Impact-resistant hydraulic system of breaking hammer type heading machine

Abstract

The invention belongs to the technical field of heading machines, and particularly relates to an anti-impact hydraulic system of a breaking hammer type heading machine. The device comprises a hydraulic oil pump, a breaking hammer, a breaking hammer propulsion oil cylinder and a boom oil cylinder multi-way valve group, a propulsion pressure control valve is connected between an S port of the hydraulic oil pump and an LS port of the boom oil cylinder multi-way valve group through a pipeline; a propelling one-way valve is connected between an outlet of the hydraulic oil pump and a port P of the boom oil cylinder multi-way valve set through a pipeline. The boom oil cylinder multi-way valve set comprises a plurality of control units, the breaking hammer thrust oil cylinder is connected to one control unit of the boom oil cylinder multi-way valve set, and an oil inlet pipeline of the breaking hammer thrust oil cylinder is connected with a thrust oil cylinder reverse thrust pressure control valve. Different propelling pressure values and reverse thrust pressure values can be set according to different rock hardness, the minimum propelling pressure and the minimum reverse thrust pressure are set while the rock breaking effect is met, reverse thrust vibration of an arm support and a whole machine is reduced, and the service life is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel boring machines, and in particular relates to an anti-shock hydraulic system for a breaker-hammer type tunnel boring machine. Background Art

[0002] When the tunnel boring machine is performing a breaker hammer crushing operation, it will generate a reverse thrust force on the boom and the entire machine, causing the boom and the crawler walking mechanism of the entire machine to be subjected to high-frequency impact force, resulting in defects such as fatigue fracture in the boom structure and the walking parts of the entire machine.

[0003] During the excavation operation, the breaker hammer's thrust cylinder maintains the thrust action so that the breaker hammer is pressed against the rock surface for crushing operations. At this time, a reverse impact force will be generated in the process of the breaker hammer crushing the rock. The extension force of the thrust cylinder is controlled by the extension pressure valve, and the breaker hammer's reverse thrust impact force is also controlled by the extension cylinder extension pressure valve. When this pressure is exceeded, the cylinder will passively retract. If the pressure is set too high, the breaker hammer will be pressed too tightly, which will affect the crushing effect. If the pressure is set too low, the breaker hammer's reverse thrust pressure will be too small, which will also affect the crushing effect.

[0004] In addition, when the breaker hammer is operating, it will generate a recoil force on the boom and the boom cylinder; the recoil force will generate an oil pressure shock in the cylinder, and the oil pressure shock will be transmitted to the boom structure and the walking tracks of the whole machine, causing fatigue and causing the boom and tracks to break.

[0005] If the breaker hammer / high-frequency hammer is not turned off in time when it does not touch the rock, the breaker / high-frequency vibration will be directly transmitted to the boom and the whole machine, causing vibration and affecting the life of the whole machine. Summary of the invention

[0006] In order to solve the above-mentioned problems existing in the prior art, the purpose of the present invention is to provide an anti-impact hydraulic system for a breaker-type tunnel boring machine, which can set different thrust pressure and reverse thrust pressure values ​​according to different rock hardnesses, thereby meeting the rock breaking effect and setting the minimum thrust and reverse thrust pressures, thereby reducing the reverse thrust vibration of the boom and the entire machine and improving the service life.

[0007] The technical solution adopted by the present invention is:

[0008] An anti-shock hydraulic system for a breaker-type tunnel boring machine includes an oil tank, a hydraulic oil pump, a boom cylinder multi-way valve group, a breaker hammer control valve group, a breaker hammer, a breaker hammer propulsion cylinder, a plurality of boom cylinders and two crawler travel cylinders, the hydraulic oil pump is connected to the oil tank through a pipeline, and the breaker hammer is connected to the breaker hammer control valve group through a pipeline;

[0009] It also includes a shuttle valve, which is connected to the S port of the hydraulic oil pump, the LS port of the boom cylinder multi-way valve group, and the LS port of the breaker hammer control valve group through pipelines, and a propulsion pressure control valve is connected to the pipeline between the shuttle valve and the hydraulic oil pump;

[0010] The outlet of the hydraulic oil pump is connected to a propulsion check valve through a pipeline, and the outlet pipeline of the propulsion check valve is divided into two ways, which are respectively connected to the P port of the boom cylinder multi-way valve group and the P port of the breaker hammer control valve group;

[0011] The boom cylinder multi-way valve group includes several control units, the breaker hammer thrust cylinder, several boom cylinders and two crawler travel cylinders are respectively connected to the several control units of the boom cylinder multi-way valve group, and the thrust cylinder reverse thrust pressure control valve is connected to the oil inlet pipeline of the breaker hammer thrust cylinder.

