Pulley

About: Pulley is a research topic. Over the lifetime, 51636 publications have been published within this topic receiving 178220 citations. The topic is also known as: drum & block.

Surgical instruments with tensioning arrangements for cable driven articulation systems

Abstract: A surgical instrument comprising an elongate shaft assembly that defines a shaft axis. A surgical end effector is pivotally coupled to the elongate shaft assembly for selective articulation relative to the elongate shaft assembly about an articulation axis that is transverse to the shaft axis. An articulation cable is coupled to the surgical end effector at a point of attachment and is journaled on a proximal pulley that is supported on the elongate shaft assembly. The proximal pulley defines a proximal pulley axis that is located a tension distance from the point of attachment. An articulation driver is coupled to the articulation cable for selectively causing the articulation cable to rotate about the proximal pulley in first and second articulation directions. An adjustable tensioning assembly interfaces with the proximal pulley to selectively adjust the tensioning distance.

Surgical tool with mechanical advantage

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.

Improved actuating handle with pulley system for providing mechanical advantage to a surgical working element

Abstract: A medical device has a body, an actuating member mounted to move relative to the body, a working element, and an elongated force-transmitting member capable of transmitting actuating force between the actuating member and the working element. The force-transmitting member includes a flexible cable portion, the force-transmitting member is attached, on one side of the cable portion, to the body and associated in a driving relationship on the opposite side of the cable portion with the working element. According to the invention the actuating member includes a pulley surface bodily movable therewith, the cable portion is trained about the pulley surface such that movement of the actuating member a given distance, relative to the body, causes the working element to move a substantially greater distance than the given distance. Another aspect of the invention is a medical snare with the above features.

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°.

Compact cable transmission with cable differential

Abstract: A pretensioned cable transmits power along a first support member (link) from a rotary actuator to a rotating output joint, typically an output pulley fixed to a second link arm but rotatable in a coupling between the first and second links. A reducer, typically two sets of coupled idler pulleys of different diameter, is mounted at a point removed from the actuator, and preferably as close as possible to the output joint. An axially split spool mounted on the actuator output wraps the outgoing and returning cable sections on different halves of the spool in opposite directions to provide pretensioning of the cable in the entire cable circuit at one point. To form a differential, a pretensioned cable carried on paired pulleys having smooth outer surfaces parallel to the axis of rotation couples the pulleys. The pulleys have axes of rotation that can intersect and their cable carrying surfaces are closely spaced, preferably by less than half the width of the cable. The outer surfaces can be stepped to accommodate two or more cables for bi-directional operation, or to create a conventional differential with a spider. The links and pulleys of the transmission are long and narrow. This high aspect ratio provides a compact configuration that is conducive to whole arm manipulations where any exterior surface of the links can engage an object. A low inertia, low friction brushless D.C. motor operating under the control of a pulse width modulated controller responsive to the current drawn by the motor, in combination with the cable transmission of this invention, provide excellent force control.