| # | Country | Total Patents | |
|---|---|---|---|
| #1 | Germany | 8 | |
| #2 | United States | 3 | |
| #3 | Austria | 1 | |
| #4 | Switzerland | 1 | |
| #5 | EPO (European Patent Office) | 1 | |
| #6 | United Kingdom | 1 |
| # | Industry | |
|---|---|---|
| #1 | Engines, pumps and turbines | |
| #2 | Thermal processes | |
| #3 | Mechanical elements | |
| #4 | Environmental technology | |
| #5 | Transport |
| # | Technology | |
|---|---|---|
| #1 | Internal-combustion piston engines | |
| #2 | Machines | |
| #3 | Clutches and brakes | |
| #4 | Rotary pistons | |
| #5 | Refrigerators | |
| #6 | Cycles | |
| #7 | Climate change mitigation in buildings | |
| #8 | Gearing | |
| #9 | Rotary-pistons | |
| #10 | Burners |
| # | Name | Total Patents |
|---|---|---|
| #1 | Groll Robert C | 12 |
| #2 | Robert C Groll | 1 |
| Publication | Filing date | Title |
|---|---|---|
| EP0102555A1 | Rotary piston machine | |
| DE3324994A1 | Rotary piston machine | |
| DE3303123A1 | Process for increasing the performance factor of heat pumps or refrigerators which circulate gas (air) as working medium | |
| DE3129133A1 | Method and device for operating a heat pump, an air-conditioning installation or the like | |
| DE3039536A1 | PISTON MACHINE | |
| DE2846516A1 | Reaction engine for vehicles - has opposed pistons in common cylinder with unequal resistances to produce net forward force | |
| US3060999A | Oil burner | |
| GB800712A | A stepless variable-speed transmission | |
| US2268448A | Pressure creating apparatus |