Abstract: A torque tube propshaft assembly having an outer tube free to float with movements of an inner shaft (propshaft) by being free of rigid anchorage at each end. A plurality of shaft bearings interface the outer tube with the inner shaft, wherein the outer tube is generally co-extensive with the inner shaft. An anti-rotation mechanism prevents rotation of the outer tube with respect to the frame of the motor vehicle. An axial slip mechanism is integrated with at least one end of the inner shaft. A non-welded construction of the power carrying components is provided. The outer tube provides bending support so the inner shaft does not become dynamically unstable at any rotation speed including its critical speed.

Abstract: A washing machine with a vibration-absorbing structure for preventing the transfer of the vibration of the driving part is disclosed. The washing machine includes a rotor housing 50 in which a rotor is installed and which is rotatably moved, a driving shaft 20, 31, 33 for rotating a washing tub or a pulsator using a rotational force transferred from the rotor housing, a power transferring member 120 for transferring the rotational force of the rotor housing to the driving shaft, a rotor bushing 110 coupled to the rotor housing and through which the driving shaft penetrates to be slidingly moved, and at least one vibration-absorbing member 140, 150 installed on a path where a power is transferred from the rotor housing to the driving shaft, for absorbing vibration of the rotor housing.

Abstract: A damper insert for assembly in a tubular drive shaft of a motor vehicle includes a tubular sleeve, a helically wound, resiliently deformable wiper secured to the sleeve, and a corrugated winding secured to the sleeve. The wiper includes an arch that spans mutually spaced supports. The damper insert is sized to fit in the bore of the drive shaft such that the arch frictionally engages the surface of the bore and secures the insert in place within the shaft with a resilient press fit. The arch projects radially outward toward the bore beyond the radially outer surface of the winding.

Abstract: A rotary shaft may include a multi-piece liner for absorbing vibrations caused by rotational energy generated by the rear axle and/or clutch of a motor vehicle.

Abstract: In a dynamic damper including: a torque transmissible tube member; a mass member housed within an inside of the tube member concentrically to the tube member; and a pair of elastic members, both ends of the mass member in a center axis direction of the tube member are coupled to the tube member via the pair of elastic members, the mass member includes a large mass section interposed between the pair of elastic members, a length of the mass member in the center axis direction of the tube member is longer than a diameter of the large mass section, and, from among two different bending resonance vibration modes of the tube member, a node of a higher order bending resonance vibration mode is placed at a position between the pair of elastic members.

Abstract: A compressor has a compression unit for compressing gas to a desired pressure, a drive shaft and a balancer. The drive shaft is connected to the compression unit for driving the compression unit. Imbalance on the drive shaft is generated due to movement of the compression unit. The balancer is mounted on the drive shaft and includes a main portion and adjustable portion for correcting the imbalance on the drive shaft. Preferably, at least one of the weight and the shape of the adjustable portion is adjustable.

Abstract: A pulley (1) that is decoupled from the vibrations of a crankshaft and that has an integrated viscous torsional vibration damper (2), including a flywheel (3), which is arranged in a damper housing (5) that is filled with a viscous medium (4) and which can rotate relative to the housing, as well as a bearing (6) and a coupling (7) made of rubber elastic material, for supporting the pulley (1) with respect to the damper housing (5) in a flexible manner in the circumferential direction of the pulley and so as to be capable of relative rotation, the pulley (1) being assigned to the flywheel (3) so as to be axially adjoining. The damper housing (5) has at least one first axial projection (8), which is enclosed by the belt-bearing surface (9) of the pulley (1) at a radial clearance, and the bearing (6) is arranged in the gap (10) that is formed by the clearance.

Abstract: In order to provide a cutting device, comprising a machine frame, an anvil roller which is mounted for rotation on the machine frame and a cutting tool which is mounted for rotation on the machine frame, wherein the cutting tool has a cutting edge cooperating with anvil surfaces of the anvil roller, with which the springing away on account of lateral cutting forces is minimized it is provided for the cutting tool to be biased essentially parallel to its axis of rotation.

Abstract: A shaft (1) with a co-rotating element (2) which is secured to it and has a surface located perpendicular to the axis (3) of the shaft, the welding taking place in the fillet formed between the seating surface (4) of the shaft (1) and axially normal surface (6, 8) of the element. To achieve a durable join without adversely affecting true running, a welding bead (20) starts at a starting point (21) on the surface (6; 8) located perpendicular to the axis (3) of the shaft (1), leads to the fillet and then leads back to an end point (21?) on the surface (6; 8) located transversely with respect to the axis of the shaft.

