A cable-driven liner loading system for loading of an invertible liner onto a trailer bed and unloading the invertible liner from the trailer bed. A movable trolley is supported between a pair of tracks defined by C-shaped members. The movable trolley is actuated by a cable system that is driven by a winch and a set of pulleys, permitting the movable trolley to move along an axis of the trailer bed to facilitate loading of the invertible liner in a serpentine-like manner.

A lifting apparatus for a lift system is disclosed. The apparatus includes a) a motor adapted for providing a lifting force, b) at least one connector operatively connected to the motor, the connector adapted for connecting a load-bearing component to the motor, c) an information receiver for receiving a load limit information about the load-bearing component, d) a motor controller electrically coupled to the motor and the information receiver, wherein the motor controller is adapted to limit the lifting force of the motor based on the load limit information received by the information receiver.

Various embodiments include a service apparatus for a turbomachine. The service apparatus can include: a frame for coupling to an opening in the turbomachine; a bridge member operably coupled to the frame and spanning a width of the frame, the bridge member being substantially movable along a length of the frame; and a crane member operably coupled to the bridge member, the crane member being substantially movable along the width of the frame, wherein the crane member includes at least one attachment device for attaching to an object within the turbomachine.

A method for controlling a hoisting or lowering movement of a load, which is suspended from a hoisting mechanism of a crane by means of at least two hoisting cables trained round cable sheaves on the load, by monitoring the position of the load and braking and/or stopping the hoisting mechanism upon detection of an undesirable position, wherein the cable sheaves are each connected to the load for pivoting about a horizontal axis, and the position of the load is monitored by detecting a pivoting movement of at least one of the cable sheaves.

A compressible stop member for use on a crane includes: a housing having a first sealed end, a second end, a first cylindrical surface and a second cylindrical surface; a free piston slidably contained within the housing in a sealing engagement with the first cylindrical surface; a compressed gas chamber in the housing between the free piston and the first sealed end; and a rod comprising a cylindrical portion with a diameter less than the diameter of the second cylindrical surface and a rod support portion that separates a first liquid chamber comprising the volume inside the housing between the free piston and the rod support portion from a second liquid chamber comprising the volume between the rod support portion and the second end of the housing. Also, the rod support portion includes at least one flow channel allowing liquid to flow between the first and second liquid chambers.

Hoisting crane (20), comprising a substantially hollow jib (24,-124; 324) having a longitudinal axis, and comprising one or more hoisting cable guides (47, 48, 49; 147; 347). The jib comprises at least one jib leg (29; 129; 329) extending between a jib connection member (26) and a jib hoisting end (27; 127; 327), wherein the at least one jib leg comprises one or more hybrid portions (160; 360) comprising two elongated hollow casings (170; 370) substantially parallel to each other and substantially parallel to the longitudinal axis of the jib, and wherein between the two casings a truss (171 371) is provided to rigidly connect the two castings.

The present disclosure relates to a crane with a travelling undercarriage, an uppercarriage rotatably mounted on the same with a luffing boom and derrick boom arranged on the same, and a ballast carriage connectable with the uppercarriage via a coupling element, wherein the ballast carriage is a standardized heavy-duty transport device with separate drive and separate drive controller, and wherein this drive controller can be influenced as a result of the movement of the crane.

A method and an apparatus for handling and/or servicing components of a wind turbine, such as installing and/or dismantling components into or from a wind turbine nacelle or such as servicing exterior components such as blades, hub, tower and nacelle of the wind turbine are disclosed. The gripping apparatus comprising at least one arm for gripping around the wind turbine tower, the at least one arm capable of forming a gap between gripping elements of the gripping apparatus. The at least one arm extends around the entire outer circumference, seen perpendicular to a horizontal plane, of the wind turbine tower.

A crane, in particular a lattice mast crane, having a bottom hook block with a load suspension means, in particular a load hook, wherein the bottom hook block has at least one winch whose outgoing control rope is connected or connectable to the crane boom for securing and/or aligning the load position or bottom hook block position.

The present invention provides devices, apparatuses, and systems for lifting and mounting of clinical- and research-related equipment. In particular, the present invention provides a lift and mount system for mass spectrometers (e.g., for time of flight (TOF) mass spectrometers (MS)).

