A flatbed truck with foldable caster unit

Abstract

The present invention discloses a flatbed cart with a foldable caster unit, comprising a load-bearing plate, a load-bearing support frame, and a caster unit, and further comprising a caster unit rotation drive device, wherein the caster unit rotation drive device comprises an operating handle, a connecting rod, a front linkage mechanism, and a rear linkage mechanism, wherein the operating handle is pivotally connected to the load-bearing plate and can rotate around the operating handle pivot axis, and when the operating handle is rotated from a first position to a second position, the operating handle can link the front linkage mechanism and the rear linkage mechanism to respectively drive the front caster unit and the rear caster unit to rotate from a folded storage position to an unfolded rolling position through the connecting rod, and the front and rear caster units are both provided with a reset device, and when the operating handle is rotated from the second position to the first position, the front and rear caster units can rotate from the unfolded rolling position to the folded storage position under the action of the reset device. The beneficial effect of the present invention is that the folding and unfolding operations of the caster unit are simple, convenient, and fast, and the space occupied is reduced, making it convenient to carry and store.

Description

Technical Field

[0001] The present invention belongs to the technical field of small-sized flat transport equipment, and more specifically, relates to a flatbed vehicle with a foldable caster unit. Background Art

[0002] Flatbed trucks are a common means of transport, primarily used in shopping malls and supermarkets to move goods between shelves and warehouses, and for the storage and transportation of consumer purchases. Different scenarios require different flatbed trucks, but existing flatbed trucks lack the functionality to handle multiple scenarios. Furthermore, most flatbed trucks lack foldable casters, taking up significant space and making storage difficult, which increases transportation costs.

[0003] At present, there are flatbed trucks on the market that are equipped with push handles and foldable caster units. The opening or folding of the push handles are linked to the synchronous opening or folding of the caster units. For this type of flatbed truck, when the push handle is opened to a 90-degree vertical position relative to the load-bearing plate, the caster unit is synchronously opened to a fully open state. Therefore, in order to ensure synchronization with the caster unit, the push handle of this type of flatbed truck cannot be opened to an angle of more than 90 degrees relative to the load-bearing plate, and it cannot be used as a flatbed trailer, and its working mode is restricted. Summary of the Invention

[0004] The purpose of the present invention is to solve at least one of the above-mentioned technical problems, and to provide a flatbed truck with foldable caster units, which has simple and quick operations for folding and storing or unfolding and rolling, stable performance, and can cope with various scenarios.

[0005] The present invention is achieved through the following technical solutions.

[0006] The present invention provides a flatbed cart with a foldable caster unit, comprising a load-bearing plate, a load-bearing support frame and a caster unit, wherein the load-bearing support frame is arranged at the bottom of the load-bearing plate, the caster unit is mounted on the load-bearing support frame and can rotate around the corresponding caster unit pivot axis between a folded storage position and an unfolded rolling position, the caster unit comprises a front caster unit and a rear caster unit, and also comprises a caster unit rotation drive device, the caster unit rotation drive device comprises an operating handle, a connecting rod, a front linkage mechanism and a rear linkage mechanism, the operating handle is pivotally connected to the load-bearing plate and can rotate around the operating handle pivot axis, The connecting rod is connected to the operating handle, the front linkage mechanism is connected to the connecting rod and the front caster unit, and the rear linkage mechanism is connected to the connecting rod and the rear caster unit. When the operating handle is rotated from the first position to the second position, the operating handle can link the front linkage mechanism and the rear linkage mechanism through the connecting rod to respectively drive the front caster unit and the rear caster unit to rotate from the folded storage position to the unfolded rolling position. The front and rear caster units are both provided with a reset device. When the operating handle is rotated from the second position to the first position, the front and rear caster units can rotate from the unfolded rolling position to the folded storage position under the action of the reset device.

[0007] In the above technical solution, when it is necessary to use a flatbed cart with a foldable caster unit to transport goods, the user only needs to press the load-bearing plate with one hand and use the other hand to rotate the operating handle from the first position to the second position to link the front linkage mechanism and the rear linkage mechanism to drive the caster unit to open from the folded storage position to the unfolded rolling position, so that the flatbed cart with the foldable caster unit is converted to a working state, and the operation is simple, convenient and fast; when it is necessary to carry or store the flatbed cart with a foldable caster unit, the user only needs to press the load-bearing plate with one hand and use the other hand to rotate the operating handle from the second position to the first position to link the front linkage mechanism and the rear linkage mechanism to cancel the action on the caster unit. Under the action of the resetting device, the caster unit rotates from the unfolded rolling position to the folded storage position, so that the flatbed cart with the foldable caster unit is converted to a non-working state, reducing the occupied space and facilitating carrying and storage.

