Tensioning device for forklift portal frame and forklift portal frame thereof

Abstract

The tensioning device is used for tensioning a front cylinder chain of the forklift gantry and comprises a front cylinder chain hanging plate arranged on the forklift gantry, the front cylinder chain hanging plate is provided with a hole penetrating through the upper end face and the lower end face, and a sleeve assembly is arranged on the end face, away from the front cylinder chain, of the front cylinder chain hanging plate; one end of the connector is connected with a front cylinder chain, and the other end of the connector penetrates into the sleeve assembly through the hole and is connected with the pull rod assembly; and through a first fastener arranged on the pull rod assembly, the pressing plate assembly is kept in contact with the sleeve assembly, and a limiting block in sliding connection with the pull rod assembly is arranged in the sleeve assembly. The front cylinder chain tensioning device is simple in structure, the tensioning device is additionally arranged, on the premise that an original portal frame structure is not changed, effective tensioning control over the front cylinder chain is achieved, the front cylinder chain tensioning device is suitable for existing equipment transformation and compatible with new product development, and transformation cost and assembly complexity are remarkably reduced.

Description

Technical Field

[0001] This utility model relates to the field of forklift mast technology, specifically a tensioning device for forklift masts and the forklift mast thereof. Background Technology

[0002] As a crucial component of logistics handling equipment, forklifts rely on their mast system, a core component for cargo handling, stacking, and loading / unloading. The mast typically comprises an outer mast, a middle mast, and an inner mast, and uses a hydraulic system to drive lifting cylinders and a chain mechanism to achieve vertical lifting of the forks. Currently, the fully free mast structure is widely used in forklift design. It employs a two-stage lifting method—front and rear lifting cylinders—in conjunction with a chain drive mechanism to achieve progressive lifting of the mast. Specifically, during cargo lifting, the front lifting cylinder actuates first, raising the fork carriage and forks; after the front lifting cylinder completes its stroke, the rear lifting cylinder continues, raising the inner mast, thus achieving the maximum lifting height.

[0003] However, in certain specific working conditions, such as when forklifts are used for high-level unloading and stacking bagged materials, operators often use a method where the forks slide out along the top of the goods to retract them, in order to avoid the forks scraping against the goods and causing a tipping. During this operation, the forks and fork carriage are always vertically supported by the goods, causing the mast chain to be in a slack state. When the forks are completely separated from the goods, the fork carriage and chain undergo free fall under the action of gravity until the chain is re-tensioned. This process can easily cause violent vibrations in the chain. During the vibration, the chain plates may hit the piston rod of the front lifting cylinder, causing damage to the piston rod surface. With the increase in the frequency of forklift operation, the damaged piston rod will further damage the cylinder sealing system, eventually leading to cylinder oil leakage, affecting the normal operation and service life of the forklift. To address this, a tensioning device for the forklift mast and its forklift mast are proposed. Utility Model Content

[0004] The purpose of this utility model is to provide a tensioning device for a forklift mast and the forklift mast thereof, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a tensioning device for a forklift mast, used to tension the front cylinder chain of the forklift mast, comprising:

[0006] A front cylinder chain plate is mounted on the forklift mast. The front cylinder chain plate has holes that pass through the upper and lower end faces. A sleeve assembly is provided on the end face of the front cylinder chain plate away from the front cylinder chain.

[0007] A connector, one end of which is connected to the front cylinder chain, and the other end of which passes through a hole into the interior of the sleeve assembly and connects to the tie rod assembly; and

[0008] A first fastener on the tie rod assembly keeps the pressure plate assembly in contact with the sleeve assembly. A limiting block that is slidably connected to the tie rod assembly is provided inside the sleeve assembly. A second fastener is provided on the joint between the front cylinder chain plate and the limiting block. The outer circumferential surface of the tie rod assembly is provided with elastic elements at both ends that are in contact with the limiting block and the inner wall of the pressure plate assembly, respectively. When the front cylinder chain is in an abnormal working state, the elastic elements release the stored pressure and push the pressure plate assembly to move away from the sleeve assembly. The movement of the pressure plate assembly transmits the force through the tie rod assembly and the joint, thereby tightening the front cylinder chain and keeping it in a taut state.

[0009] As a further embodiment of this invention: the end of the connector is inserted into the interior of the pull rod assembly and threadedly connected thereto.

[0010] As a further embodiment of this utility model: the outer peripheral surface of the pull rod assembly is provided with a cotter pin that is inserted into the end connector.

[0011] A forklift mast includes the aforementioned tensioning device, and further includes an outer mast connected to the vehicle body, a middle mast disposed on the outer mast, and an inner mast disposed on the middle mast, wherein a fork carriage is disposed on the inner mast, and forks are mounted on the fork carriage.

