Abstract: An emergency floatation system for a helicopter includes a safety trigger device for inflating at least one raft during the course of an emergency. The safety trigger device includes a plurality of handles such that pulling any one of the plurality of handles triggers the inflation of the at least one raft.

Abstract: A power/data bus for conducting at least one of data and power signals to a variety of different locations on a mobile platform. The bus has a plurality of discrete connection ports, and at least one conductive cable. The power/data bus extends across an area where access to at least one of data and electricity is desired. The discrete connection ports are spaced apart at different locations along the power/data bus. The conductive cable extends through the power/data bus and is connected to at least one of the discrete connection ports. The conductive cable conducts at least one of power and data signals between the discrete connection ports and a data/power source. At least one of the connection ports are operable to cooperate with a connector of an external device to supply at least one of power and data signals to the external device. The power/data bus, when used in an aircraft passenger cabin, eliminates the need to extend individual data and/or power cables to or between each passenger seat group.

Abstract: An apparatus warns of differential pressure during the opening of a pressure-loaded door that closes an opening in an aircraft fuselage. An air guide passage extends from the side with higher pressure to the side with lower pressure. The air guide passage is closeable by a valve that is controllable with a control lever operatively Connected to a door opening mechanism. When there is a differential pressure between the two sides, upon opening of the valve the apparatus produces an acoustic signal as a differential pressure indication that is independent of a supply system and serves as a warning signal for the operator of the aircraft door.

Abstract: A remotely controlled apparatus for grasping an object such as a satellite in space includes a free-flying grasper unit connected by a selectively extendable cable to an orbital platform. The orbital platform and the grasper unit are preferably each independently propelled by respective propulsion systems including multi-axis maneuvering nozzles respectively provided on the orbital platform and on the grasper unit. The grasper unit preferably includes a grasper unit body and a grasper-arm mechanism having a controllable grasping claw articulately mounted on the end of a controllable telescoping arm that extends from the grasper unit body. The grasper unit preferably further includes a camera and a distance measuring sensor to provide visual and distance feedback data for assisting the remotely controlled maneuvering of the grasper unit and actuation of the grasper-arm mechanism.

Abstract: Methods for increasing the performance of a foil (100) by using tip droop (102) having an inward directed camber capable of generating an inward directed lifting force on the tip droop (102) in order to control spanwise flow conditions adjacent the tip (112) of a foil (100). Methods for varying the inward lifting shape of a tip droop (102) are provided along with methods for varying the angle of attack and camber of the tip droop (102) as the angle of attack of the foil (100) is changed and as spanwise flow conditions vary.

Abstract: A clevis hanger assembly supports a pipe insulation coupling member along a support structure. The clevis hanger assembly includes an upper bracket adapted to be secured to the support structure. The upper bracket includes a base extending between spaced apart downwardly extending flanges. The clevis hanger assembly also includes a lower bracket having spaced apart upwardly extending flanges disposed alongside the spaced apart downwardly extending flanges. The lower bracket includes an arcuate segment extending between the spaced apart upwardly extending flanges and defines coupling slots for receiving the pipe insulation coupling member.

Abstract: A vibration suppressing clamp for pipe or the like comprises a base supporting a pipe holder with a space for accommodating a pipe to be held. The space is defined by a curved seat and a pair of walls extending from the seat. At least one of the walls is flexible, has a piece at a tip portion for holding a pipe in the space, and is spaced from an adjacent rigid wall. A vibration suppression member covers the seat and adjacent portions of each flexible wall and fills at least a portion of the space between the flexible wall and the adjacent rigid wall. The seat and the base have holes into which deformed portions of the vibration suppression member can retract in response to an impact on a pipe in the pipe holder.

Abstract: A clamp for holding of films, tape lines or the like consists of an underpart consists of a floor and stops projecting from the floor and arranged at a distance from each other, laterally bounding a holding region, and a top part attached to the underpart and opposed to the floor, an entry opening being provided between the top part and the stop arranged on one side of the holding region. The clamp comprises a lid overreaching the top part in closed position and connected to the underpart by a closure, with which lid the entry opening is closable.

