Freely-lifting three-stage portal frame for forklift

Abstract

The invention discloses a three-stage portal frame for a free lifting forklift. The three-stage portal frame comprises an outer portal frame body, a middle portal frame body, an inner portal frame body and a fork tool. The outer door frame is installed on a frame of the forklift, the middle door frame is assembled in the outer door frame, the inner door frame is assembled in the middle door frame, and the fork tool is assembled in the inner door frame; the three-stage portal frame further comprises a portal frame lifting assembly and a free lifting assembly. The portal frame lifting assembly comprises a portal frame lifting oil cylinder, a portal frame chain wheel and a portal frame lifting chain, the portal frame chain wheel is installed at the top position of the middle portal frame, one end of the portal frame lifting chain is fixedly installed on the upper portion of the outer portal frame, the portal frame lifting chain winds around the portal frame chain wheel, and then the other end of the portal frame lifting chain is fixed to the inner portal frame; free lifting mechanisms are installed on the outer sides of the inner portal respectively, and the purpose that the portal does not act when the fork conducts lifting action is achieved. The inner portal frame has the beneficial effects that no free lifting mechanism is arranged in the inner portal frame of the technical scheme, the view field of a driver is expanded, and the operation safety is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of forklifts, and in particular to a three-stage mast for a forklift with free lifting. Background Art

[0002] The common three-stage masts of forklifts with free lifting on the current market mainly consist of an outer mast, a middle mast, an inner mast, a free-lifting mechanism, and a mast-lifting mechanism. To adapt to the use of forklifts in occasions with limited space height requirements, a free-lifting mechanism is installed in the inner mast to enable the mast not to move when the fork performs a lifting action. However, due to the existence of the free-lifting mechanism, it occupies the internal space of the inner mast, blocking the driver's vision and resulting in a poor user experience. Therefore, it is necessary to develop a three-stage mast for a forklift with free lifting. Summary of the Invention

[0003] The main technical problem to be solved by the present invention is to provide a three-stage mast for a forklift with free lifting, which solves one or more of the above-mentioned prior art problems.

[0004] To solve the above technical problem, a technical solution adopted by the present invention is: a three-stage mast for a forklift with free lifting, the innovation of which lies in: including an outer mast, a middle mast, an inner mast, a free-lifting mechanism, and a mast-lifting mechanism;

[0005] The outer mast is installed on the forklift frame, the middle mast is assembled inside the outer mast, the inner mast is assembled inside the middle mast, and the fork is assembled inside the inner mast;

[0006] The three-stage mast further includes a mast-lifting assembly, the mast-lifting assembly includes a mast sprocket and a mast-lifting chain, the mast sprocket is installed at the top position of the middle mast, one end of the mast-lifting chain is fixedly installed on the upper part of the outer mast, the mast-lifting chain bypasses the mast sprocket, and then its other end is fixed on the inner mast. The mast-lifting assembly further includes a mast-lifting oil cylinder, the bottom of the mast-lifting oil cylinder is fixed to the lower part of the outer mast, and the top of its piston rod is fixedly connected to the middle mast;

[0007] The three-stage mast further includes a free-lifting assembly, the free-lifting assembly includes a free-lifting sprocket and a free-lifting chain, the free-lifting sprocket is installed at the top of the free-lifting oil cylinder, one end of the free-lifting chain is fixed on the inner mast, the free-lifting chain bypasses the free-lifting sprocket, and then its other end is fixed on the fork. The free-lifting assembly further includes a free-lifting oil cylinder, and the bottom of the free-lifting oil cylinder is installed on the inner mast.

[0008] In some embodiments, mounting lugs are provided on the middle mast, and the mast sprocket is installed inside the mounting lugs.

[0009] In some embodiments, the triple mast further includes a mast angle adjustment assembly. The mast angle adjustment assembly includes a pitching oil cylinder. The pitching oil cylinder is hingedly installed on the forklift truck frame. The other end of the pitching oil cylinder is hingedly connected to the outer mast. The bottom of the outer mast is provided with a pin hole and a pin shaft. The outer mast is assembled on the forklift truck frame through the pin hole and the pin shaft.

[0010] In some embodiments, a first inner guide rail is provided inside the outer mast. A first roller is provided on the middle mast. The first roller can travel along the first inner guide rail. A second inner guide rail is provided inside the middle mast. A second roller is provided on the inner mast. The second roller can travel along the second inner guide rail. A third inner guide rail is provided inside the inner mast. A third roller is provided on the fork attachment. The third roller can travel along the third inner rail.

[0011] In some embodiments, the free lift oil cylinders are symmetrically installed on the outer surfaces on both sides of the inner mast, and the telescopic direction of the piston rods thereof is parallel to the longitudinal axis of the inner mast. The free lift sprockets are fixed to the tops of the free lift oil cylinders and are connected to the fork attachment through free lift chains.

