EP0721915B1 - Vorrichtung zum Ermitteln, wann ein Kranarm die höchstzulässige Last trägt - Google Patents

Vorrichtung zum Ermitteln, wann ein Kranarm die höchstzulässige Last trägt Download PDF

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Publication number
EP0721915B1
EP0721915B1 EP19940830575 EP94830575A EP0721915B1 EP 0721915 B1 EP0721915 B1 EP 0721915B1 EP 19940830575 EP19940830575 EP 19940830575 EP 94830575 A EP94830575 A EP 94830575A EP 0721915 B1 EP0721915 B1 EP 0721915B1
Authority
EP
European Patent Office
Prior art keywords
chamber
cursor
cylinder
orifice
pilot conduit
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.)
Expired - Lifetime
Application number
EP19940830575
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English (en)
French (fr)
Other versions
EP0721915A1 (de
Inventor
Andrea Storci
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.)
Oil Control SpA
Original Assignee
Oil Control SpA
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 Oil Control SpA filed Critical Oil Control SpA
Priority to EP19940830575 priority Critical patent/EP0721915B1/de
Priority to DE1994600711 priority patent/DE69400711T2/de
Publication of EP0721915A1 publication Critical patent/EP0721915A1/de
Application granted granted Critical
Publication of EP0721915B1 publication Critical patent/EP0721915B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • B66C23/88—Safety gear
    • B66C23/90—Devices for indicating or limiting lifting moment

Definitions

  • the invention relates specifically but not exclusively to a device for blocking manoeuvring of a crane when a load on said arm reaches a load limit level.
  • the invention especially relates to a device comprising: a) a balance valve, arranged on a hydraulic transmission line of a double-acting cylinder provided with a first chamber on the cylinder base side associated to the raising of a crane arm and a second chamber, on the stem side of the cylinder, associated to the lowering of the arm; b) a first pilot conduit, communicating with the first chamber of the cylinder; c) a second pilot conduit, communicating with the second chamber of the cylinder; d) a cursor, slidingly mobile within a seating and provided on opposite sides with a first end and a second end on which the fluids of the first and second pilot conduits act reciprocally contrastingly, the cursor being pushed into a block position whereat it activates a cylinder block actuator by effect of the action of the fluid of the first pilot conduit; e) a spring, acting on the cursor contrastingly to the action of the fluid in the first pilot conduit.
  • the device is thus constructionally complicated and expensive, as both the cursor and the seat must be made to extreme levels of precision and further are only suitable for a cylinder having a predetermined stem-piston size rapport.
  • One advantage of the invention is that it can be practically applied without any special modifications to cranes at present in use.
  • figure 1 schematically shows the device applied to a crane.
  • a double-acting cylinder 3 is provided with a first chamber 3a on the cylinder base side, which first chamber 3a is associated to the raising of the arm 2 and is further provided with a second chamber 3b on the stem side, which second chamber 3b is associated to the lowering of the arm 2.
  • a balance valve 14 is arranged on a hydraulic drive line 15 of the double-acting cylinder 3, which hydraulic drive line 15 comprises a pump 16 and a distributor 17.
  • the device comprises a first pilot conduit 4 communicating with the first chamber 3a and a second pilot conduit 5 communicating with the second chamber 3b.
  • the device further comprises a cursor 6 which is slidingly mobile in a constant-section seating 8 and which is provided with a first end 6a and a second end 6b, on which the fluids of respectively the first and the second pilot conduits 4 and 5 act in reciprocal contrast.
  • the surface areas of the ends 6a and 6b which the fluids act upon are identical.
  • a spring 9 acts on the cursor 6 in contrast to the action of the fluid of the first pilot conduit 4.
  • the device comprises a drainage conduit 10, which communicates with a discharge 13 and with the second end 6b of the cursor 6.
  • a first and a second orifice 11 and 12 are provided, each having a predetermined diameter section, which are arranged respectively on the second pilot conduit 5 and on the drainage conduit 10. Thanks to the two orifices 11 and 12 the fluid pressure acting on the second end 6b is comprised between the external pressure of the discharge 13 and the pressure in the second chamber 3b. The value of this intermediate presure depends on the orifice sections. The orifices give rise to bleeding, by means of which a pressure acting on the second end 6b is always proportional to the pressure in the second chamber 3b.
  • the passage sections of the orifices 11 and 12 are such that to an increase in pressure in the first chamber 3a of the cylinder, caused by a proportional increase in the second chamber 3b due to the need to pilot the balance valve 14 during an arm lowering operation, corresponds an equal increase in the pressure of the fluid acting on the second end 6b.
  • the orifices 11 and 12 are conformed such that the pressure acting on the second end 6b is porportional to the pressure in the second chamber 3b in accordance with the relation between the area of the cylinder piston on the stem side and the area of the same piston on the base side.
  • An advantage of the invention is that it uses a simple concept, that of a cursor and a seating in which said cursor runs.
  • a further advantage of the invention is that the cursor runs in a constant-section seating with almost negligible friction.
  • the device can be advantageously applied on existing-type cranes, whatever the cylinder stem/piston size relation might be. When the relation changes it is sufficient to modify the relation between the passage sections of the orifices 11 and 12, leaving the cursor 6 unvaried.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Jib Cranes (AREA)

Claims (3)

