Abstract: A steering gear assembly with a pinion shaft, rack, housing and rack bearing. A biasing assembly biases the rack bearing against the rack and into engagement with the pinion. The biasing assembly includes a gross adjustment member secured to the housing, a bearing assembly with a bearing member coupled with the rack bearing and a first adjustment member. A first biasing member is coupled with the bearing member and first adjustment member which are relatively moveable to thereby define a compliance zone to allow for dimensional variations in the meshing of the rack and pinion. An adjustment biasing assembly is operably disposed between the gross adjustment member and the bearing assembly. The adjustment biasing assembly is disposed entirely within the housing, includes a second biasing member, and urges the first adjustment member toward the rack bearing in continuously-variable axial movements while preventing movement away from the rack bearing.

Abstract: Embodiments of the present invention relate generally to methods and systems for an active tracking solar panel racks.

Abstract: A shift lever assembly utilizing a single switch to produce a first signal indicating that a transmission of a vehicle is in a park position and a second signal to authorize removal of a key from an ignition of the vehicle is disclosed. The switch includes a casing supporting a plunger having a first park indication contact and a first key removal contact. The casing includes a second park indication contact and a second key removal contact. The first park indication contact engages the second park indication contact when the plunger is in a rest position and is disengaged from the second park indication contact when the plunger is in a depressed position. The first key removal contact is disengaged from the second key removal contact when the plunger is in the rest position and engages the second key removal contact when the plunger is in the depressed position.

Abstract: A gearshift interlock is provided including a first shift block operatively associated with a first synchronized gear. The first shift block is movable between neutral and actuated positions and has a detent. A second shift block is provided operatively associated with a second synchronized gear. The second shift block is movable between neutral and actuated positions and has a detent. A lockout member is provided wherein movement of one of the shift blocks from the neutral position toward the actuated position causes that shift block to urge the lockout member to engage the other shift block detent preventing movement of the other shift block.

Abstract: A gear shift assembly includes a base, a cylindrical collar extending from the base, a shift rod having generally spherical tip at a first end thereof for engaging a corresponding socket of a transmission, inner and outer gimbal spheres mounted on the shift rod and supported in the collar whereby the outer truncated gimbal sphere may pivot in the collar in a first direction when the shift rod is moved in the first direction and wherein the inner gimbal sphere is supported in the outer truncated gimbal sphere whereby the inner gimbal sphere may pivot inside the outer truncated gimbal sphere in a second direction substantially perpendicular to the first direction when the shift rod is moved in the second direction.

Abstract: Provided is an adjustable pedal system. The adjustable pedal system includes: a support bracket having a predetermined hole and a guide groove which are substantially perpendicular; a driving part including a driving arm which can make a substantially vertical motion along the guide groove and provides a driving force to the driving arm; a control arm including a hinge hole which is coupled to the driving arm by a first pin and a sliding slot which is coupled to the predetermined hole by a second pin and formed oblique to the guide groove; and a pedal arm having a pedal at one end thereof and being connected to the control arm at other end thereof, the control arm slides obliquely along the sliding slot according to the working of the driving arm when moves vertically along the guide groove and thus this causes a position of each of the control arm and the pedal arm to be changed.

Abstract: A vehicular handlebar grip includes a central portion, a grip portion, and a support portion. The central portion includes a first end and a second end. The grip portion is located at one side of the central portion, extending toward a direction away from a long axis extending from the first end toward the second end. The support portion is located an opposite side of the central portion relative to the grip portion, extending toward a direction away from the long axis. Accordingly, when the vehicular handlebar grip is applied to a bicycle, the cyclist can adjust the contact area where the wrist lies against the support portion according to the cyclist's different riding postures to allow more space for movement of the palm for more comfortableness.

Abstract: A steering wheel for a vehicle includes a circular member operated by a driver of the vehicle to control a steering shaft mounted for rotation inside a steering column, the free end of which is fitted with a box body for housing an air bag and having at least one control lever.

Abstract: The invention relates to an actuator for a wheel guiding element of motor vehicle wheel suspensions, with a first, preferably electrically driven actuating drive which selectively changes the length of the wheel guiding element, in the actuator there being a compensation spring which counteracts the compressive forces acting on the wheel guiding element. According to the invention, the pretensioning force of the compensation spring can be changed by means of a second, preferably electrically driven actuating drive.

