Abstract: A surgical instrument is inserted through a guide tube. A telemanipulation system moves the distal end of the surgical instrument in all six Cartesian degrees of freedom independently of any guide tube movements.

Abstract: A device for constructing an assembly of building components includes an articulating arm unit and a gripper/nailer mounted on an end of the articulating arm unit. The gripper/nailer includes a gripping unit for grasping building components and positioning them in a predetermined arrangement and a nailing unit for inserting a fastener to secure the building components together.

Abstract: A redundantable robotic mechanism is disclosed for improving reliability of tranport equipment. The redundantable robot assembly typically comprises independent robots with separate controls, motors, linkage arms, or power, thus providing the capability of operation even if parts of the assembly are not operational or when parts of the assembly are removed for repair. The redundantable robot assembly can be also designed to allow in-situ servicing, e.g. servicing one robot when the other is running. The disclosed redundantable robot assembly provides virtual uninterrupted process flow, and thus greatly increases the yield for the manufacturing facility.

Abstract: A laser processing head mounted on a robot arm moves from with a constant speed in a direction from a welding point to a next welding point, while a reflection mirror continuously turns in order to maintain laser beams focused on the welding point until the welding at the welding point is completed, and the reflection mirror quickly turns to shift the focus of the laser beams onto the next welding point when the welding at the welding point is completed.

Abstract: A horizontal multijoint type robot is so constructed that it comprises a first arm connected through a first joint shaft to a base, a second arm connected through a second joint shaft to the first arm, and a working shaft provided rotatably and movably up and down on the distal end of the second arm, and that the arm length L1 of the first arm and the arm length L2 of the second arm are equal to each other so that the second arm is able to overlap the first arm.

Abstract: A legged robot that runs while repeating a jump cycle including a ground-contact phase from a landing to a takeoff and an aerial phase from a takeoff to a landing is provided. The legged robot adjusts the landing timing after a jump in accordance with a planned timing, thereby attaining a smooth landing. A measuring unit of the legged robot measures an actual aerial phase period in a k-th jump cycle. A subtractor calculates a time difference between a target aerial phase period and the actual aerial phase period in the k-th jump cycle. A target velocity determining unit calculates a target vertical velocity of a center of gravity on a takeoff timing in a (k+1)-th jump cycle so as to eliminate the time difference. Motors in respective joints are controlled so as to realize the calculated target vertical velocity in the (k+1)-th jump cycle.

Abstract: A device for machining components, in particular of a vehicle body has a transport and positioning unit for the component and several machining stations, which are arranged around said unit and to which the component held by a component holder of the transport and positioning unit can be fed in a position ready for machining. To transport the component from one machining station to the other machining stations while taking up the smallest possible surface area, the transport and positioning unit includes a rotor and a pivoting arm that is mounted eccentrically on said rotor, driven in opposition to the latter and supports the component holder. The drives of the rotor and the pivoting arm are synchronized in such a way that the component holder is displaced along a closed curved path comprising spaces between the neighboring apexes of said path.

Abstract: A robotic apparatus has eight actuators (M0-M7) and a linkage (LINK 0-LINK 5) that actuates an end effector. Three serial macro freedoms have large ranges of motion and inertias. Four serial micro freedoms have small ranges of motion and inertias. Translation of the end effector in any direction is actuated by at least one micro joint and at least one macro joint. The apparatus can be part of a master and slave combination, providing force feedback without any explicit force sensors. The slave is controlled with an Inverse Jacobian controller, and the mater with a Jacobian Transpose controller. A slave having more degrees of freedom (DOFs) than the master can be controlled. A removable effector unit actuates its DOFs with cables. Beating heart surgery can be accomplished by commanding the slave to move with a beating heart and cancelling out any such motion in the motions perceived by the master.

Abstract: According to an embodiment, a numerically controlled (NC) processing system includes materials processing installation having a multi-axis kinematic linkage operable to position a tip portion of the linkage along a predetermined process path. The system also includes a processor having a compensation system operable to detect a singular point in the process path and to improve the accuracy tip portion positioning near the singular point.

Abstract: A target position detection apparatus for a robot includes: a robot including an arm configured to be freely moved in at least two directions of X and Y axes, the arm having a wrist axis provided at a distal end of the arm and configured to be freely moved in a horizontal direction, and the wrist axis being provided with an end effector; and a control unit adapted for driving a memory to store a teaching point therein and controlling an operation of the robot such that the end effector will be moved toward the teaching point stored in the memory.

