JP2004352490A - Cargo loading/unloading operation device for forklift - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cargo loading/unloading operation device for a forklift capable of stopping a mast automatically and horizontally with excellent operation property during forward inclination operation of the mast. <P>SOLUTION: This cargo loading/unloading operation device is provided with a lever main body 42 capable of inclining, a knob 44 for finger tip operation attached rotatably to the lever main body, a detection means 52 for detecting an inclination position of the lever main body, a detection means 68 for detecting a rotation position of the knob, and a control means 54 for controlling inclination of the mast 14 based on the results of detection by these detection means. The control means stops forward inclination of the mast when the detection means 52 detects inclination of the lever main body to incline the mast forward, the detection means 68 detects rotation of the knob in the predetermined direction of rotation, and the mast is at a fork horizontal position during forward inclination of the mast. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cargo handling device for a forklift, and more particularly, to a cargo handling device for tilting a mast.
[0002]
[Prior art]
A forklift generally includes a mast attached to a front portion of a vehicle body, and a pair of forks attached to the mast via a lift bracket. The mast can be tilted back and forth with respect to the vehicle body, and a lift bracket, that is, a fork, can be moved up and down along the mast. The forward and backward tilting operation of the mast and the lifting and lowering operation of the fork are each performed by a long cargo handling lever.
[0003]
When performing a cargo handling operation with such a forklift, it often happens that it is desired to stop the fork at a position where the fork is substantially horizontal when the mast is tilted forward. For this reason, a conventional forklift is provided with a push button switch for automatically stopping the forward tilt of the mast when the fork comes to a horizontal position, and a knob of a loading / unloading lever (hereinafter, referred to as a “tilt lever”) for tilting forward and backward. (See, for example, Patent Document 1).
[0004]
In addition, from the viewpoint of improving operability, a cargo handling operation device including a small cargo handling lever that can be operated with a fingertip instead of a long cargo handling lever has been proposed. When the tilt lever in such a cargo handling operation device is provided with the above-described push button switch for automatic horizontal stop, since the lever itself is small, there is a possibility that the switch is turned on simply by touching the lever with a fingertip. . Therefore, it is conceivable that the push button switch is of an alternate type (a type in which the switch is turned on when pressed once and the switch is turned off when pressed again), and the switch is provided on a base supporting the tilt lever. Can be
[0005]
[Patent Document 1]
JP-A-9-295800
[Problems to be solved by the invention]
However, in the case of a long tilt lever, there is a possibility that the push button switch may be erroneously pressed when the tilt lever is tilted back and forth by grasping the knob with a hand. In particular, the switch is pressed during the forward leaning operation, whereas the forward leaning operation is the operation of tilting the tilt lever forward, whereas the switch is provided on the front of the knob, so the operation of pressing the switch is backward. However, there is a problem that a malfunction easily occurs.
[0007]
On the other hand, in a cargo handling operation device with a small lever, if an alternate type push button switch is provided on the base, the tilt lever and the switch are separated. It is necessary to release the finger from the lever to depress the push button switch to release the horizontal stop operation, and then to move the finger from the switch to the tilt lever again to operate it, resulting in a problem that the operation becomes complicated.
[0008]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a cargo handling operation device for a forklift capable of performing automatic horizontal stop with good operability at the time of forward leaning operation.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the cargo handling operation device for a forklift according to the present invention employs a small tilt lever operable with a fingertip from the viewpoint of operability. The lever is tiltable and rotatable. Further, the cargo handling operation device includes a first detection unit that detects a tilt position of the lever, a second detection unit that detects a rotation position of the lever, and a detection result of the first detection unit and the second detection unit. Control means for controlling the tilt of the mast based on the first detection means, wherein the control means detects that the lever has been tilted to tilt the mast forward, and the lever is moved in a predetermined rotational direction. When the fork is rotated by the second detecting means and the fork is at the horizontal position during the forward leaning of the mast, the forward leaning of the mast is stopped. Here, the horizontal position of the fork refers to the position of the mast where the upper surface of the fork is substantially horizontal when a normal fork is attached to the lift bracket.
[0010]
According to the cargo handling operation device having such a configuration, the forward tilting operation of the mast can be performed by tilting the tilt lever with a fingertip, and the automatic horizontal stop of the mast is performed by rotating the lever in a predetermined direction with the fingertip. Can be. That is, the operation of tilting the mast back and forth and stopping horizontally can be performed simultaneously.
