Abstract: The present invention provides a producing method of a rare earth sintered magnet which is suitable as a producing method of a high performance rare earth sintered magnet which can reduce the number of steps for reusing defective molded bodies generated in a wet molding step of the rare earth sintered magnet, and which has a small content amount of oxygen. The invention also provides a slurry recycling method used for the producing method, and a slurry recycling apparatus. Each of the methods includes a crushing step of crushing, in mineral oil and/or synthetic fluid, a molded body in which slurry formed from alloy powder for a rare earth sintered magnet and mineral oil and/or synthetic fluid is wet molded in magnetic field, and recycling the crushed molded body into slurry.

Abstract: A metal particle manufacturing system includes: a first airtight container, in which a metal film is placed and conveyed; a plasma melting chamber for heating and melting the metal film into ultrafine particle metal; a second airtight container for cooling and suspending the ultrafine particle metal for collection and being taken out; and a circulating conveyor belt for providing conveying channels between the first airtight container, the plasma melting chamber and the second airtight container. Airtight channels are provided to cover between the first airtight container, the plasma melting chamber and the second airtight container. With this implementation, the highly pure ultrafine particle metal with the purity reaching 99.99% can be obtained.

Abstract: A device for connecting two components (10, 14), for example two tool parts. The first component (10) has a cylindrical locating pin (12) and an annular face (22) projecting radially beyond this locating pin (12), while the second component (14) has a cylindrical locating bore (16) for receiving the locating pin (12) and an annular face (24) surrounding the locating bore (16). Also provided is a clamping mechanism (18), which ensures during the clamping operation that the locating pin (12) is drawn into the locating bore (16) and at the same time the annular faces (22, 24) are pressed against one another.

Abstract: A chuck for use with a driver having a rotatable drive shaft, the chuck including a body having a nose section and a tail section, the tail section being configured to rotate with the drive shaft and the nose section having an axial bore. A plurality of jaws is movably disposed with respect to the body and in communication with the axial bore. A first sleeve is rotatably mounted to the body in operative communication with the jaws so that rotation of the sleeve moves the jaws either toward a longitudinal center axis of the axial bore or away from the longitudinal center axis. A second sleeve is rotatably mounted to the body and is movable between a first position in which the second sleeve is rotatably fixed to the body and a second position in which the second sleeve is rotatable about the body. The second sleeve moves in a direction transverse to the longitudinal center axis of the axial bore when moving between the first position and the second position.

Abstract: A method is provided for implementing reduction of drill smear in drilling a multilayer substrate such as a rigid printed circuit board or flex to minimize or eliminate the need to remove drill smear and for improved via and interconnect reliability. An inert liquid is applied to the multilayer substrate and a drill bit prior to and during the drill process to cool and lubricate the multilayer substrate and the drill bit to reduce drill smear.

Abstract: A hole cutter has a substantially cylindrical blade body defining a blade body circumference, a cutting edge formed on one end of the blade body, and an axially-elongated slot formed through the substantially cylindrical blade body. The axially-elongated slot is configured to receive chips flowing from the cutting edge within the interior of the blade body and (i) into the slot, and/or (ii) through the slot, to prevent the collection of such chips within the interior of the blade body and/or at an interface between the blade body and work piece. The axially-elongated slot defines a first end adjacent to the cutting edge, a second end axially spaced further from the cutting edge, and a slot area. The hole cutter further defines a total slot area to blade body circumference ratio within the range of about 0.1 to about 0.3 depending on the size of the hole cutter.

Abstract: A guide gib (500) for a deep drilling tool of a substantially rectangular shape with a longitudinal direction (L) and a width (B) and with at least one sliding surface (540) is characterized in that at least one lubricating groove, preferably a plurality of lubricating grooves (501, 502), is/are arranged at least in the region of a contact zone of the sliding surface.

Abstract: A milling tool for the milling of a slot in a workpiece includes a plurality of cutting inserts, which comprise an under side; an opposite upper side, which forms a chip surface and extends parallel to an extension plane; and an edge side between the upper side and the underside. A cutting edge, which extends between the edge side and the chip surface, includes a primary main cutting edge; a front cutting edge, which extends along an edge line; and a primary corner cutting edge, which extends between and connects the primary main cutting edge and the front cutting edge. The primary corner cutting edge has a convex shape and extends, with respect to a rear portion of the cutting insert, forward from the front cutting edge to a position on the other side of an imaginary line, which forms an extension of the edge line and extends in a tangential direction to a point on the primary corner cutting edge.