Abstract: A shoulder joint is provided. The shoulder joint includes a main support, a fold-out arm, first and second carriages arranged on the main support, and a first coupling that is operable to couple the first and second carriages together. The fold-out arm is attached by a pin to the second carriage, and the first carriage is connected to the fold-out arm in such a way that when the first and second carriages are operable to move towards each other, the fold-out arm is folded out by pivoting around the pin. The first coupling is operable to couple the first and second carriages together when the fold-out arm is folded out, and the first and second carriages are operable to move jointly in at least one direction when coupled together.

Abstract: An umbilical member motion limiting device is provided on a robot which has a forearm, a wrist portion, an operating tool attached to the end of the wrist portion, and the umbilical member connected to the operating tool through the forearm, for limiting the motion of the umbilical member corresponding to the motion of the robot. The motion limiting device comprises a swing portion attached to the wrist portion so as to swing around a swing axis and a limiting portion arranged on the swing portion for limiting the motion of the umbilical member. Thus, the motion limiting device can minimize interference due to surplus length of the umbilical member and avoid contact of the umbilical member with external equipment.

Abstract: A parallel robot including a movable-section drive mechanism having a parallel mechanism configuration and operating to allow a movable section to perform a three-axis translational motion with respect to a base section, and a wrist-section drive mechanism operating to allow a wrist section to perform a three-axis orientation-changing motion with respect to the movable section. The wrist section includes a first rotary member supported on the movable section and rotatable about a fourth rotation axis different from axes of the three-axis translational motion of the movable section, a second rotary member connected to the first rotary member and rotatable about a fifth rotation axis orthogonal to the fourth rotation axis, and a third rotary member connected to the second rotary member and rotatable about a sixth rotation axis orthogonal to the fifth rotation axis. The third rotary member is provided with an attachment surface to which a tool is attached.

Abstract: A horizontal multijoint type robot is so constructed that it comprises a first arm connected through a first joint shaft to a base, a second arm connected through a second joint shaft to the first arm, and a working shaft provided rotatably and movably up and down on the distal end of the second arm, and that the arm length L1 of the first arm and the arm length L2 of the second arm are equal to each other so that the second arm is able to overlap the first arm.

Abstract: A robot includes an articulation mechanism that includes a pair of opposing bevel gears, a pair of motors that rotate the pair of opposing bevel gears independently of each other, an output bevel gear that is engaged with each of the pair of opposing bevel gears and is supported so as to be rotatable and so as to be swingable in rotational directions of the pair of opposing bevel gears, and an output body that is secured to the output bevel gear, a cover-and-support structure that is a supporting member and functions as a cover covering the outside of the entirety of the articulation mechanism, and a swing mechanism that supports the cover-and-support structure such that the cover-and-support structure is swingable in the rotational directions of the pair of opposing bevel gears.

Abstract: The invention relates to a device for swiveling an object around a stationary axis (16) which lies outside the space occupied by the device. The inventive device is characterized by unusually great rigidity. A supporting coupler (5) and a guiding coupler (10) are guided parallel to the frame (1) with the aid of cross-sliding elements. The supporting coupler (5) and the guiding coupler (10) are connected to a crank (4) by means of one respective revolute joint, the crank (4) guiding the supporting coupler (5) and the guiding coupler (10) along concentric, non-identical circular paths. The supporting coupler (5) and the guiding coupler (10) are provided with a second revolute joint located at the same distance from the first revolute joint, i.e. a revolute joint (5b) for the supporting coupler at the output end and a revolute joint (10b) for the guiding coupler at the output end, via which the two couplers (5, 10) are jointly connected to an output member (9).

Abstract: A robotic arm comprising a plurality of segments, each comprising articulated links, and means for causing each segment to bend so the arm can follow a serpentine path. A helical spring is provided coaxially with the arm to urge the links to an initial datum position, and to distribute the bending over the links of each segment.

Abstract: In exemplary implementations of this invention, an input/output device (“Bulb”) is attached to on an articulated, actuated robotic arm. The robotic arm can move the Bulb by translating it along three axes and by rotating it about the arm's base. In addition, the I/O can rotate about its own vertical axis. The Bulb comprises at least a pico-projector, two cameras, a depth sensor and an onboard computer. The onboard computer controls actuators in the robotic arm and Bulb that move the Bulb. It also processes visual data captured by the cameras in order to recognize objects or events, and to respond to them. This response may include changing the position of the Bulb or changing the parameters of an image projected by the pico-projector.

