JP3900471B2 - Reach forklift - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reach-type forklift, and more particularly to an apparatus for braking the forklift .
[0002]
[Prior art]
Generally, a forklift referred to as a reach type is configured as shown in FIG. That is, the straddle arms 3 are projected and fixed to the left and right ends of the front portion of the vehicle body 2 in the forklift 1, and the mast 5 that guides the fork 4 that is lifted and lowered by the lift cylinder 13 between the straddle arms 3. It is erected to be movable.
[0003]
A driven wheel 6 is rotatably attached to the front ends of the straddle arms 3, and a single drive wheel 7 is attached to the lower part of the rear of the vehicle body 2. A caster wheel 8 is attached.
[0004]
Further, the vehicle body 2 includes a reach lever 9a for moving the mast 5 back and forth, a lift lever 9b for moving the fork 4 up and down along the mast 5, and a tilt lever 9c for adjusting the inclination of the fork 4. Various hydraulic operation levers 9 are disposed as cargo handling operation means. Further, an accelerator lever 10 is provided as an accelerator operating means for rotationally driving the drive wheels 7, and the traveling direction and traveling speed of the vehicle body 2 are determined by tilting the accelerator lever 10. Further, a steering handle 11 for steering is provided, and the direction of the drive wheel 7, that is, the so-called steering angle is controlled according to the operation of the steering handle 11 during traveling.
[0005]
A brake pedal 12 as a braking operation means operated by the driver is disposed on the vehicle body 2. The brake pedal 12 is connected to a disc brake as a mechanical braking means that locks the rotating shaft of a traveling motor that drives the driving wheel 7 and mechanically brakes the driving wheel 7. The brake pedal 12 constitutes a so-called deadman type brake. When the brake pedal 12 is depressed, the travel motor is unlocked to release the brake. When the brake pedal is depressed, the travel motor rotation shaft is locked. As a result, a braking force is applied to the drive wheels 7. Accordingly, when an abnormal situation occurs, the driver can stop the vehicle by the disc brake by removing his / her foot from the brake pedal 12.
[0006]
[Problems to be solved by the invention]
As described above, in such a reach-type forklift, for example, when carrying out a loading operation, the operator removes his / her foot from the brake pedal 12 when operating the reach lever 9a to move the mast 5 forward. If the deadman brake is applied, the vehicle body 2 does not move during that time, and stable work can be performed. However, it is troublesome to remove the foot from the brake pedal 12 and apply the deadman brake each time such a cargo handling operation is performed, so work with the foot on the brake pedal 12, that is, with the deadman brake released. May be performed. Of course, when carrying out the cargo handling operation, the vehicle does not travel actively because the accelerator lever 10 is maintained neutral, but if the mast 5 is moved while the brake pedal 12 is depressed, the mast 5 In addition, since the inertial force acts on the vehicle body 2 depending on the weight of the load on the fork 4, the vehicle body may move. At this time, depending on circumstances, when the vehicle body 2 collides with a load or a pallet, or when there is a load on the fork 4, the load collapses, which is a very dangerous situation.
[0007]
The object of the present invention is to provide a reach-type forklift that can solve such a problem and can always safely perform a cargo handling operation.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, as a first invention, a rotation detection means for detecting the rotation of a wheel, a braking means for braking the wheel, a braking operation means for operating the braking means, and an accelerator operation Accelerator operating means for performing cargo handling operation , cargo handling operation means for performing cargo handling operation, braking operation by the braking operation means and accelerator operation by the accelerator operating means are not performed, and cargo handling operation by the cargo handling operation means is performed. Braking control means for forcibly operating the braking means regardless of the operation of the braking operation means, provided that the wheel rotation detected by the rotation detection means is smaller than a predetermined value. The braking means includes mechanical braking means mechanically operated by the braking operation means and electrical braking means electrically controlled by the braking control means. It also provides a reach forklift, wherein the said braking operation means is a deadman type brake operating means for braking in the absence of depression of releasing the brake the brake pedal when there is depression of the brake pedal To do.
[0009]
According to the first aspect, movement of the vehicle body during cargo handling work is prevented, and safe and secure work is guaranteed. Therefore, in the first aspect of the invention, the predetermined value when “the rotation of the wheel is smaller than the predetermined value” is an extremely small value that does not correspond to the traveling of the vehicle, and even if the wheel moves slightly, the entire vehicle body Is a value that can be said to be substantially stopped, and is a value that means that it is not necessarily zero. Moreover, the above-mentioned conditions are the minimum conditions, and it is a matter of course that other conditions can be added thereto. Further, according to the first aspect of the invention, it is possible to prevent the braking operation by the braking operation means and the braking control by the braking control means from being overlapped, which is efficient, and the operation time of the braking control means is shortened to the minimum necessary time. And has the effect of improving durability.