[0012] As a further embodiment of this utility model: roller sets are respectively provided on the outer mast, middle mast and inner mast, and the roller sets include main rollers and side rollers. Main rollers and side rollers are arranged between the outer mast and the middle mast, between the middle mast and the inner mast, and between the inner mast and the fork carriage.

[0013] As a further embodiment of this utility model: a front lifting cylinder is installed on the lower crossbeam of the inner mast, the front lifting cylinder is connected to the front cylinder chain plate, and the front cylinder chain plate is connected to the middle crossbeam of the inner mast by a third fastener.

[0014] As a further embodiment of this utility model: a front sprocket is installed at the cylinder head end of the front lifting cylinder, and a front cylinder chain is provided on the outer circumferential surface of the front sprocket. One end of the front cylinder chain is connected to the connector, and the other end passes around the front sprocket and is connected to the chain seat of the fork carriage.

[0015] As a further embodiment of this invention: a limiting plate is installed on the front sprocket to prevent the front cylinder chain from detaching from the front sprocket.

[0016] As a further embodiment of this utility model: two rear lifting cylinders are provided on the outer gantry, and the telescopic ends of the rear lifting cylinders are connected to the middle gantry. A rear sprocket is installed on the upper crossbeam of the middle gantry, and a rear cylinder chain is provided on the outer circumference of the rear sprocket. One end of the rear cylinder chain is connected to the inner gantry, and the other end passes around the rear sprocket and is connected to the outer gantry.

[0017] Compared with the prior art, the beneficial effects of this utility model are:

[0018] This application achieves effective tension control of the front cylinder chain by adding a tensioning device without altering the original mast structure. It is suitable for both retrofitting existing equipment and developing new products, significantly reducing retrofitting costs and assembly complexity. Furthermore, the tensioning device provides continuous constraint on the front cylinder chain, effectively suppressing lateral swaying under abnormal operating conditions and keeping the amplitude within safe limits. This completely prevents abnormal contact between the chain and components such as the mast body and cylinder piston rod, preventing chain wear and breakage and piston rod surface damage caused by mechanical interference. In addition, the tensioning device enables the forklift mast to withstand harsh operating conditions such as high-frequency vibration and heavy-load impact, improving product reliability and broadening its applications, resulting in significant economic benefits and a competitive market advantage. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of an existing forklift mast for this utility model;

[0020] Figure 2 This is a side view of an existing forklift mast according to the present invention;

[0021] Figure 3 This is a schematic diagram of the existing forklift mast tensioning device according to the present invention;

[0022] Figure 4 For the present utility model Figure 3 A magnified view of a portion of the image;

[0023] Figure 5 This is a first schematic diagram of the tensioning device of this utility model under normal and abnormal conditions;

[0024] Figure 6 This is a second schematic diagram of the tensioning device of this utility model under normal and abnormal conditions;

[0025] Figure 7 This is a schematic diagram of the sleeve assembly of this utility model;

[0026] Figure 8 This is a schematic diagram of the connector of this utility model;

[0027] Figure 9 This is a schematic diagram of the tie rod assembly of this utility model;

[0028] In the diagram: 1. Outer mast; 2. Middle mast; 3. Inner mast; 4. Fork carriage; 5. Forks; 6. Roller assembly; 61. Main roller; 62. Side roller; 7. Front lifting cylinder; 8. Front cylinder chain plate; 9. Third fastener; 10. Front sprocket; 11. Front cylinder chain; 12. Limiting plate; 13. Rear sprocket; 14. Rear cylinder chain; 15. Sleeve assembly; 151. First hollow tube; 152. Second hollow tube; 16. Connector; 161. Connecting seat; 162. Connecting rod; 17. Tie rod assembly; 171. Threaded sleeve; 172. Threaded rod; 18. First fastener; 19. Pressure plate assembly; 20. Limiting block; 21. Second fastener; 22. Elastic element; 23. Cotter pin; 24. Rear lifting cylinder. Detailed Implementation

[0029] 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.

[0030] Please see Figure 1-9 In this embodiment of the present invention, a tensioning device for a forklift mast is provided for tensioning the front cylinder chain 11 of the forklift mast, comprising:

[0031] The front cylinder chain plate 8 is mounted on the forklift mast. The front cylinder chain plate 8 has holes that pass through the upper and lower end faces. The end face of the front cylinder chain plate 8 away from the front cylinder chain 11 is provided with a sleeve assembly 15.

