Abstract: An internal clamping and welding device for joining tubes by their distal ends, the device comprising movement means in order to be moved inside the tubes, separate clamping means for cooperating with the inner surfaces of the tubes to be welded, and a welding head mounted so as to be able to both rotate about a longitudinal axis of the tubes, and also pivot in order to be tiltable relative to a support of the clamping means.

Abstract: A jig device for laser welding of the disclosure includes a jig body having a semi-oval shaped seating groove in which a lower side of a refrigerant pipe to which a charging port is coupled is seated; a first pressing block provided in an upper portion of one side of the jig body and having a first groove part configured to press an upper portion of one side of the refrigerant pipe and an upper portion of one side of a fixing part of the charging port at a lower surface thereof; and a second pressing block provided at an upper portion of the other side of the jig body and having a second groove part configured to press an upper portion of the other side of the refrigerant pipe and an upper portion of the other side of the fixing part of the charging port at a lower surface thereof.

Abstract: A method for making a sink with a supporting structure including providing a sink including at least one basin and a rim extending outwardly from at least one side of the at least one basin, and coupling a support structure in the form of at least one channel to an underside of the at least one side of the rim using a tool. The tool includes a channel support configured to receive one channel of the at least one channels.

Abstract: A welding system includes power conversion circuitry configured to convert input power to weld power and a first housing surface. The first housing surface includes a first mating geometry configured to mate with a first complementary geometry of a first modular surface of a first modular component of the welding system.

Abstract: A welding tool includes a tool support and a welding torch coupled to the tool support. The welding tool is configured to rotate relative to the tool support about a welding axis. A locating device is coupled to the tool support and is movable between a retracted position and an extended position. In the extended position, the locating device extends toward the welding axis. The locating device includes a recess at an end of the locating device. The recess is configured such that, when a predetermined object to be welded (such as an anchor rod) is positioned at least partially within the recess of the locating device in the extended position, the welding axis passes through the object to be welded.

Abstract: A system for manufacturing boiler tubes includes a first spindle for receiving a first tube having a first weld preparation, a second spindle for receiving a second tube having a second weld preparation, the first spindle and the second spindle being rotatable synchronously, and a welding device having a first weld head. The welding device is configured to automatically weld the first tube to the second tube according to a control routine stored in memory to produce a boiler tube.

Abstract: Embodiments are directed to methods, systems, and apparatuses, for providing fittings capable of being orbitally welded. A system may include measuring components configured to measure a tubing thickness and measure a fitting thickness. The system may also include a processor configured to determine a difference in thickness between the measured tubing thickness and the measured fitting thickness and, based on the determined difference in thickness, determine an amount of fitting that is to be removed to reach a set, specified thickness that allows the fitting to be orbitally welded. The system may also include a facing tool configured to bevel and shape an end portion of the fitting according to the determined amount of fitting that is to be removed to reach the specified thickness and may include an orbital welder configured to orbitally weld the beveled end of the fitting to the tubing in a fusion socket weld.

Abstract: A system for welding two pipes includes a first pipe clamp, a second pipe clamp, a weld torch, an inspection detector, a motor, one or more processors, and a grinder. The weld torch is configured to create a weld joint between the pipes at an interface region between the pipes. The inspection detector is configured to emit an inspection beam of radiation. The motor is operatively associated with the inspection detector to direct the inspection beam of radiation along the weld joint between the pipes. The one or more processors are operatively associated with the inspection detector to determine a profile of the weld joint between the pipes. The grinder is configured to grind at least a portion of the weld joint between the pipes based on the profile of the weld joint between the pipes.

Abstract: The current invention is regarding an electrical slip ring system for high speed applications, which require slip rings to operate at speeds more than 60,000 RPM. It consists of multiple single stage slip rings and multiple gear devices, where all the stators, except the last one, are rotational. The speed limit on the slip ring market, by using the advanced fiber brush bundles, is about 10,000 RPM without cooling, or lubricating. The basic idea is that by designing gears, we can always can make sure the relative speed between the rotor and the stator in each stage is <=10000 rpm.

Abstract: A welding tool includes a tool support and a welding torch coupled to the tool support. The welding tool is configured to rotate relative to the tool support about a welding axis. A locating device is coupled to the tool support and is movable between a retracted position and an extended position. In the extended position, the locating device extends toward the welding axis. The locating device includes a recess at an end of the locating device. The recess is configured such that, when a predetermined object to be welded (such as an anchor rod) is positioned at least partially within the recess of the locating device in the extended position, the welding axis passes through the object to be welded.

