Automatic leveling control system and method for electric forklift

Abstract

The invention discloses an automatic leveling control system and method for an electric forklift, and the method comprises the steps: 1, turning on a trigger switch with a leveling function, and enabling the forklift to enter a leveling mode; 2, if the pallet fork is in the horizontal state, execution of the automatic leveling function is ended, and if the pallet fork is in the non-horizontal state, the step 3 is executed; 3, judging whether the movement direction of the pallet fork is consistent with the inclination direction of the pallet fork or not, if yes, executing the step 4, and if not, executing the step 5; 4, the inclination driving assembly stops working and sends out an error prompt, the driver operates the manual inclination switch again, and the step 1 is executed; 5, the inclination driving assembly drives the pallet fork to incline until the pallet fork is in the horizontal state, then the inclination assembly stops working, and automatic leveling is completed. By recognizing the inclination state of the pallet fork of the forklift and the operation state of a driver, the driver is assisted to conduct leveling rapidly, and the whole system is simple, efficient, low in cost and convenient to use.

Description

Technical Field

[0001] The invention relates to the technical field of forklifts, and in particular to an automatic leveling control system and a control method for an electric forklift. Background Art

[0002] To ensure the convenience of cargo transportation, the forks of forklifts usually have the function of tilting forward and backward. When loading and unloading cargo, the forks usually need to be tilted to a horizontal position to facilitate the forks to operate at the bottom of the cargo or the bottom of the pallet. However, it is difficult for the driver to intuitively perceive the real-time position of the forks in the driving position, which reduces the driver's work efficiency.

[0003] The automatic leveling function is currently widely used in various types of solenoid valve electric forklifts. The automatic leveling of existing electric forklifts requires the control of the solenoid valve. There are two solutions:

[0004] 1. You only need to operate the trigger switch: long press the trigger switch, the control system detects the signal, determines the fork angle, directly controls the solenoid valve to control the forward movement of the fork. When the fork reaches the horizontal position, the controller controls the solenoid valve to act again, cuts off the transmission of the tilting system, and stops the fork in the horizontal position.

[0005] 2. Need to operate the forward / rearward tilt switch: Press the trigger switch and continue to manually operate the forward / rearward tilt switch. The non-solenoid valve electric forklift cannot directly drive the tilt valve by the control device. The forward and backward tilt switches must be manually controlled to control the tilt movement of the fork. During manual operation, the operator must determine the forward and backward tilt direction of the fork. If it rotates in the reverse direction, it is considered a normal tilt operation; if it rotates in the forward direction, when the fork reaches the horizontal position, the controller controls the solenoid valve to operate, cut off the transmission of the tilt system, and stop the fork in the horizontal position.

[0006] The existing solution requires the controller to control the movement of the solenoid valve (usually a solenoid proportional valve) to control the oil circuit to achieve automatic leveling. For non-solenoid valve electric forklifts, the market demand is large, the control is difficult, and the available electrical signals are small. Since the valve movement cannot be controlled by electromagnetic means, the existing solution cannot be used to achieve it. Summary of the invention

[0007] The object of the present invention is to provide an automatic leveling control system and control method for an electric forklift to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] An automatic leveling control system and control method for an electric forklift, comprising:

[0010] A trigger switch for turning on the automatic leveling function; a tilt sensor for obtaining fork angle information; a tilting part for driving the fork to tilt forward and backward, the tilting part including a manual tilt switch and a tilt drive assembly;

[0011] The control method comprises the following steps:

[0012] Step 1. Turn on the trigger switch of the leveling function, and the forklift enters the leveling mode;

[0013] Step 2: Obtain the state of the fork through the inclination sensor. If the fork is in a horizontal state, the tilt drive component stops working and the automatic leveling function ends. If the fork is in a non-horizontal state, execute step 3;

[0014] Step 3, determine whether the moving direction of the fork is consistent with the tilting direction of the fork, if they are consistent, execute step 4, if not, execute step 5;

[0015] Step 4: The tilt drive assembly stops working and issues an error message, and the driver operates the manual tilt switch again and executes step 1;

[0016] Step 5: The tilt drive assembly drives the fork to tilt until the fork is in a horizontal state, and then the tilt assembly stops working, and automatic leveling is completed.

[0017] As a further solution of the present invention: the manual tilt switch adopts a rocker or a thumb switch or a valve stem.

[0018] As a further solution of the present invention: the tilting drive assembly includes a power device and a tilting hydraulic drive oil circuit, and the power device includes a pump motor and a hydraulic oil pump.

