CN104912863B - Single-valve-core two-position three-way electro-hydraulic change valve applied to hydraulic pile hammer - Google Patents
Single-valve-core two-position three-way electro-hydraulic change valve applied to hydraulic pile hammer Download PDFInfo
- Publication number
- CN104912863B CN104912863B CN201510294914.8A CN201510294914A CN104912863B CN 104912863 B CN104912863 B CN 104912863B CN 201510294914 A CN201510294914 A CN 201510294914A CN 104912863 B CN104912863 B CN 104912863B
- Authority
- CN
- China
- Prior art keywords
- valve
- hydraulic
- piston
- oil
- valve core
- 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.)
- Active
Links
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
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D7/00—Methods or apparatus for placing sheet pile bulkheads, piles, mouldpipes, or other moulds
- E02D7/02—Placing by driving
- E02D7/06—Power-driven drivers
- E02D7/10—Power-driven drivers with pressure-actuated hammer, i.e. the pressure fluid acting directly on the hammer structure
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Magnetically Actuated Valves (AREA)
Abstract
The invention relates to a single-valve-core two-position three-way electro-hydraulic change valve applied to a hydraulic pile hammer. The technical solution is as follows: a valve oil distribution cover plate, a valve core body and a valve seat body actually form a hydraulic cylinder, the upper part of the valve core body forms a piston part of the hydraulic cylinder, the lower part of the valve core body forms a piston part of the hydraulic cylinder, the valve oil distribution cover plate (2) forms a cylinder part and back end cover of the hydraulic cylinder, and the upper part of the valve seat body forms a front end cover of the hydraulic cylinder; the lower part of a valve core (6) is matched with the lower part of the valve seat body so as to realize an on-off function of a two-position three-way valve. The invention has the beneficial effects that due to the design of a conical sealing surface, when the working state is linear seal, the leakage amount is reduced, and the volumetric efficiency of a hydraulic system is improved; due to the design of seal length of a slide valve, the communication of interlocked valve ways in the working state is avoided, so that the working of the system is more reliable, the energy loss is avoided, and meanwhile, such advantages that the interlocking among slide valve ways and the seal of a conical valve are excellent, and the leakage is low are provided.
Description
Technical field
It is more particularly to a kind of to be used for hydraulic pile hammer the present invention relates to the electro-hydraulic reversing valve and method of a kind of hydraulic pile hammer
Single spool two-position three way electro-hydraulic reversing valve.
Background technology
At present, the hydraulicdirectional control valve for being used in hydraulic pile hammer is divided into guiding valve and 2/2-way cone valve by spool type,
Wherein guiding valve is clearance seal, and sealing is poor.There is certain seal length in valve element, therefore sliding valve movement has one with valve port
Individual dead band, is not in instantaneous conducting phenomenon between valve road.Poppet spool valve semi-cone angle is generally 12 °~20 °, is line when valve port is closed
Sealing, good seal performance and is active in one's movements, however it is necessary that multiple valves are applied in combination, reaches the purpose of multi-way reversing, is commutating
Easily occurs instantaneous conducting phenomenon between valve road in journey.
The content of the invention
A kind of drawbacks described above that the purpose of the present invention exists aiming at prior art, there is provided list for hydraulic pile hammer
Valve element two-position three way electro-hydraulic reversing valve, reduces the seal length of guiding valve, retains a motion dead band, is not in instantaneous between valve road
To logical phenomenon；Cone valve provides the sealing under working condition so that favorable sealing property.
Its technical scheme is to include solenoid directional control valve（1）, valve oil distributing cover plate（2）, valve core piston（3）, upper fixing nut
（4）, upper valve base（5）, valve element（6）, valve seat set（7）, lower valve base（8）, lower fixing nut（9）And corresponding seal,
Described valve oil distributing cover plate（2）Top is machined with and solenoid directional control valve（1）The oilhole and solenoid directional control valve of cooperation are consolidated
Determine hole, valve oil distributing cover plate（2）Inside be with three cylinders of step, for respectively with valve core piston（3）On two work
Plug face coordinate and with valve seat set（7）Coordinate；
Described valve element（6）It is hollow cylinder, valve core piston（3）Be with two hollow cylinders of step, it is described
Valve element（6）And valve core piston（3）Valve core is constituted after being connected through a screw thread；
The valve seat set（7）It is hollow cylinder, inner cylinder and valve element（6）Coordinate, exterior circular column is respectively with valve with oil
Cover plate（2）, with cargo tank（10）On valve mounting hole coordinate,
Described valve seat set（7）, upper valve base（5）, lower valve base（8）, upper fixing nut（4）, lower fixing nut（9）It is coaxial
Line is installed and constitutes valve body, and valve core bottom is installed in valve body, and valve core top is installed on valve oil distributing cover plate（2）It is interior；Institute
State valve oil distributing cover plate（2）, valve core, valve body effectively form a hydraulic cylinder, the work of hydraulic cylinder is constituted above valve core
Plug portion, constitutes the piston portion of hydraulic cylinder, valve oil distributing cover plate below valve core（2）The cylinder part of composition hydraulic cylinder is with after
Portion's end cap, valve body top constitutes the drive end bearing bracket of hydraulic cylinder；Valve element（6）Below part with valve body below partly coordinate,
Realize the switching function of two position three-way valve.
