Abstract: A portable, operator-carried power tool having an implement supported on frame, and a lightweight, four-stroke, engine drivably connected to the implement. The engine has a crankshaft situated in a crankshaft housing and a cylinder block secured to the housing, the crankshaft being provided with a crankcase ventilation passage extending between the crankcase and an outlet end in communication with an air/fuel induction passage. A passage establishes communication between the interior of the crankcase and the valve chamber through a cam and cam gear region of the cylinder block. An oil mist generator is connected drivably to the crankshaft for agitating liquid oil in the crankcase to establish a lubricating oil mist. The crankcase, cam region and valve chamber form a containment whereby oil mist is distributed throughout the engine during operation regardless of angular orientation.

Abstract: A portable, operator-carried power tool having an implement supported on an operator-carried frame, and a lightweight, four-stroke, internal combustion engine drivably connected to the implement and supported by the frame. The engine has a crankshaft situated in a crankshaft housing and a cylinder block secured to the crankshaft housing, the crankshaft being provided with a crankcase ventilation passage extending between the crankcase and an outlet end in communication with an air/fuel induction passage. A passage establishes communication between the interior of the crankcase and the valve chamber through a cam and cam gear region of the cylinder block. An oil mist generator is connected drivably to the crankshaft for agitating liquid oil in the crankcase to establish a lubricating oil mist. The crankcase, the cam region and the valve chamber form a closed oil mist containment whereby lubricating oil mist is distributed throughout the engine during operation regardless of angular orientation of the engine.

Abstract: A compression release mechanism for a combustion chamber in an internal combustion engine comprises a pressure relief valve assembly and a control member. The valve assembly includes a valve body and a plunger cooperating with a vent passageway through the valve body to selectively allow pressure relief through the vent passageway. The control member cooperates with the plunger and is movable between an engaged position in which the control member urges the plunger toward the open position, and a disengaged position in which the plunger is held in the closed position. When the control member is engaged, the plunger oscillates between the open and closed positions in response to combustion chamber pressures during a combustion cycle which facilitates engine start-up while the compression release mechanism is engaged.

Abstract: A line trimmer head is provided including a rotatable drive shaft and a housing mounted to the drive shaft for rotation therewith. The housing has an open end and at least one peripheral aperture formed through the housing. A spool subassembly is positioned at least partially within the housing adjacent the open end of the housing. The subassembly includes a spool having at least one flange extending radially outwardly from the periphery thereof, a cog ring secured to the spool, and a ratchet and pawl assembly formed between the cog ring and spool. The ratchet and pawl assembly allows rotation of the spool in a first direction with respect to the cog ring for winding line around the spool while preventing spool rotation in a second direction opposite the first direction to facilitate line feed bumping and line trimming operations. In an alternative embodiment, the pawl is integrally molded with the spool to eliminate the separate spring-pawl assembly.

Abstract: A split-boom power tool includes a housing adapted to carry a battery or motor. A first boom member connected to the housing includes an electromechanical or mechanical joint (i.e., coupling) connected thereto for receiving a second boom member, which carries an attachment. The attachment may include a hedge trimmer, line trimmer, pruner, blower, or extension. Various couplings or mechanical joints are provided.

Abstract: A line trimmer head is provided including a rotatable drive shaft and a housing mounted to the drive shaft for rotation therewith. The housing has an open end and at least one peripheral aperture formed through the housing. A spool subassembly is positioned at least partially within the housing adjacent the open end of the housing. The subassembly includes a spool having at least one flange extending radially outwardly from the periphery thereof, a cog ring secured to the spool, and a ratchet and pawl assembly formed between the cog ring and spool. The ratchet and pawl assembly allows rotation of the spool in a first direction with respect to the cog ring for winding line around the spool while preventing spool rotation in a second direction opposite the first direction to facilitate line feed bumping and line trimming operations.