EP0139054A1 - Verfahren zum Steuern des Aus- und Einfahrens von mehrstufigen Teleskopauslegern - Google Patents

Verfahren zum Steuern des Aus- und Einfahrens von mehrstufigen Teleskopauslegern Download PDF

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Publication number
EP0139054A1
EP0139054A1 EP83306403A EP83306403A EP0139054A1 EP 0139054 A1 EP0139054 A1 EP 0139054A1 EP 83306403 A EP83306403 A EP 83306403A EP 83306403 A EP83306403 A EP 83306403A EP 0139054 A1 EP0139054 A1 EP 0139054A1
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EP
European Patent Office
Prior art keywords
boom
length
cylinder
detected
boom portion
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.)
Granted
Application number
EP83306403A
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English (en)
French (fr)
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EP0139054B1 (de
Inventor
Jun Fujioka
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.)
Kobe Steel Ltd
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Kobe Steel Ltd
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Filing date
Publication date
Application filed by Kobe Steel Ltd filed Critical Kobe Steel Ltd
Priority to DE8383306403T priority Critical patent/DE3371900D1/de
Priority to EP83306403A priority patent/EP0139054B1/de
Publication of EP0139054A1 publication Critical patent/EP0139054A1/de
Application granted granted Critical
Publication of EP0139054B1 publication Critical patent/EP0139054B1/de
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
    • B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
    • B66C23/62—Constructional features or details
    • B66C23/64—Jibs
    • B66C23/70—Jibs constructed of sections adapted to be assembled to form jibs or various lengths
    • B66C23/701—Jibs constructed of sections adapted to be assembled to form jibs or various lengths telescopic
    • B66C23/705—Jibs constructed of sections adapted to be assembled to form jibs or various lengths telescopic telescoped by hydraulic jacks

