EP0557390B1 - Method and device for preventing the puncture of a load-sensing and pressure-compensating control system for a hydraulic crane - Google Patents
Method and device for preventing the puncture of a load-sensing and pressure-compensating control system for a hydraulic crane Download PDFInfo
- Publication number
- EP0557390B1 EP0557390B1 EP91920481A EP91920481A EP0557390B1 EP 0557390 B1 EP0557390 B1 EP 0557390B1 EP 91920481 A EP91920481 A EP 91920481A EP 91920481 A EP91920481 A EP 91920481A EP 0557390 B1 EP0557390 B1 EP 0557390B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- flow
- crane
- control
- maximum
- hydraulic
- 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.)
- Revoked
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C13/00—Other constructional features or details
- B66C13/18—Control systems or devices
Definitions
- the present invention relates to a method of preventing puncture in a load-sensing and pressure-compensating control system for a hydraulic crane when the hydraulic flow requested to the different functions of the crane exceeds the maximum hydraulic flow available.
- the invention further concerns a device for implementing the method.
- Fig. 1 illustrates a conventional hydraulic crane which includes a body 1, a first boom section 2 articulated to the body 1, an outer boom 3 articulated to the first boom section 2, and an extension boom 4 fixed to the outer boom 3.
- the first boom section is operated by means of a hydraulic lifting cylinder 5
- the outer boom 3 is operated by means of a hydraulic outer boom cylinder 6
- the extension boom 4 is operated by means of a hydraulic extension boom cylinder 7.
- the control system for controlling the different crane functions comprises a pump 10 which pumps hydraulic fluid from a tank 9 to a directional-control-valve block 12 containing a directional-control-valve section for each of the cylinders 5-7, to which the hydraulic fluid is supplied in conventional manner as a function of the position of the slide member in each valve section.
- the directional-control-valve sections are remote-controlled by a control means 13 with one lever for each crane function.
- the signals from the control means 13 are transmitted via a cable or a wireless connection to a microprocessor 16 which in turn controls the position of the slide members in the valve sections of the directional-control-valve block 12 as a function of the value of the respective control signal from the control means.
- control system In advanced cranes, the control system, or more precisely the directional-control-valve block 12, can be load-sensing and pressure-compensating, which means that a certain lever position on the control means 13 produces a certain flow to the associated crane function, regardless of the load on this function and regardless of the flow to and load on the remaining crane functions.
- the object of the present invention is, therefore, to provide a method and a device which solve the above-mentioned problem and make it possible to use pumps with lower maximum flow without risking a puncture of the control system.
- step c) is preferably repeated after the scaling down.
- the scale factors may then be so chosen that there is only a slight scaling down, since there will be a renewed check on whether the sum is smaller than the maximum-flow value, so that the scaling down can be repeated if need be.
- the scale factors can be the same for all the functions or, as recited in appended claim 3, be different for different crane functions, so that certain functions may be prioritised.
- the invention also concerns a device for implementing the method, which shows the features recited in appended claim 5.
- the invention can be applied to hydraulic cranes with load-sensing and pressure-compensating control systems.
- the crane functions of such a crane may, for instance, include lifting/lowering the first boom section, tilting the outer boom, extending/retracting the extension boom, lifting/lowering the jib boom, and rotating the crane.
- the control signals from the control means are processed in the following manner (see the flow chart in Fig. 2).
- a first step 20 is measured the value of each of the control signals Q1-Q N representing a flow requested to a crane function and being transmitted from the control means 13 to the microprocessor 16.
- the thus-established values of the control signals Q1-Q N are added up, which gives the sum Q p .
- the sum Q p is, in step 22, compared with a maximum-flow value Q max representing the maximum hydraulic flow available from the pump.
- control signals are, in step 25, transmitted as they are to the respective directional-control-valve section in the directional-control-valve block 12. This program is repeated at suitable intervals, thereby avoiding a puncture of the system.
- control-signal value need not be measured directly after the control means 13, but may instead be measured by establishing the displacement of the slide member in the valve 12 caused by the signal.
- the thus-established values are returned to the microprocessor 16, whereupon the method is implemented in the manner described above.
