EP0141215B1 - Fluid pressure actuator having a piston cushioning device in final positions - Google Patents

Fluid pressure actuator having a piston cushioning device in final positions Download PDF

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Publication number
EP0141215B1
EP0141215B1 EP84111136A EP84111136A EP0141215B1 EP 0141215 B1 EP0141215 B1 EP 0141215B1 EP 84111136 A EP84111136 A EP 84111136A EP 84111136 A EP84111136 A EP 84111136A EP 0141215 B1 EP0141215 B1 EP 0141215B1
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EP
European Patent Office
Prior art keywords
piston
working
auxiliary
chamber
cylinder
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.)
Expired
Application number
EP84111136A
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German (de)
French (fr)
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EP0141215A1 (en
Inventor
Heinrich Dr. Kedzierski
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.)
Wabco Westinghouse Steuerungstechnik and Co GmbH
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Wabco Westinghouse Steuerungstechnik and Co GmbH
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Application filed by Wabco Westinghouse Steuerungstechnik and Co GmbH filed Critical Wabco Westinghouse Steuerungstechnik and Co GmbH
Priority to AT84111136T priority Critical patent/ATE25279T1/en
Publication of EP0141215A1 publication Critical patent/EP0141215A1/en
Application granted granted Critical
Publication of EP0141215B1 publication Critical patent/EP0141215B1/en
Expired legal-status Critical Current

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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
    • F15B15/26—Locking mechanisms
    • F15B15/262—Locking mechanisms using friction, e.g. brake pads
    • 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
    • F15B15/22—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke
    • F15B15/227—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke having an auxiliary cushioning piston within the main piston or the cylinder end face