[0032] One end of a connector 16 is connected to the front cylinder chain 11, and the other end of the connector 16 passes through a hole into the interior of the sleeve assembly 15 and is connected to the tie rod assembly 17; and

[0033] The first fastener 18 on the pull rod assembly 17 keeps the sleeve assembly 15 in contact with the pressure plate assembly 19. A limiting block 20 is provided inside the sleeve assembly 15 and is slidably connected to the pull rod assembly 17. A second fastener 21 is provided on the joint 16 between the front cylinder chain plate 8 and the limiting block 20. The outer circumferential surface of the pull rod assembly 17 is provided with elastic elements 22 at both ends that are in contact with the limiting block 20 and the inner wall of the pressure plate assembly 19, respectively. When the front cylinder chain 11 is in an abnormal working state, the elastic element 22 releases the stored pressure and pushes the pressure plate assembly 19 to move away from the sleeve assembly 15. The movement of the pressure plate assembly 19 transmits the force through the pull rod assembly 17 and the joint 16, thereby tightening the front cylinder chain 11 and keeping it in a taut state.

[0034] Specifically, the connector 16 includes a connecting seat 161 connected to the front cylinder chain 11 and a connecting rod 162 passing through a hole. The connecting seat 161 is connected to the connecting rod 162. The end face of the connecting rod 162 away from the connecting seat 161 has an external thread. The outer diameter of the connecting rod 162 is adapted to the inner diameter of the hole, which facilitates the lifting and lowering of the connecting rod 162 along the length of the hole. The outer diameter of the connecting seat 161 is larger than the inner diameter of the hole, which can prevent one end of the connecting rod 162 from detaching from the hole. A sleeve assembly 15 is installed on the end face of the front cylinder chain plate 8 away from the connecting seat 161. The sleeve assembly 15 includes a first hollow tube 151 and a second hollow tube 152 connected to each other. The end of the first hollow tube 151 is fixedly connected to the front cylinder chain plate 8, and its interior is connected to the hole. The connection allows the end of the connecting rod 162 to pass through the hole and enter the interior of the first hollow tube 151. A limiting block 20 is installed inside the second hollow tube 152. The threaded end of the connecting rod 162 is inserted into the interior of the pull rod assembly 17 and threadedly connected thereto. The pull rod assembly 17 includes a threaded sleeve 171 and a threaded rod 172 connected to the connecting rod 162. The end of the threaded sleeve 171 passes through the limiting block 20, and the two are movably connected. A second fastener 21, which is a double nut, is threaded onto the connecting rod 162. By rotating the position of the double nut on the connecting rod 162, the length of the connecting rod 162 extending out of the front cylinder chain plate 8 in the normal state of the front cylinder chain 11 can be adjusted. The range of motion of the double nut is between the limiting block 20 and the... The area between the front cylinder chain plates 8 is the tensioning area of ​​the front cylinder chain 11. Under normal conditions, the double nuts are in contact with the front cylinder chain plates 8. The longer the length of the front cylinder chain 11, the shorter the extension distance of the connecting rod 162; conversely, the shorter the length of the front cylinder chain 11, the longer the extension distance of the connecting rod 162. This ensures that the connecting seat 161 is connected to the end of the front cylinder chain 11. The end of the threaded rod 172 away from the threaded sleeve 171 passes through the second hollow tube 152 and the pressure plate assembly 19 in sequence and is threaded with the first fastener 18, which is a nut. By rotating the nut on the threaded rod 172, the end of the pressure plate assembly 19 is kept in contact with the second hollow tube 152. The outer circumferential surface of the pull rod assembly 17 is provided with The elastic element 22, which is a spring, is in contact with the inner wall of the limiting block 20 and the pressure plate assembly 19 at both ends. When the front cylinder chain 11 is in a normal state, the spring is in a compressed state, the double nuts are in contact with the front cylinder chain plate 8, and the pressure plate assembly 19 is in contact with the second hollow tube 152. When the front cylinder chain 11 malfunctions and becomes momentarily slack, the spring begins to reset due to the release of its compressive potential energy and applies a certain thrust to the pressure plate assembly 19. This thrust pushes the pressure plate assembly 19 to move in a set direction, and in turn drives the pull rod assembly 17, the connector 16, and one end of the front cylinder chain 11 to move in the direction of spring reset. The spring stores elastic potential energy in the compressed state, and when the front cylinder chain 11 slacks, it releases this energy and converts it into mechanical thrust.This mechanism actively compensates for length changes in the front cylinder chain 11 caused by abnormal conditions. Through this mechanism, the front cylinder chain 11 can quickly recover and maintain a taut state, preventing vibration and swaying caused by slackness. This, in turn, avoids the front cylinder chain 11 colliding with the cylinder piston rod and other components, preventing damage to the front cylinder chain 11 and related parts.

