Wrist mechanism for robotic manipulations

A wrist mechanism suitable for robotic manipulators comprising first actuator means for rotating a first yoke about a first axis (W1), a first cross shaft, one shaft of which is mounted for rotation in bearings carried by arms of said first yoke, the other shaft of which has its ends mounted in bearings carried by a pair of spaced parallel side plates, second actuator means for pivoting said first cross shaft in said bearings about a second axis (W2), a second cross shaft having one shaft mounted in bearings carried by said side plates, the other shaft of which pivotally carries a second yoke adapted to carry an end effector, third actuator means for causing rotation of said wrist mechanism about a third axis (W3) coincident with the axis of said other shaft of said first cross shaft, cross members rigidly interconnecting said side plates, and gear means for transferring motion between said first cross shaft and said second cross shaft and for transmitting drive between said first yoke and said second yoke, whereby said third actuator means causes simultaneous rotation about said third axis and about an axis parallel to the axis of said second cross shaft said side plates, said cross members, said bearings and said gears being constructed and adjusted to provide high rigidity in said wrist mechanism, said side plates and said cross members being of such a configuration to allow pivotal movements of the end effector in excess of 180.degree. about said second axis and at least 180.degree. about said third axis, said first actuator being constructed to allow rotation in excess of 200.degree. about said first axis.