WO2000055435A1 - Arrangement for lifting or lowering a crane jib or the like in an excavator or similar lifting apparatus - Google Patents
Arrangement for lifting or lowering a crane jib or the like in an excavator or similar lifting apparatus Download PDFInfo
- Publication number
- WO2000055435A1 WO2000055435A1 PCT/FI2000/000203 FI0000203W WO0055435A1 WO 2000055435 A1 WO2000055435 A1 WO 2000055435A1 FI 0000203 W FI0000203 W FI 0000203W WO 0055435 A1 WO0055435 A1 WO 0055435A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- cylinder
- pressure
- lifting
- weight
- relieving
- 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.)
- Ceased
Links
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
- B66C23/62—Constructional features or details
- B66C23/82—Luffing gear
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F3/00—Dredgers; Soil-shifting machines
- E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
- E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
- E02F3/30—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with a dipper-arm pivoted on a cantilever beam, i.e. boom
- E02F3/32—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with a dipper-arm pivoted on a cantilever beam, i.e. boom working downwardly and towards the machine, e.g. with backhoes
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F3/00—Dredgers; Soil-shifting machines
- E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
- E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
- E02F3/36—Component parts
- E02F3/42—Drives for dippers, buckets, dipper-arms or bucket-arms
- E02F3/425—Drive systems for dipper-arms, backhoes or the like
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2217—Hydraulic or pneumatic drives with energy recovery arrangements, e.g. using accumulators, flywheels
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2221—Control of flow rate; Load sensing arrangements
-
- 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
- F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
- F15B1/02—Installations or systems with accumulators
-
- 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
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/08—Characterised by the construction of the motor unit
- F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
- F15B15/1423—Component parts; Constructional details
- F15B15/1466—Hollow piston sliding over a stationary rod inside the cylinder
Definitions
- the object of the invention is to provide an arrangement in which, on the one hand, the lifting cylinder proper and the weight-relieving cylinder can be fitted in a simple manner to both new lifting apparatuses being manufactured and also to already existing lifting apparatuses without making any great structural changes to the mechanical structures of the lifting apparatus, and in which, on the other hand, can be utilised, essentially as such, the already existing hydraulic systems used for lifting or lowering the crane jib of a lifting apparatus.
- the lifting cylinder comprises a first cylinder space bordered by the main cylinder, the main piston and the rod of the main piston, a second cylinder space bordered by the main cylinder and the main piston, and a third cylinder space provided inside the hollow rod of the main piston, in which cylinder space is a fixed auxiliary piston extending inside the rod of the main piston, the first cylinder space of the said lifting cylinder being connected to a pressure medium circuit effecting the lowering of the crane jib of the lifting apparatus, the second cylinder space of the lifting cylinder being connected to a pressure accumulator, whereby the said second cylinder space forms a weight-relieving cylinder, and the third cylinder space of the lifting cylinder being connected to the pressure medium circuit effecting the lifting of the crane jib of the lifting apparatus.
- Figure 1 shows an excavator 1 in which is arranged a pressure medium operated lifting cylinder 3 for lifting or lowering the crane jib 2, by means of which lifting cylinder is lifted a load.
- the load consists of a useful load proper to be lifted, and of a base load, comprised of parts belonging to the excavator 1 itself which are to be lifted and lowered, to be lifted together with the useful load.
- the total lift obtained by means of the lifting cylinder 3 is formed as a combined effect of the forces generated by the second and third cylinder spaces II, III.
- the pressure of the weight-relieving cylinder II can be regulated so as to be optimal for each jib 2, respectively, which means that there will not arise a situation where also the lowering of the jib 2 would have to take place by means of hydraulic movement (cylinder space I).
- the effective surface area of cylinder space II is larger than the corresponding surface area in cylinder space III. For this reason it is most advantageous to arrange cylinder space II as the weight-relieving cylinder, because the force required for lifting the useful load is substantially smaller than the force required for lifting the jib 2 of the lifting apparatus 1 and corresponding parts which are lifted and lowered up and down. Due to the said area ratios, also the operating speed of the lifting apparatus 1 is greater when cylinder space III is connected to the hydraulics of the lifting apparatus 1.
- the pressure accumulator 9 consists of a piston-type pressure accumulator, the pistons of which have, in addition, been dimensioned in such a way that the pressure accumulator acts as a pressure-increasing means.