[0012] The crushing thrust pressure of the breaker hammer thrust cylinder is controlled by the thrust pressure control valve. The reverse thrust pressure of the breaker hammer thrust cylinder is controlled by the thrust cylinder reverse thrust pressure control valve. The thrust pressure control valve and the thrust cylinder reverse thrust pressure control valve are isolated by the thrust check valve. In this way, different thrust and reverse thrust pressure values ​​can be set according to different rock hardnesses, and the minimum thrust and reverse thrust pressure can be set while meeting the rock breaking effect, thereby reducing the reverse thrust vibration of the boom and the whole machine and prolonging the service life.

[0013] As a preferred solution of the present invention, the control unit of the boom cylinder multi-way valve group includes a main valve core, a secondary relief valve and an oil replenishment one-way valve, and the main valve core is an O-type function.

[0014] The boom cylinder remains stationary during the crushing operation, and the main valve core of the boom cylinder multi-way valve group is an O-type function, that is, the four oil ports of its PTAB are all closed, so that the large and small chambers of the boom cylinder maintain the mid-position closed function when they are not moving in the mid-position. At the same time, the large and small chambers are respectively provided with secondary relief valves and oil replenishment check valves. When the boom cylinder is subjected to the counter-impact force of the breaker hammer to form an internal high-frequency pressure shock, the secondary relief valve can be quickly opened to quickly unload the peak pressure and protect the boom cylinder and the boom from the peak pressure shock; the oil replenishment check valve can quickly replenish oil when the boom cylinder is passively extended and retracted to prevent air from entering the boom cylinder.

[0015] As a preferred embodiment of the present invention, the breaker hammer control valve group includes an oil inlet pipeline and an oil return pipeline, the oil inlet of the oil inlet pipeline is connected to the thrust check valve through a pipeline, the oil outlet of the oil inlet pipeline is connected to the P port of the breaker hammer through a pipeline, the oil inlet of the return oil pipeline is connected to the T port of the breaker hammer through a pipeline, and the oil outlet of the return oil pipeline is connected to the oil tank through a pipeline.

[0016] As a preferred solution of the present invention, the oil inlet pipeline is connected to a pressure limiting valve through a pipeline, and the other end of the pressure limiting valve is connected to the oil return pipeline through a pipeline. The pressure limiting valve can limit the maximum pressure of the breaker and protect the system.

[0017] As a preferred embodiment of the present invention, the oil inlet pipeline is also connected to an oil inlet main valve core, a control pipeline is also connected between the oil inlet main valve core and the oil inlet pipeline, a pilot control valve is connected to the control pipeline, and the pilot control valve is also connected to the oil return pipeline through a pipeline. When the pilot control valve is not powered on, the control pipeline is connected to the oil inlet pipeline, and when the pilot control valve is powered on, the control pipeline is connected to the oil return pipeline. The oil inlet main valve core is a two-way logic cartridge valve, which can be opened quickly, and the small flow pressure loss of the oil circuit can reduce the system heating loss. The pilot control valve is a two-position three-way valve, which can control the opening and closing of the oil inlet main valve core.

[0018] As a preferred solution of the present invention, the oil return pipeline is connected with an oil return balance valve, which is also connected to the oil inlet pipeline through a pipeline. The oil return balance valve can enable the high-frequency hammer motor to be quickly closed, and different pressures can be adjusted to achieve a suitable closing time.