[0008] Preferably, a push handle is provided on the upper surface of the load-bearing plate, and the push handle includes two vertical rods, the bottom ends of the two vertical rods are pivotally connected to a fixing seat, the fixing seat is mounted on the load-bearing support frame and fixed at a position behind the rear caster unit, the push handle can rotate around the push handle pivot axis, a reinforcing rod is connected between the two fixing seats, and the reinforcing rod is provided with a locking mechanism capable of locking the push handle from rotating. In this way, by providing a push handle, and the push handle can rotate relative to the load-bearing plate without affecting the rotation of the caster unit, the present invention can have three working modes, specifically: a platform mode in which the push handle is attached to the upper surface of the load-bearing plate, a platform pushing mode in which the push handle is perpendicular to the load-bearing plate at 90 degrees, and a platform towing mode in which the push handle is rotated more than 90 degrees but less than 180 degrees relative to the load-bearing plate, which is more flexible to use.

[0009] Preferably, the front linkage mechanism includes a front drive tube, a front support arm and a front fixed seat, the front drive tube is rotatably connected to the connecting rod, one end of the front support arm is connected and fixed to the front drive tube, the other end of the front support arm is pivotally connected to the front fixed seat, and the front fixed seat is connected and fixed to the load-bearing plate, and the front drive tube is configured so that when the operating handle is rotated from the first position to the second position, the end of the front drive tube can contact the inner side of the front caster unit to drive the front caster unit to rotate and open to the unfolded rolling position. In this way, when the operating handle is rotated from the first position to the second position, the operating handle will link the connecting rod action to change the position of the front drive tube, so that the end of the front drive tube contacts the inner side of the front caster unit, forcing the front caster unit to rotate and open to the unfolded rolling position.

[0010] Preferably, the rear linkage mechanism includes a rear drive tube, a rear support arm, and a rear fixed seat, the rear drive tube is rotatably connected to the connecting rod, one end of the rear support arm is connected and fixed to the rear drive tube, the other end of the rear support arm is pivotally connected to the rear fixed seat, and the rear fixed seat is connected and fixed to the load-bearing plate, and the rear drive tube is configured so that when the operating handle is rotated from the first position to the second position, the end of the rear drive tube can contact the inner side of the rear caster unit to drive the rear caster unit to rotate and open to the unfolded rolling position. In this way, when the operating handle is rotated from the first position to the second position, the operating handle will link the connecting rod action to change the position of the rear drive tube, so that the end of the rear drive tube contacts the inner side of the rear caster unit, forcing the rear caster unit to rotate and open to the unfolded rolling position.

[0011] Preferably, the operating handle is provided on the lower surface of the load-bearing plate, and the operating handle is provided with a lug, which is connected to a sliding sleeve. The sliding sleeve is mounted on a connecting rod and can slide along the connecting rod. The front and rear ends of the connecting rod are rotatably connected to the front drive tube and the rear drive tube, respectively. The lug is configured to drive the connecting rod away from or closer to the load-bearing plate when the operating handle is rotated between a first position and a second position. In this way, the sliding sleeve provided on the lug is a certain distance away from the pivot axis of the operating handle. When the operating handle is rotated from the first position to the second position, the distance between the sliding sleeve and the load-bearing plate changes, thereby driving the distance between the connecting rod and the load-bearing plate to change. The connecting rod links the front drive tube and the rear drive tube to move against the inner side of the caster unit, forcing the caster unit to open to the deployed rolling position, thereby achieving the opening of the caster unit.

[0012] Preferably, the operating handle includes a U-shaped handle body, the handle body includes two side arms of an integral structure and a grip arranged between the two side arms to connect one end of the two side arms, a rotating shaft and a positioning shaft are further provided between the two side arms, the rotating shaft is provided at the end of the two side arms opposite to the grip, and two mounting platforms for placing the rotating shafts are symmetrically provided at the position corresponding to the rotating shaft on the lower surface of the load-bearing plate, a semi-circular groove is provided on the top surface of the mounting platform, the rotating shaft is placed in the semi-circular groove and is fixed with a pressure plate provided with a semi-circular groove on the back cover, and two groups of positioning clips are provided on the lower surface of the load-bearing plate, and the two groups of positioning clips are symmetrically fixed to the position corresponding to the positioning shaft on the lower surface of the load-bearing plate with the rotating shaft as the symmetry axis, and the positioning shaft can be respectively clamped into the two groups of positioning clips when the operating handle is in the first position and the second position to fix the operating handle.

