US3872778A - Hydraulic actuator - Google Patents

Hydraulic actuator Download PDF

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Publication number
US3872778A
US3872778A US388667A US38866773A US3872778A US 3872778 A US3872778 A US 3872778A US 388667 A US388667 A US 388667A US 38866773 A US38866773 A US 38866773A US 3872778 A US3872778 A US 3872778A
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US
United States
Prior art keywords
plunger
bore
cylinder
plunger rod
lever
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
US388667A
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English (en)
Inventor
Palle Hein Christiansen
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.)
Novenco Building and Industry AS
Original Assignee
Nordisk Ventilator Co
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 Nordisk Ventilator Co filed Critical Nordisk Ventilator Co
Application granted granted Critical
Publication of US3872778A publication Critical patent/US3872778A/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
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/1423—Component parts; Constructional details
    • F15B15/1457—Piston rods
    • F15B15/1461—Piston rod sealings

Definitions

  • ABSTRACT A hydraulic actuator comprising a fluid-containing cylinder with a cover incorporating a bore in which a ,plunger is displaceably journalled with a leak-proof s'aiingg s aid plunger beiii g c onnecte d rigidly with a plunger rod which is connected directly and pivotably with a lever which is journalled to be pivotable relative to the cylinder through a predetermined angle of rotation, whereby to impress a rocking movement on the plunger rod during axial displacement of the plunger.
  • the length of the bore is at least equal to the maximum axial travel of the plunger and the diameter of the bore differs at every point and in any position from that of the plunger by an amount exceeding twice the possible lateral movement of the plunger at that point caused by said rocking movement of the plunger rod, the leak-proof sealing between the plunger and the bore being effected by an O-ring, a diameter of which forms an axis of rotation for the plunger rod.
  • the present invention relates to a hydraulic actuator consisting of a cylinder with a displaceable plunger passing leak-proof through a bore in a cover on the cylinder, a plunger rod connected rigidly to the plunger being coupled to a lever which is pivotable relative to the cylinder through a predetermined angle of rotation.
  • Actuators of this kind operate in such a way that a variation in the volume of fluid contained in the cylinder results in a corresponding, oppositely-directed variation in the volume of the part of the plunger located in the fluid and thus in a corresponding displacement of the plunger.
  • the variation in the volume of the fluid can be caused by a variation in temperature or by the supply or removal, respectively, of an additional quantity of fluid through a tube by means of a control device which may be a temperature sensor or a control cylin' der with a plunger mounted therein.
  • the plunger is controlled in such a way that it performs together with the plunger rod a purely axial movement which necessitates that the connection between the plunger rod and the lever posseses a mobility which may be obtained by means of an additional lever or by engagement between a pin on one of said two members and an oblong hole in the other member. In both instances this results in a certain amount of play in the connection so that rocking movement of the lever does not accurately accompany the displacement of the plunger rod.
  • a hydraulic actuator comprising a fluid-containing cylinder, a cover fixed at one end of said cylinder and incorporating a bore, a plunger passing with a leak-proof sealing through said bore and being displaceable between two extreme positions by varying the fluid volume in the cylinder, a plunger rod connected rigidly to said plunger and a lever coupled to said plunger rod and being journalled to be pivotable relative to the cylinder through a predetermined angle of rotation, wherein the improvement comprises that the lever is connected directly and pivotably to the plunger rod and isjournalled at a point of rotation stationary relative to the cylinder, whereby to impress a rocking movement on the plunger rod during axial displacement of the plunger, the length of the bore being at least equal to the maximum axial travel of the plunger and the diameter of the bore differing at every point and in any position from that of the plunger by an amount exceeding twice the possible lateral movement of the plunger at that point caused by said rocking movement the plunger rod, the leakproof sealing between the bore and the plunge
  • this rocking movement can be reduced to the maximum possible extent by arranging the axis of the plunger to be approximately parallel to the axis of the bore in two positions, one of which lies approximately midway between one extreme position of the plunger and a central position between the two extreme positions and the other approximately midway between the central position of the plunger and the other extreme position.
  • FIG. ll shows an embodiment of an actuator according to the invention constructed as a thermostat
  • FIG. 2 shows a portion of a modified embodiment
  • the actuator illustrated in FIG. 1 consists of a cylinder 1 with a displacing plunger 2 passing through a bore 3 in the cover of the cylinder which, in the embodiment shown, is constructed as a sleeve 4
