A rotary stairway device for a combine harvester cab walkway

Abstract

The application discloses a rotating ladder device for a driver's cabin walkway of a combine harvester, which comprises a base and a rotating ladder. The rotating ladder is rotatably installed on the base. The rotating ladder is movable between a retracted position and at least one expanded position. The base is provided with a hinge joint. The rotating ladder is provided with a supporting hinge element matched with the hinge joint. At least two locking holes are arranged on the side of the hinge joint facing the rotating ladder. The two locking holes correspond to the retracted position and the expanded position of the rotating ladder respectively. The device meets the safety requirement of the driver's cabin ladder during the road driving of the combine harvester. The operator can reliably and effectively store the ladder on the ground and on the driver's cabin platform. During the harvesting operation, the ladder will not become the outermost end of the combine harvester to cause the contact with the left plants, so that the farmers can avoid the loss.

Description

Technical Field

[0001] This invention belongs to the field of harvesters and relates to a rotating ladder device for the cab walkway of a combine harvester. Background Technology

[0002] A ladder is a ladder installed to facilitate the operator's access to the workspace. Currently, the vertical height of the combine harvester cab from the ground is generally greater than 550mm, and according to national standards, a ladder should be installed in all of them. When the combine harvester is moved along the road, the ladder becomes the outermost part of the machine, which can lead to collisions with other vehicles while traveling on the road, and the ladder knocking over unharvested crops while harvesting.

[0003] The ladders used in existing combine harvester cabs are generally fixed to the cab walkway, with a structure that gradually slopes outwards from top to bottom, exposed on the outside of the machine. When combine harvesters are moved from road to road, the exposed ladders not only make the combine harvester's width exceed the standard, but also cause it to repeatedly collide with the plants on the side of the combine harvester during harvesting, resulting in damage to both the combine harvester and the harvested plants, causing losses to both the harvester owner and the farmer. Although there are mechanisms in existing technology to rotate the ladders, they are not convenient to operate. Summary of the Invention

[0004] The purpose of this invention is to solve the problems existing in the prior art and provide a rotating ladder device for the cab walkway of a combine harvester. This device meets the safety requirements of the cab ladder when the combine harvester is traveling on the road. The operator can reliably and effectively store the ladder from both the ground and the cab platform. Moreover, during harvesting operations, the ladder will not be at the outermost edge of the machine and will not come into contact with the plants on the left, thus avoiding losses for farmers.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a rotating ladder device for a combine harvester cab walkway, comprising a base and a rotating ladder, the rotating ladder being rotatably mounted on the base, the rotating ladder being movable between a retracted position and at least one extended position, a hinge joint being provided on the base, a supporting hinge member cooperating with the hinge joint being provided on the rotating ladder, and at least two locking holes being provided on the side of the hinge joint; the locking holes are used to lock the rotating ladder in the retracted position or the extended position respectively.

[0006] As a preferred embodiment, the rotating ladder is provided with a locking mechanism that mates with the lock hole; the locking mechanism includes a lock head adapted to the shape of the lock hole and a pull rod assembly. The lock head extends into the corresponding lock hole to lock the rotating ladder in the corresponding retracted or extended position. One end of the lock head is hinged to the pull rod assembly. Under the action of the pull rod assembly, the lock head can be pulled out of the lock hole to unlock, so that the rotating ladder and the base are in a state of relative rotation.

[0007] As a preferred embodiment, the system also includes a lock head sleeve, which is fixed to the hinged end of the rotating ladder and has a sliding hole for the lock head to move in the telescopic direction.

[0008] As a preferred embodiment, the pull rod assembly further includes a pull plate and a pull handle. The first end of the pull plate is hinged to the lock head, the second end of the pull plate is hinged to the pull handle, and the middle section of the pull plate is also connected to one end of a tension spring. The other end of the tension spring is fixed to the rotating ladder. Under the tension of the tension spring, the lock head can automatically reset and enter the corresponding lock hole in its natural state to lock the rotating vehicle body.

