A linked folding trolley

Abstract

The application discloses a linkage folding trolley, which comprises a trolley frame and a trolley linkage assembly. The trolley frame has a front leg group, a rear leg group and a foldable handle, which are rotatably connected through a joint structure. The joint structure is locked through the plug-in cooperation of a plug and a socket. A traction rope is arranged between the handle and the joint structure. When the handle is folded, the traction rope pulls a rotating part in the joint structure to rotate. The rotating part is lifted through the cooperation of an inclined surface and a movable button to make the plug exit the socket, thereby unlocking the trolley frame. The trolley linkage assembly comprises a linkage part, a traction part and a seat connecting part. After the trolley frame is unlocked, the handle and the seat part assembly can be pressed down to complete the linkage folding in one step. After the handle is folded, the outer extension part is eliminated, and the folded trolley frame is compact and can be stably placed. The application integrates the folding of the handle, the unlocking of the joint and the linkage folding into one, and has a simple structure and convenient operation.

Description

Technical Field

[0001] This invention relates to the field of stroller technology, and in particular to a stroller with a folding mechanism, which is especially suitable for baby strollers, children's strollers and other children's stroller products. Background Technology

[0002] A typical handcart frame consists of a front leg assembly, a rear leg assembly, and a handlebar. The upper ends of the front leg assembly, the upper ends of the rear leg assembly, and the lower ends of the handlebar are often connected at the same joint structure, which is locked in the unfolded state by a locking mechanism within the joint structure. The existing frame folding function design has the following main shortcomings.

[0003] Firstly, some frames do not have a linkage folding function, requiring each component to be operated independently when folding, which is complicated; moreover, after folding, there is no reliable constraint between the components, the whole is loose and cannot be placed upright, and it will unfold on its own when the front and rear wheels touch the ground, making storage and carrying extremely inconvenient.

[0004] Secondly, while some frames have a linked retraction function, they rely on numerous multi-link mechanisms to transmit motion between components. This results in a large number of parts, complex structure, and high manufacturing costs. Furthermore, the excessive number of hinge points leads to large cumulative clearances, affecting transmission accuracy and retraction tightness. In addition, to prevent the front and rear leg assemblies from over-extending, additional limiting links are required, further increasing the system's complexity.

[0005] Thirdly, in existing technologies, handlebars are typically a single, non-foldable, one-piece long pole. When the frame is folded, because the handlebar length remains fixed, although its lower end folds in with the joint structure, the upper end (the grip section) protrudes significantly beyond the folded front and rear legs. This results in a high center of gravity and a large space occupation when the folded vehicle is standing upright. Furthermore, the protruding handlebar is prone to collisions or snagging with other items, affecting the neatness of storage and ease of carrying. To address this issue, some existing handcarts have foldable handlebars. However, these designs only focus on shortening the handlebar length; the folding action is independent of the frame folding action. Users must first fold the handlebars, then separately operate the joint structure to unlock and fold the frame. The folding process still requires multiple steps, failing to optimize the overall smoothness and convenience of the folding operation.

[0006] Therefore, how to further eliminate the problem of the handlebars sticking out after folding while retaining the linkage folding function, and organically integrate the handlebar folding action with the frame unlocking and linkage folding action to achieve a simpler and more efficient one-step folding operation, while maintaining the advantages of a streamlined structure, fewer parts, and lower cost, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The main objective of this invention is to propose a trolley with a linked folding mechanism. This invention addresses the shortcomings of existing trolleys where the handlebars protrude beyond the front and rear legs after folding, affecting storage and stability, and the cumbersome operation caused by the independent folding and folding mechanisms of existing handlebars. The invention provides a trolley where the handlebars can be folded during folding, and the folding action simultaneously triggers the unlocking of the joint structure. This integrates handlebar folding, joint unlocking, and linked folding into a single process. During folding, the folding of the handlebars smoothly unlocks the entire frame, allowing for continuous folding. This results in a compact frame with no protruding parts after folding, ensuring stable upright placement, and simplifying the operation.

[0008] To achieve the above objectives, the present invention proposes a linked retractable bicycle, comprising a frame, the frame having a front leg assembly, a rear leg assembly, and handlebars, wherein the front leg assembly, the rear leg assembly, and the handlebars are rotatably connected via a common joint structure, the joint structure having a locked state and an unlocked state; in the locked state, the three components are relatively fixed, and in the unlocked state, the three components can rotate relative to each other.

[0009] The handlebars are foldable handlebars;

[0010] The trolley also includes a tow rope, which is connected between the handle and the joint structure. When the handle is folded, the tow rope drives the joint structure to switch from the locked state to the unlocked state.

[0011] The handcart also includes a frame linkage assembly, which is installed on the frame and is used to achieve linkage folding of the cart by pressing down the handle and seat assembly after the joint structure is unlocked;

[0012] The frame linkage assembly includes:

[0013] The linkage has a first end and a second end. The first end is movably engaged with a first guide portion disposed on the rear leg assembly and can reciprocate along the first guide portion. The second end is hinged to the front leg assembly.

[0014] The traction component has a third end and a fourth end, the third end being hinged to the first end of the linkage component, and the fourth end being hinged to the handlebars;

[0015] The seat connector is hinged to the frame and is used to connect to the seat assembly. The seat connector is provided with a guide clearance part, and the second end of the linkage part is also movably engaged with the guide clearance part.

[0016] Preferably, the first guide portion is a straight strip hole, and the first end of the linkage is provided with a first mating portion, which extends into the first guide portion and can slide along it.

[0017] Preferably, the first guide portion has a first aperture section and a second aperture section along its through direction, the inner diameter of the first aperture section is smaller than the inner diameter of the second aperture section, the first mating portion passes through the first aperture section and the second aperture section, and the outer diameter of the first mating portion is smaller than the inner diameter of the first aperture section, and a first limiting head is provided at the part of the first mating portion located in the second aperture section, the outer diameter of the first limiting head is smaller than the inner diameter of the second aperture section and larger than the inner diameter of the first aperture section.

[0018] Preferably, the guide clearance portion is an arc-shaped slot, and the second end of the linkage is provided with a second mating portion, which extends into the guide clearance portion and can slide along it.

[0019] Preferably, the guide clearance portion has a third aperture segment and a fourth aperture segment along its through direction, the inner diameter of the third aperture segment is smaller than the inner diameter of the fourth aperture segment, the second mating portion passes through the third aperture segment and the fourth aperture segment, and the outer diameter of the second mating portion is smaller than the inner diameter of the third aperture segment, and a second limiting head is provided at the part of the second mating portion located in the fourth aperture segment, the outer diameter of the second limiting head is smaller than the inner diameter of the fourth aperture segment and larger than the inner diameter of the third aperture segment.

[0020] Preferably, the seat connector has a fifth end, which is used to movably engage with a second guide portion disposed on the front foot assembly and can reciprocate along the second guide portion.

[0021] Preferably, the guide clearance portion is an arc-shaped strip hole provided on the seat connector, and the second guide portion is an arc-shaped strip hole provided on the front foot assembly. When the frame is in the unfolded use state, the guide clearance portion is located above the second guide portion, and the concave arc sides of the two are opposite to each other and the convex arc sides are opposite to each other.

[0022] Preferably, the fifth end is provided with a third mating part, the third mating part extends into the second guide part and can slide along it, and the third mating part and the second guide part are in clearance fit, so that the fifth end can slide along the second guide part and rotate relative to it.

[0023] Preferably, the second guide portion has a fifth aperture segment and a sixth aperture segment along its through direction, the inner diameter of the fifth aperture segment is smaller than the inner diameter of the sixth aperture segment, the third mating portion passes through the fifth aperture segment and the sixth aperture segment, and the outer diameter of the third mating portion is smaller than the inner diameter of the fifth aperture segment, and the portion of the third mating portion located in the sixth aperture segment is provided with a third limiting head, the outer diameter of the third limiting head is smaller than the inner diameter of the sixth aperture segment and larger than the inner diameter of the fifth aperture segment.

[0024] Preferably, the fourth end is used to hinge with a follower part disposed on the handlebar.

