Patent ID: 7100491

Claim:
A fluid-powered mechanical actuator having a proximal end and a distal end and comprising: an elongated framework comprising a plurality of structural elements hingedly connected serially in end-to-end linked relationship to form a variable angle therebetween, each linked pair of elements comprising: a first element and a second element; a hinge that hingedly connects an end of the first element to an end of the second element, thereby allowing one degree of freedom for rotational movement about a hinge axis for the first element and the second element relative to each other; a bias in the direction of minimizing the angle between the first element and the second element; a flexible elongated chamber that extends along a portion of the first element's length, across the hinge, and along a portion of the second element's length; and a portion of the first element that holds the chamber and a portion of the second element that holds the chamber such that the chamber, and the first and second elements, are constrained to move together; wherein the chamber comprises: a flexible but non-expansible wall that is substantially non-permeable to a working fluid; an enclosed space within the wall; and a fluid conduit connected to the enclosed space for communicating a controlled pressure to the working fluid contained in the enclosed space, such that the chamber will tend to straighten in response to a pressurized working fluid therein, thereby exerting a force always in opposition to that of the bias.