A transmission comprising a shaft (6) made as a single piece or as at least two shaft sections (6A, 6B) on a common axis, a drive toothed wheel (5) mounted to rotate freely on said shaft (6), and an automatically clutching clutch mechanism (8) arranged between the drive wheel (5) and the shaft (6) or each of the shaft sections (6A, 6B), the or each clutch mechanism (8) comprising: a clutch plate (81) mounted to rotate freely on the associated shaft (6) or shaft section (6A, 6B); a part (82) that is carried by and constrained to rotate with the associated shaft (6) or shaft section (6A, 6B); and a brake of said clutch plate that acts continuously on the angular speed of said plate (81). The brake (83) of the at least one of the clutch plates (81) is threaded on the shaft (6) or the shaft section (6A, 6B) carrying said plate (81).

A lawn mower (10) may include a blade housing (20), an engine (30), a mobility assembly (310); and a drive system (300). The engine (30) may be operably coupled to the blade housing (20) and configured to selectively rotate a drive shaft (130). The mobility assembly (310) may include a first set of wheels (40, 42) and be selectively operably coupled to the engine (30) to provide mobility of the lawn mower responsive at least in part to operation of the engine (30). The drive system (300) may include a first transmission (110, 120), a flexible driving member (100), a disengagement assembly (116), and a remote actuator. The a disengagement assembly (116) may include a latching lever (125), where the latching lever (125) is configured to switch the first transmission (110, 120) between a disengaged mode and an engaged mode, and where the latching lever (125) is configured to move between a disengaged position corresponding to the disengaged mode and an engaged position corresponding to the engaged mode. The remote actuator may be operably coupled to the flexible driving member (100), where responsive to actuation of the remote actuator, the flexible driving member (100) engages a) the latching lever (125) to move the latching lever (125) to the engaged position to thereby place the first transmission (110, 120) in the engaged mode; and b) the first transmission (110, 120) to provide drive power from the drive shaft (130) to the first set of wheels (40, 42).

A transmission speed control system for a walk-behind lawn mower includes a transmission, a transmission positioning assembly, and an electronic control unit. The transmission is tiltable about and operably engaged with a drive axle shaft. The transmission positioning assembly tilts the transmission between first and second angular positions. A belt tension between a drive belt and a transmission pulley of the transmission continuously increases from a minimum belt tension when the transmission is in the first angular position to a maximum belt tension when the transmission is in the second angular position. The rotational drive force exerted on the drive axle shaft by the transmission and a resulting driving speed of the lawn mower vary proportionally with the belt tension. The electronic control unit controls the transmission positioning assembly to tilt the transmission based on target and detected driving speeds.

A transmission includes an output shaft, a first gear rotatably mounted on the output shaft, a shuttle movably axially on the output shaft, and an engagement member fixedly mounted on the output shaft. The first gear includes first dog teeth. The shuttle includes second dog teeth which engage the first dog teeth. In a drive condition, the engagement member axially moves the shuttle into engagement with the first gear, first surfaces of the first and second dog teeth engage, and, as a result, the first gear rotates in together with the output shaft. In a freewheeling condition the output shaft is stationary, an overdrive of the first gear results in engagement of second surfaces of the first and second dog teeth, and, as a result, the shuttle moves out of engagement with the first gear allowing for free rotation of the first gear about the output shaft.

An outdoor power equipment unit such as, e.g., a walk-behind lawnmower including a frame, a power head, and a hydrostatic transmission, wherein the hydrostatic transmission includes a drive gear configured to rotate about a first axis. The unit also includes a pair of rear drive wheels coupled at respective ends of a rear drive axle, wherein the rear drive axle is operably coupled to a driven gear. The pair of rear drive wheels, the rear drive axle, and the driven gear are configured to rotate about a second axis. A drive chain is operably coupled to both the drive gear and the driven gear. Furthermore, a wheel height adjustment mechanism is provided, wherein the wheel height adjustment mechanism includes a first bell crank pivotally coupled to the frame about the first axis, with a first end of the first bell crank being coupled to the rear drive axle. A control assembly for controlling the speed and direction of the outdoor power equipment unit is also disclosed.

