JPH11322293A - Forklift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To let an operator double-check a fork condition when the operator leaves a forklift. SOLUTION: A seat switch 6 is arranged in a seat 5, while a limit switch 9 detecting whether a fork 7 is within a leaving prohibiting height or not is arranged in a mast 3. In a steering post 4, a controller 10 outputting an alarm signal if the fork 7 is at the leaving prohibiting height when the seat switch 6 is turned off, a buzzer 11 actuated by the alarm signal from the controller 10, and a display device displaying the fork condition pictographically are arranged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a forklift,
In particular, the present invention relates to a forklift having a function of prompting the user to confirm the height of the fork when the operator leaves the driver's seat while lifting the fork.

[0002]

2. Description of the Related Art In a forklift in which a fork is provided on a mast standing in front of a driver's seat so that the fork can move up and down along the mast, the forklift may stumble or hit a head.
The protruding fork tends to get in the way. Therefore, when not in use, it is desirable to keep the fork lowered to the full floor. However, when parking in parallel, as shown in FIG. 5, the spacing cannot be reduced unless the fork 7 is raised to a height that does not interfere with the preceding vehicle, and the luggage is held at a certain height. It is not always best to lower the fork down to the bottom, as a forklift may be used to keep it. Therefore, the operator decides whether to lower the fork to the bottom so that it does not get in the way or dare to lift it up to a certain height, depending on the situation, and confirms that the fork is at the optimum position. I try to get off the forklift first. It is to be noted that a model of a current forklift equipped with a switch-equipped seat (deadman seat) for detecting whether an operator is sitting in a driver seat is known.

[0003]

When a forklift is parked, when the work is temporarily stopped for urgent use,
If the attention is distracted due to the busyness, it is highly possible that the operator leaves the driver's seat without checking the status of the fork. In such a case, if the fork is at a halfway height, other work is troublesome. or,
If the lift is continued for a long time while carrying luggage on the fork, it will naturally descend, albeit slightly, and the stability of the forklift itself will not be good. In addition, since there is a possibility that the cargo may collapse, it is necessary to avoid leaving the holding place at least with the baggage loaded and lifted up.

[0004]

SUMMARY OF THE INVENTION The present invention provides a function for prompting the operator to confirm the state of a fork when the operator leaves the driver's seat and the fork is not at an appropriate height or is lifted up while carrying luggage. A first detecting means for detecting the presence or absence of an operator in a driver's seat, a second detecting means for detecting a lift-up height of the fork, and the first detecting means. If the means detects that the operator is absent from the driver's seat, it is determined whether or not the fork detected by the second detection means is at the no-prohibition height, and if the fork is at the no-prohibition height, There is provided a controller that outputs a warning signal, and a notification unit that operates a notification function in response to the warning signal from the controller. The second invention also includes a first detecting means for detecting the presence or absence of an operator in a driver's seat, a second detecting means for detecting a lift-up height of a fork, and a third detecting means for detecting the presence or absence of a load on the fork. When the detection means and the first detection means detect that the operator is not present in the driver's seat, the second and third detection means determine whether or not a load is present on the fork in the lift-up state. A controller that outputs a warning signal when the fork is lifted up while carrying luggage, and a notification unit that operates a notification function in response to the warning signal from the controller. .

In the first invention, the forbidden height is set to a range in which a person cannot pass under the fork while standing up. In the second invention, the third detecting means is provided by a hydraulic circuit for lifting and lowering the fork. Pressure sensor attached to the mast, in any of the inventions, the first detection means is a sheet switch, the second detection means is a limit switch attached to the mast, the notification means, the height of the fork The display device may display a pictograph of the sound, or may include the generation of a warning sound such as an announcement of a voice message.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a forklift according to the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the first invention. A machine seat 1 is provided with a driver's seat 2, and a pair of left and right masts 3 are provided in front of the driver's seat 2. The driver's seat 2 has a front panel
A seat 5 is provided on a rear engine cover, which is provided with an operating lever, instruments, and a steering post 4, and the seat 5 is a seat switch as first detecting means which is turned on when an operator sits down. 6 is built-in. The mast 3 is constructed by slidably attaching an inner mast 3b to an outer mast 3a, and a fork 7 is fixed to the inner mast 3b via a bracket 7a.
Are moved up and down along the mast 3 by a cylinder mechanism.