Abstract: Discloses is a method an system for vibrating an object using centrifugal forces, wherein said centrifugal forces is achieved from a rotating device and wherein said centrifugal forces comprises a positive force and a negative force. A linear motion is added to said rotating device thereby inverting said negative force of said centrifugal forces to a positive force.

Abstract: A process of water-granulating copper smelting slag can readily suppress elution of As from the copper smelting slag. A process of water-granulating a copper smelting slag with granulation water in a circulating system, includes granulating the copper smelting slag with the granulation water; settling suspended solids from the granulation water circulating in the system in a settling tank followed by discharging part of the granulation water through the settling tank from the system; and feeding supplementary water having a concentration of As of 0.01 mg/L or less into the system in such an amount that the total amount of the granulation water circulating in the system is kept constant; wherein the amount of granulation water discharged through the settling tank is such that As eluted from the copper smelting slag after water granulation is 0.01 mg/L or less.

Abstract: A method is provided for recovering rhenium from a titania-supported, rhenium-containing catalyst by treating the catalyst in the reduced form with an acid in an amount and for a time sufficient to dissolve the rhenium without dissolving the support.

Abstract: A fluid operated torque tool tightens a nut through a spring washer on a plate on a railroad crossing, and has a housing, two coaxial drives applying equal turning forces in opposite directions around an axis, with one of the two coaxial drives located around the other of the two coaxial drives, a first socket attached to the one coaxial drive and configured to fit on the rectangular plate, and a second socket attached to the other coaxial drive inside the first socket and configured to fit on the nut, with the washer being not engaged by the sockets, so as to tighten the nut and to tighten up the spring washer onto the plate while the first socket and the housing stand still.

Abstract: The present invention provides a wrench socket assembly. The socket assembly includes an anchor pin and a socket. The anchor pin can be fixed in the socket or can be pulled slightly from the socket to sway at a predetermined range when in use.

Abstract: A multi-angle tool handle includes a handle device including a compartment longitudinally formed therein, a through-hole formed thereon and communication with the compartment and an embedding portion defined in the compartment, an interconnecting element disposed in the compartment and including a pivoting end formed on an end thereof and having an embedding portion, a locking device installed in the through-hole and including an embedded end defined on an end thereof, and a connecting device pivotally coupled to another end of the interconnecting element. The locking device is moveable between a first position and a second position, therefore, the connecting device can be operated to pivot relative to the handle device or not.

Abstract: A multi-angle tool handle including a handle device, a connecting device and a locking unit adapted for connecting an interconnecting element to the handle device. The locking unit is moveable between a first position and a second position. When the locking unit is in the first position, the interconnecting element is able to pivot and slide with respect to the handle device. And when the locking unit is in the second position, the interconnecting element is fixed with respect to the handle device in position.

Abstract: An adapter engagable in a hole of a driving end of a tool includes a body receivable in the hole. The body includes a cavity in which an elastic member and a cover can be received. The elastic element can provide a force for pushing the cover to abut against the wall of the hole such that the adapter is securely retained in the hole.

Abstract: A c-clamp locking device has been specially modified to depress brake drum springs while the brake shoes are replaced. The device has opposing c-clamp jaws, one of which has a blunt end for compression against the surface of the brake drum, and the other of which has a ring for compressing the brake drum spring. The jaws are adjustable relative to each other. A locking mechanism enables the device to lock in place when the brake drum spring is appropriately compressed, allowing the mechanic to use both hands unencumbered when replacing brake shoes.

Abstract: A gripping device comprising a first arm pivotally connected to a second arm. The arms form a gripping area. A linkage mechanism is used for adjusting the inwardly and outwardly movement of the gripping area, with the linkage mechanism pivotally connected to the first arm and second arm. The linkage mechanism is formed of a first linkage laterally and pivotally connected to a second linkage.

Abstract: [Problems] To provide a cutting tool consisting of a hard material improved in the adherence between a substratum of cemented carbide having hard phases bound by a binder metal and a TiN layer superimposed on a surface of the substratum, and provide a process for producing the same. [Means for Solving Problems] There is provided a cutting tool consisting of a hard material, characterized in that the hard material has a substratum containing hard phases and a binder metal and a TiN layer superimposed on a surface of the substratum, and that the substratum has ?-phases consisting of at least one solid solution of carbide, nitride or carbonitride containing W and at least one member selected from among Ti, Ta, Nb and Zr, and that at least some of the ?-phases lie at a surface of the substratum, and that the TiN layer has crystals with the same orientation relationship as that of ?-phase crystals just above the ?-phases of the substratum surface.

