US3541925A - Device for detecting the end of travel of jack pistons - Google Patents

Device for detecting the end of travel of jack pistons Download PDF

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Publication number
US3541925A
US3541925A US757378A US3541925DA US3541925A US 3541925 A US3541925 A US 3541925A US 757378 A US757378 A US 757378A US 3541925D A US3541925D A US 3541925DA US 3541925 A US3541925 A US 3541925A
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United States
Prior art keywords
pressure
jack
travel
distributor
switch
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Expired - Lifetime
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US757378A
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English (en)
Inventor
Gabriel L Guinot
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Poclain SA
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Poclain SA
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Publication date
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Publication of US3541925A publication Critical patent/US3541925A/en
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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
    • F15B15/28—Means for indicating the position, e.g. end of stroke
    • F15B15/2807—Position switches, i.e. means for sensing of discrete positions only, e.g. limit switches

Definitions

  • a device for detecting the end of travel of a piston in a double-acting jack cylinder fed by two feed conduits and a three-position distributor the device including a pressure distributor connected to the two feed conduits and adapted to be actuated by a predetermined pressure, so that a U.S.Cl 9l/l,92/5 Int. Cl ..F01b 25/26,
  • a main object of the present invention is to enable this kind of control to be effected, and more generally to permit the detection of end-of-travel positions of the pistons of hydraulic or pneumatic jacks, mounted notably in earth-working machines, without the addition of supplementary connections (hydraulic, pneumatic, electrical, etc.) between these jacks and the main fluid source.
  • an end-oftravel detection device for the piston of a double-acting jack, fed from a main hydraulic or pneumatic source through the agency of a three-position distributor, characterized in that it comprises in combination end-of-travel valves of known type mounted on the piston and adapted to place the two chambers of the jack in communication, a movable abutment, the control of which is coupled to that of the distributor, the abutment being adapted, according to whether the distributor is in its neutral position or not, to open or close the movable contacts of an electrical circuit in which is included a light indicator and a pressure switch adapted to operate at a certain predetermined pressure and connected by means of a pressure distributor to two pressure fluid feed conduits of the jack, the pressure switch being inserted in said electrical circuit.
  • FIG. of which is a diagrammatic representation of the detection device of the invention.
  • a double-acting hydraulic jack 1 supplied with fluid under pressure by two conduits 2 from a main hydraulic source constituted by a pump 3 and a reservoir 4.
  • the jack is fixed at the end 5 of the cylinder and by means of the end 6 of the piston rod 7 is connected to a bucket for example (not shown).
  • the piston 7 of the jack 1 is provided with end-of-travel valves 8 of known type permitting communication between the two chambers of the jack 1 when the piston 7 is in abutment against one or other of its faces.
  • a three-position distributor 9 is interposed in the twojac k supply conduits 2 enabling one or the other'chamber of the jack 1 to be fed with fluid under pressure or enabling pressure fluid to be cut off from the jack.
  • the control of the distributor 9 is coupled to that of a movable abutment 10 which is also adapted to occupy one of three positions, namely a rest position (as shown in the drawing) and corresponding to the neutral position of the distributor 9, and two extreme positions corresponding respectively to the two other positions of the distributor 9.
  • the device also comprises a pressure switch 14 which may be adjusted to set the pressure at which it will be actuated, this switch being supplied with fluid under pressure from two conduits 2 by means of a pressure distributor IS.
  • a movable contact 16 of the switch is inserted in the electrical circuit of the light indicator 13.
  • pressure distributor there will be understood a hydraulic or pneumatic circuit of known principle adapted to select for example, and in the present case, the highest feed pressure between two possible fluid sources.
  • a circuit includes a ball moving in a recess and blocking the inlet conduit of the smallest of the two pressures, the other conduit being in direct communication .with the output of the circuit.
  • the device operatesas follows:
  • the pressure switch 14 is adjustable initially so that the contact '16 is open when the pressure acting on the pressure switch is greater than a predetermined level and closed when this pressure falls below the given level.
  • the movable abutment 10 When the distributor 9 is in the neutral position, the movable abutment 10 is also in the neutral position and the electrical circuit of the light indicator is open.
  • This circuit therefore remainsopen whether the movable contact 16 isopen or closed, i.e. whether or not a static pressure prevails in the conduits 2.
  • the actuating pressure of the pressure switch 14 is set as a function of the pressure losses of the hydraulic circuit when the two chambers of the jack 1 areplaced in communication.
  • a damping valve 17 in each feed conduit 2 of the jack 1 between the distributor 9 and the pressure distributor 15 can be used to eliminate such a risk.
  • This valve defines a pressure slightly greater than that at which the pressure switch 14 is setto operate.
  • Sucha device is more particularly used when a deep-drilling operation is to be effected.
  • Such equipment enables the position of the bucket scoops of the machine effecting the drilling to be determined and ensures that the bucket is closed before being raised.
  • the present invention is not limited to the embodiment described and shown above, but covers all variants thereof.
  • a device for detecting the limits of travel of a piston in a fluid cylinder provided with a pair of fluid supply lines operatively interconnecting the ends of said cylinder with a supply of fluid under pressure, and having means for selectively communicating one of said fluid supply lines with said fluid supply source, comprising an electrical circuit having electrically actuated indicating means and first and second switches nor mally disposed in their open positions, means operatively interconnecting said'selectively communicating means and said first switch of said electrical circuit for closing said first switch when said selectively communicating means communicates either'of said fluidsupply lines with said fluid supply source, means responsive to a predetermined pressure in either of said fluid supply lines operatively connected to said second switch of said electrical circuitfor closing said second switch upon sensing said predetermined pressure in either of said fluid supply lines, and said piston having valve means which opens at the end of piston travel for intercommunicating the fluid chambers of said cylinder.
  • said electrically actuated indicating means comprises a lamp energized by said electrical circuit.
  • a device wherein said means operapressure-sensitive switch having a movable actuating member lines interconnecting said fluid supply lines and said pressurewith an abutment engageable with a contact element of said sensitive switch, and means for selectively communicating second switch to close said contact element, a pair of fluid said fluid pressure switch with one of said fluid lines.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Actuator (AREA)
  • Earth Drilling (AREA)
US757378A 1967-09-21 1968-09-04 Device for detecting the end of travel of jack pistons Expired - Lifetime US3541925A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR121772A FR1544188A (fr) 1967-09-21 1967-09-21 Dispositif de détection de fin de course de pistons de vérins