- the low-pressure side 11 of the pressure accumulator 9 is connected to a pressure source 12, for example, to a pressure vessel containing nitrogen.
- a pressure regulating valve 13 by means of which it is also possible to regulate the pressure of the weight-relieving cylinder II and thus the force generated by the weight-relieving cylinder 2.
- a depressurisation valve 16 for discharging pressure from weight-relieving cylinder II and from the side 17 of the pressure accumulator 9 on the weight-relieving cylinder II side, in order that pressure can be discharged when the lifting apparatus 1 is stopped.
- a depressurisation valve 18 for discharging pressure from weight-relieving cylinder II only, which makes possible the fact that by supplying the pressure to cylinder space I, the crane jib 2 can be pressed down and thus the lifting apparatus 1 itself can be raised.
- a branch line 20 provided with a backflow valve 19 for supplying the initial pressure to the pressure medium line 14.
- the pressure can be obtained, for example, by means of the pressure generated by the first lifting taking place after the start-up of the lifting apparatus.
- the cooling system 21 which may consist of, for example, the lifting apparatus' 1 own cooling system.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Jib Cranes (AREA)
Abstract
The invention relates to an arrangement for lifting or lowering a crane jib (2) or the like in an excavator or similar lifting apparatus (1), in which a load is lifted by means of a pressure medium operated lifting cylinder (3), the load consisting of a useful load proper to be lifted, and of a base load, comprised of parts belonging to the apparatus (1) itself which are to be lifted and lowered, to be lifted together with the useful load, in addition to which is provided a weight-relieving cylinder (II), which is arranged to charge a pressure accumulator (9) when the crane jib (2) is being lowered and correspondingly to discharge the pressure accumulator (9) when the crane jib is being lifted. The lifting cylinder (3) comprises a first cylinder space (I) bordered by the main cylinder (4), the main piston (5) and the rod (6) of the main piston, a second cylinder space (II) bordered by the main cylinder (4) and the main piston (5), and a third cylinder space (III) provided inside the hollow rod (6) of the main piston (5), in which cylinder space is a fixed auxiliary piston (7) extending inside the rod (6) of the main piston (5), the first cylinder space (I) of the said lifting cylinder (3) being connected to a pressure medium circuit (8) effecting the lowering of the crane jib (2) of the lifting apparatus (1), the second cylinder space (II) of the lifting cylinder (3) being connected to a pressure accumulator (9), whereby the said second cylinder space (II) forms a weight-relieving cylinder, and the third cylinder space (III) of the lifting cylinder (3) being connected to the pressure medium circuit (10) effecting the lifting of the crane jib (2) of the lifting apparatus (1).
Description
Arrangement for lifting or lowering a crane jib or the like in an excavator or similar lifting apparatus
The invention relates to an arrangement for lifting or lowering a crane jib or the like in an excavator or similar lifting apparatus, in which a load is lifted by means of a pressure medium operated lifting cylinder, the load consisting of a useful load proper to be lifted, and of a base load, comprised of parts belonging to the apparatus itself which are to be lifted and lowered, to be lifted together with the useful load, in addition to which is provided a weight-relieving cylinder, which is arranged to charge a pressure accumulator when the crane jib is being lowered and correspondingly to discharge the pressure accumulator when the crane jib is being lifted.
This type of arrangement is known from the publication WO 97/16371 which shows a hydraulically operated lifting apparatus, in which lifting is carried out by means of an articulated jib. In this type of lifting apparatus, energy is used for lifting the jib in addition to lifting the useful load. To reduce the energy used for lifting the jib, in the solution relating to the reference publication, a separate auxiliary cylinder acting as a weight-relieving cylinder is provided in addition to the lifting cylinder proper, the auxiliary cylinder being connected to a pressure accumulator, in which energy is stored when the jib is lowered, the energy being for the most part available for use when the jib is lifted again.
Fitting the type of auxiliary cylinder described above to a lifting apparatus incurs considerable expenses due to the courses and structures of the apparatus, and installing this type of an additional cylinder, especially to apparatuses already in use, is often even completely impossible.
The object of the invention is to provide an arrangement in which, on the one hand, the lifting cylinder proper and the weight-relieving cylinder can be fitted in a simple manner to both new lifting apparatuses being manufactured and also to already existing lifting apparatuses without making any great structural changes to the mechanical structures of the lifting apparatus, and in which, on
the other hand, can be utilised, essentially as such, the already existing hydraulic systems used for lifting or lowering the crane jib of a lifting apparatus.
