Patent GB-1067589-A (GB)
Title: Device for stacking and re-separating flat articles, such as items of mail
IPC: B07C1/02
Filed: 1964-08-04
Abstract: 1,067,589. Feeding and stacking sheets. TELEFUNKEN PATENTVERWERTUNGS G.m.b.H. Aug. 4, 1964 [Aug. 2, 1963], No. 30790/64. Headings B6B and B6H. In apparatus wherein letters or other flat items of mail are stacked on edge on a moving belt and moved towards separating means, and the stack is replenished continuously by feeding the letters &c. between a movable pusher carriage and the end of the stack, the carriage is normally driven forward whenever the belt is driven, and is controlled by a sensing member on the carriage which senses the pressure of the carriage on the stack and responds to cause backward movement of the carriage when the pressure exceeds a predetermined value. As shown in plan in Fig. 1, a horizontal belt 1 supported on rollers 2, 3 is adapted to support a stack of letters (not shown) on edge and move it towards a separator comprising a suction belt 26 arranged on pulleys 27, 28. Guide rails 15, 16 support a carriage 17 provided with rollers 18, and letters are fed through a slot 19 in the carriage to replenish the stack on the belt 1, the stacking being facilitated by a roller 22. A motor 11 drives the roller 2 by a chain drive 9 to feed the belt 1 and a chain 14 is driven from the roller 2 at a higher speed than the belt 1 and is supported on an idler wheel 13 on the roller 3. A motor 20 on the carriage 19 has a shaft carrying a chain wheel 21 which engages the chain 14: thus, when the belt 1 is driven, the carriage 17 moves in the same direction at higher speed; but when the motor 20 is driven, the carriage 17 is moved backward due to the engagement of the wheel 21 with the chain 14. The motor 20 is controlled by a switch 25 which is operated when the pressure between the end of the letter stack and a sensing lever 24 on the carriage exceeds a predetermined value as the result of letters being fed to the stack quicker than they are being separated by the suction belt 26. When the letter stack presses against the suction belt 26 above a predetermined pressure, it causes a sensing lever 30 to operate a switch 31 to stop the motor 11. When the motor 11 and belt 1, are at rest, and letters are being fed through the slot 19 for stacking on the belt 1, the carriage 17 moves backward more or less continuously, controlled by the switch 25. In a modification (Fig. 3, not shown), the motor 20 is not mounted on the carriage, the latter is secured to the chain 14, and the two motors 11, 20 are aligned, driven in opposite directions, and coupled to a differential gearing having an output shaft arranged to drive the chain 14. When the motor 20 is switched off, the chain 14 is driven through the differential to drive the belt 1 and also the carriage 17, the latter travelling faster than the belt; but when this motor 20 is switched on by the switch 25, the drive speeds of the two motors are superimposed on one another, so that the carriage is driven at the resultant value of the two speeds, and may be driven more slowly than the belt 1, or even travel in the opposite direction. Brake motors may be used in both the above constructions. In a further modification shown in Fig. 5, the carriage 17 is attached to the chain 14 which can be driven in either direction by a reversible motor 20<SP>11</SP> connected to a three-phase supply line, and the belt 1 is driven by a motor 11<SP>11</SP>, both motors and switches therefor being arranged in a circuit in which relays automatically ensure the sequence of operations. The motor 11<SP>11</SP>, which only drives the belt 1 when the separator suction belt 26 is operating, is set in motion simultaneously with the motor 20<SP>11</SP> by operating a single manual switch, and the belt 1 and carriage 17 move in the same direction. The motor 11<SP>11</SP> is stopped when the pressure switch 31<SP>11</SP> is closed due to the stack pressing too heavily on the suction belt 26. The direction of rotation of the motor 20<SP>11</SP> is reversed if the switch 25<SP>11</SP> is closed due to the excessive pressure between the end of the stack on the sensing lever 24 on the carriage.