Abstract: A control method and system for controlling a hydraulically actuated mechanical arm to perform a task, the mechanical arm optionally being a hydraulically actuated excavator arm. The method can include determining a dynamic model of the motion of the hydraulic arm for each hydraulic arm link by relating the input signal vector for each respective link to the output signal vector for the same link. Also the method can include determining an error signal for each link as the weighted sum of the differences between a measured position and a reference position and between the time derivatives of the measured position and the time derivatives of the reference position for each respective link. The weights used in the determination of the error signal can be determined from the constant coefficients of the dynamic model. The error signal can be applied in a closed negative feedback control loop to diminish or eliminate the error signal for each respective link.

Abstract: An imaging apparatus comprising a ring-shaped gantry is provided. The gantry has a rotor arrangement rotating therein and a radiation source as well as at least one radiation detector. The gantry has at least one gantry segment which can be detached from the ring shape to allow the gantry to be opened laterally. The gantry is arranged on a supporting structure so as to be movable in space. The supporting structure is a floor, wall or ceiling mounted articulated-arm robot having at least four, preferably six, degrees of freedom of movement. The gantry has at least two radiation sources disposed offset by an angle on the rotor arrangement and associated with each of which is at least one radiation detector.

Abstract: A fiber application machine for the production of composite material parts, comprising a system for displacing a fiber application head, a fiber storage, and a fiber conveyor for conveying the fibers from the fiber storage to the application head, the fiber conveyor being placed in the internal passage of at least one flexible tubular sheath, the machine further comprising a cooling system adapted to inject cold gas in the internal passage of the sheath.

Abstract: A parallel robot of the SCARA type includes a base or a body to which two articulated elements are attached, each including an arm and a forearm that are connected by a joint and are mounted in a manner allowing rotation about one and the same geometrical axis. The two articulated elements are attached to two annular segments, respectively, that form two movable parts of a circular motor whose stator at least partially forms the body, these two movable parts being assigned to one and the same circular path of the stator. Preferably, the two movable parts are guided through one and the same guideway in order to ensure that these two movable parts rotate very precisely about the same geometrical axis.

Abstract: A managing structure for an umbilical member includes a flexible conduit for leading an umbilical member inserted therein from a front arm of a robot to a working tool mounted on a wrist of the robot, a first conduit mounting portion provided adjacent to the front arm, and a second conduit mounting portion provided adjacent to a point where the umbilical member is connected to the working tool. One end of the conduit is attached to the first conduit mounting portion, while the other end of the conduit is attached to the second conduit mounting portion. The conduit is laid so that a section thereof between the first conduit mounting portion and the second conduit mounting portion does not contact the body of the robot.

Abstract: A parallel robot including a movable-section drive mechanism having a parallel mechanism configuration and operating to allow a movable section to perform a three-axis translational motion with respect to a base section; and a wrist-section drive mechanism operating to allow a wrist section to perform a rotational motion with respect to the movable section.

Abstract: Disclosed is a computer-integrated surgery aid system for minimally invasive surgery and a method for controlling the same. The system includes a surgery planning system for creating three-dimensional information from two-dimensional images obtained by means of biplanar fluoroscopy so that spinal surgery can be planned according to the image information and a scalar-type 6 degree-of-freedom surgery aid robot adapted to be either driven automatically or operated manually.

Abstract: A method of operating a surgical system. The method includes obtaining a magnetic resonance imaging (MRI) scan in which magnetic resonance (MR) visible targets are located; registering a robotic arm to the MRI scan using a digitizing tool, the robotic arm including: multiple joints and multiple degrees of freedom; an MR-compatible structural material; multiple MR-compatible joint motors; multiple MR-compatible joint encoders; and an end effector holding an MR-compatible surgical tool having a tool tip; and displaying a location of the tool tip relative to an image from the MRI scan.

Abstract: Apparatus and method for visualizing air stream by little threads on aerodynamic surfaces such that strips of adhesive tape populated with threads are automatically fabricated.