Abstract: A pipe hold-down for securing a pipe to a building member includes a back having a base end, a distal end, and a fastener receiving aperture extending therethrough from the distal end to the base end. A claw extends outwardly from the back proximate the distal end thereof and curves toward the base end. A leg extends outwardly from the back proximate the base end thereof is more flexible than the back and bendable relative thereto. An opening is defined between a distal end of the claw and the leg. The leg is bendable between a normal position and a pipe admitting position wherein the leg is bent outwardly away from the claw, in the normal position the opening is substantially narrower than the outside diameter of the pipe and in the pipe admitting position the opening is at least as wide as the outside diameter of the pipe.

Abstract: A support for a medical instrument such as a binocular microscope including a plurality of piviotally connected arms connected to a wall, ceiling or vertical support mount. One of said arms being vertical and having ball joints at opposite ends, one connected to an adjacent arm and the other connected to the binocular microscope. An extension connected at one end to the binocular microscope and at an opposite end to a head harness for attaching to the head of an operator. Two of the arms are connected by a bearing having a vertical extension. One of the arms is pivotally connected to the vertical extension. A compressed gas cylinder is connected at one end to the vertical extension and at another end to the arm connected to the vertical extension. The arrangement is so that the operator can position the binocular microscope without use of any hands and with negligible resistance.

Abstract: A boom stand is constructed from a base, extensible stand, pivotal boom support, and boom. The base has arcuately segmented massive anchors that form a perimeter. The arcuately segmented massive anchors are shaped and sized to fit within the perimeter of like bases, to decrease minimum distances between stands during storage or close use, while still providing stability. Over-center clamps provided on the extensible stand are extruded to include unitary cord guides, and are engaged with tube ends to prevent rotation or accidental removal. The pivotal boom support incorporates a disc and elastomeric pads to provide superior locking and vibration reduction, and utilizes in alternative embodiments perimeter and central over-center clamps which further enhance the operation.

Abstract: An apparatus for stabilizing the legs of a tripod includes a center member that is placed inside and proximate the legs preferably about mid-length. The center member includes three perimeter assemblies that each cooperate with a corresponding leg member. The center member is secured to each leg by the leg member which is either attached to each leg or which passes around each leg and is then secured to each perimeter assembly. When each perimeter assembly is tightened, the center member is urged upwards where it pushes all of the legs outward while each leg member prevents one of the legs from moving outward. Accordingly, each leg is placed in a tension that increases its stability and hence the stability of the tripod.

Abstract: A support for geomatic equipment such as a geomatic pole has feet which facilitate stability of the pole. The feet are constructed to resist forces applied along legs of the support to which they are connected in both directions, including forces which tend to lift the feet upward. The foot is formed to readily penetrate certain surfaces and to resist withdrawal from the surfaces after penetration. In one embodiment, a fixed connection to the underlying surface may be achieved. The foot is also constructed to resist rotation of the foot and leg to which it is attached which could cause instability of the support.

Abstract: A device for mounting taxidermy mounts, especially waterfowl and other birds. The mounting device prevents the mounted object from twisting or slipping on the mount and the mounted object can be prevented from sagging. The mounting device allows for the mounting of a mounting object in any position that is desired.

Abstract: A biased-assisted sign mounting system is for mounting a sign to a structure, that includes a vertical upright post having a face having a plurality of vertically extending, spaced apart openings. The mounting system includes a spine adapted to mount to the vertical post. The spine has a face portion. Upper and lower sign mount portions are mounted to the spine. At least one of the mount portions has a biasing element securing portion. Upper and lower arms are mounted to respective upper and lower sign mount portions. The arms each have a pivot defining collinear axes. One of the upper and lower arms has a biasing element securing portion. A biasing element operably connects one of the arms to its respective mount portion such that the arm is pivotal between first and second positions and is biased toward the first and second positions by the biasing element. A floating insert mounts the spine to the upright.

Abstract: A support apparatus for suspending a display has a holder with a first end pivotally mounted on a ceiling, an arm pivotally connected to a second end of the holder, a redirector pivotally mounted on the arm, and a seat pivotally mounted on the redirector. Whereby, a display secured on the seat can be easily and smoothly adjusted in a wide extent.

Abstract: A beverage bottle holder is adapted to hold a plastic beverage bottle and comprises a bottom collar adapted to accept the bottom surface of the beverage bottle; a top grasping member adapted to exert compressive forces against the outside surface of the beverage bottle to firmly holding the bottle in a stable configuration within the bottle holder; a handle and at least one sinusoidal cusp within the inner surface of the bottom collar. The cusp is adapted to mesh with concavities within the bottom of the plastic bottle. The bottle holder is specifically designed for use in combination with plastic beverage bottles by persons with reduced hand strength and motor skills due to age, infirmities and disease.

