Abstract: Disclosed is a flexible surgical instrument system, comprising a flexible continuum structure consisting of a distal structure, a middle connecting body and a proximal structure linked in sequence, and further comprising a transmission driving unit linked to the proximal structure. The transmission driving unit comprises a plurality of transmission mechanisms respectively driving corresponding proximal segments. The transmission mechanisms are operable to control the direction of a bending plane of the proximal segments and to control the bending angle of the proximal segments in the bending plane, so as to drive the proximal segments in the proximal structure to bend or turn in any arbitrary direction, and to further drive distal segments in the distal structure linked thereto to bend or turn in the opposite direction.

Abstract: An extension tool includes a plurality of sequentially arranged links moveable to a first position, the plurality of sequentially arranged links rigidly fixed to one another in the first position, the plurality of sequentially arranged links defining a first passage and a second passage, the second passage being separate from the first passage when the plurality of sequentially arranged links are rigidly fixed to one another.

Abstract: A flexible underwater robot, a control method and a device is provided with at least one movable joint and a control module. A flexible joint module of the movable joint comprises a first connecting plate, a second connecting plate, a first spring, several second springs, several third springs, several first pulling ropes, several second pulling ropes and a pulling module. The first spring, the second springs and the third springs are arranged from inside to outside in sequence with gradually decreased rigidities correspondingly to form a gradual rigidity structure, so that it is more flexible to adjust a posture. When the robot is impacted, it may absorb and release energy to ensure the integrity of the flexible joint module, so that the stability is improved.

Abstract: A method comprises providing an articulation tool including an articulation mechanism comprising a proximal link and a distal link, end effector, elongated shaft, rotating member, and an articulation lock comprising a first lock configured to prevent pivoting of the elongated shaft about a yaw axis, a second lock configured to prevent pivoting about a pitch axis, and an actuator to actuate both locks simultaneously. The method further comprises driving movement of the proximal link which causes corresponding movement of the distal link, adjusting the actuator between an unlocked configuration and a locked configuration in which the links and end effector are held in a fixed orientation with respect to the elongated shaft, and driving rotation of the rotating member which causes rotation of the elongated shaft while the links and end effector are held in the fixed orientation and rotation of the end effector about the end effector longitudinal axis.

Abstract: Disclosed is a flexible surgical instrument system (100), comprising a flexible surgical instrument (10) composed of a distal structural body (11), a proximal structural body (12), a driving transmission mechanism (13) and a middle connecting body (14), wherein a surgical end effector (111) is located at a distal end of the distal structural body (11), a proximal end of the distal structural body (11) is linked to the middle connecting body (14), and the driving transmission mechanism (13) is linked to the proximal structural body (12) via the middle connecting body (14); the distal structural body (11) comprises at least one distal structural segment (112, 113), wherein each distal structural segment (112, 113) comprises a distal fixing disk (115, 118) and structural backbones (116, 119); the proximal structural body (12) comprises at least one proximal structural segment (120, 121), wherein each proximal structural segment (120, 121) comprises a proximal fixing disk (122, 126), structural backbones (124, 12

Abstract: The soft bodied structures and systems for controlling such devices are described herein. The soft bodied structures can, through a series of soft hydraulic actuators, move from a first position to a second position by a somersaulting motion. The system can include connecting to a first contact point of the surface using a surface attachment. The rigidity of the controllably resistive material can then be increased. The medial hydraulic actuators can be actuated to expand the exterior medial surface, creating a bend. The device can then attach to a second contact point using the surface attachment and the end portion actuator of the unattached end portion. Then, the surface attachment of the first attached end portion can detach. The medial hydraulic actuators and the controllably resistive material can then relax, followed by detaching the surface attachment of the second attached end portion.

Abstract: An apparatus including a tendon-driven device such as an endoscope comprising a bendable body, a tendon attached to and extending a length of said body, and an actuator that will actuate said tendon based on a control signal from a controller. The controller is configured to send said control signal to said actuator and comprises a forward-kinematic-mapping unit that estimates an angular displacement, wherein the kinematic-mapping unit is configured for: providing a tension value of the tendon to obtain a desired angular displacement wherein the tension has a nonlinear relationship with the desired angular displacement based on information of friction where the tension is greater that would be calculated without including the effect of friction. The friction coefficient may be determined as it changes over time.

