US3854593A - Overload switch-off device for hydraulic lifting or adjusting mechanisms connected in tandem, in particular for hydraulic loading and unloading cranes - Google Patents

Overload switch-off device for hydraulic lifting or adjusting mechanisms connected in tandem, in particular for hydraulic loading and unloading cranes Download PDF

Info

Publication number
US3854593A
US3854593A US00290297A US29029772A US3854593A US 3854593 A US3854593 A US 3854593A US 00290297 A US00290297 A US 00290297A US 29029772 A US29029772 A US 29029772A US 3854593 A US3854593 A US 3854593A
Authority
US
United States
Prior art keywords
hydraulic
switch
pressure
jib
overload
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
US00290297A
Other languages
English (en)
Inventor
S Gross
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Application granted granted Critical
Publication of US3854593A publication Critical patent/US3854593A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • 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
    • 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

Definitions

  • the blocking valves are capable of actuation by one or several control valves which are controlled by magnets that are actuated by means of a circuit closed by jib arm switches and an electrical pressure switch, as a result of which the flow to the hoses for the jib arms of a crane can be effected in such a way that the supply of a pressure medium (oil) to the driving elements for the lift arm, the luffing arm and the telescopic arm is interrupted if the permissible load limit is reached, while alternatively the supply for such operations is blocked which if carried out would cause further loading of the jib arms which are already loaded to their maximum permissible limit.
  • a pressure medium oil
  • a hydraulic loading and unloading crane can carry a greater load with a short crane jib or a small reach than is the case with a longer crane jib or a greater reach.
  • a loading and unloading crane can lift its maximum load when the crane jib is completely retracted.
  • Such an increase of reach may be brought about in different ways, e.g., by extending the extensible part of the crane jib after lifting the load, or, for instance, in the case of a crane jib with articulated top or fly-jib, if the fly-jib is raised after lifting the load or if the crane jib is inclined upward or downward and is adjusted to a more horizontal position while the load is suspended.
  • the measured values (actual values) emanating from the angle detector and the pressure detector are compared in the computer with the design values. At a certain difference of the two values a relay is operated, and the crane is stopped, e.g. with the aid of an electro pneumatic valve.
  • the above-mentioned overload safety systems are relatively expensive to manufacture and to buy, and they are therefore not suitable for hydraulic truck cranes since, as has been shown, the acquisition of an overload safety system costs substantially the same as the crane itself.
  • shut-off valve has become known in which the oil circulation of the pump is short-circuited upstream of the control valves so that no oil can flow into the control valves, if a certain pressure in the lifting cylinder of the crane is exceeded.
  • this arrangement does not always permit of a movement to reduce the load moment, e.g., the telescopic arm can no longer be retracted and the lift arm can no longer be raised. This is however necessary if the lift arm and the luffmg arm are above the horizontal plane passing through the jib articulation point.
  • shut-off valves have become known, which are controlled by the pressure of the lifting cylinder and are installed on the downstream side of the control valve in the feed line leading to the given bydraulic cylinder. These valves block, e.g., the function ofluffing out as well as extension of the telescopic arm, when a certain lifting cylinder pressure is approached.
  • the present invention provides an overload switch-off device for hydraulic lifting or adjusting mechanisms connected in tandem, in partucular for hydraulic loading and unloading cranes, wherein blocking valves intended for blocking sliding spools in a main control valve block are arranged upstream of the latter, said blocking valves being capable of actuation by one or several control valves controlled by magnets that are actuated by means of a circuit closed by jib arm switches and an electrical pressure switch, as a result of which the flow to the hoses for the jib arms of a crane can be effected in such a way that the supply ofa pressure medium (oil) to the driving elements for the lift arm, the luffing arm and the telescopic arm is interrupted if the permissible load limit is reached, while alternatively the supply for such operations is blocked which if carried out would cause further loading of the jib arms which are already loaded to their maximum permissible limit.
  • a pressure medium oil
  • a further characteristic of the invention consists in the fact that one of the blocking valves is preferably connected with the lifting cylinders for the lift arm via auxiliary lines suchas hydraulic hoses of known design.
  • the blocking valves are positively connected with the control valve or valves via pressure lines or the like.
  • each blocking valve has two pistons which block the given sliding spool of the main control valve block. If only one 3-2 control valve is employed, only one of these pistons is required, since in this case blocking takes place only in one direction.
  • FIG. 1 is a diagrammatic presentation of an overload switch-off device in accordance with the invention as applied to a hydraulic loading and unloading crane, and
  • FIG. 2 is a circuit diagram of the device.
  • the pressure in the two lifting cylinders 22 of a crane is characteristic for the load moment and must in any case not exceed a certain value
  • the pressure may be utilised for actuating an electrical pressure switch 29.
