A rear axle housing folding maintenance ladder and mine car
By designing a foldable rear axle housing maintenance ladder, the instability and wear problems of existing maintenance ladders within the rear axle housing were solved, improving operational safety and extending the service life of the rear axle housing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XUZHOU XCMG MINING MACHINERY CO LTD
- Filing Date
- 2025-06-11
- Publication Date
- 2026-05-26
AI Technical Summary
The existing maintenance ladder design has problems such as the risk of pinching hands, shaking and abnormal noise, safety hazards, and wear and tear on the rear axle door passage, and cannot effectively solve the maintenance problem of the rear axle housing.
A rear axle housing folding maintenance ladder was designed, including an upper maintenance ladder and a lower maintenance ladder. The ladder can be flipped and fixed through hinge points and fastening components to ensure the stability and safety of the ladder inside the rear axle housing.
This solution addresses the instability and wear issues of the maintenance ladder within the rear axle housing, improves operational safety, prevents contact between the ladder and the rear axle door passage, and extends the service life of the rear axle housing.
Smart Images
Figure CN224282489U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a folding maintenance ladder for the rear axle housing, belonging to the field of mining machinery. Background Technology
[0002] The power system of heavy-duty mining trucks achieves high torque output through rear axle drive. The rear axle housing, as a key component of the drive axle, has flanges at both ends bolted to the reducer. It contains components such as electric wheels, high-voltage wiring harnesses, and hydraulic wiring harnesses, requiring regular maintenance and upkeep. Generally, if... Figure 1 As shown, the rear axle housing generally consists of a drum 1, a rear axle door 2, and internal reinforcing plates 3. The rear axle door 2 has a small opening and limited space, making it impossible to install a conventional ladder. Furthermore, due to the height limitation of the heavy-duty mine car chassis, the rear axle door 2 is quite high above the ground, posing a safety hazard for maintenance personnel to climb directly. Using external ladders is inconvenient in the mining environment, and failure to retrieve them promptly poses an accident risk. Few other mine cars are equipped with maintenance ladders, and ordinary maintenance ladders are incompletely designed and have limited functionality. During vehicle operation, the maintenance ladder is not securely fixed, causing shaking and abnormal noise, and also potentially damaging the paint.
[0003] The existing patent discloses a rear axle housing assembly for an electric wheel dump truck (CN204263849U), which has the following shortcomings:
[0004] (a) The maintenance ladder is designed with two sets of hinge points, and the structure of the upper maintenance ladder is straight. The two sets of hinge points have the following problems:
[0005] 1. The tilting trajectory of the maintenance ladder is not fixed. During operation, it is impossible to control which hinge point 1 or hinge point 2 rotates first, which poses a risk of pinching hands during operation.
[0006] 2. When the maintenance ladder is inside the rear axle housing, its final retraction state is uncontrollable, causing shaking and abnormal noise during vehicle operation.
[0007] 3. When the maintenance ladder flips out of the rear axle housing, and the maintenance personnel step on the foot pedal forcefully, the maintenance ladder at the two sets of hinge points will move horizontally from side to side, posing a safety hazard.
[0008] (ii) The maintenance ladder is not fixed inside the rear axle housing when it is retracted. When the vehicle is running bumpy or accelerating or decelerating, the ladder will shake, flip, and hit the inside of the rear axle housing, which poses a safety hazard and damages the paint.
[0009] (iii) The maintenance ladder flips out of the rear axle housing, and the maintenance ladder directly presses on the inner wall of the rear axle door passage. The rear axle maintenance ladder is subjected to force and slippage for a long time, which damages the inner wall of the rear axle door passage. Rust will exist for a long time, affecting the life of the rear axle housing. Summary of the Invention
[0010] To address the shortcomings of existing technologies, this utility model provides a rear axle housing folding maintenance ladder, which has the advantages of ingenious design, simple structure, strong applicability, and durability.
[0011] This utility model is achieved according to the following technical solution:
[0012] In a first aspect, this utility model provides a folding maintenance ladder for the rear axle housing, comprising:
[0013] Two opposing maintenance ladder mounting brackets are connected to the inner wall of the drum near the rear axle door;
[0014] The maintenance ladder has its top two ends hinged to the corresponding maintenance ladder mounting bases, and the maintenance ladder can rotate around the hinge points.