Abstract: An insertion apparatus includes an insertion end positionable within a cavity and configured to travel through the cavity, a steering end opposite the insertion end, and a body extending from the insertion end to the steering end and sized to fit within the cavity. The body includes a plurality of members flexibly coupled together and individually actuated. Each member of the plurality of members includes at least one actuator strand. At least one member of the plurality of members has a first configuration in which the at least one member of the plurality of members has a first stiffness and a second configuration in which the at least one member of the plurality of members has a second stiffness greater than the first stiffness. At least a portion of the body is flexible to facilitate travel of the body through the cavity when the at least one member of the plurality of members is in the first configuration.

Abstract: Disclosed is a variable geometry and constant-volume inflatable tube, including an inflatable envelope having a central axis. A stress-bearing unit is provided, including a pair of first and second inextensible link belonging to a same longitudinal half-plane of the envelope, the first unit being oriented along a first longitudinal direction inclined with respect to the central axis and the second unit being oriented along a second longitudinal direction which is also inclined with respect to the central axis but which crosses the first direction on the central axis. The inflatable tube can be bent around a first or second pivot axis, the longitudinal tensile stresses applied to the envelope then being concentrated on the central axis.

Abstract: A force transmission transmits forces received by three levers to an input gimbal plate having three support points. The input gimbal play may in turn transmit the force to a wrist assembly coupled to a surgical tool. A first gimbal support point is supported by a first lever having a fulcrum with one degree of rotational freedom. Second and third gimbal support points may be supported by second and third levers having fulcrums with two degrees of rotational freedom. These fulcrums may include a first axle coupled to the lever and a second axle that supports the first axle and provides the fulcrum for the supported lever. A spring may draw the second and third levers toward one another. The force transmission may include a parallelogram linkage that includes a rocker link pivotally coupled to the first lever and having a flat surface that supports the first gimbal support point.

Abstract: Some embodiments of the invention relate to a mechanism for actuating a shaft having two degrees of freedom, comprising: a first actuator configured to rotate the shaft around the shaft axis, and a second actuator configured to bend the shaft using one or more elongated elements attached to the shaft, wherein actuation of the first actuator indirectly manipulates the elongated elements controlled by the second actuator, thereby affecting operation of the second actuator. Some embodiments relate to motorized actuation of a system comprising at least one surgical arm.

Abstract: A robot includes: a first arm rotatable about a first rotation axis; a second arm provided on the first arm rotatably about a second rotation axis that is a different axial direction from an axial direction of the first rotation axis; and a moving part provided on the second arm rotatably about a third rotation axis. The moving part has a third arm and a fourth arm. A maximum length of the moving part is longer than a length of the second arm and shorter than twice the length of the second arm. The first arm has a length longer than the length of the second arm. The first arm and the second arm can overlap with each other, as viewed from the axial direction of the second rotation axis.

Abstract: A robotic mount is disclosed that attaches onto any appropriate stand, framework, or other support structure. The mount can manipulate the position and orientation of affixed devices upon remote command received from any network connected device. A specific or sequence of positions/orientations can be precisely registered and promptly returned to on command.

Abstract: A robot system includes: a cell; and a robot which is provided to move in the cell, in which the robot includes an n-th (n is an integer which is equal to or greater than 1) arm which rotates around an n-th rotating axis, and an (n+1)th arm which is provided to rotate around an (n+1)th rotating axis which is an axial direction different from an axial direction of the n-th rotating axis, in the n-th arm, in which the length of the n-th arm is longer than the length of the (n+1)th arm, and in which, when viewed from the (n+1)th rotating axis, the n-th arm and the (n+1)th arm overlap each other.

Abstract: A robot system including a first motor capable of normal and reverse rotation, a second motor capable of normal and reverse rotation and spaced apart from the first motor, pulleys coupled to rotating shafts of the first and second motors, respectively, a frame, a moving arm including a mount slidably mounted on the frame and including a free end positioned opposite the mount in a longitudinal direction, a carriage mounted on the moving arm such that the carriage is slidable in a direction perpendicular to a slide direction of the moving arm, a belt wrapped around the pulleys and connected to the carriage, and a plurality of idlers for guiding the belt. It is possible not only to control a position of the carriage by resultant force of the first and second motors but also to precisely control the carriage by the simply structured moving arm having the free end.

