Universal wheel cart

Abstract

A universal wheel cart, wherein the lower joint of the push rod is rotatably connected with the upper joint of the bracket, a front wheel orientation assembly capable of orienting the front wheel is provided between the front wheel joint and the front wheel seat assembly, a rear wheel orientation assembly capable of orienting the rear wheel is provided between the rear wheel joint and the rear wheel seat assembly, the front wheel connector at the upper joint of the bracket is connected with the front wheel orientation assembly, the rear wheel connector is connected with the rear wheel orientation assembly, the lower joint of the push rod can drive the reversing switch to act on the front wheel connector and the rear wheel connector simultaneously during the forward and backward rotation of the push rod, and can further drive the front wheel orientation assembly and the rear wheel orientation assembly to be linked so that the front wheel is in an oriented state and the rear wheel is in an omnidirectional state, or the front wheel is in an omnidirectional state and the rear wheel is in an oriented state. The advantage of the present invention is that the universal wheel cart can make the rear wheel in the forward direction of the cart only rotate forward and backward through the forward and backward rotation of the push rod, and the front wheel in the forward direction can always rotate in an omnidirectional manner, so as to facilitate pushing.

Description

Technical Field

[0001] The invention relates to a cart, in particular to a cart with universal wheels. Background Art

[0002] Many existing child strollers are generally provided with a push rod. In order to meet the different needs of the operator for forward and reverse pushing, the push rod is usually set to a reversible structure. After the push rod is reversed, the front wheel and the rear wheel need to be directionally unlocked and locked respectively, so that the front wheel in the pushing direction of the stroller can turn freely and the rear wheel is in a directional state, so as to ensure the normal driving of the stroller. In the prior art, although some child strollers are also provided with a front wheel directional assembly and a rear wheel directional assembly, and the front wheel directional assembly and the rear wheel directional assembly are automatically driven to automatically switch between the directional locking state and the directional unlocking state when the push rod is reversed, most of these structures are relatively complex, and some have problems such as poor operational stability, thereby affecting the overall use performance of the stroller. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a universal wheel cart with a simple structure and which can make the front wheel in the forward direction rotate in a universal direction and the rear wheel in the forward direction rotate only forward and backward through the forward and backward rotation of the push rod.

[0004] The technical solution adopted by the present invention to solve the above technical problems is as follows: the universal wheel cart comprises a front wheel bracket, a rear wheel bracket, a front wheel joint, a rear wheel joint, a front wheel seat assembly, a rear wheel seat assembly, a bracket upper joint, a push rod and a push rod lower joint, the front wheel joint is connected between the front wheel bracket and the front wheel seat assembly, the rear wheel joint is connected between the rear wheel bracket and the rear wheel seat assembly, the bracket upper joint is installed on the top of the front wheel bracket and the rear wheel bracket, the push rod lower joint is installed at the lower end of the push rod and is rotatably connected to the bracket upper joint, characterized in that: a front wheel orientation assembly capable of orienting the front wheel is provided between the front wheel joint and the front wheel seat assembly A rear wheel orientation assembly capable of orienting the rear wheel is provided between the rear wheel joint and the rear wheel seat assembly, a front wheel connecting member, a rear wheel connecting member and a reversing switch member are installed on the upper joint of the bracket, the front wheel connecting member is connected to the front wheel orientation assembly, the rear wheel connecting member is connected to the rear wheel orientation assembly, and the lower joint of the push rod can drive the reversing switch member to act on the front wheel connecting member and the rear wheel connecting member at the same time during the forward and backward rotation of the push rod, and can further drive the front wheel orientation assembly and the rear wheel orientation assembly to be linked so that the front wheel is in a directional state and the rear wheel is in a universal state, or the front wheel is in a universal state and the rear wheel is in a directional state.

[0005] Preferably, when the push rod is rotated backward to above the rear wheel bracket, the rear wheel is in a directional state and the front wheel is in a universal state, and when the push rod is rotated forward to above the front wheel bracket, the front wheel is in a directional state and the rear wheel is in a universal state.

