Forklift maintenance slow-running device and forklift thereof

Abstract

The utility model belongs to the technical field of forklifts, and particularly relates to a forklift maintenance slow-running device which comprises a hydraulic system, the hydraulic system comprises an oil tank, a gear pump, a priority valve, a multi-way valve, a lifting oil cylinder, an inclined oil cylinder, a steering gear and a steering cylinder, and an oil outlet of the multi-way valve is respectively communicated with oil inlets of the lifting oil cylinder and the inclined oil cylinder. A second oil outlet CF of the priority valve is communicated with an oil inlet of the steering gear, two oil outlets of the steering gear are communicated with two oil inlets of the steering cylinder respectively, the hydraulic system further comprises a flow adjusting branch, the flow adjusting branch comprises a first speed limiting valve and an electromagnetic reversing valve, a first oil outlet EF of the priority valve is communicated with an inlet of the electromagnetic reversing valve, and a second oil outlet EF of the priority valve is communicated with an outlet of the electromagnetic reversing valve. One outlet of the electromagnetic reversing valve is communicated with an oil inlet of the multi-way valve, and the other outlet of the electromagnetic reversing valve is communicated with the oil inlet of the multi-way valve through the first speed limiting valve. According to the utility model, the maintenance function of the forklift and low-speed actions of lifting of the pallet fork and inclination of the portal frame during maintenance can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of forklifts, in particular to a forklift maintenance slow-moving device and a forklift thereof. Background Art

[0002] A forklift is an industrial handling vehicle, referring to various wheeled transport vehicles used for loading, unloading, stacking, and short-distance transport of palletized cargo. A forklift includes a hydraulic system, which is composed of a hydraulic oil tank, oil pump, oil circuit, oil cylinder, control valve, and other components. The primary function of hydraulic oil is to transfer energy, acting as a hydraulic transmission. The oil pump pumps oil into the oil circuit, which is the channel for oil to flow from the tank to the oil pump and cylinder. The oil cylinder converts the energy of the oil into mechanical energy. The control valve controls the path and flow rate of the hydraulic system's oil flow, and the hydraulic cylinder converts compressed air energy into hydraulic energy, or vice versa.

[0003] Chinese utility model patent application number CN201620877225.X discloses a forklift hydraulic system that prevents misoperation, including a hydraulic system formed by a gear pump that supplies hydraulic oil in a hydraulic oil tank to a tilt cylinder and a lifting cylinder respectively through a multi-way valve. An integrated valve is provided between the multi-way valve and the lifting cylinder, and the two oil inlets of the integrated valve are respectively connected to the oil outlet ends of the multi-way valve and the gear pump; the integrated valve is connected to the rodless cavity of the lifting cylinder in sequence through a speed limiting valve and a shut-off valve; the oil outlet of the integrated valve and the rod cavity of the lifting cylinder are both connected to the hydraulic oil tank.

[0004] In the above-mentioned forklift hydraulic system, since the multi-way valve and the tilt cylinder, as well as the integrated valve and the lifting cylinder, are directly connected by pipelines, there is no structure for limiting the mast tilt and the fork lifting speed during maintenance. Therefore, it is impossible to limit the mast tilt and the fork lifting speed during forklift maintenance, and its structure needs to be improved. Utility Model Content

[0005] In response to the shortcomings of the existing technology, the utility model provides a forklift maintenance slow-down device. By setting a flow regulating branch in the hydraulic system, when entering the maintenance mode, the normal working oil circuit is cut off, and the hydraulic oil flows through the electromagnetic reversing valve and the first speed limiting valve, and then connects to the tilt cylinder and the lifting cylinder through the multi-way valve. The forklift maintenance function and the slow movement of the fork lifting and mast tilting during maintenance can be realized. The specific technical solution is as follows:

[0006] A forklift maintenance slow-moving device includes a hydraulic system, which includes a fuel tank, a gear pump, a priority valve, a multi-way valve, a lifting cylinder, a tilting cylinder, a steering gear and a steering cylinder. The oil inlet of the gear pump is connected to the fuel tank, the oil outlet of the gear pump is connected to the oil inlet of the priority valve, the oil outlet of the multi-way valve is connected to the oil inlets of the lifting cylinder and the tilting cylinder respectively, the second oil outlet CF of the priority valve is connected to the oil inlet of the steering gear, and the two oil outlets of the steering gear are connected to the two oil inlets of the steering cylinder respectively; the hydraulic system also includes a flow regulating branch, which includes a first speed limiting valve and an electromagnetic reversing valve, the first oil outlet EF of the priority valve is connected to the inlet of the electromagnetic reversing valve, one of the outlets of the electromagnetic reversing valve is connected to the oil inlet of the multi-way valve, and the other outlet of the electromagnetic reversing valve is connected to the oil inlet of the multi-way valve through the first speed limiting valve.

