Percussion apparatus, actuated by eccentric revolving masses, incorporating an electric motor

摘要

992,342. Utilizing inertia to obtain movements in machinery. G. PINAZZA. March 23, 1962 [Dec. 13, 1961], No. 11177/62. Heading F2X. A percussive tool is actuated by an eccentric rotating mass which is accelerated and retarded at each revolution and is driven by an electric motor incorporated in the tool casing, means being provided to give a reasonably uniform load on the motor. As shown in Fig. 1 a percussive drilling tool C is formed with a part 2 rotatably supporting journals 4 of eccentric masses 3 which are fast with a crank arm 6 having a roller 20 which is slidably engaged in a diametral groove 21 of a disc 22 which is fast with a shaft 23 which is rotatably mounted in the tool casing. An electric motor F is mounted in the casing and drives the shaft 23 by way of bevel gears 29, 30, a flexible shaft 32 and bevel gears 26, 25. The flexible shaft 32 reduces transmission of shocks to the motor F, and this is assisted by forming the disc 22 as a flywheel. The upper part of the tool C is fast with a piston 8 which is reciprocable in a cylinder 9 and compresses air therein during the return stroke of the tool to assist the working stroke. A lubricating oil reservoir 12 is fast with the casing and is fast with a piston 18 having a bore 16 therethrough and slidable in a bore 17 in the tool C to supply lubricant to the journals 4. In the embodiment shown in Figs. 3 and 5 an electric motor FSP1/SP is connected by spur gears to a disc 22SP1/SP which is formed as a flywheel and which drives eccentric masses 3SP1/SP in the same way as in the previous embodiment. A unidirectional rotation device 44 gives intermittent rotation of the drilling tool CSP1/SP at each stroke. The tool CSP1/SP is formed with a flange 47c which towards the limit of the downward stroke engages the flange 47 which is connected through springs 45 with a sleeve DSP1/SP which is connected by means of springs 48 to the tool casing, so that downward thrust of the tool is cushioned.