A flatbed cart

Abstract

The present invention discloses a flatbed cart, comprising a support plate and a push handle; a guide rail is symmetrically arranged on both sides of the bottom of the support plate; the push handle comprises a pushing portion and two fixing portions respectively hinged at both ends of the pushing portion; the two ends of the pushing portion and the two fixing portions can be slidably mounted on two guide rails respectively; two positioning blocks are also arranged at the bottom of the support plate for limiting the two fixing portions respectively; when the pushing portion is pulled outward until the positioning block limits the fixing portion, the pushing portion extends out of the support plate. The present invention has a simple and reasonable structure and is easy to use. The push handle can be conveniently stored at the bottom of the support plate and is not easily damaged. It can also reduce the volume of the flatbed cart, which is convenient for storage and transportation.

Description

Technical Field

[0001] The present invention relates to the technical field of transport equipment, and in particular to a flatbed cart. Background Art

[0002] A flatbed trolley is a small material transport device that is widely used in production and life. It is inexpensive, easy to maintain, easy to operate, and lightweight. It can work in places where motor vehicles are inconvenient to use and is very convenient for transporting items over short distances. Due to its ease of use, it is widely used for short-distance transportation in warehouses, manufacturing plants, department stores, logistics centers, freight stations, or during distribution.

[0003] The existing flatbed cart generally includes a support plate, a push handle and casters respectively connected to the support plate. However, the existing push handle is generally fixedly connected to one side of the support plate and cannot be stored, which results in a large overall size of the flatbed cart, which is not conducive to storage and transportation. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art, the object of the present invention is to provide a flatbed cart with a simple and reasonable structure, easy to use, and a handle that can be conveniently stored at the bottom of the support plate, is not easy to be damaged, and can reduce the volume of the flatbed cart, which is convenient for storage and transportation.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] A flatbed cart comprises a support plate and a push handle, wherein a guide rail is symmetrically arranged on both sides of the bottom of the support plate; the push handle comprises a pushing part and two fixing parts respectively hinged at both ends of the pushing part; the two ends of the pushing part and the two fixing parts are respectively slidably installed on two guide rails; two positioning blocks are also arranged at the bottom of the support plate for limiting the positions of the two fixing parts respectively; when the pushing part is pulled outward until the positioning block limits the position of the fixing part, the pushing part extends out of the support plate.

[0007] The additional structure of the above technical solution also includes the following solutions:

[0008] As a specific embodiment, each of the guide rails includes a connecting portion for connecting to the support plate and a "T"-shaped limiting portion arranged at the lower end of the connecting portion; and "T"-shaped limiting grooves for correspondingly sleeved on the limiting portion are respectively provided on both ends of the pushing portion and the two fixed portions.

[0009] As a specific embodiment, an insert block is respectively provided at both ends of the pushing part; a slot matching the insert block is respectively provided at the front end of the two fixing parts; corresponding sockets are respectively provided on both sides of the insert block and the slot, and bolts are horizontally installed in the sockets to hinge the insert block with the fixing part.

[0010] As a specific embodiment, the flatbed cart also includes at least two caster folding assemblies; two fixed tubes extending forward and backward are symmetrically arranged at the bottom of the support plate, and a sliding tube that can slide along the length direction of the fixed tube is respectively provided in the two fixed tubes; the caster folding assembly is correspondingly installed on the two fixed tubes and the two sliding tubes; the two positioning blocks are respectively installed at the front ends of the two sliding tubes, and the two positioning blocks respectively cooperate with the two caster folding assemblies and the push handle.

[0011] Furthermore, each of the caster folding components includes a caster fixing seat rotatably mounted on the fixing tube, a caster connected to one side of the caster fixing seat and a pin fixed to the outer wall of the sliding tube; a first strip hole is provided on the fixing tube for the pin to move forward and backward; an arc track for guiding the caster fixing seat is provided inside the caster fixing seat, and the pin is inserted in the arc track; an opening positioning groove and a folding positioning groove are respectively provided at both ends of the arc track; when the push handle is pulled outward, the push handle drives the positioning block to move forward, and simultaneously drives the pin to move along the arc track from back to front, and when the pin is embedded in the opening positioning groove, the caster is changed from a folded state to an opened state; when the push handle is pushed inward, the push handle drives the positioning block to move backward, and simultaneously drives the pin to move along the arc track from front to back, and when the pin is embedded in the folding positioning groove, the caster is changed from an opened state to a folded state.