[0025] Preferably, the joint structure has a socket, the joint structure has a movable button, the movable button has a plug, the movable button can move relative to the joint structure, so that the plug can be inserted into or out of the socket to form the locked state and the unlocked state. Under normal conditions, the movable button is subjected to the biasing force of the tension spring to keep the plug inserted in the socket.

[0026] The joint structure also includes a rotating component. The traction rope is connected between the handlebar and the rotating component. When the handlebar is folded, the rotating component is pulled to rotate by the traction rope. The rotating component and the movable button are provided with a beveled engagement structure. When the rotating component rotates, the movable button is pushed by the beveled engagement structure to overcome the bias force of the tension spring, so that the plug-in is disengaged from the socket.

[0027] A reset spring is also provided, which applies an elastic force to the rotating component to automatically reset it.

[0028] The handcart provided by this invention, through the coordinated arrangement of linkage components, traction components and seat connectors, only requires three main components to simultaneously realize the linkage folding of the handle, rear leg assembly, front leg assembly and seat assembly. It eliminates the need for multiple independent linkage mechanisms and limiting linkages, greatly reducing the number of parts and hinge points, lowering manufacturing costs and assembly difficulty, and reducing cumulative fit clearance, making the linkage action smoother and more reliable.

[0029] More importantly, this invention features a foldable handlebar and a traction rope between the handlebar and the joint structure. This allows the user's folding action to simultaneously pull the rotating components within the joint structure. The inclined surface mechanism then lifts the movable button, disengaging the insert and automatically unlocking the joint. Simultaneously, the overall frame lock is released, allowing the user to continue pressing down and directly initiate the folding process. The handlebar folding, joint unlocking, and folding actions are integrated into one process, eliminating the need for separate steps and significantly improving folding convenience and efficiency. Furthermore, the folded handlebar eliminates the problem of protruding handlebars in traditional handcarts, resulting in a more compact and neat folded shape. When standing upright, the center of gravity is lower, it occupies less space, and there is no risk of snagging or collision due to protruding handlebars, significantly improving storage and portability.

[0030] Furthermore, the design of the fourth end of the traction component and the handlebar hinge point being located at a critical position ensures that the frame can stand stably after folding without accidentally opening. The linkage component, in the unfolded state, also functions as a limiter to prevent the front and rear leg assemblies from over-expanding, eliminating the need for additional limit linkages. The seat connector, through its hinge with the frame and the cooperation between the second end of the linkage component and the guide clearance part, forms a dual-point support in the unfolded state, ensuring the load-bearing stability of the seat assembly. Overall, this invention achieves a high degree of integration of multiple functions with minimal components, including simultaneous handlebar folding and unlocking, linked folding, unfolding limit, prevention of accidental unfolding during folding, and stable seat support. It has a compact structure, is easy to operate, and possesses good practical value and market potential. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the handcart frame in its unfolded state.

[0032] Figure 2 for Figure 1 A sectional view;

[0033] Figure 3 This is a diagram illustrating the process of folding up the handcart frame.

[0034] Figure 4 for Figure 3 A sectional view;

[0035] Figure 5 A schematic diagram showing the handcart frame in its folded-down state;

[0036] Figure 6 for Figure 5 A sectional view;

[0037] Figure 7 This is an assembly diagram of the frame linkage assembly and the handcart frame;

[0038] Figure 8 for Figure 7 A partial exploded view;

[0039] Figure 9 This is a diagram showing the handlebars folded.

[0040] Figure 10 This is a partial exploded view of the joint structure;

[0041] Figure 11 This is a schematic diagram of the rotating parts and the housing of the joint structure. Detailed Implementation

[0042] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0044] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0045] It should be noted in advance that, in this specific embodiment section, the structures, shapes, materials, dimensions, and specific connection methods between components (such as threaded connections, welding, riveting, snap-fit ​​connections, interference fits, and other conventional connection methods) not further described in detail are all content that can be directly understood and implemented by those skilled in the art based on their common knowledge and existing technology. The core of this invention lies in the positional, fitting, and kinematic relationships between the constituent components, rather than the microstructure or material of a specific component itself. Therefore, for the conventional technical details not elaborated above, those skilled in the art can fully implement the technical solution of this invention without creative effort by referring to the overall description in this specification and combining it with common knowledge in the field, without having to exhaustively limit the specific shape, size, or material of each component. The disclosure of this invention has reached the level that enables those skilled in the art to implement it, and the omission of the above-mentioned conventional technical details will not result in insufficient disclosure.

[0046] Example 1

[0047] This embodiment specifically illustrates the basic structure of a vehicle frame linkage assembly.

[0048] like Figures 1 to 8 As shown, this embodiment provides a frame linkage assembly for a handcart frame.

[0049] The cart frame has a front leg assembly 100, a rear leg assembly 200 and a handlebar 300. The upper ends of the front leg assembly 100, the upper ends of the rear leg assembly 200 and the lower ends of the handlebar 300 are rotatably connected by the same joint mechanism 400.

[0050] The joint mechanism 400 has a locking mechanism inside, which has a locked state and an unlocked state.

[0051] In the locked state, the front leg assembly 100, the rear leg assembly 200 and the handlebars 300 are fixed relative to each other, and the frame remains in the unfolded use state.

[0052] In the unlocked state, the front foot assembly 100, the rear foot assembly 200, and the handlebars 300 can rotate relative to each other around the joint mechanism 400 to perform the actions of folding or unfolding the bike.

[0053] The frame linkage assembly includes a linkage component 1, a traction component 2, and a seat connector 3.

[0054] Linkage component 1 is an elongated component with a first end 11 and a second end 12;

[0055] The first end 11 of the linkage 1 is used to engage with the first guide 01 provided on the rear foot assembly 200, and can reciprocate along the first guide 01;

[0056] The second end 12 of the linkage 1 is used to hinge with the front foot assembly 100. The linkage 1 plays a key role in motion transmission and limiting in the frame.

[0057] The traction component 2 is an elongated member with a third end 21 and a fourth end 22;

[0058] The third end 21 of the traction member 2 is hinged to the first end 11 of the linkage member 1, and the fourth end 22 of the traction member 2 is used to hinge to the handlebar 300. The traction member 2 is used to transmit the swing motion of the handlebar 300 to the linkage member 1, thereby driving the rear foot assembly 200 to move.

[0059] The seat connector 3 is used to hinge with the vehicle frame, and the seat connector 3 is provided with a guide clearance part 31;

[0060] The second end 12 of the linkage 1 also cooperates with the guide and avoidance part 31.

[0061] The seat connector 3 is used to install the seat assembly 500 (such as a seat, bassinet, etc.) and swings together with the seat assembly 500 during the folding process;

[0062] Of course, in one embodiment, the seat connector 3 does not need to be installed with the seat assembly 500; the seat connector 3 itself is the seat assembly 500 (such as a seat, bassinet, etc.).

[0063] The working principle is as follows:

[0064] When the user needs to put the vehicle away, first release the locking of the joint mechanism 400 so that the front foot assembly 100, the rear foot assembly 200 and the handlebars 300 can rotate relative to each other.

[0065] Subsequently, the user presses down the seat assembly 500 (or the direct press seat connector 3) and the handlebars 300;

[0066] The seat assembly 500 has its lower edge close to the front foot assembly 100, and the handlebars 300 have their lower edge close to the rear foot assembly 200.

[0067] The seat connector 3 swings together with the seat assembly 500. The guide clearance part 31 on the seat connector 3 provides clearance space for the second end 12 of the linkage 1, so that the seat connector 3 can move smoothly without interference.

[0068] At the same time, the swing of the handlebars 300 is transmitted to the linkage 1 through the traction member 2. The first end 11 of the linkage 1 slides along the first guide part 01, thereby driving the rear foot assembly 200 to swing in the retraction direction.

[0069] The lower part of the seat assembly 500 indirectly applies force to the front leg assembly 100 through the cooperation of the seat connector 3 and the guide avoidance part 31 with the second end 12 of the linkage 1, causing the front leg assembly 100 to swing in the retraction direction.

