阅读说明：本技术 一种万向轮推车 (Universal wheel cart ) 是由 徐有伟 缪开华 于 2019-12-16 设计创作，主要内容包括：一种万向轮推车,其推杆下接头与支架上接头转动连接,在前轮接头与前轮座组件之间设有能对前轮进行定向的前轮定向组件,在后轮接头与后轮座组件之间设有能对后轮进行定向的后轮定向组件,在支架上接头的前轮连接件与前轮定向组件相连接,后轮连接件与后轮定向组件相连接,推杆下接头随推杆前后转动过程中能驱动换向切换件同时作用于前轮连接件和后轮连接件,并能进而通过带动前轮定向组件和后轮定向组件联动而使前轮处于定向状态且后轮处于万向状态,或者使前轮处于万向状态且后轮处于定向状态。本发明的优点在于：该万向轮推车通过推杆的前后转动可以使推车前进方向的后轮只能前后向转动,前进方向的前轮始终可以万向转动,从而便于推行。(A push rod lower joint of the universal wheel cart is rotatably connected with a support upper joint, a front wheel orientation assembly capable of orienting a front wheel is arranged between the front wheel joint and the front wheel seat assembly, a rear wheel orientation assembly capable of orienting a rear wheel is arranged between the rear wheel joint and the rear wheel seat assembly, a front wheel connecting piece of the support upper joint is connected with the front wheel orientation assembly, a rear wheel connecting piece is connected with the rear wheel orientation assembly, the push rod lower joint can drive a reversing switching piece to simultaneously act on the front wheel connecting piece and the rear wheel connecting piece along with the forward and backward rotation of the push rod, and the front wheel can be in an orientation state and the rear wheel can be in an universal state or the front wheel can be in an orientation state and the rear wheel can be in an orientation state by driving the linkage of the front wheel orientation assembly and the rear wheel orientation assembly. The invention has the advantages that: the universal wheel cart can ensure that the rear wheels in the advancing direction of the cart can only rotate forwards and backwards through the forward and backward rotation of the push rod, and the front wheels in the advancing direction can always rotate universally, so that the cart is convenient to push.)

1. The utility model provides an universal wheel shallow, includes front wheel support (1), rear wheel support (2), front wheel joint (3), rear wheel joint (4), front wheel seat subassembly (5), rear wheel seat subassembly (6), support upper joint (7), push rod (8) and push rod lower clutch (9), front wheel joint (3) are connected between front wheel support (1) and front wheel seat subassembly (5), rear wheel joint (4) are connected between rear wheel support (2) and rear wheel seat subassembly (6), the top at front wheel support (1) and rear wheel support (2) is installed in support upper joint (7), push rod lower clutch (9) install push rod (8) lower extreme and with support upper joint (7) rotate to be connected its characterized in that: a front wheel orientation component (13) capable of orienting the front wheel (11) is arranged between the front wheel joint (3) and the front wheel seat component (5), a rear wheel orientation component (14) capable of orienting the rear wheel (12) is arranged between the rear wheel joint (4) and the rear wheel seat component (6), a front wheel connecting piece (15), a rear wheel connecting piece (16) and a reversing switching piece (17) are arranged on the bracket upper joint (7), the front wheel connecting piece (15) is connected with the front wheel orientation component (13), the rear wheel connecting piece (16) is connected with the rear wheel orientation component (14), the push rod lower joint (9) can drive the reversing switching piece (17) to simultaneously act on the front wheel connecting piece (15) and the rear wheel connecting piece (16) along with the forward and backward rotation of the push rod (8), and can further enable the front wheel (11) to be in an oriented state and the rear wheel (12) to be linked by driving the front wheel orientation component (13) and the rear wheel orientation component (14) The front wheels (11) are in a universal state, or the rear wheels (12) are in a directional state.

2. The steerable wheel cart of claim 1, wherein: under the state that push rod (8) backward rotates to rear wheel support (2) top, rear wheel (12) are in the oriented state and front wheel (11) are in universal state, under the state that push rod (8) forward rotates to front wheel support (1) top, front wheel (11) are in the oriented state and rear wheel (12) are in universal state.