The invention relates to a monitoring and alarm device for construction machinery having long and heavy booms, such as cranes, in particular mobile cranes, is characterized in that a monitor system is provided, which monitors parameters that may change in case of an undesired lowering of the boom or of boom sections in a non-operating condition, and triggers an optical and/acoustic and/or wireless alarm system if the parameters change.

A method of swing stopping control of a suspended load of a crane including a hoist and a trolley solves an equation of motion, given as an equation with respect to the deviation angle of a suspended load from the vertical direction when the trolley travels, for the trolley acceleration to thereby obtain the value of the acceleration or deceleration of the trolley, obtains speed patterns corresponding to the values of the acceleration or deceleration, drives the trolley according to the obtained speed patterns, and carries out control so that the deviation angle of the suspended load from the vertical direction becomes zero at the time when the acceleration or deceleration of the trolley is ended. Thus, even if the length of a rope holding the suspended load up is changed, a required speed pattern is produced to permit highly accurate positioning.

A luffing-jib tower crane, comprising a tower and a jib which is connected to the tower via a joint and is held by a luffing cable, wherein the length of the luffing cable can be changed by a drawing-in unit, by the luffing cable being wound onto or unwound from a cable drum of the drawing-in unit, wherein the angle of the jib with respect to the horizontal plane is measured by a first sensor winch is attached to the jib (first angular value), wherein a measuring device measures the length of the unwound part of the luffing cable, from which length the minimum angle of the jib with respect to the horizontal plane (second angular value) can be calculated, and the first angular value can be compared with the second angular value.

In one aspect, the invention is directed to an overhead crane with one or more bridge rails, that incorporates a reinforcement truss into its one or more bridge rails so as to reduce the overall mass of the one or more bridge rails. This facilitates movement of a load carried by the bridge by an operator to a destination point, particularly in embodiments wherein the one or more bridge rails do not have any bridge drive motors thereon. Reducing the mass of the bridge can increase the amount of lifted load that can comfortably be maneuvered by an operator, particularly when the bridge is manually moved along the runway. Additionally, reducing the mass of the bridge reduces the momentum associated with the bridge, which can increase the amount of control that the operator has when it is desired to stop the bridge when the load has been maneuvered to its desired destination point. The second reinforcement members may have first and second ends that are inserted into receiving apertures in the first reinforcement member and in a bracket that mounts to the bridge rail respectively. In embodiments wherein the bridge includes two rails and is capable of supporting a load in such a way as to generate a downward force that is offset from the bridge axis, the second reinforcement members may be connected to the first reinforcement member and to brackets in such a way as to prevent the withdrawal of the second reinforcement members from the receiving apertures.

A counterweight block apparatus includes a pair of interconnecting counterweight blocks having top and bottom surfaces, the counterweight blocks forming a plane of interconnection along adjacent sides thereof; and a shear bar releasably secured between the adjacent sides of the interconnecting counterweight blocks, generally perpendicular to the plane of interconnection, to provide resistance to relative vertical movement of the interconnecting counterweight blocks along the plane of interconnection. In another aspect, each counterweight block includes in at least one side thereof an indentation from a top of the counterweight block to a depth more shallow than the thickness of the counterweight block, the indentation defining a lip for hand grabbing. An aperture may be formed through the rest of the thickness of the counterweigh block at each indentation, wherein a securing strap can be run through each aperture of a stacked plurality of counterweight blocks to secure them to each other.

Disclosed is a crane comprising: a lower body; an upper slewing body; a counterweight unit including a plurality of wheels to travel on the ground in a turning direction equal to a slewing direction of the upper slewing body while being suspended from the upper slewing body; a steering actuator for rotating each of the wheels around a steering-rotation center axis to change the steering angle; and a steering control device for controlling the steering actuator. The steering control device includes: a slewing-identification-signal receiving section which receives a slewing identification signal for identification of the slewing direction of the upper slewing body; and an actuator operating section operates the steering actuator to orient each of the wheels to the inside of a tangent line to an orbit of the wheel at the steering-rotation center axis, based on the identified slewing direction identified from the slewing identification signal.

