A child balance car damping rear fork welding tool
By designing a welding fixture for the shock-absorbing rear fork of a children's balance bike, the problem of inaccurate workpiece positioning during the welding process was solved, achieving high welding quality and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HEBEI WELDINGJUE ROBOT TECHNOLOGY CO LTD
- Filing Date
- 2025-08-13
- Publication Date
- 2026-07-24
AI Technical Summary
In the welding process of the shock-absorbing rear fork of a children's balance bike, the clamping and positioning of the workpiece becomes a bottleneck restricting welding quality and work efficiency due to the limitations of the bent tube structure and welding position.
Design a welding fixture for the shock-absorbing rear fork of a children's balance bike, including a base, a bending tube positioning and clamping mechanism, a connecting seat positioning mechanism, a rear wheel axle lug positioning and clamping mechanism, and a flipping axle lug positioning mechanism. Through the cooperation of these mechanisms, the welding workpiece can be accurately positioned and reliably fixed.
It achieves precise positioning and reliable fixing of all components of the shock-absorbing rear fork of the children's balance bike, ensuring the quality of the welded products and improving work efficiency.
Smart Images
Figure CN224543601U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of bicycle production equipment, specifically a welding fixture for the shock-absorbing rear fork of a children's balance bike. Background Technology
[0002] A balance bike is a recreational and exercise tool designed specifically for young children, primarily used to develop their balance. It lacks pedals and a chain drive system; children propel themselves forward by pushing off the ground with their feet. To adapt to different road conditions and venues, reduce the risk of joint damage from vibrations and bumps, and improve the safety of balance bikes, manufacturers have recently developed shock-absorbing balance bikes. These bikes incorporate shock-absorbing components between the rear fork and the connecting frame. The compression and rebound of these components, achieved through the flipping motion of the rear fork, effectively protects children's joints.
[0003] As attached Figure 1 , Figure 2 As shown, a shock-absorbing rear fork component 1 for a children's balance bike includes two symmetrically arranged bent tubes 1-1, with a bending angle of θ. A flip-up axle lug 1-2, which mates with a connecting frame, is located at the front end of each bent tube, and a rear wheel axle lug 1-3, which mates with the rear wheel axle, is located at the rear end. The two bent tubes 1-1 are welded together via a connecting seat 1-4. A flip-up axle mounting hole 1-2-1 is provided on the flip-up axle lug 1-2, and a rear wheel axle mounting hole 1-3-1 is provided on the rear wheel axle lug 1-3. A center hole 1-4-1 for mounting the shock absorber is provided on the connecting seat 1-4. When welding the aforementioned shock-absorbing rear fork component 1 for the children's balance bike, the clamping and positioning of the workpiece becomes a bottleneck restricting welding quality and work efficiency due to the limitations of the bent tube structure and welding position. Therefore, the clamping and positioning fixture for the welded workpiece needs to be optimized. Utility Model Content
[0004] This utility model provides a welding fixture for the shock-absorbing rear fork of a children's balance bike. It aims to achieve precise positioning and reliable fixation of the welding workpiece through the cooperation of the base, the bending tube positioning and clamping mechanism, the connecting seat positioning mechanism, the rear wheel axle lug positioning and clamping mechanism, and the flipping axle lug positioning mechanism, thereby ensuring the quality of the welding products and improving work efficiency.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: A welding fixture for the shock-absorbing rear fork of a children's balance bike includes a base, a bending tube positioning and clamping mechanism, a connecting seat positioning mechanism, a rear wheel axle lug positioning and clamping mechanism, and a flipping axle lug positioning mechanism. The base includes a vertical plate and a bottom plate. The bottom plate consists of a horizontal surface and an inclined surface. The angle between the inclined surface and the horizontal surface matches the bending angle of the bending tube. One end of the horizontal surface is fixedly assembled to the vertical plate. The base is assembled to a rotation machine at the welding station via the vertical plate. Two symmetrical welding clearance grooves are provided on the horizontal surface of the bottom plate. The bending tube positioning and clamping mechanism and the rear wheel axle lug positioning and clamping mechanism are installed on the inclined surface of the bottom plate. The connecting seat positioning mechanism and the flipping axle lug positioning mechanism are arranged on the horizontal surface of the bottom plate, with the connecting seat positioning mechanism located between the two welding clearance grooves.
