CN114013551B - Small comfortable folding bicycle - Google Patents

Abstract

The invention discloses a compact and comfortable folding bicycle, which comprises a main support tube. The front end of the main support tube is provided with a single-fork front wheel steering mechanism. The rear end of the main support tube is provided with a seat tube. Seat cushion, the seat cushion is located above the main support tube, the seat tube is also provided with a rear wheel steering mechanism, and the rear wheel steering mechanism is located below the main support tube; the front wheel section and the rear wheel section of the main support tube are connected by a double hinge mechanism, so that The front and rear wheel sections can be folded into a "U"shape; the double hinge mechanism has a locking mechanism that selectively fixes the front and rear wheel sections. The connection of the double hinge mechanism and the setting of the single-fork front wheel steering mechanism make the folding more compact and occupy less space, and the hinge setting is simple in structure and does not protrude too much from the main support tube, improving the smoothness of the body; and , the handlebars, head pipes and pedals in the bicycle can all be set to be foldable, which further reduces the space occupied by folding and is convenient for transportation and storage.

Description

Small and comfortable folding bike

technical field

The invention relates to the technology in the field of bicycles, in particular to a compact and comfortable folding bicycle.

Background technique

For traditional bicycles, the front and rear wheels are on different planes or have a height difference after folding, so the body cannot be moved through the wheels, and manual handling is required; because the overall structure of the bicycle is large and heavy, the folded Bicycles are more difficult to carry.

Later, a folder was used in the middle of the main support tube of the frame to realize the half-fold function. Since the folder is generally larger than the main support tube of the frame, the folder will protrude as a whole, which will cause the overall appearance of the bicycle to be unsmooth and affect the aesthetics. ; There is also a rotating shaft under the main support tube, and the rear wheel frame can be folded forward through the rotating shaft, but this structure needs to be folded before the seat tube is picked up before folding, and one side of the seat tube is easy to tilt downward , the folding process is complex and unfavorable for handling.

Therefore, it is necessary to study a new technical solution to solve the above problems.

Contents of the invention

In view of this, the present invention aims at the deficiencies in the prior art, and its main purpose is to provide a small and comfortable folding bicycle, the front wheel section and the rear wheel section of the support tube are connected through a double hinge mechanism and matched with a single fork front wheel steering mechanism The setting is folded into a "U" shape, which makes the folding more compact and takes up less space, and the hinge is set with a simple structure, which will not protrude too much from the main support tube, improving the smoothness of the body.

To achieve the above object, the present invention adopts the following technical solutions:

A compact and comfortable folding bicycle, comprising a main support tube, the front end of the main support tube is provided with a single-fork front wheel steering mechanism, the rear end of the main support tube is provided with a seat tube, and the top of the seat tube is provided with A retractable seat cushion, the seat cushion is located above the main support tube, and the seat tube is also provided with a rear wheel steering mechanism, and the rear wheel steering mechanism is located below the main support tube;

The front wheel section and the rear wheel section of the main support tube are connected by a double hinge mechanism, so that the front wheel section and the rear wheel section can be folded into a "U" shape; the double hinge mechanism has optional fixed front wheel sections and Locking mechanism for the rear wheel segment.

As a preferred solution, the double hinge mechanism includes a connecting pipe and two hinges arranged on one side of the connecting pipe, one end of the two hinges is connected to the connecting pipe, and the other ends of the two hinges are respectively connected to the front wheel segment, The rear wheel segment, the locking mechanism is arranged on the other side of the connecting pipe, the locking mechanism includes two racks and a rotation button engaged between the teeth of the two racks, and the rotation button drives the rack Move relative or opposite to rotationally lock the front and rear wheel segments.

As a preferred solution, the single-fork front wheel steering mechanism includes a head pipe, a handlebar assembly arranged at the upper end of the head pipe, and a front wheel assembly arranged at the lower end of the head pipe; the front wheel assembly includes a front wheel mounting frame and the front wheel, the front wheel mount is in the shape of a transverse "A", the front wheel mount includes a front wheel single fork and a suspension support tube with one end hinged to one end of the front wheel single fork, the front wheel The other end of the single fork is connected to the lower end of the head pipe, the front wheel is connected to the other end of the suspension support tube, and the other end of the suspension support tube is also provided with a braking system for braking. The front wheel single fork A first suspension shock absorber is sandwiched between the suspension support tube and the suspension support tube.

