EP0203794A1 - Hydraulic RAM assembly - Google Patents

Hydraulic RAM assembly Download PDF

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Publication number
EP0203794A1
EP0203794A1 EP86303944A EP86303944A EP0203794A1 EP 0203794 A1 EP0203794 A1 EP 0203794A1 EP 86303944 A EP86303944 A EP 86303944A EP 86303944 A EP86303944 A EP 86303944A EP 0203794 A1 EP0203794 A1 EP 0203794A1
Authority
EP
European Patent Office
Prior art keywords
piston
ram
cylinder
extension
housing
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.)
Withdrawn
Application number
EP86303944A
Other languages
German (de)
French (fr)
Inventor
John Hugh Meaden
David Hobson
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.)
Davy Mckee Poole Ltd
Original Assignee
Davy Mckee Poole Ltd
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 Davy Mckee Poole Ltd filed Critical Davy Mckee Poole Ltd
Publication of EP0203794A1 publication Critical patent/EP0203794A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B31/00—Rolling stand structures; Mounting, adjusting, or interchanging rolls, roll mountings, or stand frames
    • B21B31/16—Adjusting or positioning rolls
    • B21B31/20—Adjusting or positioning rolls by moving rolls perpendicularly to roll axis
    • B21B31/32—Adjusting or positioning rolls by moving rolls perpendicularly to roll axis by liquid pressure, e.g. hydromechanical adjusting
    • 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
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/028—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the actuating force
    • F15B11/036—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the actuating force by means of servomotors having a plurality of working chambers
    • F15B11/0365—Tandem constructions
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20538—Type of pump constant capacity
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/305—Directional control characterised by the type of valves
    • F15B2211/30525—Directional control valves, e.g. 4/3-directional control valve
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/30—Directional control
    • F15B2211/32—Directional control characterised by the type of actuation
    • F15B2211/327—Directional control characterised by the type of actuation electrically or electronically
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6336—Electronic controllers using input signals representing a state of the output member, e.g. position, speed or acceleration
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7051—Linear output members
    • F15B2211/7055—Linear output members having more than two chambers
    • F15B2211/7056—Tandem cylinders
    • 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
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/76—Control of force or torque of the output member

Definitions

  • This invention relates to an assembly of two hydraulic rams.
  • the present invention relates to an assembly of a first ram comprising a housing defining an open-ended cylinder, a piston displaceable in the cylinder and means for introducing fluid under pressure into the cylinder to displace the piston in the direction towards the open end of the cylinder; and a second ram comprising a housing defining a cylinder and a piston displaceable in the cylinder, characterised in that the cylinder of the second ram is in communication with the cylinder of the first ram through an opening in the housing of the first ram which is opposite the open end of the cylinder, means for introducing fluid under pressure into the cylinder of the second ram to displace the piston in the direction towards the opening and the piston of the second ram having an extension which projects through the opening in the housing and is engageable with the piston of the first ram.
  • the engaging surfaces of the extension and the piston of the first ram are such as to permit limited relative inclination between the axis of the extension and the axis of the cylinder of the first ram.
  • the first ram only is employed or the two rams can be operated together.
  • the extension of the piston in the second ram is engageable with the piston of the first ram, but is not permanently connected thereto, when hydraulic fluid is introduced into the cylinder of the first ram, it acts against the full surface of the piston therein and it also acts against the extension to displace the piston in the second ram in the direction to separate the extension from the piston in the first ram.
  • only one seal i.e. that between the piston of that ram and the cylinder wall, is employed. This permits slight tilting between the piston and the cylinder wall.
  • the ram assembly is used to displace a chock 1 of a rolling mill stand relative to a fixed housing 2 of the mill stand.
  • An assembly according to the present invention is located in a recess 3 formed in the housing.
  • the assembly consists of a housing 4 having a side wall 5 and an end wall 6 and together they define a cylinder 7 which is open-ended.
  • a piston 8 having a wall seal 9 is displaceable in the cylinder 7 to constitute a ram.
  • a further housing 10 which has a slide wall 11 and an end wall 12 and together with the end wall 6 of the first ram they define a cylinder 13.
  • a piston 15 is displaceable in the cylinder 13 to constitute a ram and there is a seal 16 between the piston 15 and the wall of the cylinder.
  • the piston has an extension 17 which projects through an opening 18 in the end wall 6 of the housing 4 and there is a seal 19 between the extension and the wall of the opening.
  • the lower end of the extension projects into the cylinder 7 and is engageable with the adjacent surface of the piston 8. It is preferable for the end face of the extension 17 and the adjacent face of the piston 8 to be of convex and concave form, respectively, so that limited inclination can take place between the piston 8 and the extension and there can be relative inclination between the longitudinal axis of the extension and that of the cylinder 7.
  • the part of the cylinder 13 which is between the piston 15 and the wall 6 of the housing 4 is kept open by way of a permanent connection 20 to drain.
  • the part of the cylinder 13 above the piston 15 is connected by a fluid line to a port on a solenoid valve 21 and the cylinder 7 is also connected to a port on the solenoid valve 21 by a fluid line.
  • the solenoid valve has a connection from a controllable hydraulic source 22 directly to the cylinder 7 and the part of the cylinder 13 above the piston 15 is connected through the solenoid valve to drain.
  • transducers can be employed to give an indication of the relative positions of the pistons with respect to the fixed mill housings 2.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Actuator (AREA)

Abstract

A hydraulic ram assembly capable of providing a force varying over a wide range has a first ram with a fixed cylinder and a movable piston which is capable of supplying a force at the lower end of the range and a second ram with a fixed cylinder and a piston which is movable into engagement with the piston of the first ram to assist the first piston to thereby provide an increased load.

