Patent ID: 6622688
Filing Date: 2003-09-23
Classification: F01M,F02B

Abstract:
A hand-held, portable, power tool adapted to be carried by an operator while in use, comprising:a frame, including a handle engageable by an operator; an implement cooperating with the frame and having a rotary-driven input member; a lightweight, four-stroke cycle, internal combustion, spark-ignition engine attached to said frame wherein said engine comprising: a lightweight aluminum engine block defining a cylinder head assembly, a cam housing, a crank chamber and a cylindrical bore; an intake valve and exhaust valve in said cylinder head assembly; a piston slidably disposed in said cylindrical bore; a crankshaft supported by at least one bearing in said crank chamber, said crankshaft being drivably connected to said piston, and having an output end cooperating with an input end of said implement; a cam rotatably mounted in said cam chamber and driven by said crankshaft at less than the full speed of said crankshaft; and a valve cover on said cylinder head defining a valve chamber.