GB749092A - Improvements in or relating to measuring instruments and balances - Google Patents

Abstract

749,092. Photo-electric weighing apparatus. SCHENCK MASCHINENFABRIK DARMSTADT GES., C. Oct. 5, 1953 [Nov. 29, 1952], No. 27319/53. Class 40 (3). [Also in Groups XVIII and XIX] The deflection of the pendulum of a measuring instrument, e.g. a weighing machine, is transmitted electrically in the form of a proportionate number of pulses which are fed to electronic counting apparatus associated with a printing mechanism. As shown, the pendulum 3 (Fig. 1) of a weighing machine, carrying a visual scale 10, carries a magnetic tape 11 which has a number of equispaced marks superposed thereon. When the pointer 3 reaches its rest position a motor 14 is started by manual or automatic operation of a switch 15 to drive an arm 7 carrying sound heads 8 and 9 to follow the tape 11, whereupon a series of pulses is transmitted by the head 8 to known electronic counting circuits 17 to set a weight-printing mechanism 20. At the zero position on tape 11 a switching-off pulse is received via head 9 which stops the motor 14, and the counting circuits 17, and returns arm 7 to its starting position. To obtain a larger number of pulses for greater accuracy the tape 11 and associated head 8 may be duplicated. In a photo-electric embodiment the tape is replaced by a band 36 (Fig. 3) with a series of marks which produce corresponding pulses in a photo-cell 38 as the pendulum 37 is deflected, an automatic switch 39 directing the pulses to plus or minus counting mechanisms 40, 41 in accordance with the direction of movement of the pendulum, the weight-printing mechanism Z indicating the algebraic sum of the counters. The deflection is also indicated directly by projecting an image of a scale 31 on a screen 34 by a lens 32 and mirror 33.