A gear system for a rotary wing aircraft includes a first gear including an inner gear portion having a first pitch and an outer gear portion having a second pitch that is distinct from the first pitch. A second gear includes a third pitch driven at a driving rotational speed. An actuator member is coupled to the second gear while driven at the driving rotational speed. The actuator member shifts the second gear along the first gear to engage with one of the inner gear portion and the outer gear portion to drive the first gear at a first rotational speed and engage with other one of the inner gear portion and the outer gear portion to drive the first gear at a second rotational speed. A controller is operable to control the actuator member to shift the second gear between the inner gear portion and the outer gear portion.

A gear system for a rotary wing aircraft includes a first gear including an inner gear portion having a first pitch and an outer gear portion having a second pitch that is distinct from the first pitch. A second gear includes a third pitch driven at a driving rotational speed. An actuator member is coupled to the second gear while driven at the driving rotational speed. The actuator member shifts the second gear along the first gear to engage with one of the inner gear portion and the outer gear portion to drive the first gear at a first rotational speed and engage with other one of the inner gear portion and the outer gear portion to drive the first gear at a second rotational speed. A controller is operable to control the actuator member to shift the second gear between the inner gear portion and the outer gear portion.

This invention relates to a drive system which automatically disengages when a loading above a certain threshold limit is applied to the driven component, thus preventing damage to the drive system and foremost to the gearing between the drive system and the driven component when such a load is applied.

A bicycle drive system includes a front face gear, a rear face gear, a drive shaft, and a front roller-toothed gear assembly coupled to the first end of the drive shaft, and a rear roller-toothed gear assembly coupled to the second end of the drive shaft. Both the front roller-toothed gear assembly and the rear roller-toothed gear assembly include one or more roller elements. The roller-toothed gear assemblies are advantageous in ensuring the bicycle drive system is highly efficient, and is only minimally or not at all affected by dirt, water, contaminants, or other foreign matter typically experienced in un-clean riding conditions.

This invention relates to a drive system which automatically disengages when a loading above a certain threshold limit is applied to the driven component, thus preventing damage to the drive system and foremost to the gearing between the drive system and the driven component when such a load is applied.

A bicycle drive system includes a front face gear, a rear face gear, a drive shaft, and a front roller-toothed gear assembly coupled to the first end of the drive shaft, and a rear roller-toothed gear assembly coupled to the second end of the drive shaft. Both the front roller-toothed gear assembly and the rear roller-toothed gear assembly include one or more roller elements. The roller-toothed gear assemblies are advantageous in ensuring the bicycle drive system is highly efficient, and is only minimally or not at all affected by dirt, water, contaminants, or other foreign matter typically experienced in un-clean riding conditions.

A drive unit includes a wheel distribution gear mechanism for driving two output wheels as a function of the direction of rotation. An intermediate wheel, which meshes with a drive wheel of the wheel distribution gear mechanism, is movably guided on a circular path that is concentric with respect to an axis of rotation of the drive wheel, so as to reach a first driving position, meshing with a first output wheel, during rotation in a first direction of rotation, and a second driving position, meshing with a second output wheel, during rotation in an opposite second direction of rotation.