Definitions

  • This invention relates to a method for controlling the telescopic extension and contraction of a multistage boom of a crane or the like in an efficient manner.
  • Multistage booms generally used on cranes or the like are of the telescopic type, which has its modulus of section reduced gradually toward the fore ends of the telescopic boom portions and which is designed to extend firstly a boom portion with the largest modulus of section having the greatest boom strength and to contract firstly a boom portion with the smallest modulus of section during the contracting operation. Therefore, -in controlling the extension and contraction of a three stage boom, for example, the ideal procedure is to extend and contract the telescopic boom portions successively, extending the fore boom portion after the intermediate boom portion is fully extended during extrension, and contracting the intermediate boom portion after complete contraction of the fore boom portion during contraction.
  • the former method is costly since it necessitates to provide a take-up reel for winding the electric cables which connect the limit switches to the electromagnetic valve in relation with the telescopic operation of the boom, in addition to the above-mentioned two limit switches for detecting the fully extended state of the intermediate boom portion and the fully contracted state of the distal boom portion, respectively.
  • the latter method has a problem in that it likewise requires provision of costly boom operating cylinders and a complicated hydraulic control circuit.
  • the present invention provides a method for controlling the boom operating cylinders during expansion and contraction of a multistage telescopic boom including a base boom portion, an intermediate boom portion and a fore boom portion, said method 'comprising:
  • the present invention also provides apparatus for controlling the boom operating cylinders during expansion and contraction of a multistage telescopic boom including a base boom portion, an intermediate boom portion and a fore boom portion, said apparatus comprising:
  • FIG. 1 there is shown an example of a multistage (three-stage) boom including a fore boom portion 3 which is telescopically fitted in an intermediate boom portion 2 which is in turn telescopically fitted in a base boom portion 1.
  • a first cylinder 4 for operating the intermediate boom portion 2 is provided between the base and intermediate boom portions 1 and 2
  • a second cylinder for operating the fore boom portion 3 is provided between the base and intermediate and fore boom portions 2 and 3.
  • the first and second cylinders 4 and 5 are sequentially actuated to (a) extend the boom, by switching from the first cylinder 4 to the second cylinder 5 exactly at the point when the intermediate boom portion 2 is fully extended relative to the base boom portion 1 and (b) contact the boom, by switching from the second cylinder 5 to the first cylinder 4 exactly at the point when the fore boom portion 3 is fully contracted relative to the intermediate boom portion 2 as shown by solid line in Figure 1.
  • the actual boom length L at this time point is constant.
  • the boom length detector 6 may comprise a potentiometer which is mounted, via gears, on the axis of a wire winding drum of a spring-loaded wire retractor 6a which thereby measures the length of wire 6b pulled out from the drum when the boom is extended, the front end of the wire 6b being securely fixed to a base end portion of the fore boom member 3.
  • the boom length detector 6 detects the extended boom length with a good degree of accuracy in most cases, but the detected value inevitably contains an error of about plus or minus 10 cm. If the error is expressed by (a), the detected boom length (1) of the boom which has actually a length L when in the position indicated in solid line in Figure 1, is
  • an arbitrary length (b) (eg of 20-50cm) which is greater than the error (a) is preselected to determine a first reference value (L - b) which is the actual length of the boom in the position of Figure 1 minus the preselected value (b), and a second reference value (L + b) which is the actual length L of the boom plus the preselected value (b).
  • the first cylinder 4 alone is actuated to extend or contract only the intermediate boom portion 2 if the detected boom length (1) of the detector 6 is smaller than (L - b) and the second cylinder 5 alone is actuated to extend or contract the fore boom portion 3 if the output value (1) of the detector 6 is greater than (L + b).
  • the switching of the cylinders 4 and 5 is controlled on the basis of the variation per unit time (V) of the detected boom length (1).
  • the boom length or the detected boom length (1) of the boom length detector 6 changes due to the telescopic motion of the boom at a velocity (v) which is expressed by
  • one cylinder which has been in operation comes to the end of its stroke and the telescopic velocity of the boom becomes zero.
  • the cylinders 4 and 5 should be switched when the telescopic velocity becomes zero.
  • the variation per unit time (V) of the detected boom length (1) which represents the telescopic velocity (v) of the boom, need only be detected when the detected boom length (1) of the boom length detector 6 is in the range S between the first reference value (L-b) and the second reference value (L+b).
  • boom extending fluid chambers 4a and 5a of the first and second cylinders 4 and 5 are separately connected to conduits 9 and 10 through counterbalance valves 7 and 8, respectively, and the conduits 9 and 10 are selectively connected to a main conduit 12 by a pilot change-over valve 11.
  • the boom contracting oil chambers 4b and 5b of the first and second cylinders 4 and 5 communicate with each other through an intermediate conduit 13 and are connected to a main circuit 14 in parallel relation with each other.
  • the main circuits 12 and 14 are selectively connectable either to a hydraulic pump P serving as a pressure source or to a tank T by the operation of a boom extension/contraction control valve 15 which switches the flow direction of the pressure medium thereby to extend or contract the cylinders 4 and 5.
  • a boom extension/contraction control valve 15 which switches the flow direction of the pressure medium thereby to extend or contract the cylinders 4 and 5.
  • Indicated at 16 is an operating lever of the control valve 15.
  • the pilot change over valve 11 is connected to an accumulator 18 through an electromagnetic valve 17 which is actuated by an electric change-over signal from an electric control circuit operated according to the logic circuit shown in Figure 4 thereby to supply the pilot pressure from the accumulator 18 to the pilot change over valve 11.
  • the change-over valve 11 is switched to select either the extension or contraction of the cylinder 4 or 5.
  • the control circuit operated according to the logic circuit of Figure 3 receives the detected boom length (1) of the boom length detector 6 as the telescopic boom expands or contracts and compares it with the above mentioned preset first and second reference values (L-b) and (L+b), turning on or off a relay R according to the results of the comparison.
  • the control circuit includes a microprocessor 20 as shown in Figure 4 and the logic circuit of Figure 3 is provided in the form of a programme in the microprocessor 20.
  • a microprocessor which is already provided on the crane for the control of the overload detector system.
  • Such a microprocessor is already supplied with the detected boom length (1) from the boom length detector 6 sequentially at predetermined time intervals, and it can easily perform the operations of comparing the detected boom length (1) with the respective reference values and detecting the variation per unit time of the detected boom length (l), for the on-off control of the relay R, by incorporating a programme corresponding to the logic circuit of Figure 3.
