JP2004277084A - Pallet locking device of forklift - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pallet locking device of a forklift capable of automatically locking a pallet and capable of detecting an imperfect locking state where contact pressure of a locking bar becomes short or zero. <P>SOLUTION: This pallet locking device of the forklift pressurizes the locking bar 14 at a locking position through an elastic means 26 by actuating a driver 18 when it detects the pallet 40 into which a fork 6 is inserted in a state where the locking bar 14 is positioned at an unlocking position and stops and locks the driver 18 when elastic deformation quantity of the elastic means 26 detected by a deformation quantity detection means 31 becomes a specified value. Thereafter, it detects the imperfect locking state by detecting that the elastic deformation quantity of the elastic means 26 decreases by the deformation quantity detection means 31. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pallet lock device provided on a forklift for locking a pallet inserted into a fork.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a forklift in which an operator transfers to a pallet lifted from a loading surface with a fork, such as an order picking truck, and unloads the load, the center of gravity of the load depends on the loading and unloading of the load and the position of the operator on the pallet. Since the position fluctuates, a pallet lock device for fixing the pallet supported by the fork to the fork is provided in order to prevent the pallet from tilting, skidding, or swinging due to the fluctuation of the load center of gravity.
[0003]
An example of the pallet lock device is disclosed in the following patent document.
[Patent Document 1]
JP-A-11-228085
[Patent Document 2]
JP-A-10-291790
[Patent Document 3]
JP 2001-316095 A
[Patent Document 4]
JP 2002-12397 A
[0004]
[Problems to be solved by the invention]
All of the pallet lock devices described in these documents are manually operated, and it is not possible to eliminate forgetting to operate the pallet lock device. For this reason, the inventor of the present invention has considered that the pallet is automatically locked by the driving device, but in this case, a measure is required to cope with an operation error of the device. In particular, when the operation of the pallet lock device is insufficient and locking cannot be reliably performed, it is necessary to reliably determine this and return to the original state to solve the problem.
[0005]
The present invention has been proposed from such a viewpoint, and an object of the present invention is to provide a device which can automate a pallet locking device, not a conventional manual type, and can reliably perform locking.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a lock bar movably provided between a lock position for locking a pallet and an unlock position for releasing a lock, and pallet detection means for detecting a pallet inserted into a fork. An elastic means for setting the contact pressure of the lock bar to the pallet at the lock position, a driving device for driving the lock bar to the lock position via the elastic means, and a pressure detection for detecting the urging force of the elastic means Means or a deformation amount detecting means for detecting an elastic deformation amount, and a control circuit, wherein the control circuit detects the pallet inserted into the fork in a state where the lock bar is located at the release position by the pallet detecting means. The drive unit is operated to move the lock bar to the lock position, and thereafter, the elastic means presses the lock bar against the pallet with a predetermined pressure. When the pressure detection means or the deformation amount detection means detects that the fork is being lifted, the driving machine is stopped, and thereafter, the pressure of the elastic means is detected by the pressure detection means while the rise of the fork is detected by the rise detection means. A pallet lock device for a forklift, wherein an incomplete lock state is detected by detecting a decrease or a decrease in the amount of deformation of the elastic means by the deformation amount detection means.
[0007]
According to this, when the pallet in which the fork is inserted is detected by the pallet detecting means in a state where the lock bar is located at the release position, the driving device operates to move the lock bar to the lock position, and thereafter, the elastic By stopping the driving means in a state where the means presses the lock bar against the pallet with a predetermined pressure, an effect of terminating the locking operation can be obtained.
[0008]
Further, according to the present invention, when the fork is raised after the locking operation is completed, the pressure detecting means detects a decrease in the pressure of the elastic means or the deformation amount detecting means detects a decrease in the deformation amount of the elastic means. Accordingly, an effect that an incomplete lock state is detected can be obtained.