As a preferred solution, the handlebar assembly includes a telescopic faucet pipe arranged at the upper end of the head pipe, and a faucet hinged at the upper end of the faucet pipe. The two poles at the other end of the pole can rotate relative to the main pole, and the end of the poles away from the main pole is connected with a handle.

As a preferred solution, one end of the two struts close to the main pole can be selectively connected.

As a preferred solution, the rear wheel steering mechanism includes a rear wheel installation tube, the rear wheel installation tube is arranged on the seat tube, and the rear wheel installation tube is provided with a bicycle crank assembly, a rear wheel support link assembly and The rear wheel, the bicycle crank assembly and the rear wheel support link assembly are respectively located at the front side and the rear side of the seat tube.

As a preferred solution, the rear wheel support linkage assembly includes a seat stay and a seat stay, one end of the seat stay is hinged to the seat tube through a second suspension shock absorber, and the seat post of the seat stay is The other end is connected to one end of the chainstay, and the other end of the chainstay is hinged to the rear wheel installation pipe. A first support reinforcement is interposed between the chainstay and the chainstay, and the rear wheel is connected to the Chainstays.

As a preferred solution, the bicycle crank assembly includes a bicycle crank, two foldable pedals connected to the bicycle crank, a chain connecting the bicycle crank and the rear wheel, and the rear chainstay is also provided with a chain for shifting the speed of the chain. transmission.

As a preferred solution, the front end of the rear wheel installation tube is connected to the main support tube through a second support reinforcement, and both the first support reinforcement and the second support reinforcement are hollowed out.

As a preferred solution, the bottom of the seat tube is provided with telescopic traveling wheels.

Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, it can be known from the above technical solutions:

The main thing is that the front wheel section and the rear wheel section of the support tube are connected by a double hinge mechanism and combined with the setting of the single fork front wheel steering mechanism, and folded into a "U" shape, which makes the folding more compact and takes up less space. , the structure is simple, and the main support tube will not protrude too much, so as to improve the smoothness of the body;

Secondly, the front wheel mounting bracket is in the shape of a horizontal "A", and the front wheel single fork, suspension support tube, braking system, and first suspension shock absorber are integrally arranged, and the structure is compact, and the front wheel single fork The setting reduces the overall weight, and the setting of the first suspension shock absorber reduces the vibration of the body, making the ride more comfortable;

Furthermore, the faucet includes a main rod with one end hinged to the faucet pipe, and two rods connected to the other end of the main rod. The two rods can rotate relative to the main rod, and the end of the rod away from the main rod is connected There are handles; the overall faucet can be adjusted to different angles and heights, adapting to the ergonomics of different people, and the pole can be rotated. When folded, the bicycle can be made more compact as a whole and occupy less space;

And, the bottom of the seat tube has a telescopic traveling wheel. When transporting, the traveling wheel is released downwards to touch the ground. On the one hand, it forms a support for the folded vehicle body, avoiding the downward inclination of one side of the seat tube. phenomenon, and at the same time facilitate the overall handling.

In order to more clearly illustrate the structural features and functions of the present invention, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Description of drawings

Fig. 1 is a three-dimensional schematic view (unfolded state) of a preferred embodiment of the present invention;

Fig. 2 is a schematic perspective view of another viewing angle (unfolded state) of a preferred embodiment of the present invention;

Fig. 3 is a top view (unfolded state) of a preferred embodiment of the present invention;

Fig. 4 is a schematic diagram of a double hinge mechanism of a preferred embodiment of the present invention;

Fig. 5 is a schematic diagram of another perspective of the double hinge mechanism of the preferred embodiment of the present invention;

Fig. 6 is a double hinge mechanism (unlocked state) of a preferred embodiment of the present invention;

Fig. 7 is the double hinge mechanism (locked state) of the preferred embodiment of the present invention;

Fig. 8 is the front wheel assembly of the preferred embodiment of the present invention (the front wheel moves up state);

Fig. 9 is the front wheel assembly of the preferred embodiment of the present invention (the front wheel moves down state);

Figure 10 is a front view of a preferred embodiment of the present invention (long arm operating state);

Figure 11 is a front view of a preferred embodiment of the present invention (short arm operating state);