Abstract: A robot includes a robot arm having an nth (n is an integer equal to or more than one) arm and an (n+1)th arm, the nth arm is rotatable about an nth rotation shaft, the (n+1)th arm is provided on the nth arm rotatably about an (n+1)th rotation shaft in a shaft direction different from a shaft direction of the nth rotation shaft, and, while a distal end of the robot arm is moved from a first point to a second point, a first operation such that the nth arm and the (n+1)th arm overlap as seen from the shaft direction of the (n+1)th rotation shaft and a second operation of rotating the nth arm are performed.

Abstract: A robot includes: a base; a first arm provided on the base rotatably about a first rotation axis; and a second arm provided on the first arm rotatably about a second rotation axis that is a different axial direction from an axial direction of the first rotation axis. The first arm and the second arm can overlap with each other, as viewed from the axial direction of the second rotation axis. The first arm is bent.

Abstract: A robot includes a first member, a second member which is provided on a first member and rotates around a rotation shaft, a driving unit which is provided in the second member, and an operation shaft which is driven by the driving unit and is provided in the second member, the first member includes a first portion and a second portion which has a smaller width than that of the first portion, when seen in a direction orthogonal to a plane including the rotation shaft and the operation shaft, and the second member is connected to the second portion.

Abstract: Apparatus and methods that can be used to stabilize a portion of an extended-reach tool assembly to enable the dimensional mapping, non-destructive inspection and/or simple repair of elongated and serpentine structures used in aerospace and military platforms. In some embodiments, a jointed (i.e., articulated) arm of the extended-reach tool assembly, which is mounted and manipulated at the entrance to a limited-access space (e.g., a cavity), is equipped with actuatable contact pads or bladders to stabilize the distal end of the arm to which a tool-carrying end effector is coupled. The end effector is capable of holding and orienting a probe or sensor (e.g., NDI sensor unit, laser scanner, camera, etc.) or other tool (e.g., drill, sander, vacuum, “grabber”, coating sprayer, etc.).

Abstract: This multi-articulated manipulator is rich in reliability and follow-up property in medical applications. The multi-articulated manipulator is composed of more than one hollow outer shell, joint members to connect the outer shells each other, a grasping member fastened for rocking movement to the foremost outer shell, and a power transmission shaft to actuate the grasping member and the outer shell in a bending manner independently from each other. The power transmission shaft is composed of a universal join allowed to bend independently from each other and transmit the rotating torque, and a transmission shaft capable of making expansion and shrinkage and able to transmit rotating torque. The power transmission shaft at the foremost end thereof has male threads mating with the nut made at the boss portion inside the outer shell.

Abstract: A coupler to transfer controller motion from a robotic manipulator to a surgical instrument includes a pin having a tip with a bearing surface and a plate having a driving surface that bears against a gimbal assembly in the surgical instrument. The plate has a surface supported on the bearing surface of the pin. The bearing surface has a center that coincides with an intersection of two rotational axes of the gimbal assembly. The plate is rotated about the center of the bearing surface to transfer controller motion to the surgical instrument. There may be alignment features on the driving surface of the plate to mate with corresponding features on an inner gimbal of the gimbal assembly. An actuator arm may be connected to one side of the plate. An actuator mechanism may be connected to the actuator arm to rotate the plate about the center of the bearing surface.

Abstract: A robotic arm includes a motor, a ball screw spline shaft and a ball nut connected to the motor and attached to the ball screw spline shaft in such a manner that when the motor is started, the ball nut is rotated by the motor, and the ball screw spline shaft is forced to carry a movable seat linearly, causing the movable seat to synchronously move a tension bar to the position where a stopper member at the tension bar is stopped at a mount, and thus the movable seat can be pulled by the tension bar to bias a grip.

Abstract: A cochlear implant device includes a deformable and stretchable flexible strip composed of a biological compatible material and positioned about a longitudinal axis so as to form a spiral. The implant device has a plurality of conductive strips with electrode windows formed so as to expose a segment of each conductive strip. A density of the electrode windows is sufficient to monitor a distance of the flexible strip from a non-conductive tissue of a patient in a 360 degree field of view about the longitudinal axis. A method of inserting a cochlear implant includes providing a multi-joint robot comprised of a series of actuator units, guiding the multi-joint robot into an inner ear of a patient, monitoring the position of the multi-joint robot relative to a non-conductive portion of the patient; and applying current to the multi joint robot so as to adjust the position of the actuator units.

