Electromagnetic control means for a weighing machine

Claim 1

FOR USE IN WEIGHTING MACHINE PROVIDED WITH A MOVABLE WEIGHTING ELEMENT HAVING MEANS FOR SUPPORTING THE LOAD TO BE WEIGHED AND ADAPTED TO BE DEFLECTED IN A AMOUNT PROPORTIONAL TO THE LOAD, MEANS FOR FEEDING A BULK STREAM OF THE MATERIAL TO BE WEIGHED ONTO THE LOAD RECEIVING MEMBER OF THE WEIGHTING ELEMENT, MEANS FOR FEEDING A DRIP STREAM ONTO THE LOAD RECEIVING MEMBER OF THE WEIGHING ELEMENT, THE IMPROVEMENT COMPRISING ELECTRICAL CONTROL MEANS FOR MEASURING MINUTE DEFLECTIONS OF THE WEIGHTING ELEMENT AND FOR CONTROLLING THE OPERATION OF THE BULK AND DRIP STREAM FEEDING MEANS, SAID CONTROL MEANS INCLUDING A POSITION SENSITIVE TRANSDUCER HAVING AN INPUT CIRCUIT AND AN OUTPUT CIRCUIT AND PROVIDED WITH AN ARMATURE OPERATIVELY CONNECTED TO AND MOVABLE WITH SAID WEIGHING ELEMENT, SAID ARMATURE BEING SLIDABLY MOUNTED AND HAVING A TONGUE AND GROOVE CONNECTION WITH SAID WEIGHING ELEMENT WHEREBY THE RELATIVE MOVEMENT BETWEEN SAID ARMATURE AND WEIGHING ELEMENT IN RESPONSE TO THE LOAD BEING WEIGHED IS LINEAR, SAID CONTROL MEANS HAVING PROVISION WHEREBY MINUTE MOVEMENT OF SAID ARMATURE OPERATES TO VARY THE VOLTAGE IN THE OUTPUT CIRCUIT OF THE TRANSDUCER IN AN AMOUNT SUBSTANTIALLY PROPORTIONAL TO THE DEFLECTION MOVEMENT OF THE WEIGHING ELEMENTS, MEANS FOR AMPLIFYING THE VOLTAGE VARIATIONS IN SAID OUTPUT CIRCUIT AND ELECTRORESPONSIVE MEANS CONNECTED IN SAID OUTPUT CIRCUIT AND ACTUATED BY SAID VOLTAGE VARIATIONS, AND MEANS COOPERATING WITH SAID ELECTRORESPONSIVE MEANS AND OPERATIVELY CONNECTED WITH THE BULK AND DRIP FEEDING MEANS FOR TERMINATING THEIR FEEDING OPERATIONS WHEN THE VOLTAGE REACHES DIFFERENT AMOUNTS, SAID WEIGHING ELEMENT COMPRISING A PLURALITY OF UPPER AND LOWER VERTICALLY SPACED AND PARALLEL STIFF LEAF SPRINGS, EACH SECURED AT ITS INNER END AND TO A STATIONARY SUPPORT, A TIE MEMBER CONNECTING THE OUTER ENDS OF SAID LEAF SPRINGS, AN ELONGATED COIL SPRING COOPERATING WITH THE LEAF SPRINGS TO YIELDINGLY SUPPORT A PORTION OF THE WEIGHT OF THE LOAD, AND MEANS CONNECTED WITH SAID LEAF SPRINGS FOR DAMPING THE VIBRATIONS THEREOF, SAID RELATIVELY STIFF LEAF SPRINGS BEING SELECTED SO AS TO HAVE A DEFLECTION VALUE LYING BETWEEN .00002" AND .005" PER 1% OF THE LOAD TO BE WEIGHED, AND SAID POSITION SENSITIVE TRANSDUCER BEING RESPONSIVE TO A DEFLECTION MOVEMENT OF THE ARMATURE AS LOW AS .0001" OR LESS, SAID TRANSDUCER BEING STATIONARILY MOUNTED INTERMEDIATE SAID UPPER AND LOWER LEAF SPRINGS AND HAVING A VERTICAL PORTION PARALLEL TO AND SPACED FROM SAID TIE MEMBERS, SAID TONGUE AND GROOVE CONNECTION INCLUDING A TONGUE EXTENDED FROM SAID ARMATURE COOPERATING WITH A GROOVE FORMED IN AN EXTENSION SROM SAID TIE MEMBER.