- This variant may be used not only in remote-controlled systems, but also in hand-lever-controlled, load-sensing and pressure-compensating valves.
Landscapes
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Mechanical Engineering (AREA)
- Control And Safety Of Cranes (AREA)
- Jib Cranes (AREA)
- Fluid-Pressure Circuits (AREA)
Abstract
Description
- The present invention relates to a method of preventing puncture in a load-sensing and pressure-compensating control system for a hydraulic crane when the hydraulic flow requested to the different functions of the crane exceeds the maximum hydraulic flow available. The invention further concerns a device for implementing the method.
- Fig. 1 illustrates a conventional hydraulic crane which includes a body 1, a first boom section 2 articulated to the body 1, an outer boom 3 articulated to the first boom section 2, and an extension boom 4 fixed to the outer boom 3. The first boom section is operated by means of a hydraulic lifting cylinder 5, the outer boom 3 is operated by means of a hydraulic outer boom cylinder 6, and the extension boom 4 is operated by means of a hydraulic extension boom cylinder 7.
- The control system for controlling the different crane functions (lifting/lowering by means of the lifting cylinder, tilting by means of the outer boom cylinder, and extending/retracting by means of the extension boom cylinder) comprises a
pump 10 which pumps hydraulic fluid from a tank 9 to a directional-control-valve block 12 containing a directional-control-valve section for each of the cylinders 5-7, to which the hydraulic fluid is supplied in conventional manner as a function of the position of the slide member in each valve section. The directional-control-valve sections are remote-controlled by a control means 13 with one lever for each crane function. The signals from the control means 13 are transmitted via a cable or a wireless connection to amicroprocessor 16 which in turn controls the position of the slide members in the valve sections of the directional-control-valve block 12 as a function of the value of the respective control signal from the control means. - In advanced cranes, the control system, or more precisely the directional-control-valve block 12, can be load-sensing and pressure-compensating, which means that a certain lever position on the control means 13 produces a certain flow to the associated crane function, regardless of the load on this function and regardless of the flow to and load on the remaining crane functions.
- However, this only applies as long as the sum of the hydraulic flows requested by the levers of the control means 13 to the different crane functions, is smaller than or equal to the maximum hydraulic flow that the
pump 10 can provide. When the total hydraulic flow requested to the different crane functions exceeds that available from the pump, the flow is primarily directed to the crane function(s) with the lightest load. At worst, no hydraulic flow at all is supplied to the function(s) with the heaviest load, and these will then stop working. If this happens suddenly, there may arise violent jerks in the movements of the crane which are extremely unpleasant and even may lead to overloading of the crane. This phenomenon of one or more crane functions being deprived of flow is called puncture. - The only prior-art solution to this problem consists in oversizing the pump so that the flow therefrom will at all times be sufficient, regardless of the operations indicated by the operator on the control means. However, such oversizing renders the crane control system more expensive and energy-intensive. In mobile systems, it may in addition be difficult to make room for large pumps.
- The object of the present invention is, therefore, to provide a method and a device which solve the above-mentioned problem and make it possible to use pumps with lower maximum flow without risking a puncture of the control system.
- This object is achieved by a method which is characterised by
- a) measuring the value of each control signal representing a flow requested to a crane function;
- b) adding up the measured values of the control signals; and
- c) comparing the sum of the control-signal values with a maximum-flow value representing the maximum hydraulic flow available and, should the sum exceed the maximum-flow value, multiplying each control signal by a scale factor ki, wherein i = 1, ...N, and ki <1, before supply to a respective means for controlling the hydraulic flow to a crane function, and, should the sum fall below the maximum-flow value, supplying each control signal unmodified to the respective means for controlling the hydraulic flow to a crane function.
- This ensures that a hydraulic flow is supplied to all the controlled crane functions, thus avoiding a puncture of the control system and eliminating the risk of overloading.
- As recited in appended claim 2, step c) is preferably repeated after the scaling down. The scale factors may then be so chosen that there is only a slight scaling down, since there will be a renewed check on whether the sum is smaller than the maximum-flow value, so that the scaling down can be repeated if need be.
- The scale factors can be the same for all the functions or, as recited in appended claim 3, be different for different crane functions, so that certain functions may be prioritised.
