Manipulation arm mechanism for an industrial robot

Abstract

A manipulation arm mechanism for an industrial robot is provided with a pivotable arm in which a first shaft driven by a drive motor is carried for rotation about an axis extending in a longitudinal direction of the arm. The first shaft has secured to its front end a rear casing, on which a front casing is carried for rotation about an oblique axis slanted relative to the first shaft axis. A head mounting shaft capable of attaching thereto a working head such as, for example, a handling gripper is carried in the front casing to be rotable about an axis which extends in axial alignment with the first shaft axis only when the front casing is at a predetermined angular position about the oblique axis. Second and third shafts driven by respective drive motors pass through the first shaft and present into the rear casing their front ends, to which the front casing and the head mounting shaft are drivingly connected through gear trains respectively. Each axis of the second and third shafts is radially offset from the first shaft axis. This offset arrangement ensures a relatively large space reserved just behind the front casing, so that the working range of the working head about the oblique shaft can be broadened.