JP3657522B2 - Cargo handling vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cargo handling vehicle that performs a cargo handling operation.
[0002]
[Prior art]
A conventional cargo handling vehicle includes, for example, a low lift truck as shown in FIG. The low lift truck includes a vehicle main body 1 in which a traveling device having a traveling motor, an electromagnetic brake, a steering mechanism, and the like, a lifting device having a hydraulic cylinder (not shown), and the like are housed inside. A lever-type operation handle 2 attached to the upper part of the vehicle so as to be swingable in the front-rear direction, and a battery storage unit 3 in which a battery which is disposed on the rear side of the vehicle body 1 and serves as a driving source for the traveling device and the lifting device is stored And a pair of left and right forks 4 extending rearward from the lower portion of the battery storage portion 3. Each fork 4 is connected to a hydraulic cylinder inside the vehicle main body 1 through a link mechanism 5 disposed below the battery storage unit 3.
[0003]
A drive wheel 7 is provided below the vehicle main body 1, and a road wheel 8 is attached to the tip of each fork 4. The vehicle main body 1 and the fork 4 are connected to the road surface 9 by these wheels 7, 8. Supported on top.
[0004]
The lever-type operation handle 2 includes a steering arm 10 and an operation unit 11. The steering arm 10 is pivotally attached to the vehicle body 1 at its base end, and when this steering arm 10 is in the angle range θ1 and θ3 close to vertical or horizontal in FIG. 3, the electromagnetic brake operates. The electromagnetic brake is released when it is in the angle range θ2 between the two θ1 and θ3 (this point will be described in detail later).
[0005]
On the other hand, the operation unit 11 is provided at the tip of the steering arm 10, and as shown in FIG. 4, the operation unit 11 is for raising and lowering the accelerator lever 14 for speed adjustment and the fork 4. And switches 15 and 16 for lowering are provided.
[0006]
In the conventional low lift truck having such a configuration, after the worker M standing on the road surface 9 on the front side of the vehicle body 1 releases the electromagnetic brake by moving the operation handle 2 forward, the accelerator lever 14 of the operation unit 11 is moved. Is operated, the traveling device drives the drive wheel 7, and accordingly, the road wheel 8 is also rotated to adjust the traveling speed of the low lift truck. Further, the direction of the drive wheel 7 is changed by the left / right turning operation of the operation handle 2. Further, when the ascending and descending switches 15 and 16 are operated, the driving force of the hydraulic cylinder of the lifting device is transmitted to the fork 4 via the link mechanism 5 and the fork 4 moves up and down.
[0007]
Next, the operation and release mechanism of the electromagnetic brake accompanying the swing operation of the operation handle 2 will be described in more detail with reference to FIG.
[0008]
The steering arm 10 of the operation handle 2 has a base end portion rotatably attached to a support shaft 18 provided on a steer support 17 at a front end portion of the vehicle main body 1 and for restricting the rotational position of the steering arm 10. Abutting portions 10a and 10b that abut against the stopper bolt 20 are formed, so that the steering arm 10 can swing in a range of about 90 ° in the front-rear direction. Further, a wire spring 21 is wound around the support shaft 18, and the operation handle 2 is constantly urged to the upright side by the wire spring 21.
[0009]
Further, a cam 22 is attached to the support shaft 18 so as to rotate integrally with the steering arm 10. The cam 22 is provided with a raised portion 22a that protrudes in an arc shape in the radial direction at a part of the outer periphery thereof, and thus a stepped portion 22b is formed at a front and rear position in the circumferential direction of the outer raised portion 22a. ing.
[0010]
On the other hand, a micro switch 23 for detecting the inclination angle of the steering arm 10 of the operation handle 2 is arranged at a position close to the cam 22 of the steering support 17, and a lever 24 of the micro switch 23 is arranged on the outer periphery of the cam 22. It is configured to be in sliding contact.
[0011]
Therefore, in the configuration shown in FIG. 5, when the steering arm 10 is located within the angle range of θ2, the lever 24 of the micro switch 23 contacts the raised portion 22a of the cam 22, so that the lever 24 is pushed by the raised portion 22a. Then, the micro switch 23 is turned on. Accordingly, the electromagnetic brake of the traveling device is released, and the low lift truck can travel.