3. The steerable wheel cart of claim 1, wherein: the reversing switching piece (17) is transversely and movably arranged in the upper bracket joint (7), the outer side of the upper bracket joint (7) is rotatably connected with the lower push rod joint (9), the lower push rod joint (9) is provided with a guide inclined plane (91) which can be abutted against the outer end face of the reversing switching piece (17), the lower push rod joint (9) can push the reversing switching piece (17) to move inwards in the rotating process and can further drive the front wheel connecting piece (15) and the rear wheel connecting piece (16) to move up and down in the reverse direction, the front wheel connecting piece (15) and the rear wheel connecting piece (16) respectively have the tendency of reverse movement under the action of the elastic piece, and can further push the reversing switching piece (17) to move outwards under the action of the elastic piece.

4. The gimbaled wheel cart of claim 3, wherein: the inner side of the support upper joint (7) is provided with a connecting piece mounting box (71), the front wheel connecting piece (15) and the rear wheel connecting piece (16) are independently arranged in the connecting piece mounting box (71) in a front-back side-by-side mode, and the elastic piece comprises a first spring (18) acting on the front wheel connecting piece (15) and a second spring (19) acting on the rear wheel connecting piece (16).

5. The gimbaled wheel cart of claim 4, wherein: a first inclined plane (171) and a second inclined plane (172) which are adjacent in the front and back are formed on the inner side surface of the reversing switching piece (17), a third inclined surface (151) matched with the first inclined surface (171) is formed on the front wheel connecting piece (15), a fourth inclined surface (161) matched with the second inclined surface (172) is formed on the rear wheel connecting piece (16), the first inclined plane (171) and the third inclined plane (151) are inclined outwards from top to bottom, the second inclined plane (172) and the fourth inclined plane (161) are inclined inwards from top to bottom, the upper end of the first spring (18) is propped against the bottom of the front wheel connecting piece (15), the lower end of the first spring (18) is propped against the bottom of the connecting piece mounting box (71), the upper end of the second spring (19) is abutted against the top of the connecting piece mounting box (71), and the lower end of the second spring (19) is abutted against the top of the rear wheel connecting piece (16).

6. The gimbaled wheel cart of claim 5, wherein: the guide slope (91) is distributed along the inner side periphery of the lower connector (9) of the push rod, the push rod (8) rotates backwards to be in place, the guide slope (91) inclines inwards from bottom to top, the reversing switching piece (17) is close to the lower starting section of the guide slope (91), and the upper ending section of the guide slope (91) rotates to the bottom position and the reversing switching piece (17) is abutted under the condition that the push rod (8) rotates forwards to be in place.

7. The steerable wheel cart of claim 1, wherein: the front wheel connecting piece (15) is connected with the front wheel orientation assembly (13) through a front wheel inhaul cable (20), the rear wheel connecting piece (16) is connected with the rear wheel orientation assembly (14) through a rear wheel inhaul cable (21), the front wheel orientation assembly (13) is upwards pulled by the front wheel inhaul cable (20) to enable the front wheel (11) to be in a universal rotating state, the rear wheel inhaul cable (21) releases the rear wheel orientation assembly (14) to enable the rear wheel orientation assembly (14) to orient the rear wheel (12), correspondingly, the rear wheel inhaul cable (21) upwards pulls the rear wheel orientation assembly (14) to enable the rear wheel (12) to be in a universal rotating state, and the front wheel inhaul cable (20) releases the front wheel orientation assembly (13) to enable the front wheel orientation assembly (13) to orient the front wheel (11).

8. The gimbaled wheel cart of claim 7, wherein: 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 piece (132) which are arranged in the front wheel joint (3), the front wheel inhaul cable (20) is connected to the front wheel orientation piece (132), the front wheel orientation piece (132) keeps a downward movement trend under the action of the front wheel orientation spring (131), the front wheel orientation piece (132) moves downward and can be inserted into the front wheel positioning hole (51) to orient 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 piece (142) which are arranged in the rear wheel joint (4), the rear wheel inhaul cable (21) is connected to the rear wheel orientation piece (142), and the rear wheel orientation piece (142) keeps a downward movement trend under the action of the rear wheel orientation spring (141), and the rear wheel orienting piece (142) moves downwards and can be inserted into the rear wheel positioning hole to orient the rear wheel (12).

