Abstract: A starter which is capable of smoothly and reliably starting an internal combustion engine even though an electric motor employed is relatively small in size and output, thereby making it possible to minimize power consumption of the electric motor, to miniaturize the capacity of battery, to reduce the total weight of the starter, to enhance the durability of the starter, and to suppress the generation of failure of the starter. This starter comprises a buffering/power-accumulating means disposed midway along a power transmission system between a driving member and a driven member, wherein the buffering/power-accumulating means is enabled, during the driving process, to accumulate the power supplied through the driving process while alleviating any impact to the driven member, the accumulated power being subsequently employed to drive the driven member, and wherein the driving member is an electric motor.

Abstract: A cooling system for an OHC type four-stroke cycle internal combustion engine having a valve chamber lubricated by oil mist. The system includes an accommodating space accommodating a transmission mechanism, a blower fan rotatably driven by a crankshaft, and a cooling air channel extending between a combustion chamber and the valve chamber disposed above the combustion chamber. The cooling air channel includes a primary air channel formed between intake and exhaust ports and extends toward a spark plug located on the downstream side of the cooling air channel. The cooling air channel also includes an air guide channel for guiding the air to an upstream inlet of the primary air channel and is defined by a wall which faces the upstream inlet of the primary air channel and extends laterally. The wall extends vertically in the accommodating space and is formed with an oil mist passage extending vertically therein.

Abstract: A muffler for an internal combustion engine is disclosed which is capable of effectively enhancing its muffling effect without any substantial increase in size, weight or manufacturing cost. The exhaust gas ejected from an exhaust port of the internal combustion engine is divided in the muffler into at least two flows. The divided exhaust gas flows are subsequently impinged against each other before the divided exhaust gas flows are finally discharged from a final exhaust port to the external atmosphere. More specifically, this muffler comprises an expansion chamber into which the exhaust gas is to be introduced from the exhaust port, and the expansion chamber is provided with at least two impingement openings for enabling the exhaust gas to be divided into at least two exhaust gas flows which are designed to be subsequently impinged against each other.

Abstract: A reciprocating pump which is capable of detecting abnormalities in the sucking and discharging of fluid, such as the exhaustion of oil or the clogging of oil on the discharge side, by making use of detecting means which is inexpensive and relatively simple in structure and which can be operated without being detrimentally influenced by the bubbles that may be included in the fluid, while making it possible to minimize the noise generated by external vibrations. In this reciprocating pump, where the sucking and discharging of fluid are effected by making use of a reciprocating member, malfunction-detecting means formed of a piezoelectric element is provided for detecting a pressure fluctuation on a discharge side of the pump, and the pressure fluctuation of fluid being delivered from an discharging port is transmitted via a rigid pressure-receiving member to the piezoelectric element.

Abstract: There is provided a method for manufacturing a cylinder for an internal combustion engine by making use of an insert core, which makes it possible to manufacture the cylinder by a die casting method such as a high-pressure die casting method at low cost and in high accuracy.

Abstract: A cylinder for an internal combustion engine and a method for treating the inner surface of the cylinder, which enables the inner surface constituting a piston-sliding surface of the cylinder to have a high quality plated layer which is uniform in thickness and smooth in surface at low cost without necessitating grinding work such as honing work. The cylinder and the method of the present invention are characterized in that the inner surface of the cylinder is provided with a plated layer which is deposited thereon by a PR (Periodical Reverse) method employing a high-speed polarity reversal power source.

Abstract: A cylinder and a method for manufacturing a cylinder for an internal combustion engine is provided which avoids the generation of a step portion at the scavenging port without necessitating enhanced precision of the positioning of the working tools or the working location. A raw cylinder body is cast-molded with the scavenging port portion thereof being left closed. Subsequently, this closed scavenging port portion is cut out (or opened) by means of cutting work, etc. The cutting out of the closed scavenging port portion is performed by widening the cylinder bore side thereof at predetermined angles to the planes of the inner wall of the hollow scavenging passageway formed contiguous to the closed scavenging port portion.

