Cab front suspension safety limiting mechanism and using method thereof

Abstract

The invention relates to the technical field of hydraulic overturning, in particular to a cab front suspension safety limiting mechanism which comprises a safety pull rod upper connecting arm. One end of the safety pull rod upper connecting arm is connected with a connecting bolt, and the other end of the safety pull rod upper connecting arm is connected with a limiting pin and a safety pull rod lower connecting arm; the safety pull rod lower connecting arm is connected with the limiting pin in a clamped mode, and the safety pull rod lower connecting arm is connected with a support. The support is connected with a frame; the connecting bolt is connected with the automobile front suspension upper support; the safety pull rod upper connecting arm comprises a corrugated section; the upper connecting arm of the safety pull rod comprises a corrugated section used for absorbing impact in the overturning and resetting stages, so that the service life of the hydraulic cylinder is prolonged; the limiting clamping groove in the lower connecting arm of the safety pull rod is clamped on the limiting pin, the cab is limited within the designed angle range, and the risk that the hydraulic cylinder is pulled out or fails is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic rollover, and in particular to a cab front suspension safety limiting mechanism. Background Art

[0002] Commercial vehicles (especially medium and heavy-duty trucks) widely adopt a flat-head design with the engine placed under the cab; the traditional cab disassembly and maintenance efficiency is low, and a hydraulic flip system is required to provide an inspection channel; after the center of gravity of the cab flips over the flip center of gravity, the cylinder will be subjected to a large impact at the moment of reaching the extension limit, the cylinder risk factor is amplified, the system life is affected, and the hydraulic cylinder is at risk of being pulled out or failing, resulting in the inability to control the flip angle of the cab; currently, the limit is limited by the arrangement of limit blocks, but due to the limitation of the arrangement space, the upper and lower limit blocks are small in size and low in load-bearing capacity, especially when the center of gravity of the cab flips over the flip center, the force on the limit block increases sharply, and the reliability is greatly reduced. In addition, there is a large impact when reaching the flip limit position or the cab falls back, which can easily cause damage to the flip cylinder and limit blocks.

[0003] After searching, the applicant found that the Chinese patent document with application number 202323482160.8 disclosed an electric cylinder hydraulic device of a car cab flipping device on December 20, 2023, including a cylinder body and a hydraulic rod, the interior of the cylinder body is slidably connected to the hydraulic rod, the interior of the hydraulic rod is provided with a deceleration mechanism, the exterior of the cylinder body is provided with a protective mechanism, one end of the hydraulic rod is fixedly connected to a rubber ring, and the end of the cylinder body is fixedly connected to a first fixed seat; the hydraulic rod drives the first support rod and the wedge block to move, and during the contact between the wedge block and the fixed block, the fixed block drives the wedge block to move, and the wedge block drives the first support rod to slide, the spring is compressed, and the end of the first support rod contacts the inner wall of the cylinder body to generate friction, thereby reducing the movement speed of the hydraulic rod. At the same time, the friction generated by the contact between the wedge block and the fixed block will also reduce the movement speed of the hydraulic rod. There are multiple moving blocks, so that the hydraulic rod is decelerated multiple times, which is convenient for controlling the descending speed of the hydraulic rod; this device also cannot solve the above technical problems.

[0004] Therefore, in order to improve or solve at least one of the above problems, it is necessary to provide a cab front suspension safety limiting mechanism that can effectively limit the cab lifting angle and reduce the impact during the rollover stage. Summary of the Invention

[0005] The object of the present invention is to provide a cab front suspension safety limiting mechanism which can effectively limit the lifting angle of the cab and reduce the impact during the rollover stage.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a cab front suspension safety limit mechanism, including a safety pull rod upper connecting arm; one end of the safety pull rod upper connecting arm is connected to a connecting bolt, and the other end of the safety pull rod upper connecting arm is connected to a limit pin and a safety pull rod lower connecting arm; the safety pull rod lower connecting arm is clamped with the limit pin, and the safety pull rod lower connecting arm is connected to a support; the support is connected to the vehicle frame; the connecting bolt is connected to the upper support of the vehicle front suspension; the safety pull rod upper connecting arm includes a corrugated section.

