Multi-state transportation device and deformation method thereof

Abstract

The invention relates to a multi-state transportation device and a deformation method thereof.The multi-state transportation device comprises a main frame and at least one expansion unit arranged on the side portion of the main frame, the main frame and the expansion unit are connected through a composite guide mechanism, and the expansion unit is folded in the main frame in the initial state and forms a small storage space; when the main frame is lifted upwards, the expansion unit moves downwards through the composite guide mechanism and can be unfolded outwards, so that a large storage space is formed. The device is simple in structure and reasonable in design, the functions of a storage box and a hand buggy are perfectly integrated, one object has two purposes, the problem that double space is occupied in a traditional scheme is thoroughly solved, the folding operation from an unfolding state to a storage state becomes extremely simple, convenient and labor-saving through a gravity-assisted composite guide mechanism, the user experience is excellent, and the practicability is high. Complex electric components are avoided, durability is good, and maintenance is easy.

Description

Technical Field

[0001] This invention relates to a multi-state transportation device and its transformation method. Background Technology

[0002] With the increasing popularity of private cars and the rise in activities such as self-driving tours, outdoor camping, and large-scale shopping, car owners have higher demands for efficient use of trunk space and convenient cargo handling. Currently, a common practice is for car owners to place a storage box in the trunk to organize miscellaneous items, while also keeping a handcart for carrying heavy objects. This method has two obvious drawbacks: (1) storing two items at the same time takes up a lot of trunk space; (2) it has a single function and cannot be interchanged.

[0003] Based on the aforementioned drawbacks, some foldable handcarts exist in the existing technology, but they typically have irregular shapes after folding, limited volume reduction, and complex folding structures, making operation cumbersome. Furthermore, when used as storage boxes, their internal space is irregular and their sealing is poor, resulting in a less than ideal user experience. Therefore, there is an urgent need for a highly integrated, easily convertible, and structurally reliable solution. Summary of the Invention

[0004] The present invention improves upon the above-mentioned problems. Specifically, the technical problem to be solved by the present invention is to provide a multi-state transportation device and its transformation method, which has a simple structure and is easy to use.

[0005] The present invention is constructed as follows: it includes a main frame and at least one extension unit disposed on the side of the main frame. The main frame and the extension unit are connected by a composite guide mechanism. In the initial state, the extension unit is folded inside the main frame to form a small storage space. When the main frame is lifted upward, the extension unit moves downward through the composite guide mechanism under the action of gravity and can be unfolded outward to form a large storage space.

[0006] Furthermore, the composite guide mechanism includes a composite guide groove disposed on the extension unit and a first pivot and a second pivot disposed on the main frame. The composite guide groove includes a first guide groove and a second guide groove. The first pivot and the second pivot can slide along the first guide groove and the second guide groove, respectively, and the first and second pivots are rotatably engaged with the first and second guide grooves, respectively.

[0007] Furthermore, the first guide groove is a straight groove, and the second guide groove includes a straight section and an arc-shaped limiting section.

[0008] Furthermore, the front and rear of the main frame are provided with cavities for accommodating the expansion unit; a caster assembly is provided at the bottom of the outer side of the expansion unit, and a caster storage groove is provided in the cavity corresponding to the position of the caster assembly.

[0009] Furthermore, it also includes a detachable enclosure assembly between the main frame and the extension unit. The enclosure assembly includes a front plate, a rear plate, a side plate, and a bottom plate. One end of the bottom plate is hinged to the main frame, and the other end of the bottom plate is hinged to the side plate. Both the front and rear plates are hinged to the bottom plate.

[0010] Furthermore, when in the stowed state, the side panel is connected to the expansion unit via locking component A; when in the unfolded state, the front and rear panels are connected to the main frame via locking component B, and the side panel is connected to the expansion unit via locking component C.

[0011] Furthermore, it also includes a fencing assembly, which includes a front panel, a rear panel, side panels, and a bottom panel. The side panels are hinged to the extension unit, and the front and rear panels are made of flexible fabric.

