EP0591614A1 - Actuator - Google Patents

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Publication number
EP0591614A1
EP0591614A1 EP93107873A EP93107873A EP0591614A1 EP 0591614 A1 EP0591614 A1 EP 0591614A1 EP 93107873 A EP93107873 A EP 93107873A EP 93107873 A EP93107873 A EP 93107873A EP 0591614 A1 EP0591614 A1 EP 0591614A1
Authority
EP
European Patent Office
Prior art keywords
piston
piston rod
cylinder
markings
unit according
Prior art date
Legal status (The legal status 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 status listed.)
Granted
Application number
EP93107873A
Other languages
German (de)
French (fr)
Other versions
EP0591614B1 (en
Inventor
Kurt Dipl.-Ing. Stoll
Lothar Müller
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Festo SE and Co KG
Original Assignee
Festo SE and Co KG
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 Festo SE and Co KG filed Critical Festo SE and Co KG
Publication of EP0591614A1 publication Critical patent/EP0591614A1/en
Application granted granted Critical
Publication of EP0591614B1 publication Critical patent/EP0591614B1/en
Anticipated expiration legal-status Critical
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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
    • F15B15/2807—Position switches, i.e. means for sensing of discrete positions only, e.g. limit switches
    • 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
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/1414—Characterised by the construction of the motor unit of the straight-cylinder type with non-rotatable piston
    • 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
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/1414—Characterised by the construction of the motor unit of the straight-cylinder type with non-rotatable piston
    • F15B15/1419—Characterised by the construction of the motor unit of the straight-cylinder type with non-rotatable piston of non-circular cross-section
    • 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
    • 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
    • F15B15/2853—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT using potentiometers