[0009]
In the present invention, when the control circuit detects an incompletely locked state, if an alarming means is provided for notifying the operator of the incompletely locked state, the alarming means is activated when the incompletely locked state is reached, and the operator is not notified. It is notified that it is in the completely locked state.
[0010]
By the way, in the present invention, the release position of the lock bar may be any position that does not hinder the insertion and removal of the fork from the pallet. For example, the release position may be set outside the plane contour of the pallet supported by the fork, It can be set to the same height as the fork inside.
Here, the height equivalent to the fork means not only the area between the upper surface and the lower surface of the fork, but also includes a range equal to or lower than a predetermined height from the upper surface of the fork and a range equal to or higher than a predetermined height from the lower surface of the fork. For example, in order to detect that the pallet is placed on the fork by moving with the weight of the pallet placed on the fork, a part of the pallet is set at a position protruding above the upper surface of the fork.
[0011]
In the present invention, the lock position of the lock bar includes a position in contact with the upper surface of the upper deck board of the pallet and a position in contact with the upper surface of the lower deck plate of the pallet.
[0012]
Further, in the present invention, the pallet detecting means may be configured to simply detect a pallet into which a fork is inserted. However, in order to prevent occurrence of an incompletely locked state, the pallet detecting means is inserted into the pallet. It is preferable that the upper deck plate that is in contact with the upper surface of the fork can be detected.
[0013]
The pallet detecting means may be provided at a predetermined height from the running surface of the forklift, but the pallet into which the fork is inserted is supported by a member that accompanies the fork such as a lift bracket supporting a fork, a driver's cab, and the like. Detects whether the upper deck plate is in contact with the upper surface of the fork inserted into the pallet, regardless of the difference in the height of the loaded loading surface and the height of the pallet into which the fork is inserted. It is more preferable to configure.
[0014]
In the present invention, when the pallet detecting means is configured to detect an upper deck board of a pallet abutting on an upper surface of a fork, when the control circuit detects an incompletely locked state, the drive circuit is operated in reverse. When the lock bar is returned to the release position by moving the lock bar to the release position, the incomplete lock state is released and the fork inserted into the pallet contacts the upper deck plate of the pallet. Thus, it is possible to obtain an effect that the lock operation for driving the lock bar to the lock position is repeated.
[0015]
As the pallet detecting means, switches such as a microswitch and a proximity switch, sensors such as a pressure sensor, a magnetic sensor, and an optical sensor, and passive components such as a potentiometer are used.
[0016]
The drive unit may be configured to move the lock bar from a release position that does not hinder insertion and extraction of the fork to a lock position that abuts on the fork, and has a function of returning the lock bar from the lock position to the release position. May be provided, or may not have this function.
[0017]
In the case of using a drive unit that does not have a function of returning the lock bar from the lock position to the release position, for example, a release urging unit that returns the lock bar from the lock position to the release position may be provided.
[0018]
The elastic means may be configured so as to press the lock bar located at the lock position under the control of the driving device against the pallet with a predetermined pressure, for example, a lock between the driving device of the driving means and the lock bar. What is necessary is just to comprise by the excessive operation | movement absorption spring provided in order to absorb the excessive operation | movement of the drive with respect to a bar, for example, to comprise a compression coil spring, a tension coil spring, a helical coil spring, a spiral spring, etc.
[0019]
The driving device only needs to convert driving energy such as fuel, electricity, and fluid pressure into a mechanical operation. If necessary, the mechanical operation of the driving device is mechanically applied to a lock bar through an elastic means. It has an interlocking mechanism for transmitting to
[0020]
An internal combustion engine may be used as the driving device, but in order to prevent noise and air pollution, an electric device driven by electricity or a hydraulic device driven by pressure oil supplied from an electric hydraulic pump is used. Preferably, an apparatus is used.
[0021]
Here, the electric device includes an electric cylinder, an electric motor (motor), and the like, and the hydraulic device includes a hydraulic cylinder, a hydraulic motor, and the like.
