| All Patents in class 91/441 |
Patents 1 -
9
of 9
      |
| Number | Date | Patentee | Title | Type |
| 1,763,142 | Jun. 10, 1930 | W. Ernst | Hydraulic Press | hydraulic presses |
| 1,851,622 | Mar. 29, 1932 | W. Ernst | Valve Mechanism for Hydraulic Presses | hydraulic presses |
| 1,892,568 | Dec. 27, 1932 | W. Ernst | Surge Valve for Hydraulic Presses or the Like | hydraulic presses |
| 1,895,710 | Jan. 31, 1933 | H.F. MacMillin, W. Ernst | Hydraulic Press | hydraulic presses |
| 1,899,678 | Feb. 28, 1933 | R. Thoreson, H.F. MacMillin, W. Ernst | Hydraulic Press | hydraulic presses |
| 1,956,758 | May 01, 1934 | W. Ernst | Hydraulic Press Operating Circuits | hydraulic presses |
| 2,077,894 | Apr. 20, 1937 | I. Patrick | Surge control valve for hydraulic presses | hydraulic metalworking presses |
| 2,152,837 | Apr. 04, 1939 | E. Cannon | Prefill valve for hydraulic presses | hydraulic metalworking presses |
| 2,502,547 | Apr. 04, 1950 | C.E. Adams | Hydraulic apparatus | |
