrainer 50 interconnecting by a nozzle which does not form an air-tight connection between them, and an air pipe leading from the secondary chamber to the detector 82. Pile supports.-Documents 30 stacked on edge and inclined, Figs. 1 and 19, in a tray 32 are advanced by a back-plate 34 which has rollers engaging a rail 36 and is secured to an endless chain 40 driven continuously. The speed of the drive mechanism is varied by a pivoted feeler 44 which engages the front document of the stack and controls the flux in a transformer 278 in the circuit of the drive mechanism. Sheet separators.-The suction separator 48, Figs. 1, 13, and 19, comprises two elbow-shaped tubes 104, 108 slidable on each other, the tube 108 also being rotatably mounted in a flange 110 which communicates with the vacuum system. The separator 48 is adapted to be swung about the vertical axis of the flange 110, and the tube 104 is given simultaneous sliding movement within the tube 108, such that the operative suction face on the tube 104 performs a substantially D-shaped path (Fig. 15, not shown) to feed forward the front document 30 of the stack. The tube 104 is bifurcated to provide two separate heads having flat suction faces 134, 136 in which wires &c. are inset to prevent undue bulging of the documents; in each suction head there is a valve (114, not shown) which normally fits within a removed portion of the head, and both valves are operated automatically by the engagement of a follower arm 126 on the tube 104 with a fixed cam track 124 on the tube 108 when there is relative sliding movement between those tubes. Thus, when a document 30 is grasped, the subsequent movements of the separator 48 cause the valves in the suction heads to open, to allow air to enter and prevent excessive suction being built up, and thus provide a more even flow of air through the vacuum system. The movements of the separator 48 are obtained from a gear-driven flywheel 224, Fig. 13, which drives a controlled crank system 232, 236 which actuates a rod 160 mounted on the tube 104. The front document 30 cannot be separated from the stack until an electromechanical actuator 56 raises an arm which is pressed against that document. Air blasts are directed from above and below the top documents to assist separation. The means to restrain the separation of more than one document 30 from the stack by the separator 48 comprises a primary air chamber 50 which has one face engaging the stack, Fig. 1, and a top face which forms a suction head over which the documents pass. The air intake through the head is divided into two passages to facilitate better retention of the second document, and a grating covers both passages. The other end of the chamber 50 is fitted with an adjustable nozzle situated within the throat of a secondary air chamber 52 which is connected.to the vacuum system. Atmospheric air can enter the chamber 52 around the nozzle of the chamber 50 to prevent excessive suction being established in the system. A pipe arranged in the chamber 52 near the throat thereof is connected to the multiple document detector 82. To remove the document 30 initially displaced from the stack by the separator 48, a timing cam roller 76 is actuated to press the front end of the documents into engagement with a travelling endless belt 61. Sheet forwarders.-The separated documents 30 are fed between a pair of endless belts 60, 61 and a number of auxiliary belts to containers such as 68, 70, the particular container being determined by a magnetic reading head 84 and photo-electric device 86, 88 substantially as described in Application No. 20421/62. The front end of a document is first urged against the belt 61 by a reciprocating pulley 76 controlled by a timing mechanism 226, Fig. 13, and is then moved between the two belts 60, 61. Multiple feed detection.-The detector 82, Figs. 1 and 10, is a hollow casing formed by two U-shaped members 190, 192 connected by an air pipe 122 to the secondary chamber 52 of the document restrainer 50, and has a slot 196 which will receive two superposed documents 30. The inside of the casing is divided by spaced ribs 198, 200 enclosing an area 204 which has outlet nozzles 210, 212 leading to chambers 206, 208, and the area 204 is connected by an air pipe to a pressure switch (218, not shown). In operation, a single document 30 within the slot 196 will close off one of the chambers 206, 208, e.g. chamber 208, and an air path exists through the chamber 206, and the pipe 122 to the vacuum system; there is also a secondary air path through the chamber 204, and the pressure switch is adjusted so that it is not affected under these conditions. When there are two superposed documents 30 in the slot 196, both chambers 206, 208 are sealed off, there is a sudden rush of air from the chamber 204 through the nozzles 210, 212 into the chambers 206, 208, and this is detected by the pressure switch which acts to stop the feeding of documents, or to cause the two superposed documents to be fed to a reject container.