Abstract: A single-sided ramping milling insert for ramping operations has top and bottom surfaces and a peripheral surface which extends therebetween. The peripheral surface meets the top and bottom surfaces at respective top and bottom edges. The top edge includes two opposite side cutting edges, two opposite ramping cutting edges, two diagonally opposite raised corner cutting edges and two diagonally opposite associated lowered corner cutting edges. The lowered corner cutting edges are closer to the bottom surface than the raised corner cutting edges. The bottom edge has two diagonally opposite bottom corner edges. The lowered corner cutting edges and the bottom corner edges are convexly curved and a depression is recessed into the peripheral surface between each lowered corner cutting edge and its associated bottom corner edge, the depression configured for providing relief from a convex workpiece surface cut by the lowered corner cutting edge during ramping operations.

Abstract: A material removal system enabling the installation of electrical outlet boxes and junction boxes among others, includes a platen for attaching to a vibrating movement, a blade with teeth having any circular or non-circular cutting edge which attaches to the platen that vibrates the teeth multidirectionally. The system enables rapid material removal and produces a clean rectangular aperture requiring little or no modification prior to installing an outlet box.

Abstract: For a machine tool designed in particular as a saber saw, a configuration including a carrying frame is provided, via which the lifting rod and the support element are joined to form a unit that can be rotated about the longitudinal axis of the power tool, is mounted on the casing side, and guides a drive part of the lift drive on the lifting rod side.

Abstract: A hack saw comprises a proximal end, a proximal handle located at the proximal end, and a distal end spaced from the proximal handle for mounting a hack saw blade therebetween. The handle includes a proximal cavity at a base end thereof, dimensioned to allow a portion of a proximal pin holder therethrough, and a proximal pin holder retaining member within the proximal handle proximally spaced from the proximal cavity, defining a slot therebetween for retention of a pin holder therein. The pin holder retaining member is positioned to form an interference with the proximal pin holder when the pin holder is located in the handle and prevents the proximal pin holder from dislodging or being removed therefrom.

Abstract: A process for producing a tool having a main body which extends in a longitudinal direction and at least one blade for machining a workpiece includes providing a base coating on the tool; grinding the at least one blade in a manner that removes the base coating in the region of the at least one blade; and providing a second, fine coating, to the at least one ground blade.

Abstract: In a method for machining a workpiece, an end face gearing is created on the end face of the workpiece by hob peeling. The workpiece is rotated about the Z axis in relation to a coordinate system with X, Y and Z axes arranged perpendicularly to one another. During creation of the end face gearing, the feed direction of the hob peeling tool encloses with the axis of rotation of the hob peeling tool an angle which is greater than 0° and less than 35°. The hob peeling tool is arranged in the X-Z plane at an angle to the X axis which is greater than 0° and less than 20°.

Abstract: A multi-pass gas metal arc weld (“GMAW”) approach is used for in-situ repair of railhead defects. A defect is removed via machining a perpendicular slot or grove in the railhead leaving the web and base unaltered. A sufficient number of GMAW passes are used to fill the slot using a weld material suitable for the particular type of parent steel, and excess weldment can be removed. Optionally, for pearlitic steel rails post-weld heat treatment can be used to cause austenization and/or quenching of the weld. The weld heat inputs and other parameters are controlled to avoid ductile and brittle fracture related morphologies.

Abstract: A tungsten submerged arc welding process wherein a non-consumable electrode (18) provides an arc (16) under a protective bed of flux powder (26), thereby eliminating the need for an inert cover gas supply. The arc melts a feed material in the form of alloy powder (22) or filler wire (40) along with a surface of a substrate (12) to form a layer of cladding material (10, 32) covered by a layer of slag (20, 44). The flux and slag function to shape the deposit, to control cooling, to scavenge contaminants and to shield the deposit from reaction with air, thereby facilitating the deposit of previously unweldable superalloy materials.

Abstract: Device for removing an electrode from an electrode holder and/or fitting an electrode into an electrode holder, said electrode holder forming part of a welding device, said device comprising a spent electrode receptacle provided with an orifice and an assembly mounted on said orifice, said assembly comprising a through passage with a longitudinal axis connecting a housing to hold one end of the electrode holder forming a mandrel, and the receptacle, said longitudinal axis being designed to be approximately vertical, means of tightening or loosening an electrode holder mandrel, means of fixing the electrode to said device and means of enabling or disabling dropping of the spent electrode into the receptacle.

