A hydraulic lifting device for a dump truck

Abstract

The present invention discloses a hydraulic lifting device for a dump truck, which relates to the technical field of hydraulic lifting devices and includes a cross bar. A lifting mechanism is installed on the side wall of the cross bar, and the lifting mechanism is used to lift the cargo box of the dump truck. The lifting mechanism includes a first telescopic mechanism, a second telescopic mechanism and a third telescopic mechanism. The third telescopic mechanism includes a second hinge block, the second hinge block is sleeved outside the cross bar, and the second hinge block is rotatably connected to the cross bar. A sleeve is fixedly connected to the top of the second hinge block, and a damping mechanism is sleeved in the sleeve, etc. In the present invention, a damping mechanism is designed in the third telescopic mechanism. When the lifting mechanism loses pressure, the sliding cylinder drives the first cylinder body to move downward, squeezing the hydraulic oil in the second cylinder body. The hydraulic oil flows between the cylinder body and the groove body through small-diameter flow holes, increasing the flow resistance and forming a damping effect. The volume of the groove body is larger than that of the cylinder body. When the hydraulic oil flows in, it compresses the air in the groove body, further enhancing the damping effect.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic lifting devices, and particularly to a hydraulic lifting device for dump trucks. Background Art

[0002] Dump trucks, as a special type of transport vehicle, play an indispensable role in fields such as logistics, construction, and mining. It has the function of automatically loading and unloading goods. Through its unique hydraulic cylinder system, it can quickly lift the cargo box to a certain height to achieve rapid dumping of goods, thus greatly improving work efficiency. At the same time, the cargo box of a dump truck is usually designed with a large capacity, capable of transporting a large amount of materials at one time, meeting the needs of different industries for transporting a large amount of materials.

[0003] However, despite the many advantages of dump trucks in the transportation field, their hydraulic cylinder systems often face various failure risks. Among them, the problem of rapid retraction of the hydraulic cylinder due to pressure loss failure is particularly prominent. When the hydraulic cylinder fails due to pressure loss, the cargo box that should be lifted smoothly will suddenly lose support and quickly fall. Due to the large weight and volume of the cargo box itself, this rapid fall is extremely likely to cause the cargo box to collide with the body of the dump truck. Such a collision will not only cause serious damage to the cargo box and the vehicle, but may even lead to safety accidents, posing a threat to the personal safety of the driver and surrounding personnel.

[0004] The purpose of the present invention is to solve the problem of rapid retraction of the hydraulic cylinder of a dump truck due to pressure loss failure, and to avoid the problem of damage caused by the collision of the cargo box with the dump truck itself. Summary of the Invention

[0005] In order to solve the problem of rapid retraction of the hydraulic cylinder of a dump truck due to pressure loss failure, and to avoid the problem of damage caused by the collision of the cargo box with the dump truck itself, the present invention adopts the following technical solutions:

[0006] A hydraulic lifting device for a dump truck includes a cross bar, and a lifting mechanism is installed on the side wall of the cross bar, and the lifting mechanism is used to lift the cargo box of the dump truck;

[0007] The lifting mechanism includes a first telescopic mechanism, a second telescopic mechanism, and a third telescopic mechanism. The third telescopic mechanism includes a second hinge block. The second hinge block is sleeved outside the cross bar, and the second hinge block is rotatably connected to the cross bar. A sleeve is fixedly connected to the top of the second hinge block, and a damping mechanism is sleeved inside the sleeve, and the damping mechanism is fixedly connected to the top of the second hinge block;

[0008] The damping mechanism includes a second cylinder body. A groove is formed in the second cylinder body. A plurality of flow holes are formed in the inner cavity side wall of the second cylinder body. The inner cavity of the second cylinder body is communicated with the groove through the flow holes. The volume of the groove is larger than that of the inner cavity of the second cylinder body. The inner cavity of the second cylinder body is filled with hydraulic oil. A cylinder cover is arranged at the top of the second cylinder body. The cylinder cover is threadedly connected with the second cylinder body;

