Abstract: A suction tube of a stratified scavenging engine that can improve the flexibility in designing the shapes and layouts of an air-fuel mixture passage and an air passage; allow for continuous and smooth changes in the shapes of the cross sections of the air-fuel mixture passage and the air passage from the inlet side toward the outlet side; reduce the number of components; and facilitate attachment and assembly; and that is also advantageous in terms of cost is provided. The suction tube includes an air-fuel mixture passage and an air passage, inlet and outlet sides of the passages being connected to a carburetor and a cylinder, respectively; a cylindrical exterior member that mainly forms an outer perimeter portion of each of the air-fuel mixture passage and the air passage; and an interior member for dividing the inside of the cylindrical exterior member into the air-fuel mixture passage and the air passage.

Abstract: A suction tube of a stratified scavenging engine that can improve the flexibility in designing the shapes and layouts of an air-fuel mixture passage and an air passage; allow for continuous and smooth changes in the shapes of the cross sections of the air-fuel mixture passage and the air passage from the inlet side toward the outlet side; reduce the number of components; and facilitate attachment and assembly; and that is also advantageous in terms of cost is provided. The suction tube includes an air-fuel mixture passage and an air passage, inlet and outlet sides of the passages being connected to a carburetor and a cylinder, respectively; a cylindrical exterior member that mainly forms an outer perimeter portion of each of the air-fuel mixture passage and the air passage; and an interior member for dividing the inside of the cylindrical exterior member into the air-fuel mixture passage and the air passage.

Abstract: Provided is a structure for preventing the falling of a fastening nut of a portable power work machine, the structure reliably preventing loss of the nut and containing assembly cost, manufacturing cost, and component cost while reducing the possibility of damage, failure or the like and increasing the nut fastening and loosening workability and durability. A nut anchor member comprises a single bent wire or bar of elastically deformable material, and includes: a split ring-shaped portion externally retained in a circular groove provided at the outer periphery of a nut; a pair of left and right leg-like piece portions continuous with both ends of the split ring-shaped portion; and hook piece portions continuous with lower portions of the leg-like piece portions. A cover includes a locking portion that locks the hook piece portions so as to prevent the nut and the nut anchor member from falling from the cover when the nut is detached from the bolt.

Abstract: Provided is a structure for preventing the falling of a fastening nut of a portable power work machine, the structure reliably preventing loss of the nut and containing assembly cost, manufacturing cost, and component cost while reducing the possibility of damage, failure or the like and increasing the nut fastening and loosening workability and durability. A nut anchor member comprises a single bent wire or bar of elastically deformable material, and includes: a split ring-shaped portion externally retained in a circular groove provided at the outer periphery of a nut; a pair of left and right leg-like piece portions continuous with both ends of the split ring-shaped portion; and hook piece portions continuous with lower portions of the leg-like piece portions. A cover includes a locking portion that locks the hook piece portions so as to prevent the nut and the nut anchor member from falling from the cover when the nut is detached from the bolt.

Abstract: A top-handle portable working machine includes a grip configuration that makes it easy for a worker to manipulate the implement as intended in order to adapt to tasks in which accuracy, fineness, or an attractive finish is needed. The direction of an axis in which the top grip extends and the direction of a working axis of the implement are inclined relative to each other in a vertical direction so as to intersect at a point to the rear of the housing at angle between 15 and 25°. A detachable grip-position restricting member is attachable to a concave part of the top grip.

Abstract: A top-handle portable working machine includes a grip configuration that makes it easy for a worker to manipulate the implement as intended in order to adapt to tasks in which accuracy, fineness, or an attractive finish is needed. The direction of an axis in which the top grip extends and the direction of a working axis of the implement are inclined from each other in a vertical direction so as to intersect at a point to the rear of the housing at angle between 15 and 25°.

Abstract: A top-handle portable working machine includes a grip configuration that makes it easy for a worker to manipulate the implement as intended in order to adapt to tasks in which accuracy, fineness, or an attractive finish is needed. The direction of an axis in which the top grip extends and the direction of a working axis of the implement are inclined relative to each other in a vertical direction so as to intersect at a point to the rear of the housing at angle between 15 and 25°. A detachable grip-position restricting member is attachable to a concave part of the top grip.

Abstract: Problems: For enhanced safety of a work apparatus with an internal combustion engine, a cutting element is prevented from an accidental run due to an accidental increase of the engine revolution while a throttle control trigger is in a released state. Solution: In an engine start period, a throttle valve (10) is in a first idling position. The engine 2 at its initial run phase does not increase in revolution because of instability of its running condition. When the running condition begins to stabilize, the revolution rapidly increases. When the engine revolution (Ne) reaches 4,000 rpm or higher, a non-firing control mode is set up. In the non-firing control mode, when the engine revolution reaches or exceeds 4,500 rpm, a non-firing processing is executed (S4). A centrifugal clutch (6) is designed to engage at 5,000 rpm.

Abstract: A top-handle portable working machine is provided with a grip configuration that makes it easy for a worker to manipulate the implement as intended in order to adapt to tasks in which accuracy, fineness, or an attractive finish is needed. The direction of an axis in which the top grip extends and the direction of a working axis of the implement are inclined from each other in a vertical direction so as to intersect at a point to the rear of the housing, and the inclination angle ? between the direction of the axis of the top grip and the direction of the working axis of the implement is set in the range of 15 to 25°.

Abstract: Problems: For enhanced safety of a work apparatus with an internal combustion engine, a cutting element is prevented from an accidental run due to an accidental increase of the engine revolution while a throttle control trigger is in a released state. Solution: In an engine start period, a throttle valve (10) is in a first idling position. The engine 2 at its initial run phase does not increase in revolution because of instability of its running condition. When the running condition begins to stabilize, the revolution rapidly increases. When the engine revolution (Ne) reaches 4,000 rpm or higher, a non-firing control mode is set up. In the non-firing control mode, when the engine revolution reaches or exceeds 4,500 rpm, a non-firing processing is executed (S4). A centrifugal clutch (6) is designed to engage at 5,000 rpm.

Abstract: There is provided a refuse-trapping cover for a portable working machine, which is capable of reducing the deterioration of the engine-cooling performance of the cooling fan that may be caused by the fibrous sawdust of a palm tree. The refuse-trapping cover includes a frame (40) having a plurality of open windows (40a-40j) and attached to the outer casing (20) of a chain saw (1) to thereby cover the air inlet slits (22), and a mesh member (50) integrally fixed to the frame (40) to thereby cover open windows (40a-40j). The frame (40) is constructed to have predetermined dimension and configuration, and the mesh member (50) is fixed to a predetermined location of the frame (40) to thereby provide a sufficient space (S) between the mesh member (50) and the outer casing (20) to avoid the mesh member (50) from being adsorbed onto the outer casing (20).

Abstract: There is provided a refuse-trapping cover for a portable working machine, which is capable of reducing the deterioration of the engine-cooling performance of the cooling fan that may be caused by the fibrous sawdust of a palm tree. The refuse-trapping cover includes a frame (40) having a plurality of open windows (40a-40j) and attached to the outer casing (20) of a chain saw (1) to thereby cover the air inlet slits (22), and a mesh member (50) integrally fixed to the frame (40) to thereby cover open windows (40a-40j). The frame (40) is constructed to have predetermined dimension and configuration, and the mesh member (50) is fixed to a predetermined location of the frame (40) to thereby provide a sufficient space (S) between the mesh member (50) and the outer casing (20) to avoid the mesh member (50) from being adsorbed onto the outer casing (20).