Geared grip actuation for medical instruments
An actuation mechanism for a medical instrument includes a pinion and a face gear that move a push-pull element. The pinion has a mounting that permits rotation of the pinion by an external control system such as a robot. The face gear meshes with the pinion. The push-pull element may have a proximal end coupled to the face gear and a distal end coupled to a tool at a distal end of an instrument shaft. A manipulator coupled for manual rotation of the actuation mechanism may include a slip clutch to prevent manual application of excessive force to the actuation mechanism.
1. A medical system comprising:
a rotatable pinion;
a face gear meshed with the pinion;
a medical tool; and
a push-pull element comprising a proximal end and a distal end, the proximal end being coupled to the face gear, and the distal end being coupled to the medical tool.
2. The medical system of claim 1 , wherein a rotation axis of the face gear and a rotation axis of the pinion do not intersect.
3. The medical system of claim 1 , further comprising: to an input spindle having an engagement feature shaped to engage a teleoperated actuator; and
the pinion is coupled to the input spindle.
4. The medical system of claim 1 , further comprising a slip clutch coupling a manipulator for rotation of the pinion.
5. The medical system of claim 1 , wherein the pinion is selected from a group consisting of a spur gear and a helical gear.
6. The medical system of claim 1 , wherein the face gear comprises a sector gear.
7. The medical system of claim 1 , wherein:
the face gear comprises a first plate, a second plate, and a shaft perpendicular to the first plate and the second plate; and
the first plate and the second plate are separated by a gap through which an actuation mechanism accesses an instrument shaft of the medical tool.
8. The medical system of claim 1 , wherein the face gear comprises a first plate, a second plate, and a connector coupled between the first plate and the second plate, the connector connecting the push-pull element to the face gear.
9. The medical system of claim 1 , further comprising a bearing contacting the face gear on a side opposite to where the pinion meshes with the face gear.
10. The medical system of claim 1 , wherein the medical tool comprises a grip mechanism that is actuated by pushing and pulling the push-pull element.
11. The medical system of claim 1 , wherein the pinion comprises a helical gear having a helix angle that accommodates an offset between an axis of the pinion and an axis of the face gear.
12. The medical system of claim 1 , wherein the push-pull element couples to the face gear at a first radius from a rotation axis of the face gear, and the pinion meshes with the face gear at a second radius from the rotation axis of the face gear, the second radius differing from the first radius.
13. A medical instrument comprising:
a tool;
an actuation mechanism coupled to the tool and having an engagement feature shaped to engage an actuator, wherein rotation of the engagement feature actuates a portion of the tool; and
a manipulator coupled to the actuation mechanism and including a slip clutch, wherein rotation of the manipulator actuates the portion of the tool.
14. The medical instrument of claim 13 , wherein the slip clutch comprises:
a plunger; and
a spring system that pushes the plunger into a notch in an axle structure of the actuation mechanism.
15. The medical instrument of claim 14 , wherein:
the manipulator comprises a knob; and
the spring system comprises a flexure formed in the knob and positioned to push the plunger into the notch.
16. The medical instrument of claim 15 , wherein:
the manipulator comprises a knob; and
the spring system comprises a spring disposed in a pocket in the knob and positioned to push the plunger into the notch.
17. The medical instrument of claim 14 , wherein the notch is disposed on a cylindrical surface of the axle structure.
18. The medical instrument of claim 14 , wherein the notch is disposed in a plate that extends around an axle of the axle structure.
19. The medical instrument of claim 13 , wherein:
the manipulator comprises a knob; and
the slip clutch comprises a clip engaged in the knob and providing a friction fit to an axle in the actuation mechanism.
20. The medical instrument of claim 13 , wherein:
the actuator is a drive motor in a robotic system; and
the manipulator comprises a manually operated knob.