A fork lift truck

Abstract

The utility model discloses a fork truck, include: portal assembly, the portal assembly includes outer portal and lever assembly, chassis assembly, the portal assembly with the chassis assembly is connected, wherein, the outer portal can be relative the chassis assembly and retract, the front end of outer portal is provided with support wheel, support wheel with lever assembly is connected, and under the driving of lever assembly, support wheel can rotate relative the outer portal. The utility model makes the portal assembly operation process, and support wheel touches the ground and will not produce any front and back inclination state, has guaranteed the stability and security in the process of forking goods.

Description

Technical Field

[0001] This utility model relates to the field of forklift technology, and in particular to a forklift. Background Technology

[0002] In related technologies, when the mast assembly of a forklift is running on the chassis to pick up goods, the mast assembly tilts forward and backward as it moves up and down the guide ramp of the chassis via rollers at the bottom of the mast assembly. This can easily cause instability during the movement of goods. Utility Model Content

[0003] This utility model aims to solve at least one of the technical problems existing in the prior art. To this end, one objective of this utility model is to provide a forklift in which the support wheel on the outer mast can be driven to rotate relative to the outer mast under the action of a lever assembly, so that when the support wheel touches the ground during the operation of the mast assembly, it will not tilt forward or backward, thus ensuring stability and safety during the process of picking up and picking up goods.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] An embodiment of the first aspect of this utility model provides a forklift, the forklift comprising: a mast assembly, the mast assembly including an outer mast and a lever assembly; a chassis assembly, the mast assembly being connected to the chassis assembly, wherein the outer mast can extend or retract relative to the chassis assembly; a support wheel is provided at the front end of the outer mast, the support wheel being connected to the lever assembly, and the support wheel being rotatable relative to the outer mast under the drive of the lever assembly.

[0006] In some embodiments, a support wheel arm is provided, the first end of which is rotatably connected to the support wheel, and the support wheel arm is connected to the outer gantry via a first pivot. The lever assembly includes an active member and a connecting block, the first end of which is connected to the active member, the second end of which is connected to the outer gantry via a second pivot, and the third end of which is rotatably connected to the second end of the support wheel arm. The first pivot is disposed between the first and second ends of the support wheel arm. The active member can move along the height direction of the outer gantry to drive the connecting block to rotate about the second pivot, and drive the support wheel arm to rotate about the first pivot, so that the support wheel can rotate relative to the outer gantry.

[0007] In some embodiments, the active element is configured as a push rod, one end of which is connected to the outer gantry and the other end of which is connected to the first end of the connecting block.

[0008] In some embodiments, the active element is configured as a movable bearing connected to the first end of the connecting block, and the movable bearing can move along the height direction of the outer gantry to drive the connecting block to rotate about the second rotating axis as the rotation center, and drive the support wheel arm to rotate about the first rotating axis as the rotation center, so that the support wheel can rotate relative to the outer gantry.

[0009] In some embodiments, the chassis assembly further includes a bearing support plate and a chassis base plate, and a motion track extending along the length direction of the outer gantry is formed between the bearing support plate and the chassis base plate. The movable bearing is disposed in the motion track and can move along the length direction and the height direction of the outer gantry.

[0010] In some embodiments, the bearing support plate has a first contact surface and a second contact surface on the side facing the movable bearing, the second contact surface protruding from the first contact surface; the chassis base plate has a third contact surface and a fourth contact surface on the side facing the movable bearing, the third contact surface protruding from the fourth contact surface.

[0011] In some embodiments, the lever assembly further includes a first lever disposed along the length of the outer gantry, a first end of the first lever being connected to a third end of the connecting block via a third pivot, and a second end of the first lever being adapted to be connected to the support wheel arm via a fourth pivot.

[0012] In some embodiments, the length of the first lever is adjustable.

[0013] In some embodiments, the first lever is a split type, comprising at least two connected sub-rods, the two sub-rods being screwed together.

