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WO2019158989A1 - Apparatus for regulating the stroke of double-acting hydraulic actuators - Google Patents

Apparatus for regulating the stroke of double-acting hydraulic actuators Download PDF

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Publication number
WO2019158989A1
WO2019158989A1 PCT/IB2019/000015 IB2019000015W WO2019158989A1 WO 2019158989 A1 WO2019158989 A1 WO 2019158989A1 IB 2019000015 W IB2019000015 W IB 2019000015W WO 2019158989 A1 WO2019158989 A1 WO 2019158989A1
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WO
WIPO (PCT)
Prior art keywords
pressure
hydraulic
valve
stem side
double
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.)
Ceased
Application number
PCT/IB2019/000015
Other languages
French (fr)
Inventor
Riccardo Magni
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.)
Magni Telescopic Handlers SRL
Original Assignee
Magni Telescopic Handlers SRL
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 Magni Telescopic Handlers SRL filed Critical Magni Telescopic Handlers SRL
Priority to EP19712013.2A priority Critical patent/EP3752739B1/en
Publication of WO2019158989A1 publication Critical patent/WO2019158989A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • 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
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/044—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the return line, i.e. "meter out"
    • F15B11/0445—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed by means in the return line, i.e. "meter out" with counterbalance valves, e.g. to prevent overrunning or for braking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/065—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks non-masted
    • B66F9/0655—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks non-masted with a telescopic boom
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/20—Means for actuating or controlling masts, platforms, or forks
    • B66F9/22—Hydraulic devices or systems
    • 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
    • F15B11/16—Servomotor systems without provision for follow-up action; Circuits therefor with two or more servomotors
    • F15B11/22—Synchronisation of the movement of two or more servomotors
    • 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
    • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
    • F15B20/005—Leakage; Spillage; Hose burst
    • 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
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50545—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using braking valves to maintain a back pressure
    • 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
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50554—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure downstream of the pressure control means, e.g. pressure reducing 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
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50563—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure
    • F15B2211/50581—Pressure control characterised by the type of pressure control means the pressure control means controlling a differential pressure using counterbalance valves
    • 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
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5153—Pressure control characterised by the connections of the pressure control means in the circuit being connected to an output member and a 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
    • F15B2211/50—Pressure control
    • F15B2211/575—Pilot pressure control
    • 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
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6313—Electronic controllers using input signals representing a pressure the pressure being a load pressure
    • 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
    • F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
    • F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means
    • 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
    • F15B2211/7053—Double-acting output members
    • 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
    • F15B2211/71—Multiple output members, e.g. multiple hydraulic motors or cylinders
    • F15B2211/7114—Multiple output members, e.g. multiple hydraulic motors or cylinders with direct connection between the chambers of different actuators
    • F15B2211/7128—Multiple output members, e.g. multiple hydraulic motors or cylinders with direct connection between the chambers of different actuators the chambers being connected in parallel
    • 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
    • F15B2211/78—Control of multiple output members
    • F15B2211/782—Concurrent control, e.g. synchronisation of two or more actuators
    • 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
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/86—Control during or prevention of abnormal conditions
    • F15B2211/8606—Control during or prevention of abnormal conditions the abnormal condition being a shock
    • 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
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/86—Control during or prevention of abnormal conditions
    • F15B2211/8613—Control during or prevention of abnormal conditions the abnormal condition being oscillations
    • 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
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/86—Control during or prevention of abnormal conditions
    • F15B2211/863—Control during or prevention of abnormal conditions the abnormal condition being a hydraulic or pneumatic failure
    • F15B2211/8636—Circuit failure, e.g. valve or hose failure

