Applicator system for hot melt adhesive and the like

Claim 1

A SYSTEM FOR APPLYING TO A WORK SURFACE THAT IS MOVABLE ALONG A PATH A VISCOUS HOT MELT ADHESIVE IN A CONTROLLED PATTERN OF PARALLEL LINE SEGMENTS, SAID SYSTEM COMPRISING IN COMBINATION STRUCTURE FORMING A HOT MELT TANK OPEN TO ATMOSPHERIC PRESSURE AND ADAPTED TO RECEIVE SOLID ADHESIVE, MEANS FOR CONTROLLABLY HEATING THE TANK STRUCTURE TO MELT ADHESIVE IN THE TANK, STRUCTURE FORMING A PUMP CYLINDER CONTAINING AN AXIALLY RECIPROCABLE PUMP PISTON AND COMMUNICATING WITH THE TANK INTERIOR VIA A CHECK VALVE FOR ADMITING LIQUID ADHESIVE TO THE CYLINDER DURING SUCTION MOVEMENT OF THE PISTON, A PISTON ACTUATOR FOR DRIVING THE PISTON IN INTERMITTENT CYCLES OF MOVEMENT IN TIMED RELATION TO THE WORK SURFACE MOVEMENT, EACH PISTON CYCLE COMPRISING A DELIVERY STROKE FOLLOWED BY A SUCTION STROKE, STRUCTURE FORMING A PLURALITY OF DISPENSING NOZZLES MOUNTABLE ADJACENT THE WORK SURFACE PATH AND COMMUNICATING IN PARALLEL WITH THE PUMP CYLINDER, AN INDIVIDUAL NORMALLY CLOSED VALVE FOR EACH NOZZLE NORMALLY CLOSING THE COMMUNICATION BETWEEN THAT NOZZLE AND THE CYLINDER AND ACTUABLE IN RESPONSE TO ADHESIVE PRESSURE TO PERMIT OUTWARD FLOW OF ADHESIVE FROM THE NOZZLE, AND MEANS FOR ADJUSTABLY LIMITING THE RATE OF FLOW FROM THE TANK INTERIOR TO THE PUMP CYLINDER TO PRODUCE AN ADJUSTABLY VARIABLE SUBATMOSPHERIC PRESSURE IN THE CYLINDER DURING THE SUCTION STROKE OF THE PUMP PISTON AND THEREBY INSURE CLOSURE OF SAID VALVES.