To achieve this object, it is characteristic of the arrangement relating to the invention that the lifting cylinder comprises a first cylinder space bordered by the main cylinder, the main piston and the rod of the main piston, a second cylinder space bordered by the main cylinder and the main piston, and a third cylinder space provided inside the hollow rod of the main piston, in which cylinder space is a fixed auxiliary piston extending inside the rod of the main piston, the first cylinder space of the said lifting cylinder being connected to a pressure medium circuit effecting the lowering of the crane jib of the lifting apparatus, the second cylinder space of the lifting cylinder being connected to a pressure accumulator, whereby the said second cylinder space forms a weight-relieving cylinder, and the third cylinder space of the lifting cylinder being connected to the pressure medium circuit effecting the lifting of the crane jib of the lifting apparatus.
Further preferable developments of the invention are disclosed in the dependent claims.
The invention is described in greater detail below with reference to the appended drawings, in which
Figure 1 shows the arrangement relating to the invention when applied to an excavator.
Figure 2 shows the circuit diagram of the arrangement relating to the invention.
Figure 1 shows an excavator 1 in which is arranged a pressure medium operated lifting cylinder 3 for lifting or lowering the crane jib 2, by means of which lifting cylinder is lifted a load. The load consists of a useful load proper to be lifted, and of a base load, comprised of parts belonging to the excavator 1
itself which are to be lifted and lowered, to be lifted together with the useful load.
Instead of using a conventional double-acting hydraulic cylinder, the solution relating to the invention uses a special cylinder 3 known as such, which has three separate cylinder spaces I, II, III.
The lifting cylinder 3 in question is of a type known as such, where the cylinder spaces are formed as follows. The space bordered by the main cylinder 4, the main piston 5 and the rod 6 of the main piston form the first cylinder space I. The second space bordered by the main cylinder 4 and the main piston 5 forms the second cylinder space II. Inside the hollow rod 6 of the main piston 5 is provided a third cylinder space III, in which cylinder space is a fixed auxiliary piston 7 extending inside the rod 6 of the main piston 5.
The first cylinder space I of the lifting cylinder 3 is connected to the pressure medium circuit 8 effecting the lowering of the crane jib 2 of the lifting apparatus 1. The second cylinder space II of the lifting cylinder 3 is connected to the pressure accumulator marked generally with reference numeral 9, whereby the said second cylinder space II forms a weight-relieving cylinder. The third cylinder space III of the lifting cylinder 3 is connected to the pressure medium circuit 10 effecting the lifting of the crane jib 2 of the lifting apparatus 1.
The total lift obtained by means of the lifting cylinder 3 is formed as a combined effect of the forces generated by the second and third cylinder spaces II, III.
The force generated by the lifting cylinder 3 must be limited to a certain value to guarantee the durability of the structures. In the solution relating to the invention this is preferably carried out in such a way that the pressure of the weight-relieving cylinder II is limited by means of a pressure-limiting valve 15 arranged in a pressure medium line 14 between the weight-relieving cylinder II and the pressure accumulator 9.
Due to this arrangement, the total lift of the lifting cylinder 3 can be limited in a simple manner without having to in any way interfere with the means regulating the hydraulic pressure of the lifting apparatus 1 itself. The pressure of the working hydraulics of the lifting apparatus 1 can be utilised in full since the total force of the lifting cylinder 3 has been limited by means of the pressure-limiting valve 15 of the weight-relieving cylinder II.
By using different kinds of jibs 2, the pressure of the weight-relieving cylinder II can be regulated so as to be optimal for each jib 2, respectively, which means that there will not arise a situation where also the lowering of the jib 2 would have to take place by means of hydraulic movement (cylinder space I).
The effective surface area of cylinder space II is larger than the corresponding surface area in cylinder space III. For this reason it is most advantageous to arrange cylinder space II as the weight-relieving cylinder, because the force required for lifting the useful load is substantially smaller than the force required for lifting the jib 2 of the lifting apparatus 1 and corresponding parts which are lifted and lowered up and down. Due to the said area ratios, also the operating speed of the lifting apparatus 1 is greater when cylinder space III is connected to the hydraulics of the lifting apparatus 1.
