| All Patents in class 137/625.69 |
Patents 1 -
9
of 9
      |
| Picture | Number | Date | Patentee | Title |
| | 204,649 | Jun. 11, 1878 | R.W. Aitken | Piston-Valve for Engines |
 | 705,730 | Jul. 29, 1902 | J.T. Wilson | Balanced slide-valve |
| | 2,496,040 | Jan. 31, 1950 | W.W. Criley | Control Valve Mechanism for Clutches and Brakes |
 | 2,630,135 | Mar. 03, 1953 | C. Johnson | Fluid valve for duplicating system |
| | 2,722,889 | Nov. 08, 1955 | G.A. Wahlmark | Servo-type control for pumps |
| | 2,924,239 | Feb. 09, 1960 | S.A. Bjorklund | Servo Valve Having Helically Arranged Metering Parts |
| | 2,994,304 | Aug. 01, 1961 | W. Shultz | Hydraulic Servo Drive System for Machine Tool Elements and the Like |
| | 3,084,899 | Apr. 09, 1963 | C.L. Gschwind, L.A. Dever | Manual Three Direction Tracer |
| | 3,315,569 | Apr. 25, 1967 | L.A. Dever | Control Mechanism for Machine Tool |
