| 摘要 |
The invention aims to improve the power/weight ratio of a two-stroke engine employed as the prime mover in a drilling and chiselling hammer 1 (sometimes also known as a percussion tool) of the kind in which percussion impacts are transmitted to a tool holder 3 of the tool by way of a percussion piston 9 which is reciprocated by the engine, thereby to enable the tool to be lighter, so that it can more readily be manipulated in the case of a hand-held tool. To achieve this improved efficiency, crank 7 of the percussion piston 9 is accommodated in a chamber 1a into which air is drawn by way of a non- return valve 11 upon movement of the piston 9 towards the top dead-centre position and from which air is displaced, under compression, through a pipeline 13 to an entry slot 1e of the cylinder 1c of the engine. <IMAGE> |