  • the d.c. circuit of, e.g., 24 volts is thus closed at the primary point, and the jib arm switches 12, 13, 14 and have a certain closed position depending on the positioning and angular position of the three jib arms 19, and 21 of the crane so that several parallel circuits are formed, each of which actuates a magnet 36 (FIG. 2).
  • Six 3-2 control valves 6 to 11 magnetically actuated in this way allow the pressure medium, which may be hydraulic oil, e.g., from the lifting cylinders 22 or the main oil circuit, or air, e.g., from the brake air storage tank of the truck, to flow to one side or to both sides of three blocking valves 3, 4 or 5.
  • the pressure medium which may be hydraulic oil, e.g., from the lifting cylinders 22 or the main oil circuit, or air, e.g., from the brake air storage tank of the truck, to flow to one side or to both sides of three blocking valves 3, 4 or 5.
  • a sliding spool 1 ofa given control function is blocked in one or in both directions of actuation.
  • the jib arm switches 12, l3, l4 and 15 are arranged at the articulation points between the jib arms 19, 20 and 21 and switch over at a certain angular position.
  • the device proposed by the invention operates in the following manner as shown in FIG. 1:.
  • the connecting line leading to the blocking valve 3, 4 or 5 acts as a leakage oil line.
  • the pressure medium which in the embodiment shown and described is the pressurised oil of the lifting cylinder 22, flows through a pressure hose 16, via the control valves 6 to 11 and via pressure lines 23, 24 and 25 into one or the other side of one of the blocking valves 3 to 5.
  • the blocking valves 3 to 5 as proposed by the invention are designed so as to prevent control of a certain function. This is achieved by a mechanical connection being provided between the sliding spool 1 of a main control valve block 2 and the blocking valve 3, 4 or 5.
  • the mechanical connection can be formed by the sliding spool l'itself or by a control rod with lever transmission.
  • Hoses l7 and 18 convey the pressure medium from the main control valve block 2 to the pressure cylinders for the luffing arm 20 and the telescopic arm 21.
  • FIG. 2 a schematic circuit diagram shows how the device proposed by the invention functions.
  • the characteristic pressure of the lifting cylinder 22 acts on the electrical pressure switch 29.
  • the latter can be so adjusted with the aid of a spring and an adjusting screw as to switch the switch 29 from position A to position B, at a certain pressure.
  • the circuit of a d.c. battery of, e.g., 24 volts is closed.
  • the circuit is further switched to position C or D by the jib arm switch 12.
  • switch position C signifies that column 31 and lift arm 19 form an acute angle.
  • the position D signifies that the lift arm 19 is swung further beyond the horizontal line.
  • the critical switch position thus occurs at the right angle between the column 31 and the lift arm 19.
  • a further arm switch 13 between the lift arm 19 and the luffing arm 20 enables the current in position E to flow to control valve 6 or to control valve 7. In position F both control valves 6 and 7 are connected in parallel.
  • the arm switch 13 is provided because, owing to the possibility of the luffing arm 20 luffing inward, the conditions for blocking of the lift arm 19 in one or the other direction are not so easy to follow.
  • the arm switch 13 causes the circuits to be connected in parallel if the luffing arm 20 is by more than 20 below the extended position of the two arms 19 and 20. Another angle than the angle mentioned above would have been equally suitable as a starting point. The angle depends on the design and should, as far as possible, be so selected that there are no great differences between the load moment in the extended jib position and when the jib is inclined, e.g., by 20.
  • control valve 6 In the zero position of the control valve 6 oil can flow back from the connection 34 via the connection 33 to connection 37 and into a tank 38. What has been said in respect of control valve 6 applies also to control valve 7 if the arm switch 12 is in the position D. In this position, the lift arm lowering function is blocked. Simultaneously with the switching on of the electrical pressure switch 29 the circuit for the control valves 8 or 9, respectively, is released, depending on whether the arm switch 14 is in position H or I.
  • the arm switch 14 is located within the arm system at the tip of the crane, where the load carrying device is connected (see FIG. 1).
  • the position H arises if the direction of the load forms an angle of 90 to 270 with the direction of the luffing arm 20.
  • control valves 8 and 9 are switched on in the same way as the control valves 6 and 7.
  • the above also applies to blocking of the telescopic arm 21 of the crane and to the actuation of the blocking valve 5.
  • the decision as to whether the control valve 10 or 11 is actuated depends on the arm switch which can be arranged at the same point as the arm switch 14, which switches to position J if the angle between the direction of the load and the luffing arm amounts to from 180 to 360.
  • the position K is reached if the luffing arm 20 and the direction of the load form an angle between 0 and 180.
  • further control valves, blocking valves and arm switches can be provided.
  • the arm system comprises more than two jibs additional arm switches capable of being actuated simultaneously must be provided, in accordance with the lift arm function. These arm switches correspond to arm switch 13 which at the same time causes the appropriate control valve 6 to 11 to be blocked in both directions.
  • An overload switch-off arrangement for hydraulic loading and unloading cranes comprising a plurality of jib arms connected in tandem for relative movement with respect to each other; a plurality of hydraulic actuating means, each associated with adjacentjib arms, for moving said adjacent jib arms relative to each other; a
  • said overload switch-off arrangement comprising:
  • a pressure-sensitive switch in at least one of said conduit means and sensitive to a predetermined maximum hydraulic pressure