A controlling method for a hook deviation to regulate the deviation angle of a telescopic crane hook, involves following steps: A. Detecting the deviation angle and deviation direction of a rope, which is linked to the hook, in the horizontal plane relative to the direction of gravitational force; B. Judging whether the deviation angle is more than the predetermined value, if the deviation angle is more than the predetermined value, then turning to step C, and if the deviation angle is less than the predetermined value, then turning to step A; C. Compensatively controlling the deviation angle of the hook according to the deviation angle and direction. And a controlling system for the hook deviation and a controlling device for the hook deviation are provided. The method or system or device enables the detection of the deviation angle and direction of the hook in a quick and precise manner, and the compensatory control of the deviation angle of the hook is performed according to the detected deviation angle and direction, thus it avoids overdependence on human factor and reduces potential safety risks.

The present disclosure relates to a hydraulic braking apparatus for a crane drive for carrying out crane work, in particular a slewing gear, having at least one hydraulic stopping brake for braking the drive movement of the crane drive in an emergency situation, wherein at least one pressure regulation valve is provided for controlling at least one stopping brake to ensure a time-delayed braking torque build-up.

A method for mounting a wind turbine blade to a wind turbine hub by use of a crane boom is provided. An orientation of the blade is kept substantially horizontal when the blade is lifted off the ground and mounted to the rotor hub. Control wires, which connect the blade via the crane boom to a winch arrangement, are used for keeping the blade orientation substantially horizontal in addition to at least one bearing wire for bearing the blade weight.

Disclosed is a hoist apparatus having an improved structure to load an object to be transported in a horizontal direction. The hoist apparatus includes a travel unit to travel along a rail, a carrier unit coupled to the travel unit so as to move in a first direction, and a cart unit coupled to the carrier unit so as to move in a second direction different from the first direction, wherein the cart unit includes a body portion, in which an object to be transferred is located, and a drive portion to drive the body portion in the second direction.

An elevator including a car is arranged in a shaft. A set of compensator cables are attached to a bottom of the car and engaged with a compensator drum. A set of hoist cables are attached to a top of the car and engaged with a hoist drum to move the car vertically in the shaft, wherein the set of compensator cables and the set of hoist cables are configured to only move the car vertically.

Rail-mounted lift systems are disclosed. In one embodiment, the lift system includes a rail having at least one conductor positioned on an upper interior surface of the rail. A carriage may be slidably disposed in the rail for relative movement to the rail. The carriage generally includes a carriage body, at least one pair of support wheels rotatably coupled to the carriage body and slidably engaged with the rail, and a conductor truck comprising at least one conductive roller rotatably attached to the conductor truck. The conductor truck may be mounted to the carriage body with a biasing member upwardly biasing the conductive roller into rolling engagement with the at least one conductor. A lift unit may be coupled to the carriage body and includes a motor paying out and taking up a lifting strap. The lift unit is electrically coupled to the at least one conductive roller.

A fly jib for a crane having a load block includes a variable length beam to which a load can be connected. A rotation mechanism is connected to the variable length beam, and is connectable to the load block so that said rotational mechanism can selectively rotate the variable length beam with respect to the load block. A balance mechanism is connected to the variable length beam, the balance mechanism automatically keeps the variable length beam in a horizontal position.

A mobile lift crane includes a carbody; a rotating bed; a boom; a moveable counterweight unit; at least one linear actuation device; and at least one arm pivotally connected at a first end to the rotating bed and at a second end to the linear actuation device. The arm and linear actuation device are connected between the rotating bed and the counterweight unit such that extension and retraction of the linear actuation device changes the position of the counterweight unit compared to the rotating bed. In one method of operation, the counterweight unit is never supported by the ground during crane pick, move and set operations other than indirectly by the ground engaging members on the carbody.

A movement system includes a bridge crane, a trolley, and a movement device. The movement device includes an attachment portion, a plurality of housings, first and second curved elements, a cable, and a cable angle sensor. The curved elements are pivotally attached to housings and perpendicularly overlap with one another such that a first slot defined in the first curved element is perpendicular to a second slot defined in the second curved element. The first curved element is pivotable about a first axis and the second curved element is configured to pivot about a second axis. The cable extends from the attachment portion and through each of the slots. The cable is pivotable to angularly displace at least one of the curved elements about a respective axis. The cable angle sensor is configured to measure the angular displacement of the at least one of the first and second curved elements.

A portable lifting system includes a moveable base component including a scissors lift assembly, and a crane assembly coupled the movable base component, the crane assembly including a support member and a boom coupled to the support member.

