Air motor

An air motor including:

• a first working chamber;
• a first piston at least aiding in enclosing the first chamber;
• a second working chamber;
• a second piston at least aiding in enclosing the second chamber;
• a central valve assembly including a base of unitary construction with a first valve cavity and a second valve cavity, a first movable valve member slidably located in the first cavity, a second movable valve member slidably located in the second valve cavity, each valve member being movable between a first position and a second position, inlet ducting to deliver compressed air to the first cavity, outlet ducting to exhaust air from the second cavity, intermediate ducting between the first and second cavities, and fourth ducting providing for the flow of air between said second cavity and said chambers, an inlet face to which said inlet ducting extends, and an outlet face to which said outlet ducting extends;
• an outlet port member sealingly attached to the base at said outlet face, the outlet port member having an outlet port passage communicating with the outlet ducting so that air leaving the outlet ducting is delivered to the outlet port passage;
• an inlet port member sealingly attached to the base at said inlet face, the inlet port member having an inlet port passage communicating with the inlet ducting and to which a supply of compressed air is delivered so that compressed air is delivered to the inlet ducting;
• a connecting member connecting the pistons so that the pistons reciprocate in unison;
• and wherein
• said chambers are located on opposite sides of said base so that said base is located between the chambers, said first valve member is moved between the first and second positions thereof by the pistons, and the intermediate ducting provides for the delivery of compressed air from said first cavity to said second cavity to move said second valve member between the first and second positions thereof so that the valve members are moved between the first and second positions thereof in a co-ordinated manner to provide for the delivery of the compressed air to the chambers and exhaust of the air from the chambers to thereby drive the pistons.