[0007] The upper connecting arm of the safety pull rod includes a first upper connecting arm and a second upper connecting arm; the connecting bolt is connected to the first upper connecting arm and the second upper connecting arm; the limit pin and the lower connecting arm of the safety pull rod are arranged between the first upper connecting arm and the second upper connecting arm.

[0008] A center gasket is provided between the first upper connecting arm and the second upper connecting arm; the first upper connecting arm and the second upper connecting arm are provided on the center gasket; an upper limit sleeve is provided on the side of the first upper connecting arm and the second upper connecting arm away from the center gasket; a first flat washer is provided between the upper limit sleeve and the first upper connecting arm and the second upper connecting arm; an upper mounting through hole is provided on the first upper connecting arm and the second upper connecting arm; the connecting bolt is sleeved in the upper limit sleeve, the upper mounting through hole, the center gasket and the first flat washer; the connecting bolt is connected with a connecting nut.

[0009] The limit pin is arranged on the end of the connecting arm on the safety pull rod away from the connecting bolt; the first upper connecting arm and the second upper connecting arm are both provided with a limit pin mounting hole; the end of the limit pin is arranged in the limit pin mounting hole; the end of the limit pin is connected to a second flat washer, and the limit pin is connected to a cotter pin.

[0010] A rotating sleeve mounting hole is provided on both the first upper connecting arm and the second upper connecting arm; the rotating sleeve mounting hole is provided on one side of the limit pin mounting hole; a rotating sleeve is provided in the rotating sleeve mounting hole; a first rotating hole is provided at the end of the lower connecting arm of the safety pull rod; the rotating sleeve is provided in the first rotating hole; the rotating sleeve is connected to a fixing bolt; a third flat washer is provided between the fixing bolt and the first upper connecting arm; the fixing bolt is connected to a fixing nut.

[0011] A limit slot is provided at the end of the lower connecting arm of the safety pull rod; a clamping section is provided on the limit pin; and the clamping section is arranged in the limit slot.

[0012] The support includes a support side plate; a support sleeve mounting hole is provided on the support side plate; a support sleeve is provided in the support sleeve mounting hole; a second rotation hole is provided at one end of the lower connecting arm of the safety pull rod away from the first rotation hole; the lower connecting arm of the safety pull rod is arranged between adjacent support side plates; the support sleeve is arranged in the second rotation hole; a bolt is connected to the support sleeve; a fourth flat washer is provided between the bolt and the support side plate; and a nut is connected to the bolt.

[0013] The upper support of the front suspension of the automobile includes a first side plate and a second side plate; the first side plate is arranged between the upper limit sleeve and the connecting bolt; the second side plate is arranged between the upper limit sleeve and the connecting nut; bolt holes are provided on both the first side plate and the second side plate; the connecting bolt is connected in the bolt hole.

[0014] A method for using the cab front suspension safety limit mechanism includes the following steps:

[0015] S1: Start the hydraulic cylinder; the piston rod of the hydraulic cylinder extends, pushing the cab to slowly flip upward around the rotating shaft; the upper connecting arm of the safety lever and the lower connecting arm of the safety lever rotate;

[0016] S2: When the cab is flipped to a set angle, the lower connecting arm of the safety pull rod is clamped on the limit pin through the limit clamping groove;

[0017] S3: When the maintenance or inspection work is completed, the piston rod of the hydraulic cylinder retracts, and the cab slowly and steadily returns to its initial position under the combined action of gravity and the piston rod; the upper connecting arm and the lower connecting arm of the safety rod rotate; the limit pin is removed from the limit slot; the upper connecting arm and the lower connecting arm of the safety rod are reset.

[0018] One end of the lower connecting arm of the safety rod rotates on the support, and the other end of the lower connecting arm of the safety rod rotates on the rotating sleeve; one end of the upper connecting arm of the safety rod rotates on the rotating sleeve, and the upper connecting arm of the safety rod rotates on the center gasket.