[0010]
As a second invention, there is provided a cargo handling vehicle according to the first invention, wherein the braking control means operates the braking means when the condition is satisfied for a predetermined time.
[0011]
According to the second aspect of the invention, since it is confirmed that the “state requiring braking” in the first aspect of the invention is surely present, the braking means is operated suddenly against the will of the operator. Can be avoided. Therefore, according to the second aspect of the invention , safe cargo handling work is more reliably ensured. Accordingly, the “predetermined time” in the second aspect of the invention is preferably set as a time required from when the vehicle body substantially stops until the cargo handling operation is started. A value between seconds is set.
[0012]
According to a third aspect of the present invention, in any one of the first and second aspects of the invention, when the condition is not satisfied during braking by the braking control unit, the braking by the braking control unit is released. Provide a vehicle.
[0013]
According to the third aspect of the invention , for example, when the operator finishes the cargo handling work and operates the accelerator operation means, the braking is automatically released and the vehicle body can be traveled. it can.
[0014]
The first to third inventions described above can be implemented in various forms depending on the embodiment. The present invention described above includes all of these forms without departing from the spirit of the present invention.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. The basic configuration of the reach-type forklift in this embodiment is the same as that shown in FIG. 3, and will be described below with reference to FIG.
[0016]
In the reach type forklift 1 in this embodiment, the control device is configured as shown in FIG. That is, a rotation sensor 21 serving as a rotation detection unit is provided on the axle of the drive wheel 7, and the rotation sensor 21 detects the rotation speed or rotation speed of the drive wheel 7. The brake pedal 12 provided in the driver's seat and the sensor or micro switch for detecting the operation constitute a deadman brake switch 22 as a braking operation means that is turned on / off by a depression operation of the pedal 12, and this deadman brake switch Based on the state of 22, the presence or absence of depression of the brake pedal is detected.
[0017]
The accelerator lever 10 provided on the operation panel in front of the driver's seat and the micro switch for detecting the operation constitute an accelerator lever switch 23 as an accelerator operating means that is turned on / off by the tilting operation of the lever 10. Based on the state of the accelerator lever switch 23, the presence or absence of the operation of the accelerator lever 10 is detected. Further, the reach lever 9a provided in the vicinity of the accelerator lever 10 and the micro switch for detecting the operation constitute a reach lever switch 24 as one of the cargo handling operation means that is turned on / off by the tilting operation of the lever 9a. Based on the state of the reach lever switch 24, whether or not the reach lever 9a is operated is detected.
[0018]
Further, the reach type forklift 1 is provided with a driven wheel brake 26 as a braking means comprising an electromagnetic brake for braking the driven wheel 6, and braking control from the CPU 27 corresponding to the braking control means provided inside the vehicle body. The driven wheel brake 26 is controlled by a signal.
[0019]
The CPU 27 takes in the outputs of the rotation sensor 21, deadman brake switch 22, accelerator lever switch 23, and reach lever switch 24, and detects whether or not the vehicle body 2 has been stopped for a predetermined time, When it is determined that the vehicle body 2 has been stopped for a predetermined time, the CPU 27 outputs a braking control signal to the driven wheel brake 26 to operate the driven wheel brake 26 and forcibly control the driven wheel 6. The vehicle body 2 is held in a stopped state.
[0020]
The CPU 27 determines whether the vehicle body 2 is in a stopped state.
[1] When rotation of the drive wheel 7 is not detected by the rotation sensor 21
[2] When the brake pedal 12 is depressed from the state of the deadman brake switch 22, that is, when the release of the deadman brake is detected,
[3] When no operation of the accelerator lever 10 is detected from the state of the accelerator lever switch 23,
[4] When the operation of the reach lever 9a is detected from the state of the reach lever switch 24,
If all the four stop conditions are satisfied, it is determined that the vehicle body 2 is in a stopped state.
[0021]
When the CPU 27 determines that the vehicle body 2 is in the stopped state, the CPU 27 starts the timer 29 and starts counting for a predetermined time set in advance. When the timer 29 counts up, the CPU 27 starts the driven wheel brake 26. A braking control signal is output at
[0022]
If any one of the above four stop conditions is not satisfied during forced operation of the driven wheel brake 26, the output of the braking control signal from the CPU 27 to the driven wheel brake 26 is stopped, and the driven wheel brake 26 Forced operation is released.