[0006] In order to enable the reversing switching member to move inward and outward, the reversing switching member is laterally movably arranged in the upper joint of the bracket, and the outer side of the upper joint of the bracket is rotatably connected to the lower joint of the push rod. The lower joint of the push rod is provided with a guiding inclined surface that can abut against the outer end surface of the reversing switching member and enable the lower joint of the push rod to push the reversing switching member to move inward during the rotation process, and can further drive the front wheel connecting member and the rear wheel connecting member to move in opposite directions up and down. The front wheel connecting member and the rear wheel connecting member also have a tendency to move in the opposite direction under the action of the elastic member, and can further push the reversing switching member to move outward under the action of the elastic member.

[0007] The elastic member can have a variety of structural forms. Preferably, a connector installation box is provided on the inner side of the upper joint of the bracket, and the front wheel connector and the rear wheel connector are independently arranged side by side in the connector installation box. The elastic member includes a first spring acting on the front wheel connector and a second spring acting on the rear wheel connector.

[0008] Further preferably, the inner side surface of the reversing switch member is formed with a first inclined surface and a second inclined surface adjacent to each other in front and back, the front wheel connecting member is formed with a third inclined surface matched with the first inclined surface, the rear wheel connecting member is formed with a fourth inclined surface matched with the second inclined surface, the first inclined surface and the third inclined surface are both inclined obliquely outward from top to bottom, the second inclined surface and the fourth inclined surface are both inclined obliquely inward from top to bottom, the upper end of the first spring is against the bottom of the front wheel connecting member, the lower end of the first spring is against the bottom of the connecting member installation box, the upper end of the second spring is against the top of the connecting member installation box, and the lower end of the second spring is against the top of the rear wheel connecting member. In this way, when the reversing switch member moves inward, it can drive the front wheel connecting member to move downward and the rear wheel connecting member to move upward, and when the reversing switch member moves outward, it can drive the wheel connecting member to move upward and the rear wheel connecting member to move downward.

[0009] The guide bevel and the reversing switching member can have a variety of matching structures. Preferably, the guide bevel is distributed along the inner periphery of the lower joint of the push rod. When the push rod is rotated backward to its full position, the guide bevel is inclined inward from bottom to top, and the reversing switching member is close to the lower starting section of the guide bevel. When the push rod is rotated forward to its full position, the upper ending section of the guide bevel rotates to the bottom position and resists the reversing switching member.

[0010] In order to enable the front wheel connecting member to transmit motion to the front wheel orientation assembly and the rear wheel connecting member to transmit motion to the rear wheel alignment assembly, the front wheel connecting member is connected to the front wheel orientation assembly via a front wheel cable, and the rear wheel connecting member is connected to the rear wheel alignment assembly via a rear wheel cable. When the front wheel cable pulls the front wheel orientation assembly upwards to put the front wheel in a universal rotation state, the rear wheel cable releases the rear wheel alignment assembly to allow the rear wheel alignment assembly to orient the rear wheel. Accordingly, when the rear wheel cable pulls the rear wheel orientation assembly upwards to put the rear wheel in a universal rotation state, the front wheel cable releases the front wheel alignment assembly to allow the front wheel alignment assembly to orient the front wheel.

[0011] The front wheel orientation assembly and the rear wheel orientation assembly can have various structures. Preferably, the front wheel seat assembly is provided with a front wheel positioning hole, the front wheel orientation assembly includes a front wheel orientation spring and a front wheel orientation piece installed inside the front wheel joint, the front wheel cable is connected to the front wheel orientation piece, the front wheel orientation piece maintains a tendency to move downward under the action of the front wheel orientation spring, and the front wheel orientation piece can be inserted into the front wheel orientation hole when it moves downward to orient the front wheel, and the rear wheel seat assembly is provided with a rear wheel positioning hole, the rear wheel orientation assembly includes a rear wheel orientation spring and a rear wheel orientation piece installed inside the rear wheel joint, the rear wheel cable is connected to the rear wheel orientation piece, the rear wheel orientation piece maintains a tendency to move downward under the action of the rear wheel orientation spring, and the rear wheel orientation piece can be inserted into the rear wheel orientation hole when it moves downward to orient the rear wheel.

[0012] Further preferably, the front wheel seat assembly has a front wheel seat mounting hole, the front wheel joint has a front wheel joint rotating shaft inserted into the front wheel seat mounting hole, the front wheel positioning hole is arranged at the rear side of the front wheel seat assembly, the rear wheel seat assembly has a rear wheel seat mounting hole, the rear wheel joint has a rear wheel joint rotating shaft inserted into the rear wheel seat mounting hole, and the rear wheel positioning hole is arranged at the front side of the rear wheel seat assembly.

