A rear expansion frame structure of a trailer house

Abstract

The present application relates to a kind of trailer house rear extension frame structure, including hanger, tire rack and material rack;Hanger includes the installation frame and the storage rack connected;Tire rack includes fixed tire rack and top tire rack, fixed tire rack and top tire rack are installed at the storage rack with interval, fixed tire rack is equipped with fixed part, fixed part is arranged with interval between storage rack, top tire rack is equipped with top tire part, top tire part is arranged with interval at the side of fixed part close to storage rack, and the distance between it and storage rack is adjustable;Material rack is installed in storage rack, and is located at the side of fixed tire rack away from top tire rack.This scheme improves the stability of spare tire installation;And top tire part can support different outer diameter of spare tire, improve practicality.And, in this scheme, material rack is also provided at the side of fixed tire rack away from top tire rack, material rack can load material such as bicycle, improve the practicality of extension frame;And since material rack and spare tire are located on the opposite sides of fixed tire rack, can avoid the load on material rack accidentally damage spare tire, ensure safety performance.

Description

Technical Field

[0001] This invention relates to the field of RV extension structure technology, and more particularly to a rear extension frame structure for a towed RV. Background Technology

[0002] To enhance the functionality of towed caravans and provide customers with more outdoor enjoyment, an extension rack structure can be added to the rear of existing caravans. This extension rack can be used to store spare tires, motorcycles, bicycles, etc. For example, patent CN210258596 U discloses a foldable extendable spare tire rack and a vehicle using it. By setting a foldable support body, it reduces the overall space occupied and effectively avoids interference with the vehicle body, making it safer and more reliable to use. However, this patent only allows for the installation of the spare tire via the spare tire mounting bracket, which needs improvement in practicality. Furthermore, the spare tire is only secured by screws on the spare tire mounting bracket, resulting in relatively poor installation stability. Summary of the Invention

[0003] In view of this, it is necessary to provide a rear extension rack structure for a towed caravan to solve the technical problems of existing extension racks that can only install the spare tire via the spare tire mounting bracket, which requires improvement in practicality and has relatively poor installation stability of the spare tire.

[0004] This invention provides a rear extension rack structure for a towed caravan, the rear extension rack structure comprising:

[0005] The bracket includes a mounting bracket and a shelf connected together, wherein the end of the mounting bracket away from the shelf is used to be mounted on the vehicle body, so that the shelf can extend out of the vehicle body;

[0006] A tire holder includes a fixed tire holder and a top tire holder, the fixed tire holder and the top tire holder being installed at a distance from each other on a shelf. The fixed tire holder has a fixing part, which is spaced apart from the shelf and used to fix the inner ring of the spare tire. The top tire holder has a top tire part, which is spaced apart from the fixing part on the side near the shelf and used to support the outer ring of the spare tire. The distance between the top tire part and the shelf is adjustable.

[0007] A material rack is installed on the shelf and located on the side of the fixed frame away from the top frame, and is provided with a loading part for loading materials.

[0008] Optionally, the top tire frame includes a support frame, a top tire screw, and two adjusting nuts. The support frame is fixed to the shelf and is spaced apart on the side of the fixing part near the shelf, and has a stop hole facing the fixing part. One end of the top tire screw passes through the stop hole, and the other end points to the fixing part. The two adjusting nuts are screwed onto the top tire screw and are respectively located at both ends of the stop hole. The top tire part is located at the end of the top tire screw pointing to the fixing part.

[0009] Optionally, the top tire frame further includes a limiting tube, the inner cavity of which is polygonal and is movably sleeved along its axial direction at one end of the top tire screw where the top tire part is located, and its side wall is provided with an avoidance opening communicating with the inner cavity.

[0010] The portion of the top screw located in the inner cavity is polygonal, and one of the two adjusting nuts is a wing nut. The wing nut is located at the end of the stop hole near the fixing part and is placed in the inner cavity of the limiting tube, with its wing-shaped handle extending out of the clearance opening.