Abstract: A leg-mounted mouse pad for use with a computer cursor control device, said mouse pad comprising a generally oval-shaped flexible platform having a bottom surface and a top surface, wherein at least a portion of said top surface is adapted for use with a computer cursor control device. At least two bilaterally opposed pockets formed adjacent a perimeter of each half of the oval shaped mouse pad, the pockets adapted to contain a weighted media suitable for positioning the flexible platform on the leg of a user, the platform being substantially flexible such that when weight is contained with the pockets, the platform substantially conforms the surface of the user's leg.

Abstract: A support for supporting a laptop computer has a top tray in cooperation with but not attached to a bottom tray. The top tray is moveable from an inclined working position to a flat storage position. The top tray has a top base having a lip proximal one end. The bottom tray has a bottom base having a flange extending upwardly proximal one end. The flange and/or the bottom base of the bottom tray has an aperture for accepting the lip of the top tray. The lip of the top tray may engage the top of the flange when the top tray is in the working position to prevent the top tray from sliding towards the opposite end of the bottom tray. The lip of the top tray engages the bottom base through the aperture when the top tray is in the storage position to limit sliding of the top tray toward the opposite end of the bottom tray. In the storage position, the support is readily packed together with the computer in the computer's carrying case.

Abstract: A locking device of a longitudinal adjustment device of a vehicle seat is provided with a catch bar with periodically arranged snap openings and snap studs that is assigned to a bottom rail of the longitudinal adjustment device and is further provided with a locking unit assigned to a seat rail of the longitudinal adjustment device. The locking device has at least two licking pins that can be inserted into the snap openings independent of one another, they can be disengaged only jointly. The locking pins are arranged in a guide member which has a pin bore for each locking pin. The guide member is provided with an area facing the catch bar. Projections projecting toward the catch bar are arranged on this area and extend as a continuation of the pin bore.

Abstract: A mount for securing an associated object such as a sign to a supporting structure having wall defining an opening therein and having an outer surface and an inner surface, includes a mounting element adapted to receive the object. The mounting element has a body having an opening therein that is defined by edges. The opening has a predetermined shape. The body has a pair of resilient fingers extending rearwardly from the body. The fingers define portions of the edges of the opening in the body. A wedge has a base and a pair of resilient legs depending from the base. The wedge has a predetermined shape adapted for receipt in the body opening. The legs each have a notch formed therein. The mounting element is positioned with the resilient fingers in the supporting structure wall opening with the fingers locked to the supporting structure wall and the wedge is received in the body opening to interfere with the mounting element fingers flexing inward, securing the mounting element to the support structure.

Abstract: The invention relates to a mounting system for fitting fixing elements on a wall. The aim of the invention is to allow easy mounting of fixing elements, in a cost-effective manner and with simple means, especially in rooms provided with tiles or similar wall coverings. For that purpose, the inventive mounting system comprises a base body constituting a fixing element and having at least one filling opening for introducing a bonding and fixing agent between the wall and the fixing element. The base body also has openings for penetration and distribution of the bonding and fixing agent. The base body and/or its back side oriented towards the wall are designed so as to be fluid- and gas permeable.

Abstract: The invention relates to a supporting device, which comprises a larger clearance for the spindle, whereby the foot receiving device should comprise a high level of stability. The foot-receiving device comprises a component, which occludes the inner sleeve. Said component comprises an opening for admitting the spindle, at least one bracing element located on the upper and/or bottom sides thereof, and two opposing bearing points for the support foot.

Abstract: A throttle body (1) includes a throttle casing (2) and a motor casing (8). The throttle casing has a first main body (3) and a throttle valve (4) disposed within the first main body. The first main body is made of resin. The motor casing (8) has a second main body (9) and a motor (11) disposed within the second main body. The first main body and the second main body are formed separately from each other and are connected to each other via a joint device (27).

Abstract: An electromagnetic actuator includes: a valve body part formed in a substantially cylindrical shape and provided with: an opening to be connected to an external fluid passage; a valve accommodated in the valve body part; and a groove having an inclined face; a solenoid part that actuates a valve; and a seal member that is fitted on an outer peripheral of the inclined face to be urged in an axial direction of the valve body part.

