Abstract: The invention relates to an auto tensioner of a chain saw. A spiral guide groove (16) of the disk (15) engages with a protrusion 10a of a slider piece (10) and the slider piece (10) is slidably stored in a guide portion (9) formed in a chain cover (2) via a spring (14). A tensioner (11) comprising a protrusion (11) engaged with a guide bar is slidably stored in the slider piece 10 via a coin spring (12). The protrusion (10a) contacts an outer circumference face of the spiral guide groove 16 on a diameter passing through a rotating center of the disk, and an unshown nut for engaging with a stud bold 6 provided on an engine cover side is attached on the rotating center of the disk (15). A rotation of the disk enables to fix the chain cover (2) and move the guide bar.

Abstract: A chain saw as a portable work machine includes: a body in which an engine is accommodated; a carburetor accommodated in a top handle for generating air-fuel mixture to be supplied to the engine; an air cleaner provided on a lateral side of the body; and an intake communication passage that intercommunicates between the air cleaner and the carburetor.

Abstract: A cable terminal includes: a crimped portion crimped to a cable body; an extending piece provided integrally with the crimped portion to extend forward in an insertion direction; and a conductor conducting piece provided integrally with the crimped portion to face an end face of the cable body. An end of the extending piece abuts on an inner surface of a plug cap made of an elastic body to determine a position in terms of the insertion direction. The extending piece is provided with a springy press piece that projects to a plug terminal of an ignition plug inserted into the plug cap and contacts an end face of the plug terminal. The conductor contacting piece is sandwiched between a portion of an outer circumference of the plug terminal and a core exposed from the end face of the cable body. The plug terminal is disposed to be in tight contact with the inner surface of the plug cap.

Abstract: A portable-blower duct has a bendable portion whose inner peripheral surface is a cylindrical surface without any protrusions or recesses in a normal state or in an expanded state, that is, unless it is greatly curved. With this construction, no turbulence is generated in air passing through a tube, thereby making it possible to suppress pressure loss. Thus, the flow velocity of air guided through the duct is not reduced, thereby suppressing a deterioration in air blowing efficiency. Even when the tube is curved, the outer side of the curved portion is expanded, and the corresponding portion of the inner peripheral surface remains a smooth surface, thus making it possible to minimize the air pressure loss.

Abstract: The invention relates to an auto tensioner of a chain saw. A spiral guide groove (16) of the disk (15) engages with a protrusion 10a of a slider piece (10) and the slider piece (10) is slidably stored in a guide portion (9) formed in a chain cover (2) via a spring (14). A tensioner (11) comprising a protrusion (11) engaged with a guide bar is slidably stored in the slider piece 10 via a coin spring (12). The protrusion (10a) contacts an outer circumference face of the spiral guide groove 16 on a diameter passing through a rotating center of the disk, and an unshown nut for engaging with a stud bold 6 provided on an engine cover side is attached on the rotating center of the disk (15). A rotation of the disk enables to fix the chain cover (2) and move the guide bar.

Abstract: This invention provides a battery pack for driving a compact electric motor of a compact engine starting device mounted on a working machine, comprising lithium-based secondary battery comprising two cells, the entire discharge capacity of the cells being 500 to 2000 mAh, charging voltage per one cell being 3.0 to 4.2 V, various electronic circuits like driving and battery protection circuits of an electric motor, maximum discharge current of the battery having high rate of 10 to 60 A, the protection circuit including an overdischarge inhibit circuit (A) interposed in the electric motor driving circuit and automatically stopping the driving operation of the electric motor after time required for starting the engine elapsed, the volume of the battery pack being as extremely low as 2.5×104 to 1.0×105 mm3, the tire required until the engine is started from the actuation of the electric motor being set to an interval as short as 5 to 15 seconds, since high current can flow.

Abstract: A chainsaw includes: a body case 20 in which an engine for driving the chainsaw is accommodated; and a top handle 41 provided on an upper side of the body case 20. A fuel tank 7 for storing fuel of the engine is integrally provided to the top handle 41. A carburetor 6 is also provided to the top handle 41. The fuel tank 7 is disposed near the carburetor 6.