[0006] The aforementioned welding fixture for the shock-absorbing rear fork of a children's balance bike includes a bend positioning and clamping mechanism comprising a bend positioning block and a downward-pressing bend clamping pliers. The bend positioning block consists of two parts, left and right, each part having a bend positioning groove that matches the outer surface of the left and right bends. The downward-pressing bend clamping pliers are arranged on the symmetrical axis of the left and right parts of the bend positioning block, and the clamping head of the downward-pressing bend clamping pliers is a clamping block extending in the left and right direction.
[0007] The aforementioned welding fixture for the shock-absorbing rear fork of a children's balance bike includes a rear wheel axle lug positioning and clamping mechanism comprising two symmetrically arranged parts. Each part is equipped with a rear wheel axle lug positioning seat and a side-push type rear wheel axle lug positioning and clamping pliers. The rear wheel axle lug positioning seat has rear wheel axle lug positioning pins at both ends, and the rear wheel axle lug positioning pins match the rear wheel axle mounting holes on the rear wheel axle lugs. The side-push type rear wheel axle lug positioning and clamping pliers are symmetrically arranged, and the clamping head of the side-push type rear wheel axle lug positioning and clamping pliers has rear wheel axle lug positioning pin clearance holes.
[0008] The aforementioned welding fixture for the shock-absorbing rear fork of a children's balance bike includes a flip-shaft lug positioning mechanism comprising two symmetrically arranged parts. Each part contains a flip-shaft lug positioning seat and a side-push type flip-shaft lug positioning clamp. The left and right end faces of the flip-shaft lug positioning seat are provided with flip-shaft lug positioning holes, the diameter of which is smaller than the diameter of the flip-shaft mounting hole on the flip-shaft lug. The side-push type flip-shaft lug positioning clamps are arranged in two symmetrical sets, each set containing a positioning rod that moves in the left and right direction. The front end of the positioning rod can pass through the flip-shaft lug positioning hole of the flip-shaft lug positioning seat.
[0009] The aforementioned welding fixture for the shock-absorbing rear fork of a children's balance bike includes a connecting seat positioning mechanism comprising a connecting seat positioning block and a connecting seat positioning pin. The connecting seat positioning block is fixed to the base plate via a central positioning hole provided between the left and right welding portion clearance grooves on the base plate, and a positioning pin is installed on the upper end face of the connecting seat positioning block. The positioning pin matches the central hole on the connecting seat.
[0010] The aforementioned welding fixture for the shock-absorbing rear fork of a children's balance bike includes, on the base plate, adjustment holes for a flip-up axle lug positioning seat, a side-push flip-up axle lug positioning clamp, a bent tube positioning block, a rear wheel axle lug positioning seat, and a side-push rear wheel axle lug positioning clamp. The adjustment holes for the flip-up axle lug positioning seat and the side-push flip-up axle lug positioning clamp are longitudinally elongated holes arranged on the horizontal surface of the base plate; the adjustment hole for the bent tube positioning block is a transversely elongated hole arranged on the inclined surface of the base plate; and the adjustment holes for the rear wheel axle lug positioning seat and the side-push rear wheel axle lug positioning clamp are longitudinally elongated holes arranged on the inclined surface of the base plate.
[0011] This utility model provides a welding fixture for the shock-absorbing rear fork of a children's balance bike. It uses a bend tube positioning and clamping mechanism to position and clamp the left and right bend tubes, a connecting seat positioning mechanism to provide support and limit the connecting seat, a rear wheel axle lug positioning and clamping mechanism to position and clamp the rear wheel axle lugs on the two bend tubes, and a flipping axle lug positioning mechanism to position the flipping axle lugs on the two bend tubes. The base of this utility model is assembled with a vertical plate and a rotation machine at the welding station. During welding, the connecting seat and bend tube can be welded on one side manually or by a welding robot. Then, the welding station rotation machine rotates the base 180 degrees, allowing welding to be performed on the other side of the connecting seat and bend tube through two welding area clearance grooves arranged on the horizontal surface of the base plate, completing the full welding process. This invention also adjusts the relative positions of the various components of the welding fixture through adjustment holes on the base plate for the flip-type axle lug positioning seat, the side-push type flip-type axle lug positioning clamp, the bent pipe positioning block, the rear wheel axle lug positioning seat, and the side-push type rear wheel axle lug positioning clamp, to meet the welding requirements of workpieces of different sizes. Therefore, this invention achieves precise positioning and reliable fixing of the various components of the shock-absorbing rear fork of a children's balance bike, thus ensuring the quality of welded products and improving work efficiency. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of the shock-absorbing rear fork structure of a children's balance bike according to a specific embodiment of this utility model; Figure 2 yes Figure 1 K-direction view; Figure 3 This is a schematic diagram of the structure of this utility model; Figure 4 yes Figure 3 Enlarged view of the structure at point I; Figure 5 yes Figure 3 Enlarged view of the structure at point II; Figure 6 yes Figure 3 K-direction view; Figure 7 This is a schematic diagram of the base plate structure; Figure 8 This is a schematic diagram of the working state of this utility model.