Above-mentioned valve element（6）On be machined with center spool hole（62）With valve element oil inlet passage hole（63）, valve element drainback passage oil
Hole（61）, wherein, center spool hole（62）Top connection valve element drainback passage oilhole（61）, bottom connection valve element oil inlet passage
Hole（63）；Valve element oil inlet passage hole（63）For connecting hydraulic oil oil-feed；Valve element drainback passage oilhole（61）For connecting hydraulic pressure
Oily oil return；Valve element（6）Intermediate step face of cylinder two ends are machined with conical seal (contact) face respectively, for upper valve base, lower valve base it is close
Front cover cooperatively forms linear sealing.
Above-mentioned valve core piston（3）Two steps on be machined with seal groove for installing seal, form two work
Plug face；The relatively large step circles cylinder of diameter is valve core piston working piston（42）, its effect is the up and down motion for promoting valve element；
The relatively small step of diameter is valve core piston dummy piston（41）, its effect is the hydraulic action of balance valve core top and bottom
Power, reduces valve core movement resistance.
Above-mentioned valve seat set（7）It is provided with valve seat set oil-feed access opening（72）, valve seat set oil return access opening（71）, and valve seat packs into
Oily access opening（72）, valve seat set oil return access opening（71）With valve element oil inlet passage hole（63）, valve element drainback passage oilhole（61）Even
It is logical.
Above-mentioned upper valve base（5）, lower valve base（8）Set shape structure is, in one end inner surface processing conical seal (contact) face of set, is used
In cooperatively forming linear sealing with the conical seal (contact) face on valve element；Upper valve base（5）, lower valve base（8）It is separately mounted to valve seat set（7）'s
Top and bottom, use fixing nut（4）, lower fixing nut（9）It is fixed on valve seat set（7）It is interior.
A kind of application method of single spool two-position three way electro-hydraulic reversing valve for hydraulic pile hammer that the present invention is mentioned, bag
Include following steps：
Valve oil distributing cover plate（2）, valve core, valve body constitute a hydraulic cylinder, above valve core constitute hydraulic cylinder work
Plug portion, constitutes the piston portion of hydraulic cylinder, valve oil distributing cover plate below valve core（2）The cylinder part of composition hydraulic cylinder is with after
Portion's end cap, valve body top constitutes the drive end bearing bracket of hydraulic cylinder；Valve element（6）Below part with valve body below partly coordinate,
Realize the switching function of two position three-way valve；
When being moved on solenoid valve control valve core piston, hydraulic oil oil inlet passage is connected with centre bore, double media operation hydraulic pressure
Cylinder oil-feed, when solenoid valve control valve core piston is moved down, hydraulic oil drainback passage is connected with centre bore, double media operation hydraulic cylinders
Oil return.
The beneficial effects of the invention are as follows：Due to the design of conical seal (contact) face, linear sealing is sealed into working order, reduce
Leakage rate, improves hydraulic system volumetric efficiency；The dead band changed between because the design of guiding valve seal length has working condition,
Conducting during avoiding working condition between interlock valve road, makes system work more reliable, it is to avoid energy loss；So that of the invention
Have the advantages that the excellent leakage of the sealing of interlocking and cone valve between guiding valve path is small simultaneously.
Brief description of the drawings
Fig. 1 is structure chart of the invention；
Fig. 2 is valve cover structure chart of the invention；
Fig. 3 is the A-A structure charts of valve cover of the invention；
Fig. 4 is valve core structure figure of the invention；
Fig. 5 is valve core piston structure chart of the invention；
Fig. 6 is valve seat noose composition of the invention；
In upper figure：Solenoid directional control valve 1, valve oil distributing cover plate 2, valve core piston 3, upper fixing nut 4, upper valve base 5, valve element 6, valve
Cover for seat 7, lower valve base 8, lower fixing nut 9, with cargo tank 10, valve core piston dummy piston 41, valve core piston working piston 42, valve element
Drainback passage hole 61, center spool hole 62, sealing cone 65 under sealing cone 64, valve element on valve element oil inlet passage hole 63, valve element,
Valve seat set oil return access opening 71, valve seat set oil-feed access opening 72.
