GB565729A - Improvements in automatic weighing machines - Google Patents

Abstract

565,729. Automatic-feed weighers. SIMON, W. G., and SIMON, F. R. March 8, 1943, No. 3698. [Class 143] In an automatic weighing- machine the material is fed to the weigh pan by a tray which is reciprocated at a rate in the region of 2,000 to 3,000 complete reciprocations per minute and with an amplitude in the order of 1/32nd of an inch, the object being to ensure that irrespective of the physical nature of the material the amount in suspension when the feed is cut off is substantially constant or varies only within small limits. The material passes through an inlet 1 on to a feed tray 2 reciprocated by an electro-mechanical vibrator 4. The front of the tray is supported by a spring 7 and extends into a housing 18 surmounting an enclosure 17 for the upper part of the weigh pan 8. Flexible dust-proof seals 19 are provided between the tray and housing 18 and feed inlet 1. The knife-edges of the scale beam 9 are situated outside the housings to avoid the deleterious effect of dust. The discharge gate 23 of the weigh pan is connected by a link 26 to a quadrant 27 and is locked in the closed position by a catch 30, 31, Fig. 4, engaging a notch 29 in the quadrant. The material entering the weigh pan causes it to descend followed by a weighted lever 34, Fig. 3, which ultimately 'descends upon a roller 35 at the end of an arm 39 projecting from a shaft 40. When the requisite weight is made up, a peg 37 on the lever 34 rides down the roller 35 and rocks the shaft 40 together with arms 41, 42. The arm 41 breaks the circuit of the vibrator 4 and stops the feed. A peg 43 on the weigh pan co-operates with the arm 42 to ensure movement of the contact arm 41. The end of the descending lever 34 now strikes the catch 30, 31, Fig. 4, and .disengages it from the quadrant 27, allowing the discharge gate 23 to open and discharge the weighed material. The quadrant on liberation, slides a bolt 47 into the path of the arm 42 and delays the return of the contact arm 41 until the quadrant and discharge gate have returned, thus preventing premature restarting of the feed.