EP0648941A1 - Pneumatisches Stellorgan mit einstellbarer Endlagen- und Dämpfungseinrichtung - Google Patents

Pneumatisches Stellorgan mit einstellbarer Endlagen- und Dämpfungseinrichtung Download PDF

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Publication number
EP0648941A1
EP0648941A1 EP94116318A EP94116318A EP0648941A1 EP 0648941 A1 EP0648941 A1 EP 0648941A1 EP 94116318 A EP94116318 A EP 94116318A EP 94116318 A EP94116318 A EP 94116318A EP 0648941 A1 EP0648941 A1 EP 0648941A1
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EP
European Patent Office
Prior art keywords
sleeve member
piston
stop
damping
movable sleeve
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.)
Ceased
Application number
EP94116318A
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English (en)
French (fr)
Inventor
S.P.A. Univer
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
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Filing date
Publication date
Application filed by Univer SpA filed Critical Univer SpA
Publication of EP0648941A1 publication Critical patent/EP0648941A1/de
Ceased legal-status Critical Current

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    • 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
    • F15B15/24—Other details, e.g. assembly with regulating devices for restricting the stroke
    • 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
    • F15B15/223—Other details, e.g. assembly with regulating devices for accelerating or decelerating the stroke having a piston with a piston extension or piston recess which completely seals the main fluid outlet as the piston approaches its end position