Abstract: A welding device according to some embodiments includes a rotary table fixing two irregular shaped plates which are overlapped, a torch unit including a welding torch positioned to face outer peripheral edges of the two irregular shaped plates fixed to the rotary table, a torch actuator configured to move the welding torch toward and away from the outer peripheral edges, an after-shielding part mounted to the welding torch on downstream side in a rotational direction of the rotary table and having nozzles arranged along the rotational direction, configured to jet shielding gas to the outer peripheral edges, and including a first nozzle positioned upstream and a second nozzle positioned downstream of the first nozzle in the rotational direction, and a controller configured to control an orientation of the nozzle in a direction of decreasing a shielding-gas-jetting distance between the second nozzle and the outer peripheral edges welded by the welding torch.

Abstract: Welding systems including a hydraulically driven welding power supply adapted to utilize hydraulic primary power to generate a first welding output for a first welding operation and a second welding output for a second welding operation are provided. Such welding systems may include control circuitry coupled to the hydraulically driven welding power supply and adapted to enable the hydraulically driven welding power supply to provide the first welding output and the second welding output at the same time to enable a first welding operator and a second welding operator to perform the first welding operation and the second welding operation, respectively, at the same time.

Abstract: A work table support device capable of adapting to a plurality of applications. The workpiece support device includes a base; a conductive work table rotatably supported on the base; a current-collecting brush that is fixed to the base, slidably contacts an end face of the work table, and supplies electric power to work table, and a cover that is removably attached to the base, surrounds the current-collecting brush and the end face, and includes cover segments that can be assembled and disassembled one another.

Abstract: Provided is a laser welding method for flat wires in which side surfaces at ends of first and second flat wires coated with insulating films, the side surfaces being stripped of the insulating films, are butted together, and a laser beam is applied to end surfaces of the first and second flat wires to weld together the side surfaces. This method includes: applying the laser beam in a loop shape inside the end surface of the first flat wire to form a molten pool; and gradually increasing the diameter of a loop-shaped application trajectory of the laser beam inside the end surface of the first flat wire to allow the molten pool to reach the side surfaces.

Abstract: A method for generating a weld path aligned along a seam between two parts uses a computer having a control unit and a storage medium. The method includes aligning a crosshair line at a plurality of points along the seam and storing a position value for each of the plurality of points in the storage medium; calculating a width and a height of the seam based on the stored position values of each of the plurality of points; and generating the weld path based on the height and the width of the seam.

Abstract: A personal electronic device is adapted to construct data tables from user input received over time relating to translations of translatable items from a first language to a second language. Entries in a data table for a user are dynamic and may indicate likelihoods of the user correctly translating translatable items as a function of time. Each translatable item may have a different time-dependent likelihood of a correct translation. Operation of the personal electronic device for a user may be based in part on the acquired, time-dependent likelihoods for that user, so that information may be presented to the user in a more efficient manner.

Abstract: Generating a robot control policy that regulates both motion control and interaction with an environment and/or includes a learned potential function and/or dissipative field. Some implementations relate to resampling temporally distributed data points to generate spatially distributed data points, and generating the control policy using the spatially distributed data points. Some implementations additionally or alternatively relate to automatically determining a potential gradient for data points, and generating the control policy using the automatically determined potential gradient. Some implementations additionally or alternatively relate to determining and assigning a prior weight to each of the data points of multiple groups, and generating the control policy using the weights.

Abstract: An electro-anti deposit device is coupled to an irrigation pipe for removing mineral deposit from drippers of the pipe. The electro-anti deposit device includes an engine configured to move the electro-anti deposit device along the pipe. The electro-anti deposit device also includes a mineral deposit removal module. The mineral deposit removal module includes a water container, a battery, and two electrodes. The water container may be configured to create an ionic environment at a dripper. The dripper may be covered with the mineral deposit. The battery may be configured to generate electric current. The two electrodes may be connected to two poles of the battery with a space separating tips of the two electrodes.

