Adjustable electric magnetic vibrator

Claim 1

AN ELECTROMAGNETIC VIBRATOR COMPRISING: A HOUSING INCLUDING A BASE, A PERIPHERAL SIDEWALL PROJECTING AXIALLY FROM SAID BASE AND A RASIALLY OUTWARDLY EXTENDING FLANGE ON SAID SIDEWALL NEAR THE END THEREOF OPPOSITE THE BASE, SAID HOUSING BEING CONSTRUCTED AND ARRANGED FOR SECUREMENT TO A HOPPER OR THE LIKE FOR INDUCEMENT OF VIBRATIONS THEREIN; A FERROMAGNETIC CORE SECURED IN SAID HOUSING; A WIRE COIL RECEIVED ON SAID CORE FACING OUTWARDLY OF SAID HOUSING BASE AND CONSTRUCTED AND ARRANGED FOR CONNECTION TO A SUPPLY OF PULSATING ELECTRIC CURRENT; A METAL PLATE; AN ARMATURE SECURED TO THE UNDERSIDE OF SAID METAL PLATE IN THE CENTRAL REGION THEREOF, SAID METAL PLATE EXTENDING LATERALLY BEYOND SAID ARMATURE AT LEAST THROUGHOUT A PORTION OF THE PERIMETER THEREOF; RESILIENT MEANS SECURING SAID METAL PLATE, PERIPHERALLY OF SAID ARMATURE, TO SAID HOUSING FLANGE FOR LIMITED OSCILLATION OF THE PLATE AND ARMATURE TOWARD AND AWAY FROM THE COIL AND CORE; SAID RESILIENT MEANS INCLUDING AT LEAST ONE BODY OF RESILIENT MATERIAL RECEIVED BETWEEN SAID METAL PLATE AND SAID FLANGE; MEANS DEFINING AN OPENING AXIALLY THROUGH SAID FLANGE; A LONGITUDINALLY ADVANCEABLE-RETRACTABLE ELEMENT RECEIED THROUGH SAID OPENING AND ENGAGING THE BODY OF RESILIENT MATERIAL BETWEEN THE FLANGE AND METAL PLATE IN A SENSE TO FORCE THE BODY OF RESILIENT MATERIAL AGAINST THE PLATE; ADJUSTMENT MEANS FOR ADVANCING AND RETRACTING SAID ADJUSTMENT ELEMENT FROM EXTEIORLY OF THE HOUSING FOR VARYING THE RESILIENT FORCE WITH WHICH THE BODY OF RESILIENT MATERIAL ENGAGES THE PLATE THEREBY PROVIDING TUNING MEANS FOR THE VIBRATOR EASILY OPERABLE EXTERIORLY OF THE HOUSING THEREOF.