Definitions

  • the object of the present invention is an apparatus for regulating the stroke of double-acting hydraulic actuators for the hydraulic actuation of manoeuvring means of operating machines.
  • each of these hydraulic actuators consisting of double-acting hydraulic cylinders
  • a hydraulic over-center valve is normally provided, through which pressure is given to the stem side of the cylinder and the bottom side is opened in order to lower the arm in safety.
  • the known technique has the disadvantage of causing a certain functional and constructive complication in the bottom sides. This is in particular evident when two or more hydraulic actuators work together to hydraulically actuate operating machine parts.
  • Object of the present invention is to limit the disadvantages and drawbacks of the prior art while maintaining high safety standards, in accordance with what is described, illustrated and claimed below.
  • Another object of the invention is to synchronize the pressures and make them uniform at every point of the circuit of two or more hydraulic actuators that collaborate together coupled to the hydraulic operation of manoeuvring and lifting members mounted onto operating machines.
  • An advantage of the invention is that it has a relatively simple structure in terms of circuitry.
  • FIG. 1 shows a schematic side view in vertical elevation of a self-propelled operating machine equipped with a manoeuvring device consisting of a telescopic arm for the hydraulic lifting of which a double-acting hydraulic actuator or cylinder is used;
  • FIG. 2 shows a schematic hydraulic layout of a first embodiment of the invention
  • FIG. 3 shows a schematic hydraulic layout of a second embodiment of the invention
  • numeral 1 indicates as a whole a self-propelled operating machine, made mobile on wheels 2, which is equipped with a manoeuvring member at the top, consisting of a telescopic hoisting arm 3, the movement of which is carried out by means of a double acting hydraulic actuator 4.
  • the hydraulic actuator 4 is nothing more than a double-acting hydraulic cylinder which is hinged with its bottom side 5 to the frame of the self-propelled operating machine 4 and, with its stem, to the telescopic hoisting arm 3.
  • the hydraulic actuator or double-acting hydraulic cylinder 4 is fed by a hydraulic control circuit, which is connected to a hydraulic distributor 7, from which a supply line 8 for feeding the bottom side 5 and a supply line 9 for feeding the stem side 6 originate.
  • a shut-off and regulation valve 10 is provided along the supply line 8 of the bottom side 5, with the function of intercepting and regulating the flow of fluid out coming, the valve being controlled by an electronic regulation valve 11.
  • This latter is operated by the signal originating from a pressure transducer 12 as a function of a pressure value measured at the stem side 6.
  • the electronic regulation valve 11 is adjusted to intervene on the shut-off valve 10 in order to control and increase its opening when the pressure of the stem side 6, reported by the pressure transducer 12, reaches a preset minimum value and to open the valve up to reaching a pressure at stem side 6 having a predetermined value.
  • valve 10 If the pressure on the stem side falls down, the opening of valve 10, controlled by the electronic control valve 11 , is reduced (when the movement stops it is completely closed), so as to maintain the pressure on the stem side 6 within a pre-established "balancing" pressure range.
  • the electronic regulation valve 11 is controlled by the value of the pressure on the stem side 6 through interposition of a pressure reducing valve 13.
  • starting operation of the electronic control valve 11 is determined by its necessary adjustment, with which the minimum and maximum values that define the range of action of the "balancing" pressure have been set in advance. Therefore, during the lowering step, i.e. the return of the stem, the actual pressure, as reduced by the reducing valve 13, which is detected at the rod side 6 of the double-acting hydraulic cylinder 4, operates the shut-off valve 10.
  • shut-off valve 10 is operated hydraulically through the interposition of the pressure reducing valve 13 and is modulated by the electronic control valve 11 which is a proportional valve.
  • the combination of the pressure reducing valve 13 and the electronic proportional control valve 1 1 is indicated by the acronym EVP, and hydraulically controls the shut-off valve 10 according to the methods described above.
  • the action of the EVP system thus avoids the inconvenience of possible repeated closing of the shut-off valve 10, which would cause a kind of unwanted "hopping" of the telescopic hoisting arm 3 and the load it supports, thus allowing a continuous and shock-free lowering of the piston stem of the hydraulic actuator consisting of the double acting hydraulic cylinder 4.