[0022]
The lift detecting means may be constituted by, for example, a potentiometer, a rotary encoder, or the like for detecting the ascent operation itself of the fork, and an operating tool such as a lift lever operated to raise the fork is operated in the ascending direction. A micro switch, a potentiometer, a rotary encoder, and the like for detecting the fact may be used.
[0023]
The control means first detects the pallet into which the fork has been inserted by the pallet detection means, and based on the detection result, activates a driving device to move the lock bar to the lock position, and detects the pressure detection means or the deformation amount detection. When the means detects that the pressure of the elastic means is a predetermined value, the driving device is stopped and the lock bar is pressed against the pallet with a predetermined contact pressure.
[0024]
Further, the control means may detect that the fork has been raised by the lift detection means after the lock state in which the lock bar is pressed against the pallet with a predetermined pressure at the lock position is detected. By judging the presence or absence of a decrease in the pressure or the amount of elastic deformation of the elastic means, it is configured to detect whether or not the lock is incomplete, such as a microcomputer or a sequencer incorporating an appropriate control program. Is used.
[0025]
By the way, in the present invention, in order to prevent the collapse of the load and to ensure the safety of the operator on the pallet, the lock state in which the pallet is fixed to the fork by the lock bar is not released until the pallet is placed on the loading surface. After the pallet is placed on the loading surface, it is more preferable that the fork is not released until the fork is lowered to the rack detection position which has been lowered from the upper deck board by a predetermined distance or more.
[0026]
In the present invention, since the drive unit is configured to drive the lock bar via the elastic means, the urging force of the elastic means is set to be weaker than the downward driving force of the fork, so that the lock bar is prevented from being driven. The fork can be lowered to the rack detection position without being locked, and the lock bar and the driving means can be prevented from being deformed or damaged, and the locked state is maintained until the fork lowers the fork to the rack detection position. I try to make it.
[0027]
Then, when the pallet is placed on the loading surface, and the pressure of the elastic means or the increase in the amount of elastic deformation which is increased by lowering the fork from the upper deck board by a predetermined distance or more is detected by the pressure detecting means or the deformation amount detecting means. By configuring the control circuit to start the reverse operation of the drive, the release operation to release the locked state with the pallet securely placed on the loading surface can be started, and the operator can load the pallet. It is possible to eliminate the mistake of releasing the locked state before lowering on the surface.
[0028]
When the reverse operation of the driving machine is started, first, the excessive operation of the driving machine with respect to the lock bar is eliminated by the elastic restoring property of the elastic means, and thereafter, the lock bar moves toward the release position in conjunction with the driving machine. I do.
[0029]
The reverse operation of the driving machine is continued until the lock bar returns to the release position, and is stopped when it is detected that the lock bar has returned to the release position. Thereafter, the lock bar is urged by the release urging means to release the lock bar. Held in position.
[0030]
As a result, as long as the fork is not inserted into the pallet next time, or the fork is inserted into the pallet and not raised to the pallet detection position, the lock bar is held in the release position, and the fork is pulled out of the pallet, and then the pallet is further inserted into the pallet. When the fork is inserted, the lock bar does not come into contact with the pallet, thereby preventing the pallet from being damaged or causing the load to collapse.
[0031]
In the present invention, the control circuit may be provided with an error detecting section for detecting an error in each section of the control circuit or a control error. Further, when an error is detected by the error detection unit, an alarm is given to an operator, and when a serious error that leads to breakage of the pallet lock device is detected, the operation and reverse operation of the driving means are prohibited. , The operation of only the driving means may be prohibited when the error is detected.
[0032]
It is detected that a serious error has occurred such as a malfunction of the driving means or the lock bar which may be deformed or damaged due to malfunction of the FET used for determining whether the detected value is equal to or greater than a predetermined threshold value. If the operation and the reverse operation of the driving means are prohibited in this case, the lock bar and the interlocking mechanism for interlocking the lock bar with the driving device due to the driving force of the driving device can be prevented from being deformed or damaged.