[0011] Optionally, the support frame is provided with a guide channel in a direction away from the stop hole. The guide channel is polygonal and its size is larger than that of the guide hole.

[0012] One of the two adjusting nuts is a limiting screw sleeve, which is located inside the guide channel and its outer wall is polygonal in shape corresponding to the guide channel.

[0013] Optionally, two top tire frames are provided, with the two top tire frames spaced apart on both sides of the fixing part;

[0014] The top tire portion is a top tire piece, which is installed on the corresponding top tire frame, and each top tire piece is inclined from one end near the fixed part to the end away from the fixed part toward the other top tire piece.

[0015] Optionally, the top tire frame is provided with a connecting hole, and the top tire piece is provided with a mating hole corresponding to the connecting hole;

[0016] The tire frame also includes connecting bolts and connecting nuts. One end of the connecting bolt passes through the connecting hole and the mating hole, and the connecting nut is screwed onto the connecting bolt, so that the tilt angle of the top tire piece is adjustable.

[0017] Optionally, the shelf is provided with a fixed tube, and the fixed frame is provided with a tube clamp corresponding to the fixed tube. The tube clamp is sleeved on the outer wall of the fixed tube and fastened to the fixed tube by a screw connector, so that the fixed frame can rotate relative to the fixed tube around the axis of the fixed tube when the screw connector is loosened.

[0018] Optionally, the fixing part is a fixing plate, which is located on the side of the tire fixing frame away from the material rack and has a fixing hole for threaded parts to pass through, so as to fix the spare tire to the fixing plate.

[0019] Optionally, the material rack includes a main frame, fasteners, and two side frames. The main frame is disposed on the shelf and located on the side of the fixed frame away from the top frame. The two side frames are respectively installed at both ends of the main frame, and at least one side frame can move away from the other side frame, so that the distance between the two side frames is adjustable. The fasteners are disposed between each side frame and the main frame to restrict the movement of the side frame relative to the main frame after the distance between the two side frames is adjusted to a preset distance.

[0020] Optionally, the main frame and the two side frames are provided with a plurality of fastening holes along the arrangement direction of the two side frames, and the loading part is a loading hole provided on the main frame and the side frames;

[0021] The fasteners include multiple sets of fastening bolts and fastening nuts. The fastening bolts are inserted into the fastening holes of the side frames of the main frame, and the fastening nuts are screwed onto the fastening bolts, so that the distance between the two side frames is adjustable.

[0022] Compared with existing technologies, the trailer caravan extension rack structure provided by this invention fixes the mounting rack to the caravan body and allows the storage rack to extend outside the vehicle body. This facilitates the fixing of the spare tire's inner ring via the fixing part, ensuring the spare tire is securely fixed to the rack without interfering with the vehicle body. Simultaneously, the top tire part of the top tire rack supports the outer ring of the spare tire, improving the stability of the spare tire installation. Furthermore, since the distance between the top tire part and the storage rack is adjustable, the distance between the top tire part and the fixing part can be adjusted, allowing the top tire part to support spare tires of different outer diameters, improving practicality. In addition, this solution includes a material rack on the side of the tire rack away from the top tire rack, which can hold materials such as bicycles, further enhancing the practicality of the extension rack. Moreover, since the material rack and the spare tire are located on opposite sides of the tire rack, accidental damage to the spare tire by items on the material rack is prevented, ensuring safety.

[0023] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail in the following embodiments and their accompanying drawings. Attached Figure Description

[0024] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0025] Figure 1 This is a schematic diagram of an embodiment of the rear extension frame structure for a trailer caravan provided by the present invention.

[0026] Figure 2 for Figure 1 A schematic diagram of the rear extension frame structure of a mid-length trailer caravan with a spare tire installed.