Definitions

  • the invention relates to a piston-cylinder unit, with a piston rod protruding from the cylinder on at least one end face, and with means for determining the position of the piston rod and / or the piston connected to it and arranged in the cylinder.
  • the most common measure to determine the position of the piston and / or the piston rod in piston-cylinder units is to arrange a permanent magnet on the piston, which can actuate a sensor fixed on the outside of the circumference of the cylinder without contact due to its magnetic field.
  • the attachment of the permanent magnet to the piston is, however, relatively complex and often requires special sealing measures.
  • the sensor arranged on the outside of the cylinder causes an increase in the overall width of the cylinder and impairs its fastening options.
  • the piston rod has on the circumference at least one supporting surface which extends over a large part of its length and has a flat shape and on which a measuring section which extends in the longitudinal direction of the piston rod and is optically or electrically interrogable is fixedly arranged.
  • An at least partially flattened piston rod is therefore used as a carrier for a suitable measuring section.
  • a precise interrogation or reading of the measuring section is possible.
  • an anti-rotation lock is achieved so that the measuring section always assumes the same angular position with respect to the cylinder. Since the measuring section is simply attached to the piston rod from the outside, the prerequisites for economical manufacture are met.
  • a square rod as the piston rod, one or more wings being formed by a corresponding number of the four rod surfaces arranged on the circumference. If necessary, you can have several measuring sections Attach to the piston rod offset in the circumferential direction. If the square bar is rectangular in cross-section and in particular square, the manufacture is particularly simple and, at the same time, optimum support is obtained in the penetration area of the associated cylinder cover. The bar edges can be rounded.
  • a measuring section which is particularly simple in terms of production technology and can also be queried in an uncomplicated manner is composed of a plurality of markings which follow one another in the longitudinal direction of the piston rod and which can be designed in the manner of scale marks.
  • a direct visual reading by an observer is possible as well as the use of an optical sensor, which is able to register the advancing markings and which is fixed in particular on the cylinder cover penetrated by the piston rod.
  • the markings or scale lines can in particular have been mechanically incised and / or etched into the wing and / or introduced by laser radiation. These are extremely fine surface depressions that do not cause any leaks or wear of existing sealing devices in the penetration area of the assigned cylinder cover.
  • a resistance strip can also be provided as the measuring section be, which extends along the wing and either placed on this and it is embedded in. It is acted upon by a sliding contact arranged fixed to the cylinder, so that an electrical change in resistance due to the displacement of the resistance strip can be registered and allows conclusions to be drawn about the current piston rod position.
  • the exemplary embodiments of both figures include a cylinder 1 in which a piston 2 (not shown in more detail in FIG. 1) is accommodated in an axially displaceable manner.
  • a piston rod 3 On the piston 2 is a piston rod 3, which extends in the longitudinal direction of the cylinder and penetrates a cylinder cover 4, which closes one end of the cylinder 1. In principle, it can be a continuous piston rod which then also penetrates the second cylinder cover 5 (not shown).
  • connection openings 8 open, which in a manner known per se allow the supply and / or discharge of pressure medium in order to move the piston 2 together with the piston rod 3 back and forth in the axial direction 12.
  • This is a pneumatic unit that is operated with compressed air.
  • Both piston-cylinder units shown in the figures are therefore equipped with means 13 for determining the position of the piston rod.
  • a measuring section 14 which can be detected optically or electrically. It extends in the longitudinal direction 12 of the piston rod 3 and is fastened to a support surface 15 formed on the piston rod 3.
  • the wing 15 thus practically forms a support for the measuring section 14 and extends along the piston rod 3 over at least a large part of its length. It is characterized in that it has a flat shape and is therefore not, as is usual with piston rods, provided with a rounded contour.
  • the supporting surface 15 extends over the entire length of the piston rod 3 as far as the piston 2, for example.
  • the measuring section 14 can also extend over this entire length, but is somewhat shorter in the exemplary embodiment, so that it ends at a short distance in front of both the fastening device 16 and the piston 2. In any case, it should expediently be so long that it extends at least approximately over the entire length of the piston rod section located outside the cylinder cover 4 when the piston rod 3 is fully extended.
  • the piston rod 3 is expediently designed as a polygonal rod, which in the case of the exemplary embodiments is a square rod which has a square cross section.
  • the wing 15 is formed by one of the four outer flat rod surfaces.
  • the measuring section 14 is composed of a plurality of markings 18 which follow one another in the longitudinal direction 12 of the piston rod 3 at a distance. These are preferably line-like markings 18, which each run transversely to the longitudinal direction 12 of the piston rod 3, so that the measuring section 14 represents a type of scale. This can easily be read visually by an observer during operation in order to find out the current relative position between the piston rod 3 and the cylinder 1. It is expedient if there is a cylinder-fixed reference edge 19 on which the markings 18 are moved past and which enables an exact reproducible reading. In the exemplary embodiment according to FIG. 1, such a reference edge 19 is formed directly by a body edge of the cylinder cover 4, specifically where the opening 17 opens out axially. The reference edge 19 is thus the end edge of the cylinder cover 4 in the passage area of the piston rod 3.
  • an optical sensor 22 indicated by dash-dotted lines in FIG. 1, which is expediently located outside the cylinder 1.
  • it sits on the end face of the cylinder cover 4 assigned to the piston rod 3. It protrudes over the wing 15 and is designed such that it can read and / or count the markings 18 that have passed.
  • Each marker 18 that is moved past triggers an electrical pulse that arrives at an evaluation unit 24 via a signal line 23.
  • the signals are evaluated there so that, for example, an optical display of the current position and the distance covered is possible. It goes without saying that the signals obtained can be used as desired.
  • a particularly simple and low-wear construction results if the markings 18 are incised in the piston rod 3. This can be done using suitable sharp-edged tools. However, it is also possible to introduce these markings into the wing 15 by etching or by means of laser beams. In front All of the latter two measures ensure that the depth of marking is very small. Optimal readability is thereby achieved while avoiding sealing problems in the penetration area 17 of the cylinder cover 4. The depths of the mark are so small that a sealing device arranged there is not damaged. Leaks are excluded, since the depressions run transversely, so that there is no connection between the surroundings and the cylinder space 7 adjoining on the inside.
  • the measuring section 14 is in the form of an electrical resistance strip 25.
  • This is glued to the piston rod 3, for example, which has been found to be the best of the possible fixed connection types.
  • the resistance strip 25 can be raised on the wing 15.
  • the seal in the penetration area of the cylinder cover 4 can, however, be handled much better if, as can be seen in FIG. 2, it comes to lie sunk in the wing 15.
  • the wing 15 has a longitudinal groove 26 of suitable depth, in which the resistance strip 25 is inserted.
  • the outward-facing surface of the resistance strip 25 forms a sliding surface 27, which preferably merges flush with the adjacent surface regions of the supporting surface 15.
  • the resistance strip 25 is opposite in the exemplary embodiment the piston rod 3 is electrically insulated, which in the present case consists of an electrically conductive material such as aluminum material or steel.
  • the insulation is carried out, for example, by interposing a stored insulation layer 30. Only with one of its two axial end regions, in the present case the end region 28 lying outside the cylinder 1, is the resistance strip 25 in an electrically conductive connection with the piston rod 3.
  • the connection point is indicated at 29.
  • a first sliding contact 32 is provided, which is fastened in an insulated manner to the cylinder 1 and, in particular, is seated on an axial projection 39 of the cylinder cover 4 that surrounds the piston rod 3.
  • the sliding contact 32 is on the one hand under resilient prestress in contact with the sliding surface 27. On the other hand, it is connected via an electrical line 33 to an evaluation unit 34.
  • a second sliding contact 35 is also mounted on the cylinder cover 4 in an electrically insulated manner and is in spring-loaded prestress in contact with a section of the piston rod 3 located next to the resistance strip 25 is not used as wings. It makes sense to use the rod surface 36 diametrically opposite the support surface 15 as the contact surface for the second sliding contact 35.
  • the second sliding contact 35 is also connected to the evaluation unit 34 via an electrical line 33 '.
  • the electrical resistance of the resistance strip 25 is chosen so that that of the piston rod 3 and also the contact resistance to the sliding contacts 32, 35 are negligible. Now a voltage is applied to the two electrical lines 33, 33 ', which generates a current flow. The current flows from the electrical line 33 'to the second sliding contact 35, from there to the piston rod 3 and in this to the connecting point 29, further along the resistance strip 25 to the contact point 37 of the first sliding contact 32, and then via this first sliding contact 32 and the electrical line 33 back to the evaluation unit 32, where the voltage source is located.
  • the relevant electrical resistance, which is generated by the resistance strip 25, is decisive for the current strength. This is determined by the axial length of the strip section 38 currently lying between the connection point 29 and the contact point 37 of the first sliding contact 32.
  • the strip section 38 is longer the further the piston rod 3 is extended, and accordingly the electrical resistance increases, which can be registered in the evaluation unit 35 as a current change.
  • the two sliding contacts 32, 35 grind along the sliding surface 27 and along the rod surface 36.
  • the evaluation unit 34 is able to determine the current position and / or the distance traveled by the piston rod 3 in relation to the cylinder 1 also display. Depending on certain values, further switching functions can then also be triggered.
  • the described potentiometer measuring principle would also work if the connection point 29 is moved to the axially inner end of the resistance strip 25.
  • the sliding contacts 32, 35 used according to the example are resilient metal sheets which, starting from the cylinder cover 4, run obliquely outwards axially and at the same time in the direction of the piston rod 3. It would also be conceivable to use sliding contacts which are pressed exactly radially against the piston rod 3 or the resistance strip 25 and in particular are under the pretension of a spring arrangement. It would be possible to integrate these sliding contacts in the axial projection 39 provided according to the example and coaxially surrounding the piston rod 3 on the outside of the cylinder cover 4.
  • the piston rod 3 would be provided with an axially extending cavity 40 which is open towards the cylinder cover 5.
  • a contact rod 41 which is attached to this cylinder cover 4 in a particularly insulated manner, then projects axially into the cavity 40 and carries a sliding contact 35 ′, which is in an electrically conductive sliding connection with that formed by the piston rod 3 Wall of the cavity 40 is.
  • the electrical connection between the contact rod 41 and the evaluation unit 34 is established via an electrical line 33 ′′ indicated by a dot-dash line.

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  • Engineering & Computer Science (AREA)
  • 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)
  • Actuator (AREA)

Abstract

An actuator is proposed which has a piston rod (3) projecting from the cylinder (1) at least on one end face. Provided on the piston rod (3) at the periphery is at least one bearing surface (15) extending over a large part of its length and having a flat configuration. Firmly arranged on the bearing surface (15) is a measuring section (14) which extends in the longitudinal direction (12) of the piston rod (3) and can be scanned optically or electrically. In this way, the position of the piston rod (3) and/or of the piston connected to the piston rod (3) and arranged in the cylinder (1) can be reliably determined with relatively simple measures while ensuring a compact construction. <IMAGE>

Description

Die Erfindung betrifft ein Kolben-Zylinder-Aggregat, mit einer an mindestens einer Stirnseite aus dem Zylinder herausragenden Kolbenstange, und mit Mitteln zur Positionsbestimmung der Kolbenstange und/oder des mit dieser verbundenen und im Zylinder angeordneten Kolbens.The invention relates to a piston-cylinder unit, with a piston rod protruding from the cylinder on at least one end face, and with means for determining the position of the piston rod and / or the piston connected to it and arranged in the cylinder.