Definitions

  • the invention relates to a pressure-actuated working cylinder with a device for damping the end braking of the working piston according to the preamble of patent claim 1.
  • Such a double-acting cylinder is previously known from DE-A-3146 998.
  • the working piston is braked in its two end positions in such a way that the damping chamber is in one end position by a piston-like projection of one cylinder cover and a corresponding recess of the working piston and in the other end position by a piston-like projection of the working piston and a corresponding recess other cylinder cover is formed.
  • This working cylinder can thus only be braked in its two end positions and not in any intermediate position.
  • working pistons which serve as so-called positioning cylinders
  • a working cylinder i.e. stopping in an arbitrarily selectable intermediate position of the working piston
  • a braking device known from US-A-4,073,217
  • the working piston has on its jacket a pressure-medium-actuated, wedge-shaped actuation aid for radially movable brake elements, which can be brought into frictional engagement with the cylinder inner wall.
  • the invention is therefore based on the object of creating a pressure-actuated working cylinder of the type mentioned which, by simple means, enables precise positioning in any possible intermediate position of the working piston with adequate damping acting at the same time.
  • the invention has the advantage that only the additional piston has to be stopped for the exact positioning.
  • the position of the additional piston can be detected in a simple manner with the usual, known sensors.
  • the additional piston which has a comparatively low mass, is then braked in a control loop or with a target control and fixed in the desired position. It is easily possible to fix the additional piston with the required parking brake forces.
  • the working piston of the working cylinder then runs with its mass and the mass of the parts moved by it against the additional piston thus fixed, which then forms a fixed wall. This final braking of the working piston is then damped in a manner known per se.
  • the position of the working piston can also be exactly predetermined.
  • the two functions “positioning” and “end deceleration” are separated to a certain extent, and each is implemented in the optimal manner.
  • the drawing shows a double-acting cylinder that can be used as a positioning cylinder.
  • a working piston is guided in a sealed manner in a cylinder tube 48, which is closed at its ends by a cover 60 sealed by a seal 3 and a cover 27 sealed by a seal 33.
  • This working piston sits on the stepped section 15 of a piston rod 30 and comprises two piston parts 43 and 45, between which a piston wall 14 is arranged, which in turn carries a piston seal 13.
  • the piston serving as the working piston is named with the reference number of the piston wall 14.
  • a nut 57 which can be screwed onto a corresponding thread of the piston rod 30, is provided for fastening the piston 14 to the section 15 of the piston rod 30, a sleeve 55, the piston part 45 and the piston wall 14 being between this nut 57 and a shoulder 22 of the piston rod 30 , the piston part 43 and a further sleeve 20 are clamped.
  • an additional piston 49 is arranged, which surrounds the sleeve 55 and the piston part 45 in a ring and on the one hand by means of a seal 10 against the inner wall of the cylinder tube 48 and on the other hand by means of a between the Piston part 45 and the sleeve 55 arranged seal 11 is sealed against the piston 14.
  • the additional piston 49 rests under the tension of a spring 46 on a shoulder 61 of the sleeve 55, so that it can be moved axially relative to the piston 14 against the force of the spring 46.
  • the spring 46 designed as a compression spring is supported on the one hand on the piston wall 14 and on the other hand on a shoulder 47 of the additional piston 49.
  • the seal 11 is designed as a check valve so that the chamber 12 between the piston 14 and the additional piston 49, which serves as a damping chamber, can be acted upon by the check valve 11 with the pressure of the working pressure chamber 5 lying between the cover 60 and the additional piston 49.
  • a further additional piston 19 is provided on the right side of the piston 14, which surrounds the sleeve 20 and the piston part 43 in an annular manner and rests against a projection 21 of the sleeve 20 under the tension of a spring 42.
  • the spring 42 designed as a compression spring is arranged between the piston wall 14 and a shoulder 16 of the additional piston 19.
  • the additional piston 19 is sealed off from the inner wall of the cylinder tube 48 by means of a seal 18.
  • the sealing against the piston part 43 and thus against the piston 14 takes place by means of a seal 17 which is arranged between the piston part 43 and the sleeve 20.
  • the seal 17 serves as a check valve, via which the pressure between the working pressure chamber 35 located between the cover 27 and the additional piston 19 can be applied to the chamber 44 located between the piston 14 and the additional piston 19 and provided as a damping chamber. It can be seen that the additional piston 19 can be moved axially relative to the piston 14 in accordance with the additional piston 49.
  • a compressed air connection 59 is provided in the cover 60, which is connected to the working pressure chamber 5 via a bore 58.
  • the compressed air connection 59 is pressurized with compressed air via a compressed air line (not shown)
  • the working pressure chamber 5 and the damping chamber 12 are pressurized with compressed air, so that the piston 14 can be moved to the right.
  • the force of the spring 42 is so large that in the described operating state the additional piston 19 can also be moved to the right in the position shown relative to the piston 14.
  • a further compressed air connection 31 is provided, which is connected to the working pressure chamber 35 via a bore 32.
  • the working pressure chamber 35 and the damping chamber 44 are filled with compressed air, so that the piston 14 with the additional piston 19 is then moved to the left.
  • the force of the spring 46 is dimensioned such that, in the operating state described last, the other additional piston 49 remains in the position shown relative to the piston 14.
  • the cover 60 has a further compressed air connection 1, which is connected via a bore 2 to a line connection 4 arranged in the working pressure chamber 5.
  • the line connection 4 is connected via a flexible, helical compressed air line 56 to a further line connection 54, which is arranged on the additional piston 49.
  • the line connection 54 is connected via a bore 53 of the additional piston 49 to a brake pressure chamber 52 of the additional piston 49.
  • the brake pressure chamber 52 is closed off from the inner wall of the cylinder tube 48 by an elastic membrane 51, which can bulge outward in the manner of a bellows when the brake pressure chamber 52 is pressurized.
  • a plurality of brake elements 50 distributed over the circumference of the additional piston 49, possibly forming a single part, which can be moved radially outward so that they can be brought into frictional engagement with the inner wall of the cylinder tube 48.
  • Corresponding brake elements 40 are arranged on the additional piston 19, which lie between the inner wall of the cylinder tube 48 and an elastic membrane 38.
  • the membrane 38 closes a brake pressure chamber 39, which connects a bore 25 in the cover 27 to a corresponding compressed air connection 26 via a bore 37 and a line connection 36 of the additional piston 19 as well as a flexible, helical compressed air line 23, a line connection 24 arranged in the working pressure chamber 35 is.
  • the braking elements 40 can be brought into frictional engagement with the inner wall of the cylinder tube 48 by means of compressed air supply to the compressed air connection 26.
  • the brake pressure chambers 39 and 52 are each connected to the associated damping chamber 44 or 12 via a check valve, the check valve opening towards the brake pressure chamber.
  • this check valve is shown only symbolically as valve 41 in the additional piston 19.
  • a corresponding check valve is arranged in the additional piston 49, where it forms a connection between the damping chamber 12 and the brake pressure chamber 52.
  • the additional piston 49 has further bores 8 and 9, between which a throttle 7 adjustable by means of a screw is arranged.
  • a throttle 7 adjustable by means of a screw Via this throttle device or throttle line 7, 8, 9, the damping chamber 12 is connected to an annular chamber 6 surrounding the sleeve 55, which in turn is connected to the working pressure chamber 5.
  • the check valve formed by the annular lip seal 11 and opening towards the damping chamber 12 is bridged by the throttle device 7, 8, 9.
  • a corresponding throttle device for bridging the check valve formed by the annular lip seal 15 and opening towards the damping chamber 44 is provided in the additional piston 19. To simplify the drawing, this throttle device for the additional piston 19 is not shown.
  • the double-acting working cylinder described so far and shown in the drawing with a greatly reduced length works as follows: It is assumed that the piston 14 is moved from the position shown to the right until it has reached a predetermined position. The predetermined position is to be reached or approached in such a way that the interruption of the movement of the piston and thus the interruption of the movement of the masses driven by the piston is damped.
  • a compressed air control system (not shown) with corresponding valves first applies compressed air to the compressed air connection 59. This means that the working pressure chamber 5 and the damping chamber 12 are also acted upon by compressed air. As soon as the actuating force generated in this way on the piston 14 in the right direction overcomes the oppositely directed resistance forces (friction, load, etc.), the piston 14 is moved accelerated to the right. When the piston 14 moves to the right, it is checked in a manner not shown whether or when the additional piston 19 is in the predetermined position or whether or when the piston 14 is in one of the predetermined positions or whether or when the piston 14 is in one of the approaching predetermined position upstream corresponding position or this reached.
  • the compressed air connection 26 is acted upon by compressed air via the aforementioned compressed air control system.
  • the brake pressure chamber 39 is then pressurized with compressed air via the path of the compressed air comprising the compressed air line 23.
  • the braking elements 40 are brought into frictional engagement with the inner wall of the cylinder tube 48 and the additional piston 19 is stopped. Because of the relatively small mass of the additional piston 19 and the comparatively small-volume compressed air lines for actuating the brake pressure chamber 39, the additional piston 19 is stopped very quickly and very precisely.
  • the additional piston 19 fixed in this way then forms, to a certain extent, a fixed wall on the side of the piston 14 not acted upon by the working pressure, which delimits the steaming chamber 44.
  • the application of compressed air to the working pressure chamber 5 can be interrupted.
  • the piston 14 will - due to its and the masses moved by it - then continue to run to the right.
  • the volume of the damping chamber 44 is then reduced and the pressure in this damping chamber 44 is increased accordingly, since the lip seal 17 prevents venting of the damping chamber 44.
  • a pressure relief or venting of the damping chamber 44 takes place only via the throttle device (not shown) (corresponding to the throttle device 7, 8, 9 of the additional piston 49) and the check valve 41.
  • the damping chamber 44 is thus throttled vented due to the dynamic processes. This means that the movement of the piston 14 is braked in a damped manner. With a corresponding dimensioning of the throttle device adapted to the usual load and speed of movement of the piston 14, the piston 14 will finally come to rest on the additional piston 19 and thus reach the predetermined position in a damped manner.
  • damping device for the piston 14 is formed by a piston-like projection of the working piston or the additional piston and a recess of the additional piston or the working piston, the recess serving for the sealed reception of the piston-like projection.
  • the throttled venting of the damping chamber takes place in a manner similar to that in the exemplary embodiment described.
  • the damping chamber can also be formed instead of directly from the working piston by a pressure piece arranged on the corresponding side of the working piston and non-positively connected to the working piston.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Braking Arrangements (AREA)
  • Actuator (AREA)

Abstract

A fluid-pressure-operated, double-acting working cylinder which dampens the final braking of the work piston, includes a cylinder housing with a movable work piston disposed therein, the work piston dividing the cylinder into two work chambers. A piston rod, on which the work piston is mounted, extends through the housing. At least one auxiliary braking member is disposed on at least one side of the work piston in an offset slidable relation to the work piston. A braking arrangement disposed on the auxiliary braking member is controlled by fluid pressure to brake the auxiliary braking member to a desired position within the cylinder. A dampening chamber, a dampening spring configuration is disposed between the auxiliary braking member work piston such that, following braking of the auxiliary braking member, continued movement of the work piston is effectively dampened. An auxiliary check valve formed in the auxiliary braking member allows communication of fluid pressure between the dampening chamber and the auxiliary braking arrangement to increase the effective braking of the auxiliary braking member. A throttle is disposed on the auxiliary braking member to allow communication of the fluid pressure in the dampening chamber to the work chamber into which the work piston is moving. A check valve is disposed between the pressurized work chamber and the dampening chamber to allow fluid pressure introduced to the pressurized work chamber to flow into the dampening chamber thereby pressurizing the dampening chamber as well.