  • This sleeve 4 is axially displaceable in a bore in a top flange 5 which is rigidly connected to cylinder 1, a sealing being provided between sleeve 4 and top flange 5 by means of an O- ring 6.
  • lever 14 On the upper side of top piece It) and upright support 13 is mounted, at the upper end of which a lever 14 is pivotably journalled around a pin 15. In addition, lever 14 is pivotably connected by means of a pin 16 to the upper end of plunger rod 9.
  • Plunger rod 9 is passed unimpededly through an aperture 17 in top piece 10 and is surrounded by a sleeve 18 which is secured to the plunger by means of a pin a rivet 19.
  • the height of sleeve 18 is less than the internal distance between the upper side of sleeve 4 and the lower side of top piece 10 and, in the lowest position of plunger 2 the sleeve 18 is in abutment against sleeve 4, whereas, in the upper position of plunger 2, it is in abutment against top piece 10 and thus serves to determine the limits of travel of plunger 2.
  • Plunger 2 is sealed against the wall of bore 3 in sleeve 4 by means of an O-ring 20 which is retained in a circumferential groove in plunger 2.
  • the length of travel of plunger 2 determined by the sleeve has thus to be, at the most, equal to the axial length of bore 3 reduced by the thickness of O-ring 20.
  • cylinder 1 is completely closed by a bottom portion 21. It is filled with a fluid
  • the actuator is consequently capable of acting as a thermostat in which cylinder 1 simultaneously as a temperature sensor.
  • cylinder 1 By heating cylinder 1 and, thereby, the liquid contained therein, the volume of the fluid is increased and plunger 2 is displaced in a corresponing manner outof the cylinder thereby executing an axial movement in a upward direction.
  • the plunger In order to secure return movement the plunger is provided with an extension 22 projecting down into the cylinder and carrying, at its lower end, a sleeve 23, said extension being furthermore surrounded by a return spring 24 which is in contact with said sleeve 23 as well as sleeve 4.
  • the cylinder can be connected with an independent temperature sensor or another hydraulic operating means via a tube 25 such as indicated in dotted lines in FIG. 1.
  • Lever 14 may be connected, for example, to a damper in a ventilation system for adjusting said damper in dependence on temperature or to any other element that is to be controlled by hydraulic actuation.
  • plunger 2 is, on both sides of the'O-ring 20, proportioned with an outer diameter being so much smaller than the diameter of bore 3 that the rocking movement necessitated by the movement of pin .16 along a circular path can be superposed upon the axial movement of the plunger.
  • bore 3 may, in principle, extend in a fixed top piece.
  • an expansion of the fluid in cylinder 1 beyond the volume corresponding to the upper limit position of the plunger determined by sleeve 18 will result in an axial displacement of sleeve 4 against the action of springs 8 so that overloading will not give rise to destruction of the actuator.
  • the rocking movement performed by the plunger during the axial movement takes place, generally speaking, around an axis in the plane of O-ring 20 through the centre therof for which reason oppositely directed torsional stresses will appear in the two halves of the O-ring.
  • the axis of plunger 2 it is expedient for the axis of plunger 2 to coincide with the axis of bore 3 in two positions, one of which is approximately midway between one extreme position and the centre position of the plunger and the other approximately midway between the centre position of the plunger and the other extreme position.
  • FIG. 2 shows a modified construction of one portion of the actuator illustrated in FIG. 1 which essentailly only differs from the construction shown in FIG. 1 in that O-ring 20 is retained in a groove in a sleeve 27 cor- Plunger 28 is cylindrical and has a uniform diameter throughout its length, while bore 29 in sleeve 27 diverges conically to both sides of O-ring 20 so that the necessary play is obtained thereby for the rotary movement of the plunger during the axial movement.
  • a hydraulic actuator having a fluid-containing cylinder, a cover fixed at one end of said'cylinder and incorporating a bore, a plunger passing with a leakproof sealing through said bore and being displaceable between two extreme positions by varying the fluid volume in the cylinder, a plunger rod connected rigidly to said plunger and a lever coupled to said plunger rod and being journalled to be pivotable relative to the cylinder through a predetermined angle of rotation, wherein the improvement comprises a. the length of the bore is at least equal to the maximum axial travel of the plunger;
  • the diameter of the bore differs at every point and in any position from that of the plunger by an amount exceeding twice the possible lateral movement of the plunger at that point caused by a rocking movement of the plunger rod;
  • the leakproof sealing between the bore and the plunger is effected by an O-ring, a diameter of which forms an axis of rotation for the plunger rod, thereby enabling a rocking movement on the plunger rod during axial displacement of the plunger and the lever to be connected directly and pivotably to the plunger rod and journalled at a point of rotation stationary relative to the cylinder.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
  • Temperature-Responsive Valves (AREA)
US388667A 1972-08-21 1973-08-15 Hydraulic actuator Expired - Lifetime US3872778A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DK414172 1972-08-21