Specific embodiment
As shown in figure 1, the single spool two-position three way electro-hydraulic reversing valve for hydraulic pile hammer that the present invention is mentioned, including electricity
Magnetic reversal valve 1, valve oil distributing cover plate 2, valve core piston 3, upper fixing nut 4, upper valve base 5, valve element 6, valve seat set 7, lower valve base 8, under
Fixing nut 9, with cargo tank 10, wherein be provided with valve element valve element drainback passage hole 61, center spool hole 62, valve element oil-feed lead to
Road hole 63, is arranged in respect of valve seat set oil return access opening 71, valve seat set oil-feed access opening 72 in valve seat.
As shown in figure 1, magnetic valve 1 is arranged on the upper face of valve oil distributing cover plate 2 by bolt.
The top of valve oil distributing cover plate 2 is machined with the oilhole and solenoid directional control valve 1 coordinated with solenoid directional control valve 1 as Figure 2-3
Fixing hole, is, with three cylinders of step, to be respectively used to and two piston areas on valve core piston inside valve oil distributing cover plate 2
Coordinate and covered with valve seat and coordinate, valve oil distributing cover intralamellar part is machined with oilhole for the oil-feed of solenoid directional control valve 1 and oil return in addition, and will
The working solution force feed of the control of solenoid directional control valve 1, towards the epicoele and cavity of resorption of the working piston in valve core piston 3.
As shown in figure 4, valve element 6 is hollow cylinder, center oilhole 62 and oil inlet passage oilhole 63, oil return are machined with thereon
Passage oilhole 61.As shown in figure 1, wherein center oilhole connects 62 work oilholes；Oil inlet passage oilhole 63 is used to connect hydraulic oil
Oil-feed；Drainback passage oilhole 61 is used to connect hydraulic oil oil return.It is close that valve element intermediate step face of cylinder two ends are machined with taper respectively
Envelope, 64,65, cooperatively form linear sealing for the sealing surface with upper valve base 5, lower valve base 8.
As shown in figure 5, valve core piston is with two hollow cylinders of step, it is machined with step close for installing
The seal groove of sealing, forms two pistons 41,42.The relatively large step circles cylinder of diameter is working piston 42, and its effect is to push away
The up and down motion of movable valve plug；The relatively small step of diameter is dummy piston 41, and its effect is the liquid of balance valve core top and bottom
Pressure active force, reduces valve core movement resistance.
As shown in fig. 6, valve seat set 7 is hollow cylinder, inner cylinder and valve element coordinate, exterior circular column respectively with bonnet
Plate, with cargo tank valve mounting hole coordinate.Valve seat set 7 is also configured with oil inlet passage oilhole 72, drainback passage oilhole 71, these
Oil inlet passage oilhole 63, drainback passage oilhole 61 on oil inlet passage oilhole 72, drainback passage oilhole 71 and valve element 6 have determination
Position relationship.
Upper valve base, lower valve base are set shape structure, in one end inner surface processing conical seal (contact) face of set, for valve element
Conical seal (contact) face cooperatively form linear sealing.
As shown in figure 1, valve element 6 and valve core piston 4 constitute valve core, 8 points of upper valve base 5, lower valve base after being connected through a screw thread
Not An Zhuan valve seat set 7 top and bottom, with fixing nut 4, lower fixing nut 9 be fixed on valve seat cover 7 in.Valve seat set 7,
Upper valve base 5, lower valve base 8, upper fixing nut 4, the coaxial line of lower fixing nut 9 are installed and constitute valve body, and valve core bottom is installed on
In valve body, valve core top is installed in cover plate.
The application method of the single spool two-position three way electro-hydraulic reversing valve that the present invention is mentioned is：
As shown in figure 1, cover plate 2, valve core, valve body effectively form a hydraulic cylinder, liquid is constituted above valve core
The piston portion of cylinder pressure, constitutes the piston rod portion of hydraulic cylinder below valve element 6, cover plate constitutes the cylinder part of hydraulic cylinder with after
Portion's end cap.Valve seat covers the drive end bearing bracket that 7 tops constitute hydraulic cylinder.Partly coordinate below part and valve seat set 7 below valve element 6,
Realize the switching function of two position three-way valve.When being moved on solenoid valve control valve core piston 42, hydraulic oil oil inlet passage and centre bore
Connect, double media operation hydraulic cylinder oil-feeds, when solenoid valve control valve core piston 42 is moved down, hydraulic oil drainback passage and centre bore
Connect, double media operation hydraulic cylinder oil returns.
