A station driver type electric truck and its lifting mechanism

Abstract

The application relates to a station driving type electric forklift truck and a lifting mechanism thereof, wherein the lifting mechanism comprises a frame, a fork mechanism, a lifting oil cylinder configured to drive the fork mechanism to move up and down relative to the frame, the lifting oil cylinder has an adjusting angle inclined in a vertical direction, a connecting rod mechanism comprising a swing rod and a long connecting rod, a first hinged end of the swing rod is hinged to the frame, a second hinged end of the swing rod is hinged to a fork frame, a third hinged end of the swing rod is hinged to one end of the long connecting rod, and when the fork mechanism moves up and down, the fork frame drives the swing rod to push or pull the long connecting rod, so that a load wheel assembly at a front end of the long connecting rod is switched between a first state and a second state. According to the scheme, a group of driving mechanisms are used to control the fork lifting and drive the front load wheel group of the fork to stretch out or retract at the same time, and the production and control are simple.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of stand-steer type trolleys, and in particular to a stand-steer type trolley and a lifting mechanism thereof. BACKGROUND

[0002] The stand-steer type electric trolley is provided with driving assembly for driving power and hydraulic unit for lifting power, and the lifting cylinder is used to lift or lower the fork frame to realize the transportation of goods. At present, most stand-steer type electric trolleys use pull rod lifting mechanisms, which have complex structures and high manufacturing costs, and the corresponding use cost is also high.

[0003] The patent application with the publication number CN117658023A discloses a trolley for double-sided pallet transportation, in which one end of the pull rod is connected with the front load wheel group of the fork, the other end of the pull rod is provided with a roller, and a multi-section roller inclined surface is arranged on the frame. When the telescopic mechanism drives the vertical lifting of the fork upright plate, the roller on the pull rod moves along the multi-section roller inclined surface to drive the telescopic pull rod, thereby driving the front load wheel group at one end of the pull rod to extend or retract.

[0004] In the above-mentioned scheme, the shape and inclination of each section of the multi-section roller inclined surface need to be calculated in advance, and a large amount of fitting calculation is required during the production stage. In addition, the shape and inclination of each section of the inclined surface need to be strictly processed according to the calculation during manufacturing, and the precision requirement during the production stage is high. At the same time, according to the specification and drawings disclosed by CN117658023A, it is known that no manual driving operation mechanism is provided, and therefore it can be determined that the trolley involved is an AGV vehicle. The precision requirement of the AGV vehicle is high, and specifically, since the AGV vehicle needs to be positioned by the sensor arranged at the front end of the fork, the fork needs to maintain the same position in the horizontal direction during the lifting process, and therefore the precision requirement of the multi-section roller inclined surface is high.

[0005] The patent application with the publication number CN116374893A and the utility model patent with the publication number CN219117088U both use two independent driving mechanisms to drive the lifting of the fork and the extension or retraction of the front load wheel group of the fork. Although the manufacturing is simple, the increase of the hydraulic system increases the production cost and the complexity of the control system of the trolley. SUMMARY

[0006] In order to solve the above-mentioned problems, the purpose of the present application is to provide a stand-steer type trolley and a lifting mechanism thereof, which controls the lifting of the fork and the extension or retraction of the front load wheel group of the fork by one driving mechanism, and does not need to additionally provide a multi-section roller inclined surface.

[0007] In a first aspect, the present application provides a lifting mechanism of a stand-steer type electric trolley, comprising:

[0008] Frame

[0009] Fork mechanism, having a stroke of up and down movement relative to the frame, the fork mechanism comprising a fork frame and forks mounted on the fork frame;

[0010] Lifting cylinder, configured to drive the fork mechanism to move up and down relative to the frame, the lifting cylinder having an adjustment angle in the vertical direction;