Description

  • This invention relates to an assembly of two hydraulic rams.
  • In certain industrial applications, it is desirable for a hydraulic ram assembly to provide a force varying over a very wide range. It is very difficult to design a single hydraulic ram which is capable of acting accurately and efficiently over a wide range of forces.
  • Accordingly, the present invention relates to an assembly of a first ram comprising a housing defining an open-ended cylinder, a piston displaceable in the cylinder and means for introducing fluid under pressure into the cylinder to displace the piston in the direction towards the open end of the cylinder; and a second ram comprising a housing defining a cylinder and a piston displaceable in the cylinder, characterised in that the cylinder of the second ram is in communication with the cylinder of the first ram through an opening in the housing of the first ram which is opposite the open end of the cylinder, means for introducing fluid under pressure into the cylinder of the second ram to displace the piston in the direction towards the opening and the piston of the second ram having an extension which projects through the opening in the housing and is engageable with the piston of the first ram.
  • Preferably, the engaging surfaces of the extension and the piston of the first ram are such as to permit limited relative inclination between the axis of the extension and the axis of the cylinder of the first ram.
  • Depending on the force which is to be developed, either the first ram only is employed or the two rams can be operated together.
  • Since the extension of the piston in the second ram is engageable with the piston of the first ram, but is not permanently connected thereto, when hydraulic fluid is introduced into the cylinder of the first ram, it acts against the full surface of the piston therein and it also acts against the extension to displace the piston in the second ram in the direction to separate the extension from the piston in the first ram. When only the first ram is being used, only one seal, i.e. that between the piston of that ram and the cylinder wall, is employed. This permits slight tilting between the piston and the cylinder wall.
  • With both cylinders in operation, there are three seals in use, the seals being positioned between the pistons and the walls of their respective cylinders and between the extension and the housing of the first ram.
  • In order that the invention may be more readily understood, it will now be described, by way of example only with reference to the accompanying drawing which is a diagrammatic section of a ram assembly according to the present invention.
  • In the arrangement shown in the figure, the ram assembly is used to displace a chock 1 of a rolling mill stand relative to a fixed housing 2 of the mill stand. An assembly according to the present invention is located in a recess 3 formed in the housing. The assembly consists of a housing 4 having a side wall 5 and an end wall 6 and together they define a cylinder 7 which is open-ended. A piston 8 having a wall seal 9 is displaceable in the cylinder 7 to constitute a ram.
  • Separate from, but mounted on this housing 4, there is a further housing 10 which has a slide wall 11 and an end wall 12 and together with the end wall 6 of the first ram they define a cylinder 13. A piston 15 is displaceable in the cylinder 13 to constitute a ram and there is a seal 16 between the piston 15 and the wall of the cylinder. The piston has an extension 17 which projects through an opening 18 in the end wall 6 of the housing 4 and there is a seal 19 between the extension and the wall of the opening.
  • The lower end of the extension projects into the cylinder 7 and is engageable with the adjacent surface of the piston 8. It is preferable for the end face of the extension 17 and the adjacent face of the piston 8 to be of convex and concave form, respectively, so that limited inclination can take place between the piston 8 and the extension and there can be relative inclination between the longitudinal axis of the extension and that of the cylinder 7.
  • The part of the cylinder 13 which is between the piston 15 and the wall 6 of the housing 4 is kept open by way of a permanent connection 20 to drain. The part of the cylinder 13 above the piston 15 is connected by a fluid line to a port on a solenoid valve 21 and the cylinder 7 is also connected to a port on the solenoid valve 21 by a fluid line. In the arrangement shown, the solenoid valve has a connection from a controllable hydraulic source 22 directly to the cylinder 7 and the part of the cylinder 13 above the piston 15 is connected through the solenoid valve to drain. In this way, the hydraulic fluid supplied to the cylinder 7 causes a force to be applied to the piston 8, and the piston 15 is forced upwardly to the top of its cylinder so that it is not in contact with the piston 8 by the force of the fluid acting on the extension 17. Thus, the force of the fluid in the cylinder 7 acts over the entire surface of the piston 8. When the solenoid valve 21 is connected in its opposite operating position, fluid under pressure is supplied to the cylinder 7 and to the cylinder 13 above the piston 15 and, hence, the extension 17 is forced downwardly into engagement with the piston 8 to provide a combined force acting on the chock 1. It will be seen, therefore, that either the ram consisting of the piston 8 in the cylinder 7 can be brought into operation on its own, or it can be in operation along with the piston 15 in the cylinder 13, thus providing a much greater force on the chock 1.
  • Even when both rams are in operation, the extension 17 can be inclined slightly with respect to the axis of the piston 8. When both rams are in . operation, there are three seals in use, but the seal friction is not so critical when large operating forces are being produced.
  • Various forms of transducers (not shown) can be employed to give an indication of the relative positions of the pistons with respect to the fixed mill housings 2.