  • the pressure on the stem side may decrease 6, which would cause the electronic control valve 11 to come into operation, which would command the shut-off valve 10 to reduce its opening, in order to keep the pressure on the stem side 6 within a predetermined minimum and maximum limit.
  • shut-off valve 10 does not open mechanically.
  • the movement of the telescopic hoisting arm 3 is carried out by means of two double-acting hydraulic actuators or hydraulic cylinders 4 equal to each other, which work together in conjunction with the hydraulic operation of the telescopic hoisting arm 3, both on lifting and lowering.
  • Each double acting hydraulic actuator or hydraulic cylinder 4 is served by a hydraulic control circuit, which is connected to the same hydraulic distributor 7 from which, for each of them, a supply line 8 for feeding the bottom side 5 and a supply line 9 for feeding the stem side 6 originate.
  • shut-off valve 10 On each of the supply lines 8 to the bottom side 5 there is a shut-off valve 10 with the function of intercepting and regulating the flow coming out of the relative bottom side 5.
  • Each double acting hydraulic actuator or hydraulic cylinder 4 is fed by a hydraulic control circuit, connected to the same hydraulic distributor 7 from which, for each double-acting hydraulic actuator or hydraulic cylinder 4, the supply line 8 for feeding the bottom side 5 and supply line 9 for feeding the stem side 6 originate, as previously mentioned.
  • An electronic regulation valve 11 is operated by the signal originated by a pressure transducer 12 in accordance with a pressure value detected at the stem side 6 of the double-acting hydraulic actuators or hydraulic cylinders 4.
  • the electronic regulation valve 11 is adjusted to intervene on the shut-off valves 10 in order to control and increase their openings when the pressure of the stem side 6, reported by the pressure transducer 12, reaches a preset minimum value and to open the valves up to reaching pressures at stem side 6 having a predetermined value.
  • valve 10 If the pressure on the stem side falls down, the opening of valve 10, controlled by the electronic control valve 11 , is reduced (when the movement stops it is completely closed), so as to maintain the pressure on the stem side (6) within a pre-established "balancing" pressure range.
  • the electronic regulation valve 11 is adjusted to intervene on the shut-off valves 10 in order to control and increase their openings when the pressure of the stem side 6, reported by the pressure transducer 12, reaches a pre-set minimum threshold.
  • valves 10 controlled by the electronic control valve 11 , are reduced (when the movement stops they are completely closed), so as to maintain the pressure on the stem side within a pre-established "balancing" pressure range.
  • the electronic regulation valve 11 is controlled by the value of the pressure on the stem side 6 through interposition of a pressure reducing valve 13.
  • the electronic regulation valve 11 acts on the shutoff valves 10 so as to gradually increase their opening starting when the pressure at the stem side 6 reaches a preset minimum threshold, and to reduce, also gradually, the opening in case the pressure on the stem side is reduced, so as to maintain on the stem side a pre-set so called pressure "balancing" value.
  • starting operation of the electronic control valve 11 is determined by its necessary adjustment, with which the minimum and maximum values that define the range of action of the "balancing" pressure have been set in advance.
  • each shut-off valve 10 is operated by the value of the pressure at the side of the stem 6 through the interposition of a pressure reducing valve 13 and is modulated by the electronic control valve 11.
  • connection 16 has been introduced between the chambers at the bottom sides 5 and a similar connection 17 has been inserted between the two chambers at the stem sides 6, which ensures stability and uniformity of pressures within the two chambers.
  • the electronic regulation valve 11 operates on both shut-off valves 10 in accordance with the methods previously illustrated, carrying out gradual interventions, without abrupt movements or shocks.
  • Numeral 14 indicates the driving line connecting the second shut-off valve 10, operating on the bottom side 6, to the electronic regulation valve 11 of the second double-acting hydraulic actuator or hydraulic cylinder 4.
  • a parachute valve 15 is arranged and operates along the bottom side balancing line 16 of the two double-acting hydraulic actuators or hydraulic cylinders 4.
  • the parachute valves 15 operate in the same way on the bottom sides of the double acting hydraulic actuators or hydraulic cylinders 4, are connected to each other by a connection 16 and have the task of preventing both chambers from emptying in the event of a breakage of a pipe.
  • the modes of operation are basically those of the first illustrated embodiment characterized by the presence of a single double acting hydraulic actuator or hydraulic cylinder.

