Manipulator

A manipulator comprising a first arm assembly having a base end portion and a free end portion, attachment means on which said base end portion is pivotally mounted by first pivotal means for pivotal movement about a first pivotal axis, first power means operatively connected to said first arm assembly to effect rotation of the latter about said first pivotal axis, a second arm assembly having a base end portion and a free end portion, second pivotal means pivotally mounting said base end portion of said second arm assembly to said free end portion of said first arm assembly for pivotal movement about a second pivotal axis, second power means, coupling means coupling said second power means to said second arm assembly to effect rotation of the latter about said second pivotal axis, holding means on said free end portion of said second arm assembly for holding an article which is to be moved by the manipulator, third pivotal means for pivotally mounting said holding means to the free end of said second arm assembly for pivotal movement about a third axis, a first coupling lever disposed parallel to the longitudinal axis of said first arm assembly and having a length equal to the length of said first arm assembly, said first coupling lever having one end pivotally mounted to said attachment means for pivotal movement about a fourth pivotal axis which is spaced from said first pivotal axis, first link means extending from said second pivotal means, said first coupling lever having its other end pivotally connected to said first link means for pivotal movement about a fifth pivotal axis spaced from said second pivotal axis, said first, second, fourth and fifth pivotal axes defining a first parallelogram, a second coupling lever disposed parallel to the axis of said second arm assembly and having a length equal to the length of said second arm assembly, said second coupling lever having one end pivotally mounted on said first link means for pivotal movement about said fifth pivotal axis, second link means extending from said third pivotal means, said second coupling lever having its other end pivotally connected to said second link means for pivotal movement about a sixth pivotal axis spaced from said third pivotal axis, a link plate means extending from said holding means and pivotally connected to said other end of second coupling lever at said sixth pivotal axis, said second, third, fifth and sixth pivotal axes defining a second parallelogram, whereby said second and fifth pivotal axes are common in both said first and second parallelograms and said holding means is maintained in a generally horizontal diposition independently of the relative pivotal positions of said first and second arm assemblies.