Abstract: Internal coarse particle injection plasma transferred arc torch nozzles comprising: a heat-resistant nozzle body; at least one coarse hard-metal particle internal injection port; at least one fine hard-metal particle and matrix internal injection port; at least one gas port; and a cathode. Related systems, apparatus, compositions, and methods involving such arc torch nozzles are also disclosed.

Abstract: A weld splatter containment device for use in rolling mills includes a lower cover and an upper cover, both controllable in approaching and moving away from a welding zone so as to substantially surround the welding zone when the lower and upper covers are situated in a position close to the welding zone. The lower cover is controlled in approaching and moving away from the welding zone along a first circular trajectory portion and the upper cover is controlled in approaching and moving away from the welding zone along a second circular trajectory portion.

Abstract: The invention relates to an ultrasonic welding device having an oscillator, having a sonotrode, which can be caused to oscillate with a wavelength, and has a welding region in the vibration antinode of the sonotrode. The sonotrode is supported at the vibration node of the sonotrode in a first bearing. To enable both a radial and an axial alignment of the sonotrode, the first bearing has a projection, which has a U-shaped geometry in a section extending in a longitudinal direction of the sonotrode, which U-shaped geometry has side legs and a cross leg that connects the side legs, the projection engages in a recess in the sonotrode matched to the U-shaped geometry, the sonotrode is supported on the cross leg of the projection in a planar manner, and the sonotrode is axially aligned by means of at least one side leg of the projection.

Abstract: A friction stir welding apparatus has a probe rotatable and vertically movable with respect to a processing target member, a welding tool having an interposed member that covers a part of an outer periphery of the probe and is rotatable relative to the probe, a mounting member on which the processing target member is mounted, a movement mechanism having an arm fitted with the welding tool that can move the welding tool with respect to the processing target member by moving the arm, and a correction mechanism having a correction member that can correct a moving direction of the welding tool so as to be matched with a predetermined processing direction, by bringing the interposed member into contact with the processing target member when the welding tool is moved with respect to the processing target member by moving the arm, and fixed to the mounting member.

Abstract: A method of progressing a melt front (55) around a curved progression path (20) via a pattern (LP) of transverse laser scan lines (S1-S8) of differing lengths. Multiple area bands (B1-B8) conceptually divide a width of the curved path. The multiple transverse scan lines distribute the laser power among the bands with a predetermined uniformity that provides relatively consistent power density across the melt front. The scan lines may extend from a less curved side (24) of the curved path, through a band (B4 or B8) of largest area, toward a more curved side (22) of the path. At least one of the scan lines (S1, S8) may cross all bands. Other scan lines are shorter and extend by varying distances into the inner bands (B1-B3 or B1-B7), normalizing the power density across the bands.

Abstract: A laser processing machine for processing workpieces includes a beam guide containing a gas atmosphere, and also includes an apparatus for investigating the gas atmosphere in the beam guide for impurities. The investigation apparatus makes use of the photoacoustic effect. The measuring apparatus has a measuring chamber and at least one measuring head, where the beam guide acts as the measuring chamber. As a measuring chamber, the beam guide contains the gas atmosphere that is to be investigated and also a modulated laser beam modulated. The measuring head(s) are integrated into the beam guide and are used to detect the photoacoustic effect in the measuring chamber.

Abstract: The spot shape of a laser beam is detected by moving a table holding a detection substrate having a luminescent substance in an X direction and a Y direction with a laser beam focused by a lens applied to an area of the detection substrate where the luminescent substance is located. The intensity of light emitted from the luminescent substance is detected during the movement of the table, and a light intensity map is prepared indicating the light intensities detected in the light intensity detecting step at all of the X and Y coordinates of the luminescent substance. Spot shape images of the laser beam are formed according to a plurality of light intensity maps obtained by positioning the focusing lens at a plurality of detection positions changed in a Z direction perpendicular to a holding surface of the table.

