| 摘要 |
1275216 Percussive tools G A BERGMAN 6 July 1970 [29 May 1970] 32545/70 Heading B4C A percussive tool comprises an I.C. engine which via a connecting rod 32 imparts reciprocating motion to a cylinder 22, and an impact piston 26 the head of which is located within the cylinder 22. Air is received in and expelled from spaces 24, 25 during reciprocation of the cylinder, and the air in those spaces, when the head of piston 26 has moved upwardly or downwardly past ports 42 and 44 respectively, cushions the piston 26. During the compression stroke of piston 12 air is sucked into housing 34 via an intake 36 and mixed with a fuel-oil mixture entering through nozzle 38. Air admitted to space 48 via a one way valve 60 during a suction stroke of cylinder 22 is, during the compression stroke of the piston 12, forced via one-way valve 56 and passage 52 into chamber 54 and oil from the crank housing deposited on the inner wall of the cylinder 20 is carried by that air to lubricate the tool and possibly a rotating mechanism. Upon the exhaust stroke of piston 12 the exhaust port 64 is opened and the fuel-oilair mixture passes via passage 62 into the cylinder space above piston 12, and the cylinder 22 performs its suction stroke. |