[0019] As a preferred solution of the present invention, an oil replenishment pipeline is connected between the oil inlet pipeline and the oil return pipeline, and an oil replenishment check valve is connected to the oil replenishment pipeline. The oil replenishment check valve can replenish oil to the motor oil inlet when the main valve is closed to prevent air from entering.

[0020] As a preferred solution of the present invention, the oil return pipeline is also connected with an oil return back pressure check valve, which is located on the side of the oil replenishment pipeline away from the breaker. The oil return back pressure check valve can ensure that the oil replenishment check valve has a certain oil replenishment pressure.

[0021] The breaker control valve group can realize quick opening and closing to reduce the idle hitting time of the breaker when it does not contact the rock, thereby reducing the vibration of the boom and the whole machine caused by idle hitting.

[0022] As a preferred solution of the present invention, one boom oil cylinder has two oil cylinder units, the two oil cylinder units are respectively connected to the same control unit through pipelines, and the piston rods of the two oil cylinder units are connected to the same boom. The boom that bears the maximum pressure is driven by the two oil cylinder units.

[0023] A breaker hammer type tunnel boring machine comprises a machine body, a crawler is installed at the bottom of the machine body, a multi-stage boom is connected to the machine body, a breaker hammer is connected to the output end of the boom, a piston rod of a breaker hammer propulsion cylinder is connected to the cylinder of the breaker hammer, piston rods of a plurality of boom cylinders are respectively connected to the multi-stage boom in a one-to-one correspondence, and a crawler travel cylinder is connected to a crawler motor through a pipeline.

[0024] The beneficial effects of the present invention are:

[0025] 1. The crushing thrust pressure of the breaker's thrust cylinder is controlled by the thrust pressure control valve. The reverse thrust pressure of the breaker's thrust cylinder is controlled by the thrust cylinder reverse thrust pressure control valve. The thrust pressure control valve and the thrust cylinder reverse thrust pressure control valve are isolated by a thrust check valve. In this way, different thrust and reverse thrust pressure values ​​can be set according to different rock hardnesses, and the minimum thrust and reverse thrust pressure can be set while meeting the rock breaking effect, thereby reducing the reverse thrust vibration of the boom and the entire machine and prolonging its service life.

[0026] 2. The boom cylinder remains stationary during the crushing operation. The main valve core of the boom cylinder multi-way valve group is an O-type function, so that the large and small chambers of the boom cylinder maintain the mid-position closed function when they are not moving in the mid-position. At the same time, the large and small chambers are respectively provided with secondary relief valves and oil replenishment check valves. When the boom cylinder is subjected to the counter-impact force of the breaker to form an internal high-frequency pressure shock, the secondary relief valve can be quickly opened to quickly unload the peak pressure and protect the boom cylinder and the boom from the peak pressure shock; the oil replenishment check valve can quickly replenish oil when the boom cylinder is passively extended and retracted to avoid air entering the boom cylinder. The boom cylinder can quickly eliminate the counter-impact pressure peak in the crushing operation through the function control valve to protect the boom.

[0027] 3. The breaker control valve group can realize quick opening and closing to reduce the idle hitting time of the breaker when it does not contact the rock, thereby reducing the vibration of the boom and the whole machine caused by idle hitting. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of an anti-shock hydraulic system;

[0029] Figure 2 It is a schematic diagram of the boom cylinder multi-way valve group.

[0030] In the figure: 1- hydraulic oil pump; 2- breaker hammer; 3- breaker hammer thrust cylinder; 4- boom cylinder; 5- boom cylinder multi-way valve group; 6- crawler travel cylinder; 7- oil tank; 8- shuttle valve; 9- thrust cylinder reverse thrust pressure control valve; 10- breaker hammer control valve group; 11- thrust check valve; 12- thrust pressure control valve; 5.1- main valve core; 5.2- secondary relief valve; 5.3- oil replenishment check valve; 10.1- oil inlet main valve core; 10.2- pilot control valve; 10.3- oil return balance valve; 10.4- oil replenishment check valve; 10.5- oil return back pressure check valve; 10.6- pressure limiting valve. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0033] like Figure 1 and Figure 2 As shown, the anti-shock hydraulic system of the breaker hammer type tunnel boring machine of this embodiment includes an oil tank 7, a hydraulic oil pump 1, a boom cylinder multi-way valve group 5, a breaker hammer control valve group 10, a breaker hammer 2, a breaker hammer propulsion cylinder 3, a plurality of boom cylinders 4 and two crawler travel cylinders 6. The hydraulic oil pump 1 is connected to the oil tank 7 through a pipeline, and the breaker hammer 2 is connected to the breaker hammer control valve group 10 through a pipeline.