Publications (1)

Publication Number Publication Date
US3541925A true US3541925A (en) 1970-11-24

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ID=8638719

Family Applications (1)

Application Number Title Priority Date Filing Date
US757378A Expired - Lifetime US3541925A (en) 1967-09-21 1968-09-04 Device for detecting the end of travel of jack pistons

Country Status (4)

Country Link
US (1) US3541925A (fr)
ES (1) ES358380A1 (fr)
FR (1) FR1544188A (fr)
GB (1) GB1222840A (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3691902A (en) * 1971-07-13 1972-09-19 Us Army Monitoring system for pneumatic cylinder
US4508327A (en) * 1982-01-15 1985-04-02 Maschinenfabrik Hilma Gmbh Swing clamp
DE3417447A1 (de) * 1984-05-11 1985-11-21 E.P.E. Budde GmbH, 5980 Werdohl Vorrichtung zur erfassung der endlagen eines hydraulikzylinders
US4779513A (en) * 1984-06-11 1988-10-25 Nippon Joucomatic Co., Ltd. Pneumatic cylinder with rod braking and decelerating mechanism
US5587536A (en) * 1995-08-17 1996-12-24 Rasmussen; John Differential pressure sensing device for pneumatic cylinders
US5778753A (en) * 1995-11-29 1998-07-14 Parker Hannifin Pty Limited Pneumatic or hydraulic cylinders
EP1195529A1 (fr) * 2000-10-06 2002-04-10 Ando Seisakujo Co. Ltd. Capteur pour commande de vérin, et vérin muni d'un tel dispositif
US6813987B1 (en) * 1999-08-16 2004-11-09 Hartmann & Laemmle Gmbh & Co. Kg Electrohydraulic monitoring device for a dual effect hydraulic cylinder

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4002103A (en) * 1974-07-01 1977-01-11 The West Company Reciprocating apparatus with a controllable dwell time at each end of the stroke
DE9411939U1 (de) * 1994-07-22 1994-09-15 Paul Pleiger Maschinenfabrik GmbH & Co KG, 58452 Witten Vorrichtung für die Stellungsanzeige bei hydraulisch betätigten Armaturen

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3691902A (en) * 1971-07-13 1972-09-19 Us Army Monitoring system for pneumatic cylinder
US4508327A (en) * 1982-01-15 1985-04-02 Maschinenfabrik Hilma Gmbh Swing clamp
DE3417447A1 (de) * 1984-05-11 1985-11-21 E.P.E. Budde GmbH, 5980 Werdohl Vorrichtung zur erfassung der endlagen eines hydraulikzylinders
US4779513A (en) * 1984-06-11 1988-10-25 Nippon Joucomatic Co., Ltd. Pneumatic cylinder with rod braking and decelerating mechanism
US5587536A (en) * 1995-08-17 1996-12-24 Rasmussen; John Differential pressure sensing device for pneumatic cylinders
US5778753A (en) * 1995-11-29 1998-07-14 Parker Hannifin Pty Limited Pneumatic or hydraulic cylinders
US6813987B1 (en) * 1999-08-16 2004-11-09 Hartmann & Laemmle Gmbh & Co. Kg Electrohydraulic monitoring device for a dual effect hydraulic cylinder
EP1195529A1 (fr) * 2000-10-06 2002-04-10 Ando Seisakujo Co. Ltd. Capteur pour commande de vérin, et vérin muni d'un tel dispositif
US6786129B2 (en) 2000-10-06 2004-09-07 Ando Seisakujo Co., Ltd. Sensor for cylinder control, and cylinder device incorporating the same

Also Published As

Publication number Publication date
ES358380A1 (es) 1970-04-16
FR1544188A (fr) 1968-10-31
GB1222840A (en) 1971-02-17

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