Abstract: Provided is a strain wave gearing having a high stiffness and no limitation imposed on rotation, and a robotic arm including the strain wave gearing. A strain wave gearing includes an electric motor and a strain wave gearing reducer. The strain wave gearing reducer includes: an outer ring member including a first internal gear; a pair of second internal gears each having internal teeth formed along an inner periphery thereof, and the pair of second internal gears differing from the first internal gear in number of teeth; a flexible gear; and a cam member, which distorts the flexible gear in a radial direction to cause the flexible gear to engage with the first internal gear and the pair of second internal gears. The pair of second internal gears is fixed to a pair of fixing plates coupled to each other by a shaft penetrating the cam member.

Abstract: Based upon a force in a vertical direction exerted between an object and a hand and an angle made by the hand relative to a horizontal face, a transporting force estimation unit estimates a transporting force applied in the vertical direction by a person, and based upon the estimated force, a force controlling operation is carried out so as to set a force in the vertical direction of the robot arm of a robot system to a predetermined force.

Abstract: A substrate transport apparatus including a drive section having at least one drive shaft and at least two scara arms operably coupled to the at least one drive shaft, the at least one drive shaft being a common drive shaft for the at least two scara arms effecting extension and retraction of the at least two scara arms, wherein the at least two scara arms are coupled to each other so that, with the at least one drive shaft coupled to the at least two scara arms, rotation of the drive shaft effects extension and retraction of one of the at least two scara arms substantially independent of motion of another of the at least two scara arms.

Abstract: Methods and apparatus are provided for the use of a dual Selective Compliant Assembly Robot Arm (SCARA) robot. In some embodiments two SCARAs are provided, each including an elbow joint, wherein the two SCARAs are vertically stacked such that one SCARA is a first arm and the other SCARA is a second arm, and wherein the second arm is adapted to support a first substrate, and the first arm is adapted to extend to a full length when the second arm supports the first substrate, and wherein the first substrate supported by the second arm is coplanar with the elbow joint of the first arm, and the second arm is further adapted to move concurrently in parallel (and/or in a coordinated fashion) with the first arm a sufficient amount to avoid interference between the first substrate and the elbow joint of the first arm. Numerous other embodiments are provided.

Abstract: A shoulder joint is provided. The shoulder joint includes a main support; a fold-out arm including an upper arm and a lower arm, the upper arm operable to pivot about a pin and the lower arm operable to pivot on a spindle on one end of the upper arm; and a first wheel attached to the pin, and a second wheel attached to the spindle. The upper arm and the lower arm are mechanically linked via the two wheels in such a way that rotation of the upper arm about the pin cause rotation of the second wheel and the lower arm relative to the upper arm, resulting in a bending or straightening of the arm.

Abstract: A simulation method and a simulation system for a construction crane are disclosed. The simulation system includes an input device, a processing device, and a display device. The input device is used for inputting an instruction. Furthermore, the processing device includes a computation unit, a collision detection unit, a storage unit, and a graphic unit. The computation unit is used for computing the position and the direction of each part of the construction crane and the suspension parts. The collision detection model is used for detecting whether each part of the construction crane and the suspension parts will be in collision. Besides, the data obtained from the simulation method performed in the simulation system is saved in the storage unit. The graphic unit displays the 3D dynamics images of the construction crane and the suspension parts on the display device, corresponding to the data obtained from the computation unit.

Abstract: A transfer apparatus includes a stationary base, a lift base, a lifting mechanism for vertically moving the lift base, a rotary base mounted to the lift base, a rotating mechanism for rotating the rotary base about a vertical rotation axis, a linear moving mechanism supported by the rotary base, and a work hand supported by the linear moving mechanism. The lifting mechanism includes a slide guide mechanism for vertical movement of the lift base, and first and second screw-feeding mechanisms. Each screw-feeding mechanism includes a rotatable vertical screw shaft, and a nut member provided on the lift base and screwed onto the screw shaft. The first and the second screw-feeding mechanisms are spaced from each other, with the rotation axis of the rotary base being located between the first and the second screw-feeding mechanisms.

Abstract: A method of configuring a biomimetic mechanical joint for the efficient movement of a support member about a pivot device. The method includes providing a first fractional actuator and a second fractional actuator being operable with the support member and the pivot device, sizing the first fractional actuator for rated operation at a first boundary condition, and sizing the second fractional actuator so that the first and second fractional actuators, when recruited in combination, are rated for operation at a second boundary condition.