[0012] Furthermore, when in the stowed state, the main frame and the side panel are connected via locking assembly D; when in the unfolded state, the side panel and the main frame are connected via locking assembly E, and the bottom plate and the main frame are connected via locking assembly F.

[0013] Furthermore, a telescopic handle is installed on the outside of the expansion unit.

[0014] Furthermore, a method for modifying a multi-state transport device includes the following: When it is necessary to expand the transport device, the main frame is lifted so that the expansion unit unfolds after undergoing a compound movement relative to the main frame via a compound guide mechanism. When the main frame is raised, the expansion unit first translates downward relative to the first guide groove of the compound guide mechanism under the action of gravity, and the second pivot of the compound guide mechanism translates downward relative to the straight section of the second guide groove of the compound guide mechanism. Then, the expansion unit is flipped outward and unfolded with the assistance of external force. At this time, the second pivot moves and is limited along the arc-shaped limiting section, so that the caster assembly forms support with the ground. Then, the enclosure assembly is installed to form a larger mobile storage space.

[0015] Furthermore, a method for modifying a multi-state transport device includes the following: when it is necessary to shrink and expand the transport device, the enclosure assembly is unlocked, the main frame is lifted and then lowered again. During this process, the expansion unit will rotate and reset under the action of gravity or external force. The second pivot of the composite guide mechanism moves from the outer end of the arc-shaped limiting section of the second guide groove of the composite guide mechanism to the inner end. Then, during the process of lowering again, the second pivot moves along the straight section of the second guide groove, and the first pivot of the composite guide mechanism resets along the first guide groove of the composite guide mechanism, realizing convenient folding. After the enclosure assembly is installed, a smaller storage space is formed.