[0027] Figure 3 for Figure 1 Schematic diagram of the structure of the center-top frame;

[0028] Figure 4 for Figure 3 Exploded view of the central roof tire frame;

[0029] Figure 5 for Figure 3 Cross-sectional view of the central top frame;

[0030] Figure 6 for Figure 5 A sectional view of the central support frame;

[0031] Figure 7 for Figure 3 Schematic diagram of the middle limiting tube;

[0032] Figure 8 for Figure 1 Schematic diagram of the middle rack;

[0033] Figure 9 for Figure 1 Schematic diagram of the structure of the central solid frame;

[0034] Figure 10 for Figure 1 Exploded view of the material rack, license plate frame, mating sleeve and stop sleeve;

[0035] Figure 11 for Figure 10 Cross-sectional view of the material rack, license plate frame, mating sleeve and stop sleeve;

[0036] Figure 12 for Figure 10 Exploded view of the central material rack;

[0037] Figure 13 for Figure 12 Enlarged diagram of point A in the middle.

[0038] Explanation of reference numerals in the attached figures:

[0039] 100. Rear Extension Rack Structure of a Trailer Caravan; 1. Mounting Rack; 2. Storage Rack; 21. Fixing Pipe; 22. Connecting Pipe; 23. Matching Sleeve; 24. Stop Sleeve; 25. Limiting Handle; 3. Tire Mounting Rack; 31. Fixing Part; 311. Fixing Plate; 32. Pipe Clamp; 4. Top Tire Mounting Rack; 4a. Connecting Hole; 41. Top Tire Part; 411. Top Tire Plate; 42. Support Frame; 42a. Stop Hole; 42b. Guide Channel; 42c. Mounting Slot; 42 d. Insertion hole; 43. Top tire screw; 44. Adjusting nut; 441. Wing nut; 442. Limiting screw sleeve; 45. Limiting tube; 45a. Clearance opening; 5. Material rack; 5a. Fastening hole; 51. Loading part; 51a. Loading hole; 52. Main frame; 521. Main plate; 522. Extension plate; 53. Side frame; 54. Fastener; 55. Mounting sleeve; 56. License plate sleeve; 6. License plate frame; 61. Extension tube; 200. Spare tire. Detailed Implementation

[0040] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0041] Please see Figures 1 to 13 The rear extension rack structure 100 of this trailer caravan includes a hanging rack, a tire rack, and a material rack 5. The hanging rack includes a mounting bracket 1 and a storage rack 2 connected together. The end of the mounting bracket 1 away from the storage rack 2 is used to install on the vehicle body, so that the storage rack 2 can extend out of the vehicle body. The tire rack includes a fixed tire rack 3 and a top tire rack 4. The fixed tire rack 3 and the top tire rack 4 are installed at intervals on the storage rack 2. The fixed tire rack 3 has a fixing part 31, which is spaced apart from the storage rack 2 to fix the inner ring of the spare tire 200. The top tire rack 4 has a top tire part 41, which is spaced apart on the side of the fixing part 31 near the storage rack 2 to support the outer ring of the spare tire 200, and the distance between it and the storage rack 2 is adjustable. The material rack 5 is installed on the storage rack 2 and is located on the side of the fixed tire rack 3 away from the top tire rack 4, and has a loading part 51 for loading materials.

[0042] In the trailer caravan rear extension frame structure 100 provided by the present invention, the mounting frame 1 is fixed to the vehicle body of the trailer caravan, and the storage rack 2 can extend out of the vehicle body, thereby facilitating the fixing frame 3 to fix the inner ring of the spare tire 200 through the fixing part 31, so that the spare tire 200 is fixed on the fixing frame 3 without interfering with the vehicle body; at the same time, the outer ring of the spare tire 200 is supported by the top tire part 41 of the top tire frame 4, improving the stability of the spare tire 200 installation; and since the distance between the top tire part 41 and the storage rack 2 is adjustable, that is, the distance between the top tire part 41 and the fixing part 31 can be adjusted, so the top tire part 41 can support spare tires 200 with different outer diameters, improving practicality. Furthermore, in this design, a material rack 5 is provided on the side of the fixed tire frame 3 away from the top tire frame 4. The material rack 5 can be used to load materials such as bicycles, improving the practicality of the extension frame. Since the material rack 5 and the spare tire 200 are located on opposite sides of the fixed tire frame 3, the load on the material rack 5 can be prevented from accidentally damaging the spare tire 200, ensuring safety.