If, on the other hand, cylinder space III were to be arranged as a weight- relieving cylinder, both the hydraulic pressure of the lifting apparatus 1 and the pressure of the weight-relieving cylinder would have to be limited separately. Furthermore, the weight relieving would affect a smaller part of the total load than if cylinder space II were used as a weight-relieving cylinder. Also in the case that a separate auxiliary cylinder known from the prior art and acting as a weight-relieving cylinder were used, the regulation of the hydraulic pressure of the lifting apparatus 1 would have to be arranged separately.
In the embodiment of the invention shown in Figure 2, the pressure accumulator 9 consists of a piston-type pressure accumulator, the pistons of which have, in addition, been dimensioned in such a way that the pressure
accumulator acts as a pressure-increasing means. The low-pressure side 11 of the pressure accumulator 9 is connected to a pressure source 12, for example, to a pressure vessel containing nitrogen.
Between the pressure source 12 and the pressure accumulator 9 is arranged a pressure regulating valve 13 by means of which it is also possible to regulate the pressure of the weight-relieving cylinder II and thus the force generated by the weight-relieving cylinder 2.
In the pressure medium line 14 between the weight-relieving cylinder II and the pressure accumulator 9 is arranged a depressurisation valve 16 for discharging pressure from weight-relieving cylinder II and from the side 17 of the pressure accumulator 9 on the weight-relieving cylinder II side, in order that pressure can be discharged when the lifting apparatus 1 is stopped.
In the pressure medium line 14 between the weight-relieving cylinder II and the pressure accumulator 9 is in addition arranged a depressurisation valve 18 for discharging pressure from weight-relieving cylinder II only, which makes possible the fact that by supplying the pressure to cylinder space I, the crane jib 2 can be pressed down and thus the lifting apparatus 1 itself can be raised.
In the pressure medium Iine14 between the weight-relieving cylinder II and the pressure accumulator 9 is in addition arranged a branch line 20 provided with a backflow valve 19 for supplying the initial pressure to the pressure medium line 14. The pressure can be obtained, for example, by means of the pressure generated by the first lifting taking place after the start-up of the lifting apparatus.
To cool down the pressure accumulator 9, it is preferably connected to the cooling system 21 which may consist of, for example, the lifting apparatus' 1 own cooling system.
Claims
1. An arrangement for lifting or lowering a crane jib (2) or the like in an excavator or similar lifting apparatus (1 ), in which a load is lifted by means of a pressure medium operated lifting cylinder (3), the load consisting of a useful load proper to be lifted, and of a base load, comprised of parts belonging to the apparatus (1 ) itself which are to be lifted and lowered, to be lifted together with the useful load, in addition to which is provided a weight-relieving cylinder (II), which is arranged to charge a pressure accumulator (9) when the crane jib (2) is being lowered and correspondingly to discharge the pressure accumulator (9) when the crane jib is being lifted, the lifting cylinder (3) comprises a first cylinder space (I) bordered by the main cylinder (4), the main piston (5) and the rod (6) of the main piston, a second cylinder space (II) bordered by the main cylinder (4) and the main piston (5), and a third cylinder space (III) provided inside the hollow rod (6) of the main piston (5), in which cylinder space is a fixed auxiliary piston (7) extending inside the rod (6) of the main piston (5), characterised in that the first cylinder space (I) of the said lifting cylinder (3) being connected to a pressure medium circuit (8) effecting the lowering of the crane jib (2) of the lifting apparatus (1 ), that the second cylinder space (II) of the lifting cylinder (3) being connected to a pressure accumulator (9), whereby the said second cylinder space (II) forms a weight-relieving cylinder, that the third cylinder space (III) of the lifting cylinder (3) being connected to the pressure medium circuit (10) effecting the lifting of the crane jib (2) of the lifting apparatus (1 ), and that in the pressure medium line (14) between the weight- relieving cylinder (II) and the pressure accumulator (9) is arranged a pressure- limiting valve (15).
2. An arrangement as claimed in claim 1 , characterised in that the pressure accumulator (9) is provided with pressure-increasing means.
3. An arrangement as claimed in claim 2, characterised in that the low- pressure side (11 ) of the pressure accumulator (9) is connected to a pressure source (12), most preferably to a pressure vessel.
4. An arrangement as claimed in claim 3, characterised in that between the pressure source (12) and the pressure accumulator (9) is arranged a pressure regulating valve (13).
5. An arrangement as claimed in claim 1 , characterised in that in the pressure medium line (14) between the weight-relieving cylinder (II) and the pressure accumulator (9) is arranged a depressurisation valve (16) for discharging pressure from the weight-relieving cylinder (II) and from the side (17) of the pressure accumulator (9) on the weight-relieving cylinder (n) side.
