Frameless flat folding cart underframe structure

Abstract

The utility model discloses an underframe structure of a frameless flat folding trolley, and belongs to the technical field of trolleys. The device mainly comprises four groups of vertical rods, wherein the four groups of vertical rods comprise front vertical rods and rear vertical rods; the bottom sleeve is mounted at the bottom end of the vertical rod; the first cross rod and the second cross rod are mounted between the bottom sleeves; the first fixing ring is mounted at the bottom end of the front vertical rod; the second fixing ring is mounted at the bottom end of the rear vertical rod; the first vertical rod is rotationally arranged, and the second vertical rod is rotationally arranged; the hinge sleeve is mounted on the second vertical rod and hinged to the first vertical rod; the first rotating ring and the second rotating ring are mounted on the vertical rod; the first inclined rod is mounted on the first rotating ring; the second inclined rod is mounted on the second rotating ring; and the folding assembly is used for supporting the bottom of the cart. According to the chassis structure of the frameless flat folding trolley, the folding assembly is arranged, so that the whole trolley does not rise in the folding process of the trolley, and the trolley storage difficulty is further reduced.

Description

Technical Field

[0001] This application relates to the technical field of trolleys, and specifically relates to a frameless flat-fold trolley chassis structure. Background Art

[0002] A trolley is a manually pushed or pulled handling vehicle, which is the ancestor of all vehicles. Although the material handling technology of trolleys has been continuously developing, trolleys are still used as an indispensable handling tool. Trolleys are widely used in production and life because they are inexpensive, easy to maintain, convenient to operate, light in weight, can work in places where motor vehicles are inconvenient to use, and are very convenient for handling lighter items over short distances.

[0003] For example, the patent with the publication number CN115583274 A specifically discloses a gathering-type folding trolley. Through the Y-shaped folding components of the front wall and the rear wall, the foldability of the side walls, and the foldability of the chassis, multiple surfaces can be gathered and stored, achieving a high gathering of the volume after storage and a smaller volume, thus facilitating the storage and placement of the trolley.

[0004] In the implementation process of the above patent, although the trolley can be folded to reduce the occupied space, when the above-mentioned trolley is folded, its overall height will increase compared to when it is unfolded, resulting in the trolley occupying more space in the height direction after folding. Therefore, it is necessary to provide a frameless flat-fold trolley chassis structure to solve the above problems.

[0005] It should be noted that the above information disclosed in this background art section is only used to understand the background art of the concept of this application, and therefore, it may include information that does not constitute the prior art. Summary of the Invention

[0006] Based on the above problems existing in the prior art, the problem to be solved by this application is: to provide a frameless flat-fold trolley chassis structure, which solves the problem of the increased height of the trolley after folding.

[0007] The technical solution adopted by this application to solve its technical problems is: a frameless flat-fold trolley chassis structure, including.

[0008] Further, an extension mechanism is provided at the upper end of the vertical rod. The extension mechanism includes an extension block inserted at the upper outer side of the vertical rod. A through elliptical groove is provided inside the vertical rod, and a transition rod is slidably arranged inside the elliptical groove. An extension rod is installed inside the transition rod; a spring is installed between the bottom of the transition rod and the elliptical groove. A limiting step is provided at the inner bottom end of the extension block, which divides the inner part of the extension block into a first section at the lower end and a second section at the upper end. The size of the first section matches that of the transition rod, while the size of the second section is smaller than that of the transition rod; a convex platform is provided at the bottom of the transition rod, and a slideway matching the convex platform is provided at the first section of the extension block

[0009] Further, a horizontal through groove is provided at the upper end of the extension block, and a limiting block is slidably arranged inside the through groove. The outer end of the limiting block extending out of the vertical rod forms a button, and an elastic part is installed between the limiting block and the vertical rod. A limiting groove is provided on the limiting block; a square platform is provided at the upper end of the extension rod.

