Abstract: A bi-directional locking ring assembly is provided comprising a housing and a gear having a plurality of teeth. The gear is coupled to the housing to rotate in opposite directions about a rotational axis. A pin is also coupled to the housing and has an apex configured to travel along a line that does not pass through the rotational axis of the gear. The pin is configured to translate between (1) a disengaged position wherein the gear is free to rotate, and (2) an engaged position wherein the apex resides between two of the plurality of teeth to prevent rotation of the gear in both rotational directions. A pin actuator is coupled to the housing and configured to engage the pin to selectively lock the pin in the engaged position.

Abstract: A drive shaft is configured to be disposed between a drive mechanism and a plurality of driven mechanisms and to transfer a drive torque generated by the drive mechanism to one of the plurality of driven mechanisms. The drive shaft includes a first shaft section and a second shaft section. The first shaft section has a first outer diameter, and is dimensioned to be disposed within the drive mechanism, within one of the plurality of driven mechanisms, or simultaneously within the drive mechanism and one of the plurality of driven mechanisms. The first shaft section is also configured to at least selectively engage, and thereby at least selectively receive the drive torque generated in, the drive mechanism. The second shaft section is coupled to the first shaft section and has a second outer diameter that is less than the first outer diameter. The second shaft section is dimensioned to be disposed within either the drive mechanism or one of the plurality of driven mechanisms.

Abstract: A turbofan gas turbine propulsion engine includes a multi-speed transmission between the high pressure and low pressure turbines and associated high pressure and low pressure starter-generators. The multi-speed transmission reduces the operating speed range from the low pressure turbine to its associated starter-generator, and is configurable to allow the starter-generator associated with the low pressure turbine to supply starting torque to the engine.

Abstract: A bi-directional locking ring assembly is provided comprising a housing and a gear having a plurality of teeth. The gear is coupled to the housing to rotate in opposite directions about a rotational axis. A pin is also coupled to the housing and has an apex configured to travel along a line that does not pass through the rotational axis of the gear. The pin is configured to translate between (1) a disengaged position wherein the gear is free to rotate, and (2) an engaged position wherein the apex resides between two of the plurality of teeth to prevent rotation of the gear in both rotational directions. A pin actuator is coupled to the housing and configured to engage the pin to selectively lock the pin in the engaged position.