Folding pet bed
By designing a folding pet bed, the articulated structure of the front chassis, rear chassis and enclosure frame is used to solve the problem of space occupied by fixed pet beds, achieving compact storage and comfortable use of pet beds, and satisfying the sleep of large pets need.
Patent Information
- Application Number
- CN202421027185.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-11
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-05-11
AI Technical Summary
Most of the existing pet beds are fixed, which occupy a large space and is inconvenient to move, making it difficult to meet the comfortable sleep needs of large pets such as dogs. At the same time, they are large in size and occupy space when not in use.
A folding pet bed is designed, through the folding connection between the front and rear chassis, combined with the articulated structure of the left and right chassis, forming a foldable rectangular shape, and using hinges and shaped structures to realize the bed body. Compact storage and provides spacious sleeping space when unfolded.
It realizes the size of the pet bed when not in use, making it easy to store and carry, and provides a comfortable sleeping space when in use, improving the convenience of use and space utilization efficiency.
Smart Images
Figure CN222236123U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of pet beds, and in particular relates to a foldable pet bed. Background Art
[0002] In modern pet care, it is particularly important to provide pets with a comfortable and convenient resting environment. Especially for pets like dogs, due to their large size, they need a spacious and comfortable sleeping space. However, with the increasing shortage of urban living space, how to meet the sleeping needs of dogs while effectively saving space has become a major challenge in the design of pet products.
[0003] Most existing pet beds are fixed, large in size, and occupy more indoor space. Although they can provide a certain degree of comfort, their bulky size and inconvenient mobility become a major problem when they are not in use or need to be moved.
[0004] Therefore, the inventor is committed to designing a pet bed to solve the above problems. Utility Model Content
[0005] The purpose of the utility model is to provide a foldable pet bed, which not only greatly reduces the volume of the pet bed when not in use, making it convenient to store and carry, but also provides a spacious and comfortable sleeping space for the pet when unfolded for use.
[0006] In order to achieve the above object, a technical solution adopted by the utility model is:
[0007] A foldable pet bed comprises a front base frame and a rear base frame, the front base frame and the rear base frame are arranged in parallel from front to back and are foldably connected, a rear end of the rear base frame is surrounded by a rear frame, the rear base frame is hinged to the rear frame, a left frame and a right frame are hinged to the left and right ends of the rear frame respectively, the front base frame and the rear base frame are located between the left frame and the right frame, the front base frame and the rear base frame are jointly supported by the left frame and the right frame, and bearings are provided on the front base frame and the rear base frame.
[0008] As an improvement of the foldable pet bed of the utility model, the bottom of the front base frame is folded and connected with the bottom of the rear base frame by hinges, the rear frame is in a U-shape, two connecting columns are arranged on the rear frame at intervals, a blocking frame is connected between the two connecting columns, and a blocking net is laid in the blocking frame.
[0009] As an improvement of the foldable pet bed of the utility model, the lower end of the rear frame is detachably connected to a fixing rod in a transverse direction, and a sleeve is provided on the hinged side of the rear bottom frame, and the sleeve is movably sleeved on the fixing rod.
[0010] As an improvement of the foldable pet bed of the utility model, support columns are vertically arranged at the left and right ends of the rear frame, and the hinged sides of the left frame and the right frame are hinged to the corresponding support columns through sleeves.
[0011] As an improvement of the foldable pet bed of the utility model, a plurality of supporting blocks are respectively provided at the lower ends of the left frame and the right frame, the front frame and the rear frame are located on the plurality of supporting blocks, and at least one supporting block is limitedly connected to the front frame or the rear frame.
[0012] As an improvement of the foldable pet bed of the utility model, the front base frame and the rear base frame are connected by connecting rods to form a frame shape, and the bearing member is a bed board, and the front base frame and the rear base frame respectively support the bed board.
[0013] In order to achieve the above object, another technical solution adopted by the utility model is:
[0014] A foldable pet bed comprises a front base frame and a rear base frame, the front base frame and the rear base frame are arranged in parallel from front to back and are foldably connected, a rear end of the rear base frame is surrounded by a rear frame, the rear base frame is hinged to the rear frame, a left frame and a right frame are hinged to the left and right ends of the rear frame respectively, the front base frame and the rear base frame are located between the left frame and the right frame, the front base frame and the rear base frame are jointly supported by the left frame and the right frame, and bearings are provided on the front base frame and the rear base frame.