[0009] As a preferred embodiment, the middle hinge point of the pull handle is rotatably connected to the rotating ladder. The pull handle is divided into two sections through the middle hinge point. The first section of the pull handle is hinged to the pull rod, and the second section of the pull handle is hinged to the first end of the connecting rod. The second end of the connecting rod is hinged to the lower end of the control rod welded component. The control rod welded component is rotatably mounted on the rotating ladder and passes through the rotating ladder from bottom to top. A flower-shaped knob is provided at the upper end of the control rod welded component.

[0010] As a preferred embodiment, the control rod welded assembly includes a control rod body and a control rod connecting plate fixedly disposed at the lower end of the control rod body. The hinge point between the control rod connecting plate and the connecting rod can rotate about the control rod body as the axis.

[0011] As a preferred embodiment, the control lever connecting plate is provided with a limit arm. When the lock head is pulled out of the lock hole, the lock head, pull rod, handle, connecting rod, and control lever connecting plate are linked in sequence, thereby causing the limit arm to rotate and abut against the stop plate to limit the pull-out position of the lock head.

[0012] As a preferred embodiment, the rotating ladder is provided with a positioning pin, which is located on one side of the lock head. When the rotating ladder rotates to the retracted position, the positioning pin abuts against the side of the base, and the lock head can be just right to be engaged in the corresponding lock hole.

[0013] As a preferred embodiment, the two keyholes are arranged at a 90° angle.

[0014] As a preferred embodiment, the hinge joint is provided with a vertical shaft hole, and the outer side wall of the hinge joint is provided with a corresponding locking hole. The supporting hinge component includes an upper hinge component and a lower hinge component. The upper hinge component and the lower hinge component are vertically aligned and are provided with corresponding bushings. The bushings correspond to the vertical shaft hole, and the hinge shaft passes through the bushings and the vertical shaft hole in sequence to realize the rotatable connection between the hinge joint and the supporting hinge component.

[0015] Beneficial effects

[0016] Firstly, this solution, through improvements, provides an inventive concept different from existing technologies. It enables the combine harvester cab walkway ladder to be rotated 90° for safe storage, meeting the safety requirements of the cab walkway ladder while the combine harvester is traveling on roads. The operator can enter the cab by rotating the ladder, and can also adjust and fix the ladder from 0° to 90° on the cab platform and the ground, allowing for reliable and effective storage of the ladder. Moreover, during harvesting operations, the ladder will not be at the outermost edge of the machine, preventing it from colliding with the plants on the left side and avoiding losses for farmers.

[0017] Secondly, this solution incorporates an improved pull rod assembly, which includes a handle located below the rotating ladder and a flower-shaped knob located above the rotating body. This allows the rotation of the rotating ladder to be controlled from both the top and bottom, making the operation of the rotating ladder more convenient. When the ladder is rotated to the correct position, the tension of the pull rod assembly's spring automatically pushes the lock head into the corresponding lock hole, thus locking the rotating ladder. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 Installation diagram of the rotating staircase device (in use);

[0020] Figure 2 Schematic diagram of the normal retracted state of the rotating staircase device;

[0021] Figure 3 This is a disassembled schematic diagram of the connection between the rotating vehicle body and the base.

[0022] Figure 4 for Figure 2 Enlarged schematic diagram of the connection between the rotating vehicle body and the base;

[0023] Figure 5 Schematic diagram of the internal structure of the rotating staircase Figure 1 ;

[0024] Figure 6 Schematic diagram of the internal structure of the rotating staircase Figure 2 ;

[0025] Figure 7 This is a schematic diagram showing the installation of the locking mechanism inside the rotating staircase;

[0026] Figure 8 Cross-sectional view of the rotating staircase in locked state;

[0027] Figure 9 Cross-sectional view of the rotating staircase in the unlocked state;

