Articulated arm for holding surgical instruments

DETAILED DESCRIPTION The present invention provides an articulated arm for holding surgical instruments which comprises a plurality of elongated arm members and a plurality of rotational joints connecting said arm members end to end.
The members are pivotable about the joints and at least one of the joints is selectively lockable by positive fluid pressure.
A plurality of tubes communicate fluid pressure between two adjacent joints.
When two adjacent members are pivoted relative to one another, the plurality of tubes located on each of the members that connect two joints remains substantially stationary with respect to the arm member connecting the pair of joints, such that it is possible for the plurality of tubes to be constructed from a rigid material.
As another aspect of the present invention, the articulated arm is provided with a fluid pressure operated friction brake for locking at least one of the joints.
The friction brake includes a substantially frustoconically shaped engaging surface.
As a further aspect of the present invention, the arm is provided with a check valve that prevents inadvertent unlocking of the joints in the event that a source of fluid pressure is interrupted.
As an even further aspect of the present invention, a plurality of isolated fluid paths is provided to each joint and each of the fluid paths within each joint is isolated from the others within the joint.
These fluid paths allow fluid pressure to be communicated through the joint without the need for flexible tubing.
As a still further aspect of the present invention, the articulated arm is provided with a fluid switch located near a distal end of the arm for selectively controlling the fluid pressure within at least one of the joints, thereby unlocking the joint or joints.
All of the plurality of joints may be unlocked by operating the single fluid switch.
As a yet further aspect of the present invention, wherein an arm member is pivotable with respect to at least one of the joints by greater than 360 degrees