Abstract: A plate workpiece processing method for obtaining at least two workpiece cut-outs from a plate workpiece. The method includes utilizing one or more cutting devices of a machine tool to perform a first cutting operation and a second cutting operation on a plate workpiece. During the first cutting operation, with the plate workpiece moving relative to the cutting device or cutting devices used for the first cutting operation, at least two workpiece cut-outs are partially formed in the plate workpiece with only a common residual connection being left that jointly connects the partially formed workpiece cut-outs to a remaining portion of the plate workpiece and that is shortened along one or more cutting lines of the second cutting operation to a size that fits within a working area of the cutting device or cutting devices used for the second cutting operation.

Abstract: A main pipe is lined using a pipe lining material that blocks the opening of a lateral pipe branching from the main pipe. An in-pipe work robot is provided with a cutting nozzle for spraying a pressurized fluid material or pressurized granular material onto the pipe lining material of the main pipe. The cutting nozzle is moved to a predetermined position inside the main pipe and rotated about a vertical axis by a rotary mechanism to cut the lining material between the first and second pipes by the pressurized fluid material or pressurized granular material sprayed from the cutting nozzle in order to form an opening for communicating the main pipe with the lateral pipe. The cutting nozzle can be moved in desired positions to drill holes accurately without damaging the internal peripheral surface of the lateral pipe.

Abstract: A cutting apparatus cuts a lateral wall of a manhole to form a hole on the lateral wall of the manhole. A circular pipe is harmonized with a main pipe and fixedly disposed therein. A rotary ring configured so as to be able to rotate along the periphery of an opening in the manhole about the axial center of the main pipe is mounted on the circular pipe. A pressurized fluid material or pressurized granular material is sprayed from a nozzle held in the rotary ring. The rotary ring is rotated and the lateral wall of the manhole is cut through along the periphery of the opening in the manhole by the fluid material or granular material sprayed from the nozzle. Since the cut portion is shaped as a circle symmetrical about the axial center of the main pipe, it is possible to form a circularly shaped cut-through part centered along the periphery of the opening in the manhole without accidentally breaking or damaging the lateral wall thereof.

Abstract: A power tool for cutting a workpiece including a casing, an auxiliary handle assembly extending from the casing, a motor disposed at least partially in the casing, and a drive transmission operably coupled to the motor. The drive transmission outputs a driving force in response to an input from the motor. A spindle locking mechanism is provided that is selectively positionable between a retracted position spaced apart from the drive transmission and a locked position engaging the drive transmission. The spindle lock mechanism thereby prevents rotation of the drive transmission in response to actuation of a pad member. The pad member can be positioned adjacent to the auxiliary handle to permit single-handed holding of the power tool and actuation of the pad member.

Abstract: The present invention relates to a rotational cutting machine, it has a base, on the base is first motive power source to bring the cutting blade rotate; near the cutting blade is a fixing tool that tightly holds an object to be cut, on the side the fixing tool is a second motive power source to turn the fixing tool together with the object to be cut; the fixing tool is set on a platform that is adjustable; when cutting an object, the first motive power source turns the blade rotate, while the second motive power source also turns the object to be cut rotate, through the platform that is movable, the fixing tool is moved towards the cutting blade, such that the object tightly held in the fixing tool can be in contact with the cutting blade, the object then can be cut efficiently and accurately.

Abstract: A miter saw having a securable positioning structure for a blade guard thereof includes a saw blade, a rotatable handle, a movable blade guard, a control unit, a positioning unit, and a rope. The rotatable handle is provided for the user's holding for the cutting operation. The movable blade guard is shiftable between where it covers the saw blade and where it does not cover the saw blade. The control unit is mounted to the rotatable handle. The positioning unit is provided for blocking the movement of the movable blade guard. The rope is connected with the control unit and the positioning unit. Accordingly, the user only needs to operate the control unit to drive action of the positioning unit via the rope to hold the movable blade guard in position, thus securing the safety of the operation. In addition, the rotatable handle can be turned smoothly without any barrier.

