US3915070A - Apparatus for indicating the position of the piston of a fluidic actuator - Google Patents

Apparatus for indicating the position of the piston of a fluidic actuator Download PDF

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Publication number
US3915070A
US3915070A US408198A US40819873A US3915070A US 3915070 A US3915070 A US 3915070A US 408198 A US408198 A US 408198A US 40819873 A US40819873 A US 40819873A US 3915070 A US3915070 A US 3915070A
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United States
Prior art keywords
piston
actuator
cylinder
gear
rotation
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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
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US408198A
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English (en)
Inventor
Pierre H Mailliet
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Paul Wurth SA
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Anciens Etablissements Paul Wurth SA
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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
    • F15B15/28—Means for indicating the position, e.g. end of stroke
    • F15B15/2815—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT
    • F15B15/2823—Position sensing, i.e. means for continuous measurement of position, e.g. LVDT by a screw mechanism attached to the piston

Definitions

  • the apparatus 116/127 comprises means positioned within the actuator cylin- [51] Int. Cl. F01B 31/12 der and coupled to the Piston for Converting longitudi' [58] Field 01 Search 116/124 R, 124 A, 124 F, 1191 motion of the piston I9 rotary motion which is 1 16/127; 91/1, 61; 60/699; 92/5 R, 31, 33, transmitted out of the cylinder to a suitable indicator.
  • the present invention relates to the determination of the position of movable members and particularly of longitudinally movable members which are moved in response to a pressurized fluid. More specifically, this invention is directed to means for accurately and continuously determining the position of the piston of a hydraulically or pneumatically operated actuator in a manner which does not require contact with the actuator output shaft or to a load coupled thereto. Accordingly, the general objects of the present invention are to provide novel and improved methods and apparatus of such character.
  • the sensor portion of a positional measuring device for a hydraulic or pneumatically operated actuator must obviously be at least partly arranged within the piston cylinder.
  • the problems associated with sensing the position of a piston located within a cylinder and having no direct engagement point outside of the cylinder are substantial and numerous.
  • the means for transmitting a signal commensurate with piston longitudinal motion through the cylinder casing must be sealed against leakage at the comparatively high pressures which occur.
  • frictional contact must be minimized within the cylinder since any metal fragments resulting from abrasion will damage the piston rings and/or the cylinder walls thereby destroying the jack itself.
  • the piston in a hydraulic or pneumatically operated jack is provided with excellent guidance and support in its working or longitudinal direction, the piston is typically not restrained from rotation within the cylinder casing. The possibility of rotational motion obviously greatly complicates the problem of accurately sensing piston position within the cylinder and thereafter transmitting such motion outside of the cylinder.
  • Apparatus in accordance with the present invention includes means disposed within the cylinder of a fluid operated actuator for converting longitudinal movements of the piston into rotational motion which is transmitted through a cylinder wall to a suitable indicator.
  • Apparatus in accordance with the present invention is further characterized by means which prevents unintentional rotary motion of the longitudinal-torotational converting means, such as might be caused by rotation of the actuator piston, thereby insuring accurate positional measurements.
  • the piston of a hydraulically or pneumatically operated actuator, and possibly also the piston rod are provided with a recess or blind hole which extends inwardly from a first end of the piston.
  • An extension of the rotatable shaft penetrates the cylinder wall and is connected to an indicator located to the exterior of the cylinder.
  • a setting ring or nut is carried by the inner wall of the recess in the piston.
  • the setting ring moves with the piston and engages the portion of the shaft which functions as a worm gear whereby longitudinal movement of the setting ring results in rotation of the shaft.
  • apparatus in accordance with the present invention may also include means which guides the setting ring in the longitudinal direction while preventing rotational movement thereof.