[0019] The beneficial effects of the present invention are:

[0020] The upper connecting arm of the safety pull rod of the present invention includes a corrugated section for absorbing the impact during the flipping and resetting stages, thereby extending the service life of the hydraulic cylinder;

[0021] After the center of gravity of the cab flips over the flip center, the hydraulic cylinder will be subjected to a large impact at the moment it reaches the extension limit, which may cause the cylinder barrel of the hydraulic cylinder to separate from the end cover, and the piston rod to break or fall out from the piston connection. Because the components of the cab front suspension safety limit mechanism are all metal parts and are rigidly connected, the limit slot on the lower connecting arm of the safety pull rod is stuck on the limit pin, limiting the cab to the designed angle range. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, in which:

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] Figure 2 It is an exploded view of the present invention.

[0025] Figure 3 for Figure 1 Cross-sectional view at AA.

[0026] Figure 4 for Figure 1 Cross-sectional view at BB.

[0027] Figure 5 for Figure 1 Cross-sectional view at CC.

[0028] Figure 6 It is a schematic diagram of the working state of the present invention.

[0029] The marks in the above figure are:

[0030] The following are marked in the figure:

[0031] 1. Safety tie rod upper connecting arm, 101. Corrugated section, 102. Center gasket, 103. First flat washer,

[0032] 2. Connecting bolts, 201. Connecting nuts,

[0033] 3. Limit pin, 301. Limit pin mounting hole, 302. Second flat washer, 303. Cotter pin, 304. Snap-fit ​​section,

[0034] 4. Safety pull rod lower connecting arm, 401. Rotating sleeve mounting hole, 402. Rotating sleeve, 403. First rotating hole, 404. Fixing bolt, 405. Third flat washer, 406. Fixing nut, 407. Limiting slot, 408. Second rotating hole,

[0035] 5. Support, 501. Support side plate, 502. Support sleeve mounting hole, 503. Support sleeve, 504. Bolt, 505. Fourth flat washer, 506. Nut,

[0036] 6. Automobile front suspension upper support, 601, first side plate, 602, second side plate, 603, bolt hole,

[0037] 7. First upper connecting arm, 701. Second upper connecting arm, 702. Upper limit sleeve, 703. Upper mounting through hole. DETAILED DESCRIPTION

[0038] The following is a further detailed description of the specific implementation methods of the present invention through the description of the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention and to facilitate their implementation.

[0039] Figure 1-6 The illustrated embodiment shows a cab front suspension safety limit mechanism, comprising a safety rod upper connecting arm 1; one end of the safety rod upper connecting arm 1 is connected to a connecting bolt 2, and the other end of the safety rod upper connecting arm 1 is connected to a limit pin 3 and a safety rod lower connecting arm 4; the safety rod lower connecting arm 4 is engaged with the limit pin 3, and is connected to a support 5; the support 5 is connected to the vehicle frame; the connecting bolt 2 is connected to the vehicle front suspension upper support 6; the safety rod upper connecting arm 1 comprises a corrugated section 101.

[0040] The upper connecting arm 1 of the safety pull rod includes a corrugated section 101, which is used to absorb the impact during the flipping and resetting stages, thereby extending the service life of the hydraulic cylinder; after the center of gravity of the cab flips over the flip center, the hydraulic cylinder will be subjected to a large impact at the moment of reaching the elongation limit, which may cause the hydraulic cylinder barrel to separate from the end cover, and the piston rod to break or fall out from the piston connection. Since the components of the cab front suspension safety limit mechanism are all metal parts and are rigidly connected, the lower connecting arm 4 of the safety pull rod is stuck on the limit pin 3, limiting the cab to the designed angle range.

[0041] The upper connecting arm 1 of the safety pull rod includes a first upper connecting arm 7 and a second upper connecting arm 701; the connecting bolt 2 is connected to the first upper connecting arm 7 and the second upper connecting arm 701; the limit pin 3 and the lower connecting arm 4 of the safety pull rod are arranged between the first upper connecting arm 7 and the second upper connecting arm 701.