  1. Vorrichtung zum Ermitteln, wann ein Kranarm die höchstzulässige Last trägt, enthaltend:
    ein Ausgleichsventil (14), an einer hydraulischen Förderleitung (15) eines zweifachwirkenden Zylinders (3) angeordnet, der zum Heben eines Kranarms mit einer ersten Kammer (3a) auf einer Grundseite des zweifachwirkenden Zylinders (3) versehen ist, und zum Absenken des Kranarms mit einer zweiten Kammer (3b) auf der Schaftseite des zweifachwirkenden Zylinders (3) versehen ist;
    eine erste Steuerleitung (4), in Verbindung stehend mit der ersten Kammer (3a) des zweifachwirkenden Zylinders (3);
    eine zweite Steuerleitung (5), in Verbindung stehend mit der zweiten Kammer (3b) des zweifachwirkenden Zylinders (3);
    einen Steuerkolben (6), der in einem Sitz (8) verschiebbar beweglich ist und der ein erstes Ende (6a) und ein gegenüberliegendes zweites Ende (6b) aufweist, wobei Fluide der ersten Steuerleitung (4) und der zweiten Steuerleitung (5) auf das erste Ende (6a) und auf das zweite Ende (6b) eine gegensätzliche Wechselwirkung ausüben; der Steuerkolben (6) in eine Sperrstellung gedrückt wird, in welcher er einen Zylindersperrtrieb (7) aktiviert infolge einer Wirkung des Fluids der ersten Steuerleitung (4);
    eine gegensätzlich zu der Wirkung des Fluids in der ersten Steuerleitung (4) auf den Steuerkolben (6) wirkende Feder (9);
    dadurch gekennzeichnet, daß:
    sie weiterhin eine Dränageleitung (10) aufweist, die in Verbindung mit einem Abfluß (13) und mit dem zweiten Ende (6b) des Steuerkolbens (6) steht;
    eine erste Öffnung (11) und eine zweite Öffnung (12) jeweils an der zweiten Steuerleitung (5) und an der Dränageleitung (10) vorgesehen sind, wobei jedes der ersten Öffnung (11) und zweiten Öffnung (12) einen vorbestimmten Durchmesserquerschnitt aufweist.
  2. Vorrichtung nach Anspruch 1, dadurch gekennzeichnet, daß:
    das erste Ende (6a) und das zweite Ende (6b), auf welche die Fluide wirken, identische Oberflächenbereiche aufweisen; die erste Öffnung (11) und die zweite Öffnung (12) Durchflußquerschnitte aufweisen, die derart ausgebildet sind, daß ein Druckanstieg in der ersten Kammer (3a) des Zylinders, der durch einen proportionalen Anstieg in der zweiten Kammer (3b) zum Steuern des Ausgleichsventils (14) während einer Absenkphase des Kranarms (2) hervorgerufen wird, einer gleichen Druckerhöhung des auf das zweite Ende (6b) wirkenden Fluids entspricht.
  3. Vorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß:
    der Steuerkolben (6) eine Verteilung einer Fluidflußrate auf drei mit dem Sitz (8) verbundenen Rohrleitungen regelt, wobei eine erste Rohrleitung (T) der drei Rohrleitungen mit dem Anfluß (13) verbunden ist, eine zweite Rohrleitung (S) der drei Rohrleitungen mit dem Hydrauliksperrtrieb (7) verbunden ist und eine dritte Rohrleitung (P) der drei Rohrleitungen mit der ersten Kammer (3a) des Zylinders verbunden ist;
    wenn sich der Steuerkolben (6) in der Sperrstellung befindet, die besagte zweite Rohrleitung (3) mit der besagten dritten Rohrleitung (P) in Verbindung gebracht wird.
EP19940830575 1994-12-14 1994-12-14 Vorrichtung zum Ermitteln, wann ein Kranarm die höchstzulässige Last trägt Expired - Lifetime EP0721915B1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP19940830575 EP0721915B1 (de) 1994-12-14 1994-12-14 Vorrichtung zum Ermitteln, wann ein Kranarm die höchstzulässige Last trägt
DE1994600711 DE69400711T2 (de) 1994-12-14 1994-12-14 Vorrichtung zum Ermitteln, wann ein Kranarm die höchstzulässige Last trägt

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19940830575 EP0721915B1 (de) 1994-12-14 1994-12-14 Vorrichtung zum Ermitteln, wann ein Kranarm die höchstzulässige Last trägt

Publications (2)

Publication Number Publication Date
EP0721915A1 EP0721915A1 (de) 1996-07-17
EP0721915B1 true EP0721915B1 (de) 1996-10-09

Family

ID=8218594

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19940830575 Expired - Lifetime EP0721915B1 (de) 1994-12-14 1994-12-14 Vorrichtung zum Ermitteln, wann ein Kranarm die höchstzulässige Last trägt

Country Status (2)

Country Link
EP (1) EP0721915B1 (de)
DE (1) DE69400711T2 (de)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD70981A (de) *
DE1926236B2 (de) * 1969-05-22 1971-07-08 Druckmesseinrichtung fuer hydraulisch beaufschlagte arbeitszylinder, insbesondere fuer auslegerstuetzzylin der an auslegerkranen
DE2629578C2 (de) * 1976-07-01 1985-08-22 Hydrostandard GmbH & Co KG, 5620 Velbert Meßanordnung zur Messung einer hydraulisch abgestützten Last

Also Published As

Publication number Publication date
DE69400711T2 (de) 1997-02-13
EP0721915A1 (de) 1996-07-17
DE69400711D1 (de) 1996-11-14

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