[0016] Compared with existing technologies, this invention has the following advantages: The invention has a simple structure and reasonable design, perfectly integrating the functions of a storage box and a trolley, serving two purposes in one. It completely solves the problem of traditional solutions occupying twice the space. Through a gravity-assisted composite guiding mechanism, the folding operation from the unfolded state to the folded state becomes extremely simple and labor-saving, providing an excellent user experience. Furthermore, being a purely mechanical structure, it avoids complex electric components, ensuring good durability and simple maintenance. It is suitable for various scenarios requiring "last mile" transportation, such as supermarket shopping, outdoor camping, airport pick-up and drop-off, and New Year's goods transport. Whether it's the sliding motion during unfolding or the rotational reset during folding, gravity is the core driving force, greatly simplifying user operation. When unfolding is needed, the user lifts the main frame, and under the action of gravity, the extension unit unfolds relative to the main frame through the composite guiding mechanism. When opened, the first pivot of the extension unit moves downward relative to the first guide groove under the action of gravity, and the second pivot moves downward relative to the straight section of the second guide groove. Then, with the assistance of external force, the extension unit flips outward and unfolds, that is, the second pivot moves along the arc-shaped limiting section, so that the caster assembly forms support with the ground. After installing the enclosure assembly, a large mobile storage space can be formed. After installing the telescopic handle, it becomes a mobile campervan. When it needs to be stored, the enclosure assembly is folded up. Similarly, it is only necessary to lift the main frame again and then put it down again. During this process, the extension unit will rotate and reset under the action of gravity or external force, that is, the second pivot moves from the outer end of the arc-shaped limiting section of the second guide groove to the inner end. Then, during the process of putting it down again, the second pivot moves along the straight section of the second guide groove, and the first pivot moves along the first guide groove to reset, realizing convenient folding. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the storage state in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the unfolded state of Embodiment 1 of the present invention. Figure 1 ; Figure 3 This is a schematic diagram of the unfolded state of Embodiment 1 of the present invention. Figure 2 ; Figure 4 This is a schematic diagram of the main frame and expansion unit in the unfolded state of Embodiment 1 of the present invention; Figure 5 for Figure 4 A magnified view of a section at point A in the middle; Figure 6 This is a schematic diagram of the extended unit and composite guiding mechanism in the storage state of Embodiment 1 of the present invention; Figure 7 This is a schematic diagram of the extended unit structure in the storage state of Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the cavity location structure of the expansion unit in Embodiment 1 of the present invention; Figure 9 This is a schematic diagram of the working state of Embodiment 1 of the present invention. Figure 1 ; Figure 10 This is a schematic diagram of the working state of Embodiment 1 of the present invention. Figure 2 ; Figure 11 This is a schematic diagram of the working state of Embodiment 1 of the present invention. Figure 3 ; Figure 12 This is a schematic diagram of the working state of Embodiment 1 of the present invention. Figure 4 ; Figure 13 This is a schematic diagram of the enclosure component structure according to Embodiment 1 of the present invention; Figure 14 This is a schematic diagram of the elastic bead structure in Embodiment 1 of the present invention; Figure 15 This is a schematic diagram illustrating the working process of Embodiment 1 of the present invention. Figure 1 ; Figure 16 This is a schematic diagram illustrating the working process of Embodiment 1 of the present invention. Figure 2 ; Figure 17 This is a schematic diagram illustrating the working process of Embodiment 1 of the present invention. Figure 3 ; Figure 18 This is a schematic diagram illustrating the working process of Embodiment 1 of the present invention. Figure 4 ; Figure 19 This is a reference diagram showing another usage state of Embodiment 1 of the present invention; Figure 20 This is a schematic diagram of the locking component B structure in Embodiment 1 of the present invention; Figure 21 This is a schematic diagram of the locking component C structure according to Embodiment 1 of the present invention; Figure 22 This is a schematic diagram of the locking component H structure in Embodiment 1 of the present invention; Figure 23 This is a schematic diagram of the unfolded structure of Embodiment 2 of the present invention. Figure 1 ; Figure 24 for Figure 23 Enlarged view of a section at point B in the middle; Figure 25 This is a schematic diagram of the unfolded structure of Embodiment 2 of the present invention. Figure 2 ; Figure 26 This is a schematic diagram of the storage state structure in Embodiment 2 of the present invention. Figure 1 ; Figure 27 for Figure 26 Enlarged view of a section at point C; Figure 28This is a schematic diagram of the overall structure after the side panel is opened in Embodiment 2 of the present invention; Figure 29 This is a schematic diagram of the unfolded structure of Embodiment 2 of the present invention. Figure 3 ; Figure 30 This is a schematic diagram of the storage state structure in Embodiment 2 of the present invention. Figure 2 ; Figure 31 This is a schematic diagram of the enclosure component structure in Embodiment 2 of the present invention; Figure 32 This is a schematic diagram of the side plate and expansion unit structure according to an embodiment of the present invention; Figure 33 This is a schematic diagram of the locking component D structure according to an embodiment of the present invention; Figure 34 This is a schematic diagram illustrating the working process of Embodiment 2 of the present invention. Figure 1 ; Figure 35 This is a schematic diagram illustrating the working process of Embodiment 2 of the present invention. Figure 2 ; Figure 36 This is a schematic diagram illustrating the working process of Embodiment 2 of the present invention. Figure 3 ; Figure 37 This is a schematic diagram illustrating the working process of Embodiment 2 of the present invention. Figure 4 ; Figure 38 This is a schematic diagram of the locking component F structure according to an embodiment of the present invention; Figure 39 This is a simplified diagram illustrating the working state of Embodiment 3 of the present invention. Figure 1 ; Figure 40 This is a simplified diagram illustrating the working state of Embodiment 3 of the present invention. Figure 2 ; Figure 41 This is the working state of Embodiment 4 of the present invention. Figure 1 ; Figure 42 This is the working state of Embodiment 4 of the present invention. Figure 2 ; Figure 43 This is the working state of Embodiment 4 of the present invention. Figure 3 ; Figure 44 This is the working state of Embodiment 4 of the present invention. Figure 4 ; Figure 45 This is an exploded view of Embodiment 4 of the present invention. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0019] Example 1: As Figures 1-21 As shown, in this embodiment, a multi-state transportation device is provided, including a main frame 100 and at least one extension unit 200 disposed on the side of the main frame. In the normal state, there are two extension units, located on both sides of the main frame respectively. The main frame and the extension units are connected by a composite guide mechanism 300. In the initial state, the extension units are folded inside the main frame to form a small storage space. When the main frame is lifted upward, the extension units move downward through the composite guide mechanism under the action of gravity and can be unfolded outward to form a large storage space.