The advantage of the single spool two-position three way electro-hydraulic reversing valve that the present invention is mentioned is：
Meanwhile, have the advantages that the excellent leakage of the sealing of interlocking and cone valve between guiding valve path is small.
The above, is only presently preferred embodiments of the present invention, and the formal limitation of non-invention, every according to the present invention
Technical spirit simple modification, equivalent variations and modification are made to above example, belong to technical solution of the present invention scope it
It is interior.
Claims (3)
1. a kind of single spool two-position three way electro-hydraulic reversing valve for hydraulic pile hammer, it is characterized in that：Including solenoid directional control valve
（1）, valve oil distributing cover plate（2）, valve core piston（3）, upper fixing nut（4）, upper valve base（5）, valve element（6）, valve seat set（7）, lower valve
Seat（8）, lower fixing nut（9）And corresponding seal, described valve oil distributing cover plate（2）Top is machined with and solenoid directional control valve
（1）The oilhole and solenoid directional control valve fixing hole of cooperation, valve oil distributing cover plate（2）Inside is, with three cylinders of step, to be used for
Respectively with valve core piston（3）On two piston areas coordinate and with valve seat set（7）Coordinate；Described valve element（6）It is open circles
Cylinder, valve core piston（3）It is with two hollow cylinders of step, the valve element（6）And valve core piston（3）Connected by screw thread
Valve core is constituted after connecing；The valve seat set（7）It is hollow cylinder, inner cylinder and valve element（6）Coordinate, exterior circular column respectively with
Valve oil distributing cover plate（2）, with cargo tank（10）On valve mounting hole coordinate；Described valve seat set（7）, upper valve base（5）, lower valve base（8）、
Upper fixing nut（4）, lower fixing nut（9）Coaxial line install and constitute valve body, valve core bottom is installed in valve body, valve
Core body top is installed on valve oil distributing cover plate（2）It is interior；The valve oil distributing cover plate（2）, valve core, valve body effectively form a liquid
Cylinder pressure, constitutes the piston portion of hydraulic cylinder above valve core, the piston rod portion of hydraulic cylinder is constituted below valve core, and valve is matched somebody with somebody
Oil cap plate（2）The cylinder part and rear portion end cap of hydraulic cylinder are constituted, valve body top constitutes the drive end bearing bracket of hydraulic cylinder；Valve element（6）
Below part with valve body below partly coordinate, realize the switching function of two position three-way valve.
2. the single spool two-position three way electro-hydraulic reversing valve for hydraulic pile hammer according to claim 1, it is characterized in that：Institute
State valve element（6）On be machined with center spool hole（62）With valve element oil inlet passage hole（63）, valve element drainback passage oilhole（61）, its
In, center spool hole（62）Top connection valve element drainback passage oilhole（61）, bottom connection valve element oil inlet passage hole（63）；Valve
Core oil inlet passage hole（63）For connecting hydraulic oil oil-feed；Valve element drainback passage oilhole（61）For connecting hydraulic oil oil return；Valve
Core（6）Intermediate step face of cylinder two ends are machined with conical seal (contact) face respectively, and shape is coordinated for the sealing surface with upper valve base, lower valve base
Into linear sealing.
