Abstract: An annular hose coupling is connected to a hose nipple having a hose attached thereto. The hose coupling has, on its inner peripheral surface, a non-threaded portion and a female threaded portion to be screwed onto a male threaded portion formed on a distal end portion of a suction nozzle. The non-threaded portion is located on a distal end portion of the hose coupling to be inserted over the nozzle and having such an inner diameter that the non-threaded portion is fittable over the male threaded portion of the nozzle. The hose coupling is connected to the nozzle through meshing engagement between the female threaded portion of the hose coupling and the male threaded portion of the nozzle.

Abstract: Driving power is transmitted to an output shaft, via driving and driven bevel gears, to a cutter blade. A gearbox supports the output shaft via first and second bearings. The second bearing is engaged by an engaging member to be prevented from axial movement, toward the blade, relative to the gearbox and supports the output shaft near the cutter blade. The output shaft is connected to the driven bevel gear such that it is prevented from rotation relative to the driven bevel gear but allowed to move axially. When the engaged state, by the engaging member, of the second bearing is canceled, the shaft is allowed to axially move toward the cutter blade until the shaft becomes rotatable relative to the driven bevel gear, at the same time of which a retaining stopper prevents the shaft from further axial movement.

Abstract: A transmission has a movable transmission part movably connected to a fixed transmission part via a shaft to undergo pivotal movement relative to the fixed transmission part about an axis of the shaft. Each of the transmission parts has a hollow cylindrical connecting portion through which the shaft extends. One of the connecting portion of the movable transmission part and the connecting portion of the fixed transmission part is received in the other of the connecting portions with a single seal member disposed therebetween so that an internal space of the fixed transmission part and an internal space of the movable transmission part communicate with each other to thereby form a single hermetically-sealed space for holding therein a lubricating oil.

Abstract: An operation lever structure wherein an operation lever is pulled toward a left handle to cause a link to swing-move to thereby operate an operation cable. The operation lever structure is configured so that each of inside and outside rollers are provided to an opposite end of the link. Inside and outside guide holes for movably supporting the inside and outside rollers are formed in each of a pair of inside and outside side walls. A discharge opening is formed in a bottom part of the operation lever for discharging a foreign matter that has entered the operation lever.

Abstract: Driving power is transmitted to an output shaft, via driving and driven bevel gears, to a cutter blade. A gearbox supports the output shaft via first and second bearings. The second bearing is engaged by an engaging member to be prevented from axial movement, toward the blade, relative to the gearbox and supports the output shaft near the cutter blade. The output shaft is connected to the driven bevel gear such that it is prevented from rotation relative to the driven bevel gear but allowed to move axially. When the engaged state, by the engaging member, of the second bearing is canceled, the shaft is allowed to axially move toward the cutter blade until the shaft becomes rotatable relative to the driven bevel gear, at the same time of which a retaining stopper prevents the shaft from further axial movement.

Abstract: Operation mechanism of a working machine includes a main clutch lever pivotably provided on an operating handle, and a pivot member operable in interlocked relation to pivoting operation of the main clutch lever. The pivot member pivots about a pivot point differing in position from a pivot point of the main clutch lever. When fully pulled by pivoting operation of the main clutch lever, the cable member is located nearest to the pivot point of the pivot member, so that force reverse-pivoting the pivot member is reduced.

Abstract: A handle structure of a walk-behind working machine includes: a handle having left and right raised portions extending upward from a handle frame and a cross portion interconnecting the left and right raised portions; and a main clutch lever shiftable from a clutch-OFF position to a clutch-ON position by being pivoted into pressed abutment against the cross portion. The main clutch lever is constructed in such a manner that, when the main clutch lever is in abutment against the cross portion, a space for allowing a human operator to grip the left and right raised portions is secured between the left and right raised portions and the main clutch lever.

Abstract: A transmission has a movable transmission part movably connected to a fixed transmission part via a shaft to undergo pivotal movement relative to the fixed transmission part about an axis of the shaft. Each of the transmission parts has a hollow cylindrical connecting portion through which the shaft extends. One of the connecting portion of the movable transmission part and the connecting portion of the fixed transmission part is received in the other of the connecting portions with a single seal member disposed therebetween so that an internal space of the fixed transmission part and an internal space of the movable transmission part communicate with each other to thereby form a single hermetically-sealed space for holding therein a lubricating oil.

Abstract: A handle structure of a walk-behind working machine includes: a handle having left and right raised portions extending upward from a handle frame and a cross portion interconnecting the left and right raised portions; and a main clutch lever shiftable from a clutch-OFF position to a clutch-ON position by being pivoted into pressed abutment against the cross portion. The main clutch lever is constructed in such a manner that, when the main clutch lever is in abutment against the cross portion, a space for allowing a human operator to grip the left and right raised portions is secured between the left and right raised portions and the main clutch lever.

Abstract: An operation lever structure wherein an operation lever is pulled toward a left handle to cause a link to swing-move to thereby operate an operation cable. The operation lever structure is configured so that each of inside and outside rollers are provided to an opposite end of the link. Inside and outside guide holes for movably supporting the inside and outside rollers are formed in each of a pair of inside and outside side walls. A discharge opening is formed in a bottom part of the operation lever for discharging a foreign matter that has entered the operation lever.

Abstract: Operation mechanism of a working machine includes a main clutch lever pivotably provided on an operating handle, and a pivot member operable in interlocked relation to pivoting operation of the main clutch lever. The pivot member pivots about a pivot point differing in position from a pivot point of the main clutch lever. When fully pulled by pivoting operation of the main clutch lever, the cable member is located nearest to the pivot point of the pivot member, so that force reverse-pivoting the pivot member is reduced.