[0011] Linkage mechanism, comprising a swing rod and a long link, the swing rod having three hinged ends, the relative positions of the three hinged ends on the swing rod always remain fixed; the first hinged end of the swing rod is hinged with the frame, the second hinged end of the swing rod is hinged with the fork frame, and the third hinged end of the swing rod is hinged with one end of the long link; while the fork mechanism moves up and down, the second hinged end rotates around the first hinged end, driving the third hinged end to drive the long link to move in the horizontal direction; within the stroke of the fork mechanism moving up and down relative to the frame, the angle of inclination of the fork frame in the vertical direction caused by the circular motion of the second hinged end around the first hinged end is adapted to the adjustment angle of the lifting cylinder in the vertical direction;

[0012] Load wheel assembly, corresponding to the fork, the load wheel assembly having a first state and a second state, in the first state the load wheel assembly is retracted under the lower part of the fork, and in the second state the load wheel assembly extends downward from the lower part of the fork; the load wheel assembly comprises a wheel frame and load wheels mounted on the wheel frame, the wheel frame having a first hinged point and a second hinged point, the wheel frame being hinged with the fork at the first hinged point, and the second hinged point of the wheel frame being hinged with the other end of the long link.

[0013] In a second aspect, the application provides a stand-steer electric pallet truck having the lifting mechanism of the above-mentioned stand-steer electric pallet truck.

[0014] By using the above-mentioned scheme, the fork frame and the long link are connected by the swing rod, so that when the lifting cylinder drives the fork mechanism to rise and fall, the fork frame drives the long link to extend and retract through the swing rod, causing the load wheel assembly to switch between the first state and the second state, without the need for an additional driving mechanism to drive the long link to move. Moreover, the stand-steer electric pallet truck has a lower precision requirement than an AGV vehicle, so even if the fork mechanism tilts slightly forward and backward relative to the frame during the lifting process due to the swing rod, it will not affect the normal use of the pallet truck. By using the above-mentioned lifting mechanism in which the lifting cylinder cooperates with the linkage mechanism, there is no need to set a special slope for the multi-section roller slope, and the production and control are simple. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 Structure diagram of the load wheel in the second state (partially cutaway view of the pallet truck) for lifting the fork mechanism;

[0016] Figure 2 Structure diagram of the load wheel assembly in the second state (partially cutaway view of the truck);

[0017] Figure 3 Structure diagram of the load wheel assembly in the second state (partially cutaway view of the truck);

[0018] Figure 4 Structure diagram of the load wheel assembly in the second state (partially cutaway view of the truck);

[0019] Figure 5 Structure diagram of the load wheel assembly in the second state (partially cutaway view of the truck);

[0020] Figure 6 Structure diagram of the load wheel assembly in the second state (partially cutaway view of the truck);

[0021] Figure 7 Structure diagram of the load wheel assembly in the second state (partially cutaway view of the truck);

[0022] Figure 8 Structure diagram of the load wheel assembly in the second state (partially cutaway view of the truck).

[0023] Reference signs:

[0024] Frame 1, guide rail 11, first connecting seat 12, first limiting bolt 121,

[0025] Fork frame 21, guide wheel 211, fork 22, second connecting seat 23, second limiting bolt 231,

[0026] Lifting cylinder 3, cylinder body 31, connecting end 311, telescopic rod 32, telescopic end 321, ball 33,

[0027] Swing rod 41, first hinged end 411, second hinged end 412, third hinged end 413, long connecting rod 42,

[0028] Load wheel assembly 5, wheel frame 51, first hinged point 511, second hinged point 512, load wheel 52. DETAILED DESCRIPTION

[0029] Embodiments of the present application will be described in detail below.