Description

Die Erfindung betrifft einen druckmittelbetätigbaren Arbeitszylinder mit einer Einrichtung zum Dämpfen der Endabbremsung des Arbeitskolbens gemäss dem Oberbegriff des Patentanspruchs 1.The invention relates to a pressure-actuated working cylinder with a device for damping the end braking of the working piston according to the preamble of patent claim 1.

Ein derartiger doppeltwirkender Arbeitszylinder ist durch die DE-A- 3146 998 vorbekannt. Bei diesem Arbeitszylinder wird der Arbeitskolben in seinen beiden Endlagen dadurch gedämpft abgebremst, dass die Dämpfungskammer in der einen Endlage von einem kolbenartigen Vorsprung des einen Zylinderdeckels und einer entsprechenden Ausnehmung des Arbeitskolbens und in der anderen Endlage von einem kolbenartigen Vorsprung des Arbeitskolbens und einer entsprechenden Ausnehmung des anderen Zylinderdeckels gebildet wird. Dieser Arbeitszylinder ist somit nur in seinen beiden Endlagen und nicht in einer beliebigen Zwischenstellung gedämpft abbremsbar.Such a double-acting cylinder is previously known from DE-A-3146 998. In this working cylinder, the working piston is braked in its two end positions in such a way that the damping chamber is in one end position by a piston-like projection of one cylinder cover and a corresponding recess of the working piston and in the other end position by a piston-like projection of the working piston and a corresponding recess other cylinder cover is formed. This working cylinder can thus only be braked in its two end positions and not in any intermediate position.

Bei Arbeitszylindern, die als sogenannte Positionierungszylinder dienen, ist es jedoch erforderlich, den Arbeitskolben wahlweise in einer beliebigen Zwischenstellung anhalten zu können. Für die Positionierung eines Arbeitszylinders, d.h. das Anhalten in einer beliebig wählbaren Zwischenstellung des Arbeitskolbens, kann z.B. eine durch die US-A-4,073,217 vorbekannte Bremseinrichtung verwendet werden. Bei dieser Bremseinrichtung weist der Arbeitskolben auf seinem Mantel eine druckmittelbetätigbare, keilförmige Betätigungshilfe für radial bewegbare Bremselemente auf, die mit der Zylinderinnenwand in Reibschluss gebracht werden können. Insbesondere dann, wenn der Arbeitskolben und die von ihm bewegbaren bzw. abzubremsenden Teile eine grosse Masse aufweisen, ist ein schnelles Abbremsen ohne Dämpfungsmittel nur mit besonderen konstruktiven Massnahmen und erheblichem Aufwand an Steuermitteln zu erreichen. Bei derartigen Einrichtungen ist es dann insbesondere kaum möglich, die gewünschte, wahlweise bestimmbare Position mit der an sich erforderlichen Genauigkeit und Reproduzierbarkeit anzufahren.In the case of working cylinders which serve as so-called positioning cylinders, however, it is necessary to be able to stop the working piston optionally in any intermediate position. For the positioning of a working cylinder, i.e. stopping in an arbitrarily selectable intermediate position of the working piston can e.g. a braking device known from US-A-4,073,217 can be used. In this brake device, the working piston has on its jacket a pressure-medium-actuated, wedge-shaped actuation aid for radially movable brake elements, which can be brought into frictional engagement with the cylinder inner wall. Particularly when the working piston and the parts that can be moved or braked by it have a large mass, rapid braking without damping means can only be achieved with special design measures and considerable expenditure on control means. With such devices, it is then hardly possible to move to the desired, optionally determinable position with the accuracy and reproducibility required per se.

Der Erfindung liegt deshalb die Aufgabe zugrunde, einen druckmittelbetätigbaren Arbeitszylinder der eingangs genannten Art zu schaffen, der mit einfachen Mitteln eine genaue Positionierung in jeder möglichen Zwischenstellung des Arbeitskolbens bei gleichzeitig wirkender ausreichender Dämpfung ermöglicht.The invention is therefore based on the object of creating a pressure-actuated working cylinder of the type mentioned which, by simple means, enables precise positioning in any possible intermediate position of the working piston with adequate damping acting at the same time.

Diese Aufgabe wird durch die im Patentanspruch 1 angegebene Erfindung gelöst. Weiterbildungen und vorteilhafte Ausführungsbeispiele der Erfindung sind in den Unteransprüchen angegeben.This object is achieved by the invention specified in claim 1. Further developments and advantageous exemplary embodiments of the invention are specified in the subclaims.

Die Erfindung weist den Vorteil auf, dass für die exakte Positionierung zunächst nur der Zusatzkolben angehalten werden muss. Die Position des Zusatzkolbens ist auf einfache Weise mit den üblichen, bekannten Sensoren erfassbar. In einem Regelkreis odermiteiner Zielsteuerung wird dann der Zusatzkolben, der eine vergleichsweise geringe Masse aufweist, abgebremst und in der gewünschten Position festgesetzt. Es ist ohne weiteres möglich, den Zusatzkolben mit den erforderlichen Feststell-Bremskräften festzusetzen. Gegen den so festgesetzten Zusatzkolben, der dann sinngemäss eine feststehende Wand bildet, läuft dann der Arbeitskolben des Arbeitszylinders mit seiner Masse und der Masse der von ihm bewegten Teile auf. Diese Endabbremsung des Arbeitskolbens wird dann auf die an sich bekannte Weise gedämpft. Wenn dann der Arbeitskolben in seiner Endlage an dem Zusatzkolben zur Anlage kommt oder eine gegenüber dem Zusatzkolben festgelegte Endposition einnimmt, ist auch die Position des Arbeitskolbens exakt vorherbestimmbar. Bei der vorliegenden Erfindung werden also die beiden Funktionen «Positionieren» und «Endabbremsung» gewissermassen getrennt und jede für sich in der optimalen Weise realisiert.The invention has the advantage that only the additional piston has to be stopped for the exact positioning. The position of the additional piston can be detected in a simple manner with the usual, known sensors. The additional piston, which has a comparatively low mass, is then braked in a control loop or with a target control and fixed in the desired position. It is easily possible to fix the additional piston with the required parking brake forces. The working piston of the working cylinder then runs with its mass and the mass of the parts moved by it against the additional piston thus fixed, which then forms a fixed wall. This final braking of the working piston is then damped in a manner known per se. If the working piston then comes into contact with the additional piston in its end position or assumes an end position which is fixed with respect to the additional piston, the position of the working piston can also be exactly predetermined. In the present invention, the two functions “positioning” and “end deceleration” are separated to a certain extent, and each is implemented in the optimal manner.