[0012]
On the other hand, when the steering arm 10 is located in the angle range of θ1 and θ3, the lever 24 of the microswitch 23 contacts the stepped portion 22b located before and after the raised portion 22a of the cam 22, so Since the pressing force 22 is lost, the microswitch 23 is turned off. In response to this, the electromagnetic brake of the traveling device is actuated to stop the traveling of the low lift truck.
[0013]
In the above description, the electromagnetic brake is turned on / off when the lever-type operation handle 2 is manually operated to swing. However, as another conventional technique, a type of reach where the operator M stands up. Some trucks have a structure in which a foot brake is provided in the vehicle body 1 and a micro switch is disposed in a link mechanism portion of the foot brake. When it is detected by the micro switch that the operator M has released the foot brake to perform the braking operation, the electromagnetic brake is operated accordingly to apply the braking.
[0014]
[Problems to be solved by the invention]
As described above, conventionally, the electromagnetic brake is turned on / off when the lever-type operation handle 2 is manually swung, or the electromagnetic brake is turned on / off by braking the foot brake. Although there is a configuration, the following problems remain in any of the conventional techniques.
[0015]
In places where cargo handling operations are performed, the road surface may be gently inclined. For example, in front of the rack mounting location, the road surface is often inclined forward toward the rack in consideration of drainage. When carrying out cargo handling work in such a place, if the electromagnetic brake is released, there is a risk that the vehicle will move freely along the slope against the operator M as soon as the load is lifted. is there. Therefore, the operator M is cautioned to always keep the electromagnetic brake activated during the cargo handling operation.
[0016]
However, since such a safe operation is left to the operator M, some operators M can ignore such warnings and still carry out the cargo handling work with the electromagnetic brake released. And it was difficult for the operator to ensure safe operation. Further, if the vehicle body moves during the cargo handling work, the stability of the vehicle body also deteriorates, and the cargo handling work in an unstable state becomes dangerous.
[0017]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a cargo handling vehicle capable of ensuring safety during cargo handling work and ensuring the stability of the vehicle body.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, the present invention employs the following configuration. That is, the cargo handling vehicle according to the first aspect of the invention includes a braking means for electrically braking the vehicle, a cargo handling work detection means for detecting the presence / absence of a cargo handling work, and a traveling operation detection for detecting the presence / absence of a traveling operation of the vehicle. And when the vehicle operation detecting means detects that the vehicle handling operation is not being carried out, and the cargo handling operation detecting means detects that the vehicle handling operation is being carried out, the vehicle is braked by the braking means, And a braking control unit that does not cause the braking unit to perform braking regardless of a detection result of the cargo handling operation detection unit when the operation detecting unit detects that the vehicle is in a traveling operation .
[0019]
Moreover, cargo handling vehicle according to the second aspect of the present invention, in the structure according to claim 1, wherein the cargo handling vehicle, characterized in that it is a low lift truck battery as a drive source.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment in the case where the present invention is applied to a low lift truck as a cargo handling vehicle will be described in detail based on the drawings.
[0021]
FIG. 1 is a block diagram of a control system for a low lift truck according to an embodiment of the present invention. Components corresponding to those of the prior art shown in FIGS.
[0022]
In FIG. 1, 14 is an accelerator lever for speed adjustment, 15 is a switch for raising the fork 4, 16 is a switch for lowering the fork 4, and 23 is turned on in response to the swinging operation of the steering arm 10 of the operation handle 2. A micro switch that turns off / on. When the micro switch 23 is turned on, this on signal is given to the controller 31 described later as a vehicle braking release command signal, and when it is turned off, this off signal is given as a vehicle braking start command signal. The configuration of each of the above parts is basically the same as that of the conventional case shown in FIGS.
[0023]
26 is a lifting device including a hydraulic cylinder (not shown) that lifts and lowers the fork 4, 28 is an electromagnetic brake as braking means for vehicle braking, 29 is a traveling motor for traveling the vehicle, and 30 is a traveling motor drive that drives the traveling motor 29. Circuit.