[0070] Finally, the front foot assembly 100 and the rear foot assembly 200 move closer to each other, the seat assembly 500 moves closer to the front foot assembly 100, and the handlebars 300 move closer to the rear foot assembly 200, at which point the frame enters the folded-down state.

[0071] This embodiment achieves multi-directional linkage retraction function of handlebars 300, rear leg assembly 200 and seat assembly 500 (including front leg assembly 100) with a very small number of parts through the cooperation of three core components: linkage component 1, traction component 2 and seat connector 3. The structure is greatly simplified, the assembly is simple and the cost is low.

[0072] In addition, in this embodiment, the linkage 1 also has the function of limiting the excessive unfolding of the front leg assembly 100 and the rear leg assembly 200 when the frame is in the unfolded use state.

[0073] Specifically, such as Figure 2As shown, when the frame is unfolded into place, the first end 11 of the linkage 1 is located at the corresponding position of the first guide part 01, and the second end 12 of the linkage 1 is hinged to the front leg assembly 100 and cooperates with the guide avoidance part 31. The length of the linkage 1 itself and the position of the hinge point together restrict the front leg assembly 100 and the rear leg assembly 200 from continuing to rotate outward, thereby playing a safety limiting role in preventing over-extension, without the need to set up an additional independent limiting link.

[0074] In addition, such as Figure 6 In the folded state shown, if force is applied directly to the rear leg assembly 200 to attempt to unfold the frame, the first end 11 of the linkage 1 will be subjected to force and attempt to slide along the first guide portion 01. However, because the fourth end 22 of the traction member 2 is above the third end 21, the relative angle and position between the two cause the fourth end 22 to restrict the position of the third end 21. That is, in the folded state, the fourth end 22 restricts the degree of freedom of movement of the third end 21 along the first guide portion 01, preventing the first end 11 of the linkage 1 from sliding along the first guide portion 01. The entire mechanism is stuck, and the rear leg assembly 200 cannot unfold. Conversely, if the handlebars 300 are raised first, the fourth end 22 of the traction member 2 moves with the handlebars 300 first. The traction member 2 pulls the third end 21, thereby causing the first end 11 of the linkage 1 to slide along the first guide portion 01. Only then do the front leg assembly 100 and the rear leg assembly 200 unfold. If the rear leg assembly 200 cannot unfold directly, the front leg assembly 100, which is linked to it by the linkage 1, naturally cannot unfold directly either. This feature means that when the frame is folded up and placed upright, even if the front leg assembly 100 and the rear leg assembly 200 are subjected to external force, they cannot unfold on their own. They can only unfold smoothly by actively swinging the handlebars 300, thus achieving stable upright placement.

[0075] Example 2

[0076] This embodiment further defines the specific shape of the first guide part 01 and the way the first end 11 of the linkage member 1 cooperates with the first guide part 01 based on embodiment 1.

[0077] In this embodiment, the first guide portion 01 is a straight strip hole. This straight strip hole is provided on the rear foot assembly 200 (it can be a hole directly opened on the support arm of the rear foot assembly 200, or it can be indirectly provided through the connector 4 described in a later embodiment), and it extends in a straight direction to provide a straight guide trajectory for the first end 11 of the linkage 1.

[0078] The first end 11 of the linkage 1 is provided with a first mating part. The first mating part extends into the first guide part 01 and can slide along it;

[0079] As an optional implementation, the first mating part can be in the form of a pin or a cylindrical protrusion, with its outer diameter matching the inner diameter of the first guide part 01, ensuring that the first mating part can slide smoothly within the first guide part 01 while also having good mating stability.

[0080] Specifically, the first mating part and the first guide part 01 are in clearance fit to ensure smooth sliding. During the sliding process, the first mating part can rotate slightly relative to the first guide part 01 to adapt to the angle change requirements of the linkage 1 during the movement.

[0081] Through the sliding engagement between the aforementioned straight-line slot and the first mating part, the first end 11 of the linkage 1 obtains a defined linear motion trajectory on the rear foot assembly 200.

[0082] When the vehicle is retracted, the first end 11 of the linkage 1 slides along the first guide 01 in the first direction;

[0083] When unfolded, the first end 11 of the linkage 1 slides along the first guide 01 in a second direction opposite to the first direction. This linear guide engagement method has a simple structure, reliable movement, and is easy to manufacture and implement.

[0084] Example 3

[0085] This embodiment further defines the anti-detachment limiting structure of the first guide part 01 and the first mating part based on embodiment 2.

[0086] In this embodiment, the first guide portion 01 (e.g., a slot) has a first aperture section and a second aperture section along its through direction (i.e., the thickness direction of the slot), and the inner diameter of the first aperture section is smaller than the inner diameter of the second aperture section.

[0087] In other words, the first guide section 01 is not a through hole of equal diameter in the thickness direction, but forms a stepped hole structure: the hole diameter on one side is smaller (first hole diameter section), and the hole diameter on the other side is larger (second hole diameter section).

[0088] The first mating part is inserted into the first aperture section and the second aperture section. That is, the first mating part enters from the first aperture section, passes through the entire first guide part 01, and its end reaches the side where the second aperture section is located.

[0089] The outer diameter of the first mating part is smaller than the inner diameter of the first aperture section, so that the first mating part can slide freely in the first aperture section and the second aperture section without getting stuck.

[0090] The first mating part is provided with a first limiting head at the part located within the second aperture section. The outer diameter of the first limiting head is smaller than the inner diameter of the second aperture section but larger than the inner diameter of the first aperture section.

[0091] In other words, the size of the first limiting head is between the size of the first aperture segment and the second aperture segment. It can slide freely within the second aperture segment (larger aperture), but because its size is larger than the inner diameter of the first aperture segment (smaller aperture), it cannot disengage from the side where the first aperture segment is located.

[0092] The above structure achieves axial anti-disengagement limiting of the first mating part:

[0093] During assembly, the first mating part is inserted from one side of the first aperture section, passing through the first aperture section and the second aperture section, so that the first limiting head remains in the second aperture section. After assembly, the first limiting head is blocked by the first aperture section and cannot be removed. The first mating part can then slide freely in the first guide part 01 without accidentally falling off, ensuring the long-term reliability of the fit between the linkage 1 and the rear foot assembly 200.

[0094] It should be noted that the main body of the first mating part (i.e. the part other than the first limiting head) can have a uniform outer diameter along the axial direction or it can have a stepped structure, as long as it can freely pass through the first aperture section and form a limiting fit with the first limiting head.

[0095] Example 4

[0096] Based on Embodiment 1, this embodiment further defines the specific shape of the guide avoidance part 31 and the cooperation method between the second end 12 of the linkage 1 and the guide avoidance part 31.

[0097] In this embodiment, the guide avoidance part 31 is an arc-shaped strip hole, which is provided on the seat connector 3. Its arc-shaped trajectory is designed according to the motion path of the second end 12 of the linkage 1 during the retraction and unfolding process.

[0098] The second end 12 of the linkage 1 is provided with a second mating part, which extends into the guide clearance part 31 and can slide along it. The second mating part can take a similar form to the first mating part, that is, a pin or cylindrical protrusion structure, which extends into the arc-shaped slot and slides with it.

[0099] The main functions of the guide and avoidance unit 31 are twofold:

[0100] Firstly, during the retraction process, the seat connector 3 swings with the seat assembly 500, and the arc-shaped slot moves with the seat connector 3, providing clearance space for the second mating part, so that the second end 12 of the linkage 1 can not cause motion interference to the seat connector 3 when the seat connector 3 swings.

[0101] Secondly, when the frame is unfolded, the cooperation between the guide avoidance part 31 and the second mating part constitutes a support constraint on the seat connector 3, and together with the hinge point of the seat connector 3 and the frame, they form a double-point support, ensuring the stable support of the seat assembly 500 when the frame is unfolded.

[0102] In this embodiment, the guide clearance part 31 is preferably an arc-shaped slot, the center of which can coincide with the hinge point of the seat connector 3 and the frame, or it can be offset according to the actual spatial layout. When the center of the arc-shaped trajectory is offset from the hinge point, the cooperation between the guide clearance part 31 and the second mating part will produce a compound motion effect to prevent motion interference and jamming.