[0013] Preferably, the operating handle is provided on the upper surface of the load-bearing plate, and the operating handle is provided with a first connecting shaft and a second connecting shaft at positions on both sides of the operating handle pivot axis, respectively. The connecting rod includes a front connecting rod and a rear connecting rod, and the front connecting rod and the rear connecting rod are staggered in the axial direction of the operating handle pivot axis. One end of the front connecting rod is rotationally connected to the front drive tube, and the other end of the front connecting rod is rotationally connected to the first connecting shaft. One end of the rear connecting rod is rotationally connected to the rear drive tube, and the other end of the rear connecting rod is rotationally connected to the second connecting shaft. In this way, when the operating handle is rotated from the first position to the second position, the positions of the first connecting shaft and the second connecting shaft change simultaneously and respectively pull the front connecting rod and the rear connecting rod to operate. Moreover, the front connecting rod and the rear connecting rod will not interfere with each other during operation due to the staggered arrangement. The front connecting rod pulls the front drive tube to force the front caster to open to the unfolded rolling position, and the rear connecting rod pulls the rear drive tube to force the rear caster unit to open to the unfolded rolling position, thereby realizing the opening of the caster unit.

[0014] The cam is connected to the rear frame by a plurality of camshafts, the cam being connected to the rear frame by a plurality of camshafts, the cam being connected to the rear frame by a plurality of camshafts.

[0015] Preferably, the ends of the front drive tube and the rear drive tube are each provided with a locking plug, the locking plug being provided with a locking slot, and the front caster unit and the rear caster unit being provided with a locking post at a position corresponding to the locking slot, the locking post being configured to engage with the locking slot when the front caster unit and the rear caster unit are rotated to the deployed rolling position. In this way, after the locking post engages with the locking slot, the position of the front drive tube and the rear drive tube can be better maintained, preventing the caster unit from accidentally rotating and failing to maintain the deployed rolling position due to external forces such as vibration causing the position of the front drive tube and the rear drive tube to change during the rolling process.

[0016] Preferably, the caster unit includes a fixed sleeve, a rotating block, a caster frame, and a caster. The fixed sleeve has a recess at its lower portion, the rotating block is positioned within the recess, the fixed sleeve and the rotating block are both mounted on a load-bearing support frame, the fixed sleeve is connected and fixed to the load-bearing plate, the caster frame is connected and fixed to the rotating block, and the caster is rotatably mounted on the caster frame. The reset device is a torsion spring mounted on the load-bearing support frame, with its ends respectively abutting against the fixed sleeve and the rotating block to provide a force for the rotating block to rotate relative to the fixed sleeve. The clamping post is located on the inner side of the rotating block. This facilitates the processing and assembly of the caster unit.

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

[0018] (1) The caster unit can be folded to reduce space occupation and is convenient for carrying and storage;

[0019] (2) The folding and unfolding of the caster unit is simple, convenient and fast;

[0020] (3) The state conversion of the push handle will not affect the state of the caster unit, so that the present invention has three working modes, which can cope with various scenarios. They are the platform mode in which the push handle is stored on the upper surface of the load-bearing plate, the platform pushing mode in which the push handle is perpendicular to the load-bearing plate at 90 degrees, and the platform towing mode in which the push handle is rotated more than 90 degrees but less than 180 degrees relative to the load-bearing plate, which can meet the various transportation needs of users. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the decomposition structure of Example 1 of the present invention.

[0022] Figure 2 This is a schematic diagram of the bottom structure of Example 1 of the present invention.

[0023] Figure 3 This is a schematic diagram of the exploded structure of the caster unit rotation drive device of Example 1 of the present invention.

[0024] Figure 4 for Figure 3 Schematic diagram of the enlarged structure of part A.

[0025] Figure 5 This is a schematic diagram of the exploded structure of the caster unit according to Example 1 of the present invention.

[0026] Figure 6 This is a structural schematic diagram of the process of rotating the operating handle from the first position to the second position in Example 1 of the present invention with the load-bearing plate omitted.

[0027] Figure 7 This is a structural diagram of Example 1 of the present invention when the operating handle with the load-bearing plate omitted is located in the second position and the caster unit is located in the unfolded rolling position.

