Device for feeding pieces of mail, especially unsealed pieces, from a stack and a method of operating the device

A method of operating a device for feeding flat pieces of mail from a stack, said method comprising supporting said stack of pieces of mail in edgewise abutment with a retention wall, feeding said pieces of mail off the stack by operating a feed device at a speed V.sub.1 perpendicular to the stack;

• transferring the pieces of mail fed off the stack by a transfer means at a speed V.sub.2 ;
• and disposing an anti double feed device between the feeding means and the transfer means, and wherein a plurality of detectors are located in the path of pieces of mail fed off the stack and comprising a first detector located between the retention wall and the retention device;
• a second detector located in proximity to the retention device;
• and a third detector located in line with a point at which the pieces of mail are entrained with the transfer means, and said method further comprises:
• 1) activating the means for feeding said pieces of mail off the stack and translating a piece of mail, with the retention device maintained out of action;
• 2) when the second detector detects a piece of mail, activating the retention device, after a delay, to ensure that the first piece of mail is taken hold of by the transfer means;
• and
• a) if the first detector does not detect a second piece of mail, reactivating the means for feeding said pieces of mail off the stack after a delay, and when the second detector no longer detects a piece of mail, deactivating the retention device and recommencing the cycle at point 2);
• b) if the first detector detects a second piece of mail, when the second detector no longer detects a piece of mail, deactivating the retention device and reactivating the means for feeding pieces of mail off the stack after a delay, and recommencing the cycle at point 2;
• c) if the first and second detectors detect a second piece of mail, when the third detector no longer detects the first piece of mail, deactivating the retention device and reactivating the means for feeding pieces of mail off the stack;
• when the third detector than detects the second mail piece, reactivating the retention device and deactivating the means for feeding pieces of mail off the stack and recommencing the cycle at point a), b) or c).