Control servo

A control servo for an aircraft engine control system, the control servo comprising:

• a housing including:
• a drivetrain chamber;
• a drive opening connected to the drivetrain chamber;
• and
• an output opening connected to the drivetrain chamber and spaced from the drive opening;
• a stepper motor including a drive shaft configured to extend through the drive opening into the drivetrain chamber;
• a drivetrain at least partially positioned in the drivetrain chamber, the drivetrain including:
• a first wheel configured to be connected to the drive shaft so as to be rotatable therewith;
• a second wheel spaced from the first wheel;
• a third wheel near the second wheel and configured to be rotatable therewith;
• a fourth wheel spaced from the third wheel;
• a first belt drivably connecting the first wheel and the second wheel;
• and
• a second belt drivably connecting the third wheel and the fourth wheel;
• an output shaft configured to extend through the output opening from the drivetrain chamber and configured to be connected to the fourth wheel so as to be rotatable therewith, the drivetrain being configured to drivably connect the drive shaft and the output shaft with no backlash between the drive shaft and the output shaft;
• and
• an output lever including:
• an output lever arm having opposing proximal and distal ends, the output lever being configured to be connected to the output shaft near the proximal end so as to be rotatable with the output shaft;
• and
• a friction interface near the proximal end and configured to be adjusted to set a slip friction threshold between the output lever and the output shaft,
• wherein the friction interface is configured to have a constant length in a direction of the longitudinal axis of the output shaft during adjustment of the friction interface.

A control servo for an aircraft engine control system, the control servo comprising:

• a housing including a first aperture;
• a stepper motor including a drive shaft;
• a drivetrain drivably connected to the drive shaft and including a wheel having central rotational axis and a second aperture offset from the central rotational axis;
• an output shaft drivably connected to the drivetrain, wherein the drivetrain is configured to drivably connect the drive shaft and the output shaft;
• and
• an output lever including:
• an output lever arm having opposing proximal and distal ends, the output lever being configured to be connected to the output shaft near the proximal end so as to be rotatable with the output shaft;
• and
• a friction interface near the proximal end and configured to be adjusted to set a slip friction threshold between the output lever and the output shaft,
• wherein the drivetrain is configured to be locked in place for testing the slip friction threshold between the output lever and the output shaft, the first aperture and the second aperture being configured to be aligned for receiving a locking member therethrough for locking the drivetrain.