Abstract: An assembly for swinging an external handle of a tank dome valve on a tank dome about a generally horizontal axis has a gearbox and an air motor. In a preferred embodiment, a housing is cooperatively formed by the gearbox casing and the motor cover. The gearbox contains a worm that meshes with a gear that turns within the casing. The air motor turns the worm, thereby turning the gear. An adapter that is external to the casing has a spline that passes through an aperture in the casing to mesh with an internal spline of the gear. The adapter is shaped for engagement with the handle of the tank dome valve. The housing and adapter are arranged such that, when the adapter is in engagement with the valve handle and the motor is operated to turn the gear via the worm, the far end of the motor cover is forced to bear against the tank dome and consequently force the adapter to swing the handle.

Abstract: An automobile jack stand having four sides that substantially form a pyramid. Extending from the pyramid is a telecopying support. The telescoping support is attached to a curved horizontal support arm which is the primary point for support. Extending outward from two sides are small support arms which are equipped with light sockets. The light sockets rotate from a horizontal position to a vertical position. The lights are connected to a battery located in the base of the jack and the battery is connected to a electrical cord capable of connecting to an electrical out. The electrical cord functions to recharge the battery.

Abstract: An improved apparatus for assisting in the removal and installation of vehicle components such as doors, hoods, deck lids, bumpers and/or the like during assembly, disassembly and/or repair by using an expandable metal fixture attached to a portable engine hoist is provided. The apparatus includes a central telescoping fixture assembly formed of a plurality of parallel tubes secured together by a mounting plate on the rear face thereof. An upper telescoping tube assembly is provided comprising one or more tubes having a first end slidably engaging and extending outwardly from the central fixture assembly tubes and second ends affixed to a cross bar assembly. Also provided is a lower telescoping tube assembly comprising a tube having a first end slidably engaging and extending outwardly from a central fixture assembly tube and a second end affixed to a cross bar assembly.

Abstract: An elevator having a car and a suspension member or respectively hoisting member for carrying an operating weight. Furthermore, a power transmission is intended for moving the suspension member and the hoisting member over at least one moving surface of the power transmission. The power transmission and the suspension member or respectively hoisting member are rope-shaped and/or belt-shaped. Also, the power transmission and the suspension member or respectively hoisting member are physically separated from each other. The power transmission and the suspension member or respectively hoisting member are stretched against at least one supporting body.

Abstract: A privacy panel system for ornamental fences that include a plurality of panel members that are dimensioned to fit within adjacent pickets of the ornamental fence to close off and provide privacy between the pickets. Each panel member comprises a central section with offset attachment wings, the latter of which are affixed to the back planar face of the parallel fence pickets. The central section is offset to extend within and between adjacent pickets, but offset from the front face thereof. To provide privacy between a picket and a post, such as an end post, an elongated trim piece is provided having a first edge defining a slot with a slot gap substantially equal to the thickness of the privacy panel to enable a free edge of a central section of the privacy panel to be tightly retained within the slot. The free edge of the privacy panel is formed by cutting the central section vertically to provide a free end, which is rigidly and securely retained within the slot.

Abstract: A hydraulic damping mount, particularly to mount an automotive engine, is formed with a support spring. The support spring is produced from an elastically deformable material and supports a mount core connected to a supporting arm. The mount is provided with a working chamber, defined by the support spring and which may be filled with a hydraulic fluid. A compensation chamber is connected to the working chamber by an overflow channel. The supporting arm is detachably connected to the mount core. The mount is characterized by a relatively simple and economic embodiment as the overflow channel is integrated in the supporting arm.

Abstract: An engine mount having an upper and a lower mounting member connected by a rubber elastic body disposed therebetween, to be installed on a vehicle with a opposition direction of the upper and lower mounting member inclined with respect to a vertical, and an adjustment plate member affixed to the upper mounting member with the adjustment plate member and the lower mounting member elastically connected by the rubber elastic body disposed therebetween. An upper stopper portion is integrally formed by bending a lower end portion of the adjustment plate member toward the upper mounting member so that the upper stopper portion extends generally on a horizontal when installed on the vehicle. A lower stopper portion disposed on the lower mounting member is situated below the upper stopper portion with a gap therebetween. A bound cushion rubber is formed on the upper stopper portion and/or lower stopper portion.