  • the switch Rs is turned on and off according to the on-off control of the relay R to energise and de-energise the solenoid 17', accurately switching the position of the electromagnetic valve 17 of Figure 2.
  • the boom length is short in the initial stage of the boom extension and the detected boom length (1) is smaller than the first reference value (L-b)
  • its signal is fed to a relay-off circuit 26 through a YES circuit of the discriminator 22 to turn off the relay R of Figure 4, de-energising the solenoid 17' and maintaining the electromagnetic valve 17 and the pilot change-over valve 11 in the positions shown in Figure 2. Therefore, the fluid pressure which is fed in the direction of arrow Al is fed in the direction of arrow A2 and admitted into the extending oil chamber 4a of the cylinder 4, while the fluid pressure in the contracting oil chamber 4b of the cylinder 4 is led in the direction of arrow A3 for return to the tank T.
  • the first cylinder 4 extends the intermediate boom portion 2 out of the base boom portion 1.
  • the conduit 9 which is connected to the extending oil chamber 5a of the second cylinder 5 is blocked by the pilot change over valve 11, so that the second cylinder 5 does not extend or contract and the fore boom portion 3 is held in its contracted state in the intermediate boom portion 2 which is being extended out of the base boom portion 1.
  • the detected boom length (1) becomes greater than the first reference value (L-b), so that the detected boom length (1) is fed to the discriminator 23 for comparison with the second reference value (L+b).
  • the detected boom length (1) is still smaller than the second reference value (L+b) at this time and the detected boom length (1) is fed to the discriminator 24 through the NO circuit of the discriminator 23 to determine if the variation (V) of the detected boom length (1) per unit time is greater than a predetermined value.
  • the control treats the discriminator 23 as if it were not included in the control sequence.
  • V variation of the detected boom length (1) exceeds a predetermined value (which means that the first cylinder 4 has not yet reached the end of its stroke)
  • the signal is returned to the initial point of control through the NO circuit of the discriminator 24.
  • the electromagnetic valve 17 and pilot change over valve 11 are continously maintained in the position shown, permitting further extension of the intermediate boom portion 2 by the first cylinder 4 alone.
  • the signal is fed to a relay-on circuit 26 1 through the YES circuit of the discriminator 24, turning on the relay R of Figure 4 and energising the solenoid 17' through the switch Rs to shift the electromagnetic valve 17 to the right position in Figure 2. Consequently, the fluid pressure from the accumulator 18 is led in the direction of arrow A4 to shift the pilot change-over valve 11 into the upper position in the same figure, stopping the supply of fluid pressure to the first cylinder 4 and instead feeding the fluid pressure in the direction A5 from the main circuit 12 for admission into the extending fluid chamber 5a of the second cylinder 5.
  • the fluid pressure in the contracting chamber 5b of the second cylinder 5 is drained in the direction of arrow A6 for return to the tank T.
  • the first cylinder 4 is stopped with the intermediate boom portion 2 held in a fully extended position relative to the base boom portion 1, while the fore boom portion 3 alone is extended out of the intermediate boom portion 2 by the extension of the second cylinder 5.
  • the detected boom length (1) becomes greater than the second reference value (L+b) by further extension of the boom, the detected boom length (1) is fed to the relay-on circuit 26' through the YES circuit of the discriminator 23, holding the electromagnetic valve 17 in the right position in the figure to permit the extension of the fore boom portion 3 by the second cylinder 5 alone.
  • the intermediate boom portion 2 is firstly extended out of the base boom portion 1 by the first cylinder 4, and the electromagnetic valve 17 shifted when the first cylinder 4 comes to its troke end, that is to say, when the intermediate boom portion 2 is fully extended, thereby stretching the second cylinder 2 to extend the fore boom portion 3 out of the intermediate boom portion 2.
  • the fluid pressure flowing in the direction of arrow Bl is fed in the direction of arrow B3 and admitted into the contracting fluid pressure in the extending chamber 5a of the second cylinder 5 is drained in the direction of arrow B4 and returned to the tank T. Consequently, the first cylinder 4 remains without expanding or contracting with the intermediate boom portion 2 in the fully extending state relative to the base boom portionl, so that the fore boom portion only retracts into the intermediate boom portion by the contraction of the second cylinder 5.
  • the detected boom length (1) is fed to the discriminator 24' through the NO circuit of the discriminator 23 to check if the variation per unit time (V) of the detected boom length (1) is greater than a predetermined value. If the variation (V) is greater than the predetermined value (implying that the second cylinder 5 has not yet reached the end of its stroke), the signal is returned to the initial point of control through the NO circuit of the discriminator 24'. Therefore, the electromagnetic valve 17 is retained in the current position, so that the fore boom portion 3 is still retractred by the second cylinder 5.
  • the fluid pressure which is led in the arrowed direction Bl is admitted into the contracting chamber 4b of the first cylinder 4, while the fluid pressure in the extending chamber 4a of the first cylinder 4 is led out in the direction of arrow B5 for return to the tank T.
  • the first cylinder 4 starts to contract to retract the intermediate boom portion 2 into the base boom portion 1, along with the fore boom portion 3 which is held in a fully retracted position in the intermediate boom portion 2.
  • the detected value (1) is fed to the relay-off circuit 26 through the YES circuit of the discriminator 22 1 to hold the electromagnetic valve 17 in the initial position shown, so that the intermediate boom portion 2 is retracted into the base boom portion 1 by the first cylinder 4 along with the fore boom portion 3.
  • the discriminator 24 or 24' of the control circuit of Figure 3 regards that there is no variation (V) in the detected boom length (1) although the operating cylinder has not yet reached the end of its stroke, turning on or off the relay R to shift the electromagnetic valve 17 to the right or left position.
  • the control upon re-starting the telescopic operation of the boom, the control would recommence from the point at which the electromagnetic valve 17 was switched, the cylinder of the next stage extending or contracting the with the cylinder of the prior stage left in a position short of the end of its stroke.
  • the respective cylinders are successively operated by an accurate switching operation to extend or contract a boom in the ideal way.
  • the method can be economically applied since it can utilise a boom length detector which is normally already provided on a multistage boom, without necessitating changes in the construction of the booms and cylinders.
  • the switching function is performed only in a predetermined range before and after a cylinder switching point L without resorting to a mechanical detection mechanism to guarantee accurate control of the switching operation.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Jib Cranes (AREA)
  • Forklifts And Lifting Vehicles (AREA)
EP83306403A 1983-10-21 1983-10-21 Verfahren zum Steuern des Aus- und Einfahrens von mehrstufigen Teleskopauslegern Expired EP0139054B1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE8383306403T DE3371900D1 (en) 1983-10-21 1983-10-21 Method for controlling stretching and contracting operations of telescopic multistage boom
EP83306403A EP0139054B1 (de) 1983-10-21 1983-10-21 Verfahren zum Steuern des Aus- und Einfahrens von mehrstufigen Teleskopauslegern