[0034] It also includes a shuttle valve 8, which is connected to the S port of the hydraulic oil pump 1, the LS port of the boom cylinder multi-way valve group 5, and the LS port of the breaker hammer control valve group 10 through pipelines, and a propulsion pressure control valve 12 is connected to the pipeline between the shuttle valve 8 and the hydraulic oil pump 1;

[0035] The outlet of the hydraulic oil pump 1 is connected to a propulsion check valve 11 through a pipeline, and the outlet pipeline of the propulsion check valve 11 is divided into two routes, which are respectively connected to the P port of the boom cylinder multi-way valve group 5 and the P port of the breaker control valve group 10;

[0036] The boom cylinder multi-way valve group 5 includes several control units, and the breaker hammer thrust cylinder 3, several boom cylinders 4 and two crawler travel cylinders 6 are respectively connected to several control units of the boom cylinder multi-way valve group 5, and the oil inlet pipeline of the breaker hammer thrust cylinder 3 is connected to a thrust cylinder reverse thrust pressure control valve 9.

[0037] The crushing thrust pressure of the breaker thrust cylinder 3 is controlled by the thrust pressure control valve 12. The reverse thrust pressure generated by the breaker 2 on the breaker thrust cylinder 3 when the breaker is working is controlled by the thrust cylinder reverse thrust pressure control valve 9. The thrust pressure control valve 12 and the thrust cylinder reverse thrust pressure control valve 9 are isolated by the thrust check valve 11. In this way, different thrust pressure and reverse thrust pressure values ​​can be set according to different rock hardnesses, and the minimum thrust and reverse thrust pressure can be set while meeting the rock breaking effect, thereby reducing the reverse thrust vibration of the boom 6 and the whole machine and improving the service life.

[0038] For example, the thrust pressure is set to 5MPa and the reverse thrust pressure is set to 10MPa on rocks with low hardness; the thrust pressure is set to 10MPa and the reverse thrust pressure is set to 20MPa on rocks with medium hardness; the thrust pressure is set to 15MPa and the reverse thrust pressure is set to 30MPa on rocks with high hardness, etc. The thrust pressure control valve 12 and the thrust cylinder reverse thrust pressure control valve 9 can be electric proportional relief valves, making the pressure adjustment setting more convenient, or they can be pre-set in the control program. In actual use, you only need to select different control programs according to different rocks.

[0039] Furthermore, the control unit of the boom cylinder multi-way valve group 5 includes a main valve core 5.1, a secondary relief valve 5.2 and an oil replenishment check valve 5.3, and the main valve core 5.1 is an O-type function.

[0040] The boom oil cylinder 4 remains stationary during the crushing operation, and the main valve core 5.1 of the boom oil cylinder multi-way valve group 5 is an O-type function, that is, the four oil ports of its PTAB are all closed, so that the large and small chambers of the boom oil cylinder 4 maintain the middle position closing function when they are not moving in the middle position. At the same time, the large and small chambers are respectively provided with a secondary relief valve 5.2 and an oil replenishment check valve 5.3. When the boom oil cylinder 4 is subjected to the counter-impact force of the breaker 2 to form an internal high-frequency pressure shock, the secondary relief valve 5.2 can be quickly opened to quickly unload the peak pressure and protect the boom oil cylinder 4 and the boom from the peak pressure shock; the oil replenishment check valve 5.3 can quickly replenish oil when the boom oil cylinder 4 is passively extended and retracted to prevent air from entering the boom oil cylinder 4.

