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WO1995001510A1 - A hydraulic, pneumatic or another similar cylinder - Google Patents

A hydraulic, pneumatic or another similar cylinder Download PDF

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Publication number
WO1995001510A1
WO1995001510A1 PCT/FI1993/000285 FI9300285W WO9501510A1 WO 1995001510 A1 WO1995001510 A1 WO 1995001510A1 FI 9300285 W FI9300285 W FI 9300285W WO 9501510 A1 WO9501510 A1 WO 9501510A1
Authority
WO
WIPO (PCT)
Prior art keywords
piston rod
cylinder
sensor
property variations
cylinder sleeve
Prior art date
Application number
PCT/FI1993/000285
Other languages
French (fr)
Inventor
Teijo Salmi
Sten Siren
Original Assignee
Partek Cargotec Oy
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Partek Cargotec Oy filed Critical Partek Cargotec Oy
Priority to DE4397478T priority Critical patent/DE4397478T1/en
Priority to AU45032/93A priority patent/AU4503293A/en
Priority to PCT/FI1993/000285 priority patent/WO1995001510A1/en
Publication of WO1995001510A1 publication Critical patent/WO1995001510A1/en

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/20—Other details, e.g. assembly with regulating devices
    • F15B15/28—Means for indicating the position, e.g. end of stroke
    • F15B15/2815—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT
    • F15B15/2846—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT using detection of markings, e.g. markings on the piston rod
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/347—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
    • G01D5/34746—Linear encoders
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
    • B41M5/262—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used recording or marking of inorganic surfaces or materials, e.g. glass, metal, or ceramics

Definitions

  • the present invention relates to a hydraulic, pneumatic or another similar cylinder, comprising a cylinder sleeve and a combination of a piston and a piston rod arranged to move axially in the cylinder sleeve and means for the determination of a position of the piston rod relative to the cylinder sleeve, which means consist of property variations provided on the piston rod concerning a capability of the sur ⁇ face of the piston rod of reflecting optical radia ⁇ tion and of a sensor for detecting these property variations, which sensor comprises at least one com ⁇ bination of a light source and a receiver.
  • a working cylinder as described above is known from German Offenlegungsschrift 3636730.
  • optically readable marks are made on the sur ⁇ face of the piston rod by coating the rod with an ⁇ other material, such as copper, the optical proper- ties of which differ sufficiently from the optical properties of the basic material of the rod, which in most cases is chrome.
  • these marks forming an in ⁇ crement scale, for instance, the position of the pis ⁇ ton rod can be followed by an optical sensor.
  • Such a known procedure for following the position of the piston rod has not become very general, however, the reason for which may be the great amount of work needed and the rather complicated equipment for pro ⁇ viding the marks as well as the high costs due to the above facts. Problems may have occurred also as far as the endurance of the marks is concerned.
  • the object of the present invention is thus to set forth a novel solution especially for making marks on a piston rod, which solution is considerably more advantageous than the prior art solution and has a better endurance and a better capability of giving information.
  • the above object has been achieved by means of a hydraulic, pneumatic or another similar cylinder according to the invention, which is characterized in that the property variations in the capability of the piston rod surface of reflecting optical radiation are provided by means of a laser beam.
  • a laser beam makes it possible that the optical property varia- tions forming an optically readable scale, which may contain absolute codes as well, if desired, are pro ⁇ vided economically and effectively.
  • a chromated surface is treated by means of a laser beam, coloured areas, in practice even black areas, are formed thereon. Thanks to its colours, the treated area has reflecting properties different from the reflecting properties of the surrounding area. Accordingly, such marks are easily readable by means of an optical de ⁇ vice. Since these marks, having a surface not pro- jecting substantially from the remaining surround ⁇ ings, are very wear-resistant, they do not wear even in long-term use to the extent so as to cause prob ⁇ lems of reading them by means of an optical device.
  • Figure 1 shows a cylinder according to the in ⁇ vention
  • Figure 2 shows a short portion of a piston rod of the cylinder of Figure 1
  • Figure 3 shows an exemplifying embodiment of a scale made on the piston rod of the cylinder accord ⁇ ing to the invention in greater detail
  • Figure 4 shows another embodiment of the scale made on the piston rod in greater detail
  • Figure 5 shows a block diagram of a sensor de ⁇ vice for reading the scale illustrated in Figure 3.
  • Figure 1 shows a cylinder 1 according to the invention, comprising a cylinder sleeve 2 and a com ⁇ bination 3 of a piston and a piston rod arranged to move axially therein.
  • Property variations 5 in the form of optically readable marks have been provided on the surface of this piston rod 3.
  • a reading device 6 is supported on the cylinder sleeve 2 for reading these marks made on the piston rod. The optical reading device is then positioned in a mecha ⁇ nically protected structure and it constitutes part of a sealing/bearing end piece of the cylinder. Both ends of the reading device 6 are provided with wipers (not shown) keeping the place to be read clean.
  • Figures 2 to 4 show exemplifying structure so ⁇ lutions for the scale to be provided on the surface of the piston rod 3 in more detail.
  • These scales which can naturally be formed entirely as desired, are realized by means of a laser beam in the way de ⁇ scribed above. Then the surface of the piston rod remains smooth, due to which it does not cause any extra wear on sealings or bearings. Moreover, a suf- ficient contrast can then be achieved between the metal surface and the marks so that the marks are readable by electro-optical readers. Marks provided by a laser beam are very hard and therefore endure the abrasive effect caused by the sealings and bear- ings very well.
  • the scale formed on the surface of the piston rod 3 can consist of a thread with a constant pitch all around the rod or of scale marks, as shown in Figures 2 to 4.
  • the piston rods can thus be manufac- tured as longer integral portions, which are then cut to finished piston rods.
  • the separative power of a sensor is determined by a line space of the scale and by the number of optical readers. An increment sensor is provided in this way. Finding out the absolute po- sition can be facilitated by placing absolute codes at fixed distances or on certain places on the rod. One such place is marked in Figure 3 in the form of a longer line. On the other hand, Figure 4 shows an ab ⁇ solute code 7, on the basis .
  • the number of the used scales and used readers depends in practice on the need of each object of use for an accurate position information in particular, because by changing the number or breadth of the lines and, on the other hand, by increasing the number of readers, the reading accuracy can be improved.
  • Reading of marks provided on the piston rod takes place optically by means of a reflection sensor either by visible light or infrared light at a cer- tain wavelength.
  • a reflection sensor either by visible light or infrared light at a cer- tain wavelength.
  • Several combinations of a light source and a receiver suitable for this purpose are known in this field. It is preferable to choose for the used light a wavelength at which the scale is best discernible.
  • Such a unity consisting of readers can be positioned, as shown in Figure 1, simply to form part of the end piece of the cylinder.
  • the read ⁇ ers can naturally be positioned, depending on the case in question, also in a separate support struc ⁇ ture outside the cylinder itself.
  • FIG. 5 shows a block diagram of a sensor structure for reading the scale illustrated in Figure 3.
  • This sensor comprises readers A, B and R, posi ⁇ tioned around the piston rod 3 in such a manner that their reading points are situated at points X, Y and Z of Figure 3. Pulse sequences similar to those of Figure 5 are then obtained from these readers.
  • the reader itself comprises a light source and a light receiver receiving the light reflected from the scale of the piston rod.
  • the signals changed into electric signals by the receivers are digitized in blocks 8, whereby pulse sequences similar to those shown in Figure 5 are obtained.
  • a certain absolute position on the piston rod is firstly found out by means of the pulse se ⁇ quence R and, on the other hand, the number of pulses, i.e. the distance from the position of the absolute mark, and the direction of motion of the piston rod are found out by means of the pulses A and B.
  • the pulse length of the pulses A and B corresponds to the time during which the mark passes the reader, it is possible to determine the speed of motion of the piston rod on the basis of the length of these pulses.
  • a from-edge-to-edge sensor 9 for the pulses A and B is provided for this measure, which sensor de ⁇ termines the length of the pulse, and a pulse length voltage transducer 10 is provided for transducing this pulse length to a voltage value.
  • a voltage which can be for instance in the area 0 to 5 V and which is di ⁇ rectly proportional to the speed of the piston rod.
  • Figure 4 shows an exemplifying alternative to the scale illustrated in Figure 3, in which an abso- lute code (for instance figure 20) is provided by means of the marks 7, by means of which code the reader can read the absolute position of the piston rod directly as a numerical code.
  • abso- lute code for instance figure 20
  • the cylinder of the invention has been described by means of one exemplifying embodiment only and it is understandable that numerous altera ⁇ tions can be made therein without differing from the scope of protection defined by the attached claims, however. Accordingly, as mentioned above, the shapes of the scales can vary even very arbitrarily.
  • the most significant advantage of the cylinder according to the invention is that the scale marks are very hard and wear-resistant even in the simplest imple ⁇ mentation, but do not, however, cause any changes in the surface of the piston rod, as far as its use ex ⁇ pressly as a piston rod is concerned.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Abstract