Die häufigste Maßnahme, bei Kolben-Zylinder-Aggregaten die Position des Kolbens und/oder der Kolbenstange zu bestimmen, besteht darin, am Kolben einen Permanentmagneten anzuordnen, der einen außen am Umfang des Zylinders festgelegten Sensor aufgrund seines Magnetfeldes berührungslos betätigen kann. Die Befestigung des Permanentmagneten am Kolben ist allerdings relativ aufwendig und erfordert oftmals besondere Abdichtungsmaßnahmen. Außerdem bewirkt der außen am Zylinder angeordnete Sensor eine Vergrößerung der Baubreite des Zylinders und beeinträchtigt dessen Befestigungsmöglichkeiten.The most common measure to determine the position of the piston and / or the piston rod in piston-cylinder units is to arrange a permanent magnet on the piston, which can actuate a sensor fixed on the outside of the circumference of the cylinder without contact due to its magnetic field. The attachment of the permanent magnet to the piston is, however, relatively complex and often requires special sealing measures. In addition, the sensor arranged on the outside of the cylinder causes an increase in the overall width of the cylinder and impairs its fastening options.

Es ist die Aufgabe der vorliegenden Erfindung, ein Kolben-Zylinder-Aggregat der eingangs genannten Art zu schaffen, das mit relativ einfachen Maßnahmen und unter Gewährleistung eines kompakten Aufbaus eine zuverlässige Positionsbestimmung ermöglicht.It is the object of the present invention to create a piston-cylinder unit of the type mentioned at the outset relatively simple measures and while ensuring a compact structure enables reliable position determination.

Diese Aufgabe wird dadurch gelöst, daß die Kolbenstange umfangsseitig mindestens eine sich über einen Großteil ihrer Länge erstreckende und Flachgestalt besitzende Tragfläche aufweist, an der eine sich in Längsrichtung der Kolbenstange erstreckende, optisch oder elektrisch abfragbare Meßstrecke fest angeordnet ist.This object is achieved in that the piston rod has on the circumference at least one supporting surface which extends over a large part of its length and has a flat shape and on which a measuring section which extends in the longitudinal direction of the piston rod and is optically or electrically interrogable is fixedly arranged.

Man verwendet also eine zumindest teilweise abgeflachte Kolbenstange als Träger für eine geeignete Meßstrecke. Infolge der Flachgestalt ist dabei eine präzise Abfrage oder Ablesung der Meßstrecke möglich. Gleichzeitig wird eine Verdrehsicherung erreicht, so daß die Meßstrecke immer gleiche Winkellage bezüglich des Zylinders einnimmt. Da die Meßstrecke einfach von außen her an die Kolbenstange angebracht ist, sind die Voraussetzungen für eine kostengünstige Herstellung gegeben.An at least partially flattened piston rod is therefore used as a carrier for a suitable measuring section. As a result of the flat shape, a precise interrogation or reading of the measuring section is possible. At the same time an anti-rotation lock is achieved so that the measuring section always assumes the same angular position with respect to the cylinder. Since the measuring section is simply attached to the piston rod from the outside, the prerequisites for economical manufacture are met.

Vorteilhafte Weiterbildungen der Erfindung sind in den Unteransprüchen aufgeführt.Advantageous developments of the invention are listed in the subclaims.

Es ist besonders vorteilhaft, als Kolbenstange eine Vierkantstange zu verwenden, wobei eine oder mehrere Tragflächen von einer entsprechenden Anzahl der vier umfangsseitig angeordneten Stangenflächen gebildet sind. Bei Bedarf kann man mehrere Meßstrecken in Umfangsrichtung versetzt an der Kolbenstange anbringen. Handelt es sich um eine im Querschnitt rechteckige und dabei insbesondere quadratische Vierkantstange, so ist die Herstellung besonders einfach und man erhält zugleich eine optimale Abstützung im Durchdringungsbereich des zugeordneten Zylinderdeckels. Die Stangenkanten können abgerundet sein.It is particularly advantageous to use a square rod as the piston rod, one or more wings being formed by a corresponding number of the four rod surfaces arranged on the circumference. If necessary, you can have several measuring sections Attach to the piston rod offset in the circumferential direction. If the square bar is rectangular in cross-section and in particular square, the manufacture is particularly simple and, at the same time, optimum support is obtained in the penetration area of the associated cylinder cover. The bar edges can be rounded.

Herstellungstechnisch besonders einfach und auch unkompliziert abfragbar ist eine Meßstrecke, die sich aus einer Vielzahl von in Längsrichtung der Kolbenstange mit Abstand aufeinanderfolgenden Markierungen zusammensetzt, die nach Art von Skalenstrichen ausgebildet sein können. Hier ist sowohl eine direkte visuelle Ablesung durch eine beobachtende Person möglich als auch der Einsatz eines optischen Sensors, der die vorbewegten Markierungen zu registrieren vermag und der insbesondere an dem von der Kolbenstange durchdrungenen Zylinderdeckel festgelegt wird.A measuring section which is particularly simple in terms of production technology and can also be queried in an uncomplicated manner is composed of a plurality of markings which follow one another in the longitudinal direction of the piston rod and which can be designed in the manner of scale marks. Here, a direct visual reading by an observer is possible as well as the use of an optical sensor, which is able to register the advancing markings and which is fixed in particular on the cylinder cover penetrated by the piston rod.

Die Markierungen bzw. Skalenstriche können in die Tragfläche insbesondere mechanisch eingeritzt und/oder eingeäzt und/oder durch Laserbestrahlung eingebracht worden sein. Dabei handelt es sich um äußerst feine Oberflächenvertiefungen, die im Durchdringungsbereich des zugeordneten Zylinderdeckels weder Undichtigkeiten noch einen Verschleiß vorhandener Dichtungseinrichtungen verursachen.The markings or scale lines can in particular have been mechanically incised and / or etched into the wing and / or introduced by laser radiation. These are extremely fine surface depressions that do not cause any leaks or wear of existing sealing devices in the penetration area of the assigned cylinder cover.

Als Meßstrecke kann auch ein Widerstandsstreifen vorgesehen sein, der sich entlang der Tragfläche erstreckt und entweder auf diese aufgesetzt und sie in eingelassen ist. Er wird von einem zylinderfest angeordneten Schleifkontakt beaufschlagt, so daß eine durch die Verlagerung des Widerstandsstreifens auftretende elektrische Widerstandsänderung registrierbar ist und Rückschlüsse auf die aktuelle Kolbenstangenposition zuläßt.A resistance strip can also be provided as the measuring section be, which extends along the wing and either placed on this and it is embedded in. It is acted upon by a sliding contact arranged fixed to the cylinder, so that an electrical change in resistance due to the displacement of the resistance strip can be registered and allows conclusions to be drawn about the current piston rod position.