[0011]
Further, the control means detects that the lever has been tilted to tilt the mast backward by the first detection means, and determines that the lever has rotated in the rotation direction opposite to the predetermined rotation direction. When the fork is detected, the operation of the mast may be controlled so as to stop the backward tilt of the mast when the fork is in the horizontal position during the backward tilt of the mast. Also in this case, it is possible to simultaneously perform the backward tilt operation and the horizontal stop of the mast with the fingertip.
[0012]
Furthermore, in order to facilitate the rotation operation of the lever, it is preferable to form a fingertip engaging portion for the rotation operation, such as a projection, on the lever.
[0013]
Note that the forward lean in the present specification does not only mean that the mast is tilted from the vertical state to the vehicle body front side, but tilts from the state tilted toward the vehicle body rear side from the vertical state to the vertical state. Include cases. Similarly, the term "backward leaning" as used in this specification does not only mean that the mast is tilted rearward from the vertical state to the rear of the vehicle body, but also from the state where the mast is tilted toward the front side of the vehicle body from the vertical state to the vertical state. Includes the case of tilting.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a side view showing a forklift to which a cargo handling device according to the present invention can be applied. A forklift 10 shown in FIG. 1 includes a pair of left and right masts 14 erected in front of a vehicle body 12, and a pair of left and right forks 18 attached to a front portion of the mast 14 via a lift bracket 16 (only the left side). (Shown).
[0016]
A battery (not shown) is provided inside the vehicle body 12, and the upper part of the battery is covered by a hood 20. A seat 22 on which an operator sits is provided on an upper portion of the hood 20. On the right side of the seat 22, an armrest 24 on which an operator places his / her arm is provided. The armrest 24 has a shape as shown in FIG. 2 so that the forearm portion of the arm and the palm can be placed substantially horizontally.
[0017]
The lower end of the mast 14 is supported by the axle of the front wheel 26 so as to be able to lean forward and backward. Further, a tip of a tilt cylinder 28 extending forward from the vehicle body 12 is connected to the mast 14, and the mast 14 is tilted back and forth about the axle of the front wheel 26 by extending and contracting the tilt cylinder 28. . Further, a lift bracket 16 to which a fork 18 is attached is attached to the mast 14 so as to be able to move up and down along the mast 14, and the lift bracket 16 is extended and retracted by a lift cylinder (not shown) provided on the mast 14. The fork 18 is moved up and down.
[0018]
The forward / backward tilting operation of the mast 14 and the lifting / lowering operation of the fork 18 are performed by operating the small finger-operated cargo handling levers 30, 32, 34, 36 provided on the armrest 24. These cargo handling levers 30 to 36 are arranged side by side in the left-right direction substantially at a position where a fingertip of an operator rests on the armrest 24, preferably at a front portion of the armrest 24.
[0019]
The loading lever 30 is for raising and lowering the fork 18, and the loading lever 32 is a so-called tilt lever for tilting the mast 14 back and forth. The cargo handling levers 34 and 36 are levers for attachment operation when attachments such as side shifts and rotary forks are attached to the lift bracket. Each of the cargo handling levers 30 to 36 basically includes a lever body whose lower end is supported by the armrest 24 so as to be able to tilt forward and backward, and a fingertip operation knob attached to the upper end of the lever body. I have. Reference numeral 38 denotes a rubber cover for the purpose of preventing dust from entering and improving the appearance.
[0020]
Here, the tilt lever 32 will be described with reference to FIGS. The tilt lever 32 serves as an operation input unit of the cargo handling device 40 according to the present invention, and has a function of automatically stopping the mast 14 at the horizontal position of the fork. The tilt lever 32 in this embodiment includes a substantially cylindrical lever main body 42 and a fingertip operating knob 44 attached to the lever main body 42, like the other cargo handling levers 30, 34, 36. The “lever” described in the claims refers to the tilt lever 32 including the lever body 42 and the knob 44 and the like.
[0021]
The lower end of the lever main body 42 is arranged in a concave portion 46 formed in the armrest 24. A support rod 48 is fixed to the lower end of the lever body 42 so as to penetrate substantially horizontally, and both ends of the support rod 48 are rotatably supported by support holes 50 formed in the inner wall surface of the recess 46. Thereby, the lever main body 42 can be tilted in the front-rear direction. Although not shown, the lever main body 42 is provided with a neutral position returning means such as a spring. When the finger is released from the knob 44, the lever main body 42, that is, the tilt lever 32 automatically returns to the neutral position. Then stop.
