Automatic wheel chock folding and unfolding device and carrying truck

Abstract

The utility model relates to the technical field of heavy truck braking, in particular to an automatic wheel chock folding and unfolding device and a carrying truck, the automatic wheel chock folding and unfolding device comprises a support used for being connected with the truck, a first driving mechanism, a folding and unfolding assembly and a wheel chock, the support is fixedly arranged beside tires of the truck, and the folding and unfolding assembly is movably connected with the support; the first driving mechanism is connected with the bracket and the folding and unfolding assembly and is used for driving the folding and unfolding assembly to move; and the wheel chock is movably arranged on the folding and unfolding assembly. The wheel chock can be automatically placed and withdrawn, and the burden of workers can be relieved.

Description

Technical Field

[0001] The utility model relates to the technical field of heavy truck braking, and more specifically, to an automatic wheel chock retracting and releasing device and a transport truck. Background Art

[0002] When some heavy trucks, such as trucks, concrete trucks, trucks and other special vehicles are parked, in order to ensure safety, it is often necessary to place wheel chocks to limit the tires of the car to prevent the car from sliding down the slope due to its own weight when there is a small slope on the ground.

[0003] A Chinese patent discloses a truck wheel chock, comprising a wheel chock body, a ratchet wheel rotatably provided at the bottom of the wheel chock body, and the axis of the ratchet wheel is arranged in a horizontal direction; when the wheel chock body contacts the truck tire, the axis of the ratchet wheel is parallel to the axis of the truck tire; a pawl cooperating with the ratchet wheel is also provided in the wheel chock body, and the pawl can limit the rotation of the ratchet wheel in the direction of the truck tire retreating. The following takes a tank truck as an example. When the tank truck is refueling, the operator needs to bend down manually to place the wheel chock as required. However, the number of times of refueling is high every day, and the operator bends down frequently, which can easily cause lumbar diseases. Therefore, a wheel chock automatic retracting and releasing device is needed to reduce the workload of the operator. Utility Model Content

[0004] The utility model aims to overcome the shortcomings of the prior art and provides an automatic wheel chock retracting and releasing device, which can automatically place or retract the wheel chock.

[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0006] Provided is an automatic wheel chock retracting and extending device, comprising a bracket for connecting to a truck, a first driving mechanism, a retracting and extending assembly and a wheel chock, wherein the bracket is fixedly mounted beside a truck tire, and the retracting and extending assembly is movably connected to the bracket; the first driving mechanism connects the bracket and the retracting and extending assembly and is used for driving the retracting and extending assembly to move; and the wheel chock is movably mounted on the retracting and extending assembly.

[0007] With this arrangement, the automatic wheel chock retracting and releasing device is fixed on the vehicle body through a bracket and is located next to the tire; when the truck needs to place the wheel chock when parking, the first drive mechanism drives the retracting and releasing assembly to move down along the bracket until the retracting and releasing assembly contacts the ground, and then the retracting and releasing assembly sends out the wheel chock, causing the wheel chock to fit into the angle formed between the tire and the ground, thereby completing the placement of the wheel chock; when the truck needs to start and move, the retracting and releasing assembly retracts the wheel chock by magnetic adsorption or chain pulling, and then the first drive mechanism drives the retracting and releasing assembly to rise along the bracket, causing the retracting and releasing assembly to reset, thereby completing the automatic retraction of the wheel chock.

[0008] Preferably, the retractable assembly includes a chassis, a chain retractable assembly and a push-out assembly, the chain retractable assembly and the push-out assembly are both installed on the chassis, the wheel chock is placed on the chassis, and the push-out assembly is arranged between the chain retractable assembly and the wheel chock; the chain retractable assembly includes a chain winder and a chain, the chain is movably passed through the push-out assembly, one end of the chain is connected to the chain winder, and the other end is connected to the wheel chock, the push-out assembly is used to push the wheel chock out of the chassis, and an opening is provided on the chassis for the wheel chock to enter and exit.

[0009] With this arrangement, when the wheel chock needs to be placed, the push-out assembly and the chain winder work together, the push-out assembly pushes the wheel chock out of the chassis and then resets it, the chain winder releases the chain, and the chain moves with the wheel chock; when the wheel chock needs to be retracted, the chain winder works to wind the chain, and the chain drives the wheel chock back into the chassis.

