Lubrication system for chain saws

Claim 1

IN A PORTABLE CHAIN SAW OF THE TYPE POWERED BY AN INTERNAL COMBUSTION ENGINE HAVING A PISTON AND CYLINDER ASSEMBLY AND ENGINE CONTROL MEANS AND HAVING AN ENDLESS SAW CHAIN TRAINED ABOUT A GUIDE BAR AND MEANS OPERATIVELY CONNECTING SAID ENGINE TO SAID CHAIN FOR DRIVING THE SAME, A LUBRICATION SYSTEM FOR LUBRICATING THE SAW CHAIN AND GUIDE BAR, COMPRISING (A) A LUBRICANT RESERVOIR, (B) A PRESSURIZING LINE COMMUNICATING BETWEEN SAID RESERVOIR AND THE ENGINE CYLINDER TO PLACE THE LUBRICANT IN THE RESERVOIR UNDER GREATER THAN ATMOSPHERIC PRESSURE WHEN THE ENGINE IS OPERATING, (C) A VALVE AND PUMP ASSEMBLY HAVING A BODY HAVING SEPARATE FIRST AND SECOND CHAMBERS, (D) A VALVE IN SAID FIRST CHAMBER SELECTIVELY CONTROLLING THE FLOW OF LUBRICANT THERETHROUGH, (E) SAID VALVE BEING OPERATIVELY CONNECTED TO AND RESPONSIVE TO POSITIONAL CHANGES OF SAID ENGINE CONTROL MEANS, (F) SAID BODY HAVING A FIRST PASSAGE COMMUNICATING AT ITS UPSTREAM END WITH SAID FIRST CHAMBER DOWNSTREAM OF SAID VALVE AND COMMUNICATING AT ITS DOWNSTREAM END WITH SAID SECOND CHAMBER, (G) SAID BODY HAVING A SECOND PASSAGE COMMUNICATING AT ITS UPSTREAM END WITH SAID FIRST CHAMBER UPSTREAM OF SAID VALVE AND CONNUMICATING AT ITS DOWNSTREAM END WITH SAID SECOND CHAMBER, (H) A CHECK VALVE DISPOSED AT THE DOWNSTREAM END OF SAID SECOND PASSAGE AND NORMALLY BIASED TO CLOSED POSITION, (I) A METERING VALVE IN SAID FIRST CHAMBER DOWNSTREAM OF SAID FIRST MENTIONED VALVE TO CONTROL THE FLOW OF LUBRICANT THROUGH SAID FIRST PASSAGE, (J) SAID BODY HAVING AN INLET PORT COMMUNICATING WITH SAID FIRST CHAMBER AND HAVING AN OUTLET PORT COMMUNICATING WITH SAID SECOND CHAMBER, (K) A CONDUIT BETWEEN SAID LUBRICANT CHAMBER AND SAID INLET PORT, (L) A LUBRICANT FEED LINE BETWEEN SAID OUTLET PORT AND SAID GUIDE BAR, AND (M) A PISTON RECIPROCABLE WITHIN A CYLINDER COMMUNICATING WITH SAID SECOND PASSAGE UPSTREAM OF SAID CHECK VALVE, (N) SAID PISTON BEING SELECTIVELY OPERABLE UPON EACH WORKING STROKE TO FORCE LUBRICANT THROUGH SAID CHECK VALVE AND THROUGH SAID LUBRICANT FEED LINE TO CLEAR THE SAME OF ANY BLOCKING OBSTRUCTION.