[0103] In addition, to improve the load-bearing stability of the seat connector 3 in the unfolded state, the guide avoidance part 31 can also be provided with a turning section 33 at its end. The turning section 33 extends in a turning shape relative to the arc-shaped extension direction of the guide avoidance part 31.

[0104] When the frame is in the unfolded state, the second mating part is located within the transition section 33. When the seat assembly 500 is subjected to force, the direction of the force applied to the seat connector 3 (approximately downward) is approximately perpendicular to or at a large angle to the extension direction of the transition section 33, so that the seat connector 3 will not swing due to the force, thereby ensuring the load-bearing stability of the seat assembly 500.

[0105] Example 5

[0106] This embodiment further defines the anti-detachment limiting structure between the guide avoidance part 31 and the second mating part based on embodiment 4.

[0107] In this embodiment, the guide clearance portion 31 has a third aperture section 34 and a fourth aperture section 35 along its through direction (i.e., the thickness direction of the arc-shaped strip hole), and the inner diameter of the third aperture section 34 is smaller than the inner diameter of the fourth aperture section 35.

[0108] That is, the guide avoidance part 31 forms a stepped hole structure in the thickness direction: one side has a smaller hole diameter (third hole diameter section 34), and the other side has a larger hole diameter (fourth hole diameter section 35).

[0109] The second mating part is inserted into the third aperture section 34 and the fourth aperture section 35. The outer diameter of the second mating part is smaller than the inner diameter of the third aperture section 34, so that the second mating part can slide freely in the third aperture section 34 and the fourth aperture section 35.

[0110] The second mating part is provided with a second limiting head 121 at the part located inside the fourth aperture section 35. The outer diameter of the second limiting head 121 is smaller than the inner diameter of the fourth aperture section 35 and larger than the inner diameter of the third aperture section 34.

[0111] The second limiting head 121 can slide freely within the fourth aperture section 35 (larger aperture), but because its size is larger than the inner diameter of the third aperture section 34 (smaller aperture), it is blocked by the third aperture section 34 and cannot be dislodged, thereby achieving axial anti-dislodgement limiting of the second mating part within the guide avoidance part 31.

[0112] This embodiment ensures the long-term reliability of the fit between the second end 12 of the linkage 1 and the seat connector 3 through the cooperation of the third aperture section 34, the fourth aperture section 35 and the second limiting head 121, preventing the second mating part from accidentally falling off the guide avoidance part 31 during use, and ensuring that the linkage relationship between the linkage 1 and the seat connector 3 is always effective.

[0113] Example 6

[0114] This embodiment further defines the mating relationship between the seat connector 3 and the front leg assembly 100.

[0115] In this embodiment, the seat connector 3 also has a fifth end 32. The fifth end 32 of the seat connector 3 is used to engage with the second guide portion 02 provided on the front foot assembly 100, and is capable of reciprocating along the second guide portion 02.

[0116] Specifically, in addition to having a guide and avoidance part 31 on its main body and being hinged to the frame, the fifth end 32 (which can be regarded as an extension end of the seat connector 3) of the seat connector 3 is movably engaged with the front foot assembly 100 through the second guide part 02. The second guide part 02 is provided on the front foot assembly 100 (such as the corresponding position of the front foot assembly 100 support arm) to provide a guide trajectory for the fifth end 32 of the seat connector 3.

[0117] The active cooperation between the fifth end 32 and the second guide part 02 enables relative movement between the fifth end 32 and the second guide part 02 when the seat connector 3 swings or when the front leg assembly 100 swings, thereby obtaining a definite motion constraint.

[0118] When the vehicle is retracted, the lower part of the seat assembly 500 causes the seat connector 3 to swing. The movement of the seat connector 3 is transmitted to the linkage 1 through the cooperation between the guide avoidance part 31 and the second mating part, and then acts on the front foot assembly 100 to assist the front foot assembly 100 to swing in the retracting direction, so that the fifth end 32 moves in the corresponding direction along the second guide part 02.

[0119] This embodiment further optimizes the motion constraint of the seat connector 3 by setting the fifth end 32 of the seat connector 3 to cooperate with the second guide part 02 on the front foot assembly 100, thereby improving the transmission efficiency and motion stability of the linkage retraction mechanism, and also making the seat connector 3 have more stable support in the unfolded state.

[0120] Example 7

[0121] This embodiment further defines the specific shapes of the guide avoidance part 31 and the second guide part 02 and their relative positional relationship based on embodiment 6.

[0122] In this embodiment, the guide clearance portion 31 is an arc-shaped slot provided on the seat connector 3, and the second guide portion 02 is an arc-shaped slot provided on the front foot assembly 100. When the frame is in the unfolded use state, the guide clearance portion 31 is located above the second guide portion 02, and the concave arc sides of the two are opposite to each other and the convex arc sides are opposite to each other.

[0123] Specifically, the guide and avoidance part 31 is provided on the main body part of the seat connector 3 (such as the flat part 36 of the seat connector 3), and the second guide part 02 is provided at the corresponding position of the front foot assembly 100 support arm.

[0124] With the chassis extended, viewed from the side, the guide and avoidance section 31 is spatially positioned above the second guide section 02;

[0125] The bending directions of the two arc-shaped slots are configured as follows:

[0126] The concave sides (i.e., the side with the arc-shaped depression) of both face each other, while the convex sides (i.e., the side with the arc-shaped protrusion) face away from each other. This arrangement of concave arcs facing each other and convex arcs facing away from each other ensures that the movement trajectory of the fifth end 32 of the seat connector 3 on the front foot assembly 100 and the movement trajectory of the second end 12 of the linkage 1 on the seat connector 3 are kinematically matched, ensuring that the components can move smoothly together without interference during the retraction process.

[0127] In the unfolded state of the frame, the above-mentioned positional relationship and arc-shaped configuration also ensure that the seat connector 3, through the cooperation of the fifth end 32 with the second guide part 02, the hinge of the seat connector 3 with the frame, and the cooperation of the guide avoidance part 31 with the second end 12 of the linkage part 1, together form a stable support system for the seat assembly 500, so that the seat assembly 500 will not shake or sway when bearing load.

[0128] Example 8

[0129] This embodiment further defines the specific cooperation method between the fifth end 32 and the second guide part 02 based on embodiment 7.

[0130] In this embodiment, the fifth end 32 of the seat connector 3 is provided with a third mating part. The third mating part extends into the second guide part 02 and can slide along it, and the third mating part and the second guide part 02 are in clearance fit, so that the fifth end 32 can slide along the second guide part 02 and rotate relative to it.

[0131] Specifically, the third mating part can be in the form of a pin, a cylindrical protrusion, or a slider, which extends into the second guide part 02 (arc-shaped slot);

[0132] The outer diameter of the third mating part is smaller than the inner diameter of the second guide part 02, and there is an appropriate gap between them, forming a clearance fit. This clearance fit allows the third mating part to slide freely along an arc-shaped trajectory within the second guide part 02, and also to rotate slightly relative to the second guide part 02 during the sliding process.

[0133] The reason for requiring both sliding and rotational degrees of freedom is that during the swinging process of the front foot assembly 100, the movement trajectory of the fifth end 32 is arc-shaped, and the second guide part 02 itself is also an arc-shaped slot. If the third mating part can only slide and not rotate, the seat connector 3 may experience interference and jamming due to angle changes during swinging. Achieving a combined sliding and rotational motion through clearance fitting completely avoids motion interference and ensures smooth linkage and retraction.

[0134] Example 9

[0135] This embodiment further defines the anti-detachment limiting structure of the second guide part 02 and the third mating part based on embodiment 8.

[0136] In this embodiment, the second guide portion 02 has a fifth aperture segment and a sixth aperture segment along its through direction (i.e., the thickness direction of the arc-shaped slot), and the inner diameter of the fifth aperture segment is smaller than the inner diameter of the sixth aperture segment. That is, the second guide portion 02 forms a stepped hole structure in the thickness direction: one side has a smaller aperture (the fifth aperture segment), and the other side has a larger aperture (the sixth aperture segment).

