| 摘要 |
PCT No. PCT/EP89/00887 Sec. 371 Date Mar. 16, 1990 Sec. 102(e) Date Mar. 16, 1990 PCT Filed Jul. 27, 1989 PCT Pub. No. WO90/00951 PCT Pub. Date Feb. 8, 1990.The invention relates to a wire pistol comprising a wire feed mechanism including a wire feed pulley rotated by a DC motor and a counterpulley for biasing the wire into engagement with the feed pulley. It is an object of the invention to provide a wire pistol of this type in which, in contrast to prior-art wire pistols, no transmission shift operation or no transmission replacement is required over the entire adjustment range of wire feed rates. This object is attained according to the invention by the provision that the DC motor is adapted to have successive operating voltage pulses of variable pulse width and/or variable pulse frequency applied thereto for thus controlling the wire feed rate. This provision ensures that a sufficiently high torque for the wire feed operation is also available at very low wire feed rates, i.e. at low rotational speeds of the motor.
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