[0012] Furthermore, a front positioning frame bar is provided on the front side of the support plate; a positioning strip-shaped hole is provided on the front positioning frame bar, the push handle is matchedly inserted into the positioning strip-shaped hole, and the front positioning frame bar is used to block the positioning block.

[0013] Furthermore, a step is provided on both sides of the front end of each positioning block; the front end of the positioning block can be inserted into the positioning bar-shaped hole, and the positioning block can be engaged with the front positioning frame bar through the two steps.

[0014] Furthermore, the caster fixing seat includes an inner fixing seat and an outer fixing seat; the inner fixing seat is sleeved on the outer wall of the fixing tube; a first arcuate surface extending from back to front is provided at the front end of the inner fixing seat, and the folding positioning groove is connected to the rear end of the first arcuate surface; the outer fixing seat is cooperatively sleeved on the inner fixing seat and the fixing tube, and the caster is connected to one side of the outer fixing seat; a second arcuate surface matching the first arcuate surface and extending from back to front is provided inside the outer fixing seat, and the opening positioning groove is connected to the front end of the second arcuate surface; the arc track is formed between the first arcuate surface and the second arcuate surface.

[0015] Furthermore, each of the caster folding assemblies also includes a guide locking assembly arranged behind the caster fixing seat and cooperating with the caster fixing seat; a locking block is respectively arranged on the outer walls of both sides of the inner fixing seat, and a locking groove with a rear end opening is respectively arranged on each of the locking blocks; the guide locking assembly includes a guide rod installed on the sliding tube and a guide member fixedly mounted on the fixing tube; the two ends of the guide rod are respectively passed through the outside of the sliding tube, and a second strip hole for the two ends of the guide rod to move forward and backward is provided on the fixing tube; a guide strip hole is provided in the guide member that passes through its front and rear ends, and the two ends of the guide rod are located in the guide strip hole; when the caster is in an open state, the two ends of the guide rod are correspondingly embedded in the two locking grooves.

[0016] As a specific embodiment, a positioning pin is provided on the inner side edge of each of the fixing parts; a snap-fitting positioning groove cooperating with the positioning pin is provided on the outer side edge of each of the positioning blocks; a positioning bead is provided on both sides of each of the snap-fitting positioning grooves, and a gap is left between the two positioning beads for the positioning pin to pass through; the positioning block and the positioning pin can be engaged or separated by pulling or pushing the push handle.

[0017] The beneficial effects of the present invention are:

[0018] (I) The structure of the present invention is simple and reasonable, and it is easy to use. The push handle can be easily stored at the bottom of the support plate, is not easy to be damaged, and can reduce the volume of the flatbed cart, which is convenient for storage and transportation. When in use, the two ends of the push part and the two fixed parts are respectively installed on two guide rails. When it is necessary to pull the flatbed cart, it is only necessary to pull the push handle outward to make the push part detach from the guide rail and extend out of the support plate, and the positioning block limits the fixed part. In this way, the push part can be hinged with the fixed part so that the push part can be turned up and down outside the support plate, which is convenient for people to adjust the angle according to their usage habits.

[0019] (ii) The present invention can further reduce the size of the flatbed cart by providing foldable casters, which is more convenient for storage and transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The overall structure of the present invention in a folded state is shown in FIG. Figure 1 ;

[0021] Figure 2 The overall structure of the present invention in a folded state is shown in FIG. Figure 2 ;

[0022] Figure 3 It is a schematic diagram of the local structure of the present invention Figure 1 ;

[0023] Figure 4 It is a schematic diagram of the local structure of the present invention Figure 2 ;

[0024] Figure 5 It is a schematic diagram of the local structure of the present invention Figure 3 ;

[0025] Figure 6 It is a schematic diagram of the principle of the caster fixing seat and the latch of the present invention when in use;

[0026] Figure 7 It is a structural schematic diagram of the caster fixing seat of the present invention;

[0027] Figure 8 is a schematic structural diagram of the guide locking assembly of the present invention;

[0028] Fig. 9 This is a schematic diagram of the overall structure of the present invention when it is in an open state. Figure 1 ;

[0029] Fig.10 This is a schematic diagram of the overall structure of the present invention when it is in an open state. Figure 2 .

