Adjustable chain wheel mechanism of truck top cover

Abstract

The utility model discloses an adjustable chain wheel mechanism of a truck top cover, which comprises a first mounting seat and a second mounting seat which are fixed on a truck box body, an adjusting seat is movably arranged on the second mounting seat, and a second guide wheel is rotatably arranged on the adjusting seat, so that when the adjusting seat drives the second guide wheel to move close to the second mounting seat, the second guide wheel is driven to move close to the second mounting seat. The first driving wheel and the second guiding wheel tighten the adjusting chain, the first operation section moves in a reciprocating mode under driving of the first driving wheel to pull the second operation section to move in a reciprocating mode, and the top cover is driven to be close to be closed or far away from be opened for operation. Relative displacement of the second guide wheel can be directly driven through relative movement of the adjusting seat, so that the relative distance between the first driving wheel and the second guide wheel is changed, the tightening degree of the adjusting chain is changed, adaptive adjustment in the opening and closing control process of the top cover is kept, and reliable operation is kept.

Description

Technical Field

[0001] The present application relates to the technical field of railway freight cars, and in particular to an adjustable sprocket mechanism for a freight car roof. Background Art

[0002] The information provided in this section is for the purpose of generally presenting the background of the present disclosure. To the extent described in this section, the work of the presently named inventors and aspects of the description that may not constitute prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art to the present disclosure.

[0003] The safety and environmental issues of railway freight transportation are becoming increasingly prominent. Adding a roof to the vehicle to isolate and protect the cargo is the development direction of railway freight cars. The longitudinal double-opening stacked plate roof has become the main structural type of railway freight car roof due to its simple structure and small space occupancy.

[0004] In the existing longitudinal split stacked plate top cover structure, in order to ensure the reliable opening and closing of the top cover, the chain and wire rope need to be tensioned. On existing vehicles, a two-way screw is generally used for tightening. Due to the limitations of operating space, differences in upper and lower structure, and chain positioning requirements, it is difficult to inspect and maintain during use. Utility Model Content

[0005] In view of the defects existing in the prior art, the present application provides an adjustable sprocket mechanism for a truck roof to solve the problem of complex operation and maintenance of the tightening structure in the prior art.

[0006] The above-mentioned purpose of the present application is mainly achieved through the following technical solutions:

[0007] An adjustable sprocket mechanism for a truck roof, the adjustable sprocket mechanism comprising:

[0008] A first mounting seat, the first mounting seat is used to be fixed on the truck body, and the first mounting seat is provided with a first driving wheel;

[0009] A second mounting seat, the second mounting seat is used to be fixed on the truck box body, and the second mounting seat is provided with a second guide wheel;

[0010] An adjusting chain, the adjusting chain is sleeved on the first driving wheel and the second guide wheel at the same time, the adjusting chain has a first working section that is chain-driven with the first driving wheel, and a second working section that is used to connect the top cover, and when the first driving wheel drives the first working section to reciprocate, the second working section reciprocates synchronously and drives the top cover to open or close;

[0011] The adjusting seat is movably arranged on the second mounting seat, and the second guide wheel is rotatably arranged on the adjusting seat, so that when the adjusting seat drives the second guide wheel to move close to the second mounting seat, the first driving wheel and the second guide wheel tighten the adjusting chain.

[0012] In an optional embodiment, two connecting parts are provided on the second working section, and connecting holes are respectively provided on the two connecting parts for respectively connecting the two top covers that can be close to or away from each other.

[0013] In an optional embodiment, a constraint portion is provided between the first working section and the second working section. When the first driving wheel drives the first working section to reciprocate, the constraint portion may abut against the first driving wheel or the second guide wheel to restrict the first working section from continuing to move.

[0014] In an optional embodiment, a convex portion is provided on the constraint portion for abutting against the first driving wheel or the second guide wheel.

[0015] In an optional embodiment, the adjustment seat includes a sliding portion, a connecting portion and a locking portion, the second mounting seat is provided with a sliding groove for accommodating the sliding portion, the second guide wheel is arranged at one end of the sliding portion, the locking portion is threadedly connected to the connecting portion, and is used to be pressed on one side of the second mounting seat so that when the locking portion is rotated to different positions on the connecting portion, the sliding portion slides to different positions in the sliding groove.

