• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Method for determining a load (2) lifted by actuator (27) in a hydraulic lifting device, in particular forklifts based on at least one upward and downward displacement of actuator. A pressure signal is provided by pressure gauge (16), a deviation signal (9) is provided on the basis of flow signal (11) and set point (3), and on the basis of the deviation signal there is provided a control signal (12) for controlling actuator (27), and a slope signal is provided by slope gauge (14). The weight of the load (2) is determined on the basis of the pressure signal (16), deviation signal (9), control signal (12) and slope signal (14). The pressure signal is recorded as a function of time, deviation signal (9) is determined on the basis of flow signal (11) and set point (3), control signal (12) is determined on the basis of deviation signal (9), and slope signal (14) is measured via slope meter, and the weight determination is performed in dependence on said deviation signal (9), control signal (12) and slope signal (14). Furthermore, a weighing device shown in FIG. 2nd
    公开号:DK201800435A1
    申请号:DKP201800435
    申请日:2018-08-01
    公开日:2020-02-27
    发明作者:Winther Hansen Torben
    申请人:INS - Europe；
    IPC主号:
    专利说明:

    The invention relates to a method and a weighing device for determining a load lifted by a hydraulic lifting device, such as e.g. a forklift, front loader and telescopic machine, and which includes a hydraulic actuator to perform the lift. The weight determination is based on at least one upward and one downward actuator offset, where the pressure in the actuator is measured during the offset by a pressure gauge, and where constant and the same speed of actuator offset is maintained in both directions in measuring and regulating the flow to the actuator and that a deviation-dependent signal is provided which signals that the actuator's shear rate is constant and has a value set via a set point, and where a slope-dependent signal is provided by measuring the slope of the actuator relative to the direction of gravity in two mutually perpendicular axes with a slope gauge. The pressure signal, the deviation-dependent signal and the slope signal are connected to a display unit which makes weight determination based on the measured pressure signal and the deviation-dependent signal as well as the slope-dependent signal.
    Weight determination of the above-mentioned type applies in connection with transport of e.g. freight, sand and stone. The method is used in weighing systems mounted on it
    eg. forklifts, front loaders and telescopic machines, whereby weight determination of the goods can be determined without driving to a remote stationary weighing system. Some of the known methods make weight determination with the hydraulic lifting device in motion, thereby reducing friction in bearings, sliding surfaces and actuators, the dynamic friction being less than static friction.
    In a known method DE4328148 (A1), this is done by a hydraulic forward or reverse flow so that the lifting device is either raised or lowered at a uniform speed while recording the weight of the load. A disadvantage of this method is that the measurement accuracy is relatively poor, since measuring errors of up to ± 1 to ± 2% of the lifting capacity of the lifting device must be expected. The reason for the relatively high inaccuracy is due to the mechanical friction in the lifting device, which thus absorbs some of the force's load, and also changes from hour to hour. In the hydraulic piping between the actuator and the pressure gauge, a hydraulic pressure drop is caused by the flow, which contributes to further measurement errors. This pressure drop changes with the size of the flow and the viscosity of the hydraulic medium, which depends on the temperature of the medium. As the hydraulic systems produce heat, the viscosity of the medium and thus the accuracy of the weight determination depends on, for example, how long the lifting device has been in use.
    Another known method EP1893955 (B1) utilizes measurement of pressure and flow when the load is raised and lowered, respectively, thereby balancing the sources of error that change signs with the direction of the actuator offset and by compensating for the different and varying shear rates of the actuator. Due to the viscosity changes in the hydraulic medium, it is still a challenge to obtain sufficient and stable road accuracy. In addition, hydraulic lifting devices are often used in connection with vehicles that are not on a horizontal surface, which results in weighing errors caused by the inclination of the lifting device in relation to the direction of gravity.
    DK 2018 00435 A1
    The invention provides a method that significantly reduces weighing sweeps by controlling and maintaining constant and equal rates of actuator displacement in both directions, and in particular by generating a deviation-dependent signal which ensures that pressure readings are recorded only under the above conditions, eliminating weighing errors caused of acceleration forces and weighing errors caused by changes in the viscosity of the hydraulic fluid due to its changing temperature. In addition, the slope of the lifting device is compensated in relation to the direction of gravity caused by the nature of the underlay or by the lifting of the lifting device by heavy load. These advantages mean that a road accuracy in the order of ± 0.1% of the lifting capacity of the lifting device can be obtained, even under adverse conditions.