[0014] In some embodiments, the system further includes a drive assembly connected to the gantry assembly and used at least to drive the outer gantry to extend or retract relative to the chassis assembly; a timing pulley assembly, the input end of which is connected to the power output end of the drive assembly; the timing pulley assembly includes a toothed timing belt, a timing pulley, a first idler pulley, a second idler pulley, and a third idler pulley, the timing pulley being configured as the input end of the timing pulley assembly, the toothed timing belt being wound around the timing pulley, the first idler pulley, the second idler pulley, and the third idler pulley, and the two ends of the toothed timing belt being respectively connected to the two ends of the chassis assembly along the length direction of the chassis assembly; wherein, the third idler pulley is used to increase the contact area between the toothed timing belt and the timing pulley.

[0015] According to the forklift of the present invention, the support wheel on the outer mast can be driven to rotate relative to the outer mast under the action of the lever assembly, so that the support wheel will not tilt forward or backward when it touches the ground during the operation of the mast assembly, thus ensuring stability and safety during the process of picking up goods. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a forklift according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of a gantry assembly according to an embodiment of the present invention;

[0019] Figure 3 This is a side view of a gantry assembly according to an embodiment of the present invention;

[0020] Figure 4 This is a partial schematic diagram of a gantry assembly according to an embodiment of the present invention;

[0021] Figure 5 This utility model Figure 4 Enlarged view of point A.

[0022] Figure Labels

[0023] 1-Mast assembly; 11-Forks; 12-Lever assembly; 121-Drive component; 122-Connecting block; 123-First lever; 1231-Sub-lever; 13-Outer mast; 131-Support wheel; 132-Support wheel arm; 2-Chassis assembly; 21-Bearing support plate; 211-First contact surface; 212-Second contact surface; 22-Chassis base plate; 221-Third contact surface; 222-Fourth contact surface; 23-Motion track; 3-Toothed synchronous belt; 4-Synchronous belt pulley; 5-First idler pulley; 6-Second idler pulley; 7-Third idler pulley. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0025] In the description of this utility model, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or relative positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Unless otherwise specified, the above-mentioned orientational descriptions can be flexibly set in actual application, provided that the relative positional relationship shown in the accompanying drawings is satisfied.

[0026] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "communication" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a direct connection or an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] In embodiments of this invention, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, article, or apparatus that includes that element.

[0029] In this embodiment of the invention, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in this embodiment of the invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0030] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0031] Forklifts are core material handling equipment in industrial and logistics scenarios. Their core function is to solve tasks that are difficult for humans to perform efficiently, such as loading, unloading, moving, and stacking heavy objects, while optimizing space utilization and ensuring operational safety. With further technological advancements, a new type of forklift—the AGV (Automated Guided Vehicle)—has emerged. Equipped with an automated guidance system, this intelligent material handling equipment can replace manual labor in warehouses, workshops, and other scenarios, automatically loading, unloading, moving, and stacking materials, achieving unmanned and efficient warehousing and logistics. However, both traditional forklifts and AGVs suffer from the problem of the mast assembly tilting forward and backward during the lifting process, which can easily cause instability. This invention aims to propose a new technical solution to address these issues.

[0032] The following is for reference. Figures 1-5 This invention describes a forklift according to an embodiment of the present invention.

[0033] An embodiment of the first aspect of this utility model provides a forklift, which includes: a mast assembly 1, the mast assembly 1 including an outer mast 13 and a lever assembly 12; a chassis assembly 2, the mast assembly 1 being connected to the chassis assembly 2, wherein the outer mast 13 can extend or retract relative to the chassis assembly 2; a support wheel 131 is provided at the front end of the outer mast 13, the support wheel 131 is connected to the lever assembly 12, and under the drive of the lever assembly 12, the support wheel 131 can rotate relative to the outer mast 13.

