Abstract: A waste combustion system includes a porous apparatus for supplying and spraying a suitable amount of water from at least the bottom floor surface and/or a lower inner surface of the furnace. Water vapor generated from the water is dispersed, and it undergoes the water gas reactions with red-hot carbon during a combustion process. The water gas reactions serve as the endothermic reactions which control the temperature within the furnace into suitable temperatures. In addition, while secondary air from a secondary air introducing apparatus is being supplied into the combustion chamber of the furnace, the burning zone of the waste is subjected to violent agitation and stirring actions so as to limit the generation of such substances as nitrogen oxides and soot, hence, to reduce the proportion of pollutants contained in the exhaust gases.

Abstract: A 2-cycle uni-flow spark-ignition engine has an annular scavenging chamber which is communicated with a crank chamber and which is connected to scavenging ports which are opened in an end period of downward stroking of a piston. A fluid introduced into the crank chamber is pre-compressed by the downward stroking of the engine and is discharged into a cylinder chamber through the annular scavenging chamber and the scavenging ports to form a uni-flow of scavenging fluid with a swirl above the piston. The engine has an exhaust valve provided on a cylinder head and normally opened by being driven with a predetermined force exerted by driving coiled spring towards the inside of the cylinder chamber.

Abstract: A two-stroke-cycle uniflow spark-ignition engine. A fluid sucked and pressurized by a compressor driven by the engine is delivered to an annular scavenging chamber formed in a cylinder around the entire circumference thereof, so as to be accumulated therein. The fluid within the annular scavenging chamber is discharged therefrom, through a plurality of scavenging ports formed in the cylinder and capable of opening into a cylinder chamber toward the end of a descending stroke of a piston, and/or into a recess which is above the piston, the discharged fluid serving as a scavenging fluid that flows generating a swirling uniflow. A mixture compressed within the cylinder chamber during an ascending stroke of the piston is ignited by an ignition plug for combustion.

Abstract: A two-stroke-cycle uniflow spark-ignition engine generates power by pressurizing fluid introduced into a crank chamber within the crank chamber with a piston as it moves toward its bottom dead center, feeding the pressurized fluid to an annular scavenging chamber provided on the entire periphery of a cylinder where it accumulates, and discharging the fluid in the annular scavenging chamber into a cylinder chamber provided above the piston from a plurality of scavenging ports which are opened at the end of the descending stroke of the piston as a scavenging fluid in the form of a swirling uniflow.

Abstract: An internal combustion engine apparatus including an internal combustion engine having an ignition system and a centrifugal clutch. The ignition system is capable of being in delayed ignition timing in a range of low engine speeds and being in advanced ignition timing in a range of high engine speeds while quickly changing ignition timing stepwise when the engine speed is at a predetermined level between the low and high engine speed ranges, and the centrifugal clutch is switched between a condition of engagement and a condition of disengagement at an engine speed in the vicinity of the predetermined engine speed. The apparatus retains the advantages of an internal combustion engine having a centrifugal clutch and allows a machine for which the apparatus is used to make effective use of engine output power. The apparatus has improved engine startup characteristic and increased engine stability and is free from engine stall when the centrifugal clutch is not fully engaged.

Abstract: A grass trimmer has an elongated operation rod, a prime mover mounted on one end of the operation shaft, a transmission shaft extended through the operation rod, a gear box connected at its one end to the other end of the operation rod, and a cutting blade member connected to a blade driving shaft projected from the other end of the gear box, the transmission shaft and the blade driving shaft being drivingly connected to each other through gears within the gear box. The gear box 5 is composed of a plurality of steel sheets 7,8 which are shaped beforehand to define, when assembled together, a hollow 17 of a circular cross-section and to have longitudinal flanges 9,9 and 10,10. The steel sheets 7,8 are joined to each other to form the gear box in one body by hemming along the flanges 9,9 and 10,10 such that the flanges are superposed and folded one on the other to form fold-back portions 11,11 along the length of the gear box 5.

Abstract: A heat insulating mounting device for use with a carburetor of an internal combustion engine including a heat insulating casing formed of a heat insulating synthetic resinous material for enclosing the carburetor connected to a cylinder in a manner to isolate the carburetor from the heat of radiation of the engine, and a flexible air passageway of small thickness formed of a heat insulating high molecular compound of rubbery properties heat insulatingly communicating the carburetor with the cylinder.