[0137] The third mating part is inserted into the fifth and sixth aperture sections. The outer diameter of the third mating part is smaller than the inner diameter of the fifth aperture section, so that the third mating part can slide freely in the fifth and sixth aperture sections.

[0138] The third fitting part is provided with a third limiting head at the part located within the sixth aperture section. The outer diameter of the third limiting head is smaller than the inner diameter of the sixth aperture section but larger than the inner diameter of the fifth aperture section.

[0139] The third limiting head slides freely within the sixth aperture section (larger aperture), but because its size is larger than the inner diameter of the fifth aperture section (smaller aperture), it is blocked by the fifth aperture section and cannot disengage, thus achieving axial anti-disengagement limiting of the third mating part within the second guide part 02.

[0140] This embodiment ensures the long-term reliability of the fit between the fifth end 32 of the seat connector 3 and the front foot assembly 100 through the cooperation of the fifth aperture section, the sixth aperture section and the third limiting head, prevents the third mating part from accidentally falling off the second guide part 02, and ensures that the linkage relationship between the seat connector 3 and the front foot assembly 100 is always effective.

[0141] Example 10

[0142] This embodiment further defines the arrangement of the first guide part 01 on the rear foot assembly 200 based on embodiment 1.

[0143] In this embodiment, the frame linkage assembly further includes a connector 4. The connector 4 is used to fix to the rear foot assembly 200, and the first guide portion 01 is disposed on the connector 4.

[0144] Specifically, the connector 4 is an independent part that is fixedly installed on the support arm of the rear leg assembly 200 (such as the upper part or middle part of the support arm of the rear leg assembly 200).

[0145] The fixing method between the connector 4 and the rear foot assembly 200 can be any feasible method such as welding, riveting, bolting, snap-fitting, or integral molding.

[0146] The first guide part 01 (straight strip hole) is provided on the connector 4. That is, the first guide part 01 is not directly opened on the body of the rear foot assembly 200, but is opened on the connector 4 and is indirectly provided on the rear foot assembly 200 through the connector 4.

[0147] The design using connector 4 has the following advantages:

[0148] Firstly, the rear foot assembly 200 support arm is usually made of tubular or irregular cross-section profile. Directly opening the guide part on the support arm is difficult to process and may affect the structural strength of the support arm. By adding the connecting part 4, the processing difficulty can be reduced and the structural strength can be guaranteed.

[0149] Secondly, the connecting part 4, as an independent part, can be manufactured using different materials or processes than the rear foot assembly 200 (such as using more wear-resistant materials or more precise machining methods) to improve the wear resistance and dimensional accuracy of the first guide part 01.

[0150] Thirdly, when the first guide part 01 is worn or damaged, only the connecting part 4 needs to be replaced, without replacing the entire rear foot assembly 200, resulting in low maintenance costs.

[0151] The specific shape of the connector 4 can be strip-shaped, plate-shaped, block-shaped, or bracket-shaped, as long as it can be fixed on the rear foot assembly 200 and provide the setting position of the first guide part 01. This embodiment does not make specific limitations.

[0152] Example 11

[0153] This embodiment further defines the articulation method between the fourth end 22 of the traction member 2 and the handlebar 300 based on embodiment 1.

[0154] In this embodiment, the fourth end 22 of the traction member 2 is used to hinge with the follower 5 provided on the handlebar 300;

[0155] That is, the fourth end 22 is not directly hinged to the handlebar 300 body, but is hinged through an intermediate component set on the handlebar 300.

[0156] The follower part 5 is fixedly mounted on the handlebar 300. It can be any form, such as a connecting piece welded to the handlebar 300, a lug detachably fixed to the handlebar 300, a hinge seat fixed to the handlebar 300 by bolts, or a ring-shaped component sleeved and fixed to the handlebar 300.

[0157] The follower part 5 is provided with a hinge hole or hinge shaft for hinge connection with the fourth end 22 of the traction member 2. During the retraction or unfolding of the frame, the follower part 5 swings together with the handlebars 300 and drives the traction member 2 to move through the hinge with the fourth end 22.

[0158] The significance of setting up the follower 5 is that:

[0159] The handlebar 300 body is typically a tubular component. Directly installing hinge structures (such as drilling or welding hinge seats) on it may damage the appearance of the handlebar 300 or affect its structural strength. By setting the follower 5, a reliable hinge point can be provided for the fourth end 22 of the traction member 2 without damaging the structure of the handlebar 300 body. At the same time, the position of the follower 5 can be flexibly adjusted according to the needs of the linkage stroke, which facilitates the optimization of the movement trajectory and force angle of the traction member 2.

[0160] Example 12

[0161] This embodiment further defines the specific shapes of the linkage 1 and the traction 2 based on embodiment 1.

[0162] In this embodiment, the linkage 1 is an arc-shaped component, and the traction component 2 is a straight long strip component.

[0163] The linkage component 1 is generally in the shape of an arc strip, and its arc shape is designed according to the motion trajectory of the linkage component 1 during the retraction and unfolding process.

[0164] Since the first end 11 of the linkage 1 moves linearly in the first guide part 01 (straight strip hole) of the rear foot assembly 200, while the second end 12 is simultaneously hinged to the front foot assembly 100 and movably cooperates with the guide clearance part 31 (arc strip hole) of the seat connector 3, the two ends of the linkage 1 move along the straight trajectory and the arc trajectory respectively during the movement. Designing the linkage 1 as an arc strip can better adapt to the transition between the different movement trajectories at both ends, reduce stress concentration and interference risk during the movement process, and make the linkage action smoother.

[0165] The traction component 2 is a straight, long strip component, that is, the traction component 2 is a straight, slender rod or strip, and its length dimension is much larger than its cross-sectional dimension;

[0166] During the retraction and unfolding process, the two ends of the traction component 2 are respectively hinged to the first end 11 of the linkage component 1 and the handlebar 300. Its straight shape makes the force transmission path the shortest and the transmission efficiency the highest. Moreover, the straight long strip component is easy to process and has low cost.

[0167] The specific materials of the linkage 1 and the traction component 2 can be metal (such as steel, aluminum alloy, etc.) or high-strength plastic, depending on the actual load requirements. This embodiment does not make specific limitations.

[0168] Example 13

[0169] This embodiment further defines the specific structure of the seat connector 3 based on embodiment 1.

[0170] In this embodiment, the seat connector 3 is a connecting part between the seat assembly 500 and the frame. The seat connector 3 includes a flat portion 36 and a connecting portion 37. The connecting portion 37 is used to connect with the seat assembly 500 of the trolley, and the guide clearance portion 31 is provided on the flat portion 36.

[0171] Specifically, the seat connector 3 has two functional areas as a whole;

[0172] The flat portion 36 is the main plate area of ​​the seat connector 3, which is roughly plate-shaped and has a large planar area. The guide clearance portion 31 (arc-shaped slot) is provided on the flat portion 36, that is, it is opened in this plate area;

[0173] The guide clearance part 31 is provided on the flat part 36 because the flat plate structure makes it easier to open the arc-shaped slot and helps to ensure the dimensional accuracy and shape accuracy of the slot.

[0174] At the same time, the flat plate section is subjected to uniform stress when bearing load and has strong resistance to deformation.

[0175] The connecting part 37 is a part on the seat connector 3 for connecting with the seat assembly 500, and can be one or more connecting seats, mounting holes, snap-fit ​​structures, plug-in interfaces or extension arms, etc.

[0176] The connection between the connecting part 37 and the seat assembly 500 can be any detachable connection method such as bolt connection, snap-fit, plug-in connection or quick-release connection, or it can be a fixed connection or integral molding.

[0177] The seat assembly 500 can be a seat (for children to sit in), a bassinet (for infants to lie in), a storage basket, or other functional components that need to be mounted on the frame.

[0178] The seat assembly 500 is mounted on the seat connector 3 via the connecting part 37 and swings together with the seat connector 3.

[0179] In this invention, the seat assembly 500 can be folded up together with the frame (i.e., fixedly connected to the seat connector 3, and swings down together with the seat connector 3 when the vehicle is folded up), or it can be an independent unit that can be separated from the frame.

