Abstract: An exhaust silener for a compact 2-stroke cycle internal combustion engine has a housing, a sheet of sound absorbing material provided on the inner surface of the housing, and an oxidation catalyst means provided on the surface of the sound absorbing material. The catalyst serves to promote oxidation of unburnt components of lubricating oil in exhaust gases.

Abstract: A mowing apparatus has an elongated handling rod on the distal end of which is mounted a gear unit having a casing and an output shaft which extends substantially perpendicularly to the handling rod. The apparatus further includes a first disk cutting blade mounted so as to cover the side of the casing adjacent the output shaft, and a second disk cutting blade superposed on the side of the first disk cutting blade adjacent the casing. A connecting pin interconnects the first and second disk cutting blades such that the disk cutting blades are rotatable relative to each other about their axes. An eccentric shaft is adapted to revolve about the axis of the output shaft in accordance with the rotation of the output shaft, and is received in a cam slot provided for rotation as a unit with the second disk cutting blade about the connecting pin, so that the can slot reciprocate circumferentially about the connecting pin in accordance with the revolution of the eccentric shaft.

Abstract: A spark arrester is mounted in a tail pipe of an exhaust pipe of an engine, in particular a 2-strokecycle engine, and prevents sparks from being emitted. The spark arrester includes a sack-like member of a wire mesh and a cylindrical member secured to open end of the sack-like member. The cylindrical member received in the tail pipe is retained therein by a resilient retainer in a groove formed in the inner peripheral wall of the tail pipe.

Abstract: A portable engine unit is provided. The unit comprises an engine including a clutch, a crankcase enclosing a crank shaft, an engine cylinder enclosing a piston and a piston rod, a carburetor, an air filter, a recoil starter, and a muffler; and a housing for enclosing the engine, comprising at least two portions which are assembled and disassembled along a plane including the axis of rotation of an output shaft of the engine to enclose and expose the engine.

Abstract: A dust collector having a selector valve which enables a cleaning pipe to be connected with either a suction circuit communicating with a dust collecting portion, or a discharge circuit communicating with the discharge opening of a fan. By carrying out the shifting operation of said selector valve, the dust collector can be changed to suck and collect dust, or to blow and gather dust without rearranging the cleaning pipe.

Abstract: A portable engine unit is provided. The unit comprises an engine including a clutch, a crankcase enclosing a crank shaft, an engine cylinder enclosing a piston and a piston rod, a carburetor, an air filter, a recoil starter, and a muffler; and a housing for enclosing the engine, comprising at least two portions which are assembled and disassembled along a plane including the axis of rotation of an output shaft of the engine to enclose and expose the engine.