[0043] Furthermore, the top tire frame 4 includes a support frame 42, a top tire screw 43, and two adjusting nuts 44. The support frame 42 is fixed to the shelf 2 and is spaced apart on the side of the fixing part 31 near the shelf 2, and has a stop hole 42a facing the fixing part 31. One end of the top tire screw 43 passes through the stop hole 42a, and the other end points towards the fixing part 31. The two adjusting nuts 44 are screwed onto the top tire screw 43 and are located at both ends of the stop hole 42a. The top tire part 41 is located at the end of the top tire screw 43 that points towards the fixing part 31. In this embodiment, the distance between the top tire part 41 and the shelf 2 is adjusted by adjusting the position of the two adjusting nuts 44 on the top tire screw 43. The structure is simple and the operation is convenient.

[0044] It should be noted that in this design, the shelf 2 is provided with a connecting tube 22, and the connecting tube 22 has pin holes along its radial direction; the support frame 42 is provided with a mounting groove 42c, which is notched to allow the connecting tube 22 to pass through, and the bottom of the mounting groove 42c has an insertion hole 42d corresponding to the pin hole; the top frame 4 also includes a pin, which is inserted into the insertion hole 42d and the pin hole to fix the support frame 42 to the shelf 2. In addition, the connecting tube 22 has multiple pin holes spaced apart along the direction away from the fixed frame 3, so that the position of the support frame 42 on the connecting tube 22 can be adjusted, thereby adjusting the distance between the support frame 42 and the fixed frame 3, improving flexibility.

[0045] Furthermore, the top tire bracket 4 also includes a limiting tube 45. The inner cavity of the limiting tube 45 is polygonal and is movably sleeved along its axis at one end of the top tire screw 43 where the top tire part 41 is provided. Its side wall is provided with a clearance opening 45a that communicates with the inner cavity. The part of the top tire screw 43 located in the inner cavity is polygonal. One of the two adjusting nuts 44 is a wing nut 441. The wing nut 441 is located at one end of the stop hole 42a near the fixing part 31 and is placed in the inner cavity of the limiting tube 45. Its wing shank extends out of the clearance opening 45a. In this embodiment, the limiting tube 45 is first moved axially along the top tire screw 43, so that the wing nut 441 is placed outside the inner cavity of the limiting tube 45. Then, the wing nut 441 is rotated to adjust the length of the other end of the top tire screw 43 extending into the stop hole 42a, thereby adjusting the distance between the top tire part 41 and the fixing part 31. After the distance is adjusted, the limiting tube 45 is moved in the opposite direction, so that the wing nut 441 enters the inner cavity of the limiting tube 45, and the wing shank of the wing nut 441 extends out of the relief opening 45a of the limiting tube 45, preventing the wing nut 441 from rotating relative to the top tire screw 43, thereby preventing unexpected changes in the distance between the top tire part 41 and the shelf 2, and improving stability.

[0046] Furthermore, the support frame 42 is provided with a guide channel 42b in the direction away from the stop hole 42a. The guide channel 42b is polygonal and its size is larger than that of the guide hole. One of the two adjusting nuts 44 is a limiting screw sleeve 442, which is located inside the guide channel 42b, and its outer wall is polygonal corresponding to the guide channel 42b. In this embodiment, the limiting screw sleeve 442 is placed in the guide channel 42b, and the axial rotation of the limiting screw sleeve 442 around the top tire screw 43 is restricted by the external dimensions of both. Thus, after the top tire screw 43 is extended from the stop hole 42a into the guide channel 42b, only the top tire screw 43 needs to be rotated to gradually screw the top tire screw 43 into the limiting screw sleeve 442, improving convenience. It should be noted that in this embodiment, the inner cavity of the limiting tube 45, the guide channel 42b, and the limiting screw sleeve 442 are all rectangular.