[0010] Furthermore, the ejection assembly includes an ejection cylinder and an ejection plate, the ejection plate is provided with a through hole, the chain is movably arranged through the through hole and connected to the wheel chock, the ejection cylinder is installed on the chassis, and the ejection plate is slidably connected to the chassis through the ejection cylinder. With this arrangement, when placing the wheel chock, the ejection cylinder drives the ejection plate to move, pushing the wheel chock to move until the wheel chock contacts the tire, and the ejection cylinder is reset; when the wheel chock needs to be retracted, the chain retracts through the ejection plate, driving the wheel chock to move to the chassis, and the recovery is completed.

[0011] Preferably, the retractable assembly includes a chassis, a second driving mechanism and an electromagnet. The chassis is movably connected to the bracket, the second driving mechanism is fixedly mounted on the chassis, and the second driving mechanism is connected to the electromagnet. The second driving mechanism is used to drive the electromagnet to move on the chassis, and the electromagnet is used to absorb the wheel chock. The wheel chock is placed on the chassis, and an opening is provided on the chassis for the wheel chock to enter and exit.

[0012] Through this arrangement, when it is necessary to place a wheel chock, the chassis moves down along the bracket and abuts the ground, and the second drive mechanism drives the electromagnet to push out the wheel chock. At this time, the electromagnet is not energized and has no magnetic attraction effect. After the wheel chock is pushed out to the side of the tire, the second drive mechanism drives the electromagnet to retract, thereby completing the placement of the wheel chock; when it is necessary to recover the wheel chock, the second drive mechanism drives the electromagnet to extend, and the electromagnet is energized to absorb the wheel chock. Subsequently, the second drive mechanism drives the wheel chock to return through the electromagnet, and the wheel chock is reset to the chassis. Subsequently, the chassis moves up along the bracket and resets to its original position, thereby completing the recovery of the wheel chock.

[0013] Preferably, the bracket includes a first mounting plate for connecting to the vehicle body and two guide plates, the two guide plates are fixedly mounted on the bottom of the first mounting plate, and the two guide plates are parallel to each other, and a moving space for the folding and unfolding components is formed between the guide plates. Two sliding plates are provided on the chassis, and the two sliding plates are slidably connected to the two guide plates respectively. One end of the first driving mechanism is connected to the first mounting plate, and the other end is connected to the chassis.

[0014] Through this arrangement, the first mounting plate is fixedly connected to the body of the truck, the guide plate guides the movement of the retractable assembly, and the chassis is slidably connected to the guide plate via a sliding plate, thereby preventing the retractable assembly from being offset due to vibration when the first driving mechanism drives the retractable assembly to move downward, thereby ensuring that the retractable assembly can be accurately positioned at the preset position and the wheel chock can be released to the side of the tire.

[0015] Furthermore, a guide groove is provided on the guide plate, and a protrusion is provided on the sliding plate. The protrusion cooperates with the guide groove, and the protrusion can slide along the guide groove.

[0016] Preferably, the first driving mechanism includes a second mounting plate, a piston rod and a first cylinder, the first cylinder is fixedly mounted on the first mounting plate, the second mounting plate is fixedly connected to the chassis, one end of the piston rod is fixedly connected to the second mounting plate, and the other end forms a piston transmission pair with the first cylinder.

[0017] Through this arrangement, when the retractable assembly needs to be lowered, the first cylinder is inflated, the air pressure increases, the first cylinder and the piston rod move relatively away from each other, and the piston rod pushes the retractable assembly to move downward; when the retractable assembly needs to be moved upward, the first cylinder is exhausted, the air pressure decreases, the first cylinder and the piston rod move relatively close to each other, and the piston rod drives the retractable assembly to rise.

[0018] Preferably, the wheel chock comprises a wheel blocking portion and an adsorption portion, the wheel blocking portion is a triangular pyramid structure, the adsorption portion is fixedly connected to the wheel blocking portion, and the adsorption portion is located close to the electromagnet end.

[0019] Through this arrangement, the triangular pyramid structure of the wheel block can be better embedded between the tire and the ground, and the force is stable to prevent the wheel block from sliding; the adsorption part is used to produce a magnetic attraction effect with the electromagnet, and is arranged next to the wheel block, which can not only ensure stable adsorption, but also will not affect the wheel block to limit the tire.

