| 摘要 |
<p>1534604 Silenced fastener driver tool HILTI AG 6 Aug 1976 [8 Sept 1975] 32857/76 Heading B4C A silenced explosive powered fastener driver tool comprises a piston 8 which is axially displaceable in a combustion chamber 2c between a rearward, firing position and a forward position, one or more exhaust apertures 2b communicating the combustion chamber with a first noise muffling chamber 10a which in turn communicates with at least one further noise muffling chamber 10b via one or more apertures 11a in a diaphragm 11, the last chamber (10c, as shown) having an outlet 13a for the exhaust gases, the volume of the first muffling chamber 10a being 3 to 10 times the volume swept by piston 8 between its rearward firing position and the position shown at which it begins to expose aperture 2b. As shown 3 muffling chambers 10a, 10b and 10c are separated by diaphragms 11, 12 whose apertures 11a, 12a and outlet aperture 13a are staggered relative to adjacent apertures. Preferably the total area of aperture(s) 11a in the first diaphragm is equal to or less than the total area of the apertures in the or each succeeding diaphragm, and the area of outlet aperture 13a is 2 to 10 times the area of aperture(s) 11a. Safety mechanism.-Spring 3 urges barrel 2 forwards, so that the tool has to be pressed against workpiece 4 to bring cartridge 6 into the firing position.</p> |
