Abstract: A distal tip of an endoscopic device and a cylindrical cap is disclosed. The distal tip comprises a pattern of alternating grooves and lands on its outer surface. The cylindrical cap is configured to fit tightly over the lands, thereby changing the grooves into closed channels through which liquid or gas can flow.

Abstract: A disposable section of an endoscope handle, an endoscope handle, and an endoscope are provided. The disposable section of an endoscope handle includes: a housing provided with a connecting portion that is detachably connected to a reusable section of the handle; an inserting unit including a proximal end located at a distal end of the housing; and a first transmission assembly including: a first traction wire, a second traction wire, and a first connecting element, where the first traction wire and the second traction wire are located in the inserting unit; proximal ends of the first traction wire and the second traction wire are connected to the first connecting element; a proximal end surface of the housing forms a linear movement path that is orthogonal to an axial direction of the proximal end surface; and the first connecting element is movable along the linear movement path.

Abstract: The present invention relates to an endoscope including a connector configured to be coupled to an external device and receive power from the external device, wherein the connector includes: a power transmission cable configured to transmit power to a bendable section; a power receiving part comprising a first slider configured to move in a first direction by receiving power from the external device and a second slider configured to move in a second direction by receiving power from the external device like the first slider; and a power transmission part configured to receive power from the power receiving part and transmit the same to the power transmission cable.

Abstract: The present invention relates an endoscope, including: a bendable section configured to be inserted into a subject's body to collect image information; and a power transmission means configured to transmit power provided by the power source to the bendable section, wherein the power transmission means comprises a power-transmitting mechanical cord and a friction control part configured to promote or restrain a movement of the mechanical cord.

Abstract: A medical device includes a handle including an axle, a device shaft extending from the handle to a distal end, and a control device. The control device is coupled to the handle, and the control device includes a knob. The knob is rotatable relative to the handle. The control device also includes a control shaft extending from the knob, at least one spring clutch including two legs, and a spool. The spool is rotatable relative to the axle. The control device also includes one or more wires coupled to the spool. Rotation of the knob is configured to rotate the control shaft, causing the at least one spring clutch to loosen, the spool to rotate, and the one or more wires to move.

Abstract: Provided is an endoscope device capable of enhancing mechanical strength and durability against various operations and attachment to and detachment from a hanger in the endoscope device in which an endoscope can be suspended on the hanger. This endoscope device includes: an insertion portion; an operation unit that has a joint section configured to be suspendable from a hanger and is connected to the hanger through the joint section; a treatment tool channel that is arranged inside the joint section and the operation unit and allows passage of a treatment tool; a plate fixed to the operation unit; and a frame that is provided inside the joint section, includes a plurality of partition structural members coupled to each other and having a longitudinal direction along an arrangement direction of the treatment tool channel, and is fixed to the plate.

Abstract: An endoscope having an operating handle including a handle housing arranged at a proximal end and an insertion tube extending from the handle towards a distal end of the endoscope and terminating in a steerable tip part at the distal end of the endoscope, the endoscope further including a control mechanism with a Bowden cable having an outer guide tube having a first length between a proximal end and a distal end of the outer guide tube and an inner pull-wire having a second length between a proximal end and a distal end of the inner pull-wire, the second length being longer than the first length, the proximal end of the outer guide tube is affixed to the operating handle by an adhesive.

Abstract: An endoscope system includes an endoscope, and an insertion auxiliary tool into which the endoscope is inserted. A flexible portion of the insertion section of the endoscope includes, from a distal end side toward a proximal end side, a low flexural rigidity portion, and a flexural rigidity varying portion in which a flexural rigidity increases from the distal end side toward the proximal end side. When at least a part of the flexible portion projects from a distal end opening of the tube body, a position of the proximal end of the low flexural rigidity portion is positioned closer to a proximal end of the insertion auxiliary tool than the distal end opening of the tube body from the proximal end of the insertion auxiliary tool.

Abstract: The present disclosure relates generally to the field of medical devices. In particular, the present disclosure relates to medical devices and systems with control knobs designed for improved usability and ergonomics. For example, the control knobs of the present disclosure may include surface features for improved gripping, surface features for improved perception of medical device orientation within a patient and/or knobs dimensioned for improved thumb reach and reduced torque.