[0020] When in operation: When it needs to be unfolded, the user lifts the main frame directly or indirectly (e.g., by lifting the side panel). Under the action of gravity, the extension unit unfolds after undergoing a compound movement relative to the main frame via the compound guide mechanism. First, under the action of gravity, the first pivot of the extension unit moves downward relative to the first guide groove, and the second pivot moves downward relative to the straight section of the second guide groove. Then, with the assistance of external force, the extension unit flips outward and unfolds (e.g., flips about 50 degrees). The second pivot moves along the arc-shaped limiting section, so that the caster assembly forms a support with the ground. After installing the enclosure assembly, a large mobile storage space can be formed. After installing the telescopic handle, it becomes a mobile campervan. When it needs to be stored away, simply fold up the enclosure components. Similarly, you only need to lift the main frame again and then put it down again. During this process, the extension unit will rotate and reset under the action of gravity or external force. That is, the second pivot moves from the outer end of the arc-shaped limiting section of the second guide groove to the inner end. Then, during the process of putting it down again, the second pivot moves along the straight section of the second guide groove, and the first pivot resets along the first guide groove, thus achieving convenient folding.

[0021] In this embodiment of the invention, the composite guide mechanism 300 includes a composite guide groove 310 disposed on the extension unit and a first pivot 320 and a second pivot 330 disposed on the main frame. The composite guide groove includes a first guide groove 311 and a second guide groove 312. The first guide groove is disposed above the second guide groove. The first pivot and the second pivot can slide along the first guide groove and the second guide groove, respectively, and the first and second pivots are rotatably engaged with the first and second guide grooves, respectively. That is, the first pivot can slide and rotate in the first guide groove, and the second pivot can slide and rotate in the second guide groove.

[0022] Of course, the composite guide groove can also be set on the main frame, and the first and second pivots can also be set on the extension unit.

[0023] In this embodiment of the invention, the first guide groove is a straight groove, and the second guide groove includes a straight segment 3121 and an arc-shaped limiting segment 3122, with the straight end and the arc-shaped limiting segment in a connected state.

[0024] In this embodiment of the invention, the front and rear of the main frame are provided with accommodating cavities 110 for accommodating the expansion unit; a caster assembly 400 is provided at the bottom of the outer side of the expansion unit, and a caster storage groove 120 is provided in the accommodating cavity at the position corresponding to the caster assembly, and the accommodating cavity and the caster storage groove are connected.

[0025] In this embodiment of the invention, a enclosure assembly 500 is detachably disposed between the main frame and the extension unit. The enclosure assembly includes a front plate 501, a rear plate 502, a side plate 503, and a bottom plate 504. The side plate includes a short side plate and a long side plate that are hinged to each other. One end of the bottom plate is hinged to the main frame, and the other end of the bottom plate is hinged to the side plate. Both the front and rear plates are hinged to the bottom plate.

[0026] The upper end of the aforementioned side plate is provided with a slot 505.

[0027] When in the stowed state, the side panel is connected to the expansion unit via locking assembly A600. When in the unfolded state, the front and rear panels are connected to the main frame via locking assembly B610, and the side panel is connected to the expansion unit via locking assembly C620.

