Spreader for fertilizer and the like

Claim 1

A MOBILE SPREADING UNIT COMPRISING A RECEPTACLE FOR GRANULAR, PULVERULENT MATERIAL, AT LEAST ONE WHEEL SUPPORTING THE RECEPTACLE, MEANS DEFINING A DISCHARGE OUTLET IN SAID RECEPTACLE INCLUDING A VALVE ELEMENT FOR SELECTIVELY VARYING FLOW OF MATERIAL THROUGH SAID DISCHARGE OUTLET, SAID VALVE ELEMENT ACTUATABLE BETWEEN A FIRST LIMIT POSITION AFFORDING FLOW OF MATERIAL THROUGH SAID DISCHARGE OUTLET AND A SECOND LIMIT POSITION CLOSING SAID DISCHARGE OUTLET, A SPREADER ELEMENT UNDERLYING SAID DISCHARGE OUTLET OPERABLE TO DISPERSE SAID GRANULAR MATERIAL, ACTUATION OF SAID VALVE ELEMENT BETWEEN SAID LIMIT POSITIONS OPERABLE TO VARY THE SIZE OF SAID DISCHARGE OUTLET AND MAINTAIN THE CENTER OF SAID DISCHARGE OUTLET IN A SUBSTANTIALLY FIXED POSITION RELATIVE TO SAID SPREADER ELEMENT THEREBY TO PROVIDE A UNIFORM SPREADING PATTERN THROUGHOUT THE RANGE OF ADJUSTMENT OF THE SIZE OF SAID DISCHARGE OUTLET, MEANS MOUNTING SAID SPREADER ELEMENT FOR ROTATION IN AN OPERATIVE POSITION TO BE DRIVEN CONCURRENTLY WITH THE WHEEL UPON ADVANCE OF SAID UNIT TO DISPERSE SAID MATERIAL AND A NON-ROTATABLE INOPERATIVE POSITION INDEPENDENT OF THE WHEEL AND A COMMON OPERATOR FOR SAID VALVE AND SPREADER ELEMENTS FOR POSITIONING SAID SPREADER ELEMENT IN SAID OPERATIVE POSITION WHEN SAID VALVE ELEMENT IS IN SAID FIRST POSITION FOR SELECTIVELY ACTUATING SAID VALVE ELEMENT TO PROVIDE A DISCHARGE OUTLET OF PREDETERMINED SIZE AND FOR POSITIONING SAID SPREADER ELEMENT IN SAID INOPERATIVE POSITION WHEN SAID VALVE ELEMENT IS IN SAID SECOND POSITION.