[0009] The second telescopic mechanism includes a sliding cylinder. A plurality of through holes are formed in the top of the sliding cylinder. A fourth piston is fixedly connected to the bottom end of the sliding cylinder. The sliding cylinder and the fourth piston are both sleeved in a sleeve. The fourth piston is slidably connected with the inner cavity of the sleeve. A plurality of liquid infusion grooves are formed in the bottom of the sliding cylinder. A first cylinder body is fixedly connected to the top of the inner cavity of the sliding cylinder. The first cylinder body is filled with hydraulic oil. A second piston is fixedly connected to the bottom of the first cylinder body. One end of the first cylinder body and the second piston both pass through the cylinder cover and are sleeved in the second cylinder body. The second piston is slidably connected with the inner cavity of the second cylinder body;

[0010] The first telescopic mechanism includes a first piston. The first piston is sleeved outside the first cylinder body. The first piston is slidably connected with the first cylinder body. The first piston is slidably connected with the inner wall of the sliding cylinder. A plurality of support rods are fixedly connected to the top of the first piston. One end of the support rod passes through the through hole and is arranged outside the sliding cylinder. The top end of the support rod is fixedly connected with a first hinge block. A sliding rod is fixedly connected to the bottom of the first hinge block. The sliding rod includes a rod body and a third piston. The third piston is fixedly connected to the bottom end of the rod body. One end of the rod body and the third piston both penetrate through the top of the sliding cylinder and the first cylinder body and are arranged in the first cylinder body. The third piston is slidably connected with the inner cavity of the first cylinder body. A plurality of through grooves are formed in the third piston.

[0011] For a hydraulic lifting device for a dump truck as described above, buffer mechanisms are installed at both ends of the cross bar. The buffer mechanism includes a base. The base is fixedly connected with the cross bar. An air pump is installed in the base. An air inlet pipe is fixedly connected to the air outlet of the air pump. One end of the air inlet pipe penetrates through the side wall of the base and is arranged outside the base. A one-way air valve is installed in the air inlet pipe. A support mechanism is fixedly connected to the top of the base.

[0012] For a hydraulic lifting device for a dump truck as described above, the support mechanism includes a pillar. The pillar is fixedly connected with the base. An air bag is fixedly connected to the top of the pillar. One end of the air inlet pipe penetrates through the side wall of the pillar and is arranged in the pillar. An exhaust valve is installed on the side wall of the pillar.

[0013] A hydraulic lifting device for a dump truck as described above, wherein a telescopic rod is sleeved inside the pillar, the bottom end of the telescopic rod is fixedly connected to the top of the base, and the top end of the telescopic rod is fixedly connected to the top of the inner cavity of the airbag.

[0014] A hydraulic lifting device for a dump truck as described above, wherein a rubber pad is fixedly connected to the top of the airbag, and the rubber pad is used to protect the top of the airbag.

[0015] A hydraulic lifting device for a dump truck as described above, wherein the air pump is electrically connected to a controller. Programs for controlling the air pumping of the air pump and the air pumping time are written in the controller. Programs for controlling the input and extraction of hydraulic oil into and out of the sleeve are written in the controller. Programs for controlling the opening and closing of the exhaust valve are written in the controller. The controller is electrically connected to a control panel, and the control panel is used to control each program of the controller.

[0016] A hydraulic lifting device for a dump truck as described above, wherein the airbag is made of canvas.

[0017] A hydraulic lifting device for a dump truck as described above, wherein a cylinder head covers the top of the sleeve, and the cylinder head is threadedly connected to the sleeve.

[0018] A hydraulic lifting device for a dump truck as described above, wherein a flange is sleeved outside the sleeve, the flange is fixedly connected to the sleeve, and a plurality of threaded holes are provided in both the flange and the cylinder head. Bolts are sleeved in the threaded holes, and the cylinder head and the flange are fixedly connected by the bolts.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. In the present invention, a damping mechanism is designed in the third telescopic mechanism. When the lifting mechanism loses pressure, the sliding cylinder drives the first cylinder body to move downward, squeezing the hydraulic oil in the second cylinder body. The hydraulic oil flows between the cylinder body and the groove body through small-diameter flow holes, increasing the flow resistance and forming a damping effect. The volume of the groove body is larger than that of the cylinder body. When the hydraulic oil flows in, it compresses the air in the groove body, further enhancing the damping effect. This design effectively slows down the descending speed of the cargo box, prevents collisions, and improves safety.