[0030] Reference numerals:

[0031] 1. Support plate; 101. Front positioning frame bar; 1011. Positioning bar-shaped hole; 102. Left positioning frame bar; 103. Right positioning frame bar; 104. Rear positioning frame bar; 2. Pusher; 21. Pushing part; 211. Insert block; 22. Fixing part; 221. Slot; 222. Positioning pin; 23. Limit groove; 3. Guide rail; 31. Connecting part; 32. Limiting part; 4. Positioning block; 41. Step; 42. Engaging positioning groove; 43. Positioning bead; 5. Fixed pipe; 51. First bar-shaped hole; 52. Second bar-shaped hole; 6. Sliding pipe; 7. Caster fixing seat; 71. Arc track; 72. Opening positioning groove; 73. Folding positioning groove; 74. Inner fixing seat; 741. First arc surface; 742. Locking block; 743. Locking groove; 75. Outer fixing seat; 751. Second arc surface; 752. Bayonet; 8. Guide locking assembly; 81. Guide rod; 82. Guide part; 821. Guide bar-shaped hole; 9. Plug pin; 10. Caster; 11. Spring. Detailed implementation manners

[0032] The following further elaborates on the invention in conjunction with the accompanying drawings and specific embodiments. The following description is merely exemplary and does not limit the protection scope of the invention.

[0033] As Figure 1-Figure 10 shown, a flat trolley includes a support plate 1 and a pusher 2; on both sides of the bottom of the support plate 1, two guide rails 3 are symmetrically arranged respectively; the pusher 2 includes a pushing part 21 and two fixing parts 22 respectively hinged at both ends of the pushing part 21; both ends of the pushing part 21 and the two fixing parts 22 are respectively slidably mounted on the two guide rails 3 in a front-back manner; on the bottom of the support plate 1, two positioning blocks 4 are also provided respectively for limiting the two fixing parts 22; when the pushing part 21 is pulled outwards until the positioning block 4 limits the fixing part 22, the pushing part 21 extends outside the support plate 1. Preferably, the pushing part 21 is in the shape of "冖". The structure of the present invention is simple and reasonable, easy to use, the pusher 2 can be conveniently stored at the bottom of the support plate 1, not easily damaged, and can reduce the volume of the flat trolley, which is beneficial to storage and transportation. When in use, both ends of the pushing part 21 and the two fixing parts 22 are respectively mounted on the two guide rails 3. When it is necessary to pull the flat trolley, only need to pull the pusher 2 outwards, so that the pushing part 21 disengages from the guide rail 3 and extends outside the support plate 1, and the positioning block 4 limits the fixing part 22. In this way, the pushing part 21 can be turned up and down outside the support plate 1 by using the hinge between the pushing part 21 and the fixing part 22, which is convenient for people to adjust the angle according to their usage habits.

[0034] As Figure 3As shown, each guide rail 3 includes a connecting portion 31 for connecting with the support plate 1 and a "T"-shaped limiting portion 32 arranged at the lower end of the connecting portion 31; and a "T"-shaped limiting groove 23 for correspondingly sleeved on the limiting portion 32 is respectively provided on both ends of the pushing portion 21 and the two fixing portions 22. The above arrangement enables the push handle 2 to slide stably on the guide rail 3 to prevent the push handle 2 from loosening from the guide rail 3. Of course, the shape of the limiting portion 32 and the limiting groove 23 can also be set to other shapes, for example, a convex portion can be set on the limiting portion 32 and the limiting groove 23, so as to further increase the stability of the push handle 2 when sliding.

[0035] like Figure 3 As shown, an insert block 211 is provided at each end of the push portion 21; a slot 221 that matches the insert block 211 is provided at the front end of each of the two fixing portions 22; corresponding plug holes are provided on both sides of the insert block 211 and the slot 221, and bolts are installed horizontally in the plug holes to hinge the insert block 211 and the fixing portion 22. The above arrangement allows the push portion 21 and the fixing portion 22 to be stably hinged, and the structure is stable. However, those skilled in the art should know that the push portion 21 and the fixing portion 22 can also be hinged by using hinges or other articulated parts.

