EP0446694B1 - Locking device for pneumatic cylinders - Google Patents

Locking device for pneumatic cylinders Download PDF

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Publication number
EP0446694B1
EP0446694B1 EP91102752A EP91102752A EP0446694B1 EP 0446694 B1 EP0446694 B1 EP 0446694B1 EP 91102752 A EP91102752 A EP 91102752A EP 91102752 A EP91102752 A EP 91102752A EP 0446694 B1 EP0446694 B1 EP 0446694B1
Authority
EP
European Patent Office
Prior art keywords
locking
piston
arms
control means
thrust
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 - Lifetime
Application number
EP91102752A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0446694A1 (en
Inventor
Luciano Migliori
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.)
Univer SpA
Original Assignee
Univer SpA
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 Univer SpA filed Critical Univer SpA
Publication of EP0446694A1 publication Critical patent/EP0446694A1/en
Application granted granted Critical
Publication of EP0446694B1 publication Critical patent/EP0446694B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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

Definitions

  • the present invention relates to a pneumatically actuated locking device for stopping the reciprocation movement in rod and rodless types of pneumatic cylinders, by means of which it is possible to exert a considerable instantaneous force so as to lock any moving member connected to the cylinder.
  • Locking devices for pneumatic cylinders also known which make use of an annular locking element elastically deformed by a set of levers operated by axially movable cam members, to engage a rod.
  • Such locking devices must operate each time an anomalous working condition occurs in the pressurized air supply network, in order to block the movement of the movable portion of the cylinder, or of mechanical parts connected thereto, or in order to perform given functions during an operative cycle.
  • the locking devices of the type referred above have only a limited number of applications owing to their excessively large overall dimensions, and a limited degree of operational reliability; furthermore they are unable to operate in both moving directions of the cylinder and therefore tend to exert excessively high specific locking forces, which compromise the sealing and the proper operation of the cylinder.
  • a locking device which constitutes the basis for the pre-caracterizing part of the claim 1.
  • a locking member firmly rests against a bottom surface; the locking member comprises locking arms having conical surfaces which are extending towards said bottom surface. Therefore no self-centering and no amplifying actions of locking forces are made possible in said known device.
  • a scope of present invention is to provide a locking device for pneumatic cylinders in order to solve the problems arising from previously known locking devices, in particular to reduce the overall dimensions, increase the locking forces while maintaining the specific pressures at sufficiently low levels, and at the same time allowing application of the device to any pneumatic cylinder, with or without a rod, while maintaining a high degree of efficiency in both operative directions.
  • Figure 1 shows a pneumatic cylinder comprising a cylinder barrel 10, or first cylinder portion, in which a reciprocable piston member 11 slide; the piston 11 define a second cylinder portion connected to a rod 12 which protrudes in a sealed manner through an head 13 of the cylinder.
  • 14 denotes a locking, device for stopping and/or retaining the piston 11, as well as an operative member (not shown) connected to the reciprocable portion of the cylinder, in a fixed position according to the requirements; in the example shown, the locking device 14 is directly connected to the end part 13 of the cylinder. It is obvious, however, that the locking device 14 may be differently arranged and provided also in rodless cylinders, and the like.
  • the locking device 14 comprises a housing or hollow body 15 defining a chamber 16 open at both ends, through which the rod 12 of the cylinder axially slides.
  • a pneumatically actuated locking means comprising an U-shaped locking member 17 having locking arms 17a, 17b peripherally arranged to engage and disengage the rod 12 so as to block its movement instantly.
  • the locking member 17 is positioned between pneumatically actuated control means comprising a thrust piston member 21 and a reaction member 20 provided with centering surfaces and thrust amplifying surfaces means.
  • the U-shaped locking member 17 comprises lateral arms 17a and 17b and an intermediate bottom portion 17c defining an elastically yieldable connecting member for said arms 17a, 17b.
  • said arms 17a, 17b and said bottom portion 17c of the locking member 17 define a circular inner surface 18 which slightly fits against most of the circumferential periphery of the rod 12; the bottom portion 17c of the locking member 17 rests against opposing slanted surfaces 19 of the reaction member 20 which are diverging towards the rod 12 thus maintaining a self-centring arrangement of the locking member 17.
  • the bottom portion 17c of the locking member 17 has a reduced thickness so as to allow elastic yielding of the locking arms 17a, 17b against the rod 12, under the action of the upper thrust member 21 and reaction member 20; therefore, the arms 17a and 17b of the locking member extend in the direction of and towards the thrust member 21, terminating at their ends with opposite slanted surfaces which fit against corresponding slanted surfaces 22 of the above mentioned thrust member 21, to increase the locking forces of the locking member 17 acting on the rod 12 by a sliding forward movement of the thrust member 21.
  • the thrust member 21 is pneumatically operated by a piston 23 reciprocable in an annular chamber 24 inside the body 15.
  • the side of the chamber 24 which is opposite to the thrust member 21 is connected by a duct 25 to an inlet 26 for the pressurized air.
  • a biasing means such as spring 21' acting in the same direction of the pressurized air, may be provided behind the piston 23 of the thrust member 21, as shown in Figure 2, to force the thrust member 21 forward to lock the rod 12 and/or to maintain said rod 12 locked also in absence of pressurized air.
  • Disengagement of the locking member 17 from the rod 12 may be performed, for example, as shown in Figure 2, by providing pneumatically actuated disengaging means; said means comprises a second piston 27 on the side of the reaction member 20 which is opposite to thrust member 21.
  • the piston 27 is reciprocable inside a chamber 28 which may be supplied with a fluid under pressure, for example pressurized air, via a duct 29 and an opening 30 on the side of the chamber 28 which is opposite to the reaction member 20, as shown in figure 2.
  • the piston 27 acts on the thrust member 21, upon release of the pneumatic force, for example by means of pins 31, or any suitable equivalent means, which pins freely pass and slide through holes 32 in the reaction member 20, so as to extend parallelly to the arms 17a, 17b of the locking member 17, towards and against the abovementioned thrust member 21.
  • a biasing spring 33 may be optionally provided between the piston 27 and an end wall portion of the housing 15 so as to push the piston 27 and the thrust member 21 in the disengaged condition of the locking member 17.
  • the operation mode of the locking device is as follows: during normal operation of the cylinder 10, the pressurized air is fed inside the chamber 28 for the piston 27 to deactivate the locking device; in this condition the piston 27 acts, via the pins 31, on the thrust member 21 so as to cause it to slightly move backwards by an amount sufficient to allow disengagement of the jaw 17 and sliding of the rod 12 of the cylinder.
  • the U-shaped locking member 17 is able to extend axially or parallelly to the rod by an amount sufficient to allow high locking forces, while maintaining low specific pressures so as not to harm or cause any damage to the rod itself.
  • the spring 27, which acts on the thrust member 21 in opposition to the spring 33, is able to exert a greater force such that the device is operationally in a condition where the rod 12 is locked in the absence of pressurized fluid; however, it is obvious that the arrangement could be reversed, with a device operating under normally disengaged conditions.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Jigs For Machine Tools (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Actuator (AREA)
  • Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
EP91102752A 1990-03-14 1991-02-25 Locking device for pneumatic cylinders Expired - Lifetime EP0446694B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT1967190 1990-03-14
IT19671A IT1239695B (it) 1990-03-14 1990-03-14 Dispositivo di ritenuta per cilindri pneumatici