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  • Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Civil Engineering (AREA)
  • Geology (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Actuator (AREA)

Abstract

The invention relates to an apparatus for regulating the stroke of double-acting hydraulic actuators of the type used for hydraulic actuation of manoeuvring members of operating machines, in which the single double-acting hydraulic actuator (4) is powered by a hydraulic control circuit, controlled by a hydraulic distributor (7) from which a supply line (8) originates for feeding the bottom side (5) and a supply line (9) originates for feeding the stem side (6). A shut-off valve (10) is provided on the supply line (8) to the bottom side (5) with the task of intercepting and regulating the outlet flow. The latter is controlled by an electronic regulation valve (11) operated by the signal originated by a pressure transducer (12) that detects the pressure value at the stem side (6). The electronic regulation valve (11) is adjusted to intervene on the shut-off valve (10) in order to control and increase its opening when the pressure of the stem side (6), reported by the pressure transducer (12), reaches a preset minimum value and to open the valve up to reaching a pressure at stem side (6) having a pre-set value, so as to maintain the pressure at the stem side (6) within a pre-established "balance" pressure range. The shut-off valve (10) is hydraulically operated by the pressure value at the stem side (6) through interposition of a pressure reducing valve (13) and modulated by an electronic regulation valve (11).

Description

APPARATUS FOR REGULATING THE STROKE OF DOUBLE-ACTING
HYDRAULIC ACTUATORS
DESCRIPTION OF THE INVENTION
The object of the present invention is an apparatus for regulating the stroke of double-acting hydraulic actuators for the hydraulic actuation of manoeuvring means of operating machines.
In the prior art, each of these hydraulic actuators, consisting of double-acting hydraulic cylinders, is individually equipped, for safety reasons, with its own shut-off valve, which is fastened to the cylinder itself with the specific task of ensuring, in the event that a hydraulic hose gets broken, the sealing of the cylinder, preventing it from emptying and dropping the operating element and the load applied thereto.
To achieve a certain precision and linearity in the descent of an device such as a hoisting arm of an operating machine driven by a double-acting cylinder, a hydraulic over-center valve is normally provided, through which pressure is given to the stem side of the cylinder and the bottom side is opened in order to lower the arm in safety. With this solution, however, essentially because it uses a hydraulic-mechanical valve, at the time of opening during the descent phase, a more or less abrupt movement occurs, depending on the settings, that is gradually more extended as the loads involved increase. Furthermore, especially for large operating machines using large hoisting arms operated by big cylinders and subjected to their own weight and that of the heavy loads, an actual hopping is caused during lowering due to occurrence of a sudden drop in pressure on the stem side (because the hydraulic liquid supplied to the chamber on the stem side by the distributor is insufficient to fill the volume necessary to keep the chamber under pressure) and this causes the momentary closure of the shut-off valve with consequent stopping of the arm lowering. Lowering, however, resumes immediately after giving rise to a succession of operation steps in rapid succession of the shut-off valve (hopping) until the cylinder on the stem side is restored to operating pressure.
To solve this problem, the use of a hydraulic accumulator is known, which is specifically designed to feed the chamber on the stem side and keep it under pressure throughout the lowering stroke.
However, the known technique has the disadvantage of causing a certain functional and constructive complication in the bottom sides. This is in particular evident when two or more hydraulic actuators work together to hydraulically actuate operating machine parts.
Object of the present invention is to limit the disadvantages and drawbacks of the prior art while maintaining high safety standards, in accordance with what is described, illustrated and claimed below. Another object of the invention is to synchronize the pressures and make them uniform at every point of the circuit of two or more hydraulic actuators that collaborate together coupled to the hydraulic operation of manoeuvring and lifting members mounted onto operating machines. An advantage of the invention is that it has a relatively simple structure in terms of circuitry.
Additional features and advantages will result more evident from the following detailed description of some preferred, but not exclusive, embodiments of the invention, herein illustrated by way of example only in the attached figures, in which: ,
- Figure 1 shows a schematic side view in vertical elevation of a self-propelled operating machine equipped with a manoeuvring device consisting of a telescopic arm for the hydraulic lifting of which a double-acting hydraulic actuator or cylinder is used;