[0024]
31 is a controller that controls the lifting device 26, the electromagnetic brake 28, the travel motor drive unit 30 and the like based on the output signals of the accelerator lever 14, the fork lift switches 15 and 16, and the micro switch 23. Etc. Reference numeral 32 denotes a power source composed of a battery for supplying power to each unit, and 33 denotes a key switch for turning on / off the power source 32.
[0025]
The controller 31 includes cargo handling work detection means 31a, travel operation detection means 31b, and braking control means 31c. And the cargo handling work detection means 31a detects the presence or absence of the cargo handling work by the presence or absence of the signal output accompanying operation of each switch 15 and 16 for the raising / lowering of said fork 4. As shown in FIG. The traveling operation detection means 31b detects the presence or absence of a traveling operation of the vehicle based on the position of the accelerator lever 14. Further, when it is detected that the accelerator lever 14 is off and the cargo handling work is being performed by operating the switches 15 and 16, the braking control means 31c activates the electromagnetic brake 28 in response to this to operate the vehicle. Is forcibly braked.
[0026]
Next, a control procedure of vehicle braking accompanying the swing operation of the operation handle 2 will be described with reference to a flowchart shown in FIG.
[0027]
In the vehicle braking control mode, first, the controller 31 determines whether or not the microswitch 23 is on (step S1). When the micro switch 23 is not turned on, that is, when it is turned off (this means that the steering arm 10 of the operating handle 2 is located in the angle range θ1 or θ3 in FIG. 3), this off signal is used for vehicle braking. The start command signal is input to the controller 31.
[0028]
The braking control means 31c of the controller 31 operates the electromagnetic brake 28 in response to the vehicle braking start command signal (S2) to brake the vehicle. Then, it is determined whether or not the key switch 33 is turned off (S7). If the key switch 33 is not turned off, the vehicle operation is continued, and the process returns to step 1. If the key switch 33 is turned off in step 7, the power supply of the power source 32 is stopped, so that the braking control ends.
[0029]
On the other hand, when the micro switch 23 is turned on in step 1 (this means that the steering arm 10 of the operation handle 2 is located in the angle range θ2 in FIG. 3), this on signal is used to release vehicle braking. It is input to the controller 31 as a command signal.
[0030]
In response to the vehicle braking release command signal, the traveling operation detecting means 31b of the controller 31 first determines whether or not the accelerator lever 14 is in the traveling position (S3), and detects that it is in the traveling position. Then, in response to this, the braking control means 31c releases the electromagnetic brake 28 (S4). The controller 31 performs switching control of a switching element (not shown) of the traveling motor drive unit 30 in accordance with the operation of the accelerator lever 14 to adjust the power supplied to the traveling motor 29, whereby the traveling speed is controlled. Thereafter, the process proceeds to step 7 described above.
[0031]
On the other hand, when the traveling operation detecting means 31b detects that the accelerator lever 14 is not in the traveling position and the driver is not willing to drive the vehicle in step 3, the cargo handling work detecting means 31a is It is determined whether or not the switch 15 is turned on (S5). When the fork raising switch 15 is turned on, it means that a cargo handling operation is being performed, so that the braking control means 31c operates the electromagnetic brake 28 to reliably apply the braking (S2). Therefore, even if the road surface at the place where the cargo handling operation is performed is inclined, the vehicle is prevented from starting to move unexpectedly. And since the controller 31 controls the raising / lowering apparatus 26 according to operation of the switch 15 for a fork raising, the fork 4 is raised with this. Thereafter, the process proceeds to step 7 described above.
[0032]
When the fork lifting switch 15 is off in step 5, the cargo handling work detection means 31a of the controller 31 subsequently determines whether or not the fork lowering switch 16 is turned on (S6). When the lowering switch 15 is turned on, it means that a cargo handling operation is being performed, so the braking control means 31c operates the electromagnetic brake 28 to reliably apply the braking (S2). Therefore, in this case as well, even if the road surface where the cargo handling operation is performed is inclined, the vehicle is prevented from starting to move unexpectedly. And since the controller 31 controls the raising / lowering apparatus 26 according to operation of the switch 16 for fork lowering, the fork 4 is lowered | hung with this. Thereafter, the process proceeds to step 7 described above.