[0028] The diagram is marked with the following components: 1. Walkway suspension; 2. Left walkway; 3. Hinge joint; 4. Support hinge; 5. Rotating staircase; 5.1. Staircase walkway; 5.1.1. Front reinforcing rib; 5.1.2. Walkway panel; 5.1.3. Shaft mounting plate; 5.1.4. Locating pin; 5.1.5. Spring hanging plate; 5.1.6. Bottom reinforcing rib of walkway; 5.1.7. Right reinforcing rib of walkway; 5.1.8. Walkway handle assembly bushing; 5.1.9. Walkway cross plate; 5.1.10. Right connecting plate; 5.1.11. Walkway inclined plate; 5.1.12. Left reinforcing rib of walkway; 5.1.13. Left connecting plate; 5.2. Right handrail welded assembly; 5. 3. Lock head; 5.4. Pin assembly II; 5.5. Fastening bolt I; 5.6. Lock head sleeve; 5.7. Pull rod; 5.8. Tension spring; 5.9. Handle assembly bushing wear pad; 5.11. Pull handle; 5.12. Pin assembly I; 5.13. Connecting rod; 5.14. Control rod welded assembly; 5.14.1. Control rod connecting plate; 5.14.2. Control rod body; 5.14.3. Stop part; 5.15. Flower-shaped knob; 6. Pedal assembly; 7. Snap ring; 8. Hinge shaft; 9. Stop plate; 10. Bushing; 11. Fastening bolt II; 20. Cab. Detailed Implementation

[0029] The present invention will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0030] It should be noted that, unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," or "the," and similar words used in the specification and claims of this patent application do not express a limitation of quantity, but rather indicate the presence of at least one. Terms such as "comprising" or "including" indicate that the elements or objects preceding "comprising" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects having the same function.

[0031] As shown in the figure, this embodiment provides a rotating ladder device for a combine harvester cab walkway, including a base and a rotating ladder 5 rotatably mounted on the base. The rotating ladder 5 is movable between a retracted position and at least one extended position. In the retracted position, the rotating ladder 5 rotates inward from its extended state on the outside of the machine to prevent it from exceeding the width of the harvester. In the extended position, the rotating ladder rotates outward from the retracted position to allow the operator to easily enter the cab 20 through the door. In the corresponding retracted and extended positions, the rotating ladder 5 can be fixed to the corresponding position on the base by a locking mechanism. It should be noted that in this text, "front" refers to the direction of machine movement, "left" refers to the driver's left side, and "right" refers to the driver's right side. (Appendix) Figure 1 The image shows the rotating platform device on the cab of a combine harvester in use. Figure 2 The diagram shows the rotating staircase device housed within the walkway suspension welded assembly 1.

[0032] In this design, the base includes a walkway suspension 1, a left walkway 2, and a hinge joint 3. The left walkway 2 is fixed to the walkway suspension 1 and can be fixed by welding or bolting. In this design, the hinge joint 3 is a hinge casting used to install the rotating ladder 5. The hinge joint 3 includes a hinge part and fixing ears on both sides of the hinge part. The two fixing ears can be fixed to the walkway suspension 1 by bolts. The hinge joint 3 is fixed to the walkway suspension 1 by fastening bolts II11. The hinge part is provided with a vertical shaft hole. A positioning groove 3.1 is provided on the outer ring side of the hinge part. The groove depth of the positioning groove 3.1 is set along the radial direction of the shaft hole. In this design, the retracted position and the extended position of the rotating ladder 5 are designed to be at a 90° angle. Therefore, in this design, the positioning groove 3.1 of the hinge part is arranged around the shaft hole at a 90° angle. Of course, it can also be set to other angles as needed.

[0033] In this embodiment, the rotating ladder 5 includes a ladder body and a supporting hinge 4 disposed on the hinge side of the ladder body. The supporting hinge 4 includes a supporting base, an upper hinge portion and a lower hinge portion integrally disposed on the supporting base. The upper hinge portion and the lower hinge portion are arranged vertically and are basically parallel. A bushing 10 is correspondingly disposed in the holes of the upper and lower hinge portions. The bushing 10 is fitted into the holes of the upper and lower hinge portions by an interference fit. The supporting hinge 4 and the bushing 10 are together fixed to the hinge side of the rotating ladder 5 by fastening bolt I5.5. A through hole is provided on the supporting base for the lock head 5.3 below the rotating ladder 5 to extend outward from the through hole and enter the corresponding positioning groove 3.1 to fix the rotating ladder 5.

