Patent ID: 7795832

Claim:
A robot hand including a plurality of finger mechanisms corresponding to a plurality of human fingers, respectively, each of said finger mechanisms being constituted by a plurality of phalange sections including a distal phalange section and a middle phalange section adjacent to the distal phalange section, said robot hand comprising: a fingertip rotating mechanism that causes the distal phalange section to rotate relative to the middle phalange section in two directions comprising an inward direction and an outward direction within a predetermined angular range, from a state where the distal phalange section is arranged in a straight line with the middle phalange section, and that includes at a connecting portion between the distal phalange section and the middle phalange section a single degree of freedom joint for allowing bending or stretching and also includes a driving mechanism that causes the joint to make a rotating motion within the predetermined angular range; and a rotation driving mechanism that causes a first finger mechanism corresponding to a human thumb among said finger mechanisms to rotate by a predetermined angle about a center line extending in a direction where the phalange sections constituting said first finger mechanism are arranged so that said first finger mechanism is fully facing the other finger mechanism, wherein the joint and the driving mechanism are configured so that the distal phalange section can be rotated relative to the middle phalange section in the two directions, namely, the inward direction and the outward direction within the predetermined angular range from the state where the distal phalange section is arranged in a straight line with the middle phalange section, the driving mechanism included in the fingertip rotating mechanism comprises a motor for driving the joint and a speed reducer, the motor for driving the joint being included in the middle phalange section and generating a driving force for rotating the joint, the speed reducer reducing a speed of the motor and transmitting the reduced speed to the joint, and the speed reducer comprises: a first pinion gear fixed to an output shaft of the motor, a first spur gear that is fixed to a rotary shaft rotatably supported by the middle phalange section and meshes with the first pinion gear, a second pinion gear fixed to the rotary shaft, and a second spur gear that is fixed to the distal phalange section so that a rotation center of the joint becomes a rotation center of the second spur gear and meshes with the second pinion gear.