[0042] The first upper connecting arm 7 and the second upper connecting arm 701 have the same structure and rotate synchronously; the limit pin 3 is fixedly connected between the first upper connecting arm 7 and the second upper connecting arm 701; the end of the lower connecting arm 4 of the safety pull rod can rotate between the first upper connecting arm 7 and the second upper connecting arm 701, and can be engaged with the limit pin 3.

[0043] A center gasket 102 is provided between the first upper connecting arm 7 and the second upper connecting arm 701; the first upper connecting arm 7 and the second upper connecting arm 701 are provided on the center gasket 102; the first upper connecting arm 7 and the second upper connecting arm 701 are both provided with an upper limit sleeve 702 on the side away from the center gasket 102; a first flat washer 103 is provided between the upper limit sleeve 702 and the first upper connecting arm 7 and the second upper connecting arm 701; an upper mounting through hole 703 is provided on the first upper connecting arm 7 and the second upper connecting arm 701; the connecting bolt 2 is sleeved in the upper limit sleeve 702, the upper mounting through hole 703, the center gasket 102 and the first flat washer 103; the connecting bolt 2 is connected with a connecting nut 201.

[0044] The cross-section of the center gasket 102 is T-shaped; the first upper connecting arm 7 and the second upper connecting arm 701 are both sleeved on the center gasket 102 and can rotate on the center gasket 102; both sides of the center gasket 102 are pressed against the first flat washer 103; the other side of the first flat washer 103 is pressed against the upper limit sleeve 702; the connecting bolt 2 is a hexagonal flange bolt; the center gasket 102 is a homemade safety pull rod gasket; the connecting nut 201 is a hexagonal flange nut.

[0045] The limit pin 3 is arranged on the end of the upper connecting arm 1 of the safety pull rod away from the connecting bolt 2; the first upper connecting arm 7 and the second upper connecting arm 701 are both provided with a limit pin mounting hole 301; the end of the limit pin 3 is arranged in the limit pin mounting hole 301; the end of the limit pin 3 is connected to the second flat washer 302, and the limit pin 3 is connected to the cotter pin 303.

[0046] One end of the limit pin 3 extends from the limit pin mounting hole 301 of the first upper connecting arm 7, and is sleeved on the second flat washer 302, and is connected to the cotter pin 303 at the outermost side; the other end of the limit pin 3 extends from the limit pin mounting hole 301 of the second upper connecting arm 701, and is sleeved on the second flat washer 302, and is connected to the cotter pin 303 at the outermost side; thereby, the limit pin 3 can be fixed between the first upper connecting arm 7 and the second upper connecting arm 701.

[0047] A rotating sleeve mounting hole 401 is provided on both the first upper connecting arm 7 and the second upper connecting arm 701; the rotating sleeve mounting hole 401 is provided on one side of the limit pin mounting hole 301; a rotating sleeve 402 is provided in the rotating sleeve mounting hole 401; a first rotating hole 403 is provided at the end of the lower connecting arm 4 of the safety pull rod; the rotating sleeve 402 is provided in the first rotating hole 403; the rotating sleeve 402 is connected to a fixing bolt 404; a third flat washer 405 is provided between the fixing bolt 404 and the first upper connecting arm 7; the fixing bolt 404 is connected to a fixing nut 406.

[0048] One end of the rotating sleeve 402 is inserted into the rotating sleeve mounting hole 401 of the first upper connecting arm 7; the other end of the rotating sleeve 402 is inserted into the rotating sleeve mounting hole 401 of the second upper connecting arm 701; the first upper connecting arm 7 and the second upper connecting arm 701 can rotate on the rotating sleeve 402; the lower connecting arm 4 of the safety pull rod is connected to the rotating sleeve 402 through the first rotating hole 403, so that it can rotate on the rotating sleeve 402; the fixing bolt 404 is a hexagonal head bolt; the fixing nut 406 is a hexagonal flange nut.

[0049] A limit slot 407 is provided at the end of the lower connecting arm 4 of the safety pull rod; a clamping section 304 is provided on the limit pin 3; and the clamping section 304 is arranged in the limit slot 407 .

[0050] The engaging section 304 and the limiting pin 3 are an integral structure.