Abstract: A method of transmitting controller motion from a robotic manipulator to a surgical instrument includes rotating a plate included in the robotic manipulator. The plate has a driving surface that bears against an inner gimbal of a gimbal assembly included in the surgical instrument. The plate is rotated about a center of motion that coincides with an intersection of two rotational axes of the gimbal assembly.

Abstract: A robot arm link comprises a base, a first section rotationally coupled to the base, a second section pivotally coupled to the first section and a third section attached to the second section and having a fixed portion and a movable portion, the movable portion coupled to the fixed portion for movement between first and second portions, the movable portion having an attachment plate for attachment to another robot arm link. The links can be used to construct an arm with multiples of three degrees of movement. For example, three links are joined together and mounted on a rotation base and terminated with a pivot or wrist joint to provide a total of 11 degrees of movement.

Abstract: A continuum style manipulator is actuated by jammable media within an envelope of a module, which is also actuated by a tensile element, such as a cable and spooler motor. Multiple modules may be reversibly added. Two or more tensile elements may also be used. Three or more actuated tensile elements can actuate three DOFs of each module, and the terminal module, as well as the entire manipulator. Jammable media may be granular, actuated by a pressure change. Coarsely ground coffee works well. Rather than a jammable media, tensile elements may alternatively be used with other phase change media, such as magnetorheological and electrorheological media. A high friction angle of the granular media is desirable, and has been achieved with a particle size dispersion including both small and relatively larger particles. Applications include endoscopes, proctoscopes, laparoscopic instruments, manufacturing and medical manipulators.

Abstract: A substrate processing apparatus comprising a transport arm having serially connected arm links, at least one of the arm links having a predetermined arm link height, at least a first pulley and a second pulley, where the second pulley is fixed to an arm link of the serially connected arm links, and at least one torque transmission band extending longitudinally between and coupled to each of the first pulley and the second pulley, the at least one torque transmission band having a corresponding band height for the predetermined arm link height and a variable lateral thickness such that the at least one torque transmission band includes a segment of laterally increased cross section for the corresponding band height.

Abstract: An apparatus having a member that revolves about a remote center of motion (RCM) and a base link coupled to a mounting fixture. A first and second link are pivotably coupled to the member at respective distances from the RCM and are translatable relative to the base link along a first direction, at a fixed ratio of displacement. The ratio of respective distances equals a fixed ratio of displacement. The apparatus has a translational motion generator for a first and second element along parallel opposing directions. The translational motion generator is disposed on the first link and enables motion parallel to the first direction. The base link is fixed in position, the first element is fixed to the base link and the second element is fixed to the second link, such that the first and second link may translate relative to the base link with fixed ratio of displacement.

Abstract: Disclosed is a manipulator including a wire driving actuator to bend base and terminal sections of a joint assembly in multiple directions by a base section wire and a terminal section wire. The terminal section driving wire is operatively connected to the base section driving wire such that the terminal section driving wire is moved by a distance equal to a movement distance of the base section driving wire. Accordingly, it is possible to prevent bending of the terminal section upon bending the base section.

Abstract: A flexible tool comprises stiffening means switchable in use from a first state of relatively low stiffness to a second state of relatively high stiffness, and subsequently switchable from the second state back to the first state.

Abstract: A head structure of a robot according to the invention includes a first motor and a second motor so supported side by side within a head of the robot that output shafts are positioned coaxially with each other; a left elastic frame that is so driven by the first motor and one end of which is so fitted as to be rotatable around the output shaft and the other end of which extending in a perpendicular direction from the output shaft is supported by a trunk of the robot; and a right elastic frame that is so driven by the second motor and one end of which is so fitted as to be rotatable around the output shaft and the other end of which extending side by side with the left elastic frame from the output shaft is supported by the trunk.

Abstract: An actuating member for causing a flexible elongated member for medical use to perform a predetermined curving motion includes a push-pull member including a first moving part and a second moving part which are configured to be movable relative to one another in an axial direction of the elongated member, the first moving part and the second moving part being pushable and pullable so as to cause the elongated member to curve in the axial direction of the elongated member; a curving motion restricting member which is configured to be movable in the axial direction of the elongated member, and which is configured to restrict curving of at least a portion of the elongated member; and an operation member configured to operate movements of the first moving part, the second moving part, and the curving motion restricting member.

