Flexible arm

Claim 1

In a flexible arm composed of a plurality of units disposed by being stacked in series and an actuating device connected thereto for curving the respective units, each of the units comprising: (a) one disc having projectingly-curved contact surfaces defined on both sides thereof; (b) one support plate provided with a central hole defined coaxially with the axial center thereof to which said disc is fixed and a plurality of plate fitting surfaces alternately defined on both sides at the peripheral portion thereof with their phases shifted 90° about the axial center, each pair of the fitting surfaces being composed of those symmetrical with respect to the axial center; (c) two torsion plates each provided with a hole defined at the center thereof for loosely accommodating said disc and a plurality of plate fitting surfaces alternately defined on both sides at the peripheral portion thereof with their phases shifted 90° about the axial center thereof, the fitting surfaces defined on the same surface of said torsion plate in an axial direction being fixed to each pair of the plate fitting surfaces on both sides of said support plate; and (d) one intermediate plate provided with a central hole defined coaxially with the axial center thereof with which said disc is loosely engaged and plate fitting surfaces which are defined on both sides in the axial direction at the peripheral portion thereof and have their phases shifted 180° from one another so that they are symmetrical with respect to the axial center, said plate fitting surfaces being fixed to a pair of the fitting surfaces on a side, which is not fixed to the plate fitting surfaces of said support plate, of one of said two torsion plates, whereby the respective discs of said respective units are brought into contact with each other and the torsion plate and the intermediate plate of each unit are connected by the respective fitting surfaces.