[0013] Explanation of each label in the diagram: 1 is the shock-absorbing rear fork component of the children's balance bike, 1-1 is the bent tube, 1-2 is the flip axle lug, 1-2-1 is the flip axle mounting hole, 1-3 is the rear wheel axle lug, 1-3-1 is the rear wheel axle mounting hole, 1-4 is the connecting seat, and 1-4-1 is the center hole; 2 is the base, 2-1 is the upright plate, 2-2 is the bottom plate, S is the horizontal plane of the bottom plate, X is the inclined plane of the bottom plate, 2-3 is the adjustment hole for the flip shaft lug positioning seat, 2-4 is the adjustment hole for the side-push type flip shaft lug positioning clamp, 2-5 is the center positioning hole, 2-6 is the clearance groove for the welding part, 2-7 is the adjustment hole for the bent pipe positioning block, 2-8 is the adjustment hole for the rear wheel axle lug positioning seat, and 2-9 is the adjustment hole for the side-push type rear wheel axle lug positioning clamping clamp. 3 is the flip shaft lug positioning mechanism, 3-1 is the side-push type flip shaft lug positioning clamp, 3-1-1 is the positioning rod, 3-2 is the flip shaft lug positioning seat, and 3-2-1 is the flip shaft lug positioning hole; 4 is the connecting seat positioning mechanism, 4-1 is the connecting seat positioning block, and 4-2 is the connecting seat positioning pin; 5 is the pipe bending positioning and clamping mechanism, 5-1 is the downward pressing type pipe bending clamping pliers, and 5-2 is the pipe bending positioning block; 6 is the rear wheel axle trunnion positioning and clamping mechanism, 6-1 is the side-push type rear wheel axle trunnion positioning and clamping clamp, and 6-2 is the rear wheel axle trunnion positioning seat. Detailed Implementation
[0014] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0015] See Figure 1. Figure 2A shock-absorbing rear fork component 1 for a children's balance bike includes two symmetrically arranged bent tubes 1-1, with a bending angle of θ. A flip-shaft lug 1-2 that mates with a connecting frame is provided at the front end of the bent tube, and a rear wheel axle lug 1-3 that mates with the rear wheel axle is provided at the rear end. The two bent tubes 1-1 are welded together by a connecting seat 1-4. A flip-shaft mounting hole 1-2-1 is provided on the flip-shaft lug 1-2, and a rear wheel axle mounting hole 1-3-1 is provided on the rear wheel axle lug 1-3. A center hole 1-4-1 for installing the shock absorber is provided on the connecting seat 1-4.
[0016] See Figure 2 , Figure 3 , Figure 6 , Figure 7 In the Figure 1 In the welding process of the shock-absorbing rear fork component 1 of the children's balance bike shown, in order to achieve precise positioning and reliable fixing of the bent tube 1-1 and the connecting seat 1-4, ensure the quality of the welded product, and improve work efficiency, this utility model provides a welding fixture for the shock-absorbing rear fork of a children's balance bike. It includes a base 2, a bent tube positioning and clamping mechanism 5, a connecting seat positioning mechanism 4, a rear wheel axle lug positioning and clamping mechanism 6, and a flipping axle lug positioning mechanism 3. The base 2 includes a vertical plate 2-1 and a bottom plate 2-2. The bottom plate 2-2 consists of a horizontal surface S and an inclined surface X. One end of the horizontal surface S is fixedly assembled to the vertical plate 2-1. The base 2 is assembled to the indexing machine at the welding station via the vertical plate 2-1. The inclined surface X... The bend angle θ of the bend 1-1 is matched with the horizontal plane S of the base plate. Two symmetrical welding part avoidance grooves 2-6 are provided on the horizontal plane S of the base plate. The bend positioning and clamping mechanism 5 and the rear wheel axle lug positioning and clamping mechanism 6 are installed on the inclined plane X of the base plate. The rear wheel axle lug positioning and clamping mechanism 6 includes two symmetrically arranged parts. The central axis of the bend positioning and clamping mechanism 5 is located on the left and right symmetrical planes of the rear wheel axle lug positioning and clamping mechanism 6. The connecting seat positioning mechanism 4 and the flipping axle lug positioning mechanism 3 are arranged on the horizontal plane S of the base plate. The flipping axle lug positioning mechanism 3 includes two symmetrically arranged parts. The connecting seat positioning mechanism 4 is located between the two welding part avoidance grooves 2-6.
