Electrode wire-feeding device having means for automatically adjusting the pushing force for the electrode wire

摘要

An electrode-wire feeding device in which the calibrated pushing force exerted on the electrode wire by a pair of rollers is automatically adjusted. This automatic adjustment is effected by a guide cone having an internally threaded bore which is connected to a drive motor. A housing having a hollow cylindrical externally threaded portion is adapted to be threadably engaged with the guide cone with which it is axially aligned. The housing has a pair of parallel bores the axes of which lie in a plane which is perpendicular to the feed direction of the electrode wire which is fed through the guide cone and the housing. A pair of pistons are movably mounted in the pair of bores and support a pair of rollers which are adapted to contact the electrode wire and impart a pushing and guiding force thereto. The pistons are connected to each other by a coil spring. A pair of double-armed levers are pivotally mounted on the housing. One arm of each lever is in contact with the piston and the other arm is in contact with the guide cone. The pushing and guiding force exerted by the rollers on the electrode wire is adjusted in accordance with the relative position assumed by the double- armed levers and the guide cone.