[0047] Furthermore, two top tire frames 4 are provided, with the two top tire frames 4 spaced apart on both sides of the fixing part 31; the top tire part 41 is a top tire plate 411, which is installed on the corresponding top tire frame 4, and each top tire plate 411 is inclined towards the other top tire plate 411 from the end near the fixing part 31 to the end away from the fixing part 31. In this embodiment, the two top tire plates 411 are arranged at intervals to support both sides of the outer ring of the spare tire 200, thereby preventing the spare tire 200 from shaking and improving stability. It should be noted that, in another embodiment, the top tire part 41 is a rod provided on the top tire frame 4, and the outer ring of the spare tire 200 is supported by the end of the rod.

[0048] Furthermore, the top tire frame 4 is provided with a connecting hole 4a, and the top tire piece 411 is provided with a mating hole corresponding to the connecting hole 4a; the tire frame also includes a connecting bolt and a connecting nut, one end of the connecting bolt passing through the connecting hole 4a and the mating hole, and the connecting nut being screwed onto the connecting bolt, so that the tilt angle of the top tire piece 411 is adjustable. In this embodiment, by adjusting the tightness of the connecting nut on the connecting bolt, the tilt angle of the top tire piece 411 can be adjusted, thereby facilitating the top tire piece 411 to fit against the outer ring supporting the spare tire 200.

[0049] Furthermore, the shelf 2 is provided with a fixed tube 21, and the tire holder 3 is provided with a tube clamp 32 corresponding to the fixed tube 21. The tube clamp 32 is sleeved on the outer wall of the fixed tube 21 and fastened to the fixed tube 21 by a screw fastener, so that the tire holder 3 can rotate relative to the fixed tube 21 around its axial direction when the screw fastener is loosened. In this way, after loosening the screw fastener on the tube clamp 32, the spare tire 200 can be rotated towards the material rack 5, so that the user can easily take and put the spare tire 200, improving convenience. It should be noted that the tube clamp 32 is a split unit and is provided with a corresponding through hole for the screw fastener to be screwed and fastened to the fixed tube 21.

[0050] Furthermore, the fixing part 31 is a fixing plate 311, which is located on the side of the tire holder 3 away from the material rack 5 and has a fixing hole for threaded fasteners to pass through, so that the spare tire 200 can be fixed to the fixing plate 311. In this embodiment, the inner ring of the spare tire 200 is fixed to the fixing plate 311 by threaded fasteners, which is simple in structure and saves costs. It should be understood that in this embodiment, the aforementioned threaded fasteners include bolts and nuts, which will not be described in detail here. In another embodiment, the fixing part 31 is a strap provided on the tire holder 3, so as to fix the inner ring of the spare tire 200 by means of the strap.

[0051] Furthermore, the material rack 5 includes a main frame 52, fasteners 54, and two side frames 53. The main frame 52 is disposed on the shelf 2 and located on the side of the fixed frame 3 away from the top frame 4. The two side frames 53 are respectively installed at both ends of the main frame 52, and at least one side frame 53 can move away from the other side frame 53, so that the distance between the two side frames 53 can be adjusted. The fasteners 54 are disposed between each side frame 53 and the main frame 52, and are used to restrict the movement of the side frames 53 relative to the main frame 52 after the distance between the two side frames 53 is adjusted to a preset distance. In this embodiment, the distance between the two side frames 53 can be adjusted, so that the overall length of the material rack 5 can be adjusted accordingly, improving flexibility.