[0028] Figure 8 This is a structural diagram of the cooperation between the lock plug and the clamping column in Example 1 of the present invention.

[0029] Figure 9 This is a schematic diagram of the decomposition structure of Example 2 of the present invention.

[0030] Figure 10 This is a schematic diagram of the installation of the fixing plate at the bottom of the load-bearing plate in Example 2 of the present invention.

[0031] Figure 11 This is a schematic structural diagram of the push handle of Example 2 of the present invention.

[0032] Figure 12 This is a schematic diagram of the platform mode of Example 2 of the present invention.

[0033] Figure 13 This is a schematic diagram of the platform implementation mode of Example 2 of the present invention.

[0034] Figure 14 This is a schematic diagram of the platform towing mode of embodiment 2 of the present invention.

[0035] Figure 15 This is a structural diagram of Example 3 of the present invention when the operating handle is located in the second position and the caster unit is located in the unfolded rolling position.

[0036] Figure 16 This is a structural diagram of Example 3 of the present invention, in which the load-bearing plate is omitted when the operating handle is located in the second position and the caster unit is located in the unfolded rolling position.

[0037] Figure 17 This is a schematic structural diagram of the operating handle of Example 3 of the present invention.

[0038] Figure 18 This is a schematic diagram of the decomposition structure of Example 4 of the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the accompanying drawings, which are for illustrative purposes only and are not to be construed as limiting the present invention.

[0040] To more concisely illustrate this embodiment, some components well known to those skilled in the art but not relevant to the main content of this invention may be omitted from the drawings or descriptions. In addition, for ease of description, some components may be omitted, enlarged, or reduced in size in the drawings, but they do not represent the dimensions or entire structure of the actual product.

[0041] Example 1

[0042] like Figure 1 and Figure 2 As shown, the present invention provides a flatbed cart with a foldable caster unit, comprising a load-bearing plate 1, a load-bearing support frame 2 and a caster unit 3, wherein the load-bearing support frame 2 is arranged at the bottom of the load-bearing plate 1, and the caster unit 3 is installed on the load-bearing support frame 2 and can rotate between a folded storage position and an unfolded rolling position around the corresponding caster unit pivot axis, and the load-bearing support frame 2 is a frame body bent into a U shape by a round tube, and the caster unit 3 comprises two front caster units arranged at the front of the load-bearing support frame 2 and two rear caster units arranged at the rear of the load-bearing support frame 2, and the caster unit 3 is linked to a caster unit rotation drive device, and the caster unit rotation drive device comprises an operating handle 4, a connecting rod 5, a front linkage mechanism 6 and a rear linkage mechanism 7.

[0043] like Figure 2As shown, the operating handle 4 is arranged on the lower surface of the load-bearing plate 1, and the operating handle 4 includes a U-shaped handle body, the handle body includes two side arms of an integral structure and a grip arranged between the two side arms to connect one end of the two side arms, and a rotating shaft 41 and a positioning shaft 42 are also provided between the two side arms. The rotating shaft 41 is provided at the end of the two side arms opposite to the grip, and two mounting platforms 8 for placing the rotating shaft 41 are symmetrically provided on the lower surface of the load-bearing plate 1 at the position corresponding to the rotating shaft 41. The distance between the outer sides of the two mounting platforms 8 is equivalent to the axial length of the rotating shaft 41, and a semi-circular groove is provided on the top surface of the mounting platform 8. The rotating shaft 41 is placed in the semi-circular groove. A pressing plate 9 with a semi-circular groove is provided on the back cover, and the pressing plate The plate 9 is fixed to the mounting table 8 by screws, and two groups of positioning clips 10 are provided on the lower surface of the load-bearing plate 1. The two groups of positioning clips 10 are symmetrically fixed on the lower surface of the load-bearing plate 1 at positions corresponding to the positioning axes 42 with the rotating shaft 41 as the symmetry axis. The positioning axes 42 can be inserted into the positioning clips 10 to fix the operating handle 4. The positions of the operating handle 4 when the positioning axes 41 of the operating handle 4 are inserted into the two groups of positioning clips 10 correspond to the first position and the second position of the operating handle 4, that is, when the operating handle 4 is parallel to the load-bearing plate 1, the first position corresponds to the position of the operating handle 4 when the positioning axis 42 is located to the left of the rotating shaft 41, and the second position corresponds to the position of the operating handle 4 when the positioning axis 42 is located to the right of the rotating shaft 41.

