GB672967A - Improvements in or relating to apparatus for photographic time recording - Google Patents

Abstract

672,967. Photographic time recording. BECKMAN, J. C., and WHITLEY, E. M. July 27, 1948 [Aug. 11, 1947], No. 20014/48. Class 98 (i). [Also in Group XIX] Apparatus for photographically recording accumulated time on a continuously moving film in a camera wherein the film is continuously exposed through a narrow vertical slit, comprises a motor driving a counting device to effect the display thereon of numerals corresponding to successive time intervals, means for projecting images of the numerals on to said moving film, and means for-illunlinating the numerals for very short lengths of time at a frequency greater than 100 times per second to prevent distortion of the successive numeral images on the film. As shown, a counter 14 of known type is driven by a constant-speed motor 15 through a shaft 19 with a ten-lobed cam 18 which closes contacts 17 which connect a lamp 16 in parallel with a condenser 20, thereby causing each successive number to be illuminated by a brief flash of light as it appears. The apparatus is mounted in the casing of a camera in which the film 11 moves continuously past a slit 12 in a mask 10, such as a camera for timing races. Light from the numbers, when illuminated by a flash, is reflected by mirrors 22, 26 on to the film 11, whereon an image is formed by a lens system 24, 25. To allow for the time taken for the motor to run up to speed, the numbers may be projected through an opening 27 before the slit 12. Alternatively the opening 27 is abreast of, or a continuation of, slit 12, and the counter starts from a given number, set permanently or by a hand wheel 36 on shaft 19. The motor may be started by a switch 32 operated by electrical means for starting the race. When the contestants approach the finishing line, the film is started and a switch 34 in the lamp circuit is closed. The images of the contestants are recorded on the film in the usual manner together with the numbers which indicate the time in <SP>1</SP>/ 100 sec. intervals for each contestant to complete the course. After recording the finish, motor 15 and the film are stopped, and counter 15 returned to zero, or the number at which it started, in known manner by a lever 35. Specification 537,253 is referred to.