Publications (1)

Publication Number Publication Date
US3872778A true US3872778A (en) 1975-03-25

Family

ID=8130639

Family Applications (1)

Application Number Title Priority Date Filing Date
US388667A Expired - Lifetime US3872778A (en) 1972-08-21 1973-08-15 Hydraulic actuator

Country Status (8)

Country Link
US (1) US3872778A (US08188275-20120529-C00054.png)
JP (1) JPS5040975A (US08188275-20120529-C00054.png)
CA (1) CA963359A (US08188275-20120529-C00054.png)
DD (1) DD106445A5 (US08188275-20120529-C00054.png)
DE (1) DE2340982A1 (US08188275-20120529-C00054.png)
FR (1) FR2197124B1 (US08188275-20120529-C00054.png)
NL (1) NL7311446A (US08188275-20120529-C00054.png)
SE (1) SE380328B (US08188275-20120529-C00054.png)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080138681A1 (en) * 2006-12-07 2008-06-12 Canon Kabushiki Kaisha Fuel cell system

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US86974A (en) * 1869-02-16 Improvement in steam-engines
US1029143A (en) * 1910-05-20 1912-06-11 Lester M Rich Pump-cap.
US3695150A (en) * 1969-07-18 1972-10-03 Willi Salzmann Crank assemblies for machines having reciprocating pistons

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US86974A (en) * 1869-02-16 Improvement in steam-engines
US1029143A (en) * 1910-05-20 1912-06-11 Lester M Rich Pump-cap.
US3695150A (en) * 1969-07-18 1972-10-03 Willi Salzmann Crank assemblies for machines having reciprocating pistons

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080138681A1 (en) * 2006-12-07 2008-06-12 Canon Kabushiki Kaisha Fuel cell system

Also Published As

Publication number Publication date
CA963359A (en) 1975-02-25
SE380328B (sv) 1975-11-03
FR2197124B1 (US08188275-20120529-C00054.png) 1977-02-25
DD106445A5 (US08188275-20120529-C00054.png) 1974-06-12
NL7311446A (US08188275-20120529-C00054.png) 1974-02-25
JPS5040975A (US08188275-20120529-C00054.png) 1975-04-15
FR2197124A1 (US08188275-20120529-C00054.png) 1974-03-22
DE2340982A1 (de) 1974-03-07

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