Abstract: A four-stroke engine employs engine vibration for lubricating engine components. The engine vibration induces a ripple in a surface portion of the oil in an oil reservoir, which is located within a crankcase of the engine. The oil ripple causes misting of the oil, which lubricates exposed engine components. Providing a crankcase wall thickness of about 1.5 mm or less can increase the engine vibration. Alternatively, a clearance area located within the crankcase can be decreased to facilitate contact of the oil surface ripple with a counterweight, thereby splashing the oil onto exposed engine components. Vibration of the engine can be further increased by coupling a vibration plate or spring to a portion of the crankcase.

Abstract: A four-stroke engine includes a piston cylinder, and a piston located in the cylinder and movable within the cylinder. The engine includes a crankcase attached to the cylinder, the piston providing a separation boundary of a combustion portion of the cylinder from the crank case, and a crank member located within the crankcase and operatively connected to the piston. The engine including components for operating the engine in a four-stroke sequence, and components for introducing a fuel mixture into the combustion portion of the cylinder, the fuel mixture having an ability to lubricate. The engine including a construction and/or configuration for promoting passage of a portion of the mixture from the combustion portion of the cylinder to the crankcase in a sufficient amount to provide lubrication within the crankcase without reservoir lubricant in the crankcase.

Abstract: A power tool includes vibration isolation material positioned between an engine shroud and a drive shaft housing. The vibration isolation material isolates the drive shaft housing from engine vibration for radial, axial, and torsional movement without utilizing intermediate components.

Abstract: A power tool includes vibration isolation material positioned between an engine shroud and a drive shaft housing. The vibration isolation material isolates the drive shaft housing from engine vibration for radial, axial, and torsional movement without utilizing intermediate components.

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 four-stroke engine employs engine vibration for lubricating engine components. The engine vibration induces a ripple in a surface portion of the oil in an oil reservoir, which is located within a crankcase of the engine. The oil ripple causes misting of the oil, which lubricates exposed engine components. Providing a crankcase wall thickness of about 1.5 mm or less can increase the engine vibration. Alternatively, a clearance area located within the crankcase can be decreased to facilitate contact of the oil surface ripple with a counterweight, thereby splashing the oil onto exposed engine components. Vibration of the engine can be further increased by coupling a vibration plate or spring to a portion of the crankcase.

Abstract: A power tool having a rotary implement driven by a four-cycle engine. The engine crankcase is through a passageway which extends through a camshaft to a valve chamber. The rotating shaft member inhibits the escape of lubricating oil when the engine is running while permitting a lubricating oil mist to circulate through the engine.

Abstract: A four-stroke engine includes a piston cylinder, and a piston located in the cylinder and movable within the cylinder. The engine includes a crankcase attached to the cylinder, the piston providing a separation boundary of a combustion portion of the cylinder from the crank case, and a crank member located within the crankcase and operatively connected to the piston. The engine including components for operating the engine in a four-stroke sequence, and components for introducing a fuel mixture into the combustion portion of the cylinder, the fuel mixture having an ability to lubricate. The engine including a construction and/or configuration for promoting passage of a portion of the mixture from the combustion portion of the cylinder to the crankcase in a sufficient amount to provide lubrication within the crankcase without reservoir lubricant in the crankcase.

Abstract: A power tool having a rotary implement driven by a four-cycle engine. The engine crankcase is through a passageway which extends through a camshaft to a valve chamber. The rotating shaft member inhibits the escape of lubricating oil when the engine is running while permitting a lubricating oil mist to circulate through the engine.

Abstract: 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. The crankshaft ventilation passage establishes lean crankcase gas distribution to the engine air/fuel intake. The crankcase is designed to avoid flow of liquid oil through the crankshaft passage when the engine is not running.

Abstract: A power tool having a rotary implement driven by a four-cycle engine. The engine crankcase is through a passageway which extends through a camshaft to a valve chamber. The rotating shaft member inhibits the escape of lubricating oil when the engine is running while permitting a lubricating oil mist to circulate through the engine.

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: 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. The crankshaft ventilation passage establishes lean crankcase gas distribution to the engine air/fuel intake. The crankcase is designed to avoid flow of liquid oil through the crankshaft passage when the engine is not running.

Abstract: A power tool having a rotary implement driven by a four-cycle engine. The engine crankcase is through a passageway which extends through a camshaft to a valve chamber. The rotating shaft member inhibits the escape of lubricating oil when the engine is running while permitting a lubricating oil mist to circulate through the engine.

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 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 power tool having a rotary implement driven by a four-cycle engine. The engine crankcase is through a passageway which extends through a camshaft to a valve chamber. The rotating shaft member inhibits the escape of lubricating oil when the engine is running while permitting a lubricating oil mist to circulate through the engine.

Abstract: A power tool having a rotary implement driven by a four-cycle engine. The engine crankcase is vented via an axial passageway which extends through at least one cam shaft axial shaft of the crankshaft and cam shaft. The rotating shaft member inhibits the escape of oil when the engine is running due to centrifugal force.

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: An internal combustion engine is provided with a cartridge containing a fuel/oil mixture where the fuel is liquid, normally gaseous fuel. The cartridges can be readily mounted or demounted from the engine, and provide flexibility of use coupled with easy starting. The use of the fuel/oil cartridges eliminates the need to separately mix oil and fuel, and eliminates substantial contact of the user with an oily fuel/oil mixture. The two cycle and four cycle cartridge-type engines are suitable for use in many hand-powered implements, including line trimmers, chain saws, leaf blowers, hedge trimmers, etc.