[0010] Further, the wheel mechanism includes a wheel frame detachably installed at the lower end of the front vertical rod. A front wheel is rotatably arranged on the wheel frame. A connecting seat is detachably installed at the lower end of the rear vertical rod, and a rear wheel is rotatably installed on the connecting seat; a connecting shaft is rotatably connected between the two groups of connecting seats, and a foot brake is provided on the connecting shaft.

[0011] Further, a traction mechanism is provided on the first cross bar. The traction mechanism includes a fixed seat installed on the first cross bar, and a bottom pull rod is rotatably arranged on the fixed seat; a sliding cavity is provided on the bottom pull rod, and a top pull rod is slidably installed inside the sliding cavity. A handle is installed at the top end of the top pull rod; a pull sleeve is sleeved on the bottom pull rod, and a locking part is provided on the pull sleeve.

[0012] Further, a protective sleeve is provided at the lower end of the vertical rod. A second arc groove is provided at the upper end of the protective sleeve, and a horizontal first arc groove is provided at the lower end of the protective sleeve.

[0013] Further, a connecting end is provided at the top end of the extension rod, and a ceiling mechanism is provided at the top of the connecting end. The ceiling mechanism includes a top sleeve detachably sleeved on the connecting end. A rotating sleeve is rotatably arranged on the top sleeve, and a top rod is inserted on the rotating sleeve.

[0014] Further, four groups of the top rods are commonly connected with an insertion block at positions far from the rotating sleeve, and a socket is rotatably connected to the insertion block. The socket is connected to the position of the top rod far from the rotating sleeve.

[0015] Further, a supporting mechanism is installed at the top of the rear vertical rod. The supporting mechanism includes a female ring installed on the extension block. Multiple groups of card slots are arranged on the female ring along the circumferential direction, and a male ring is arranged on one side of the female ring.

[0016] An insertion rod is arranged on the male ring, and a jack cooperating with the insertion rod is arranged on the female ring.

[0017] An extension sleeve is arranged on the male ring, a bent rod is inserted into the extension sleeve, and a handrail is sleeved between the two bent rods.

[0018] The bottom frame structure of the borderless flat-fold trolley provided by this application has the following beneficial effects:

[0019] 1. By setting up a folding component, the trolley is suitable for being in a deployed and folded state, and at the same time has a smaller volume when folded, thus facilitating the storage of the trolley. Moreover, during the folding process of the trolley, the overall height of the trolley does not increase, thereby further reducing the difficulty of storing the trolley.

[0020] 2. By setting up an extension mechanism, the top of the trolley can be extended and expanded, and a ceiling mechanism is installed to protect the trolley.

[0021] 3. By setting up a supporting mechanism, the staff can manually support the trolley, so that when handling heavier goods, multiple people can operate together, reducing the difficulty of handling the goods.

[0022] In addition to the purposes, features and advantages described above, this application has other purposes, features and advantages. The following will refer to the drawings to make a further detailed description of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The schematic diagrams in the specification that form a part of this application are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application.

[0024] In the drawings:

[0025] Figure 1 is the overall schematic diagram of a bottom frame structure of a borderless flat-fold trolley in this application Figure 1 ;

[0026] Figure 2 is the overall schematic diagram of a bottom frame structure of a borderless flat-fold trolley in this application Figure 2 ;

[0027] Figure 3 is Figure 2 the exploded schematic diagram of the overall structure in

[0028] Figure 4 is Figure 1 Partial structural schematic diagram at position A in

[0029] Figure 5 is Figure 2 Partial structural schematic diagram at position B in

[0030] Figure 6 is Figure 3 Partial structural schematic diagram at position C in

[0031] Figure 7 is Figure 3 Partial structural schematic diagram at position D in

[0032] Figure 8 is Figure 3 Partial structural schematic diagram at position E in

[0033] Figure 9 is Figure 3 Partial structural schematic diagram at position F in

[0034] Figure 10 is Figure 3 Partial structural schematic diagram at position G in

[0035] Among them, each reference numeral in the figure:

[0036] 1. Frame mechanism; 11. Vertical rod; 12. First vertical rod; 13. Second vertical rod; 14. Hinge sleeve; 15. First cross bar; 16. Side cross bar; 17. Middle vertical rod; 18. Middle cross bar; 19. Protective sleeve; 191. First arc groove; 192. Second arc groove; 110. First diagonal rod; 111. Second diagonal rod; 112. Upper sleeve; 113. Lower sleeve; 114. Upper rod; 115. Lower rod; 116. Middle shaft; 117. Clamping sleeve; 118. Lower ring sleeve; 119. Upper rotating shaft; 120. Connecting rod; 121. Transition sleeve; 123. Bottom sleeve; 124. Fixed ring; 125. Rotating ring; 126. Second cross bar;

[0037] 2. Extension mechanism; 21. Extension rod; 211. Square platform; 212. Connection end; 22. Extension block; 221. Through groove; 23. Female ring; 231. Card slot; 24. Limit block; 241. Button; 242. Limit groove; 25. Transition rod; 251. Notch; 252. Boss; 26. Spring; 27. Cover plate; 28. Male ring; 281. Card teeth; 282. Extension sleeve; 283. Insert rod;

[0038] 3. Wheel mechanism; 31. Front wheel; 32. Rear wheel; 33. Wheel frame; 34. Connection seat; 35. Foot brake; 36. Connection shaft;

[0039] 4. Traction mechanism; 41. Bottom drawbar; 42. Top drawbar; 43. Handle; 44. Pulling sleeve; 45. Locking part; 46. Fixed seat;

[0040] 5. Support mechanism; 51. Bent rod; 52. Armrest;

[0041] 6. Ceiling mechanism; 61. Top rod; 62. Insert block; 63. Top sleeve; 64. Rotating sleeve; 65. Insert sleeve. Detailed implementation manners

[0042] It should be noted that, without conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The following will describe the present application in detail with reference to the drawings and in combination with the embodiments.

[0043] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0044] Embodiment 1:

[0045] This embodiment elaborates on the structure and folding principle of the trolley. Specifically:

[0046] As Figure 1 shown, the present application provides a frameless flat-fold trolley chassis structure, including a frame mechanism 1. The frame mechanism 1 is the main part of the trolley and is used to carry goods. The frame mechanism 1 includes four groups of vertical rods 11. For the convenience of description, taking the view in Figure 1 as an example, along the advancing direction of the trolley, the two groups of vertical rods 11 on the left side are defined as front vertical rods, and the two groups of vertical rods 11 on the right side are defined as rear vertical rods;

[0047] As Figures 1 - 3 and Figure 6 shown, bottom sleeves 123 are fixedly installed at the bottom ends of the four groups of vertical rods 11. A first crossbar 15 is fixedly installed between the two bottom sleeves 123 on the front vertical rods, and a second crossbar 126 is fixedly installed between the two bottom sleeves 123 on the rear vertical rods. Thus, the two front vertical rods are connected by the first crossbar 15, and the two rear vertical rods are connected by the second crossbar 126 to form a stable whole;

[0048] At the bottom ends of both sets of front vertical rods and both sets of rear vertical rods, fixing rings 124 are fixedly arranged. For convenience of description, the fixing ring 124 connected to the front vertical rod is defined as the first fixing ring, and the fixing ring 124 connected to the rear vertical rod is defined as the second fixing ring;

[0049] And a first vertical rod 12 is rotatably arranged on the first fixing ring, so that the first vertical rod 12 can rotate in the vertical direction around the first fixing ring. At the same time, a second vertical rod 13 is rotatably arranged on the second fixing ring, so that the second vertical rod 13 can rotate in the vertical direction around the second fixing ring;

[0050] Continue to refer to Figures 1 - 3 and Figure 6 , an articulated sleeve 14 is installed at a position of the second vertical rod 13 away from the second fixing ring. The articulated sleeve 14 is articulated with one end of the first vertical rod 12 away from the first fixing ring, so that the first vertical rod 12 and the second vertical rod 13 can rotate relative to each other and are both in a horizontal state to make the trolley in the unfolded state, and are both in a vertical state to make the trolley in the stored state;