[0016] In an optional embodiment, the cross-section of the sliding portion is polygonal to limit the sliding portion from rotating in the sliding groove.

[0017] In an optional embodiment, a connecting seat is provided on the adjusting seat, and a rotating shaft passing through the second guide wheel is provided on the connecting seat.

[0018] In an optional embodiment, a third constraint wheel which is chain-driven with the first working section is further provided on the first mounting seat, and the third constraint wheel is located on the inner side of the adjustment chain to change the extension direction of the first working section.

[0019] In an optional embodiment, a fourth constraint wheel driven by the first working section chain is further provided on the first mounting seat, and the fourth constraint wheel is located outside the adjustment chain so that the middle part of the adjustment chain is arranged horizontally.

[0020] In an optional embodiment, the first working section is a chain, and the second working section is a wire rope.

[0021] Compared with the prior art, the advantages of this application are:

[0022] The adjustable sprocket mechanism in the present application includes a first mounting seat and a second mounting seat fixed on the truck body, the first mounting seat is provided with a first driving wheel, the second mounting seat is provided with a second guide wheel, an adjusting chain is sleeved on the first driving wheel and the second guide wheel, the adjusting chain has a first working section that is chain-driven with the first driving wheel, and a second working section for connecting the top cover, and when the first driving wheel drives the first working section to reciprocate, the second working section reciprocates synchronously and drives the top cover to open or close, an adjusting seat is movably provided on the second mounting seat, and the second guide wheel is rotatably provided on the adjusting seat, so that the adjusting seat drives the second guide wheel to move close to the second mounting seat When the first driving wheel and the second guiding wheel are in motion, the adjusting chain is tightened by the first driving wheel and the second guiding wheel. During actual operation, the top covers that are used to move closer to each other for closing and farther away from each other for opening are respectively arranged on the second operating section. Driven by the first driving wheel, the first operating section reciprocates and pulls the second operating section to move reciprocally, driving the top cover to move closer to closing or farther away from opening. When a certain operating error or driving clearance occurs in the adjusting chain, the relative movement of the adjusting seat can directly drive the relative displacement of the second guiding wheel, thereby changing the relative distance between the first driving wheel and the second guiding wheel, changing the tightness of the adjusting chain, maintaining adaptive adjustment in the process of opening and closing control of the top cover, and maintaining reliable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 A structural schematic diagram of an adjustable sprocket mechanism is provided for an embodiment of the present application;

[0025] Figure 2 A partial enlarged schematic diagram of the adjustment seat is provided for the embodiment of the present application;

[0026] In the figure: 101, first mounting seat; 102, first driving wheel; 201, second mounting seat; 202, second guide wheel; 301, first working section; 302, second working section; 303, connecting part; 304, connecting hole; 305, restraining part; 306, convex part; 400, adjusting seat; 401, sliding part; 402, connecting part; 403, locking part; 501, connecting seat; 502, rotating shaft; 503, third restraining wheel; 504, fourth restraining wheel. DETAILED DESCRIPTION

[0027] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. The specific structural and functional details disclosed herein are only used to describe the exemplary embodiments of the present invention. However, the present invention can be embodied in many alternative forms, and it should not be understood that the present invention is limited to the embodiments described herein.

[0028] Figure 1 A schematic diagram of the structure of an adjustable sprocket mechanism is provided for the embodiment of the present application. Figure 2 A partial enlarged schematic diagram of the adjustment seat 400 is provided for the embodiment of the present application.