  • the means for guiding the setting ring may takethe form of a slotted tube affixed to the cylinder cover plate and projecting into the piston recess.
  • the slotted tube when employed, will be rigid and will be coaxial with the setting ring; the setting ring being provided with wedges which travel in slots in the tube.
  • the setting ring is positioned to the interior of the slotted tube and is provided with means for simultaneously guiding and imparting rotation to the worm gear portion of the shaft.
  • the portion of the shaft which performs the function of worm gear was constructed such that a complete working stroke of the piston was converted into a complete or partial rotation of the shaft.
  • FIG. 1 is a longitudinal view, partly in section, of a portion of an actuator having incorporated therein the piston position measuring apparatus of a preferred embodiment of the present invention
  • FIG. 2 is a cross-sectional side view of the embodiment of FIG. 1 taken through the portion of the device located within the actuator cylinder;
  • FIG. 3 is a side elevation view, partly in section, of an indicating instrument which may be associated with the apparatus of FIG. 1.
  • FIG. 1 the cylinder of a fluid operated actuator is indicated at 6.
  • a cover plate 2 for a first end of cylinder 6 is affixed to the cylinder by means of bolts such as bolt 4.
  • a longitudinal movable piston 8 is located within cylinder 6; piston 8 being provided with sealing rings 10 and 12 in the conventional manner.
  • the piston 8 is attached to a piston rod 14; rod 14 ultimately being coupled to the load mechanism operated by the actuator.
  • the piston 8 is shown in its most inward position; i.e., at the beginning of a stroke.
  • the means whereby the operating fluid is supplied to the interior of the actuator cylinder has not been shown. It will be understood that the operating fluid will be delivered to the rear side of piston 8 via suitable passages provided therefore in cover plate 2 and, if necessary, operating fluid may be delivered to the other side of piston 8 via a port provided in the wall of cylinder 6.
  • longitudinal movements of piston 8 and piston rod 14 are converted into rotary movement of a shaft 16 and the rotational movement of shaft 16 is transmitted to an indicator located to the exterior of the actuator.
  • the foregoing objective is achieved by providing the piston 8 and rod 14 with a central recess or blind hole 18.
  • the shaft 16 is introduced into recess 18 and the recess and shaft are dimensioned such that the shaft does not leave the recess during the operating stroke of the piston.
  • the portion 7 of the shaft 16 which is located within the actuator cylinder and extends into recess 18 is constructed as elongated gear means as for example, an extended worm gear or as a square bar twisted about its longitudinal axis Drive means comprising a setting ring or nut 5 17, which may most clearly be seen from joint consideration of FIGS. 1 and 2, is mounted so as to move with piston 8.
  • the setting ring 17 is also mounted, in the manner to be described in detail below, so as to be restrained against rotation. The setting ring 17 engages and thus imparts rotational movement to the twisted square bar or gear comprising shaft 16.
  • the setting ring 17 is held in a piston rod insert 20 by means of contact with abutting face 22 of insert 20,
  • Insert 20 is screwed into an internal thread provided in the recess 18 of the piston-piston rod assembly.
  • the piston 8 and insert 20 can, if desired, be integral.
  • a slotted supporting tube is rigidly attached, for example by welding, to a base plate 28.
  • the base plate 28 is attached to cylinder cover plate 2 by means of bolts and 42.
  • the supporting pipe 30 also extends into recess 18 in the piston-piston rod assembly.
  • the supporting tube 30 is provided, in the disclosed embodiment, with two longitudinally extending grooves 32 and 34.
  • the setting ring or nut 17 is shaped so as to define a pair of generally coaxial passages. The innermost of these passages is of suitable shape so as to engage the twisted square bar comprising shaft 16.
  • the second or outwardly disposed passage in nut 17 receives the slotted support tube 30.
  • the setting ring 17 is provided with inwardly extending longitudinal projections 36 and 38 which respectively engage grooves 32 and 34 of the supporting pipe 30. Accordingly, the setting ring 17 is guided in the longitudinal direction along the supporting tube 30 and can not rotate with respect thereto.
  • the setting ring or nut 17, although an integral member, may be considered as two elements; a first element being located outside of the supporting tube 30 and the second element being located within the tube 30, the two elements being interconnected by the slot in tube 30 as shown in FIG. 2.