[0028] In the storage state, the side panel is used as the lid of the storage box. The locking assembly A600 mentioned above includes an elastic ball retaining structure 601 provided on the front and rear outer sides of the side panel. The elastic ball retaining structure includes a spring 602 and a ball retaining 603. Correspondingly, the front and rear inner sides of the expansion unit are provided with ball retaining grooves 604 for retaining the ball retaining. The elastic ball retaining structure limits the lid and expansion unit, preventing the expansion unit from sliding down under gravity when the transport device is being moved.

[0029] When unlocking is required, simply open the side panel that serves as a cover. At this time, the elastic ball retainer structure receives external force and leaves the ball retainer groove. Lift the main frame or indirectly lift the main frame by lifting the side panel. Under the action of gravity, the extension unit slides freely down the composite guide groove of the composite guide mechanism. Then, by applying external force (such as foot assistance), the extension unit is rotated outward by about 50 degrees, so that the casters are perpendicular to the ground. Lower the enclosure assembly, install the telescopic pull rod, and it can be expanded into a large-capacity handcart. One side that serves as a cover can be opened to facilitate the retrieval of items in narrow spaces, such as the trunk of a car.

[0030] The aforementioned locking component B610 includes a locking block 611 disposed on the front or rear plate and a locking slot 612 disposed on the main frame. The locking block and the locking slot engage to further fix the front and rear plates to the main frame.

[0031] The aforementioned locking assembly C620 includes a side plate latch 621 disposed on the lower side of the side and an expansion slot 622 disposed on the expansion unit in the unfolded state, wherein the side plate latch and the expansion slot engage with each other.

[0032] A locking assembly H630 is also provided between the front panel, the rear panel, and the expansion unit. The locking assembly H630 includes a locking block H631 disposed on the side of the front panel or the rear panel near the expansion unit, and a locking groove H632 disposed on the side of the expansion unit near the front panel or the rear panel. The locking block H and the locking groove H engage in a locking fit. The locking assembly H is optional and only serves to further secure the unit.

[0033] In this embodiment of the invention, a telescopic handle 700 is installed on the outside of the extension unit; when the device is in the unfolded state, the telescopic handle is installed on the extension unit, and it can be converted into a campervan.

[0034] In this embodiment of the invention, the expansion unit 200 includes two plates 201 arranged one in front of the other, and a connecting plate 202 is provided between the two plates.

[0035] In this embodiment of the invention, the main frame has a U-shaped overall cross-section and a handle groove is provided on its upper part.

[0036] Of course, depending on actual usage needs, it can be expanded into multiple states, and can also be expanded into an outdoor table state. Simply remove the side panels and install them on the main frame to use as an outdoor flat tabletop. You can also add ITG extension panels to expand the tabletop.

[0037] Example 2: Based on Example 1, as follows Figure 22-38 As shown, in this embodiment of the invention, the enclosure assembly 500 includes a front panel (not shown in the figure), a rear panel (not shown in the figure), a side panel 503, and a bottom panel 504. The side panels are hinged to the extension unit. The front and rear panels are flexible fabrics and are respectively connected to the side panels, the extension unit, or the main frame.

[0038] During the unfolding process in this embodiment of the invention, the side panel hinged to the bottom of the extension unit moves along with the extension unit throughout the entire process. Since it is initially angled upwards, this angle is gradually "corrected" as the extension unit rotates clockwise. That is, the side panel moves back to an approximately vertical position, automatically forming the side panel of the platform, after which other components are installed.

[0039] When folded up, the front and back panels can be used as lids.

[0040] In this embodiment of the invention, when in the stored state, the main frame and the side panel are connected via locking component D640; when in the unfolded state, the side panel and the main frame are connected via locking component E650, and the bottom plate and the main frame are connected via locking component F660.

[0041] The aforementioned locking assembly D640 includes a cylindrical protrusion 641 disposed on the upper part of the side plate and a cylindrical slot 642 disposed on the main frame. The cylindrical protrusion and the cylindrical slot engage with each other. In the storage state, the side plate and the main frame are fixed together. The cylindrical protrusion is inserted into the cylindrical slot to prevent the extension unit from sliding down under gravity during the handling and transportation of the device.