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Jib Cranes (AREA)
  • Control And Safety Of Cranes (AREA)
  • Fluid-Pressure Circuits (AREA)
US00290297A 1971-12-24 1972-09-19 Overload switch-off device for hydraulic lifting or adjusting mechanisms connected in tandem, in particular for hydraulic loading and unloading cranes Expired - Lifetime US3854593A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2164628A DE2164628C3 (de) 1971-12-24 1971-12-24 Überlastabschalteinrichtung für hintereinandergekoppelte hydraulische Hubbzw. Verstellmechanismen

Publications (1)

Publication Number Publication Date
US3854593A true US3854593A (en) 1974-12-17

Family

ID=5829262

Family Applications (1)

Application Number Title Priority Date Filing Date
US00290297A Expired - Lifetime US3854593A (en) 1971-12-24 1972-09-19 Overload switch-off device for hydraulic lifting or adjusting mechanisms connected in tandem, in particular for hydraulic loading and unloading cranes

Country Status (10)

Country Link
US (1) US3854593A (it)
JP (1) JPS4872842A (it)
AT (1) AT322781B (it)
DE (1) DE2164628C3 (it)
FR (1) FR2164572B1 (it)
GB (1) GB1403199A (it)
IT (1) IT963709B (it)
NL (1) NL7209279A (it)
SE (1) SE379727B (it)
SU (1) SU539518A3 (it)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0007816A1 (en) * 1978-08-02 1980-02-06 Eaton Corporation Method and apparatus for aiding the operation of a crane
US4198857A (en) * 1977-05-13 1980-04-22 Roger Preux Measuring system
US4411368A (en) * 1980-03-21 1983-10-25 Roger Manjot Safety system for hydraulically controlled hoisting apparatus
US4487741A (en) * 1981-11-30 1984-12-11 Westinghouse Electric Corp. Transfer of fuel assemblies
EP0224446A3 (en) * 1985-11-27 1988-07-13 Oil Control S.P.A. A hydraulic load limiting device for hydraulic cranes
US4861224A (en) * 1988-06-14 1989-08-29 Hi-Ranger, Inc. Aerial lift including overload sensing system
US4894849A (en) * 1988-09-30 1990-01-16 Westinghouse Electric Corp. Apparatus and method for transferring nuclear reactor fuel assemblies
US5597080A (en) * 1994-08-02 1997-01-28 Kranco Crane Services, Inc. Snag load protection system for a crane
US6079576A (en) * 1995-12-13 2000-06-27 Liebherr-Werk Ehingen Gmbh Control device for a hoist mechanism of a crane
WO2012109558A1 (en) * 2011-02-10 2012-08-16 Eaton Corporation Load sense control with standby mode in case of overload
CN110332167A (zh) * 2019-07-10 2019-10-15 南通翔骜液压润滑设备有限公司 高精度分流集流阀
US20210229965A1 (en) * 2016-04-25 2021-07-29 Cargotec Patenter Ab Hydraulic crane

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3814265A (en) * 1973-08-20 1974-06-04 Harnischfeger Corp Hydraulic crane control system having means for deactivating control valves when operating limit is exceeded
FR2418766A1 (fr) * 1978-03-01 1979-09-28 Michel Gutierrez Perfectionnement aux appareils de levage a commande hydraulique
FR2478607A1 (fr) * 1980-03-21 1981-09-25 Manjot Roger Systeme de securite pour appareil de levage a commande hydraulique
AT372922B (de) * 1981-09-28 1983-11-25 Voest Alpine Ag Ueberlast-schutzeinrichtung fuer fahrbare ladegeraete
FR2534643B1 (fr) * 1982-10-15 1986-12-26 Bennes Marrel Dispositif controleur d'etat de charge avec limiteur de capacite de couple pour un circuit hydraulique, notamment sur une grue
DE3613870A1 (de) * 1986-04-24 1987-10-29 Mo N Proizv Ob Str Dorozh Mash Einrichtung fuer den ueberlastungs- und kippschutz von hebezeugen
CN104088840B (zh) * 2014-06-29 2016-04-13 南京梅山冶金发展有限公司 折叠式换向阀强制换向装置和使用方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2936847A (en) * 1959-02-02 1960-05-17 Jay M Eitel Mobile lifting equipment with extensible boom structure
US3489294A (en) * 1968-04-25 1970-01-13 Bucyrus Erie Co Load limit control for hoisting equipment
US3645407A (en) * 1970-06-15 1972-02-29 Daniel F Przybylski Overload protector for crane booms