[0036] like Figure 2 and Figure 3 As shown, the flatbed cart also includes at least two folding caster assemblies; two fixed tubes 5 extending forward and backward are symmetrically arranged at the bottom of the support plate 1, and a sliding tube 6 that can slide along the length direction of the fixed tube 5 is respectively arranged in the two fixed tubes 5; the folding caster assemblies are correspondingly installed on the two fixed tubes 5 and the two sliding tubes 6; two positioning blocks 4 are respectively installed at the front ends of the two sliding tubes 6, and the two positioning blocks 4 are respectively matched with the two folding caster assemblies and the push handle 2. In this embodiment, the folding caster assemblies are provided with four evenly distributed ones.

[0037] like Figure 5-Figure 7As shown, each caster folding assembly includes a caster fixing seat 7 rotatably mounted on a fixing tube 5, a caster 10 connected to one side of the caster fixing seat 7, and a latch 9 fixed to the outer wall of the sliding tube 6; a first strip hole 51 for the latch 9 to move forward and backward is provided on the fixing tube 5; an arc track 71 for guiding the caster fixing seat 7 is provided inside the caster fixing seat 7, and the latch 9 is inserted in the arc track 71; opening positioning grooves 72 and folding grooves 73 are respectively provided at both ends of the arc track 71. Positioning slot 73; when the push handle 2 is pulled outward, the push handle 2 drives the positioning block 4 to move forward, and synchronously drives the latch 9 to move from back to front along the arc track 71, and when the latch 9 is inserted into the open positioning slot 72, the caster 10 is changed from the folded state to the open state; when the push handle 2 is pushed inward, the push handle 2 drives the positioning block 4 to move backward, and synchronously drives the latch 9 to move from front to back along the arc track 71, and when the latch 9 is inserted into the folding positioning slot 73, the caster 10 is changed from the open state to the folded state. The above arrangement enables the caster 10 to be synchronously switched between the folded and opened states when the push handle 2 is pulled or pushed, for easy use, and this operation method is simple and quick. Preferably, as Figure 6 As shown, two symmetrically arranged latches 9 are provided, and two arc-shaped tracks 71, opening positioning grooves 72 and folding positioning grooves 73 are also provided respectively corresponding to the two latches 9, thereby improving the rotation stability of the caster fixing seat 7 and preventing the caster fixing seat 7 from being easily damaged.

[0038] like Figure 2 As shown, a front positioning frame strip 101 is also provided on the front side of the support plate 1 ; a positioning strip hole 1011 is provided on the front positioning frame strip 101 , the push handle 2 is matchedly inserted into the positioning strip hole 1011 , and the front positioning frame strip 101 is used to block the positioning block 4 .

[0039] like Figure 4 As shown, a step 41 is provided on both sides of the front end of each positioning block 4; the front end of the positioning block 4 can be inserted into the positioning bar hole 1011, and the positioning block 4 can be engaged with the front positioning frame strip 101 through the two steps 41. The above arrangement can conveniently block the positioning block 4 to prevent the push handle 2 from falling off the guide rail 3. When in use, after the push handle 2 drives the front end of the positioning block 41 to pass through the positioning bar hole 1011, the two steps 41 also correspondingly press against the front positioning frame strip 101, so that the push handle 2 can complete the locking.

[0040] like Figure 5-Figure 7As shown, the caster fixing seat 7 includes an inner fixing seat 74 and an outer fixing seat 75; the inner fixing seat 74 is sleeved on the outer wall of the fixing tube 5; a first arcuate surface 741 extending from the back to the front is provided at the front end of the inner fixing seat 74, and a folding positioning groove 73 is connected to the rear end of the first arcuate surface 741; the outer fixing seat 75 is sleeved on the inner fixing seat 74 and the fixing tube 5 in a matching manner, and the caster 10 is connected to one side of the outer fixing seat 75, specifically, the outer fixing seat 75 and the inner fixing seat 74 are mutually engaged through a clamping block and a clamping groove for synchronous movement; a second arcuate surface 751 matching with the first arcuate surface 741 and extending from the back to the front is provided inside the outer fixing seat 75, and an opening positioning groove 72 is connected to the front end of the second arcuate surface 751; an arc track 71 is formed between the first arcuate surface 741 and the second arcuate surface 751. The above arrangement can facilitate the production and disassembly of the caster fixing seat 7 and the latch 9, and can also make the latch 9 convenient to move.

