CN214729387U - Bicycle dragging device - Google Patents

Abstract

The utility model discloses a bicycle dragging device, which comprises a folding connecting frame and a trolley connecting frame, wherein the front end of the folding connecting frame is clamped on a cart rear connecting shaft and is locked and positioned through a fastening component, the rear end of the folding connecting frame is connected with a hook at the front end of the trolley connecting frame, the rear end of the trolley connecting frame is clamped and connected on a trolley frame, a trolley front wheel is fixedly positioned on the folding connecting frame in a lap joint mode and is not contacted with the ground when in connection, a rotating shaft is arranged on the folding connecting frame, and the rotating shaft is positioned between a cart rear wheel and a trolley front wheel; the folding connecting frame is completely unfolded during working and is folded and placed during non-working. The utility model discloses think about ingenious, compact structure is reasonable, and installation, dismantlement convenient and fast are in the open mode during use, fold when not using and place the rear at the cart back seat, do not influence manned, carry the function of thing, and holistic radius of rotation reduces, folds and deposits convenient and fast, does not influence the safety of riding.

Description

Bicycle dragging device

Technical Field

The utility model relates to a bicycle removes the auxiliary assembly field, especially relates to a bicycle pulls device.

Background

At present, when an adult needs to take a minor to do riding sports outdoors, two bicycles for independent riding are generally required to be connected, so that the riding safety of the minor on roads and other places with certain dangers is ensured. The general connected mode in market at present adopts the connecting rod of arc structure to fix the seat part bracing piece of the cart that the adult ridden and the car head part of the dolly that the minor ridden, realizes connecting the function of pulling. This connection method has the following problems:

1) when the cart turns to, the turning rotation point of dolly also is the locomotive department of cart, therefore the whole radius of turning to of dolly equals approximately to the original radius of turning to of cart plus the length of connecting rod and the length of dolly again, turns to the radius increase, leads to increasing in the danger when the fortune that rides turns to (needs bigger place of turning to, if the cart turns to after, the car of the little man need borrow the lane of next door just can realize turning to, increases the risk of dolly).

2) The connecting rod must be connected to the connecting rod under the saddle of the large vehicle, and in some vehicles, the connecting rod under the saddle is not in enough position, or when an adult does not need a seat as high, the connecting rod cannot provide enough connecting space, and in this case, the connecting rod cannot be used.

3) After the cart arrives at a destination and the cart is separated from the cart, the connecting rod of the cart cannot be retracted, so that the cart drags one connecting rod behind the cart, and the danger behind the cart is increased.

4) The trolley can prevent the trolley head from touching the ground only by firmly fixing the trolley head, and needs to be firmly connected by a more complicated connection mode. The separation can be realized only by using a special tool, and the disassembly and the assembly are inconvenient.

5) After the connecting rod is used, the rear seat part of the cart cannot carry cargo or carry people any more, and the normal use function of the cart is limited.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a bicycle pulls device provides a dismouting more convenient, safer, the richer connected mode of function, solves the problem that the background art lists.

In order to solve the technical problem, the utility model adopts the following technical scheme:

the utility model relates to a bicycle dragging device, including folding link and dolly link, the front end joint of folding link is on big car rear connecting axle and through fastening assembly locking location, the rear end of folding link with the couple of dolly link front end is connected, the rear end of dolly link is connected on the dolly frame in a clamping manner, dolly front wheel overlap joint during connection on the folding link is fixed a position and not contact with the ground, be provided with the rotation axis on the folding link, the rotation axis is located between big car rear wheel and the dolly front wheel; the folding connecting frame is completely unfolded during working and is folded and placed during non-working.

Furthermore, the folding connecting frame comprises a front vehicle positioning connecting frame, a middle connecting frame and a rear supporting connecting rod, the front end of the front vehicle positioning connecting frame is connected with a rear connecting shaft of the large vehicle, the bottom of the rear end of the front vehicle positioning connecting frame is hinged with the front end of the middle connecting frame through a lower connecting plate and a first hinge piece, the rear end of the middle connecting frame is hinged with one end of the rear supporting connecting rod through a rear switching plate and a third hinge piece, and the other end of the rear supporting connecting rod is welded with a hanging ring; the middle part of intermediate junction frame is connected with the support frame, the one end of support frame passes through the lantern ring, the second articulated elements articulates on the intermediate junction frame, the other end of support frame is connected through last fishplate bar the rear end top of front truck location link.