[0019] As a further solution of the present invention: the control system is further provided with a prompting device, and the prompting device includes sound and / or light and / or animation prompting.

[0020] As a further solution of the present invention: in step 2, the fork is provided with a front tilt tolerance angle and a rear tilt tolerance angle, and when the angle between the actual state of the fork and the horizontal state is within the front tilt tolerance angle or the rear tilt tolerance angle, it is determined that the fork is in a horizontal state.

[0021] As a further solution of the present invention: in the step 3, a front tilt limit angle and a rear tilt limit angle are set. If the fork tilt angle is between the front tolerance angle and the front tilt limit angle, the fork is determined to be in a forward tilt state; if the fork tilt angle is between the rear tolerance angle and the rear tilt limit angle, the fork is determined to be in a backward tilt state.

[0022] As a further solution of the present invention: in the step 3, if the fork is in the forward tilting device and the movement trend of the fork increases the forward tilting angle of the fork, and the fork is in the backward tilting state and the movement state of the fork is that the backward tilting angle of the fork increases, then it is determined that the movement direction of the fork is consistent with the tilting direction, otherwise it is considered that the movement direction of the fork is inconsistent with the tilting direction of the fork.

[0023] As a further solution of the present invention: if the forks are in a horizontal state in step 2, the automatic leveling function is completed, and a prompt is issued through the prompt device that the forks are in a horizontal state.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention identifies the tilt state of the forklift fork and the operating state of the driver, and simultaneously sets a leveling trigger switch; when the leveling is triggered, the detected tilt angle and tilt direction of the forklift fork are compared and judged with the manual operation of the driver, and the driver is prompted according to the judgment result, thereby assisting the driver to quickly level the fork; the overall system is simple and efficient, low in cost, and easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of the automatic leveling control system of this embodiment;

[0026] Figure 2 This is a schematic diagram of the fork state of this embodiment;

[0027] Figure 3 This is a schematic diagram for explaining the angle of the fork in this embodiment;

[0028] Figure 4 This is a logic diagram of the automatic leveling function of this embodiment; DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0030] See also Figure 1-4 ,In an embodiment of the present invention, an automatic leveling control system and control method for an electric forklift includes a trigger switch for turning on the automatic leveling function;

[0031] Inclination sensor for obtaining fork angle information;

[0032] A tilting part for driving the fork to tilt forward and backward, the tilting part includes a manual tilt switch and a tilt driving assembly, the manual tilt switch uses a rocker or a thumb switch or a valve stem, and other types of switches can also be used, as long as the forklift fork can be manually controlled to tilt forward or backward, there is no excessive restriction on this, the tilt driving assembly includes a power unit, a tilt hydraulic driving oil circuit, and the power unit includes a pump motor and a hydraulic oil pump;

[0033] Prompt device, the prompt device includes sound and / or light and / or animation prompt, but is not limited to sound, light, animation warning prompt.

[0034] The control method comprises the following steps:

[0035] Step 1. Turn on the trigger switch of the leveling function, and the forklift enters the leveling mode;

[0036] Step 2, the fork is provided with a front tilt tolerance angle and a rear tilt tolerance angle. In the present embodiment, the tolerance angle of the fork is 0.5 degrees front and rear, so that the fork can be basically in a horizontal state. At the same time, the requirement for the accuracy of the sensor is not high, and the equipment cost is greatly reduced while ensuring the function. When the angle between the actual state of the fork and the horizontal state is within the front tilt tolerance angle or the rear tilt tolerance angle, it is determined that the fork is in a horizontal state. The state of the fork is obtained by the inclination sensor. If the fork is in a horizontal state, the tilt drive assembly stops working, the automatic leveling function is terminated, and a prompt device is used to issue a prompt that the fork is in a horizontal state. If the fork is not in a horizontal state, step 3 is executed;

[0037] Step 3, set the forward tilt limit angle and the rear tilt limit angle. In this embodiment, the forward tilt limit angle of the fork is 6 degrees, and the rear tilt limit angle of the fork is 12 degrees. If the fork tilt angle is between the front tolerance angle and the front tilt limit angle, the fork is determined to be in a forward tilt state. If the fork tilt angle is between the rear tolerance angle and the rear tilt limit angle, the fork is determined to be in a rear tilt state. If the fork is in a forward tilt device and the fork movement trend increases the forward tilt angle of the fork, and the fork is in a rear tilt state and the fork movement state is that the rear tilt angle of the fork increases, then the movement direction of the fork is determined to be consistent with the tilt direction. Otherwise, it is considered that the movement direction of the fork is inconsistent with the tilt direction of the fork.