[0034] Specifically, such as Figure 1 and Figure 3As shown, the forklift includes a mast assembly 1 and a chassis assembly 2. The mast assembly 1 includes an outer mast 13 and a lever assembly 12. A support wheel 131 is located at the front end of the outer mast 13, and the support wheel 131 is connected to the lever assembly 12. Under the drive of the lever assembly 12, the support wheel 131 can rotate relative to the outer mast 13. During forklift operation, when the mast assembly 1 moves along the pallet structure on the chassis assembly 2, the pallet ends are often equipped with ramp structures to guide the rollers of the mast assembly 1 up and down. When reaching the target working position, the forks 11 are used to pick up the goods. In traditional structures, the bottom of the mast assembly 1 is supported only by rollers. When the rollers enter the ramp section on the pallet from the horizontal section, due to the sudden change in the stress point, the mast assembly 1 is prone to tilting forward or backward, causing the center of gravity of the outer mast 13 to shift, the goods to sway or even slip, seriously threatening operational safety. This embodiment features a support wheel 131 at the front end of the outer mast 13, which rotates with the lever assembly 12. When the mast assembly 1 enters the ramp, the support wheel 131 automatically presses down to contact the pallet ramp surface until it touches the ground, forming a third support point. This, together with the rear roller, constitutes a three-point support system. When the mast assembly 1 moves forward to the descending section of the ramp, the support wheel 131, under the movement of the pallet lever assembly 12, rotates downward and conforms to the ramp, counteracting the forward tilting tendency of the mast assembly 1. When the mast assembly 1 retreats from the ramp section back to the horizontal section, the support wheel 131 remains in contact with the pallet ramp surface under the reset action of the lever assembly 12 until it returns to its original position. This structure achieves dynamic horizontal maintenance of the mast assembly 1 throughout the entire pallet movement, significantly improving stability and safety during forklift and handling processes.

[0035] In some embodiments, a support wheel arm 132 is provided, with its first end rotatably connected to a support wheel 131. The support wheel arm 132 is connected to the outer gantry 13 via a first pivot. The lever assembly 12 includes an active member 121 and a connecting block 122. The first end of the connecting block 122 is connected to the active member 121, and the second end of the connecting block 122 is connected to the outer gantry 13 of the gantry assembly 1 via a second pivot. The third end of the connecting block 122 is rotatably connected to the second end of the support wheel arm 132. The first pivot is disposed between the first and second ends of the support wheel arm 132. The active member 121 can move along the height direction of the outer gantry 13 to drive the connecting block 122 to rotate around the second pivot, thereby driving the support wheel arm 132 to rotate around the first pivot, so that the support wheel 131 can rotate relative to the outer gantry 13.

[0036] Specifically, such as Figure 3As shown, the first end of the support wheel arm 132 is rotatably connected to the support wheel 131, and the support wheel arm 132 is connected to the outer gantry 13 via a first rotating shaft. The lever assembly 12 includes an active member 121 and a connecting block 122. The first end of the connecting block 122 is connected to the active member 121, and the second end of the connecting block 122 is connected to the outer gantry 13 of the gantry assembly 1 via a second rotating shaft. The third end of the connecting block 122 is rotatably connected to the second end of the support wheel arm 132. The first rotating shaft is located between the first and second ends of the support wheel arm 132. The active member 121 can move along the height direction of the outer gantry 13 to drive the connecting block 122 to rotate around the second rotating shaft as the rotation center, thereby driving the support wheel arm 132 to rotate around the first rotating shaft as the rotation center, so that the support wheel 131 can rotate relative to the outer gantry 13. The support wheel arm 132 is a rigid linkage structure, and its length and position relative to the first rotating shaft have been mechanically optimized to ensure that the torque transmission path is the shortest and the deformation is minimal when the support wheel 131 contacts the slope. The connecting block 122 has a "Y"-shaped structure, with its second end hinged to the outer mast 13 via a second pivot, serving as a fixed fulcrum for the lever assembly 12. When the driving member 121 moves along the height direction of the outer mast 13 (i.e., perpendicular to the forklift's forward direction), the connecting block 122 rotates around the second pivot, thereby causing the support wheel arm 132 to swing around the first pivot, achieving the lifting and lowering action of the support wheel 131. This structure converts the linear motion of the driving member 121 into the arc motion of the support wheel 131, providing sensitive response and precise control. It requires no additional sensors or electronic control systems, relying entirely on mechanical linkage to achieve adaptive adjustment.

[0037] In some embodiments, the active member 121 is configured as a push rod, one end of which is connected to the outer gantry 13 and the other end of which is connected to the first end of the connecting block 122.