Fig. 12 is a schematic diagram of a handlebar assembly of a preferred embodiment of the present invention;

Fig. 13 is a schematic diagram of the main rod hinge of a preferred embodiment of the present invention;

Figure 14 is a schematic diagram of the connection of two struts in a preferred embodiment of the present invention;

Fig. 15 is a schematic diagram of separation of two struts in a preferred embodiment of the present invention;

Fig. 16 is a schematic view of the rear wheel steering mechanism of a preferred embodiment of the present invention;

Figure 17 is a schematic perspective view of a preferred embodiment of the present invention (storage folded state, pedals are not folded);

Figure 18 is a perspective view of a preferred embodiment of the present invention (storage folded state, pedal folded);

Figure 19 is a top view of a preferred embodiment of the present invention (storage folded state);

Figure 20 is a side view (storage folded state) of a preferred embodiment of the present invention;

Fig. 21 is a schematic perspective view of a preferred embodiment of the present invention (promoting the folded state);

Fig. 22 is a schematic diagram of folding the head tube of a preferred embodiment of the present invention;

Fig. 23 is a schematic diagram of folded poles of a preferred embodiment of the present invention;

Fig. 24 is a schematic diagram of folding of the double hinge mechanism of a preferred embodiment of the present invention.

Explanation of the accompanying drawings:

10. Main support tube 11. Front wheel section

12. Rear wheel section 20. Single-fork front wheel steering mechanism

21. Head pipe 22. Handlebar assembly

221. Faucet pipe 222. Faucet

2221, main rod 2222, support rod

23. Front wheel assembly 231. Front wheel mounting frame

2311. Front wheel single fork 2312. Suspension support tube

2313. Brake system 2314. First suspension shock absorber

232. Front wheel 24. Lock nut

241. Preload spring

30. Seat tube 31. Seat cushion

40. Double hinge mechanism 41. Locking mechanism

411, rack 412, gear

413. Rotary button 414. Resetting elastic piece

42. Connecting pipe 43. Hinge

44. Locking mechanism protective cover

50. Rear wheel steering mechanism 51. Rear wheel installation pipe

511. Second support reinforcement 52. Bicycle crank assembly

521, bicycle crank 522, pedal

523. Chain 53. Rear wheel support link group

531, chainstay 532, chainstay

533. The second suspension shock absorber 534. The first support reinforcement

54. Rear wheel 60. Gear

70, walking wheel.

Detailed ways

Please refer to Figures 1 to 24, which show the specific structure of a preferred embodiment of the present invention, including a main support tube 10, the front end of the main support tube 10 is provided with a single-fork front wheel steering mechanism 20, The rear end of the main support tube 10 is provided with a seat tube 30, the top of the seat tube 30 is provided with a retractable seat cushion 31, the seat cushion 31 is located above the main support tube 10, and the seat tube 30 is also provided with There is a rear wheel steering mechanism 50, and the rear wheel steering mechanism 50 is located below the main support tube 10;

The front wheel section 11 and the rear wheel section 12 of the main support pipe 10 are joined by a double hinge mechanism 40, as shown in Figure 24, so that the front wheel section and the rear wheel section can be folded into a "U" shape, that is, the single The fork front wheel steering mechanism 20 is folded backward to be parallel or nearly parallel to the rear wheel steering mechanism 50, or the rear wheel steering mechanism 50 is folded forward to be parallel or nearly parallel to the single fork front wheel steering mechanism 20; the double hinge mechanism 40 There is a locking mechanism 41 that can selectively fix the front wheel segment 11 and the rear wheel segment 12 .

The present invention can be applied to travel tools, leisure travel, sports, competitions, etc.; the present invention can be applied to different types of bicycles (such as small folding bicycles, mountain bikes, road bicycles, etc.), electric bicycles; the bicycles of the present invention can be applied to different sizes , shape, the bicycle wheel of material (as 14,16,18,20,24,26 inches etc.); alloy, carbon graphite, titanium alloy, etc.); and different types and sizes of screws and nuts can be flexibly used for installation during assembly.