Abstract: A propeller shaft assembly includes a thin-walled tubular member, a connecting member fixed to each end of the tubular member, and a support member fixed within the tubular member. The support member includes a foamed plastic impregnated with a high modulus resin or cement extending a first length (L1) within the tubular member and engaging an interior surface of the tubular member to increase the bending frequency of the propeller shaft assembly.

Abstract: A support system, a bracket assembly, and a damping member for use in supporting a rotating shaft. A support system including a fixed bracket; a bracket assembly; and a bearing. The bracket assembly having a first damping member having a first fixed end and a second movable end, the first fixed end being securably attached to the fixed bracket and the second movable end being movable in a first plane aligned with the shaft. The bracket assembly further having a brace securably attached to the second movable end of the first damping member. The bracket assembly further having a second damping member having a first end and a second end, the first end being securably attached to the brace and the second end being movable in a second plane that is aligned with the shaft and is generally perpendicular to the first plane.

Abstract: A lightweight damper for reducing noise and vibration in torque transferring assemblies that is easily assembled and cost efficient. The damper may be formed from a foam material having a density less than 1.4 lb/ft3, and includes an outer surface that is resiliently biased against the inner surface of a tubular shaft when installed. In a second embodiment, the damper is formed from a sheet of material that dissipates energy such as noises and vibrations through movement of the layers relative to each other. In third embodiment, the dampening sheet and foam damper are combined to provide a damper that dampens noises and vibrations across a large frequency range.

Abstract: This invention provides a dynamic damper comprising an outer pipe 20, a weight 30 and an elastic body 40, wherein convex portions 21 protruded in the direction of the inside diameter are provided at plural positions along the circumferential direction of the outer pipe so as to hold the elastic body 40 by sandwiching the outer circumferential portion of the elastic body 40 between adjacent the convex portions.

Abstract: A drive train with a torsional vibration damper and a torsionally flexible coupling is described, with the torsional vibration damper comprising a damping mass on the driven side which is resiliently supported with respect to a part (1) on the drive side and the torsionally flexible coupling comprising a damping mass on the drive side which is resiliently supported with respect to a part (11) on the driven side. In order to provide advantageous constructional conditions it is proposed that the torsionally flexible coupling and the torsional vibration damper are assembled into a modular unit with a common damping mass for the torsional vibration damper and the torsionally flexible coupling.

Abstract: A torque transmission device includes a pulley, a cylindrical member, a torque limiter and a weight member. The pulley is rotated by torque transmitted from a drive source. The cylindrical member is connected to a rotatable shaft of a compressor and is rotated integrally with the rotatable shaft. The torque limiter is arranged between the pulley and the cylindrical member and transmits the torque from the pulley to the cylindrical member. The torque limiter disables the transmission of the torque when the torque becomes equal to or greater than a predetermined value. The weight member is secured to the cylindrical member at a point closer to the rotatable shaft than the torque limiter.

Abstract: A drive shaft assembly (8) for automotive applications for transmitting a rotary drive. The drive shaft assembly (8) comprising a central flexible rotatable core shaft (14), an outer sleeve (12) surrounding the central flexible core shaft (14) and spaced from the core shaft (14), and at least one elastomeric damper (20) positioned at a location (42) along the length (l1) of the drive shaft assembly (8). The damper (20) extending to and lightly abutting against an outer cylindrical surface of the core shaft (14).

Abstract: An integrated axle flange and torsional damper component for use on a vehicle having a driveshaft is disclosed. The integrated component includes a structural axle flange for transmitting torque, a torsional damper and an elastic component positioned between the structural flange and torsional damper. The method of constructing the integrated axle flange and torsional damper component and assembling the component to a vehicle is also disclosed. The method includes attaching the integrated component to the vehicle's driveline and balancing the driveline after attachment of the integrated component.

Abstract: An image forming apparatus includes a photoreceptor belt formed by either a belt or a thin-walled cylinder. A charging unit that sets bias characteristics of the photoreceptor belt has an arrangement to approach towards the photoreceptor belt. A damper is provided on a side of the photoreceptor belt opposite to the side facing the charging unit. The damper absorbs vibrations in the photoreceptor belt through a supporting plate.