Die Erfindung wird anhand eines Ausführungsbeispiels, das in der Zeichnung dargestellt ist, näher erläutert.The invention is explained in more detail using an exemplary embodiment which is illustrated in the drawing.

Die Zeichnung zeigt einen doppeltwirkenden Arbeitszylinder, der als Positionierzylinder verwendbar ist. In einem Zylinderrohr 48, das an seinen Enden mit einem mittels einer Dichtung 3 abgedichteten Deckel 60 und einem mittels einer Dichtung 33 abgedichteten Deckel 27 verschlossen ist, wird ein Arbeitskolben abgedichtet geführt. Dieser Arbeitskolben sitzt auf dem abgestuften Teilstück 15 einer Kolbenstange 30 und umfasst zwei Kolbenteile 43 und 45, zwischen denen eine Kolbenwand 14 angeordnet ist, die ihrerseits eine Kolbendichtung 13 trägt. Im folgenden wird der als Arbeitskolben dienende Kolben mit dem Bezugszeichen der Kolbenwand 14 benannt.The drawing shows a double-acting cylinder that can be used as a positioning cylinder. A working piston is guided in a sealed manner in a cylinder tube 48, which is closed at its ends by a cover 60 sealed by a seal 3 and a cover 27 sealed by a seal 33. This working piston sits on the stepped section 15 of a piston rod 30 and comprises two piston parts 43 and 45, between which a piston wall 14 is arranged, which in turn carries a piston seal 13. In the following, the piston serving as the working piston is named with the reference number of the piston wall 14.

Zur Befestigung des Kolbens 14 auf dem Teilstück 15 der Kolbenstange 30 ist eine auf ein entsprechendes Gewinde der Kolbenstange 30 aufschraubbare Mutter 57 vorgesehen, wobei zwischen dieser Mutter 57 und einem Absatz 22 der Kolbenstange 30 eine H ülse 55, das Kolbenteil 45, die Kolbenwand 14, das Kolbenteil 43 sowie eine weitere Hülse 20 eingespannt sind. Zwischen dem Kolbenteil 45 und der Hülse 55 einerseits und der Innenwand des Zylinderrohrs 48 andererseits ist ein Zusatzkolben 49 angeordnet, der die Hülse 55 und das Kolbenteil 45 ringförmig umgibt und einerseits mittels einer Dichtung 10 gegen die Innenwand des Zylinderrohrs 48 und andererseits mittels einer zwischen dem Kolbenteil 45 und der Hülse 55 angeordneten Dichtung 11 gegen den Kolben 14 abgedichtet ist. Der Zusatzkolben 49 liegt unter der Spannung einer Feder 46 an einem Absatz 61 der Hülse 55 an, so dass er gegen die Kraft der Feder 46 axial gegenüber dem Kolben 14 bewegbar ist. Die als Druckfeder ausgebildete Feder 46 stützt sich einerseits an der Kolbenwand 14 und andererseits an einem Absatz 47 des Zusatzkolbens 49 ab. Die Dichtung 11 ist als Rückschlagventil so ausgebildet, dass die zwischen dem Kolben 14 und dem Zusatzkolben 49 liegende Kammer 12, die als Dämpfungskammer dient, über das Rückschlagventil 11 mit dem Druck der zwischen dem Deckel 60 und dem Zusatzkolben 49 liegenden Arbeitsdruckkammer 5 beaufschlagbar ist.A nut 57, which can be screwed onto a corresponding thread of the piston rod 30, is provided for fastening the piston 14 to the section 15 of the piston rod 30, a sleeve 55, the piston part 45 and the piston wall 14 being between this nut 57 and a shoulder 22 of the piston rod 30 , the piston part 43 and a further sleeve 20 are clamped. Between the piston part 45 and the sleeve 55 on the one hand and the inner wall of the cylinder tube 48 on the other hand, an additional piston 49 is arranged, which surrounds the sleeve 55 and the piston part 45 in a ring and on the one hand by means of a seal 10 against the inner wall of the cylinder tube 48 and on the other hand by means of a between the Piston part 45 and the sleeve 55 arranged seal 11 is sealed against the piston 14. The additional piston 49 rests under the tension of a spring 46 on a shoulder 61 of the sleeve 55, so that it can be moved axially relative to the piston 14 against the force of the spring 46. The spring 46 designed as a compression spring is supported on the one hand on the piston wall 14 and on the other hand on a shoulder 47 of the additional piston 49. The seal 11 is designed as a check valve so that the chamber 12 between the piston 14 and the additional piston 49, which serves as a damping chamber, can be acted upon by the check valve 11 with the pressure of the working pressure chamber 5 lying between the cover 60 and the additional piston 49.

Entsprechend dem Zusatzkolben 49 ist auf der rechten Seite des Kolbens 14 ein weiterer Zusatzkolben 19 vorgesehen, der die Hülse 20 sowie das Kolbenteil 43 ringförmig umgibt und unter der Spannung einer Feder 42 an einem Vorsprung 21 der Hülse 20 anliegt. Die als Druckfeder ausgebildete Feder 42 ist zwischen der Kolbenwand 14 und einem Absatz 16 des Zusatzkolbens 19 angeordnet. Zur lnnenwand desZylinderrohrs48 hin ist der Zusatzkolben 19 mittels einer Dichtung 18 abgedichtet. Die Abdichtung gegenüber dem Kolbenteil 43 und damit gegenüber dem Kolben 14 erfolgt mittels einer Dichtung 17, die zwischen dem Kolbenteil 43 und der Hülse 20 angeordnet ist. Die Dichtung 17 dient als Rückschlagventil, über das die zwischen dem Kolben 14 und dem Zusatzkolben 19 liegende, als Dämpfungskammer vorgesehene Kammer 44 mit dem Druck der zwischen dem Deckel 27 und dem Zusatzkolben 19 liegenden Arbeitsdruckkammer 35 beaufschlagbarist. Man erkennt, dass der Zusatzkolben 19 entsprechend dem Zusatzkolben 49 axial gegenüber dem Kolben 14 bewegbar ist.Corresponding to the additional piston 49, a further additional piston 19 is provided on the right side of the piston 14, which surrounds the sleeve 20 and the piston part 43 in an annular manner and rests against a projection 21 of the sleeve 20 under the tension of a spring 42. The spring 42 designed as a compression spring is arranged between the piston wall 14 and a shoulder 16 of the additional piston 19. The additional piston 19 is sealed off from the inner wall of the cylinder tube 48 by means of a seal 18. The sealing against the piston part 43 and thus against the piston 14 takes place by means of a seal 17 which is arranged between the piston part 43 and the sleeve 20. The seal 17 serves as a check valve, via which the pressure between the working pressure chamber 35 located between the cover 27 and the additional piston 19 can be applied to the chamber 44 located between the piston 14 and the additional piston 19 and provided as a damping chamber. It can be seen that the additional piston 19 can be moved axially relative to the piston 14 in accordance with the additional piston 49.