[0015] The lower maintenance ladder is hinged at the top to the bottom of the upper maintenance ladder. The lower maintenance ladder can rotate around the hinge point. After rotating upwards, the lower maintenance ladder fits against the upper maintenance body and continues to rotate upwards to allow the upper and lower maintenance ladders to pass through the rear bridge door and enter the drum together.
[0016] The first fastening component is configured to secure and release the connection between the fitted lower access ladder and the upper access body;
[0017] The second fastening component is configured to secure and release the maintenance ladder located inside the drum from the maintenance ladder mounting base.
[0018] In some embodiments, the first fastening member is a pin holder, which includes:
[0019] A limiting pin round tube is fixed on the upper maintenance ladder near the maintenance ladder fixed mounting base;
[0020] The base is fixed on the maintenance ladder mounting seat, and the base has a round hole; after the maintenance ladder flips and contacts the rib plate inside the drum to limit its rotation, the limiting pin tube is located above the base and is coaxial with the round hole.
[0021] A limiting pin is inserted into the round tube and round hole of the limiting pin to fix the maintenance ladder in the drum.
[0022] In some embodiments, a chain connects the limiting pin to the base; and / or,
[0023] The base is provided with an elongated hole, which is used to connect to the maintenance ladder mounting base with bolts.
[0024] In some embodiments, the maintenance ladder mounting base includes:
[0025] The base plate has multiple mounting holes, which are connected to the threaded seat inside the drum with bolts.
[0026] The hinged seat mainly consists of two opposing ear plates. Each ear plate has a coaxial hinge hole I in its upper area. The flat top of the maintenance ladder with hinge hole II is inserted into the two ear plates. After the hinge hole II is coaxial with the hinge holes I on both sides, the hinged seat and the maintenance ladder are connected to form a rotating pair by a hinge component consisting of a fixing pin, a cotter pin, or a bolt and nut.
[0027] In some embodiments, the hinge seat extends outward from the side located below the hinge hole I and facing the rear axle door, the support frame limiting and supporting the maintenance ladder that flips out from the drum, so that the maintenance ladder does not come into contact with the rear axle door.
[0028] In some embodiments, each of the bottom ends of the upper maintenance ladder is fixed with an outwardly extending and opposite ear plate. The hinge holes at the top ends of the lower maintenance ladder are coaxial with the hinge holes on the corresponding ear plates. The lower maintenance ladder and the upper maintenance ladder are then connected to form a rotating pair by a hinge component consisting of a fixing pin, a cotter pin, or a bolt and nut.
[0029] In some embodiments, the second fastening component includes:
[0030] Ear plate, fixed at the overlapping part of the upper maintenance ladder and the folded lower maintenance ladder, the ear plate is provided with lock hole I, and the lower maintenance ladder is provided with lock hole II coaxial with lock hole I;
[0031] A fixing pin is inserted into the lock hole I and lock hole II to fix the lower maintenance ladder and the upper maintenance ladder together.
[0032] A chain connects the lugs to the retaining pin.
[0033] In some embodiments, both the upper and lower maintenance ladders include two opposing longitudinal beams and at least one tread located between the two longitudinal beams; the upper part of the longitudinal beams of the upper maintenance ladder is provided with a hook-shaped structure, the lower maintenance ladder is located in front of the upper maintenance ladder, and the bottom of the longitudinal beam of the upper maintenance ladder and the top of the longitudinal beam of the lower maintenance ladder have an overlapping area, and the lower maintenance ladder, after being flipped downwards, contacts the upper maintenance ladder and limits the lower maintenance ladder.
[0034] In some embodiments, the top surface of the pedal has a threaded hole at each end along its length, and the anti-slip plate is fixed to the pedal by screws engaging with the threaded holes: and / or,
[0035] Handles are fixed on any one or both longitudinal beams of the maintenance ladder to facilitate the turning of the ladder.