3. the single spool two-position three way electro-hydraulic reversing valve for hydraulic pile hammer according to claim 1, it is characterized in that：Institute
State valve core piston（3）Two steps on be machined with seal groove for installing seal, form two piston areas；Diameter phase
It is valve core piston working piston to big step circles cylinder（42）, its effect is the up and down motion for promoting valve element；Diameter is relatively small
Step be valve core piston dummy piston（41）, its effect is the hydraulic action of balance valve core top and bottom, reduces valve element
The resistance of motion.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710335705.2A CN107013523B (en) | 2015-06-02 | 2015-06-02 | The reversing arrangement and application method of a kind of hydraulic hammer |
| CN201510294914.8A CN104912863B (en) | 2015-06-02 | 2015-06-02 | Single-valve-core two-position three-way electro-hydraulic change valve applied to hydraulic pile hammer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510294914.8A CN104912863B (en) | 2015-06-02 | 2015-06-02 | Single-valve-core two-position three-way electro-hydraulic change valve applied to hydraulic pile hammer |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710335705.2A Division CN107013523B (en) | 2015-06-02 | 2015-06-02 | The reversing arrangement and application method of a kind of hydraulic hammer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104912863A CN104912863A (en) | 2015-09-16 |
| CN104912863B true CN104912863B (en) | 2017-05-24 |
Family
ID=54082221
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510294914.8A Active CN104912863B (en) | 2015-06-02 | 2015-06-02 | Single-valve-core two-position three-way electro-hydraulic change valve applied to hydraulic pile hammer |
| CN201710335705.2A Active CN107013523B (en) | 2015-06-02 | 2015-06-02 | The reversing arrangement and application method of a kind of hydraulic hammer |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710335705.2A Active CN107013523B (en) | 2015-06-02 | 2015-06-02 | The reversing arrangement and application method of a kind of hydraulic hammer |
Country Status (1)
| Country | Link |
|---|---|
| CN (2) | CN104912863B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109594561B (en) * | 2018-11-07 | 2020-10-27 | 太原理工大学 | Hydraulic Linear Impact Vibratory Pile Hammer |
| CN113958726B (en) * | 2021-10-19 | 2024-03-08 | 涌镇液压机械（上海）有限公司 | Valve core structure of internal flow reversing valve |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2949231C2 (en) * | 1979-12-07 | 1984-12-13 | Mannesmann Rexroth GmbH, 8770 Lohr | Pressure medium valve, in particular pressure reducing valve |
| DE4131830C3 (en) * | 1991-09-20 | 2000-03-23 | Mannesmann Ag | Tappet for slide valves |
| CN2340990Y (en) * | 1997-12-31 | 1999-09-29 | 张健华 | Piston controlling valve for various hydraulic pile hammer |
| US7210501B2 (en) * | 2004-09-29 | 2007-05-01 | Mac Valves, Inc. | Directly operated pneumatic valve having a differential assist return |
| CN201891689U (en) * | 2010-11-30 | 2011-07-06 | 天津工程机械研究院 | Cartridge inserted two-position three-way electro-hydraulic reversing valve |
| JP6015605B2 (en) * | 2013-09-17 | 2016-10-26 | 株式会社デンソー | Valve timing adjustment device |
| CN204783908U (en) * | 2015-06-02 | 2015-11-18 | 东营华晏石油技术有限公司 | A single valve core two -position three way electro -hydraulic reversing valve for hydraulic pile driving hammer |
-
2015
- 2015-06-02 CN CN201510294914.8A patent/CN104912863B/en active Active
- 2015-06-02 CN CN201710335705.2A patent/CN107013523B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN107013523B (en) | 2018-05-01 |
| CN104912863A (en) | 2015-09-16 |
| CN107013523A (en) | 2017-08-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103603840B (en) | Integrated hydraulic valve group and hydraulic driving system and concrete pump | |
| CN104912854B (en) | Single-valve hydro-pneumatic hydraulic pile hammer | |
| CN102889398B (en) | Shuttle valve, shuttle valve driving type device, winding drum brake cylinder control loop and crane | |
| CN104912863B (en) | Single-valve-core two-position three-way electro-hydraulic change valve applied to hydraulic pile hammer | |
| CN102434527B (en) | Hydraulic cylinder | |
| CN201096115Y (en) | Hydraulic combined valve | |
| CN207111584U (en) | Stroke-controllable automatic reciprocating hydraulic cylinder | |
| CN211852969U (en) | Cone valve type electromagnetic reversing valve | |
| CN201269232Y (en) | Combined multipath reversing solenoid valve | |
| CN204783908U (en) | A single valve core two -position three way electro -hydraulic reversing valve for hydraulic pile driving hammer | |
| CN201513403U (en) | Multistage cylinder integrated control hydraulic valve group | |
| CN203584934U (en) | Double-cavity pressurized oil cylinder device | |
| CN201916269U (en) | Integral manual multi-way change valve | |
| CN202834197U (en) | Two position bottom bracket reversing valve | |
| CN208123146U (en) | Solenoid valve commutation electric pump mechanism for the hydraulic overturning system of truck cap | |
| CN202851525U (en) | Rapid hydro-cylinder hydraulic system | |
| CN202203099U (en) | Electric hydraulic control high pressure large flux double-pump afflux and double-selection diverter valve | |
| CN203161701U (en) | Damped speed controllable hydraulic valve bank | |
| CN202646701U (en) | Double-motion stamping hydraulic cylinder seal structure | |
| CN214945373U (en) | Single-fluid bidirectional composite three-position four-way reversing valve | |
| CN211975569U (en) | Prefill valve for hydraulic system | |
| CN102748341A (en) | Quick cylinder hydraulic system | |
| CN204284037U (en) | A kind of hydraulic system, pumping system and concrete pumping equipment | |
| CN202194880U (en) | Hand-operated three-position four-position direction valve | |
| CN204739018U (en) | Single valve gas -liquid formula hydraulic pile driving hammer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |