EP0442860A1 - Maschine zum Zerstören von Betonoberflächen - Google Patents

Maschine zum Zerstören von Betonoberflächen Download PDF

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Publication number
EP0442860A1
EP0442860A1 EP91870005A EP91870005A EP0442860A1 EP 0442860 A1 EP0442860 A1 EP 0442860A1 EP 91870005 A EP91870005 A EP 91870005A EP 91870005 A EP91870005 A EP 91870005A EP 0442860 A1 EP0442860 A1 EP 0442860A1
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EP
European Patent Office
Prior art keywords
pressure
hammer
accumulator
pump
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.)
Withdrawn
Application number
EP91870005A
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English (en)
French (fr)
Inventor
Erwin Alfons Virginie Vereecken
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.)
W EVERAERT PVBA
Original Assignee
W EVERAERT PVBA
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 W EVERAERT PVBA filed Critical W EVERAERT PVBA
Publication of EP0442860A1 publication Critical patent/EP0442860A1/de
Withdrawn legal-status Critical Current

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    • 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
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
    • E01C23/00—Auxiliary devices or arrangements for constructing, repairing, reconditioning, or taking-up road or like surfaces
    • E01C23/06—Devices or arrangements for working the finished surface; Devices for repairing or reconditioning the surface of damaged paving; Recycling in place or on the road
    • E01C23/12—Devices or arrangements for working the finished surface; Devices for repairing or reconditioning the surface of damaged paving; Recycling in place or on the road for taking-up, tearing-up, or full-depth breaking-up paving, e.g. sett extractor
    • E01C23/122—Devices or arrangements for working the finished surface; Devices for repairing or reconditioning the surface of damaged paving; Recycling in place or on the road for taking-up, tearing-up, or full-depth breaking-up paving, e.g. sett extractor with power-driven tools, e.g. oscillated hammer apparatus
    • E01C23/124—Devices or arrangements for working the finished surface; Devices for repairing or reconditioning the surface of damaged paving; Recycling in place or on the road for taking-up, tearing-up, or full-depth breaking-up paving, e.g. sett extractor with power-driven tools, e.g. oscillated hammer apparatus moved rectilinearly, e.g. road-breaker apparatus with reciprocating tools, with drop-hammers