[0030] This embodiment relates to a stand-steer electric truck, which has a lifting mechanism. As shown in Figures 1-2As shown, the lifting mechanism of the station driver type electric pallet truck comprises a vehicle frame 1; a fork mechanism having a stroke of up and down movement relative to the vehicle frame 1, the fork mechanism comprising a fork frame 21 and a fork 22 mounted on the fork frame 21, in this embodiment, the fork 22 is fixedly welded with the fork frame 21 as a whole; a lifting oil cylinder 3 configured to drive the fork mechanism to move up and down relative to the vehicle frame 1, the lifting oil cylinder 3 has an adjustment angle inclined in the vertical direction; a connecting rod mechanism comprising a swing rod 41 and a long connecting rod 42, the swing rod 41 has three hinged ends, the relative positions of the three hinged ends on the swing rod 41 always remain fixed; the first hinged end 411 of the swing rod 41 is hinged with the vehicle frame 1, the second hinged end 412 of the swing rod 41 is hinged with the fork frame 21, and the third hinged end 413 of the swing rod 41 is hinged with one end of the long connecting rod 42; while the fork mechanism moves up and down, the second hinged end 412 rotates around the first hinged end 411 as the center to drive the third hinged end 413 to drive the long connecting rod 42 to move in the horizontal direction; within the stroke of the fork mechanism moving up and down relative to the vehicle frame 1, the inclination angle of the fork frame 21 in the vertical direction caused by the circular motion of the second hinged end 412 around the first hinged end 411 as the center is matched with the adjustment angle of the lifting oil cylinder 3 in the vertical direction; a load wheel assembly 5 corresponding to the fork, the load wheel assembly 5 has a first state and a second state, in the first state, the load wheel assembly 5 is retracted under the lower part of the fork, and in the second state, the load wheel assembly 5 extends downward from the lower part of the fork; the load wheel assembly 5 comprises a wheel frame 51 and a load wheel 52 mounted on the wheel frame 51, the wheel frame 51 has a first hinged point 511 and a second hinged point 512, the wheel frame 51 is hinged with the fork at the first hinged point 511, and the second hinged point 512 of the wheel frame 51 is hinged with the other end of the long connecting rod 42.

[0031] The above lifting mechanism connects the fork frame 21 and the long connecting rod 42 through the swing rod 41, so that while the lifting oil cylinder 3 drives the fork mechanism to rise and fall, the fork frame 21 drives the long connecting rod 42 to extend and retract through the swing rod 41 to switch the load wheel assembly 5 between the first state and the second state, without the need to additionally set a driving mechanism to drive the long connecting rod 42 to act. Due to the setting of the swing rod 41, the fork mechanism will have a small angle of front and back tilt relative to the vehicle frame 1 during the lifting process, and the lifting oil cylinder 3 has an adjustment angle inclined in the vertical direction, which can be adjusted synchronously with the change of the position of the second hinged end 412 of the swing rod 41 in the front and back directions relative to the vehicle frame 1 during the lifting process, to prevent damage to the lifting oil cylinder 3 due to the change of the tilt angle of the fork mechanism relative to the vehicle frame 1 during the lifting process.

[0032] The load wheel assembly 5 in this embodiment can directly adopt the structure of the fork front load wheel group disclosed in CN117658023A.

[0033] In combination Figure 3The embodiment is provided with a hinge shaft at a position corresponding to the fork on the fork frame 21, and the second hinge end 412 of the swing lever 41 is connected at the hinge shaft, so that the linkage of the fork frame 21 and the linkage mechanism can be realized.

[0034] In combination Figure 3 And Figure 4 The frame 1 is provided with a plurality of guide rails 11 extending in the vertical direction, and the fork frame 21 is provided with a plurality of guide wheels 211, which are in sliding connection with the guide rails 11, and one guide rail 11 is connected with only one guide wheel 211. The vertical guidance of the fork mechanism during the up-down lifting process is realized by the cooperation of the guide rails 11 and the guide wheels 211, and since the fork mechanism will exist a small angle of front-back tilting relative to the frame 1 during the lifting process, the sliding connection of one guide rail 11 with only one guide wheel 211 is limited, and the rotation axis of the guide wheel 211 is perpendicular to the tilting direction of the fork mechanism, so that the small angle of front-back tilting of the fork mechanism relative to the frame 1 is avoided due to the setting of the guide rail 11 and the guide wheel 211, and the linkage of the fork frame 21 and the linkage mechanism can be realized normally.