[0041] like Figure 4 , Figure 5 and Figure 8 As shown, each of the caster folding components also includes a guide locking component 8 arranged behind the caster fixing seat 7 and matched with the caster fixing seat 7; a locking block 742 is respectively arranged on the outer walls of both sides of the inner fixing seat 74, and a locking groove 743 with a rear end opening is respectively arranged on each locking block 742; the guide locking component 8 includes a guide rod 81 installed on the sliding tube 6 and a guide member 82 fixedly sleeved on the fixing tube 5; the two ends of the guide rod 81 are respectively passed through the outside of the sliding tube 6, and the fixing tube 5 is provided with a second strip hole 52 for the two ends of the guide rod 81 to move forward and backward; a guide strip hole 821 is provided in the guide member 82 that passes through the front and rear ends thereof, and the two ends of the guide rod 81 are located in the guide strip hole 821; when the caster 10 is in the open state, the two ends of the guide rod 81 are correspondingly embedded in the two locking grooves 743. By providing the guide locking component 8, the caster 10 can be conveniently maintained in the open state to prevent the caster 10 from loosening.

[0042] Preferably, in order to allow the guide rod 81 to be more smoothly inserted into the locking groove 743, the side surface of the guide rod 81 facing the locking groove 743 is an outwardly convex arc surface, that is, the guide rod 81 is a D-shaped rod.

[0043] like Figure 5 As shown, in order to facilitate the connection between the inner fixing seat 74 and the outer fixing seat 75, a bayonet 752 cooperating with the locking block 742 is provided at the lower end of the outer fixing seat 75. The bayonet 752 is engaged with the locking block 742 to improve the stability between the inner fixing seat 74 and the outer fixing seat 75.

[0044] like Figure 2 and Figure 4As shown, a positioning pin 222 is provided on the inner side of each fixing portion 22; a snap-fitting positioning groove 42 cooperating with the positioning pin 222 is provided on the outer side of each positioning block 4; a positioning bead 43 is provided on both sides of each snap-fitting positioning groove 42, and a gap is left between the two positioning beads 43 for the positioning pin 222 to pass through; the positioning block 4 and the positioning pin 222 can be locked or separated by pulling or pushing the push handle 2. The above arrangement can facilitate the fixing portion 22 to drive the positioning block 4 to move, and this arrangement can facilitate the locking or separation of the positioning block 4 and the positioning pin 222; at the same time, the arrangement of the two positioning beads 43 can limit the positioning pin 222 to prevent it from detaching. Since the positioning bead 43 is a prior art, it will not be described in detail here.

[0045] In this embodiment, if Figure 2 As shown, a left positioning frame bar 102, a right positioning frame bar 103 and a rear positioning frame bar 104 are respectively arranged on the left side, the right side and the rear side of the support plate 1; the front positioning frame bar 101, the left positioning frame bar 102, the right positioning frame bar 103 and the rear positioning frame bar 104 are sequentially connected to form a structural reinforcement frame. The above arrangement can strengthen the structure of the support plate 1 and make it more durable.

[0046] like Figure 4 and Figure 5 As shown, a spring 11 sleeved on the fixing tube 5 is also installed at the front end of the outer fixing seat 75, one end of the spring 11 is pressed against a fixing piece fixed on the fixing tube 5, and the other end is pressed against the outer fixing seat 75. In this embodiment, two springs 11 are provided, and the two springs 11 are respectively installed at the front ends of the two outer fixing seats 75 near the two positioning blocks 4. By providing the spring 11, the caster 10 can use the spring 11 to press against the caster fixing seat 7 when in use, and use the stretching force of the spring 11 to make the caster fixing seat 7 more stable, thereby improving the stability of the caster 10. At the same time, the spring 11 can also play a partial shock-absorbing role to a certain extent.