Publications (2)

Publication Number Publication Date
EP0446694A1 EP0446694A1 (en) 1991-09-18
EP0446694B1 true EP0446694B1 (en) 1994-11-09

Family

ID=11160270

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91102752A Expired - Lifetime EP0446694B1 (en) 1990-03-14 1991-02-25 Locking device for pneumatic cylinders

Country Status (5)

Country Link
EP (1) EP0446694B1 (it)
AT (1) ATE114022T1 (it)
DE (1) DE69105009T2 (it)
ES (1) ES2064784T3 (it)
IT (1) IT1239695B (it)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19543471C1 (de) * 1995-11-22 1997-01-09 Festo Kg Klemmeinheit
EP1144153B1 (de) * 1999-06-07 2004-11-10 Frenotech Establishment Feststelleinrichtung zum klemmen einer welle oder stange
DE50113523D1 (de) * 2000-07-07 2008-03-13 Frenotech Establishment Feststelleinrichtung
DE202018005634U1 (de) * 2018-12-09 2020-03-11 Herbert Höfler Feststelleinrichtung

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4791855A (en) * 1985-03-11 1988-12-20 Pubot Giken Co., Ltd. Cylinder locking device
JPS61233209A (ja) * 1985-04-09 1986-10-17 Akio Matsui シリンダ停止装置
DE3810388A1 (de) * 1988-03-26 1989-10-05 Kontec Gmbh Vorrichtung zum festspannen eines linear bewegbaren, langgestreckten bauteils

Also Published As

Publication number Publication date
ES2064784T3 (es) 1995-02-01
DE69105009T2 (de) 1995-04-20
IT9019671A1 (it) 1991-09-14
IT1239695B (it) 1993-11-15
IT9019671A0 (it) 1990-03-14
EP0446694A1 (en) 1991-09-18
ATE114022T1 (de) 1994-11-15
DE69105009D1 (de) 1994-12-15

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