    This is achieved according to the invention by registering an deviation-dependent parameter for the actuator's shear rate, using a control parameter for controlling the actuator's speed, by registering a slope-dependent parameter, and by carrying out the weight determination according to the deviation-dependent parameter and by a control parameter for regulation. of the actuator as well as of the slope dependent parameter.
    The invention is based on the physical law that mechanical friction between two surfaces is a force that opposes the motion and is proportional to the normal force with which the two surfaces affect each other and are independent of the size of the surfaces. This causes the direction of friction to be opposite to the direction of movement of the surfaces. The invention is also based on the physical law that the size and direction of a hydraulic pressure drop in a piping in which there is a flow also depends on the size and direction of the flow. This means that, provided that the actuator displacement takes place at a constant and the same rate (via a variable pump or other type of flow regulator), friction and pressure drop in actuator displacement in both directions are identical, but the signs change with the displacement direction. On the other hand, the sign of the force effects of the load remains unchanged even if the shear direction of the actuator changes. Therefore, by multiplying with a proportionality constant, half the sum of the recorded pressure values, measured via a pressure gauge under the actuator's upward and subsequent downward direction, is an expression of the weight of the load and lifted parts of the lifting device. Since the frictions in the two directions are equal but opposite, the sum of these becomes zero, which also applies to pressure drops in piping, where the sum of pressure drops also becomes zero. To ensure accurate weight determination, the actuator shear rate must be controlled and kept constant and of the same magnitude in both directions, and a signal must be provided that, when the deviation is sufficiently small, signals to the display unit that it may begin to detect actuator pressure.
    When the invention is in the neutral position, as shown in FIG. 1, the weight determination is not working. In this position, the hydraulic flow merely moves through the invention along the flow path marked by the drawn line, whereby the hydraulic lifting device can be used in the ordinary way.
    DK 2018 00435 A1
    When the invention is in the weighing position, as shown in FIG. 2, the weight determination is based on the load lifted by the actuator being subjected to at least one upward and one downward displacement and that the hydraulic pressure in the actuator is measured via a pressure gauge. The weighing is started by activating the display unit which connects power to a solenoid and thereby closes a bypass valve, thus establishing a flow path marked by the drawn line. Next, the hydraulic lifting device is supplied with a flow at least equal to the size of the flow set via a predetermined set point. The flow thus flows into the pipe system through a flow regulator and through the meter of the flow to an actuator that lifts the load. If the supply flow is greater than the flow set via the set point, the excess flow will flow through a pressure relief valve and back to the reservoir, which reduces power output in the flow regulator as the load is lifted. During the actuator offset, a flow signal proportional to the actuator shear rate is sent to a summation point where the flow signal is compared with the set point set flow that corresponds to a given rate of actuator offset. This provides a deviation-dependent signal which, via a process unit, controls the flow regulator to maintain the shear rate, as set in the set point. The deviation-dependent signal is sent to the display unit and is used here as a criterion for when a constant and desired actuator speed is obtained and when the display unit must start recording the pressure in the actuator. When the criterion is met, the display unit senses the pressure for a few seconds and then asks to have the load lowered, thereby flowing back from the actuator in exactly the same way, but in the opposite direction as during the lift. The shear speed of the actuator is controlled in the same way during lowering as during the lift, however the flow signal changes sign, which can be taken into account in several ways. After a period of time similar to lifting, the display unit has registered actuator displacement pressure in both directions and weight determination can now be performed by the display unit. During the above weighing process, the slope of the actuator is included, which is included in the weight determination. The position of the actuator is detected by a position meter, whereby a position signal is included in the weight determination. Eg. the hydrostatic pressure caused by the hydraulic fluid depends on the position of the actuator, and on forklifts varying lengths of chains and hydraulic hoses contribute to the load generated by the load. By means of a position signal, the aforementioned error contribution can be eliminated. In order to avoid unnecessary power consumption, a pressure relief system has been introduced to reduce the hydraulic pressure during upward actuator displacement. If the supplied flow at the lifting load is greater than necessary to achieve the set speed, set via the set point, the excess flow will flow through a pressure relief valve and back to the reservoir, at just the pressure needed to lift the load. Particularly with heavy loads, intrinsic vibrations (2-order components) in the lifting device are a problem. This problem is solved by detecting variations in either pressure signal or slope signal and wait to complete the weighing process until the oscillations have stopped. Since the temperature of the hydraulic system plays a role, among other things for the accuracy of the pressure gauge, variations in the temperature are measured and compensated via a temperature gauge, possibly embedded in the pressure gauge. For determining parts of the lifting weight, e.g. actuator piston rod, a special weight is made
    DK 2018 00435 A1 vote without load (reset), which is done only once. In subsequent weight determinations, the above weight is subtracted from the measured weight result of the weight determination load.