[0029] like Figure 1 and Figure 2 As shown, an adjustable sprocket mechanism for a truck roof, the adjustable sprocket mechanism comprises a first mounting seat 101, a second mounting seat 201, an adjustment chain and an adjustment seat 400, wherein:

[0030] The first mounting seat 101 is used to be fixed on the truck body, and a first driving wheel 102 is provided on the first mounting seat 101. The first mounting seat 101 on the truck body is a key structural component for fixing, supporting and connecting various components. Its design and manufacture take into account load-bearing, durability and safety. The first driving wheel 102 on the first mounting seat 101 serves as an active driving member. Under active operation, it can provide driving power. The rotation of the first driving wheel 102 can be achieved by manual operation or by connecting a driving motor. During the driving process of the first driving wheel 102, the first driving wheel 102 is driven to rotate forward or reverse to achieve driving needs in different directions.

[0031] like Figure 1 and Figure 2 As shown, the second mounting seat 201 is used to be fixed on the truck body, and a second guide wheel 202 is provided on the second mounting seat 201. The second mounting seat 201 on the truck body is a key structural component for fixing, supporting and connecting various components. Similarly, its design and manufacture take into account load-bearing, durability and safety. The second guide wheel 202 on the second mounting seat 201 serves as a driven component and can be driven to rotate by an external force. During the process of the second guide wheel 202 being driven to rotate, the second guide wheel 202 is driven to rotate forward or reverse to achieve the guidance needs in different directions. It should be noted that the installation position of the second mounting seat 201 is installed in an area that is convenient for manual operation, and the rotation state of the second guide wheel 202 is free rotation, that is, it can follow the rotation under the drive of external force.

[0032] like Figure 1 and Figure 2As shown, the adjustment chain is simultaneously mounted on the first driving wheel 102 and the second guide wheel 202, and the adjustment chain has a first working section 301 that is chain-driven with the first driving wheel 102, and a second working section 302 that is used to connect the top cover, and when the first driving wheel 102 drives the first working section 301 to reciprocate, the second working section 302 reciprocates synchronously and drives the top cover to open or close.

[0033] The adjusting chain is simultaneously mounted on the first driving wheel 102 and the second guide wheel 202. Driven by the active rotation of the first driving wheel 102, the adjusting chain can rotate in different directions. The first working section 301 and the first driving wheel 102 are in a reliable chain transmission state, and the overall rotation of the adjusting chain is maintained. The connection between the second working section 302 and the top cover enables the top cover to be displaced synchronously when the adjusting chain rotates as a whole, thereby achieving the set displacement effect.

[0034] like Figure 1 and Figure 2 As shown, the adjusting seat 400 is movably arranged on the second mounting seat 201, and the second guide wheel 202 is rotatably arranged on the adjusting seat 400, so that when the adjusting seat 400 drives the second guide wheel 202 to move close to the second mounting seat 201, the first driving wheel 102 and the second guide wheel 202 tighten the adjusting chain, and through the active operation of the operator, the adjusting seat 400 can be operated to move close to or away from the second mounting seat 201 according to the working conditions, thereby changing the distance between the first mounting seat 101 and the adjusting seat 400.

[0035] In an optional embodiment, the working principle of the adjustable sprocket mechanism in the present application is: the adjustable sprocket mechanism includes a first mounting seat 101 and a second mounting seat 201 fixed on the truck body, the first mounting seat 101 is provided with a first driving wheel 102, the second mounting seat 201 is provided with a second guide wheel 202, an adjustment chain is sleeved on the first driving wheel 102 and the second guide wheel 202, the adjustment chain has a first working section 301 chain-driven with the first driving wheel 102, and a second working section 302 for connecting the top cover, and when the first driving wheel 102 drives the first working section 301 to reciprocate, the second working section 302 reciprocates synchronously and drives the top cover to open or close, an adjustment seat 400 is movably provided on the second mounting seat 201, and the second guide wheel 202 is rotatably provided on the adjustment seat 400 so that When the adjustment seat 400 drives the second guide wheel 202 to move close to the second mounting seat 201, the first driving wheel 102 and the second guide wheel 202 tighten the adjustment chain. During actual operation, the top covers that are used to move closer to each other for closing and farther away from each other for opening are respectively arranged on the second working section 302. Driven by the first driving wheel 102, the first working section 301 moves back and forth to pull the second working section 302 to move back and forth, driving the top cover to move closer to closing or away from opening. When a certain operating error or driving clearance occurs in the adjustment chain, the relative movement of the adjustment seat 400 can directly drive the relative displacement of the second guide wheel 202, thereby changing the relative distance between the first driving wheel 102 and the second guide wheel 202, changing the tightness of the adjustment chain, maintaining adaptive adjustment during the top cover opening and closing control process, and maintaining reliable operation.

