A cylinder-piston unit including: at least one cylinder including a tubular body (2); at least one piston (5) liable with a respective rod (5a), said piston (5) and said rod (5a) being translatable longitudinally in said tubular body (2) of said cylinder, at least one reference codification (C) extending for at least a section (dC) on the surface of said rod (5a), along the longitudinal axis of the same; at least detecting means (7), movable anchorable to said tubular body (2), faced, in use, towards said rod (5a) and suitable to detect said at least one reference codification (C) and to emit at the output at least a corresponding output electrical signal (s7), at least a reference zone (7c) of amplitude (d7c) delimited from said detecting means (7), said at least one reference codification (C) being detectable in correspondence to said at least one detection zone (7c); said at least one reference codification (C) including at least one plurality of adjacent sectors ( . . . , Si1, Si, Si+1, . . . ) extending along said longitudinal axis of said rod (5a), each of them for a section (dSi) of equal length; each sector (Si) includes a plurality of optical contrast zones (si1, si2, si3), each of them extending along said longitudinal axis of said rod (5a) for a respective section of extension (dsi1, dsi2, dsi3) such as the sum of the extensions of said sections of extensions (dsi1+dsi2 . . . ), in each sector (Si) is lower or equal to said amplitude (d7c) of said detecting zone (7c); said optical contrast zones (si1, si2, si3) being arranged in each sector (Si) according to the same sequence; and wherein in each sector (Si) at least one optical contrast zone (si1, si2, si3) shows said at least one respective section of extension (ds1, ds2, ds3) of different length compared to the length of the same section of extension in the other sectors (Si2, Si1, Si+1, Si+2, . . . ), therefore each sector (Si) remains univocally definable from the length of said at least one section of extension (dsi1, dsi2, dsi3) of said optical contrast zones (si1, si2, si3) in it included.

The present invention relates to using a self calibrating and recalibrating 230, 925 optical sensors piston rod displacement. Self calibration enables field calibration of uncalibrated 230, 925 optical sensors. During operation, recalibration enables detecting and correcting for wear and damage of the 200 piston rod and/or 230, 925 optical sensors. 210 Calibration positions on the surface of the 200 piston rod are imaged by 230 optical sensors using laser or darkfield lenses designed for optical computer mice. Natural surface patterns can be used in locations where 210 calibration positions are required, which reduces or eliminates the need for marked 210 calibration positions. Marked 210 calibration positions are spatially unique encoded sequences used to determine the piston rod absolute position. Storing only the significant features of 210 calibration positions saves significant memory. The reduced memory requirements of each 210 calibration position enables the use of closely spaced or continuous 210 calibration positions. Multiple 210 calibration position features and multiple 230, 925 optical sensors together collectively provide immunity to localized 208 surface damage. Proximity sensors, 925 time of flight sensors and 031 cumulative relative displacement are used to estimate the 200 piston rod absolute displacement and reduce the number of spatially unique 210 calibration positions needed to compare in order to determine the piston rod absolute displacement.

A pressure vessel arrangement includes a pressure vessel and an optical sensor arrangement. The pressure vessel includes: a cylinder construction having a cylinder wall extending from a cylinder wall first end to a cylinder wall second end, and having an internal surface forming an interior region; a first end cap closing the cylinder wall first end and having an optical window located therein to permit passage of light therethough and into the interior region; a second end cap closing the cylinder wall second end; and a piston constructed to slide within the cylinder construction interior region along a direction between the cylinder all first end and the cylinder wall second end and along the cylinder construction internal surface to separate the interior region into a first end interior region and a second end interior region. The pressure vessel is constructed to withstand a fatigue test of one million cycles at 5,000 psi without failure. The optical sensor arrangement is located outside of the optical window and includes an emitter for emitting light through the optical window and into the interior region and receiving for receiving light reflected from the piston. Also included is a method for providing a piston position feedback in a pressure vessel.