[0033]
When other errors occur, only the operation of the driving means is prohibited, and if the reverse operation is permitted, the pallet is lowered to the loading surface and the fork is lowered to the rack detection position. The bar can be moved to the release position and the fork can be withdrawn.
[0034]
The present invention is applied to an order picking truck as described below. However, the present invention is not limited to this, and a forklift is used by an operator to load and unload cargo on a pallet supported by a fork and to steer. Widely applicable to.
[0035]
In addition, the present invention is not limited to a pallet lock device built into a newly built vehicle, but also includes a pallet lock device as an optional component to be retrofitted to a ready-made vehicle, and a pallet lock device as a modified part.
[0036]
BEST MODE FOR CARRYING OUT THE INVENTION
A pallet lock device for a forklift according to an embodiment of the present invention will be specifically described below with reference to the drawings. 1 is a side view of a pallet lock device of a forklift according to an embodiment of the present invention, FIG. 2 is a plan view of the pallet lock device, and FIG. 3 is an order picking truck including the pallet lock device. FIG.
[0037]
As shown in FIG. 3, the order picking truck includes a mast 4 at a rear portion of a vehicle body 3 that travels on a running surface by three wheels of a drive wheel 1 and left and right road wheels 2. A driver's cab 5 and left and right forks 6 supported to move up and down along with the other are provided.
[0038]
Corner pillars 7 are erected at both left and right corners of the front of the cab 5, and a steering panel including a steering wheel, a lifting control operating tool, a traveling control operating tool and the like is supported at an intermediate height of the both corner pillars 7. A head guard 8 is supported at the upper end of each corner post 7. The deck 9 of the cab 5 is provided with, for example, a deadman type brake pedal, and the left and right forks 6 are fixed to the lower surface of the cab 5.
[0039]
As shown in FIGS. 1 and 2, a pallet lock device 10 according to one embodiment of the present invention is provided between the left and right forks 6 below the deck 9 of the cab 5. I have.
[0040]
The pallet lock device 10 includes a base plate 11 supported by the driver's cab 5, a support shaft 13 supported at the rear end of the base plate 11 via left and right brackets 12, and a support shaft 13 mounted on the support shaft 13. It has left and right lock bars 14 rotatably supported around the center, that is, around the left and right axes.
[0041]
Here, the left and right lock bars 14 are connected to each other by a connection frame 15 at an intermediate portion thereof, so as to rotate around the support shaft 13 in synchronization.
[0042]
Further, the pallet lock device 10 includes a driving means 16 for driving the left and right lock bars 14 in the locking operation direction. The driving means 16 has a front end pivotally supported by the base plate 11 via a shaft 17. A drive unit 18 including an electric cylinder and an output unit of the drive unit 18, that is, a link mechanism 20 connected to a piston rod 19 are provided.
[0043]
FIG. 4 is a plan view of the link mechanism 20. As shown in FIGS. 1 and 4, the link mechanism 20 has a lower end supported by the base plate 11 so as to be rotatable around a left-right axis. A first link arm 21 whose portion is connected to the piston rod 19, and a lower end portion is rotatably supported by the base plate 11 about a left-right axis, and an intermediate portion or an upper end portion receives the connection frame 15 from the front. There is provided a second link arm 22 and an excess operation absorbing mechanism 23 for connecting an intermediate portion of the first link arm 21 to an upper end of the second link arm 22.
[0044]
The excess operation absorbing mechanism 23 has a shaft 24 whose front end is rotatably connected to an intermediate portion of the first link arm 21 so as to be rotatable around the left and right axes, and a rear end of the shaft 24 is movable in the axial direction. And a bracket 25 which is connected to the upper end of the second link arm 22 so as to be rotatable around the left-right axis, and a compression coil spring for urging the bracket 25 toward the rear end of the shaft 24. Elastic means 26 for absorbing excessive movement of the shaft 24 with respect to the bracket 25.
