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 the transformation cost and the assembly complexity are remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of forklift masts, in particular to a tensioning device for a forklift mast and the forklift mast. Background Art

[0002] As an important part of logistics handling equipment, the gantry system in the working device of a forklift is the core component for realizing the functions of cargo handling, stacking, and loading and unloading. The gantry usually includes an outer gantry, a middle gantry, and an inner gantry, and drives the lifting cylinder and chain mechanism through a hydraulic system to realize the vertical lifting movement of the fork. At present, the full-free gantry structure is widely used in forklift design. It realizes the step-by-step lifting of the gantry through a two-stage lifting method of the front lifting cylinder and the rear lifting cylinder in conjunction with the chain transmission mechanism. Specifically, during the cargo lifting process, the front lifting cylinder is actuated first, driving the fork frame and the fork to rise; after the stroke of the front lifting cylinder is completed, the rear lifting cylinder continues to act, driving the inner gantry to rise, thereby achieving the maximum lifting height.

[0003] However, under certain specific working conditions, such as when a forklift is used to unload goods at high positions and stack bagged materials, the operator often uses the fork to slide out along the top of the goods to retract the fork to avoid the fork scratching the goods and causing overturning. During this operation, the fork and the fork frame are always supported vertically by the goods, causing the mast chain to be in a slack state. When the fork is completely separated from the goods, the fork frame and the chain produce a free fall motion under the action of gravity until the chain is re-tightened. This process can easily cause violent oscillations of the chain. During the oscillation, the chain plate may hit the piston rod of the front lifting cylinder, causing damage to the piston rod surface. As the frequency of forklift operations increases, the damaged piston rod will further damage the cylinder sealing system, eventually causing the cylinder to leak oil, affecting the normal operation and service life of the forklift. For this reason, a tensioning device for a forklift mast and a forklift mast are proposed. Summary of the Invention

[0004] The object of the present invention is to provide a tensioning device for a forklift mast and the forklift mast, so as to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned object, the present invention provides the following technical solution: a tensioning device for a forklift mast, used for tensioning a front cylinder chain of the forklift mast, comprising:

[0006] A front cylinder chain plate is provided on the forklift mast, the front cylinder chain plate having holes extending through the upper and lower end surfaces, and a sleeve assembly is provided on the end surface of the front cylinder chain plate away from the front cylinder chain;

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

[0008] The pressure plate assembly is kept in contact with the sleeve assembly by a first fastener arranged on the pull rod assembly, a limit block slidingly connected to the pull rod assembly is provided in the sleeve assembly, and a second fastener located between the front cylinder chain plate and the limit block is provided on the joint. The outer peripheral surface of the pull rod assembly is provided with an elastic member whose two ends respectively keep in contact with the limit block and the inner wall of the pressure plate assembly. When the front cylinder chain is in an abnormal working state, the elastic member releases the stored pressure and pushes the pressure plate assembly to move away from the sleeve assembly. The movement of the pressure plate assembly transmits the force through the pull rod assembly and the joint, thereby tightening the front cylinder chain to keep it in a taut state.

[0009] As a further solution of the present invention, the end of the joint is inserted into the interior of the pull rod assembly and is threadedly connected thereto.

[0010] As a further solution of the present invention: the outer peripheral surface of the pull rod assembly is provided with a cotter pin whose end is inserted into the joint.

[0011] A forklift mast comprises the tensioning device described above, and further comprises an outer mast connected to the vehicle body, a middle mast arranged on the outer mast, and an inner mast arranged on the middle mast, wherein the inner mast is provided with a fork frame, and the fork frame is mounted with a fork.

[0012] As a further solution of the present invention: roller groups are respectively provided on the outer mast, middle mast and inner mast, and the roller groups include main rollers and side rollers. Main rollers and side rollers are configured between the outer mast and the middle mast, between the middle mast and the inner mast, and between the inner mast and the fork frame.

[0013] As a further solution of the present invention: 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 through a third fastener.

[0014] As a further solution of the present invention: 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 peripheral surface of the front sprocket. One end of the front cylinder chain is connected to the joint, and the other end passes around the front sprocket and is connected to the chain seat of the fork frame.

[0015] As a further solution of the present invention: a limit plate is installed on the front sprocket to prevent the front cylinder chain from detaching from the front sprocket.