[0023]
Next, the processing procedure of the forced operation of the driven wheel brake 26 will be described with reference to the flowchart of FIG. As shown in FIG. 2, the CPU 27 captures the output of the rotation sensor 21 (S1), and captures the states of the deadman brake switch 22, the accelerator lever switch 23, and the reach lever switch 24 (S2) for driving. It is determined whether or not the wheel 7 is not rotating (S3). If the determination result is YES, it is determined that the stopping conditions [1], [3], and [4] are satisfied.
[0024]
Subsequently, it is determined whether or not the deadman brake is released (S4). If the determination result is YES, it is determined that the stop condition [2] is satisfied. Then, the process proceeds to the next step S5, where it is determined whether or not the accelerator lever 10 is operated (S5). If the determination result is YES, it is determined that the stop condition [3] described above is satisfied, the process proceeds to the next step S6, and it is determined whether or not the reach lever 9a is operated (S6).
[0025]
If the decision result in the step S6 is YES, it is judged that the above stop condition [4] is satisfied, and the timer 29 is started assuming that all four stop conditions are satisfied (S7). Next, it is determined whether or not the timer 29 has been counted up (S8). If this determination result is NO, this determination is repeated until the determination result is YES. A braking control signal is output to the driving wheel brake 26, the driven wheel brake 26 is forcibly operated (S9), the vehicle body 2 is held in a stopped state, and the process returns to the start. Note that the count up of the timer 29 in this step (S8) needs to be set to a very short time until the inertial force is applied to the vehicle body by the start of the operation of the reach lever in the above step (S6). Therefore, in this case, this time may be set to zero and the steps (S7) and (S8) may be omitted.
[0026]
On the other hand, if the determination result of steps S3, S4, S5, and S6 described above is NO, the process proceeds to step 10 and it is determined that one of the four stop conditions is not satisfied. At this time, the output of the braking control signal from the CPU 27 to the driven wheel brake 26 is stopped, the forced operation of the driven wheel brake 26 is released, the timer 29 is reset (S11), and then the process returns to the start.
[0027]
Therefore, according to the above-described embodiment, when the reach operation is performed, the driven wheel brake 26 is automatically set without the operator placing his / her foot on the brake pedal 12, that is, without applying the deadman brake. The vehicle is forcibly actuated and the vehicle is stopped. Therefore, it is possible to prevent the vehicle body 2 from unexpectedly moving due to the inertial force accompanying the reach operation, and to perform the reach operation in a stable state.
[0028]
Note that the present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.
[0029]
For example, in the above-described embodiment, the mechanical braking means is provided on the driving wheel 7 and the electrical braking means is provided on the driven wheel 6 as the braking means, but both of them may be provided on the driving wheel 7, for example.
[0030]
【The invention's effect】
As described above, according to the present invention, the vehicle body is prevented from moving during the cargo handling operation, so that it is safe, and since it is not necessary to perform a brake operation during the cargo handling operation, an efficient cargo handling operation is guaranteed.
[Brief description of the drawings]
FIG. 1 is a block diagram of a control device according to an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of the embodiment of the present invention.
FIG. 3 is a perspective view of a reach type forklift as a background of the present invention.
[Explanation of symbols]
1 Reach-type forklift (loading vehicle)
2 Car body 4 Fork 6 Driven wheel 7 Drive wheel 9a Reach lever 21 Rotation sensor (Rotation detection means)
22 Deadman brake switch (braking operation means)
23 Accelerator lever switch (accelerator operation means)
24 Reach lever switch (Handling operation means)
26 Driven wheel brake (braking means)
27 CPU (braking control means)
29 Timer

Claims (3)

Rotation detecting means for detecting the rotation of the wheel, braking means for braking the wheel, braking operation means for operating the braking means, accelerator operating means for operating the accelerator, and cargo handling operation for performing the cargo handling operation And the braking operation by the braking operation means and the accelerator operation by the accelerator operation means are not performed, the cargo handling operation by the cargo handling operation means is performed, and the wheel detected by the rotation detection means Braking control means for forcibly operating the braking means regardless of the operation of the braking operation means on condition that the rotation is smaller than a predetermined value, and the braking means is mechanically operated by the braking operation means. Mechanical braking means and electrical braking means electrically controlled by the braking control means. Reach forklift, characterized in that to release the brake is a deadman type brake operating means for braking in the absence of depression of the brake pedal when there is write. The reach type forklift according to claim 1, wherein the braking control unit operates the braking unit when the condition is satisfied for a predetermined time. 3. The reach-type forklift according to claim 1 , wherein when the condition is not satisfied during braking by the braking control means, braking by the braking control means is released.

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