Abstract: A rotating electric machine having downsized coil ends is provided. In a rotating electric machine having a stator 130 including a stator core 132 formed with a plurality of slots 420 rowed in a circumferential direction and a stator coil 138 inserted into the slots of the stator core, and a rotor 150 disposed rotatably with respect to the stator core with a clearance interposed therebetween. The stator coil is formed by a plurality of segment coils 28 being connected, the segment coils 28 being made of a conductor shaped into a rough U-shape and having a rectangular cross-section. The segment coil has at an end a connection portion 800 connected to another segment coil, the connection portion having a corner portion 810.

Abstract: Orbital welding device including a body, a welding head carried by one end of the body, and a device for holding the body on a tubular element to be welded, including: cantilever portions of the end of the body, which project in an overhanging manner transversely to a rotation axis of the welding head and beyond the rotation axis; a plurality of through holes formed through the cantilever portions transversally to these portions and to the rotation axis, positioned axially to the side of the welding head; a plurality of pneumatic devices accommodated in the through holes so that each device can selectively extract and lock in an extracted position toward the rotation axis a respective pin adapted to interact with the element to be welded; a pair of manifolds fixed in a laterally removable manner on the outside of the cantilever portions and in hydraulic communication with the through holes and compressed air supply conduits connected to a control box provided with an electrovalve controlled by a manually oper

Abstract: A method of welding a pipe section in a ring-based welding system, wherein the welding system comprises: (i) an adjustable ring gear mount; (ii) a ring gear assembly positioned on the adjustable ring gear mount, the ring gear assembly having an inner diameter and a center point; and (iii) at least one weld head assembly mounted on the ring gear assembly.

Abstract: The invention relates to a method for welding rotors for power generation such as gas turbines, steam turbines, and generators having a plurality of rotor discs arranged along a rotor axis. The method includes providing said discs with a weld seam preparation. The weld seam preparation includes a root, a first, gap-like welding section adjoining the root in radial direction, and a second, gap-like welding section adjoining the first welding section in radial direction. The method further includes melting the root by means of a first welding process; making a weld in the first welding section by means of a second welding process; and filling up the second welding section by means of a third welding process.

Abstract: A method of controlling a spot welding system used for attaching an inserted element in a hollow member is provided. A position of the inserted element in the hollow member is determined, the position of an attachment point is determined from the position of the inserted element in the hollow member, and a spot welding operation is performed at the attachment point. Further, a spot welding system for carrying out the method is provided.

Abstract: A method for programming an industrial robot includes moving a manipulator arm of the industrial robot manually (hand guided) into at least one pose in which at least one control variable, which is to be entered in a robot program, is recorded by a control device of the industrial robot and is saved as a parameter of an associated program instruction in the robot program. In another aspect, an industrial robot includes a robot control unit which is designed and/or configured to carry out such a method.

Abstract: One embodiment of the present invention relates to a system for buried-arc welding with thru-the-arc seam tracking. Another embodiment of the present invention relates to a method for buried-arc welding with thru-the-arc seam tracking.

Abstract: A method of welding a plurality of conductors to form a winding extending through an annular stator core. The conductors are inserted into slots formed in the stator core to have coil ends extending outside an end surface of the stator core. A plurality of pairs of the coil ends are arranged in diagonal arrays extending diagonally with respect to a radial direction of the stator core. The method inserts a first electrode into a gap between adjacent two of the diagonal arrays and then brings a second electrode close to one of the adjacent two of the diagonal arrays to arc-weld the pairs of the coil ends. This welding method enables the welding of the coil ends arrayed in the above layout efficiently while keeping the electrical insulation between the pairs of the coil ends.

Abstract: A method and apparatus for multi process welding includes providing a controlled short circuit output and a pulse output in response to a user selection across a workpiece output stud and a torch output stud.

Abstract: A welding bug (1) comprising a welding torch (3) for welding in a groove (19). The welding torch (3) is mounted for rotational movement about an axis (21) that is substantially horizontal, relative to the welding bug, (typically tangential to a pipe during use) so that the torch is moveable, during use of the welding bug (1) when arranged to enable the torch to weld in a groove, between (i) an operating position, and (ii) a disengaged position in which the welding torch is positioned away from the groove (19). The welding bug may be less cumbersome and more compact than some known arrangements.