Nachfolgend wird die Erfindung anhand der beiliegenden Zeichnung näher erläutert. In dieser sind mehrere Ausführungsbeispiele dargestellt. Im einzelnen zeigen:

Figur 1
eine erste Bauform des Kolben-Zylinder-Aggregates in perspektivischer Darstellung, wobei der Zylinder nur teilweise gezeigt ist und
Figur 2
eine zweite Ausführungsform im Längsschnitt und schematisiert, wobei in der Praxis vorhandene Dichtungs- und/oder Führungseinrichtungen zwischen Kolben bzw. Kolbenstange und Zylinder der Einfachheit halber nicht dargestellt sind.
The invention is explained in more detail below with reference to the accompanying drawing. Several exemplary embodiments are shown in this. In detail show:
Figure 1
a first design of the piston-cylinder unit in perspective, the cylinder is only partially shown and
Figure 2
a second embodiment in longitudinal section and schematic, wherein in practice existing sealing and / or guiding devices between the piston or piston rod and cylinder are not shown for the sake of simplicity.

Die Ausführungsbeispiele beider Figuren beinhalten einen Zylinder 1, in dem ein in Figur 1 nicht näher dargestellter Kolben 2 axial verschiebbar aufgenommen ist. An dem Kolben 2 sitzt eine Kolbenstange 3, die sich in Zylinderlängsrichtung erstreckt und einen Zylinderdeckel 4 durchdringt, der die eine Stirnseite des Zylinders 1 abschließt. Prinzipiell kann es sich um eine durchgehende Kolbenstange handeln, die dann auch den zweiten Zylinderdeckel 5 durchdringt (nicht dargestellt).The exemplary embodiments of both figures include a cylinder 1 in which a piston 2 (not shown in more detail in FIG. 1) is accommodated in an axially displaceable manner. On the piston 2 is a piston rod 3, which extends in the longitudinal direction of the cylinder and penetrates a cylinder cover 4, which closes one end of the cylinder 1. In principle, it can be a continuous piston rod which then also penetrates the second cylinder cover 5 (not shown).

In die vom Kolben 2 voneinander abgeteilten Zylinderräume 6, 7 münden Anschlußöffnungen 8, die in an sich bekannter Weise eine Zufuhr und/oder Abfuhr von Druckmittel erlauben, um den Kolben 2 zusammen mit der Kolbenstange 3 in Axialrichtung 12 hin und her zu verlagern. Vorliegend handelt es sich um ein pneumatisches Aggregat, das mit Druckluft betrieben wird.In the cylinder chambers 6, 7, which are separated from each other by the piston 2, connection openings 8 open, which in a manner known per se allow the supply and / or discharge of pressure medium in order to move the piston 2 together with the piston rod 3 back and forth in the axial direction 12. This is a pneumatic unit that is operated with compressed air.

Während des Betriebes des Aggregates ist es häufig erforderlich, die aktuelle Position des Kolbens und/oder der Kolbenstange zu ermitteln oder den von diesen zurückgelegten Weg, insbesondere in Bezug zum Zylinder 1, zu erfassen. Die Möglichkeit zu einer derartigen Positionsbestimmung ist im Falle der beiden Ausführungsbeispiele gegeben. Es ist dadurch beispielsweise möglich, in Abhängigkeit von bestimmten Positionen oder zurückgelegten Wegstrecken eine exakte Umsteuerung des Kolben-Zylinder-Aggregates selbst oder eine Ansteuerung externer Einrichtungen vorzunehmen. Daneben besteht natürlich auch die Möglichkeit, sich lediglich zur Information einen Überblick über die aktuelle Situation zu verschaffen.During the operation of the unit, it is often necessary to determine the current position of the piston and / or the piston rod or to record the distance traveled, in particular in relation to the cylinder 1. The possibility of such a position determination is given in the case of the two exemplary embodiments. This makes it possible, for example, to perform an exact reversal of the piston-cylinder unit itself or a triggering of external devices depending on specific positions or distances traveled. In addition, there is of course also the possibility to get an overview of the current situation for information only.

Beide in den Figuren gezeigten Kolben-Zylinder-Aggregate sind daher mit Mitteln 13 zur Positionsbestimmung der Kolbenstange ausgestattet. Zu diesen gehört eine Meßstrecke 14, die optisch oder elektrisch erfaßbar ist. Sie erstreckt sich in Längsrichtung 12 der Kolbenstange 3 und ist an einer an der Kolbenstange 3 ausgebildeten Tragfläche 15 befestigt. Die Tragfläche 15 bildet also praktisch einen Träger für die Meßstrecke 14 und erstreckt sich längsseits an der Kolbenstange 3 über mindestens einen Großteil deren Länge. Sie zeichnet sich dadurch aus, daß sie Flachgestalt besitzt und daher nicht, wie bei Kolbenstangen sonst üblich, mit gerundeter Kontur versehen ist. Abgesehen von einer am äußeren Endbereich der Kolbenstange 3 angeordneten Befestigungseinrichtung 16, die im Ausführungsbeispiel nach Art eines Gewindebolzens ausgebildet ist, erstreckt sich die Tragfläche 15 beispielsgemäß über die gesamte Länge der Kolbenstange 3 bis hin zum Kolben 2.Both piston-cylinder units shown in the figures are therefore equipped with means 13 for determining the position of the piston rod. These include a measuring section 14 which can be detected optically or electrically. It extends in the longitudinal direction 12 of the piston rod 3 and is fastened to a support surface 15 formed on the piston rod 3. The wing 15 thus practically forms a support for the measuring section 14 and extends along the piston rod 3 over at least a large part of its length. It is characterized in that it has a flat shape and is therefore not, as is usual with piston rods, provided with a rounded contour. Apart from a fastening device 16 arranged on the outer end region of the piston rod 3, which in the exemplary embodiment is designed like a threaded bolt, the supporting surface 15 extends over the entire length of the piston rod 3 as far as the piston 2, for example.

Die Meßstrecke 14 kann sich ebenfalls über diese gesamte Länge erstrecken, ist beim Ausführungsbeispiel allerdings etwas kürzer, so daß sie mit geringem Abstand vor sowohl der Befestigungseinrichtung 16 als auch dem Kolben 2 endet. Jedenfalls sollte sie zweckmäßigerweise so lang sein, daß sie sich zumindest annähernd über die gesamte Länge des bei vollständig ausgefahrener Kolbenstange 3 außerhalb des Zylinderdeckels 4 befindlichen Kolbenstangenabschnittes erstreckt.The measuring section 14 can also extend over this entire length, but is somewhat shorter in the exemplary embodiment, so that it ends at a short distance in front of both the fastening device 16 and the piston 2. In any case, it should expediently be so long that it extends at least approximately over the entire length of the piston rod section located outside the cylinder cover 4 when the piston rod 3 is fully extended.

