Patent GB-939740-A (GB)
Title: A stacking device for the stacking of articles of mail
IPC: B07C1/02
Filed: 1961-01-16
Abstract: 939,740. Transmitting articles of mail. SIEMENS & HALSKE A.G. Jan. 16, 1961 [Jan. 14, 1960], No. 1814/61. Class 78 (1).  To compensate for an irregular flow of articles of mail along conveyer routes within post office automatic letter distributing installations, apparatus for the intermediate stacking of articles of mail is provided. As shown in Fig. 1, letters 10 are fed by rollers 13 into open-sided pockets 4 which are carried by an endless chain 2 engaging chain wheels 3 of a stacking device 1. The feeding of the letters is controlled by an electromagnet M3 which may control a latch 12 or the rollers 13. On the opposite side of the stacking device is a discharge station which comprises a belt unit 15 and a device 14 for extracting letters from the pockets 4. Circulation of the chain 2 and pockets 4 takes place when two chain wheels 7 engaging the chain are driven by a motor 5 operating through clutches 8 controlled by magnets M1, M2 and armatures 9. Additionally, by rotating one wheel 7 and maintaining the other wheel stationary, the stacking device may be made to move vertically up or down. In a modification shown in Figs. 2, 3, sensing means detect when a pocket is filled at the feeding station and when the letter level in a pocket at the discharge station has fallen to a pre-selected height. Letters at the feeding station are scanned by a photo-electric device L1/Pc as they are released by the latch 12 and contacts s, o, m and u are operated at points in the vertical displacement of the stacking device. Worm wheels S1, S2 drive the chain wheels 7 and contacts n1<SP>1</SP>, n1<SP>11</SP>, n2 are operated by earns driven by the chain wheels 7. A covering means, e.g. an endless belt, is arranged to fit against the underside of the pockets as they circulate between the feeding and discharge stations, so that letters are prevented from falling out. When the device is empty, switching on the installation causes the electron agents M1, M2 to be operated, both chain wheels are driven, and the pockets 4 circulate ; but no vertical displacement of the device takes place. When a pocket reaches the feeding station any letter which may have been held back by the latch 12 is released by actuation of the electromagnet M3 which is energized by closing of the contact n1<SP>1</SP>. Passage of the letter through the photoelectric sensing device L1/Pc interrupts the drive to the pockets 4 while the letter is fed into the pocket but the drive is restored until a further letter is ready for feeding to a pocket. The sequence continues until a pocket with a letter reaches a sensing level 16 at the discharge station and the sensing means causes the drive to the chain wheel 7 at the discharging side to be interrupted. If letters continue to be fed into the pockets, the device descends to the position shown in Fig. 5d, the contact u is opened and drive to the chain wheel 7 at the feeding side is stopped by de-energization of the electromagnet M1. When emptying the pockets, assuming the device to be in the position shown in Fig. 6a, and the level of the letters in the pocket being emptied falls below the pre-selected height, contact V2 will close and drive to the chain wheel on the discharge station is engaged. Since the other chain wheel is not driven, the device ascends, half a pocket width at a time, and discharge continues, Fig. 6b. When the device reaches the position, Fig. 6c, the contact at o is opened, the electromagnet M1 is de-energized and electromagnet M2 energized. The device then descends, the pockets circulate and all are completely emptied before the device returns to the position 5a. Simultaneous charging and discharging of letters may take place with the device in the position 7c. Contacts s, o, m, u may be replaced by optical or mechanical arrangements. A circuit, Fig. 4 (not shown), includes relay means for indicating when the device is halffull.