[0041] Specifically, the breaker hammer control valve group 10 includes an oil inlet pipeline and an oil return pipeline. The oil inlet of the oil inlet pipeline is connected to the thrust check valve 11 through a pipeline, the oil outlet of the oil inlet pipeline is connected to the P port of the breaker hammer 2 through a pipeline, the oil inlet of the return oil pipeline is connected to the T port of the breaker hammer 2 through a pipeline, and the oil outlet of the return oil pipeline is connected to the oil tank 7 through a pipeline.

[0042] The oil inlet pipeline is connected to a pressure limiting valve 10.6 through a pipeline, and the other end of the pressure limiting valve 10.6 is connected to the oil return pipeline through a pipeline. The pressure limiting valve 10.6 can limit the maximum pressure of the breaker 2 to protect the system.

[0043] The oil inlet pipeline is also connected to an oil inlet main valve core 10.1, and a control pipeline is also connected between the oil inlet main valve core 10.1 and the oil inlet pipeline. A pilot control valve 10.2 is connected to the control pipeline, and the pilot control valve 10.2 is also connected to the oil return pipeline through a pipeline. When the pilot control valve 10.2 is not powered on, the control pipeline is connected to the oil inlet pipeline, and when the pilot control valve 10.2 is powered on, the control pipeline is connected to the oil return pipeline. The oil inlet main valve core 10.1 is a two-way logic cartridge valve, which can be opened quickly. At the same time, the circulation pressure loss of the oil circuit is small, which can reduce the system heating loss. The pilot control valve 10.2 is a two-position three-way valve, which can control the opening and closing of the oil inlet main valve core 10.1.

[0044] The oil return pipeline is connected with an oil return balance valve 10.3, which is also connected to the oil inlet pipeline through a pipeline. The oil return balance valve 10.3 can enable the high-frequency hammer motor to be quickly closed, and different pressures can be adjusted to achieve a suitable closing time.

[0045] An oil replenishment pipeline is connected between the oil inlet pipeline and the oil return pipeline, and an oil replenishment check valve 5.3 is connected to the oil replenishment pipeline. The oil replenishment check valve 5.3 can replenish oil to the motor oil inlet when the main valve is closed to prevent air from entering.

[0046] The return oil pipeline is also connected to a return oil back pressure check valve 10.5, which is located on the side of the oil replenishment pipeline away from the breaker 2. The return oil back pressure check valve 10.5 can ensure that the oil replenishment check valve 5.3 has a certain oil replenishment pressure.

[0047] Therefore, the breaker control valve group 10 can realize fast opening and fast closing to reduce the idle striking time of the breaker 2 when it does not contact the rock, thereby reducing the vibration of the boom and the whole machine caused by the idle striking.

[0048] It should be noted that: P port is the pressure side port, T port is the oil tank 7 side port, S port is the oil suction port, and LS port is the load sensitive oil circuit control port.

[0049] One of the boom oil cylinders 4 has two oil cylinder units, the two oil cylinder units are respectively connected to the same control unit through pipelines, and the piston rods of the two oil cylinder units are connected to the same boom. The boom that bears the maximum pressure is driven by the two oil cylinder units.

[0050] The breaker hammer type tunnel boring machine of this embodiment includes a machine body, a crawler is installed at the bottom of the machine body, a multi-stage boom is connected to the machine body, a breaker hammer 2 is connected to the output end of the boom, a piston rod of a breaker hammer thrust cylinder 3 is connected to the cylinder of the breaker hammer 2, piston rods of a plurality of boom cylinders 4 are respectively connected to the multi-stage boom in a one-to-one correspondence, and a crawler travel cylinder 6 is connected to the crawler motor through a pipeline.

[0051] The present invention is not limited to the above-mentioned optional implementation modes. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that fall within the scope defined by the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A hydraulic system for crushing hammer type tunnel boring machine, characterized by: The invention comprises a hydraulic oil pump (1), a breaker hammer (2), a breaker hammer thrust cylinder (3) and a boom cylinder multi-way valve group (5); a thrust pressure control valve (12) is connected between the S port of the hydraulic oil pump (1) and the LS port of the boom cylinder multi-way valve group (5) via a pipeline; a thrust check valve (11) is connected between the outlet of the hydraulic oil pump (1) and the P port of the boom cylinder multi-way valve group (5) via a pipeline; the boom cylinder multi-way valve group (5) comprises a plurality of control units, the breaker hammer thrust cylinder (3) is connected to a control unit of the boom cylinder multi-way valve group (5), and a thrust cylinder reverse thrust pressure control valve (9) is connected to the oil inlet pipeline of the breaker hammer thrust cylinder (3).