[0038] Specifically, the driving component 121 is constructed as a push rod, with one end connected to the outer mast 13 and the other end connected to the first end of the connecting block 122. The push rod can be, but is not limited to, made of alloy steel, and its two ends are fixed to the outer mast 13 and the connecting block 122 respectively. When the outer mast 13 extends, the push rod is pushed by the drive mechanism, causing the connecting block 122 to rotate counterclockwise, thus pressing down the support wheel 131. When the outer mast 13 retracts, the push rod is pushed back by the drive mechanism, and the support wheel 131 returns to its original position under the action of the push rod. This structure is simple, low-cost, and highly reliable, and is suitable for various electric or internal combustion forklift platforms.

[0039] In some embodiments, the active member 121 is configured as a movable bearing, which is connected to the first end of the connecting block 122 and can move along the height direction of the outer gantry 13 to drive the connecting block 122 to rotate around the second pivot axis, thereby driving the support wheel arm 132 to rotate around the first pivot axis, so that the support wheel 131 can rotate relative to the outer gantry 13.

[0040] Specifically, such as Figure 3 , Figure 4 and Figure 5 As shown, the driving element 121 is constructed as a movable bearing, which is connected to the first end of the connecting block 122. The movable bearing can move along the height direction of the outer mast 13 to drive the connecting block 122 to rotate around the second pivot, thereby driving the support wheel arm 132 to rotate around the first pivot, so that the support wheel 131 can rotate relative to the outer mast 13. The movable bearing can be, but is not limited to, a ball bearing or a roller bearing, and is fixedly connected to the connecting block 122 and embedded in the motion track 23. This structure is suitable for intelligent forklift systems that require precise control of the timing of the support wheel 131's movement.

[0041] In some embodiments, the chassis assembly 2 further includes a bearing support plate 21 and a chassis base plate 22. A motion track 23 extending along the length direction of the outer gantry 13 is formed between the bearing support plate 21 and the chassis base plate 22. A movable bearing is disposed in the motion track 23 and can move along the length direction of the outer gantry 13 and the height direction of the outer gantry 13.

[0042] Specifically, such as Figure 3 and Figure 5 As shown, the chassis assembly 2 also includes a bearing support plate 21 and a chassis base plate 22. A motion track 23 extending along the direction of the outer mast 13 is formed between the bearing support plate 21 and the chassis base plate 22. The movable bearing in the above embodiment is disposed in the motion track 23 and can move along the length direction and the height direction of the outer mast 13. The motion track 23 is composed of two parallel guide grooves, in which the movable bearing is limited and slides, so that the entire mast assembly 1 is always in the center position of the pallet assembly, preventing the mast assembly 1 from moving left and right and affecting the running stability of the vehicle. This dual-degree-of-freedom design allows the movable bearing to maintain a stable connection with the connecting block 122 during the lifting or tilting of the mast assembly 1, avoiding jamming or stress concentration.

[0043] In some embodiments, the bearing support plate 21 is provided with a first contact surface 211 and a second contact surface 212 on the side facing the movable bearing, and the second contact surface 212 protrudes from the first contact surface 211; the chassis base plate 22 is provided with a third contact surface 221 and a fourth contact surface 222 on the side facing the movable bearing, and the third contact surface 221 protrudes from the fourth contact surface 222.

[0044] Specifically, such as Figure 5As shown, the bearing support plate 21 has a first contact surface 211 and a second contact surface 212 on the side facing the movable bearing, with the second contact surface 212 protruding from the first contact surface 211; the chassis base plate 22 has a third contact surface 221 and a fourth contact surface 222 on the side facing the movable bearing, with the third contact surface 221 protruding from the fourth contact surface 222. The first contact surface 211 and the third contact surface 221 form a first horizontal guide section, and the second contact surface 212 and the fourth contact surface 222 form a second horizontal guide section. The height of the first horizontal guide section is higher than that of the second horizontal guide section, and they are connected by an inclined plane. The inclination angle of the inclined plane matches the inclination angle of the ramp structure of the pallet. When the gantry assembly 1 extends, the movable bearing slides from the first horizontal guide section to the inclined plane, and then to the second horizontal guide section, generating a displacement component along the height direction of the outer gantry 13, thereby triggering the connecting block 122 to rotate, realizing the automatic rotation of the support wheel 131. This structure realizes a mechanical "slope sensing-response" closed loop without external control.

