GB1471320A - Weight indicating apparatus - Google Patents

Abstract

1471320 Weighing electrically TANITA CORP 18 June 1974 [18 June 1973 5 Sept 1973] 27046/74 Heading G1N A digital display weighing apparatus includes a pointer 1 angularly displaceable proportional to applied weight and having a depending member 11 at one end thereof arranged to pass between a permanent magnet MG and a reed switch LDSW so as to de-energize a relay R Y. Rotation of the pointer by an applied weight allows the energization of the relay RY to close contacts t 3 -t 5 so motor M is energized to rotate a worm W and worm-wheel 3 to follow the pointer until the member 11 is at a position where it again screens the reed switch from the magnet MG so the contact ct 2 short-circuit the motor and it stops. To provide a number of electrical pulses corresponding to the rotation of the motor and thus to the angular displacement of the pointer, the motor shaft carries a permanent magnet MG 1 which acts with a further reed switch LDSW 1 to provide a pulse for each incremental rotation of the pointer corresponding to 0À25 kg weight. These pulses are gated through NOR 1 to counter CC linked with digital display unit DSP. The holding circuit HDC acts to maintain the weight display at DSP even when the pointer has returned to its initial position following removal of the weight until another weight is applied. Preset circuit RSC then acts through NOt circuit NOt 1 to reset the counter CC whereupon the display unit reads zero. Sensing of the member 11 may be photo-electric, Fig. 3 (not shown) or by a Hall plate Fig. 4 (not shown) or by a variable/magnetic reluctance device Fig. 5 (not shown). Motor rotations may be sensed by an apertured disc and photoelectric transducer Fig. 6 (not shown) or by a Hall effect switch Fig. 7 (not shown).