A sensor (S) is provided for determining the stroke of the piston rod (6) of a fluid cylinder, particularly a hydraulic or pneumatic cylinder. The sensor includes a lighting unit for illuminating a code applied on the surface of the piston rod and differing from said surface by color, a first camera unit with a first lens system for recording a first image of the illuminated code in a first scanning window, an evaluation unit for evaluating output signals of the first camera unit, and an interface for issuing the evaluated output signals as information regarding the position of the piston rod. Additionally, a second redundant camera unit is provided with a second lens system, which serves for recording a second image of the illuminated code in a second scanning window. According to the invention the second camera unit is arranged such that the second scanning window is spaced apart in the direction of the extension of the piston rod by a predetermined value from the first scanning window of the first camera unit. The output signals of the second camera unit are evaluated in an evaluation unit as information about the respective position by forming a difference, with in case of said difference being consistent with a predetermined value the output signal being considered information about the stroke of the piston rod, and in case of inconsistency of the difference with the predetermined value an error message being issued.

A system for determining the stroke of a hydraulic cylinder is provided. The hydraulic cylinder includes a barrel with a rod that slidably extends therefrom. A fiber optic shape sensing system is positioned to determine the stroke of the rod relative to the barrel. An interrogation module is fixed to a reference frame. A fiber bundle is joined to the interrogation module at a proximal end and a fiber termination at a distal end, which is joined to the connecting end of the rod. A signal conditioning module connected to the interrogation module is configured to compute the location of at least one position of the fiber bundle relative to the reference frame; and provide an output indicative of the stroke of the connecting end relative to the barrel.

Disclosed are a method and a device for detecting a position of a piston rod, a hydraulic cylinder and a working machine. The method includes: acquiring a target image at a target position; obtaining a pixel information corresponding to the target image; comparing the pixel information with a pixel database of the piston rod, a full-stroke pixel information of the piston rod and a relationship between the full-stroke pixel information of the piston rod and a displacement of the piston rod are stored in the pixel database of the piston rod, and the full-stroke pixel information at least comprises the pixel information within a range in which the piston rod is configured to move relative to the target position; and determining a position information of the piston rod based on a comparison result.

The invention relates to a piston-cylinder unit. A piston motion sensor is arranged in a transverse bore of a cylinder head of the piston-cylinder unit. According to the invention, a positioning and/or alignment element is supported in the transverse bore on a floor, on which in turn the piston motion sensor is supported. The positioning and/or alignment element predetermines the axial position of the piston motion sensor in the transverse bore. In addition, the positioning and/or alignment element can predetermine the alignment of the piston motion sensor.

The piston-cylinder unit can be used, for example, for a work machine, construction machine, agricultural machine, a maritime machine, a wheeled loader, a digger, a dump truck, a crane, a forklift or a lifting platform.

The invention relates to a piston-cylinder unit. A piston motion sensor is arranged in a transverse bore of a cylinder head of the piston-cylinder unit. According to the invention, the transverse bore is separated from a pressure chamber which pressurises a piston of the piston-cylinder unit. This separation can be achieved by a collimator arranged in the beam path of a sensor signal being sealed off from a sensor signal channel by means of a sealing element. The seal can be used to enable the housing of the piston movement sensor to be detached from the transverse bore without the fluid escaping from the pressure chamber into the environment.

The piston-cylinder unit can be used, for example, for a working machine, construction machine, agricultural machine, maritime machine, wheel loader, digger, dump truck, crane, forklift or lifting platform.

The invention discloses a telescopic seatpost system comprising means to lock the position of the seat (S) in predefined positions in response to the pulsation of a button by the cyclist, without the need for the cyclist to keep said button (41) pushed during the time the telescopic mechanism (2) supporting the seat (S) is compressing or extending.

The invention relates to a piston-cylinder unit. A piston motion sensor is arranged in a transverse bore of a cylinder head of the piston-cylinder unit. According to the invention, a positioning and/or alignment element is supported in the transverse bore on a floor, on which in turn the piston motion sensor is supported. The positioning and/or alignment element predetermines the axial position of the piston motion sensor in the transverse bore. In addition, the positioning and/or alignment element can predetermine the alignment of the piston motion sensor. The piston-cylinder unit can be used, for example, for a work machine, construction machine, agricultural machine, a maritime machine, a wheeled loader, a digger, a dump truck, a crane, a forklift or a lifting platform.