The inner mast 3b is provided with a switch operation dog 8 protruding therefrom, and the outer mast 3a is provided with a fork 7 lowered to the bottom and attached to a position away from the upper end of the dog 8 for lower limit detection. A limit switch 9 serving as second detection means, comprising a limit switch 9a and an upper limit detection limit switch 9b in which the fork 7 has a height of 2 m or more and is separated from the lower end of the dog 8; This limit switch 9
The fork 7 is turned on when the fork 7 is within the no-prohibition height between the position where the fork 7 is lowered to the bottom and touches the floor surface and the position where the fork 7 is lifted up to a height of 2 m or more, which is sufficient for a person to pass through. .

When the seat switch 6 is turned off, the steering post 4 determines from the operation of the limit switch 9 whether or not the fork is at the no-prohibition height. A controller 10 that outputs a warning signal when one of the limit switches 9a and 9b is in an ON state, and a buzzer 11 that emits a warning sound is incorporated as a notification unit that operates in response to the warning signal of the controller 10.

In the forklift thus formed, when the fork 7 is lowered to the bottom as shown in FIG. 2 or lifted up to 2 m or more as shown in FIG. Even if the user stands up and turns off the seat switch, the limit switch is not ON and no warning signal is output and the buzzer does not sound. However, if the fork is lifted to a halfway height, the limit switch is ON, and the buzzer sounds when the operator gets up from the seat, warning that the fork height is inappropriate. . The controller incorporates a program that automatically sounds an alarm if the operator sets the appropriate height by lowering or raising the fork.Also, a confirmation switch attached to the controller is provided. The alarm can also be forcibly released by pressing the button. still,
Assuming a special situation or the like in which the fork must be parked with the fork lifted up to a height of, for example, 1 m, a cancel switch may be provided in advance so as to prevent the notification means from functioning.

Although the above-mentioned embodiment has only a notification means only by a buzzer, for example, as shown in FIG.
The height of the fork can be read from the silhouette of the forklift displayed on the display device 12, and a warning sound is also given from a speaker, for example, by announcing a voice message of an electronically synthesized sound such as, for example, lowering the fork. Can be changed. In particular, if the warning sound is an announcement of a voice message, it is possible to clearly convey what the warning is. In addition to the silhouette of the forklift, pictograms such as warning texts and warning marks can be displayed on the display device.

According to the first aspect of the present invention, when the fork is at the prohibition height, the operator is prompted to confirm the height of the fork when parking. Next, it is determined whether luggage is loaded on the fork. The second invention which is one of the judgment factors of the warning signal output will be described. In FIG. 4, the same members as those of the first invention are denoted by the same reference numerals, and redundant description will be omitted. In this forklift, the limit switch 9 serving as the second detection means is a lower limit detection limit switch 9 that operates with the fork 7 lowered to the bottom.
Only a is attached. A pressure switch 14 serving as third detection means is attached to an oil feed pipe 13 that sends oil pressure to a lift cylinder in the hydraulic circuit. A detection signal from the pressure switch 14 is also input to the controller 10. . The controller 10 has a function of reading a subtle change in the load in the oil supply pipe 13 from the detection signal of the pressure switch 14 and determining the presence or absence of the load M.

With this configuration, when the load M is placed on the fork 7, if the operator leaves the driver's seat with the fork 7 lifted up, the buzzer sounds. If the controller 10 is provided with an adjusting function of determining the weight of the luggage on the fork and determining that the luggage is present, the lightweight luggage may be ignored,
It is possible to check for excessive load, and by setting a warning signal to be output if the load is small, it is possible to always lower the fork to the bottom when parking, regardless of whether there is luggage. It can also be used to ensure thoroughness. Since the pressure in the hydraulic circuit is related to the load applied to the fork, it can be said that it is extremely effective to use a pressure switch attached to the oil supply pipe to determine the presence or absence of luggage. Since no load is applied to the inside of the oil supply pipe in the installed state, the limit switch 9 can be omitted, and the second detection means can be shared by the pressure switch 14.