[0036] Secondly, this utility model provides a mining car, including a rear axle housing, on which the aforementioned rear axle housing folding maintenance ladder is installed.
[0037] The beneficial effects of this utility model are:
[0038] 1. The existing rear axle housing has a small rear axle door opening and limited structural space, making it impossible to equip it with a suitable maintenance ladder. By designing a foldable and flip-up maintenance ladder, the problem of maintenance personnel being unable to conveniently enter the confined space of the rear axle housing can be solved.
[0039] 2. The maintenance ladder is retracted into the rear axle housing. Through structural design, the rear axle housing maintenance ladder can be firmly fixed, solving the problems of the rear axle housing maintenance ladder tipping over, making abnormal noises and impacts while the vehicle is running.
[0040] 3. The rear axle housing maintenance ladder extends out of the rear axle door. Through structural design, the rear axle housing maintenance ladder does not come into contact with the rear axle door passage, thus solving the problem of rust caused by wear on the paint surface of the rear axle door.
[0041] 4. By adding an anti-slip plate design to the steps of the rear axle housing maintenance ladder, the problem of safety accidents caused by slipping on external ladders is solved.
[0042] 5. The maintenance ladder has only one set of hinge points. When the maintenance ladder is flipped, the trajectory of the maintenance ladder is fixed and predictable, ensuring the safety of personnel operation. Whether the rear axle housing is retracted or extended, its usage is relatively stable. Attached Figure Description
[0043] The accompanying drawings, as part of this utility model, are used to provide a further understanding of the present utility model. The illustrative embodiments and descriptions of the present utility model are used to explain the present utility model, but do not constitute an undue limitation of the present utility model. Obviously, the drawings described below are merely some embodiments; those skilled in the art can obtain other drawings based on these drawings without any creative effort.
[0044] In the attached diagram:
[0045] Figure 1 This is a diagram of the rear axle housing structure in the prior art;
[0046] Figure 2 This utility model provides a structural diagram of a folding maintenance ladder installed on the rear axle housing.
[0047] Figure 3 This is a diagram showing the usage status of the rear axle housing folding maintenance ladder of this utility model.
[0048] Figure 4 This is a structural diagram of the maintenance ladder of this utility model;
[0049] Figure 5This is a diagram showing the state of the inside of the rear axle housing of the maintenance ladder of this utility model when it is retracted.
[0050] Figure 6 This is a diagram showing the state of the maintenance ladder of this utility model when the rear axle housing is flipped out.
[0051] Figure 7 This is a structural diagram of the maintenance ladder mounting base of this utility model;
[0052] Figure 8 This is a structural diagram of the first fastening component of this utility model.
[0053] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the present invention in any way, but rather to illustrate the concept of the present invention to those skilled in the art by referring to specific embodiments. Detailed Implementation
[0054] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate this utility model, but are not intended to limit the scope of this utility model.
[0055] In the description of this utility model, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0056] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0057] like Figure 2 As shown, the maintenance ladder 4 passes through the rear axle door 2 and is fixed inside the drum 1. The internal stiffener 3 of the rear axle housing is used to strengthen the structural strength of the rear axle housing. When the maintenance ladder 4 is flipped into the rear axle housing, it can limit the movement of the maintenance ladder 4.
[0058] The following provides a further explanation of the specific structure of the aforementioned maintenance ladder.
[0059] like Figure 3As shown, a rear axle housing folding maintenance ladder includes a fixing pin 4.1, a pin seat 4.2, a washer 4.3, a cotter pin 4.4, an upper maintenance ladder 4.5, a screw 4.6, a washer 4.7, an anti-slip plate 4.8, a lower maintenance ladder 4.9, and a maintenance ladder mounting base 4.10. The anti-slip plate 4.8 is fixed to the upper maintenance ladder 4.5 and the lower maintenance ladder 4.9 respectively by screws 4.6 and washers 4.7. The lower maintenance ladder 4.9 is connected by two sets of fixing pins 4.1, washers 4.3, and cotter pins 4.4. The upper maintenance ladder 4.5 is connected to the maintenance ladder mounting base 4.10 by fixing pins 4.1, washers 4.3, and cotter pins 4.4, forming a rotating pair. The maintenance ladder mounting base 4.10 is connected inside the rear axle housing drum. When the maintenance ladder 4 is not in operation, the lower maintenance ladder 4.9 flips over and approaches the upper maintenance ladder 4.5. The upper maintenance ladder 4.5 and the lower maintenance ladder 4.9 then flip together and enter the drum 1, where they are securely fixed. This maintenance ladder 4 allows maintenance personnel easy access to the rear axle housing. After maintenance is completed, it is retracted into the rear axle housing. This structure is simple, reliable, and improves overall safety performance.