[0045]
On the other hand, the lock bar 14 is urged in a direction (release direction) in which the connecting tool 16 is pressed by the second link arm 22 by the release urging means 27 which is stretched over the connecting frame 15 and the base plate 11. I have.
[0046]
As shown in FIG. 1, the lock bar 14 is formed in an arrowhead shape with a rounded rear end, and in a free state in which the pallet 40 is not placed thereon, the lock urging means 27 and the driving means 16 are used. The intermediate portion protrudes from the upper surface of the fork 6, and the lower surface is held at a release position where the lower surface is slightly higher than the lower surface of the fork 6 and is located horizontally.
[0047]
FIG. 5 is a side view of the pallet lock device 10 in a state where the fork 6 inserted into the pallet 6 is raised to a pallet detection position where it contacts the upper deck plate 41, and the urging force of the release urging means 27 is When the fork 6 rises to a level where it comes into contact with the lower surface of the upper deck board 41, the lock bar 14 is biased by the weight of the pallet 40 as shown in FIG. It rotates in the direction of the lock position against the biasing force of the means 27.
[0048]
By the way, as shown in FIGS. 1 and 4, a pallet detecting means 32 composed of, for example, a magnetic sensor for detecting that the lock bar 14 has moved below the upper surface of the fork 6 is provided on the base plate 11 via a bracket 42. Supported.
[0049]
A driving piece 43 made of a magnet for driving the pallet detecting means 32 is supported by the lock bar 14 via the arm 44 and the connection frame 15, and as shown in FIG. The driving piece 43 separates from the pallet detecting means 32 when the pallet detecting means 32 is pushed down to the height of the pallet, so that the pallet detecting means 32 is switched, for example, from on to off.
[0050]
As a result, the operation mode is switched from the free mode to the lock operation mode, the drive unit 18 is started, and the second link arm 22 catches up with and abuts on the connection frame 15, and then the piston rod 19 and the first link arm 21. When the shaft 24 excessively moves by the lower limit value A with respect to the bracket 25 and the second link arm 22, the urging force of the elastic means 26 increases to overcome the urging force of the release urging means 27, and the second link arm 22 is connected. The lock bar 14 is driven toward the lock position via the frame 15.
[0051]
However, the lock bar 14 may be driven to the lock position without excessive operation by incorporating the elastic means 26 with a greater built-in pressure than the urging force of the release urging means 27 when detecting the pallet. The mounting height and the mounting pressure of the elastic means 26 are controlled by the adjusting nut 28 screwed to the rear end of the shaft 24 to connect the second link arm 22 in the released state in which the driving machine 18 is shortened. Adjustment is made so as to receive the frame 15 and restrain the lock bar 14 to the release position.
[0052]
FIG. 6 is a side view of the pallet lock device when the lock bar 14 is lowered to a lock position where the lock bar 14 contacts the lower deck board 46 of the pallet 40. As shown in FIG. When the lock bar 14, the connection frame 15 and the second link arm 22 are driven by the lower deck board 46 when the lock bar 14 is driven to the lock position where it abuts on the piston rod 19, the bracket of the piston rod 19, the first link arm 21 and the shaft 24. 25, that is, the elastic deformation amount X of the elastic means 26 further increases. For example, when the elastic deformation amount X reaches the upper limit B, the lock bar 14 is pressed against the lower deck board 46 with a predetermined pressure, and Is completed.
[0053]
FIG. 7 is a side view partially showing the excessive operation absorbing mechanism 23. As shown in FIGS. 4 and 7, the rear end of the shaft 24 is provided to prevent the adjustment nut 28 from being loosened. A lock nut 28a is screwed, and a drive piece 29 sandwiched between the adjustment nut 27 and the lock nut 28a drives a deformation amount detection unit 31 of a lock control unit 30 described later.
[0054]
As shown in FIG. 7, the deformation amount detecting means 31 is constituted by, for example, a potentiometer supported on a bracket 25 of the excessive motion absorbing mechanism 23 via a stay 35, and has an arm 37 fixed to an input shaft 36 thereof. The amount of elastic deformation X of the shaft 24 with respect to the bracket 25 of the excessive motion absorbing mechanism 23 is detected by inserting a pin 38 provided at the tip into a U-shaped groove 39 formed in the driving piece 29.
