PORTABLE DRILLING MACHINE Russian patent published in 1995 - IPC

FIELD: machine-tool manufacture. SUBSTANCE: through gears 3 and 11, toothed wheels 4 and 17 rotation from electric motor 2 is transmitted to arbor 14. In this case gear-nut 13 will rotate together with the arbor due to friction between its end surface and sleeve 15. Toothed wheel 8 rotates at a speed differing from the arbor speed. When the handle is shifted towards the front end of the arbor, the shaft and additional lever turn relative to the housing and transmit rotation to the three-arm lever. At the same time the double-arm lever turns and displaces brake sleeve 18 up to the stop against the gear-nut. After the stop of the three-arm lever the double-arm lever, overcoming the spring force, continues turning until the latch tooth under the spring action enters the slot on the hub of the additional lever. The handle is released and retained against turning by the latch. Accelerated displacement of the arbor to the workpiece is effected. After the stop the arbor starts axial displacement of the gear-nut compressing the spring. The gear-nut moves aside from the lever, and the latter gets engaged with the stop. Brake sleeve 18 moves simultaneously with the gear-nut. Then, the three-arm lever through a mechanical coupling turns the latch and releases the additional lever. Then, the additional lever, three-arm lever, double-arm lever, shaft turn relative to the housing, and brake sleeve 18 is moved aside from the gear-nut until the stop rests against surface P of the L-shaped lever. In this case the gear-nut rotated by toothed wheel 8 accomplishes the working feed of the arbor. On completion, for example, of drilling accelerated withdrawal of the arbor from the workpiece occurs. At displacement of the arbor to the extreme rear position key 16 enters the annular recess of the gear-nut and gets engaged with the stop. As a result, the gear-nut starts rotating at the same speed as the arbor. Withdrawal of the arbor stops. The operating cycle is accomplished. EFFECT: improved design. 4 dwg