[0013] As a preferred embodiment of any of the above schemes, the front wheel bracket includes a left front wheel bracket and a right front wheel bracket, the rear wheel bracket includes a left rear wheel bracket and a right rear wheel bracket, and correspondingly, the bracket upper joint includes a left bracket upper joint and a right bracket upper joint, and the push rod lower joint includes a push rod lower left joint and a push rod lower right joint, the push rod lower left joint is rotatably connected to the left bracket upper joint, and the push rod lower right joint is rotatably connected to the right bracket upper joint.

[0014] Compared with the prior art, the advantages of the present invention are that the lower joint of the push rod of the universal wheel cart can drive the reversing switch member to act on the front wheel connecting member and the rear wheel connecting member simultaneously during the forward and backward rotation of the push rod, and can further drive the front wheel directional assembly and the rear wheel directional assembly to be linked so that the front wheel is in a directional state and the rear wheel is in a universal state, or the front wheel is in a universal state and the rear wheel is in a directional state. In this way, the rear wheel in the forward direction of the cart can only rotate forward and backward through the forward and backward rotation of the push rod, and the front wheel in the forward direction can always rotate in a universal direction, thereby facilitating pushing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of an embodiment of the present invention when the push rod is located at the rear of the frame;

[0016] Figure 2 for Figure 1 a side view of the cart shown;

[0017] Figure 3 It is a structural schematic diagram of a push rod lower joint and a bracket upper joint according to an embodiment of the present invention;

[0018] Figure 4 for Figure 3 A three-dimensional exploded schematic diagram of the structure shown;

[0019] Figure 5 It is a schematic structural diagram of a front wheel connecting member and a rear wheel connecting member according to an embodiment of the present invention;

[0020] Figure 6 It is a structural schematic diagram of a front wheel joint and a front wheel seat assembly according to an embodiment of the present invention;

[0021] Figure 7 for Figure 6 An exploded schematic diagram of the structure shown;

[0022] Figure 8 It is a schematic structural diagram of an embodiment of the present invention when the push rod is located in front of the frame;

[0023] Fig. 9 for Figure 8 Side view of the cart shown. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings.

[0025] like Figure 1 and Figure 2 As shown, Figure 2The direction indicated by the middle arrow A is forward, and the frame 100 of the universal wheel cart of this embodiment includes a front wheel bracket 1, a rear wheel bracket 2, a front wheel joint 3, a rear wheel joint 4, a front wheel seat assembly 5, a rear wheel seat assembly 6, a bracket upper joint 7, a push rod 8, a push rod lower joint 9 and a seat rod 10. Among them, the front wheel bracket 1 includes a left front wheel bracket and a right front wheel bracket, the rear wheel bracket 2 includes a left rear wheel bracket and a right rear wheel bracket, the front wheel joint 3 includes a left front wheel joint and a right front wheel joint, the rear wheel joint 4 includes a right front wheel joint and a right rear wheel joint, the front wheel seat assembly 5 includes a left front wheel seat assembly and a right front wheel seat assembly, the rear wheel seat assembly 6 includes a left rear wheel seat assembly and a right rear wheel seat assembly, the bracket upper joint 7 includes a left bracket upper joint and a right bracket upper joint, the push rod lower joint 9 includes a push rod lower left joint and a push rod lower right joint, the push rod lower left joint is rotatably connected to the left bracket upper joint, and the push rod lower right joint is rotatably connected to the right bracket upper joint. The seat post 10 is installed between the left bracket upper joint and the right bracket upper joint.

[0026] The front wheel joint 3 is connected between the front wheel bracket 1 and the front wheel seat assembly 5, the rear wheel joint 4 is connected between the rear wheel bracket 2 and the rear wheel seat assembly 6, the bracket upper joint 7 is installed on the top of the front wheel bracket 1 and the rear wheel bracket 2, and the push rod lower joint 9 is installed at the lower end of the push rod 8 and is rotatably connected to the bracket upper joint 7.

