A caster folding structure for a flatbed cart

Abstract

The present invention discloses a caster folding structure of a flatbed cart, comprising a support plate; further comprising 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 arranged in the two fixed tubes; the caster folding assemblies are correspondingly mounted on the two fixed tubes and the two sliding tubes; each caster folding assembly comprises a caster fixing seat rotatably sleeved on the fixed 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 for the latch to move forward and backward is arranged on the fixed tube; an arc track for guiding the caster fixing seat is arranged 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 arranged at both ends of the arc track. The present invention can effectively reduce the volume of the cart by arranging foldable casters, 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 caster folding structure of a flatbed cart. Background Art

[0002] The folding caster structure of the flatbed cart is a small material transport device that is widely used in production and life. It is low-cost, simple to maintain, easy to operate, and light in weight. 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 and casters connected to the support plate. However, the existing casters are generally fixed to the bottom of the support plate and cannot be folded, which results in a larger 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 caster folding structure for a flatbed cart, which has a simple and reasonable structure and is easy to use. By providing foldable casters, the volume of the flatbed cart can be effectively reduced, which is conducive to storage and transportation. At the same time, this folding structure is stable and effective, and is very easy to operate.

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

[0006] The folding structure of a flatbed cart comprises a support plate; and 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 arranged in the two fixed tubes; the caster folding assembly is correspondingly installed on the two fixed tubes and the two sliding tubes; each of the caster folding assemblies comprises 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 for the latch to move forward and backward is provided on the fixing tube; 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; opening positioning grooves and folding positioning grooves are respectively provided at both ends of the arc track; the caster can be switched between a folded state and an opened state by cooperating with the arc track during the forward and backward movement of the latch.

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

[0008] As a specific embodiment, 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 curved 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 curved 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 curved surface matching the first curved 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 curved surface; the curved track is formed between the first curved surface and the second curved surface.

[0009] 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.

[0010] Furthermore, the side surface of the guide rod facing the locking groove is an outwardly convex arc surface.

[0011] Furthermore, a spring sleeved on the fixing tube is installed at the front end of the outer fixing seat; one end of the spring presses against a fixing piece fixed on the fixing tube, and the other end presses against the outer fixing seat.

[0012] As a specific embodiment, a positioning block is installed at the front end of each sliding tube; a front positioning frame strip is also arranged on the front side of the support plate; a positioning strip hole is arranged on the front positioning frame strip, and the front positioning frame strip is used to block the positioning block.

[0013] Furthermore, a left positioning frame bar, a right positioning frame bar and a rear positioning frame bar are respectively arranged on the left side, right side and rear side of the support plate; the front positioning frame bar, the left positioning frame bar, the right positioning frame bar and the rear positioning frame bar are connected in sequence to form a structural reinforcement frame.

[0014] 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.

[0015] As a specific embodiment, the caster folding assemblies are provided with four and the four caster folding assemblies are evenly arranged.

[0016] As a specific embodiment, the latches are provided with two symmetrically arranged ones, and the arc track, the opening positioning groove and the folding positioning groove are also provided with two corresponding ones to the two latches.

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

[0018] The invention has a simple and reasonable structure and is easy to use. By providing foldable casters, the volume of the flatbed cart can be effectively reduced, which is convenient for storage and transportation. At the same time, the folding structure is stable and effective, and the operation is very convenient. When in use, the sliding tube moves forward and backward, synchronously driving the latch to move forward and backward, and prompting the casters to switch between the folded state and the opened state, and the process is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention when it is in a folded state. Figure 1 ;

[0020] Figure 2 This is a schematic diagram of the overall structure of the present invention when it is in a folded state. Figure 2 ;

[0021] Figure 3 It is a schematic diagram of the local structure of the present invention Figure 1 ;

[0022] Figure 4 It is a schematic diagram of the local structure of the present invention Figure 2 ;

[0023] Figure 5 It is a schematic diagram of the local structure of the present invention Figure 3 ;

[0024] 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;

[0025] Figure 7 It is a structural schematic diagram of the caster fixing seat of the present invention;

[0026] Figure 8 is a schematic structural diagram of the guide locking assembly of the present invention;

[0027] Fig. 9 This is a schematic diagram of the overall structure of the present invention when it is in an open state. Figure 1 ;

[0028] Fig.10 This is a schematic diagram of the overall structure of the present invention when it is in an open state. Figure 2 .