[0020] Preferably, the blocking wheel portion is further provided with a plurality of grooves for increasing resistance.

[0021] This arrangement can further increase the friction between the wheel blocking portion and the tire, which is beneficial for maintaining relative stillness between the wheel blocking portion and the tire, further improving the stability of the wheel chock and improving safety performance.

[0022] Preferably, the second driving mechanism comprises a piston column and a second cylinder, the second cylinder is fixedly connected to the chassis, one end of the piston column is fixedly connected to the electromagnet, and the other end forms a piston transmission pair with the second cylinder.

[0023] With this arrangement, when the electromagnet needs to be extended, the second cylinder is inflated, the piston rod extends outward, and drives the electromagnet to extend; when the electromagnet needs to be retracted, the second cylinder is exhausted, the piston rod retracts into the second cylinder, and drives the electromagnet to retract.

[0024] Preferably, a guide portion for guiding the wheel chock to enter is further provided at the opening of the chassis, the width of the guide portion is greater than the width of the wheel chock, and the guide portion is in a trapezoidal structure with a width gradually decreasing from close to the opening to far away from the opening.

[0025] With this arrangement, when the electromagnet attracts the wheel chock and retracts, the wheel chock first enters the guide portion, which is wider than the wheel chock, making it easier for the wheel chock to enter. Then, inside the guide portion, the wheel chock adjusts its posture as it moves inside the trapezoidal guide portion, and is finally stored inside the chassis.

[0026] Preferably, the end of the guide portion is also provided with a slope for facilitating the entry of the wheel chock.

[0027] With this arrangement, when the electromagnet attracts the wheel chock for recovery, the slope facilitates the wheel chock to enter the guide portion, thereby avoiding jamming due to the thickness of the guide portion.

[0028] Preferably, the first mounting plate is provided with a mounting hole for fixed connection with a truck.

[0029] With this arrangement, the first mounting plate can be fixedly connected to the truck via fixing components such as bolts.

[0030] A transport truck comprises a truck body and an automatic wheel chock retracting and extending device as described in any one of the above items, wherein the automatic wheel chock retracting and extending device is installed beside the tire of the truck body and connected to the crossbeam of the truck body through a bracket.

[0031] Compared with the prior art, the beneficial effects of the utility model are:

[0032] (1) The wheel chocks can be automatically placed and recovered, greatly reducing the workload of operators.

[0033] (2) The sliding connection between the guide plate and the sliding plate ensures that the movement path of the retractable assembly is stable, thereby improving the accuracy of the wheel chock placement position.

[0034] (3) The chassis is provided with guides and slopes to facilitate the entry of the wheel chocks, ensuring that the wheel chocks are stored in the chassis in the correct posture. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of a first embodiment of an automatic wheel chock retracting and releasing device of the utility model;

[0036] Figure 2 This is a schematic diagram of the wheel chock structure of the second embodiment of the wheel chock automatic retracting and releasing device of the utility model;

[0037] Figure 3 This is a schematic diagram of a third embodiment of the automatic wheel chock retracting and releasing device of the utility model in a wheel chock placement state;

[0038] Figure 4 This is a schematic diagram of a third embodiment of the automatic wheel chock retracting and releasing device of the utility model, in which the wheel chock is retracted;

[0039] Figure 5 It is a schematic diagram of the automatic wheel chock retracting and releasing device of a transport truck according to the utility model, in which the wheel chock is retracted;

[0040] Figure 6 The utility model is a schematic diagram of placing wheel chocks in an automatic wheel chock retracting and releasing device for a transport truck.

[0041] The illustrations are as follows:

[0042] 1. Bracket; 11. First mounting plate; 111. Mounting hole; 12. Guide plate; 2. First driving mechanism; 21. Second mounting plate; 22. Piston rod; 23. First cylinder; 3. Retractable assembly; 31. Chassis; 311. Sliding plate; 312. Guide part; 313. Slope; 32. Second driving mechanism; 321. Second cylinder; 322. Piston column; 33. Electromagnet; 4. Wheel chock; 41. Wheel blocking part; 411. Groove; 42. Adsorption part; 5. Truck body. DETAILED DESCRIPTION

[0043] The utility model is further described below in conjunction with specific implementation methods. The drawings are only used for exemplary descriptions, and are only schematic diagrams, not actual pictures, and cannot be understood as limitations on this patent; in order to better illustrate the embodiments of the utility model, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0044] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0045] Example 1