Infolge der flachen Gestalt der Tragfläche 15 läßt sich die Meßstrecke 14 gut befestigen und zuverlässig ablesen. Außerdem wird automatisch eine Verdrehsicherung gegenüber dem Zylinder 1 erreicht, da die von der Kolbenstange 3 durchquerte Durchbrechung 17 eine zu der Kolbenstange 3 komplementäre Kontur besitzt. Zweckmäßigerweise ist die Kolbenstange 3 als Mehreckstange ausgebildet, wobei es sich im Falle der Ausführungsbeispiele um eine Vierkantstange handelt, die einen quadratischen Querschnitt besitzt. Die Tragfläche 15 ist dabei von einer der vier äußeren ebenen Stangenflächen gebildet.Due to the flat shape of the wing 15, the measuring section 14 fasten well and read reliably. In addition, an anti-rotation device with respect to the cylinder 1 is automatically achieved, since the opening 17 traversed by the piston rod 3 has a contour that is complementary to the piston rod 3. The piston rod 3 is expediently designed as a polygonal rod, which in the case of the exemplary embodiments is a square rod which has a square cross section. The wing 15 is formed by one of the four outer flat rod surfaces.

Es wäre prinzipiell auch möglich, mehrere der durch Kanten voneinander abgeteilten äußeren Stangenflächen als Tragflächen zu verwenden, die eine Meßstrecke tragen. Um größtmögliche Genauigkeit zu erzielen, ließen sich hierbei für die vorhandenen Meßstrecken sogar unterschiedliche Abfragearten vorsehen.In principle, it would also be possible to use several of the outer rod surfaces, which are separated from one another by edges, as wings which carry a measuring section. In order to achieve the greatest possible accuracy, different types of polling could even be provided for the existing measuring sections.

Im Falle des Ausführungsbeispiels gemäß Figur 1 setzt sich die Meßstrecke 14 aus einer Vielzahl von in Längsrichtung 12 der Kolbenstange 3 mit Abstand aufeinanderfolgenden Markierungen 18 zusammen. Vorzugsweise handelt es sich um strichähnlich gestaltete Markierungen 18, die jeweils quer zur Längsrichtung 12 der Kolbenstange 3 verlaufen, so daß die Meßstrecke 14 eine Art Skala darstellt. Diese läßt sich im Betrieb problemlos visuell durch einen Beobachter ablesen, um die aktuelle Relativposition zwischen der Kolbenstange 3 und dem Zylinder 1 zu erfahren. Zweckmäßig ist es, wenn eine zylinderfeste Bezugskante 19 vorhanden ist, an der die Markierungen 18 vorbeibewegt werden, und die ein exaktes reproduzierbares Ablesen ermöglicht. Beim Ausführungsbeispiel gemäß Figur 1 ist eine solche Bezugskante 19 unmittelbar von einer Körperkante des Zylinderdeckels 4 gebildet, und zwar dort, wo die Durchbrechung 17 axial nach außen mündet. Die Bezugskante 19 ist hier also die Abschlußkante des Zylinderdeckels 4 im Durchtrittsbereich der Kolbenstange 3.In the case of the exemplary embodiment according to FIG. 1, the measuring section 14 is composed of a plurality of markings 18 which follow one another in the longitudinal direction 12 of the piston rod 3 at a distance. These are preferably line-like markings 18, which each run transversely to the longitudinal direction 12 of the piston rod 3, so that the measuring section 14 represents a type of scale. This can easily be read visually by an observer during operation in order to find out the current relative position between the piston rod 3 and the cylinder 1. It is expedient if there is a cylinder-fixed reference edge 19 on which the markings 18 are moved past and which enables an exact reproducible reading. In the exemplary embodiment according to FIG. 1, such a reference edge 19 is formed directly by a body edge of the cylinder cover 4, specifically where the opening 17 opens out axially. The reference edge 19 is thus the end edge of the cylinder cover 4 in the passage area of the piston rod 3.

Es ist möglich, einen in Figur 1 strichpunktiert angedeuteten optischen Sensor 22 vorzusehen, der sich zweckmäßigerweise außerhalb des Zylinders 1 befindet. Beispielsgemäß sitzt er an der Stirnseite des der Kolbenstange 3 zugeordneten Zylinderdeckels 4. Er ragt über die Tragfläche 15 und ist so ausgebildet, daß er die vorbeibewegten Markierungen 18 lesen und/oder zählen kann. Jede vorbeibewegte Markierung 18 löst einen elektrischen Impuls aus, der über eine Signalleitung 23 zu einer Auswerteinheit 24 gelangt. Dort werden die Signale ausgewertet, so daß beispielsweise eine optische Anzeige der aktuellen Position und der zurückgelegten Wegstrecke möglich ist. Es versteht sich, daß die erhaltenen Signale beliebig verwertbar sind.It is possible to provide an optical sensor 22, indicated by dash-dotted lines in FIG. 1, which is expediently located outside the cylinder 1. For example, it sits on the end face of the cylinder cover 4 assigned to the piston rod 3. It protrudes over the wing 15 and is designed such that it can read and / or count the markings 18 that have passed. Each marker 18 that is moved past triggers an electrical pulse that arrives at an evaluation unit 24 via a signal line 23. The signals are evaluated there so that, for example, an optical display of the current position and the distance covered is possible. It goes without saying that the signals obtained can be used as desired.

Ein besonders einfacher und verschleißarmer Aufbau ergibt sich, wenn die Markierungen 18 in die Kolbenstange 3 eingeritzt sind. Dies kann mittels geeigneten scharfkantigen Werkzeugen geschehen. Möglich ist es aber auch, diese Markierungen durch Ätzen oder mittels Laserstrahlen in die Tragfläche 15 einzubringen. Vor allem die beiden letztgenannten Maßnahmen gewährleisten, daß die Markierungstiefe sehr gering ist. Man erzielt dadurch eine optimale Ablesbarkeit bei gleichzeitiger Vermeidung von Dichtproblemen im Durchdringungsbereich 17 des Zylinderdeckels 4. Die Markierungstiefen sind so gering, daß eine dort angeordnete Dichtungseinrichtung nicht beschädigt wird. Undichtigkeiten sind ausgeschlossen, da die Vertiefungen quer verlaufen, so daß keine Verbindung zwischen der Umgebung und dem sich innen anschließenden Zylinderraum 7 besteht.A particularly simple and low-wear construction results if the markings 18 are incised in the piston rod 3. This can be done using suitable sharp-edged tools. However, it is also possible to introduce these markings into the wing 15 by etching or by means of laser beams. In front All of the latter two measures ensure that the depth of marking is very small. Optimal readability is thereby achieved while avoiding sealing problems in the penetration area 17 of the cylinder cover 4. The depths of the mark are so small that a sealing device arranged there is not damaged. Leaks are excluded, since the depressions run transversely, so that there is no connection between the surroundings and the cylinder space 7 adjoining on the inside.