    In a particular method of weight determination, a parameter dependent on the position of the actuator is measured by means of a position meter. This compensates for position-dependent error contributions, for example from varying length and weight of chains and hoses in the lifting device.
    In another method of weight determination, a pressure relief system for reducing pressure and power consumption during actuator displacement has been introduced in the upward direction. Thus, during the actuator displacement, the flow flows into the pipe system, on to a flow regulator and through the meter of the flow to an actuator that lifts the load. If the supply flow is greater than the set point setpoint flow value, the excess flow will flow through a pressure relief valve and back to the reservoir, reducing the power consumption as much as possible.
    In a method of weight determination, a vibration-dependent parameter for damped oscillations in the lifting device is measured by pressure gauge or inclination gauge. Based on this oscillation-dependent parameter, pressure sensing in the actuator is awaited until the oscillations are sufficiently attenuated to avoid disturbing weight contribution.
    In a method of weight determination, a temperature dependent parameter is measured via the hydraulic medium by means of a temperature gauge which may be embedded in the pressure gauge. Based on the temperature-dependent parameter, temperature-dependent measurement errors are compensated.
    In the embodiment of the weighing device, consisting of a display unit containing a processor for weight determination of a load lifted by an actuator, the weight determination is based on displacement of the actuator in both directions, where a hydraulic pressure signal is measured and where via a flow signal, a set point and a summation point, a deviation signal is provided to control actuator offset, and where actuator inclination is measured and where measured pressure in actuator is compensated for this inclination and where the display unit is arranged to record an actuator deviation signal to determine when pressure measurements should be recorded. This provides a very good road accuracy in the order of ± 0.1% of the lifting capacity of the lifting device.
    In a particular embodiment of the weighing device, where the position of the actuator is determined at one or more points by means of a position meter and via one or more position sensors, the position measurement is based on either magnetic, inductive, optical or ultrasonic principles, whereby more possibilities for compensation of position dependent weighing errors are obtained.
    In another embodiment of the weighing device, a pressure relief valve for reducing hydraulic pressure and power consumption is provided, so that only the pressure required to carry out the weight determination is maintained, thereby reducing power consumption to a minimum.
    In one embodiment of the weighing device, where intrinsic vibrations in the lifting device are detected via vibrations in the pressure signal or the slope signal, registration of pressure in the actuator is awaited until vibrations in the lifting device have been stopped, thereby avoiding disturbances in the road accuracy.
    In one embodiment of the weighing device, where the temperature of the hydraulic medium is measured with a temperature meter and where the pressure gauge is exposed to variations in temperature, e.g. via surroundings
    DK 2018 00435 A1 or heated hydraulic fluid is thus compensated for the pressure gauge temperature-dependent measurement error, which results in improved temperature stability.
    The invention is explained in more detail below with reference to the two drawings fig. 1 and FIG. 2nd
    FIG. 1 shows the invention in a neutral position where the weight determination is not functioning and where the lifting device is used as normal, and
    FIG. 2 shows the invention in weighing position, where weight determination is made together with a hydraulic lifting device consisting of an actuator on which a load is placed.
    In the neutral position of FIG. 1, the weight determination is not operative, whereby the flow (20) simply flows through the pipe system of the invention along the flow path marked by the drawn line. Thus, the flow (20) flows into the pipe system through the bypass valve (15) and through a meter (18) of flow to an actuator (27), thereby lifting the load (2).