[0051] As Figure 1 - Figure 2 shown, side crossbars 16 and middle crossbars 18 are fixedly installed between the two sets of first vertical rods 12 and the two sets of second vertical rods 13. Among them, the side crossbars 16 are located at positions close to the vertical rods 11, and the middle crossbars 18 are located at positions close to the articulated sleeves 14. Thus, through the side crossbars 16 and the middle crossbars 18, the two sets of vertical rods can be kept stable;

[0052] At the same time, two sets of middle vertical rods 17 are fixedly installed between the side crossbars 16 and the middle crossbars 18. The two sets of middle vertical rods 17 are symmetrically arranged to further strengthen the stability of the trolley;

[0053] As Figure 4 and Figure 6 shown, a rotating ring 125 is rotatably arranged at a position on the vertical rod 11 between the bottom sleeve 123 and the fixing ring 124. For convenience of description, the rotating ring 125 installed on the front vertical rod is defined as the first rotating ring, and the rotating ring 125 installed on the rear vertical rod is defined as the second rotating ring. At the same time, there is one set of the first rotating ring and the second rotating ring respectively, and they are on the front vertical rod and the rear vertical rod arranged diagonally;

[0054] At the same time, a first inclined rod 110 is fixedly installed on the first rotating ring. The first inclined rod 110 is adapted to rotate in the horizontal direction around the front vertical rod along with the first rotating ring, and a second inclined rod 111 is fixedly installed on the second rotating ring. The second inclined rod 111 is adapted to rotate in the horizontal direction around the rear vertical rod along with the second rotating ring;

[0055] In this embodiment, a folding assembly is connected to the other ends of the first diagonal rod 110 and the second diagonal rod 111. The folding assembly is adapted to fold together with the trolley and support the bottom of the trolley when the trolley is in the unfolded state;

[0056] As Figure 4 shown, the folding assembly includes a fixed shaft (not marked in the figure) fixedly installed on the first diagonal rod 110 and the second diagonal rod 111. An upper sleeve 112 is rotatably installed at the upper end of the fixed shaft. At the same time, an upper rod 114 is fixedly installed between the two groups of upper sleeves 112. And two groups of clamping sleeves 117 are fixedly arranged on the upper rod 114. A first opening (not marked in the figure) is arranged at the upper end of the clamping sleeve 117. The first opening is adapted to be clamped on the middle cross bar 18 to facilitate fixing the folding assembly;

[0057] At the same time, a lower sleeve 113 is rotatably installed at the lower end of the fixed shaft. At the same time, a lower rod 115 is fixedly installed between the two groups of lower sleeves 113. A middle shaft 116 is rotatably installed between the middle part of the lower rod 115 and the middle part of the upper rod 114, so as to connect the lower rod 115 and the upper rod 114 through the middle shaft 116;

[0058] In summary, when the trolley is in use, the first vertical rod 12 and the second vertical rod 13 are in a horizontal state. At the same time, the first opening of the clamping sleeve 117 is snapped onto the middle cross bar 18. At this time, the trolley is in the unfolded state to facilitate the loading of goods;

[0059] When the trolley is not in use, the staff pulls the middle cross bar 18 upward so that the middle cross bar 18 comes out of the clamping sleeve 117. The first vertical rod 12 and the second vertical rod 13 rotate relative to each other and are in a vertical state. At this time, the trolley is in the folded state to be in a smaller volume, thus facilitating the storage of the trolley. And during the folding process of the trolley, the overall height of the trolley does not increase, thereby further reducing the difficulty of storing the trolley.

[0060] As another embodiment of the folding assembly, as Figure 5 shown, the folding assembly includes a lower ring sleeve 118 fixedly installed on the first diagonal rod 110 and the second diagonal rod 111. An upper rotating shaft 119 is rotatably arranged on the lower ring sleeve 118. At the same time, a connecting rod 120 is fixedly installed between the two groups of upper rotating shafts 119. Two groups of transition sleeves 121 are fixedly arranged on the connecting rod 120. A second opening (not marked in the figure) is arranged at the upper end of the transition sleeve 121. The second opening is adapted to be clamped on the middle cross bar 18 to facilitate fixing the folding assembly.