Abstract: A method for damping torsional vibrations in a rotating shaft. The method includes coupling an actuator to a shaft; rotating the shaft; determining an amount of torsional vibration in the shaft; and controlling the actuator in response to the amount of torsional vibration and a rotational position of the shaft to damp the torsional vibration in the shaft.

Abstract: A balance correction device is supported within a hollow article, such as a driveshaft assembly for a vehicular drive train system, to balance the article for rotation. The balance correction device includes a first disc having a first slot provided therein and a second disc having a second slot provided therein. Portions of the first and second slots are axially aligned with one another. An object, such as a ball, is received within the axially aligned portions of the first and second slots. The first and second discs can be positioned relative to one another to position the object relative to the unbalanced article to balance the unbalanced article for rotation.

Abstract: A drive shaft extends into a tubular member for use in a portable working machine. The drive shaft is mounted relative to the tubular member so as to undergo rotation relative to the tubular member. The drive shaft has a longitudinal axis and resin bushes integrally mounted on the drive shaft for rotation therewith at positions along the longitudinal axis corresponding to vibration nodes of the drive shaft. Each of the resin bushes has an outer peripheral surface disposed in slidable contact with an inner peripheral surface of the tubular member.

Abstract: A method of manufacturing a tube for a vehicle driveshaft assembly forms a flat sheet of material having a greater thickness than other portions over a portion of its width and along its length, rolling the sheet about a longitudinal axis such that its lateral edges are mutually adjacent, then securing the lateral edges together by seam welding to form a tube. The mass distribution is not uniform because the wall thickness of certain portions of the tube is greater than the wall thickness of other portions of the tube. A tube yoke is machined and the angular location of its overbalance about its longitudinal axis is determined. The tube is secured to the tube yoke such that the angular location of overbalance of the yoke is aligned with the weld seam and diametrically opposite the region of the tube having the greater wall thickness.

Abstract: A dynamic damper including: a cylindrical metallic mass; a cylindrical fixing member with an inner diameter smaller than that of the metallic mass member; a connecting member connecting the metallic mass member with respect to the fixing member; and a covering member integrally formed with the cylindrical fixing member and the connecting member, and covering the mass member. A plurality of engaging recesses are formed at axial end portions of the mass member to be open in an outer circumferential surface thereof, and a plurality of engaging projections integrally formed with the covering member are held in stable engagement with the engaging recesses, respectively.

Abstract: A propshaft assembly with a shaft structure and an insert member. The insert member has a front end having a first slot and a rear end having a second slot. The first slot is configured to at least partially overlap the second slot providing a staggered slot configuration, which ensures a proper fit when installed into the shaft structure.

Abstract: This invention provides a dynamic damper 10, in which convex portions 21 protruded in the direction of the inside diameter are provided at plural positions along the circumference of the outer pipe 20, and an elastic body 40 is held between the convex portion 21 and the outer circumference of the weight 30. A stopper portion 32 which is capable of engaging the convex portion 21 of the outer pipe 20 in the axial direction of the pipe is provided on the weight 30.

Abstract: Device and method for forming the device are provided. The device is exposed to vibration events from time-to-time and includes at least one component assembled therein. The device includes a spool including a bore defined by an inner section of the spool. The inner section that defines the bore may be configured to receive that component. The device further includes a rib situated on the inner section near an entrance to the bore. The rib may extend about the periphery of the bore entrance. The rib is configured to provide a tight interference-fit upon assembly of the component into the bore, and thus avoid vibration-induced effects between the inner section of the spool and the component therein.

Abstract: A chain-driven engine balancer has an elastomeric or compliant isolator ring in a balancer drive sprocket to decouple chain whine vibration from an associated balance shaft. The isolator substantially reduces the transmission of chain whine noise to the engine structure. A splined isolator ring is placed between internal and external splines formed on a toothed outer ring and hub respectively of the associated sprocket. The splines are configured to be in loose engagement so that, upon failure of the elastomeric isolator ring, direct engagement of the hub and ring splines with one another will maintain the timing of the balance shafts with respect to the engine crankshaft. In a specific embodiment, application of an isolator ring in only the most heavily loaded sprocket of dual balance shaft sprockets driven in series by the chain eliminates most of the vibration transmission. However, isolation of multiple chain sprockets could be desirable.

