Surgical tool with mechanical advantage
First Claim
Patent Images
1. An end effector arrangement of a minimally invasive surgical instrument, the end effector arrangement comprising:
- a first end effector mounting formation having a proximal end portion and a distal end portion which includes a first distal pivot location;
a second end effector mounting formation having a proximal end portion and a distal end portion which includes a second distal pivot location, the distal end portions of the first and second end effector mounting formations being rotatably coupled together at the first and second distal pivot locations to rotate with respect to each other, each end effector mounting formation being arranged to carry an end effector element;
a first pulley rotatable about a first center of rotation and having a first force transfer location spaced from the first center of rotation, the proximal end portion of the first end effector mounting formation being rotatably coupled with the first pulley at the first force transfer location to rotate with respect to one another; and
a second pulley rotatable about a second center of rotation and having a second force transfer location spaced from the second center of rotation, the proximal end portion of the second end effector mounting formation being rotatably coupled with the second pulley at the second force transfer location to rotate with respect to one another.
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Abstract
A robotic surgical tool includes an end effector having a pair of fingers and incorporating a mechanical advantage. In specific embodiments, a pulley and cable mechanism is used to actuate the end effector by applying cable tension. The coupling between the pulleys and the fingers of the end effector takes advantage of changes in moment arms for force transfer to avoid or minimize force reduction between the applied cable tension and the resultant force at or near the distal tip of each finger. In some embodiments, the coupling of the pulleys and fingers results in a force gain, a moment gain, or both.
1051 Citations
26 Claims
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1. An end effector arrangement of a minimally invasive surgical instrument, the end effector arrangement comprising:
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a first end effector mounting formation having a proximal end portion and a distal end portion which includes a first distal pivot location;
a second end effector mounting formation having a proximal end portion and a distal end portion which includes a second distal pivot location, the distal end portions of the first and second end effector mounting formations being rotatably coupled together at the first and second distal pivot locations to rotate with respect to each other, each end effector mounting formation being arranged to carry an end effector element;
a first pulley rotatable about a first center of rotation and having a first force transfer location spaced from the first center of rotation, the proximal end portion of the first end effector mounting formation being rotatably coupled with the first pulley at the first force transfer location to rotate with respect to one another; and
a second pulley rotatable about a second center of rotation and having a second force transfer location spaced from the second center of rotation, the proximal end portion of the second end effector mounting formation being rotatably coupled with the second pulley at the second force transfer location to rotate with respect to one another. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
a first channel formation extending at least partially circumferentially around the first pulley, the first channel formation defining opposed flange formations, one of the flange formations having a diameter less than the other flange formation; and
a second channel formation extending at least partially circumferentially around the second pulley, the second channel formation defining opposed flange formations, one of the flange formations having a diameter less than the other flange formation.
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16. An end effector arrangement of a minimally invasive surgical instrument, the end effector arrangement comprising:
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a first finger including a proximal end portion having a first finger transfer aperture, a distal end portion, and a first finger pivot hole disposed between the proximal end portion and the distal end portion;
a second finger including a proximal end portion having a second finger transfer aperture, a distal end portion, and a second finger pivot hole disposed between the proximal end portion and the distal end portion, the first pivot hole and the second pivot hole being rotatably coupled for pivoting of the first and second fingers relative to one another;
a first pulley being rotatable about a first pulley pivot hole and having a first pulley transfer aperture spaced from the first pulley pivot hole, the first finger transfer aperture of the first finger being rotatably coupled with the first pulley transfer aperture for pivoting of the first finger and the first pulley relative to one another; and
a second pulley being rotatable about a second pulley pivot hole and having a second pulley transfer aperture spaced from the second pulley pivot hole, the second finger transfer aperture of the second finger being rotatably coupled with the second pulley transfer aperture for pivoting of the second finger and the second pulley relative to one another. - View Dependent Claims (17, 18, 19, 20)
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21. An end effector arrangement of a minimally invasive surgical instrument, the end effector arrangement comprising:
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a first end effector mounting formation having a proximal end portion and a distal end portion which includes a first distal pivot location;
a second end effector mounting formation having a proximal end portion and a distal end portion which includes a second distal pivot location, the distal end portions of the first and second end effector mounting formations being rotatably coupled together at the first and second distal pivot locations to rotate with respect to each other, each end effector mounting formation being arranged to carry an end effector element;
a first force transfer member being rotatable about a first center of rotation by a first applied force normal to a first applied moment arm extending from the first center of rotation, the first force transfer member being coupled with a first transfer location in the proximal end portion of the first end effector mounting formation to transfer a first transfer force to the first transfer location in response to the first applied force, the first transfer force having a first normal force component normal to a first transfer moment arm extending from the first distal pivot location to the first transfer location, the first normal force component being equal to or larger than the first applied force; and
a second force transfer member being rotatable about a second center of rotation by a second applied force normal to a second applied moment arm extending from the second center of rotation, the second force transfer member being coupled with a second transfer location in the proximal end portion of the second end effector mounting formation to transfer a second transfer force to the second transfer location in response to the second applied force, the second transfer force having a second normal force component normal to a second transfer moment arm extending from the second distal pivot location to the second transfer location, the second normal force component being equal to or larger than the second applied force. - View Dependent Claims (22, 23)
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24. An end effector arrangement of a minimally invasive surgical instrument, the end effector arrangement comprising:
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a first finger including a proximal end portion, a distal end portion, and a first finger pivot hole disposed between the proximal end portion and the distal end portion;
a second finger including a proximal end portion, a distal end portion, and a second finger pivot hole disposed between the proximal end portion and the distal end portion, the first finger pivot hole and the second finger pivot hole being rotatably coupled for pivoting of the first and second fingers relative to one another;
a first actuation member being rotatable about a first actuation member pivot hole;
first means coupled between the first finger and the first actuation member for transferring a first transfer force from the first actuation member to the first finger at a first transfer location in response to a first tangential force applied to the first actuation member, the first tangential force being normal to a radial direction extending radially from the first actuation member pivot hole, the first transfer force being normal to a first finger moment arm measured from the first finger pivot hole to the first transfer location, the first transfer force being equal to or greater than the first tangential force;
a second actuation member being rotatable about a second actuation member pivot hole; and
second means coupled between the second finger and the second actuation member for transferring a second transfer force from the second actuation member to the second finger at a second transfer location in response to a second tangential force applied to the second actuation member, the second tangential force being normal to a radial direction extending radially from the second actuation member pivot hole, the second transfer force being normal to a second finger moment arm measured from the second finger pivot hole to the second transfer location, the second transfer force being equal to or greater than the second tangential force. - View Dependent Claims (25, 26)
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Specification