Abstract: The present invention relates to a chain saw having a chain bar portion extending forwardly from a main body. The chain saw comprises an attaching portion to which a suspension member is to be attached, and the attaching portion is arranged in the vicinity of a corner portion, where a back surface and a bottom surface of the main body meet with each other, so that a longitudinal center axis of the chain bar portion may be at an angle of not greater than 20 degrees from a vertical line.

Abstract: The present invention relates to a brake band for use with a centrifugal clutch. The brake band is formed in a curved strip shape to be disposed along the outer peripheral surface of a clutch drum of the centrifugal clutch, and is adapted to be tightened around or released from the outer peripheral surface in response to the movement of at least one end of the brake band. The brake band comprises a plurality of linings provided on the inner surface thereof to be opposed the outer peripheral surface of the clutch drum. The linings are located spaced apart from each other along the longitudinal direction of the brake band.

Abstract: There is provided a portable power working machine, which is capable of rationally and effectively preventing the generation of the icing without giving rise to early clogging of air cleaner, the malfunction of a internal combustion engine and deterioration of performance. This working machine comprises a small air-cooled internal combustion engine which is mounted inside a main housing, a cooling fan disposed on one side of the main housing; a carburetor coupled to an upper portion of an intake port of the internal combustion engine; a clean air chamber disposed on an upstream side of the carburetor; an air cleaner cover coupled to the clean air chamber; a warm air introducing passageway for introducing, through a region adjacent to the intake port, part of air which has been sucked by the cooling fan for cooling the internal combustion engine into the air cleaner cover; and a shutter for and externally opening or closing the warm air introducing passageway as desired.

Abstract: A disk cleaner includes a polishing member that is rotated while it is pressed against a surface of a disk to be polished to thereby polish the surface of the disk and an air cooling apparatus that cools the disk by causing outside air to flow along the surface of the disk. The air cooling apparatus is incorporated integrally with the disk cleaner. The cooling apparatus inhibits the peeling of the adhered surfaces as well as the generation of cracks of a DVD of a two-ply structure.

Abstract: The present invention is directed to a method for joining two parts together and the unit derived therefrom. The method comprises the steps of mating a first flange portion extending along an entire periphery of a first part with a second flange portion extending along an entire periphery of a second part; overfolding a margin portion extending along an outer edge of the second flange portion to join the first part and the second part; a linear ridge being formed on at least one of the first flange portion, the second flange portion and the margin portion, the linear ridge extending along an entire periphery of the at least one portion and extending toward the first flange portion, the second flange portion or the margin portion which is opposed to the linear ridge in the overfolded state; and compressing the margin portion to plastically deform the linear ridge so as to form a seal between the two parts.

Abstract: The present invention provides a set of split bodies for forming a synthetic-resin blower fan through a hollow-article injection molding process, wherein the blower fan integrally includes a circular base, a doughnut-shaped cover portion having an air inlet opening at the center thereof, and a plurality of blades each extending radially between the circular base and the inner surface of the cover portion to define a plurality of radial airflow passages between the adjacent blades. The set of split bodies comprises a first split body including the circular base and a plurality of blade members, and a second split body defining the inner surface of the cover portion and having an outer surface on the opposite side of the first split body.

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 gases, and is also capable of reasonably and compactly arranging the peripheral components of the 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. The engine is characterized in that an air inlet passageway for introducing air into the scavenging passageways of the engine is provided at a mating face between the cylinder and the crankcase of the engine.

Abstract: A two-stroke internal combustion engine is disclosed capable of reducing the number of pieces constituting the main body, thereby making it possible to reduce the number of parts such as assembling bolts and hence to reduce the manufacturing cost as well as the weight thereof while ensuring the rigidness of the main body. The main body of the engine includes a cylinder portion in which a piston is adapted to be fittingly inserted and a crankcase portion in which a crank shaft is rotatably supported via a bearing wherein the crankcase portion is constructed such that it is split into an upper and a lower crankcase portion by a horizontal plane which passes through a central axial line of the crankshaft, where the upper crankcase portion is integrated with the cylinder portion, thus forming an integral cylinder-case, and a fan case base is formed integral with the lower crankcase portion.

Abstract: A recoil starter includes a rotary driving member that is adapted to be rotated by pulling a recoil rope and an interlocking rotary member that is adapted to be rotated independently of the rotary driving member. A buffering spring is coupled between the rotary driving member and the interlocking rotary member. The buffering spring, which may be a torsion coil spring or a spiral spring, applies a rotational bias between the rotary driving member and the interlocking rotary member and is adapted to transmit the rotation of the rotary driving member to the interlocking rotary member.