[0060] The following provides a further explanation of the specific structure of the aforementioned maintenance ladder.
[0061] like Figure 4 As shown, two footboards 4.5.3 are welded at appropriate positions between the two longitudinal beams 4.5.2 of the upper maintenance ladder for maintenance personnel to climb. The footboards 4.5.3 have openings for securing the anti-slip plate 4.8. Handles 4.5.7 are welded at appropriate positions on the longitudinal beams 4.5.2 of the upper maintenance ladder, facilitating the pull-out of the ladder from the rear axle housing by maintenance personnel. The upper maintenance ladder also has three lugs 4.5.4 welded on. The two lower lugs 4.5.4 are used to connect to the lower maintenance ladder. The upper lug 4.5.4 provides a fixing point for the lower maintenance ladder to flip and approach the upper maintenance ladder. A chain 4.5.6 is welded to the upper lug 4.5.4, and a fixing pin 4.5.5 is welded to the end of the chain 4.5.6 for limiting the lower maintenance ladder's position when it flips and engages with the upper maintenance ladder. A limiting pin tube 4.5.1 is also welded to the longitudinal beams 4.5.2 of the upper maintenance ladder for limiting the overall movement of the ladder.
[0062] It should be noted that, as Figure 3 As shown, the lower maintenance ladder 4.9 includes two longitudinal beams and a step located between the two longitudinal beams. The step has openings for fixing the anti-slip plate 4.8. The lower maintenance ladder 4.9 is located in front of the upper maintenance ladder 4.5, and the bottom of the longitudinal beam of the upper maintenance ladder 4.5 overlaps with the top of the longitudinal beam of the lower maintenance ladder 4.9. After the lower maintenance ladder 4.9 is flipped downwards, it contacts the upper maintenance ladder 4.5 and limits the lower maintenance ladder 4.9.
[0063] like Figure 5As shown, this is the state of the maintenance ladder when it is retracted into the rear axle housing. The lower maintenance ladder 4.9 rotates and fits against the upper maintenance ladder 4.5, and is fixed by the fixing pin 4.1 and the cotter pin 4.4. After the entire maintenance ladder is retracted into the rear axle housing, the upper maintenance ladder 4.5 contacts the internal stiffening plate 3 of the rear axle housing, and the entire maintenance ladder achieves a stable state of multi-point contact.
[0064] like Figure 5 , Figure 8 As shown, the pin seat 4.2 is fixed on the maintenance ladder mounting base 4.10, including a limiting pin 4.2.1, a chain 4.2.2, and a base 4.2.3. When the maintenance ladder is retracted into the rear axle housing, it reaches its final state. The position of the limiting pin tube 4.5.1 on the upper maintenance ladder 4.5 is determined. The base 4.2.3 has a round hole. By adjusting the elongated hole on the base 4.2.3, the round hole on the base 4.2.3 is made coaxial with the limiting pin tube 4.5.1 on the upper maintenance ladder 4.5. The limiting pin 4.2.1 passes through the limiting pin tube 4.5.1 and the round hole on the base 4.2.3, thus limiting the maintenance ladder and preventing it from tipping over during mine car operation.
[0065] When using the rear axle housing maintenance ladder, the maintenance personnel stand on the ground, first pull out the limit pin 4.2.1, reach into the rear axle housing, grasp the handle 4.5.7, remove the entire maintenance ladder, pull out the fixing pin 4.1 and cotter pin 4.4, lower the lower maintenance ladder 4.9, and the maintenance ladder can be used. After use, flip the lower maintenance ladder 4.9 upwards, close it to the upper maintenance ladder 4.5, and fix it with the fixing pin 4.1 and cotter pin 4.4. Then flip the entire maintenance ladder into the rear axle housing, and finally use the limit pin 4.2.1 to limit it.