[0027] A front wheel orientation assembly 13 capable of orienting the front wheel 11 is provided between the front wheel joint 3 and the front wheel seat assembly 5, and a rear wheel orientation assembly 14 capable of orienting the rear wheel 12 is provided between the rear wheel joint 4 and the rear wheel seat assembly 6. A front wheel connector 15, a rear wheel connector 16 and a reversing switch 17 are installed on the bracket upper joint 7. The front wheel connector 15 is connected to the front wheel orientation assembly 13, and the rear wheel connector 16 is connected to the rear wheel orientation assembly 14. The push rod lower joint 9 can drive the reversing switch 17 to act on the front wheel connector 15 and the rear wheel connector 16 simultaneously during the forward and backward rotation of the push rod 8, and can further drive the front wheel orientation assembly 13 and the rear wheel orientation assembly 14 to be linked, so that the front wheel 11 is in a directional state and the rear wheel 12 is in a universal state, or the front wheel 11 is in a universal state and the rear wheel 12 is in a directional state.

[0028] In this embodiment, Figure 1 and Figure 2 As shown, when the push rod 8 is rotated backward to above the rear wheel bracket 2, the rear wheel 12 is in a directional state and the front wheel 11 is in a universal state, as shown in FIG. Figure 8 and Fig. 9 As shown, when the push rod 8 is rotated forward to the top of the front wheel bracket 1, the front wheel 11 is in a directional state and the rear wheel 12 is in a universal state.

[0029] like Figures 3 to 5As shown, the reversing switch member 17 of this embodiment is movably arranged in the bracket upper joint 7, and the push rod lower joint 9 is rotatably connected to the outer side of the bracket upper joint 7. The push rod lower joint 9 is provided with a guide bevel 91 that can abut against the outer end surface of the reversing switch member 17. During the rotation of the push rod lower joint 9, the guide bevel 91 can push the reversing switch member 17 to move inward, and can further drive the front wheel connecting member 15 and the rear wheel connecting member 16 to move up and down in reverse. In this embodiment, the guide bevel 91 is distributed along the inner periphery of the push rod lower joint 9. When the push rod 8 is rotated backward to the full position, the guide bevel 91 is inclined inward from bottom to top, and the reversing switch member 17 is close to the lower starting section of the guide bevel 91. When the push rod 8 is rotated forward to the full position, the upper end section of the guide bevel 91 rotates to the bottom position and abuts against the reversing switch member 17.

[0030] In addition, the front wheel connecting member 15 and the rear wheel connecting member 16 each have a tendency to move in the opposite direction under the action of the elastic member, and can further push the reversing switch member 17 to move outward under the action of the elastic member. Specifically, a connecting member installation box 71 is provided on the inner side of the bracket upper joint 7, and the front wheel connecting member 15 and the rear wheel connecting member 16 are independently arranged side by side in the front and rear directions in the connecting member installation box 71, and the elastic member includes a first spring 18 acting on the front wheel connecting member 15 and a second spring 19 acting on the rear wheel connecting member 16. In this embodiment, the inner side surface of the reversing switch 17 is formed with a first inclined surface 171 and a second inclined surface 172 adjacent to each other in front and back, the front wheel connecting member 15 is formed with a third inclined surface 151 matching with the first inclined surface 171, and the rear wheel connecting member 16 is formed with a fourth inclined surface 161 matching with the second inclined surface 172. The first inclined surface 171 and the third inclined surface 151 are both inclined outwardly from top to bottom, and the second inclined surface 172 and the fourth inclined surface 161 are both inclined inwardly from top to bottom. The upper end of the first spring 18 abuts against the bottom of the front wheel connecting member 15, the lower end of the first spring 18 abuts against the bottom of the connecting member installation box 71, the upper end of the second spring 19 abuts against the top of the connecting member installation box 71, and the lower end of the second spring 19 abuts against the top of the rear wheel connecting member 16. In this way, under the action of the first spring 18 and the second spring 19, the reversing switch 17 can be pushed to move outward.

[0031] like Figure 2 and Fig. 9As shown, the front wheel connecting member 15 is connected to the front wheel orientation assembly 13 through the front wheel cable 20, and the rear wheel connecting member 16 is connected to the rear wheel positioning assembly 14 through the rear wheel cable 21. When the front wheel cable 20 pulls the front wheel orientation assembly 13 upwards to make the front wheel 11 in a universal rotation state, the rear wheel cable 21 releases the rear wheel positioning assembly 14 to make the rear wheel positioning assembly 14 orient the rear wheel 12. Correspondingly, when the rear wheel cable 21 pulls the rear wheel orientation assembly 14 upwards to make the rear wheel 12 in a universal rotation state, the front wheel cable 20 releases the front wheel positioning assembly 13 to make the front wheel positioning assembly 13 orient the front wheel 11.