[0016] As a further solution of the present invention: two rear lifting cylinders are provided on the outer mast, the telescopic ends of the rear lifting cylinders are connected to the middle mast, a rear sprocket is installed on the upper crossbeam of the middle mast, a rear cylinder chain is provided on the outer peripheral surface of the rear sprocket, one end of the rear cylinder chain is connected to the inner mast, and the other end passes around the rear sprocket and is connected to the outer mast.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] This application achieves effective tensioning control of the front cylinder chain by adding a tensioning device without changing the original mast structure. It is suitable for the transformation of existing equipment and compatible with new product development, which significantly reduces the transformation cost and assembly complexity. The tensioning device can form a continuous restraining force on the front cylinder chain, effectively suppressing the lateral swing of the chain under abnormal working conditions, controlling the swing amplitude within a safe value, and completely avoiding abnormal contact between the chain and the mast body, cylinder piston rod and other components, preventing chain wear and breakage and piston rod surface damage due to mechanical interference. In addition, the tensioning device enables the forklift mast to have the ability to cope with harsh working conditions such as high-frequency vibration and heavy-load impact, so that the reliability of the product is improved and its application is wider, with significant economic benefits and market competitive advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of a conventional forklift mast of the present invention;

[0020] Figure 2 It is a side view schematic diagram of a conventional forklift mast of the present invention;

[0021] Figure 3 This is a schematic diagram of a tensioning device for assembling a conventional forklift mast of the present invention;

[0022] Figure 4 For the present invention Figure 3 A partial enlarged schematic diagram;

[0023] Figure 5 This is a first schematic diagram of the tensioning device of the present invention in a normal state and an abnormal state;

[0024] Figure 6 A second schematic diagram of the tensioning device of the present invention in a normal state and an abnormal state;

[0025] Figure 7 is a schematic diagram of the sleeve assembly of the present invention;

[0026] Figure 8 Schematic diagram of the joint of the present invention;

[0027] Figure 9 Schematic diagram of the tie rod assembly of the present invention;

[0028] In the figure: 1. outer mast; 2. middle mast; 3. inner mast; 4. fork frame; 5. fork; 6. roller assembly; 61. main roller; 62. side roller; 7. front lifting cylinder; 8. front cylinder hanging chain plate; 9. third fastener; 10. front sprocket; 11. front cylinder chain; 12. limit plate; 13. rear sprocket; 14. rear cylinder chain; 15. sleeve assembly; 151. first hollow tube; 152. second hollow tube; 16. joint; 161. connecting seat; 162. connecting rod; 17. pull rod assembly; 171. threaded sleeve; 172. threaded rod; 18. first fastener; 19. pressure plate assembly; 20. limit block; 21. second fastener; 22. elastic member; 23. cotter pin; 24. rear lifting cylinder. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] See also Figure 1-9 In an embodiment of the present invention, a tensioning device for a forklift mast is used to tension a front cylinder chain 11 of the forklift mast, comprising:

[0031] The front cylinder chain plate 8 is provided on the forklift mast. The front cylinder chain plate 8 has holes penetrating the upper and lower end surfaces. The end surface of the front cylinder chain plate 8 away from the front cylinder chain 11 is provided with a sleeve assembly 15;

[0032] A connector 16 connected to the front cylinder chain 11 at one end, with the other end of the connector 16 passing through a hole into the interior of the sleeve assembly 15 and connected to the pull rod assembly 17; and

[0033] The sleeve assembly 15 is kept in contact with the pressure plate assembly 19 by a first fastener 18 arranged on the pull rod assembly 17. A limit block 20 slidingly connected to the pull rod assembly 17 is provided in the sleeve assembly 15. A second fastener 21 is provided on the joint 16 and located between the front cylinder chain plate 8 and the limit block 20. The outer peripheral surface of the pull rod assembly 17 is provided with an elastic member 22 whose two ends respectively keep in contact with the limit block 20 and the inner wall of the pressure plate assembly 19. When the front cylinder chain 11 is in an abnormal working state, the elastic member 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 to keep it in a taut state.