9. The gimbaled wheel cart of claim 8, wherein: it has front wheel seat mounting hole (52) to open on front wheel seat subassembly (5), front wheel connects (3) to have and inserts front wheel joint pivot (31) in front wheel seat mounting hole (52), front wheel locating hole (51) are located the rear side portion of front wheel seat subassembly (5), it has rear wheel seat mounting hole to open on rear wheel seat subassembly (6), rear wheel connects (4) to have and inserts rear wheel joint pivot in the rear wheel seat mounting hole, the rear wheel locating hole is located the front side portion of rear wheel seat subassembly (6).

10. The universal wheel cart according to any one of claims 1 to 9, wherein the front wheel support (1) comprises a left front wheel support and a right front wheel support, the rear wheel support (2) comprises a left rear wheel support and a right rear wheel support, correspondingly, the support upper joint (7) comprises a left support upper joint and a right support upper joint, the push rod lower joint (9) comprises 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 support upper joint, and the push rod lower right joint is rotatably connected to the right support upper joint.

Technical Field

The invention relates to a cart, in particular to a universal wheel cart.

Background

The push rod is usually set to be a reversible structure, and 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 can freely turn and the rear wheel is in a directional state in the pushing direction of the stroller, and the normal running of the stroller is ensured. In the prior art, although some baby strollers are 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 directional locking and directional unlocking states through reversing operation of a push rod, most of the structures are complex, and the problems of poor operation stability and the like exist in some cases, so that the overall use performance of the stroller is influenced.

Disclosure of Invention

The present invention is directed to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a universal wheel cart which has a simple structure, and can rotate a front wheel in a forward direction in a universal direction by forward and backward rotation of a push rod, and can rotate a rear wheel in the forward direction only in the forward and backward directions.

The technical scheme adopted by the invention for solving the technical problems is as follows: this universal wheel shallow, including front wheel support, rear wheel support, front wheel joint, rear wheel joint, front wheel seat subassembly, rear wheel seat subassembly, support upper joint, push rod and push rod lower clutch, front wheel articulate is between front wheel support and front wheel seat subassembly, rear wheel articulate is between rear wheel support and rear wheel seat subassembly, the support upper joint is installed at the top of front wheel support and rear wheel support, the push rod lower clutch install at the push rod lower extreme and with the support upper joint rotates to be connected its characterized in that: the front wheel orienting component capable of orienting the front wheel is arranged between the front wheel joint and the front wheel seat component, the rear wheel orienting component capable of orienting the rear wheel is arranged between the rear wheel joint and the rear wheel seat component, the upper joint of the bracket is provided with a front wheel connecting piece, a rear wheel connecting piece and a reversing switching piece, the front wheel connecting piece is connected with the front wheel orienting component, the rear wheel connecting piece is connected with the rear wheel orienting component, the lower joint of the push rod can drive the reversing switching piece to simultaneously act on the front wheel connecting piece and the rear wheel connecting piece in the process of rotating forwards and backwards along with the push rod, and the front wheel is in an orienting 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 an orienting state by driving the front wheel orienting component and the rear wheel orienting component to be linked.

Preferably, the rear wheel is in an oriented state and the front wheel is in a universal state in a state where the push rod is rotated rearward above the rear wheel bracket, and the front wheel is in an oriented state and the rear wheel is in a universal state in a state where the push rod is rotated forward above the front wheel bracket.

In order to enable the reversing switching piece to move inwards and outwards, the reversing switching piece is transversely movably arranged in the upper support joint, the outer side of the upper support joint is rotatably connected with the lower push rod joint, the lower push rod joint is provided with a guide inclined plane capable of abutting against the outer end face of the reversing switching piece, the lower push rod joint can push the reversing switching piece to move inwards in the rotating process and can further drive the front wheel connecting piece and the rear wheel connecting piece to move up and down in a reverse mode, and the front wheel connecting piece and the rear wheel connecting piece respectively have a reverse movement trend under the action of the elastic pieces and can further push the reversing switching piece to move outwards under the action of the elastic pieces.

The elastic member can have various structural forms, and preferably, a connecting member mounting box is arranged on the inner side of the upper joint of the bracket, the front wheel connecting member and the rear wheel connecting member are independently arranged in the connecting member mounting box in a front-back side-by-side mode, and the elastic member comprises a first spring acting on the front wheel connecting member and a second spring acting on the rear wheel connecting member.