[0035] The lifting oil cylinder 3 includes a cylinder body 31 and a telescopic rod 32, and the end opposite to the telescopic end 321 of the telescopic rod 32 of the cylinder body 31 is a connecting end 311. One of the connecting end 311 of the cylinder body 31 and the telescopic end 321 of the telescopic rod 32 is connected with the frame 1, and the other is connected with the fork frame 21. The lifting oil cylinder 3 connects the frame 1 and the fork frame 21, so that the up-down movement of the fork mechanism relative to the frame 1 can be realized by the telescopic driving of the telescopic rod 32 of the lifting oil cylinder 3. Figure 5 As shown in the figure, the connecting part of the connecting end 311 of the cylinder body 31 and the telescopic end 321 of the telescopic rod 32 is connected with the frame 1 or the fork frame 21 through a spherical surface structure. The spherical surface structure in the application can be a partial spherical surface, i.e. an arc surface, or a complete spherical surface, i.e. a spherical surface. The spherical surface structure is provided to realize the adjustment angle of the lifting oil cylinder 3 in the vertical direction. When the fork mechanism tilts forward and backward at a small angle relative to the frame 1 during the lifting process, the lifting oil cylinder 3 can be tilted synchronously to avoid damage to the lifting oil cylinder 3. In the specific embodiment, the connecting end 311 of the cylinder body 31 is provided with a ball head structure. The ball head structure can be a structure independent of the cylinder body 31, and is connected with the cylinder body 31 through a connecting member such as a screw rod on the ball head structure. In this way, the connecting structure of the connecting part between the ball head structure and the cylinder body 31 is weak. Alternatively, the ball head structure can be directly formed on the connecting end 311 of the cylinder body 31, but the ball head structure needs to be heat treated to ensure the strength of the connecting end 311, which has an impact on the processing cost. As a preferred embodiment, Figures 5-8As shown, the connecting end 311 of the cylinder body 31 has a concave spherical surface, which is in rolling contact with the ball bearing 33. Since the ball bearing 33 itself has undergone heat treatment, the cylinder body 31 and the ball bearing 33 are only connected through the arc-shaped surface, which does not require additional strengthening treatment of the cylinder body 31, and the setting method is simple.

[0036] like Figures 6-8 As shown, the system includes a first connecting seat 12 and a second connecting seat 23. A first slot is formed on the first connecting seat 12, and the ball bearing 33 of the connecting end 311 of the cylinder body 31 is located within the first slot. A tilting gap exists between the outer wall of the connecting end 311 of the cylinder body 31 and the inner wall of the first slot. A second slot is formed on the second connecting seat 23, and the telescopic end 321 of the telescopic rod 32 is located within the second connecting seat 23. A tilting gap exists between the outer wall of the telescopic end 321 and the inner wall of the second slot. Due to the tilting gap, the lifting cylinder can tilt. The first connecting seat 12 is mounted on the frame 1, and the second connecting seat 23 is mounted on the fork carriage 21. Therefore, in this embodiment, the cylinder body 31 is connected to the frame 1, and the telescopic rod 32 is connected to the lifting cylinder 3. Preferably, the first connecting seat 12 is detachably connected to the frame 1. During assembly, the second connecting seat 23 is first fixed to the fork carriage 21. The ball bearing 33 is placed in the first slot of the first connecting seat 12, and the telescopic end 321 of the telescopic rod 32 of the lifting cylinder is inserted into the second slot. Then, the first slot is connected to the connecting end 311 of the cylinder from the bottom, and the first connecting seat 12 is fixed to the frame 1. With the above structure, the assembly of the lifting cylinder is simple.