Zur abgedichteten Führung der Kolbenstange 30 durch den Deckel 27 sind zwei ringförmige Dichtungen 34 und 29 vorgesehen. Die eigentliche Führung der Kolbenstange 30 im Deckel 27 wird von einem Führungslager 28 übernommen. Diese Lagerung der Kolbenstange 30 im Deckel 27 ist vergleichsweise reibungsarm und so ausgebildet, dass die Kolbenstange 30 gegenüber dem Deckel 27 praktisch kaum kippen kann.For the sealed guidance of the piston rod 30 through the cover 27, two annular seals 34 and 29 are provided. The actual guidance of the piston rod 30 in the cover 27 is carried out by a guide bearing 28. This mounting of the piston rod 30 in the cover 27 is comparatively low in friction and is designed such that the piston rod 30 can practically hardly tip over the cover 27.

Zum normalen Antrieb des soweit beschriebenen doppeltwirkenden Arbeitszylinders ist im Deckel 60 ein Druckluftanschluss 59 vorgesehen, der über eine Bohrung 58 mit der Arbeitsdruckkammer 5 verbunden ist. Bei einer Beaufschlagung des Druckluftanschlusses 59 mit Druckluft über eine nicht dargestellte Druckluftleitung werden die Arbeitsdruckkammer 5 und die Dämpfungskammer 12 mit Druckluft beaufschlagt, so dass der Kolben 14 nach rechts bewegt werden kann. Die Kraft der Feder 42 ist so gross bemessen, dass in dem beschriebenen Betriebszustand der Zusatzkolben 19 in der eingezeichneten Relativlage zum Kolben 14 ebenfalls nach rechts bewegt werden kann.For the normal drive of the double-acting working cylinder described so far, a compressed air connection 59 is provided in the cover 60, which is connected to the working pressure chamber 5 via a bore 58. When the compressed air connection 59 is pressurized with compressed air via a compressed air line (not shown), the working pressure chamber 5 and the damping chamber 12 are pressurized with compressed air, so that the piston 14 can be moved to the right. The force of the spring 42 is so large that in the described operating state the additional piston 19 can also be moved to the right in the position shown relative to the piston 14.

Zum Antrieb des Kolbens 14 nach links ist ein weiterer Druckluftanschluss 31 vorgesehen, der über eine Bohrung 32 mit der Arbeitsdruckkammer 35 verbunden ist. Bei einer Zuführung von Druckluft an den Druckluftanschluss 31 werden die Arbeitsdruckkammer 35 sowie die Dämpfungskammer 44 mit Druckluft gefüllt, so dass dann der Kolben 14 mit dem Zusatzkolben 19 nach links bewegt wird. Die Kraft der Feder 46 ist so bemessen, dass in dem zuletzt beschriebenen Betriebszustand der andere Zusatzkolben 49 in der eingezeichneten Relativlage zum Kolben 14 bleibt.To drive the piston 14 to the left, a further compressed air connection 31 is provided, which is connected to the working pressure chamber 35 via a bore 32. When compressed air is supplied to the compressed air connection 31, the working pressure chamber 35 and the damping chamber 44 are filled with compressed air, so that the piston 14 with the additional piston 19 is then moved to the left. The force of the spring 46 is dimensioned such that, in the operating state described last, the other additional piston 49 remains in the position shown relative to the piston 14.

Der Deckel 60 weist einen weiteren Druckluftanschluss 1 auf, der über eine Bohrung 2 mit einem in der Arbeitsdruckkammer 5 angeordneten Leitungsanschluss 4 verbunden ist. Der Leitungsanschluss 4 ist über eine flexible, wendelförmige Druckluftleitung 56 mit einem weiteren Leitungsanschluss 54 verbunden, der an dem Zusatzkolben 49 angeordnet ist. Der Leitungsanschluss 54 ist über eine Bohrung 53 des Zusatzkolbens 49 mit einer Bremsdruckkammer 52 des Zusatzkolbens 49 verbunden. Die Bremsdruckkammer 52 ist zur Innenwand des Zylinderrohrs 48 hin mit einer elastischen Membran 51 abgeschlossen, die sich bei Druckbeaufschlagung der Bremsdruckkammer 52 nach aussen nach Art eines Balges aufwölben kann. Zwischen der Membran 51 und der Innenwand des Zylinderrohrs 48 sind mehrere über den Umfang des Zusatzkolbens 49 verteilte, gegebenenfalls ein einziges Teil bildende Bremselemente 50 angeordnet, die radial nach aussen bewegbar sind, so dass sie mit der Innenwand des Zylinderrohrs 48 in Reibschluss bringbar sind.The cover 60 has a further compressed air connection 1, which is connected via a bore 2 to a line connection 4 arranged in the working pressure chamber 5. The line connection 4 is connected via a flexible, helical compressed air line 56 to a further line connection 54, which is arranged on the additional piston 49. The line connection 54 is connected via a bore 53 of the additional piston 49 to a brake pressure chamber 52 of the additional piston 49. The brake pressure chamber 52 is closed off from the inner wall of the cylinder tube 48 by an elastic membrane 51, which can bulge outward in the manner of a bellows when the brake pressure chamber 52 is pressurized. Arranged between the diaphragm 51 and the inner wall of the cylinder tube 48 are a plurality of brake elements 50 distributed over the circumference of the additional piston 49, possibly forming a single part, which can be moved radially outward so that they can be brought into frictional engagement with the inner wall of the cylinder tube 48.