[0034] In this design, after the rotating ladder 5 is connected to the base, the upper and lower hinge parts are located on the upper and lower sides of the hinge joint 3, respectively. The bushing 10 corresponds to the vertical shaft hole of the hinge joint 3. The hinge shaft 8 passes through the hinge joint 3 and the supporting hinge part 4, and is installed in the corresponding slot of the ladder hinge shaft 8 by the snap ring 7, thereby realizing the rotatable connection between the rotating ladder 5 and the hinge joint 3. Through this mechanism, the rotating ladder 5 can rotate around the hinge shaft 8. The front end and left side of the hinge joint 3 both have positioning grooves 3.1, the size of which matches the lock head 5.3, which can realize the positioning and locking of the rotating ladder 5 at 0° and 90° angles.

[0035] In this embodiment, the rotating ladder 5 includes a ladder platform 5.1, a ladder handrail 5.2, and a locking mechanism. The ladder handrail 5.2 is located on both sides of the ladder platform 5.1. The ladder platform 5.1 includes a front reinforcing rib 5.1.1, a platform panel 5.1.2, a shaft mounting plate 5.1.3, a positioning pin 5.1.4, a spring hanging plate 5.1.5, a bottom reinforcing rib 5.1.6, a right reinforcing rib 5.1.7, a handle assembly bushing 5.1.8, a platform cross plate 5.1.9, a right connecting plate 5.1.10, a platform inclined plate 5.1.11, a left reinforcing rib 5.1.12, and a left connecting plate 5.1.13. The front of the walkway panel 5.1.2 is welded to the shaft mounting plate 5.1.3. The left and right sides of the walkway panel 5.1.2 are welded to the left reinforcing rib 5.1.12 and the right reinforcing rib 5.1.7 respectively. The bottom is vertically welded with the walkway inclined plate 5.1.11 and the walkway horizontal plate 5.1.9, and the bottom reinforcing rib 5.1.6 is horizontally welded to form a rigid frame structure. The left connecting plate 5.1.13 and the right connecting plate 5.1.10 are welded to the left and right sides respectively to further strengthen the structure. At the same time, the assembly holes on the left / right connecting plates of the ladder can be used for the installation of the pedal assembly 6. The locking mechanism is located below the ladder walkway panel 5.1.2 of the ladder walkway 5.1.

[0036] In this scheme, the locking mechanism is used to position the rotating car body 5 and lock it in place at the corresponding positioning groove 3.1 of the hinge joint 3. One embodiment of the locking mechanism can adopt the following structure: The locking mechanism includes a lock head 5.3, a pin assembly II 5.4, a fastening bolt III 5.5, a lock head sleeve 5.6, a pull plate 5.7, a tension spring 5.8, a handle assembly bushing wear pad 5.9, a fastening bolt IV 5.10, a handle 5.11, a pin assembly I 5.12, a connecting rod 5.13, a car ladder control rod 5.14, and a flower-shaped knob 5.15. The lock head 5.3 includes a lock head seat and a sliding lock head mounted on the lock head seat. The outer diameter of the lock head seat is larger than the outer diameter of the sliding lock head, forming a limiting platform on the lock head 5.3. The lock head sleeve 5.6 includes a sleeve base and fixing ears on both sides of the sleeve base. The fixing ears are fixed to the stair platform 5.1 by fastening bolts III 5.5. The sleeve base is provided with a transverse sliding hole for installing the lock head 5.3. The sliding lock head slides into the transverse sliding hole from one end and extends outwards and rotates. The ladder 5 allows it to engage with the positioning groove 3.1 of the hinge joint 3. To facilitate the engagement of the lock head 5.3, the engaging end of the sliding lock head has a flat head structure or a frustum-shaped structure. When it is a flat head structure, it has beveled surfaces on both sides, resulting in a progressively increasing cross-sectional width from the end to the end. When it is a frustum-shaped structure, its outer diameter progressively increases from the end to the end, making it easier for the lock head 5.3 to enter the corresponding positioning groove 3.1 and reducing the accuracy requirements for alignment. When the lock head 5.3 extends into the corresponding positioning groove 3.1, its extension position is limited by the lock head limiting platform.