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1532028A (fr) * 1966-07-21 1968-07-05 Grove Mfg Co Dispositif de contrôle de la charge de sécurité pour des appareils de manutention, notamment des grues à flèches

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2936847A (en) * 1959-02-02 1960-05-17 Jay M Eitel Mobile lifting equipment with extensible boom structure
US3489294A (en) * 1968-04-25 1970-01-13 Bucyrus Erie Co Load limit control for hoisting equipment
US3645407A (en) * 1970-06-15 1972-02-29 Daniel F Przybylski Overload protector for crane booms

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4198857A (en) * 1977-05-13 1980-04-22 Roger Preux Measuring system
EP0007816A1 (en) * 1978-08-02 1980-02-06 Eaton Corporation Method and apparatus for aiding the operation of a crane
US4411368A (en) * 1980-03-21 1983-10-25 Roger Manjot Safety system for hydraulically controlled hoisting apparatus
US4487741A (en) * 1981-11-30 1984-12-11 Westinghouse Electric Corp. Transfer of fuel assemblies
EP0224446A3 (en) * 1985-11-27 1988-07-13 Oil Control S.P.A. A hydraulic load limiting device for hydraulic cranes
US4861224A (en) * 1988-06-14 1989-08-29 Hi-Ranger, Inc. Aerial lift including overload sensing system
US4894849A (en) * 1988-09-30 1990-01-16 Westinghouse Electric Corp. Apparatus and method for transferring nuclear reactor fuel assemblies
US5597080A (en) * 1994-08-02 1997-01-28 Kranco Crane Services, Inc. Snag load protection system for a crane
US6079576A (en) * 1995-12-13 2000-06-27 Liebherr-Werk Ehingen Gmbh Control device for a hoist mechanism of a crane
WO2012109558A1 (en) * 2011-02-10 2012-08-16 Eaton Corporation Load sense control with standby mode in case of overload
US20210229965A1 (en) * 2016-04-25 2021-07-29 Cargotec Patenter Ab Hydraulic crane
US11591190B2 (en) * 2016-04-25 2023-02-28 Hiab Ab Hydraulic crane
CN110332167A (zh) * 2019-07-10 2019-10-15 南通翔骜液压润滑设备有限公司 高精度分流集流阀
CN110332167B (zh) * 2019-07-10 2020-11-13 南通翔骜液压润滑设备有限公司 高精度分流集流阀

Also Published As

Publication number Publication date
DE2164628A1 (de) 1973-07-05
SE379727B (it) 1975-10-20
FR2164572B1 (it) 1977-08-26
NL7209279A (it) 1973-06-26
AT322781B (de) 1975-06-10
DE2164628C3 (de) 1978-03-16
GB1403199A (en) 1975-08-28
DE2164628B2 (de) 1977-07-21
SU539518A3 (ru) 1976-12-15
FR2164572A1 (it) 1973-08-03
JPS4872842A (it) 1973-10-01
IT963709B (it) 1974-01-21

Similar Documents

Publication Publication Date Title
US3854593A (en) Overload switch-off device for hydraulic lifting or adjusting mechanisms connected in tandem, in particular for hydraulic loading and unloading cranes
CA2732257C (en) Equalized hydraulic clamp force control
US5058752A (en) Boom overload warning and control system
GB1568599A (en) Automatic jacking system
US4396218A (en) Spreader system for handling containers
CN102701089B (zh) 工程机械及其吊臂的落臂安全控制系统
US4170308A (en) Hydraulic function disconnect means
JP5543741B2 (ja) クレーンの転倒防止装置
US4427121A (en) Hydraulic valve control for aerial book devices
JP2019534831A (ja) 積荷のサイドシフトを積荷荷重に対して可変的に応答させる液圧クランプシステム
US3734326A (en) Variable capacity lift truck
US3455209A (en) Hydraulic control circuit
US11377334B2 (en) Industrial truck with at least one hydraulic mast lift cylinder
GB2078197A (en) Load limiting device
US3630317A (en) Arrangement for stabilization of trucks
US4219121A (en) Safety system for use in association with material handling equipment
US12275625B2 (en) Hydraulic system for an industrial truck
US3371800A (en) Safe load control device for cranes
US3645407A (en) Overload protector for crane booms
US3792780A (en) Mechanism for positioning and restricting crane control levers to prevent dangerous load condition
JPH0257703A (ja) 油圧シリンダの制御方法
US3315820A (en) Crane with winch releasing means
KR20170105978A (ko) 과부하 방지 시스템을 구비한 크레인
US3987906A (en) Apparatus for preventing the tilting of telescopic jib cranes
US3476017A (en) Power-limiting device for a machine provided with two or more working components