The invention relates to a device for mounting and/or dismantling a component (10), in particular a rotor blade of a wind turbine (20) comprising a tower head (21). Said device comprises at least one guide element (30) that stretches between the tower head (21) and the ground (40) and has at least one supporting device (60) that is essentially fixed in the air, supporting at least a partial load of the weight of the component (10) during the transport of the latter (10) between the ground (40) and the wind turbine (20). At least one guy (70) leads from the supporting device (60) to the component (10), whereby the length of said guy between the supporting device (60) and the component (10) can be modified.

A traveling crane includes a longitudinal beam displaceable on rails. A traveler having a hoisting winch with a cable drum is displaceable in a transverse direction, and is operable to wind a cable reeved through at least one lower block. The hoisting winch is displaceable relative to the traveler in a hoisting winch travel direction such that a cable run out point remains in one location relative to the longitudinal extent of the cable drum. Two winching hoists are provided which are displaceable transversely to the longitudinal beam with respective cable drums thereof being disposed parallel to and spaced from each other. A common cable can be wound up and down by the two cable drums, and the two cable drums include cable grooves running in opposite directions. The two cable drums are operable in the opposite direction of rotation for lifting and lowering a load.

When an extension pattern selection device is activated, a normal mode is displayed on a screen of a monitor. An operator presses a manual mode switch key of an operation unit to switch the display mode of the screen from the normal mode to an extension pattern manual rearrangement mode. In the extension pattern manual rearrangement mode, the operator rearranges extension patterns so that frequently selected extension patterns P may be displayed at upper positions. Thus, the frequently selected extension patterns P are more preferentially displayed than the other extension patterns P.

A user-friendly crane mat carrier is provided for conveniently transporting, storing and supporting crane mats, pads and other items. The economical light weight crane mat assembly can comprise a frame assembly with a main load-supporting bar, crossbars and perimeter bars. The special crane mat carrier can be easily connected to a crane, such as with a drawbar fixture, securing plate and locking plate. A hanger assembly with a suspension bar can be provided to hang the crane mat carrier. A latch mechanism can also be provided to securely lock the crane mat carrier.

Various embodiments of the present invention provide adjustable pit liners for use in conjunction with pipelines installed underground. The pit liners provide surface access to devices in fluid communication with the pipeline. The adjustability of the pit liners facilitates installation of the pit liners before the final grade surrounding the pit is known. In various embodiments, a tubular structure having an upper section and a lower section is provided, wherein the upper section and the lower section are slideably connected in a telescoping relationship. A locking mechanism is also provided to releaseably lock the overall height of the tubular structure as desired.

Embodiments of chemical delivery systems disclosed herein may include an enclosure; a first compartment disposed within the enclosure and having a plurality of first conduits to carry a first set of chemical species, the first compartment further having a first draw opening and a first exhaust opening to facilitate flow of a purge gas through the first compartment; and a second compartment disposed within the enclosure and having a plurality of second conduits to carry a second set of chemical species, the second compartment further having a second draw opening and a second exhaust opening to facilitate flow of the purge gas through the second compartment, wherein the first set of chemical species is different than the second set of chemical species, and wherein a draw velocity of the purge gas through the second compartment is higher than the draw velocity of the purge gas through the first compartment.

A valve unit includes a valve member that moves relative to a valve seat in response to a magnetic field generated by a coil. An input signal to the coil controls the extent of movement of the valve member relative to the valve seat, to control a gas flow rate therethrough. The gas valve unit also includes a setting adjustment device that provides a setting adjustment input utilized for calibrating or adjusting at least one gas flow rate. A valve controller is configured to receive an activation signal and to responsively send an input signal to the coil to move the valve member and establish at least one desired gas flow rate corresponding to the activation signal, wherein the valve controller is configured to adjust the input signal to the coil based on the setting adjustment input, to thereby enable field adjustment of at least one gas flow rate.

A damper system may include a handle mechanism for use with a damper actuator system. Illustratively, the handle mechanism may include a drive gear mechanism, a handle, a housing, and a spring, and may be actuated to set a crack pressure for the damper system. The handle may connect to the drive gear mechanism at a drive gear arm of the drive gear mechanism and may flip over or about the drive gear arm to move from a first position to a second position. In some instances, once the handle is in the second position, a force may be applied thereto to disengage the drive gear from a stop member and thereafter, the handle may be rotated to change the crack pressure of the damper system.