[0061] As Figure 6As shown in the figure, a protective sleeve 19 is fixedly arranged at the lower end of the vertical rod 11. The protective sleeve 19 is located outside the fixed ring 124 and the rotating ring 125, and is used to protect the two. At the same time, a second arc groove 192 is arranged at the upper end of the protective sleeve 19, and the second arc groove 192 is used to avoid the connection between the first vertical rod 12 and the fixed ring 124. And a horizontal first arc groove 191 is arranged at the lower end of the protective sleeve 19, and the first arc groove 191 is used to avoid the first diagonal rod 110 (the second diagonal rod 111) when it rotates.

[0062] To facilitate the movement of the trolley, as Figures 1 - 3 shown, a wheel mechanism 3 is installed at the bottom of the vertical rod 11. The wheel mechanism 3 is used to drive the trolley to move or lock. The wheel mechanism 3 includes a wheel frame 33 detachably installed at the lower end of the front vertical rod. A front wheel 31 is rotatably arranged on the wheel frame 33. At the same time, a connecting seat 34 is detachably installed at the lower end of the rear vertical rod, and a rear wheel 32 is rotatably installed on the connecting seat 34. Thus, the trolley can be driven to move through the cooperation of the front wheel 31 and the rear wheel 32;

[0063] To brake the trolley, a connecting shaft 36 is rotatably connected between the two groups of connecting seats 34. At the same time, a foot brake 35 is arranged on the connecting shaft 36. The foot brake 35 is used to facilitate the staff to step on, so as to brake the rear wheel 32;

[0064] It should be noted that the structure and principle of using the foot brake 35 to brake the rear wheel 32 can refer to the patent with the publication number of CN214451255 U, and will not be elaborated here;

[0065] To facilitate the staff to operate the trolley, as Figures 1 - 3 shown, a traction mechanism 4 is arranged on the first cross bar 15. The traction mechanism 4 is used for the staff to hold, so as to facilitate the movement of the trolley. The traction mechanism 4 includes a fixed seat 46 fixedly installed on the first cross bar 15. A bottom pull rod 41 is rotatably arranged on the fixed seat 46. Thus, the bottom pull rod 41 can rotate around the first cross bar 15 to facilitate the adjustment of the traction angle;

[0066] At the same time, a sliding cavity (not shown in the figure) is opened at the position of the bottom pull rod 41 far from the first cross bar 15. A top pull rod 42 is slidably installed in the sliding cavity. The top pull rod 42 is adapted to slide in the sliding cavity, so as to extend out of the sliding cavity when the trolley is unfolded and be received in the sliding cavity when the trolley is folded. Thus, the occupied volume of the top pull rod 42 can be reduced. The top of the top pull rod 42 is fixedly installed with a handle 43, and the handle 43 is used to facilitate the staff to hold and operate;

[0067] A pull sleeve 44 is fixedly sleeved on the bottom pull rod 41. The pull sleeve 44 is located at the opening of the sliding cavity. Meanwhile, a locking portion 45 is provided on the pull sleeve 44. The locking portion 45 is adapted to penetrate through the pull sleeve 44 and the bottom pull rod 41 and extend into the sliding cavity to abut against the top pull rod 42, and the locking portion 45 is adapted to be relaxed to move away from the top pull rod 42 so that the top pull rod 42 can slide within the sliding cavity, thus realizing the sliding and locking of the top pull rod 42 inside the bottom pull rod 41.

[0068] Embodiment 2:

[0069] During the use of the handcart, it is often necessary to be applied in some special occasions, such as being used as a temporary sales point. At this time, it is necessary to install a canopy to block sunlight or prevent rain. However, the temporary addition often requires additional rods to be added by the staff for fixation, thus increasing the difficulty of on-site operation;

[0070] To solve the above problems, as Figure 1 - Figure 3 shown, an extension mechanism 2 is provided at the upper end of the vertical rod 11. The extension mechanism 2 is used to expand the vertical rod 11 so as to add appropriate accessories to the upper end of the vertical rod 11;