Claims (5)

1. An assembly of a first ram comprising a housing (4) defining an open-ended cylinder (7), a piston (8) displaceable in the cylinder and means for introducing fluid under pressure into the cylinder to displace the piston in the direction towards the open end of the cylinder;
and a second ram comprising a housing (10) defining a cylinder (13) and a piston (15) displaceable in the cylinder, characterised in that the cylinder of the second ram is in communication with the cylinder of the first ram through an opening (18) in the housing (4) of the first ram which is opposite the open end of the cylinder, means for introducing fluid under pressure into the cylinder of the second ram to displace the piston in the direction towards the opening and the piston of the second ram having an extension (17) which projects through the opening in the housing and is engageable with the piston (8) of the first ram.
2. An assembly as claimed in claim 1, characterised in that the piston (8) of the first ram is provided with one peripheral seal (9) which permits limited tilting of the piston relative to the cylinder (7).
3. An assembly as claimed in claim 1 or 2, characterised in that the surface of the extension (17) which is engageable with the piston (8) of the first ram is of convex form and the corresponding surface of the piston (8) is of concave form thereby permitting limited inclination between the axis of the extension and that of the piston.
4. An assembly as claimed in claim 1, 2 or 3, characterised in that it includes control valve means (21, 22) which permits fluid to be supplied to the cylinder of the first ram and optionally to the cylinder of the second ram.
5. An assembly as claimed in claim 2, characterised in that there is one peripheral seal (19) between the extension and the wall of the housing which defines the opening and one peripheral seal (16) on the piston of the second ram.
EP86303944A 1985-05-29 1986-05-23 Hydraulic RAM assembly Withdrawn EP0203794A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB858513553A GB8513553D0 (en) 1985-05-29 1985-05-29 Hydraulic ram assembly
GB8513553 1985-05-29

Publications (1)

Publication Number Publication Date
EP0203794A1 true EP0203794A1 (en) 1986-12-03

Family

ID=10579855

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86303944A Withdrawn EP0203794A1 (en) 1985-05-29 1986-05-23 Hydraulic RAM assembly

Country Status (2)

Country Link
EP (1) EP0203794A1 (en)
GB (1) GB8513553D0 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4108220C2 (en) * 1991-03-14 2003-04-17 Festo Ag & Co Piston-cylinder arrangement
EP1459813A2 (en) * 2003-03-21 2004-09-22 Sundwig GmbH Adjusting cylinder for rolling mills for rolling of steel or non-ferrous metall
AT500476A1 (en) * 2004-07-02 2006-01-15 Voest Alpine Ind Anlagen PRESSURE TRANSMISSION PRESSURE CYLINDER

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3053294A (en) * 1959-01-24 1962-09-11 Lindberg Hans Fluid pressure operated mechanism for actuating the debarking tools of a debarking machine of the rotaryring type
GB944223A (en) * 1960-05-18 1963-12-11 Dewandre Co Ltd C Improvements in or relating to air pressure operated apparatus
FR1602570A (en) * 1967-12-22 1970-12-28
GB1600733A (en) * 1978-02-27 1981-10-21 Midgley A C Coining presses

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3053294A (en) * 1959-01-24 1962-09-11 Lindberg Hans Fluid pressure operated mechanism for actuating the debarking tools of a debarking machine of the rotaryring type
GB944223A (en) * 1960-05-18 1963-12-11 Dewandre Co Ltd C Improvements in or relating to air pressure operated apparatus
FR1602570A (en) * 1967-12-22 1970-12-28
GB1600733A (en) * 1978-02-27 1981-10-21 Midgley A C Coining presses

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4108220C2 (en) * 1991-03-14 2003-04-17 Festo Ag & Co Piston-cylinder arrangement
EP1459813A2 (en) * 2003-03-21 2004-09-22 Sundwig GmbH Adjusting cylinder for rolling mills for rolling of steel or non-ferrous metall
EP1459813A3 (en) * 2003-03-21 2005-06-15 Sundwig GmbH Adjusting cylinder for rolling mills for rolling of steel or non-ferrous metall
AT500476A1 (en) * 2004-07-02 2006-01-15 Voest Alpine Ind Anlagen PRESSURE TRANSMISSION PRESSURE CYLINDER
AT500476B1 (en) * 2004-07-02 2006-07-15 Voest Alpine Ind Anlagen PRESSURE TRANSMISSION PRESSURE CYLINDER

Also Published As

Publication number Publication date
GB8513553D0 (en) 1985-07-03

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Inventor name: HOBSON, DAVID

Inventor name: MEADEN, JOHN HUGH