Furthermore, one end of the lower connecting plate is connected to the bottom of the rear end of the front vehicle positioning connecting frame through a fastening bolt and a fastening nut, and the first hinge piece is connected in a circular hole in the other end of the lower connecting plate in a penetrating manner; one end of the upper transfer plate is connected to the top of the rear end of the front vehicle positioning connecting frame through a fastening bolt and a fastening nut, and the top end of the supporting frame is connected to the other end of the upper transfer plate through a connecting screw; the lantern ring is sleeved on the middle connecting frame, and the top of the lantern ring is hinged with the bottom of the supporting frame through the second hinge piece; one end of the rear adapter plate is connected with the bottom of the rear supporting connecting rod through a bolt assembly, the other end of the rear adapter plate is welded on the third hinge piece, and two ends of the third hinge piece are locked and hinged at the rear end of the middle connecting frame through nuts.

Still further, the front end of front truck location link sets up the joint arm of L shape, the junction of joint arm sets up U-shaped joint mouth, U-shaped joint mouth joint is in on the connecting axle behind the cart.

Still further, the trolley connecting frame comprises two connecting main boards which are symmetrically arranged, the hook is arranged at the front end of the connecting main board, the two connecting main boards are fastened by a locking ring after being buckled on a trolley frame, the locking ring is sleeved on the outer side of the connecting main board, and the hook is connected with the hooking ring together; during connection, the front wheel of the trolley is embedded in the middle connecting frame, the rear side of the front wheel of the trolley is lapped on the third hinge piece, and the front side of the front wheel of the trolley is lapped on the vertical connecting rod at the front end of the middle connecting frame.

Furthermore, the locking ring is made of elastic materials and is an elastic ring, or the locking ring is directly locked and positioned by a binding belt with a quick clamp.

Still further, fastening components is including taking handle nut, bowl shape packing ring and interior packing ring, the bilateral symmetry of U-shaped joint mouth is provided with bowl shape packing ring, interior packing ring is installed in inboard bowl shape packing ring inboard, take the outside of the bowl shape packing ring of handle nut installation in the outside and lock and be in on the cart rear connecting axle.

Compared with the prior art, the utility model discloses a beneficial technological effect:

the utility model relates to a bicycle dragging device, which comprises a folding connecting frame and a trolley connecting frame which are connected together in a hanging way, wherein when the bicycle dragging device works, the folding connecting frame is in an open state, the front end of the folding connecting frame is clamped on a rear connecting shaft of a cart and is locked and positioned through a fastening component, and the rear end of the trolley connecting frame is clamped and connected on a frame of the trolley; the folding placement is carried out when the folding type clothes hanger is not in work. Folding joint frame includes preceding car location link, intermediate junction frame, back supporting connecting rod and the support frame of location usefulness, adopts the rotatable linking together of a plurality of articulated elements between the support body, and the bolt assembly fastening installation convenient to detach is adopted more to fixed one end of usefulness, and convenient to use is swift, and the installation is dismantled conveniently.

1) The utility model discloses connecting axle behind the cart is connected to folding joint frame during use, holds the wheel of dolly through intermediate junction frame, connects the mainboard lock and passes through the locking ring fastening after on the dolly frame, and folding operation both can be realized to intermediate junction frame and front truck positioning connection frame's junction, also can rotate around coaxial fastening screw, and the rotation axis design of dolly has reduced turning radius greatly in the dead ahead of dolly wheel promptly.

2) The connection point of the folding connection frame is arranged at the rear connection shaft of the cart, and the structure and the height of the saddle of the cart are not limited.

3) The trolley adopts a hanging ring for supporting wheels and hanging the rear support connecting rod for connection, the connection is pressed by gravity, and when the trolley is separated, the trolley head can be lifted to separate the wheels without using any tool.

4) The connecting point is arranged at the rear connecting shaft of the cart, so that the use of a rear frame of the cart is not influenced.

5) After the trolley is separated from the cart, the folding connecting frame can be folded and retracted, so that the influence on the cart is reduced, and the safety of the cart is improved; the trolley connecting frame can be arranged in a bag for storage after being detached, and riding is not influenced;

6) when the bicycle dragging device is not used, the bicycle dragging device is folded to be parallel to a bicycle body, and then the bicycle dragging device can be converted into a rear frame to realize a loading function for a large bicycle without the rear frame.