[0046] like Figure 1 The figure shows a first embodiment of an automatic wheel chock retracting and extending device of the utility model, comprising a bracket 1 for connecting to a truck, a first driving mechanism 2, a retracting and extending assembly 3 and a wheel chock 4, wherein the bracket 1 is fixedly mounted beside the truck tire, and the retracting and extending assembly 3 is movably connected to the bracket 1; the first driving mechanism 2 connects the bracket 1 and the retracting and extending assembly 3, and is used for driving the retracting and extending assembly 3 to move; the wheel chock 4 is movably mounted on the retracting and extending assembly 3.

[0047] Through this arrangement, the automatic wheel chock retracting and releasing device is fixedly mounted on the vehicle body through the bracket 1 and is located next to the tire; when the truck needs to place the wheel chock 4 when parking, the first drive mechanism 2 drives the retracting and releasing assembly 3 to move downward along the bracket 1 until the retracting and releasing assembly 3 contacts the ground, and then the retracting and releasing assembly 3 sends out the wheel chock 4, so that the wheel chock 4 is stuck next to the tire, thereby completing the placement of the wheel chock 4; when the truck needs to start and move, the retracting and releasing assembly 3 retracts the wheel chock 4 by magnetic adsorption or chain pulling, and then the first drive mechanism 2 drives the retracting and releasing assembly 3 to rise along the bracket 1, so that the retracting and releasing assembly 3 is reset, thereby completing the automatic recovery of the wheel chock 4.

[0048] As an embodiment of the utility model, the retractable assembly 3 includes a chassis 31, a second driving mechanism 32 and an electromagnet 33. The chassis 31 is movably connected to the bracket 1, the second driving mechanism 32 is fixedly mounted on the chassis 31, and the second driving mechanism 32 is connected to the electromagnet 33. The second driving mechanism 32 is used to drive the electromagnet 33 to move on the chassis 31, and the electromagnet 33 is used to absorb the wheel chock 4. The wheel chock 4 is placed on the chassis 31, and an opening is opened on the chassis 31 for the wheel chock 4 to enter and exit.

[0049] Through this arrangement, when it is necessary to place the wheel chock 4, the chassis 31 moves down along the bracket 1 and abuts against the ground, and the second driving mechanism 32 drives the electromagnet 33 to push out the wheel chock 4. At this time, the electromagnet 33 is not energized and has no magnetic attraction effect. After the wheel chock 4 is pushed out to the side of the tire, the second driving mechanism 32 drives the electromagnet 33 to retract, thereby completing the placement of the wheel chock 4; when it is necessary to recover the wheel chock 4, the second driving mechanism 32 drives the electromagnet 33 to extend, and the electromagnet 33 is energized to absorb the wheel chock 4. Subsequently, the second driving mechanism 32 drives the wheel chock 4 to return through the electromagnet 33, and the wheel chock 4 is reset to the chassis 31. Subsequently, the chassis 31 moves up along the bracket 1 and resets to its original position, thereby completing the recovery of the wheel chock 4.

[0050] As an embodiment of the utility model, the bracket 1 includes a first mounting plate 11 for connecting to the vehicle body and two guide plates 12. The two guide plates 12 are fixedly mounted at the bottom of the first mounting plate 11, and the two guide plates 12 are parallel to each other. A moving space for the retractable component 3 is formed between the guide plates 12. Two sliding plates 311 are provided on the chassis 31. The two sliding plates 311 are respectively slidably connected to the two guide plates 12. One end of the first driving mechanism 2 is connected to the first mounting plate 11, and the other end is connected to the chassis 31.

[0051] Through this arrangement, the first mounting plate 11 is fixedly connected to the body of the truck, the guide plate 12 guides the movement of the retractable assembly 3, and the chassis 31 is slidably connected to the guide plate 12 via the sliding plate 311, thereby preventing the retractable assembly 3 from being offset due to vibration when the first driving mechanism 2 drives the retractable assembly 3 to move downward, thereby ensuring that the retractable assembly 3 can be accurately positioned at the preset position and the wheel chock 4 can be released to the side of the tire.