6. An arrangement as claimed in claim 1 , characterised in that in the pressure medium line (14) between the weight-relieving cylinder (II) and the pressure accumulator (9) is in addition arranged a depressurisation valve (18) for discharging pressure from the weight-relieving cylinder (II).
7. An arrangement as claimed in claim 1 , characterised in that in the pressure medium line (14) between the weight-relieving cylinder (II) and the pressure accumulator (9) is arranged a branch line (20) provided with a backflow valve (19) for supplying the initial pressure to the pressure medium line (14).
8. An arrangement as claimed in claim 1 , characterised in that the pressure accumulator (9) is connected to a cooling system (21 ).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI990609 | 1999-03-18 | ||
| FI990609A FI990609A7 (en) | 1999-03-18 | 1999-03-18 | Arrangement for raising and lowering a boom or similar on an excavator or similar lifting device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2000055435A1 true WO2000055435A1 (en) | 2000-09-21 |
Family
ID=8554231
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/FI2000/000203 Ceased WO2000055435A1 (en) | 1999-03-18 | 2000-03-15 | Arrangement for lifting or lowering a crane jib or the like in an excavator or similar lifting apparatus |
Country Status (2)
| Country | Link |
|---|---|
| FI (1) | FI990609A7 (en) |
| WO (1) | WO2000055435A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103964326A (en) * | 2014-05-05 | 2014-08-06 | 中联重科股份有限公司 | Suspension arm bearing device, suspension arm bearing system and crane |
| EP3438469A1 (en) * | 2017-08-04 | 2019-02-06 | Robert Bosch GmbH | Pivot arm device and bridge |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4046270A (en) * | 1974-06-06 | 1977-09-06 | Marion Power Shovel Company, Inc. | Power shovel and crowd system therefor |
| FR2548242A2 (en) * | 1980-05-28 | 1985-01-04 | Poclain Sa | Earth working machine, particularly such as a hydraulic shovel |
| JPS60250128A (en) * | 1984-05-25 | 1985-12-10 | Mitsubishi Heavy Ind Ltd | Liquid pressure regenerative circuit |
| SE455498B (en) * | 1986-04-28 | 1988-07-18 | Bt Ind Ab | HYDRAULIC LIFTING DEVICE FOR LIFTING UNIT |
| JPH0336333A (en) * | 1989-06-30 | 1991-02-18 | Komatsu Ltd | Potential energy recovery and regeneration device for hydraulic excavators |
| US5778669A (en) * | 1994-12-21 | 1998-07-14 | Kubik; Philip A. | Hydraulic positioning system with internal counterbalance |
-
1999
- 1999-03-18 FI FI990609A patent/FI990609A7/en unknown
-
2000
- 2000-03-15 WO PCT/FI2000/000203 patent/WO2000055435A1/en not_active Ceased
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4046270A (en) * | 1974-06-06 | 1977-09-06 | Marion Power Shovel Company, Inc. | Power shovel and crowd system therefor |
| FR2548242A2 (en) * | 1980-05-28 | 1985-01-04 | Poclain Sa | Earth working machine, particularly such as a hydraulic shovel |
| JPS60250128A (en) * | 1984-05-25 | 1985-12-10 | Mitsubishi Heavy Ind Ltd | Liquid pressure regenerative circuit |
| SE455498B (en) * | 1986-04-28 | 1988-07-18 | Bt Ind Ab | HYDRAULIC LIFTING DEVICE FOR LIFTING UNIT |
| JPH0336333A (en) * | 1989-06-30 | 1991-02-18 | Komatsu Ltd | Potential energy recovery and regeneration device for hydraulic excavators |
| US5778669A (en) * | 1994-12-21 | 1998-07-14 | Kubik; Philip A. | Hydraulic positioning system with internal counterbalance |
Non-Patent Citations (1)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103964326A (en) * | 2014-05-05 | 2014-08-06 | 中联重科股份有限公司 | Suspension arm bearing device, suspension arm bearing system and crane |
| EP3438469A1 (en) * | 2017-08-04 | 2019-02-06 | Robert Bosch GmbH | Pivot arm device and bridge |
Also Published As
| Publication number | Publication date |
|---|---|
| FI990609A7 (en) | 2000-09-19 |
| FI990609A0 (en) | 1999-03-18 |
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