EP0271456A2 - Appareil de commande de débit pour des pompes à piston à débit variable - Google Patents

Appareil de commande de débit pour des pompes à piston à débit variable Download PDF

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Publication number
EP0271456A2
EP0271456A2 EP87830429A EP87830429A EP0271456A2 EP 0271456 A2 EP0271456 A2 EP 0271456A2 EP 87830429 A EP87830429 A EP 87830429A EP 87830429 A EP87830429 A EP 87830429A EP 0271456 A2 EP0271456 A2 EP 0271456A2
Authority
EP
European Patent Office
Prior art keywords
axis
rotation
delivery
cam
pump
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.)
Granted
Application number
EP87830429A
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German (de)
English (en)
Other versions
EP0271456A3 (en
EP0271456B1 (fr
Inventor
Vincenzo Di Vincenzo
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.)
SIAPA SRL
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SIAPA SRL
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Filing date
Publication date
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Publication of EP0271456A2 publication Critical patent/EP0271456A2/fr
Publication of EP0271456A3 publication Critical patent/EP0271456A3/en
Application granted granted Critical
Publication of EP0271456B1 publication Critical patent/EP0271456B1/fr
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/12—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by varying the length of stroke of the working members
    • F04B49/123—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by varying the length of stroke of the working members by changing the eccentricity of one element relative to another element
    • F04B49/125—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by varying the length of stroke of the working members by changing the eccentricity of one element relative to another element by changing the eccentricity of the actuation means, e.g. cams or cranks, relative to the driving means, e.g. driving shafts
    • F04B49/126—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by varying the length of stroke of the working members by changing the eccentricity of one element relative to another element by changing the eccentricity of the actuation means, e.g. cams or cranks, relative to the driving means, e.g. driving shafts with a double eccenter mechanism

Definitions

  • the present invention relates to a delivery control­ling device for variable delivery piston pumps provided with a driving shaft bearing a cam for the operation of the pistons.
  • variable delivery displace­ment pumps are known to the state of the art, which are provided with various devices for modifying the delivery.
  • metering pumps are used for metering and feeding a liquid to a nozzle apparatus and for trans­ferring the liquid from a container to the tank of the agricultural machine.
  • Such metering pumps are generally provided with a cam and double acting plunger and are operated by a power output synchronized with the speed gear of the agricultural machine.
  • variable delivery pump must have a variable delivery to fit the various types of liquid to be treated. It has not been possible so far to realize a variable delivery pump for this function, such as to be particularly simple and precise in adjusting its output, and at the same time as free as possible from vibrations and mechanical failures.
  • the present invention solves this problem by resortivelying to an additional excentric or cam, besides the cam already mounted on the pump shaft. Moreover the entire delivery control device is coaxial to the axis of rotation of the shaft, so as to avoid undesired asimetrical and unbalanced elements which always involve an undesired stress on the parts of the machine, as well as vibrations and similar drawbacks.
  • the arrangement of the present invention is such that the transition from the minimum to the maximum delivery is graduated through a full turn of a control wheel, so that a more precise set of the pump delivery is obtained.
  • the delivery control device for a variable delivery piston pump pro­vided with a driving shaft bearing a cam and rotating about an axis of rotation for controlling the reciprocal motion of the pistons is characterized in that the driving shaft comprises a first shaft member coaxial to the axis of rotation and engagable with the power output of a motor, and a second shaft member integral with the first member, having a first shaft portion with a geometric axis excentric to the axis of rotation, with a fixed excentricity, and a second shaft portion coaxial to the axis of rotation having a cavity coaxial to said axis of rotation; a delivery controlling unit comprising a wheel integral with a pinion gear, both coaxial to said axis of rotation of the driving shaft, said delivery controlling unit being pivotally mounted within said coaxial cavity of the second portion of the second shaft member, and able to be locked with respect thereto; and a delivery adjusting unit comprising a cam slidingly engaged with the pump elements which operate the pistons and engaged with said
  • the vari­able delivery pump is a pump of a type with plungers (not shown in the drawings).
  • the structure of the pump comprises a driving shaft rotating about an axis of rotation A, this shaft being formed with a first member 1 coaxial to the axis of rotation A and mounted by supporting bearings 2, and a second shaft member comprising a first shaft portion indicated in 3 which is geometrically symmetrical with respect to an excentric geometric axis indicated in E, and a second shaft portion indicated in 4, which is coaxial or centered to the axis of rotation A and which is integral with said first portion 3.
  • the entire shaft as described, formed by the first member 1 and the second member 3, 4 rotates about the axis of rotation A, being driven by a power output of the motor (not shown).
  • an axial cavity 5 is provided to receive a delivery controlling unit, generically indicated in 6, which is formed substantially with a wheel 7 and a pinion gear 8 integral with the wheel 7, through a spindle 9 housed in said axial cavity 5.
  • the unit 6 can slide in an axial direction, guided by the axial cavity 5 and a guide cylinder 11 integral with the unit 6, and it is returned to the operating position (which will be described hereinafter) by a return spring 10 abutting between the guide cylinder 11 and a plate 12 integral with the second portion 4 of the second shaft member and fixed thereto by means of screws 13.
  • the delivery controlling unit 6 can also rotate within the axial cavity 5 about the axis of rotation A, in order to control the adjustment of delivery, as will be described herein­after.
  • the unit 6 will be locked to the second shaft portion 4 by means of a locking pin 14 which makes the wheel 7 and the plate 12 rigidly connected. In the locking position the unit 6 will rotate the entire pump shaft as a single unit, in a position axially centered with respect to the axis of rotation. This feature is peculiar to the present invention.
  • a delivery adjusting unit is generically indicated with numeral 15 and comprises a cam 16 and an annular gear cap 17.
  • the cam 16 is pivotally mounted around the excentrical shaft portion 3 and has a geometric axis indicated with C, which will be hereinafter denomina­ted offset axis.
  • the annular gear cap 17 is integral with the cam 16, however its geometric axis, which is also its axis of rotation, coincides with the excentric geometric axis E of the excentric shaft portion 3.
  • the annular gear cap 17 is provided with an internal toothing in gear with the external toothing of the pinion 8.
  • An adjustment shim 18 separates the unit 15 from the first shaft member 1.
  • the unit 15, as as­sembled, will rotate about the axis of rotation A during the operation of the pump, so that the cam 16 is the excentric controlling the movable elements (pistons) of the pump, which are schematically indicated in 19, as a reciprocating box of the reciprocating unit for the movement of the pistons, not shown in the drawings.
  • the effective excentricity of the pump will be the distance from A to C, whereas the fixed excen­tricity of the shaft portion 3 (point E) is exactly one half of that. Consequently the path of the point C around the point A will describe a circle, indicated with T1 and drawn with a dot-and-dash line. It should be noted particularly that the oscillation range of the reciprocating unit 20 and pistons 21, 22 integral therewith, is equal to the diameter of the circle T1.
  • the variation from the maximum to the minimum excentricity is obtained by a 180° rotation of the cam 16 about the excentric shaft portion 3.
  • this 180° rotation will correspond to a 360° rotation of the wheel 7.
  • the wheel 7 will be provided with a mark related to an indexed scale on the plate 12 calibrated in function of the pump delivery. The arrangement of the indexes can obviously be inverted.
  • the pump according to the present invention is particularly suitable for the metering in agriculture of substances which are to be injected into the soil in precise doses and it shows the advantage of an extreme­ly simple handling to obtain an extremely precise effect.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
EP87830429A 1986-12-10 1987-12-03 Appareil de commande de débit pour des pompes à piston à débit variable Expired EP0271456B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT48726/86A IT1199304B (it) 1986-12-10 1986-12-10 Dispositivo di regolazione di portata per pompe a pistoni a portata variabile
IT4872686 1986-12-10