Specifically, the double hinge mechanism 40 includes a connecting pipe 42 and two hinges 43 arranged on one side of the connecting pipe 42, one end of the two hinges 43 is connected to the connecting pipe 42, and the other ends of the two hinges 43 are respectively connected to On the front wheel section 11 and the rear wheel section 12, the locking mechanism 41 is arranged on the other side of the connecting pipe 42, and the locking mechanism 41 includes two racks 411 and a tooth portion 412 engaged with the two racks 411 Between the rotation button 413, the rotation button 413 drives the rack 411 to move relatively or towards each other to rotationally lock the front wheel segment 11 and the rear wheel segment 12, and one rotation button 413 drives the two racks 411 to lock and unlock simultaneously The two hinges 43 have a simple structure; the locking mechanism 41 also includes two reset elastic members 414, and the reset force of the two reset elastic members 414 faces the locking direction of the two racks 411, so that the two hinges 43 are always in the Locked position to ensure safety; the main support tube 10 is also provided with a locking mechanism protection cover 44, which is used to prevent any accidental activation of the rotation button 413 and ensure the safe use of the bicycle; one main support tube 10 is matched with two hinges 43 , the bicycle is folded compactly, so that the main support tube 10 is folded into a "U" shape, and the front and rear wheels move in parallel and move smoothly during operation; limit.

The single-fork front wheel steering mechanism 20 includes a head pipe 21, a handlebar assembly 22 arranged at the upper end of the head pipe 21, and a front wheel assembly 23 arranged at the lower end of the head pipe 21, wherein as shown in FIG. 22 , the head pipe 21 is foldable; the front wheel assembly 23 includes a front wheel mounting frame 231 and a front wheel 232, the front wheel mounting frame 231 is in the shape of a transverse "A", and the front wheel mounting frame 231 includes a front wheel The single fork 2311 and one end are hinged to the suspension support pipe 2312 at one end of the front wheel single fork 2311, the other end of the front wheel single fork 2311 is connected to the lower end of the head pipe 21, and the front wheel is connected to the suspension support pipe 2312 At the other end, the other end of the suspension support pipe 2312 is also provided with a brake system 2313 for braking. The brake system 2313 can adopt different types of brake system mechanisms (such as wiring breaker discs, hydraulic breaker discs, etc.), so A first suspension shock absorber 2314 is sandwiched between the front wheel single fork 2311 and the suspension support pipe 2312 (the first suspension shock absorber 2314 can be a spring shock absorber, a hydraulic shock absorber, a pneumatic shock absorber , PU shock absorbers, etc.). The design of a main support tube 10 can help reduce the weight of the bicycle, and the front wheel adopts the design of the front wheel single fork 2311 to further reduce the weight of the bicycle; the setting of the first suspension shock absorber 2314 makes riding more comfortable.

The handlebar assembly 22 includes a tap tube 221 telescopically arranged on the upper end of the head tube 21, and a tap 222 hinged on the upper end of the tap tube 221. The tap 222 includes a main rod 2221 with one end hinged on the tap tube 221, a connecting Two poles 2222 at the other end of the main pole 2221, the two poles 2222 can rotate relative to the main pole 2221 through various mechanisms, the end of the poles 2222 away from the main pole 2221 is connected with a handle, the main pole 2221 A locking part is arranged at the hinge, and the locking part is a lock nut 24. The locking head of the lock nut 24 is butterfly-shaped, which is convenient for people to manually lock or unlock. The lock nut 24 has a preload The spring 241 makes the installation more firm, and the locking member can also adopt other locking methods, which are not limited to this embodiment. The main rod 2221 is hinged to the setting of the faucet tube 221, and the height of the faucet 222 can be adjusted up and down to adapt to the ergonomics of different people. The material and shape of the main rod 2221 are not limited thereto.

The rear wheel steering mechanism 50 includes a rear wheel installation tube 51, the rear wheel installation tube 51 is arranged on the seat tube 30, and the rear wheel installation tube 51 is provided with a bicycle crank assembly 52, a rear wheel support link assembly 53 and the rear wheel 54, the bicycle crank assembly 52 and the rear wheel support link assembly 53 are respectively located at the front side and the rear side of the seat tube 30;