[0045] In some embodiments, the lever assembly 12 further includes a first lever 123, which is arranged along the length of the outer gantry 13. The first end of the first lever 123 is connected to the third end of the connecting block 122 via a third pivot, and the second end of the first lever 123 is adapted to be connected to the outer gantry 13 support arm 132 via a fourth pivot.

[0046] Specifically, such as Figure 3 As shown, the lever assembly 12 also includes a first lever 123, which is arranged along the length of the outer gantry 13. The first end of the first lever 123 is connected to the third end of the connecting block 122 via a third pivot, and the second end of the first lever 123 is adapted to be connected to the support arm 132 of the outer gantry 13 via a fourth pivot. The first lever 123, as an intermediate transmission component, extends the lever arm length, allowing the small rotation of the connecting block 122 to be converted into a large-angle swing of the support arm 132, thus improving the mechanism's sensitivity. Its length direction is arranged parallel to the outer gantry 13, avoiding interference with other components and resulting in a compact structure.

[0047] In some embodiments, the length of the first lever 123 is adjustable.

[0048] Specifically, the length of the first lever 123 is adjustable, and it can be, but is not limited to, a lead screw or other length-adjustable structure. By adjusting the total length of the first lever 123, the lifting amplitude and response curve of the support wheel 131 can be changed, solving the tolerance problem during assembly. At the same time, it can also adapt to the needs of pallet ramps of different heights or center of gravity changes under different load conditions, realizing the modular adaptation of the mechanism.

[0049] In some embodiments, the first lever 123 is a split type, comprising at least two connected sub-rods 1231, which are screwed together.

[0050] Specifically, such as Figure 3 As shown, the first lever 123 is a split type, comprising at least two connected sub-rods 1231, which are screwed together. The sub-rods 1231 are made of alloy structural steel, and the screwed connection part is equipped with scale marks and a locking nut. Maintenance personnel can freely adjust the length to achieve rapid on-site calibration. By adjusting the number and length of the sub-rods 1231 of the first lever 123, the lifting amplitude and response curve of the support wheel 131 can be changed, solving the tolerance problem during assembly. At the same time, it can also adapt to the needs of pallet ramps of different heights or center of gravity changes under different load conditions, realizing the modular adaptation of the mechanism.

[0051] In some embodiments, the forklift further includes a drive assembly connected to the mast assembly 1, at least for driving the outer mast 13 to extend or retract relative to the chassis assembly 2; a timing pulley assembly, the input end of which is connected to the power output end of the drive assembly; the timing pulley assembly includes a toothed timing belt 3, a timing pulley 4, a first idler pulley 5, a second idler pulley 6, and a third idler pulley 7, the timing pulley 4 being configured as the input end of the timing pulley assembly, the toothed timing belt 3 being wound around the timing pulley 4, the first idler pulley 5, the second idler pulley 6, and the third idler pulley 7, and the two ends of the toothed timing belt 3 being respectively connected to the two ends of the chassis assembly 2 along the length direction of the outer mast 13; wherein, the third idler pulley 7 is used to increase the contact area between the toothed timing belt 3 and the timing pulley 4.

[0052] Specifically, in traditional forklifts, synchronous belt drives achieve tension and transmission through only two or three gears, resulting in a small wrap angle, easy slippage, and rapid wear. For example... Figure 2 and Figure 4 As shown, in this embodiment, a third idler pulley 7 is added between the synchronous pulley 4, the first idler pulley 5, and the second idler pulley 6, so that the toothed synchronous belt 3 forms an "Ω" shaped winding path, increasing the contact area between the toothed synchronous belt 3 and the synchronous pulley 4. Under a rated load of 1 ton, this structure extends the life of the synchronous belt to 2.3 times that of the original structure, and the transmission efficiency remains stable at over 96%, with no significant slippage or abnormal noise. Furthermore, the third idler pulley 7 can be, but is not limited to, a lightweight alloy wheel with bearings, fixed to the outer frame 13.