Definitions

  • the present invention relates to a machine for breaking concrete surfaces, which machine comprises at least one pounder hammer mounted on a movable frame, a diesel engine, a hydraulic oil tank, a hydraulic pump which supplies oil. under pressure via a pressure circuit to at least one hydraulic cylinder, a system of pulleys attached to the ends of each hydraulic cylinder to lift each hammer hammer with a speed multiplied several times but with a lower force, which is then released as soon as the cylinders are connected without pressure to the oil tank, so that the force of the cylinders on each pulley fades and the hammer-drums make a movement which ends in an impact on the surface to be broken.
  • the invention also relates to a method for operating the machine described above.
  • the machine can be used to break up concrete surfaces which are reinforced or not by an iron reinforcement, such as concrete pavements or concrete coverings.
  • the machine makes it possible to break hard surfaces into small pieces so that they can be cleared easily, for example using a hydraulic excavator.
  • This machine only includes a single pounder hammer actuated by a pulley system mounted on a hydraulic cylinder.
  • the hydraulic system includes an oil tank, a pump, a three-position slide valve, a hydraulic cylinder and a pressure relief valve connected together by high pressure lines. When the slide valve is in the middle position, the flow of the pump flows again without pressure to the tank, while the conduit to the cylinder is closed, so that the weight is suspended motionless on the cable.
  • Automatic succession of strokes is obtained by controlling the slide valve using a separate hydraulic circuit working under low pressure.
  • This circuit includes a separate pump and a reversing valve controlled by stops mounted on the movable end of the hydraulic cylinder.
  • the reversing valve is actuated by one of the stops, with the result that the assisted control brings the three-position slide valve to its left position by which the cylinder deploys and raises the weight.
  • the second stop actuates the reversing valve again and the power control brings the three-position slide valve to its right position, by which the weight falls and the cylinder retracts again.
  • This automatic and repetitive cycle can be interrupted by disconnecting the power control, whereby the three-position slide valve is brought to its central neutral position by means of springs mounted in the valve.
  • the cylinder and the pump are connected without pressure to the tank.
  • there is a pressure in the cylinder equal to that created by the weight of the hammer, multiplied by the reduction factor of the pulley system divided by the effective surface of the cylinder.
  • this pressure must however be significantly higher in order to be able to accelerate the weight in a very short time interval, up to a speed at which the entire flow of the pump is consumed by the jack.
  • this pressure is equal to the opening set pressure of the pressure relief valve . The product of this opening pressure multiplied by the pump flow rate determines the required power of the motor.
  • the motor and the pump are loaded and discharged in spurts, which is unfavorable for the life of these parts.
  • the power of the motor and the size of the pump must be much greater than what is theoretically necessary depending on the power per entire cycle. This is explained by the fact that the power of the engine is determined by the first part of the cycle.
  • the ARROW machine In order to be able to treat a large area in a short time during a concrete surface demolition operation, the ARROW machine is provided with very slow speed traction. This ensures that the machine progresses at a constant speed, so that the blows are distributed evenly over the surface to be broken. In order not to hinder progress, the hammer must be lifted immediately after the blow. This is achieved by adjusting the position of the stop along the cylinder rod so that the three-position slide valve is switched before the hammer hits the ground. This has the consequence that the flow which flows from the jack at the end of the fall is not brought any longer without pressure with the flow from the pump to the tank but rather drilled with great force through the pressure relief valve. This pressure relief valve must therefore be very large and able to open very quickly in order to be able to process this large flow without pressure surges. In addition, this energy is also lost and turns into heat.
  • Another problem of the ARROW machine lies in the fact that if, following an uneven surface, the hammer hammer drifts to the side, the enormous forces which appear on the guide are not taken up sufficiently, which can cause a break in the right of the fixing of the guide.
  • the present invention provides a machine of the type described in the first paragraph, characterized in that the pressure circuit comprises a hydraulic accumulator under pressure preload, which is connected to the side of the hydraulic pump and which is connected to the hydraulic cylinders by means of non-return valves.
  • a hydraulic accumulator consists of a pressure-resistant tank, in which a pocket is filled with nitrogen under pressure so that a certain quantity of hydraulic oil within certain pressure limits is accumulated and released under pressure.
  • a hydraulic accumulator is connected both on the discharge side of the pump and on the reflux side towards the tank, which accumulators being connected by non-return valves with each of the jacks.
  • the non-return valves are of the "controlled non-return valve” type so that they can take over the switching functions of a three-position slide valve.
  • these are non-return valves of the "cartridge” type which makes it possible to assemble these in a single distribution block which makes it possible to limit the number of conduits.
  • the guides of the hammer hammers are suspended elastically from the chassis by means of rubber sleeves.