[0017] See Figure 3 , Figure 6 The welding fixture for the shock-absorbing rear fork of the children's balance bike described in this utility model includes a bend positioning and clamping mechanism 5 comprising a bend positioning block 5-2 and a downward-pressing bend clamping clamp 5-1. The bend positioning block 5-2 is composed of two parts, left and right, each part having a bend positioning groove that matches the outer surface of the two bends. The downward-pressing bend clamping clamp 5-1 is arranged on the symmetrical axis of the left and right parts of the bend positioning block 5-2. The pressure head of the downward-pressing bend clamping clamp 5-1 is a pressure block extending in the left and right direction, which can press and fix the two bends 1-1 embedded in the bend positioning groove through the pressure block.
[0018] See Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 6 The welding fixture for the shock-absorbing rear fork of the children's balance bike described in this utility model includes a rear wheel axle lug positioning and clamping mechanism 6 comprising a rear wheel axle lug positioning seat 6-2 and a side-push type rear wheel axle lug positioning and clamping clamp 6-1. The rear wheel axle lug positioning seat 6-2 has rear wheel axle lug positioning pins 6-2-1 at both its left and right ends, and these pins 6-2-1 match the rear wheel axle mounting holes 1-3-1 on the rear wheel axle lugs 1-3. The side-push type rear wheel axle lug positioning and clamping clamp 6-1 is symmetrically arranged on the left and right sides, and has a rear wheel axle lug positioning pin clearance hole 6-1-1 at its clamping head. When positioning the rear wheel axle lugs 1-3, the rear wheel axle lug positioning pins 6-2-1 can pass through the rear wheel axle mounting holes 1-3-1 on the rear wheel axle lugs 1-3 and enter the rear wheel axle lug positioning pin clearance hole 6-1-1.
[0019] See Figure 1 , Figure 2 , Figure 3 , Figure 5 , Figure 6 The welding fixture for the shock-absorbing rear fork of the children's balance bike described in this utility model includes a flip shaft lug positioning mechanism 3 comprising a flip shaft lug positioning seat 3-2 and a side-push type flip shaft lug positioning clamp 3-1. The left and right end faces of the flip shaft lug positioning seat 3-2 are provided with flip shaft lug positioning holes 3-2-1, the diameter of which is smaller than the diameter of the flip shaft assembly hole 1-2-1 on the flip shaft lug 1-2. The side-push type flip shaft lug positioning clamp 3-1 is symmetrically arranged in two sets, each set having a positioning rod 3-1-1 that moves in the left and right direction. The front end of the positioning rod 3-1-1 can be inserted into the flip shaft lug positioning hole 3-2-1 of the flip shaft lug positioning seat 3-2.
[0020] See Figure 1 , Figure 3 , Figure 6 The welding fixture for the shock-absorbing rear fork of the children's balance bike described in this utility model includes a connecting seat positioning mechanism 4 comprising a connecting seat positioning block 4-1 and a connecting seat positioning pin 4-2. The connecting seat positioning block 4-1 is fixed to the base plate 2-2 through a central positioning hole 2-5 provided between the left and right welding part clearance grooves 2-6 on the base plate 2-2, and the positioning pin 4-2 is installed on the upper end face of the connecting seat positioning block 4-1. The positioning pin 4-2 matches the central hole 1-4-1 on the connecting seat 1-4.
