US3872732A - Device for moving the piston rod of a piston pump - Google Patents

Device for moving the piston rod of a piston pump Download PDF

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Publication number
US3872732A
US3872732A US446744A US44674474A US3872732A US 3872732 A US3872732 A US 3872732A US 446744 A US446744 A US 446744A US 44674474 A US44674474 A US 44674474A US 3872732 A US3872732 A US 3872732A
Authority
US
United States
Prior art keywords
shaft
disc
piston
rod
driving
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
US446744A
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English (en)
Inventor
Heinz Dzaack
Hans Krook
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.)
Pfizer Health AB
Original Assignee
LKB Produkter AB
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 LKB Produkter AB filed Critical LKB Produkter AB
Application granted granted Critical
Publication of US3872732A publication Critical patent/US3872732A/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • F04B9/00—Piston machines or pumps characterised by the driving or driven means to or from their working members
    • F04B9/02—Piston machines or pumps characterised by the driving or driven means to or from their working members the means being mechanical
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T74/00—Machine element or mechanism
    • Y10T74/18—Mechanical movements
    • Y10T74/18056—Rotary to or from reciprocating or oscillating

Definitions

  • ABSTRACT A device for moving the piston rod of a pump in reversible longitudinal directions consists of a reversibly rotatable shaft having a radially projecting driving member secured thereon; the shaft also rotatable carries a connecting member and a driven member, the latter being connected to the piston rod; the rotation of the shaft being transmitted by the driving member to the driven member through the connecting member by springs which equalize the forces regardless of the length of the stroke of the piston rod.
  • the present invention refers to a device for moving of the piston rod of a piston pump, for instance for use in diluting different liquid volumes in clinical laboratory investigations.
  • the dilution consists in connecting a reagent vessel to a piston pump which via a valve sucks a well defined quantity of the reagent into the pump cylinder and then sprays the reagent into the sample vessel.
  • the piston is thereby usually driven from a shank excentrically journalled on a rotating disc, the shank being connected to the piston rod.
  • a smooth dilution will be obtained, since the velocity of the piston will approximately follow a sine curve.
  • the drawbacks of such a device are however that it is difficult to obtain small diluting volumes of high accuracy and furthermore the diluting time will be the same for all volumes.
  • the driving disc has to be stopped at the ends of the piston stroke in order to make it possible to switch the valve from intake to spray position or vice versa.
  • FIG. 1 is a side view of a device according to the invention and FIG. 2 is a cross-section along the driving axis at the device shown in FIG. 1.
  • reference 1 denotes a driving shaft, which is alternatively rotated in opposite directions from a driving means not shown in the figures.
  • a driving disc 2 To the shaft there is atttached a driving disc 2 by means of a connecting pin 3.
  • a connecting disc 7 is journalled on the shaft l.
  • the driving disc 2 and the connecting disc 7 are resiliently engaged to each other by means of a draw spring 12, having one end connected to the spring mounting 13 of the disc 7 and its other end connected to the spring carrier 14 of the disc 2.
  • a shank 15 of the disc 7 is pressed against a bent portion 16 of the disc 2.
  • the shaft is further provided with a driven plate 9 journalled on the axis and provided with a bent portion 9a which is pressed against the shank 15 of the connecting plate 7 by means of a spring 8 having one end connected to a spring pin 10 of the driven plate 9 and the other end connected to a stationary frame 11. Furthermore a spring 17 is connected between the driving disc 2 and the frame 11, the spring force of the spring 17 affecting the device in a direction opposite to the direction of the force from the spring 8.
  • the driven disc 9 is provided with a protruding forkshaped part 18 which engages a roll l9'journalled on a shaft 20 attached to a rod 21 which is axially movable within two guidings 22 and 23 respectively.
  • the rod 21 is provided with an extension arm 24 to which the piston rod (not shown) can be connected.
  • the displacement of the rod 20 is limited by two screws 25 and 26, the screw 26 in practice consisting of a number of stop pins at different levels so as to make it possible to obtain different strokes of the rod 21.
  • the device described above operates as follows. If it is assumed that the rod 21 is in the position shown in FIG. 1 and the shaft 1 is driven in the direction of the arrow A, the driving disc 2 which is attached to the shaft will also turn and consequently also the connecting disc 7 and its shaft 15. When the shaft 15 is moving in the direction of the arrow A, the spring 8 will move the driven disc 9 in the direction of rotation ofthe shaft 1 and the spring 17 will be stretched. The rod 21 will thus move downwards till the arm 24 meets the screw 26. At this point the driven plate 10 will stop whereas the driving plate 2 and the connecting plate 7 will move on till the direction of rotation of the shaft 1 is re versed. At this point of time the bent portion 9a of the driven plate 9 has been disengaged from the shank 15 of the disc 7.
  • a further advantage is that the shaft 1 continues its rotation after the rod 21 has stopped and this movement of the axis could be used for switching the valves in the pump, e.g., for switching the valve to the intake position after a spraying cycle but before the axis is stopped in the position where the direction of rotation is reversed.
  • This is very advantageous in such devices where the liquid storing vessel is directly connected to the pump and the pump is moved from the frame together with this vessel. If the valve is not switched there is otherwise the risk that when storing the pump and vessel,' liquid is sprayed from the pump, e.g., due to changes of temperature or minor movements of the piston.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
US446744A 1973-02-28 1974-02-28 Device for moving the piston rod of a piston pump Expired - Lifetime US3872732A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE7302785A SE370440B (it) 1973-02-28 1973-02-28

Publications (1)

Publication Number Publication Date
US3872732A true US3872732A (en) 1975-03-25

Family

ID=20316756

Family Applications (1)

Application Number Title Priority Date Filing Date
US446744A Expired - Lifetime US3872732A (en) 1973-02-28 1974-02-28 Device for moving the piston rod of a piston pump

Country Status (5)

Country Link
US (1) US3872732A (it)
JP (1) JPS5840035B2 (it)
FR (1) FR2219318B1 (it)
GB (1) GB1437564A (it)
SE (1) SE370440B (it)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI820432L (fi) * 1982-02-10 1983-08-11 Rosenlew Ab Oy W Manovreringsanordning foer endoseringspump, speciellt foer en faergnyanseringsmaskin

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2267409A (en) * 1941-10-02 1941-12-23 Alvin A Massini Cam
US2591216A (en) * 1944-11-28 1952-04-01 United States Steel Corp Valve operating mechanism
US3340743A (en) * 1964-12-28 1967-09-12 Sterling O Stageberg Variable speed power transmission with flexible band and drive link
US3490309A (en) * 1967-09-27 1970-01-20 Peritus Ab Toggle mechanism

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2267409A (en) * 1941-10-02 1941-12-23 Alvin A Massini Cam
US2591216A (en) * 1944-11-28 1952-04-01 United States Steel Corp Valve operating mechanism
US3340743A (en) * 1964-12-28 1967-09-12 Sterling O Stageberg Variable speed power transmission with flexible band and drive link
US3490309A (en) * 1967-09-27 1970-01-20 Peritus Ab Toggle mechanism

Also Published As

Publication number Publication date
JPS5840035B2 (ja) 1983-09-02
DE2407964B2 (de) 1976-03-11
FR2219318A1 (it) 1974-09-20
SE370440B (it) 1974-10-14
DE2407964A1 (de) 1974-09-05
FR2219318B1 (it) 1978-01-06
JPS507104A (it) 1975-01-24
GB1437564A (en) 1976-05-26

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