[0052] Furthermore, the main frame 52 and the two side frames 53 are provided with multiple fastening holes 5a along the arrangement direction of the two side frames 53, and the loading part 51 is a loading hole 51a provided on the main frame 52 and the side frames 53; the fastener 54 includes multiple sets of fastening bolts and fastening nuts, the fastening bolts are inserted into the fastening holes 5a of the main frame 52 and the fastening nuts are screwed into the fastening bolts, so that the distance between the two side frames 53 is adjustable. In this embodiment, the distance between the two side frames 53 can be adjusted accordingly through the cooperation of the fastening bolts, fastening nuts and fastening holes 5a, and the structure is simple and reliable. Furthermore, materials can be fixed on the material rack 5 by cooperating with external screws or steel cables in the loading holes 51a. In another embodiment, the loading part 51 is a strap provided on the material rack 5 for binding the materials.

[0053] It should be noted that, in this embodiment, the main frame 52 includes a main plate 521 and two extension plates 522. The two extension plates 522 are respectively spaced apart at both ends of the main plate 521 in a direction away from the fixing frame 3. Both the main plate 521 and the extension plates 522 are provided with fastening holes 5a. In addition, the two side frames 53 are similar to the main frame 52. And the end of each side frame 53 away from the other side frame 53 is bent and extends toward the fixing part 31.

[0054] Additionally, the main body plate 521 of the main frame 52 has an installation sleeve 55 on the side away from the extension plate 522. The shelf 2 includes a mating sleeve 23, a stop sleeve 24, and a screw connector. The mating sleeve 23 extends away from the fixed frame 3 and has multiple locking holes at intervals. The stop sleeve 24 has a positioning hole corresponding to the locking hole, and the installation sleeve 55 has a limiting hole corresponding to the locking hole. The installation sleeve 55 is fitted around the outer periphery of the stop sleeve 24, with one end of the stop sleeve 24 extending into the mating sleeve 23 and the other end extending out of the installation sleeve 55. The end extending out of the installation sleeve 55 also has a limiting handle 25. In this way, the stop sleeve 24 and the installation sleeve 55 can be fixed to the mating sleeve 23 by screw connectors passing through the locking hole, positioning hole, and limiting hole, and the distance between the installation sleeve 55 and the fixed frame 3 can be adjusted, thereby making the distance between the material shelf 5 and the fixed frame 3 adjustable.

[0055] Furthermore, in this embodiment, a license plate sleeve 56 is provided on the side of the main body plate 521 away from the extension plate 522. The license plate sleeve 56 extends in a direction away from the shelf 2 and has corresponding mounting holes. The trailer extension frame structure 100 also includes a license plate frame 6, which is used to fix the license plate. An extension tube 61 is provided for the license plate sleeve 56, extending into the license plate sleeve 56 and having through holes corresponding to the mounting holes, so as to fix the license plate frame 6 to the license plate sleeve 56 by means of screws. It should be noted that the mounting frame 1 has multiple holes and corresponding metal bushings and rubber shock-absorbing pads for fixing to the vehicle body.

