An aspect of the present invention provides a speed reducer including a supporting block, an input gear rotatably supported on the supporting block, an intermediate gear meshing with the input gear, an output gear meshing with the intermediate gear, and a gear position changing mechanism configured to change a position of the intermediate gear relative to the input and output gears.

A dual reciprocating blade landscape saw is operably connected to a rotatable shaft of an input device. The landscape saw includes a worm assembly having a lower housing and a worm disposed therein, the worm operably connected to the rotatable shaft of the input device and having a spiral thread, a worm gear assembly having an upper housing and a worm gear disposed therein, the worm gear having a disk comprising a cutout and a plurality of outer teeth engaged with the spiral thread of the worm, and a pair of blades coupled to opposing sides of the worm gear. The rotatable shaft of the input device drives the worm of the worm assembly. Rotational motion of the worm transfers to the worm gear to permit the pair of blades coupled thereon to move linearly in a reciprocating sequence.

A dual reciprocating blade landscape saw is operably connected to a rotatable shaft of an input device. The landscape saw includes a worm assembly having a lower housing and a worm disposed therein, the worm operably connected to the rotatable shaft of the input device and having a spiral thread, a worm gear assembly having an upper housing and a worm gear disposed therein, the worm gear having a disk comprising a cutout and a plurality of outer teeth engaged with the spiral thread of the worm, and a pair of blades coupled to opposing sides of the worm gear. The rotatable shaft of the input device drives the worm of the worm assembly. Rotational motion of the worm transfers to the worm gear to permit the pair of blades coupled thereon to move linearly in a reciprocating sequence.

A gearbox is provided comprising a planetary gearbox with a ring gear, sun wheel and planetary wheel carrier, on which at least one planetary wheel is mounted in a rotatable manner and is engaged via teeth with the ring gear and sun wheel; a first axially shiftable coupling sleeve, which in first gear position disconnects an input shaft to the gearbox from the planetary wheel carrier, and in a second gear position connects the input shaft with the planetary wheel carrier; and a second axially shiftable coupling sleeve, which in the first gear position connects a gearbox house surrounding the planetary gearbox with the ring gear, and in the second gear position disconnects the gearbox house from the ring gear. An axial stop, mounted on the planetary wheel carrier, abuts against and is connected with the ring gear and prevents the ring gear from shifting axially.

An assembly for an aircraft propulsion system includes an output shaft and a gear assembly. The gear assembly is configured to drive rotation of the output shaft. The gear assembly includes a sun gear, a plurality of planet gears, a first ring gear, and a second ring gear. The sun gear is rotatable about a rotational axis. The sun gear includes a first double helical gear pattern. Each planet gear of the plurality of planet gears includes a main gear, a first lateral gear, and a second lateral gear. The main gear includes a second double helical gear pattern engaged with the first double helical gear pattern. The first lateral gear is engaged with the first ring gear. The second lateral gear is engaged with the second ring gear. The first ring gear is axially spaced from the second ring gear relative to the rotational axis.

An assembly for an aircraft propulsion system includes an output shaft and a gear assembly. The gear assembly is configured to drive rotation of the output shaft. The gear assembly includes a sun gear, a plurality of planet gears, a first ring gear, and a second ring gear. The sun gear is rotatable about a rotational axis. The sun gear includes a first double helical gear pattern. Each planet gear of the plurality of planet gears includes a main gear, a first lateral gear, and a second lateral gear. The main gear includes a second double helical gear pattern engaged with the first double helical gear pattern. The first lateral gear is engaged with the first ring gear. The second lateral gear is engaged with the second ring gear. The first ring gear is axially spaced from the second ring gear relative to the rotational axis.

A marine transmission located within drive housing includes a torque transmitting gear set and a clutch mechanism. The torque transmitting gear set includes top and bottom bevel gears and opposing side idler bevel gears mounted to a pinion shaft. The pinion shaft is mounted on a carrier and the clutch mechanism engages the carrier to rotate with the input shaft to drive the output shaft in the forward direction and engages the carrier to a reaction plate fixed to the drive housing to drive the output shaft in the reverse direction.

A marine transmission located within drive housing includes a torque transmitting gear set and a clutch mechanism. The torque transmitting gear set includes top and bottom bevel gears and opposing side idler bevel gears mounted to a pinion shaft. The pinion shaft is mounted on a carrier and the clutch mechanism engages the carrier to rotate with the input shaft to drive the output shaft in the forward direction and engages the carrier to a reaction plate fixed to the drive housing to drive the output shaft in the reverse direction.

A transmission has an input member, an output member, at least four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes actuatable in combinations of three to establish a plurality of forward gear ratios and at least one reverse gear ratio.

A gearbox is provided comprising a planetary gearbox with a ring gear, sun wheel and planetary wheel carrier, on which at least one planetary wheel is mounted in a rotatable manner and is engaged via teeth with the ring gear and sun wheel; a first axially shiftable coupling sleeve, which in first gear position disconnects an input shaft to the gearbox from the planetary wheel carrier, and in a second gear position connects the input shaft with the planetary wheel carrier; and a second axially shiftable coupling sleeve, which in the first gear position connects a gearbox house surrounding the planetary gearbox with the ring gear, and in the second gear position disconnects the gearbox house from the ring gear. An axial stop, mounted on the planetary wheel carrier, abuts against and is connected with the ring gear and prevents the ring gear from shifting axially.