[0015] As an improvement of the foldable pet bed of the utility model, the bottom of the front base frame is folded and connected with the bottom of the rear base frame by hinges, the rear frame is in a U-shape, two connecting columns are arranged on the rear frame at intervals, a blocking frame is connected between the two connecting columns, and a blocking net is laid in the blocking frame.
[0016] As an improvement of the foldable pet bed of the utility model, a fixing rod is transversely fixed to the lower end of the rear frame, and a sleeve is provided on the hinged side of the rear bottom frame, and the sleeve is movably sleeved on the fixing rod.
[0017] As an improvement of the foldable pet bed of the utility model, support columns are vertically arranged at the left and right ends of the rear frame, and the hinged sides of the left frame and the right frame are hinged to the corresponding support columns through sleeves.
[0018] As an improvement of the foldable pet bed of the utility model, a plurality of supporting blocks are respectively provided at the lower ends of the left frame and the right frame, the front frame and the rear frame are located on the plurality of supporting blocks, and at least one supporting block is limitedly connected to the front frame or the rear frame.
[0019] As an improvement of the foldable pet bed of the utility model, the front frame and the rear frame are arranged side by side and assembled to form a frame shape, and the bearing member is a bed cloth, and the edges of the bed cloth are folded and sleeved on the front frame and the rear frame.
[0020] As an improvement of the foldable pet bed of the utility model, the front base frame includes a front frame body and two front extension rods, and the two front extension rods are detachably connected to the two ends of the front frame body to form a U-shape.
[0021] As an improvement of the foldable pet bed of the utility model, the rear base frame includes a rear frame body and two rear extension rods, the two rear extension rods are detachably connected to the two ends of the rear frame body to form a U shape, and the two front extension rods are foldably connected to the two rear extension rods in a one-to-one correspondence.
[0022] As an improvement of the foldable pet bed of the utility model, the bottoms of the front extension rod and the rear extension rod are respectively vertically and elastically connected with a front positioning column and a rear positioning column, the disassembly end of the front extension rod is inserted into the front frame body and limitedly cooperates with the front positioning hole on the front frame body through the front positioning column, and the disassembly end of the rear extension rod is inserted into the rear frame body and limitedly cooperates with the rear positioning hole on the rear frame body through the rear positioning column.
[0023] Compared with the prior art, the foldable pet bed of the utility model utilizes a front base frame and a rear base frame to be foldably connected, and the front base frame, the left frame and the right frame are all hinged with the rear frame, so that the front base frame and the rear base frame with bearing parts, as well as the left frame and the right frame can be coordinated and folded toward one side of the rear frame, so that the entire bed body presents a regular rectangular shape after folding, which not only greatly reduces the volume of the pet bed when not in use, and is convenient for storage and carrying, but also provides a spacious and comfortable sleeping space for the dog when unfolded for use. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 is a three-dimensional diagram of a foldable pet bed according to a first embodiment of the utility model;
[0025] Figure 2 It is a three-dimensional exploded view of the foldable pet bed of the first embodiment of the utility model;
[0026] Figure 3 It is a three-dimensional enlarged view of the rear frame of the first embodiment of the utility model;
[0027] Figure 4 It is a three-dimensional enlarged view of the left peripheral frame of the first embodiment of the utility model;
[0028] Figure 5 is a three-dimensional diagram of the foldable pet bed of the first embodiment of the utility model from another perspective;
[0029] Figure 6 It is a three-dimensional exploded view of two base frames and two bed boards of the first embodiment of the utility model;
[0030] Figure 7 It is a three-dimensional enlarged view of the rear chassis of the first embodiment of the utility model;
[0031] Figure 8 It is a front view and a partial cross-sectional view of a foldable pet bed according to the first embodiment of the utility model;
[0032] Fig. 9 yes Figure 8 A partial cross-sectional enlarged view of FIG.
