Microsurgical tool for robotic applications

Abstract

The disclosed technology includes improved microsurgical tools providing multiple degrees of freedom at the wrist level, including roll, pitch, and grasp DOFs, a tight articulation bending radius, low radial offset, and improved stiffness. Some implementations include an end effector platform moveable along a fixed trajectory on a fictional axle so as not to interfere with a central-axis aligned working channel; a crossed-arm mechanical linkage for articulating an end-effector platform throughout a pitch DOF with an amplified pitch angle; and a partial pulley system to articulate the arms while maximizing pulley radius to shaft diameter, and permitting a constant transmission efficiency to the arms throughout the range of articulation. In some implementations, a tool shaft outer diameter may be smaller than 3 mm; a pitch DOF range may be ±90°, a roll DOF range may be ±180°, and a grasp DOF range may be 30°.

What is claimed is: 
     
         1 . A microsurgical tool, comprising:
 an elongated body having a centerline and outer diameter at a distal end;   a platform moveably coupled to the distal end of the elongated body; and   an end effector operatively coupled to the platform and being articulable in at least three degrees of freedom, including a pitch degree of freedom up to a pitch angle of at least ±90°;   wherein a ratio of the outer diameter of the elongated body to a radial offset of the end effector to the centerline of the elongated body is at least 0.65.   
     
     
         2 . The microsurgical tool of  claim 1 , the ratio of the outer diameter to the radial offset being at least 0.83. 
     
     
         3 . The microsurgical tool of  claim 1 , further comprising a torque coil or flexible tube disposed within the elongated body to transmit torque for articulating the end effector in a roll degree of freedom. 
     
     
         4 . The microsurgical tool of  claim 1 , the end effector being infinitely articulable in a roll degree of freedom. 
     
     
         5 . The microsurgical tool of  claim 1 , the end effector being at least one of a grasper, a gripper, forceps, and scissors. 
     
     
         6 . The microsurgical tool of  claim 1 , further comprising an actuation tendon disposed within the elongated body and tensionable to actuate the end effector in a grip degree of freedom. 
     
     
         7 . The microsurgical tool of  claim 6 , further comprising:
 a torque coil disposed within the elongated body to transmit torque for articulating the end effector in a roll degree of freedom, the actuation tendon disposed within the torque coil.   
     
     
         8 . The microsurgical tool of  claim 1 , the end effector comprising a deformable grasper. 
     
     
         9 . The microsurgical tool of  claim 1 , the end effector comprising a unilateral grasper. 
     
     
         10 . The microsurgical tool of  claim 1 , the end effector comprising at least two opposing jaws articulable to open to an angle of at least about 30° relative to each other. 
     
     
         11 . A microsurgical tool, comprising:
 an elongated body having a proximal end and a distal end;   a platform operatively coupled to an end effector;   a first arm operatively coupled to a first proximal hinge and a first distal hinge, and   a second arm operatively coupled to a second proximal hinge and a second distal hinge;   the first proximal hinge and the second proximal hinge being coupled to the distal end of the elongated body and the first distal hinge and the second distal hinge being coupled to the platform; and   the first arm and the second arm being moveable to articulate the end effector in a pitch degree of freedom.   
     
     
         12 . The microsurgical tool of  claim 11 , the end effector being articulable in a pitch degree of freedom up to a pitch angle of at least about ±90°. 
     
     
         13 . The microsurgical tool of  claim 11 , wherein the first and second arms form a mechanical linkage for amplifying a pitch angle of the platform by a factor A relative to a pitch angle of the first arm. 
     
     
         14 . The microsurgical tool of  claim 11 , the first proximal hinge and the second proximal hinge being coupled to the distal end of the elongated body and the first distal hinge and the second distal hinge being coupled to the platform such that the first arm and the second arm are crossed. 
     
     
         15 . The microsurgical tool of  claim 11 , the elongated body having a centerline, the first proximal hinge being offset from the centerline. 
     
     
         16 . The microsurgical tool of  claim 11 , wherein the first and second arms form a mechanical linkage for moving the first arm with a constant transmission efficiency between the mechanical linkage and the first arm throughout a range of movement of the first arm. 
     
     
         17 . The microsurgical tool of  claim 11 , further comprising a first tendon coupled to the first arm and tensionable to move the first arm. 
     
     
         18 . The microsurgical tool of  claim 11 , the first arm coupled to a first pulley, an axis of the pulley being concentric with the first proximal hinge. 
     
     
         19 . The microsurgical tool of  claim 18 , the first pulley being a partial pulley such that a radius of the pulley not in contact with the first tendon is smaller than a radius of the pulley that is in contact with the first tendon. 
     
     
         20 . The microsurgical tool of  claim 18 , the first pulley fitting within a profile of the elongated body.