Abstract: An endoscope head and endoscope including such endoscope head includes a camera, a housing element made from transparent material which surrounds the camera at least laterally and at least in portions and extends to the distal end of the endoscope head, and including at least one illumination unit which is arranged laterally from the camera and/or proximally from the camera.

Abstract: A surgical camera system comprising: a camera head including a housing; an image sensor within the housing; and the housing including a liquid lens therein for focusing an image received in the housing prior to transmission of the image to the image sensor, and a fixed solid lens adjacent the liquid lens.

Abstract: An endoscope used for insertion into a patient's body is disclosed herein. The endoscope can comprise an outer sleeve defining a longitudinal axis. The outer sleeve can comprise a first deflecting segment and a second deflecting segment at a distal portion of the outer sleeve and one or more slots at the distal portion. The endoscope can further comprise an inner sleeve positioned within the outer sleeve and comprising a working channel. The inner sleeve can comprise one or more extending elements at a distal portion of the inner sleeve, the one or more extending elements being coupled to the first deflecting segment of the outer sleeve. The endoscope can further comprise a tool advanceable through the working channel, wherein advancement of the tool transitions the distal portion of the outer sleeve between a straight profile and a deflected profile.

Abstract: A catheter includes a handle and an elongate member extending from the handle. The catheter may also include steering system coupled to the handle. The steering system may be configured to deflect at least a portion of the elongate member in at least one direction. The catheter may also include a locking mechanism configured to lock the portion of the elongate member in a deflected configuration, and a lever coupled to the handle. The lever may be configured to move from a first position to a second position to engage the locking mechanism. The lever may also be configured to be separably retained at least at one of the first position or the second position to prevent movement therebetween.

Abstract: A disposable section of an endoscope handle, an endoscope handle, and an endoscope are provided, including a housing which includes a proximal end provided with a connecting portion, where the connecting portion is configured to be detachably connected to a reusable section of the handle; and a first transmission assembly including a first traction wire, a second traction wire, and a first connecting portion, where a proximal end surface of the housing forms a first curved movement path; the first curved movement path is orthogonal to an axial direction of the proximal end surface and located at a periphery of the proximal end surface of the housing; and the first connecting portion is movable along the first curved movement path.

Abstract: Systems and methods of assembling a wrist assembly are provided. The wrist assembly includes a tension member, a first link, and a second link. The second link includes an assembly path, a guide path, and a retention pocket. A first end portion of the tension member is inserted through the assembly path within the second link. The tension member is configured to be rotated to transition the first tension member portion from the assembly path to be within the guide path. The retention member is retained within the retention pocket on a condition that the first tension member portion is rotated to be within the guide path such that movement of the tension member relative to the second link is limited. Movement of the first tension member portion within the second guide path urges the second link to rotate relative to the first link.

Abstract: Disclosed herein is an endoscope system and a handle for a medical device that allows for rotation of the device when a locking member is disengaged by an operator, but does not allow for rotation when the locking member is engaged. Such a handle allows for an operator to maintain the position of an endoscope even when the operator removes his or her hand from the controls of the scope.

Abstract: A robotic manipulator includes an arm including at least one joint driven by a transmission comprising an output, an isolation mechanism coupled to the output of the transmission, and a force/torque sensor coupled to the isolation mechanism. The force/torque sensor includes a body, which includes a stationary part and a movable part coupled to and being movable relative to the stationary part. The force/torque sensor also includes one or more sensing elements configured to sense forces and torques applied to the movable part. The isolation mechanism is configured to deform in response to forces induced by the transmission to mechanically isolate the force/torque sensor from forces induced by the transmission.

Abstract: An endoscope includes: a coil spring which is helically wound around an outer periphery of a treatment instrument channel disposed in an insertion section, the coil spring including a distal end which is fixed to the insertion section on a distal end portion side with respect to a bending portion; and a slide member disposed on a proximal end side of the coil spring, the slide member provided for applying an operation force for deforming the coil spring so as to increase a bending strength of at least a portion of the coil spring corresponding to the inside of the bending portion.

Abstract: A method of assembly of an endoscope control system including: holding a first control wheel unit in a position; moving a second control wheel unit in an assembly direction to position the second control wheel unit on the first control wheel unit; moving a housing frame in the assembly direction to position the housing frame on the second control wheel unit; moving a second shaft unit in the assembly direction so that a second shaft is positioned to extend through the connection hole of the housing frame and snaps into engagement with the second control wheel unit; and moving a first shaft unit in the assembly direction so that a first shaft is positioned through the second shaft and snaps into engagement with the first control wheel unit.

