Air starter engagement system

A method of starting an engine with an engine starter, the method comprising:

• pressurizing a motor supply chamber with a fluid;
• selectively pressurizing an actuating chamber to an initial pressure in response to the pressure in the motor supply chamber;
• moving a first valve along a first axis in response to pressure in the actuating chamber;
• moving a pinion toward engagement with the engine in response to movement of the first valve;
• further pressurizing the actuating chamber to a pressure above the initial pressure;
• moving a second valve along a second axis in response to the further pressurizing the actuating chamber;
• rotating the pinion in response to movement of the second valve;
• meshing pinion teeth with teeth on the engine;
• and
• starting the engine in response to rotation of the pinion.

An engine starter operable to initiate operation of an engine under the influence of motive fluid from a source of motive fluid, the engine starter comprising:

• a motor operable under the influence of the motive fluid to operate a gear train;
• a motor supply chamber in constant communication with the source of motive fluid;
• a first valve including a first working surface and a first stem extending along a first valve axis, the first valve being supported for movement along the first valve axis between retracted and extended positions;
• a pinion coupled to the first valve, a first portion of the pinion being in meshing engagement with the gear train and a second portion of the pinion adapted to move out of engagement with respect to a portion of the engine in response to the first valve being in the retracted position and into engagement with respect to a portion of the engine in response to the first valve being in the extended position, the pinion rotating in response to the motor driving rotation of the gear train;
• a second valve including a second working surface facing the first working surface and second stem extending along a second valve axis that is collinear with the first valve axis, the second valve being supported for movement along the second axis between open and closed positions;
• a sealing member within the motor supply chamber and coupled for movement with the second valve, the sealing member closing communication between the motor supply chamber and the motor in response to the second valve being in the closed position, and opening communication between the motor supply chamber and the motor in response to the second valve being in the open position;
• an actuating chamber at least partially defined by the first and second working surfaces;
• a master valve operable between an open condition in which the master valve opens communication between the source of motive fluid and the actuating chamber, and a closed condition in which the master valve closes communication between the source of motive fluid and the actuating chamber and places the actuating chamber in communication with exhaust;
• a first biasing member biasing the first valve toward the retracted position, the first biasing member deflecting in response to a first force applied to the first valve;
• and
• a second biasing member biasing the second valve toward the closed position, the second biasing member deflecting in response to a second force applied to the second valve, the second force being higher in magnitude than the first force;
• wherein actuating the master valve into the open condition pressurizes the actuating chamber with motive fluid;
• wherein exposure of the motive fluid to the first and second working surfaces initially gives rise to the first force on the first valve, resulting in deflection of the first biasing member and movement of the first valve from the retracted position toward the extended position;
• wherein cessation of movement of the first valve toward the extended position and the pressure of motive fluid in the actuating chamber give rise to the second force against the second working surface, resulting in deflection of the second biasing member and movement of the second valve from the closed position toward the open position, such that the sealing member opens communication between the motor supply chamber and the motor;
• and
• wherein opening communication between the motor supply chamber and the motor causes the motor to operate under the influence of the motive fluid to drive rotation of the gear train and rotation of the pinion to initiate operation of the engine.