[0021] See Figure 3 , Figure 6 , Figure 7 The welding fixture for the shock-absorbing rear fork of the children's balance bike described in this utility model is further provided with a flip-up axle lug positioning seat adjustment hole 2-3, a side-push flip-up axle lug positioning clamp adjustment hole 2-4, a bent tube positioning block adjustment hole 2-7, a rear wheel axle lug positioning seat adjustment hole 2-8, and a side-push rear wheel axle lug positioning clamp adjustment hole 2-9 on the base plate 2-2. The flip-up axle lug positioning seat adjustment hole 2-3 and the side-push flip-up axle lug positioning clamp adjustment hole 2-4 are longitudinal elongated holes arranged on the horizontal surface of the base plate; the bent tube positioning block adjustment hole 2-7 is a transverse elongated hole arranged on the inclined surface of the base plate; and the rear wheel axle lug positioning seat adjustment hole 2-8 and the side-push rear wheel axle lug positioning clamp adjustment hole 2-9 are longitudinal elongated holes arranged on the inclined surface of the base plate.
[0022] See Figures 1 to 8 When welding the shock-absorbing rear fork component 1 of a children's balance bike using this utility model, the workpiece clamping operation must first be completed. First, place the left and right sets of bent pipes 1-1 into the bent pipe positioning grooves of the left and right sets of bent pipe positioning blocks 5-2. Then, fit the rear wheel axle mounting holes 1-3-1 on the rear wheel axle lugs 1-3 of the left and right sets of bent pipes 1-1 onto the rear wheel axle lug positioning pins 6-2-1 of the rear wheel axle lug positioning seat 6-2. Then, operate the left and right sets of side-push flip-type axle lug positioning clamps 3-1, causing their positioning rods 3-1-1 to pass through the flip-axle mounting holes 1-2 on the flip-axle lugs 1-2. -1. Enter the flip shaft lug positioning hole 3-2-1 of the flip shaft lug positioning seat 3-2 to position the flip shaft lugs 1-2 of the left and right sets of bent tubes 1-1; after the above operation is completed, place the connecting seat 1-4 on the connecting seat positioning block 4-1, so that the connecting seat positioning pin 4-2 passes through the center hole 1-4-1 on the connecting seat 1-4; finally, operate the pressing type bent tube clamping pliers 5-1 to press and fix the bent tube 1-1 through the clamping block extending in the left and right direction of the clamping head, and operate the side-push type rear wheel axle lug positioning clamping pliers 6-1 to press and fix the rear wheel axle lugs 1-3 of the left and right bent tubes 1-1. During welding operations, the connecting seat 1-4 and the bend 1-1 can be welded on one side manually or by a welding robot. Then, the base 2 is rotated 180 degrees by a welding station indexing machine, and the other side of the connecting seat 1-4 and the bend 1-1 is welded through the two welding part avoidance grooves 2-6 on the horizontal plane S of the base plate, completing the full welding operation. This utility model can also adjust the relative positions of the components of the welding fixture through the adjustment holes 2-3, 2-4, 2-7, 2-8, and 2-9 of the flip shaft lug positioning seat, side-push flip shaft lug positioning clamp, bend positioning block, rear wheel axle lug positioning seat, and side-push rear wheel axle lug positioning clamp, which are provided on the base plate 2-2, to meet the welding operation requirements of workpieces of different specifications and sizes.
Claims
1. A welding fixture for the shock-absorbing rear fork of a children's balance bike, characterized in that: The system includes a base (2), a bend pipe positioning and clamping mechanism (5), a connecting seat positioning mechanism (4), a rear wheel axle lug positioning and clamping mechanism (6), and a flipping axle lug positioning mechanism (3). The base (2) includes a vertical plate (2-1) and a bottom plate (2-2). The bottom plate (2-2) consists of a horizontal surface (S) and an inclined surface (X). The angle between the inclined surface (X) and the horizontal surface (S) matches the bending angle of the bend pipe (1-1). One end of the horizontal surface (S) is fixedly mounted to the vertical plate (2-1). The base (2) is assembled with the indexing machine of the welding station via the upright plate (2-1). Two symmetrical welding part avoidance grooves (2-6) are provided on the horizontal plane (S) of the base plate. The bending pipe positioning and pressing mechanism (5) and the rear wheel axle trunnion positioning and pressing mechanism (6) are installed on the inclined plane (X) of the base plate. The connecting seat positioning mechanism (4) and the flipping axle trunnion positioning mechanism (3) are arranged on the horizontal plane (S) of the base plate, wherein the connecting seat positioning mechanism (4) is located between the two welding part avoidance grooves (2-6).
