Thomas J. Langenfeld
95Patents
20h-index
18Co-inventors
85Inventor score
Filing activity: Nov 20, 1998 → Dec 28, 2020
Most-cited inventions
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US6122996A | Hydrostatic transmission | Emerging Cross-Sectional Technologies | 102 | Expired |
| US6672058B1 | Zero turn transaxle | Mechanical Engineering; Lighting; Heating | 76 | Expired |
| US7134276B1 | Cylinder block brake for a hydrostatic drive apparatus | Mechanical Engineering; Lighting; Heating | 61 | Expired |
| US6701825B1 | Return to neutral device for a hydraulic apparatus | Mechanical Engineering; Lighting; Heating | 46 | Expired |
| US6843056B1 | Zero turn transaxle | Performing Operations; Transporting | 42 | Expired |
| US6811509B1 | Hydraulic motor apparatus including brake mechanism | Mechanical Engineering; Lighting; Heating | 36 | Expired |
| US7841176B1 | Zero turn transaxle | Performing Operations; Transporting | 33 | Active |
| US7127889B1 | Zero turn transaxle | Mechanical Engineering; Lighting; Heating | 32 | Expired |
| US6374604B1 | Hydrostatic transmission bypass latch | Performing Operations; Transporting | 29 | Expired |
| US6370876B1 | Axle driving apparatus having an improved hydraulic fluid bypass mechanism | Mechanical Engineering; Lighting; Heating | 28 | Expired |
| US7225617B1 | Bypass mechanism for a hydraulic drive apparatus | Performing Operations; Transporting | 27 | Expired |
| US6811510B1 | Hydraulic motor apparatus and vehicle | Mechanical Engineering; Lighting; Heating | 26 | Expired |
| US6964164B1 | Return to neutral device for a hydraulic apparatus | Mechanical Engineering; Lighting; Heating | 26 | Expired |
| US6253637A | Control device for hydrostatic apparatus | Emerging Cross-Sectional Technologies | 26 | Expired |
| US8464610B1 | Drive device | Emerging Cross-Sectional Technologies | 25 | Active |
| US7308790B1 | Adjustable hydraulic motor apparatus | Mechanical Engineering; Lighting; Heating | 25 | Expired |
| US7047736B1 | Zero turn transaxle | Mechanical Engineering; Lighting; Heating | 24 | Expired |
| US7028708B1 | Combined check valve and pressure relief valve | Emerging Cross-Sectional Technologies | 24 | Expired |
| US8534060B1 | Drive device | Mechanical Engineering; Lighting; Heating | 21 | Active |
| US7367353B1 | Combined check valve and pressure relief valve | Emerging Cross-Sectional Technologies | 21 | Expired |
| US7111545B1 | Return to neutral device for a hydraulic apparatus | Mechanical Engineering; Lighting; Heating | 20 | Expired |
| US7328576B1 | Zero turn transaxle | Performing Operations; Transporting | 20 | Active |
| US8313408B1 | Drive assembly | Mechanical Engineering; Lighting; Heating | 20 | Active |
| US7454908B1 | Zero turn transaxle | Performing Operations; Transporting | 17 | Active |
| US8245509B1 | Zero turn transaxle | Performing Operations; Transporting | 16 | Active |
Source: USPTO / EPO open patent data. Inventor disambiguation is heuristic; counts are objective bibliographic measures.