Abstract: A first embodiment of the present application is directed to a method and system used to weld a cylindrical workpiece. A substantially cylindrical workpiece is loaded into a workpiece support, and a robotic welding arm is positioned located at a start position. A value representing a size of the cylindrical workpiece is input into a robot controller via a system interface. Inputting of the size value to the robotic interface obtains a control program. Operation of the obtained control program is initiated by an operator, causing the robot arm to move a preprogrammed distance toward a work surface of the workpiece. Then a welding process is performed by the welder carried on the robot arm in accordance with the control program. The process includes initiating operation of the welder, and moving the welder in a pattern appropriate for the welding operation. The workpiece and welder are moved relative to each other so as to perform the welding process as determined by the control program.

Abstract: Guide device for use in the processing, in particular welding, of curved surfaces, in particular pipe surfaces. A guide device includes a flexible elongate body provided with a guide for processing means and a tensioning means for tensioning the flexible body around the curved surface. The flexible body is provided along its length with indicators arranged according to a determined pattern, this pattern being such that a determined position of the guide device along the flexible body can be inferred on the basis of the detection of the indicators.

Abstract: A tractor unit mounting mechanism includes a clamping assembly that is configured to engage and disengage a tractor unit to a guide track. The guide track includes a first rail and a second rail. The mounting assembly also includes at least one pivot block set that has a first pivot block and a second pivot block. Each of the first pivot block and the second pivot block includes a first rolling device and a second rolling device. When the tractor unit is in a disengaged position, a first distance between an outer portion of the first rail and an outer portion of the second rail is greater than a second distance between the first rolling devices of the at least one pivot block set, and the first distance is less than a third distance between the second rolling devices of the at least one pivot block set.

Abstract: In a method for joining two, in particular rotationally symmetrical, metal parts (1, 2) by a tungsten inert gas (TIG) welding process, in a first step, the two metal parts (1, 2) to be joined are initially positioned relative to one another by a centering offset (7) in such a way that a narrow gap (4) is formed between them and a relief region (8) is created in the seam-bottom area. In a second step, the flanks (5, 6) of the metal parts (1, 2), which delimit the narrow gap (4), are joined together by welding beads (10) which fill the narrow gap (4), with a predetermined melt-through point (9) being formed. High-quality automatic welding is achieved in that the narrow gap (4) has a continuously constant width (a), in that the width (a) of the narrow gap (4) is selected such that the welding beads (10) lying one above the other each extend over the entire width (a) of the narrow gap (4), and in that the entire narrow gap (4) is filled with the welding beads (10) in fully automatic fashion.

Abstract: The invention relates to a ground peg (10) which is made from a steel tube (11) and comprises an upper cylindrical section (12), a lower section (16) that tapers towards the bottom to form a tip (14), and an external thread (26) that extends along at least part of the lower section (16) and is formed from a continuous sheet metal strip (28) welded onto an external surface (32) of the ground peg (10) by means of a continuous or regularly interrupted fillet weld (34). The external thread (26) has a nearly constant pitch (S) and slope (a) relative to a longitudinal axis (40) of the ground peg (10) along the entire length of the external thread (26). The invention further relates to a method or producing such a ground peg (10).

Abstract: Method in which a continuous butt-sealed rim of a collar defined by corresponding concentric ends, without undulations, of a first wall, radially innermost, and a second wall, radially outermost, of a double-wall bellows is obtained as a continuous butt-weld bead on the corresponding rims, arranged radially adjacent to each other, of the ends of the first and second walls, which have been prepared such that, before welding, they are radially spaced apart from each other by not more than 0.3 mm and with the rim of the second wall that projects in an axial direction with respect to that of the first wall for a length of 0.2-0.4 mm; butt welding is performed with a laser beam directed parallel to an axis of symmetry of the collar, making the latter rotate around the axis to progressively expose the entire perimeter of the rims of the ends of the first and second walls, simultaneously pressing the rims against each other with a force between 1 and 3 kg via spring clamping rollers.

Abstract: A bore welding mechanism comprising a casing having spindle bushings rotationally and axially supporting a rotatable and axially translatable spindle for supporting a bore repair mechanism in alignment with a bore. The spindle has an axially extending keyway and a worm gear thread extending for at least a part of a length of the spindle. A spindle drive gear is coupled to the spindle by a drive key engaging with the keyway of the spindle so that the spindle is rotationally fixed to the spindle drive gear and axially translatable with respect to the spindle drive gear. A drive shaft extends through the casing, transversely to and offset from an axis of the spindle, and includes a drive shaft worm gear rotationally fixed to the drive shaft. The worm gear engages with the spindle drive gear to rotate the spindle drive gear and the spindle due to rotation of the drive shaft.