The rear wheel support link assembly 53 includes a seat stay 531 and a seat stay 532, and one end of the seat stay 531 passes through a second suspension shock absorber 533 (the second suspension shock absorber 533 can be a spring shock absorber, hydraulic shock absorber, pneumatic shock absorber, PU shock absorber, etc.) are hinged to the seat tube 30, and the other end of the chainstay 531 is connected to one end of the chainstay 532, and the chainstay 532 The other end is hinged to the rear wheel mounting pipe 51; the rear chainstay 532 is L-shaped, the rear chainstay 531 is connected to the short end of the chainstay 532, and the rear wheel 54 is connected to the short end of the chainstay 532. the junction of the side and the long side;

The bicycle crank assembly 52 includes a bicycle crank 521, two foldable pedals 522 connected to the bicycle crank 521, a chain 523 connecting the bicycle crank 521 and the rear wheel 54, and the rear chainstay 532 is also provided with a The speed changer of chain 523 speed changes. The main support pipe 10, the faucet pipe 221, the two poles 2222, and the pedal 522 can be arranged in a foldable manner to minimize the occupied storage space. Since the chain 523, the bicycle crank assembly 52, and the rear wheel 54 form an assembly unit, which does not involve the rotation of the rear wheel 54, the chain 523 is not easy to fall off during the folding process.

Preferably, a first support reinforcement 534 is interposed between the rear upper fork 531 and the rear chain fork 532, and the rear wheel 54 is connected to the rear chain fork 532. The front end of the rear wheel installation pipe 51 is supported by a second support. The reinforcing member 511 is connected to the main support pipe 10, and the first supporting reinforcing member 534 and the second supporting reinforcing member 511 are both hollowed out, which helps to reduce the weight of the bicycle;

And, the two poles 2222 are connected to the main pole 2221 through the end faces of the gears 60, and the two gears 60 can mesh with each other (to ensure that the poles 2222 are not easy to slip during rotation). When one pole 2222 rotates, the other pole 2222 is also relatively rotated to make the folding process faster and smoother. The two poles 2222 can also be connected to the main pole 2221 using other structures, not limited to this embodiment; the main pole 2221 and the two poles 2222 form a "Y" shape, or the two poles 2222 are arranged opposite to each other in a "Y" shape; one end of the two poles 2222 close to the main pole 2221 can be selectively connected (for example, one is provided with an external thread, and the other is provided with an internal thread The screw sleeve, the screw sleeve is adapted to the external thread, which is convenient for rotation locking and unlocking; one of them can be provided with a buckle, and the other can be provided with a button hole, and the two poles 2222 are fastened and connected);

In addition, the bottom of the seat tube 30 has a telescopic traveling wheel 70. When riding, the traveling wheel 70 can be adjusted upwards without touching the ground. When being folded and pushed, the traveling wheel 70 can be adjusted downwards to contact the ground; There are one or two wheels of different sizes, and the wheels can rotate around the seat tube 30 or not; and the walking wheels 70 can be directly installed on the seat tube 30 by different mounting mechanisms to realize up and down expansion and contraction.

The design focus of the present invention is:

The main thing is that the front wheel section and the rear wheel section of the support tube are connected by a double hinge mechanism and combined with the setting of the single fork front wheel steering mechanism, and folded into a "U" shape, which makes the folding more compact and takes up less space. , the structure is simple, and the main support tube will not protrude too much, so as to improve the smoothness of the body;

Secondly, the front wheel mounting bracket is in the shape of a horizontal "A", and the front wheel single fork, suspension support tube, braking system, and first suspension shock absorber are integrally arranged, and the structure is compact, and the front wheel single fork The setting reduces the overall weight, and the setting of the first suspension shock absorber reduces the vibration of the body, making the ride more comfortable;

Furthermore, the faucet includes a main rod with one end hinged to the faucet pipe, and two rods connected to the other end of the main rod. The two rods can rotate relative to the main rod, and the end of the rod away from the main rod is connected There are handles; the overall faucet can be adjusted to different angles and heights, adapting to the ergonomics of different people, and the pole can be rotated. When folded, the bicycle can be made more compact as a whole and occupy less space;

And, the bottom of the seat tube has a telescopic traveling wheel. When transporting, the traveling wheel is released downwards to touch the ground. On the one hand, it forms a support for the folded vehicle body, avoiding the downward inclination of one side of the seat tube. phenomenon, and at the same time facilitate the overall handling.

The above descriptions are only preferred embodiments of the present invention, and do not limit the technical scope of the present invention in any way, so any minor modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention are still valid. It belongs to the scope of the technical solutions of the present invention.