Definitions

  • the present invention relates to improvements to pneumatic linear actuators, and concerns more particularly a pneumatic cylinder provided with pneumatic damping means and a mechanical stop whose position can be axially adjusted in order to modify the effective working stroke of the actuator itself.
  • Pneumatic dampers are widely used in linear actuators to absorb most of the kinetic energy of the load by decelerating the piston at the end of the working stroke.
  • these pneumatic dampers are provided on the closure heads of the cylinder and are based on the principle of dissipation of energy by releasing a predetermined quantity of pressurised air through a throttling valve at the end of each stroke of the piston.
  • the dampers of this type generally have a fixed position, which cannot be adjusted or modified, so that they would be totally ineffective in the case wherein it is necessary to change the mechanical stop which limits the effective working stroke of the piston. With traditional pneumatic dampers it is therefore impossible to regulate their position, especially on the side relating to the piston rod, nor are suitable solutions to this problem known.
  • the object of the present invention is to provide a linear actuator provided with an integrated pneumatic damping and stop device as mentioned above which can be applied to cylinders both with and without rod, and which allows simultaneous regulation both of the mechanical stop and of the pneumatic damping device.
  • a further object of the present invention is to provide a pneumatic linear actuator, as related above, provided with an adjustable pneumatic damping means, which is able to maintain its damping efficiency substantially unchanged, independently of the position assumed, in this way guaranteeing a deceleration effect of the piston which remains unchanged and reliable, thus allowing high accuracy of stopping and positioning of the load moved by the actuator.
  • a further object of the present invention is to provide a pneumatic linear actuator of the kind mentioned above, provided with an adjustable pneumatic damping device which can be housed inside the same actuator, without substantially increasing its overall dimensions, and which can be applied in cylinders or actuators either with or without rod, maintaining an arrangement coaxial to the reciprocable piston.
  • a pneumatic linear actuator comprising a telescopically extendable fluid actuated damper and mechanical stop means, according to the features of the claim 1.
  • the pneumatic actuator substantially comprises a cylinder body 10 defining a piston chamber 10a closed by two end heads 11 and 12. Each head is provided with a hole 13, 14 for feeding and discharging compressed air, as well as a throttle valve 15, 16 forming part of a pneumatic shock absorber device described hereinbelow.
  • a reciprocating piston 17 Inside the cylinder 10 is a reciprocating piston 17 provided with a rod 18 which extends externally along a hole 19, through a seal 20 in the corresponding head 11 of the actuator.
  • the piston 17, in the case shown, has at each end a cylindrical shank 21, only one shown in Figure 2, having a diameter greater than the rod 18 for actuating at the end of the stroke a respective pneumatic damping device which, in a manner in itself known, allows the kinetic energy accumulated by the piston to be dissipated, thus decelerating the same by discharging from the chamber 10a the pressurized air remaining in the final portion of the piston stroke via one or the other of the throttling valves 15 or 16, provided in a respective end head 11, 12 of the actuator.
  • the pneumatic damping and stop device substantially comprises a telescopically extendable flow-path unit 22, having a flanged end seated in the head 11 to project, tightly, inside the cylinder body 10.
  • the telescopic unit 22 has an axially extending bore 34 having a diameter greater than the rod 18 to define an annular main duct for feeding and discharging compressed air respectively, leading on one side into the chamber 10a of the cylinder body 10 and on the other into the feed/discharge port 13.
  • Said telescopic flow-path unit 22 of the damping and stop device at its inner end has a first seal element in the form of an annular seal 35 coaxially arranged to the main duct 34 which cooperates with a second seal element carried by the piston 17, for example in the form of a cylindrical shank 36 having a diameter greater than the rod 18 to penetrate the annular seal 35 to close the main duct 34, as shown.
  • the cylindrical extension of the head 11 forming the pneumatic damping and stop device 22, comprises moreover a branched flow-path to connect the chamber 10a of the cylinder to the main duct 34, via an adjustable throttling valve 15 in the head 11.
  • the branched path is formed between two tubular members coaxially arranged and sliding one to the other to allow the telescopic lengthening and shortening of the pneumatic damping and stop unit 22, maintaining the connection of the chamber 10a with the throttling valve 15, without substantially varying the required volume of pressurized air which has to be vented by valve 15 for damping and deceleration of the piston 17.
  • the unit 22 comprises a first fixed sleeve 21 which extends axially inside the cylinder body 10, starting from the end closure head 11.
  • a second tubular element is provided in the form of a double walled sleeve sliding longitudinally to the first one and guided by the internal surface of the cylinder body 10.
  • the double sleeve comprises a first outer wall 23 which surrounds the fixed sleeve 21, and a second inner wall 24 which surrounds the fixed sleeve 21 and which defines the main duct 34 for feeding and discharging pressurized air.
  • the inner wall 24 of the double sleeve is appropriately connected to the outer wall 23 at their remote end, while the opposite surface of the two walls 23 and 24 facing corresponding surface of sleeve 21 have different diameters and are spaced apart in order to form an annular groove having a closed bottom end wherein the fixed sleeve 21 extends.
  • the opposite cylindrical surfaces of the fixed sleeve 21 and of the inner wall 24 of the sliding sleeve have screw connection means in the form of threading 25 to allow a telescopic sliding movement of the sleeves 21, 24 as explained hereinbelow.
  • the external cylindrical surface of the fixed sleeve 21 and the internal cylindrical surface of the outer wall 23 of the sliding sleeve have slightly differing diameters or are radially spaced apart such as to form a narrow annular gap 26 which extends axially for a length equal to or greater than the adjustable stroke of the pneumatic damping and stop device 22.