Entsprechende Bremselemente 40 sind am Zusatzkolben 19 angeordnet, die zwischen der Innenwand des Zylinderrohrs 48 und einer elastischen Membran 38 liegen. Die Membran 38 schliesst eine Bremsdruckkammer 39 ab, die über eine Bohrung 37 und einen Leitungsanschluss 36 des Zusatzkolbens 19 sowie eine flexible, wendelförmige Druckluftleitung 23, einen in der Arbeitsdruckkammer 35 angeordneten Leitungsanschluss 24, eine Bohrung 25 im Deckel 27 mit einem entsprechenden Druckluftanschluss 26 verbunden ist. Auf diese Weise sind die Bremselemente 40 mittels Druckluftbeaufschlagung des Druckluftanschlusses 26 in Reibschluss mit der Innenwand des Zylinderrohrs 48 bringbar.Corresponding brake elements 40 are arranged on the additional piston 19, which lie between the inner wall of the cylinder tube 48 and an elastic membrane 38. The membrane 38 closes a brake pressure chamber 39, which connects a bore 25 in the cover 27 to a corresponding compressed air connection 26 via a bore 37 and a line connection 36 of the additional piston 19 as well as a flexible, helical compressed air line 23, a line connection 24 arranged in the working pressure chamber 35 is. In this way, the braking elements 40 can be brought into frictional engagement with the inner wall of the cylinder tube 48 by means of compressed air supply to the compressed air connection 26.

Die Bremsdruckkammern 39 und 52 sind jeweils über ein Rückschlagventil mit der zugeordneten Dämpfungskammer 44 bzw. 12 verbunden, wobei das Rückschlagventil jeweils zur Bremsdruckkammer hin öffnet. Zur Vereinfachung der Zeichnung ist dieses Rückschlagventil nur symbolisch als Ventil 41 bei dem Zusatzkolben 19 eingezeichnet. Ein entsprechendes Rückschlagventil ist im Zusatzkolben 49 angeordnet, wo es eine Verbindung zwischen der Dämpfungskammer 12 und der Bremsdruckkammer 52 bildet.The brake pressure chambers 39 and 52 are each connected to the associated damping chamber 44 or 12 via a check valve, the check valve opening towards the brake pressure chamber. To simplify the drawing, this check valve is shown only symbolically as valve 41 in the additional piston 19. A corresponding check valve is arranged in the additional piston 49, where it forms a connection between the damping chamber 12 and the brake pressure chamber 52.

Der Zusatzkolben 49 weist weitere Bohrungen 8 und 9 auf, zwischen denen eine mittels einer Schraube einstellbare Drossel 7 angeordnet ist. Über diese Drosseleinrichtung bzw. Drosselleitung 7,8,9 ist die Dämpfungskammer 12 mit einer die Hülse 55 umgebenden Ringkammer 6 verbunden, die ihrerseits mit der Arbeitsdruckkammer 5 verbunden ist. Man erkennt, dass das von der ringförmigen Lippendichtung 11 gebildete, zur Dämpfungskammer 12 hin öffnende Rückschlagventil von der Drosseleinrichtung 7, 8, 9 überbrückt ist. Eine entsprechende Drosseleinrichtung zur Überbrückung des von der ringförmigen Lippendichtung 15 gebildeten, zur Dämpfungskammer 44 hin öffnenden Rückschlagventils ist im Zusatzkolben 19 vorgesehen. Zur Vereinfachung der Zeichnung ist diese Drosseleinrichtung für den Zusatzkolben 19 jedoch nicht dargestellt.The additional piston 49 has further bores 8 and 9, between which a throttle 7 adjustable by means of a screw is arranged. Via this throttle device or throttle line 7, 8, 9, the damping chamber 12 is connected to an annular chamber 6 surrounding the sleeve 55, which in turn is connected to the working pressure chamber 5. It can be seen that the check valve formed by the annular lip seal 11 and opening towards the damping chamber 12 is bridged by the throttle device 7, 8, 9. A corresponding throttle device for bridging the check valve formed by the annular lip seal 15 and opening towards the damping chamber 44 is provided in the additional piston 19. To simplify the drawing, this throttle device for the additional piston 19 is not shown.

Der soweit beschriebene, in der Zeichnung in seiner Länge stark verringert dargestellte doppeltwirkende Arbeitszylinder arbeitet wie folgt: Es sei angenommen, dass der Kolben 14 aus der dargestellten Position heraus nach rechts bewegt werden soll, bis er eine vorgegebene Position erreicht hat. Die vorbestimmte Position soll dabei so erreicht bzw. angefahren werden, dass die Unterbrechung der Bewegung des Kolbens und damit die Unterbrechung der Bewegung der vom Kolben angetriebenen Massen gedämpft erfolgt.The double-acting working cylinder described so far and shown in the drawing with a greatly reduced length works as follows: It is assumed that the piston 14 is moved from the position shown to the right until it has reached a predetermined position. The predetermined position is to be reached or approached in such a way that the interruption of the movement of the piston and thus the interruption of the movement of the masses driven by the piston is damped.

Überein nicht dargestelltes Druckluft-Steuersystem mit entsprechenden Ventilen wird zunächst der Druckluftanschluss 59 mit Druckluft beaufschlagt. Dies führt dazu, dass die Arbeitsdruckkammer 5 und die Dämpfungskammer 12 ebenfalls mit Druckluft beaufschlagt werden. Sobald die auf diese Weise am Kolben 14 erzeugte Betätigungskraft in Richtung nach rechts die entgegengesetzt gerichteten Widerstandskräfte (Reibung, Last etc.) überwindet, wird der Kolben 14 nach rechts beschleunigt bewegt. Bei der Bewegung des Kolbens 14 nach rechts wird auf nicht dargestellte Weise überprüft, ob bzw. wann sich der Zusatzkolben 19 der vorbestimmten Position oder ob bzw. wann sich der Kolben 14 einer der vorbestimmten Position oder ob bzw. wann sich der Kolben 14 einer der vorbestimmten Position vorgelagerten entsprechenden Position nähert bzw. diese erreicht.A compressed air control system (not shown) with corresponding valves first applies compressed air to the compressed air connection 59. This means that the working pressure chamber 5 and the damping chamber 12 are also acted upon by compressed air. As soon as the actuating force generated in this way on the piston 14 in the right direction overcomes the oppositely directed resistance forces (friction, load, etc.), the piston 14 is moved accelerated to the right. When the piston 14 moves to the right, it is checked in a manner not shown whether or when the additional piston 19 is in the predetermined position or whether or when the piston 14 is in one of the predetermined positions or whether or when the piston 14 is in one of the approaching predetermined position upstream corresponding position or this reached.