[0051] The support 5 includes a support side plate 501; a support sleeve mounting hole 502 is provided on the support side plate 501; a support sleeve 503 is provided in the support sleeve mounting hole 502; a second rotation hole 408 is provided at the end of the lower connecting arm 4 of the safety pull rod away from the first rotation hole 403; the lower connecting arm 4 of the safety pull rod is arranged between adjacent support side plates 501; the support sleeve 503 is arranged in the second rotation hole 408; a bolt 504 is connected to the support sleeve 503; a fourth flat washer 505 is provided between the bolt 504 and the support side plate 501; and a nut 506 is connected to the bolt 504.

[0052] The lower connecting arm 4 of the safety pull rod is connected to the support sleeve 503 through the second rotating hole 408 and can rotate on the support sleeve 503; the bolt 504 is a hexagonal head bolt; and the nut 506 is a hexagonal flange nut.

[0053] The upper support 6 of the front suspension of the automobile includes a first side plate 601 and a second side plate 602; the first side plate 601 is arranged between the upper limit sleeve 702 and the connecting bolt 2; the second side plate 602 is arranged between the upper limit sleeve 702 and the connecting nut 201; bolt holes 603 are provided on both the first side plate 601 and the second side plate 602; the connecting bolt 2 is connected in the bolt hole 603.

[0054] The connecting bolt 2 passes through the bolt holes 603 on the first side plate 601 and the second side plate 602, and at the same time, the connecting bolt 2 is sleeved in the upper limit sleeve 702, the upper mounting through hole 703, the center gasket 102 and the first flat washer 103, connecting the device to the upper support 6 of the front suspension of the automobile.

[0055] A method for using a cab front suspension safety limit mechanism comprises the following steps:

[0056] S1: Start the hydraulic cylinder; the piston rod of the hydraulic cylinder extends, pushing the cab to slowly flip upward around the rotating shaft; the upper connecting arm 1 of the safety lever and the lower connecting arm 4 of the safety lever rotate;

[0057] S2: When the cab is flipped to the set angle, the lower connecting arm 4 of the safety rod is connected to the limit pin 3 through the limit slot 407;

[0058] S3: When the maintenance or inspection work is completed, the piston rod of the hydraulic cylinder retracts, and the cab slowly and steadily returns to its initial position under the combined action of gravity and the piston rod; the upper connecting arm 1 of the safety rod and the lower connecting arm 4 of the safety rod rotate; the limit pin 3 is removed from the limit slot 407; the upper connecting arm 1 of the safety rod and the lower connecting arm 4 of the safety rod are reset.

[0059] S1 includes:

[0060] Preparation stage: The driver turns on the cab flip control switch and rotates the flip lever on the hydraulic pump to the raised position to prepare for the operation of the hydraulic system.

[0061] Flipping stage: When the driver operates the control handle or button to issue a flipping command, the flow direction of the hydraulic oil is changed; the hydraulic oil enters the rodless chamber of the hydraulic cylinder under pressure, pushing the piston outward. Since the piston is connected to the front suspension flipping mechanism of the cab, the extension of the piston pushes the cab to slowly flip upward around the rotating axis; in this process, one end of the lower connecting arm 4 of the safety rod rotates on the support 5, and the other end of the lower connecting arm 4 of the safety rod rotates on the rotating sleeve 402; one end of the upper connecting arm 1 of the safety rod rotates on the rotating sleeve 402, and the upper connecting arm 1 of the safety rod rotates on the center gasket 102.

[0062] S2 includes:

[0063] Locking stage: When the cab is flipped to the set angle, the locking device in the hydraulic system will automatically work to lock the piston of the hydraulic cylinder in the current position to prevent the cab from accidentally falling back due to external force or its own weight. The lower connecting arm 4 of the safety pull rod is connected to the limit pin 3 through the limit slot 407 to ensure that the cab remains in a stable flip state during maintenance or inspection.