Abstract: An instrument that facilitates bending with large degrees of articulation while maintaining ease of manufacturing for medical and surgical applications is discussed.

Abstract: A linear actuator suitable for mobilizing a load comprises: a leg linked to the load by one of its ends with a ball joint with three degrees of freedom in rotation; a plate that is mobile in translation along an axis belonging to a plane of a support of the actuator, said mobile plate being mechanically linked to the leg by its other end. The linear actuator also comprises at least one first elastic cable, fixed by one of its ends to the mobile plate, and fixed by its other end to the support, being engaged in a first pulley fixed to the support. The actuator can notably be used to mobilize a simulation platform mounted on a hexapod.

Abstract: Disclosed herein are a robot joint driving method, computer-readable medium, and device assembly which conducts motions similar to those of humans, and a robot having the same. These motions are achieved by arranging joint driving devices suited to characteristics of respective joints. The robot joint driving device assembly includes a tendon-type joint driving device using a wire, and a harmonic drive-type joint driving device using a gear reduction method. The tendon-type joint driving device is used to drive a rotary joint requiring high back-drivability, and the harmonic drive-type joint driving device is used to drive a rotary joint requiring high rigidity and high precision.

Abstract: A dual arm robot assembly has two arms each having a set of joint/link pairs that, in conjunction with an actuator assembly. Define at least three degrees of freedom to provide independent horizontal translation and rotation of a distalmost link. A vertical motion mechanism is also provided.

Abstract: A flexible surgical instrument employs sheaths around tendons that actuate an end effector or other mechanisms in a distal tip of the instrument. A liquid lubricant can be introduced in the sheaths to reduce friction, and the sheaths can be porous or non-porous. The lubricant can be confined, for example, with an o-ring or a bellow seal, to keep lubricant from leaking where the tendons extend out of the sheaths. More generally, the distal end of the instrument is sealed to prevent leakage of lubricant into a patient. To further reduce risks, a non-toxic water-based lubricant can be used.

Abstract: A holding arm apparatus 1 is configured to connect upper and lower timing pulleys 5A and 6A of a vertical arm unit 4 to each other with a timing belt 15, to widen the range of rotation angle of a horizontal arm unit 5 and allow the position and angle of an endoscope 20 held at a front end of the horizontal arm unit 5 to be widely changed. The horizontal arm unit 5 and a counterweight 6 turn by the same angle, to maintain a weight balance by the counterweight 6. Using the timing belt 15 reduces the total weight and operation noise of the holding arm apparatus 1. Accordingly, the apparatus is appropriate for a medical front.

Abstract: The present invention relates to a tongue module for a robot which is installed in an android face robot formed to have a similar external appearance to a human face and to express feelings. The tongue module includes a tongue body made of composite silicon material and formed to have smooth texturing; a front and rear driving unit configured to move the tongue body in front and rear directions by using a crank arm and a first servo motor; an up and down driving unit configured to bend the tongue body in up and down directions by using wires and a second servo motor; and a linear rail assembly configured to move the tongue body in a straight line.

Abstract: A robotic positioning apparatus configured for moving an element from an initial position to a target position. The apparatus includes a moveable member attachable to an element to be moved; at least one tensile support member for supporting the movable member; and at least one tensile positioning member for repositioning the moveable member. The at least one tensile positioning member is configured to maintain the at least one tensile support member in tension. The at least one tensile support member is configured to maintain an inclination of at least a portion of the moveable member during repositioning.

Abstract: An apparatus for driving an articulating probe comprises an elongate probe constructed and arranged to articulate in at least one predetermined degree of motion and to transition from a flexible state to a rigid state, and a force transfer mechanism constructed and arranged to apply a force to the probe. The force is selected from the group consisting of a force that causes probe to articulate in the at least one predetermined degree of motion and a force that causes the probe to transition from the flexible state to the rigid state. The base structure is attached to portion of the force transfer mechanism and the elongate probe; the base structure comprising one or more stabilizing elements constructed and arranged to resist undesired movement of the probe caused by force from the force transfer mechanism.