[0029] Reference numerals:

[0030] 1. Support plate; 101. Front positioning frame strip; 1011. Positioning strip hole; 102. Left positioning frame strip; 103. Right positioning frame strip; 104. Rear positioning frame strip; 2. Push handle; 21. Pushing part; 211. Insert block; 22. Fixing part; 221. Slot; 222. Positioning pin; 23. Limiting groove; 3. Guide rail; 31. Connecting part; 32. Limiting part; 4. Positioning block; 41. Step; 42. Engagement positioning groove; 43. Positioning bead; 5. Fixing tube; 51. A strip hole; 52, a second strip hole; 6, a sliding tube; 7, a caster fixing seat; 71, an arc track; 72, an open positioning groove; 73, a folded positioning groove; 74, an inner fixing seat; 741, a first arc surface; 742, a locking block; 743, a locking groove; 75, an outer fixing seat; 751, a second arc surface; 752, a bayonet; 8, a guide locking assembly; 81, a guide rod; 82, a guide piece; 821, a guide strip hole; 9, a latch; 10, a caster; 11, a spring. DETAILED DESCRIPTION

[0031] The invention is further described below in conjunction with the accompanying drawings and specific embodiments. The following description is only exemplary and does not limit the protection scope of the invention.

[0032] like Figure 1-Figure 10As shown, a caster folding structure of a flatbed cart includes a support plate 1; and at least two caster folding 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 caster folding assemblies are correspondingly installed on the two fixed tubes 5 and the two sliding tubes 6; each caster folding assembly includes a caster fixing seat 7 rotatably sleeved on the fixed tube 5, a caster 10 connected to one side of the caster fixing seat 7 and a caster 10 fixed to the sliding tube 6 The bolt 9 is provided on the outer wall of the caster 10; the fixing tube 5 is provided with a first strip hole 51 for the bolt 9 to move forward and backward; the caster fixing seat 7 is provided with an arc track 71 for guiding the caster fixing seat 7, and the bolt 9 is inserted in the arc track 71; the two ends of the arc track 71 are provided with an opening positioning groove 72 and a folding positioning groove 73; the caster 10 can be switched between the folding state and the opening state by the bolt 9 cooperating with the arc track 71 during the forward and backward movement. Specifically, when the sliding tube 6 moves forward and backward, it will synchronously drive the bolt 9 to move forward and backward. In this embodiment, the bolt 9 is provided with two symmetrically arranged bolts, and the arc track 71, the opening positioning groove 72 and the folding positioning groove 73 are also provided with two bolts corresponding to the two bolts 9, so that the rotation stability of the caster fixing seat 7 can be improved, and the caster fixing seat 7 is not easy to be damaged. The present invention has a simple and reasonable structure and is easy to use. By providing the foldable casters 10, the volume of the flatbed cart can be effectively reduced, which is convenient for storage and transportation. At the same time, the folding structure is stable and effective, and is very easy to operate.

[0033] like Figure 5-Figure 7 As 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.

[0034] like Figure 5As 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.

[0035] 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.

[0036] 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.

[0037] 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 member fixed on the fixing tube 5, and the other end is pressed against the outer fixing seat 75. 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.

[0038] like Figure 1-Figure 4 As shown, a positioning block 4 is installed at the front end of each sliding tube 6; a front positioning frame strip 101 is also provided at the front side of the support plate 1; a positioning bar-shaped hole 1011 is provided on the front positioning frame strip 101, and the front positioning frame strip 101 is used to block the positioning block 4. Through the above arrangement, the positioning block 4 can be used to conveniently drive the sliding tube 6 to move forward and backward, and synchronously drive the latch 9 to move forward and backward, and the front positioning frame strip 101 can be used to prevent the sliding tube 6 from exceeding the preset stroke and damaging the latch 9.

[0039] As Figure 1 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, right side and 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 strengthening frame. Through the above settings, the structure of the support plate 1 can be strengthened to make it more durable.

[0040] As Figure 4 shown, on both sides of the front end of each positioning block 4, a step 41 is respectively provided; the front end of the positioning block 4 can be inserted into the positioning strip-shaped hole 1011, and the positioning block 4 can be engaged with the front positioning frame bar 101 through two steps 41. Through the above settings, it is convenient to tightly block the positioning block 4. During use, after the front end of the positioning block 41 penetrates into the positioning strip-shaped hole 1011, the two steps 41 also correspondingly abut against the front positioning frame bar 101, thus completing the card position.

