Portable handheld work apparatus having a four-stroke engine
US6167874A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 1999 |
| Grant date | Jan 2, 2001 |
| Priority date | — |
| Expiry date | Dec 7, 2019 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02B2075/027
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
The invention relates to a motor-driven chain saw having an internal combustion engine for driving the saw chain of the chain saw. The engine is mounted in the housing of the chain saw and includes a cylinder and a combustion chamber formed in the cylinder. The combustion chamber is delimited by a piston and the piston drives a crankshaft via a connecting rod. The crankshaft is rotatably journalled in a crankcase. An inlet and an outlet are provided for gas exchange in the combustion chamber and the inlet is connected via an intake channel to a mixture preparation device. A stroke/bore ratio of less than 0.8 is used in order to provide an engine of reduced structural elevation which is useable in all positions. The inlet and outlet are controlled via valves having a valve drive charged with the air/fuel lubricating oil mixture supplied via the mixture preparation device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.