[0033] Fig.10 is a three-dimensional diagram of the foldable pet bed of the first embodiment of the utility model in a folded state;
[0034] Fig.11 is a three-dimensional diagram of a foldable pet bed according to a second embodiment of the present utility model;
[0035] Fig.12 is a three-dimensional diagram of the foldable pet bed of the second embodiment of the utility model without the bed cloth;
[0036] Fig.13 This is a three-dimensional exploded view of the foldable pet bed of the second embodiment of the utility model without the bed cloth;
[0037] Fig.14 It is a three-dimensional view of the foldable pet bed of the second embodiment of the utility model after the bed cloth is removed from another perspective;
[0038] Fig.15 It is a three-dimensional exploded view of the front bottom frame, the rear bottom frame and the bed cloth of the second embodiment of the utility model;
[0039] Fig.16 It is a three-dimensional exploded enlarged view of the rear chassis of the second embodiment of the utility model;
[0040] Fig.17 It is a three-dimensional view of the foldable pet bed according to the second embodiment of the utility model in a folded state.
[0041] Illustration Description:
[0042] 1. Rear frame; 11. Connecting column; 111. Decorative piece; 12. Support column; 13. Blocking frame; 131. Blocking net; 14. Fixing rod; 2. Left frame; 21. Sleeve; 22. Supporting block; 221. Limiting column; 3. Right frame; 4. Rear base frame; 41. Sleeve; 42. Limiting hole; 43. Rear bearing bar; 44. Rear frame; 441. Rear positioning hole; 45. Rear extension rod; 451. Rear positioning column; 5. Front base frame; 51. Front bearing bar; 52. Front frame; 521. Front positioning hole; 53. Front extension rod; 531. Front positioning column; 6. Bed board; 7. Hinge; 8. Bed cloth; 81. Folding part. DETAILED DESCRIPTION
[0043] The following is a detailed explanation of the implementation of the present invention in conjunction with the accompanying drawings. The accompanying drawings are for reference and illustration only and do not constitute a limitation on the scope of patent protection of the present invention.
[0044] Embodiment 1
[0045] Reference Figures 1 to 10 , is a foldable pet bed of the first embodiment of the utility model, comprising a front base frame 5, a rear base frame 4, a rear surrounding frame 1, a left surrounding frame 2 and a right surrounding frame 3, the front base frame 5 and the rear base frame 4 are arranged in parallel from front to back and are foldably connected, the rear surrounding frame 1 is surrounded by the rear end of the rear base frame 4, the rear base frame 4 is hinged to the rear surrounding frame 1, the left surrounding frame 2 and the right surrounding frame 3 are hinged to the left and right ends of the rear surrounding frame 1 respectively, the front base frame 5 and the rear base frame 4 are both located between the left surrounding frame 2 and the right surrounding frame 3, the front base frame 5 and the rear base frame 4 are jointly supported by the left surrounding frame 2 and the right surrounding frame 3, and the front base frame 5 and the rear base frame 4 are provided with bearing members.
[0046] Reference Figure 2 and Figure 3 The rear frame 1 is generally in the shape of a U and is connected by a plurality of connecting rods. Two connecting columns 11 are arranged at intervals in the middle of the rear frame 1. A frame-shaped baffle 13 is connected between the two connecting columns 11. A blocking net 131 is laid in the baffle 13. The edge of the blocking net 131 is connected to the baffle 13. In order to make the connection between the baffle 13 and the connecting column 11 more firmly, two spherical decorative pieces 111 are arranged at intervals on each connecting column 11. The four corners of the baffle 13 are respectively arranged on the four decorative pieces 111. The blocking net 131 can prevent the pet from rolling off the bed. The left and right ends of the rear frame 1 are respectively provided with cylindrical support columns 12 vertically. The lower end of the rear frame 1 is detachably connected to a cylindrical fixing rod 14 transversely by screws.
[0047] Reference Figure 2 , Figure 4 , Figure 5 , Figure 8 and Fig. 9, the left enclosure 2 is generally in the shape of a Chinese character 'Mu' (eye). The front end of the left enclosure 2 is its free end, and the rear end is its hinged end. Two sleeves 21 are provided at intervals on the hinged side of the left enclosure 2. Both of the two sleeves 21 are sleeved on the support column 12 on the left side of the rear enclosure 1, so that the left enclosure 2 is hinged to the left end of the rear enclosure 1. A plurality of supporting blocks 22 are provided at the lower end of the left enclosure 2. The plurality of supporting blocks 22 are perpendicular to the left enclosure 2 and are located below the front chassis 5 and the rear chassis 4. In this utility model, preferably two supporting blocks 22 are provided. The two supporting blocks 22 are arranged at intervals and extend towards the side of the right enclosure 3. A limiting post 221 is vertically provided on the rear supporting block 22.