[0052] As an embodiment of the utility model, the first driving mechanism 2 includes a second mounting plate 21, a piston rod 22 and a first cylinder 23. The first cylinder 23 is fixedly mounted on the first mounting plate 11. The second mounting plate 21 is fixedly connected to the chassis 31. One end of the piston rod 22 is fixedly connected to the second mounting plate 21, and the other end forms a piston transmission pair with the first cylinder 23.

[0053] Through this arrangement, when it is necessary to lower the retractable component 3, the first cylinder 23 is inflated, the air pressure increases, the first cylinder 23 and the piston rod 22 move relatively away from each other, and the piston rod 22 pushes the retractable component 3 to move downward; when it is necessary to move the retractable component 3 upward, the first cylinder 23 is exhausted, the air pressure decreases, the first cylinder 23 and the piston rod 22 move relatively close to each other, and the piston rod 22 drives the retractable component 3 to rise.

[0054] As an embodiment of the present utility model, the second driving mechanism 32 includes a piston column 322 and a second cylinder 321, the second cylinder 321 is fixedly connected to the chassis 31, one end of the piston column 322 is fixedly connected to the electromagnet 33, and the other end forms a piston transmission pair with the second cylinder 321.

[0055] With this arrangement, when the electromagnet 33 needs to be extended, the second cylinder 321 is inflated, the piston rod 322 is extended outward, and the electromagnet 33 is extended; when the electromagnet 33 is retracted, the second cylinder 321 is exhausted, the piston rod 322 is retracted into the second cylinder 321, and the electromagnet 33 is retracted.

[0056] Example 2

[0057] like Figure 2 The second embodiment of the automatic wheel chock retracting and releasing device of the utility model is shown. This embodiment is similar to the first embodiment, except that the structure of the wheel chock 4 is different.

[0058] As an embodiment of the present utility model, the wheel stopper 4 includes a wheel blocking portion 41 and an adsorption portion 42 . The wheel blocking portion 41 is a triangular pyramid structure. The adsorption portion 42 is fixedly connected to the wheel blocking portion 41 . The adsorption portion 42 is located near the end of the electromagnet 33 .

[0059] Through this arrangement, the triangular pyramid structure of the wheel blocking portion 41 can be better embedded between the tire and the ground, and the force is stable, preventing the wheel chock 4 from sliding; the adsorption portion 42 is used to produce a magnetic attraction effect with the electromagnet 33, and is arranged next to the wheel blocking portion 41, which can ensure stable adsorption and will not affect the wheel blocking portion 41 to limit the tire.

[0060] As an embodiment of the present invention, the wheel blocking portion 41 is further provided with a plurality of grooves 411 for increasing resistance.

[0061] This arrangement can further increase the friction between the wheel blocking portion 41 and the tire, which is beneficial for the wheel blocking portion 41 and the tire to remain relatively still, further improving the stability of the wheel chock 4 and improving safety performance.

[0062] Example 3

[0063] like Figure 3 and Figure 4 The third embodiment of the automatic wheel chock retracting and releasing device of the utility model is shown. This embodiment is similar to the first embodiment, except that the structures of the chassis 31 and the first mounting plate 11 are different.

[0064] As an embodiment of the present utility model, a guide portion 312 for guiding the wheel chock 4 to enter is further provided at the opening of the chassis 31 . The guide portion 312 has a width greater than that of the wheel chock 4 and is in a trapezoidal structure.

[0065] With this arrangement, when the electromagnet 33 attracts the wheel chock 4 and retracts, the wheel chock 4 first enters the guide portion 312, which is wider than the wheel chock 4, making it easier for the wheel chock 4 to enter. Then, in the guide portion 312, the wheel chock 4 adjusts its posture as it moves in the trapezoidal guide portion 312, and is finally stored in the chassis 31.

[0066] As an embodiment of the present invention, a slope 313 is further provided at the end of the guide portion 312 to facilitate the entry of the wheel chock 4 .

[0067] With this arrangement, when the electromagnet 33 absorbs the wheel chock 4 for recovery, the slope 313 facilitates the wheel chock 4 to enter the guide portion 312 , thereby avoiding jamming due to the thickness of the guide portion 312 .

[0068] As an embodiment of the present utility model, the first mounting plate 11 is provided with a mounting hole 111 for fixedly connecting with a truck.

[0069] With this arrangement, the first mounting plate 11 can be fixedly connected to the truck by means of fixing components such as bolts.