[0044] like Figure 3 As shown, the side arm of the operating handle 4 is provided with a lug 43 on one end provided with a rotating shaft 41. The lug 43 is perpendicular to the side arm, and a sliding sleeve 44 is connected to the free end of the lug 43. The sliding sleeve 44 is mounted on the connecting rod 5 and can slide along the connecting rod 5. In this embodiment, the connecting rod 5 is an elongated square tube, and the front and rear ends of the connecting rod 5 are both inserted with a rotating sleeve 11. In this embodiment, the front linkage mechanism 6 includes a front drive tube 61, a front support arm 62, and a front fixed seat 63. The front drive tube 61 is rotatably connected to the connecting rod 5. One end of the front support arm 62 is connected and fixed to the front drive tube 61, and the other end of the front support arm 62 is pivotally connected to the front fixed seat 63. The front fixed seat 63 is connected and fixed to the load-bearing plate 1. The rear linkage mechanism 7 includes a rear drive tube 71, a rear support arm 72 and a rear fixed seat 73. The rear drive tube 71 is rotatably connected to the connecting rod 5. One end of the rear support arm 72 is connected and fixed to the rear drive tube 71. The other end of the rear support arm 72 is pivotally connected to the rear fixed seat 73. The rear fixed seat 73 is connected and fixed to the load-bearing plate 1.

[0045] like Figure 4As shown, the rotating sleeve 11 includes an integrally structured collar 112 and a latch 111. The latch 111 is inserted into the end of the connecting rod 5 and fixed to the connecting rod 5. The collar 112 of the rotating sleeve 5 at the front end of the connecting rod 5 is sleeved on the front drive tube 61 and can rotate relative to the front drive tube 61. The collar 112 of the rotating sleeve 11 at the rear end of the connecting rod 5 is sleeved on the rear drive tube 71 and can rotate relative to the rear drive tube 71. The annular wall of the collar 112 is provided with a strip-shaped through hole 113 running along the circumference. A limit screw 114 is provided in the strip-shaped through hole 113 and is threadedly connected to the drive tube. The limit screw 114 cooperates with the strip-shaped through hole 113 to prevent the rotating sleeve 11 from moving in the axial direction of the drive tube and to limit the rotation angle of the rotating sleeve 11 relative to the drive tube.

[0046] like Figure 5 As shown, in this embodiment, the caster unit 3 includes a fixed sleeve 31, a rotating block 32, a caster frame 33, a caster 34 and a reset device. The lower part of the fixed sleeve 31 is provided with a recess, and the rotating block 32 is placed in the recess. The fixed sleeve 31 and the rotating block 32 are both mounted on the load-bearing support frame 2, and the fixed sleeve 31 is connected and fixed to the load-bearing plate 1, the caster frame 33 is connected and fixed to the rotating block 32, and the caster 34 is rotatably installed on the caster frame 33. The reset device is a torsion spring 35, which is mounted on the load-bearing support frame 2, and the two ends of the torsion spring 35 are respectively against the fixed sleeve 31 and the rotating block 32 to provide elastic force for the rotating block 32 to rotate and reset relative to the fixed sleeve 31. A clamping column 36 is provided on the inner side of the rotating block 32, and the clamping column 36 has a stepped column body. The clamping column 36 passes through the rotating block 32 and is fixed to the rotating block 32 by tightening with a nut.

[0047] like Figure 6 and Figure 7As shown, when the operating handle 4 is rotated from the first position to the second position, the lug 43 is converted from the upward state in the first position to the downward state in the second position, and the sliding sleeve 44 drives the connecting rod 5 downward away from the load-bearing plate 1 while sliding axially along the connecting rod 5. The connecting rod 5 drives the front drive tube 61 and the rear drive tube 71 to rotate around the pivot axis of the support arm. The two ends of the front drive tube 61 collide with the inner sides of the rotating blocks 32 of the two front wheel units, forcing the rotating blocks 32 to rotate relative to the fixed sleeve 31 to realize the two front wheel units to open to the unfolded rolling position. At the same time, the two ends of the rear drive tube 71 collide with the inner sides of the sliding blocks 32 of the two rear wheel units, forcing the rotating blocks 32 to rotate relative to the fixed sleeve 31 to realize the two rear wheel units to open to the unfolded rolling position. On the contrary, when the operating handle 4 is rotated from the second position to the first position, the lug 43 is converted from the downward state in the second position to the upward state in the first position, and the sliding sleeve 44 drives the connecting rod 5 upward toward the load-bearing plate 1 while sliding axially along the connecting rod 5. The connecting rod 5 drives the front drive tube 61 and the rear drive tube 71 to rotate around the pivot axis of the support arm. The two ends of the front drive tube 61 are disengaged from the inner side of the sliding block 32 of the two front wheel units, and the two front wheel units are rotated and reset to the folded storage position under the action of the torsion spring 35. At the same time, the two ends of the rear drive tube 71 are disengaged from the inner side of the sliding block 32 of the two rear wheel units, and the two rear wheel units are rotated and reset to the folded storage position under the action of the torsion spring 35.