[0007] Preferably, the hydraulic system further includes an oil outlet filter and an oil return filter, the oil inlet of the gear pump is connected to the oil tank through the oil outlet filter, and the oil return ports of the priority valve and the steering gear are connected to the oil tank through the oil return filter.

[0008] Preferably, the hydraulic system further includes a second speed limiting valve and a safety valve, and the oil outlet of the multi-way valve is connected to the oil inlet of the lifting cylinder through the second speed limiting valve and the safety valve in sequence.

[0009] Preferably, the oil return ports of the lifting cylinder, tilting cylinder and steering cylinder are connected to the oil tank through an oil return filter.

[0010] Preferably, a first one-way valve is provided between the second oil outlet CF of the priority valve and the oil inlet of the steering gear, and a second one-way valve is provided between the outlet of the electromagnetic reversing valve and the oil inlet of the multi-way valve.

[0011] Preferably, the forklift maintenance slow-down device further comprises a maintenance transfer switch and an electrical system, the maintenance transfer switch is electrically connected to the electrical system, the electrical system is electrically connected to the hydraulic system, and the maintenance transfer switch comprises a maintenance switch button.

[0012] Preferably, the two oil outlets of the steering gear are respectively connected to the two oil inlets of the steering cylinder through a valve block.

[0013] Preferably, a third one-way valve is provided between the oil return port of the steering gear and the oil return filter.

[0014] Preferably, the first speed limiting valve is an electromagnetic flow valve or an electromagnetic proportional valve.

[0015] The utility model also provides a forklift, which comprises the forklift maintenance slow-moving device.

[0016] The utility model provides a forklift maintenance slow-down device and a forklift thereof. Compared with the prior art, it has the following beneficial effects:

[0017] 1. The forklift maintenance slow-speed device sets a flow regulating branch in the hydraulic system and utilizes the electromagnetic reversing valve and the first speed limiting valve to realize the normal working function and maintenance function of the forklift's tilt cylinder and lift cylinder.

[0018] 2. During normal operation, after the hydraulic oil pumped by the gear pump flows into the priority valve, the hydraulic oil flowing out from the first oil outlet EF of the priority valve does not pass through the first speed limiting valve, but directly flows into the multi-way valve via the electromagnetic reversing valve, and finally enters the tilt cylinder and the lifting cylinder respectively, which can realize the normal tilting and lifting of the fork mast through the tilt cylinder and the lifting cylinder; in the maintenance state, by controlling the electromagnetic reversing valve, the hydraulic oil flowing out from the first oil outlet EF of the priority valve passes through the electromagnetic reversing valve and the first speed limiting valve into the multi-way valve, and finally enters the tilt cylinder and the lifting cylinder. By limiting the flow of hydraulic oil entering the tilt cylinder and the lifting cylinder, slow action of fork lifting and mast tilting can be achieved, avoiding the problem of maintenance personnel being squeezed by the mast and overhead guard due to the excessive speed of fork lifting and mast tilting during forklift maintenance operations.

[0019] 3. By setting the maintenance switch button, the normal working circuit of the hydraulic system can be cut off to prevent misoperation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention can be further understood from the following description in conjunction with the accompanying drawings. The components in the figures are not necessarily drawn to scale, but rather the emphasis is placed on illustrating the principles of the embodiments. In different views, the same reference numerals designate corresponding parts.

[0021] Figure 1 This is a schematic diagram of the overall structure of the hydraulic system of the present utility model;

[0022] Figure 2 This is a schematic diagram of the structural relationship between the maintenance transfer switch and the electrical system of the utility model. Figure 1 ;

[0023] Figure 3 This is a schematic diagram of the structural relationship between the maintenance transfer switch and the electrical system of the utility model. Figure 2 .

[0024] In the figure: 1. Oil tank; 2. Gear pump; 3. Priority valve; 4. Multi-way valve; 5. Lift cylinder; 6. Tilt cylinder; 7. Steering gear; 8. Steering cylinder; 9. First speed limiting valve; 10. Solenoid reversing valve; 11. Second speed limiting valve; 12. Safety valve; 13. Oil outlet filter; 14. Valve block. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with its embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0026] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of this invention are intended solely for the purpose of describing specific embodiments and are not intended to limit this invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] The "first" and "second" in the present invention do not represent specific quantities and orders, but are only used to distinguish names.