Generally speaking, the utility model discloses think about ingenious, compact structure is reasonable, installation, dismantlement convenient and fast are in the open mode during use, fold when not using and place the rear at the cart back seat, do not influence manned, carry the function of thing, holistic radius of rotation reduces, folds and deposits convenient and fast, does not influence the safety of riding.

Drawings

The present invention will be further explained with reference to the following description of the drawings.

FIG. 1 is a schematic structural view of a bicycle towing device of the present invention; (expanded state)

FIG. 2 is a schematic view of the bicycle towing device of the present invention in a folded state;

FIG. 3 is a front view of the utility model connected with a cart;

FIG. 4 is a side view of the utility model in connection with a cart;

FIG. 5 is a schematic view of the connection between the present invention and the frame of the cart;

FIG. 6 is a schematic view of the connection state of the present invention during operation;

FIG. 7 is a schematic view of the positioning principle of the cart rear connecting shaft of the present invention;

description of reference numerals: 1. folding the connecting frame; 101. a front vehicle positioning connecting frame; 102. an upper transfer plate; 103. Fastening a nut; 104. fastening a bolt; 105. a lower tapping plate; 106. an intermediate connecting frame; 107. a first hinge member; 108. a support frame; 109. a connecting screw; 110. a collar; 111. a second hinge member; 112. a rear adapter plate; 113. a third hinge member; 114. a rear support link; 115. a bolt assembly; 116. hanging and connecting rings; 117. a clamping arm;

2. a trolley connecting frame; 201. connecting the main board; 202. hooking; 203. locking a ring;

3. a cart rear connecting shaft; 4. a handled nut; 5. a bowl-shaped gasket; 6. an inner gasket; 7. a trolley frame.

Detailed Description

As shown in fig. 1-7, a bicycle dragging device comprises a folding connection frame 1 and a trolley connection frame 2, wherein the front end of the folding connection frame 1 is clamped on a cart rear connection shaft 3 and is locked and positioned through a fastening component, the rear end of the folding connection frame 1 is connected with a hook 202 at the front end of the trolley connection frame 2, the rear end of the trolley connection frame 2 is clamped and connected on a trolley frame 7, a trolley front wheel is lapped on the folding connection frame 1 to be fixedly positioned and is not contacted with the ground when in connection, a rotating shaft is arranged on the folding connection frame 1, and the rotating shaft is positioned between a cart rear wheel and a trolley front wheel; the folding connecting frame 1 is completely unfolded in working and is folded and placed in non-working.

Specifically, as shown in fig. 1 and 2, the folding connecting frame 1 includes a front car positioning connecting frame 101, an intermediate connecting frame 106 and a rear supporting connecting rod 114, the front end of the front car positioning connecting frame 101 is connected with the rear connecting shaft 3 of the cart, the bottom of the rear end of the front car positioning connecting frame 101 is hinged to the front end of the intermediate connecting frame 106 through a lower connecting plate 105 and a first hinge 107, the rear end of the intermediate connecting frame 106 is hinged to one end of the rear supporting connecting rod 114 through a rear adapter plate 112 and a third hinge 113, and the other end of the rear supporting connecting rod 114 is welded with a hanging ring 116; the middle of the middle connecting frame 106 is connected with a supporting frame 108, one end of the supporting frame 108 is hinged to the middle connecting frame 106 through a lantern ring 110 and a second hinge part 111, and the other end of the supporting frame 108 is connected to the top of the rear end of the front vehicle positioning connecting frame 101 through an upper connecting plate 102.

Specifically, one end of the lower connecting plate 105 is connected to the bottom of the rear end of the front vehicle positioning connecting frame 101 through a fastening bolt 104 and a fastening nut 103, the first hinge 107 is connected in a circular hole at the other end of the lower connecting plate 105 in a penetrating manner, the middle connecting frame 106 rotates upwards by 90 degrees around the first hinge 107 during folding, and is placed in parallel with the vertical plate at the rear end of the front vehicle positioning connecting frame 101; one end of the upper connection plate 102 is connected to the top of the rear end of the front vehicle positioning connection frame 101 through a fastening bolt 104 and a fastening nut 103, the top end of the support frame 108 is connected to the other end of the upper connection plate 102 through a connection screw 109, the collar 110 is sleeved on the middle connection frame 106, the top of the collar 110 is hinged to the bottom of the support frame 108 through the second hinge 111, when the middle connection frame 106 is rotated upwards and folded, the connection screw 109 is detached to separate the support frame 108 from the upper connection plate 102, and the support frame 108 is rotated around the second hinge 111 and then is close to the middle connection frame 106 and placed in a parallel state with the middle connection frame 106; the one end of back keysets 112 pass through bolt assembly 115 with the bottom of back supporting rod 114 links together, the other end welding of back keysets 112 is in on the third hinge 113, the both ends of third hinge 113 are passed through and are articulated after the nut locking the rear end of intermediate junction frame 106, when not using, back supporting rod 114 is rotatory folding to the inboard around third hinge 113, and folding back and intermediate junction frame 106 keep parallel state. Specifically, after the folding connecting frame 1 is folded, the middle connecting frame 106, the supporting frame 108 and the rear supporting link 114 are all vertically placed. In addition, the upper connecting plate 102 and the lower connecting plate 105 are connected to the front vehicle positioning connecting frame 101 through coaxial fastening bolts 104, and the intermediate connecting frame 106 can rotate around the axis of the fastening bolt 104, which is the rotating shaft of the folding connecting frame, of the fastening bolt 104.