[0055]
By the way, as shown by an imaginary line in FIG. 1, if the fork 6 is lifted after the locking operation is completed in a state where the fork 6 is separated from the upper deck board 41 of the pallet 40 placed on the loading table for some reason, If the lock bar 14 accompanies the fork 6 as it is, a gap is formed between the lock bar 14 and the lower deck board 46 as shown by a virtual line in FIG. Actually, as shown by a solid line in the figure, the lock bar 6 may be urged by the elastic means 26 to a position where it contacts the lower deck board 46, but the elastic deformation amount X of the elastic means 26 is larger than B. In extreme cases, the elastic deformation amount X becomes zero, and a gap may be generated between the lock bar 14 and the lower deck board 46.
[0056]
Then, when the elastic deformation amount X becomes B or more and the driving device 18 is stopped, and the elastic deformation amount X of the elastic means 26 detected by the deformation amount detecting means 31 decreases to less than B. As described later, the control circuit 34 determines that the lock state is incomplete, and starts the reverse operation of the driving machine 18.
[0057]
Although not particularly limited, the rise detecting means 47 is constituted by a microswitch that can be turned on and off by operating a lift lever in a rising direction.
[0058]
As shown in FIGS. 1 and 4, the base plate 11 is provided with a release detecting means 33 composed of, for example, a magnetic switch for detecting that the driving device 18 is shortened and the piston rod 19 is located at the release position. Is supported through.
[0059]
The release detecting means 33 is turned on when the driving device 18 is shortened and the piston rod 19, the first link arm 21 and the shaft 24 are located at the release position, and the first link arm 21 is locked from the release position. When turned in the direction of the position, it is switched off.
[0060]
FIG. 8 is a side view of the pallet lock device 10 in a state where the pallet 40 is placed on a loading table and the fork 6 is separated from the upper deck board 41 by a predetermined distance or more. As shown in FIG. When the fork 6 is placed on the loading table and separated from the upper deck board 41 by a predetermined distance or more, the bracket 25, the second link arm 22, the connection frame 15, and the lock with respect to the piston rod 19, the first link arm 21 and the shaft 24. Since the bar 14 operates excessively, the elastic deformation amount X becomes C or more, which is larger than the upper limit value B.
[0061]
FIG. 9 is a circuit block diagram of the lock control means 30 of the pallet lock device. As shown in FIG. 9, the lock control means 30 includes a deformation amount detection means 31, a pallet detection means 32, a release detection means 33, An elevation detecting means 47 and a control circuit 34 comprising a microprocessor to which the driving means is connected, based on the information provided from these deformation amount detecting means 31, pallet detecting means 32 and release detecting means 33; Activate, reverse activate, or stop 18. Further, the control circuit 34 is connected with an alarm means 47 for alarming the operator of an incompletely locked state based on information provided from the deformation amount detecting means 31.
[0062]
FIG. 10 is a flowchart of a control program executed in the control circuit 34. The control program is repeatedly executed at an appropriate cycle after the main key of the order picking track is turned on until it is turned off.
[0063]
When this control program is started, first, an error check (S1) for checking whether or not each part of the pallet lock device 10 has an error is executed, and it is confirmed that there is no error (S2). Then, the operation mode of the driving machine 18 is set (S3), and the driving machine 18 is controlled according to the setting result (S4).
[0064]
When an error is detected, it is determined whether or not the error is a serious error (S5). If the error is a serious error, the operation and reverse operation of the driving machine 18 are prohibited (S6). Is prohibited (S7), and furthermore, a warning is given to notify the operator that there is an error, for example, by displaying a buzzer, a chime, a warning light, a warning character, or the like (S8).