[0021] 2. In the present invention, when the first telescopic mechanism loses pressure, the sliding rod drives the third piston to slide down in the first cylinder body filled with hydraulic oil. The through grooves on the piston allow the hydraulic oil to flow. Since the diameter of the through grooves is small, the flow resistance is increased, thereby forming a damping effect. When the hydraulic cylinder loses pressure, this design effectively slows down the retracting speed of the first telescopic mechanism.

[0022] 3. In the present invention, when the lifting mechanism is controlled by the control panel to lift the cargo box, the air pump will start synchronously and pump air into the strut, causing the airbag to expand. The air pumping time of the air pump is controlled by a program to avoid damage to the airbag. After the airbag expands, it is higher than the lifting mechanism. When controlling the lifting mechanism to retract, the exhaust valve is opened synchronously, and the airbag deflates and returns to its original state. When the lifting mechanism fails, the exhaust valve is not opened, and the airbag remains inflated to provide buffering for the cargo box and reduce collision damage.

[0023] In summary, the present invention solves the problem of rapid retraction of the hydraulic cylinder of the dump truck due to malfunction and pressure loss, and avoids the problem of damage caused by the collision between the cargo box and the dump truck itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0025] Figure 1 is a schematic structural diagram of a hydraulic lifting device for a dump truck according to the present invention;

[0026] Figure 2 is a sectional view of the lifting mechanism of a hydraulic lifting device for a dump truck according to the present invention;

[0027] Figure 3 is a schematic structural diagram of the first telescopic mechanism of a hydraulic lifting device for a dump truck according to the present invention;

[0028] Figure 4 is a sectional view of the second telescopic mechanism of a hydraulic lifting device for a dump truck according to the present invention;

[0029] Figure 5 is a schematic structural diagram of the sliding rod of a hydraulic lifting device for a dump truck according to the present invention;

[0030] Figure 6 is a sectional view of the third telescopic mechanism of a hydraulic lifting device for a dump truck according to the present invention;

[0031] Figure 7 is a sectional view of the damping mechanism of a hydraulic lifting device for a dump truck according to the present invention;

[0032] Figure 8 is a schematic structural diagram of the cylinder head of a hydraulic lifting device for a dump truck according to the present invention;

[0033] Figure 9 is a schematic structural diagram of the buffer mechanism of a hydraulic lifting device for a dump truck according to the present invention;

[0034] Figure 10 is a schematic structural diagram of the base of a hydraulic lifting device for a dump truck according to the present invention;

[0035] Figure 11 This is a schematic structural diagram of a support mechanism for a hydraulic lifting device of a dump truck according to the present invention;

[0036] Figure 12 This is a control system block diagram of an air pump for a hydraulic lifting device of a dump truck according to the present invention.

[0037] Reference numerals in the figure: 1, cross bar; 2, lifting mechanism; 201, first telescopic mechanism; 202, second telescopic mechanism; 203, third telescopic mechanism; 204, first piston; 205, support rod; 206, first hinge block; 207, second piston; 208, first cylinder body; 209, through hole; 210, sliding rod; 211, rod body; 212, third piston; 213, through groove; 214, sleeve; 215, flange; 216, cylinder head; 217, second hinge block; 218, hydraulic oil inlet and outlet pipe; 219, damping mechanism; 220, second cylinder body; 221, groove body; 222, circulation hole; 223, cylinder cover; 225, infusion groove; 226, fourth piston; 227, sliding cylinder; 3, buffer mechanism; 301, base; 302, support mechanism; 303, exhaust valve; 304, intake pipe; 305, one-way air valve; 306, air pump; 307, support column; 308, airbag; 309, rubber pad; 310, telescopic rod. Specific embodiments

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0039] Embodiment 1: This embodiment provides a hydraulic lifting device for a dump truck. Refer to Figure 1-11 , which includes a cross bar 1. A lifting mechanism 2 is installed on the side wall of the cross bar 1. The lifting mechanism 2 is used to lift the cargo box of the dump truck.

[0040] The lifting mechanism 2 includes a first telescopic mechanism 201, a second telescopic mechanism 202, and a third telescopic mechanism 203. The third telescopic mechanism 203 includes a second hinge block 217. The second hinge block 217 is sleeved outside the cross bar 1. The second hinge block 217 is rotatably connected to the cross bar 1. The top of the second hinge block 217 is fixedly connected to a sleeve 214. A damping mechanism 219 is sleeved inside the sleeve 214. The damping mechanism 219 is fixedly connected to the top of the second hinge block 217.