Abstract: A gas turbine engine flanged shaft (120) is provided with a plurality of anti-score plates (6a, 6b) each of which has two openings which are aligned with corresponding apertures on the flange. Bolts (4) pass through the openings and apertures to attach the anti-score plates (6a, 6b) to the flange (2). The anti-score plates (6a, 6b) have different masses to facilitate shaft balancing.

Abstract: A process for balancing a vehicular driveline including a propeller shaft and an input shaft of a vehicle axle interconnected by a universal joint. First, the vehicle propeller shaft is balanced to a predetermined residual imbalance having an imbalance vector angle of 0° or 180° which lies inline with open set of cardan joint trunnions. The corrected residual imbalance is then visually marked. Next, the input shaft is balanced to a predetermined residual imbalance having an imbalance vector angle of 0° or 180° which lies inline with cross-holes in yoke ears. Again, the corrected residual imbalance on the input shaft is then visually marked. During the assembly of the vehicle, the assembly line operator couples the propeller shaft to the input shaft through a cardan joint cross by aligning the marks on the propeller shaft and the input shaft so that the marks are located opposite to each other.

Abstract: An axial plunging unit for torque transmission within a driveline which includes a profiled journal (11) with first circumferentially distributed longitudinally extending ball grooves (12), a profiled sleeve (13) with second circumferentially distributed longitudinally extending ball grooves (14), balls (15) which are arranged in pairs of first and second ball grooves (12,14) in identical groups, and a supporting and attaching sleeve (21) which is slid on to the profiled sleeve (13) so as to ensure the transmission of torque.

Abstract: A damper mechanism for absorbing torsional vibrations in a rotating shaft. The damper mechanism includes a vibration absorbing mechanism and at least one actuator that is controllable to affect the torsional vibration absorbing characteristics of the vibration absorbing mechanism.

Abstract: A dynamic damper for damping vibration of a rotary shaft. The dynamic damper includes a tubular mass member and a rubber elastic member. The rubber elastic member includes an attachment tube press-fitted onto the rotary shaft and an arm. The attachment tube is disposed coaxially with the mass member but nearer to an axial center thereof than the mass member. The arm connects the attachment tube to the mass member. The attachment tube includes a tubular support portion connected to the arm, a tubular attachment portion, and a tubular coupling portion for coupling the tubular support portion with the tubular attachment portion. The tubular attachment portion has larger interference than the tubular support portion.

Abstract: A shaft structure and at least two non-identical inserts. The shaft structure has a cavity and vibrates in response to the receipt of an input of a predetermined frequency such that at least two second bending mode anti-nodes are generated in spaced relation to one another along the longitudinal axis of the shaft structure. Each of the inserts is disposed within the longitudinally extending cavity at a position that approximately corresponds to an associated one of the anti-nodes. A method for attenuating noise transmission from a vehicle driveline is also disclosed.

Abstract: An internal combustion engine includes a balancer housing, a balancer shaft having an eccentric weight portion and disposed within the balancer housing so as to be parallel with and rotatable in timed relation with a crankshaft, and a power transmitting mechanism that transmits rotation of the crankshaft to the balancer shaft, wherein the balancer shaft has an end portion protruding outward of the balancer housing, and wherein the end portion of the one balancer shaft is partially cut to have a flattened section that constitutes a device for positioning the balancer shaft in a predetermined rotational position. A method of assembling an internal combustion engine with a balancer shaft is also provided.

Abstract: A vibration damper for a tubular propeller shaft in the drive train of a motor vehicle having a mass body mounted concentrically, in the propeller shaft or in a sleeve attached in the propeller shaft, by way of at least one rubber spring element. Metal and/or flexible rubber stop elements that limit the vibration travel of the mass body at least in the radial direction are arranged between the mass body and the sleeve. Alternatively, the mass body and/or the sleeve are configured at least locally, in mutually opposite regions, as stop elements that limit the vibration travel of the mass body at least in the radial direction.