Abstract: A movable vacuum welding device (1) includes a vacuum chamber (7) having an edge section (12) opposite to a surface of a welding target (T) and forming a vacuum space between the surface of the welding target (T) and the vacuum chamber (7), a seal section (8) interposed between the edge section (12) and the welding target (T) throughout the entire circumference of the edge section (12), a welding head (9) configured to perform welding on the surface of the welding target (T) in the vacuum space, and a preload unit (10) configured to previously apply a load to the seal section (8). The seal section (8) includes a first seal member (27) formed of an elastic material and extending along the edge section (12), and a second seal member (28) disposed at least a rear side in a relative moving direction in which a welding bead (W) passes and having higher flexibility than the first seal member (27).

Abstract: This specification describes connectors for tubes, pipes and poles, such as can be used in laser marking systems. In one aspect, an apparatus includes a body having a hole formed to receive a tube to connect an interior of the tube with an interior of the body, the tube having a circular groove formed in an exterior surface of the tube; and a clamp including a tab sized to fit within the circular groove of the tube; wherein the clamp is configured and arranged to attach to the body in a first state and in a second state, the first state being where the tube is held to the body axially by the tab and is freely rotatable, and the second state being where the tube is held in a fixed position relative to the body.

Abstract: A laser cutting device for cutting an original product includes a laser device which is movable along a first direction and a second direction perpendicular to the first direction, and rotatable reflecting mirrors. The original product includes a stub bar, optical lenses, and connection portions corresponding to the optical lenses. The rotatable reflecting mirrors correspond to the connection portions and are positioned above the original product and aligned with the connection portions. At least two rotatable reflecting mirrors are arranged in a straight line. The laser device is located on the straight line and is configured for emitting laser beams. Each of the rotatable reflecting mirrors is configured for reflecting laser beams from the laser device toward the corresponding connection portion and is configured for rotating so as to allow the laser beams from the laser device to reach the next rotatable reflecting mirror on the straight line.

Abstract: A laser machining device with a proximity-warning function in relation to a workpiece being machined includes a laser element and a position feedback unit. The laser element includes a laser head for emitting a focused laser beam and a movable member for moving the laser head. The position feedback unit is positioned on the movable member and connected to an alerting circuit. When an elastic contacting member in the position feedback unit is compressed because the distance between the laser head and the workpiece is less than a minimum permitted distance the alerting circuit issues an alert.

Abstract: A movable joining device for connecting structural components of an aircraft, with joining means moveably arranged on a guiding device situated on the outside of the structural components so as to fixedly connect joining edges of the structural components positioned adjacent to each other, wherein the joining means includes a welding unit that can move on the rail-like guiding device, and is equipped with a special so-called bobbin tool as a tool for friction stir welding.

Abstract: A method, including: providing a layer of powder material (106) on a substrate (12) having protruding rib material (26); and traversing an energy beam (100) across the layer of powder material to form a cladding layer (10) around and bonded to the protruding rib material, wherein the cladding layer defines a layer of an airfoil skin (94).

Abstract: A method prepares a repair material for and repairs a damage point in the surface of cast parts. Spray particles having the same cast structure as the cast part are used as materials. The particles are applied to the damage point by cold gas spraying. The cold gas spraying is performed such that the spray particles are not melted and, advantageously, the cast structure is retained after the spray particles contact the repair point. The repair point can thus be advantageously furnished with the same properties as the rest of the component to be repaired. The repair material can be produced in that a cast part having the required cast structure is reduced to small pieces.

Abstract: A method for finishing a shape of a component by machining, in which one area is produced by smelting with a thickened portion forming a first surface with a surrounding profile and a theoretical profile defined by a second surface, the method including: defining, on the second surface, a grid forming nodes and squares; defining each point over which the machining tool is to pass according to weighting coefficients equal to weight to be given to the nodes of the square in which the tool is located, to be the barycenter of assigned nodes of the coefficients; measuring, for each node located outside an outer limit, the delta between the first surface at the node and the theoretical position of the node; calculating deltas for each node within the outer limit by interpolation from already known deltas; using the weighting coefficients, defining the delta to be applied at each point.

Abstract: A supporting structure for positioning manipulating arms that may be fitted with tools. The manipulating arms are unblocked for their relocation and/or for relocation of tools or parts held by the manipulating arms. Relocation of the manipulating arms into a new position is by means of a robot. Once relocated, the manipulating arms are again blocked. A supporting frame is fitted with at least one sliding guide and/or spherical joint in which each manipulating arm is movably disposed. Blocking and unblocking of the manipulating arms is achieved through the use of pneumatic or electrical power.