[0064] S3 includes:

[0065] Reset stage: When the maintenance or inspection work is completed, rotate the flip rod on the hydraulic pump to the lowered position, and the driver operates the control device to issue a reset command to change the flow direction of the hydraulic oil, so that the hydraulic oil enters the rod chamber of the hydraulic cylinder, pushing the piston to retract; during the retraction of the piston, the cab slowly and steadily returns to its initial position under the combined action of gravity and the hydraulic system; during this process, one end of the lower connecting arm 4 of the safety rod rotates on the support 5, and the other end of the lower connecting arm 4 of the safety rod rotates on the rotating sleeve 402; one end of the upper connecting arm 1 of the safety rod rotates on the rotating sleeve 402, and the upper connecting arm 1 of the safety rod rotates on the center gasket 102; when the cab is completely reset, the pressure in the hydraulic system gradually decreases, and each component returns to its initial state, waiting for the next flip command.

[0066] One end of the lower connecting arm 4 of the safety rod rotates on the support 5, and the other end of the lower connecting arm 4 of the safety rod rotates on the rotating sleeve 402; one end of the upper connecting arm 1 of the safety rod rotates on the rotating sleeve 402, and the upper connecting arm 1 of the safety rod rotates on the center gasket 102.

[0067] The specific workflow of the present invention is as follows:

[0068] S1: Start the hydraulic cylinder; the piston rod of the hydraulic cylinder extends, pushing the cab to slowly flip upward around the rotating shaft; the upper connecting arm 1 of the safety lever and the lower connecting arm 4 of the safety lever rotate;

[0069] S2: When the cab is flipped to the set angle, the lower connecting arm 4 of the safety rod is connected to the limit pin 3 through the limit slot 407;

[0070] S3: When the maintenance or inspection work is completed, the piston rod of the hydraulic cylinder retracts, and the cab slowly and steadily returns to its initial position under the combined action of gravity and the piston rod; the upper connecting arm 1 of the safety rod and the lower connecting arm 4 of the safety rod rotate; the limit pin 3 is removed from the limit slot 407; the upper connecting arm 1 of the safety rod and the lower connecting arm 4 of the safety rod are reset.

[0071] The present invention has been described above with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described method. Any non-substantial improvements made using the method concepts and technical solutions of the present invention, or any direct application of the above-described concepts and technical solutions to other situations without modification, fall within the scope of protection of the present invention.

Claims

1. A cab front suspension safety limit mechanism, characterized by: The invention comprises an upper connecting arm (1) of a safety pull rod; one end of the upper connecting arm (1) of the safety pull rod is connected to a connecting bolt (2); the other end of the upper connecting arm (1) of the safety pull rod is connected to a limit pin (3) and a lower connecting arm (4) of the safety pull rod; the lower connecting arm (4) of the safety pull rod is engaged with the limit pin (3), and the lower connecting arm (4) of the safety pull rod is connected to a support (5); the support (5) is connected to a vehicle frame; the connecting bolt (2) is connected to an upper support (6) of a front suspension of a vehicle; the upper connecting arm (1) of the safety pull rod comprises a corrugated section (101).

2. A cab front suspension safety limit mechanism according to claim 1, characterized in that: The safety pull rod upper connecting arm (1) comprises a first upper connecting arm (7) and a second upper connecting arm (701); the connecting bolt (2) is connected to the first upper connecting arm (7) and the second upper connecting arm (701); the limiting pin (3) and the safety pull rod lower connecting arm (4) are arranged between the first upper connecting arm (7) and the second upper connecting arm (701).

3. A cab front suspension safety limit mechanism according to claim 2, characterized in that: A center gasket (102) is provided between the first upper connecting arm (7) and the second upper connecting arm (701); the first upper connecting arm (7) and the second upper connecting arm (701) are provided on the center gasket (102); an upper limit sleeve (702) is provided on the side of the first upper connecting arm (7) and the second upper connecting arm (701) away from the center gasket (102); a first flat washer (103) is provided between the upper limit sleeve (702) and the first upper connecting arm (7) and the second upper connecting arm (701); an upper mounting through hole (703) is provided on the first upper connecting arm (7) and the second upper connecting arm (701); the connecting bolt (2) is sleeved in the upper limit sleeve (702), the upper mounting through hole (703), the center gasket (102) and the first flat washer (103); the connecting bolt (2) is connected with a connecting nut (201).