[0012] In some embodiments, the cylinder barrel of the mast lift oil cylinder is fixed to the lower part of the outer mast, the top of its piston rod is connected to the upper part of the middle mast, and a tension adjustment mechanism is provided at the connection point of the mast lift chain and the upper part of the outer mast.

[0013] In some embodiments, an angle sensor is provided between the telescopic end of the pitching oil cylinder and the outer mast. The angle sensor is connected to the control system of the forklift truck for real-time monitoring and feedback of the tilt angle of the mast.

[0014] The beneficial effects of the present invention are as follows: There is no free lift mechanism inside the inner mast in this technical solution, which expands the driver's field of vision and improves operation safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings, where:

[0016] Figure 1 is a schematic structural diagram of a triple mast for a free lift forklift in a fully retracted state.

[0017] Figure 2 is a schematic structural diagram of a triple mast for a free lift forklift with the fork attachment lifted and the mast height unchanged.

[0018] Figure 3 This is a schematic sectional view of a three-stage mast for a forklift with free lifting according to the present invention.

[0019] Figure 4 This is a schematic cross-sectional view of a three-stage mast for a forklift with free lifting according to the present invention.

[0020] Figure 5 This is a schematic structural view of the fork-lift mast lifting and the mast in the fully lifted state of a three-stage mast for a forklift with free lifting according to the present invention. Detailed implementation manners

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] As Figures 1 to 5 shown, the embodiments of the present invention include:

[0023] A three-stage mast for a forklift with free lifting, including an outer mast 1, a middle mast 2, an inner mast 3, a free-lifting mechanism, and a mast-lifting mechanism. The outer mast 1 is fixed to the forklift frame through pin holes and a pin shaft 11, and is connected to a pitching oil cylinder 10 hinged to the frame in the middle thereof. The inclination angle of the whole mast is adjusted by the telescopic movement of the pitching oil cylinder 10. An angle sensor (not shown) is provided between the telescopic end of the pitching oil cylinder 10 and the outer mast 1, and this sensor is connected to the forklift control system to monitor and feedback the mast angle in real time.

[0024] The inner wall of the outer mast 1 is provided with a first inner guide rail, and the surface of the guide rail is treated with a wear-resistant coating; first rollers are symmetrically installed on both sides of the middle mast 2, and the first rollers are embedded in the first inner guide rail and can roll up and down along the guide rail.

[0025] The cylinder barrel of the mast-lifting oil cylinder 4 is fixed to the lower part of the outer mast 1, and the top of its piston rod is connected to the upper part of the middle mast 2. One end of the mast-lifting chain 5 is fixed to the upper part of the outer mast 1, bypasses a mast sprocket 12 installed on the upper part of the middle mast 2, and the other end is fixed to the middle part of the inner mast 3, and a tension adjusting mechanism is provided at the connection point for adjusting the chain tightness.

[0026] The inner wall of the middle mast 2 is provided with a second inner guide rail, and second rollers are symmetrically installed on both sides of the inner mast 3, and the second rollers are embedded in the second inner guide rail to ensure the stable lifting of the inner mast 3 along the middle mast 2.

[0027] An installation ear plate is provided in the middle of the middle mast 2, and the mast sprocket 12 is fixed thereto through the ear plate.

[0028] On the outer side of the inner mast 3, free lift cylinders 6 are symmetrically installed. The free lift sprocket 8 is fixed to the top of the free lift cylinder 6. One end of the free lift chain 7 is fixed to the upper top of the inner mast 3, and after passing around the free lift sprocket 8, the other end is connected to the fork 9.

[0029] The free lift cylinders 6 are symmetrically installed on the outer surfaces of both sides of the inner mast 3. The bottom of their cylinder bodies is fixed to the inner mast 3 by bolts, and the top of the piston rods is fixedly connected to the free lift sprockets 8. The telescopic direction of the piston rods is parallel to the longitudinal axis of the inner mast 3 to ensure the vertical lifting of the fork 9.

[0030] Inside the inner mast 3, a third inner guide rail is provided. Third rollers are installed on both sides of the fork 9, and the third rollers are embedded in the third inner guide rail, and the fork 9 moves up and down along the third inner guide rail.

[0031] Operating principles and combined effects of each component:

[0032] Free lift stage of the fork: When it is necessary to lift the fork 9 while keeping the height of the mast unchanged, the free lift cylinder 6 extends, pushing the free lift sprocket 8. At the same time, the free lift chain 7 passes around the free lift sprocket 8 and tightens. Under the action of the free lift chain 7, the fork 9 is pulled upward, driving the fork 9 to rise vertically along the third inner guide roller. During this process, the mast lift cylinder 4 is in the retracted state, and the middle mast 2 and the inner mast 3 remain stationary.

[0033] Overall lift stage of the mast: When the fork 9 reaches the limit height of free lift, the mast lift cylinder 4 starts to extend, pushing the middle mast 2 to rise along the first inner guide rail of the outer mast 1, and at the same time pulling the inner mast 3 to move upward synchronously through the mast lift chain 5. At this time, the inner mast 3 drives the fork 9 to further lift until the mast lift cylinder 4 is fully extended.