[0029] Before explaining the forklift maintenance slow-down device, a brief introduction to the existing technology is provided. A forklift is an industrial transport vehicle, also known as a cargo forklift. It generally includes a hydraulic system and an electrical system. The hydraulic system is composed of a hydraulic oil tank, oil pump, oil circuit, oil cylinder, control valve, hydraulic cylinder, etc.

[0030] When performing forklift maintenance operations (such as replacing the lifting cylinder oil seal), the hydraulic system needs to be started to complete the fork lifting and lowering, mast tilting and other actions, which poses a certain risk. At present, the forklifts on the market have only one working speed to complete the above actions, which is relatively fast, and the operator has no reaction time when encountering danger. In recent years, there have been many cases in which maintenance and operating personnel have stood on the front crossbeam of the forklift and were squeezed by the mast and overhead guard, resulting in casualties. For example, in the forklift hydraulic system for preventing misoperation disclosed in the utility model patent with application number CN201620877225.X, since the multi-way valve and the tilting cylinder and the integrated valve and the lifting cylinder are directly connected by pipelines, there is no structure for limiting the mast tilt and fork lifting speed during maintenance. Therefore, it is impossible to limit the mast tilt and fork lifting speed during forklift maintenance, and it has only one working speed.

[0031] In order to solve the problem of excessive speed during forklift maintenance, such as Figure 1 As shown, this embodiment provides a forklift maintenance slow-moving device, including a hydraulic system, which includes an oil tank 1, a gear pump 2, a priority valve 3, a multi-way valve 4, a lifting cylinder 5, a tilting cylinder 6, a steering gear 7 and a steering cylinder 8. The oil inlet of the gear pump 2 is connected to the oil tank 1, the oil outlet of the gear pump 2 is connected to the oil inlet of the priority valve 3, the oil outlet of the multi-way valve 4 is connected to the oil inlets of the lifting cylinder 5 and the tilting cylinder 6 respectively, the second oil outlet CF of the priority valve 3 is connected to the oil inlet of the steering gear 7, and the two oil outlets of the steering gear 7 are connected to the two oil inlets of the steering cylinder 8 respectively; the hydraulic system also includes a flow regulating branch, which includes a first speed limiting valve 9 and an electromagnetic reversing valve 10, the first oil outlet EF of the priority valve 3 is connected to the inlet of the electromagnetic reversing valve 10, one of the outlets of the electromagnetic reversing valve 10 is connected to the oil inlet of the multi-way valve 4, and the other outlet of the electromagnetic reversing valve is connected to the oil inlet of the multi-way valve 4 through the first speed limiting valve 9.

[0032] Specifically, the hydraulic system also includes an oil outlet filter 13 and an oil return filter. The oil inlet of the gear pump 2 is connected to the fuel tank 1 through the oil outlet filter 13, and the oil return ports of the priority valve 3 and steering gear 7 are connected to the fuel tank 1 through the oil return filter. The oil return ports of the lift cylinder 5, tilt cylinder 6, and steering cylinder 8 are connected to the fuel tank 1 through the oil return filter.

[0033] The purpose of providing the oil outlet filter 13 and the oil return filter is to filter the hydraulic oil delivered by the gear pump 2 to the priority valve 3 and the hydraulic oil flowing back to the oil tank 1 from the priority valve 3 and the steering gear 7, so as to ensure the safe and effective operation of the hydraulic system for a long time.

[0034] The first speed limiting valve 9 includes but is not limited to an electromagnetic flow valve or an electromagnetic proportional valve, which is used to limit the hydraulic oil flow from the first oil outlet BF of the priority valve 3 to the multi-way valve 4, thereby limiting the speed of the tilt cylinder 6 and the lifting cylinder 5, and finally realizing slow lifting and lowering of the fork and tilting of the mast.

[0035] The fork lifting speed in slow motion is generally not more than 0.05m / s, and the mast tilting speed in slow motion is generally not more than 0.04m / s. The fork lifting speed and mast tilting speed in slow motion can be set according to actual conditions and will not be described in detail here.

[0036] The electromagnetic reversing valve 10 may be a two-position three-way electromagnetic valve.

[0037] Compared with the existing technology, the forklift maintenance slow-speed device can realize the normal working function and maintenance function of the forklift tilt cylinder 6 and lifting cylinder 5 by setting a flow regulating branch in the hydraulic system and utilizing the electromagnetic reversing valve 10 and the first speed limiting valve 9.