Specifically, the front end of front truck positioning connecting frame sets up the joint arm 117 of L shape, the junction of joint arm 117 sets up U-shaped joint mouth, U-shaped joint mouth joint is in on the connecting axle behind the cart.

Specifically, as shown in fig. 1 and 5, the trolley connecting frame 2 includes two connecting main boards 201 symmetrically arranged, the hook 202 is disposed at the front end of the connecting main board 201, the two connecting main boards 201 are fastened by a locking ring 203 after being fastened on the trolley frame 7, the locking ring 203 is sleeved on the outer side of the connecting main board 201, and the hook 202 is connected with the hooking ring 116. The locking ring is made of elastic materials and is an elastic ring, or the locking ring is directly locked and positioned by a binding belt with a quick clamp. During connection, the front wheel of the trolley is embedded in the middle connecting frame 106, the rear side of the front wheel of the trolley is lapped on the third hinge part 113, and the front side of the front wheel of the trolley is lapped on the vertical connecting rod at the front end of the middle connecting frame 106.

Specifically, as shown in fig. 3 and 4, the fastening assembly comprises a handle nut 4, a bowl-shaped gasket 5 and an inner gasket 6, the bowl-shaped gaskets 5 are symmetrically arranged on two sides of the U-shaped clamping opening, the inner gasket 6 is arranged on the inner side of the bowl-shaped gasket, and the handle nut 4 is arranged on the outer side of the bowl-shaped gasket and locked on the cart rear connecting shaft 3. Specifically, the handle-equipped nut 4 comprises an integrally formed handle end and a fastening end, and the fastening end is of a nut structure and is screwed and connected to the cart rear connecting shaft 3. The nut 4 with the handle is used for manually rotating the fastening end through the handle end without using tools to push the bowl-shaped gasket 5 to clamp the clamping arm 117, the bowl-shaped gasket 5 is elastically deformed at the fastening end, and the clamping arm 117 can be clamped only by small clamping force, so that the nut does not fall off the cart rear connecting shaft 3 due to bumping in the moving process; meanwhile, under the condition that the nut 4 with the handle is not required to be adjusted, the clamping arm 117 and the fastening component can rotate around the cart rear connecting shaft 3 under the action of common human power, and the folding function of the bicycle dragging device is realized.

As shown in fig. 6, the working principle of the present invention is as follows:

firstly, the bicycle dragging device of the utility model is completely assembled, the front bicycle positioning connecting frame 101, the middle connecting frame 106, the rear supporting connecting rod 114 and the positioning supporting frame 108 are assembled together through a plurality of different articulated elements and adapter plates, then the clamping arm 117 at the front end of the front bicycle positioning connecting frame 101 is connected with the cart rear connecting shaft 3, and is locked and fixed through the fastener of the handle-mounted nut 4, the bowl-shaped gasket 5 and the inner gasket 6; then, the two connection main boards 201 are fastened to the cart frame 7 by the locking ring 203, and finally the hook 202 is hooked to the hooking ring 116 at the rear end of the folding connection frame 1, thereby realizing the connection between the cart and the cart, and the connected state is as shown in fig. 6.