A transmission for a manually operated wheeled machine includes an output shaft having a close-ended axial channel. A drive gear mounted on the output shaft includes an engaging groove. A ratchet is received in the channel and is in engagement with the engaging groove. A holder mounted on the output shaft includes a relief that receives the ratchet. A friction member applies radial friction to the holder to temporarily prevent rotation of the holder with the output shaft in a drive condition of the machine moving the ratchet into engagement with the engaging groove, and in the drive condition the drive gear and holder rotate with the output shaft. In a freewheeling condition of the machine the output shaft is stationary, and an overdrive of the drive gear disengages the ratchet from the engaging groove allowing for free rotation of the drive gear about the stationary output shaft.

Transmission housing (1) having a body (2) formed by two shells (2A, 2B) and comprising a rotary input shaft (4) and an output shaft (5), the rotary input shaft (4) comprising a driving end (6) and a threaded portion (7) and having mounted on it a rolling-element bearing (8) arranged between the threaded portion (7) and the driving end (6), said housing (1) creating, inside the enclosure (3), a station (12) for receiving the rolling-element bearing (8) and a station (13) for receiving the threaded portion (7). The housing (1) comprises a barrier (14) positioned between said stations (12, 13), this barrier (14) extending around said input shaft (4), creating a through-passage (15) for access for the input shaft (4) from one station (12) to the other (13), this barrier (14) being formed in at least two portions (16, 17), each barrier portion (16, 17) being produced in a single piece with the associated shell (2A, 2B), at least one of the barrier portions (16, 17) being shaped so as to create at least one deflector (161) formed at least partially by an inclined surface having a slope that descends from the body (2) of the housing (1) towards the input shaft (4), when the input shaft (4) is positioned vertically with the rolling-element bearing (8) extending above the threaded portion (7) of the input shaft (4).

A transmission speed control system for a walk-behind lawn mower includes a transmission, a transmission positioning assembly, and an electronic control unit. The transmission is tiltable about and operably engaged with a drive axle shaft. The transmission positioning assembly tilts the transmission between first and second angular positions. A belt tension between a drive belt and a transmission pulley of the transmission continuously increases from a minimum belt tension when the transmission is in the first angular position to a maximum belt tension when the transmission is in the second angular position. The rotational drive force exerted on the drive axle shaft by the transmission and a resulting driving speed of the lawn mower vary proportionally with the belt tension. The electronic control unit controls the transmission positioning assembly to tilt the transmission based on target and detected driving speeds.

A transmission includes an output shaft, a first gear rotatably mounted on the output shaft, a shuttle movably axially on the output shaft, and an engagement member fixedly mounted on the output shaft. The first gear includes first dog teeth. The shuttle includes second dog teeth which engage the first dog teeth. In a drive condition, the engagement member axially moves the shuttle into engagement with the first gear, first surfaces of the first and second dog teeth engage, and, as a result, the first gear rotates in together with the output shaft. In a freewheeling condition the output shaft is stationary, an overdrive of the first gear results in engagement of second surfaces of the first and second dog teeth, and, as a result, the shuttle moves out of engagement with the first gear allowing for free rotation of the first gear about the output shaft.

A transmission for a manually operated wheeled machine includes an output shaft having a close-ended axial channel. A drive gear mounted on the output shaft includes an engaging groove. A ratchet is received in the channel and is in engagement with the engaging groove. A holder mounted on the output shaft includes a relief that receives the ratchet. A friction member applies radial friction to the holder to temporarily prevent rotation of the holder with the output shaft in a drive condition of the machine moving the ratchet into engagement with the engaging groove, and in the drive condition the drive gear and holder rotate with the output shaft. In a freewheeling condition of the machine the output shaft is stationary, and an overdrive of the drive gear disengages the ratchet from the engaging groove allowing for free rotation of the drive gear about the stationary output shaft.