    In the weighing position of FIG. 2, the weight determination is based on the load (2) being lifted by the actuator (27), subjected to at least one upward and one downward displacement, and that the hydraulic pressure in the actuator (27) is measured via a pressure gauge (16). The weighing is started by activating the display unit (1) which connects solenoid (17) power, thereby closing the bypass valve (15), thus establishing a flow path marked by the drawn line. Next, the hydraulic lifting device is supplied with a flow (20) at least equal to the size of the flow set via a predetermined set point (3). The flow thus flows into the pipe system through a flow regulator (13) and through the meter (18) of the flow to an actuator (27) which lifts the load (2). If the supply flow is greater than the flow set via the set point (3), the excess flow (24) will flow through a pressure relief valve (22) and back to the reservoir (23), which reduces power output in the flow regulator (13) when the load (2) lifted. During the displacement of the actuator (27), a flow signal (11) proportional to the actuator shear rate is sent to a summing point (6), where the flow signal (11) is compared with the set flow (set) of the set point (3) corresponding to a given speed of the actuator. displacement. Hereby, a deviation-dependent signal (9) is provided which via flow unit (10) and control signal (12) controls flow regulator (13) to maintain the shear rate of actuator set at set point (3). In an alternative embodiment of the invention in which the connections (4) and (5) are established, part or all of the control circuit consisting of (3), (6) and (10) can be performed by the display unit (1). The deviation-dependent signal (9) is sent to the display unit (1) where it is used as a criterion for when a constant and desired actuator speed is obtained and when the display unit (1) starts recording the hydraulic pressure. When the criterion is met, the display unit (1) records the pressure for a few seconds and then requests that the load (2) is lowered, whereby the flow (25) returns from the actuator (27) along the same flow path, but in the opposite direction as during the lift. . The shear speed of the actuator is controlled in the same way during lowering as during the lift, however the flow signal (11) changes sign, which can be taken into account in several ways. After a corresponding period of time, as in lifting, the display unit (1) has registered actuator offset pressure in both directions and weight determination can now be performed by
    DK 2018 00435 A1 display unit (1). During the aforementioned weighing process, the slope of the actuator (27) is recorded via a 2-axis slope meter (14) and provides a slope signal which is included in the weight determination to increase its accuracy. An improvement is achieved in that a position meter (7) detects the position of the actuator (27) via one or more position sensors (8) and produces a position signal which is included in the weight determination. Eg. the hydrostatic pressure caused by the hydraulic medium (26) depends on the position of the actuator, and on forklifts varying lengths of chains and hydraulic hoses contribute to a varying pressure, in addition to the pressure generated by the load (2). Another method is that the weight determination is always started at the same actuator position, which can be done with a simple position meter in just one point. The aforementioned error contribution can be determined and eliminated by means of the position-dependent signal. Another improvement is achieved by introducing a pressure relief valve (22) to reduce the hydraulic pressure, thereby avoiding unnecessary power consumption during upward actuator displacement. If the supplied flow at the lifting load (2) is greater than necessary to achieve the set speed, set via the set point (3), the excess flow (24) flows through a pressure relief valve (22) back to the reservoir (23), at just the pressure needed to lift the load (2) and determined by pilot pressure (21). A further improvement is achieved by detecting intrinsic oscillations in the lifting device, either via variations in signal from pressure gauge (16) or from slope gauge (14), so as to wait to carry out the weighing process until the oscillations have ceased. Improved road accuracy is achieved by measuring and compensating for temperature changes in the hydraulic system. The temperature is measured via a temperature gauge, possibly embedded in a pressure gauge (16). In this way, the pressure gauge's temperature-dependent measurement error can be significantly reduced.
    For determining parts of the lifting weight, e.g. actuator piston rod (19), a special weight determination without load (reset) is made, which is done only once. Subsequent weight determinations subtract the aforementioned specific gravity, thereby producing the weight of the load.
    The invention consisting of the components (28), display unit (1) and position sensor (8) can either be combined into one unit or be decentralized, so that some of the components of the invention, e.g. flow regulator (13), pressure relief valve (22) or the like may be part of the hydraulic lifting device design.
    One skilled in the art will be able to practice the invention in accordance with the teachings herein described, and to develop functions on his own to practice variants of the invention.
    权利要求:
    Claims (9)
    [1]
    claims
    A method of weight determination, as shown in Figure 2, of a load (2) lifted by an actuator (27), wherein the weight determination is based on at least one upward and one downward displacement of the actuator, the actuator being displaced due to an initial flow (20). ) in the hydraulic pipe system, where the hydraulic pressure is measured by means of a pressure gauge (16), thereby providing a pressure signal and providing a deviation dependent via flow signal (11) based on actuator shear speed and via set point (3) parameter (9), and on the basis of which there is provided a control parameter (12) for controlling the actuator and wherein the inclination of the actuator in relation to the direction of gravity is measured by means of a slope gauge (14), thereby providing a slope parameter, characterized by, that a deviation-dependent parameter is recorded, using a control parameter, by registering a slope-dependent parameter, and by weighting the measurement is performed depending on the deviation-dependent parameter and the control parameter as well as the slope-dependent parameter.
    [2]
    The method of weight determination according to claim 1, wherein a parameter dependent on the position of the actuator is measured by means of a position meter (7) and position sensor (8), thereby providing a position dependent parameter, characterized in that the weight determination is carried out in dependence on the position-dependent parameter.