[0022]
Further, the rotation angle of the support rod 48 is detected by a potentiometer (first detection means) 52 provided on the armrest 24, whereby the tilt position of the tilt lever 32 can be detected. Has become. As shown in FIG. 4, the detection signal from the potentiometer 52 is input to a controller 54 which is a control means in the cargo handling operation device 40.
[0023]
The knob 44 is fixed to an upper end of a support shaft 58 extending from an upper end surface of the lever main body 42. The lower end of the support shaft 58 is inserted coaxially with the lever main body 42 into a concave portion 60 formed by drilling from the upper end surface of the lever main body 42, and is supported by a bearing 62 so as to be rotatable and not to move up and down. Therefore, the knob 44 is rotatable in both forward and reverse directions about the central axis of the lever main body 42 with respect to the lever main body 42. The knob 44 is not rotatable indefinitely, and its maximum rotation angle is preferably set within a range of about 10 to 40 degrees in each of the forward and reverse directions.
[0024]
In FIG. 3, reference numeral 64 denotes a spiral spring. The spiral spring 64 is a means for automatically returning the knob 44 to its neutral position. The outer end of the spiral spring 64 is fixed to the inner wall surface of the recess 60, and the inner end is fixed to the side surface of the support shaft 58. I have. Thus, when the finger is released from the knob 44, the knob 44 always returns to the neutral position and stops.
[0025]
In order to easily rotate the knob 44 with a fingertip, a protrusion (fingertip engaging portion) 66 is integrally formed on the outer peripheral surface of the knob 44. When the knob 44 is in the neutral position, as shown in FIG. 2, the protrusion 66 projects leftward from the knob 44, and pushes the rear surface forward with a fingertip, or places the fingertip on the front surface. The knob 44 can be easily rotated. As described above, since the knob 44 stops rotating at a fixed angle, for example, when the protrusion 66 is pushed forward, the tilt lever 32 tilts forward after the rotation of the knob 44 stops. It will be. Of course, by pressing the root portion (the position indicated by the symbol A in FIG. 2) of the protrusion 66, the tilt lever 32 can be tilted forward simultaneously with the rotation of the knob 44. When the force from the fingertip is made to pass through the approximate center of the knob 44 (see B in FIG. 2), only the tilt lever 32 tilts forward without rotating the knob 44.
[0026]
At the bottom of the recess 60, a potentiometer 68 as a second detecting means is provided. The potentiometer 68 detects the rotation angle of the support shaft 58 from the neutral position, and thus detects the rotation position of the knob 44. A detection signal from the potentiometer 68 is also input to the controller 54. The potentiometer 68 and the knob 44, which will be described in detail below, function as an automatic horizontal stop switch for automatically stopping the tilt when the mast 14 is at the fork horizontal position during the tilt. is there.
[0027]
Further, a signal from a horizontal detection sensor 70 such as an angle sensor or a limit switch for detecting that the mast 14 is at the horizontal position of the fork is input to the controller 54.
[0028]
Regarding the forward / backward tilting operation of the mast 14, the controller 54 controls a control valve 72, for example, a three-position spool valve in a hydraulic circuit related to the tilt cylinder 28 as shown in FIG. The tilt cylinder 28 is expanded and contracted by controlling the flow direction and flow rate of the hydraulic oil with respect to the cylinder 28. When the tilt cylinder 28 is expanded and contracted, the mast 14 is tilted back and forth about the axle of the front wheel 26 as described above.
[0029]
Next, a case where the mast 14 is tilted back and forth using the forklift 10 having the above configuration will be described.
[0030]
First, the operator sits on the seat 22 of the forklift 10 and places the forearm on the armrest 24. In this state, the operator's fingertip is at a position where the operator touches the cargo handling levers 30 to 36. In the case of a conventional forklift using a generally long cargo handling lever, the operation amount of the cargo handling lever is large, and it is substantially impossible to provide an armrest. However, in this embodiment, since the arm is supported by the armrest 24, the work It is possible to carry out cargo handling work in a comfortable posture for the person.