4. A cab front suspension safety limit mechanism according to claim 3, characterized in that: The limit pin (3) is arranged on one end of the upper connecting arm (1) of the safety pull rod away from the connecting bolt (2); the first upper connecting arm (7) and the second upper connecting arm (701) are both provided with a limit pin mounting hole (301); the end of the limit pin (3) is arranged in the limit pin mounting hole (301); the end of the limit pin (3) is connected to a second flat washer (302), and the limit pin (3) is connected to a cotter pin (303).

5. A cab front suspension safety limit mechanism according to claim 4, characterized in that: The first upper connecting arm (7) and the second upper connecting arm (701) are both provided with a rotating sleeve mounting hole (401); the rotating sleeve mounting hole (401) is provided on one side of the limit pin mounting hole (301); a rotating sleeve (402) is provided in the rotating sleeve mounting hole (401); a first rotating hole (403) is provided at the end of the safety pull rod lower connecting arm (4); the rotating sleeve (402) is provided in the first rotating hole (403); the rotating sleeve (402) is connected with a fixing bolt (404); a third flat washer (405) is provided between the fixing bolt (404) and the first upper connecting arm (7); and the fixing bolt (404) is connected with a fixing nut (406).

6. A cab front suspension safety limit mechanism according to claim 5, characterized in that: The end of the lower connecting arm (4) of the safety pull rod is provided with a limiting slot (407); the limiting pin (3) is provided with a clamping section (304); and the clamping section (304) is arranged in the limiting slot (407).

7. A cab front suspension safety limit mechanism according to any one of claims 5-6, characterized in that: The support (5) includes a support side plate (501); a support sleeve mounting hole (502) is provided on the support side plate (501); a support sleeve (503) is provided in the support sleeve mounting hole (502); a second rotation hole (408) is provided at one end of the safety pull rod lower connecting arm (4) away from the first rotation hole (403); the safety pull rod lower connecting arm (4) is arranged between adjacent support side plates (501); the support sleeve (503) is arranged in the second rotation hole (408); a bolt (504) is connected to the support sleeve (503); a fourth flat washer (505) is provided between the bolt (504) and the support side plate (501); and a nut (506) is connected to the bolt (504).

8. A cab front suspension safety limit mechanism according to claim 7, characterized in that: The automobile front suspension upper support (6) comprises a first side plate (601) and a second side plate (602); the first side plate (601) is arranged between the upper limit sleeve (702) and the connecting bolt (2); the second side plate (602) is arranged between the upper limit sleeve (702) and the connecting nut (201); the first side plate (601) and the second side plate (602) are both provided with bolt holes (603); the connecting bolts (2) are connected in the bolt holes (603).

9. A method for using the cab front suspension safety limit mechanism according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: Start the hydraulic cylinder; the piston rod of the hydraulic cylinder extends, pushing the cab to slowly flip upward around the rotation axis; the upper connecting arm (1) of the safety lever and the lower connecting arm (4) of the safety lever rotate; S2: When the cab is flipped to a set angle, the lower connecting arm (4) of the safety pull rod is clamped onto the limiting pin (3) through the limiting clamping groove (407); S3: When the maintenance or inspection work is completed, the piston rod of the hydraulic cylinder retracts, and the cab slowly and steadily returns to the initial position under the combined action of gravity and the piston rod; the upper connecting arm (1) of the safety pull rod and the lower connecting arm (4) of the safety pull rod rotate; the limit pin (3) is removed from the limit slot (407); the upper connecting arm (1) of the safety pull rod and the lower connecting arm (4) of the safety pull rod are reset.

10. The method of use according to claim 9, characterized in that: One end of the lower connecting arm (4) of the safety pull rod rotates on the support (5), and the other end of the lower connecting arm (4) of the safety pull rod rotates on the rotating sleeve (402); one end of the upper connecting arm (1) of the safety pull rod rotates on the rotating sleeve (402), and the upper connecting arm (1) of the safety pull rod rotates on the central gasket (102).

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