    [3]
    The method of weight determination according to claim 1, wherein pressure relief system (22) is introduced for reducing pressure and power consumption, characterized in that the weight determination is carried out by means of this pressure relief system for reducing the power consumption.
    [4]
    The method of weight determination according to claim 1, wherein a parameter dependent on damped oscillations in the lifting device is provided via pressure signal or inclination signal, thereby providing a vibration dependent parameter, characterized in that the weight determination is performed in dependence on the vibration dependent parameter.
    [5]
    The method of weight determination according to claim 1, wherein a parameter which is dependent on the temperature of the hydraulic medium is measured with a temperature meter optionally embedded in a pressure gauge (16), thereby providing a temperature dependent parameter, characterized in that the weight determination is carried out in dependence on it. temperature dependent parameter.
    [6]
    A weighing device consisting of a system comprising a processor for weight determination of a load lifted by an actuator, the weight determination being based on at least one upward and one downward displacement of the actuator, wherein the actuator is displaced due to an initial flow (20). the hydraulic pipe system, wherein the hydraulic pressure is measured by a pressure gauge (16), thereby providing a pressure signal and providing a deviation signal (9) via flow signal (11) based on actuator shear speed and (9) ) and that, on the basis of the deviation signal, a control signal (12) for controlling actuator is provided, and that the control signal is produced, inter alia, in the form of, but not limited by, hydraulics, mechanics, electronics, software or in a combination thereof, and the slope of the actuator relative to the direction of gravity
    DK 2018 00435 A1 is measured by means of a slope meter (14), thereby providing a slope signal, characterized in that the weighing device is arranged to detect a deviation signal, and to use a control signal, and to record a slope signal, and to execute a slope signal. the weight determination in dependence on the deviation signal and the control signal as well as the slope signal.
    5
    [7]
    The weighing device according to claim 6, wherein the position meter (7) and position sensor (8) can be based on different principles, characterized by position measurement at either one point or at several points based on, inter alia, magnetic, inductive, optical, mechanical, hydraulic or ultrasonic principles.
    [8]
    Weighing device according to claim 6, wherein a pressure relief valve (22) is introduced for reducing pressure and power consumption, characterized in that the pressure relief valve reduces the power consumption.
    [9]
    The weighing device according to claim 6, wherein attenuated oscillations in the pressure signal or inclination signal of the lifting device are measured, thereby providing an oscillation signal, characterized in that the weight determination is made in dependence on the oscillation signal.
    Weighing device according to claim 6, wherein the temperature of the hydraulic medium is measured with a temperature meter, optionally embedded in a pressure gauge (16), whereby a temperature signal is provided, characterized in that the weight determination is carried out in dependence on the temperature signal.
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    同族专利:
    公开号 | 公开日
    US20200041328A1|2020-02-06|
    EP3604201A1|2020-02-05|
    DK180121B1|2020-05-19|
    EP3604201B1|2021-11-10|
    PL3604201T3|2022-01-31|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE4328148C2|1993-08-21|2001-02-22|Bosch Gmbh Robert|Method for a device for determining the weight of loads attached to a tractor|
    DK1893955T3|2005-06-03|2009-11-16|Torben Winther Hansen|Method of determining a load carried by a lifting arm of a lifting device and weighing device|
    DK179285B1|2016-04-29|2018-04-03|Ins Europe|Method of weight determination of a load carried by a lifter of a lifting device and weighing device|
    DK179160B1|2016-05-27|2017-12-18|INS - Europe|Method of weight determination of a load carried by a lifter of a lifting device and weighing device|
    CN107857212B|2017-09-26|2019-06-25|林德（中国）叉车有限公司|A kind of fork truck maximum lift height method for limiting and system|
    法律状态:
    2020-02-27| PAT| Application published|Effective date: 20200202 |
    2020-05-19| PME| Patent granted|Effective date: 20200519 |
    优先权:
    申请号 | 申请日 | 专利标题
    DKPA201800435A|DK180121B1|2018-08-01|2018-08-01|Hydraulic weight determination, method of weight determination of a load by means of a hydraulic lifting device|DKPA201800435A| DK180121B1|2018-08-01|2018-08-01|Hydraulic weight determination, method of weight determination of a load by means of a hydraulic lifting device|
    EP19184718.5A| EP3604201B1|2018-08-01|2019-07-05|Hydraulic weight determination|
    PL19184718T| PL3604201T3|2018-08-01|2019-07-05|Hydraulic weight determination|
    US16/523,816| US20200041328A1|2018-08-01|2019-07-26|Hydraulic weight determination|
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