[0033]
When the fork raising switch 15 is turned off in step 5 and the fork lowering switch 16 is also turned off in step 6, the cargo handling operation is not being performed and the traveling operation is not being performed. The process proceeds to step 7 described above.
[0034]
In this way, even when the operator forgets to apply the vehicle braking when carrying out the cargo handling operation, the vehicle is automatically braked, so that the vehicle can be prevented from suddenly starting during the cargo handling operation. be able to.
[0035]
Referring to FIG. 2, the low lift truck in the embodiment described above releases the electromagnetic brake (S4) when the determination of whether or not the accelerator is in the traveling position (S3) is YES. This relates to a specific driving operation in the cargo handling work by the cargo handling vehicle. That is, in the cargo handling work by the cargo handling vehicle, the vehicle may start traveling while lowering the fork after scooping the load above the shelf. This is to improve the cargo handling work efficiency as much as possible. Considering this, it may be preferable to release the electromagnetic brake during the traveling operation.
[0036]
As described above, in the above-described embodiment , the microswitch 23 is used as the command signal output means for outputting the command signal for starting and releasing the vehicle braking. However, the present invention is not limited to this. A simple structure can also be used.
[0037]
Furthermore, in the above embodiment, the electromagnetic brake 28 is used as means for braking the vehicle. However, the present invention is not limited to this, and electrical braking such as regenerative braking can also be used.
[0038]
In the above embodiment , the electromagnetic brake 28 is turned on / off when the lever-type operation handle 2 is manually operated to swing. However, when the foot brake is depressed, the brake operation is performed. The present invention can also be applied to a configuration in which the electromagnetic brake is turned on / off. In this embodiment, a low lift truck has been described as an example of a cargo handling vehicle. However, the present invention is not limited to this and can be widely applied to a cargo handling vehicle such as a forklift or a transport vehicle. is there.
[0039]
【The invention's effect】
As described above, according to the cargo handling vehicle of the first aspect of the present invention, even if the operator of the vehicle forgets to apply the vehicle braking during the cargo handling operation, the vehicle braking is automatically performed. It is possible to reliably prevent the vehicle from starting unexpectedly during the movement, and also to ensure the stability of the vehicle body during the loading operation by applying braking, so that a highly safe loading operation can be realized.
[0040]
Further, according to the cargo handling vehicle of the first aspect of the present invention, the brake is activated only when the vehicle is being handled and when the vehicle is stopped, and the brake is not applied when the vehicle is being operated during the cargo handling operation. Cargo handling work can be performed while traveling, and the efficiency of cargo handling work can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram of a control system for a low lift truck according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a control procedure of vehicle braking accompanying a swing operation of an operation handle in the apparatus of FIG.
FIG. 3 is a side view showing an entire conventional low lift truck.
FIG. 4 is a plan view showing an operation portion of an operation handle of a conventional low lift truck.
FIG. 5 is a side view showing a mounting portion of a steering arm of a conventional low lift truck operation handle to a vehicle body.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vehicle main body 2 Operation handle 10 Steering arm 11 Operation part 23 Micro switch (command signal output means)
28 Electromagnetic brake (braking means)
29 travel motor 30 travel motor drive unit 31 controller (control means)
31a Handling operation detection means 31b Speed operation means 31c Braking control means

Claims (2)

Braking means for electrically braking the vehicle, cargo handling work detection means for detecting the presence / absence of a cargo handling work, travel operation detection means for detecting the presence / absence of a travel operation of the vehicle, and the travel operation detection means during the travel operation of the vehicle And when the loading / unloading work detecting means detects that the loading / unloading work is being detected, the braking means brakes the vehicle, and the traveling operation detecting means detects that the vehicle is being operated. And a braking control means for preventing braking by the braking means regardless of the detection result of the cargo handling work detection means . The cargo handling vehicle according to claim 1 , wherein the cargo handling vehicle is a low lift truck using a battery as a drive source.

Images