[0065]
By the way, the operation mode of the driving device 18 is a free mode in which the lock bar 14 is held at the release position, a lock operation mode in which the lock bar 14 is driven from the release position to the lock position, and the lock bar 14 is held at the lock position. There are a lock mode and a release operation mode in which the lock bar 14 returns from the lock position to the release position, and these operation modes are repeated in this order.
[0066]
FIG. 11 is a flow chart of the operation mode setting program (S3), and FIG. 12 is a flow chart of a driving machine control program (S4) following the operation mode setting program (S3). As shown in FIG. In S3), first, it is determined whether or not the release detecting means 33 is on (S31). If it is determined that the release detecting means 33 is on, the pallet detecting means 32 determines whether or not a pallet is detected. (S32).
[0067]
Here, when it is determined that the pallet detecting means 32 is on (pallet non-detection), the operation mode is set to the free mode (S33), and it is determined that the pallet detecting means 32 is off (pallet detection). If so, the operation mode is set to the lock operation mode (S34).
[0068]
When it is determined that the release detecting means 33 is off (S31), it is determined whether the operation mode is the lock operation mode (S35).
[0069]
Here, if it is determined that the operation mode is the lock operation mode (S35), it is determined whether or not the locked state is completed by determining whether or not the elastic deformation amount X ≧ B. (S36).
[0070]
That is, when the operation of the driving device 18 is continued after the lock bar 14 abuts on the lower deck board 46 of the pallet 40, the shaft 24 moves with respect to the lock bar 14, the connection frame 15, the second link arm 22 and the bracket 25. As a result, the first link arm 21 and the piston rod 19 operate excessively, the elastic means 26 is shortened, and the pressure at which the lock bar 14 contacts the lower deck board 46 increases. When the amount of shortening of the elastic means 26, that is, the amount of elastic deformation X becomes, for example, the upper limit value B or more, the state in which the pallet 40 is fixed firmly and firmly to the fork 6, ie, the locked state, is completed. By determining whether or not the lock is completed, it is determined whether or not the lock is completed (S36).
[0071]
In this determination (S36), if the lock is completed, that is, if it is determined that X ≧ B, the operation mode is changed to the lock mode (S37).
[0072]
If it is determined that the operation mode is not the lock operation mode (S35), it is determined whether or not the operation mode is the lock mode (S38). If it is determined that there is, it is determined whether or not the elastic deformation amount X is smaller than B, thereby determining whether or not the incomplete lock state is established (S39).
[0073]
That is, if the pressure (contact pressure) at which the lock bar 14 is brought into contact with the lower deck board 46 of the pallet 40 in the lock mode is set lower than that in the normal lock state, the elastic means 26 is released. When the elastic deformation X is smaller than B, which is the lower limit of the normal lock state, the elastic deformation is restored in response to the pressure drop. it can.
[0074]
Here, when it is determined that the vehicle is in the incompletely locked state, the alarm means 47 is operated to warn the operator of the incompletely locked state (S40), and the operation mode is set to the release operation mode. (S41) If it is determined that the state is not the incompletely locked state, it is determined whether or not the elastic deformation amount X is equal to or more than C, and the loading surface on which the pallet 40 is placed, that is, the rack is detected. It is determined whether or not the operation is performed (S42). If it is determined that the operation is detected, the operation mode is set to the unlock operation (S42).
[0075]
In the rack detection determination (S41), it is determined whether the fork 6 on which the pallet 40 is placed on the loading surface is lowered to a predetermined pallet detection height and the elastic deformation amount X of the elastic means 26 is equal to or more than a predetermined value C. It is determined by whether or not.
[0076]
That is, when the lock bar 14 is pushed back by a predetermined amount from the lock position toward the release position against the elastic means 26 due to the reaction force of the lowering driving force of the fork 6, the elastic means 26 is further shortened, and the elastic deformation X becomes Since it is greater than C which is larger than B, it is determined whether or not the fork 6 has dropped to a rack detection position separated by a predetermined amount or more from the upper deck plate 41 of the pallet 40 placed on the loading table.