[0038] During normal operation, after the hydraulic oil pumped by the gear pump 2 flows into the priority valve 3, the hydraulic oil flowing out from the first oil outlet EF of the priority valve 3 does not pass through the first speed limiting valve 9, but flows directly into the multi-way valve 4 via the electromagnetic reversing valve 10, and finally enters the tilt cylinder 6 and the lifting cylinder 5 respectively. It can realize the normal tilting and lifting of the fork mast through the tilt cylinder 6 and the lifting cylinder 5.

[0039] In the maintenance state, by controlling the electromagnetic reversing valve 10, the hydraulic oil flowing out from the first oil outlet EF of the priority valve 3 flows into the multi-way valve 4 via the electromagnetic reversing valve 10 and the first speed limiting valve 9, and finally enters the tilt cylinder 6 and the lifting cylinder 5. By limiting the flow of hydraulic oil entering the tilt cylinder 6 and the lifting cylinder 5, slow movements of fork lifting and mast tilting can be achieved, avoiding the problem of maintenance personnel being squeezed by the mast and overhead guard due to excessive speed of fork lifting and mast tilting during forklift maintenance operations.

[0040] The hydraulic system also includes a second speed-limiting valve 11 and a safety valve 12. The oil outlet of the multi-way valve 4 is connected to the oil inlet of the lift cylinder 5 through the second speed-limiting valve 11 and the safety valve 12. The safety valve 12 limits the hydraulic oil operating pressure of the lift cylinder 5, while the second speed-limiting valve 11 limits the operating speed of the lift cylinder 5.

[0041] A first one-way valve is installed between the second oil outlet CF of the priority valve 3 and the oil inlet of the steering gear 7. A second one-way valve is installed between the outlet of the solenoid reversing valve 10 and the oil inlet of the multi-way valve 4. A third one-way valve is installed between the oil return port of the steering gear 7 and the oil return filter. The provision of these first, second, and third one-way valves prevents reverse flow of hydraulic oil.

[0042] The two oil outlets of the steering gear 7 are respectively connected to the two oil inlets of the steering cylinder 8 through the valve block 14 .

[0043] Preferably, the forklift maintenance slow-down device further comprises a maintenance transfer switch and an electrical system, the maintenance transfer switch is electrically connected to the electrical system, the electrical system is electrically connected to the hydraulic system, and the maintenance transfer switch comprises a maintenance switch and a button.

[0044] When the electrical system detects that the maintenance switch has switched to the "maintenance" state, the hydraulic system is controlled by a controller such as a PLC and the normal working circuit of the hydraulic system is cut off. By setting a maintenance switch and button to cut off the normal working circuit of the hydraulic system, incorrect operation can be prevented.

[0045] In order to better prevent misoperation, such as Figure 2As shown, for a forklift with electro-hydraulic reversing, a run button, a slow up (forward tilt) button, and a slow down (backward tilt) button can also be provided in the maintenance transfer switch. The slow up (forward tilt) button and the slow down (backward tilt) button are connected in parallel and electrically connected to the electrical system. The maintenance switch is electrically connected to the electrical system and connected in series with the run button and the slow up (forward tilt) button.

[0046] After the maintenance personnel or operator presses the maintenance switch button, only by simultaneously pressing the run button and the slow up (forward tilt) button / slow down (backward tilt) button can the electrical system detect the action signal and then control the slow up and down movement of the forks and the slow forward and backward tilt movement of the mast. In this way, by setting the maintenance switch, run button, slow up (forward tilt) button and slow down (backward tilt) button, it can prevent misoperation and improve forklift operation safety.

[0047] This embodiment also provides a forklift, which includes the forklift maintenance slow-moving device.

[0048] Preferably, the forklift further comprises an inductive switch mounted on the seat or station board of the operator's cab, the inductive switch including but not limited to a micro switch and a pressure switch. Figure 3 As shown, the sensor switch can be connected in series between the run button and the slow up (forward tilt) and slow down (backward tilt) buttons. In this way, when the maintenance personnel or operator presses the maintenance switch button, if the operator leaves the seat or standing board, the sensor switch is disconnected. In the maintenance state, the forks and mast cannot move, further improving the safety of forklift operation.