Abstract: A recoil starter having a driving member and a driven member, wherein the driving member further includes recoiling unidirectional rotating means. The recoiling unidirectional rotating means includes a movable locking claw member which is supported by one of the rope reel and the interlocking rotor in such a manner that it is rotatable therewith and movable in a direction along the rotational axis thereof, an urging member for urging the movable locking claw member toward the other of the rope reel and the interlocking rotor, and an engaging member mounted on the other of the rope reel and the interlocking rotor.

Abstract: The present invention is directed to split bodies for assembling a synthetic resin blower fan by a hollow article molding process. The split bodies have a first split body which includes a circular base portion and vanes extending radially and a second split body assembled on top of said first split body and is in a doughnut-shaped cap with an air inlet at the center thereof. Air channels are formed between adjacent pair of the vanes. The second split body includes a plurality of grooves which are formed on an inner surface opposite from the first split body in an assembled state. Each of the grooves extends radially along an edge of a corresponding vane and is adapted to be closed by the edge so as to define a flow path for allowing a molten synthetic resin to pass therethrough.

Abstract: The present invention relates to a four-stroke cycle internal combustion engine in which lubrication oil is atomized to generate oil mist so as to lubricate an internal mechanism of the engine with the oil mist. The four-stroke cycle internal combustion engine includes an oil-mist breather in fluid communication with a fuel tank of the engine. Any oil mist remaining after the lubrication of the internal mechanism is discharged into the fuel tank 14 through the oil-mist breather 22. Since no oil mist remains in the oil-mist breather the air filter of the engine is not contained by the oil mist.

Abstract: There is provided a cylinder for an internal combustion engine, wherein the inner wall surface of the cylinder which constitutes a slide-contacting surface for the piston is treated with a metal plating which is minimal in burden to the environment, excellent in abrasion resistance and hard enough to endure the practical use of the cylinder, thus making it possible to dispense with a finishing work such as honing work. A method for treating the inner wall surface of the cylinder so as to obtain such a cylinder is also provided. The cylinder as well as the method are featured in that the inner wall surface of the cylinder which is adapted to be slidably contacted with a piston is electroplated in a plating bath comprising an iron plating solution containing a boron compound such as trimethylamine borane, dimethylamine borane, etc.

Abstract: There is provided a recoil starter which is capable of inhibiting settling and bending in the spiral spring of spiral spring mechanism, thus improving the durability of the spiral spring and preventing the internal hook end of the spiral spring from being easily disengaged from the core portion. The spiral spring mechanism comprises a spiral spring case placed close to the driving member, a actuating pulley placed close to the driven member, a spiral spring interposed between the spiral spring case and the actuating pulley, and means for rotating the spiral spring case only unidirectionally, wherein the outer and inner ends of the spiral spring are fastened to the spiral spring case and the actuating pulley, respectively.

Abstract: A power transmission device is disclosed which is capable of easily, swiftly and appropriately altering the distance between the axes of a pair of transmission wheels such as pulleys, enabling an endless belt to be kept under constant and appropriate tension without necessitating a tension roller. This power transmission device comprises an endless belt wound around a pair of transmission wheels; and a cam-type adjusting mechanism which is interposed between a driving side supporting member and a driven side supporting member and configured to adjust a distance between the axes of the wheels. This cam-type adjusting mechanism comprises a supporting shaft secured to either the driving side supporting member or the driven side supporting member and disposed parallel to the rotational axes of the wheels; and a cam rotatably secured via a manipulating boss member to the supporting shaft.

