| All Patents in class 346/4 |
Patents 46 -
58
of 58
      |
| Number | Date | Patentee | Title | Type |
| 1,426,735 | Aug. 22, 1922 | C.E. Reddig, W.F. Hendry | Method and Apparatus for Recording Pressure | pressure indicators |
| 1,447,913 | Mar. 06, 1923 | W.C. Duryea, A. Trowbridge | Recording Indicator | pressure indicators |
| 1,490,223 | Apr. 15, 1924 | T. Midgley, Jr. | Indicator | pressure indicators |
| 1,492,754 | May 06, 1924 | J.H. Sheats | Engine Indicator | internal combustion engine indicators |
| 1,511,574 | Oct. 14, 1924 | E.H. Mortsell | Indicating and Recording Instrument | internal combustion engine indicators |
| 1,539,978 | Jun. 02, 1925 | G.B. Vroom | Chronograph | steam engine indicators |
| 1,655,615 | Jan. 10, 1928 | P. Kreisel | Recording and Timing Device for Combustion Engines | internal combustion engine indicators |
| 1,773,240 | Aug. 19, 1930 | A. Reid | Internal Combustion and Other Fluid Pressure Engine Indicator | internal combustion engine indicators |
| 1,890,601 | Dec. 13, 1932 | C.E. Cox | Internal Combustion Indicator | internal combustion engine indicators |
| 2,251,976 | Aug. 12, 1941 | G.W. Brown | Indicator for Internal Combustion Engines | internal combustion engine indicators |
| 2,365,227 | Dec. 19, 1944 | C. Unterberg | Engine Operation Analyzer | internal combustion engine indicators |
| 2,645,118 | Jul. 14, 1953 | J.H. Andresen | Power-Time Recorder | internal combustion engine indicators |
| 2,869,962 | Jan. 20, 1959 | R.C. Baird | Self-Synchronizing Horse Power Indicator | internal combustion engine indicators |
