Yamabiko Corporation

Kioritz Corporation

Kunimune Kawamura

Kazuhiro Umetani

Shigeru Sato

Hidekazu Tsunoda

Kazuhiro Tsutsui

Buhei Kobayashi

Hiroshi Nakaganna

Tatsumi Uejima

Masato Nara

The rotary body according to the present invention is made of resin and attached to a crankshaft. The rotary body has an outside plate element and an inside plate element which are attached to an outside surface and an inside surface of an arm portion of the crankshaft, respectively, and a pair of filler elements disposed between the outside plate element and the inside plate element and on both sides of the arm portion. The outside plate element and the pair of the filler elements are coupled to each other, and the pair of the filler elements and the inside plate element are coupled to each other.

Rotary body

A wire throttle adjustment devicefor performing open-close adjustment of a throttle valve by pull operation of a wire. The wire throttle adjustment deviceincludes an operation memberconnected to an end partA of the wireand configured to perform the pull operation of the wire. The operation memberincludes an action partthat is elastically deformable by the pull operation of the wirein a fully-opened state of the throttle valve. The action partincludes an elastically-deformable elastic arm partconfigured to swing together with the operation partand extending from the pivotally-supported part, and the end part of the wireis connected to a tip part of the elastic arm part

Wire throttle adjustment device

A structure for preventing the falling of a fastening nut of a portable power working machine that can reliably prevent loss of the nut while suppressing the production and component costs, allows for easy operation of attaching a nut anchor member to a cover, and can increase the maintenance property, suppress damage and failures, increase the durability, and reduce the size and weight; and a method for attaching the fastening nut to a cover are provided. The structure includes a nut locking member, which is inserted through a bolt insertion hole from a back surface side of a cover so that movement of the nut locking member to a front surface side is prevented, and has a split cylindrical shape with elastically deformable leg-like piece portions; an anchoring cylindrical portion with a predetermined length functioning as a nut anchor member, the anchoring cylindrical portion being provided in a protruding manner and coaxially with the nut on a seating surface side, being adapted to be inserted through the bolt insertion hole, and being relatively difficult to elastically deform with respect to the nut locking member. A protruding end of the anchoring cylindrical portion of the nut has formed continuous therewith a hook portion that bends inward along its entire periphery. Each end of the leg-like piece portion of the nut locking member has formed continuous therewith a locking claw portion that bends outward to lock the hook portion.

Structure for preventing falling of fastening nut of portable power working machine, and method for attaching fastening nut to cover

A chainsaw includes a chainsaw body, a guide bar and a saw chain. The chainsaw body includes an oil tank, an oil pump to supply oil stored in the oil tank to a sliding portion between the guide bar and the saw chain, a first extension chamber arranged above the oil tank and a second extension chamber arranged above the first extension chamber. The oil tank communicates with the first extension chamber via a first flow path, the first extension chamber communicates with the second extension chamber via a second flow path and a vent hole communicating with the outer space is formed in the second extension chamber.

Chainsaw

In a two-stroke internal combustion engine using air for scavenging its combustion chamber (), a scavenging passage () communicating with a crankcase () and a combustion chamber () is charged first with rich air-fuel mixture generated by a carburetor, next with lean air-fuel mixture, and next with air through an in-piston passage (). The lean air-fuel mixture is generated in the in-piston passageby diluting the air-fuel mixture with the air. In each scavenging stroke to scavenge the combustion chamber (), the combustion chamber () is supplied first with the air () and next with the lean air-fuel mixture () from the scavenging passage (). The use of the lean-air-fuel mixture () next to the air () contributes to reduce acceleration failure or engine stop caused by sudden acceleration.

Two-stroke internal combustion engine and its scavenging method

A power unit for portable chain saws wherein an ignition coil is placed at a position so as to increase both the compactness and the cooling efficiency of the power unit. A coil support on which the ignition coil is supported is formed integratedly with a crank case; adjacent to an open port; and on a part of an external periphery of the flywheel, said second part being not enclosed by the air-guiding passage. The coil support extends from the crank case along a side of a muffler and forms an insulating gap from the muffler.

Power unit for portable chain saw

An air cleaner is used in a two-stroke internal combustion engine to supply an air-fuel mixture passage and a fresh air passage in a carburetor with air cleaned by an air cleaner element. The air cleaner includes an air cleaner base having an air-fuel mixture opening communicating with the air-fuel mixture passage and a fresh air opening communicating with the fresh air passage, and an air guide member provided at the air-fuel mixture opening. The air guide member is configured to curve near the air-fuel mixture opening and extend from there along the air cleaner base, and has a cross section surrounded by a peripheral wall. The air guide member defines a mixture-use air extension passage for air to be added to prepare an air-fuel mixture air-fuel mixture, which extends from a first clean air intake to the air-fuel mixture opening. Blown-back gas from the air-fuel mixture passage hits against the inner wall of the curved portion of the air guide member, and is therefore restricted to flow out of the first clean air intake and leak into the air cleaner. Thereby, harmful emissions in the exhaust gas from the two-stroke internal engine can be reduced.

Air cleaner for two-stroke internal combustion engine and method of tuning the length of air-fuel mixture passage by using the air cleaner

A saw chain tensioning mechanism for adjusting the tension in a saw chain extending around a chain guide plate includes a threaded rod member disposed adjacent to a rear end of the chain guide plate and along the longitudinal direction of the chain guide plate, a movable member engaged with the chain guide plate and adapted to be moved along the threaded rod member by a rotation of the threaded rod member, and a driving gear integral with the threaded rod member. The tensioning mechanism includes a driving gear for rotatively driving the driving gear and an operating member for manually rotating the driving gear. Manipulating the operating member changes the longitudinal position of the chain guide plate and correspondingly causes a change in a tension of the saw chain.

Saw chain tensioning mechanism

An oil pump mechanism is incorporated in a chain saw having a centrifugal clutch and a saw chain adapted to be driven through the centrifugal clutch and activated in synchronization with the centrifugal clutch to supply a lubricating oil to the saw chain. The mechanism includes a crankshaft, a clutch shoe being mounted on the centrifugal clutch and being connected in driven relation to the crankshaft, a clutch drum disposed coaxially around the crankshaft, a worm fitted on the crankshaft by insertion in a freely rotatable manner and connected in driven relation to the clutch drum to be integrally rotated with the clutch drum, a driven gear engaged with the worm, and a movable pumping element for pumping the lubricating oil. The worm has an inner portion located opposed to the crankshaft and an outer portion including a tooth region. The inner portion is made of self-lubricating resin and the outer portion is made of wear-resistant metal.

Growing community of inventors

Tokyo, Japan

Kunimune Kawamura