- Figure 2 shows a schematic hydraulic layout of a first embodiment of the invention;
- Figure 3 shows a schematic hydraulic layout of a second embodiment of the invention;
With reference to the above mentioned Figures, numeral 1 indicates as a whole a self-propelled operating machine, made mobile on wheels 2, which is equipped with a manoeuvring member at the top, consisting of a telescopic hoisting arm 3, the movement of which is carried out by means of a double acting hydraulic actuator 4.
The hydraulic actuator 4 is nothing more than a double-acting hydraulic cylinder which is hinged with its bottom side 5 to the frame of the self-propelled operating machine 4 and, with its stem, to the telescopic hoisting arm 3.
The hydraulic actuator or double-acting hydraulic cylinder 4 is fed by a hydraulic control circuit, which is connected to a hydraulic distributor 7, from which a supply line 8 for feeding the bottom side 5 and a supply line 9 for feeding the stem side 6 originate.
A shut-off and regulation valve 10 is provided along the supply line 8 of the bottom side 5, with the function of intercepting and regulating the flow of fluid out coming, the valve being controlled by an electronic regulation valve 11.
This latter is operated by the signal originating from a pressure transducer 12 as a function of a pressure value measured at the stem side 6.
The electronic regulation valve 11 is adjusted to intervene on the shut-off valve 10 in order to control and increase its opening when the pressure of the stem side 6, reported by the pressure transducer 12, reaches a preset minimum value and to open the valve up to reaching a pressure at stem side 6 having a predetermined value.
If the pressure on the stem side falls down, the opening of valve 10, controlled by the electronic control valve 11 , is reduced (when the movement stops it is completely closed), so as to maintain the pressure on the stem side 6 within a pre-established "balancing" pressure range.
The electronic regulation valve 11 is controlled by the value of the pressure on the stem side 6 through interposition of a pressure reducing valve 13.
Of course, starting operation of the electronic control valve 11 is determined by its necessary adjustment, with which the minimum and maximum values that define the range of action of the "balancing" pressure have been set in advance. Therefore, during the lowering step, i.e. the return of the stem, the actual pressure, as reduced by the reducing valve 13, which is detected at the rod side 6 of the double-acting hydraulic cylinder 4, operates the shut-off valve 10.
In other words, the shut-off valve 10 is operated hydraulically through the interposition of the pressure reducing valve 13 and is modulated by the electronic control valve 11 which is a proportional valve.
The combination of the pressure reducing valve 13 and the electronic proportional control valve 1 1 is indicated by the acronym EVP, and hydraulically controls the shut-off valve 10 according to the methods described above.
In this way, all safety measures of the machine and the control of the lowering speed of the hoisting arm remain managed by the hydraulic distributor 7.
The action of the EVP system, including the electronic control valve 11 , thus avoids the inconvenience of possible repeated closing of the shut-off valve 10, which would cause a kind of unwanted "hopping" of the telescopic hoisting arm 3 and the load it supports, thus allowing a continuous and shock-free lowering of the piston stem of the hydraulic actuator consisting of the double acting hydraulic cylinder 4.
This allows the oil pressure on the piston stem side 5 to be maintained within a set interval. This also allows achieving the result of smoothing the abrupt start of the movement, allowing instead gradual start and operation. Operation is simple: when the operator gives the lowering command for the telescopic hoisting arm 3, the hydraulic distributor 7 is used to send oil to the chamber at the stem side 6 of the double acting hydraulic cylinder 4. The electronic control valve 11 operates in such a way that the pressure on the stem side 6 starts to rise, until a certain pre-set value is reached, when the shut-off valve 10 starts to open more and more under control by the electronic regulating valve 11 and hydraulically operated by the pressure on the stem side 6 through the reducing valve 13, so gradually lowering the telescopic hoisting arm 3.
As the opening increases, the lowering speed of the telescopic hoisting arm 3 increases progressively.
As soon as the lowering speed increases above a certain limit, the pressure on the stem side may decrease 6, which would cause the electronic control valve 11 to come into operation, which would command the shut-off valve 10 to reduce its opening, in order to keep the pressure on the stem side 6 within a predetermined minimum and maximum limit.
It will be appreciated that only the hydraulic distributor 7 always controls the lowering speed of the arm.
If, for any reason, the electronic control valve 11 is blocked, even if it is fully open, the telescopic hoisting arm 3 would never fall down, because without pressure on the stem side 6, which occurs only with the opening of the distributor and therefore with the consent of the operator, the shut-off valve 10 does not open mechanically.