  • the portion of the setting ring 17 located to the exterior of the support tube 30 is carried longitudinally by piston 8 via insert 20 and, as noted, rotational movement of setting ring 17 is prevented by means of the engagement of projections 36 and 38 on ring 17 with grooves 32 and 34 of tube 30.
  • sufficient clearance is provided between tube 30, setting ring 17 and shaft portion 7 of 16 so that excessive abrasion or friction is avoided and maximum measuring precision is insured.
  • the piston 8 and piston rod 14 can rotate without influencing the longitudinal position measurement.
  • the shaft 16, or more precisely a cylindrical extension thereof, is passed out of the actuator cylinder through an aperture provided in the cylinder cover plate 2.
  • the aforementioned base plate 28, in the manner to be described below, provides for the support of shaft 16 as it extends out of the actuator cylinder.
  • a sealing ring 44 insures against leakage between the interior and exterior of the cylinder betweenplates 2 and
  • the base plate 28 is also provided with a central aperture.
  • Bearing means for the mounting of shaft 16 are positioned in the aperture in plate 28 in the manner shown; the bearings being indicated at 46, 48 and 50.
  • the bearings 46, 48 and 50 are located against a internal shoulder in the aperture in plate 28 and are restrained against longitudinal movement in the opposite direction by means of a bearing bracket 52; bracket 52 in turn being attached to base plate 28 via bolts 54 and 56.
  • a sealing ring 58 is provided to prevent leakage of pressurized fluid from the interior of the actuator cylinder to the outer atmosphere past the supporting bearings for shaft 16.
  • the bearing bracket 52 carries a gland 60 to provide additional sealing.
  • the end of shaft 16 which extends out of the actuator; i.e., the portion of the shaft which extends outwardly past the base plate 28, is provided with a keyway 62.
  • the keyway 62 permits the coupling of shaft 16 to a position indicator.
  • shaft 16 may be rotatably supported at its inwardly disposed end in the manner shown in FIG. 1.
  • apparatus 164 which is affixed to the slotted supporting pipe 30 and is provided with a ball bearing 166; bearing 166 receiving a cylindrical tip portion .of shaft 16.
  • the keyway 62 of shaft 16 may be engaged by a connecting member 64.
  • Connecting member 64 is rigidly and eccentrically coupled to a transfer arm 66 which, in turn, drives a shaft 68.
  • shaft 68 is supported and mounted in a bearing block 70 which is attached, by means of a plate 72, to the outer casing of the actuator.
  • the shaft 68 extends through plate 72 and is connected to a box nut 76 via a coupling slip ring 74.
  • An indicator finger or dial 78 is attached, in any suitable manner, to the box nut 76.
  • the coupling slip ring 74 is retained by means of a further ring 80 afiixed to shaft 68 in the manner shown.
  • the box nut 70 is elastically and uniformly urged against the slip ring 74 by means of the internal spiral spring 82.
  • the elastic coupling of the box nut to the slip ring prevents bending of the indicator dial or finger 78 in the event of an accidental blockage of the natural movement thereof.
  • the attachment plate 72 also serves to support an indicator panel 84 which is positioned bethe quantity of packing material expelled is of interest to the operator, who must due to safety considerations remain a considerable distance from the tap hole, and may be determined as a function of the longitudinal furnace tap hole plugging machine. In such clay guns movement of a hydraulically operated piston.
  • the present invention comprises an accurate and substantially maintenance-free means for determining the position of the piston of a hydraulically or pneumatically operated actuator.
  • the conversion of the longitudinal movement of the piston into the rotation of an output shaft greatly facilitates solution of the problem of providing adequate sealing'between the interior of the actuator and the outside atmosphere and,-in fact, permits such sealing to be achieved with conventional apparatus.
  • the incorporation of the slotted supporting pipe 30 of the present invention permits the above described measuring device to be utilized in apparatus wherein the piston and piston rod are not axially aligned.
  • the apparatus of the present invention can be universally employed as a result of the independence of the measuring device from the particular load on the actuator.
  • Apparatus for determining the position of a piston of a fluid operated actuator the piston being movable longitudinally within a cylinder and being provided with a recess in a first end thereof, the position determining. apparatus comprising:
  • drive means mounted on the actuator piston for movement therewith, said drive means engaging said gear means, longitudinal motion of the actuator piston with respect to said gear means being coupled to said gear means by said drive means and producing rotation of said gear means;