Abstract: A vehicular drive shaft assembly is balanced about an axis of rotation. The vehicular drive shaft assembly includes a drive shaft tube having a first end and a second end, with a first tube yoke including a first radially outer wall fixedly mounted to the first end of the drive shaft tube. A first balance pendulum is located radially inward of the first outer wall and rotationally fixable relative to the first tube yoke, and a second balance pendulum is located radially inward of the first outer wall and is also rotationally fixable relative to the first tube yoke. The balance pendulums can be rotated before being locked in place in order to account for imbalances in the drive shaft assembly. A second tube yoke fixedly mounted to the second end of the drive shaft tube may also include balance pendulums, similar to the first, in order to provide additional drive shaft assembly balancing capabilities.

Abstract: The present invention provides a method and apparatus for applying a uniformly-distributed pattern of stripes (8) on a component (6) of a large rotary machinery, such as an industrial generator. A method is provided that comprises measuring the circumferential area of the component (6) with a measuring element (14). The precise circumference is indicated and a desired number of pattern segments is determined. The circumference is divided by this number to produce equally spaced segments. This is then transferred to the rotor shaft (6) by marking on the measuring element (12) the number of segments and making a copy of the markings onto a second strip (14). These strips are then aligned on the circumferential area and cross strips (22) are placed at each of the segment marks (16). The segment areas not covered by the cross strips (24) are then painted in a color that is optically distinguishable from the non-painted regions.

Abstract: A shaft structure and at least two non-identical inserts. The shaft structure has a cavity and vibrates in response to the receipt of an input of a predetermined frequency such that at least two second bending mode anti-nodes are generated in spaced relation to one another along the longitudinal axis of the shaft structure. Each of the inserts is disposed within the longitudinally extending cavity at a position that approximately corresponds to an associated one of the anti-nodes. A method for attenuating noise transmission from a vehicle driveline is also disclosed.

Abstract: A dynamic damper for absorbing vibrations in a rotary driveshaft, including a mass member assembly having a plurality of mass members, each mass member having an inner surface, an outer surface, and an affixing member to affix the mass member to another mass member of the assembly, the mass member assembly being affixable to a rotary shaft.

Abstract: A method for manufacturing a driveshaft assembly takes advantage of the asymmetrical nature of the driveshaft tube and end fittings to reduce the initial imbalance of the driveshaft assembly. The method includes the initial steps of providing a driveshaft tube having a heavy side and providing an end fitting having a heavy side. The heavy side of the end fitting is aligned so as to be opposite the heavy side of the driveshaft tube. Finally, the driveshaft tube and the end fitting are secured together. The dimensional characteristics of the driveshaft tube and end fitting improve the balancing capability of the driveshaft assembly by permitting levels of imbalance of the driveshaft assembly to be lowered and better-managed.

Abstract: A rotationally balanced shaft assembly having a shaft and a bead of balancing material. The shaft has an axial length and an outer surface. The bead is adhered to the outer surface of the shaft and has a length that is greater than its width. The rotationally balanced shaft is also defined as having an initial imbalance angular position along the outer surface of the shaft with the bead being centered on the angular position along the length of the bead. The invention is also directed to a method of balancing a shaft using a balancing material applicator. The method includes the steps of determining an imbalance of the shaft, aligning the balance material applicator, and the angular position of the initial imbalance, and dispensing balancing material from the applicator while causing relative axial movement between the applicator and the shaft.

Abstract: A driveshaft assembly is balanced for rotation during use by initially disposing an annular band about a portion thereof. The band is then secured to the driveshaft assembly, such as by welding, adhesives, frictional engagement, and the like. After the band is secured to the driveshaft assembly, one or more balance weights can be secured to the band, such as by welding, adhesives, and the like, at desired locations to balance the driveshaft assembly for rotation. The band functions as a mounting surface upon which the balance weights can be secured to balance the driveshaft assembly for rotation. Because the balance weights are secured not directly to the driveshaft assembly, but rather are mounted indirectly thereon by the band, the driveshaft assembly is protected from damage that might otherwise result from welding the balance weights directly thereto.

Abstract: A shaft structure and at least two insert members. The shaft structure has a longitudinally extending cavity and is configured to vibrate in response to the receipt of an input of a predetermined frequency such that at least two second bending mode anti-nodes are generated in spaced relation to one another along the longitudinal axis of the shaft structure. The insert members are disposed within the longitudinally extending cavity and engage an inner wall of the shaft structure. Each of the insert members is located at a position that approximately corresponds to an associated one of the anti-nodes and has a density that is tailored to an anticipated displacement of the associated anti-node. A method for attenuating noise transmission from a vehicle driveline is also disclosed.