Abstract: A semiconductor element holding apparatus includes a collet for suctioning a semiconductor element by negative pressure to hold the semiconductor element. The collet has a protrusion formed at the semiconductor element-holding surface thereof, and the protrusion is provided with a plurality of suction holes. The suction holes are opened to the semiconductor element-holding surface. The surface of the semiconductor element is held by the semiconductor element-holding surface of the protrusion of the collet.

Abstract: The invention relates to a support (1) for rolling cylindrical elements, this support comprising first guide means (2) capable of guiding the cylindrical elements at a height z1. Downstream, in a direction in which the cylindrical elements roll, the said support (1) comprises second guide means capable of guiding the cylindrical elements at a height z2 higher than z1, the friction between the second guide means and the cylindrical elements being lower than the friction between the first guide means (2) and the cylindrical elements.

Abstract: A sheet finisher for executing preselected processing with a sheet introduced thereinto from an image forming apparatus and then discharging the sheet is disclosed. The sheet finisher includes a stacking device configured to temporarily stack sheets sequentially delivered thereto. Jogger fences jog each sheet within the stacking device. A stapler staples the sheet stack jogged in the stacking device. The stapler is supported by a guide shaft such it is movable along the guide shaft in a direction perpendicular to the direction of sheet conveyance and angularly movable in a direction perpendicular to the direction of guide.

Abstract: An image forming system enabling a cost reduction by decreasing the number of components and having enough performance levels of individual postprocessing functions, comprising: an image forming apparatus body and at least one postprocessing unit, the postprocessing unit selectable from a plurality of types of postprocessing units, wherein a single-sheet processing machine is provided as one of the plurality of types of postprocessing units and wherein the single-sheet processing machine has a plurality of types of single-sheet processing functions for postprocessing in units of a sheet and a sheet attachment function of attaching a cover sheet or an insert sheet to an output sheet bulk.

Abstract: A conveying apparatus for transporting sheets to a sheet processing machine, in particular a printing press, has a suction belt table between a sheet in-feed and the sheet-processing machine. A transport belt of the suction belt table is formed with at least two rows of suction openings that exert a holding force on the sheet. Ventilation openings that reduce a frictional force of the suction belt on the feed table are provided below the transport belt in a region between the rows of suction openings.

Abstract: A sheet treating apparatus to be connected to an image forming apparatus, which has a sheet guide portion which selectively guides a sheet to a sheet stacking portion or a sheet treating portion and, in a state in which a power supply of the sheet treating apparatus is turned off, the sheet guide portion guides a sheet to the sheet stacking portion such that a sheet delivered from the image forming apparatus can be stacked even if the power supply of the sheet treating apparatus is turned off. Moreover, a sheet can be stacked on the sheet stacking portion without using a transporting drive force of the sheet treating apparatus.

Abstract: The invention relates to a pile compartment for flat postal articles placed in an upright position, comprising a pile compartment bottom (7) and a pile compartment wall (6) perpendicular thereto. The postal articles (1) inside the pile compartment (5) rest against said pile compartment wall. The pile compartment also comprises a pile support (8), which holds the pile (11) and can be displaced along the pile compartment wall (6) in an approximately horizontal piling direction. At the end of the pile compartment (5), the pile support (8) can be lowered into the plane of the pile compartment bottom, and the pile compartment bottom (7) is provided, at least in part, with a profiled design. The pile support (8) is designed so that it meshes with the bottom profile via the pile support surface that, when raised, slides on the pile compartment bottom (7).

Abstract: In the sheet feeder, a first intermediate gear support shaft is inserted into a bearing of a first intermediate gear, and contains a bearing engaging part including a sectional shape having a substantial D-shaped cut having a flat part and a circular part. The bearing engaging part having a substantial D-shaped cut of the first intermediate gear support shaft contains two support parts and located on the boundary line between the flat part and the circular part. The support parts are arranged so as to support the circular bearing of the first intermediate gear at two positions sloping by a predetermined angle right and left for the line of a force which passes the center of the first intermediate gear and is applied to the first intermediate gear from the rotation. The support parts have a chamfered or rounded shape.