Abstract: A workpiece feeding device used in a saw machine is disclosed to include a carrier having a base frame movably mounted on the machine base of the saw machine and an angle scale fastened to the base frame, a fence unit having a rip fence pivotally mounted on the base frame of the carrier and biasable relative to the angle scale, a magnetic plate assembly mounted on the base frame of the carrier and carrying a magnetic strip, and a magnetic sensor mounted in the fence unit and movable with the fence unit to measure the biasing angle of the fence unit relative to the angle scale subject to change of magnetic induction between the magnetic sensor and the magnetic strip.

Abstract: A paper punch includes a base with a plurality of frames connected thereto and each frame includes a punch head biased by a spring, the top ends of the punch heads protrude from tops of the frames. A support part is fixed to the base and includes a plurality of connection plates to which an arm, a first link and a second link are respectively connected thereto. The top ends of the punch heads movably extend through the through holes in the support part. The arm includes an elongate recess and two respective rolling ends of the first and second links are movably engaged with the elongate recess. When pivoting the arm downward, the three top ends of the punch heads are respectively pushed by the arm, the first like and the second link.

Abstract: The invention relates to a circular saw blade comprising a support body (1) and a plurality of cutting teeth (2) distributed over the circumference, in which the support body (1) has a plurality of material recesses (3) that in some areas have clearing edges (4) that project axially beyond the support body (1), which is characterized in that the clearing edges (4) are embodied in one piece with the support body (1).

Abstract: A piano hammer comprises an elongate hammerhead having a nose portion defining side surfaces and a felt covering extending about the nose portion with tail portions of the felt covering affixed to the side surfaces. The felt covering defines a substantially elliptical peripheral surface from a top region for striking a piano string to front and back regions. An elongated single or dual layer strip is arranged on the peripheral surface of the felt covering in the top region, extending along the front and back regions to points beyond the hammer equator. The layers of this strip or “voicing tape” are made of a synthetic non-woven fabric material, preferably of the type sold under the registered trademark Pellon.

Abstract: For achieving a high tuning stability and a clear and radiant sound it is provided in a musical string (1), especially for plucked and/or stringed instruments, with the musical string (1) having at least one core (2) and with the musical string (1) having at least one sheathing (3) which is arranged about the first core (2), that the core comprises a predeterminable plurality of plastic cm 1 fibers (4).

Abstract: A fluid user interface is presented for applications such as immersive multimedia. In one embodiment, one or more sprays or jets create an immersive multimedia environment in which a participant can interact within the immersive multimedia environment by blocking, partially blocking, diverting, or otherwise engaging with a fluid, to create computational input. When the fluid is air, a keyboard can be implemented on cushions of air coming out of various nozzles or jets. When the fluid is water, the invention may be used in environments such as showers, baths, hot tubs, waterplay areas, gardens, and the like to create a fun, playful, or wet user-interface. In some embodiments, the spraying is computationally controlled, so that the spray creates a tactile user-interface for the control of such devices as new musical instruments. These may be installed in public fountains to result in a fluid user interface to music by playing in the fountains.

Abstract: Snare drum assemblies, including assemblies with flexible snare anchors, and associated methods are described. A drum assembly in accordance with one embodiment includes a set of snare strands, each having a first end and a second end, a first, flexible snare anchor connected directly to the snare strands toward the first ends, and a second, flexible snare anchor connected directly to the snare strands towards the second ends. The snare anchors can be flexible between a first shape and a second shape different than the first shape when attaching the snare anchors to a drum. The first and second snare anchors can have generally flat, uniform shapes when not under tension, and can have a relatively thin profile (e.g., thickness) to provide for contact between the snare strands and a drum head in one or more orientations. In further particular embodiments, the drum head against which the snare assembly is positioned need not include snare beds.

Abstract: A piano key assembly for a pianoforte in which weights are mounted on a keystick to have a center of gravity between a first point along said keystick halfway between the pivot point of the keystick and the end struck by the pianist and a second point halfway between the pivot point and the first point and wherein all the weights are located relative to the keystick between the pivot point and the first point. Optionally, holes are made in the keystick between the first point and the end struck by the pianist.

Abstract: The present disclosure relates to a system and method for visualization of music and other sounds using note extraction. In one embodiment, the twelve notes of an octave are labeled around a circle. Raw audio information is fed into the system, whereby the system applies note extraction techniques to isolate the musical notes in a particular passage. The intervals between the notes are then visualized by displaying a line between the labels corresponding to the note labels on the circle. In some embodiments, the lines representing the intervals are color coded with a different color for each of the six intervals. In other embodiments, the music and other sounds are visualized upon a helix that allows an indication of absolute frequency to be displayed for each note or sound.