[0048] Refer to Figure 2 and Figure 4 , the right enclosure 3 is also generally in the shape of a Chinese character 'Mu' (eye), and its structure is symmetrical to that of the left enclosure 2, that is: two sleeves 21 are also provided at intervals on the hinged side of the right enclosure 3. The two sleeves 21 on the right enclosure 3 are sleeved on the support column 12 on the right side of the rear enclosure 1, so that the right enclosure 3 is hinged to the rear enclosure 1. Two supporting blocks 22 are also provided at the lower end of the right enclosure 3. The two supporting blocks 22 are arranged at intervals and extend towards the side of the left enclosure 2. A limiting post 221 is also vertically provided on the rear supporting block 22. The supporting blocks 22 on the left enclosure 2 and the supporting blocks 22 on the right enclosure 3 are symmetrically arranged, so that all the supporting blocks 22 can normally support the front chassis 5 and the rear chassis 4.
[0049] Refer to Figures 5 to 9 , the rear chassis 4 is formed into a frame shape by connecting rods. Two rear bearing bars 43 are provided at intervals in the middle of the rear chassis 4 to form a shape like a Chinese character 'Mu' (eye). Two sleeves 41 are fixedly provided at intervals on the rear side of the rear chassis 4. The two sleeves 41 are movably sleeved on the fixed rod 14 of the rear enclosure 1, so that the rear chassis 4 is hinged to the rear enclosure 1. A limiting hole 42 is respectively provided at the bottom of the left and right ends of the rear chassis 4. The limiting hole 42 is in limiting cooperation with the limiting post 221 to prevent the rear chassis 4 from shifting.
[0050] Refer to Figure 5 and Figure 6 , the front chassis 5 is also formed into a frame shape by connecting rods. Two front bearing bars 51 are provided at intervals in the middle of the front chassis 5 to form a shape like a Chinese character 'Mu' (eye). The bottom of the front chassis 5 and the bottom of the left and right ends of the rear chassis 4 are respectively connected by hinges 7 in a folding manner, so that the front chassis 5 can be folded with the rear chassis 4.
[0051] Refer to Figure 5 and Figure 6 , the bearing member in this embodiment is specifically the bed board 6. The number of the bed boards 6 in this embodiment is specifically two. One bed board 6 is installed on the front chassis 5 and is supported by the two front bearing bars 51 on the front chassis 5, and the other bed board 6 is installed on the rear chassis 4 and is supported by the two rear bearing bars 43 on the rear chassis 4.
[0052] Refer to Figures 1 to 10 The method of using the foldable pet bed of this embodiment is as follows:
[0053] When the pet bed needs to be folded, the user directly pulls up and pushes the front bottom frame 5 inwards to disengage the limiting column 221 on the supporting block 22 from the limiting hole 42 at the bottom of the rear bottom frame 5, and the rear bottom frame 4 and the bed board 6 at the rear end rotate backwards together around the fixing rod 14 on the rear frame 1. At this time, the V-opening formed between the front bottom frame 5 and the rear bottom frame 4 faces downward, and the front bottom frame 5 is further pushed to fold the front bottom frame 5 and the rear bottom frame 4. At this time, the two bed boards 6 are also in a folded state, and finally the left frame 2 and the right frame 3 are pushed inwards respectively to rotate the left frame 2 and the right frame 3 by 90 degrees, and the left frame 2 and the right frame 3 are folded. Finally, the entire pet bed can be formed into a long strip of folded state (such as Fig.10 shown);
[0054] When it is necessary to unfold and use it, the user rotates the left and right frames 2 and 3 in the opposite direction and then pulls the front frame 5 outwards. At this time, the rear frame 4 is reversed around the fixing rod 14 on the rear frame 1 (the V-shaped opening formed by the front frame 5 and the rear frame 4 faces downward) until the front frame 5 and the rear frame 4 are in the unfolded state. On the one hand, the rear frame 4 is supported on the supporting blocks 22 at the rear ends of the left and right frames 2 and the front frame 5 is supported on the supporting blocks 22 at the front ends of the left and right frames 3. On the other hand, the limiting posts 221 on the left frame 2 and the limiting posts 221 on the right frame 3 are respectively inserted into the two limiting holes 42 on the rear frame 4, so that the rear frame 4 is limitedly connected to the left frame 2. The pet bed is unfolded and can be used normally for the pet (such as Figure 1 shown).