This means that all the safety features on the machine are not reduced or dropped. According to a second embodiment of the invention, the movement of the telescopic hoisting arm 3 is carried out by means of two double-acting hydraulic actuators or hydraulic cylinders 4 equal to each other, which work together in conjunction with the hydraulic operation of the telescopic hoisting arm 3, both on lifting and lowering.
Each double acting hydraulic actuator or hydraulic cylinder 4 is served by a hydraulic control circuit, which is connected to the same hydraulic distributor 7 from which, for each of them, a supply line 8 for feeding the bottom side 5 and a supply line 9 for feeding the stem side 6 originate.
On each of the supply lines 8 to the bottom side 5 there is a shut-off valve 10 with the function of intercepting and regulating the flow coming out of the relative bottom side 5.
Each double acting hydraulic actuator or hydraulic cylinder 4 is fed by a hydraulic control circuit, connected to the same hydraulic distributor 7 from which, for each double-acting hydraulic actuator or hydraulic cylinder 4, the supply line 8 for feeding the bottom side 5 and supply line 9 for feeding the stem side 6 originate, as previously mentioned.
An electronic regulation valve 11 is operated by the signal originated by a pressure transducer 12 in accordance with a pressure value detected at the stem side 6 of the double-acting hydraulic actuators or hydraulic cylinders 4.
The electronic regulation valve 11 is adjusted to intervene on the shut-off valves 10 in order to control and increase their openings when the pressure of the stem side 6, reported by the pressure transducer 12, reaches a preset minimum value and to open the valves up to reaching pressures at stem side 6 having a predetermined value.
If the pressure on the stem side falls down, the opening of valve 10, controlled by the electronic control valve 11 , is reduced (when the movement stops it is completely closed), so as to maintain the pressure on the stem side (6) within a pre-established "balancing" pressure range.
The electronic regulation valve 11 is adjusted to intervene on the shut-off valves 10 in order to control and increase their openings when the pressure of the stem side 6, reported by the pressure transducer 12, reaches a pre-set minimum threshold.
If the pressure on the stem side falls down, the openings of valves 10, controlled by the electronic control valve 11 , are reduced (when the movement stops they are completely closed), so as to maintain the pressure on the stem side within a pre-established "balancing" pressure range.
The electronic regulation valve 11 is controlled by the value of the pressure on the stem side 6 through interposition of a pressure reducing valve 13.
In other words, the electronic regulation valve 11 acts on the shutoff valves 10 so as to gradually increase their opening starting when the pressure at the stem side 6 reaches a preset minimum threshold, and to reduce, also gradually, the opening in case the pressure on the stem side is reduced, so as to maintain on the stem side a pre-set so called pressure "balancing" value. Of course, starting operation of the electronic control valve 11 is determined by its necessary adjustment, with which the minimum and maximum values that define the range of action of the "balancing" pressure have been set in advance.
In other words, each shut-off valve 10 is operated by the value of the pressure at the side of the stem 6 through the interposition of a pressure reducing valve 13 and is modulated by the electronic control valve 11.
A connection 16 has been introduced between the chambers at the bottom sides 5 and a similar connection 17 has been inserted between the two chambers at the stem sides 6, which ensures stability and uniformity of pressures within the two chambers.
In particular, the electronic regulation valve 11 operates on both shut-off valves 10 in accordance with the methods previously illustrated, carrying out gradual interventions, without abrupt movements or shocks.
In this way, the two double-acting hydraulic cylinders 4 can be operated synchronously in a simple and effective manner.
Numeral 14 indicates the driving line connecting the second shut-off valve 10, operating on the bottom side 6, to the electronic regulation valve 11 of the second double-acting hydraulic actuator or hydraulic cylinder 4.
A parachute valve 15 is arranged and operates along the bottom side balancing line 16 of the two double-acting hydraulic actuators or hydraulic cylinders 4.
The parachute valves 15 operate in the same way on the bottom sides of the double acting hydraulic actuators or hydraulic cylinders 4, are connected to each other by a connection 16 and have the task of preventing both chambers from emptying in the event of a breakage of a pipe.
This allows the double acting hydraulic actuators or hydraulic cylinders 4 to work in synchronism, especially during the lowering step, guaranteeing the safety standards required by the regulations in force.
The modes of operation are basically those of the first illustrated embodiment characterized by the presence of a single double acting hydraulic actuator or hydraulic cylinder.