[0037] In this embodiment, the tail of the lock head 5.3 is hinged to the first end of the pull plate 5.7 via a pin assembly II 5.4. Under the pulling force of the pull plate 5.7, the lock head 5.3 can be pulled out from the positioning groove 3.1. The other end of the pull plate 5.7 is connected to the rod of the handle 5.11. The rod of the handle 5.11 has three mounting holes. One end of the walkway handle assembly bushing 5.1.8 is fixed to the walkway panel 5.1.2. The fastening bolt IV 5.10 passes through the middle mounting hole of the handle 5.11 and the wear-resistant pad 5.9 of the handle assembly bushing, and is then fastened to the walkway handle assembly bushing. In the axially set internal threaded hole of sleeve 5.1.8, the wear-resistant pad 5.9 of the handle assembly bushing is located between the walkway handle assembly bushing 5.1.8 and the handle 5.11 to prevent relative wear between the two. The mounting hole located on the handle 5.11 rod body near the handle grip end is connected to the pull plate 5.7, while another mounting hole located on the handle 5.11 rod body away from the handle grip part is hinged to the first end of the connecting rod 5.13 through the pin assembly I 5.12. The other end of the connecting rod 5.13 is hinged to the lower end of the ladder control rod 5.14 through the pin assembly I 5.12.

[0038] In this design, to enable the lock head 5.3 to automatically engage with the positioning groove 3.1, a tension spring 5.8 is also provided. One end of the tension spring 5.8 is attached to the spring hanging plate 5.1.5 of the rotating stair platform 5.1, and the other end is attached to the small hole in the middle of the rotating pull plate 5.7. In this design, the direction of the tension force of the tension spring 5.8 forms an acute angle with the overall setting direction of the pull plate 5.7. The purpose is to ensure that the tension of the tension spring 5.8 has a component force in the direction of pushing the lock head 5.3 to engage with the positioning groove 3.1. Thus, when the lock head 5.3 corresponds with the positioning groove 3.1, the tension spring 5.8 can automatically pull the pull plate 5.7, thereby pushing the lock head 5.3 to slide out of the rotating stair platform 5 along the transverse sliding hole through the pull plate 5.7, and thus enter the positioning groove 3.1.

[0039] In this design, the elevator control lever 5.14 includes a control lever body 5.14.2 and a control lever connecting plate 5.14.1. The control lever body 5.14.2 is mounted on the rotating sleeve of the rotating elevator 5. A flower-shaped knob 5.15 is located at the upper end of the control lever body 5.14.2, and the lower end extends through the rotating sleeve and connects to the control lever connecting plate 5.14.1, thus enabling the elevator control lever 5.14 to be rotatably mounted on the rotating elevator 5. In this design, the control lever connecting plate 5.14.1 has an approximately L-shaped structure, including a first short arm and a second short arm. The connection between the first short arm and the second short arm is... A hinge hole is formed, and the control rod connecting plate 5.14.1 is connected to the other end of the connecting rod 5.13 through the hinge hole. The end of the first short arm is formed with a folded edge and welded to the lower end of the control rod body 5.14.2. The function of the second short arm is as a stop part 5.14.3. When the lock head 5.3 is pulled outward from the positioning groove 3.1, the lock head 5.3, pull plate 5.7, handle 5.11, connecting rod 5.13, and control rod connecting plate 5.14.1 are linked in sequence, so that the second short arm rotates and abuts against the stop plate 9 on one side of the rotating ladder 5 to limit the pull-out position of the lock head 5.3. The purpose of this design is twofold: firstly, the lock head 5.3 will not completely disengage from the lock head sleeve 5.6, while limiting the maximum extension of the tension spring 5.8 to prevent damage caused by exceeding the maximum extension; secondly, it ensures that the linkage between the upper and lower sides can be achieved whether the flower-shaped knob 5.15 is rotated or the handle 5.11 is pulled, thus reasonably optimizing and simplifying the equipment structure.

