Patent ID: 6526926
Filing Date: 2003-03-04
Classification: B25C

Abstract:
A method of driving a piston of an internal combustion-engined tool having a collapsible combustion chamber (1) adjoining the piston (8), the method comprising the steps of:providing in the combustion chamber, a separation plate (18) displaceable for dividing the combustion chamber (1) into a fore-chamber section (21) and a main chamber section (22) adjoining the piston (8), the separation plate (18) having a first plurality of through-openings (38) and a second plurality of through-openings (60) spaced radially further away from a separation plate center than the through-openings (38) of the first plurality of through-openings, and an ignition device (52); expanding the combustion chamber (1) by displacing the separation plate (18) so that the fore-chamber section (21) and the main chamber section (22) are formed, with the ignition device (52) being located, upon expansion of the combustion chamber (1), in the fore-chamber section (21); filling the fore-chamber section (21) and the main chamber section (22) with combustible gas mixture; and igniting the ignition device (52), whereby the combustible gas mixture in the fore-chamber section (21) is ignited, with formation of gas jets penetrating through the first plurality of through-openings (38) of the separation plate (18) into the main chamber section (22), and the combustion gas mixture in the main chamber section (22) is combusted, providing pressure for driving the piston (8), with a portion of the combusting gas mixture flowing back into the fore-chamber section (21) through the second plurality of through-openings (60) of the separation plate (18), igniting a not-yet combusting gas mixture in a radially outer region of the fore-chamber section (21).