Publications (3)

Publication Number Publication Date
EP0271456A2 true EP0271456A2 (fr) 1988-06-15
EP0271456A3 EP0271456A3 (en) 1989-12-13
EP0271456B1 EP0271456B1 (fr) 1992-05-13

Family

ID=11268274

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87830429A Expired EP0271456B1 (fr) 1986-12-10 1987-12-03 Appareil de commande de débit pour des pompes à piston à débit variable

Country Status (2)

Country Link
EP (1) EP0271456B1 (fr)
IT (1) IT1199304B (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2004297297B2 (en) 2003-12-15 2011-04-14 Hydrostatic Design Technology Pty Ltd Hydraulic motor/pump

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD40427A (fr) *
US2592237A (en) * 1950-01-11 1952-04-08 Builders Iron Foundry Pump stroke adjusting device
DE887717C (de) * 1951-04-01 1953-08-27 Andreas Hofer Hochdruck Appbau Vorrichtung zur AEnderung des Kolbenhubes bei Kurbeltrieben
AT258067B (de) * 1965-03-10 1967-11-10 Gerhard Jesse Getriebe zur Umwandlung einer Drehbewegung in eine geradlinige Wechselbewegung mit einstellbarem Hub, insbesondere zum Antrieb von Dosierpumpen

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD40427A (fr) *
US2592237A (en) * 1950-01-11 1952-04-08 Builders Iron Foundry Pump stroke adjusting device
DE887717C (de) * 1951-04-01 1953-08-27 Andreas Hofer Hochdruck Appbau Vorrichtung zur AEnderung des Kolbenhubes bei Kurbeltrieben
AT258067B (de) * 1965-03-10 1967-11-10 Gerhard Jesse Getriebe zur Umwandlung einer Drehbewegung in eine geradlinige Wechselbewegung mit einstellbarem Hub, insbesondere zum Antrieb von Dosierpumpen

Also Published As

Publication number Publication date
IT8648726A0 (it) 1986-12-10
EP0271456A3 (en) 1989-12-13
EP0271456B1 (fr) 1992-05-13
IT1199304B (it) 1988-12-30

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