[0034] Specifically, the joint 16 includes a connecting seat 161 connected to the front cylinder chain 11 and a connecting rod 162 passing through the hole. The connecting seat 161 is connected to the connecting rod 162, and 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 movement of the connecting rod 162 along the length direction of the hole, and the outer diameter of the connecting seat 161 is larger than the inner diameter of the hole, which can limit one end of the connecting rod 162 from being separated 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 aligned with the hole. The connection is convenient for the end of the connecting rod 162 to penetrate the hole into the interior of the first hollow tube 151, and a limit block 20 is installed inside the second hollow tube 152. The end of the connecting rod 162 with an external thread 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 limit block 20, and the two are movably connected. A second fastener 21 is threadedly sleeved on the connecting rod 162. The second fastener 21 is a double nut. 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 when the front cylinder chain 11 is in the normal state can be adjusted. The movable range of the double nut is the limit 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 nut maintains contact with the front cylinder chain plate 8. When the length of the front cylinder chain 11 is longer, the distance the connecting rod 162 extends is shorter. Conversely, when the length of the front cylinder chain 11 is shorter, the distance the connecting rod 162 extends is longer. This ensures that the connecting seat 161 is connected to the end of the front cylinder chain 11, and 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 turn and is threadedly sleeved with a first fastener 18. The first fastener 18 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 peripheral surface of the pull rod assembly 17 is provided with The elastic member 22 at both ends keeps in contact with the limit block 20 and the inner wall of the pressure plate assembly 19 respectively. The elastic member 22 is a spring. When the front cylinder chain 11 is in a normal state, the spring remains in a compressed state, the double nut contacts the front cylinder chain plate 8, and the pressure plate assembly 19 contacts the second hollow tube 152. When the front cylinder chain 11 becomes abnormal and relaxes instantly, the spring begins to reset due to the release of compression potential energy and exerts a certain thrust on the pressure plate assembly 19. The thrust pushes the pressure plate assembly 19 to move in the set direction, and in turn drives the pull rod assembly 17, the joint 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 a compressed state, and converts the energy into mechanical thrust by releasing it when the front cylinder chain 11 is relaxed.This actively compensates for the length change of the front cylinder chain 11 caused by abnormal conditions. Through this mechanism, the front cylinder chain 11 can quickly recover and always remain taut, preventing vibration and swing caused by relaxation of the front cylinder chain 11. This prevents the front cylinder chain 11 from hitting other components such as the cylinder piston rod, preventing damage to the front cylinder chain 11 and related components.

[0035] See also Figure 5-6 In one embodiment, in this embodiment, preferably, the outer peripheral surface of the tie rod assembly 17 is provided with a cotter pin 23 whose end is inserted into the joint 16. By inserting the end of the cotter pin 23 into the joint 16 and the tie rod assembly 17, the tie rod assembly 17 can be restricted from rotating relative to the joint 16, further preventing the tie rod assembly 17 from being separated from the joint 16.

[0036] In normal state, 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), on the contrary, the longer the length of the current cylinder chain 11 is, the smaller the distance H2 is (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 pull rod assembly 17, the larger H2 is, and the closer the second fastener 21 is to the front cylinder chain plate 8, the smaller H2 is.

[0037] See also Figure 5-6 Under normal working conditions, the double nuts are tightly attached to the surface of the front cylinder chain plate 8 to limit the movement of the joint 16 toward the front cylinder chain 11 to ensure the chain tension. Specifically, one end of the pull rod assembly 17 is connected to the joint 16 through a thread, and the other end passes through the spring, the pressure plate assembly 19 and the first fastener 18.

[0038] Under abnormal working conditions, the unstable operation of the forklift causes the front cylinder chain 11 to vibrate, causing the front cylinder chain 11 to relax instantly. At this time, the spring compression force is released instantly, prompting the spring to return to its position and simultaneously tightening the joint 16 to ensure that the front cylinder chain 11 is in a tensioned state, preventing its lateral swing from impacting surrounding objects or the cylinder piston rod, thereby preventing component damage.

[0039] When the normal working state is changed to the abnormal working state, the double nut is separated from the surface of the front cylinder chain plate 8, so that the joint 16 moves. At this time, the spring is extended but still remains in a compressed state, ensuring that the front cylinder chain 11 can quickly restore the tension state. Once the abnormal working condition returns to normal, the front cylinder chain 11 will return to the original state under the action of the gravity of the fork frame 4 and its load. Figure 6 or Figure 7 status.

[0040] In addition, when the unstable state under the abnormal working condition disappears, the spring no longer extends, that is, the end surfaces adjacent to the pressure plate assembly 19 and the sleeve assembly 15 are closed again, which indicates that the system has returned to a stable working state.

[0041] See also Figure 1-3 A forklift mast, including a tensioning device, further includes an outer mast 1 connected to the vehicle body, a middle mast 2 arranged on the outer mast 1 and an inner mast 3 arranged on the middle mast 2, the inner mast 3 is provided with a fork frame 4, and the fork frame 4 is installed with a fork 5, 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 frame 4 is symmetrically nested inside the inner mast 3, and each structure is 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 10 mm or flush in sequence.