Im Falle der Bauform gemäß Figur 2 liegt die Meßstrecke 14 als elektrischer Widerstandsstreifen 25 vor. Dieser ist beispielsgemäß mit der Kolbenstange 3 verklebt, was sich als Beste der möglichen festen Verbindungsarten herausgestellt hat. Zwar kann der Widerstandsstreifen 25 erhaben auf die Tragfläche 15 aufgesetzt sein. Die Abdichtung im Durchdringungsbereich des Zylinderdeckels 4 läßt sich jedoch erheblich besser in den Griff bekommen, wenn er, wie aus Figur 2 hervorgeht, in der Tragfläche 15 versenkt zu liegen kommt. Hierzu besitzt die Tragfläche 15 eine Längsnut 26 geeigneter Tiefe, in der Widerstandsstreifen 25 eingelegt ist. Die nach außen weisende Oberfläche des Widerstandsstreifens 25 bildet eine Gleitfläche 27, die vorzugsweise bündig in die angrenzenden Oberflächenbereiche der Tragfläche 15 übergeht.In the case of the design according to FIG. 2, the measuring section 14 is in the form of an electrical resistance strip 25. This is glued to the piston rod 3, for example, which has been found to be the best of the possible fixed connection types. The resistance strip 25 can be raised on the wing 15. The seal in the penetration area of the cylinder cover 4 can, however, be handled much better if, as can be seen in FIG. 2, it comes to lie sunk in the wing 15. For this purpose, the wing 15 has a longitudinal groove 26 of suitable depth, in which the resistance strip 25 is inserted. The outward-facing surface of the resistance strip 25 forms a sliding surface 27, which preferably merges flush with the adjacent surface regions of the supporting surface 15.

Der Widerstandsstreifen 25 ist beim Ausführungsbeispiel gegenüber der Kolbenstange 3 elektrisch isoliert, die vorliegend aus elektrisch leitendem Material wie Aluminium-Material oder Stahl besteht. Die Isolation erfolgt z.B. durch Zwischenfügen einer gespeicherten Isolationsschicht 30. Lediglich mit einem seiner beiden axialen Endbereiche, vorliegend dem außerhalb des Zylinders 1 liegenden Endbereich 28, steht der Widerstandsstreifen 25 in elektrisch leitender Verbindung mit der Kolbenstange 3. Die Verbindungsstelle ist bei 29 angedeutet.The resistance strip 25 is opposite in the exemplary embodiment the piston rod 3 is electrically insulated, which in the present case consists of an electrically conductive material such as aluminum material or steel. The insulation is carried out, for example, by interposing a stored insulation layer 30. Only with one of its two axial end regions, in the present case the end region 28 lying outside the cylinder 1, is the resistance strip 25 in an electrically conductive connection with the piston rod 3. The connection point is indicated at 29.

Desweiteren ist ein erster Schleifkontakt 32 vorgesehen, der isoliert am Zylinder 1 befestigt ist und insbesondere an einem die Kolbenstange 3 umschließenden Axialvorsprung 39 des Zylinderdeckels 4 sitzt. Der Schleifkontakt 32 steht einerseits unter federnder Vorspannung in Berührkontakt mit der Gleitfläche 27. Andererseits ist er über eine elektrische Leitung 33 an eine Auswerteeinheit 34 angeschlossen. Ein zweiter Schleifkontakt 35 ist ebenfalls elektrisch isoliert am Zylinderdeckel 4 angebracht und steht unter federnder Vorspannung in Berührkontakt mit einem neben dem Widerstandsstreifen 25 liegenden Abschnitt der Kolbenstange 3. Beispielsgemäß handelt es sich bei dem genannten Abschnitt der Kolbenstange um eine (36) der Stangenflächen, die nicht als Tragflächen verwendet wird. Es bietet sich an, die der Tragfläche 15 diametral entgegengesetzte Stangenfläche 36 als Kontaktfläche für den zweiten Schleifkontakt 35 zu verwenden.Furthermore, a first sliding contact 32 is provided, which is fastened in an insulated manner to the cylinder 1 and, in particular, is seated on an axial projection 39 of the cylinder cover 4 that surrounds the piston rod 3. The sliding contact 32 is on the one hand under resilient prestress in contact with the sliding surface 27. On the other hand, it is connected via an electrical line 33 to an evaluation unit 34. A second sliding contact 35 is also mounted on the cylinder cover 4 in an electrically insulated manner and is in spring-loaded prestress in contact with a section of the piston rod 3 located next to the resistance strip 25 is not used as wings. It makes sense to use the rod surface 36 diametrically opposite the support surface 15 as the contact surface for the second sliding contact 35.

Auch der zweite Schleifkontakt 35 steht über eine elektrische Leitung 33' mit der Auswerteeinheit 34 in Verbindung.The second sliding contact 35 is also connected to the evaluation unit 34 via an electrical line 33 '.

Der elektrische Widerstand des Widerstandsstreifens 25 wird so gewählt, daß derjenige der Kolbenstange 3 und auch die Übergangswiderstände zu den Schleifkontakten 32, 35 vernachlässigbar gering sind. Nun wird an die beiden elektrischen Leitungen 33, 33' eine Spannung angelegt, die einen Stromfluß erzeugt. Der Strom fließt von der elektrischen Leitung 33' zum zweiten Schleifkontakt 35, von dort zur Kolbenstange 3 und in dieser zur Verbindungsstelle 29, im weiteren entlang des Widerstandsstreifens 25 bis zur Berührstelle 37 des ersten Schleifkontaktes 32, und sodann über diesen ersten Schleifkontakt 32 und die elektrische Leitung 33 zurück zur Auswerteeinheit 32, wo sich die Spannungsquelle befindet. Maßgeblich für die Stromstärke ist dabei der jeweils wirkende elektrische Widerstand, der durch den Widerstands-streifen 25 erzeugt wird. Dieser wird bestimmt durch die axiale Länge des momentan zwischen der Verbindungsstelle 29 und der Berührstelle 37 des ersten Schleifkontaktes 32 liegenden Streifenabschnittes 38. Der Streifenabschnitt 38 ist um so länger, je weiter die Kolbenstange 3 ausgefahren ist, und dementsprechend erhöht sich der elektrische Widerstand, was in der Auswerteeinheit 35 als Stromänderung registrierbar ist. Wenn sich die Kolbenstange 3 axial bewegt, schleifen die beiden Schleifkontakte 32, 35 an der Gleitfläche 27 und an der Stangenfläche 36 entlang.The electrical resistance of the resistance strip 25 is chosen so that that of the piston rod 3 and also the contact resistance to the sliding contacts 32, 35 are negligible. Now a voltage is applied to the two electrical lines 33, 33 ', which generates a current flow. The current flows from the electrical line 33 'to the second sliding contact 35, from there to the piston rod 3 and in this to the connecting point 29, further along the resistance strip 25 to the contact point 37 of the first sliding contact 32, and then via this first sliding contact 32 and the electrical line 33 back to the evaluation unit 32, where the voltage source is located. The relevant electrical resistance, which is generated by the resistance strip 25, is decisive for the current strength. This is determined by the axial length of the strip section 38 currently lying between the connection point 29 and the contact point 37 of the first sliding contact 32. The strip section 38 is longer the further the piston rod 3 is extended, and accordingly the electrical resistance increases, which can be registered in the evaluation unit 35 as a current change. When the piston rod 3 moves axially, the two sliding contacts 32, 35 grind along the sliding surface 27 and along the rod surface 36.