Wenn beispielsweise (z.B. durch Abfragen und Erfassen der Stellung der Kolbenstange) festgestellt wird, dass der Zusatzkolben 19 die vorbestimmte Position erreicht hat, wird über das erwähnte Druckluft-Steuersystem der Druckluftanschluss 26 mit Druckluft beaufschlagt. Über den die Druckluftleitung 23 umfassenden Weg der Druckluft wird dann die Bremsdruckkammer 39 mit Druckluft beaufschlagt. Dies hat zur Folge, dass die Bremselemente 40 mit der Innenwand des Zylinderrohrs 48 in Reibschluss gebracht werden und derZusatzkolben 19 angehalten wird. Wegen der relativ geringen Masse des Zusatzkolbens 19 und der vergleichsweise kleinvolumigen Druckluft-Leitungen zum Ansteuern der Bremsdruckkammer 39 findet das Anhalten des Zusatzkolbens 19 sehr schnei) und sehr präzise statt. Der auf diese Weise festgesetzte Zusatzkolben 19 bildet dann auf der nicht vom Arbeitsdruck beaufschlagten Seite des Kolbens 14 gewissermassen eine feststehende Wand, die die Dampfungskammer 44 begrenzt.For example, if it is determined (e.g. by querying and detecting the position of the piston rod) that the additional piston 19 has reached the predetermined position, the compressed air connection 26 is acted upon by compressed air via the aforementioned compressed air control system. The brake pressure chamber 39 is then pressurized with compressed air via the path of the compressed air comprising the compressed air line 23. As a result, the braking elements 40 are brought into frictional engagement with the inner wall of the cylinder tube 48 and the additional piston 19 is stopped. Because of the relatively small mass of the additional piston 19 and the comparatively small-volume compressed air lines for actuating the brake pressure chamber 39, the additional piston 19 is stopped very quickly and very precisely. The additional piston 19 fixed in this way then forms, to a certain extent, a fixed wall on the side of the piston 14 not acted upon by the working pressure, which delimits the steaming chamber 44.

Gleichzeitig mit dem Anhalten und Festsetzen des Zusatzkolbens 19 kann die Beaufschlagung der Arbeitsdruckkammer 5 mit Druckluft unterbrochen werden. Der Kolben 14 wird - schon aufgrund seiner und der von ihm bewegten Massen - dann weiter nach rechts laufen.Simultaneously with the stopping and fixing of the additional piston 19, the application of compressed air to the working pressure chamber 5 can be interrupted. The piston 14 will - due to its and the masses moved by it - then continue to run to the right.

Dabei wird dann das Volumen der Dämpfungskammer 44 verkleinert und der Druck in dieser Dämpfungskammer 44 entsprechend erhöht, da die Lippendichtung 17 eine Entlüftung der Dämpfungskammer 44 verhindert. Eine Druckentlastung bzw. Entlüftung der Dämpfungskammer 44 erfolgt nur über die nicht dargestellte Drosseleinrichtung (entsprechend der Drosseleinrichtung 7, 8, 9 des Zusatzkolbens 49) und das Rückschlagventil 41. Aufgrund der dynamischen Vorgänge wird somit die Dämpfungskammer 44 gedrosselt entlüftet. Dies bedeutet, dass die Bewegung des Kolbens 14 gedämpft abgebremst wird. Bei einer der üblichen Belastung und Bewegungsgeschwindigkeit des Kolbens 14 angepassten entsprechenden Bemessung der Drosseleinrichtung wird der Kolben 14 schliesslich zur Anlage am Zusatzkolben 19 kommen und somit genau die vorbestimmte Position gedämpft erreichen.The volume of the damping chamber 44 is then reduced and the pressure in this damping chamber 44 is increased accordingly, since the lip seal 17 prevents venting of the damping chamber 44. A pressure relief or venting of the damping chamber 44 takes place only via the throttle device (not shown) (corresponding to the throttle device 7, 8, 9 of the additional piston 49) and the check valve 41. The damping chamber 44 is thus throttled vented due to the dynamic processes. This means that the movement of the piston 14 is braked in a damped manner. With a corresponding dimensioning of the throttle device adapted to the usual load and speed of movement of the piston 14, the piston 14 will finally come to rest on the additional piston 19 and thus reach the predetermined position in a damped manner.

Der beim Abbremsen des Kolbens 14 entstehende Druck in der Dämpfungskammer 44, der über das Rückschlagventil 41 auch in die Bremsdruckkammer 39 geleitet wird, erhöht in der Bremsdruckkammer 39 den dort wirkenden Bremsdruck. Auf diese Weise wird die Bremskraft der Bremselemente 40 genau in dem Augenblick erhöht, in dem die Bremskraft am grössten sein muss. Da sich schon bei einer relativ geringen axialen Erstrekkung der Bremselemente eine relativ grosse Fläche für den Reibschluss zwischen der Innenwand des Zylinderrohrs 48 und den Bremselementen 40 ergibt, wird eine sehr grosse Bremskraft am Zusatzkolben 19 erreicht. Diese Bremskraft kann ohne weiteres so gross werden, dass der Kolben 14 auch bei anhaltender Beaufschlagung der Arbeitsdruckkammer 5 mit Druckluft in der vorbestimmten Position gehalten werden kann. Eine entsprechende Arbeitsweise ergibt sich bei einer gesteuerten Bewegung des Kolbens 14 von rechts nach links. In diesem Fall bildet dann der Zusatzkolben 49 die feststehende Wand, an die sich der Kolben 14 beim Erreichen der vorbestimmten Position gedämpft anlegt.The pressure which arises in the damping chamber 44 when the piston 14 is braked and which is also passed into the brake pressure chamber 39 via the check valve 41 increases the brake pressure acting there in the brake pressure chamber 39. In this way, the braking force of the braking elements 40 is increased exactly at the moment when the braking force must be the greatest. Since there is a relatively large area for the frictional connection between the inner wall of the cylinder tube 48 and the brake elements 40 even with a relatively small axial extension of the brake elements, a very large braking force is achieved on the additional piston 19. This braking force can easily become so great that the piston 14 can be held in the predetermined position even when the working pressure chamber 5 is continuously pressurized with compressed air. A corresponding mode of operation results from a controlled movement of the piston 14 from right to left. In this case, the additional piston 49 then forms the fixed wall, against which the piston 14 abuts when the predetermined position is reached.