Preferably, a first inclined plane and a second inclined plane which are adjacent to each other in the front-back direction are formed on the inner side face of the reversing switching piece, a third inclined plane matched with the first inclined plane is formed on the front wheel connecting piece, a fourth inclined plane matched with the second inclined plane is formed on the rear wheel connecting piece, the first inclined plane and the third inclined plane are inclined outwards from top to bottom, the second inclined plane and the fourth inclined plane are inclined inwards from top to bottom, the upper end of the first spring abuts against the bottom of the front wheel connecting piece, the lower end of the first spring abuts against the bottom of the connecting piece mounting box, the upper end of the second spring abuts against the top of the connecting piece mounting box, and the lower end of the second spring abuts against the top of the rear wheel connecting piece. Therefore, when the reversing switching piece moves inwards, the front wheel connecting piece can be driven to move downwards and the rear wheel connecting piece can be driven to move upwards, and when the reversing switching piece moves outwards, the wheel connecting piece can be driven to move upwards and the rear wheel connecting piece can move downwards.

The guide inclined plane and the reversing switching piece can have various matching structures, preferably, the guide inclined plane is distributed along the periphery of the inner side of the lower joint of the push rod, the guide inclined plane is inclined inwards from bottom to top in an inclined mode when the push rod rotates backwards in place, the reversing switching piece is close to the lower starting section of the guide inclined plane, and the upper ending section of the guide inclined plane rotates to the bottom position and the reversing switching piece is abutted when the push rod rotates forwards in place.

In order to enable the front wheel connecting piece to transmit motion to the front wheel orientation assembly and enable the rear wheel connecting piece to transmit motion to the rear wheel orientation assembly, the front wheel connecting piece is connected with the front wheel orientation assembly through a front wheel inhaul cable, the rear wheel connecting piece is connected with the rear wheel orientation assembly through a rear wheel inhaul cable, the front wheel inhaul cable upwards pulls the front wheel orientation assembly to enable the front wheel to be in a universal rotating state, the rear wheel inhaul cable loosens the rear wheel orientation assembly to enable the rear wheel orientation assembly to orient the rear wheel, correspondingly, the rear wheel inhaul cable upwards pulls the rear wheel orientation assembly to enable the rear wheel to be in a universal rotating state, and the front wheel inhaul cable loosens the front wheel orientation assembly to enable the front wheel orientation assembly to orient the front wheel.

The front wheel orientation component and the rear wheel orientation component can have various structures, and preferably, the front wheel seat component is provided with a front wheel positioning hole, the front wheel orientation assembly comprises a front wheel orientation spring and a front wheel orientation piece which are arranged inside the front wheel joint, the front wheel inhaul cable is connected to the front wheel directional piece, the front wheel directional piece keeps the trend of moving downwards under the action of the front wheel directional spring, and the front wheel orienting piece can move downwards and can be inserted into the front wheel positioning hole to orient the front wheel, the rear wheel seat component is provided with a rear wheel positioning hole, the rear wheel orientation assembly comprises a rear wheel orientation spring and a rear wheel orientation member which are arranged in the rear wheel joint, the rear wheel inhaul cable is connected to the rear wheel directional piece, the rear wheel directional piece keeps a downward movement trend under the action of the rear wheel directional spring, and the rear wheel directional piece moves downward and can be inserted into the rear wheel positioning hole to orient the rear wheel.

Preferably, the front wheel seat assembly is provided with a front wheel seat mounting hole, the front wheel joint is provided with a front wheel joint rotating shaft inserted into the front wheel seat mounting hole, the front wheel positioning hole is formed in the rear side portion of the front wheel seat assembly, the rear wheel seat assembly is provided with a rear wheel seat mounting hole, the rear wheel joint is provided with a rear wheel joint rotating shaft inserted into the rear wheel seat mounting hole, and the rear wheel positioning hole is formed in the front side portion of the rear wheel seat assembly.

As the optimization of any one of the above schemes, the front wheel support comprises a left front wheel support and a right front wheel support, the rear wheel support comprises a left rear wheel support and a right rear wheel support, correspondingly, the support upper joint comprises a left support upper joint and a right support upper joint, the push rod lower joint comprises 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 support upper joint, and the push rod lower right joint is rotatably connected to the right support upper joint.