Basierend auf den ermittelten Werten vermag die Auswerteeinheit 34 die aktuelle Position und/oder den zurückgelegten Weg der Kolbenstange 3 in Bezug zum Zylinder 1 festzustellen und auch anzuzeigen. In Abhängigkeit von bestimmten Werten können dann auch weitere Schaltfunktionen ausgelöst werden.Based on the determined values, the evaluation unit 34 is able to determine the current position and / or the distance traveled by the piston rod 3 in relation to the cylinder 1 also display. Depending on certain values, further switching functions can then also be triggered.

Das geschilderte Potentiometermeßprinzip würde auch dann funktionieren, wenn man die Verbindungsstelle 29 zum axial innen liegenden Ende des Widerstandsstreifens 25 verlegt.The described potentiometer measuring principle would also work if the connection point 29 is moved to the axially inner end of the resistance strip 25.

Die beispielsgemäß verwendeten Schleifkontakte 32, 35 sind federnde Metallbleche, die ausgehend vom Zylinderdeckel 4 schräg nach axial außen und zugleich in Richtung zur Kolbenstange 3 verlaufen. Denkbar wäre es auch, Schleifkontakte zu verwenden, die exakt radial gegen die Kolbenstange 3 bzw. den Widerstandsstreifen 25 angedrückt werden und insbesondere unter der Vorspannung einer Federanordnung stehen. Es wäre möglich, diese Schleifkontakte in den beispielsgemäß vorgesehenen, die Kolbenstange 3 koaxial umschließenden Axialvorsprung 39 an der Außenseite des Zylinderdeckels 4 zu integrieren.The sliding contacts 32, 35 used according to the example are resilient metal sheets which, starting from the cylinder cover 4, run obliquely outwards axially and at the same time in the direction of the piston rod 3. It would also be conceivable to use sliding contacts which are pressed exactly radially against the piston rod 3 or the resistance strip 25 and in particular are under the pretension of a spring arrangement. It would be possible to integrate these sliding contacts in the axial projection 39 provided according to the example and coaxially surrounding the piston rod 3 on the outside of the cylinder cover 4.

Denkbar wäre es auch, die Kolbenstange 3 im Zylinderinnern abzugreifen. In diesem Falle würde man, wie dies strichpunktiert angedeutet ist, die Kolbenstange 3 mit einem sich axial erstreckenden Hohlraum 40 versehen, der zum Zylinderdeckel 5 hin offen ist. Ein an diesem Zylinderdeckel 4 insbesondere isoliert befestigter Kontaktstab 41 ragt dann axial in den Hohlraum 40 hinein und trägt einen Schleifkontakt 35', der in elektrisch leitender Schleifverbindung mit der von der Kolbenstange 3 gebildeten Wandung des Hohlraumes 40 steht. Über eine strichpunktiert angedeutete elektrische Leitung 33'' wird die elektrische Verbindung zwischen dem Kontaktstab 41 und der Auswerteeinheit 34 hergestellt. Es können nun der oben erläuterte zweite Schleifkontakt 35 und die zugehörige elektrische Leitung 33' entfallen.It would also be conceivable to tap the piston rod 3 inside the cylinder. In this case, as indicated by dash-dotted lines, the piston rod 3 would be provided with an axially extending cavity 40 which is open towards the cylinder cover 5. A contact rod 41, which is attached to this cylinder cover 4 in a particularly insulated manner, then projects axially into the cavity 40 and carries a sliding contact 35 ′, which is in an electrically conductive sliding connection with that formed by the piston rod 3 Wall of the cavity 40 is. The electrical connection between the contact rod 41 and the evaluation unit 34 is established via an electrical line 33 ″ indicated by a dot-dash line. The second sliding contact 35 explained above and the associated electrical line 33 'can now be omitted.

Claims (10)