[0180] When the seat assembly 500 is an independent unit, when the user needs to fold up the vehicle, he / she can directly apply force to the handlebars 300 and the seat connector 3, pressing down the handlebars 300 and the seat connector 3 to achieve linkage folding up the vehicle. The folding up action can be completed without the seat assembly 500 being installed on the seat connector 3.

[0181] When the seat assembly 500 is a standalone unit, it can be removed from the frame and stored separately, making it more flexible to use.

[0182] Example 14

[0183] This embodiment specifically describes a trolley with a linked trolley assembly, which has the aforementioned frame linkage component.

[0184] This embodiment provides a trolley with a linked trolley frame.

[0185] The frame has a front leg assembly 100, a rear leg assembly 200, and a handlebar 300.

[0186] The upper ends of the front foot assembly 100, the upper ends of the rear foot assembly 200, and the lower ends of the handlebars 300 are rotatably connected by the same joint mechanism 400.

[0187] The joint mechanism 400 has a locked state and an unlocked state:

[0188] When locked, the front leg assembly 100, the rear leg assembly 200 and the handlebars 300 are fixed relative to each other, and the frame remains in the unfolded state for use.

[0189] When unlocked, the three parts can rotate relative to each other to allow for folding or unfolding operations.

[0190] The frame is provided with a mounting and mating structure for cooperating with the frame linkage assembly. The frame linkage assembly is any of the frame linkage assemblies in embodiments 1 to 13 described above.

[0191] The frame linkage assembly is mounted on the frame and mates with the mounting and mating structure.

[0192] Specifically, "installation and mating structure" is a higher-level concept used to summarize the corresponding structure on the frame that mates with various components of the frame linkage assembly;

[0193] Depending on the specific implementation method of the linkage components, the installation and mating structure shall include at least one or more of the following:

[0194] Firstly, a first guide portion 01 (such as a straight strip hole) is provided on the rear leg assembly 200 for movable engagement with the first end 11 of the linkage member 1. The first guide portion 01 can be a strip hole directly formed on the support arm of the rear leg assembly 200, or it can be a strip hole provided on the connecting member 4 fixed on the rear leg assembly 200 (as described in Embodiment 10).

[0195] Secondly, a second guide portion 02 (such as an arc-shaped slot) is provided on the front foot assembly 100 for movable engagement with the fifth end 32 of the seat connector 3.

[0196] Thirdly, the follower part 5, which is provided on the handlebar 300, is used to hinge with the fourth end 22 of the traction member 2.

[0197] Fourth, a hinge structure (such as a hinge shaft or hinge hole) is provided on the frame for hinge connection with the seat connector 3.

[0198] Fifth, a fixing structure (such as a mounting base, welding position or bolt hole) is provided on the rear foot assembly 200 to fix the connecting piece 4.

[0199] The frame linkage assembly is assembled with the frame through the above-mentioned installation and mating structure, with each mating part corresponding to the other to form a complete linkage vehicle retraction system.

[0200] For a detailed explanation of the retraction and deployment operations, please refer to Example 1.

[0201] The trolley in this embodiment uses the aforementioned frame linkage component, which not only achieves reliable linkage folding but also significantly reduces the number of parts and manufacturing costs. Furthermore, it can stand stably upright after folding, greatly improving the convenience of storage and carrying.

[0202] Example 15

[0203] In a preferred embodiment of the invention, the frame of the handcart typically adopts a symmetrical structure.

[0204] The front foot assembly 100 includes two front foot support arms arranged symmetrically on the left and right. Each front foot support arm has a front wheel installed at its lower end. A braking system 6 can be installed on the front wheel as needed. The upper end of each front foot support arm is connected to the corresponding joint mechanism 400.

[0205] The rear foot assembly 200 includes two rear foot support arms arranged symmetrically on the left and right. The lower end of each rear foot support arm is equipped with a rear wheel. A braking system 6 can also be installed on the rear wheel as needed. The upper end of each rear foot support arm is connected to the corresponding joint mechanism 400.

[0206] The handlebar 300 includes two side bars arranged symmetrically on the left and right sides and a grip connected between the upper ends of the two side bars. The lower end of each side bar is connected to the corresponding joint mechanism 400.

[0207] There are usually two joint mechanisms 400 arranged symmetrically on the left and right sides of the frame. Each joint mechanism 400 is connected to the upper end of the front support arm, the upper end of the rear support arm, and the lower end of the handlebar 300 side bar on the same side.

[0208] The joint mechanism 400 has a locking mechanism inside, which is used to fix the three parts relative to each other when in the unfolded state.

[0209] Correspondingly, there are usually two sets of frame linkage components, which are installed on the left and right sides of the frame respectively. That is, the frame linkage component on each side cooperates with the joint mechanism 400 and other components on the same side. The two sets of linkage components are structurally symmetrical to achieve a balanced linkage retraction effect.

[0210] For ease of description, this manual describes the frame linkage components and their mating relationships on one side only. The structure and working principle of the other side are the same and will not be described again.

[0211] Example 16

[0212] This embodiment further describes the additional structure of the seat assembly 500 based on any one of the solutions described in embodiments 1 to 15.

[0213] The seat assembly 500 is equipped with a sunshade frame 7, which is a swingable frame structure used to support the sunshade fabric to block sunlight. The sunshade frame 7 can be hinged to the exterior of the joint mechanism 400, that is, one end of the sunshade frame 7 is rotatably connected to the housing or outer wall of the joint mechanism 400 through a hinge shaft, so that the sunshade frame 7 can swing around the joint mechanism 400, thereby lifting the sunshade upward when it is in the unfolded state and retracting it downward to reduce its volume when it is in the retracted state.

[0214] The seat assembly 500 also includes a connecting arm 8, which is a rod-shaped member with a certain extension length and has an upper end and a lower end. The upper end of the connecting arm 8 is hinged to the sunshade frame 7, that is, the upper end of the connecting arm 8 is rotatably connected to the sunshade frame 7 through a hinge shaft; the lower end of the connecting arm 8 is hinged to the connecting part 37 of the seat connector 3, that is, the lower end of the connecting arm 8 is rotatably connected to the connecting part 37 of the seat connector 3 through a hinge shaft. The length of the connecting arm 8 and the hinge position are set according to matching the swing amplitude of the sunshade frame 7 and the swing stroke of the seat connector 3.

[0215] When retracting the vehicle, the user releases the locking mechanism 400 and presses down on the seat assembly 500. The seat assembly 500 causes the seat connector 3 to swing, and the connecting part 37 of the seat connector 3 pulls the sunshade frame 7 through the connecting arm 8, causing the sunshade frame 7 to swing and retract synchronously in the retraction direction along with the swing of the seat connector 3. When the frame is fully retracted, the sunshade frame 7 also retracts to a position close to the seat assembly 500 or close to the main body of the frame, without requiring the user to operate the sunshade frame 7 separately.

[0216] When unfolding, the user moves the handlebars 300 to unfold the frame, and the seat assembly 500 returns to its original position. The connecting part 37 of the seat connector 3 pushes the sunshade frame 7 via the connecting arm 8, causing the sunshade frame 7 to swing and lift synchronously in the unfolding direction as the seat connector 3 swings. When the frame is fully unfolded, the sunshade frame 7 also unfolds to the working position. The connecting arm 8 connects the sunshade frame 7 to the connecting part 37 of the seat connector 3, so that the folding and unfolding of the sunshade frame 7 is linked to the folding and unfolding of the frame, eliminating the need for separate operation and further improving ease of use. At the same time, the sunshade frame 7 is hinged to the exterior of the joint mechanism 400, utilizing the existing position of the joint mechanism 400 on the frame as the hinge mounting point, eliminating the need for additional mounting structures in other parts of the frame, which helps maintain the overall simplicity of the frame.

[0217] Example 17

[0218] This embodiment further explains the elastic structure for assisting in vehicle retrieval, based on any one of the solutions described in Embodiments 1 to 16.

[0219] The frame linkage assembly also includes an elastic element, which is located at the follower 5 and acts on the follower 5, thereby indirectly applying an elastic tendency to the handlebars 300 to move in the retraction direction to assist the retraction operation.

