Patent GB-537243-A (GB)
Title: Improvements in or relating to optical devices for reading perforated records
IPC: B41J2/44
Filed: 1939-12-12
Abstract: 537,243. Statistical-apparatus. BRITISH TABULATING MACHINE CO., Ltd. (International Business Machines Corporation). Dec. 12, 1939, No. 32080. [A Specification was laid open to inspection under Sect. 91 of the Acts, June 14, 1940.] [Class 106 (i)] [Also in Group XX] Apparatus for reading perforated statistical records comprises means (plate 503) for supporting characters (0, 1, 2 ... 9) in spaced relationship corresponding to the perforation index point positions on the record cards C a light source 500 to illuminate the characters, an optical system (lens bars 504) for projecting an image of each character in a column to a common image position (on ground glass screen 505) and images of characters in different columns to different-common image positions all in alignment in one plane, and means to register the index positions on the record card with the character positions so that images registering with record perforations are projected in a single line on screen 505. The card feed of the tabulator embodying the present device is modified so that between the upper and lower reading brushes UB, LB the card is brought to rest in the position C1 between plate 503 and lenses 504, at a card group change for groupedcard working or at each cycle where manual starting is necessary to feed the cards one by one through the machine. This brings the card into exact registration with the opaque characters 0, 1 ... 9 marked on the transparent plate 503. There is a lens bar 504 for each row of index positions, as shown in Fig. 3, and these lenses are so shaped that the refracted rays all fall on a common line on the translucent screen 505 with all the rays from any one column falling on a common spot on that line. Since, however, there is only one hole in a card column, only one image in each column of characters on the plate 503 will pass through the card and be projected on to plate 505 ; and although the card holes are in different positions in their columns they will be projected in single line on screens 505, as shown in Fig. 6. For verifying, the lamp switch 501 is closed and the reading of each card, fed individually, is seen on screen 505 and compared with original data. For grouped-card working, switch 501 is opened. 338 is one of the usual relays which at card group change becomes de-energized to stop card-feeding &c. In the present instance it also closes contacts 338c so that lamp 500 illuminates the plate 503 in conjunction with the halted card. The operator reads the screen 505 and selects the correct ledger sheet for the new group. Screen 505 is held in an opaque partition 506 and there are two laterally sliding shutters to the screen, Fig. 4 (not shown), whereby only the readings of desired card columns are read off the screen. Preferably, a camera 512 is used, its hood 550 being placed over the casing 507 so that a gear wheel in the camera meshes with a wheel driven from the tabulator, the former wheel driving mechanism to actuate the camera shutter and the film feed. In this way the film is exposed each time a card is halted at plate 503 and the data of successive cards are recorded, each in a single line, on the film as shown in Fig. 6. By using fast photographic film, the records may be made without balting each card at plate 503.