Abstract: A level entry bore welder that is easier to use and less expensive to purchase. It has an adjustable step feature that allows the operator to control the bead placement inside the bore of a work piece. It includes a simple remote control apparatus that adjusts the welding torch rotation speed as a function of the diameter of the bore. The remote control apparatus also permits the operator to turn the wire feed mechanism on and off. The welder is suited for bores up to 12 inches in diameter.

Abstract: A weld zone of T-piping and its neighborhood are efficiently laser-heated to remove residual stress. For this purpose, the weld zone of a T-piping (50) is irradiated and heated with a laser beam emitted from a laser head (10) to remove residual stress. At this time, a rotating travel cart (3) travels along a ring rail (2) to adjust the position of the laser head (10) in a ?-direction, a vertical slide (4) slides to adjust the position of the laser head (10) in a Z-direction, a radial slide (5) slides to adjust the position of the laser head (10) in an L-direction, an arcuate piece slide (7) slides along an arcuate piece to adjust the ?-direction of the laser head (10), a laser head support portion (9) turns to adjust the ?-direction of the laser head (10), and oscillation adjusts the position of the laser head (10) in a ?-direction.

Abstract: An industrial robot has a base for installation, a first arm, a second arm, a third arm, a wire feeder, a welding torch, and a torch cable. The first arm rotates with respect to the base. The second arm pivots with respect to the first arm. The third arm pivots with respect to the second arm. The torch cable is coupled to the wire feeder and feeds a welding wire to a welding torch. The wire feeder is provided to the second arm and is rotatable around a rotation axis.

Abstract: A method and a device produce a fleece of metallic fibers in a layer in which the metallic fibers are welded to one another to form the fleece. A welding process is repeatedly carried out with regard to a portion or section of the fleece. Such metallic fiber fleeces are used, in particular, for exhaust gas treatment units in the automobile industry.

Abstract: In a method, a first electrode is moved to contact with first paired ends of first paired conductor segments. Next, a second electrode is moved opposing the first paired ends Electric conduction is established between the first electrode and the second electrode via the first paired ends of the first paired conductor segments to weld the first paired ends of the first paired conductor segments based on the electrical conduction therebetween. Next, the second electrode is moved opposing second paired ends of second paired conductor segments while the first electrode is kept in contact with the first paired ends. Electric conduction is established between the first electrode and the second electrode via the welded first paired ends and the second paired ends to thereby weld the second paired ends of the second paired conductor segments based on the electrical conduction therebetween.

Abstract: A purge gas introduction system for an orbital tube welding setup is provided, configured to inject high purity inert purge gas to the interior volume of a tube or tubular component. An o-ring is interposed between an annular base and an annular ring, their junction forming an annular o-ring groove, each part forming one sidewall, with the o-ring fully recessed within the groove, protecting the o-ring during the insertion and removal of a tube. The annular base and an annular ring are configured to receive a tube terminus. The sidewalls of the o-ring groove are divergent one to the other, wherein as the annular ring is drawn towards the annular base, the o-ring is forced partially out of the groove, forming a substantially leak tight seal between the tube and the o-ring. A purge gas from an external source is transmitted to the annular base through a purge connector, then, in turn, introduced to the interior volume of the tube.

Abstract: A method for controlling a robot during an interpolation of a trajectory or motion to any prescribed position, comprises the steps of a) ignoring at least one of the three originally prescribed or interpolated tool center point orientation values; b) finding new tool center point orientation values that place the wrist center point of the robot closest to its base while c) maintaining the originally prescribed or interpolated tool center point location values and d) maintaining the original prescribed or interpolated tool center point orientation values not ignored. Said method can preferably be used for carrying a load with a plurality of robots. Its main advantage is an increase of the available working volume.

Abstract: An orbital weld head includes a metal insert and rotor. The covers are made from mica laminate. A metal spring/brush that is preferably one piece side loads the rotor against the insert. The rotor and insert have interengaging portions, preferably trapezoidal, that cause the rotor to move axially when it expands from heat, thus minimizing binding.

