Patent ID: 8876858

Claim:
A surgical instrument comprising: a mechanical signal generator in the form of an instrument handle or a robotic interface, an instrument shaft having a distal end and a proximal end at which the signal generator is connected, an instrument head, pivotally linked to the distal end of the instrument shaft via a hinge, and comprising an effector rotatably supported in said instrument head around a longitudinal axis of the instrument shaft, said effector holding at least one surgical tool in the form of a forceps or a scissors, and a mechanical transmission system transmitting and/or converting mechanical operation signals from said signal generator to said instrument head, said mechanical transmission system comprising: a pushing tube shaft shiftably supported within said instrument shaft to transmit pivoting signals to said instrument head via a lever, a rotating tube shaft rotatably supported within said pushing tube shaft to transmit rotating signals to said effector via a bending flexible as well as torsional rigid, hollow spindle, and an actuating rod shiftably supported within said rotating tube shaft to transmit actuating signals from said signal generator to said surgical tool via a Bowden cable system comprising at least one push-/pull cable being guided within a resin tube which is inserted into the bending flexible as well as torsional rigid, hollow spindle, said bending flexible as well as torsional rigid, hollow spindle being arranged to bypass said hinge such that a first portion of said spindle is located between said mechanical signal generator and a hinge axis of said hinge, and a second portion of said spindle is located between said hinge axis and said instrument head, said spindle directly connecting said effector with said rotatable tube shaft, wherein said bending flexible as well as torsional rigid, hollow spindle has a spiral spring with coils in an axially middle portion thereof and a connecting element in form of a bar on each axial end portion thereof, said two connecting elements being integral with the spiral spring to form one piece, one bar of said bending flexible as well as torsional rigid, hollow spindle being connected to the rotating tube shaft and another bar of said bending flexible as well as torsional rigid, hollow spindle being connected to the effector, wherein a pitch of said spiral spring is configured such that: in an unbent position, the coils are spaced apart from each other, and in a maximally bent position in accordance with a maximum pivoting position of the instrument head, the coils remain spaced apart from each other, and further wherein said bending flexible as well as torsional rigid, hollow spindle is serially inserted into the mechanical transmission system such that torque generated by the signal generator is transmitted to the instrument head via said spiral spring when said rotating tube shaft rotates within said instrument shaft, and said spiral spring additionally bends when said instrument head pivots about said hinge axis.