Forklift and forklift control method

Patent metadata

Field	Value
Publication number	US-2016376135-A1
Application number	US-201415101117-A
Country	US
Kind code	A1
Filing date	Oct 16, 2014
Priority date	Dec 3, 2013
Publication date	Dec 29, 2016
Grant date	—

Abstract

The present disclosure relates to a forklift and a forklift control method. The forklift and the forklift control method according to the present disclosure may adjust a fork/mast inclination with reference to the coefficient of friction, and precedently and appropriately adjust a fork/mast inclination right before the forklift enters or exits from a slope by referring to geological information. Further, when a degree of danger is not decreased even when a fork/mast inclination is tilted backward to the largest extend, the forklift and the forklift control method according to the present disclosure may decrease a travelling speed of a vehicle by decreasing an output of the forklift or operating a brake, thereby remarkably decreasing the danger of the load falling.

First claim

1 . A forklift, comprising:
a forklift which is mounted with a hydraulic system and is driven by hydraulic pressure output from the hydraulic system;
a fork, on which a load or a palette is mounted;
a mast which is disposed at a front side of the forklift and elevates the fork; a tilting actuator which is disposed between the fork and the mast, and is operated by the hydraulic pressure output from the hydraulic system to adjust a degree of an inclination of the mast; an input unit, into which weight of the load, an inclination of the forklift, an inclination of the mast with respect to the forklift, an acceleration of the forklift, geological information about a travelling path, and the coefficient of static friction between the fork and the palette are input; and a control unit which calculates static friction force of the load and net force applied to the load based on each information input into the input unit to draw a degree of falling danger of the load, wherein the tilting actuator is precedently operated according to the degree of falling danger of the cargo calculated by the control unit right before the forklift enters and exits from the slope in the travelling path, so that an inclination angle of the mast is controlled.

2 . The forklift of claim 1 , further comprising:
a brake or a brake control unit which is installed in a travelling system of the forklift to brake the forklift, wherein the brake or the brake control unit is operated according to the degree of falling danger of the load calculated by the control unit, so that a speed of the forklift is controlled.

3 . The forklift of claim 1 , further comprising:
a power train or a power train control unit which is installed in a power train system of the forklift to transfer power to the travelling system, wherein the power train or the power train control unit is operated according to the degree of falling danger of the load calculated by the control unit, so that an output size of the power is controlled.

4 . The forklift of claim 1 , further comprising:
a brake or a brake control unit which is installed in a travelling system of the forklift to brake the forklift; and a power train or a power train control unit which is installed in a power train system of the forklift to transfer power to the travelling system, wherein the brake or the brake control unit is operated and the power train or the power train control unit is operated according to the degree of falling danger of the load calculated by the control unit, so that a speed of the forklift and an output size of the power are controlled.

5 . A method of controlling a forklift, comprising:
a first step, in which basic data including weight of a load, an inclination of the forklift, a fork/mast inclination, an acceleration of the forklift, geological information, and a coefficient of static friction is collected; a third step, in which static friction force by the load is calculated; a fourth step, in which sizes of the static friction force and net force applied to the load are compared and determined; a fifth step, in which when a ratio of the net force to the static friction force reaches 55%, a tilting actuator is controlled so that the static friction force is increased; a sixth step, in which updated data for the fork/mast inclination, the inclination of the forklift, and the acceleration of the forklift is collected; and a seventh step, in which sizes of updated static friction force updated by the updated data and the net force applied to the load are compared and determined, and when the updated static friction force is smaller than the net force, the method returns to the fifth step, wherein an inclination of the fork/mast is precedently controlled right before the forklift enters and exits from a slope in a travelling path.

6 . The method of claim 5 , wherein in the fifth step, when the ratio of the net force to the static friction force reaches 35% to 55%, a preliminary warning is output on a dashboard.

7 . The method of claim 5 , wherein in the fifth step, when the ratio of the net force to the static friction force reaches 45% to 65%, a visually or audibly recognizable warning message is output.

8 . The method of claim 5 , wherein in the fifth step, when the ratio of the net force to the static friction force reaches 65% to 85%, a power train or a power train control unit is controlled, so that an engine output is decreased.

9 . The method of claim 5 , wherein in the fifth step, when the ratio of the net force to the static friction force reaches 70% to 90%, a brake or a brake control unit is controlled, so that a travelling speed of the forklift is decreased.

10 . The method of claim 5 , wherein in the seventh step, when the updated static friction force is larger than the net force, the method returns to the first step.

11 . The method of claim 5 , further comprising:
a second step, in which it is determined whether there is a load, and when there is the load, the method proceeds to the third step, and when there is no load, the method returns to the first step, between the first step and the third step.

12 . The method of claim 5 , wherein the basic data further includes a definition of a danger level according to a degree of danger, and
when the degree of danger is high in the danger level, a ratio of the net force to the static friction force is set to be low, so that an operation time of the tilting actuator is controlled to be advanced, and when the degree of danger is low in the danger level, a ratio of the net force to the static friction force is set to be high, so that an operation time of the tilting actuator is controlled to be deferred.

Assignees

• Doosan Corp

Inventors

• Kim Dae Hyun

Classifications

• B66F9/0755

  Position control; Position detectors · CPC title

• B66F9/20 Primary

  Means for actuating or controlling masts, platforms, or forks (power take-off from vehicle transmissions, combined with vehicle propulsion systems B60K) · CPC title

• B66F17/003

  for fork-lift trucks · CPC title

• B66F9/14 Primary

  laterally movable, e.g. swingable, for slewing or transverse movements · CPC title