Abstract: A two degree-of-freedom positioning and manipulating apparatus is provided. The apparatus includes a first driven member rotatable about a first driven axis, a first driver member coupled to a first driven member for rotating the first driven member about the first driven axis, and a link member fixedly connected to the first driven member. The apparatus further includes a second driven member rotatably mounted to the link member for rotating about a second driven axis, with the second driven axis generally parallel to the first driven axis, and a second driver member coupled at a drive point to the second driven member for rotating the second driven member about the second driven axis. The drive point is generally coincident with the first driven axis.

Abstract: A method for operating a multi-axis, preferably six-axis, robot with axes that can be driven by drive means is proposed. The axes are possible to be moved separately and their movement is controlled by a control facility. Before the movement of the robot is executed, a control data record is created for controlling the movement of the robot as a function of initial and target information for the robot input by a user. The control facility performs a verification of the control data record in respect of at least one predefined basic condition relating to the operation of the robot stored in a memory. The control data record is adjusted based on the at least one basic condition whilst retaining the target information as a function of the result of the check.

Abstract: The invention relates to a device which is used to move and orient an object in space and to the use thereof in rapid machining. The inventive device (1) comprises an object support which is borne by an intermediary mobile support (13) which is connected to a fixed frame (2) using articulated connecting means (7a, 7b, 7c). The invention also comprises means for moving the aforementioned intermediary mobile support (13) in relation to the fixed frame (2), which maintain the orientation of said intermediary mobile support (13) in relation to the fixed frame (2). The invention further comprises a mechanism (14) which is used to orient the object support in relation to the intermediary mobile support (13). The above-mentioned means for moving the intermediary mobile support (13) comprise actuators (5a, 5b, 5c) which are used to move an end part of each of the articulated connecting means (7a, 7b, 7c) borne by the fixed frame (2) translationally.

Abstract: A humanoid traffic control robot is provided, which is installed on all or some of the lanes of a road where maintenance work, subway construction, or an unexpected situation such as a traffic accident takes place and allows arm parts of a robot body thereof to freely implement desired arm operations and thus to more easily perform a variety of traffic control signal services.

Abstract: A robotic wheelhouse hemming apparatus includes a base. A multi-axis robot is mounted on the base. The robot includes an arm. A roller hemming head is mounted on an end of the arm for roller hemming. A slide mechanism is mounted for multi-directional movement on the base. A support is mounted on the slide mechanism. An anvil is supported on the support. A registration member is integral with the support and is engagable by the roller hemming head. The robot arm is operable to manipulate the roller hemming head into engagement with the registration member, and subsequent movement of the robot arm moves the support on the slide mechanism, thereby adjusting the position of the anvil relative to a workpiece to be hemmed.

Abstract: The present invention relates to a method and a system for determining the relation between a local coordinate system located in the working range of an industrial robot (1) and a robot coordinate system. The method includes attaching a first calibration object (10) in a fixed relation to the robot and determining the position of the first calibration object in relation to the robot. Then, locating at least three second calibration objects (14,15,16) in the working range of the robot, a reference position for each of the second calibration objects in the local coordinate system can be determined by moving the robot until the first calibration object is in mechanical contact with each second calibration object. By reading the position of the robot when the calibration objects are in mechanical contact the relation between the local coordinate system and the robot coordinate system can be calculated.

Abstract: An ergonomic tool lifting machine and method particularly useful for manipulating a machine tool or another heavy object. In one embodiment of the invention, the machine tool is a large milling cutter. The ergonomic tool lifting machine generally includes an articulating arm attached at a fixed end to a vertical lift mechanism, and at a free end to a grasping device or tool holder adapted for gripping and retaining an object of interest. When the object is a milling cutter, the ergonomic tool lifting machine may be used to transfer the cutter between a stored position and an installed position in a milling machine. Consequently, the tool holder of this embodiment is preferably able to rotate between a pick-up/drop-off position and an installation/removal position associated with the cutter. In general, the ergonomic tool lift machine allows heavy loads to be accurately moved with very little effort required on the part of an operator.

Abstract: A robot arm assembly includes a first joint, a second joint and a flange. The second joint is rotatably connected to the first joint. The flange is fixed on the second joint. The first joint includes a rotary connecting portion located on an end of the first joint and a limiting portion adjacent to the rotary connecting portion. The flange defines a through hole in a middle portion of the flange and an open ring groove around the through hole. A curve of the open ring groove is less than 360°. The rotary connecting portion passes through and is received in the through hole. The limiting portion slides in the open ring groove.