Wherein: 1) the point A is a connecting point of the bicycle dragging device and the cart rear connecting shaft 3; the point B and the point C are respectively connecting points of the upper connecting plate and the lower connecting plate, and the point D is the position of the second hinge piece 111;

2) point F is the point of connection of the bicycle towing device to the trolley frame 7;

3) point H is the transverse axis on the intermediate link 106, point E is the third hinge 113, and the connected front wheels of the cart are supported and positioned on the transverse axis at point H and the third hinge 113 to limit the wheels of the cart from moving downward relative to point H and point E;

4) points G1 and G2 respectively represent the points of contact of the cart and cart wheels with the horizontal line of the ground;

through analysis, the following results are obtained:

1) wherein A, B, C points form a triangle, B, C, D points form a triangle, and the two triangular lines are connected together to form a whole body rotating around the point A; C. segment E is an extension of segment C, D, and thus constitutes a virtual segment AE, which rotates about point A;

2) the front wheel of the trolley is limited by a point H and a point E under the action of gravity, so that an included angle AEF formed by a line segment CE and a line segment EF cannot be reduced, and the distance between the point A and the point F cannot be reduced, thereby actually forming a triangle delta AEF capable of rotating around the point A;

3) the trolley with the head lifted as a whole forms a line segment FG2 which can rotate around a point G2;

4) as described above, the angle of ≈ AEF does not become small, and therefore the relative distance from the point E to the point G2 does not change, thereby forming a triangle Δ FEG2 rotatable about the point G2;

5) Δ AEF and Δ FEG2 share a line segment EF, so the two triangles are connected together, the distance from point a to point G1 is a fixed radius of the wheels of the cart, point G2 has already contacted the ground, angle G1G2A does not change, therefore, the front wheels of the cart attached to the combination of point a to point G2 do not move up or down under the action of gravity, so the front wheels of the cart can be lifted off the ground, only the rear wheels of the cart can be grounded, and when a person on the cart steps on the pedal, power can be provided;

6) the width of the middle connecting frame 106 of the point H and the point E and the width of the point F shaft are reasonably designed to fix the wheels or the frame of the trolley, so that the trolley is prevented from moving transversely and can be firmly fixed on the bicycle dragging device, and the stability in the running process is kept; the front wheel of the trolley is connected with the head of the trolley, so that the head can not rotate any more;

7) after the cart is steered, the trolley can rotate around the axis formed by the point B and the point C, the trolley and the cart form a certain included angle, and the steering axis of the trolley is the point BC instead of the steering axis of the cart head; thereby effectively shortening the radius of rotation.

Specifically, as shown in fig. 7, a schematic diagram of the connection between the clamping arm 117 at the front end of the front positioning connecting frame 101 and the cart rear connecting shaft 3 is shown, wherein the dotted line represented by X is parallel to the ground, the dotted line represented by Y is perpendicular to the ground, and the direction represented by M may be any direction forming an angle of 0-90 degrees with the Y axis (in the second quadrant direction formed by the X axis and the Y axis); the connecting end of the clamping arm 117 comprises an open slot, which comprises characteristic arcs at the bottom of the slot, two adjacent sides of the open slot, and two sections of outer arcs at the opening of the slot;

the two sections of outer arcs are used for guiding when a cart axle is hung, the two sides of the opening are parallel to the direction M and larger than the outer dimension of the cart rear connecting shaft 3, and the characteristic arcs at the bottom of the groove are arcs larger than the cart rear connecting shaft 3 and are smoothly connected with the two sides of the opening;

when the clamping arm 117 is sleeved in the cart rear connecting shaft 3 through the open slot, the cart rear connecting shaft 3 is limited in the semicircle of the characteristic arc at the bottom of the slot, so that a downward force F can be generated due to the weight of the cart, but the opening direction of the open slot is M direction, and the force generated by dragging the cart when the cart moves forwards is respectively F1 and F2, so that the clamping arm 117 can not fall off upwards when being pressed on the axle.

When the folding link 1 is in the folded state (parallel to the ground as described above), i.e., the X-axis becomes perpendicular to the ground, a component F1 exists due to the opening in the M-direction, so that the snap arm 117 does not fall off the rear wheel of the cart.

The joint of the clamping arm 117 and the front vehicle positioning connecting frame 101 is a straight arm, a certain distance is reserved along the Y-axis direction, and the straight arm is connected and transited by a great arc, and a clearance avoiding position is formed at the great arc and is used for avoiding a part of a transmission or other characteristics of the rear wheels of the large vehicle near the rear connecting shaft 3 of the large vehicle.

Furthermore, the designated connection point with the cart and the trolley can be other points as long as the corresponding function can be achieved. Such as: the trolley is fixed with a wheel rotating shaft, can also be a front axle part of the trolley or any part on a bogie, and can also be a tripod point fixed by the trolley or any part of a tripod or a trolley body. Similar functionality can be achieved by local modifications, increasing or decreasing the number of attachment points in the middle of the bicycle towing device.