[0040] In this design, connecting rod 5.13 is a ball joint connecting rod assembly, which includes ball head one, ball head two, and an intermediate rod disposed between ball head one and ball head two. Both ball head one and ball head two are provided with bearings for rotatable connection. Rotatable connection between their two ends is achieved through bearings and pin assembly I 5.12. Both ball head one and ball head two are provided with internal threaded holes at their ends, and both ends of the intermediate rod are provided with external threaded heads that mate with the internal threaded holes. The length of connecting rod 5.13 can be adjusted by rotating the intermediate rod. At the same time, locking nuts are provided at the connection between the intermediate rod and ball head one and ball head two, which are used to lock and fix ball head one and ball head two after the length of connecting rod 5.13 is adjusted. The length adjustment of connecting rod 5.13 can be used to adjust the limit position of the lock head 5.3 pull-out, and can also facilitate the adjustment of the linkage of the locking mechanism after the components are assembled.

[0041] In this design, rotating the flower-shaped knob 5.15 in the mechanism drives the ladder control lever 5.14 to rotate, and the connecting rod 5.13 moves inward together to achieve the purpose of moving the handle 5.11 on the other side outward. The lock head 5.3 can be pulled out by the pull plate 5.7, and in conjunction with the tension spring 5.8 with the telescopic function, the telescopic function of the lock head 5.3 can be realized. Moving the handle 5.11 in direction A can also achieve this effect.

[0042] In this embodiment, as shown in the figure, the operator stands on the left platform 2 and rotates the flower-shaped knob 5.15, or stands on the ground and moves the handle 5.11, to disengage the lock head 5.3 from the positioning groove 3.1 of the hinge joint 3 and achieve the open state; at the same time, the rotating ladder 5 can be pushed to rotate 90° to the front end of the platform suspension 1. During this process, the operator subsequently releases the flower-shaped knob 5.15 or the handle 5.11, and the pull plate 5.7 is continuously pulled by the tension spring 5.8. When it reaches the front end of the platform suspension 1, under the action of the tension spring 5.8, the lock head 5.3 returns to the front positioning groove 3.1 of the hinge joint 3 to achieve the locked state.