[0036] like Figure 1 and Figure 2 As shown, in an optional embodiment, two connecting parts 303 are provided on the second working section 302, and connecting holes 304 are respectively provided on the two connecting parts 303 for respectively connecting the two top covers that can be close to or away from each other.

[0037] like Figure 1 and Figure 2 As shown, the connecting portion 303 is arranged on the second working section 302, and the top cover is connected and installed through the connecting hole 304 on the connecting portion 303. Specifically, the two connecting portions 303 are respectively arranged on both sides of the second guide wheel 202. When the second working section 302 is pulled and moved by the first working section 301, the two connecting portions 303 also follow and move synchronously. The projections of the two connecting portions 303 on the top cover form a relationship of approaching or moving away from each other, thereby driving the two top covers to a closed or opened working state.

[0038] During actual maintenance or calibration operations, the connection part 303 and the top cover can be disassembled and separated, and adjustment and maintenance can be performed with reference to the connection part 303. This is more convenient, especially in railway freight car loading and unloading areas or in complex structural conditions of freight cars, and has better operability.

[0039] like Figure 1 and Figure 2 As shown, in an optional embodiment, a constraint portion 305 is provided between the first working section 301 and the second working section 302. When the first driving wheel 102 drives the first working section 301 to reciprocate, the constraint portion 305 can abut against the first driving wheel 102 or the second guide wheel 202 to limit the first working section 301 from continuing to move.

[0040] It should be noted that, due to the limited area of ​​the loading port on the railway freight car, the displacement stroke of the top cover on the railway freight car is also determined. In order to avoid increased costs or increased operating difficulty caused by precise control of the first driving wheel 102, a constraint portion 305 is set between the first working section 301 and the second working section 302, and the constraint portion 305 is used to limit the distance that the first working section 301 can be effectively driven by the first driving wheel 102, thereby preventing the movement distance of the adjustment chain from exceeding the set distance, thereby avoiding excessive opening or excessive closing of the top cover, and improving the stability of the top cover.

[0041] Specifically, during the process of synchronous movement of the first working section 301, the constraint portion 305 can abut against the first driving wheel 102 or the second guide wheel 202, and through the restriction of mutual abutment, the first working section 301 is prevented from continuing to move after the abutment, thereby maintaining the stability of the process of the adjustment chain driving the top cover to move, and protecting the structural reliability of the first driving wheel 102 and the adjustment chain.

[0042] like Figure 1 and Figure 2 As shown, in an optional embodiment, a convex portion 306 is provided on the constraint portion 305 to abut against the first driving wheel 102 or the second guide wheel 202 .

[0043] In actual arrangement, the two ends of the constraint part 305 are respectively connected to the first working section 301 and the second working section 302, and the constraint part 305 follows the first working section 301 and the second working section 302 to move back and forth synchronously, and when the constraint part 305 follows and moves to the first driving wheel 102 or the second guide wheel 202, when the constraint part 305 is pulled and moves and wants to cross the first driving wheel 102 or the second guide wheel 202, the convex part 306 on the constraint part 305 and the first driving wheel 102 or the second guide wheel 202 are mutually supported. At this time, the first working section 301, the second working section 302 and the constraint part 305 cannot continue to move in the set direction. Correspondingly, the top cover is at the extreme position of opening or closing at this time, which reduces the control difficulty and control accuracy and improves the reliability during the operation.

[0044] like Figure 1 and Figure 2 As shown, in an optional embodiment, the adjustment seat 400 includes a sliding portion 401, a connecting portion 303 and a locking portion 403, the second mounting seat 201 is provided with a sliding groove for accommodating the sliding portion 401, the second guide wheel 202 is provided at one end of the sliding portion 401, the locking portion 403 is threadedly connected to the connecting portion 303, and is used to be pressed on one side of the second mounting seat 201, so that when the locking portion 403 is rotated to different positions on the connecting portion 303, the sliding portion 401 slides to different positions in the sliding groove.