[0066] The following provides a further explanation of the specific structure of the aforementioned maintenance ladder mounting base.
[0067] like Figure 7 As shown, the maintenance ladder mounting base includes a base plate and a hinged base. The base plate has multiple mounting holes, which are bolted to threaded seats inside the drum. The hinged base mainly consists of two opposing ear plates. Each ear plate has a coaxial hinge hole I in its upper area. The flat top of the maintenance ladder with hinge holes II is inserted into the two ear plates. After hinge holes II are coaxial with the hinge holes I on both sides, the hinged base and the maintenance ladder are connected to form a rotating pair by fixing pins and cotter pins. A support frame extends outward from the side of the hinged base located below hinge holes I and facing the rear axle door.
[0068] like Figure 6As shown, after the maintenance ladder is flipped out, the longitudinal beams 4.5.2 on both sides of the upper maintenance ladder 4.5 come into contact with the support frame 4.10.1 extending from the fixed mounting base 4.10 of the maintenance ladder. The support frame 4.10.1 mainly bears the force of the maintenance ladder. At this time, there is a gap between the upper maintenance ladder 4.5 and the rear axle door 2, which avoids the maintenance ladder from damaging the paint surface of the rear axle door passage and causing corrosion problems. This achieves the effect of protecting the paint surface and extending the service life of the entire rear axle housing.
[0069] In summary, this utility model provides a folding maintenance ladder for the rear axle housing, achieving the following functions and effects:
[0070] 1. The existing rear axle housing has a small rear axle door opening and limited structural space, making it impossible to equip it with a suitable maintenance ladder. By designing a foldable and flip-up maintenance ladder, the problem of maintenance personnel being unable to conveniently enter the confined space of the rear axle housing can be solved.
[0071] 2. The maintenance ladder is retracted into the rear axle housing. Through structural design, the rear axle housing maintenance ladder can be firmly fixed, solving the problems of the rear axle housing maintenance ladder tipping over, making abnormal noises and impacts while the vehicle is running.
[0072] 3. The rear axle housing maintenance ladder extends out of the rear axle door. Through structural design, the rear axle housing maintenance ladder does not come into contact with the rear axle door passage, thus solving the problem of rust caused by wear on the paint surface of the rear axle door.
[0073] 4. By adding an anti-slip plate design to the steps of the rear axle housing maintenance ladder, the problem of safety accidents caused by slipping on external ladders is solved.
[0074] 5. The maintenance ladder has only one set of hinge points. When the maintenance ladder is flipped, the trajectory of the maintenance ladder is fixed and predictable, ensuring the safety of personnel operation. Whether the rear axle housing is retracted or extended, its usage is relatively stable.
[0075] The following describes the mine car provided by this utility model. The mine car described below can be referred to in correspondence with the maintenance ladder described above.
[0076] The present invention provides a mining car that may include a maintenance ladder as described in any of the above embodiments.
[0077] The beneficial effects achieved by the mining car provided by this utility model are consistent with the beneficial effects achieved by the maintenance ladder provided by this utility model, so they will not be repeated here.
[0078] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.
[0079] Furthermore, those skilled in the art will understand that although some embodiments described herein include certain features found in other embodiments but not others, combinations of features from different embodiments are also within the scope of protection of this invention and form different embodiments. For example, in the embodiments described above, those skilled in the art can use them in combination based on known technical solutions and the technical problems to be solved by this application.
[0080] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.
Claims
1. A rear axle housing fold-down service ladder characterized by, include: Two opposing maintenance ladder mounting brackets are connected to the inner wall of the drum near the rear axle door; The maintenance ladder has its top two ends hinged to the corresponding maintenance ladder mounting bases, and the maintenance ladder can rotate around the hinge points. The lower maintenance ladder is hinged at the top to the bottom of the upper maintenance ladder. The lower maintenance ladder can rotate around the hinge point. After rotating upwards, the lower maintenance ladder fits against the upper maintenance body and continues to rotate upwards to allow the upper and lower maintenance ladders to pass through the rear bridge door and enter the drum together. The first fastening component is configured to secure and release the connection between the fitted lower access ladder and the upper access body; The second fastening component is configured to secure and release the maintenance ladder located inside the drum from the maintenance ladder mounting base.