[0041] The damping mechanism 219 includes a second cylinder body 220. The second cylinder body 220 is provided with a groove 221. A number of flow holes 222 are provided on the inner cavity side wall of the second cylinder body 220. The inner cavity of the second cylinder body 220 is communicated with the groove 221 through the flow holes 222. The volume of the groove 221 is larger than that of the inner cavity of the second cylinder body 220. The inner cavity of the second cylinder body 220 is filled with hydraulic oil. A cylinder cover 223 is arranged at the top of the second cylinder body 220. The cylinder cover 223 is threadedly connected to the second cylinder body 220.

[0042] The second telescopic mechanism 202 includes a sliding cylinder 227. A number of through holes 209 are provided at the top of the sliding cylinder 227. A fourth piston 226 is fixedly connected to the bottom end of the sliding cylinder 227. Both the sliding cylinder 227 and the fourth piston 226 are sleeved in a sleeve 214. The fourth piston 226 is slidably connected to the inner cavity of the sleeve 214. A number of liquid infusion grooves 225 are provided at the bottom of the sliding cylinder 227. A first cylinder body 208 is fixedly connected to the top of the inner cavity of the sliding cylinder 227. The first cylinder body 208 is filled with hydraulic oil. A second piston 207 is fixedly connected to the bottom of the first cylinder body 208. One end of the first cylinder body 208 and the second piston 207 both pass through the cylinder cover 223 and are sleeved in the second cylinder body 220. The second piston 207 is slidably connected to the inner cavity of the second cylinder body 220. A cylinder head 216 covers the top of the sleeve 214. The cylinder head 216 is threadedly connected to the sleeve 214. A flange 215 is sleeved outside the sleeve 214. The flange 215 is fixedly connected to the sleeve 214. A number of threaded holes are provided on both the flange 215 and the cylinder head 216. Bolts are sleeved in the threaded holes. The cylinder head 216 and the flange 215 are fixedly connected through the bolts.

[0043] The first telescopic mechanism 201 includes a first piston 204. The first piston 204 is sleeved outside the first cylinder body 208. The first piston 204 is slidably connected to the first cylinder body 208. The first piston 204 is slidably connected to the inner wall of the sliding cylinder 227. A number of support rods 205 are fixedly connected to the top of the first piston 204. One end of the support rod 205 passes through the through hole 209 and is arranged outside the sliding cylinder 227. The top end of the support rod 205 is fixedly connected to a first hinge block 206. A sliding rod 210 is fixedly connected to the bottom of the first hinge block 206. The sliding rod 210 includes a rod body 211 and a third piston 212. The third piston 212 is fixedly connected to the bottom end of the rod body 211. One end of the rod body 211 and the third piston 212 both penetrate through the top of the sliding cylinder 227 and the first cylinder body 208 and are arranged in the first cylinder body 208. The third piston 212 is slidably connected to the inner cavity of the first cylinder body 208. A number of through grooves 213 are provided on the third piston 212.

[0044] In the specific implementation process, such as Figures 1 to 11As shown in the figure, the lifting mechanism 2 is composed of a first telescopic mechanism 201, a second telescopic mechanism 202, and a third telescopic mechanism 203. These telescopic mechanisms achieve telescoping through the pressure change of hydraulic oil, thereby completing the lifting and lowering operations of the dump truck cargo box.

[0045] A damping mechanism 219 is designed in the third telescopic mechanism 203. When the lifting mechanism 2 loses pressure, the sliding cylinder 227 drives the first cylinder body 208 to move downward. The first cylinder body 208 squeezes the hydraulic oil in the inner cavity of the second cylinder body 220. When the hydraulic oil in the inner cavity of the second cylinder body 220 is subjected to an external force, the hydraulic oil can flow between the second cylinder body 220 and the groove body 221 through the flow hole 222. The diameter of the flow hole 222 is specially designed to be small, which is to increase the resistance of the hydraulic oil during the flowing process, thereby forming an effective damping effect. Since the volume of the groove body 221 is larger than the inner cavity of the second cylinder body 220, when the hydraulic oil flows from the second cylinder body 220 to the groove body 221 through the flow hole 222, the hydraulic oil compresses the air in the groove body 221. This compression process further increases the flow resistance of the hydraulic oil, thereby further improving the effective damping effect. This damping effect is particularly important when the hydraulic cylinder loses pressure. It can effectively slow down the descending speed of the cargo box and prevent the cargo box from colliding with the dump truck body.