[0031]
When performing a normal forward tilt operation, the knob 44 of the tilt lever 32 is pushed forward with a fingertip. At this time, when the force from the finger is pushed so as to pass through the approximate center of the knob 44 (see reference numeral B in FIG. 2), the tilt lever 32 tilts forward without rotating the knob 44. When the tilt lever 32 tilts forward in this manner, the controller 54 recognizes that the tilt lever 32 has tilted forward based on a signal from the potentiometer 52 and switches the position of the control valve 72 to control and extend the tilt cylinder 28. As a result, the mast 14 leans forward about the axle of the front wheel 26. Then, when the finger is released from the tilt lever 32, the tilt lever 32 automatically returns to the neutral position, and the controller 54 returns the control valve 72 to the neutral position based on a signal from the potentiometer 52. As a result, the hydraulic oil does not flow to the tilt cylinder 28, and the forward tilting operation stops.
[0032]
Here, a description will be given of a case where the fork 18 is tilted forward from a state in which the tip of the fork 18 is directed upward, and automatically stops tilting forward when the fork reaches a horizontal position during the forward tilt. In such a case, the operator tilts the tilt lever 32 forward and rotates the knob 44 in the direction of arrow C in FIG. At this time, the tip of the protrusion 66 of the knob 44 may be pushed to cause the rotation of the knob 44 to precede the forward tilt of the tilt lever 32. However, the root of the protrusion 66 (the position indicated by the symbol A in FIG. 2) may be moved. It is desirable that the rotation of the knob 44 and the forward tilt of the tilt lever 32 be performed substantially simultaneously by pushing. Alternatively, at first, the knob 44 may be pushed at the position indicated by the reference numeral B in FIG. 2 to perform only the forward tilt of the tilt lever 32, and thereafter, the knob 44 may be rotated by changing the position of the fingertip.
[0033]
In this way, when the knob 44 is rotated in the direction of the arrow C while the tilt lever 32 is tilted forward, the controller 54 recognizes the state by the signals from the potentiometers 52 and 68 and automatically stops the horizontal movement. Set the mode. Even after the automatic horizontal stop mode is set, since the tilt lever 32 is tilted forward, the controller 54 tilts the mast 14 forward as in the normal case. When the controller 54 detects that the mast 14 has reached the horizontal position of the fork by the signal from the horizontal detection sensor 70 during the forward tilt, even if the tilt lever 32 is tilted forward, the control valve 72 is controlled. To the neutral position. As a result, the forward tilt of the mast 14 stops, and the mast 14 stops at the fork horizontal position.
[0034]
In this way, the mast 14 can be automatically horizontally stopped by simultaneously or substantially simultaneously performing the forward tilt and the rotation of the tilt lever 32 with one fingertip. Further, since a push button switch for automatic horizontal stop is not provided at a position distant from the tilt lever 32 as in the related art, it is known by those skilled in the art that the finger movement is not complicated and the operability is extremely good. It will be easily understood.
[0035]
If it is desired to continue tilting forward after the automatic horizontal stop of the mast 14, the automatic horizontal stop mode is released. To release the automatic horizontal stop mode, the knob 44 may be returned to the neutral position. This is achieved by simply moving the fingertip away from the knob 44 or changing the position of the fingertip. This will return to the neutral position. This automatic horizontal stop mode can be released even when the mast 14 is leaning forward, and the operation is very easy because the movement of the fingertip is sufficient. This is because when the operator notices that the automatic horizontal stop mode is set during the operation, the mode can be quickly released, and the erroneous operation can be prevented.
[0036]
When performing a normal backward tilt operation, the fingertip is turned to the front of the knob 44, pulled backward, and the tilt lever 32 is tilted backward. When the tilt lever 32 is tilted backward, the controller 54 recognizes that the tilt lever 32 is tilted backward by a signal from the potentiometer 52, and switches the position of the control valve 72 to shorten the tilt cylinder 28. As a result, the mast 14 tilts rearward about the axle of the front wheel 26. When the finger is released from the tilt lever 32, the tilt lever 32 automatically returns to the neutral position, the controller 54 returns the control valve 72 to the neutral position, and stops the backward tilt of the mast 14.
[0037]
The automatic horizontal stop of the mast 14 may be performed only at the time of leaning forward because the cargo can easily fall off the fork 18 at the time of leaning forward. However, in this embodiment, the tip of the fork 18 is directed downward. It also has the function of tilting backward from the facing state and automatically stopping the backward tilt when the fork reaches the neutral position during the backward tilt. In this case, the operator may tilt the tilt lever 32 backward and rotate the knob 44 in a direction opposite to the direction of the arrow C in FIG. At this time, when the fingertip is applied to the front surface of the protrusion 66 of the knob 44 and the protrusion 66 is pulled backward, the knob 44 rotates and the tilt lever 32 tilts backward.