Abstract: A screw locking device includes a feeding mechanism, a conveying mechanism, and a pneumatic screw driver. The conveying mechanism includes a base, a pneumatic driver slidably mounted on the base, a pair of blocking members slidably mounted on the base, a conveying bridge, a flexible tube, and a controller. Each blocking member includes a blocking end positioned below the pneumatic driver. The conveying bridge communicates with the feeding mechanism, and extends to the blocking ends. The flexible tube aligned with a gap between the blocking ends, and communicates with the pneumatic screw driver.

Abstract: A processing apparatus for container blanks, with a machine bed, a feed device for feeding container blanks, a discharge device for removal of container blanks, a rotatably mounted rotary worktable with several locating devices designed for conveyance of container blanks along a circular orbit section shaped conveyance path, wherein the conveyance path determines a first circle segment shaped surface section, several operating devices lying opposite the rotary worktable in the radial direction, and at least one conveyor designed for conveyance of components of container blanks and/or for container blanks along a conveyor section between a component mounting and an assigned operating device. The component mounting of the conveyor is located in a second circle segment shaped surface section, which supplements the first surface section determined by the circular orbit section shaped conveyance path to make a full circle.

Abstract: A silent knife-grabbing apparatus includes a stationary disc, a rotary bar, and two locking units each including a latch, a lever unit, and two pushers. The latch is movable between a releasing position to place a first end thereof substantially out of a space of a clasp of the rotary bar and a locking position to place the first end in the space. The lever unit is movable between a folded position to place the latch in the releasing position and an extended position to place the latch in the locking position. A first end of the first pusher normally contacts the stationary disc so that a second end of the first pusher places the lever unit in the folded position. An end of the second pusher places the lever unit in the extended position when the upper end of the first pusher enters a recess of the stationary disc.

Abstract: A system for re-profiling a first wheel in accordance with the first profile includes a lathe cutting tool and a plate. The first wheel is associated with a train or other rail riding device. The lathe cutting tool is configured to engage the first wheel and attach to a compound slide mechanism. The plate includes supports for supporting the wheel assembly including the first wheel. The plate is attached to the compound slide mechanism.

Abstract: The present disclosure provides a system and method for automatically adjusting a position of a panel on a chuck. The system includes: the chuck having a front end sensor and a rear end sensor arranged respectively on front and rear ends of the chuck in a direction of carrying the panel, and also having an adjustment unit arranged in a central area of the chuck; and a central control apparatus configured to receive a front end trigger signal transmitted by the front end sensor, and judge whether to enable the adjustment unit to adjust the position of the panel on the chuck based on whether a rear end trigger signal transmitted by the rear end sensor is received within a predetermined period of time after the front end trigger signal is received. In this way, the position of the panel with respect to the chuck can be adjusted efficiently, thereby accurately judging a condition of carrying the panel, and thus preventing a machine station from falsely generating an alarm and halt.

Abstract: A tool turret includes a tool disk (2) swivelable about a support column (32) that defines a swivel axis (26) into positions in which at least one machining tool fastened to the tool disk (2) is in a machining position. A drive device (14) includes drives (10, 8) connected by a controllable coupling device (18) to outputs (20, 22) used to drive the tool disk (2) or the machining tool. The drive device (14) is arranged inside the tool disk (2) together with the drives (8, 10) and the output (22) used to drive the machining tool. The output used to drive the tool disk (2) in a swiveling manner has a gear train arrangement (34) outside the tool disk (2) on the support column (32). The gear train arrangement has an output shaft (70) that extends along the support column (32).

Abstract: An apparatus for machining a workpiece has a housing having a vertical front wall and a first vertical side wall generally perpendicular thereto, respective first front and side vertical guides on the front and first side walls, and a first vertical slide extending along the front and first side walls. First front and side formations on the first vertical slide engage the first front and side guides for vertical movement of the first vertical slide relative to the housing. A first spindle unit adapted to hold the workpiece is carried on the first vertical slide, and a tool holder adapted to hold tools in a first work station is provided below the first vertical slide so that the spindle unit can engage the workpiece with a one of the tools in the work station.