[0032] like Figure 6 to Figure 7 As shown, the front wheel seat assembly 5 is provided with a front wheel seat mounting hole 52, and the front wheel joint 3 is provided with a front wheel joint rotating shaft 31. The front wheel joint rotating shaft 31 is inserted into the front wheel seat mounting hole 52, and the front wheel joint 3 can rotate relative to the front wheel seat assembly 5. The front wheel seat assembly 5 is also provided with a front wheel positioning hole 51, and the front wheel positioning hole 51 is arranged at the rear side of the front wheel seat assembly 5. The front wheel orientation assembly 13 includes a front wheel orientation spring 131 and a front wheel orientation member 132 installed inside the front wheel joint 3. The lower end of the front wheel cable 20 is connected to the front wheel orientation member 132. The front wheel orientation member 132 maintains a tendency to move downward under the action of the front wheel orientation spring 131, and the front wheel orientation member 132 moves downward to be inserted into the front wheel positioning hole 51 to orient the front wheel 11.

[0033] Similarly, the rear wheel seat assembly 6 is provided with a rear wheel seat mounting hole (not shown in the figure), and the rear wheel joint 4 has a rear wheel joint rotating shaft (not shown in the figure) inserted into the rear wheel seat mounting hole. The rear wheel joint rotating shaft is inserted into the rear wheel seat mounting hole, and the rear wheel joint 4 can rotate relative to the rear wheel seat assembly 6. The rear wheel seat assembly 6 is also provided with a rear wheel positioning hole (not shown in the figure), and the rear wheel positioning hole is arranged at the front side of the rear wheel seat assembly 6. The rear wheel orientation assembly 14 includes a rear wheel orientation spring 141 and a rear wheel orientation member 142 installed inside the rear wheel joint 4. The rear wheel cable 21 is connected to the rear wheel orientation member 142. The rear wheel orientation member 142 maintains a downward movement tendency under the action of the rear wheel orientation spring 141, and the rear wheel orientation member 142 moves downward and can be inserted into the rear wheel positioning hole to orient the rear wheel 12.

[0034] The orientation principle of the front and rear wheels of the universal wheel cart is as follows:

[0035] When the push rod 8 rotates to the front side, Figure 2 The indicated position goes to Fig. 9During the process of the position shown, the push rod lower joint 9 pushes the reversing switch member 17 to move toward the inside of the frame 100, and the reversing switch member 17 then pushes the front wheel connecting member 15 to move downward, the front wheel cable 20 is relaxed, and the front wheel directional member 132 in the front wheel joint 3 moves downward under the action of the front wheel directional spring 131, and is inserted into the front wheel directional hole 51 of the front wheel seat assembly 5, thereby orienting the front wheel seat assembly 5, so that the front wheel 11 can only rotate forward and backward but not universally rotate. At the same time, the reversing switch member 17 pushes the rear wheel connecting member 16 to move upward, pulls the rear wheel cable 21, and then drives the rear wheel directional member 142 to move upward, so that the rear wheel seat assembly 6 can rotate universally.

[0036] On the contrary, the push rod 8 rotates to the rear side, that is, Fig. 9 Rotate the position shown Figure 2 During the process of the position shown in the figure, the front wheel connecting member 15 is reset upwards under the action of the first spring 18, and the rear wheel connecting member 16 is reset downwards under the action of the second spring 19, thereby driving the reversing switch member 17 to move toward the outside of the frame 100, and the reversing switch member 17 always keeps in contact with the guiding inclined surface 91 of the lower joint 9 of the push rod during the movement. As the front wheel connecting member 15 is reset upwards, the front wheel cable 20 drives the front wheel directional member 132 to move upwards and disengage from the front wheel seat assembly 5, so that the front wheel seat assembly 5 is in a universal rotation state. Correspondingly, as the rear wheel connecting member 16 is reset downwards, the rear wheel cable 21 is relaxed, and the rear wheel directional member 142 in the rear wheel joint 4 moves downwards under the action of the rear wheel directional spring 141, and is inserted into the rear wheel directional hole 61 of the rear wheel seat assembly 6, thereby orienting the rear wheel seat assembly 6, so that the rear wheel 12 can only rotate forward and backward but not universally rotate.