Abstract: A two-stroke internal combustion engine which is capable of minimizing the quantity of blow-by or the quantity of air-fuel mixture to be discharged without being utilized for the combustion, of improving the fuel consumption and power of the engine, of reducing the content of poisonous components in the exhaust gas, and of reducing the manufacturing cost, without extensively altering the conventional engine. A through-hole or a communication groove is provided at the skirt portion of a piston to thereby enabling a scavenging inlet port to be communicated with the crank chamber. In the descending stroke, combustion exhaust gas from the combustion actuating chamber is enabled to be introduced, via a scavenging outlet port provided at a downstream end of the scavenging passageway, into the scavenging passageway while closing the scavenging inlet port at the skirt portion of the piston.

Abstract: An air-preintroduction type two-stroke internal combustion engine which is capable of minimizing the quantity of blow-by, thus making it possible to improve the fuel consumption and to reduce the content of poisonous components in the exhaust gas, and is also capable of reasonably and compactly arranging the peripheral components of engine, thereby making it possible to reduce the number of parts, to lighten the weight thereof, to save the manufacturing cost thereof, and to simplify the working and assembling thereof. Specifically, this internal combustion engine is characterized in that an air inlet passageway for introducing air into the scavenging passageways is provided inside a wall portion of the cylinder.

Abstract: A portable power working machine (10) is disclosed, which is capable of effectively improving the performance thereof to cool the internal combustion engine (20), and also capable of preventing an air cleaner (30) of the air intake system of the internal combustion engine (20) from being clogged with dust. This portable power working machine is characteristic in that it comprises a guiding wall (28) disposed on one side of a main housing (12) and at a location rear to a cooling fan (25) and projected inward therefrom for guiding cooling air toward the cylinder (21) of the internal combustion engine (20); an intake passageway (50) formed at a location rear to the cooling fan (25) for introducing air into an air-intake system (30, 34, 35) of the internal combustion engine (20); and an air-intake port (55) for the intake passageway (50), the air-intake port (55) being positioned in the vicinity of a root portion (28a) of the rear face of the guiding wall (28).

Abstract: A recoil starter for a backpack-type power working machine which is capable of easily and smoothly performed the starting operation even when the working machine is kept on the operator's back irrespective of differences in the operator's build. This recoil starter comprises a recoil grip which is attached to a distal end portion of a recoil rope extended out of the main body of the recoil starter, wherein the recoil grip is designed such that it can be anchored to a recoil grip-supporting member to be positioned close to an operator's waist and that it can be pulled out in front of the operator from the recoil grip-supporting member. The recoil grip-supporting member is made optionally alterable in position.

Abstract: A chain saw with vibration-isolating devices, capable of providing a desirable vibration-isolating effect over a wide frequency range and reducing accidental deviation from a desired cutting line in a cutting operation. The chain saw includes a main body containing an engine, a frame member mounting a grip handle thereon, and at least two vibration-isolating devices each interposed between the main body and the frame member to support the main body with respect to the frame member. Two of the vibration-isolating devices are disposed spaced apart from each other in the longitudinal direction of the chain saw. Each of the two vibration-isolating devises includes a pair of first and second vibration=isolating members which are different in frequency range for providing a vibration-isolating effect. The two vibration-isolating devices are disposed such that the respective first or second vibration-isolating members are positioned in a first or second diagonal relationship with respect to one another.

Abstract: A portable trimmer in which the power generated by an internal combustion engine is transmitted to a cutter via a centrifugal clutch and the output power of the internal combustion engine is controlled by operating a manual throttle lever, thereby adjusting the throttle opening of a throttle valve via a throttle wire. The portable trimmer includes a friction member arranged to face the clutch drum of the centrifugal clutch, a moving member which is connected to the friction member and moves the friction member between a braking position where the friction member is pressed against the clutch drum and a non-braking position where the friction member is kept away from the clutch drum so as to release the braking, a manual release device for moving the moving member from the braking position to the non-braking position, and a release restricting device for controlling the behavior of the manual release device.

Abstract: A two-cycle internal combustion engine which is capable of inhibiting air-fuel mixture from being mixed with the air introduced in advance into the combustion actuating chamber during the scavenging period, thereby realizing a complete lamellar scavenging.