2. The welding fixture for the shock-absorbing rear fork of a children's balance bike according to claim 1, characterized in that: The pipe bending positioning and clamping mechanism (5) includes a pipe bending positioning block (5-2) and a downward-pressing pipe bending clamp (5-1); the pipe bending positioning block (5-2) is composed of two parts, left and right, and each part is provided with a pipe bending positioning groove that matches the outer surface of the left and right pipes; the downward-pressing pipe bending clamp (5-1) is arranged on the axis of symmetry of the left and right parts of the pipe bending positioning block (5-2), and the pressure head of the downward-pressing pipe bending clamp (5-1) is a pressure block extending in the left and right direction.
3. The welding fixture for the shock-absorbing rear fork of a children's balance bike according to claim 1 or 2, characterized in that: The rear wheel axle trunnion positioning and clamping mechanism (6) comprises two symmetrically arranged parts. Each part is provided with a rear wheel axle trunnion positioning seat (6-2) and a side-push type rear wheel axle trunnion positioning clamp (6-1). The rear wheel axle trunnion positioning seat (6-2) is provided with rear wheel axle trunnion positioning pins (6-2-1) at both ends. The rear wheel axle trunnion positioning pins (6-2-1) match the rear wheel axle assembly holes (1-3-1) on the rear wheel axle trunnion (1-3). The side-push type rear wheel axle trunnion positioning clamp (6-1) is symmetrically arranged. The clamping head of the side-push type rear wheel axle trunnion positioning clamp (6-1) is provided with a rear wheel axle trunnion positioning pin clearance hole (6-1-1).
4. The welding fixture for the shock-absorbing rear fork of a children's balance bike according to claim 3, characterized in that: The flip shaft lug positioning mechanism (3) comprises two symmetrically arranged parts, each of which is provided with a flip shaft lug positioning seat (3-2) and a side-push flip shaft lug positioning clamp (3-1). The flip shaft lug positioning seat (3-2) has flip shaft lug positioning holes (3-2-1) on both its left and right ends. The diameter of the flip shaft lug positioning holes (3-2-1) is smaller than the diameter of the flip shaft assembly hole (1-2-1) on the flip shaft lug (1-2). The side-push flip shaft lug positioning clamp (3-1) is arranged in two symmetrical sets, each set of which is provided with a positioning rod (3-1-1) that moves in the left and right directions. The front end of the positioning rod (3-1-1) can be inserted into the flip shaft lug positioning hole (3-2-1) of the flip shaft lug positioning seat (3-2).
5. The welding fixture for the shock-absorbing rear fork of a children's balance bike according to claim 1, characterized in that: The connecting seat positioning mechanism (4) includes a connecting seat positioning block (4-1) and a connecting seat positioning pin (4-2); the connecting seat positioning block (4-1) is fixed on the base plate (2-2) through a central positioning hole (2-5) provided between the left and right welding part clearance grooves (2-6) on the base plate (2-2), and a positioning pin (4-2) is installed on the upper end face of the connecting seat positioning block (4-1); the positioning pin (4-2) matches the central hole (1-4-1) on the connecting seat (1-4).
6. The welding fixture for the shock-absorbing rear fork of a children's balance bike according to claim 5, characterized in that: The base plate (2-2) of the base (2) is also provided with a flip shaft lug positioning seat adjustment hole (2-3), a side-push flip shaft lug positioning clamp adjustment hole (2-4), a bent pipe positioning block adjustment hole (2-7), a rear wheel axle lug positioning seat adjustment hole (2-8), and a side-push rear wheel axle lug positioning clamp adjustment hole (2-9); the flip shaft lug positioning seat adjustment hole (2-3) and the side-push flip shaft lug positioning clamp adjustment hole (2-4) are longitudinal long holes arranged on the horizontal surface of the base plate; the bent pipe positioning block adjustment hole (2-7) is a transverse long hole arranged on the inclined surface of the base plate; the rear wheel axle lug positioning seat adjustment hole (2-8) and the side-push rear wheel axle lug positioning clamp adjustment hole (2-9) are longitudinal long holes arranged on the inclined surface of the base plate.