[0037] It can be seen from the above working principle that when the push rod 8 rotates from the rear side of the frame 100 to the front side, that is, from Figure 2 Position rotated to Fig. 9 Location, Figure 2 The front wheels in the cart become the rear wheels in the direction of travel. Figure 2 The rear wheel in the vehicle frame 100 becomes the front wheel in the forward direction of the vehicle frame. Conversely, when the push rod 8 rotates from the front side of the vehicle frame 100 to the rear side, that is, from Fig. 9 Position rotated to Figure 2 Location, Fig. 9 The front wheel in the direction of travel becomes the rear wheel. Fig. 9 The rear wheel in the forward direction of the cart becomes the front wheel. In short, the front wheel in the forward direction of the cart is always in a universal rotation state, and the rear wheel in the forward direction of the cart is in a directional state, which is convenient for pushing.

[0038] The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this field, various modifications or improvements can be made to the present invention without departing from the principle of the present invention, which are all considered to be within the scope of protection of the present invention.

Claims

1. A universal wheel cart, comprising a front wheel bracket (1), a rear wheel bracket (2), a front wheel joint (3), a rear wheel joint (4), a front wheel seat assembly (5), a rear wheel seat assembly (6), a bracket upper joint (7), a push rod (8) and a push rod lower joint (9), wherein the front wheel joint (3) is connected between the front wheel bracket (1) and the front wheel seat assembly (5), the rear wheel joint (4) is connected between the rear wheel bracket (2) and the rear wheel seat assembly (6), the bracket upper joint (7) is mounted on the top of the front wheel bracket (1) and the rear wheel bracket (2), the push rod lower joint (9) is mounted on the lower end of the push rod (8) and is rotatably connected to the bracket upper joint (7), characterized in that: A front wheel orientation assembly (13) capable of orienting the front wheel (11) is provided between the front wheel joint (3) and the front wheel seat assembly (5); a rear wheel orientation assembly (14) capable of orienting the rear wheel (12) is provided between the rear wheel joint (4) and the rear wheel seat assembly (6); a front wheel connecting member (15), a rear wheel connecting member (16) and a reversing switching member (17) are installed on the bracket upper joint (7); the front wheel connecting member (15) is connected to the front wheel orientation assembly (13); the rear wheel connecting member (16) is connected to the front wheel orientation assembly (13); and the rear wheel connecting member (16) is connected to the rear wheel orientation assembly (17). (16) is connected to the rear wheel orientation component (14), and the push rod lower joint (9) can drive the reversing switch member (17) to act on the front wheel connecting member (15) and the rear wheel connecting member (16) simultaneously during the forward and backward rotation of the push rod (8), and can further drive the front wheel orientation component (13) and the rear wheel orientation component (14) to be linked so that the front wheel (11) is in an orientation state and the rear wheel (12) is in a universal state, or the front wheel (11) is in a universal state and the rear wheel (12) is in an orientation state, When the push rod (8) rotates backward to the position above the rear wheel bracket (2), the rear wheel (12) is in a directional state and the front wheel (11) is in a universal state. When the push rod (8) rotates forward to the position above the front wheel bracket (1), the front wheel (11) is in a directional state and the rear wheel (12) is in a universal state. The reversing switching member (17) is laterally movable and arranged in the upper joint (7) of the bracket. The outer side of the upper joint (7) of the bracket is rotatably connected to the push rod lower joint (9). The lower joint (9) is provided with a guide inclined surface (91) which can abut against the outer end surface of the reversing switching member (17) and enable the push rod lower joint (9) to push the reversing switching member (17) to move inward during rotation, and can further drive the front wheel connecting member (15) and the rear wheel connecting member (16) to move in the up and down directions. The front wheel connecting member (15) and the rear wheel connecting member (16) also have a tendency to move in the opposite direction under the action of the elastic member, and can further push the reversing switching member (17) to move outward under the action of the elastic member.

2. The universal wheel cart according to claim 1, characterized in that: A connecting member installation box (71) is provided on the inner side of the bracket upper joint (7), the front wheel connecting member (15) and the rear wheel connecting member (16) are independently arranged in parallel in the front and rear directions in the connecting member installation box (71), and the elastic member comprises a first spring (18) acting on the front wheel connecting member (15) and a second spring (19) acting on the rear wheel connecting member (16).

