Automatic combination weighing machine

Claim 1

An automatic combination weighing machine, comprising a plurality of retaining hoppers arranged in a circle, each of said hoppers having a normally closed gate at the bottom, which is opened temporarily in response to a gating signal, a shoot rotatably supported about the central axis of said circle, whereby the outlet of said shoot can face the inlet of any of said hoppers, means for intermittently rotating said shoot to cause said outlet to face sequentially the inlets of said hoppers, a single weighing device for weighing an article to be weighed and producing a weight output indicative of the weight of said article, means for feeding a plurality of articles to be weighed sequentially one by one or group by group and then discharging them into said shoot in synchronism with the rotation of said shoot, a plurality of memories corresponding respectively to said hoppers, means for supplying said weight signal sequentially to said memories in synchronism with the rotation of said shoot, arithmetic means for summing up combination inputs of said memories and producing an output when the sum has a value within a predetermined range, a plurality of normally open switches for coupling the outputs of said memories respectively to the inputs of said arithmetic means, switch control means coupled to the control inputs of said switches for selectively closing said switches in accordance with predetermined combinations, and a temporary memory for successively storing the output of said switch control means and applying the content at that time to the reset inputs of said respective memories as reset signals and, at the same time, to the gates of said respective hoppers as said gating signals in response to the output of said arithmetic means, thereby clearing said memories corresponding to said closed switches and, at the same time, opening the gates of said hoppers corresponding to said memories.