Abstract: Through holes formed on an atomization pipe can prevent fuel adhering on inner walls of the through holes from escaping. In addition, when fuel adhering on an inner circumferential surface of the atomization pipe flows toward a downstream side, the fuel enters the through holes. Thus, the fuel can be confined therein Furthermore, an absorbing member can absorb the fuel that has adhered to a downstream inner wall of the atomization pipe and flows toward the downstream side. Moreover, a periphery of the intake passage hole of a gasket protrudes from the inner wall, so that flow of the fuel that the absorbing member fails to absorb toward the downstream side can be blocked. Accordingly, a rapid increase in the amount of fuel flowing into the engine body can be reliably prevented. Therefore, fluctuation in the number of revolutions of the engine can be sufficiently restrained.

Abstract: A transmissible connecting mechanism drives a lead air control valve and an air-fuel mixture throttle valve of a carburetor of a stratified scavenging two-cycle engine in an interlocking manner. A cam plate having a cam groove is attached to an end portion of a valve shaft of the lead air control valve, and a lever is attached to a valve shaft of an air-fuel mixture throttle valve arranged within a carburetor main body. A contact element engaging with the cam groove of the cam plate is arranged in the lever. The lead air control valve and the throttle valve are urged in a valve closing direction by springs. A cam mechanism serving as the transmissible connecting mechanism is structured by the cam plate and the lever.

Abstract: A muffler of a work machine in the form of an engine blower includes: a muffler body; and a diffuser that covers an exhaust outlet of exhaust gas provided on the muffler body. The diffuser has a diffusion space to diffuse the exhaust gas and an exhaust surface on which a plurality of exhaust circular holes are provided to exhaust the exhaust gas to an outside. An opening ratio provided by the exhaust holes of the exhaust surface is gradually increased from a portion corresponding to the exhaust opening toward an outer periphery of the exhaust surface.

Abstract: The present invention relates to a start device for a small-sized engine, which is capable of starting the small-sized engine in an appropriate starting time and is ultimately reduced in size and weight by a rational design. A plurality of secondary batteries is used as a power source required to drive a small-sized electric motor and a small-sized engine, and has a considerably large capacity and an extremely small size. A speed reduction mechanism that has a reduction ratio of 1/30 to 1/90 is disposed between the electric motor and a buffer/power storage section. The start device starts the engine in an extremely short time of 0.4 to 1.3 seconds. Within this range of staring time of the engine, an operator has no uncomfortable feelings.

Abstract: A chain saw includes a body in which an engine for driving a saw chain is laterally housed; a top handle provided above the body; and a muffler arranged below the engine, in which an exhaust outlet for discharging exhaust from the body side to the outside opens forward from the body side. Accordingly, not only the exhaust can be discharged forward from the side of the body, but also the exhaust sound can be propagated forward so that less exhaust sound is heard by the operator, thereby improving the work environment.

Abstract: The invention relates to an auto tensioner of a chain saw. A spiral guide groove (16) of the disk (15) engages with a protrusion 10a of a slider piece (10) and the slider piece (10) is slidably stored in a guide portion (9) formed in a chain cover (2) via a spring (14). A tensioner (11) comprising a protrusion (11) engaged with a guide bar is slidably stored in the slider piece 10 via a coin spring (12). The protrusion (10a) contacts an outer circumference face of the spiral guide groove on a diameter passing through a rotating center of the disk, and an unshown nut for engaging with a stud bolt 6 provided on an engine cover side is attached on the rotating center of the disk (15). A rotation of the disk enables to fix the chain cover (2) and move the guide bar.

Abstract: A transmissible connecting mechanism having a cam plate and a lever are attached respectively to a lead air control valve shaft and an air-fuel mixture throttle valve shaft which are arranged so as to form an angle. A length of a contact element provided in the lever is extended in parallel to an axis of the air-fuel mixture throttle valve shaft, and the length of the contact element is such that the contact element and a cam surface formed in a cam plate are always brought into contact with each other. The lead air control valve shaft and the air-fuel mixture throttle valve shaft of the carburetor are connected in a transmissible manner, and it is possible to make a stratified scavenging two-cycle engine compact.