The above-mentioned embodiments are only intended to describe the preferred embodiments of the present invention, but not to limit the scope of the present invention, and those skilled in the art should also be able to make various modifications and improvements to the technical solution of the present invention without departing from the spirit of the present invention, and all such modifications and improvements are intended to fall within the scope of the present invention as defined in the appended claims.

Claims (7)

1. A bicycle towing device, characterized in that: the foldable trolley comprises a foldable connecting frame and a trolley connecting frame, wherein the front end of the foldable connecting frame is clamped on a rear connecting shaft of a trolley and is locked and positioned through a fastening assembly, the rear end of the foldable connecting frame is connected with a hook at the front end of the trolley connecting frame, the rear end of the trolley connecting frame is clamped and connected on a trolley frame, a front wheel of the trolley is fixedly positioned on the foldable connecting frame in a lap joint mode and is not in contact with the ground when in connection, a rotating shaft is arranged on the foldable connecting frame, and the rotating shaft is positioned between a rear wheel of the trolley and a front wheel of the trolley; the folding connecting frame is completely unfolded during working and is folded and placed during non-working.

2. The bicycle towing device according to claim 1, wherein: the folding connecting frame comprises a front vehicle positioning connecting frame, a middle connecting frame and a rear supporting connecting rod, the front end of the front vehicle positioning connecting frame is connected with a rear connecting shaft of the cart, the bottom of the rear end of the front vehicle positioning connecting frame is hinged with the front end of the middle connecting frame through a lower connecting plate and a first hinge piece, the rear end of the middle connecting frame is hinged with one end of the rear supporting connecting rod through a rear adapter plate and a third hinge piece, and the other end of the rear supporting connecting rod is welded with a hanging ring; the middle part of intermediate junction frame is connected with the support frame, the one end of support frame passes through the lantern ring, the second articulated elements articulates on the intermediate junction frame, the other end of support frame is connected through last fishplate bar the rear end top of front truck location link.

3. The bicycle towing device according to claim 2, wherein: one end of the lower connecting plate is connected to the bottom of the rear end of the front vehicle positioning connecting frame through a fastening bolt and a fastening nut, and the first hinge piece penetrates through a round hole in the other end of the lower connecting plate; one end of the upper transfer plate is connected to the top of the rear end of the front vehicle positioning connecting frame through a fastening bolt and a fastening nut, and the top end of the supporting frame is connected to the other end of the upper transfer plate through a connecting screw; the lantern ring is sleeved on the middle connecting frame, and the top of the lantern ring is hinged with the bottom of the supporting frame through the second hinge piece; one end of the rear adapter plate is connected with the bottom of the rear supporting connecting rod through a bolt assembly, the other end of the rear adapter plate is welded on the third hinge piece, and two ends of the third hinge piece are locked and hinged at the rear end of the middle connecting frame through nuts.

4. The bicycle towing device according to claim 2, wherein: the front end of the front vehicle positioning connecting frame is provided with an L-shaped clamping arm, a U-shaped clamping interface is arranged at the joint of the clamping arm, and the U-shaped clamping interface is clamped on the rear connecting shaft of the cart.

5. The bicycle towing device according to claim 2, wherein: the trolley connecting frame comprises two connecting main boards which are symmetrically arranged, the hook is arranged at the front end of the connecting main board, the two connecting main boards are fastened by a locking ring after being buckled on a trolley frame, the locking ring is sleeved on the outer side of the connecting main boards, and the hook is connected with the hanging ring; during connection, the front wheel of the trolley is embedded in the middle connecting frame, the rear side of the front wheel of the trolley is lapped on the third hinge piece, and the front side of the front wheel of the trolley is lapped on the vertical connecting rod at the front end of the middle connecting frame.

6. The bicycle towing device according to claim 5, wherein: the locking ring is made of elastic materials and is an elastic ring, or the locking ring is directly locked and positioned by a binding belt with a quick clamp.

7. The bicycle towing device according to claim 4 wherein: the fastening assembly comprises a handle nut, a bowl-shaped gasket and an inner gasket, the bowl-shaped gaskets are symmetrically arranged on two sides of the U-shaped clamping port, the inner gasket is arranged on the inner side of the bowl-shaped gasket, and the handle nut is arranged on the outer side of the bowl-shaped gasket and locked on the cart rear connecting shaft.

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