[0055] Embodiment 2
[0056] Reference Figures 11 to 17 , is the second embodiment of the utility model. The difference between this embodiment and the first embodiment is that: in this embodiment, the structure of the front base frame 5, the structure of the rear base frame 4 and the bearing member are different from those of the first embodiment. The bearing member of this embodiment is specifically a bed cloth 8. The front base frame 5 and the rear base frame 4 of this embodiment are both in a U-shape and are detachable structures. The front base frame 5 and the rear base frame 4 are arranged side by side and assembled to form a frame shape.
[0057] Reference Figures 13 to 16 In this embodiment, the front base frame 5 includes a front frame body 52 and two front extension rods 53. The front frame body 52 is in a U-shape. A front positioning hole 521 is respectively provided at the bottom of both ends of the front frame body 52. A front positioning column 531 is vertically provided at the bottom of the disassembly end (i.e., the front end) of each front extension rod 53. The front positioning column 531 is elastically connected to the corresponding front extension rod 53 through a spring. The disassembly end of the front extension rod 53 is inserted into the front frame body 52 and is limitedly matched with the front positioning hole 521 on the front frame body 52 through the front positioning column 531.
[0058] Reference Figures 13 to 16 The rear bottom frame 4 in this embodiment includes a rear frame body 44 and two rear extension rods 45. The rear frame body 44 is in a U-shape. A rear positioning hole 441 is respectively provided at the bottom of the left and right ends of the rear frame body 44. A rear positioning column 451 is vertically provided at the bottom of the disassembly end (i.e., the rear end) of each extension rod 45. The rear positioning column 451 is elastically connected to the corresponding rear extension rod 45 through a spring. The disassembly end of the rear extension rod 45 is inserted into the rear frame body 44 and limitedly cooperates with the rear positioning hole 441 on the rear frame body 44 through the rear positioning column 451. Two sleeves 41 are spaced apart on the rear side surface of the rear frame body 44. The two sleeves 41 are sleeved on the rear frame 1, so that the rear frame body 44 is hinged with the rear frame 1, the bottom of the front extension rod 53 at the left end is folded and connected with the bottom of the rear extension rod 45 at the left end through a hinge 7, and the bottom of the front extension rod 53 at the right end is folded and connected with the bottom of the rear extension rod 45 at the left end through a hinge 7, so that the front bottom frame 5 can be folded downward, and each rear extension rod 45 is also provided with a limiting hole 42 at the front end bottom. The limiting holes 42 on the two rear extension rods can be limitedly matched with the limiting columns 221 on the left frame 2 and the right frame 3 in a one-to-one correspondence. The edges of the bed cloth 8 are folded downward to form a folding portion 81 and are sleeved on the front bottom frame 5 and the rear bottom frame 4 (such as Fig.11 As shown), a mattress is formed for pets to rest. Other structures are the same as those in the first embodiment and will not be elaborated here.
[0059] The folding of the foldable pet bed of this embodiment (such as Fig.17 as shown) method and expansion (as shown Fig.11 The method is the same as that of the first embodiment and will not be elaborated here. When the user needs to remove the bed sheet 8 for cleaning, the user needs to first remove the screws at both ends of the fixing rod 14 with a screwdriver, and then remove the fixing rod 14 and the bed sheet 8, the front base frame 5 and the rear base frame 4 on the fixing rod 14. Remove the fixing rod 14, manually press the rear positioning column 451 and the front positioning column 531 at the left end, and then remove the front extension rod 53 and the rear extension rod 45 connected together by the hinge 7 at the left end, and manually press the right end. By removing the rear positioning column 451 and the front positioning column 531, the front extension rod 53 and the rear extension rod 45 connected together at the right end by another hinge 7 can be removed, and finally the front frame 52 and the rear frame 44 are pulled out, and the bed cloth 8 can be removed. After cleaning, the front frame 52 and the rear frame 44 are put on in sequence, and then the two front extension rods 53 and the rear extension rods 45 connected together by the hinges 7 are installed, and the bed cloth 8 can be installed on the front base frame 5 and the rear base frame 4, and finally the fixing rod 14 is installed.