[0047] Combination Fig. 9 and Fig.10 , the use principle of the present invention is introduced below to facilitate understanding of the present invention:

[0048] First, the flatbed cart is Figure 1 and Figure 2When it is necessary to open, pull the push part 21 to make the push part 21 pass out of the positioning strip hole 1011; when the positioning pins 222 on the two fixing parts 22 move to the preset position and pass through the two positioning beads 43 and then are inserted into the two engaging positioning grooves 42, the two positioning blocks 4 then move forward following the fixing parts 22; when the two positioning blocks 4 move, the two sliding tubes 6 and the latch pins 9 and the guide rods 81 on the sliding tubes 6 move forward, and the latch pins 9 disengage from the folding positioning grooves 73 and move forward along the arc track 71. Since the latch pins 9 can only move in the front-rear direction, when they move, they will cause the caster fixing seat 7 to be moved by the water. The horizontal state is changed to the vertical state, and the caster 10 is synchronously driven to change from the folded state to the opened state; when the latch 9 is inserted into the opening positioning groove 72, the caster 10 is opened, and one side of the guide rod 81 just passes through the guide bar hole 821 and is inserted into the locking groove 743. At the same time, the front end of the positioning block 4 is just inserted into the positioning bar hole 1011 and uses the step 41 to press against the front positioning frame bar 101, and the pushing part 21 just breaks away from the guide rail 3 and extends out of the support plate 1, and people can freely flip the pushing part 21 to use it; the opening of the flatbed cart is completed through the above steps, and the opening state of the flatbed cart is as shown in FIG. Fig. 9 and Fig.10 shown.

[0049] When folding is required, the pushing portion 21 is turned over to make it level with the fixing portion 22, and then the pushing handle 2 is pushed backward into the positioning strip hole 1011. During the movement, the positioning pin 222 passes through the two positioning beads 43 and separates from the engaging positioning groove 42; when the front end of the pushing portion 21 enters the positioning strip hole 1011, it contacts the two positioning blocks 4 and pushes the two positioning blocks 4 to move backward, driving the two sliding tubes 6 and the latch pin 9 and the guide rod 81 on the sliding tube 6 to move backward, the latch pin 9 disengages from the opening positioning groove 72 and the guide rod 81 is disengaged. After the locking positioning groove 42 is released, it moves along the guide strip hole 821, and the latch 9 moves backward along the arc track 71, prompting the caster fixing seat 7 to change from the vertical state to the horizontal state, and synchronously driving the caster 10 to change from the open state to the folded state; when the latch 9 is inserted into the folding positioning groove 73, the folding of the caster 10 is completed, the positioning block 4 is separated from the front positioning frame strip 101, and the front end of the pushing part 21 is also correspondingly embedded in the positioning strip hole 1011; the folding of the flatbed cart is completed through the above steps, and the folded state of the flatbed cart is as shown in FIG. Figure 1 and Figure 2 shown.

[0050] In summary, the present invention can greatly reduce the volume of the flatbed cart by providing a handle that can be stored at the bottom of the support plate 1 and providing foldable casters 10, which is convenient for storage and transportation; at the same time, the operation method of the present invention is very simple and convenient, which is easy to use.

[0051] The present invention is not limited to the above-mentioned embodiments. If various changes or modifications to the present invention do not depart from the spirit and scope of the present invention, and if these changes and modifications fall within the scope of the claims and equivalent technologies of the present invention, the present invention is also intended to include these changes and modifications.