  • the annular gap 26 which is formed between the two sleeves, at one end is connected to a longitudinal bore 27 in the outer tubular wall 23 of the sliding sleeve, which hole 27 at the other side opens towards the chamber 10a of the cylinder body 10 via an annular groove 28 and a slot or slots 29 formed between a lip seal 35 and a respective seat in an extension 22' with a small diameter.
  • This extension 22' also defines a mechanical stop surface for the piston 17.
  • Seals 30 and 31 at the two ends of the outer tubular wall 23 of the sliding sleeve provide tightness in respect of the cylinder body 10 and the fixed sleeve 21 respectively. In this way tightness is ensured whatever axial position is adopted by the wall 23 of the sliding sleeve.
  • the annular gap 26 on the side opposite the previous one additionally is connected to a second bore 32 formed in the fixed sleeve 21.
  • the bore 32 extends in the head 11 opening at the throttling or needle valve 15.
  • a third seal 33 is finally disposed between the internal end of the fixed sleeve 21 and the internal surface of the tubular wall 23 of the sliding sleeve.
  • a lip seal 35 is provided, designed to form a seal with a shank 36 coaxially arranged to the rod 18 of the piston.
  • reference 37 in Figures 2 and 4 denotes radial holes provided in angularly spaced positions on the outer tubular wall 23 of the sliding sleeve, made accessible at a wide opening 38 in a wall of the cylinder body 10 to vary the length of the damping and stop device by means of a simple rotation of the same sliding sleeve in respect to the fixed sleeve.
  • the axial length of the opening 38 in the wall of the cylinder body 10 must be greater than the adjusting stroke of the abovementioned damping and stop device.
  • the pneumatic damping and stop device has been advantageously provided on the side of the rod 18 of the cylinder, nevertheless the same device may be provided on the opposite side of the cylinder, at the rear head 12, forming in the latter a special seating for inserting the shaped end of the fixed sleeve 21.
  • the entire device can be provided in the form of a cartridge placed fully inside the cylinder body 10, perfectly coaxial to the piston, eliminating any outward bulk.
  • a pneumatic actuator is provided with an adjustable stroke and pneumatic damping device allowing a mechanical stop of the piston which can be adjusted according to the requirements, maintaining a simple and substantially strong structure of the entire actuator.
  • Figures 1 to 4 show an embodiment of the damping and stop device which is particularly suitable for application to an actuator having a rod.
  • Figure 5 of the accompanying drawings shows a second embodiment of the telescopic damping and stop device which has been especially designed for a rodless actuator, and which, like the previous one, allows telescopic regulation of position and the use of a flow path duly set for expulsion of the air through the throttle valve, which maintains the necessary volume of air substantially unchanged.
  • Figure 5 partially represents a rodless cylinder in itself known.
  • a rodless cylinder comprises a tubular body 40 inside of which a piston 41 moves.
  • the piston 41 is connected to an external member (not shown) through a longitudinal slot 42 on one side of the body 40, normally closed by a flexible band schematically denoted by 43.
  • the piston 41 on each side, has a hole 44 which is penetrated by a tubular shank 45 connected to a port 46 for feeding and discharging pressurized air provided in the head 47, via an axial duct 48 in a tubular member 49 which in this specific case define a threaded shaft rotatably supported by the head 47 and which can be actuated by a control knob 50.
  • the tubular shank 45 co-operates with a seal 51 placed in a seating at one end of piston 41 coaxially to the hole 44 to close communication of the chamber 52 towards the duct 48 and the port 46 for feeding/discharging air at the end of the piston stroke as shown in Figure 5.
  • the tubular shank 45 is tightly attached to the internal end of a sleeve 53 which in turn telescopically and tightly slides in the chamber 52 of the cylinder body 40.
  • the sleeve 53 is provided with internal threading 54 engaging with the threaded shaft 49 to move the sleeve 53 forwards and backwards by simply rotating manually the knob 50.
  • the sleeve 53 has a portion 53a, with a small diameter, telescopically guided by a cylindrical sleeve portion 47a of the head 47, which extends inside the cylinder body 40.
  • the sleeve 53 is prevented from rotating by a pin 55 which projects from the head 47 and which sliding penetrates, a hole 56 of the sleeve 53.
  • the pneumatic damping device described here also comprises a telescopically extending branched path for discharging air through a throttle valve 57.
  • the branched path which, like the previous case, can be lengthen and shorten telescopically without producing significant variations in the volume of air to be ejected during damping, in this specific case consists of a first duct in the form of a calibrated tube 58 longitudinally extending inside the cylinder body 40 and attached on the internal side of the head 47.
  • the duct 58 on one side leads to the valve 57 through appropriate passage ports, while on the other side it leads to a hole 59 which extends in the sleeve 53 parallel to its sliding axis, and wherein the same tube 58 can freely and telescopically slide.
  • the hole 59 opens into the chamber 52 of the cylinder body near an annular element 60 at the internal end of the sleeve 53 designed to form a stop for a ring nut 61 at the opposite end of the piston 41.
  • Suitable seals provide the necessary tightness between the sleeve 53 and the cylinder body 40, and between the latter and the head 47 respectively, as well as between the sleeve 53 and the tube 58.
  • the invention consists of a special pneumatic damping and stop device whose position can be adjusted telescopically, suitable both for cylinders with a rod, and for rodless cylinders by means of which the numerous advantages and improved features of the invention are obtained, maintaining substantially unchanged the capacity to pneumatically dampen the kinetic energy accumulated by the piston 41 and by the load connected thereto, independently of the position adopted by the same device.
EP94116318A 1993-10-18 1994-10-17 Pneumatisches Stellorgan mit einstellbarer Endlagen- und Dämpfungseinrichtung Ceased EP0648941A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITMI932209 1993-10-18
ITMI932209A IT1272731B (it) 1993-10-18 1993-10-18 Attuatore lineare con ammortizzatore pneumatico regolabile in posizione