An arrangement for testing a fire suppression sprinkler system includes a supply conduit for supplying a fire suppression fluid to a plurality of sprinklers. A sensor senses a flow of fire suppression fluid through the supply conduit. A drain conduit drains fire suppression fluid when the fire suppression system is tested. A drain valve controls the flow of the fire suppression fluid so that when the fire suppression system is tested the fire suppression fluid is controlled to enter the drain conduit. A fire suppression fluid collection tank collects the fire suppression fluid which has entered the drain conduit for reintroducing the collected fire suppression fluid to the supply conduit. A circulation valve controls the flow of the fire suppression fluid so that when the fire suppression system is tested the fire suppression fluid enters the fire suppression fluid collection tank.

The invention relates to a liquid supply system wherein liquid, such as for example, a supply of warm water, circulates. Said system consists of thick outer tubes, the inner chamber of said thick outer tubes allowing a liquid to flow through, a thin inner tube is respectively placed inside the outer tube in which the liquid can flow in the direction counter to that in the inner chamber. In the path of at least one outer tube, a first tube branch is introduced enabling the first inner tube to be withdrawn, and in said first branch, at least one functional component, such as a shut-off valve, is introduced into the inner tube and guided to a second tube branch in the path of an outer tube and extends further through said tube branch and then into the inner chamber of the latter outer tube.

A shaft sealing device switches a sealing state and an unsealing state of a fluid, with high sealing performance maintained, because no abrasion accompanies movement of a sealing material or a sealing member, enabling feeding a fluid at a predetermined flow rate, and adjusts the expanding rate of the sealing material with the quantity of an external electric signal and accordingly adjusts the contact face pressure to enable controlling the amount of leakage of the fluid highly precisely, so that it can be used for all applications. The shaft sealing device includes a shaft sealing body formed of a macromolecular material and made expansible or contractible, or deformable, through external electrostimuli applied to a shaft sealing portion disposed in a device body, and flow passages disposed in the shaft sealing portion for feeding the fluid leaked due to the expansion or contraction, or the deformation, of the shaft sealing body.

A fluid coupling includes a socket with a socket main body, a fixed valve, a guide which is engaged with the fixed valve and biased to be pressed against an inner surface of the socket main body, and a guide spring which biases the guide, and a plug with a plug main body, a movable valve, a valve spring, and a valve holder which supports the movable valve and the valve spring. When the plug is inserted into the socket, the guide moves rearward against a biasing force of the guide spring to connect a flow path between the plug and the socket. A fitted portion, which is fitted into the distal end of the plug, is disposed at the end portion of the guide. First seal members are disposed between the fitted portion and a distal end of the plug.

A rotary distributor device for a hydraulic power steering, which receives oil from a pump and sends the oil selectively to a discharge or to an actuator of the steering in a desired direction, comprises a jacket, a slide, sealedly rotating in the jacket, a series of openings that cross the wall of the jacket, located in front of a series of corresponding openings which cross the wall of the slide, elastic member located between the jacket and the slide configured to maintain the openings of the jacket at the openings of the slide, in which each opening in the jacket includes, in succession starting from the outside, at least one radial hole, a slot lying in a radial plane, arranged symmetrically with respect to the axis of the hole, the width being smaller than the diameter of the hole, and the depth being such as to intersect the hole.

A one-handle valve cartridge has a low point of contact for installing the valve cartridge in a valve body. A retention nut bears down on the low point of contact to secure the valve cartridge in the valve body.

A water divider includes a water divider shell with openings formed on two ends and sides. A fixed water dividing device and a rotated water dividing device are provided within the water divider shell. A first through hole extends between the side and the bottom end of the fixed water dividing device, the side through hole opening position of the first through hole corresponds to the position of the opening provided on the side of the water divider shell. A second through hole extends between the top end and the bottom end of the fixed water dividing device, the top end through hole opening of the second through hole corresponds to the top end opening of the water divider shell. The rotated water dividing device includes a third though hole having a through hole opening that corresponds to the bottom end opening of the water divider shell.