[0048] like Figure 8 As shown, as a further improvement, the ends of the front drive tube 61 and the rear drive tube 71 are provided with a locking plug 74 that cooperates with the clamping column 36 provided on the inner side of the rotating block 32, and the locking plug 74 is provided with a clamping groove 741. The clamping column 36 can be clamped into the clamping groove 741 when the front caster unit and the rear caster unit are rotated to the unfolded rolling position.

[0049] Example 2

[0050] like Figure 9 and Figure 10 As shown, this embodiment is similar to embodiment 1, the difference being that a pushing handle 12 is provided on the upper surface of the load-bearing plate 1, and the pushing handle 12 includes two vertical rods, and the bottom ends of the two vertical rods are pivotally connected to a fixing seat 13, and the fixing seat 13 is mounted on the load-bearing support frame 1 at a position behind the rear caster unit, and the fixing seat 13 is fixed by a fixing plate 14 provided on the lower surface of the load-bearing plate 1 and connected and fixed to the load-bearing plate 1 and the fixing seat 13, and the fixing plate 14 is connected and fixed to the load-bearing plate 1 and the fixing seat 13 by screws, and the pushing handle 12 can rotate around the pivot axis of the pushing handle, and a receiving groove 15 for receiving the pushing handle 12 is provided on the upper surface of the load-bearing plate 1, and when the pushing handle 12 is received in the receiving groove 15, the surface of the pushing handle 12 is flush with or lower than the upper surface of the load-bearing plate 1.

[0051] like Figure 11 As shown, in this embodiment, the two vertical rods are two-stage telescopic rods, which include a lower rod 121 and an upper rod 122. A first crossbar 123 is connected to the top of the two lower rods 121. The first crossbar 123 is provided with an upper rod locking mechanism 1231 capable of locking the upper rod 122. The upper rod locking mechanism 1231 includes a lock pin placed inside the first crossbar, a return spring, and a control push block provided outside the first crossbar and connected to the lock pin. The tops of the two upper rods 122 are connected to a second crossbar 123. The second crossbar 124 is for the user to grasp and operate the push handle 12. The control push block is provided with a hook, which can be locked with the load-bearing plate 1 when the push handle 12 is stored in the storage slot 15 to fix the push handle 12. A reinforcing rod 125 is connected between the two fixing seats 13, and a locking mechanism 1251 is provided on the reinforcing rod 125 to lock the rotation of the push handle 12. The locking mechanism 1251 is similar to the upper rod locking mechanism 1231, except that the control push block of the locking mechanism 1251 is not provided with a hook.

[0052] like Figures 12 to 14 As shown, the locking mechanism 1251 can lock the pushing handle 12 relative to the load-bearing plate 1 so that it cannot rotate when the pushing handle 12 is stored in the storage slot 15, at a position 90 degrees perpendicular to the load-bearing plate 1, and at a rotation angle of 135 degrees relative to the load-bearing plate 1. Through the cooperation of the pushing handle 12 and the locking mechanism 1251, the flatbed cart with a foldable caster unit provided in this embodiment has three working modes, specifically a platform mode when the pushing handle 12 is stored in the storage slot 15, a platform pushing mode when the pushing handle 12 is at a position 90 degrees perpendicular to the load-bearing plate 1, and a platform towing mode when the pushing handle 12 is rotated at a angle of 135 degrees relative to the load-bearing plate 1.

[0053] Example 3

[0054] This embodiment is similar to the first embodiment, except that the structure of the operating handle and the connecting rod of this embodiment are different from those of the first embodiment.