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)
US408198A 1972-10-23 1973-10-19 Apparatus for indicating the position of the piston of a fluidic actuator Expired - Lifetime US3915070A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
LU66347 1972-10-23

Publications (1)

Publication Number Publication Date
US3915070A true US3915070A (en) 1975-10-28

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ID=19727186

Family Applications (1)

Application Number Title Priority Date Filing Date
US408198A Expired - Lifetime US3915070A (en) 1972-10-23 1973-10-19 Apparatus for indicating the position of the piston of a fluidic actuator

Country Status (8)

Country Link
US (1) US3915070A (enrdf_load_stackoverflow)
BE (1) BE806317A (enrdf_load_stackoverflow)
DE (1) DE2344143A1 (enrdf_load_stackoverflow)
ES (1) ES419549A1 (enrdf_load_stackoverflow)
FR (1) FR2203948B1 (enrdf_load_stackoverflow)
GB (1) GB1440353A (enrdf_load_stackoverflow)
IT (1) IT998765B (enrdf_load_stackoverflow)
LU (1) LU66347A1 (enrdf_load_stackoverflow)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1981003679A1 (en) * 1980-06-16 1981-12-24 W Foxwell Power cylinder with internally mounted position indicator
US4523514A (en) * 1981-09-08 1985-06-18 Deere & Company Position sensing cylinder
US4536130A (en) * 1984-06-18 1985-08-20 Dunham-Bush, Inc. Simplified unloader indicator for helical screw rotary compressor
US4552055A (en) * 1981-02-09 1985-11-12 Prince Manufacturing Company Power cylinder with internally mounted position indicator
US5488860A (en) * 1993-12-29 1996-02-06 E-Systems, Inc. Apparatus for determining the position of a piston in a fluidic actuator
US5967017A (en) * 1995-11-24 1999-10-19 Georgia Tech Research Corporation Rotational displacement apparatus with ultra-low torque and high thrust load capability
US20050000350A1 (en) * 2001-12-20 2005-01-06 Timo Tikkanen Actuator cylinder
US20050007099A1 (en) * 2003-07-07 2005-01-13 Hamasagar Arun M. Position sensing method and apparatus for a linkage system
US20050189937A1 (en) * 2002-12-31 2005-09-01 Blubaugh James F. Position sensing cylinder cap for ease of service and assembly
US20050263001A1 (en) * 2004-05-28 2005-12-01 Caterpillar Inc. Hydraulic cylinder having a snubbing valve
US20070048116A1 (en) * 2005-07-18 2007-03-01 Thomas Friedrich Lifting/pivoting apparatus for loading board walls and/or loading ramps
US20110233441A1 (en) * 2008-12-16 2011-09-29 Allan Graeme Miners Linear actuator with internal linear to rotary conversion and external rotary component
US20220031544A1 (en) * 2020-07-29 2022-02-03 Hawe Hydraulik Se Cylinder device for a hydraulic lifting device with distance measurement, hydraulic lifting device, chassis and mobile device
US11779501B2 (en) * 2019-09-17 2023-10-10 Engle Dental Systems, LLC Traverse dental chair and a sensor assembly for monitoring positions thereof

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3229945C2 (de) * 1982-08-12 1986-06-05 Mannesmann Rexroth GmbH, 8770 Lohr Vorrichtung zur Anzeige des Kolbenhubes bei einem hydraulischen Zylinder
DE19933073A1 (de) * 1999-07-19 2001-01-25 Claas Industrietechnik Gmbh Vorrichtung zur Erfassung der Lage eines Kolbens
DE102020107647A1 (de) 2020-03-13 2021-09-16 Wollin Gmbh Dosiervolumenmesseinrichtung

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US243450A (en) * 1881-06-28 lafargkje
US2704047A (en) * 1953-03-05 1955-03-15 Lushenko Gordon Indicating mechanism for ram operated agricultural tool
US2936737A (en) * 1955-07-25 1960-05-17 Miller J Carter Rotary actuator
US3077179A (en) * 1961-08-22 1963-02-12 Evanson Emil Position indicator for elongatable actuators such as hydraulic cylinders
US3186311A (en) * 1962-10-03 1965-06-01 Carl M Carlson Air impulse counter
US3386340A (en) * 1965-11-24 1968-06-04 Elisworth C. Engle Fluid power drive unit having rotary and reciprocatory movement
US3633534A (en) * 1970-01-07 1972-01-11 Sperry Rand Corp Mechanical annunciator for indicating the position of the actuation shaft of a selector switch
US3766831A (en) * 1971-12-09 1973-10-23 Southwest Res Inst Compound axial torsional hydraulic actuator

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE7201445U (de) * 1972-04-06 Weiste H Langenveranderhcher hydraulischer Stellzylinder
US3398484A (en) * 1965-06-04 1968-08-27 Katsumura Toru Car door actuator
US3363434A (en) * 1965-08-26 1968-01-16 Lokomotivbau Elektrotech Device for protecting a shaft against condensation of vapor
GB1160624A (en) * 1966-07-05 1969-08-06 Gen Electric Improvements in Hydraulic Actuators
DE1299432B (de) * 1967-12-30 1969-07-17 Maurer Ludwig Verfahren und Vorrichtung zur Stellwegmessung bei einer mit einem Druckmedium beaufschlagten Kolben-zylinder-Einheit
DE1784892C3 (de) * 1968-07-09 1975-09-11 Fritz Dipl.-Ing. 3001 Anderten Engelbart Vorrichtung zur Abwasserreinigung
NO123671B (enrdf_load_stackoverflow) * 1968-12-30 1971-12-27 Norsk Hydro Verksteder A S