[0038]
In this way, when the knob 44 is rotated in the direction opposite to the direction of the arrow C in a state where the tilt lever 32 is tilted backward, the controller 54 automatically adjusts the level based on the signals from the potentiometers 52 and 68. Set the stop mode. As a result, when the controller 54 detects that the mast 14 has reached the fork horizontal position by a signal from the horizontal detection sensor 70 while the mast 14 is being tilted backward as in the normal case, the control valve 72 is returned to the neutral position, and the mast 14 is stopped at the fork horizontal position.
[0039]
Thereafter, if you want to continue leaning backward or release the automatic horizontal stop while leaning backward, release your finger from the knob 44 or adjust the position of your fingertip and return the knob 44 to the neutral position. Good. Also at this time, the knob 44 automatically returns to the neutral position by the action of the spiral spring 64.
[0040]
As described above, the preferred embodiments of the present invention have been described in detail, but it goes without saying that the present invention is not limited to the above embodiments.
[0041]
For example, in the above embodiment, the protrusion is integrally formed on the knob for fingertip operation.However, in order to facilitate the rotation of the knob, as the fingertip engagement portion, a concave portion or a plurality of protrusions are formed on the outer peripheral surface of the knob. It is conceivable to form a groove or a rubber coating for preventing slippage. Further, making the knob a flat plate also facilitates the rotation of the knob.
[0042]
The means for detecting the tilt position of the tilt lever and the means for detecting the rotational position of the knob are not limited to potentiometers, but may be limit switches, encoders, or other sensors.
[0043]
Further, when an attachment having a neutral position such as a side shift or a rotary fork is attached, the cargo handling levers 34 and 36 for operating the attachment may have the same configuration as the tilt lever 32.
[0044]
In the above embodiment, the tilt lever 32 has a structure in which the knob 44 is rotatably fixed to the lever main body 42 via the support shaft 58. However, if the lever main body is capable of tilting and rotating, the knob and the lever It may have a structure in which the main body is integrated.
[0045]
【The invention's effect】
As described above, according to the forklift cargo handling operation device of the present invention, the forward tilt operation of the mast is performed by the lever tilt operation with the fingertip, and the automatic horizontal stop of the mast can be set by rotating the knob. it can. That is, the lever tilting operation and the knob rotating operation with respect to the knob can be performed by a single operation using only the fingertip, and the operability of the cargo handling operation is significantly improved.
[Brief description of the drawings]
FIG. 1 is a side view showing a forklift to which a cargo handling device according to the present invention can be applied.
FIG. 2 is a plan view showing an armrest to which a cargo handling lever as an input unit of the cargo handling operation device according to the present invention is attached.
FIG. 3 is a schematic sectional view showing a cargo handling lever for tilting the mast back and forth attached to the armrest of FIG. 2;
FIG. 4 is an explanatory diagram schematically showing a control system of the cargo handling operation device according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Forklift, 14 ... Mast, 18 ... Fork, 24 ... Armrest, 28 ... Tilt cylinder, 30, 34, 36 ... Cargo handling lever, 32 ... Tilt lever (cargo handling lever), 40 ... Cargo handling device, 42 ... Lever body, 44: knob, 52: potentiometer (first detecting means), 54: controller (control means), 66: projection, 68 ... potentiometer (second detecting means), 70: horizontal detection sensor, 72: control valve.

Claims (3)

A cargo handling operation device for operating tilting of a mast of a forklift,
A tiltable and rotatable lever,
First detecting means for detecting a tilt position of the lever;
Second detection means for detecting a rotational position of the lever;
Control means for controlling the tilt of the mast based on the detection results of the first detection means and the second detection means;
With
The first detecting means detects that the lever is tilted to tilt the mast forward, and the second detecting means detects that the lever is rotated in a predetermined rotation direction. A forklift loading / unloading device configured to stop the forward tilt of the mast when the fork is in the horizontal position during the forward leaning of the mast when is detected. The control means detects that the lever has been tilted to tilt the mast backward, and the first detection means has detected that the lever has been rotated in a rotation direction opposite to the predetermined rotation direction. 2. The forklift loading and unloading operation device according to claim 1, wherein when the fork comes to a horizontal position during the backward leaning of the mast when the second detecting means detects the backward movement, the backward leaning of the mast is stopped. . The cargo handling operation device for a forklift according to claim 1 or 2, wherein the lever is formed with a fingertip engaging portion for rotating operation.

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