Abstract: The present disclosure relates to a system and method for visualization of precise levels of measurement. In one embodiment, labels are placed around the perimeter of a circle. The difference between a target quantity and a measured quantity is visualized by displaying a line between two of the labels. In some embodiments, the lines representing the intervals are color coded with a different color for each of a chosen set of intervals. In other embodiments, a series of concentric circles are used, with the color within each circle indicating a level of measurement within a given range of measurement.

Abstract: At a time T0, prior read reproduction is started with a volume of 0. Upon starting the prior read reproduction, MIDI events containing note events are sequentially generated. Each time each of the note events is generated, note data is generated based on these note events and sequentially stored in a note pool 123. At a time T1, actual reproduction is started. After the time T1, the actual reproduction and the prior read reproduction are concurrently performed at a same speed. Accordingly, the prior read reproduction precedes invariably two bars ahead of the actual reproduction. Information pertinent to notes contained in apart from a currently played position to a position two bars ahead of the currently played position can be easily obtained from the note pool 123.

Abstract: An electronic musical sound generator prevents a sound production sequence to be stopped from continuing to be produced even through the key is released. Even if an erroneous instruction is sent to prevent identification data from being compared, in other words, if a sound production sequence which should be stopped, continues to be produced because of failure to find the sound production sequence to be stopped, the production of the musical sound can be stopped due to the key release because a second decision block searches data in a storage block, regards a key having identification data different from the one sent as the released key, according to the sequence being produced and the key is number, and determines the sound production sequence to be stopped.

Abstract: A computer program makes a computer perform: a measuring process of measuring a beat rate, which is the number of beats of content per unit time; a first detecting process of detecting a beat position; a generating process of generating a beat guide which is to be displayed in accordance with the beat position and which has a substantially uniform interval in accordance with the beat rate along a time axis, on the basis of the beat rate and the beat position; a second detecting process of detecting a positional shift between the beat guide and the beat position; an offset process of adding an offset to a position of the beat guide on the basis of the positional shift; and a displaying process of displaying the beat guide to which the offset is added.

Abstract: An electromagnetic field pickup (10) for a musical instrument including an electromagnetic signal generator (12), an electromagnetic field transducer (18), a mixer (28), the electromagnetic signal generator (12), the electromagnetic field transducer (18) and the mixer (28) are respectively connected in series, the electromagnetic signal generator (12) is also connected directly to the mixer (28), so constructed and arranged that when power is supplied to the electromagnetic field pickup (10) an audio electrical signal of substantially same pitch, intonation and sustain as a vibrating element (22) of the instrument is generated.

Abstract: A method is disclosed for providing an observer with an intuitive sense of the tactical situation in an operational area that surrounds a point-of-interest. The observer is simultaneously presented a top-down view of the operational area that includes contact indicators for each of one or more contacts within the operational area, and a status display that indicates the instantaneous hostility assessment of one or more of these contacts. In addition, the operator is automatically presented historical information, including contact images, for each contact whose hostility assessment exceeds a threshold level. The operator, or a group of operators, is enabled to view all of the displayed information from a single vantage point, assess the relative hostility of numerous contacts simultaneously, and rapidly confirm the identity of apparently hostile contacts prior to engagement.

Abstract: A method of deactivating land mines buried in ground comprises projecting high-pressure water jets into ground, cutting through ground with the high-pressure water jets, and making at least one cut through a land mine or cutting through at least one land mine that had been under the ground, the cutting of the land mine reducing the performance of the land mine. The method may reduce the performance of the land mine by rendering the land mine inactive to normal detonation procedures for the land mine. To reach as many surface areas on the buried landmines, it is preferable that at least two high-pressure water jets are spaced apart are used to cut through the ground. The method may be practiced with the high-pressure water jet being carried on a vehicle and cutting is done in a line that is formed at least in part by movement of the vehicle over the ground while the high-pressure water jet is cutting ground.

Abstract: A missile launching system including a launch rail for attachment to an aircraft and having a longitudinal slot, and at least two hangers for attachment to the missile at longitudinally spaced locations thereof and having a cross-section configured to be received in the longitudinal slot in the launch rail. The rearmost hanger includes two separable main parts, including a first main part for engagement with a respective lateral, first groove section of the slot, and a second main part configured to be attached to the missile and be slidably guided in a second groove section of the slot normal to the first groove section and opening towards the missile. The second main part includes laterally extending collars configured to interact in close proximity with respective rail sections facing the missile. The second main part is configured to separate from the first part when launching the missile.