The present invention relates to a hydraulic, pneumatic or another similar cylinder (1), comprising a cylinder sleeve (2) and a combination (3) of a piston and a piston rod arranged to move axially in the cylinder sleeve and means (4) for the determination of a position of the piston rod relative to the cylinder sleeve (2), which means consist of property variations (5) provided on the piston rod concerning a capability of the surface of the piston rod (3) of reflecting optical radiation and of a sensor (6) for detecting these property variations, which sensor (6) comprises at least one combination of a light source and a receiver. The property variations (5) on the piston rod have been provided according to the invention by means of a laser beam both efficiently and advantageously.

Description

A hydraulic, pneumatic or another similar cylinder
The present invention relates to a hydraulic, pneumatic or another similar cylinder, comprising a cylinder sleeve and a combination of a piston and a piston rod arranged to move axially in the cylinder sleeve and means for the determination of a position of the piston rod relative to the cylinder sleeve, which means consist of property variations provided on the piston rod concerning a capability of the sur¬ face of the piston rod of reflecting optical radia¬ tion and of a sensor for detecting these property variations, which sensor comprises at least one com¬ bination of a light source and a receiver. A working cylinder as described above is known from German Offenlegungsschrift 3636730. According to that, optically readable marks are made on the sur¬ face of the piston rod by coating the rod with an¬ other material, such as copper, the optical proper- ties of which differ sufficiently from the optical properties of the basic material of the rod, which in most cases is chrome. With these marks forming an in¬ crement scale, for instance, the position of the pis¬ ton rod can be followed by an optical sensor. Such a known procedure for following the position of the piston rod has not become very general, however, the reason for which may be the great amount of work needed and the rather complicated equipment for pro¬ viding the marks as well as the high costs due to the above facts. Problems may have occurred also as far as the endurance of the marks is concerned.
The object of the present invention is thus to set forth a novel solution especially for making marks on a piston rod, which solution is considerably more advantageous than the prior art solution and has a better endurance and a better capability of giving information.
The above object has been achieved by means of a hydraulic, pneumatic or another similar cylinder according to the invention, which is characterized in that the property variations in the capability of the piston rod surface of reflecting optical radiation are provided by means of a laser beam. A laser beam makes it possible that the optical property varia- tions forming an optically readable scale, which may contain absolute codes as well, if desired, are pro¬ vided economically and effectively. When a chromated surface is treated by means of a laser beam, coloured areas, in practice even black areas, are formed thereon. Thanks to its colours, the treated area has reflecting properties different from the reflecting properties of the surrounding area. Accordingly, such marks are easily readable by means of an optical de¬ vice. Since these marks, having a surface not pro- jecting substantially from the remaining surround¬ ings, are very wear-resistant, they do not wear even in long-term use to the extent so as to cause prob¬ lems of reading them by means of an optical device.
In the following a cylinder according to the invention and optional structures thereof are de¬ scribed in more detail referring to the attached drawing, in which
Figure 1 shows a cylinder according to the in¬ vention, Figure 2 shows a short portion of a piston rod of the cylinder of Figure 1,
Figure 3 shows an exemplifying embodiment of a scale made on the piston rod of the cylinder accord¬ ing to the invention in greater detail, Figure 4 shows another embodiment of the scale made on the piston rod in greater detail and
Figure 5 shows a block diagram of a sensor de¬ vice for reading the scale illustrated in Figure 3.
Figure 1 shows a cylinder 1 according to the invention, comprising a cylinder sleeve 2 and a com¬ bination 3 of a piston and a piston rod arranged to move axially therein. Property variations 5 in the form of optically readable marks have been provided on the surface of this piston rod 3. Additionally, a reading device 6 is supported on the cylinder sleeve 2 for reading these marks made on the piston rod. The optical reading device is then positioned in a mecha¬ nically protected structure and it constitutes part of a sealing/bearing end piece of the cylinder. Both ends of the reading device 6 are provided with wipers (not shown) keeping the place to be read clean.