[0055] like Figures 15 to 17As shown, in this embodiment, the operating handle 4b is provided on the upper surface of the load-bearing plate 1, and the operating handle 4b includes a U-shaped handle body, which includes two side arms of an integral structure and a grip provided between the two side arms to connect one end of the two side arms. The operating handle 4b is symmetrically provided with cylindrical bosses 4b1 on the inner sides of the two side arms, and the cylindrical bosses 4b1 are rotatably connected to the load-bearing plate. The outer sides of the side arms are provided with a first connecting shaft 4b2 and a second connecting shaft 4b3 at positions on both sides of the cylindrical bosses 4b1, respectively. The connecting rod includes a front connecting rod 51 and a rear connecting rod 52. The front link 51 and the rear link 52 are staggered in the axial direction of the pivot axis of the operating handle 4b, and circular holes are provided at both the front and rear ends of the front link 51. The front end of the front link 51 is sleeved on the front drive tube 61 and is rotatably connected to the front drive tube 61, and the rear end of the front link 51 is sleeved on the first connecting shaft 4b2 and is rotatably connected to the first connecting shaft 4b2. Circular holes are provided at both the front and rear ends of the rear link 52, and the rear end of the rear link 52 is sleeved on the rear drive tube 71 and is rotatably connected to the rear drive tube 71. The front end of the rear link 52 is sleeved on the second connecting shaft 4b3 and is rotatably connected to the second connecting shaft 4b3. In this way, when the operating handle 4b is flipped 180 degrees from the first position parallel to the load-bearing plate 1 to the second position, the positions of the first connecting shaft 4b2 and the second connecting shaft 4b3 change at the same time and pull the front link 51 and the rear link 52 to move respectively. Moreover, the front link 51 and the rear link 52 will not interfere with each other during movement due to the staggered arrangement. The front link 51 pulls the front drive tube 61 to force the front caster to open to the expanded rolling position, and the rear link 52 pulls the rear drive tube 71 to force the rear caster unit to open to the expanded rolling position, thereby realizing the opening of the caster unit 3.

[0056] Example 4

[0057] like Figure 18 As shown, this embodiment is similar to embodiment 3, the difference being that a push handle 12 is provided on the upper surface of the load-bearing plate 1. The structure of the push handle 12 and the connection method between the push handle 12 and the load-bearing plate 1 of this embodiment are similar to those of embodiment 2.

[0058] The embodiments of the present invention described above do not limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A flatbed cart with foldable caster units, comprising a load-bearing plate, a load-bearing support frame, and caster units, wherein the load-bearing support frame is disposed at the bottom of the load-bearing plate, and the caster units are mounted on the load-bearing support frame and are capable of rotating about corresponding caster unit pivot axes between a folded storage position and an unfolded rolling position, wherein the caster units include front caster units and rear caster units, and are characterized in that: The caster unit rotation drive device is further included, and the caster unit rotation drive device includes an operating handle, a connecting rod, a front linkage mechanism and a rear linkage mechanism. The operating handle is pivotally connected to the load-bearing plate and can rotate around the operating handle pivot axis. The connecting rod is connected to the operating handle, the front linkage mechanism is connected to the connecting rod and the front caster unit, and the rear linkage mechanism is connected to the connecting rod and the rear caster unit. When the operating handle is rotated from the first position to the second position, the operating handle can link the front linkage mechanism and the rear linkage mechanism through the connecting rod to respectively drive the front caster unit and the rear caster unit to rotate from the folded storage position to the unfolded rolling position. The front caster unit and the rear caster unit are both provided with a reset device, and when the operating handle is rotated from the second position to the first position, the front caster unit and the rear caster unit can be rotated from the unfolded rolling position to the folded storage position under the action of the reset device; The front linkage mechanism includes a front drive tube, a front support arm and a front fixed seat, the front drive tube is rotatably connected to the connecting rod, one end of the front support arm is connected and fixed to the front drive tube, the other end of the front support arm is pivotally connected to the front fixed seat, and the front fixed seat is connected and fixed to the load-bearing plate, and the front drive tube is configured so that when the operating handle is rotated from the first position to the second position, the end of the front drive tube can contact the inner side surface of the front caster unit to drive the front caster unit to rotate and open to the unfolded rolling position; The rear linkage mechanism includes a rear drive tube, a rear support arm and a rear fixed seat, the rear drive tube is rotatably connected to the connecting rod, one end of the rear support arm is connected and fixed to the rear drive tube, the other end of the rear support arm is pivotally connected to the rear fixed seat, and the rear fixed seat is connected and fixed to the load-bearing plate, and the rear drive tube is configured so that when the operating handle is rotated from the first position to the second position, the end of the rear drive tube can contact the inner side surface of the rear caster unit to drive the rear caster unit to rotate and open to the unfolded rolling position; The front end and the rear end of the connecting rod are both inserted with a rotating sleeve, the front driving tube is rotatably connected to the connecting rod through the rotating sleeve, and the rear driving tube is rotatably connected to the connecting rod through the rotating sleeve.