[0042] When expansion is needed, unlock the locking component D, open the side panel, and the cylindrical protrusion on the side panel will leave the cylindrical slot. Lift the main frame, and the expansion unit will slide freely along the composite guide groove under the action of external force, allowing the expansion unit to rotate outward by about 50 degrees, so that the casters are perpendicular to the ground. For example, you can lift the main frame by hand and then apply external force (such as foot assistance) to make the expansion unit rotate outward by about 50 degrees, or operate one side at a time, lifting one side of the main frame with one hand and operating the composite movement of the expansion unit with the other hand; finally, install the enclosure component and attach the telescopic rod, and it can be expanded into a large-capacity handcart.

[0043] The aforementioned locking assembly E650 includes a connecting rod 651 hinged to the front and rear of the upper part of the side plate. The connecting rod is hinged to the side plate, and a protrusion 652 is provided at the end of the connecting rod. A fixing groove 653 is provided on the upper part of the main frame to engage with the protrusion, and the protrusion is confined within the fixing groove. A support rod 654 is hinged to the middle of the connecting rod. A support locking point 655 is provided at the lower end of the support rod. The support locking point is arc-shaped, and a support groove 656 is provided in the middle of the main frame. The support locking point engages with the support groove to form a stable support.

[0044] The aforementioned locking assembly F660 includes a pull rope 661 disposed between the main frame and the base plate, which suspends the base plate. The base plate may include a large base plate 5041 and a small base plate 5042 that are hinged to each other. In the installed state, the small base plate is perpendicular or nearly perpendicular to the large base plate. The small base plate is connected to the side plate by Velcro 662 for further reinforcement. At the same time, the small base plate can also be connected to the expansion unit via a locking assembly G670. The locking assembly G includes a latching protrusion 671 disposed on the outside of the small base plate and a latching groove G672 disposed on the inside of the expansion unit. The latching protrusion and the latching groove G engage in a latching fit.

[0045] In this embodiment of the invention, a telescopic handle 700 is installed on the outside of the extension unit.

[0046] Example 3: Based on Example 1, such as Figures 39-40As shown, in this embodiment of the invention, the composite guide mechanism includes a composite guide groove 310 disposed on the extension unit and a first pivot 320 and a second pivot 330 disposed on the main frame. The composite guide groove includes a first guide groove 311 and a second guide groove 312. The first pivot and the second pivot can slide along the first guide groove and the second guide groove, respectively, and the first and second pivots are rotatably engaged with the first and second guide grooves, respectively.

[0047] Unlike in Embodiment 1, the first guide groove is a straight groove, while the second guide groove 312 is an inclined groove or an arc-shaped groove. By pulling outwards from the extension unit, a horizontal outward force is applied to the lower part of the extension unit, which indirectly lifts the main frame to enable the extension unit to unfold.

[0048] Example 4: Based on Example 1, as follows Figures 41-45 As shown, the enclosure assembly includes a side enclosure 801, a front enclosure 802, a rear enclosure 803, and two bottom enclosures 804; two enclosure assemblies are provided, which are respectively located on both sides of the main frame or beside the extension unit.

[0049] In embodiments of the present invention, the transport device can take on the following different forms: (1) Closed storage box The two side extension units fold into the main frame, and the bottom enclosure can be used as a cover. The two side enclosures seal the sides of the main frame. The side enclosures are connected to the extension units via pins, fitting snugly against the sides of the extension units and secured with fasteners. The front and rear enclosures are hinged to the side enclosures and fold inwards. The front and rear enclosures can rotate 90 degrees, fitting snugly against the side enclosures or perpendicular to their inner sides. When folded, they fit snugly against the side enclosures. The bottom enclosure is connected to the bottom side of the main frame via pins and is detachable. When a lid is needed, the bottom enclosure can be detached and placed on top of the main frame as a cover.