Claims

1 ). Apparatus for regulate the stroke of double-acting hydraulic actuators of the type used for hydraulic actuation of maneuvering members of operating machines, comprising double-acting hydraulic actuator or hydraulic cylinders (4), a hydraulic control circuit, a hydraulic distributor, a pressure transducer, wherein each single double-acting hydraulic actuator or hydraulic cylinder (4) is supplied by the hydraulic control circuit connected to the hydraulic distributor from which a line originates for feeding the bottom side and a line originates for feeding the stem side, wherein a shut-off valve (10) is provided on the supply line (8) to the bottom side (5) with the task of intercepting and regulating the outlet flow characterized in that the shut-off valve (10) being hydraulically operated by the pressure value at the stem side (6) through interposition of a pressure reducing valve (13) and modulated by an electronic regulation valve (11 ) to which it is hydraulically connected; the electronic regulation valve (11 ) being operated by the signal originated by a pressure transducer (12) in accordance with a pressure value detected at the stem side (6) and being calibrated in order to act on the shut-off valve (10) so as to control and increase opening thereof upon reaching a pressure of a predetermined minimum value at the stem side 6, and to increase the until thereof up to reaching a pressure 6 of a predetermined value at the stem side 6, it being provided that when the pressure at the stem side decreases, opening of the valve 10, controlled by the electronic regulation valve 1 1 , is reduced, in the event that the movement stops up to complete closure, so as to maintain the pressure at the stem side (6) within a pre-established "balance" pressure range.
2). Apparatus according to claim 1 , characterized in that the electronic regulation valve (11 ) is a proportional type one and acts on the shut-off valve (10) so as to gradually increase its opening starting from when the pressure at the stem side (6) reaches a preset minimum value.
3).Apparatus for regulating the stroke of double-acting hydraulic actuators of the type used for hydraulic actuation of maneuvering members of operating machines, comprising double-acting hydraulic actuator or hydraulic cylinder (4), a hydraulic control circuit, a hydraulic distributor, a pressure transducer, wherein two or more double-acting hydraulic actuators or hydraulic cylinders (4) cooperate together as a couple for said hydraulic actuation and each double-acting hydraulic actuator or hydraulic cylinder (4) is supplied by the hydraulic control circuit connected to the hydraulic distributor (7) from which a line originates for feeding the bottom side and a line originates for feeding the stem side, wherein a shutoff valve is provided on the supply line to the bottom side with the task of intercepting the outlet flow characterized in that said shutoff valves (10) are both connected to a same electronic regulation (11 ) operated by the signal originated by a pressure transducer (12) in accordance with a corresponding pressure value detected at the stem side (6) of one of the hydraulic actuators or hydraulic cylinders (4) to operate the shut-off valves 10 so as to control and increase opening thereof upon reaching a pressure at the stem side 6 reported by the pressure transducer 12, having a preset minimum value and up to reaching a pressure at stem side (6 ) having a predetermined value; both the shut-off valves 10 being operated by the pressure value at the stem side (6) of the hydraulic actuators or hydraulic cylinders (4) through the interposition of a pressure reducing valve (13) and the modulating action of an electronic regulation valve (11 ), so as to maintain the pressure at the stem side (6) within a pre-established range.
4). Apparatus according to claim 4, characterized by including a parachute valve (15) applied to the bottom side (6) of each double acting hydraulic cylinder hydraulic actuator 4; said parachute valves (15) operating in the same manner on the respective bottom sides and being hydraulically connected directly to one another by means of a hydraulic connection 16 having the task of balancing the pressure at the bottom sides of the two cylinders.
PCT/IB2019/000015 2018-02-15 2019-02-11 Apparatus for regulating the stroke of double-acting hydraulic actuators Ceased WO2019158989A1 (en)

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IT201800002731A IT201800002731A1 (en) 2018-02-15 2018-02-15 EQUIPMENT FOR REGULARIZING THE STROKE OF DOUBLE ACTING HYDRAULIC ACTUATORS
IT102018000002731 2018-02-15

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CN114658702A (en) * 2022-03-30 2022-06-24 三一汽车制造有限公司 Control systems, booms and work machines

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IT202200017229A1 (en) * 2022-08-11 2024-02-11 Bosch Gmbh Robert CONTROL SYSTEM FOR AN ACTUATOR CYLINDER

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US20130298541A1 (en) * 2012-05-10 2013-11-14 Eaton Corporation Load energy assist and horsepower management system
EP2667038A2 (en) * 2012-05-25 2013-11-27 Wessel-Hydraulik GmbH Hydraulic circuit assembly
WO2016200272A1 (en) * 2015-06-12 2016-12-15 National Oilwell Varco Norway As Improvements in the control of hydraulic actuators

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US20130298541A1 (en) * 2012-05-10 2013-11-14 Eaton Corporation Load energy assist and horsepower management system
EP2667038A2 (en) * 2012-05-25 2013-11-27 Wessel-Hydraulik GmbH Hydraulic circuit assembly
WO2016200272A1 (en) * 2015-06-12 2016-12-15 National Oilwell Varco Norway As Improvements in the control of hydraulic actuators

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114658702A (en) * 2022-03-30 2022-06-24 三一汽车制造有限公司 Control systems, booms and work machines

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EP3752739B1 (en) 2022-03-09
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