Abstract: A kit for modifying a bolt carrier group actuating apparatus of a firearm manufacturer-configured with a gas-driven bolt carrier comprises a gas expansion assembly, an operating rod driven bolt carrier and an operating rod. The gas expansion assembly is configured for receiving combustion gases from an as-manufactured OEM gas block of the firearm and for facilitating expansion of said gases for generating a bolt carrier driving force. The operating rod driven bolt carrier includes an operating rod engaging lug. The operating rod driven bolt carrier is configured for being operably engaged within an as-manufactured OEM receiver body of the firearm with the operating rod engaging lug located in a gas tube lug receiving portion of the as-manufactured OEM receiver body. The operating rod is engagable between the gas expansion assembly and the operating rod engaging lug.

Abstract: A method of calibrating an electrically actuated hydraulic valve in a system that controls the flow of hydraulic fluid to a hydraulic cylinder connected to a machine element operates automatically. The system includes an ultrasonic sensor providing an indication of the position of the machine element. The calibration method includes the step of automatically applying a command signal to the hydraulic valve while monitoring the ultrasonic sensor to determine the level of the command signal required to cause the hydraulic cylinder to begin to move. The calibration method includes the additional step of automatically applying in succession a plurality of command signals of increasing level to the hydraulic valve while monitoring the ultrasonic sensor to determine the speed of movement of the hydraulic cylinder resulting from each of the command signals.

Abstract: A hydraulic machine has a plurality of pistons reciprocating within corresponding cylinders. Embodiments may operate as a pump, a motor, or both. The hydraulic machine can be configured to selectively disengage certain pistons from the cam to operate at less than full displacement. This provides a discrete variable displacement machine. The hydraulic machine can also be configured to provide a type of continuously variable displacement by changing the high and low pressure port connections to the cylinders at different positions of the pistons' stroke—i.e., positions other than TDC and BDC. To inhibit hydraulic lock when continuously variable displacement is used, the closing and opening of the high and low pressure ports are allowed to overlap; however, a barrier is used to inhibit short circuiting the fluid between the ports. Individual cylinders can be provided with relief valves to further inhibit hydraulic lock.

Abstract: An actuator includes a cylinder, a piston rod which moves forwards within the cylinder and a lock mechanism for restricting a backward movement of the piston rod that has moved forwards. The piston rod includes a piston portion and a support rod portion which is made to extend from the piston portion. The lock mechanism includes an annular elastic element which is disposed with an inner circumferential edge made to project further radially inwards than an inner circumferential surface of the cylinder and a groove which is disposed so as to extend along an outer circumferential surface of the piston portion for the annular elastic element to be fitted therein.

Abstract: A fluid pressure type actuator revolvable at high speeds and an exercise device using the actuator. The fluid pressure type actuator comprises an expansible/contractible body (1), which is sealed by plug members (2,3) at both ends and expanded and contracted by the supply and discharge of a fluid there to and therefrom, a net-like wrapping body (7) which wraps the outside of the expansible/contractible body (1) and is fastened and secured to the plug members (2,3) at both ends, and inlet and outlet for fluid formed in the plug members (2,3). It is characterized in having space reducing bodies (4,5) for filling at least a part of a space in the expansible/contractible body (1).

Abstract: A torque transfer arrangement includes a relatively immobile construct; a relatively mobile construct radially adjacent the relatively immobile construct; and one or more torque valve assemblies mounted to the relatively mobile construct and radially responsive to applied hydraulic pressure to contact a surface of a separate structure and transmit torque from the arrangement to the separate structure and method.

Abstract: The present invention discloses a piston device which is disposed in a cylinder. The cylinder has a chamber including a bore and an inner wall. The piston device comprises a piston body and at least an annular ring. The piston body has a top side and a bottom side, the diameter of the piston body is smaller than the bore, and either one of the top side or the bottom side has a convex portion. The annular ring is clamped to the top side or the bottom side by engaging said convex portion, and the annular ring has a diameter slightly larger than the diameter of the piston body. While said piston therein moves reciprocally at which the axial direction of the cylinder, the annular ring slides against the inner wall but the piston body has no contact with said inner wall.