[0046] When the first telescopic mechanism 201 loses pressure and moves downward, it will drive the sliding rod 210 to move downward. When the sliding rod 210 moves downward, the third piston 212 slides in the first cylinder body 208. Since a number of through grooves 213 are provided on the third piston 212, when the third piston 212 moves downward, the hydraulic oil in the first cylinder body 208 flows through the through grooves 213. Since the diameter of the through grooves 213 is small, this increases the resistance of the hydraulic oil during the flowing process, thereby playing a damping role. In the case of the hydraulic cylinder losing pressure, it can effectively slow down the retracting speed of the first telescopic mechanism 201.

[0047] Embodiment 2: In Embodiment 1, there is still a problem that the lifting mechanism 2 malfunctions or disconnects, and the cargo box of the dump truck descends rapidly and collides with the dump truck itself, resulting in damage to both sides. Therefore, on the basis of Embodiment 1, this embodiment further includes:

[0048] The support mechanism 302 includes a support column 307. The support column 307 is fixedly connected to the base 301. The top of the support column 307 is fixedly connected with an airbag 308. The material of the airbag 308 is canvas. The top of the airbag 308 is fixedly connected with a rubber pad 309. The rubber pad 309 is used to protect the top of the airbag 308. One end of the air inlet pipe 304 penetrates through the side wall of the support column 307 and is arranged inside the support column 307. An exhaust valve 303 is installed on the side wall of the support column 307. A telescopic rod 310 is sleeved inside the support column 307. The bottom end of the telescopic rod 310 is fixedly connected to the top of the base 301, and the top end of the telescopic rod 310 is fixedly connected to the top of the inner cavity of the airbag 308.

[0049] The air pump 306 is electrically connected to a controller. Programs for controlling the air pumping of the air pump 306 and the air pumping time are written in the controller. Programs for controlling the input and extraction of hydraulic oil into and from the sleeve 214 are written in the controller. Programs for controlling the opening and closing of the exhaust valve 303 are written in the controller. The controller is electrically connected to a control panel, and the control panel is used to control each program of the controller.

[0050] During the specific implementation process, such as Figure 1 , Figure 9 , Figure 10 , Figure 11 and Figure 12 shown, during normal use, the input and extraction of hydraulic oil into and from the sleeve 214 are controlled through the control panel, thereby realizing the control of the lifting and lowering operations of the lifting mechanism 2 on the cargo box. When the lifting mechanism 2 is controlled through the control panel to lift the cargo box, the program for controlling the air pumping of the air pump 306 synchronously controls the start of the air pump 306, and the program for controlling the opening and closing of the exhaust valve 303 synchronously closes the exhaust valve 303. The air pump 306 pumps air into the support column 307, and the airbag 308 is inflated by the gas. The air pumping time of the air pump 306 is controlled by the air pumping time program to avoid bursting the airbag 308. After the airbag 308 is inflated and expanded, it is higher than the height after the lifting mechanism 2 retracts. When the lifting mechanism 2 is controlled through the control panel to retract, the program for controlling the opening and closing of the exhaust valve 303 synchronously operates to open the exhaust valve 303, and the airbag 308 deflates and returns to its original state. When the lifting mechanism 2 fails or disconnects and the cargo box of the dump truck quickly descends, since the lifting mechanism 2 is not controlled through the control panel, the program for controlling the opening and closing of the exhaust valve 303 will not operate to open the exhaust valve 303. Therefore, the airbag 308 is in an inflated state, and the cargo box first contacts the airbag 308 during the falling process. The airbag 308 provides a buffer for the cargo box and the dump truck, thereby reducing the damage caused by the collision between the cargo box and the dump truck.

[0051] Specifically, the working principle of the present invention is as follows:

[0052] When in use, this device is installed on the dump truck, located on one side of the cargo box of the dump truck, between the cargo box and the driver's cab. The lifting mechanism 2 is composed of a first telescopic mechanism 201, a second telescopic mechanism 202, and a third telescopic mechanism 203. These telescopic mechanisms achieve telescoping through the pressure change of hydraulic oil, thereby completing the lifting and lowering operations of the cargo box of the dump truck.