Abstract: An endoscope includes an endoscope operation unit; an insertion observation unit extending forward from the endoscope operation unit in a longitudinal direction of the endoscope; a coupling portion between the endoscope operation unit and the insertion observation unit; and an elastic body that covers at least a coupling portion.

Abstract: An endoscope control system for performing a bending operation in a disposable insertion endoscope, the endoscope control system including a control wheel connected to a wire drum for connection to a steering wire of the endoscope, whereby rotation of the control wheel controls the bending operation, and a multi-disc brake including a stack of at least three brake discs, wherein activation of the multi-disc brake changes the multi-disc brake from a released state to a braking state, a brake torque generated by the multi-disc brake in the braking state braking rotation of the control wheel, the brake torque in the released state being at least partially released.

Abstract: Articulating medical instruments and corresponding techniques can be utilized using a robotically enabled medical system. In a surgical method, a clinician can insert a distal end of a medical instrument into a treatment area of a patient. Once inserted, a first bending section of the medical instrument can be articulated by driving one or more motors of an articulation handle that is positioned at a proximal end of the elongated shaft.

Abstract: The specification describes endoscopes that enable varying stiffness of an insertion portion in an endoscope assembly. In one example, an actuator operates either a spring or a flexible tube to vary stiffness of the insertion portion. In alternative examples, an elliptical wheel arrangement or screw mechanism provides a means to increase stiffness of the insertion portion of an endoscope assembly. In further examples, fluid and gas may be used inside the insertion portion to vary stiffness by varying pressure of the fluid/gas.

Abstract: An endoscope includes: an insertion section; an operation section; a bending portion; a longitudinal member for maintaining a constant distance from the operation section to a distal end portion of the insertion section along a longitudinal axis of the insertion section; and a flexible tube portion provided in a movable manner with respect to the operation section and the longitudinal member in a longitudinal axis direction, and making the bending portion extend and contract with movement of the flexible tube portion with respect to the operation section in the longitudinal axis direction.

Abstract: A medical tool includes a rotatable hollow tube and one or more electrical wires. The rotatable hollow tube is defining a working channel therein for insertion of a medical instrument into a cavity of a patient body. The one or more electrical wires traverse the working channel for exchanging electrical signals with one or more electronic devices located at a distal end of the rotatable hollow tube. The working channel has a non-circular cross section for passing both the medical instrument and the one or more electrical wires, and for allowing rotation of the rotatable hollow tube relative to the medical instrument located inside the working channel in the presence of the one or more electrical wires.

Abstract: A probe includes an articulating member with at least two vertebrae elements sequentially arranged along a long axis of the elongate ultrasound imaging probe. The articulating member includes pivots located between the at least two vertebrae elements. The pivots are disposed off-center relative to the at least two vertebrae elements. The pivots are spatially oriented to provide a pivot point for a different articulation direction of a vertebra element. The probe further includes a plurality of guides, including at least one guide for each of the respective different pivot directions. The probe further includes an actuator with a set of controls, each control configured to actuate a different pair of the plurality of guides for controlling opposing articulation directions, wherein the actuator reduces stress induced on at least one of a pushed guide or a non-activated guide, wherein the stress is induced in response to the actuator pulling a guide.

Abstract: An endoscope camera head 6 includes a first and a second members 8, 9 that are relatively rotatable about a first axis Ax1. The first member 8 has a first rotation-sliding surface 84 that extends in an annular shape about the first axis Ax1 as its center. The second member 9 has a second rotation-sliding surface 93 that engages with the first rotation-sliding surface 84 in a state in which movement to a direction of the first axis Ax1 relative to the first member 8 is restricted, and that rotation-slides relative to the first rotation-sliding surface 84 about the first axis Ax1. The second rotation-sliding surface 93 abuts only on a part of the first rotation-sliding surface 84, to expose a part of the first rotation-sliding surface 84 outside.