- The invention also concerns a device for implementing the method, which shows the features recited in appended claim 5.
- The invention can be applied to hydraulic cranes with load-sensing and pressure-compensating control systems. The crane functions of such a crane may, for instance, include lifting/lowering the first boom section, tilting the outer boom, extending/retracting the extension boom, lifting/lowering the jib boom, and rotating the crane.
- An embodiment of the present invention will be described below with reference to the accompanying drawings, in which
- Fig. 1,
- which already has been described, illustrates a conventional hydraulic crane with associated control system, and
- Fig. 2
- is a flow chart for implementing the method.
- In order to avoid that a load-sensing and pressure-compensating crane control system of the type illustrated in Fig. 1 is punctured when the hydraulic flow requested by an operator to the different crane functions exceeds the maximum hydraulic flow available, the control signals from the control means are processed in the following manner (see the flow chart in Fig. 2). In a
first step 20 is measured the value of each of the control signals Q₁-QN representing a flow requested to a crane function and being transmitted from the control means 13 to themicroprocessor 16. In thesubsequent step 21, the thus-established values of the control signals Q₁-QN are added up, which gives the sum Qp. Then, the sum Qp is, instep 22, compared with a maximum-flow value Qmax representing the maximum hydraulic flow available from the pump. Should the sum Qp exceed the maximum-flow value Qmax, the system would be punctured unless the control signals Q₁-QN were modified before being transmitted to the directional-control-valve block 12. To prevent such a puncture, each control signal Qi is, instep 23, multiplied by a scale factor ki, wherein i = 1, ...N, which optionally may be the same for all the control signals. Thereafter, the control signals Qi are, instep 24, scaled down to qi, and the adding up ofstep 21 and the comparison ofstep 22 are repeated. Should the sum Qp for the requested hydraulic flow still exceed the maximum-flow value Qmax, another scaling down of the control signals is performed. If, on the other hand, the sum Qp is smaller than or equal to the maximum-flow value Qmax, the control signals are, instep 25, transmitted as they are to the respective directional-control-valve section in the directional-control-valve block 12. This program is repeated at suitable intervals, thereby avoiding a puncture of the system. - It should also be pointed out that the control-signal value need not be measured directly after the control means 13, but may instead be measured by establishing the displacement of the slide member in the valve 12 caused by the signal. The thus-established values are returned to the
microprocessor 16, whereupon the method is implemented in the manner described above. This variant may be used not only in remote-controlled systems, but also in hand-lever-controlled, load-sensing and pressure-compensating valves. - Finally, it should be observed that, by using the flow chart in Fig. 2, the expert may easily implement the invention to take the shape of a program in the
microprocessor 16.
Claims (6)
- Method of preventing puncture in a load-sensing and pressure-compensating control system for a hydraulic crane when the hydraulic flow requested to the different functions of the crane exceeds the maximum hydraulic flow available,
characterised bya) establishing the value of each control signal (Q₁-QN) representing a flow requested to a crane function;b) adding up the established values of the control signals (Q₁-QN); andc) comparing the sum (Qp) of the control-signal values with a maximum-flow value (Qmax) representing the maximum hydraulic flow available and, should the sum (Qp) exceed the maximum-flow value (Qmax), multiplying each control signal by a scale factor ki, wherein i = 1, ...N, and ki <1, before supply to a respective means (12) for controlling the flow to a crane function, and, should the sum fall below the maximum-flow value, supplying each control signal unmodified to the respective means (12) for controlling the flow to a crane function. - Method as claimed in claim 1, characterised by repeating step c) after the multiplication by the scale factors ki.
- Method as claimed in claim 1 or 2, characterised by using scale factors ki with different values for the control signals to different crane functions.
- Method as claimed in any one of the preceding claims, characterised by establishing the value of each control signal (Q₁-QN) by measuring the displacement caused by said signal of a control element provided in each means (12) for controlling the flow to a crane function.