Abstract: A surgical slave robot is disclosed. The surgical slave robot, for performing a surgical operation with a surgical instrument installed on an end portion of a robot arm, can include: a main body; a major support arm that is coupled to the main body such that the major support arm is movable along one direction; a minor support arm rotatably coupled to the major support arm; and a plurality of the robot arms rotatably coupled to the minor support arm. By coupling a twofold support arm of a major and minor support arm to a tower-shaped main body and coupling multiple robot arms to the support arms, the surgical slave robot may be constructed with a compact and slim size that occupies a small amount of space, making it possible to position the surgical robot close to the patient while providing space for the surgeon to access the patient.

Abstract: Provided is a substrate transfer apparatus which can perform stable and highly accurate transfer without making a configuration complicated. A substrate transfer apparatus according to the present invention includes a multijoint arm whose one end is arranged on a base and the other end is connected to a hand for supporting a substrate, a linear guide for guiding a rectilinear movement of the hand, and a belt driving mechanism for moving the hand along a guide rail of the linear guide. The substrate transfer apparatus having such a configuration supports a load acting on the hand by the multijoint arm and ensures rectilinear transfer performance of the hand by the linear guide. Therefore, since a special mechanism for passing the substrate through a dead point is not required, the configuration is prevented from becoming complicated. Furthermore, since the load does not directly act on the linear guide, high transfer accuracy can be obtained.

Abstract: A manipulator, such as for use in medical procedures, is provided. The manipulator includes a body and a first actuator system connected to the body at a first attachment point and capable of moving the first attachment point with at least three degrees of freedom. A second actuator system is connected to the body at a second attachment point and capable of moving the second attachment point with at least three degrees of freedom. A third actuator system is integrated with the body and is capable of moving at least a portion of the body with at least one degree of freedom.

Abstract: In a control method for a power assist apparatus, a pressing force acting on a workpiece held by a workpiece holding apparatus is detected, a determination is made as to whether or not the detected pressing force exceeds a preset threshold, a determination is made as to whether or not a dead man switch provided on the workpiece holding apparatus is ON, and a determination as to whether or not to release a rotation restriction applied to a joint portion for connecting the workpiece holding apparatus rotatably to an arm is made in accordance with a result of the determination as to whether or not the detected pressing force exceeds the preset threshold and a result of the determination as to whether or not the dead mean switch is ON.

Abstract: A parallel robot includes a base, a movable platform, a plurality of control arms, a rotation arm, a plurality of first actuators, and a second actuator. The control arms rotatably interconnect to the base and the movable platform, respectively. Opposite ends of the rotation arm are universally rotatably connected to the base and the movable platform, respectively. The first actuators move the control arms, respectively. The second actuator rotates the rotation arm around a central axis. Each control arm comprises a first transmission member and a transmission cable. The first transmission member comprises a fan-shaped transmission portion. Each first actuator comprises a transmission shaft to engage the first transmission member of the control arm. The transmission cable coils around the transmission shaft for at least one winding, then criss-crosses, and winds on the fan-shaped transmission portion.

Abstract: A transfer robot includes a hand section, a horizontal arm mechanism, and a lift mechanism. An object is to be placed on the hand section. The horizontal arm mechanism is connected to the hand section and includes at least two rotary joints. The horizontal arm mechanism is configured to extend and contract so as to move the hand section along one direction. The lift mechanism is configured to move the horizontal arm mechanism up and down and includes a plurality of link mechanisms disposed on a base member. The horizontal arm mechanism is disposed between parts of the lift mechanism when the horizontal arm mechanism is moved to a lowest position.

Abstract: A transfer apparatus includes a fixed base, a swivel, a lift mechanism for raising and lowering the swivel relative to the fixed base, a swivel mechanism for turning the swivel about a vertical swivel axis, a linear movement mechanism supported by the swivel, and a hand supported by the linear movement mechanism for transportation of a work along a linear horizontal travel stroke. The lift mechanism includes N (N is an integer equal to or greater than 2) lift members arranged for telescopic expansion and retraction relative to the fixed base. The lift mechanism also includes N lift drive mechanisms each for raising and lowering one of the lift members relative to an immediate lower-stage lift member. The swivel is supported by an uppermost one of the lift members. (FIG.