2. The anti-shock hydraulic system of a breaker-type tunnel boring machine according to claim 1, characterized in that: The control unit of the boom oil cylinder multi-way valve group (5) comprises a main valve core (5.1), and the main valve core (5.1) is an O-type function.

3. The anti-shock hydraulic system of a breaker-type tunnel boring machine according to claim 1, characterized in that: It also includes an oil tank (7) and a breaker hammer control valve group (10), wherein the hydraulic oil pump (1) is connected to the oil tank (7) through a pipeline, and the breaker hammer (2) is connected to the breaker hammer control valve group (10) through a pipeline; it also includes a shuttle valve (8), which is connected to the S port of the hydraulic oil pump (1), the LS port of the boom cylinder multi-way valve group (5), and the LS port of the breaker hammer control valve group (10) through pipelines; and the outlet pipeline of the propulsion check valve (11) is divided into two routes, which are respectively connected to the P port of the boom cylinder multi-way valve group (5) and the P port of the breaker hammer control valve group (10).

4. The anti-shock hydraulic system of a breaker-type tunnel boring machine according to claim 3 is characterized in that: The breaker hammer control valve group (10) comprises an oil inlet pipeline and an oil return pipeline, the oil inlet of the oil inlet pipeline is connected to the propulsion check valve (11) through a pipeline, the oil outlet of the oil inlet pipeline is connected to the P port of the breaker hammer (2) through a pipeline, the oil inlet of the oil return pipeline is connected to the T port of the breaker hammer (2) through a pipeline, and the oil outlet of the oil return pipeline is connected to the oil tank (7) through a pipeline.

5. The anti-shock hydraulic system of a breaker-type tunnel boring machine according to claim 4, characterized in that: The oil inlet pipeline is connected to a pressure limiting valve (10.6) via a pipeline, and the other end of the pressure limiting valve (10.6) is connected to the oil return pipeline via a pipeline.

6. The anti-shock hydraulic system of a breaker-type tunnel boring machine according to claim 4, characterized in that: The oil inlet pipeline is also connected to an oil inlet main valve core (10.1), a control pipeline is also connected between the oil inlet main valve core (10.1) and the oil inlet pipeline, a pilot control valve (10.2) is connected to the control pipeline, and the pilot control valve (10.2) is also connected to the oil return pipeline through a pipeline. When the pilot control valve (10.2) is not powered on, the control pipeline is connected to the oil inlet pipeline, and when the pilot control valve (10.2) is powered on, the control pipeline is connected to the oil return pipeline.

7. The anti-shock hydraulic system of a breaker-type tunnel boring machine according to claim 4, characterized in that: The oil return pipeline is connected with an oil return balancing valve (10.3), and the oil return balancing valve (10.3) is also connected with the oil inlet pipeline through a pipeline.

8. The anti-shock hydraulic system of a breaker-type tunnel boring machine according to claim 4, characterized in that: An oil replenishment pipeline is connected between the oil inlet pipeline and the oil return pipeline, and an oil replenishment check valve (5.3) is connected to the oil replenishment pipeline.

9. The anti-shock hydraulic system of a breaker-type tunnel boring machine according to claim 8, characterized in that: The oil return pipeline is also connected to an oil return back pressure check valve (10.5), and the oil return back pressure check valve (10.5) is located on the side of the oil replenishment pipeline away from the breaker (2).

10. The anti-shock hydraulic system of a breaker-type tunnel boring machine according to any one of claims 1 to 9, characterized in that: It also comprises a plurality of arm support cylinders (4) and two crawler travel cylinders (6), wherein the plurality of arm support cylinders (4) and the two crawler travel cylinders (6) are respectively connected to a plurality of control units of the arm support cylinder multi-way valve group (5).

Images