Abstract: A portable trimmer capable of applying to a throttle valve a different operation from that according to a throttle operation lever. The portable trimmer includes a brake device for braking the movement of a cutting blade that is released in conjunction with a throttle operation. The portable trimmer includes a throttle wire having a first throttle wire extending between a throttle operation lever and a swingable member, and a second wire portion extending between a swingable member and a throttle to provide a first operation transmission path for transmitting the movement of the throttle operation lever to the throttle valve. The portable trimmer further includes an additional operation lever for performing a different operation from said throttle operation, and a pulley pivotally attached to the swingable member.

Abstract: A power supply apparatus for electrostatic charging sprayed liquids from a spraying apparatus and method for same, the apparatus including a rotor having a magnet and magnetic poles, a booster coil assembly facing the rotor, for inducing high voltage AC pulses during the rotation of the rotor, and a rectifier for rectifying the high voltage AC pulses induced by the booster coil assembly to high voltage DC pulses and for supplying the high voltage DC pulses to a charging electrode. The power supply apparatus provides a compact and lightweight power generator system, thus eliminating cumbersome operations such as replacement or recharging of a large battery. In addition, a lighter weight and simplified operation reduces the burden on users and facilitates more efficient spraying.

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: 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. The cylinder is 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 a nickel plating solution containing a boron compound such as trimethylamine borane, dimethylamine borane, etc.

Abstract: The present invention provides a working machine having an internal combustion engine. The working machine includes a single operation unit comprised of a rotatable body adapted to be selectively rotated between an engine-stop position, engine-start position and choke-activation position, a valve to be rotated about an rotation shaft, an arm attached to the rotation shaft and a link member adapted to be moved in its longitudinal direction to transmit the movement of the rotatable body to the arm. The link member has a distal end coupled with the arm and a proximal end coupled with the rotatable body, and extends between the distal and proximal ends. The rotatable body is formed with an elongated slot receiving the proximal end therein. When the rotatable body is rotated from the engine-stop position to the engine-start position, the proximal end is allowed to displace relative to the rotatable body along the elongated slot without causing any movement of the link member in the longitudinal direction.

Abstract: The present invention provides a chain saw having a high degree of safety for its various positions including an upward and a downward position. The chain saw comprises a bar-shaped top handle extending in a lengthwise direction above an upper surface of a main body and a bar-shaped side handle provided next to a left side surface of the main body. When the main body is seen in a plan view, a front end portion of the side handle is intersected transversely with and coupled to a left side surface of a front end portion of the top handle. A right-side support surface extending outwardly in the transverse direction is provided on a right side surface of the front end portion of the top handle. It is located substantially at the same position as a left-side support surface which is comprised of a rear surface of the front end portion of the side handle in the lengthwise direction of the main body.

Abstract: An engine cutter which is simple in structure and low in manufacturing cost. This engine cutter comprises a disk cutter, an air-cooled internal combustion engine for rotating the disk cutter, a safety cover partially encasing the disk cutter, and a dust-trapping portion which is mounted on the safety cover for trapping and discharging dust to be generated from a cutting work by the disk cutter; and is characterized in that only single fan to be driven by the engine is provided not only for generating an air flow for sucking and discharging the dust that has been trapped in the dust-trapping portion but also for generating a cooling air flow for cooling the internal combustion engine.

Abstract: A four-stroke cycle internal combustion engine in which an oil reservoir for storing lubricating oil is arranged below a crank chamber housing a crankshaft, and oil mist formed in the oil reservoir is supplied to the interior of the crank chamber and to a valve chamber through an oil mist passage for providing fluid communication between the oil reservoir and the valve chamber. The oil mist passage includes a pre-separation oil mist passage section formed in the crankshaft, a cylindrical centrifugal-separation chamber surrounding the outer-periphery of the crankshaft, a post-separation oil mist passage section extending from the centrifugal-separation chamber in the opposite direction of the rotational direction of the crankshaft and in fluid communication with the valve chamber, and an oil return passage providing fluid communication between the centrifugal-separation chamber and the oil reservoir.

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 starter which is capable of having an operator easily perform the starting operation of a backpack-type power working machine while shouldering it, is lighter in weight and cheaper in manufacturing cost, is relatively free from trouble, and can not easily be damaged even if a portion of the starter is caught by the branch of a tree. In this starter, a recoil handle attached to one end portion of the recoil rope is placed remote from the main body of the starter by a predetermined distance and adapted to be supported by a handle-supporting member provided at a specific portion of the working machine; and an extended portion of the recoil rope which is located between the main body and the handle-supporting member is loosely sheathed by a flexible guide pipe, one end of which being fixed, and the other end being made free.

Abstract: The present invention relates to a cooling system for an OHC type four-stroke cycle internal combustion engine in which a valve chamber is lubricated by oil mist. This cooling system includes an accommodating space accommodating a transmission mechanism for transmitting the rotational movement of a crankshaft to a camshaft in the valve chamber, a blower fan rotatably driven by the 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. The cooling air channel 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. The air guide channel is defined by a wall which faces the upstream inlet of the primary air channel and extends laterally.