  • the invention also relates to a method for operating the machine described above, said method being characterized in that the surplus oil consumed by a jack is supplemented during the stroke upward of the hammer, with oil from the hydraulic accumulator maintained at constant pressure, so that the hammer is subjected to constant acceleration.
  • the hydraulic pump is controlled by a pressure regulator, which is set to a pressure slightly higher than the operating pressure, so that the pump immediately turns to no load when the machine is stopped and it is immediately charged when the machine is restarted.
  • the automatic succession of impacts obtained by an electrical control system by means of wear-resistant induction switches without contact, so that the assembly can be controlled remotely.
  • the hydraulic power control circuit is replaced by an electrical circuit in which a switching valve controlled by stops is replaced by a number of induction or magnet switches reacting to the presence of metal in the immediate vicinity of their measuring head.
  • the machine according to the invention consists of a series of four pounder hammers 2, 3, 4, 5 arranged vertically next to each other on a movable frame 6.
  • the pounder hammers 2, 3, 4, 5 are each actuated by a single hydraulic cylinder 7, 8, 9, 10 provided with a pulley system (see FIG. 1).
  • the concrete is broken by the hammer hammers 2, 3, 4, 5 which move up and down along tubular guides 20, 21, 22, 23.
  • the hammer hammers are pulled using a cable 24 and pulleys 25, 26 fixed to each of the two ends of the cylinders 7, 8, 9, 10.
  • the force required to lift the hammer hammers 2, 3, 4, 5 is exerted by the pulley system thanks to the extension of the hydraulic cylinders 7, 8, 9, 10 which are connected to the high pressure accumulator 14.
  • the hydraulic cylinder 7, 8, 9, 10 is connected to the low-pressure accumulator 30. Since the force on the cable 24 almost fades, the hammer 2, 3, 4, 5 sketches a movement which ends with an impact on the surface to be broken 28.
  • the tubular guides 20, 21, 22, 23 are each fixed separately to the frame 6 by means of a hinge 48 so that each of them can be brought in using a double action hydraulic cylinder 41 in horizontal transport position. In this horizontal position, the tubular guides 20, 21, 22, 23 are supported on the specially designed diesel tank 42.
  • a hydraulic pump 12 which draws oil from a reservoir 27 and feeds a hydraulic circuit 13, formed of a high pressure accumulator 14 provided with a nitrogen bag inflated to a pressure of preload of 120 bars (12 Mega Pa), a pressure relief valve 16 set at 180 bars (18 Mega Pa), a hydraulic cylinder which, from 115 bars (11.5 Mega Pa), can maintain balance and lift the hammer, a controlled check valve 18 which still allows the oil to flow freely out of the cylinder but does not allow the oil to be brought to the cylinder until it is not activated, a controlled non-return valve 19 which allows the oil to always flow freely towards the jack, but does not allow the oil to to flow out of the jack only when activated and from a switching valve 15 in which the oil can flow freely when it is at rest, but which is closed in the activated position.
  • a non-return valve 35 with spring which never lets oil leave the tank and allows the admission of oil into the tank only from a pressure of 10 bars (1 Mega Pa) in the low pressure accumulator 30 provided with a nitrogen bag inflated to a constraint pressure of 6 bars (0.6 Mega Pa).
  • the pump begins to deliver an oil flow.
  • This flow begins to seek the easiest outcome. If the cable of the pulley system mounted on the jack 7 is loose, the flow causes the jack to deploy by the valve 15 and the valve 19 until the cable is stretched. Then the nitrogen pocket of the low pressure accumulator 30 is compressed. When the bag is pushed in, the pressure in the bag increases and, consequently, the oil pressure gradually increases from the initial pressure from 6 bars to 10 bars. At a pressure of 10 bars, the spring-loaded check valve 35 opens and the flow again flows to the tank. However, if the switching valve 15 is closed, the flow of the pump has no outlet to the tank or to the low pressure accumulator.
  • the controlled non-return valve 18 does not temporarily allow passage to the cylinder, the nitrogen pocket of the high pressure accumulator 14 is compressed.
  • the pressure gradually increases from the prestressing pressure of the pocket, namely 120 bars (12 Mega Pa) to a pressure of 170 bars (17 Mega Pa).
  • the pressure regulator 29 interrupts an electrical contact, whereby the switching valve 15 opens again and the oil pressure flows under a pressure of only 10 bars (1 Mega Pa) through a valve 35 to the tank.
  • the accumulator 14 is kept inflated under a pressure of 170 bars (17 Mega Pa) because the non-return valve 31 prevents backflow of oil.
  • a pressure relief valve 16 is provided for safety, which allows the oil to flow back under a pressure of 180 bars (18 Mega Pa) to the reservoir.
  • the weight can now be lifted by opening the controlled non-return valve 18. Oil under a pressure of 170 bars (17 Mega Pa) can flow from the accumulator 14 to the jack 7. This is sufficient to deploy the jack 7 and communicate an upward movement to the hammer.
  • the nitrogen pocket in the accumulator 14 expands meanwhile thanks to which the pressure in the pocket and therefore the oil pressure decreases from 170 bars (17 Mega Pa) to 165 bars (16.5 Mega Pa) at as the oil flows from the accumulator 14 to the jack 7.
  • the pressure regulator 29 again interrupts the electrical contact and the valve switching 15 is closed.
  • the flow rate of the pump which until now has flowed under a pressure of only 10 bar (1 Mega Pa) towards the tank, is now also brought to the jack 7.
  • the upward speed of the hammer and therefore the flow rate consumed by the jack is greater than the flow rate delivered by the pump 12.
  • the balance of the flow rate consumed by the jack is completed during the upward movement with oil from the accumulator 14.
  • the nitrogen pocket in the accumulator 14 continues to expand and the pressure continues to decrease gradually.
  • the cylinder 7 retracts again.
  • the flow coming from the jack 7 during the downward movement is first collected by the low pressure accumulator 30 until a pressure of 10 bar (1 Mega Pa) reigns.