[0071] As Figure 1 - Figure 3 and Figure 7 shown, the extension mechanism 2 includes an extension block 22 fixedly inserted at the upper outer side of the vertical rod 11. Meanwhile, a through elliptical groove (not marked in the figure) is provided inside the vertical rod 11, and a transition rod 25 is slidably arranged inside the elliptical groove. Thus, the transition rod 25 can slide vertically inside the elliptical groove. It should be noted that an extension rod 21 is fixedly installed inside the transition rod 25, so that the extension rod 21 can move synchronously with the transition rod 25;

[0072] Meanwhile, a spring 26 is fixedly installed between the bottom of the transition rod 25 and the elliptical groove. Thus, in the initial state, the transition rod 25 can be at the upper end of the vertical rod 11 under the action of the spring 26;

[0073] And a limiting step (not shown in the figure) is provided at the inner bottom end of the extension block 22. The limiting step divides the inner part of the extension block 22 into a first section at the lower end and a second section at the upper end. The size of the first section matches that of the transition rod 25, while the size of the second section is smaller than that of the transition rod 25. Thus, the transition rod 25 can be blocked from coming out of the vertical rod 11 through the limiting step;

[0074] Continue to refer to Figure 7, a boss 252 is provided at the bottom of the transition rod 25, and at the same time, a slideway (not shown in the figure) matching the boss 252 is provided at the first section of the extension block 22, so that when the transition rod 25 slides to the upper end of the vertical rod 11, the cooperation between the slideway and the boss 252 can make the sliding of the transition rod 25 more stable;

[0075] In order to fix the position of the extension rod 21, as Figure 7 and Figure 9 shown, a horizontal through groove 221 is provided at the upper end of the extension block 22. A limiting block 24 is slidably arranged in the through groove 221. The outer end of the limiting block 24 extends out of the vertical rod 11 to form a button 241, and an elastic part (not shown in the figure) is installed between the limiting block 24 and the vertical rod 11. It should be noted that a limiting groove 242 is provided on the limiting block 24, so that when the elastic part is pressed, the limiting groove 242 is aligned with the axis of the transition rod 25, and a notch 251 is provided at the upper end of the transition rod 25, so that when the elastic part is in the initial state, the limiting block 24 can be stuck into the notch 251 to facilitate the limitation of the transition rod 25;

[0076] At the same time, a square platform 211 is provided at the upper end of the extension rod 21, so that when the elastic part is in the initial state, it can also be located at the upper end of the square platform 211 and limit the extension rod 21;

[0077] It can be understood that in the initial state, the extension rod 21 is received in the vertical rod 11. At this time, the limiting block 24 overlaps on the upper end of the square platform 211 to limit the position of the extension rod 21;

[0078] When the extension rod 21 needs to be pulled out, press the button 241 to align the limiting groove 242 with the axis of the transition rod 25. At this time, the limitation of the extension rod 21 by the limiting block 24 disappears, and the transition rod 25 moves upward under the drive of the spring 26, driving the extension rod 21 to move upward synchronously and reach the highest point position;

[0079] At this time, release the button 241. After the limiting block 24 resets, it is stuck into the notch 251, so as to limit the extension rod 21 in the extended state to maintain the stability of the extension rod 21.

[0080] As Figure 1 and Figures 9 - 10 shown, a connection end 212 is provided at the top of the extension rod 21. A ceiling mechanism 6 is provided at the top of the connection end 212. The ceiling mechanism 6 is used to place a tent at the top of the trolley. The ceiling mechanism 6 includes a top sleeve 63 detachably sleeved on the connection end 212. At the same time, a rotating sleeve 64 is rotatably arranged on the top sleeve 63, and a top rod 61 is inserted on the rotating sleeve 64;

[0081] At the same time, the four groups of top rods 61 are commonly connected to a plug block 62 at a position away from the rotating sleeve 64. The plug block 62 is rotatably connected to a plug sleeve 65, and the plug sleeve 65 is sleeved on the position of the top rod 61 away from the rotating sleeve 64, so that the four groups of top rods 61 are firmly connected together through the plug block 62, so as to fix the tent and provide shielding and protection for the cart.