[0070] Example 4

[0071] like Figure 5 and Figure 6 The figure shows an embodiment of a transport truck of the utility model, comprising a truck body 5 and an automatic wheel chock retracting and extending device as described in any one of embodiments 1 to 3, wherein the automatic wheel chock retracting and extending device is installed beside the tire of the truck body 5 and connected to the cross beam of the truck body 5 through a bracket 1.

[0072] Obviously, the above embodiments of the utility model are only examples for clearly explaining the utility model, and are not intended to limit the implementation methods of the utility model. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the utility model should be included in the protection scope of the claims of the utility model.

Claims

1. A wheel chock automatic retracting and releasing device, characterized in that: The invention comprises a support (1) for connecting with a truck, a first driving mechanism (2), a retractable assembly (3) and a wheel chock (4), wherein the support (1) is fixedly mounted beside the tire of the truck, and the retractable assembly (3) is movably connected with the support (1); the first driving mechanism (2) connects the support (1) and the retractable assembly (3) and is used to drive the retractable assembly (3) to move; the wheel chock (4) is movably mounted on the retractable assembly (3); The retractable assembly (3) comprises a chassis (31), a second driving mechanism (32) and an electromagnet (33); the chassis (31) is movably connected to the bracket (1); the second driving mechanism (32) is fixedly mounted on the chassis (31), and the second driving mechanism (32) is connected to the electromagnet (33); the second driving mechanism (32) is used to drive the electromagnet (33) to move on the chassis (31); the electromagnet (33) is used to absorb the wheel block (4); the wheel block (4) is placed on the chassis (31); and an opening is provided on the chassis (31) for the wheel block (4) to enter and exit; The first driving mechanism (2) comprises a second mounting plate (21), a piston rod (22) and a first cylinder (23); the first cylinder (23) is fixedly mounted on the first mounting plate (11); the second mounting plate (21) is fixedly connected to the chassis (31); one end of the piston rod (22) is fixedly connected to the second mounting plate (21), and the other end forms a piston transmission pair with the first cylinder (23).

2. The automatic wheel chock retracting and releasing device according to claim 1, characterized in that: The bracket (1) comprises a first mounting plate (11) for connecting to a vehicle body and two guide plates (12), the two guide plates (12) are fixedly mounted on the bottom of the first mounting plate (11), and the two guide plates (12) are parallel to each other, and a moving space for the retractable assembly (3) is formed between the guide plates (12); two sliding plates (311) are provided on the chassis (31), and the two sliding plates (311) are respectively slidably connected to the two guide plates (12); one end of the first driving mechanism (2) is connected to the first mounting plate (11), and the other end is connected to the chassis (31).

3. The automatic wheel chock retracting and releasing device according to claim 2, characterized in that: The wheel stopper (4) comprises a wheel blocking portion (41) and an adsorption portion (42); the wheel blocking portion (41) is a triangular pyramid structure; the adsorption portion (42) is fixedly connected to the wheel blocking portion (41); and the adsorption portion (42) is located close to the end of the electromagnet (33).

4. The automatic wheel chock retracting and releasing device according to claim 3, characterized in that: The blocking wheel portion (41) is also provided with a plurality of grooves (411) for increasing resistance.

5. The automatic wheel chock retracting and releasing device according to claim 1, characterized in that: The second driving mechanism (32) comprises a piston column (322) and a second cylinder (321); the second cylinder (321) is fixedly connected to the chassis (31); one end of the piston column (322) is fixedly connected to the electromagnet (33), and the other end forms a piston transmission pair with the second cylinder (321).

6. The automatic wheel chock retracting and releasing device according to claim 1, characterized in that: The opening of the chassis (31) is also provided with a guide portion (312) for guiding the wheel chock (4) to enter, the guide portion (312) having a width greater than the wheel chock (4), and the guide portion (312) is in a trapezoidal structure with a width gradually decreasing from close to the opening to far away from the opening.

7. The automatic wheel chock retracting and releasing device according to claim 6, characterized in that: The end of the guide portion (312) is also provided with a slope (313) for facilitating the entry of the wheel block (4).

8. A transport truck, characterized in that: The invention comprises a truck body (5) and an automatic wheel chock retracting and extending device as claimed in any one of claims 1 to 7, wherein the automatic wheel chock retracting and extending device is installed beside the tire of the truck body (5) and connected to the cross beam of the truck body (5) through a bracket (1).

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