Compared with the prior art, the invention has the advantages that: the push rod lower joint of the universal wheel cart can drive the reversing switching piece to simultaneously act on the front wheel connecting piece and the rear wheel connecting piece along with the forward and backward rotation process of the push rod, and can further enable the front wheel to be in an oriented state and the rear wheel to be in an oriented state by driving the front wheel orientation assembly and the rear wheel orientation assembly to be linked, or enable the front wheel to be in an oriented state and the rear wheel to be in an oriented state, so that the rear wheel in the advancing direction of the cart can only rotate forwards and backwards through the forward and backward rotation of the push rod, the front wheel in the advancing direction can always rotate universally, and the pushing is facilitated.

Drawings

FIG. 1 is a schematic structural view of a push rod of an embodiment of the present invention in a state of being located behind a vehicle frame;

FIG. 2 is a side view of the cart shown in FIG. 1;

FIG. 3 is a schematic structural diagram of a lower joint of the push rod and an upper joint of the bracket according to the embodiment of the invention;

FIG. 4 is an exploded perspective view of the structure shown in FIG. 3;

FIG. 5 is a schematic structural view of a front wheel attachment member and a rear wheel attachment member of an embodiment of the present invention;

FIG. 6 is a schematic structural view of a front wheel adapter and a front wheel base assembly according to an embodiment of the present invention;

FIG. 7 is an exploded view of the structure shown in FIG. 6;

FIG. 8 is a schematic structural view of the push rod of the embodiment of the present invention in a state where the push rod is positioned in front of the frame;

fig. 9 is a side view of the cart shown in fig. 8.

Detailed Description

The invention is described in further detail below with reference to the accompanying examples.

As shown in fig. 1 and 2, the frame 100 of the universal-wheel cart of the present 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 post 10, with the direction indicated by arrow a in fig. 2 as the forward direction. Wherein, front wheel support 1 includes left front wheel support and right front wheel support, rear wheel support 2 includes left rear wheel support and right rear wheel support, the front wheel connects 3 to connect and connect including left front wheel, the rear wheel connects 4 to connect including right front wheel and right rear wheel, front wheel seat subassembly 5 includes left front wheel seat subassembly and right front wheel seat subassembly, rear wheel seat subassembly 6 includes left rear wheel seat subassembly and right rear wheel seat subassembly, support top connection 7 includes left socle top connection and right socle top connection, push rod bottom connection 9 includes push rod bottom left side connection and push rod bottom right side connection, push rod bottom left side connection rotates to be connected on the left socle top connection, push rod bottom right side connection rotates to be connected on the right socle top connection. The seat post 10 is installed between the left bracket upper joint and the right bracket upper joint.

The front wheel joint 3 is connected between the front wheel support 1 and the front wheel seat assembly 5, the rear wheel joint 4 is connected between the rear wheel support 2 and the rear wheel seat assembly 6, the support upper joint 7 is installed at the tops of the front wheel support 1 and the rear wheel support 2, and the push rod lower joint 9 is installed at the lower end of the push rod 8 and is rotationally connected with the support upper joint 7.

A front wheel orientation assembly 13 capable of orienting the front wheel 11 is arranged between the front wheel connector 3 and the front wheel seat assembly 5, and a rear wheel orientation assembly 14 capable of orienting the rear wheel 12 is arranged between the rear wheel connector 4 and the rear wheel seat assembly 6. The upper joint 7 of the bracket is provided with a front wheel connecting piece 15, a rear wheel connecting piece 16 and a reversing switching piece 17, the front wheel connecting piece 15 is connected with a front wheel orientation component 13, the rear wheel connecting piece 16 is connected with a rear wheel orientation component 14, the lower joint 9 of the push rod can drive the reversing switching piece 17 to simultaneously act on the front wheel connecting piece 15 and the rear wheel connecting piece 16 in the process of rotating forwards and backwards along with the push rod 8, and further the front wheel 11 is in an orientation state and the rear wheel 12 is in a universal state by driving the front wheel orientation component 13 and the rear wheel orientation component 14 to be linked, or the front wheel 11 is in a universal state and the rear wheel 12 is in an orientation state