[0041] In this embodiment, four caster folding assemblies are provided and the four caster folding assemblies are evenly arranged.

[0042] In this embodiment, two springs 11 are provided, and the two springs 11 are respectively installed at the front ends of two outer fixing seats 75 close to the two positioning blocks 4.

[0043] As Figure 1-Figure 3 shown, in order to facilitate driving the two positioning blocks 4 to move, a push handle 2 is further arranged on the support plate 1; guide rails 3 are symmetrically arranged on both sides of the bottom of the support plate 1; the push handle 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 installed on the two guide rails 3 in a front-back manner; the two positioning blocks 4 are used to limit 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". During use, both ends of the pushing part 21 and the two fixing parts 22 are installed on the two guide rails 3. When it is necessary to pull the flat cart, only need to pull the push handle 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, so that 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.

[0044] 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.

[0045] 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.

[0046] like Figure 1 and Figure 4 As 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.

[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 caster folding structure 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 beneficial for storage and transportation; at the same time, the operation method of the present invention is very simple and convenient, which is conducive 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 folding caster structure of a flatbed cart, comprising a support plate, characterized in that: The invention also comprises at least two folding caster assemblies; two fixing tubes extending forward and backward are symmetrically arranged at the bottom of the support plate, and a sliding tube which can slide along the length direction of the fixing tube is respectively arranged in the two fixing tubes; the caster folding assembly is correspondingly mounted on the two fixing tubes and the two sliding tubes; each of the caster folding assemblies comprises a caster fixing seat rotatably sleeved 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 for the latch to move forward and backward is arranged on the fixing tube; an arc track for guiding the caster fixing seat is arranged inside the caster fixing seat, and the latch is inserted in the arc track; opening positioning grooves and folding positioning grooves are respectively arranged at both ends of the arc track; the caster can be switched between a folded state and an opened state by cooperating with the arc track during the forward and backward movement of the latch; The caster fixing seat comprises 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 the back to the 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 sleeved on the inner fixing seat and the fixing tube in a matching manner, and the caster is connected to one side of the outer fixing seat; a second arcuate surface matching with the first arcuate surface and extending from the back to the 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; A push handle is also provided on the support plate; the push handle includes a pushing part and two fixed parts respectively hinged at both ends of the pushing part; a positioning pin is provided on the inner side edge of each of the fixed parts; a positioning block is also installed on the front end of each of the sliding tubes; 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 also 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 locked or separated by pulling or pushing the push handle; when the positioning pins on the two fixed parts move to the preset position and pass through the two positioning beads and are inserted into the two snap-fitting positioning grooves, the two positioning blocks then move forward following the fixed part.

2. The caster folding structure of the flatbed cart according to claim 1, 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.

3. The caster folding structure of the flatbed cart according to claim 2, characterized in that: The side surface of the guide rod facing the locking groove is an outwardly convex arc surface.

4. The caster folding structure of the flatbed cart according to claim 1, characterized in that: A spring sleeved on the fixing tube is also installed at the front end of the outer fixing seat; one end of the spring presses against a fixing piece fixed on the fixing tube, and the other end presses against the outer fixing seat.

5. The caster folding structure of a flatbed cart according to claim 1, characterized in that: A front positioning frame strip is also arranged on the front side of the support plate; a positioning strip-shaped hole is arranged on the front positioning frame strip, and the front positioning frame strip is used to block the positioning block.

6. The caster folding structure of the flatbed cart according to claim 5, characterized in that: A left positioning frame bar, a right positioning frame bar and a rear positioning frame bar are respectively arranged on the left side, the right side and the rear side of the support plate; the front positioning frame bar, the left positioning frame bar, the right positioning frame bar and the rear positioning frame bar are sequentially connected to form a structural reinforcement frame.

7. The caster folding structure of the flatbed cart according to claim 5, 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.

8. The caster folding structure of a flatbed cart according to claim 1, characterized in that: The caster folding assemblies are provided with four and the four caster folding assemblies are evenly arranged.

9. The caster folding structure of a flatbed cart according to claim 1, characterized in that: The latches are provided with two symmetrically arranged ones, and the arc-shaped track, the opening positioning groove and the folding positioning groove are also provided with two corresponding ones to the two latches.

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