Statt der Membranen 38 und 51 zum Betätigen der Bremselemente40 und 50 können auchdruckmittelbetätigte Kolben verwendet werden. Es ist auch möglich, die Dämpfungseinrichtung für den Kolben 14 anders als in der beschriebenen Weise auszubilden. So istesz.B. vorteilhaft möglich, dass die Dämpfungskammer von einem kolbenartigen Vorsprung des Arbeitskolbens oder des Zusatzkolbens und einer Ausnehmung des Zusatzkolbens oder des Arbeitskolbens gebildet ist, wobei die Ausnehmung zur abgedichteten Aufnahme des kolbenartigen Vorsprungs dient. Die gedrosselte Entlüftung der Dämpfungskammer erfolgt dabei in ähnlicher Weise wie bei dem beschriebenen Ausführungsbeispiel. Die Dämpfungskammer kann auch statt direkt vom Arbeitskolben von einem auf der entsprechenden Seite des Arbeitskolbens angeordneten und kraftschlüssig mit dem Arbeitskolben verbundenen Druckstück gebildet sein.Instead of the membranes 38 and 51 for actuating the brake elements 40 and 50, pressure-actuated pistons can also be used. It is also possible to design the damping device for the piston 14 differently than in the manner described. For example, advantageously possible that the damping chamber is formed by a piston-like projection of the working piston or the additional piston and a recess of the additional piston or the working piston, the recess serving for the sealed reception of the piston-like projection. The throttled venting of the damping chamber takes place in a manner similar to that in the exemplary embodiment described. The damping chamber can also be formed instead of directly from the working piston by a pressure piece arranged on the corresponding side of the working piston and non-positively connected to the working piston.

Claims (14)

1. Pressure medium-operable working cylinder having a device for cushioning the stopping at the end of the stroke of the working piston (14), which working cylinder has the following features:
a) there is provided at least one cushioning chamber (12,44) which is formed by a wall that is fixed relative to the working piston (14) and by at least one portion of the side of the working piston (14) that is not acted upon by working pressure or by a thrust member that is arranged on that side of the working piston (14) and is connected non- positively to the working piston (14);
b) there is provided a throttle device (7), via which the cushioning chamber (12, 44) can be vented; characterised by the following features:
c) on the side of the working piston (14) that is not acted upon by working pressure there is arranged an auxiliary piston (19, 49) that can be displaced axially and relative to the working piston (14);
d) there is provided a braking device (40, 50) for fixing the auxiliary piston (19, 49) relative to the cylinder (48);
e) the auxiliary piston (19, 49) is so designed that, when not in the fixed condition, it can be moved with the working piston (14) at a predetermined distance therefrom and, when in the fixed condition, it forms the fixed wall.
2. Working cylinder according to claim 1, characterised in thatthe auxiliary piston (19, 49) is displaceably arranged on an axially extending projection of the working piston (14).
3. Working cylinder according to claim 1 or 2 that is double-acting, characterised in that an auxiliary piston (19, 49) is arranged on each side of the double-acting working piston (14), which auxiliary pistons (19, 49) surround in an annular manner the piston rod (30) and a projection of the working piston (14), respectively.
4. Working cylinder according to at least one of the preceding claims, characterised in that the braking device (38,51) can be operated by pressure medium.
5. Working cylinder according to claim 4, characterised in that a flexible pressure-medium line (23,56) arranged helically in the cylinder (48) is provided for supplying pressure medium for the braking device (38, 51).
6. Working cylinder according to at least one of the preceding claims, characterised in that the braking device comprises one or more brake members (40, 50) which are arranged on the auxiliary piston (19,49) in such a manner that they can be moved radially and which can be brought into frictional contact with the inner wall of the cylinder (48).
7. Working cylinder according to claim 6, characterised in that a pressure medium-operable working piston (38, 51) is provided for the radial movement of a brake member (40, 50), which working piston (38, 51) is arranged in or on the auxiliary piston (19, 49).
8. Working cylinder according to claim 6 or 7, characterised in that a pressure-medium chamber (39, 52) that can be enlarged in the manner of a bellows is provided for actuating the brake members (40, 50).
9. Working cylinder according to at least one of the preceding claims, characterised in that the cushioning chamber is formed by a piston-like projection on the working piston or on the auxiliary piston and a recess in the auxiliary piston or in the working piston, the recess serving to receive the piston-like projection in a sealed manner.
10. Working cylinder according to at least one of the preceding claims, characterised in that the cushioning chamber (12, 44) is formed by the working piston (14), a centrally located axial projection (43, 45) on the working piston (14) or the piston rod (30) of a double-acting working cylinder, the inner wall of the cylinder and the auxiliary piston (19, 49) that is in the form of an annular piston and is guided in a sealed manner with respect to the inner wall of the cylinder and the centrally located projection.
11. Working cylinder according to claim 10, characterised by the following features:
a) a stop (21, 61) for the auxiliary piston (19,
49) is provided on the centrally located projection or on the piston rod;
b) there is provided a spring (42, 46) that acts upon the auxiliary piston (19, 49) with a spring force away from the working piston (14) in the direction towards the stop (21, 62).
12. Working cylinder according to claim 10 or 11, characterised in that in a pressure-medium line through which pressure medium can be admitted to a pressure chamber (12, 44) located between the working piston and the auxiliary piston there is provided a non-return valve (17, 11) that opens towards the pressure chamber (12, 44).
13. Working cylinder according to claim 12, characterised in that the non-return valve is formed by a seal (17,11) that seals the auxiliary piston (19, 49) with respect to the piston rod (30).
14. Working cylinder according to at least one of the preceding claims, characterised in that the throttle device (7) is arranged in a throttle line (8, 9) via which the cushioning chamber (12, 44) is connected to one of the cylinder chambers (5, 35) formed by the working piston (14).
EP84111136A 1983-10-26 1984-09-19 Fluid pressure actuator having a piston cushioning device in final positions Expired EP0141215B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84111136T ATE25279T1 (en) 1983-10-26 1984-09-19 PRESSURE-ACTIVATED WORKING CYLINDER WITH A DEVICE FOR DAMPING THE FINAL BRAKING OF THE WORKING PISTON.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19833338781 DE3338781A1 (en) 1983-10-26 1983-10-26 PRESSURE-OPERATED WORKING CYLINDER WITH A DEVICE FOR DAMPING THE FINAL BRAKE OF THE WORKING PISTON
DE3338781 1983-10-26

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EP0141215A1 EP0141215A1 (en) 1985-05-15
EP0141215B1 true EP0141215B1 (en) 1987-01-28

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EP (1) EP0141215B1 (en)
AT (1) ATE25279T1 (en)
DE (2) DE3338781A1 (en)

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Also Published As

Publication number Publication date
DE3462280D1 (en) 1987-03-05
ATE25279T1 (en) 1987-02-15
EP0141215A1 (en) 1985-05-15
DE3338781A1 (en) 1985-05-09
US4633758A (en) 1987-01-06

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