[0053] When the lifting mechanism 2 loses pressure, the sliding cylinder 227 drives the first cylinder body 208 to move downward. The first cylinder body 208 squeezes the hydraulic oil in the inner cavity of the second cylinder body 220. When the hydraulic oil in the inner cavity of the second cylinder body 220 is subjected to an external force, the hydraulic oil can flow between the second cylinder body 220 and the groove body 221 through the flow holes 222. The diameter of the flow holes 222 is specially designed to be small, which is to increase the resistance of the hydraulic oil during the flowing process, thereby forming an effective damping effect. Since the volume of the groove body 221 is larger than the inner cavity of the second cylinder body 220, when the hydraulic oil flows from the second cylinder body 220 to the groove body 221 through the flow holes 222, the hydraulic oil compresses the air in the groove body 221. This compression process further increases the flow resistance of the hydraulic oil, thereby further improving the effective damping effect. This damping effect is particularly important when the hydraulic cylinder loses pressure. It can effectively slow down the descending speed of the cargo box and prevent the cargo box from colliding with the body of the dump truck.

[0054] When the first telescopic mechanism 201 loses pressure and moves downward, it will drive the sliding rod 210 to move downward. When the sliding rod 210 moves downward, the third piston 212 slides in the first cylinder body 208. Since a number of through grooves 213 are provided on the third piston 212, when the third piston 212 moves downward, the hydraulic oil in the first cylinder body 208 flows through the through grooves 213. Since the diameter of the through grooves 213 is small, this increases the resistance of the hydraulic oil during the flowing process, thereby playing a damping role. In the case of the hydraulic cylinder losing pressure, it can effectively slow down the retracting speed of the first telescopic mechanism 201.

[0055] When the lifting mechanism 2 is controlled by the control panel to lift the cargo box, the program for controlling the air pump 306 to pump air synchronously controls the air pump 306 to start, and the program for controlling the switch of the exhaust valve 303 synchronously closes the exhaust valve 303. The air pump 306 pumps air into the support column 307, and the airbag 308 is inflated by the gas. The pumping time of the air pump 306 is controlled by the pumping time program to avoid bursting the airbag 308. After the airbag 308 is inflated and expanded, it is higher than the height after the lifting mechanism 2 retracts. When the lifting mechanism 2 is controlled by the control panel to retract, the program for controlling the switch of the exhaust valve 303 synchronously opens the exhaust valve 303, and the airbag 308 deflates and returns to its original state. When the lifting mechanism 2 fails or disconnects and the cargo box of the dump truck descends rapidly, since the lifting mechanism 2 is not controlled by the control panel, the program for controlling the switch of the exhaust valve 303 will not operate to open the exhaust valve 303. Therefore, the airbag 308 is in an inflated state. During the process of the cargo box falling, it first contacts the airbag 308, and the airbag 308 buffers the cargo box and the dump truck, thereby reducing the damage caused by the collision between the cargo box and the dump truck.

[0056] In summary, the present invention solves the problem of rapid retraction of the hydraulic cylinder of the dump truck due to a fault and pressure loss, and avoids the problem of damage caused by the collision between the cargo box and the dump truck itself.