Figures 2 to 4 show exemplifying structure so¬ lutions for the scale to be provided on the surface of the piston rod 3 in more detail. These scales, which can naturally be formed entirely as desired, are realized by means of a laser beam in the way de¬ scribed above. Then the surface of the piston rod remains smooth, due to which it does not cause any extra wear on sealings or bearings. Moreover, a suf- ficient contrast can then be achieved between the metal surface and the marks so that the marks are readable by electro-optical readers. Marks provided by a laser beam are very hard and therefore endure the abrasive effect caused by the sealings and bear- ings very well.
The scale formed on the surface of the piston rod 3 can consist of a thread with a constant pitch all around the rod or of scale marks, as shown in Figures 2 to 4. The piston rods can thus be manufac- tured as longer integral portions, which are then cut to finished piston rods. The separative power of a sensor is determined by a line space of the scale and by the number of optical readers. An increment sensor is provided in this way. Finding out the absolute po- sition can be facilitated by placing absolute codes at fixed distances or on certain places on the rod. One such place is marked in Figure 3 in the form of a longer line. On the other hand, Figure 4 shows an ab¬ solute code 7, on the basis . of which the position of the piston rod can be found out also when it is for some reason not possible to count the number of pulses starting from some extreme position, for in¬ stance, or from a place mark as shown in Figure 3 or if such an information has been lost in the meantime for some reason. The number of the used scales and used readers depends in practice on the need of each object of use for an accurate position information in particular, because by changing the number or breadth of the lines and, on the other hand, by increasing the number of readers, the reading accuracy can be improved.
Reading of marks provided on the piston rod takes place optically by means of a reflection sensor either by visible light or infrared light at a cer- tain wavelength. Several combinations of a light source and a receiver suitable for this purpose are known in this field. It is preferable to choose for the used light a wavelength at which the scale is best discernible. Such a unity consisting of readers can be positioned, as shown in Figure 1, simply to form part of the end piece of the cylinder. The read¬ ers can naturally be positioned, depending on the case in question, also in a separate support struc¬ ture outside the cylinder itself. Then the wipers of the piston rod cannot be positioned in connection with the very readers, because they shall always be in mechanical contact with the piston rod itself so that the piston rod can be cleaned in a desired area to make the reading possible. Figure 5 shows a block diagram of a sensor structure for reading the scale illustrated in Figure 3. This sensor comprises readers A, B and R, posi¬ tioned around the piston rod 3 in such a manner that their reading points are situated at points X, Y and Z of Figure 3. Pulse sequences similar to those of Figure 5 are then obtained from these readers. The reader itself comprises a light source and a light receiver receiving the light reflected from the scale of the piston rod. After this the signals changed into electric signals by the receivers are digitized in blocks 8, whereby pulse sequences similar to those shown in Figure 5 are obtained. By comparing the pulse sequences given by the readers A, B and R with each other, a certain absolute position on the piston rod is firstly found out by means of the pulse se¬ quence R and, on the other hand, the number of pulses, i.e. the distance from the position of the absolute mark, and the direction of motion of the piston rod are found out by means of the pulses A and B. Besides, because the pulse length of the pulses A and B corresponds to the time during which the mark passes the reader, it is possible to determine the speed of motion of the piston rod on the basis of the length of these pulses. In the block diagram of Fig- ure 5, a from-edge-to-edge sensor 9 for the pulses A and B is provided for this measure, which sensor de¬ termines the length of the pulse, and a pulse length voltage transducer 10 is provided for transducing this pulse length to a voltage value. As an output of the transducer 10 is obtained a voltage, which can be for instance in the area 0 to 5 V and which is di¬ rectly proportional to the speed of the piston rod.
Figure 4 shows an exemplifying alternative to the scale illustrated in Figure 3, in which an abso- lute code (for instance figure 20) is provided by means of the marks 7, by means of which code the reader can read the absolute position of the piston rod directly as a numerical code.
Above the cylinder of the invention has been described by means of one exemplifying embodiment only and it is understandable that numerous altera¬ tions can be made therein without differing from the scope of protection defined by the attached claims, however. Accordingly, as mentioned above, the shapes of the scales can vary even very arbitrarily. The most significant advantage of the cylinder according to the invention is that the scale marks are very hard and wear-resistant even in the simplest imple¬ mentation, but do not, however, cause any changes in the surface of the piston rod, as far as its use ex¬ pressly as a piston rod is concerned.