In the present embodiment, as shown in fig. 1 and 2, in a state where the push rod 8 is rotated backward above the rear wheel frame 2, the rear wheel 12 is in an oriented state and the front wheel 11 is in a universal state, and as shown in fig. 8 and 9, in a state where the push rod 8 is rotated forward above the front wheel frame 1, the front wheel 11 is in an oriented state and the rear wheel 12 is in a universal state

As shown in fig. 3 to 5, the reversing switching member 17 of the present embodiment is transversely movably disposed in the bracket upper joint 7, 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 guiding inclined plane 91 capable of abutting against the outer end surface of the reversing switching member 17, and during the rotation of the push rod lower joint 9, the guiding inclined plane 91 can push the reversing switching member 17 to move inward and further drive the front wheel connecting member 15 and the rear wheel connecting member 16 to move in the up-down direction. In this embodiment, the guiding inclined plane 91 is distributed along the inner periphery of the lower joint 9 of the push rod, the guiding inclined plane 91 is inclined from bottom to top and inwardly in a state that the push rod 8 rotates backwards to a proper position, and the reversing switch member 17 is close to the lower initial section of the guiding inclined plane 91, and in a state that the push rod 8 rotates forwards to a proper position, the upper end section of the guiding inclined plane 91 rotates to the bottom position and the reversing switch member 17 abuts against each other.

In addition, the front wheel connecting piece 15 and the rear wheel connecting piece 16 respectively have the tendency of reverse movement under the action of the elastic piece, and can further push the reversing switching piece 17 to move outwards under the action of the elastic piece. Specifically, a connector mounting box 71 is provided on the inner side of the bracket upper joint 7, the front wheel connector 15 and the rear wheel connector 16 are independently arranged in the connector mounting box 71 in a front-rear side-by-side manner, and the elastic member includes a first spring 18 acting on the front wheel connector 15 and a second spring 19 acting on the rear wheel connector 16. In this embodiment, a first inclined plane 171 and a second inclined plane 172 which are adjacent to each other in the front-rear direction are formed on the inner side surface of the reversing switching member 17, a third inclined plane 151 which is matched with the first inclined plane 171 is formed on the front wheel connecting member 15, a fourth inclined plane 161 which is matched with the second inclined plane 172 is formed on the rear wheel connecting member 16, the first inclined plane 171 and the third inclined plane 151 are both inclined outwards from the top to the bottom, and the second inclined plane 172 and the fourth inclined plane 161 are both inclined inwards from the top to the bottom. The upper end of the first spring 18 abuts against the bottom of the front wheel connecting piece 15, the lower end of the first spring 18 abuts against the bottom of the connecting piece mounting box 71, the upper end of the second spring 19 abuts against the top of the connecting piece mounting box 71, and the lower end of the second spring 19 abuts against the top of the rear wheel connecting piece 16. Thus, the reversing switch member 17 is urged to move outward by the first spring 18 and the second spring 19.

As shown in fig. 2 and 9, the front wheel connecting member 15 is connected to the front wheel alignment assembly 13 through a front wheel cable 20, the rear wheel connecting member 16 is connected to the rear wheel alignment assembly 14 through a rear wheel cable 21, and in a state where the front wheel alignment assembly 13 is pulled upward by the front wheel cable 20 to cause universal rotation of the front wheel 11, the rear wheel cable 21 releases the rear wheel alignment assembly 14 to cause the rear wheel alignment assembly 14 to align the rear wheel 12, and accordingly, in a state where the rear wheel alignment assembly 14 is pulled upward by the rear wheel cable 21 to cause universal rotation of the rear wheel 12, the front wheel cable 20 releases the front wheel alignment assembly 13 to cause the front wheel alignment assembly 13 to align the front wheel 11.

As shown in fig. 6 to 7, the front wheel seat assembly 5 is provided with a front wheel seat mounting hole 52, the front wheel connector 3 is provided with a front wheel connector rotating shaft 31, the front wheel connector rotating shaft 31 is inserted into the front wheel seat mounting hole 52, and the front wheel connector 3 can rotate relative to the front wheel seat assembly 5. Front wheel seat subassembly 5 is last still to be equipped with front wheel locating hole 51, and front wheel locating hole 51 is located the rear side portion of front wheel seat subassembly 5, and front wheel orientation subassembly 13 is including installing front wheel directional spring 131 and the front wheel directional component 132 inside front wheel joint 3, and the lower extreme of front wheel cable 20 is connected on front wheel directional component 132, and front wheel directional component 132 keeps having the trend of downward motion under the effect of front wheel directional spring 131, and front wheel directional component 132 downward motion can insert front wheel 11 and orientate in front wheel locating hole 51.