[0045] The locking portion 403 is then rotated until one side of the locking portion 403 is pressed against the side wall of the second mounting seat 201. The adjustment operation is then completed and the adjustment chain can be disassembled, replaced, or otherwise removed.

[0046] like Figure 1 and Figure 2 As shown, in an optional embodiment, the cross-section of the sliding portion 401 is a polygon to limit the rotation of the sliding portion 401 in the sliding groove.

[0047] By setting the cross section of the sliding part 401 to be polygonal, the cross section of the slide groove is correspondingly matched with the sliding part 401, thereby preventing the sliding part 401 from rotating in the slide groove. Synchronously, the second guide wheel 202 on the sliding part 401 is also prevented from rotating, thereby improving the stability of the second guide wheel 202 and preventing the adjustment chain from being entangled.

[0048] In an optional embodiment, a connecting seat 501 is provided on the adjusting seat 400 , and a rotating shaft 502 penetrating the second guide wheel 202 is provided on the connecting seat 501 .

[0049] The second guide wheel 202 is mounted on the connecting seat 501 via the rotating shaft 502, and there is a gap between the inner wall of the connecting seat 501 and the outer peripheral surface of the second guide wheel 202 for the adjusting chain to pass through, so as to maintain the movement stability of the adjusting chain.

[0050] In an optional embodiment, in an optional embodiment, a third constraint wheel 503 chain-driven with the first working section 301 is further provided on the first mounting seat 101 , and the third constraint wheel 503 is located on the inner side of the adjustment chain to change the extension direction of the first working section 301 .

[0051] A third constraint wheel 503 is added and arranged on the inner side of the adjustment chain like the first driving wheel 102. The first driving wheel 102 provides power for the movement of the adjustment chain. The arrangement of the third constraint wheel 503 facilitates guiding the first working section 301 to extend in different directions, so as to constrain the adjustment chain to complete reciprocating movement within the set guiding range, thereby improving operation reliability.

[0052] In an optional embodiment, a fourth constraint wheel 504 which is chain-driven with the first working section 301 is further provided on the first mounting seat 101 , and the fourth constraint wheel 504 is located outside the adjustment chain so that the middle part of the adjustment chain is arranged horizontally.

[0053] A fourth constraint wheel 504 is added and arranged on the outside of the adjusting chain. When the fourth constraint wheel 504 is arranged, the middle part of the adjusting chain is kept horizontally arranged. In other words, the top cover connected to the second working section 302 is kept to reciprocate in the horizontal direction through the fourth constraint wheel 504, thereby improving the operating reliability of the top cover and avoiding the tilting movement of the top cover caused by the adjusting chain.

[0054] In an optional embodiment, the first working section 301 is a chain, and the second working section 302 is a steel wire rope. The chain maintains a stable chain connection with the first driving wheel 102, and the steel wire rope maintains repeated operation reliability with reliable tensile strength.

[0055] It should be understood that the terms first, second, etc. are only used to distinguish descriptions and should not be understood as indicating or implying relative importance. Although the terms first, second, etc. may be used herein to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another unit. For example, the first unit may be referred to as the second unit, and similarly, the second unit may be referred to as the first unit without departing from the scope of the exemplary embodiments of the present utility model.

[0056] It should be understood that the term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent three situations: A exists alone, B exists alone, and A and B exist at the same time. The term " / and" in this article describes another relationship between associated objects, indicating that two relationships may exist. For example, A / and B can represent two situations: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the previous and next associated objects are in an "or" relationship.