2. A folding service ladder for a rear axle housing as defined in claim 1, wherein, The first fastening component is a pin holder, which includes: A limiting pin round tube is fixed on the upper maintenance ladder near the maintenance ladder fixed mounting base; The base is fixed on the maintenance ladder mounting seat, and the base has a round hole; after the maintenance ladder flips and contacts the rib plate inside the drum to limit its rotation, the limiting pin tube is located above the base and is coaxial with the round hole. A limiting pin is inserted into the round tube and round hole of the limiting pin to fix the maintenance ladder in the drum.
3. The rear axle housing folding maintenance ladder according to claim 2, characterized in that: A chain connects the limiting pin to the base; and / or, The base is provided with an elongated hole, which is used to connect to the maintenance ladder mounting base with bolts.
4. The folding service ladder for a rear axle housing of claim 1 wherein, The maintenance ladder mounting base includes: The base plate has multiple mounting holes, which are connected to the threaded seat inside the drum with bolts. The hinged seat mainly consists of two opposing ear plates. Each ear plate has a coaxial hinge hole I in its upper area. The flat top of the maintenance ladder with hinge hole II is inserted into the two ear plates. After the hinge hole II is coaxial with the hinge holes I on both sides, the hinged seat and the maintenance ladder are connected to form a rotating pair by a hinge component consisting of a fixing pin, a cotter pin, or a bolt and nut.
5. A rear axle housing folding maintenance ladder according to claim 4, characterized in that: The hinge seat extends outward from the side located below the hinge hole I and facing the rear axle door, and the support frame limits and supports the maintenance ladder that flips out from the drum, so that the maintenance ladder does not come into contact with the rear axle door.
6. A rear axle housing folding maintenance ladder according to claim 1, characterized in that: The bottom ends of the upper maintenance ladder are each fixed with an outwardly extending and opposite ear plate. The hinge holes at the top ends of the lower maintenance ladder are coaxial with the hinge holes on the corresponding ear plates. The lower maintenance ladder and the upper maintenance ladder are connected to form a rotating pair by a hinge component consisting of a fixing pin, a cotter pin, or bolts and nuts.
7. A rear axle housing folding maintenance ladder according to claim 1, characterized in that, The second fastening component includes: Ear plate, fixed at the overlapping part of the upper maintenance ladder and the folded lower maintenance ladder, the ear plate is provided with lock hole I, and the lower maintenance ladder is provided with lock hole II coaxial with lock hole I; A fixing pin is inserted into the lock hole I and lock hole II to fix the lower maintenance ladder and the upper maintenance ladder together. A chain connects the lugs to the retaining pin.
8. A rear axle housing folding maintenance ladder according to claim 1, characterized in that: Both the maintenance ladder and the maintenance descending ladder include two opposing longitudinal beams and at least one tread located between the two longitudinal beams; The upper part of the longitudinal beam of the upper maintenance ladder is designed with a hook-shaped structure. The lower maintenance ladder is located in front of the upper maintenance ladder, and the bottom of the longitudinal beam of the upper maintenance ladder and the top of the longitudinal beam of the lower maintenance ladder overlap. After the lower maintenance ladder is flipped downwards, it contacts the upper maintenance ladder and limits the lower maintenance ladder.
9. A rear axle housing folding maintenance ladder according to claim 8, characterized in that: The top surface of the pedal has a threaded hole at each end along its length, and the anti-slip plate is fixed to the pedal by screws engaging with the threaded holes: and / or, Handles are fixed on any one or both longitudinal beams of the maintenance ladder to facilitate the turning of the ladder.
10. A mining car, comprising a rear axle housing, characterized in that: The rear axle housing is equipped with a folding maintenance ladder as described in any one of claims 1 to 9.