Abstract: A 2-cycle opposed cylinder internal combustion engine of simultaneous ignition type for portable machines such as grass trimmer. Two cylinders are provided at their same sides with intake ports and exhaust ports. In each cylinder, the intake port and the exhaust port are arranged in a side-by-side relation in the direction of axis of the cylinder. Namely, exhaust port which is heated to high temperature is arranged near the intake port which is cooled during the operation of the engine. In consequence, the temperature of the portion around the exhaust port is lowered while the temperature of the portion around the intake port is raised to uniformalize the temperature distribution in the cylinder to eliminate various problems attributable to non-uniform temperature distribution in the cylinder.

Abstract: An exhaust muffler for a two-cycle opposed cylinder engine of simultaneous ignition type having two cylinders opposing to each other in the horizontal direction. The muffler has conical members disposed to oppose to exhaust ports of the cylinders, the exhaust ports being arranged in a side-by-side relation. The conical members form conical annular discharge passages leading from respective exhaust ports. The discharge passages have flattened peripheral outlets of different opening areas. The flows of the exhaust gas from respective cylinders are introduced through the flattened peripheral outlets of the discharge passages into a common diffusion chamber, so that the attenuation of the pressure waves and release of heat of exhaust gas are promoted to reduce the exhaust noise of the engine.

Abstract: An ignition system for an internal combustion engine is provided with an ignition timing retarding circuit to prevent overrunning of the engine. The ignition timing retarding circuit includes a switching circuit connected to the gate of an ignition control thyristor and a predetermined duration signal generator for generating a signal having a predetermined duration from a predetermined reference time. During the time period in which the predetermined duration signal is applied to the switching circuit, the switching circuit is maintained conductive to thereby bypass an ignition signal generated in synchronism with the crankshaft rotation and applied to the gate of the ignition control thyristor.

Abstract: A grass cutting apparatus including a belt-shaped cutter of the rectangular shape in cross section having a small thickness and pointed edges at its opposed short sides, the belt-shaped cutter being formed of a macromolecular compound and wound on a reel loosely fitted on a hub of a rotary casing.

Abstract: A cord-type mowing machine comprises a rotary head in the form of a housing containing a coil of nylon cord therein. An uncoiled end portion of the cord extends downwardly through the bottom of the housing and is fixedly secured to the housing on its underside and at a point between an axis of rotation of the rotary head and the outer periphery of the housing.

Abstract: A chain saw driven by a two-cycle opposed cylinder engine of simultaneous ignition type. The vibration energies generated in respective cylinders are offset by each other partly because the cylinders are made to oppose to each other, and partly because the ignitions of these cylinders take place simultaneously. Further, the opposed cylinder engine provides ample spaces above and below the cylinders. These spaces are conveniently used for accommodating intake system including a carburetor and so forth and exhaust system including a muffler and so forth. Sound shielding walls are disposed in the ample space around the cylinders so as to insulate the noise caused by the engine and, at the same time, to define a sufficiently large cooling air passage.

Abstract: A braking system including a sensing lever operated when the forward portion of a chain saw moves upwardly with a jerk due to a kickback phenomenon or the hand of an operator slips from a handle during operation, a brake device, and a direct-acting interlocking member connecting the sensing lever to the brake device. A force exerted on the sensing lever and a force of a spring locking the sensing lever are both transmitted to the brake device through the interlocking member.

Abstract: An engine unit enclosing an engine, a fuel tank, an oil tank and a chain driving system is mounted on a handle assembly consisting of a front handle, a rear handle and a handle connecting member interconnecting the front and rear handle and supporting the bottom of the engine unit through three vibration isolators made of an elastic material. The rear end of the handle connecting member is joined through a vibration isolator to the rear end of the rear handle, and the front upper end of the rear handle is joined through vibration isolator to the top of the engine unit. The upper end of the front handle is positioned in parallel with the upper end of the rear handle in the horizontal direction and joined thereto through a vibration isolator, and the lower end of the front handle is joined directly to the front end of the handle connecting member.

Abstract: A chain saw adapted to damp mechanical vibrations comprising a front handle attached to the front portion of the engine section through a plurality of vibration dampers made of rubber or like material, a connector made of a rigid material connected to the front handle and disposed downwardly of the engine section to extend rearwardly thereof, and a rear handle attached to the upper portion of the rear wall of the engine section through at least one vibration damper made of rubber or like material. The connector is connected at its rear end portion to the rear handle through a vibration damper made of rubber or like material and at its intermediate portion to the underside of the engine section through a vibration damper made of rubber or like material.