Fast vertical stroke moving coil transducer

Claim 1

APPARATUS FOR PERIODICALLY PRODUCING A FAST VERTICAL STROKE COMPRISING: (A) A DRIVE ARMATURE HAVING A CONDUCTING WIRE WOUND INTO A NUMBER OF RECTANGULAR LOOPS CEMENTED TOGETHER TO FORM A RIGID STRUCTURE; (B) FIRST AND SECOND RODS SUPPORTING SAID DRIVE ARMATURE ON EITHER SIDE THEREOF, EACH ROD HAVING BALL STOPS AFFIXED THERETO ABOVE AND BELOW SAID DRIVE ARMATURE; (C) MEANS ADAPTED TO RECEIVE SAID RODS FOR CONFINING THE MOTION OF SAID RODS AND DRIVE ARMATURE TO A VERTICAL PLANE AND FOR ENGAGING SAID BALL STOPS TO DEFINE THE VERTICAL STROKE OF SAID DRIVE ARMATURE; (D) A NORTH AND A SOUTH MAGNETIC POLE FACE LOCATED OPPOSITE ONE ANOTHER AND ADAPTED TO PERMIT THE UPPER AND LOWER HORIZONTAL LEGS OF SAID DRIVE ARMATURE TO MOVE THEREBETWEEN; (E) A SPIRAL SPRING RESILIENTLY HOLDING SAID DRIVE ARMATURE AT THE TOP OF ITS STROKE WHEREBY SAID UPPER BALL STOPS ARE SEATED AGAINST SAID BALL-STOP ENGAGING MEANS SUCH THAT ONLY THE LOWER HORIZONTAL LEG OF SAID DRIVE ARMATURE IS BETWEEN SAID MAGNETIC POLE FACES; (F) A SOFT IRON ARMATURE; (G) MEANS FOR RESILIENTLY ATTACHING SAID SOFT IRON ARMATURE TO SAID FIRST AND SECOND SUPPORTING RODS WHEREBY SAID SOFT IRON ARMATURE MOVES THEREWITH; (H) A FIXED ELECTROMAGNET LOCATED TO CAUSE A SMALL AIR GAP TO EXIST BETWEEN SAID ELECTROMAGNET AND A SURFACE OF SAID SOFT IRON ARMATURE WHEN SAID DRIVE ARMATURE IS AT THE BOTTOM OF ITS STROKE; (I) MEANS FOR PERIODICALLY SUPPLYING PULSED ENERGIZING CURRENT TO SAID DRIVE ARMATURE CONDUCTING WIRE; SAID ENERGIZING CURRENT FLOWING IN THE LOWER HORIZONTAL LEG OF SAID DRIVE ARMATURE TO FORCE IT DOWNWARD THEREBY CAUSING THE UPPER PORTION OF SAID DRIVE ARMATURE CONDUCTOR TO MOVE BETWEEN SAID POLE FACES AND THE LOWER HORIZONTAL LEG OF SAID DRIVE ARMATURE TO MOVE BELOW SAID POLE FACES, SAID ENERGIZING CURRENT ENDING BEFORE SAID DRIVE ARMATURE REACHES THE BOTTOM OF ITS STROKE; (J) CURRENT SUPPLY MEANS FOR ENERGIZING SAID ELECTROMAGNET, SAID ELECTROMAGNET BEING ENERGIZED BEFORE SAID DRIVE ARMATURE REACHES THE BOTTOM OF ITS STROKE WHEREBY SAID DRIVE ARMATURE IS HELD AT THE BOTTOM OF ITS STROKE BY ACTION OF SAID ELECTROMAGNET ENGAGING AND HOLDING SAID SOFT IRON ARMATURE THEREBY CLOSING SAID AIR GAP AGAINST THE RESILIENT FORCE HOLDING SAID SOFT IRON ARMATURE, AND FOR DE-ENERGIZING SAID ELECTROMAGNET AFTER A PREDETERMINED TIME, WHEREBY SAID DRIVE ARMATURE IS FORCED TO THE TOP OF ITS STROKE BY SAID SPIRAL SPRING; AND (K) MEANS FOR SUPPLYING A SECOND CURRENT PULSE TO SAID DRIVE ARMATURE CONDUCTING WIRE RESPONSIVE TO THE TRAILING EDGE OF THE PULSE OF SAID ELECTROMAGNET CURRENT SUPPLY MEANS TO DECELERATE SAID DRIVE ARMATURE BEFORE REACHING THE TOP OF ITS STROKE.