  • the non-return valve 35 then opens and the escaping flow is again brought to the tank.
  • the valve 19 is closed and valve 18 opened again.
  • the flow flowing out of the jack 7 is no longer diverted to the tank but must be collected in the high pressure accumulator 14 at the same time as the flow of the pump.
  • the flow rate of the pump is collected by the accumulator 14 throughout the period in which the valve 18 was closed. A few moments later, when the impact hammer hits the ground, the impact hammer will immediately start to rise again since the jack is pressed again, already preventively, by high pressure. Due to the inertia, the upward speed of the hammer hammer is not immediately high enough to allow the cylinder to consume the entire flow of the pump.
  • the excess pump flow is now also collected by the high pressure accumulator 14. As the hammer is subjected to an acceleration, the flow consumed by the jack 7 far exceeds the flow of the pump. The deficit in flow consumed is filled by the reuse of an excess flow collected in the accumulator 14.
  • Hydraulic efficiency is optimal in all circumstances. If the non-return valve 35 armed with a spring and the low pressure accumulator 30 were deleted, the theoretical yield should be 100%. All the energy will be fully transferred to the roadway. Even the kinetic energy of the impact of the collision is reused.
  • the upward speed is limited by the pump flow and if this maximum speed is reached, the pressure decreases again from the value at which the pressure relief valve is set (for example 180 bar) to a value for which the balance reigns with the mass of the hammer (for example around 115 bars) and the engine power is only partially used.
  • the hammer hammer is subjected to an acceleration during the entire ascending cycle. Despite the much lower pump flow, the hammer works faster for the same given maximum pressure.
  • the pump power is used continuously and uniformly.
  • Another advantage of the invention is the fact that the hydraulic system can be easily extended to several pounder hammers 2, 3, 4, 5. As described above, the use of several pounder hammers according to conventional systems is made difficult due to timing issues and the installed power of motors and pumps.
  • FIG. 6 illustrates an embodiment comprising four pounder hammers according to the invention.
  • a diesel engine 11 drives a hydraulic pump 12, for example of the BOSCM RPK 63 type with electronically adjustable variable flow rate
  • the pressure circuit 13 comprises a pressure accumulator 14 with a capacity of 20 liters, for example of the BOSCM HY / AB20 / type 330C using a test pressure of 330 bars, a low pressure accumulator 30 with a capacity of 10 liters, for example of the OLEAR IBV 10-16 type.
  • valves 18, 19 are assembled in a control block 17 and four jacks 7, 8, 9, 10 are connected to this control block.
  • pressure compensated butterfly valves 33, 34 are installed, which have no influence in normal operation, but which, when the pulley system cable breaks, limit the leakage of accumulators in order to avoid that in the event of a cable break, the unsolicited cylinder does not slide too quickly and does not deteriorate.
  • a second pressure regulator 32 is provided, set to a slightly lower value which gives the operator a warning signal so that he can decrease the flow in time.
  • a filter 36 is mounted on the reflux pipe to the reservoir 27. Another advantage of the low pressure accumulator 30 is the fact that the filter 36 can be kept relatively small.
  • the low pressure accumulator 30 At least, when a flow is discharged from the cylinder to the reflux conduit, part of it is collected by the low pressure accumulator 30 due to the increase in pressure which takes place in the reflux conduit 59 by the resistance of the filter. This flow which has been collected will be returned again and will flow through the filter 36 towards the reservoir 27 at the times when no flow or only a low flow flows out of the jack towards the reflux duct.
  • the low pressure accumulator 30 also serves as a buffer to facilitate passage through the filter 36 to the reservoir 27.
  • the four sets of controlled non-return valves 18, 19 are assembled in a control block 17 as shown in FIG. 7.
  • the pressure relief valve 16 is mounted in the control block and that three valves additional controlled non-return valves 44, 45, 46 and two butterfly valves 40 are installed in the block. These additional valves are used to slowly lift and lower the hammer hammers, for example when mounting the machine or transforming it into the transport position.
  • a hammer 2, 3, 4, 5 can be lifted slowly by closing the valve 46 and opening one of the valves 18.
  • a low flow rate adjusted using the butterfly valve 40 will flow through the valve 44 and the butterfly valve 40 as well as the open valve 18 towards the chosen cylinder 7, 8, 9, 10.
  • the four hammer hammers 2, 3, 4, 5 can be dropped simultaneously and slowly by closing the valves 44 and 46 and opening the valve 45. A low flow will flow through the valves 18, through the second valve throttle valve 40 and the open valve 45 in the direction of reflux and of the reservoir 27.
  • the circuit and the operation are identical to the circuit and to the operation described for FIG. 5.
  • the pump 12 To actuate this single pestle hammer , the pump 12 must deliver, for example, a flow rate of 30 liters per minute. If we stop this hammer and if we start another hammer, for example the one that is actuated by the jack 8, exactly the same thing happens at the same pressures and flow rates given the fact that the hammers are completely identical.
  • pump 12 must deliver a flow of 60 liters per minute and the two pounder hammers must each carry out their succession of strokes at the same pressure and according to cycles identical. These cycles overlap each other in either way. This means that currents appear in the circuit and in particular the currents to and from the high pressure accumulator 14 can strengthen or neutralize, depending on the way in which the cycles overlap each other.