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US243450A (en) * 1881-06-28 lafargkje
US2704047A (en) * 1953-03-05 1955-03-15 Lushenko Gordon Indicating mechanism for ram operated agricultural tool
US2936737A (en) * 1955-07-25 1960-05-17 Miller J Carter Rotary actuator
US3077179A (en) * 1961-08-22 1963-02-12 Evanson Emil Position indicator for elongatable actuators such as hydraulic cylinders
US3186311A (en) * 1962-10-03 1965-06-01 Carl M Carlson Air impulse counter
US3386340A (en) * 1965-11-24 1968-06-04 Elisworth C. Engle Fluid power drive unit having rotary and reciprocatory movement
US3633534A (en) * 1970-01-07 1972-01-11 Sperry Rand Corp Mechanical annunciator for indicating the position of the actuation shaft of a selector switch
US3766831A (en) * 1971-12-09 1973-10-23 Southwest Res Inst Compound axial torsional hydraulic actuator

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1981003679A1 (en) * 1980-06-16 1981-12-24 W Foxwell Power cylinder with internally mounted position indicator
US4386552A (en) * 1980-06-16 1983-06-07 Foxwell W John Power cylinder with internally mounted position indicator
US4552055A (en) * 1981-02-09 1985-11-12 Prince Manufacturing Company Power cylinder with internally mounted position indicator
US4523514A (en) * 1981-09-08 1985-06-18 Deere & Company Position sensing cylinder
US4536130A (en) * 1984-06-18 1985-08-20 Dunham-Bush, Inc. Simplified unloader indicator for helical screw rotary compressor
US5488860A (en) * 1993-12-29 1996-02-06 E-Systems, Inc. Apparatus for determining the position of a piston in a fluidic actuator
US5967017A (en) * 1995-11-24 1999-10-19 Georgia Tech Research Corporation Rotational displacement apparatus with ultra-low torque and high thrust load capability
US6968771B2 (en) * 2001-12-20 2005-11-29 Alamarin-Jet Oy Actuator cylinder
US20050000350A1 (en) * 2001-12-20 2005-01-06 Timo Tikkanen Actuator cylinder
US20050189937A1 (en) * 2002-12-31 2005-09-01 Blubaugh James F. Position sensing cylinder cap for ease of service and assembly
US7023199B2 (en) 2002-12-31 2006-04-04 Caterpillar Inc. Position sensing cylinder cap for ease of service and assembly
US20050007099A1 (en) * 2003-07-07 2005-01-13 Hamasagar Arun M. Position sensing method and apparatus for a linkage system
US20050263001A1 (en) * 2004-05-28 2005-12-01 Caterpillar Inc. Hydraulic cylinder having a snubbing valve
US7121185B2 (en) 2004-05-28 2006-10-17 Caterpillar Inc. Hydraulic cylinder having a snubbing valve
US20070048116A1 (en) * 2005-07-18 2007-03-01 Thomas Friedrich Lifting/pivoting apparatus for loading board walls and/or loading ramps
US20110233441A1 (en) * 2008-12-16 2011-09-29 Allan Graeme Miners Linear actuator with internal linear to rotary conversion and external rotary component
US11779501B2 (en) * 2019-09-17 2023-10-10 Engle Dental Systems, LLC Traverse dental chair and a sensor assembly for monitoring positions thereof
US12213924B2 (en) 2019-09-17 2025-02-04 Engle Dental Systems, LLC Traverse dental chair and a sensor assembly for monitoring positions thereof
US20220031544A1 (en) * 2020-07-29 2022-02-03 Hawe Hydraulik Se Cylinder device for a hydraulic lifting device with distance measurement, hydraulic lifting device, chassis and mobile device
US12085101B2 (en) * 2020-07-29 2024-09-10 Hawe Hydraulik Se Cylinder device for a hydraulic lifting device with distance measurement, hydraulic lifting device, chassis and mobile device

Also Published As

Publication number Publication date
LU66347A1 (enrdf_load_stackoverflow) 1973-01-23
DE2344143C2 (enrdf_load_stackoverflow) 1987-06-11
FR2203948A1 (enrdf_load_stackoverflow) 1974-05-17
DE2344143A1 (de) 1974-04-25
BE806317A (fr) 1974-02-15
GB1440353A (en) 1976-06-23
FR2203948B1 (enrdf_load_stackoverflow) 1978-09-08
ES419549A1 (es) 1976-05-01
IT998765B (it) 1976-02-20

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