Servo device, especially for reversing gears in motorboats

Abstract From the Canadian patent

A servo device is disclosed intended for amplifying the force in a mechanical control apparatus movable in two opposite, directions when said apparatus is displaced in either direction comprising two gears rotatably disposed in a housing and coaxial with a rotatable shaft. The gears are driven in counter-rotation by a conical pinion or by two counter-rotating cylindrical pinions in driving relation to a rotatable servo motor. A nut is screwably arranged on screw splines on the shaft between the gears. When screwed along said splines the nut comes into, frictional contact via annular friction surfaces with corresponding annular surfaces on the gears. The nut the splines and, one of the gears …