Similarly, a rear wheel seat mounting hole (not shown) is formed in the rear wheel seat assembly 6, the rear wheel joint 4 has a rear wheel joint rotating shaft (not shown) 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 further provided with a rear wheel positioning hole (not shown), the rear wheel positioning hole is formed in the front side portion of the rear wheel seat assembly 6, the rear wheel orientation assembly 14 comprises a rear wheel orientation spring 141 and a rear wheel orientation piece 142, the rear wheel orientation spring 141 and the rear wheel orientation piece 142 are mounted inside the rear wheel joint 4, the rear wheel inhaul cable 21 is connected to the rear wheel orientation piece 142, the rear wheel orientation piece 142 keeps a downward movement trend under the action of the rear wheel orientation spring 141, and the rear wheel orientation piece 142 can be inserted into the rear wheel positioning hole to orient the rear wheel 12 when moving downward.

The orientation principle of the front wheel and the rear wheel of the universal wheel cart is as follows:

when the push rod 8 rotates to the front side, that is, in the process of rotating from the position shown in fig. 2 to the position shown in fig. 9, the push rod lower joint 9 pushes the reversing switch member 17 to move towards the inner side of the frame 100, the reversing switch member 17 further pushes the front wheel connecting member 15 to move downwards, the front wheel cable 20 is loosened, the front wheel orientation member 132 in the front wheel joint 3 moves downwards under the action of the front wheel orientation spring 131 and is inserted into the front wheel orientation hole 51 of the front wheel seat assembly 5, so as to orient the front wheel seat assembly 5, and the front wheel 11 can only rotate forwards and backwards and cannot rotate universally. Meanwhile, the reversing switching member 17 pushes the rear wheel connecting member 16 to move upward, pulls the rear wheel cable 21, and further drives the rear wheel orienting member 142 to move upward, so that the rear wheel seat assembly 6 can rotate universally.

Conversely, when the push rod 8 rotates to the rear side, that is, when the push rod rotates from the position shown in fig. 2 to the position shown in fig. 9, the front wheel connecting member 15 is returned upward by the first spring 18, and the rear wheel connecting member 16 is returned downward by the second spring 19, so that the reversing switch member 17 is driven to move to the outside of the vehicle frame 100, and the reversing switch member 17 is always kept in contact with the guide slope 91 of the push rod lower joint 9 during the movement. Along with the upward return of the front wheel connecting piece 15, the front wheel guy cable 20 drives the front wheel directional component 132 to move upward and separate from the front wheel seat component 5, so that the front wheel seat component 5 is in a universal rotation state, correspondingly, along with the downward return of the rear wheel connecting piece 16, the rear wheel guy cable 21 is loosened, the rear wheel directional component 142 in the rear wheel joint 4 moves downward 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 component 6, so that the rear wheel seat component 6 is directed, and the rear wheel 12 can only rotate forward and backward but can not rotate universally.

As can be seen from the above operation principle, when the push rod 8 is rotated from the rear side to the front side of the frame 100, i.e., from the position of fig. 2 to the position of fig. 9, the front wheel in fig. 2 becomes the rear wheel in the forward direction of the cart, and the rear wheel in fig. 2 becomes the front wheel in the forward direction of the cart, whereas when the push rod 8 is rotated from the front side to the rear side of the frame 100, i.e., from the position of fig. 9 to the position of fig. 2, the front wheel in fig. 9 becomes the rear wheel in the forward direction, and the rear wheel in fig. 9 becomes the front wheel in the forward direction of the cart. In a word, the front wheel in the advancing direction of the trolley is always in a universal rotating state, and the rear wheel in the advancing direction of the trolley is in an oriented state, so that the trolley is convenient to push.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications or improvements can be made to the present invention without departing from the principle of the present invention, and these are considered to be within the protection scope of the present invention.