[0082] like Figures 2 - 3 and Figure 8 As shown, a supporting mechanism 5 is installed at the top of the rear upright, which includes a female ring 23 fixedly mounted on an extension block 22 at the rear upright position. The female ring 23 is provided with multiple groups of slots 231 along the circumferential direction. At the same time, a male ring 28 is provided on one side of the female ring 23. The male ring 28 is provided with latching teeth 281 that cooperate with the slots 231 along the circumferential direction. The male ring 28 is engaged with the female ring 23 through the engagement of the latching teeth 281 and the slots 231.

[0083] At the same time, a plug rod 283 is fixedly provided on the male ring 28, and a socket (not shown in the figure) that cooperates with the plug rod 283 is provided on the female ring 23, so that the plug rod 283 can be inserted into the socket to guide the male ring 28 and the female ring 23 when they are connected;

[0084] A cover plate 27 is installed on one side of the male ring 28 to seal the side of the male ring 28 .

[0085] Continue to refer Figure 8 An extension sleeve 282 is provided on the male ring 28, and a curved rod 51 is inserted into the extension sleeve 282. At the same time, a handrail 52 is provided between the two sets of curved rods 51. The handrail 52 is suitable for connecting the two sets of curved rods 51, so that the staff can manually hold the handrail 52 to assist in pushing the trolley;

[0086] It should be noted that an elastic member is provided between the curved rod 51 and the armrest 52, so that the curved rod 51 can slide inside the armrest 52. When the angle of the curved rod 51 needs to be adjusted, the two groups of curved rods 51 can be brought close to each other, thereby separating the male ring 28 and the female ring 23 from each other. Then the male ring 28 is rotated relative to the female ring 23, and the angle can be adjusted by using the locking teeth 281 in different positions to cooperate with the locking grooves 231 to achieve the purpose of adapting to the operation of different staff.

[0087] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An edgeless flat-foldable trolley underframe structure, characterized in that: Comprising: Four groups of vertical rods (11) as supports, and the four groups of vertical rods (11) are divided into two groups of front vertical rods and two groups of rear vertical rods; Bottom sleeves (123) installed at the bottom ends of the vertical rods (11); A first cross bar (15) and a second cross bar (126) installed between the bottom sleeves (123); A first fixing ring installed at the bottom end of the front vertical rod and a second fixing ring installed at the bottom end of the rear vertical rod; A first vertical rod (12) rotatably arranged on the first fixing ring, and a second vertical rod (13) rotatably arranged on the second fixing ring; A hinge sleeve (14) installed on the second vertical rod (13), and the hinge sleeve (14) is hinged to the first vertical rod (12); A first rotating ring installed on the front vertical rod, and a second rotating ring installed on the rear vertical rod; A first inclined rod (110) installed on the first rotating ring, and a second inclined rod (111) installed on the second rotating ring; A wheel mechanism (3) for driving the cart to move; A traction mechanism (4) for a staff member to hold; And A folding assembly for supporting the bottom of the cart in the unfolded state of the cart, and the folding assembly includes: A fixed shaft fixedly installed on the first inclined rod (110) and the second inclined rod (111), an upper sleeve (112) is rotatably installed at the upper end of the fixed shaft, an upper rod (114) is installed between the two upper sleeves (112), two clamping sleeves (117) are arranged on the upper rod (114), and a first opening is arranged at the upper end of the clamping sleeve (117); A lower sleeve (113) is rotatably installed at the lower end of the fixed shaft, a lower rod (115) is installed between the two lower sleeves (113), and a middle shaft (116) is rotatably installed between the middle part of the lower rod (115) and the middle part of the upper rod (114).