3. The universal wheel cart according to claim 2, characterized in that: A first inclined surface (171) and a second inclined surface (172) adjacent to each other are formed on the inner side surface of the reversing switching member (17); a third inclined surface (151) matching with the first inclined surface (171) is formed on the front wheel connecting member (15); a fourth inclined surface (161) matching with the second inclined surface (172) is formed on the rear wheel connecting member (16); the first inclined surface (171) and the third inclined surface (151) are both inclined outwardly from top to bottom; the second inclined surface (172) and the fourth inclined surface (161) are both inclined inwardly from top to bottom; the upper end of the first spring (18) abuts against the bottom of the front wheel connecting member (15); the lower end of the first spring (18) abuts against the bottom of the connecting member installation box (71); the upper end of the second spring (19) abuts against the top of the connecting member installation box (71); and the lower end of the second spring (19) abuts against the top of the rear wheel connecting member (16).

4. The universal wheel cart according to claim 3, characterized in that: The guide bevel (91) is distributed along the inner periphery of the lower joint (9) of the push rod. When the push rod (8) is rotated backward to its full position, the guide bevel (91) is inclined inward from bottom to top, and the reversing switch member (17) is close to the lower starting section of the guide bevel (91). When the push rod (8) is rotated forward to its full position, the upper ending section of the guide bevel (91) is rotated to the bottom position and abuts against the reversing switch member (17).

5. The universal wheel cart according to claim 1, characterized in that: The front wheel connecting member (15) is connected to the front wheel orientation assembly (13) via a front wheel cable (20), and the rear wheel connecting member (16) is connected to the rear wheel positioning assembly (14) via a rear wheel cable (21). When the front wheel cable (20) pulls the front wheel orientation assembly (13) upwards to make the front wheel (11) in a universal rotation state, the rear wheel cable (21) releases the rear wheel positioning assembly (14) to make the rear wheel positioning assembly (14) orient the rear wheel (12). Correspondingly, when the rear wheel cable (21) pulls the rear wheel orientation assembly (14) upwards to make the rear wheel (12) in a universal rotation state, the front wheel cable (20) releases the front wheel positioning assembly (13) to make the front wheel positioning assembly (13) orient the front wheel (11).

6. The universal wheel cart according to claim 5, characterized in that: The front wheel seat assembly (5) is provided with a front wheel positioning hole (51), the front wheel orientation assembly (13) comprises a front wheel orientation spring (131) and a front wheel orientation member (132) installed inside the front wheel joint (3), the front wheel cable (20) is connected to the front wheel orientation member (132), the front wheel orientation member (132) maintains a tendency to move downward under the action of the front wheel orientation spring (131), and the front wheel orientation member (132) moves downward and can be inserted into the front wheel positioning hole (51) to position the front wheel. The rear wheel seat assembly (6) is provided with a rear wheel positioning hole, the rear wheel orientation assembly (14) comprises a rear wheel orientation spring (141) and a rear wheel orientation member (142) installed inside the rear wheel joint (4), the rear wheel cable (21) is connected to the rear wheel orientation member (142), the rear wheel orientation member (142) maintains a downward movement tendency under the action of the rear wheel orientation spring (141), and the rear wheel orientation member (142) moves downward and can be inserted into the rear wheel positioning hole to orient the rear wheel (12).

7. The universal wheel cart according to claim 6, characterized in that: The front wheel seat assembly (5) is provided with a front wheel seat mounting hole (52), the front wheel joint (3) has a front wheel joint rotating shaft (31) inserted into the front wheel seat mounting hole (52), the front wheel positioning hole (51) is arranged at the rear side of the front wheel seat assembly (5), the rear wheel seat assembly (6) is provided with a rear wheel seat mounting hole, the rear wheel joint (4) has a rear wheel joint rotating shaft inserted into the rear wheel seat mounting hole, and the rear wheel positioning hole is arranged at the front side of the rear wheel seat assembly (6).

8. The universal wheel cart according to any one of claims 1 to 7, characterized in that: The front wheel bracket (1) includes a left front wheel bracket and a right front wheel bracket, the rear wheel bracket (2) includes a left rear wheel bracket and a right rear wheel bracket, and correspondingly, the bracket upper joint (7) includes a left bracket upper joint and a right bracket upper joint, and the push rod lower joint (9) includes a push rod lower left joint and a push rod lower right joint, the push rod lower left joint is rotatably connected to the left bracket upper joint, and the push rod lower right joint is rotatably connected to the right bracket upper joint.

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