[0049] The working principle of this utility model is as follows:

[0050] When the forklift is working, the gear pump 2 draws hydraulic oil and delivers it to the priority valve 3. When the forklift is not turning, the hydraulic oil flows through the flow regulating branch. When the forklift is operating normally, the hydraulic oil flows directly into the multi-way valve 4 through the electromagnetic reversing valve 10, driving the tilt cylinder 6 and the lifting cylinder 5 to operate, thereby achieving the lifting and lowering of the forks and the tilting of the mast at normal speed; after the maintenance personnel press the maintenance switch, the electrical system detects the detection signal and the forklift enters the maintenance state. At this time, the electrical system controls the electromagnetic reversing valve 10 to operate, and the hydraulic oil flows through the electromagnetic reversing valve 10 and the first speed limiting valve 9 into the multi-way valve 4, and finally enters the tilt cylinder 6 and the lifting cylinder 5. By controlling the first speed limiting valve 9 by the electrical system to limit the flow of hydraulic oil entering the tilt cylinder 6 and the lifting cylinder 5, the slow lifting and lowering of the forks and the tilting of the mast can be achieved.

[0051] When the forklift turns, most of the hydraulic oil flowing into the priority valve 3 flows into the steering gear 7 first, driving the steering cylinder 8 to move, and the remaining hydraulic oil flows into the tilt cylinder 6 and the lifting cylinder 5 through the multi-way valve, driving the forks to rise and fall and the mast to tilt.

[0052] When the operator controls the forklift mast movement through the forklift maintenance slow-down device, the electrical system simultaneously detects the maintenance signal, slow up (forward tilt) / slow down (backward tilt) signal and the induction switch signal before controlling the fork lift. That is to say, at this time, the operator needs to sit in the cab seat or stand on the platform to close the induction switch and press the maintenance switch button, the run button and the slow up (forward tilt) / slow down (backward tilt) button before controlling the fork lift, ensuring the safety of forklift operation.

[0053] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The above-described embodiments merely represent several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present utility model patent shall be determined by the appended claims.

Claims

1. A forklift maintenance slow-down device, comprising a hydraulic system, the hydraulic system including a fuel tank, a gear pump, a priority valve, a multi-way valve, a lift cylinder, a tilt cylinder, a steering gear, and a steering cylinder, the gear pump's oil inlet being connected to the fuel tank, the gear pump's oil outlet being connected to the priority valve's oil inlet, the multi-way valve's oil outlet being connected to the lift cylinder's and tilt cylinder's oil inlets, respectively, the priority valve's second oil outlet CF being connected to the steering gear's oil inlet, the steering gear's two oil outlets being connected to the steering cylinder's two oil inlets, respectively, and characterized in that: The hydraulic system also includes a flow regulating branch, which includes a first speed limiting valve and an electromagnetic reversing valve. The first oil outlet EF of the priority valve is connected to the inlet of the electromagnetic reversing valve, one of the outlets of the electromagnetic reversing valve is connected to the oil inlet of the multi-way valve, and the other outlet of the electromagnetic reversing valve is connected to the oil inlet of the multi-way valve through the first speed limiting valve.

2. A forklift maintenance slow-down device according to claim 1, characterized in that: The hydraulic system further includes an oil outlet filter and an oil return filter. The oil inlet of the gear pump is connected to the oil tank through the oil outlet filter, and the oil return ports of the priority valve and the steering gear are connected to the oil tank through the oil return filter.

3. A forklift maintenance slow-down device according to claim 2, characterized in that: The hydraulic system further includes a second speed limiting valve and a safety valve, and the oil outlet of the multi-way valve is connected to the oil inlet of the lifting cylinder through the second speed limiting valve and the safety valve in sequence.

4. A forklift maintenance slow-down device according to claim 3, characterized in that: The oil return ports of the lifting oil cylinder, the tilting oil cylinder and the steering cylinder are connected to the oil tank through an oil return filter.

5. A forklift maintenance slow-down device according to claim 4, characterized in that: A first one-way valve is provided between the second oil outlet CF of the priority valve and the oil inlet of the steering gear, and a second one-way valve is provided between the outlet of the electromagnetic reversing valve and the oil inlet of the multi-way valve.

6. A forklift maintenance slow-down device according to claim 5, characterized in that: The forklift maintenance slow-speed device further comprises a maintenance transfer switch and an electrical system. The maintenance transfer switch is electrically connected to the electrical system, the electrical system is electrically connected to the hydraulic system, and the maintenance transfer switch comprises a maintenance switch button.

7. A forklift maintenance slow-down device according to claim 6, characterized in that: The two oil outlets of the steering gear are respectively communicated with the two oil inlets of the steering cylinder through the valve block.

8. The forklift maintenance slow-down device according to claim 7, characterized in that: A third one-way valve is provided between the oil return port of the steering gear and the oil return filter.

9. The forklift maintenance slow-down device according to claim 8, characterized in that: The first speed limiting valve is an electromagnetic flow valve or an electromagnetic proportional valve.

10. A forklift, characterized in that: The forklift comprises the forklift maintenance slow-moving device according to any one of claims 1 to 9.

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