[0037] The connecting end 311 of the cylinder body 31 has a radial dimension change in the axial direction, forming a first limiting step. A first limiting bolt 121, one end of which extends into the first slot, is connected to the first slot. The first limiting step and the first limiting bolt 121 cooperate to hold the connecting end 311 within the first slot. The telescopic end 321 of the telescopic rod 32 has a radial dimension change in the axial direction, forming a second limiting step. A second limiting bolt 231, one end of which extends into the second slot, is connected to the second slot. The second limiting step and the second limiting bolt 231 cooperate to hold the telescopic end 321 within the second slot. After the lifting cylinder is assembled with the first connecting seat 12 and the second connecting seat 23, the first limiting bolt 121 and the second limiting bolt 231 are respectively inserted into the first slot and the second slot, cooperating with the limiting step to achieve their limiting function. It should be noted that after the first limiting bolt 121 is installed in place, there is a gap between its end and the side wall of the cylinder body 31, and after the second limiting bolt 231 is installed in place, there is a gap between its end and the side wall of the telescopic rod 32, so as to avoid the setting of the limiting bolts from hindering the tilting of the lifting cylinder.

[0038] In this embodiment, the swing rod 41 is an L-shaped plate, the first hinged end 411 of the swing rod 41 is located on the long arm of the swing rod 41, the second hinged end 412 of the swing rod 41 is located on the corner of the swing rod 41, and the third connecting end 311 of the swing rod 41 is located on the short arm of the swing rod 41. One end of the long connecting rod 42 connected with the swing rod 41 is provided with an adjusting screw, the adjusting screw is arranged along the length direction of the long connecting rod 42 and is directly connected with the long connecting rod 42 through threads. Thus, the position of the long connecting rod 42 can be adjusted through the adjusting screw, and the applicability of the connecting rod mechanism is improved.

[0039] In combination Figures 6-8 The movement process of this embodiment is described as follows. In the initial state, the load wheel assembly 5 is in the first state, and the fork mechanism is switched to the second state. When the fork mechanism is raised, the fork frame 21 drives the second hinged end 412 of the swing rod 41 connected thereto to move upward. Since the position of the first hinged end 411 of the swing rod 41 is fixed, the second hinged end 412 of the swing rod 41 makes a circular motion clockwise with the first hinged end 411 as the center. The third hinged end 413 is located below the second hinged end 412. During this process, the third hinged end 413 makes a circular motion clockwise with the second hinged end 412 as the center. The third hinged end 413 of the swing rod 41 drives the long connecting rod 42 to move toward the front end of the fork. The long connecting rod 42 drives the wheel frame 51 of the load wheel assembly 5 to rotate with the first hinged point 511 as the center of rotation, and drives the load wheels on the wheel frame 51 to extend downward. Similarly, when the fork mechanism is lowered, the fork frame 21 drives the second hinged end 412 of the swing rod 41 connected thereto to move downward. The second hinged end 412 of the swing rod 41 makes a circular motion counterclockwise with the first hinged end 411 as the center. The third hinged end 413 is located below the second hinged end 412. During this process, the third hinged end 413 makes a circular motion counterclockwise with the second hinged end 412 as the center. The third hinged end 413 of the swing rod 41 drives the long connecting rod 42 to move toward the rear end of the fork. The long connecting rod 42 drives the wheel frame 51 of the load wheel assembly 5 to rotate with the first hinged point 511 as the center of rotation, and drives the load wheels on the wheel frame 51 to retract upward.

[0040] This embodiment can switch the load wheel assembly 5 between the first state and the second state by driving the fork mechanism to rise and fall by the lifting oil cylinder 3 and driving the long connecting rod 42 to extend and retract by the fork frame 21 through the swing rod 41, without the need to additionally set a driving mechanism to drive the long connecting rod 42 to act. Moreover, the lifting oil cylinder 3 is set to be able to tilt within a small angle to adapt to the small inclination of the fork mechanism relative to the vehicle frame 1 during the lifting process of the fork mechanism.

[0041] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely divergences of the principles and application of the present application and that numerous modifications, changes, substitutions, and alterations can be made thereto without departing from the spirit and scope of the present application, which is defined by the following claims and their equivalents.