[0034] Descending process: When the mast lift cylinder 4 retracts, the middle mast 2 and the inner mast 3 descend along the guide rail under the action of gravity. When the mast lift cylinder 4 is fully retracted, then the free lift cylinder 6 retracts, and the fork 9 descends under the action of gravity as the chain 7 relaxes. The action sequence ensures the stability of the mast and avoids the shaking of the goods.

[0035] Overall operating principle: The present invention realizes the coordinated operation of free lift and mast lift by controlling the lifting actions of the fork 9 and the mast in stages. The free lift cylinder 6 and the mast lift cylinder 4 are independently driven. Combining chain drive and guide rail guidance ensures the smooth lifting of the fork 9 and the compact structure of the mast. The free lift cylinder 6 and the free lift sprocket 8 arranged on the outer side of the inner mast 3 avoid the occlusion of the driver's vision by the traditional free lift mechanism.

[0036] The above are only embodiments of the present invention, and do not thus limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification of the present invention, or directly or indirectly applied in other related technical fields, shall similarly be included within the patent protection scope of the present invention.

Claims

1. A three-stage mast for a forklift with free lifting, characterized in that: It includes an outer mast (1), a middle mast (2), an inner mast (3) and a fork (9); The outer mast (1) is installed on the forklift truck frame. The middle mast (2) is assembled inside the outer mast (1). The inner mast (3) is assembled inside the middle mast (2). The fork (9) is assembled inside the inner mast (3); The three-stage mast further includes a mast lifting assembly and a free lifting assembly. The mast lifting assembly includes a mast sprocket (12) and a mast lifting chain (5). The mast sprocket (12) is installed at the top position of the middle mast (2). One end of the mast lifting chain (5) is fixedly installed on the upper part of the outer mast (1). The mast lifting chain (5) bypasses the mast sprocket (12) and then fixes its other end on the inner mast (3). The mast lifting assembly further includes a mast lifting cylinder (4). The bottom of the mast lifting cylinder (4) is fixed to the lower part of the outer mast (1), and the top of its piston rod is fixedly connected to the middle mast (2); The three-stage mast further includes a free lifting assembly. The free lifting assembly includes a free lifting sprocket (8) and a free lifting chain (7). The free lifting sprocket (8) is installed at the top of the free lifting cylinder (6). One end of the free lifting chain (7) is fixed to the inner mast (3). The free lifting chain (7) bypasses the free lifting sprocket (8) and then fixes its other end on the fork (9). The free lifting assembly further includes a free lifting cylinder (6). The bottom of the free lifting cylinder (6) is installed on the inner mast (3).

2. The three-stage mast for a forklift with free lifting according to claim 1, characterized in that: Mounting lugs are provided on the middle mast (2), and the mast sprocket (12) is installed inside the mounting lugs.

3. A three-stage mast for a forklift with free lifting according to claim 1, characterized in that: The three-stage mast further includes a mast angle adjustment assembly. The mast angle adjustment assembly includes a pitching cylinder (10). The pitching cylinder (10) is hingedly installed with the forklift truck frame. The other end of the pitching cylinder (10) is hingedly connected to the outer mast (1). A pin hole and a pin shaft (11) are provided at the bottom of the outer mast (1). The outer mast (1) is assembled on the forklift truck frame through the pin hole and the pin shaft (11).

4. A three-stage mast for a forklift with free lifting according to claim 1, characterized in that: A first inner guide rail is provided inside the outer mast (1). A first roller is provided on the middle mast (2). The first roller can run along the first inner guide rail. A second inner guide rail is provided inside the middle mast (2). A second roller is provided on the inner mast (3). The second roller can run along the second inner guide rail. A third inner guide rail is provided inside the inner mast (3). A third roller is provided on the fork (9). The third roller can run along the third inner rail.

5. A three-stage mast for a forklift with free lifting according to claim 1, characterized in that: The free lifting cylinders (6) are symmetrically installed on the outer surfaces on both sides of the inner mast (3), and the telescopic direction of their piston rods is parallel to the longitudinal axis of the inner mast (3). The free lifting sprockets (8) are fixed to the tops of the free lifting cylinders (6) and are connected to the fork (9) through free lifting chains (7).

6. The triple mast for a forklift with free lifting according to claim 1 or 5, characterized in that: The cylinder barrel of the mast lifting oil cylinder (4) is fixed to the lower part of the outer mast (1), the top of its piston rod is connected to the upper part of the middle mast (2), and a tension adjusting mechanism is provided at the connection point of the mast lifting chain (5) and the upper part of the outer mast (1).

7. A three-stage mast for a forklift with free lifting according to claim 3, characterized in that: An angle sensor is provided between the telescopic end of the pitching oil cylinder (10) and the outer mast (1), and the angle sensor is connected to the control system of the forklift to monitor and feedback the inclination angle of the mast in real time.

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