A motor arrangement for a pneumatic tool includes a motor cylinder
defining a motor chamber, an inlet passage adapted to receive a flow of
motive fluid, forward and reverse passages communicating with the motor
chamber, a throttle port, and at least one exhaust port. A motor rotor
rotates in a forward direction in response to motive fluid flowing into
the motor chamber from the forward passage and in a reverse direction in
response to motive fluid flowing into the motor chamber from the reverse
passage. A valve actuates to selectively place one of the forward and
reverse passages in communication with the inlet passage for the
provision of motive fluid from the inlet passage to the selected one of
the forward and reverse passages. A throttle mechanism including a
throttle actuator extends through the throttle port and is actuable to
control the flow of motive fluid through the inlet passage.