- Device for preventing puncture in a load-sensing and pressure-compensating control system for a hydraulic crane, said control system comprising load-sensing and pressure-compensating valve means (12) for controlling the hydraulic flow to the different crane functions, and means (13) for controlling the valve means (12) by control signals,
characterised by the device comprising
means for establishing the value of each control signal (Q₁-QN),
means for adding up the established values of the control signals (Q₁-QN),
means for comparing the sum (Qp) of the measured values with a maximum-flow value (Qmax) representing a maximum hydraulic flow available, and
means for multiplying the control signals by a scale factor ki, wherein i = 1, ...N, and ki <1, should the sum (Qp) exceed the maximum-flow value (Qmax). - Device as claimed in claim 5, characterised in that the means for establishing the control-signal values include means for establishing the displacement of a slide member in the valve means (12).
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9003656A SE467408B (en) | 1990-11-16 | 1990-11-16 | SETTING AND DEVICE FOR THE PREVENTION OF PUNCTIONING OF A LOADING AND PRESSURE COMPENSATING CONTROL SYSTEM FOR A HYDRAULIC CRANE |
SE9003656 | 1990-11-16 | ||
PCT/SE1991/000773 WO1992008666A1 (en) | 1990-11-16 | 1991-11-14 | Method and device for preventing the puncture of a load-sensing and pressure-compensating control system for a hydraulic crane |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0557390A1 EP0557390A1 (en) | 1993-09-01 |
EP0557390B1 true EP0557390B1 (en) | 1995-02-15 |
Family
ID=20380929
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP91920481A Revoked EP0557390B1 (en) | 1990-11-16 | 1991-11-14 | Method and device for preventing the puncture of a load-sensing and pressure-compensating control system for a hydraulic crane |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP0557390B1 (en) |
JP (1) | JPH06504512A (en) |
AT (1) | ATE118459T1 (en) |
DE (1) | DE69107472T2 (en) |
ES (1) | ES2068612T3 (en) |
SE (1) | SE467408B (en) |
WO (1) | WO1992008666A1 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0779239B2 (en) * | 1995-12-13 | 2006-09-13 | Liebherr-Werk Ehingen GmbH | Crane hoist control |
DK1490288T3 (en) * | 2001-11-28 | 2015-05-11 | Hojbjerg Maskinfabrik As | Load control system, preferably for boom cranes |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3638211A (en) * | 1969-10-08 | 1972-01-25 | Litton Systems Inc | Crane safety system |
US4222491A (en) * | 1978-08-02 | 1980-09-16 | Eaton Corporation | Crane operating aid and sensor arrangement therefor |
FR2504701A1 (en) * | 1981-04-22 | 1982-10-29 | Camiva | DEVICE FOR CONTROLLING AUTOMATIC CORRECTION OF DEVERS FOR DEPLOYABLE ORIENTABLE SCALE OR ARM-LIKE ARMOR ON VEHICLE |
DE3605462A1 (en) * | 1986-02-24 | 1987-08-27 | Mo N Proizv Ob Str Dorozh Mash | METHOD FOR SECURING SAFE OPERATION OF SELF-DRIVING Jib Cranes, AND SYSTEM FOR CARRYING OUT THE SAME |
-
1990
- 1990-11-16 SE SE9003656A patent/SE467408B/en not_active IP Right Cessation
-
1991
- 1991-11-14 ES ES91920481T patent/ES2068612T3/en not_active Expired - Lifetime
- 1991-11-14 AT AT91920481T patent/ATE118459T1/en not_active IP Right Cessation
- 1991-11-14 JP JP4500573A patent/JPH06504512A/en active Pending
- 1991-11-14 WO PCT/SE1991/000773 patent/WO1992008666A1/en not_active Application Discontinuation
- 1991-11-14 EP EP91920481A patent/EP0557390B1/en not_active Revoked
- 1991-11-14 DE DE69107472T patent/DE69107472T2/en not_active Revoked
Also Published As
Publication number | Publication date |
---|---|
SE9003656D0 (en) | 1990-11-16 |
ATE118459T1 (en) | 1995-03-15 |
SE467408B (en) | 1992-07-13 |
EP0557390A1 (en) | 1993-09-01 |
DE69107472T2 (en) | 1995-06-14 |
WO1992008666A1 (en) | 1992-05-29 |
SE9003656L (en) | 1992-05-17 |
ES2068612T3 (en) | 1995-04-16 |
DE69107472D1 (en) | 1995-03-23 |
JPH06504512A (en) | 1994-05-26 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7276669B2 (en) | Payload overload control system | |
US6983592B2 (en) | Mobile working machine | |