Abstract: A drive system that includes a drive shaft, which is or can be brought into torque-transmitting connection with a drive train, a secondary drive system for transmitting torque between the drive shaft and at least one auxiliary unit, and at least one vibration-damping device including a deflection mass carrier with freedom to rotate around a rotational axis and at least one deflection mass, which can shift position relative to the deflection mass carrier in at least one deflection plane. Upon deflection of the at least one deflection mass from the home position relative to the deflection mass carrier, the radial position of the deflection mass changes relative to the rotational axis. At least part of the vibration-damping device can be integrated into part of the secondary drive system.

Abstract: A plant cutter apparatus has a one-piece handling rod having an outer pipe portion, an inner pipe portion disposed concentrically within the outer pipe portion, and first, second and third radial stay portions extending between and interconnecting the outer pipe portion and the inner pipe portion. The first, second and third radial stay portions are arranged at non-equal angular intervals such that an angle &thgr;1 formed between the first and second stay portions, an angle &thgr;2 formed between the second and third stay portions, and an angle &thgr;3 formed between the third and first stay portions differ from each other. A drive shaft extends through the inner pipe portion and is rotatably supported within the inner pipe portion via a bushing disposed between the drive shaft and the inner pipe portion. A drive source unit is mounted at one end of the handling rod for rotating the drive shaft.

Abstract: This invention provides a dynamic damper 10, in which convex portions 21 protruded in the direction of the inside diameter are provided at a plurality of positions along the circumference of the outer pipe 20 and an elastic body 40 is held between the convex portion 21 and the outer circumference of the weight 30. A stopper portion 32 capable of engaging the convex portion 21 of the outer pipe 20 in the axial direction of the pipe is provided on the weight 30. An insertion guide face 23 provided at an end portion in the axial direction of the convex portion 21 of the outer pipe 20, and the convex portion 21 of the outer pipe 20 makes the insertion guide face 23 slide against the stopper portion 32 of the weight 30 to enlarge the diameter of the convex portion elastically to surpass the stopper portion 32 so that it fits to the outer circumference of the weight 30.

Abstract: An apparatus and method for damping vibration of a vehicle part, such as a steering wheel or an electric motor. According to one embodiment, an apparatus (26) for damping vibration of a vehicle part (12) includes at least one container (50) having a chamber (56) defined by at least one interior wall (58). The container (50) is associated with the vehicle part (12). A plurality of particles (52) is disposed in the chamber (56). The particles (52), when at rest, occupy a first portion (82) of the chamber (56) and define an unoccupied second portion (84) of the chamber. The particles (52) move back and forth between the first and second portions (82 and 84) of the chamber (56) in response to vibration of the vehicle part (12) and collide with each other and with the interior wall (58) defining the chamber to damp the vibration of the vehicle part.

Abstract: A method of attaching a balancing mass to a rotational member which has to be balanced and comprises a longitudinal axis X. The method uses magnetic pulse welding, wherein the balancing mass, at a high speed, is radially moved towards the longitudinal axis of the rotational member and, when hitting the rotational member, becomes welded thereto.

Abstract: Balance shaft assemblies are used in internal combustion engines to dampen primary and second order inertia forces. Known balance shaft assemblies typically require precision manufacturing and a rigid frame or housing. A balance shaft assembly (1) in accordance with this invention provides a low cost and less complex solution to engine balancing. The balance shaft assembly (1) includes an elongate housing (2) having a front end and a rear end, a balance shaft (5) which is rotatably supported between a front end bearing (6), a rear end bearing (7) and an intermediate bearing (12) in the housing (2). The housing (2) is transversely flexible relative to the balance shaft (5) to accommodate misalignment of the intermediate bearing (12) relative to the front and rear end bearings (6, 7). Consequently, the balance shaft assembly (1) can be less complicated and manufactured at a lower cost than known balance shaft assemblies.

Abstract: This invention provides a dynamic damper comprising an outer pipe 20, a weight 30 disposed inside the outer pipe 20 and an elastic body 40 interposed between the outer pipe 20 and the weight 30. The outer pipe 20 contains slit 21 crossing the circumferential direction of the outer pipe 20 and the slit 21 may be filled with elastic filler 50.