Claims

1. A lift mechanism for a rider-powered electric pallet truck, characterized in that The application relates to a truck, comprising: a truck frame; a fork mechanism having a stroke of up and down movement relative to the truck frame, the fork mechanism comprising a fork frame and forks mounted on the fork frame; a single lifting cylinder configured to drive the fork mechanism to move up and down relative to the truck frame, the lifting cylinder having an adjustment angle in the vertical direction; a linkage mechanism comprising a swing lever and a long linkage, the swing lever having three hinged ends, the relative positions of the three hinged ends on the swing lever being fixed at all times; the first hinged end of the swing lever is hinged to the truck frame, the second hinged end of the swing lever is hinged to the fork frame, and the third hinged end of the swing lever is hinged to one end of the long linkage; when the fork mechanism moves up and down, the second hinged end rotates around the first hinged end, driving the third hinged end to drive the long linkage to move in the horizontal direction; within the stroke of the fork mechanism moving up and down relative to the truck frame, the angle of inclination of the fork frame in the vertical direction caused by the circular motion of the second hinged end around the first hinged end is adapted to the adjustment angle of the lifting cylinder in the vertical direction; a load wheel assembly corresponding to the fork, the load wheel assembly having a first state and a second state, in the first state, the load wheel assembly is retracted under the lower part of the fork, and in the second state, the load wheel assembly extends downward from the lower part of the fork; the load wheel assembly comprises a wheel frame and load wheels mounted on the wheel frame, the wheel frame has a first hinged point and a second hinged point, the wheel frame is hinged to the fork at the first hinged point, and the second hinged point of the wheel frame is hinged to the other end of the long linkage; a pair of vertical guide rails are arranged on the truck frame, and a guide wheel corresponding to each guide rail is arranged on the fork frame, the guide wheel is in sliding connection with the guide rail, and one guide rail is connected with only one guide wheel, and the rotation axis of the guide wheel is perpendicular to the tilting direction of the fork mechanism; the lifting cylinder comprises a cylinder body and a telescopic rod, one end of the cylinder body opposite to the telescopic end of the telescopic rod is a connecting end, one of the connecting end of the cylinder body and the telescopic end of the telescopic rod is connected with the truck frame, and the other is connected with the fork frame; the connection between the connecting end of the cylinder body and the telescopic end of the telescopic rod is matched with the truck frame or the fork frame through a spherical surface structure.

2. A lift mechanism for a rider type electric lift truck according to claim 1 wherein, The connecting end of the cylinder body is provided with a ball head structure.

3. The lift mechanism of a sit-down electric pallet truck according to claim 1, wherein, The connecting end of the cylinder body is provided with an inner concave spherical surface, and the spherical surface is in rolling connection with a ball.

4. The lift mechanism of a sit-down electric pallet truck according to claim 3, characterized in that, The first connecting seat is detachably connected to the truck frame, and the second connecting seat is arranged on the fork frame.

5. The lift mechanism of a sit-down electric pallet truck according to claim 4, wherein The first connecting seat is detachably connected to the truck frame, and the second connecting seat is arranged on the fork frame.

6. A lift mechanism for a sit-down electric pallet truck according to claim 5, wherein The connecting end of the cylinder has a radial dimension change in the axial direction to form a first limiting step, a first limiting bolt with one end extending into the first slot is connected to the first slot, the first limiting step cooperates with the first limiting bolt to keep the connecting end in the first slot; the telescopic end of the telescopic rod has a radial dimension change in the axial direction to form a second limiting step, a second limiting bolt with one end extending into the second slot is connected to the second slot, the second limiting step cooperates with the second limiting bolt to keep the telescopic end in the second slot.

7. The lift mechanism of a sit-down electric pallet truck according to claim 1, wherein The swing rod is an L-shaped plate, the first hinged end of the swing rod is located on the long arm of the swing rod, the second hinged end of the swing rod is located on the corner part of the swing rod, and the third connecting end of the swing rod is located on the short arm of the swing rod.

8. The lift mechanism of a sit-down electric pallet truck according to claim 1, wherein, One end of the long connecting rod connected with the swing rod is provided with an adjusting screw rod, the adjusting screw rod is arranged along the length direction of the long connecting rod and is directly connected with the long connecting rod through threads.

9. A rider- steered electric pallet truck, characterized in that A lifting mechanism as claimed in any one of claims 1-8.

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