CA2060344C (en) | Control device for work machine | |
EP3257805A1 (en) | Hydraulic crane | |
JP4468703B2 (en) | Apparatus and method for controlling a machine | |
EP0731054A1 (en) | Mobile reach tower crane | |
JPH04303395A (en) | Control device for fork lift | |
EP3239092B1 (en) | Hydraulic crane | |
US6915599B2 (en) | System for controlling movement of a work machine arm | |
EP0557390B1 (en) | Method and device for preventing the puncture of a load-sensing and pressure-compensating control system for a hydraulic crane | |
US9334883B2 (en) | Method for controlling a hydraulic system of a working machine | |
SE1551349A1 (en) | Adaptive control of hydraulic tool on remote demolition robot | |
EP0397076A1 (en) | Electrohydraulic system | |
JPH01256496A (en) | Load vibration preventer at time of ungrounding of slinging load of crane with boom | |
US6459976B1 (en) | Method and system for controlling steady-state speed of hydraulic cylinders in an electrohydraulic system | |
RU2343104C2 (en) | Cargo-hoisting machine control system (versions) | |
EP4201865A1 (en) | A working equipment system, and a method of the working equipment system | |
JPH01256497A (en) | Load vibration preventer at time of ungrounding of slinging load of crane with telescopic boom | |
US20090220350A1 (en) | Method and apparatus for controlling a hydraulic system of a work machine | |
JP2986510B2 (en) | Swing control device | |
JP3323734B2 (en) | Work machine turning control device | |
JPH0440009Y2 (en) | ||
JP2000355497A (en) | Cylinder control device for cargo handling of forklift truck | |
EP1798188A2 (en) | Hydraulic crane | |
JPS60252805A (en) | Control of fluid actuator |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19930513 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE CH DE DK ES FR GB GR IT LI LU NL SE |
|
RBV | Designated contracting states (corrected) |
Designated state(s): AT DE ES FR GB IT NL |
|
17Q | First examination report despatched |
Effective date: 19940606 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AT DE ES FR GB IT NL |
|
REF | Corresponds to: |
Ref document number: 118459 Country of ref document: AT Date of ref document: 19950315 Kind code of ref document: T |
|
ITF | It: translation for a ep patent filed |
Owner name: BUGNION S.P.A. |
|
REF | Corresponds to: |
Ref document number: 69107472 Country of ref document: DE Date of ref document: 19950323 |
|
REG | Reference to a national code |
Ref country code: ES Ref legal event code: FG2A Ref document number: 2068612 Country of ref document: ES Kind code of ref document: T3 |
|
ET | Fr: translation filed | ||
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 19951019 Year of fee payment: 5 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 19951106 Year of fee payment: 5 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 19951107 Year of fee payment: 5 Ref country code: AT Payment date: 19951107 Year of fee payment: 5 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: ES Payment date: 19951113 Year of fee payment: 5 |
|
PLBI | Opposition filed |
Free format text: ORIGINAL CODE: 0009260 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: NL Payment date: 19951130 Year of fee payment: 5 |
|
PLBF | Reply of patent proprietor to notice(s) of opposition |
Free format text: ORIGINAL CODE: EPIDOS OBSO |
|
26 | Opposition filed |
Opponent name: MANNESMANN REXROTH GMBH Effective date: 19951110 |
|
NLR1 | Nl: opposition has been filed with the epo |
Opponent name: MANNESMANN REXROTH GMBH |
|
PLBF | Reply of patent proprietor to notice(s) of opposition |
Free format text: ORIGINAL CODE: EPIDOS OBSO |
|
RDAH | Patent revoked |
Free format text: ORIGINAL CODE: EPIDOS REVO |
|
RDAG | Patent revoked |
Free format text: ORIGINAL CODE: 0009271 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: PATENT REVOKED |
|
GBPR | Gb: patent revoked under art. 102 of the ep convention designating the uk as contracting state |
Free format text: 961017 |
|
27W | Patent revoked |
Effective date: 19961017 |
|
NLR2 | Nl: decision of opposition |