Abstract: In a method, a first electrode is moved to contact with first paired ends of first paired conductor segments. Next, a second electrode is moved opposing the first paired ends Electric conduction is established between the first electrode and the second electrode via the first paired ends of the first paired conductor segments to weld the first paired ends of the first paired conductor segments based on the electrical conduction therebetween. Next, the second electrode is moved opposing second paired ends of second paired conductor segments while the first electrode is kept in contact with the first paired ends. Electric conduction is established between the first electrode and the second electrode via the welded first paired ends and the second paired ends to thereby weld the second paired ends of the second paired conductor segments based on the electrical conduction therebetween.

Abstract: An apparatus and/or process for applying a weld overlay to a nozzle or piping spool of complex configuration is disclosed. In an exemplary embodiment, the welding apparatus comprises a mounting assembly having a plurality of magnetic foot pads, a tension support rod attached at one end to one of the magnetic foot pads, an upper attachment pad at the opposite end of the rod, and a bottom attachment pad attached to at least one other magnetic foot pad; a travel guide, the travel guide attached to the upper attachment pad at one end and the bottom attachment pad at the other end; and a head assembly attached to the travel guide, the head assembly having: i) a track ring assembly having an inner ring and an outer ring, ii.) at least two opposed weld heads attached to the inner track ring, iii.) at least one movable wire feed drive mechanism on the track ring, and iv.

Abstract: An operation control unit of a reception system includes a visitor ID information DB for storing therein visitor comparison information and visitor ID information including a phone number of a receiver of a visitor; an identifying unit for identifying the visitor when visitor information obtained by a camera or the like of the robot is identical to the visitor comparison information; a phone calling module for calling the phone number of a mobile terminal of the receiver via a phone network, when the visitor is identified; an informing content determining unit for determining an informing content to the receiver based on the visitor ID information, when the visitor is identified; and a speech generating part for converting the received information into a voice. The informing content is sent to the mobile terminal of the receiver via the phone network.

Abstract: When braking of a motion of a part of a first robot is assumed to be started at points in time, a first stop position of the first robot part is estimated at each point in time. When braking of a motion of a part of a second robot is assumed to be started at the points in time, an estimated second stop position of the second robot part is obtained at each point in time. When it is determined that the first stop position of the first robot part at one of the points in time and either the actual position or the second stop position of the second robot part for each interval at the one of the points in time are contained in the shared workspace, the first robot part is braked.

Abstract: Welding material is deposited automatically in the annular facing. A welding torch is causes to rotate about an axis of rotation that extends in a direction that is radial relative to the spherical wall and that passes through a point of the concave inside surface of the spherical wall in the central portion of the annular facing. Simultaneously with the welding torch being caused to rotate about the axis of rotation, it is displaced in a direction perpendicular to the axis of rotation in controlled manner, and the position of the welding torch in a direction parallel to the of rotation is also controlled so that the electrode of the welding torch describes an elliptical path and ensures that the welding material is deposited in the annular facing in the form of an elliptical bead.

Abstract: A flexible articulate tubular device has a shank, a plurality of pivot rings, and a terminus with heat sensors and a fiber optic device. The flexible articulate tubular device is initially positioned, either manually or automatically, near a target weld path with the aid of the fiber optic device. The flexible articulate tubular device is then more precisely articulated to direct the terminus along the target weld path, with the aid of the heat sensors. As such, the flexible articulate tubular device operates in a heat seeking manner to follow the weld bead. Ultimately, a gaseous flux is supplied along the flexible articulate tubular device and toward the target weld path, so as to blast the weld bead with an anti-oxidation shield gas and thereby protect the weld.

Abstract: A welding head which can easily move the torch portion of the welding head in the circumferential direction and the vertical moving direction of the outer circumference of the to-be-welded tubes even in a narrow gap, includes a torch rotating ring that rotates on the outer circumferences of the tubes by matching with the central axis of the to-be-welded tubes and a torch vertical moving ring disposed concentrically with the ring inside the ring, provided with a torch base for supporting a torch on the front ends, a first gear group for driving and rotating the ring around the tubes, a second gear group that is disposed in parallel to the first gear group and drives and rotates the ring around the tubes, a drive shaft for driving the two gear groups, and a torch rotating motor for driving the drive shaft, and a third gear group that can drive the ring while rotating it in the same direction as or in reverse to that of the ring at a speed equal to or higher or lower than that of the first gear group for rotatin