Publications (1)

Publication Number Publication Date
EP0648941A1 true EP0648941A1 (de) 1995-04-19

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EP94116318A Ceased EP0648941A1 (de) 1993-10-18 1994-10-17 Pneumatisches Stellorgan mit einstellbarer Endlagen- und Dämpfungseinrichtung

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EP (1) EP0648941A1 (de)
IT (1) IT1272731B (de)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0778107A1 (de) * 1995-12-05 1997-06-11 TÜNKERS MASCHINENBAU GmbH Kniehebelspannvorrichtung
EP0837248A3 (de) * 1996-10-15 1998-10-28 Ab Rexroth Mecman Druckmittelzylinder
EP1074750A2 (de) 1999-08-04 2001-02-07 UNIVER S.p.A. Druckmittelzylinder mit Enddämpfung und Geschwindigkeitssteuervorrichtung
US6382074B1 (en) 1999-03-29 2002-05-07 Luciano Migliori Pneumatic cylinder with damping device
US6764118B2 (en) 2002-09-11 2004-07-20 Autoliv Asp, Inc. Active bumper assembly
US6907817B2 (en) 2002-07-11 2005-06-21 Autoliv Asp, Inc. Linear actuator
US6942261B2 (en) 2003-08-14 2005-09-13 Autoliv Asp, Inc. Linear actuator with an internal dampening mechanism
EP1574722A3 (de) * 2004-03-12 2005-10-19 Bosch Rexroth Teknik AB Dämpfungsvorrichtung
US7121538B2 (en) 2001-05-31 2006-10-17 Stromsholmen Ab Arrangement at a press tool for breaking the piston/piston rod of a gas spring
US7182191B2 (en) 2002-07-11 2007-02-27 Autoliv Asp, Inc. Motion damper
US7303040B2 (en) 2004-05-18 2007-12-04 Autolive Asp, Inc. Active vehicle hood system and method
CN102889262A (zh) * 2012-09-12 2013-01-23 中国人民解放军总后勤部建筑工程研究所 一种缸筒浮动的组合式液压缸
WO2012112974A3 (en) * 2011-02-18 2013-03-28 Curtiss-Wright Controls, Inc. Hydraulic-pneumatic actuator
ITPR20120002A1 (it) * 2012-01-31 2013-08-01 Gea Procomac Spa Cilindro pneumatico e apparato di trasporto aereo di contenitori impiegante tale cilindro pneumatico
CN115992860A (zh) * 2023-03-20 2023-04-21 泰州市荣贵机械制造有限公司 一种可调节式阻尼器