[0057] It should be understood that in the description of the present invention, the terms "upper", "vertical", "inside", "outside", etc. indicate orientations or positional relationships that are customarily placed when the disclosed product is used, or are orientations or positional relationships that are customarily understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0058] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0059] The terms used herein are only used to describe specific embodiments and are not intended to limit the exemplary embodiments of the utility model. As used herein, the singular forms "one", "an", and "the" are intended to include plural forms unless the context clearly indicates the opposite meaning. It should also be understood that the terms "include", "comprise", "include", and / or "comprising" when used herein specify the existence of the claimed features, integers, steps, operations, units, and / or components, and do not exclude the existence or increase of one or more other features, quantities, steps, operations, units, components, and / or their combinations.

[0060] Specific details are provided in the following description to facilitate a complete understanding of the exemplary embodiments. However, it should be understood by those of ordinary skill in the art that the exemplary embodiments may be implemented without these specific details. In other embodiments, well-known processes, structures, and techniques may not be shown in unnecessary detail to avoid making the exemplary embodiments unclear.

[0061] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

[0062] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field.

Claims

1. An adjustable sprocket mechanism for a truck roof, characterized in that: The adjustable sprocket mechanism comprises: A first mounting seat, the first mounting seat is used to be fixed on the truck body, and the first mounting seat is provided with a first driving wheel; A second mounting seat, the second mounting seat is used to be fixed on the truck box body, and the second mounting seat is provided with a second guide wheel; An adjusting chain, the adjusting chain is sleeved on the first driving wheel and the second guide wheel at the same time, the adjusting chain has a first working section that is chain-driven with the first driving wheel, and a second working section that is used to connect the top cover, and when the first driving wheel drives the first working section to reciprocate, the second working section reciprocates synchronously and drives the top cover to open or close; The adjusting seat is movably arranged on the second mounting seat, and the second guide wheel is rotatably arranged on the adjusting seat, so that when the adjusting seat drives the second guide wheel to move close to the second mounting seat, the first driving wheel and the second guide wheel tighten the adjusting chain.

2. The adjustable sprocket mechanism for a truck roof as claimed in claim 1, characterized in that: The second operation section is provided with two connecting parts, and the two connecting parts are respectively provided with connecting holes for respectively connecting the two top covers which can be close to or far away from each other.

3. The adjustable sprocket mechanism for a truck roof as claimed in claim 2, characterized in that: A constraint portion is provided between the first working section and the second working section. When the first driving wheel drives the first working section to reciprocate, the constraint portion can abut against the first driving wheel or the second guide wheel to restrict the first working section from continuing to move.

4. The adjustable sprocket mechanism for a truck roof as claimed in claim 3, characterized in that: The restraining portion is provided with a convex portion for abutting against the first driving wheel or the second guide wheel.

5. The adjustable sprocket mechanism for a truck roof as claimed in claim 1, characterized in that: The adjustment seat includes a sliding portion, a connecting portion and a locking portion. The second mounting seat is provided with a sliding groove for accommodating the sliding portion. The second guide wheel is arranged at one end of the sliding portion. The locking portion is threadedly connected to the connecting portion and is used to be pressed on one side of the second mounting seat so that when the locking portion is rotated to different positions on the connecting portion, the sliding portion slides to different positions in the sliding groove.

6. The adjustable sprocket mechanism for a truck roof as claimed in claim 5, characterized in that: The cross section of the sliding part is polygonal so as to limit the sliding part from rotating in the sliding groove.

7. The adjustable sprocket mechanism for a truck roof as claimed in claim 5, characterized in that: The adjusting seat is provided with a connecting seat, and the connecting seat is provided with a rotating shaft penetrating the second guide wheel.

8. The adjustable sprocket mechanism for a truck roof as claimed in claim 5, characterized in that: The first mounting seat is also provided with a third constraint wheel which is chain-driven with the first working section. The third constraint wheel is located inside the adjusting chain to change the extension direction of the first working section.

9. The adjustable sprocket mechanism for a truck roof as claimed in claim 8, characterized in that: The first mounting seat is also provided with a fourth constraint wheel which is chain-driven with the first working section. The fourth constraint wheel is located outside the adjusting chain so that the middle part of the adjusting chain is arranged horizontally.

10. The adjustable sprocket mechanism for a truck roof as claimed in claim 5, characterized in that: The first working section is a chain, and the second working section is a wire rope.

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