[0053] It is understood that the forklift referred to in this utility model may be, but is not limited to, a traditional forklift or an AGV forklift. According to the embodiments of this utility model, the support wheel 131 on the outer mast 13 can rotate relative to the outer mast 13 under the action of the lever assembly 12, so that when the support wheel 131 touches the ground during the operation of the mast assembly 1, it will not tilt forward or backward, ensuring stability and safety during the picking of goods.

[0054] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0055] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A forklift, characterized in that, The forklift includes: A gantry assembly, the gantry assembly including an outer gantry and a lever assembly; A chassis assembly, wherein the gantry assembly is connected to the chassis assembly, and the outer gantry can extend or retract relative to the chassis assembly; The front end of the outer gantry is provided with a support wheel, which is connected to the lever assembly. Under the drive of the lever assembly, the support wheel can rotate relative to the outer gantry.

2. The forklift according to claim 1, characterized in that, include: A support wheel arm, the first end of which is rotatably connected to the support wheel, and the support wheel arm is connected to the outer gantry via a first pivot. The lever assembly includes an active component and a connecting block. A first end of the connecting block is connected to the active component, a second end of the connecting block is connected to the outer gantry via a second pivot, and a third end of the connecting block is rotatably connected to the second end of the support wheel arm. The first pivot is disposed between the first end and the second end of the support wheel arm. The active component can move along the height direction of the outer gantry to drive the connecting block to rotate around the second rotating shaft as the rotation center, and drive the support wheel arm to rotate around the first rotating shaft as the rotation center, so that the support wheel can rotate relative to the outer gantry.

3. The forklift according to claim 2, characterized in that, The active component is configured as a push rod, one end of which is connected to the outer gantry, and the other end of which is connected to the first end of the connecting block.

4. The forklift according to claim 2, characterized in that, The active component is configured as a movable bearing, which is connected to the first end of the connecting block. The movable bearing can move along the height direction of the outer gantry to drive the connecting block to rotate around the second rotating shaft as the rotation center, and drive the support wheel arm to rotate around the first rotating shaft as the rotation center, so that the support wheel can rotate relative to the outer gantry.

5. The forklift according to claim 4, characterized in that, The chassis assembly also includes a bearing support plate and a chassis base plate. A motion track extending along the length direction of the outer gantry is formed between the bearing support plate and the chassis base plate. The movable bearing is disposed in the motion track and can move along the length direction and the height direction of the outer gantry.

6. The forklift according to claim 5, characterized in that, The bearing support plate has a first contact surface and a second contact surface on the side facing the movable bearing, with the second contact surface protruding from the first contact surface; the chassis base plate has a third contact surface and a fourth contact surface on the side facing the movable bearing, with the third contact surface protruding from the fourth contact surface.

7. The forklift according to claim 2, characterized in that, The lever assembly further includes a first lever, which is arranged along the length of the outer gantry. The first end of the first lever is connected to the third end of the connecting block via a third pivot, and the second end of the first lever is adapted to be connected to the support wheel arm via a fourth pivot.

8. The forklift according to claim 7, characterized in that, The length of the first lever is adjustable.

9. The forklift according to claim 8, characterized in that, The first lever is a split type, comprising at least two connected sub-rods, which are screwed together.

10. The forklift according to any one of claims 1-9, characterized in that, The forklift also includes: A drive assembly connected to the gantry assembly, at least for driving the outer gantry to extend or retract relative to the chassis assembly; A synchronous pulley assembly, the input end of which is connected to the power output end of a drive assembly; the synchronous pulley assembly includes a toothed synchronous belt, a synchronous pulley, a first idler pulley, a second idler pulley, and a third idler pulley, the synchronous pulley being configured as the input end of the synchronous pulley assembly, the toothed synchronous belt being wound around the synchronous pulley, the first idler pulley, the second idler pulley, and the third idler pulley, and the two ends of the toothed synchronous belt being respectively connected to the two ends of the chassis assembly along the length direction of the chassis assembly; wherein, the third idler pulley is used to increase the contact area between the toothed synchronous belt and the synchronous pulley.

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