  • the accumulator always collects all the differences between a delivered or consumed flow rate and the functioning of one of the hammer hammers is not influenced by the functioning of the other hammer hammer. This remains valid even if three or four pounder hammers are started, in which case the pump 12 must deliver a flow of 90 l / min or the full flow of 120 l / min.
  • the pump always delivers a constant flow to the accumulator 14 at a substantially constant pressure if at least the accumulator is large enough.
  • the average cycle times of the four hammer hammers adapt together to the flow delivered by the pump. No form of synchronization between the various hammers is required.
  • the hammers must be made identically to work at equal speed or must have at least the same ratio of the mass of the hammer multiplied by the reduction factor of the pulley system and the active surface of the jack 7, 8, 9, 10 to be able to work at equal speed, at equal pressure. It is of course possible to lift the hammer hammers at different heights, in which case the one set at the lowest fall height will work the fastest.
  • the pump flow can be optimally adjusted with the pressure regulator as an auxiliary means.
  • the right part of the pressurized circuit 13 of FIG. 6 is intended to straighten and lower the guide tubes 29. It is actuated manually.
  • the control drawers consist of a single element 38 and a group 39 of four elements assembled together by which each of the jacks 41 can be actuated separately. This set forms a safety command because the operator must stay in a sheltered place to be able to control with both hands at the same time the single element 38 and one of the other elements 39.
  • the off-center valves (or dual brake valves) 37 are necessary because the center of gravity moves beyond the pivot point. With all the drawers in the rest position, the jacks 41 are protected against overpressure.
  • a limit switch for example inductive proximity switches which react to the presence of metal in the immediate vicinity of their measuring head.
  • the magnetic switches 46 are mounted on a plastic slat, which is fixed to the cylinder so that a metal guide rod 44 of the cylinder 7, 8, 9, 10 is measured parallel to their ends 47 from top to bottom.
  • the electrical diagram of the control system part of which is illustrated in FIG. 8, allows the selection of three heights of fall of the hammer-pestle, this using a switch 43 with three positions. With the switch 43 occupying the position shown in Figure 8, only the lower magnetic switch 46 and the middle switch of the three upper work.
  • the lower switch 46 is mounted in such a way that the jacks 7, 8, 9, 10 are pressurized before the hammer strikes the ground to be broken.
  • the cylinders 7, 8, 9, 10 can again contract even further to avoid breaking the cable in the event that the hammer hammer should fall into a hole.
  • a rupture which often occurs in a known machine is the tearing of the fastening of the guides. This is due to the fact that the hammer hammer is thrown laterally during a fall on uneven ground. Due to the rigidity of the guide attachment, this causes significant stresses which over time cause tears in the attachment, which is nevertheless made solidly.
  • tubular hammer guides are pivotally mounted on the frame 6 using a pivoting construction 48 (Fig. 9) which includes internal rubber bushings.
  • the shocks are absorbed elastically and effortlessly, from the front, by a solid rubber stopper 49 fixed on the guides 20, 21, 22, 23, at the rear by the butterfly valves 37 which ensure a very slight play of the jacks 41 towards the rear and the side thanks to the suspension system comprising a hinge 48 according to FIG. 9.
  • the guide 20, 21, 22, 23 is fixed to a thick-walled tube 51 which comprises two sockets 58 made of rubber.
  • the assembly is carried by an axis 50 which rests on two legs 52 to be fixed to the chassis 6.
  • the tabs 52 are held in place by clamps 53 and nuts 54, on the one hand, and annular stops 55, on the other hand. They include plain bearings 56, 57 in two parts so that the guide tube 20 can be articulated like a hinge.
  • the smooth stops 56, 57 are made in the form of a sphere in FIG. 9, which simplifies and corrects the alignment errors. Other forms of bearing are possible.
  • the lateral shocks are absorbed elastically by the rubber sockets 58.
  • the sockets 58 can be made of solid rubber elements in one piece as illustrated in FIG. 9 or can consist of metal tubes with thin internal and external walls between which a layer of rubber has been vulcanized.
  • the machine can be mounted on a chassis in the form of a monoaxial trailer which can be pulled, for example, by an agricultural tractor or another vehicle at reduced speed.
  • a console fitted with ten electrical control levers By placing in the cabin driving the towing vehicle a console fitted with ten electrical control levers, the various operations necessary for operation can be carried out from the cab. Thanks to the fact that no drive element has to be built and given the general concept of the project, the chassis and mechanical parts are quick and inexpensive to build. It is therefore not justified to increase the costs of production and operation of the machine to break a concrete surface by installing an independent drive and a clean control cabin.
  • the number of hydraulic circuits is greatly simplified the distribution block 17 with cartridge valves which encompasses a whole series of functions with only six connections.
  • Each cartridge valve element can be disassembled separately and is easily accessible. They also offer optimum sealing, extremely short switching times and require, for the same size, only a low electrical control power.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Working Measures On Existing Buildindgs (AREA)
  • Crushing And Grinding (AREA)
  • Shovels (AREA)
  • Percussive Tools And Related Accessories (AREA)
EP91870005A 1990-01-16 1991-01-15 Maschine zum Zerstören von Betonoberflächen Withdrawn EP0442860A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BE9000056 1990-01-16
BE9000056A BE1003135A3 (nl) 1990-01-16 1990-01-16 Machine voor het verbrijzelen van betonoppervlakken.