In each of the above embodiments, whether or not the operator is in the driver's seat is confirmed by detecting with a seat switch. However, a floor switch, a laser beam, or the like is employed as the first detecting means. A non-contact type switch may be employed as the second detecting means for detecting the height of the fork or the third detecting means for confirming the presence or absence of a load. By doing so, a warning signal is not output only when the user stands up during driving, and a warning signal is issued when the vehicle gets out of the driver's seat, so that there is little malfunction. If the first detection means is a seat switch, when the main switch (power switch for a battery type, ignition switch for an engine type) is turned off and the power of the controller is turned off at the same time, the operator will be seated. If you step down after turning off the main switch while sitting, the important warning signal will not be issued,
For example, it is desirable to set the controller to operate for at least about 10 seconds even when the main switch is turned off, and to operate only the notification function even when the main switch is turned off. On the other hand, OF controller
Delay the F operation and turn off the main switch.
The main switch can be used as the first detecting means if it is regarded as an act of the operator trying to get off the forklift. In the second invention as well, a display device can be included in the notification means, and the height of the fork lift in which the warning signal is issued in the first invention and the height of the fork to emit a warning signal in the second invention are also included in the gist of the present invention. May be appropriately changed without departing from the range.

[0014]

According to the first aspect of the present invention, if the operator attempts to leave the driver's seat with the fork lifted to a halfway position where it is likely to be in the way, the notification means works to prompt the operator to confirm. There are no mistakes. According to the second aspect of the invention, when the load is carried and left as it is lifted up, it is confirmed again whether the load is intentional, so that the left load is not left on the fork. In the first invention,
If the height of the forbidden area is set so that a person cannot pass under the fork while standing, the work is less hindered by the fork protruding from the parked forklift. If the first detection means is a sheet switch, the deadman seat attached to the existing forklift can be used, and the second detection means can be a limit switch attached to the mast, thereby facilitating the attachment. However, by using the third detection means as a pressure switch, a hydraulic circuit can be effectively used.Furthermore, by including a display device in the notification means, it becomes easy to confirm the height of the fork, By including the generation of a warning sound in the notification means, the user can be surely noticed. If the warning sound is an announcement of a voice message, it is possible to clearly convey what warning is.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of a forklift according to a first invention.

FIG. 2 is an explanatory diagram showing a state where a fork is lowered to the bottom.

FIG. 3 is an explanatory diagram illustrating a display device.

FIG. 4 is an explanatory view showing a forklift of the second invention.

FIG. 5 is an explanatory view at the time of parallel parking.

[Explanation of symbols]

1. Machine stand, 2. Driver's seat, 3. Mast, 4. Steering post, 5. Seat, 6. Seat switch,
7. Fork, 7a bracket, 8 dog,
9 Limit switch, 9a Limit switch for detecting lower limit, 9b Limit switch for detecting upper limit, 10
· · · Controller, 11 · · Buzzer, 12 · · · Display device, 13 · · · Oil supply pipe, 14 · · · Pressure switch, M · Luggage.

Claims (9)

[Claims] 1. A forklift in which a forklift is provided on a mast erected in front of a driver's seat so as to be able to move up and down along the mast, first detection means for detecting the presence or absence of an operator in a driver's seat; Second detecting means for detecting the lift-up height of the fork, and when the first detecting means detects that the operator is absent from the driver's seat, the fork detected by the second detecting means is set at a forbidden height. A forklift including a controller that determines whether or not the fork is at a forbidden height, and outputs a warning signal when the fork is at the prohibition height, and a notification unit that receives a warning signal from the controller and operates a notification function. . 2. The forklift according to claim 1, wherein the forbidden height is set in a range in which a person cannot pass under a fork while standing up. 3. A forklift in which a fork is provided on a mast erected in front of a driver's seat so as to be able to move up and down along the mast, first detecting means for detecting the presence or absence of an operator in a driver's seat; Second detecting means for detecting the lift-up height of the fork, third detecting means for detecting the presence or absence of luggage on the fork, and detecting that the operator is not present in the driver's seat by the first detecting means. In this case, the second and third detecting means determine whether or not a load is present on the fork in the lift-up state, and issue a warning signal when the fork is lifted with the load on the fork. A forklift comprising: a controller that outputs a signal; and a notifying unit that operates a notifying function in response to a warning signal from the controller. 4. The forklift according to claim 1, wherein the first detecting means is a seat switch. 5. The forklift according to claim 1, wherein the second detection means is a limit switch attached to the mast. 6. The forklift according to claim 3, wherein the third detection means is a pressure sensor attached to a fork lifting hydraulic circuit. 7. The forklift according to claim 1, wherein the notifying unit includes a display device that displays the height of the fork by pictograms. 8. The forklift according to claim 1, wherein the notification means includes generation of a warning sound. 9. The forklift according to claim 8, wherein the alarm sound is a voice message announcement.