Abstract: Method for sharpening a cutting tool. In some embodiments, a first abrasive belt is advanced along a belt path between first and second rollers. A cutting tool inserted into a v-shaped slot is drawn across the belt as a cutting edge is supported by a limit stop of the slot. The first abrasive belt is deflected at a first radius of curvature in relation to a first linear stiffness of the belt and a tension applied to the first roller. The first abrasive belt is replaced with a second abrasive belt, and the cutting tool is again inserted into the v-shaped slot and drawn across the belt as the cutting edge is supported by the limit stop of the slot. The second abrasive belt is deflected at a second radius of curvature in relation to a second linear stiffness of the belt and the tension applied to the first roller.

Abstract: [Object] An outer periphery polishing apparatus capable of polishing the edge of workpieces having different bevel angles is to be provided.

Abstract: A tool and a method for forming a pair of recesses on an endface of a fiber optic ferrule are disclosed. The tool includes a base, a ferrule holder slidingly mounted to the base along a guided path, and a pair of material removing members extending in a direction parallel to the guided path. The material removing members are spaced a distance perpendicular to the guided path from each other and mounted to the base. The tool includes a linkage that clamps and centers the ferrule about the tool. The recesses can adjoin pin holes of the ferrule. The linkage can be a parallelogram linkage.

Abstract: A polishing apparatus includes a platen having a first surface to support a polishing pad and a second surface, a carrier head to hold a substrate against the polishing pad, a plurality of through-holes defined in the platen, and a pad pressure control assembly adjacent on a side of the platen opposite the carrier head.

Abstract: The invention provides a chemical-mechanical polishing composition containing (a) abrasive particles, (b) a polymer, and (c) water, wherein (i) the polymer possesses an overall charge, (ii) the abrasive particles have a zeta potential Za measured in the absence of the polymer and the abrasive particles have a zeta potential Zb measured in the presence of the polymer, wherein the zeta potential Za is a numerical value that is the same sign as the overall charge of the polymer, and (iii) |zeta potential Zb|>|zeta potential Za|. The invention also provides a method of polishing a substrate with the polishing composition.

Abstract: A grinding wheel includes a base disk, and a plurality of teeth protruding beyond a surface of the base disk. The plurality of teeth is aligned to an elongated ring encircling a center of the grinding wheel.

Abstract: A polishing pad capable of maintaining a high level of dimensional stability during absorption of moisture or water includes a polishing layer including a polyurethane foam having fine cells, wherein the polyurethane foam includes a cured product of a reaction of an isocyanate-terminated prepolymer (a), a polymerized diisocyanate, and a chain extender, and the isocyanate-terminated prepolymer (a) includes an isocyanate monomer, a high molecular weight polyol (a), and a low molecular weight polyol. A method for manufacturing such a polishing pad includes mixing a first component containing an isocyanate-terminated prepolymer with a second component containing a chain extender and curing the mixture to form a polyurethane foam. The pad so made is used in the manufacture of semiconductor devices.

Abstract: An apparatus for processing a substrate is disclosed. The apparatus includes a polishing section configured to polish a substrate, a transfer mechanism configured to transfer the substrate, and a cleaning section configured to clean and dry the polished substrate. The cleaning section has plural cleaning lines for cleaning plural substrates. The plural cleaning lines have plural cleaning modules and plural transfer robots for transferring the substrates.

Abstract: A system for use in removing a multi-layer coating from a substrate is provided. The multi-layer coating includes a first coating applied to the substrate and a second coating applied over the first coating. The first coating is formed from a first material and the second coating is formed from a second material different from the first material. The system includes a grinding mechanism configured to remove the multi-layer coating from the substrate, and a controller coupled in communication with the grinding mechanism. The controller is configured to position the grinding mechanism against the multi-layer coating, initiate a first removal mode that directs the grinding mechanism to traverse across the substrate, monitor a variable operating parameter of the grinding mechanism during the first removal mode, and evaluate a value of the variable operating parameter against a predetermined threshold to determine whether the second coating has been removed from the substrate.

Abstract: A grinder includes a body having an annular portion, a wheel cover which is attachable to the annular portion, and a wheel cover holding member which holds the wheel cover. The wheel cover has a cylindrical portion which is attachable to the annular portion. The wheel cover holding member has a slide member and a pressing portion which moves the slide member. The pressing portion switches a state between an engagement state in which the slide member is engaged with the cylindrical portion and a disengagement state in which the slide member is disengaged with the cylindrical portion by moving the slide member. The pressing member moves on a second line which is parallelly offset from a first line passing the center of the annular portion in a predetermined direction.