Abstract: Provided are a handle for an endoscope comprising an endoscope housing and a lens tube and wherein on the endoscope housing at least one operating element for changing a setting of the endoscope is provided, wherein the handle comprises a receiving section for receiving and retaining the endoscope and a grip section connected with the receiving section for retaining the endoscope, in which the handle further comprises at least one manipulator for operating the operating element when the handle is disposed on the endoscope, wherein the manipulator is movable relative to the receiving section and relative to the grip section, an endoscope with such a handle and a method for disposing such a handle on an endoscope.

Abstract: The present invention relates to an intubation system comprising insertion unit to be connected to a bending section of a medical instrument comprising an inner elongated shaft structure being capable of torque transmission around its length axis and an outer elongated shaft structure surrounding the inner elongated shaft structure and having a continuous outer surface, and an orientation controller being attached to the inner elongated shaft, such that when the orientation controller rotates, the bending section turns around itself.

Abstract: A detachable endoscope includes an insertion unit including an illuminating and image pickup unit, an operation unit configured to bendingly operate a front end of the insertion unit, and a detachable unit configured to detachably couple the insertion unit and the operation unit to each other, wherein the detachable unit comprises: a first detachable module disposed at the insertion unit in such a manner as to be connected to respective one ends of first and second operating wire and third and fourth operating wires juxtaposedly arranged in the insertion unit; and a second detachable module disposed at the operation unit in such a manner as to be connected to respective both ends of upper and lower chains wound around upper and lower sprockets of the operation unit.

Abstract: An endoscope system includes an endoscope, and an insertion auxiliary tool into which the endoscope is inserted. A flexible portion of the insertion section of the endoscope includes, from a distal end side toward a proximal end side, a low flexural rigidity portion, a flexural rigidity varying portion in which a flexural rigidity increases from the distal end side toward the proximal end side, and a high flexural rigidity portion with flexural rigidity higher than that in the low flexural rigidity portion. When at least a part of the flexible portion projects from a distal end opening of the tube body, a position of the proximal end of the low flexural rigidity portion is positioned closer to a proximal end of the insertion auxiliary tool than the distal end opening of the tube body from the proximal end of the insertion auxiliary tool.

Abstract: A handle for an endoscope has a handle housing, an operating member (7) accommodated in said handle, at least one pull wire (17) attached to said operating member (7), and at least one guide tube (16) surrounding and supporting said at least one pull wire (17). The guide tube (16) is fixed with respect to said handle housing at at least a first location. A direction guide (24) adapted for directing the free end of the pull wire (17) in a desired direction during assembly of the endoscope is provided at said first location.

Abstract: A medical system includes a medical instrument, at least one actuator, and a controller. The medical instrument defines a central axis and includes a steerable tip. The controller is configured to command the at least one actuator to cause active steering control of the medical instrument according to an insertion control mode after movement of the medical instrument is detected and exceeds a first threshold value in an insertion direction and to deactivate the at least one actuator to cause the steerable tip of the medical instrument to move freely, without the active steering control, in reaction to forces exerted against the medical instrument by a wall of the anatomic passageway after axial movement of the medical instrument is detected by the medical system and exceeds a second threshold value in a retraction direction. At least one of the first or second threshold values comprises a velocity threshold value.

Abstract: A surgical instrument comprising a handle assembly, an elongated shaft, an end effector, a rotation mechanism, and an articulation mechanism is disclosed. The rotation mechanism is disposed in mechanical cooperation with the handle assembly and effects rotation of the end effector about the second longitudinal axis. The articulation mechanism is disposed in mechanical cooperation with the handle assembly and effects movement of the end effector from a first position where the first longitudinal axis is substantially aligned with the second longitudinal axis to a second position where the second longitudinal axis is displaced from the first longitudinal axis. The articulation mechanism comprises a first articulation control disposed in mechanical cooperation with the handle assembly, a first cable and a second cable. Actuation of the first articulation control in a first direction causes the first cable to move distally and causes the second cable to move proximally.

Abstract: The present disclosure relates generally to the field of medical devices. In particular, the present disclosure relates to medical devices and systems with control knobs designed for improved usability and ergonomics. For example, the control knobs of the present disclosure may include surface features for improved gripping, surface features for improved perception of medical device orientation within a patient and/or knobs dimensioned for improved thumb reach and reduced torque.