2. The structure of the bottom frame of a borderless flat-foldable trolley according to claim 1, characterized in that: An extension mechanism (2) is arranged at the upper end of the vertical rod (11), and the extension mechanism (2) includes an extension block (22) inserted into the upper end of the outer side of the vertical rod (11), an elliptical groove is arranged in the vertical rod (11) in a penetrating manner, a transition rod (25) is slidably arranged in the elliptical groove, and an extension rod (21) is installed in the transition rod (25); A spring (26) is installed between the bottom of the transition rod (25) and the elliptical groove, a limiting step is arranged at the inner bottom end of the extension block (22), and the inner part of the extension block (22) is divided into a first section at the lower end and a second section at the upper end by the limiting step, wherein the size of the first section matches that of the transition rod (25), and the size of the second section is smaller than that of the transition rod (25); A convex platform (252) is arranged at the bottom of the transition rod (25), and a sliding track matching the convex platform (252) is arranged at the first section of the extension block (22).

3. The bottom frame structure of a borderless flat-foldable trolley according to claim 2, characterized in that: A horizontal through groove (221) is provided at the upper end of the extension block (22). A limit block (24) is slidably arranged in the through groove (221). The outer end of the limit block (24) protruding from the vertical rod (11) forms a button (241). An elastic part is installed between the limit block (24) and the vertical rod (11). A limit groove (242) is provided on the limit block (24). A square platform (211) is provided at the upper end of the extension rod (21).

4. The structure of the bottom frame of a borderless flat-foldable trolley according to claim 3, characterized in that: The wheel mechanism (3) includes a wheel frame (33) detachably installed at the lower end of the front vertical rod. A front wheel (31) is rotatably arranged on the wheel frame (33). A connecting seat (34) is detachably installed at the lower end of the rear vertical rod. A rear wheel (32) is rotatably installed on the connecting seat (34). A connecting shaft (36) is rotatably connected between two groups of the connecting seats (34). A foot brake (35) is provided on the connecting shaft (36).

5. The structure of a frameless flat-foldable trolley chassis according to claim 4, characterized in that: A traction mechanism (4) is provided on the first cross bar (15). The traction mechanism (4) includes a fixed seat (46) installed on the first cross bar (15). A bottom pull rod (41) is rotatably arranged on the fixed seat (46). A sliding cavity is provided on the bottom pull rod (41). A top pull rod (42) is slidably installed in the sliding cavity. A handle (43) is installed at the top end of the top pull rod (42). A pull sleeve (4|4) is sleeved and installed on the bottom pull rod (41). A locking part (45) is provided on the pull sleeve (44).

6. The bottom frame structure of a borderless flat-foldable trolley according to claim 5, characterized in that: A protective sleeve (19) is provided at the lower end of the vertical rod (11). A second arc groove (192) is provided at the upper end of the protective sleeve (19). A horizontal first arc groove (191) is provided at the lower end of the protective sleeve (19).

7. The bottom frame structure of a borderless flat-foldable trolley according to claim 6, characterized in that: A connecting end (212) is provided at the top end of the extension rod (21). A ceiling mechanism (6) is provided at the top of the connecting end (212). The ceiling mechanism (6) includes a top sleeve (63) detachably sleeved on the connecting end (212). A rotating sleeve (64) is rotatably arranged on the top sleeve (63). A top rod (61) is inserted into the rotating sleeve (64).

8. The structure of the bottom frame of a borderless flat-foldable trolley according to claim 7, characterized in that: Four groups of the top rods (61) are commonly connected with an insertion block (62) at a position far from the rotating sleeve (64). An insertion sleeve (65) is rotatably connected to the insertion block (62). The insertion sleeve (65) is connected to the position of the top rod (61) far from the rotating sleeve (64).

9. The structure of a frameless flat-foldable trolley underframe according to claim 8, characterized in that: A supporting mechanism (5) is installed at the top end of the rear vertical rod. The supporting mechanism (5) includes a female ring (23) installed on the extension block (22). A plurality of groups of card slots (231) are provided on the female ring (23) along the circumferential direction. A male ring (28) is provided on one side of the female ring (23). An insertion rod (283) is provided on the male ring (28). A jack cooperating with the insertion rod (283) is provided on the female ring (23). An extension sleeve (282) is provided on the male ring (28). A bent rod (51) is inserted into the extension sleeve (282). An armrest (52) is sleeved between two groups of the bent rods (51).

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