[0220] Specifically, the follower 5 moves with the handlebar 300, and the fourth end 22 of the traction member 2 is hinged to the follower 5. The elastic element is a torsion spring, which is sleeved on the connecting shaft between the follower 5 and the handlebar 300 or on the hinge shaft between the follower 5 and the fourth end 22 of the traction member 2.

[0221] The torsion spring has a first torsion arm and a second torsion arm. The first torsion arm is fixed or abuts against the follower 5, and the second torsion arm is fixed or abuts against the frame (for example, abutting against or fixedly connected to the housing of the joint mechanism 400). When the frame is in the extended state, the torsion spring stores energy through torsion, and its elastic restoring force acts on the handlebars 300 through the follower 5, so that the handlebars 300 always have a tendency to swing in the retracted direction.

[0222] When the user releases the locking of the joint mechanism 400, the elastic potential energy stored in the torsion spring is released, which pushes the handlebar 300 to automatically swing in the retraction direction through the follower 5, thereby assisting the user in completing the retraction action. The user only needs to apply force to the seat assembly 500 and guide the retraction direction of the handlebar 300, without having to apply a large downward force to the handlebar 300, making the retraction operation more effortless and convenient.

[0223] When the frame is in the retracted position, the torsion spring maintains an elastic force on the handlebars 300 in the retracted direction, so that the handlebars 300 remain stably retracted in the retracted position and will not be accidentally unfolded due to shaking or external force.

[0224] It should be understood that torsion springs can also be provided at other hinge points between the handlebars 300 and the frame, as long as they can apply an elastic tendency to move the handlebars 300 in the retraction direction. The elastic element is not limited to torsion springs; in other embodiments, tension springs, compression springs, coil springs, and other forms of elastic elements can also be used, as long as they can achieve the same elastic auxiliary function, and all of these fall within the scope of protection of this invention.

[0225] Example 18

[0226] This embodiment further explains the foldable handlebar structure and its specific implementation method of unlocking the joint structure by driving a traction rope, based on any one of the solutions described in embodiments 1 to 17.

[0227] In this embodiment, the handlebar 300 is a foldable handlebar. Specifically, the handlebar 300 includes an upper section 301 and a lower section 302, which are rotatably connected by a folding hinge shaft, allowing the upper section 301 to be folded and flipped relative to the lower section 302. A folding locking mechanism 303 is also provided between the upper section 301 and the lower section 302 to fix the upper section 301 and the lower section 302 relative to each other when the frame is unfolded, preventing the handlebar 300 from folding accidentally during use. The folding locking mechanism 303 can adopt conventional forms in the art such as buckle locking, locking pin locking, rotating lock sleeve locking, or rotating joint. The user can release the folding locking mechanism by pressing the unlock button or rotating the unlock ring, giving the upper section the freedom to fold and rotate relative to the lower section.

[0228] The tow rope 600 is a flexible towing component, with one end connected to the foldable portion of the handlebar 300 (i.e., the upper section 301) and the other end connected to the rotating component 404 within the joint structure 400. When the user releases the folding locking mechanism 303 of the handlebar 300, a folding force is applied to the upper section 301. The upper section 301 rotates relative to the lower section 302 around the folding hinge axis. During the folding process, the distance and relative angle between the upper section 301 and the lower section 302 change, thereby pulling the tow rope 600. As the tow rope 600 is pulled, its other end pulls the rotating component 404 within the joint structure 400 to rotate around its own axis or hinge axis.

[0229] The joint structure 400 includes a joint housing. A socket 401, which can be a blind hole or a through hole, is fixedly provided within the joint structure 400. An active button 402 is movably mounted on the joint structure 400, and the active button 402 can reciprocate in a linear direction relative to the joint structure 400. A plug 403 is fixedly provided on the active button 402, and the plug 403 moves synchronously with the active button 402. Under normal conditions, the active button 402 is subjected to a biasing force from a tension spring (not shown), keeping the plug 403 inserted into the socket 401. At this time, the joint structure 400 is in a locked state, and the front foot assembly 100, rear foot assembly 200, and handlebar 300 cannot rotate relative to each other. A return spring (not shown) is also provided, acting on the rotating component 404, to apply an elastic force for automatic reset of the rotating component 404.

[0230] The rotating component 404 is rotatably mounted within the joint housing of the joint structure 400. One end of the traction rope 600 is connected to the eccentric position or the traction arm on the outer periphery of the rotating component 404, so that when the traction rope 600 is pulled, it can generate torque on the rotating component 404, driving the rotating component 404 to rotate. A bevel engagement structure is provided between the rotating component 404 and the active button 402. Specifically, the rotating component 404 has a first bevel 405, and the active button or an intermediate component that engages with the active button has a second bevel 406. The first bevel 405 and the second bevel 406 abut against each other. When the rotating component 404 rotates under the pull of the traction rope 600, the first inclined plane 405 slides relative to the second inclined plane 406. Due to the lifting effect of the inclined plane, the rotation of the rotating component 404 is converted into the movement of the movable button 402 or the intermediate component in a straight line, pushing the movable button 402 to overcome the tension of the tension spring and move away from the socket 401, thereby causing the plug 403 to exit the socket 401, and the joint structure 400 to switch from the locked state to the unlocked state.

[0231] Once the joint structure 400 is unlocked, the front leg assembly 100, rear leg assembly 200, and handlebars 300 gain relative rotational freedom. Since the user's folding action of the handlebars 300 is a continuous downward pressing process, after the folding action is complete, the user does not need to release their hand; they can continue pressing down on the handlebars 300, causing them to swing around the joint structure 400 towards the rear leg assembly 200. Simultaneously, the user's other hand presses down on the seat assembly 500, causing it to swing towards the front leg assembly 100. Through the transmission action of the frame linkage assembly, the lowering of the handlebars 300, via the traction member 2 and the linkage member 1, causes the rear leg assembly 200 to fold, and the lowering of the seat assembly 500, via the seat connector 3 and the linkage member 1, causes the front leg assembly 100 to fold, thus completing the frame's coordinated folding action in one step. Throughout the entire operation, the user only needs to perform one continuous action sequence: "unlock the folding locking mechanism → fold the handlebars → press down smoothly." The three steps of folding the handlebars, unlocking the joints, and retracting the bike are automatically connected in sequence, eliminating the need for separate operations and greatly improving the convenience and efficiency of retracting the bike.

[0232] When the frame is unfolded, the user moves the handlebars upwards to unfold the frame into place. The upper section 301 of the handlebars can rotate in the opposite direction to the lower section 302 and unfold. It is then locked by the folding locking mechanism 303, restoring the handlebars to the unfolded length. At the same time, the return spring acts on the rotating part 404, causing the rotating part 404 to automatically reset. This also causes the traction rope 600 to automatically reset. The bias force of the tension spring resets the active button 402, and the plug 403 is reinserted into the socket 401. The joint structure 400 returns to the locked state, and the frame remains in the unfolded state.

[0233] Preferably, the traction rope 600 is a steel wire rope covered with a protective sleeve. The two ends of the protective sleeve are respectively fixed to the corresponding parts of the handlebar 300 and the shell of the joint structure. The traction rope 600 is inserted into the protective sleeve to avoid friction or entanglement between the traction rope and other components during movement, thus ensuring the reliability and service life of the transmission.

[0234] It should be noted that the structures, components, and their cooperation principles not described in detail in this application, including but not limited to the internal shell structure of the joint structure, the conventional implementation of the locking mechanism (such as the cooperation method of the locking pin and the locking hole), the guide installation structure of the active button, the support and reset structure of the rotating part, the way the traction rope is threaded and the arrangement of the sheath, the folding hinge structure of the folding handlebar and the specific form of its locking mechanism, the braking system structure of the front and rear wheels, the hinge shafts and connection methods of each component, etc., are all conventional designs that can be known by those skilled in the art based on ordinary technical knowledge or implemented with reference to existing technology, and these existing technical parts are not the inventive point of this invention. After reading this specification and the drawings, those skilled in the art, combined with common knowledge in the field, can fully understand and implement the technical solution of this invention without creative effort. Therefore, the above-mentioned undetailed content should not be regarded as a reason for insufficient disclosure in this application. All equivalent structural transformations made using the content of this specification and drawings under the concept of this invention, or direct / indirect applications in other related technical fields, are within the protection scope of this patent.