[0035] Please see Figure 5-6 In one embodiment, preferably, the outer peripheral surface of the pull rod assembly 17 is provided with a cotter pin 23 that is inserted into the connector 16. By inserting the end of the cotter pin 23 into the connector 16 and the pull rod assembly 17, the rotation of the pull rod assembly 17 relative to the connector 16 can be restricted, and further prevent the pull rod assembly 17 from disengaging from the connector 16.

[0036] Under normal conditions, the distance between the connecting seat 161 and the front cylinder chain plate 8 is set to H2. The size of H2 is related to the state of the front cylinder chain 11 assembled in the forklift mast. The shorter the length of the front cylinder chain 11, the larger the distance H2 (e.g., ...). Figure 5 As shown), conversely, the longer the current cylinder chain 11 is, the smaller the distance of H2 (as shown). Figure 6 As shown, the size of H2 is adjusted by rotating the second fastener 21 on the connecting rod 162. The closer the second fastener 21 is to the tie rod assembly 17, the larger H2 is; the closer the second fastener 21 is to the front cylinder chain plate 8, the smaller H2 is.

[0037] Please see Figure 5-6 Under normal operating conditions, the double nuts tightly adhere to the surface of the front cylinder chain plate 8, restricting the joint 16 from moving toward the front cylinder chain 11 to ensure chain tension. Specifically, one end of the pull rod assembly 17 is connected to the threaded joint 16, and the other end passes through the spring, pressure plate assembly 19, and the first fastener 18.

[0038] In abnormal operating conditions, the unstable operation of the forklift causes the front cylinder chain 11 to oscillate, resulting in a momentary slack in the front cylinder chain 11. At this time, the spring compression force is released instantly, causing the spring to return to its original position and simultaneously tightening the connector 16 to ensure that the front cylinder chain 11 is in a taut state, preventing it from swinging laterally and impacting surrounding objects or the cylinder piston rod, thus preventing damage to the components.

[0039] When transitioning from normal to abnormal operation, the double nuts disengage from the surface of the front cylinder chain plate 8, causing the connector 16 to move. At this time, the spring extends but remains compressed, ensuring that the front cylinder chain 11 can quickly return to tension. Once the abnormal operation returns to normal, the front cylinder chain 11 will reset to its normal position under the weight of the fork carriage 4 and its load. Figure 6 or Figure 7 The state.

[0040] Furthermore, once the unstable state under abnormal operating conditions disappears, the spring no longer extends, meaning that the adjacent end faces of the pressure plate assembly 19 and the sleeve assembly 15 close again, indicating that the system has returned to a stable operating state.

[0041] Please see Figure 1-3 A forklift mast includes a tensioning device and further includes an outer mast 1 connected to the vehicle body, a middle mast 2 disposed on the outer mast 1, and an inner mast 3 disposed on the middle mast 2. A fork carriage 4 is disposed on the inner mast 3, and forks 5 are mounted on the fork carriage 4. The inner mast 3 is symmetrically nested inside the middle mast 2, the middle mast 2 is symmetrically nested inside the outer mast 1, and the fork carriage 4 is symmetrically nested inside the inner mast 3. All structures are symmetrically arranged with the center line as the reference. The middle mast 2 is placed between the outer mast 1 and the inner mast 3, and the inner mast 3, the middle mast 2, and the outer mast 1 are staggered by 10mm or flush.

[0042] Please see Figure 1 In one embodiment, preferably, roller sets 6 are respectively provided on the outer mast 1, the middle mast 2 and the inner mast 3. The roller sets 6 include main rollers 61 and side rollers 62. Main rollers 61 and side rollers 62 are arranged between the outer mast 1 and the middle mast 2, between the middle mast 2 and the inner mast 3, and between the inner mast 3 and the fork carriage 4. The main rollers 61 are installed in the channel steel structure of the outer mast 1, the middle mast 2 and the inner mast 3.

[0043] Please see Figure 3 In one embodiment, preferably, a front lifting cylinder 7 is installed on the lower crossbeam of the inner mast 3. The front lifting cylinder 7 is connected to the front cylinder chain plate 8, and the front cylinder chain plate 8 is connected to the middle crossbeam of the inner mast 3 by a third fastener 9.