[0050] (2) Storage box that opens on one side In scenarios where the top is inconvenient to open or close, such as in a car trunk or under a table where height is limited, one side panel can be opened to create an angle. Then, the front and rear panels can be rotated to be fixedly connected to the expansion unit. At this point, the front and rear panels rotate to be flush with the expansion unit, forming a storage box with one side open at the top.

[0051] (3) Handcart moving device By unfolding the expansion units on both sides relative to the main frame through a composite guide mechanism, the bottom enclosure is installed above the expansion unit and flush with the inner bottom surface of the main frame, the side enclosure is installed on the outer side of the expansion unit, and then the front and rear enclosures are installed between the expansion unit and the side enclosure to form a storage space. Finally, a telescopic handle is installed on the outer side of one of the expansion units.

[0052] (4) Mobile table status If it is necessary to change the handcart moving device in state (3) into the moving table state, simply remove the bottom enclosure and place it on the main frame, remove the side enclosure, connect one end of the side enclosure to the bottom enclosure, for example, the side enclosure and the bottom enclosure are hinged, and then the lower end of the side enclosure is supported by the front and rear enclosures between it and the extension unit. One end of the front and rear enclosures is installed with the side enclosure to form a hinged state, and the other end of the front and rear enclosures is fixed to the extension unit.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A multi-state transport device, characterized in that, It includes a main frame and at least one extension unit disposed on the side of the main frame. The main frame and the extension unit are connected by a composite guide mechanism. In the initial state, the extension unit is folded inside the main frame and forms a small storage space. When the main frame and the extension unit move relative to each other by an external force, the extension unit moves downward relative to the main frame and flips outward to form an extended load-bearing frame.

2. The multi-state transport device according to claim 1, characterized in that, The composite guiding mechanism includes a structure in which a guide groove and a pivot are fitted together.

3. A multi-state transport device according to claim 2, characterized in that, The composite guide mechanism includes a composite guide groove disposed on the extension unit and a first pivot and a second pivot disposed on the main frame. The composite guide groove includes a first guide groove and a second guide groove. The first pivot and the second pivot can slide along the first guide groove and the second guide groove, respectively, and the first pivot and the second pivot are rotatably engaged with the first and the second guide groove, respectively.

4. A multi-state transport device according to claim 3, characterized in that, The first guide groove is a straight groove, and the second guide groove includes a straight section and an arc-shaped limiting section.

5. A multi-state transport device according to claim 1, characterized in that, The main frame is provided with cavities at the front and rear for storing the expansion unit; a caster assembly is provided at the bottom of the outer side of the expansion unit, and a caster storage groove is provided in the cavity corresponding to the position of the caster assembly.

6. A multi-state transport device according to claim 1, characterized in that, It also includes a detachable enclosure component that can be installed between the main frame and the expansion unit; the enclosure component is detachably connected to the main frame and the expansion unit through a locking mechanism to form a small storage space or a large storage space.

7. The multi-state transport device according to claim 6, characterized in that, At least one panel of the enclosure assembly can be detached and installed on the main frame to form a supporting plane, creating a tabletop.

8. A multi-state transport device according to claim 1, characterized in that, It also includes a telescopic handle, which is located on the side or bottom of the transport device and is used to pull the transport device to move when it is in the unfolded state.

9. A method for modifying a multi-state transport device according to any one of claims 1-8, characterized in that, This includes the following: when it is necessary to extend the transport device, force is applied to the transport device or its components, so that the extension unit is guided relative to the main frame by a composite guide mechanism, generating a composite movement including a downward translation component and an outward flipping component, until the extension unit is limited by the composite guide mechanism. At this time, the caster assembly at its bottom forms a support with the ground to form a mobile vehicle with a large storage space.

10. A method for modifying a multi-state transport device according to any one of claims 1-8, characterized in that, This includes the following: when it is necessary to reduce the size of the transport device, the locking of the enclosure assembly is released; force is applied to the transport device or its components, so that the expansion unit is guided relative to the main frame by a composite guide mechanism, generating a composite movement including an inward flipping component and an upward translation component, until it is retracted into the main frame to form a small storage space.

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