To improve operability of a switching operation and locking operation of an operation pattern switching valve for switching the operation pattern of controlling devices for actuator control valves. An operation pattern switching device has a rotating operation member that rotates around a shaft center of a rotating support shaft, and thereby performs a switching operation of the operation pattern switching valve; and an operation lever that is provided rotatably integrally with the rotating operation member and performs a rotating operation of the rotating operation member. The rotating support shaft is, at each pattern switching position of the operation pattern switching valve, in a circumferential direction, provided with a plurality of lock engagement parts each with which the operation lever engages. The operation lever moves in a direction orthogonal to the shaft center of the rotating support shaft, and be thereby made engageable/removable with/from each of the lock engagement parts.

A device for vibrating tubing as it is inserted into a wellbore is disclosed. The device has a fluidic switch that has no moving parts. The fluidic switch is connected to a piston that oscillates back and forth in a cylinder. The piston is the only moving part. As the piston oscillates, it blocks and unblocks openings in the cylinder or other components. The movement of the piston controls the timing of the oscillation, and also generates an impulse or vibration. The vibration may reduce the friction between the tubing and the wellbore.

A substrate of a lab-on-a-chip system has two adjacent recesses, one serving as a flow channel and the other one being filled with an elastomer compound. In a first state, the elastomer compound and the substrate delimit the flow channel in a section. In a second state, the elastomer compound takes up the space in the recess in the substrate along a cross-section of the flow channel, thereby completely closing the flow channel. The substrate and the elastomer compound may be produced by injection molding techniques.

In a fluid control device, a check valve includes a first valve housing and a first diaphragm. The first diaphragm defines a first valve chamber and a second valve chamber. An exhaust valve includes a second valve housing and a second diaphragm. The second diaphragm defines a third valve chamber and a fourth valve chamber. The check valve is opened and closed by a difference in pressure between the first valve chamber and the second valve chamber. The exhaust valve is opened and closed by a difference in pressure between the third valve chamber and the fourth valve chamber.

The Invention provided is a hydraulic powered down hole reciprocating pump traveling valve component to provided lifting hydraulics on the down stroke using the derived motion and pressure of petroleum liquids and gasses, such as oil, water and natural gas and also utilizing the frictional traveling forces driven by the surface equipment. Designed to utilize the elements within the pumping apparatus to obtain the hydraulic power within and transfer the energy's force to the exposed bottom end of the pressure locked traveling ball valve adjacent within the ball valve containment cage, providing ultimate lifting power to open the ball valve on the initiation of the down stroke. The component consist of a Hollow Hydraulic Power Shaft, Hollow Pressure Motion House, and a Fluid Cavity Power Drag Plunger.

In the method and apparatus of the invention, the process point is taken into account when the condition and performance of a control valve are monitored. In the condition monitoring of the valve, process measurements are used in addition to measurements inside the valve in such a manner that the process measurements identify the operating point at which the valve operates, and the measurements inside the valve are observed at these operating points to detect changes and to determine the condition of the valve. According to an aspect of the invention, the variables representing the operating point of an industrial process are considered when changes in the friction load of the valve and/or the load factor of the actuator are observed.

Disclosed herein is an improved method for reversed flow through a self-adjustable (autonomous) valve or flow control device (2), comprising the step of providing an overpressure on the side of the valve (2) opposite of the side of the inlet (10) exceeding a predetermined biasing force of the resilient member (24) causing lifting of the inner body part (4a) within the outer body part (4b) against said biasing force from a first position of fluid flow between an inner and an outer side of the valve (2) via the flow path (11) and to a second position of reversed fluid flow between said inner and outer side through the second flow path (25). An improved self-adjustable (autonomous) valve or flow control device (2) and use of said improved valve or flow control device are also disclosed.

In one implementation, a method for providing a fluid at a target pressure may include providing a fluid at a velocity to a supply line through a dispenser, measuring a pressure of the fluid flowing through the supply line, comparing the measured pressure with the target pressure, and adjusting the velocity based on the results of the comparison.

A switching valve contains a sleeve member, a plug member, and a damping spring. The sleeve member includes a watering segment, a spraying segment, a peripheral fence, a side fence, a channel, a first watering chamber, and a second watering chamber. The peripheral fence has a first valve seat, a second valve seat, and at least one set of inlet. The first valve seat has a conical first closing face and a plurality of stop blocks. The second valve seat has a conical second closing face. The plug member includes a first sealing portion, a second sealing portion, and guiding ribs. The first sealing portion has a first ring, and the second sealing portion has a second ring. Each guiding rib has a guide face, and between any two adjacent guiding ribs is defined a slot. The damping spring is mounted between the side fence and the plug member.