[0044] Please see Figure 3 In one embodiment, preferably, a front sprocket 10 is installed at the cylinder head end of the front lifting cylinder 7. A front cylinder chain 11 is provided on the outer circumferential surface of the front sprocket 10. One end of the front cylinder chain 11 is connected to the connector 16, and the other end passes around the front sprocket 10 and is connected to the chain seat of the fork carriage 4. A limit plate 12 is installed on the front sprocket 10 to prevent the front cylinder chain 11 from detaching from the front sprocket 10.

[0045] Please see Figure 2 In one embodiment, preferably, the outer gantry 1 is provided with two rear lifting cylinders 24, the telescopic ends of which are connected to the middle gantry 2. The upper crossbeam of the middle gantry 2 is equipped with a rear sprocket 13, and the outer circumferential surface of the rear sprocket 13 is provided with a rear cylinder chain 14. One end of the rear cylinder chain 14 is connected to the inner gantry 3, and the other end passes around the rear sprocket 13 and is connected to the outer gantry 1. The rear sprocket 13 can rotate clockwise or counterclockwise.

[0046] The lifting and lowering working principle of the forklift mast is based on existing technology and has not been modified. It is knowledge that is well known to those skilled in the art, and will not be elaborated on here. For specific structure and principle, please refer to (CN104129738B).

[0047] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0048] Therefore, the above description is only a preferred embodiment of this application and is not intended to limit the scope of this application; that is, all equivalent modifications made in accordance with the scope of the claims of this application shall be within the protection scope of the claims of this application.

Claims

1. A tensioning device for a forklift mast, used to tension the front cylinder chain of the forklift mast, characterized in that, include: A front cylinder chain plate is mounted on the forklift mast. The front cylinder chain plate has holes that pass through the upper and lower end faces. A sleeve assembly is provided on the end face of the front cylinder chain plate away from the front cylinder chain. A connector, one end of which is connected to the front cylinder chain, and the other end of which passes through a hole into the interior of the sleeve assembly and connects to the tie rod assembly; and A first fastener on the tie rod assembly keeps the pressure plate assembly in contact with the sleeve assembly. A limiting block that is slidably connected to the tie rod assembly is provided inside the sleeve assembly. A second fastener is provided on the joint between the front cylinder chain plate and the limiting block. The outer circumferential surface of the tie rod assembly is provided with elastic elements at both ends that are in contact with the limiting block and the inner wall of the pressure plate assembly, respectively. When the front cylinder chain is in an abnormal working state, the elastic elements release the stored pressure and push the pressure plate assembly to move away from the sleeve assembly. The movement of the pressure plate assembly transmits the force through the tie rod assembly and the joint, thereby tightening the front cylinder chain and keeping it in a taut state.

2. The tensioning device for a forklift mast according to claim 1, characterized in that, The end of the connector is inserted into the interior of the tie rod assembly and threaded thereon.

3. The tensioning device for a forklift mast according to claim 2, characterized in that, The outer circumferential surface of the tie rod assembly is provided with a cotter pin that is inserted into the end connector.

4. A forklift mast, comprising the tensioning device as described in claim 1, characterized in that, It further includes an outer mast connected to the vehicle body, a middle mast disposed on the outer mast, and an inner mast disposed on the middle mast, wherein a fork carriage is disposed on the inner mast and forks are mounted on the fork carriage.

5. The forklift mast according to claim 4, characterized in that, Roller assemblies are respectively provided on the outer mast, middle mast and inner mast. The roller assemblies include main rollers and side rollers. Main rollers and side rollers are arranged between the outer mast and middle mast, between the middle mast and inner mast, and between the inner mast and fork carriage.

6. The forklift mast according to claim 4, characterized in that, A front lifting cylinder is installed on the lower crossbeam of the inner mast. The front lifting cylinder is connected to the front cylinder chain plate, and the front cylinder chain plate is connected to the middle crossbeam of the inner mast by a third fastener.

7. The forklift mast according to claim 6, characterized in that, The front lifting cylinder is equipped with a front sprocket at the cylinder head end. The outer circumference of the front sprocket is provided with a front cylinder chain. One end of the front cylinder chain is connected to the connector, and the other end passes around the front sprocket and is connected to the chain seat of the fork carriage.

8. The forklift mast according to claim 7, characterized in that, A limit plate is installed on the front sprocket to prevent the front cylinder chain from detaching from the front sprocket.

9. The forklift mast according to claim 4, characterized in that, The outer gantry is equipped with two rear lifting cylinders. The telescopic ends of the rear lifting cylinders are connected to the middle gantry. A rear sprocket is installed on the upper crossbeam of the middle gantry. A rear cylinder chain is provided on the outer circumference of the rear sprocket. One end of the rear cylinder chain is connected to the inner gantry, and the other end passes around the rear sprocket and is connected to the outer gantry.

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