Abstract: A suction tube unit connected between a cylinder block and a carburetor in a stratified scavenging engine has a suction tube for mixture made of an elastic material; and a suction tube for stratified scavenging air made of an elastic material. The suction tube for mixture and the suction tube for air have, at respective inlet ends connected to the carburetor, respective wall portions which face each other and have complementary shapes. A clearance space is provided between the wall portions of the suction tube for mixture and the suction tube for air.

Abstract: A suction tube unit connected between a cylinder block and a carburetor in a stratified scavenging engine has a suction tube for mixture made of an elastic material; and a suction tube for stratified scavenging air made of an elastic material. The suction tube for mixture and the suction tube for air have, at respective inlet ends connected to the carburetor, respective wall portions which face each other and have complementary shapes. A clearance space is provided between the wall portions of the suction tube for mixture and the suction tube for air.

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).

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: 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 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 carburetor is supported on a casing by the air-fuel mixture discharging port thereof and by the portion of the adjustment screws thereof. A first vibration isolating member is interposed between the casing and the air-fuel mixture discharging port, and a second vibration isolating member is interposed between the casing and the adjustment screws. These vibration preventing members prevent the direction transmission of the vibration of the casing to the carburetor side. A reasonable and compact carburetor support structure can be provided because the air-fuel mixture discharging port and the adjustment screws are intrinsically provided with the carburetor itself.

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: 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: A cutting blade safety cover for covering a rear portion of a cutting blade of a portable trimmer. The safety cover includes a roof plate portion and a skirt portion suspended from the roof plate portion. The roof plate portion is separated at a radially middle location thereof into a radially inner portion and a radially outer portion. The radially inner portion and the radially outer portion are detachably attached to each other so that the radially outer portion is replaceable with another radially outer portion having a dimension suitable for covering a cutting blade of a different dimension.

Abstract: A carburetor is supported on a casing by the air-fuel mixture discharging port thereof and by the portion of the adjustment screws thereof. A first vibration isolating member is interposed between the casing and the air-fuel mixture discharging port, and a second vibration isolating member is interposed between the casing and the adjustment screws. These vibration preventing members prevent the direction transmission of the vibration of the casing to the carburetor side. A reasonable and compact carburetor support structure can be provided because the air-fuel mixture discharging port and the adjustment screws are intrinsically provided with the carburetor itself.

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 cutting operation. The chain saw includes a main body containing an internal combustion engine which has a crankshaft extending in the lateral direction of the chain saw, a saw chain extending from the main body in the forward direction of the chain saw, 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 devices includes a pair of first and second vibration-isolating members which are different in frequency range for providing a vibration-isolating effect.

Abstract: A portable power working machine which is provided with an internal combustion engine (20) and is designed to minimize the clogging of an air cleaner (31) attached to the air intake system of internal combustion engine (20). For this purpose, part of air introduced into the main housing (12) by means of the cooling fan (25) is allowed to be sucked again by the cooling fan, thereby enabling it to be recirculated through the carburetor chamber (40) and a circulating air duct (50) disposed outside the carburetor chamber (40), and at the same time, part of air introduced into the carburetor chamber (40) is allowed to be introduced from the air cleaner (31) into the internal combustion engine (20).

Abstract: A cutting blade safety cover for covering a rear portion of a cutting blade of a portable trimmer. The safety cover includes a roof plate portion and a skirt portion suspended from the roof plate portion. The roof plate portion is separated at a radially middle location thereof into a radially inner portion and a radially outer portion. The radially inner portion and the radially outer portion are detachably attached to each other so that the radially outer portion is replaceable with another radially outer portion having a dimension suitable for covering a cutting blade of a different dimension.

Abstract: A portable power working machine includes a small air-cooled internal combustion engine, a cooling fan, and a carburetor chamber housing therein an air cleaner. A dust-separating air duct is interposed between a region close to the cooling fan and the carburetor chamber housing, the dust-separating air duct being configured to separate dust included in an intake air from air by taking advantage of an air flow, thereby allowing clean air separated from the dust to be fed to the carburetor chamber housing and allowing the dust separated from the intake air to be sucked by the cooling fan.

Abstract: A hand lever apparatus (throttle lever) (10) is provided which has an automatic restoring function (automatic idle rotation opening position restoring function) to cope with an accident and which can perform normal operation lightly and swiftly. The hand lever apparatus (10) has a rotationally operable operating lever (30) and a toggle mechanism (T). The operating lever (30) is operated to actuate, through the toggle mechanism (T), a cable (20) connected to a driven member (CV) so as to pull the cable (20).

Abstract: A hand lever apparatus (throttle lever) is provided which has the automatic restoring function (automatic idle rotation opening position restoring function) to cope with accidents and steadily hold a desired operation position (intermediate opening position of a throttle valve). The hand lever apparatus has a rotationally operable main lever (30) and a sub-lever (40) rotationally operated to pull a cable (10a) connected to a driven member (CV). The main lever (30) has a brake plate (34). By pressing the brake plate (34) against an operating portion (42) of the sub-lever (40), rotation of the sub-lever (40) is regulated to hold the sub-lever (40) in a position.

Abstract: A hand lever device is adapted so that a throttle valve as a driven member can be adjusted appropriately in its degree of opening via a cable and kept at a desired degree of opening and yet immediately returned to the minimum degree of opening. The throttle valve can be brought to the degree of opening at which it had stood before it was returned to the minimum opening degree without the necessity of readjustment. The hand lever device comprises a main lever (30) and a sub-lever (60) which ice pivotally operated, wherein the sub-lever (60) is adapted to draw a cable (20) connected to a driven member (CV) via a pulley (50), and wherein the pulley (50) is moved by the main lever (30).