An apparatus for detecting an incorrect position of the movable ends document do 872,615 filed june 10 (see fig. 5).

摘要

818,986. Photo-electric control of conveyers. INTERNATIONAL COMPUTERS & TABULATORS Ltd., [formerly BRITISH TABULATING MACHINE CO. Ltd.]. Oct. 11, 1955, No. 28914/55. Class 40 (3). The regular positioning of sheets 10 moving along a conveyer 9 is checked photo-electrically and alarm and/or control action initiated when incorrect positioning occurs. In one embodiment the upper surface of the conveyer 9 is highly polished and a mirror 7 is placed parallel to, and above, a length thereof. Light beams from sources 5a, 5b and 5c are reflected back and forth and strike the conveyer 9 at points spaced by the correct spacing of the sheets before reaching photo-cell 8 via mirrors 6a, 6b and 6c. Thus when the sheets 10 are correctly spaced there are regularly spaced intervals when the light beams are all reflected from the surface 9 and the light directed on the cell 8 is of maximum intensity. A cam synchronized with the conveyer drive is arranged to feed the potential developed by the current through the cell at such times to a comparison device similar to that described below and an erroroperated device. If one or more of the sheets are displaced the peak light intensity reaching the cell is diminished and the error device operated. In a modification, light sources 5d, 5e, 5f and 5g spaced apart a multiple of the sheet spacing direct beams of light downwards through apertures 17d, 17e, 17f, and 17g to photo-cells 18d, 18e, 18f and 18g. With correct spacing of the sheets and cam switch 23 closed in synchronism with the presentation of a clear light path from each source to its respective cell the potential applied to condenser 22 from the switch is almost the same as that continuously applied through resistor 20 from constantly illuminated balancing photo-cell 18x. There is thus no output over line 25 to actuate the error device. If, however, one or more of the sheets are displaced then, when the cam switch closes, at least one of the photo-cells will be obscured and a positive pulse will be fed out over line 25 to operate the the error device. Specification 751,931, [Group XIX], is referred to.