Abstract: A power transmission mechanism for transmitting a driving force from a drive shaft to a driven member of a gear via a one-way clutch is provided. The one-way clutch includes a swinging clutch portion swingably fitted in a clutch portion housing groove formed in a first end portion of the drive shaft. The swinging clutch portion has a cylindrical portion as the axis of rotation and a projecting portion. When the drive shaft rotates, the projecting portion of the swinging clutch portion is raised by a slit of a collar fitted onto the drive shaft, engaging one of a plurality of engaging grooves formed in the inner peripheral surface of the driven member. When the drive shaft does not rotate, the swinging clutch portion lies down, and the projecting portion does not engage any engaging groove, allowing the driven member to rotate bidirectionally relative to the drive shaft.

Abstract: A power transmission mechanism for transmitting a driving force from a drive shaft to a driven member of a gear via a one-way clutch is provided. The one-way clutch includes a swinging clutch portion swingably fitted in a clutch portion housing groove formed in a first end portion of the drive shaft. The swinging clutch portion has a cylindrical portion as the axis of rotation and a projecting portion. When the drive shaft rotates, the projecting portion of the swinging clutch portion is raised by a slit of a collar fitted onto the drive shaft, engaging one of a plurality of engaging grooves formed in the inner peripheral surface of the driven member. When the drive shaft does not rotate, the swinging clutch portion lies down, and the projecting portion does not engage any engaging groove, allowing the driven member to rotate bidirectionally relative to the drive shaft.

Abstract: A walk-behind working machine has a drive source, wheels rotationally driven by the drive source, and a traveling clutch for transmitting driving power from the drive source to the wheels. A driving member is disposed in the case and has a first friction surface. A driven member is mounted in the case for undergoing rotation relative to the driving member and has a second friction surface positioned to be brought into surface contact with the first friction surface at a preselected surface pressure.

Abstract: A tiller includes an engine, a transmission mechanism, and a rotor shaft having tillage tines mounted thereon. The transmission mechanism transmits a motive power of the engine to the rotor shaft to thereby cause the tillage tines to perform a tilling operation. The tiller also includes a tranmission case having the transmission mechanism housed therein, and a fender disposed to cover the tillage tines. The fender is mounted to the tranmission case by bolts. Each bolt has a portion projecting downwardly from the fender. The tiller further includes a guard member extending downwardly from the transmission case to a level lower than the downwardly projecting portion of each bolt. The guard member guards the bolts against a foreign object thrown upwardly by the tillage tines during the tilling operation.

Abstract: Driving worm provided on a transmission shaft, driven worm wheel provided on a cultivating shaft, main shaft portion of the transmission shaft and clutch are collectively accommodated in a transmission casing, which includes first and second bearings for preventing the clutch and driving gear from being displaced toward each other. The main shaft portion is screw-coupled to the clutch and a direction in which the screw-coupling between the main shaft portion and the clutch is tightened corresponds to only one rotational direction of an engine. The casing has a single opening for inserting therein the worm and worm wheel, and the opening is closed with a lid that also functions to prevent the worm from coming off the casing.

Abstract: A tiller includes an engine, a transmission mechanism, and a rotor shaft having tillage tines mounted thereon. The transmission mechanism transmits a motive power of the engine to the rotor shaft to thereby cause the tillage tines to perform tilling operation. The tiller also includes a transmission case having the transmission mechanism housed therein, and a fender disposed to cover the tillage tines. The fender is mounted to the transmission case by means of bolts. Each bolt has a portion projecting downwardly from the fender. The tiller further includes a guard member extending downwardly from the transmission case to a level lower than the portion of each bolt. The guard member guards the bolts against a foreign object thrown upwardly by the tillage tines under the tilling operation.

Abstract: Driving worm provided on a transmission shaft, driven worm wheel provided on a cultivating shaft, main shaft portion of the transmission shaft and clutch are collectively accommodated in a transmission casing, which includes first and second bearings for preventing the clutch and driving gear from being displaced toward each other. The main shaft portion is screw-coupled to the clutch and a direction in which the screw-coupling between the main shaft portion and the clutch is tightened corresponds to only one rotational direction of an engine. The casing has a single opening for inserting therein the worm and worm wheel, and the opening is closed with a lid that also functions to prevent the worm from coming off the casing.

Abstract: A walk-behind working machine includes an engine, a pair of rear wheels, and a traveling clutch interposed between the engine and the rear wheels. The clutch includes a case containing lubricating oil, a driving member having a female portion, and a driven member having a male portion. The driving and driven members are submerged in the oil. The clutch provides a characteristic curve shown in a coordinate system where a vertical axis of the system shows a coefficient of friction between the female and male portions and a horizontal axis of the system shows a parameter obtained by multiplying a viscosity of the oil by the number of times the male portion rotates relative to the female portion per second, and then dividing the resulting product by a surface pressure between the female and male portions. The characteristic curve includes first and second straight lines. The first and second straight lines meet each other at a bent point.

Abstract: A tiller for cultivating soil has a power source and a tilling shaft mounted for undergoing rotation by a driving force supplied from the power source. The tilling shaft has a hollow outer shaft and an inner shaft extending through the outer shaft. The inner shaft has a variable rotating speed and/or direction of rotation relative to the outer shaft. A power transmission mechanism transmits a driving force from the power source to the tilling shaft. The power transmission mechanism has a first power transmission system for transmitting the driving force from the power source to the outer shaft and a second power transmission system transmitting the driving force from the power source to the inner shaft. The second power transmission system has a hydrostatic transmission comprised of a hydraulic pump and a hydraulic motor for effecting a stepless change of the rotating speed of the inner shaft as well as a selective change of its direction of rotation.