Abstract: A transluminal sheath is advanced into a femoral vein of a subject, through an inferior vena cava of the subject, into a right atrium of a heart of the subject, and transseptally into a left atrium of the heart. A surrounding-sheath is advanced out of a distal end of the transluminal sheath, into the left atrium, and toward a commissure of a mitral valve of the heart. A commissural helix is implanted at the commissure by advancing the commissural helix out of the surrounding-sheath and through the commissure into a left ventricle of the heart, such that the commissural helix wraps around at least some chordae tendineae at the commissure and facilitates sealing of the commissure. Subsequently to the implantation of the commissural helix, the surrounding-sheath is extracted from the heart. Other embodiments are also described.

Abstract: The disclosed technology is directed to an endoscope having respective first and second operations, a movable member, respective support and friction members, a cam member and a click mechanism all of which are engaged with one another to operate the endoscope during an operation. First and second operation members are disposed in the endoscope and are rotationally operated around a predetermined axis to carry out operation of the endoscope. A movable member is disposed inside the first operation member and is movable between a first position and a second position. A cam member having a cam surface that is made with an inclination with respect to the predetermined axis and abuts against part of the movable member. A click mechanism holds the cam member at the first position or the second position.

Abstract: An endoscope includes a flexible member and a variable stiffness apparatus installed in the flexible member. The variable stiffness apparatus includes a first longitudinal member and a second longitudinal member movable along the first longitudinal member. The first longitudinal member includes a first high bending stiffness portion and a first low bending stiffness portion. The second longitudinal member includes a second high bending stiffness portion, a second low bending stiffness portion, and a soft member arranged in the second high bending stiffness portion and the second low bending stiffness portion. Stiffness of part of the variable stiffness apparatus in a longitudinal axis direction is varied by changing a relative position of the first and second longitudinal members.

Abstract: The present invention relates to an ergonomic bidirectional self-locking mechanism for endoscope angulation control knob operation, which allows for easier access to the endoscope control knobs, reduced muscle exertion for knob operation, and real-time locking of the position of the knobs when turned, as disclosed herein. The invention has benefits for the operator thereof from ergonomic and patient safety perspectives.

Abstract: An endoscope includes a bending portion bendable in all directions including four directions: an up direction, a down direction, a left direction, and a right direction, a bending operation lever configured to bend the bending portion by being tilted, and a wire pulling mechanism provided integrally on the bending operation lever and including a lever tilting angle adjustment mechanism configured to set a first tilting angle at which the bending operation lever is tilted in order to bend the bending portion to at least one direction in the four directions by a predetermined bending angle and a second tilting angle at which the bending operation lever is tilted in order to bend the bending portion in a direction different from the at least one direction by a predetermined bending angle to different angles when the bending operation lever is tilted so as to bend the bending portion.

Abstract: An endoscope including: a bending portion; a first traction member and a second traction member that causes the bending portion to bend; a first rotary member that pulls the first traction member; a first plate member on which the first rotary member and the first traction member are disposed; a first protrusion; a first positioning part that comes into contact with the first rotary member; a second rotary member that pulls the second traction member; a second plate member; a second protrusion; and a second positioning part that comes into contact with the second rotary member.

Abstract: A control unit that includes a braking system for fixing the position of an endoscope tip is provided. The control system includes an up-down control knob and a right-left control knob. The brakes are engaged by rotating the control knob itself counter-clockwise from a free wheeling position. After the brakes have been engaged, a sufficient amount of force applied to the control knobs will move the endoscope tip slightly in the corresponding direction, allowing for fine tuning of tip position after braking.

Abstract: An endoscopic probe extending from a proximal end to a distal end thereof, and configured to be inserted in a tubular lumen to observe a sample is disclosed. The probe includes a first waveguide enclosed within an inner sheath and extending from the proximal end to the distal end along an axis of the inner sheath; and a plurality of second waveguides having at least the distal ends thereof arranged in one or more rings around the inner sheath to surround the distal end of the first waveguide. At the distal end, the axis of each of the second waveguides is tilted with respect to the axis of the first waveguide by a tilt angle which can be adjustable. This novel endoscopic probe has a resultant numerical aperture larger than the numerical aperture of each of the second waveguides, and it may be applicable to forward-viewing spectrally encoded endoscopes (SEE).