[0235] The handcart provided by this invention, through the coordinated arrangement of linkage components, traction components and seat connectors, only requires three main components to simultaneously realize the linkage folding of the handle, rear leg assembly, front leg assembly and seat assembly. It eliminates the need for multiple independent linkage mechanisms and limiting linkages, greatly reducing the number of parts and hinge points, lowering manufacturing costs and assembly difficulty, and reducing cumulative fit clearance, making the linkage action smoother and more reliable.

[0236] More importantly, this invention features a foldable handlebar and a traction rope between the handlebar and the joint structure. This allows the user's folding action to simultaneously pull the rotating components within the joint structure. The inclined surface mechanism then lifts the movable button, disengaging the insert and automatically unlocking the joint. Simultaneously, the overall frame lock is released, allowing the user to continue pressing down and directly initiate the folding process. The handlebar folding, joint unlocking, and folding actions are integrated into one process, eliminating the need for separate steps and significantly improving folding convenience and efficiency. Furthermore, the folded handlebar eliminates the problem of protruding handlebars in traditional handcarts, resulting in a more compact and neat folded shape. When standing upright, the center of gravity is lower, it occupies less space, and there is no risk of snagging or collision due to protruding handlebars, significantly improving storage and portability.

[0237] Furthermore, the design of the fourth end of the traction component and the handlebar hinge point being located at a critical position ensures that the frame can stand stably after folding without accidentally opening. The linkage component, in the unfolded state, also functions as a limiter to prevent the front and rear leg assemblies from over-expanding, eliminating the need for additional limit linkages. The seat connector, through its hinge with the frame and the cooperation between the second end of the linkage component and the guide clearance part, forms a dual-point support in the unfolded state, ensuring the load-bearing stability of the seat assembly. Overall, this invention achieves a high degree of integration of multiple functions with minimal components, including simultaneous handlebar folding and unlocking, linked folding, unfolding limit, prevention of accidental unfolding during folding, and stable seat support. It has a compact structure, is easy to operate, and possesses good practical value and market potential.

[0238] The above embodiments have provided a detailed description of the present invention from multiple perspectives. Those skilled in the art should understand that the technical features in the above embodiments can be arbitrarily combined and used to form more implementation methods without conflict. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A trolley with a linkage mechanism, comprising a frame having a front leg assembly (100), a rear leg assembly (200), and a handlebar (300), wherein the front leg assembly (100), the rear leg assembly (200), and the handlebar (300) are rotatably connected via a common joint mechanism (400), the joint mechanism (400) having a locked state and an unlocked state, wherein the three parts are relatively fixed in the locked state and can rotate relative to each other in the unlocked state, characterized in that... The handlebar (300) is a foldable handlebar; The trolley also includes a traction rope (600), which is connected between the handle (300) and the joint structure (400). When the handle (300) is folded, the traction rope (600) drives the joint structure (400) to switch from the locked state to the unlocked state. The handcart also includes a frame linkage assembly, which is installed on the frame and is used to achieve linkage folding by pressing down the handle (300) and the seat assembly (500) after the joint structure is unlocked; The frame linkage assembly includes: The linkage (1) has a first end (11) and a second end (12). The first end (11) is movably engaged with a first guide (01) provided on the rear leg assembly (200) and can reciprocate along the first guide (01). The second end (12) is hinged to the front leg assembly (100). The traction member (2) has a third end (21) and a fourth end (22), the third end (21) being hinged to the first end (11) of the linkage member (1), and the fourth end (22) being hinged to the handlebar (300); The seat connector (3) is hinged to the frame and is used to connect with the seat assembly (500). The seat connector (3) is provided with a guide avoidance part (31). The second end (12) of the linkage (1) is also in movable cooperation with the guide avoidance part (31).

2. The handcart with linked retrieval as described in claim 1, characterized in that: The first guide portion (01) is a straight strip hole, and the first end (11) of the linkage member (1) is provided with a first mating portion, which extends into the first guide portion (01) and can slide along it.

3. The handcart with linked retrieval as described in claim 2, characterized in that: The first guide portion (01) has a first aperture section and a second aperture section along its through direction. The inner diameter of the first aperture section is smaller than the inner diameter of the second aperture section. The first mating portion passes through the first aperture section and the second aperture section. The outer diameter of the first mating portion is smaller than the inner diameter of the first aperture section. The portion of the first mating portion located in the second aperture section is provided with a first limiting head. The outer diameter of the first limiting head is smaller than the inner diameter of the second aperture section and larger than the inner diameter of the first aperture section.

4. The handcart with linked retrieval as described in claim 1, characterized in that: The guide clearance part (31) is an arc-shaped strip hole, and the second end (12) of the linkage (1) is provided with a second mating part, which extends into the guide clearance part (31) and can slide along it.

5. The handcart with linked retrieval as described in claim 4, characterized in that: The guide clearance part (31) has a third aperture section (34) and a fourth aperture section (35) along its through direction. The inner diameter of the third aperture section (34) is smaller than the inner diameter of the fourth aperture section (35). The second mating part passes through the third aperture section (34) and the fourth aperture section (35), and the outer diameter of the second mating part is smaller than the inner diameter of the third aperture section (34). The part of the second mating part located in the fourth aperture section (35) is provided with a second limiting head (121). The outer diameter of the second limiting head (121) is smaller than the inner diameter of the fourth aperture section (35) and larger than the inner diameter of the third aperture section (34).

6. The handcart with linked retrieval as described in claim 1, characterized in that: The seat connector (3) has a fifth end (32) for engaging with a second guide (02) provided on the front foot assembly (100) and for reciprocating along the second guide (02).

7. The handcart with linked retrieval as described in claim 6, characterized in that: The guide clearance part (31) is an arc-shaped strip hole provided on the seat connector (3), and the second guide part (02) is an arc-shaped strip hole provided on the front foot assembly (100). When the frame is in the unfolded use state, the guide clearance part (31) is located above the second guide part (02), and the concave arc sides of the two are opposite to each other and the convex arc sides are opposite to each other.

8. The handcart with linked retrieval as described in claim 7, characterized in that: The fifth end (32) is provided with a third mating part, which extends into the second guide part (02) and can slide along it. The third mating part and the second guide part (02) are in clearance fit so that the fifth end (32) can slide along the second guide part (02) and rotate relative to it.

9. The handcart with linked retrieval as described in claim 8, characterized in that: The second guide portion (02) has a fifth aperture section and a sixth aperture section along its through direction. The inner diameter of the fifth aperture section is smaller than the inner diameter of the sixth aperture section. The third mating portion passes through the fifth aperture section and the sixth aperture section. The outer diameter of the third mating portion is smaller than the inner diameter of the fifth aperture section. The third mating portion is provided with a third limiting head at the part located in the sixth aperture section. The outer diameter of the third limiting head is smaller than the inner diameter of the sixth aperture section and larger than the inner diameter of the fifth aperture section.

10. The handcart with linked retrieval as described in claim 1, characterized in that: The fourth end (22) is used to hinge with the follower (5) provided on the handlebar (300).

11. The handcart with automatic folding mechanism as described in any one of claims 1 to 10, characterized in that: The joint structure has a socket and a movable button. The movable button has a plug. The movable button can move relative to the joint structure, so that the plug can be inserted into or out of the socket to form the locked state and the unlocked state. Under normal conditions, the movable button is subjected to the biasing force of the tension spring to keep the plug inserted in the socket. The joint structure also includes a rotating component. The traction rope is connected between the handlebar and the rotating component. When the handlebar is folded, the rotating component is pulled to rotate by the traction rope. The rotating component and the movable button are provided with a beveled engagement structure. When the rotating component rotates, the movable button is pushed by the beveled engagement structure to overcome the bias force of the tension spring, so that the plug-in is disengaged from the socket. A reset spring is also provided, which applies an elastic force to the rotating component to automatically reset it.

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