Linear compressed air metering device

Claim 1

A LINEAR COMPRESSED AIR METERING DEVICE COMPRISING A CASING OPEN AT ONE END, A LONGITUDINAL PASSAGE IN SAID CASING CONNECTING TO SAID OPEN END, A COMPRESSED AIR INLET PORT IN SAID CASING, A COMPRESSED AIR OUTLET PORT IN SAID CASING, SAID PORTS CONNECTING THE LONGITUDINAL PASSAGE TO THE ATMOSPHERE, AN AIR CHAMBER IN SAID CASING INTERMEDIATE THE LENGTH OF SAID PASSAGE, SAID CHAMBER HAVING INLET AND OUTLET MEANS, A STEM MEMBER EXTENDING THROUGH THE OPEN END OF THE CASING AND ALONG THE LONGITUDINAL LENGTH OF SAID PASSAGE AND AIR CHAMBER, A COMPRESSION SPRING FIXED ON THE UPPER END OF SAID STEM AND BASING SAID STEM TOWARDS THE OPEN END OF THE CASING, ADJUSTMENT MEANS ON SAID STEM FOR REGULATING SAID COMPRESSION SPRING, A FIRST VALVE ON SAID STEM NORMALLY ADJACENT SAID COMPRESSED AIR INLET PORT AND SEALING THE OPEN END OF THE CASING, A SECOND VALVE NORMALLY SEATED IN SAID AIR CHAMBER INLET MEANS AND SEALING THE CHAMBER FROM RECEIVING AIR UNDER PRESSURE AND A THIRD VALVE MEMBER ON SAID STEM NORMALLY ADJACENT SAID AIR CHAMBER OUTLET MEANS AND SPACED FROM SAID AIR CHAMBER OUTLET MEANS, WHEREBY DOWNWARD MOVEMENT OF SAID STEM UNSEATS THE SECOND VALVE TO ADMIT AIR UNDER PRESSURE INTO SAID CHAMBER AND SEATS THE THIRD VALVE TO TRAP A METERED AMOUNT OF AIR IN SAID CHAMBER AND UPWARD MOVEMENT OF SAID STEM RELEASING THE AIR FROM SAID CHAMBER THROUGH THE AIR CHAMBER OUTLET MEANS WHILE SEALING THE AIR INLET MEANS.