Abstract: A wagering game between a dealer and one or more players involving one or more decks of cards, a betting board and player markers. The betting board has four columns of betting places, each column corresponding to one of four card suits, said betting places being arranged in rows of four, one betting place for each column. Each row is set at a progressively increasing designated odds payoff. Each player makes a bet by selecting a betting place with a marker. A dealer deals one card to each player. If the column of the betting place matches the suit of the card dealt, the player is a winner. The winner may accept the designated odds payoff or may advance up the column to a higher designated odds payoff row. If the player's betting place column does not match the suit of the card dealt, the dealer is the winner. Players may make side bets on the value of the card dealt as agreed to between player and dealer.

Abstract: A system for determining the skill of a player eliminates the element of chance by comparing players who have the same initial position. In the case of cards, the initial position is the hand dealt to the player and in tile games, it is the initial distribution and arrangement of tiles. A player with a less than advantageous initial position may win a game over an opponent having a better initial position. It cannot conclusively be said whether this win is due to the good play of the winner or the bad play of the loser. However, it can clearly be said that the winning player has a higher skill level than the losing player.

Abstract: A mechanized ball-throwing game is provided, comprising at least one game play object, at least one rotating goal assembly, means to maintain a count of the number of times a game play object passes through each of the at least one rotating goal assembly in each of a plurality of designated directions, and means to display the count.

Abstract: A game in which a ball is thrown or bounced onto a horizontal game board from an adjacent bouncing surface such as a table, most of a target portion of the game board surface being covered with raised ball-deflecting projections in a grid pattern, the remainder of the target portion consisting of ball-retaining depressions defined by the projections and approximating the size of the ball. The ball is preferably a ping-pong type ball that reacts with the game board in a manner making it extremely difficult to place the ball in a particular scoring depression on the first bounce.

Abstract: A force-bearing object or non-penetrating projectile's contact location can be determined and mapped by a computer using methods of pressure, penetration, or stress sensitivity.

Abstract: A weapons qualification target having indicia thereon, including a photograph of a human being, a drawing of selected parts of the human anatomy, and a standard weapons qualification scoring pattern. The scoring pattern and the anatomical indicia are invisible from the usual firing distance for weapons qualification so that the shooter sees a realistic target when qualifying.

Abstract: A method of conducting a racing series for competitors and team owners is disclosed. The racing series has a plurality of races divided into a first and second set of races with competitors racing in both sets of races. The competitors and team owners are awarded points after each race, with those points being adjusted between the two sets of races. The points of only a predetermined number of competitors and/or team owners are adjusted between the sets of races. Awards, including a championship, is awarded based on the points accumulated during the racing series.

Abstract: An interactive game system for providing a spoons related game that promotes education of the United States. The interactive game system includes providing a card deck, a plurality of data cards, a plurality of playing spoons, and a data spoon. The data cards and the data spoon preferably include information regarding a subject such as the United States or a specific state. Based upon the number of players (N) present, N-1 data cards are inserted into the card deck and N-2 playing spoons along with the data spoon are placed in the center of the playing table. Each player is dealt five cards and the dealer then draws a card from the card deck. The dealer then may retain or pass the card to the player to their left. Play is continued until a player has four matching playing cards and a data card in their hand.

Abstract: A trivia game includes providing a plurality of balloons. A plurality of trivia cards is also provided. Each of the trivia cards has a different trivia question positioned thereon with respect to remaining ones of the trivia cards. Each of the balloons has one of the trivia cards positioned therein. Music is also provided. Each of the balloons is inflated and the music is played while the inflated balloons are hit between a plurality of competitors. A competitor catches the balloon or balloons when the music stops and then popped to retrieve the trivia card p positioned in the caught one of the balloons. The competitor retrieving the trivia card then attempts to answer the question on the trivia card and will receive a quantity of points for correctly answering the question.

Abstract: In a corner portion (2) defined between an outer peripheral surface (4) and a lower-side surface (3) of a steel piston ring (1), a groove (5, 6) having either an approximately quadrangular shape with a length of one side of 0.05 to 0.4 mm or an approximately quarter circular shape having a radius of 0.05 to 0.4 mm is formed. A sharp edge (9) formed by the groove (5, 6) performs an oil scraping function and the groove (5, 6) works to reduce an oil pressure of a second land or a third land clearance between the cylinder bore and the piston.