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3626807A (en) * 1969-10-21 1971-12-14 Kenneth B Shartzer Adjustable stroke cylinders
FR2347556A1 (fr) * 1976-04-07 1977-11-04 Voest Ag Verin a piston et cylindre a course reglable
EP0005407A1 (de) * 1978-05-05 1979-11-14 Climax France S.A. Einrichtung zur Endlagenbremsung und/oder -beschleunigung für abwechselnd hin- und hergehende Elemente
FR2560302A1 (fr) * 1984-02-24 1985-08-30 Festo Kg Verin a piston et cylindre
DE3540416A1 (de) * 1985-11-14 1987-05-21 Bernard Helga Pneumatik-zylinder mit stufenlos einstellbarem hub und beidseitig wirkender endlagendaempfung
DE8904361U1 (de) * 1989-04-07 1989-06-15 Prewa Verpackungsmaschinenbau Gmbh, 6305 Buseck, De

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3626807A (en) * 1969-10-21 1971-12-14 Kenneth B Shartzer Adjustable stroke cylinders
FR2347556A1 (fr) * 1976-04-07 1977-11-04 Voest Ag Verin a piston et cylindre a course reglable
EP0005407A1 (de) * 1978-05-05 1979-11-14 Climax France S.A. Einrichtung zur Endlagenbremsung und/oder -beschleunigung für abwechselnd hin- und hergehende Elemente
FR2560302A1 (fr) * 1984-02-24 1985-08-30 Festo Kg Verin a piston et cylindre
DE3540416A1 (de) * 1985-11-14 1987-05-21 Bernard Helga Pneumatik-zylinder mit stufenlos einstellbarem hub und beidseitig wirkender endlagendaempfung
DE8904361U1 (de) * 1989-04-07 1989-06-15 Prewa Verpackungsmaschinenbau Gmbh, 6305 Buseck, De

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0778107A1 (de) * 1995-12-05 1997-06-11 TÜNKERS MASCHINENBAU GmbH Kniehebelspannvorrichtung
EP0837248A3 (de) * 1996-10-15 1998-10-28 Ab Rexroth Mecman Druckmittelzylinder
US6382074B1 (en) 1999-03-29 2002-05-07 Luciano Migliori Pneumatic cylinder with damping device
EP1074750A2 (de) 1999-08-04 2001-02-07 UNIVER S.p.A. Druckmittelzylinder mit Enddämpfung und Geschwindigkeitssteuervorrichtung
US7121538B2 (en) 2001-05-31 2006-10-17 Stromsholmen Ab Arrangement at a press tool for breaking the piston/piston rod of a gas spring
US6907817B2 (en) 2002-07-11 2005-06-21 Autoliv Asp, Inc. Linear actuator
US7182191B2 (en) 2002-07-11 2007-02-27 Autoliv Asp, Inc. Motion damper
US6764118B2 (en) 2002-09-11 2004-07-20 Autoliv Asp, Inc. Active bumper assembly
US6942261B2 (en) 2003-08-14 2005-09-13 Autoliv Asp, Inc. Linear actuator with an internal dampening mechanism
EP1574722A3 (de) * 2004-03-12 2005-10-19 Bosch Rexroth Teknik AB Dämpfungsvorrichtung
US7303040B2 (en) 2004-05-18 2007-12-04 Autolive Asp, Inc. Active vehicle hood system and method
WO2012112974A3 (en) * 2011-02-18 2013-03-28 Curtiss-Wright Controls, Inc. Hydraulic-pneumatic actuator
ITPR20120002A1 (it) * 2012-01-31 2013-08-01 Gea Procomac Spa Cilindro pneumatico e apparato di trasporto aereo di contenitori impiegante tale cilindro pneumatico
CN102889262A (zh) * 2012-09-12 2013-01-23 中国人民解放军总后勤部建筑工程研究所 一种缸筒浮动的组合式液压缸
CN102889262B (zh) * 2012-09-12 2015-04-15 中国人民解放军总后勤部建筑工程研究所 一种缸筒浮动的组合式液压缸
CN115992860A (zh) * 2023-03-20 2023-04-21 泰州市荣贵机械制造有限公司 一种可调节式阻尼器

Also Published As

Publication number Publication date
ITMI932209A0 (it) 1993-10-18
IT1272731B (it) 1997-06-26
ITMI932209A1 (it) 1995-04-18

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