Claims

Claims :
1. A hydraulic, pneumatic or another similar cylinder (1), comprising a cylinder sleeve (2) and a combination (3) of a piston and a piston rod arranged to move axially in the cylinder sleeve and means (4) for the determination of a position of the piston rod relative to the cylinder sleeve (2), which means con¬ sist of property variations (5) provided on the pis- ton rod concerning a capability of the surface of the piston rod (3) of reflecting optical radiation and of a sensor (6) for detecting these property variations, which sensor (6) comprises at least one combination of a light source and a receiver, c h a r a c - t e r i z e d in that the property variations (5) in the capability of the piston rod (3) surface of re¬ flecting optical radiation are provided by means of a laser beam.
2. A cylinder according to claim 1, c h a r - a c t e r i z e d in that the property variations
(5) provide an optically readable scale on the sur¬ face of the piston rod.
3. A cylinder according to claim 2, c h a r¬ a c t e r i z e d in that the scale comprises abso- lute codes (7).
PCT/FI1993/000285 1993-07-02 1993-07-02 A hydraulic, pneumatic or another similar cylinder WO1995001510A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE4397478T DE4397478T1 (en) 1993-07-02 1993-07-02 Hydraulic, pneumatic or similar cylinder
AU45032/93A AU4503293A (en) 1993-07-02 1993-07-02 A hydraulic, pneumatic or another similar cylinder
PCT/FI1993/000285 WO1995001510A1 (en) 1993-07-02 1993-07-02 A hydraulic, pneumatic or another similar cylinder

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/FI1993/000285 WO1995001510A1 (en) 1993-07-02 1993-07-02 A hydraulic, pneumatic or another similar cylinder

Publications (1)

Publication Number Publication Date
WO1995001510A1 true WO1995001510A1 (en) 1995-01-12

Family

ID=8556557

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1993/000285 WO1995001510A1 (en) 1993-07-02 1993-07-02 A hydraulic, pneumatic or another similar cylinder

Country Status (3)

Country Link
AU (1) AU4503293A (en)
DE (1) DE4397478T1 (en)
WO (1) WO1995001510A1 (en)

Cited By (23)