Claims

1. A flatbed cart, comprising a support plate and a handle, characterized in that: A guide rail is symmetrically arranged on both sides of the bottom of the support plate; the push handle includes a pushing portion and two fixing portions respectively hinged at both ends of the pushing portion; the two ends of the pushing portion and the two fixing portions are respectively slidably mounted on the two guide rails; two positioning blocks are also arranged at the bottom of the support plate for limiting the positions of the two fixing portions; when the pushing portion is pulled outward until the positioning block limits the position of the fixing portion, the pushing portion extends out of the support plate; The flatbed cart also includes at least two folding caster assemblies; two fixed tubes extending forward and backward are symmetrically arranged at the bottom of the support plate, and a sliding tube that can slide along the length direction of the fixed tube is respectively arranged in the two fixed tubes; the folding caster assembly is correspondingly installed on the two fixed tubes and the two sliding tubes; the two positioning blocks are respectively installed at the front ends of the two sliding tubes, and the two positioning blocks are respectively matched with the two folding caster assemblies and the push handle; Each of the caster folding components includes a caster fixing seat rotatably mounted on the fixing tube, a caster connected to one side of the caster fixing seat and a latch fixed on the outer wall of the sliding tube; a first strip hole is provided on the fixing tube for the latch to move forward and backward; an arc track for guiding the caster fixing seat is provided inside the caster fixing seat, and the latch is inserted in the arc track; an opening positioning groove and a folding positioning groove are respectively provided at both ends of the arc track; when the push handle is pulled outward, the push handle drives the positioning block to move forward, and simultaneously drives the latch to move along the arc track from back to front, and when the latch is embedded in the opening positioning groove, the caster is changed from a folded state to an opened state; when the push handle is pushed inward, the push handle drives the positioning block to move backward, and simultaneously drives the latch to move along the arc track from front to back, and when the latch is embedded in the folding positioning groove, the caster is changed from an opened state to a folded state.

2. The flatbed cart according to claim 1, characterized in that: Each of the guide rails includes a connecting portion for connecting to the support plate and a "T"-shaped limiting portion arranged at the lower end of the connecting portion; and "T"-shaped limiting grooves for correspondingly sleeved on the limiting portion are respectively provided on both ends of the pushing portion and the two fixing portions.

3. The flatbed cart according to claim 1, characterized in that: An insert block is respectively provided at both ends of the pushing part; a slot matching the insert block is respectively provided at the front end of the two fixing parts; corresponding sockets are respectively provided on both sides of the insert block and the slot, and bolts are horizontally installed in the sockets to hinge the insert block with the fixing part.

4. The flatbed cart according to claim 1, characterized in that: A front positioning frame strip is also provided on the front side of the support plate; a positioning strip-shaped hole is provided on the front positioning frame strip, the push handle is matchedly inserted into the positioning strip-shaped hole, and the front positioning frame strip is used to block the positioning block.

5. The flatbed cart according to claim 4, characterized in that: A step is respectively provided on both sides of the front end of each positioning block; the front end of the positioning block can be inserted into the positioning bar-shaped hole, and the positioning block can be engaged with the front positioning frame bar through the two steps.

6. The flatbed cart according to claim 1, characterized in that: The caster fixing seat includes an inner fixing seat and an outer fixing seat; the inner fixing seat is sleeved on the outer wall of the fixing tube; a first arcuate surface extending from back to front is provided at the front end of the inner fixing seat, and the folding positioning groove is connected to the rear end of the first arcuate surface; the outer fixing seat is cooperatively sleeved on the inner fixing seat and the fixing tube, and the caster is connected to one side of the outer fixing seat; a second arcuate surface matching the first arcuate surface and extending from back to front is provided inside the outer fixing seat, and the opening positioning groove is connected to the front end of the second arcuate surface; the arc track is formed between the first arcuate surface and the second arcuate surface.

7. The flatbed cart according to claim 6, characterized in that: Each of the caster folding components also includes a guide locking component arranged behind the caster fixing seat and cooperating with the caster fixing seat; a locking block is respectively arranged on the outer walls of both sides of the inner fixing seat, and a locking groove with a rear end opening is respectively arranged on each of the locking blocks; the guide locking component includes a guide rod installed on the sliding tube and a guide member fixedly mounted on the fixing tube; the two ends of the guide rod are respectively passed through the outside of the sliding tube, and a second strip hole for the two ends of the guide rod to move forward and backward is provided on the fixing tube; a guide strip hole is provided in the guide member that passes through its front and rear ends, and the two ends of the guide rod are located in the guide strip hole; when the caster is in the open state, the two ends of the guide rod are correspondingly embedded in the two locking grooves.

8. The flatbed cart according to claim 1, characterized in that: A positioning pin is provided on the inner side edge of each of the fixing parts; a snap-fitting positioning groove cooperating with the positioning pin is provided on the outer side edge of each of the positioning blocks; a positioning bead is provided on both sides of each of the snap-fitting positioning grooves, and a gap is left between the two positioning beads for the positioning pin to pass through; the positioning block and the positioning pin can be engaged or separated by pulling or pushing the push handle.

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