[0042] See also Figure 1 In one embodiment, in this embodiment, preferably, roller groups 6 are respectively provided on the outer mast 1, the middle mast 2 and the inner mast 3, and the roller groups 6 include main rollers 61 and side rollers 62. Main rollers 61 and side rollers 62 are provided 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 frame 4, wherein the main rollers 61 are installed in the channel steel structures of the outer mast 1, the middle mast 2 and the inner mast 3.

[0043] See also Figure 3 In one embodiment, in this 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 through a third fastener 9.

[0044] See also Figure 3 In one embodiment, in this embodiment, preferably, a front sprocket 10 is installed at the cylinder head end of the front lifting cylinder 7, and a front cylinder chain 11 is provided on the outer peripheral surface of the front sprocket 10. One end of the front cylinder chain 11 is connected to the joint 16, and the other end is connected to the chain seat of the fork frame 4 after passing around the front sprocket 10. 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] See also Figure 2 In one embodiment, in this embodiment, preferably, two rear lifting cylinders 24 are provided on the outer mast 1, and the telescopic ends of the rear lifting cylinders 24 are connected to the middle mast 2, and a rear sprocket 13 is installed on the upper crossbeam of the middle mast 2. The outer peripheral 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 mast 3, and the other end bypasses the rear sprocket 13 and is connected to the outer mast 1, wherein the rear sprocket 13 can rotate clockwise or counterclockwise.

[0046] The lifting and lowering working principles of the forklift mast are all existing technologies and have not been changed. They are knowledge well known to those skilled in the art and will not be described in detail here. For the specific structure and principles, please refer to (CN104129738B).

[0047] Although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0048] Therefore, the above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application; that is, all equivalent modifications made according to the scope of the claims of the present application are within the scope of protection of the claims of the present application.

Claims

1. A tensioning device for a forklift mast, used for tensioning the front cylinder chain of the forklift mast, characterized in that: include: A front cylinder chain plate is provided on the forklift mast, the front cylinder chain plate having holes extending through the upper and lower end surfaces, and a sleeve assembly is provided on the end surface of the front cylinder chain plate away from the front cylinder chain; A connector having one end connected to the front cylinder chain, the other end of which is passed through a hole into the interior of the sleeve assembly and connected to the pull rod assembly; and The pressure plate assembly is kept in contact with the sleeve assembly by a first fastener arranged on the pull rod assembly, a limit block slidingly connected to the pull rod assembly is provided in the sleeve assembly, and a second fastener located between the front cylinder chain plate and the limit block is provided on the joint. The outer peripheral surface of the pull rod assembly is provided with an elastic member whose two ends respectively keep in contact with the limit block and the inner wall of the pressure plate assembly. When the front cylinder chain is in an abnormal working state, the elastic member releases the stored pressure and pushes the pressure plate assembly to move away from the sleeve assembly. The movement of the pressure plate assembly transmits the force through the pull rod assembly and the joint, thereby tightening the front cylinder chain to keep it in a taut state.

2. The tensioning device for a forklift mast according to claim 1, characterized in that: The end of the joint is inserted into the interior of the pull rod assembly and threadedly connected therewith.

3. The tensioning device for a forklift mast according to claim 2, characterized in that: The outer peripheral surface of the pull rod assembly is provided with a cotter pin whose end is inserted into the joint.

4. A forklift mast, comprising the tensioning device according to claim 1, characterized in that: It further includes an outer mast connected to the vehicle body, a middle mast arranged on the outer mast, and an inner mast arranged on the middle mast. The inner mast is provided with a fork frame, and the fork frame is installed with a fork.

5. The forklift mast according to claim 4, characterized in that: The outer mast, middle mast and inner mast are respectively provided with roller groups, and the roller groups include main rollers and side rollers. Main rollers and side rollers are configured between the outer mast and middle mast, between the middle mast and inner mast, and between the inner mast and the fork frame.

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

7. The forklift mast according to claim 6, characterized in that: 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 peripheral surface of the front sprocket. One end of the front cylinder chain is connected to the joint, and the other end is connected to the chain seat of the fork frame after passing around the front sprocket.

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: Two rear lifting cylinders are provided on the outer mast, and the telescopic ends of the rear lifting cylinders are connected to the middle mast. A rear sprocket is installed on the upper crossbeam of the middle mast, and a rear cylinder chain is provided on the outer peripheral surface of the rear sprocket. One end of the rear cylinder chain is connected to the inner mast, and the other end passes around the rear sprocket and is connected to the outer mast.

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