[0057] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A hydraulic lifting device for a dump truck, comprising a cross bar (1), characterized in that: A lifting mechanism (2) is installed on the side wall of the cross bar (1), and the lifting mechanism (2) is used to lift the cargo box of the dump truck; The lifting mechanism (2) includes a first telescopic mechanism (201), a second telescopic mechanism (202) and a third telescopic mechanism (203). The third telescopic mechanism (203) includes a second hinge block (217). The second hinge block (217) is sleeved outside the cross bar (1). The second hinge block (217) is rotatably connected to the cross bar (1). A sleeve (214) is fixedly connected to the top of the second hinge block (217). A damping mechanism (219) is sleeved in the sleeve (214). The damping mechanism (219) is fixedly connected to the top of the second hinge block (217); The damping mechanism (219) includes a second cylinder body (220). The second cylinder body (220) is provided with a groove body (221). A plurality of flow holes (222) are formed in the inner cavity side wall of the second cylinder body (220). The inner cavity of the second cylinder body (220) is communicated with the groove body (221) through the flow holes (222). The volume of the groove body (221) is larger than the inner cavity of the second cylinder body (220). The inner cavity of the second cylinder body (220) is filled with hydraulic oil. A cylinder cover (223) is arranged at the top of the second cylinder body (220). The cylinder cover (223) is threadedly connected to the second cylinder body (220); The second telescopic mechanism (202) includes a sliding cylinder (227). A plurality of through holes (209) are formed in the top of the sliding cylinder (227). A fourth piston (226) is fixedly connected to the bottom end of the sliding cylinder (227). The sliding cylinder (227) and the fourth piston (226) are both sleeved in the sleeve (214). The fourth piston (226) is slidably connected to the inner cavity of the sleeve (214). A plurality of infusion grooves (225) are formed in the bottom of the sliding cylinder (227). A first cylinder body (208) is fixedly connected to the top of the inner cavity of the sliding cylinder (227). The first cylinder body (208) is filled with hydraulic oil. A second piston (207) is fixedly connected to the bottom of the first cylinder body (208). One end of the first cylinder body (208) and the second piston (207) both pass through the cylinder cover (223) and are sleeved in the second cylinder body (220). The second piston (207) is slidably connected to the inner cavity of the second cylinder body (220); The first telescopic mechanism (201) includes a first piston (204). The first piston (204) is sleeved outside a first cylinder body (208). The first piston (204) is slidably connected to the first cylinder body (208). The first piston (204) is slidably connected to the inner wall of a sliding cylinder (227). A plurality of support rods (205) are fixedly connected to the top of the first piston (204). One end of the support rod (205) passes through a through hole (209) and is arranged outside the sliding cylinder (227). The top end of the support rod (205) is fixedly connected to a first hinge block (206). A sliding rod (210) is fixedly connected to the bottom of the first hinge block (206). The sliding rod (210) includes a rod body (211) and a third piston (212). The third piston (212) is fixedly connected to the bottom end of the rod body (211). One end of the rod body (211) and the third piston (212) both penetrate through the tops of the sliding cylinder (227) and the first cylinder body (208) and are arranged inside the first cylinder body (208). The third piston (212) is slidably connected to the inner cavity of the first cylinder body (208). The third piston (212) is provided with a plurality of through slots (213). Buffer mechanisms (3) are installed at both ends of the cross bar (1). The buffer mechanism (3) includes a base (301). The base (301) is fixedly connected to the cross bar (1). An air pump (306) is installed inside the base (301). An air inlet pipe (304) is fixedly connected to the air outlet of the air pump (306). One end of the air inlet pipe (304) penetrates through the side wall of the base (301) and is arranged outside the base (301). A one-way air valve (305) is installed inside the air inlet pipe (304). A support mechanism (302) is fixedly connected to the top of the base (301). The support mechanism (302) includes a support column (307). The support column (307) is fixedly connected to the base (301). An airbag (308) is fixedly connected to the top of the support column (307). One end of the air inlet pipe (304) penetrates through the side wall of the support column (307) and is arranged inside the support column (307). An exhaust valve (303) is installed on the side wall of the support column (307). A telescopic rod (310) is sleeved inside the support column (307). The bottom end of the telescopic rod (310) is fixedly connected to the top of the base (301). The top end of the telescopic rod (310) is fixedly connected to the top of the inner cavity of the airbag (308). A rubber pad (309) is fixedly connected to the top of the airbag (308). The rubber pad (309) is used to protect the top of the airbag (308). The air pump (306) is electrically connected to a controller. A program for controlling the air pumping of the air pump (306) and the air pumping time is written in the controller. A program for controlling the input and extraction of hydraulic oil into and from a sleeve (214) is written in the controller. A program for controlling the opening and closing of the exhaust valve (303) is written in the controller. The controller is electrically connected to a control panel. The control panel is used to control each program of the controller.

2. The hydraulic lifting device for a dump truck according to claim 1, characterized in that: The material of the airbag (308) is canvas.

3. A hydraulic lifting device for a dump truck according to claim 1, characterized in that: The top of the sleeve (214) is covered with a cylinder head (216), and the cylinder head (216) is threadedly connected to the sleeve (214).

4. The hydraulic lifting device for a dump truck according to claim 3, characterized in that: A flange (215) is sleeved outside the sleeve (214), and the flange (215) is fixedly connected to the sleeve (214). A number of threaded holes are provided in both the flange (215) and the cylinder head (216). Bolts are sleeved in the threaded holes, and the cylinder head (216) and the flange (215) are fixedly connected by the bolts.

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