Air-operated hammer

An air-operated hammer, comprising

• a hammer head;
• a frame;
• an air flow control valve;
• a pressurized air reservoir, wherein lifting of the hammer head is assisted by pressurized air from the pressurized air reservoir and wherein said pressurized air reservoir receives pressurized air from a pressurized air source during at least a portion of the period of time the hammer head is dropping, wherein said air flow control valve comprises an inlet valve for allowing pressurized air to enter the bottom portion of the cylinder and assist in raising the hammer head, and an exhaust valve for allowing air to exit the bottom portion of the cylinder, wherein a valve comprising two seats functions as both the inlet valve and the exhaust valve, such that in a first position, the inlet valve is open and the exhaust valve is closed, and in a second position, the inlet valve is closed and the exhaust valve is open;
• a means for actuating the air flow control valve from the first position to the second position and from the second position to the first position, wherein said means for actuating the air flow control valve from the first position to the second position and from the second position to the first position is an automatic control valve system fed by pressurized air;
• and
• a minimum pressure valve coupled between an air supply and the automatic control valve system, wherein pressurized air is supplied to said automatic control valve system only when the air supply;
• reaches a minimum operating pressure.