Publications (1)

Publication Number Publication Date
EP0442860A1 true EP0442860A1 (de) 1991-08-21

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EP91870005A Withdrawn EP0442860A1 (de) 1990-01-16 1991-01-15 Maschine zum Zerstören von Betonoberflächen

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EP (1) EP0442860A1 (de)
BE (1) BE1003135A3 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008007484A1 (en) * 2006-07-10 2008-01-17 Caterpillar Japan Ltd. Hydraulic control system for working machine
CN102286911A (zh) * 2011-05-04 2011-12-21 河南路太养路机械股份有限公司 多工位快速卸料装料机构
CN108266412A (zh) * 2018-01-16 2018-07-10 何学才 一种已生产的步进加热炉液压平衡节能改造装置
CN108342971A (zh) * 2018-04-28 2018-07-31 招商局重庆交通科研设计院有限公司 一种移动式水泥路面破碎机

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3911679A (en) * 1974-12-26 1975-10-14 Allis Chalmers Closed center hydraulic system with pump and accumulator output for high speed lift
US4315550A (en) * 1975-10-23 1982-02-16 Fulkerson David W Self-propelled apparatus for setting cemetery markers and the like
DE8514700U1 (de) * 1985-05-15 1985-09-19 Peiner Maschinen- Und Schraubenwerke Ag, 3150 Peine Arbeitsgerät zum Zerbrechen von Felsgestein
US4852661A (en) * 1987-05-26 1989-08-01 Ellington David A Portable concrete hammer

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3911679A (en) * 1974-12-26 1975-10-14 Allis Chalmers Closed center hydraulic system with pump and accumulator output for high speed lift
US4315550A (en) * 1975-10-23 1982-02-16 Fulkerson David W Self-propelled apparatus for setting cemetery markers and the like
DE8514700U1 (de) * 1985-05-15 1985-09-19 Peiner Maschinen- Und Schraubenwerke Ag, 3150 Peine Arbeitsgerät zum Zerbrechen von Felsgestein
US4852661A (en) * 1987-05-26 1989-08-01 Ellington David A Portable concrete hammer

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008007484A1 (en) * 2006-07-10 2008-01-17 Caterpillar Japan Ltd. Hydraulic control system for working machine
CN102286911A (zh) * 2011-05-04 2011-12-21 河南路太养路机械股份有限公司 多工位快速卸料装料机构
CN108266412A (zh) * 2018-01-16 2018-07-10 何学才 一种已生产的步进加热炉液压平衡节能改造装置
CN108342971A (zh) * 2018-04-28 2018-07-31 招商局重庆交通科研设计院有限公司 一种移动式水泥路面破碎机
CN108342971B (zh) * 2018-04-28 2023-05-09 招商局重庆交通科研设计院有限公司 一种移动式水泥路面破碎机

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Publication number Publication date
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