2. The flatbed cart with foldable caster units according to claim 1, wherein: A pushing handle is provided on the upper surface of the load-bearing plate, and the pushing handle includes two vertical rods. The bottom ends of the two vertical rods are pivotally connected to fixed seats. The fixed seats are mounted on the load-bearing support frame and fixed at a position behind the rear caster unit. The pushing handle can rotate around the pivot axis of the pushing handle. A reinforcing rod is connected between the two fixed seats, and the reinforcing rod is provided with a locking mechanism that can lock the rotation of the pushing handle.

3. The flatbed cart with foldable caster units according to claim 2, wherein: The operating handle is arranged on the lower surface of the load-bearing plate, and a lug is provided on the operating handle, and the lug is connected to a sliding sleeve. The sliding sleeve is mounted on the connecting rod and can slide along the connecting rod. The front end and the rear end of the connecting rod are rotatably connected to the front drive tube and the rear drive tube respectively. The lug is configured to drive the connecting rod away from or close to the load-bearing plate when the operating handle rotates between the first position and the second position.

4. The flatbed cart with foldable caster units according to claim 3, wherein: The operating handle includes a U-shaped handle body, which includes two side arms of an integral structure and a grip arranged between the two side arms to connect one end of the two side arms. A rotating shaft and a positioning shaft are also provided between the two side arms. The rotating shaft is provided at the end of the two side arms opposite to the grip. Two mounting platforms for placing the rotating shafts are symmetrically provided on the lower surface of the load-bearing plate at a position corresponding to the rotating shaft. A semi-circular groove is provided on the top surface of the mounting platform. The rotating shaft is placed in the semi-circular groove and is fixed with a pressure plate provided with a semi-circular groove on the back cover. Two groups of positioning clips are provided on the lower surface of the load-bearing plate. The two groups of positioning clips are symmetrically fixed to the positions corresponding to the positioning shafts on the lower surface of the load-bearing plate with the rotating shaft as the symmetry axis. The positioning shaft can be respectively clamped into the two groups of positioning clips when the operating handle is in the first position and the second position to fix the operating handle.

5. The flatbed cart with foldable caster units according to claim 2, wherein: The operating handle is arranged on the upper surface of the load-bearing plate, and the operating handle is respectively provided with a first connecting shaft and a second connecting shaft at positions on both sides of the operating handle pivot axis. The connecting rod includes a front connecting rod and a rear connecting rod, and the front connecting rod and the rear connecting rod are staggered in the axial direction of the operating handle pivot axis. One end of the front connecting rod is rotatably connected to the front drive tube, and the other end of the front connecting rod is rotatably connected to the first connecting shaft, one end of the rear connecting rod is rotatably connected to the rear drive tube, and the other end of the rear connecting rod is rotatably connected to the second connecting shaft.

6. The flatbed cart with foldable caster units according to claim 5, characterized in that: The control lever is pivotally connected to the side panel that is located adjacent to the control lever, and the rear end of the control lever is pivotally connected to the side panel that is located adjacent to the control lever, and the rear end of the control lever is pivotally connected to the side panel that is located adjacent to the control lever.

7. A flatbed cart with foldable caster units according to any one of claims 3 to 6, characterized in that: The ends of the front drive tube and the rear drive tube are both provided with locking plugs, and the locking plugs are provided with card slots. The front caster unit and the rear caster unit are provided with card columns at positions corresponding to the card slots, and the card columns are configured to be able to be locked into the card slots when the front caster unit and the rear caster unit are rotated to the unfolded rolling position.

8. The flatbed cart with foldable caster units according to claim 7, wherein: The caster unit includes a fixed sleeve, a rotating block, a caster frame and a caster. A recess is provided at the lower part of the fixed sleeve, and the rotating block is placed in the recess. The fixed sleeve and the rotating block are both mounted on the load-bearing support frame, and the fixed sleeve is connected and fixed to the load-bearing plate. The caster frame is connected and fixed to the rotating block. The caster is rotatably installed on the caster frame. The reset device is a torsion spring, which is mounted on the load-bearing support frame, and the two ends of the torsion spring are respectively against the fixed sleeve and the rotating block to provide a force for the rotating block to rotate relative to the fixed sleeve. The clamping column is provided on the inner side of the rotating block.

Images