Abstract: A bending operation device includes a bending operation member, a bendable part, an operation wire, a pulling wire, and a connection member. The bending operation member is disposed in an operation unit and is supported tiltably in a preset direction. The bendable part is disposed on a side of a distal end of the operation unit. The operation wire is connected at an end thereof to the bending operation member and is pulled or relaxed according to displacement of the bending operation member. The pulling wire is connected to the bendable part and bends the bendable part. The connection member is connected to the operation wire at a first position and is connected to the pulling wire at a second position. The second position is shifted from the first position by a preset angle in a turning direction about a longitudinal axis of the operation unit.

Abstract: An endoscopic system may include an endoscope including a proximal end, a distal end, and an elongated sheath extending therebetween. The elongated sheath may define at least one lumen. The proximal end of the endoscope may include a handle operably coupled to a proximal portion of the elongated sheath. The endoscopic system also may include a clip coupled to the handle of the endoscope. The clip may include at least one retaining arm configured to receive a handle of an auxiliary tool. The at least one lumen may be configured to receive a distal portion of the auxiliary tool. Associated devices and methods are also disclosed.

Abstract: An operation lever type (joystick type) endoscope including an operation lever capable of adjusting a bending angle of a bending portion in response to a tilting operation of an operation portion, and an exterior cover an outer periphery portion of which is watertightly fixed to an operation portion body (an operation portion), and an inner periphery portion of which watertightly covers an outer circumference of the operation lever, the exterior cover being capable of deforming by pressure fluctuation inside the operation portion (that is, pressure fluctuation of a sealed space formed inside the endoscope), is provided with a restricting member 90 configured to restrict expansion of the exterior cover by the fluctuation of the internal pressure.

Abstract: A dilation catheter system includes a body, a guidewire, and a dilation catheter having an elongate shaft. The dilation catheter system may include a locking mechanism to prevent the guidewire from moving relative to the elongate shaft or to lock the guidewire to the dilation catheter to form a fixed wire unit. The dilation catheter system may include a stabilizing tube extending from an actuator, to provide rigidity to the guidewire. The dilation catheter may include a grip element having a plurality of grip features disposed thereon. The dilation catheter may include a cap biased toward a first longitudinal position and movable to a second longitudinal position. A guide catheter secured to the cap is prevented from changing angular orientation in the first longitudinal position and is free to change angular orientation in the second longitudinal position.

Abstract: Methods of inserting a tube through the nasopharynx of a patient are disclosed. The methods of inserting a tube through a nasopharynx of a patient includes the steps of inserting the tube through a naris of the patient; and when a distal end of the tube is proximate a rear surface of the nasopharynx, pulling on or holding in place a thread-like member attached to a tube portion of the distal end of the tube so as to alter an initial direction of the distal end of the tube and point the distal end of the tube towards a throat of the patient. Kits for inserting a tube through the nasopharynx of a patient are also disclosed. The kits include a tube sized so as to move through a nasopharynx of a patient; and a thread-like member that is attachable to a tube portion of a distal end of the tube and can be tensioned so as to alter an initial direction of the distal end of the tube and point the distal end of the tube towards a throat of the patient.

Abstract: Embodiments include a catheter shaft (12) having an elongated structure with a distal portion (18) and proximal portion (16). The distal portion (18) can include a distal tip (36), a proximal connector (38), and a plurality of pivoting hollow cylindrical segments (40) disposed between the proximal connector (38) and distal tip (36) along a longitudinal axis extending through the elongated structure. A plurality of connections (42, 44) can be disposed along diametrically opposed sides of the distal portion (18) and configured to connect the distal tip (36), the pivoting hollow cylindrical segments (40), and the proximal connector (38). A diametrically opposed pair of tabs (54-1, 54-2) can extend from an inner wall of each of the pivoting hollow cylindrical segments (40) to form first and second pullwire tunnels (81-1, 81-2). First and second pullwires (52-1, 52-2) can extend through the first and second pullwire tunnels (81-1, 81-2).

Abstract: A medical device control handle has with a distal component which is adjustable by an actuator assembly by means of a puller member or wire. The actuator assembly includes a user interface rotational dial, a detent tab washer and a spool, where the dial is rotationally coupled to the detent tab washer which transmits rotational movement of the dial to the spool. The spool has a shaft body and a drum end onto which an proximal end portion of the puller member can be wound to manipulate or adjust the distal component. Rotational movement of the detent washer is limited to prevent overrotation and breakage of the puller member. At least one washer is mounted on the shaft body of the spool to help apply compression load on the actuator assembly in friction-inducing contact with one or more components of the actuator assembly.