Kolben-Zylinder-Aggregat, mit einer an mindestens einer Stirnseite aus dem Zylinder herausragenden Kolbenstange und mit Mitteln zur Positionsbestimmung der Kolbenstange und/oder des mit dieser verbundenen und im Zylinder angeordneten Kolbens, dadurch gekennzeichnet, daß die Kolbenstange (3) umfangsseitig mindestens eine sich über einen Großteil ihrer Länge erstreckende und Flachgestalt besitztende Tragfläche (15) aufweist, an der eine sich in Längsrichtung (12) der Kolbenstange (3) erstreckende, optisch oder elektrisch abfragbare Meßstrecke (14) fest angeordnet ist.Piston-cylinder unit, with a piston rod protruding from the cylinder on at least one end face and with means for determining the position of the piston rod and / or the piston connected to it and arranged in the cylinder, characterized in that the piston rod (3) has at least one circumferential side Has a wing (15) which extends over a large part of its length and has a flat shape, on which an optically or electrically interrogable measuring section (14) extending in the longitudinal direction (12) of the piston rod (3) is fixed. Kolben-Zylinder-Aggregat nach Anspruch 1, dadurch gekennzeichnet, daß die Kolbenstange (3) eine Vierkantstange mit insbesondere quadratischem Querschnitt ist, wobei die Tragfläche (15) von einer der vier Stangenflächen gebildet ist.Piston-cylinder unit according to claim 1, characterized in that the piston rod (3) is a square rod with a square cross section in particular, the supporting surface (15) being formed by one of the four rod surfaces. Kolben-Zylinder-Aggregat nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß sich die Meßstrecke (14) aus einer Vielzahl von in Längsrichtung (12) der Kolbenstange (3) mit Abstand aufeinanderfolgenden Markierungen (18) zusammensetzt.Piston-cylinder unit according to claim 1 or 2, characterized in that the measuring section (14) consists of a plurality of the successive markings (18) in the longitudinal direction (12) of the piston rod (3). Kolben-Zylinder-Aggregat nach Anspruch 3, dadurch gekennzeichnet, daß die Markierungen mechanisch in die Tragfläche (15) eingeritzte Markierungen (18) sind.Piston-cylinder unit according to Claim 3, characterized in that the markings are markings (18) which are mechanically incised in the wing (15). Kolben-Zylinder-Aggregat nach Anspruch 3, dadurch gekennzeichnet, daß die Markierungen in die Tragfläche eingeätzte Markierungen (18) sind.Piston-cylinder unit according to claim 3, characterized in that the markings are markings (18) etched into the wing. Kolben-Zylinder-Aggregat nach Anspruch 3, dadurch gekennzeichnet, daß die Markierungen durch Laserstrahl in die Tragfläche (15) eingebrannte Markierungen (18) sind.Piston-cylinder unit according to Claim 3, characterized in that the markings are burned-in markings (18) by a laser beam in the wing (15). Kolben-Zylinder-Aggregat nach einem der Ansprüche 3 bis 6, dadurch gekennzeichnet, daß die Markierungen (18) strichförmig ausgebildet sind und jeweils quer zur Längsrichtung (12) der Kolbenstange (3) verlaufen, wobei die Meßstrecke (14) eine Meßskala sein kann.Piston-cylinder unit according to one of Claims 3 to 6, characterized in that the markings (18) are in the form of lines and each run transversely to the longitudinal direction (12) of the piston rod (3), it being possible for the measuring section (14) to be a measuring scale . Kolben-Zylinder-Aggregat nach einem der Ansprüche 3 bis 7, dadurch gekennzeichnet, daß neben der Kolbenstange (3) im Bereich der Tragfläche (15) ein optischer Sensor (22) angeordnet ist, der die vorbeibewegten Markierungen (18) registriert.Piston-cylinder unit according to one of claims 3 to 7, characterized in that an optical sensor (22) is arranged next to the piston rod (3) in the region of the wing (15), which registers the markings (18) moved past. Kolben-Zylinder-Aggregat nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Meßstrecke (14) ein entlang der Tragfläche (15) verlegter und insbesondere versenkt in dieser aufgenommener Widerstandsstreifen (25) ist, der von einem zylinderfesten Schleifkontakt (32) beaufschlagt wird.Piston-cylinder unit according to Claim 1 or 2, characterized in that the measuring section (14) is a resistance strip (25) which is laid along the support surface (15) and in particular recessed therein, which is acted upon by a cylinder-fixed sliding contact (32) . Kolben-Zylinder-Aggregat nach Anspruch 9, dadurch gekennzeichnet, daß der Widerstandsstreifen (25) an einem seiner Endbereiche (28) in elektrisch leitendem Kontakt mit der Kolbenstange (3) steht und dieser gegenüber im übrigen elektrisch isoliert ist, wobei ein zweiter Schleifkontakt (35, 35') die Kolbenstange (3) abgreift und beide Schleifkontakte (32; 35, 35') an eine Auswerteeinheit (34) angeschlossen sind.Piston-cylinder unit according to Claim 9, characterized in that the resistance strip (25) is in electrically conductive contact with the piston rod (3) at one of its end regions (28) and is otherwise electrically insulated from the latter, a second sliding contact ( 35, 35 ') picks up the piston rod (3) and both sliding contacts (32; 35, 35') are connected to an evaluation unit (34).
EP93107873A 1992-07-24 1993-05-14 Actuator Expired - Lifetime EP0591614B1 (en)

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DE9209980U DE9209980U1 (en) 1992-07-24 1992-07-24 Piston-cylinder unit
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WO2009053812A2 (en) * 2007-10-22 2009-04-30 A.M.A. S.P.A. System for determining the position of a piston along its path of travel for a fluid-dynamic actuator

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DE4403639A1 (en) * 1994-02-05 1995-08-10 Festo Kg Fluidically actuated feed unit
DE9412435U1 (en) * 1994-08-02 1994-09-29 Festo Kg, 73734 Esslingen Working cylinder
DE29713546U1 (en) * 1997-07-30 1997-09-25 Festo AG & Co, 73734 Esslingen Optical path and / or position sensor arrangement
DE29713825U1 (en) * 1997-08-02 1997-10-02 Festo Kg, 73734 Esslingen Fluid operated cylinder
CN105402197B (en) * 2016-01-06 2018-01-09 安徽珂力智能电气有限公司 A kind of cylinder of cubic cylindricality piston rod
US11828306B2 (en) 2021-04-30 2023-11-28 Industries Mailhot Inc. Method and a system for position measurement of a piston rod of a hydraulic cylinder

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US3096497A (en) * 1961-03-06 1963-07-02 Ling Temco Vought Inc Combination hydraulic actuator and potentiometer
FR2233512A1 (en) * 1973-06-14 1975-01-10 Repiquet Sa Vice with controlled displacement - has plastic marks on stem for photodetector
FR2343909A1 (en) * 1976-03-12 1977-10-07 Outillage Air Comprime Valve piston position monitoring device - has detector opposite grooves on spindle connected by optical fibre light guide to actuator
GB2062124A (en) * 1979-10-22 1981-05-20 Secretary Industry Brit Fluid driven oscillator and hammer device
DE3535704A1 (en) * 1985-10-05 1987-04-09 Festo Kg PISTON CYLINDER ARRANGEMENT
DE8627037U1 (en) * 1986-10-11 1987-01-08 Hügler, Klaus, 73614 Schorndorf Working cylinders, especially pneumatic cylinders for components of handling machines

Cited By (8)

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Publication number Priority date Publication date Assignee Title
EP0941812A1 (en) * 1998-03-10 1999-09-15 Novartec, Ltd. Ram device with a fluid pump and press tool
EP0941813A1 (en) * 1998-03-10 1999-09-15 Novartec AG Press tool and pressing process for crimping fittings
CN100342143C (en) * 2004-07-22 2007-10-10 杨世祥 Two-stage screw internal foodback digital fluid cylinder
EP2042412A2 (en) 2007-09-26 2009-04-01 BPW Bergische Achsen KG Actuation element for axle lifts and retrofit kit for axle lift actuation elements
EP2042412A3 (en) * 2007-09-26 2009-09-30 BPW Bergische Achsen KG Actuation element for axle lifts and retrofit kit for axle lift actuation elements
WO2009053812A2 (en) * 2007-10-22 2009-04-30 A.M.A. S.P.A. System for determining the position of a piston along its path of travel for a fluid-dynamic actuator
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
US8776667B2 (en) 2007-10-22 2014-07-15 A.M.A. S.P.A. System for determining the position of a piston along its path of travel for a fluid-dynamic actuator

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DE59304878D1 (en) 1997-02-06
DE9209980U1 (en) 1992-09-24

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