[0038] Determine whether the moving direction of the fork is consistent with the tilting direction of the fork. If they are consistent, execute step 4; if they are inconsistent, execute step 5;

[0039] Step 4: The tilt drive assembly stops working and issues an error prompt through the prompt device, and the driver operates the manual tilt switch again and executes step 1;

[0040] Step 5: The tilt drive assembly drives the fork to tilt until the fork is in a horizontal state, and then the tilt assembly stops working, and automatic leveling is completed.

[0041] In the present embodiment, since the tilt drive assembly includes an oil pump and a pump motor, when the fork needs to stop rotating, the pump motor directly stops working. Regardless of whether the fork is tilted forward or backward, the pump motor is required to drive the oil pump to increase the hydraulic pressure in the hydraulic pipeline, thereby driving the fork to rotate. In the present embodiment, the rotation and stopping of the fork are directly controlled by stopping and starting the pump motor. Regardless of whether it is a hydraulic oil circuit controlled by a solenoid valve or a hydraulic oil circuit controlled by a mechanical valve, its power source comes from the pump motor. Therefore, the present embodiment controls the rotation and stopping of the fork by controlling the pump motor, which can adapt to forklifts of various types of hydraulic oil circuits.

[0042] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0043] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description 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 may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An automatic leveling control system and control method for an electric forklift, characterized in that: include A trigger switch for turning on the automatic leveling function; a tilt sensor for obtaining fork angle information; a tilting part for driving the fork to tilt forward and backward, the tilting part including a manual tilt switch and a tilt drive assembly; The control method comprises the following steps: Step 1. Turn on the trigger switch of the leveling function, and the forklift enters the leveling mode; Step 2: Obtain the state of the fork through the inclination sensor. If the fork is in a horizontal state, the tilt drive component stops working and the automatic leveling function ends. If the fork is in a non-horizontal state, execute step 3; Step 3, determine whether the moving direction of the fork is consistent with the tilting direction of the fork, if they are consistent, execute step 4, if not, execute step 5; Step 4: The tilt drive assembly stops working and issues an error message, and the driver operates the manual tilt switch again and executes step 1; Step 5: The tilt drive assembly drives the fork to tilt until the fork is in a horizontal state, and then the tilt assembly stops working, and automatic leveling is completed.

2. The automatic leveling control system and control method of an electric forklift according to claim 1, characterized in that: The manual tilt switch adopts a rocker or a thumb switch or a valve stem.

3. The automatic leveling control system and control method of an electric forklift according to claim 1, characterized in that: The tilt drive assembly includes a power device and a tilt hydraulic oil circuit, and the power device includes a pump motor and a hydraulic oil pump.

4. The automatic leveling control system and control method of an electric forklift according to claim 3, characterized in that: The control system is also provided with a prompting device, which includes sound and / or light and / or animation prompting.

5. The automatic leveling control system and control method of an electric forklift according to claim 1, characterized in that: In step 2, the fork is provided with a front tilt tolerance angle and a rear tilt tolerance angle, and the fork is determined to be in a horizontal state when the angle between the actual state of the fork and the horizontal state is within the front tilt tolerance angle or the rear tilt tolerance angle.

6. The automatic leveling control system and control method of an electric forklift according to claim 5, characterized in that: In the step 3, a front tilt limit angle and a rear tilt limit angle are set. If the fork tilt angle is between the front tolerance angle and the front tilt limit angle, the fork is determined to be in a forward tilt state. If the fork tilt angle is between the rear tolerance angle and the rear tilt limit angle, the fork is determined to be in a rearward tilt state.

7. The automatic leveling control system and control method of an electric forklift according to claim 1, characterized in that: In the step 3, if the fork is in the forward tilting device and the movement trend of the fork increases the forward tilting angle of the fork, and the fork is in the backward tilting state and the movement state of the fork is that the backward tilting angle of the fork increases, it is determined that the movement direction of the fork is consistent with the tilting direction, otherwise it is considered that the movement direction of the fork is inconsistent with the tilting direction of the fork.

8. The automatic leveling control system and control method of an electric forklift according to claim 3, characterized in that: If the forks are in a horizontal state in step 2, the automatic leveling function is completed, and a prompt is issued through the prompt device to indicate that the forks are in a horizontal state.

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