[0056] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A rear extension frame structure for a towed caravan, characterized in that, It includes: The bracket includes a mounting bracket and a shelf connected together, wherein the end of the mounting bracket away from the shelf is used to be mounted on the vehicle body, so that the shelf can extend out of the vehicle body; A tire holder includes a fixed tire holder and a top tire holder, the fixed tire holder and the top tire holder being installed at a distance from each other on a shelf. The fixed tire holder has a fixing part, which is spaced apart from the shelf and used to fix the inner ring of the spare tire. The top tire holder has a top tire part, which is spaced apart from the fixing part on the side near the shelf and used to support the outer ring of the spare tire. The distance between the top tire part and the shelf is adjustable. A material rack is installed on the shelf and located on the side of the fixed frame away from the top frame, and is provided with a loading part for loading materials; The top tire frame includes a support frame, a top tire screw, and two adjusting nuts. The support frame is fixed to the shelf and is spaced apart on the side of the fixed part near the shelf, and has a stop hole facing the fixed part. One end of the top tire screw passes through the stop hole, and the other end points to the fixed part. The two adjusting nuts are screwed onto the top tire screw and are located at both ends of the stop hole, respectively. The top tire part is located at the end of the top tire screw pointing to the fixed part. The shelf is provided with a fixed tube, and the fixed frame is provided with a tube clamp corresponding to the fixed tube. The tube clamp is sleeved on the outer wall of the fixed tube and fastened to the fixed tube by a screw fastener, so that the fixed frame can rotate relative to the fixed tube around the axis of the fixed tube when the screw fastener is loosened. The material rack includes a main frame, fasteners, and two side frames. The main frame is mounted on the shelf and is located on the side of the fixed frame away from the top frame. The two side frames are respectively installed at both ends of the main frame, and at least one side frame can move away from the other side frame, so that the distance between the two side frames can be adjusted. The fasteners are located between each side frame and the main frame to restrict the movement of the side frame relative to the main frame after the distance between the two side frames is adjusted to a preset distance. The shelf is equipped with a connecting tube, and the connecting tube has pin holes along its radial direction; the support frame is equipped with a mounting groove, which is notched to allow the connecting tube to pass through, and the bottom of the mounting groove has an insertion hole corresponding to the pin hole; the top frame also includes pins, which are inserted into the insertion hole and the pin hole to fix the support frame to the shelf. The connecting tube has multiple pin holes spaced apart along the direction away from the fixed frame, so as to adjust the position of the support frame on the connecting tube, thereby adjusting the distance between the support frame and the fixed frame.

2. The trailer caravan rear extension frame structure according to claim 1, characterized in that, The top tire frame also includes a limiting tube, the inner cavity of which is polygonal and is movably sleeved along its axial direction at one end of the top tire screw where the top tire part is located, and its side wall is provided with an avoidance opening communicating with the inner cavity. The portion of the top screw located in the inner cavity is polygonal, and one of the two adjusting nuts is a wing nut. The wing nut is located at the end of the stop hole near the fixing part and is placed in the inner cavity of the limiting tube, with its wing-shaped handle extending out of the clearance opening.

3. The trailer caravan rear extension frame structure according to claim 1, characterized in that, The support frame is provided with a guide channel along the direction away from the stop hole. The guide channel is polygonal and its size is larger than that of the guide hole. One of the two adjusting nuts is a limiting screw sleeve, which is located inside the guide channel and its outer wall is polygonal in shape corresponding to the guide channel.

4. The trailer caravan rear extension frame structure according to claim 1, characterized in that, The top frame is provided in two parts, and the two top frames are spaced apart on both sides of the fixing part; The top tire portion is a top tire piece, which is installed on the corresponding top tire frame, and each top tire piece is inclined from one end near the fixed part to the end away from the fixed part toward the other top tire piece.

5. The trailer caravan rear extension frame structure according to claim 4, characterized in that, The top tire frame is provided with a connecting hole, and the top tire piece is provided with a mating hole corresponding to the connecting hole; The tire frame also includes connecting bolts and connecting nuts. One end of the connecting bolt passes through the connecting hole and the mating hole, and the connecting nut is screwed onto the connecting bolt, so that the tilt angle of the top tire piece is adjustable.

6. The trailer caravan rear extension frame structure according to claim 1, characterized in that, The fixing part is a fixing plate, which is located on the side of the tire fixing frame away from the material rack and has a fixing hole for threaded parts to pass through so as to fix the spare tire to the fixing plate.

7. The trailer caravan rear extension frame structure according to claim 1, characterized in that, The main frame and the two side frames are provided with a plurality of fastening holes along the arrangement direction of the two side frames, and the loading part is a loading hole provided on the main frame and the side frames; The fasteners include multiple sets of fastening bolts and fastening nuts. The fastening bolts are inserted into the fastening holes of the side frames of the main frame, and the fastening nuts are screwed onto the fastening bolts, so that the distance between the two side frames is adjustable.

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