[0043] In this design, the rotating ladder device is used on the combine harvester. When the operator needs to enter the cab via the rotating ladder 5, moving the handle 5.11 on the floor will disengage the lock 5.3 connected to the pull plate 5.7 from the positioning groove 3.1 of the hinge joint 3, thus opening the cab. Simultaneously, the rotating ladder 5 is pushed to rotate 90° backward to the side of the left walkway assembly. The pull plate 5.7 is continuously pulled by the tension spring 5.8, and together with the pull plate 5.7, it returns to the side positioning groove 3.1 of the hinge joint 3, achieving the locking state. At this time, the position of the rotating ladder 5 corresponds to the left door of the cab, allowing the operator to easily enter the cab 20 via the ladder. When the operator needs to perform harvesting operations, they can stand on the left walkway assembly and rotate the flower-shaped knob 5.5. This will trigger the lock head 5.3 to disengage from the positioning groove 3.1 of the hinge joint 3, achieving the open state. Simultaneously, pushing the rotating ladder handrail forward by 90° will cause the lock head 5.3 to return to the front positioning groove 3.1 of the hinge joint 3 under the tension of the spring 5.8, achieving the locked state. This solution uses a combination of two simple mechanisms. By rotating the flower-shaped knob 5.15 and moving the handle 5.11, the extension and retraction of the lock head 5.3 can be achieved, thereby realizing the opening and locking functions of the ladder. Moreover, the limiting and positioning are achieved by the same component, eliminating the need for limit adjustment. This solution has a simple overall structure and is easy to operate. It can be reliably stored on the walkway or on the ground, avoiding excessive width of the entire machine and meeting the safety requirements of combine harvesters when traveling on roads.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A rotating ladder device for a combine harvester cab walkway, comprising a base and a rotating ladder, wherein the rotating ladder is rotatably mounted on the base, characterized in that: The rotating ladder is movable between a retracted position and at least one extended position. The base is provided with a hinge joint, and the rotating ladder is provided with a support hinge that mates with the hinge joint. The hinge joint has at least two locking holes on its side. The locking holes are used to lock the rotating ladder in the retracted position or the extended position, respectively. The rotating ladder is equipped with a locking mechanism that mates with the lock hole. The locking mechanism includes a lock head that matches the shape of the lock hole and a pull rod assembly. The lock head extends into the corresponding lock hole to lock the rotating ladder in the corresponding retracted or extended position. One end of the lock head is hinged to the pull rod assembly. Under the action of the pull rod assembly, the lock head can be pulled out of the lock hole to unlock, so that the rotating ladder and the base are in a state of relative rotation. The pull rod assembly includes a pull plate and a pull handle. The first end of the pull plate is hinged to the lock head, and the second end of the pull plate is hinged to the pull handle. A tension spring is also connected to the middle section of the pull plate, and the other end of the tension spring is fixed to the rotating ladder. Under the tension of the tension spring, the lock head can automatically reset and enter the corresponding lock hole in its natural state to lock the rotating ladder. The middle section hinge point of the pull handle is rotatably connected to the rotating ladder. The pull handle is divided into two sections through the middle section hinge point. The first section of the pull handle is hinged to the pull plate, and the second section of the pull handle is hinged to the first end of the connecting rod. The second end of the connecting rod is hinged to the lower end of the control rod welded component. The control rod welded component is rotatably mounted on the rotating ladder and passes through the rotating ladder from bottom to top. A flower-shaped knob is provided at the upper end of the control rod welded component. The control rod welded component includes a control rod body and a control rod connecting plate fixedly disposed at the lower end of the control rod body. The hinge point between the control rod connecting plate and the connecting rod can rotate around the control rod body as the axis.

2. The rotating ladder device for the cab walkway of a combine harvester according to claim 1, characterized in that: The lock head sleeve is fixed to the hinged end of the rotating ladder, and the lock head sleeve is provided with a sliding hole for the lock head to move in the extension and retraction direction.

3. The rotating ladder device for the cab walkway of a combine harvester according to claim 1, characterized in that: The control lever connecting plate is equipped with a limit arm. When the lock head is pulled out of the lock hole, the lock head, pull plate, handle, connecting rod, and control lever connecting plate are linked in sequence, thereby causing the limit arm to rotate and abut against the stop plate to limit the pull-out position of the lock head.

4. The rotating ladder device for the cab walkway of a combine harvester according to claim 1, characterized in that: The rotating ladder is equipped with a positioning pin, which is located on one side of the lock head. When the rotating ladder rotates to the retracted position, the positioning pin abuts against the side of the base, and the lock head can be locked into the corresponding lock hole.

5. The rotating ladder device for the cab walkway of a combine harvester according to claim 1, characterized in that: The two keyholes are arranged at a 90° angle.

6. The rotating ladder device for the cab walkway of a combine harvester according to claim 1, characterized in that: The hinge joint is provided with a vertical shaft hole, and the outer side wall of the hinge joint is provided with a corresponding locking hole. The supporting hinge member includes an upper hinge member and a lower hinge member. The upper hinge member and the lower hinge member are vertically aligned and are provided with corresponding bushings. The bushings correspond to the vertical shaft hole, and the hinge shaft passes through the bushings and the vertical shaft hole in sequence to realize the rotatable connection between the hinge joint and the supporting hinge member.

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