Abstract: The invention concerns a fluidically operable manipulator made up of several manipulator segments stacked along an extension curve, each comprising at least one connecting plate and at least two fluidically separated fluid chambers spaced apart on the connecting plate at right-angles to the extension curve, wherein each of the fluid chambers has at least one elastically deformable wall section which is designed to make possible, on pressurization of the respective fluid chamber with a fluid, a change in volume of the fluid chamber for a linear movement substantially parallel to the extension curve, and wherein a main extension surface of the connecting plate is provided for an arrangement at least substantially at right-angles to the extension curve, wherein the two or more fluid chambers are made integral with the connecting plate or plates.

Abstract: A method and apparatus for moving and positioning a gripping unit (3; 23; 43), in which method the gripping unit is moved and positioned by intermediation of cables (9, 10, 11, 12; 29, 30, 31; 48, 49, 50), so that at least one degree of freedom of the gripping unit is removed by fastening the gripping unit mechanically (4; 24; 44) to the support structure. A robot (1; 21; 41) provided with this kind of apparatus is also described.

Abstract: A flexible and steerable structure for non-destructive inspection, the structure including a longitudinal body and at least one actuator enabling the curvature of at least a portion of the longitudinal body to be modified, the actuator being carried by a support associated with the longitudinal body and including a distal portion that is spaced apart or that is spaceable apart from the longitudinal body and that is connected to a portion of the longitudinal body by a traction line.

Abstract: A multi jointed robot arm includes at least first and second link members connected by a connection arrangement and at least a first control cable. First and second ends of the first control cable engage with first and second engagement point of the first link member and first and second attachment points of the second link member. The assembly further includes a first actuator configured to selectively tension the first and second ends of the first control cable such that the second link member pivots toward a first or second side, wherein the connection arrangement is arranged to pivot at a first pivot point located substantially along a notional line extending between the first and second attachment points, and to pivot at a second pivot point extending between the first and second engagement points.

Abstract: A steerable multi-linked device may include a first multi-linked mechanism and a second multi-linked mechanism. At least one of the first multi-linked mechanism and the second multi-linked mechanism may include a first link, a plurality of intermediate links, a second link movably coupled to a second one of the intermediate links and a reinforcing member. A first one of the intermediate links may be movably coupled to the first link, and the reinforcing member may extend from a first end of a third one of the intermediate links toward a second end of the third one of the intermediate links.

Abstract: A remote controlled actuator includes a spindle for holding a tool, a spindle guide section of an elongated configuration, a distal end member rotatably supporting the spindle, and a drive unit housing connected to a base end of the spindle guide section. The distal end member is fitted to the spindle guide section for alteration in attitude. The spindle guide section includes an outer shell pipe, a rotary shaft, and guide pipe. Within the guide pipe, an attitude altering member is inserted to alter the attitude of the distal end member. A connection device detachably connects the spindle guide section with the drive unit housing.

Abstract: According to one aspect, this invention provides an apparatus for varying the stiffness of a leg of a robotic system. The apparatus includes a compliant spine assembly including a compliant spine mounted for movement adjacent the leg and a rack coupled to the compliant spine. It also includes a motor assembly positioned to move the compliant spine of the compliant spine assembly with respect to the leg, the motor assembly including a gear engaging the rack of the compliant spine assembly and a motor coupled to drive the gear. The compliant spine of the compliant spine assembly is configured to vary the stiffness of the leg of the robotic system as it is moved by the motor assembly with respect to the leg.

Abstract: An instrument for endoscopic applications, including a tubular member having a handling end portion having a flexible portion and actuating devices located at the other end portion, and longitudinal elements for transferring the movement of the actuating devices to the handling end portion resulting in a change of orientation thereof, whereby the handling end portion includes at least two independent flexible portions, whereby the actuating end portion has a corresponding number of actuating devices, and whereby each actuating device is connected by its own set of longitudinal elements to a part of the handling end portion for effecting a change of orientation of one of the flexible portions.

Abstract: A robot includes a first actuator, a first rotating body, a second actuator, and a second rotating body. The first actuator rotationally drives a second wrist that is connected to a first wrist. The first rotating body transmits a drive force of the first actuator to a second wrist. The second actuator rotationally drives a third wrist that is connected to the second wrist. The second rotating body transmits a drive force of the second actuator to the third wrist. The first rotating body and the second rotating body are arranged at positions where rotation axes of the first and second rotating bodies are parallel with each other and do not interfere with each other in such a manner that the position of the first rotating body is within a range of the second rotating body when viewed from a direction perpendicular to the rotation axis of the second rotating body.