Claims (9)

1. A small and comfortable folding bicycle comprises a main supporting pipe, wherein a single-fork front wheel steering mechanism is arranged at the front end of the main supporting pipe, a seat pipe is arranged at the rear end of the main supporting pipe, a telescopic seat cushion is arranged at the top of the seat pipe and is positioned above the main supporting pipe, a rear wheel steering mechanism is also arranged on the seat pipe and is positioned below the main supporting pipe; the method is characterized in that:

the front wheel section and the rear wheel section of the main supporting pipe are connected through a double-hinge mechanism, so that the front wheel section and the rear wheel section can be folded into a U shape; the double-hinge mechanism is provided with a locking mechanism which can selectively fix the front wheel section and the rear wheel section; the double-hinge mechanism comprises a connecting pipe and two hinges arranged on one side of the connecting pipe, one ends of the two hinges are connected to the connecting pipe, the other ends of the two hinges are connected to the front wheel section and the rear wheel section respectively, the locking mechanism is arranged on the other side of the connecting pipe and comprises two racks and a rotating button meshed between tooth parts of the two racks, and the rotating button drives the racks to move relatively or oppositely to lock the front wheel section and the rear wheel section with rotation.

2. The small and comfortable folding bicycle of claim 1, characterized in that: the single-fork front wheel steering mechanism comprises a head pipe, a handlebar assembly and a front wheel assembly, wherein the handlebar assembly is arranged at the upper end of the head pipe, and the front wheel assembly is arranged at the lower end of the head pipe; the front wheel subassembly is including front wheel mounting bracket and front wheel, the front wheel mounting bracket is horizontal "A" font, the front wheel mounting bracket articulates the suspension stay tube in the one end of front wheel single fork including front wheel single fork and one end, the other end of front wheel single fork is connected in head pipe lower extreme, the front wheel is connected in the other end of suspension stay tube, the other end of suspension stay tube still is provided with the braking system who is used for the brake, press from both sides between front wheel single fork and the suspension stay tube and be equipped with first suspension bumper shock absorber.

3. The small and comfortable folding bicycle of claim 2, wherein: the handlebar assembly comprises a faucet pipe which is telescopically arranged at the upper end of the head pipe and a faucet which is hinged at the upper end of the faucet pipe, the faucet comprises a main rod with one end hinged to the faucet pipe and two supporting rods connected to the other end of the main rod, the two supporting rods can rotate relative to the main rod, and one ends of the supporting rods, far away from the main rod, are connected with a handle.

4. The small and comfortable folding bicycle of claim 3, characterized in that: one end of the two branch rods close to the main rod can be selectively connected.

5. The small and comfortable folding bicycle of claim 1, wherein: the rear wheel steering mechanism comprises a rear wheel installation pipe, the rear wheel installation pipe is arranged on the seat pipe, the rear wheel installation pipe is provided with a bicycle crank component, a rear wheel supporting connecting rod component and a rear wheel, and the bicycle crank component and the rear wheel supporting connecting rod component are respectively located on the front side and the rear side of the seat pipe.

6. The small and comfortable folding bicycle of claim 5, characterized in that: the rear wheel support connecting rod assembly comprises a rear upper fork and a rear lower fork, one end of the rear upper fork is hinged to the seat tube through a second suspension shock absorber, the other end of the rear upper fork is connected with one end of the rear lower fork, the other end of the rear lower fork is hinged to the rear wheel mounting tube, a first support reinforcing piece is clamped between the rear upper fork and the rear lower fork, and the rear wheel is connected to the rear lower fork.

7. The small and comfortable folding bicycle of claim 6, characterized in that: the bicycle crank component comprises a bicycle crank, two foldable pedals connected to the bicycle crank, and a chain connected with the bicycle crank and a rear wheel, and the rear lower fork is further provided with a speed changer for changing speed of the chain.

8. The small and comfortable folding bicycle of claim 6, characterized in that: the front end of rear wheel installation pipe passes through the second and supports the reinforcement and connect the main tributary stay tube, first support reinforcement, second support reinforcement are the fretwork setting.

9. The small and comfortable folding bicycle of claim 1 or 5, wherein: the bottom of the seat tube is provided with a walking wheel which is arranged in a telescopic way.

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