[0060] The foldable pet bed of the utility model realizes the folding and storage function of the bed body through ingenious mechanical structure and material selection. Specifically, the left and right side frames of the pet bed are made of light and strong materials, which can be folded toward the rear side panels to form a compact structure. The mattress part is composed of two folding bottom frames, which can not only be folded separately, but also folded in coordination with the rear side frames, so that the entire bed body presents a regular rectangular shape after folding.
[0061] The foldable pet bed of the utility model not only greatly reduces the volume of the pet bed when not in use, making it convenient to store and carry, but also provides a spacious and comfortable sleeping space for the dog when unfolded. In addition, by optimizing the folding structure and material selection, the stability and durability of the foldable pet bed during folding and unfolding are ensured, so that it can withstand the wear and impact in daily use. This foldable pet bed not only solves the problem of space occupation of traditional pet beds, but also improves the convenience and comfort of use through clever design, providing pet owners with a better pet care experience.
[0062] The above disclosure is only a preferred embodiment of the present invention, which cannot be used to limit the scope of protection of the present invention. Therefore, equivalent changes made within the scope of the patent application of the present invention are still within the scope covered by the present invention.
Claims
1. A foldable pet bed, characterized in that: The invention comprises a front base frame and a rear base frame, which are arranged in parallel from front to back and are folded and connected with each other, a rear frame is arranged around the rear end of the rear base frame, the rear base frame is hinged to the rear frame, a left frame and a right frame are hinged at the left and right ends of the rear frame respectively, the front base frame and the rear base frame are located between the left frame and the right frame, the front base frame and the rear base frame are jointly supported by the left frame and the right frame, and bearing parts are arranged on the front base frame and the rear base frame.
2. The foldable pet bed according to claim 1, characterized in that: The bottom of the front frame is folded and connected with the bottom of the rear frame by hinges. The rear frame is in a U-shape. Two connecting columns are arranged on the rear frame at intervals. A blocking frame is connected between the two connecting columns. A blocking net is laid in the blocking frame.
3. The foldable pet bed according to claim 1, characterized in that: The lower end of the rear frame is detachably connected with a fixing rod in a transverse direction, and a sleeve is provided on the hinged side of the rear bottom frame, and the sleeve is movably sleeved on the fixing rod.
4. The foldable pet bed according to claim 1, characterized in that: Support columns are vertically arranged at the left and right ends of the rear frame, and the hinged sides of the left frame and the right frame are hinged to the corresponding support columns through sleeves.
5. The foldable pet bed according to claim 1, characterized in that: A plurality of supporting blocks are respectively provided at the lower ends of the left frame and the right frame, the front frame and the rear frame are located on the plurality of supporting blocks, and at least one supporting block is limitedly connected to the front frame or the rear frame.
6. The foldable pet bed according to claim 1, characterized in that: The front bottom frame and the rear bottom frame are both connected by connecting rods to form a frame shape, and the bearing member is a bed board, which is supported on the front bottom frame and the rear bottom frame respectively.
7. The foldable pet bed according to claim 1, characterized in that: The front bottom frame and the rear bottom frame are arranged in parallel and assembled to form a frame shape. The bearing member is a bed sheet. The edges of the bed sheet are folded and sleeved on the front bottom frame and the rear bottom frame.
8. The foldable pet bed according to claim 7, characterized in that: The front chassis comprises a front frame body and two front extension rods, and the two front extension rods are detachably connected to the two ends of the front frame body to form a U-shape.
9. The foldable pet bed according to claim 8, characterized in that: The rear chassis comprises a rear frame body and two rear extension rods, the two rear extension rods are detachably connected to the two ends of the rear frame body to form a U-shape, and the two front extension rods are foldably connected to the two rear extension rods in a one-to-one correspondence.
10. The foldable pet bed according to claim 9, characterized in that: The bottoms of the front extension rod and the rear extension rod are respectively vertically and elastically connected with a front positioning column and a rear positioning column. The disassembly end of the front extension rod is inserted into the front frame body and limitedly cooperates with the front positioning hole on the front frame body through the front positioning column. The disassembly end of the rear extension rod is inserted into the rear frame body and limitedly cooperates with the rear positioning hole on the rear frame body through the rear positioning column.