* Cited by examiner, † Cited by third party
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FR2746457A1 (en) * 1996-03-22 1997-09-26 Valeo Hydraulic slave cylinder for operating clutch thrust bearing for motor vehicles
EP0947805A3 (en) * 1998-04-02 1999-12-01 J.C. Bamford Excavators Limited An apparatus for determining the position of a movable mechanical element and method of marking a mechanical element
WO2000059767A1 (en) * 1999-04-01 2000-10-12 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Steering device for vehicles
US6147342A (en) * 1998-06-02 2000-11-14 Caterpillar Inc. Encoding system for determining the position of a cylinder rod along a path of movement
WO2001014750A3 (en) * 1999-08-20 2001-09-13 Samson Ag Control-valve drive with sensor unit for detecting the position of the valve
DE10119941A1 (en) * 2001-04-23 2002-10-24 Mannesmann Rexroth Ag Relative position measurement for piston rod in a pressure medium cylinder, uses random coding, e.g. Manchester coding, of the coding elements along the length of the piston rod
US6556946B2 (en) 2000-12-19 2003-04-29 Caterpillar Inc Linear position sensor
EP1398602A2 (en) * 2002-09-13 2004-03-17 MAHA Maschinenbau Haldenwang GmbH & Co. KG Device for measuring and controlling the position of a lifting platform
US6941827B2 (en) 2003-12-19 2005-09-13 Caterpillar Inc. Mounting apparatus and method for cylinder position sensor
WO2005085765A1 (en) * 2004-03-03 2005-09-15 BSH Bosch und Siemens Hausgeräte GmbH Reversing linear drive comprising means for detecting an armature position
US7178446B2 (en) 2005-02-28 2007-02-20 Caterpillar Inc Cylinder rod with position sensor surface markings
RU2301914C1 (en) * 2005-10-11 2007-06-27 ООО "Фесто-РФ" Hydraulic or pneumatic cylinder (versions) and device for checking position of piston in hydraulic or pneumatic cylinder
WO2009053812A3 (en) * 2007-10-22 2009-07-02 A M A S P A System for determining the position of a piston along its path of travel for a fluid-dynamic actuator
CN102865267A (en) * 2012-09-05 2013-01-09 江苏讯为电子器材有限公司 Marked stroke-adjustable air cylinder
CN104806601A (en) * 2015-04-22 2015-07-29 中意凯盛（蚌埠）玻璃冷端机械有限公司 Stroke regulating device with double-piston-rod air cylinder
CN105221524A (en) * 2014-06-27 2016-01-06 罗伯特·博世有限公司 Method for producing a component with a distance measuring system
CN105473873A (en) * 2013-08-07 2016-04-06 光电意大利有限公司 Cylinder-piston unit and method of detecting continuosly the reciprocal position between cylinder and piston of such unit
EP3214410A1 (en) 2016-03-02 2017-09-06 Jungheinrich Aktiengesellschaft Cylinder with an optical position sensor
EP3299637A1 (en) * 2016-09-21 2018-03-28 Jungheinrich Aktiengesellschaft Fluid cylinder with an optical sensor unit
DE102017118509A1 (en) 2017-08-14 2019-02-14 Jungheinrich Aktiengesellschaft Cylinder with a piston rod and an optical position gauge
CN110926320A (en) * 2019-11-20 2020-03-27 常州武宏机械科技有限公司 Measuring and positioning device and method based on one-dimensional code
EP3693708A1 (en) 2019-02-08 2020-08-12 Jungheinrich Aktiengesellschaft Cylinder with a piston rod and an optical position sensor
CN112145399A (en) * 2019-06-28 2020-12-29 青岛海尔智能技术研发有限公司 Compressors and refrigeration equipment

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US4756229A (en) * 1986-09-25 1988-07-12 United Technologies Corporation Digital motor feedback for a position actuator
EP0296808A1 (en) * 1987-06-22 1988-12-28 Parker Hannifin Corporation Monitoring system for position sensing and reciprocating rod used therein

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US4756229A (en) * 1986-09-25 1988-07-12 United Technologies Corporation Digital motor feedback for a position actuator
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EP0296808A1 (en) * 1987-06-22 1988-12-28 Parker Hannifin Corporation Monitoring system for position sensing and reciprocating rod used therein

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Cited By (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2746457A1 (en) * 1996-03-22 1997-09-26 Valeo Hydraulic slave cylinder for operating clutch thrust bearing for motor vehicles
EP0947805A3 (en) * 1998-04-02 1999-12-01 J.C. Bamford Excavators Limited An apparatus for determining the position of a movable mechanical element and method of marking a mechanical element
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EP1426737A3 (en) * 1998-04-02 2004-12-15 J.C. Bamford Excavators Limited An apparatus for determining the position of a moveable mechanical element and method of marking a mechanical element
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