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP83306403A EP0139054B1 (de) 1983-10-21 1983-10-21 Verfahren zum Steuern des Aus- und Einfahrens von mehrstufigen Teleskopauslegern

Publications (2)

Publication Number Publication Date
EP0139054A1 true EP0139054A1 (de) 1985-05-02
EP0139054B1 EP0139054B1 (de) 1987-06-03

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EP83306403A Expired EP0139054B1 (de) 1983-10-21 1983-10-21 Verfahren zum Steuern des Aus- und Einfahrens von mehrstufigen Teleskopauslegern

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EP (1) EP0139054B1 (de)
DE (1) DE3371900D1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115477239A (zh) * 2022-07-04 2022-12-16 韶关市起重机厂有限责任公司 一种电控实现的起重机顺序伸缩系统

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2761285A (en) * 1953-09-03 1956-09-04 Julian B Beecroft Control system for power-operated moving members
DE2028826A1 (de) * 1970-01-14 1971-07-15 Tadano Iron Works Ausfahreinrichtung fur mehrstufigen Aus leger
US3672257A (en) * 1969-03-17 1972-06-27 Tadano Tekkosho Kk Extension means of a multi-stage boom
DD100691A1 (de) * 1972-12-14 1973-10-05
US3809248A (en) * 1970-02-13 1974-05-07 Tadano Tekkosho Kk Boom extension means
US4125974A (en) * 1977-07-08 1978-11-21 Harnischfeger Corporation Control system for telescopic boom
US4286386A (en) * 1977-09-06 1981-09-01 Long Irvin E Electro-mechanical displacement measuring device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6023080B2 (ja) * 1979-11-16 1985-06-05 株式会社ユニック ブ−ム伸縮装置
JPS5678795A (en) * 1980-10-06 1981-06-27 Unic Corp Successive working cylinder device for multistage expansion boom

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2761285A (en) * 1953-09-03 1956-09-04 Julian B Beecroft Control system for power-operated moving members
US3672257A (en) * 1969-03-17 1972-06-27 Tadano Tekkosho Kk Extension means of a multi-stage boom
DE2028826A1 (de) * 1970-01-14 1971-07-15 Tadano Iron Works Ausfahreinrichtung fur mehrstufigen Aus leger
US3809248A (en) * 1970-02-13 1974-05-07 Tadano Tekkosho Kk Boom extension means
DD100691A1 (de) * 1972-12-14 1973-10-05
US4125974A (en) * 1977-07-08 1978-11-21 Harnischfeger Corporation Control system for telescopic boom
US4286386A (en) * 1977-09-06 1981-09-01 Long Irvin E Electro-mechanical displacement measuring device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115477239A (zh) * 2022-07-04 2022-12-16 韶关市起重机厂有限责任公司 一种电控实现的起重机顺序伸缩系统

Also Published As

Publication number Publication date
DE3371900D1 (en) 1987-07-09
EP0139054B1 (de) 1987-06-03

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