[0077]
If it is determined that the operation mode is not the lock mode in the determination of whether the operation mode is the lock mode (S40), the operation mode is set to the release operation mode, and the next drive machine control program Move to (S4).
[0078]
As shown in FIG. 12, in the driving machine control program (S4), the driving machine 18 is controlled according to the operation program set by the operation mode setting program. First, it is determined whether the operation mode is the free mode. (S44) If it is the free mode, it is determined whether or not the driving machine 18 is stopped (S45). If it is stopped, the driving machine control program (S4) ends without doing anything.
[0079]
In the free mode, for example, immediately after the operation mode is switched from the release mode to the free mode, if the driving device 18 is not stopped, the driving device 18 is stopped (S46), and the driving device control program (S4). End.
[0080]
When it is determined that the operation mode is not the free mode (S44), it is determined whether the operation mode is the lock operation mode (S47), and when it is determined that the operation mode is the lock operation mode, Since the amount of elastic deformation X with respect to the bracket 25 is equal to or greater than the upper limit value B, it is determined whether or not the driving device 18 is operating (S48). After the operation of S18 is started (S49), the driving machine control program (S4) ends.
[0081]
If it is determined in the lock operation mode determination (S47) that the current mode is not the lock operation mode, then it is determined whether the current mode is the lock mode (S50). Here, it is determined that the current mode is the lock mode. Then, it is determined whether or not the driving machine 18 is operating (S51). If not, the driving machine control program (S4) ends without performing any operation.
[0082]
Immediately after switching from the lock operation mode to the lock mode, it may be determined that the driving machine 18 is operating. In this case, after the driving machine 18 is stopped (S52), the driving machine control program (S4) is ended.
[0083]
If it is determined in the lock mode determination (S50) that the drive mode is not the lock mode, it is the release operation mode, so it is determined whether or not the driving machine 18 is operating in reverse (S53). If not, the reverse operation of the driving machine 18 is started (S54), and the driving machine control program (S4) ends.
[0084]
If it is detected in the control program repeated from the next time that the release detecting means 33 has been switched on (S31), it is confirmed that no pallet has been detected (S32), and then the operation mode is set to the free mode. (S33), and the reverse operation of the driving device 18 is stopped (S45, S46).
[0085]
As described above, the pallet lock device 10 includes the fork 6 and the lock bar 14 movably provided between a release position that does not hinder the insertion and removal of the fork 6 from the pallet 40 and a lock position that abuts the pallet. Pallet detection means 32 for detecting the inserted pallet, elastic means 26 for setting the contact pressure of the lock bar 14 to the pallet at the lock position, and the lock bar 14 is driven to the lock position via the elastic means 26. A driving unit 18, a deformation detecting unit 31 for detecting an elastic deformation X of the elastic unit 26, and a control circuit 34.
[0086]
When the control circuit 34 of the pallet lock device 10 detects the pallet 40 into which the fork 6 is inserted by the pallet detecting means 32 in a state where the lock bar 14 is located at the release position, the control circuit 34 activates the driving device 18. When the deformation amount detecting means 31 detects that the elastic means 26 is pressing the lock bar 14 against the pallet 40 with a predetermined pressure, the driving means 18 is stopped. Further, thereafter, the incomplete lock state is configured to be detected by detecting a decrease in the amount of deformation of the elastic means 26 by the amount of deformation detection means 31, so that the pallet lock device 10 Such an operation or effect can be obtained.
[0087]
First, in the free mode, it is possible to obtain an effect that the lock control means 30 positions the lock bar 14 at the release position which does not hinder the insertion / removal of the fork 6, so that the operator keeps the lock bar 14 at the lock position. It is possible to obtain the effect of reliably preventing the fork 6 from being mistakenly inserted into the pallet 40. When the pallet 40 carrying the load is picked up from the loading surface, the lock bar 14 may be caught on the pallet 40 and the load may collapse. It can be completely eliminated.
[0088]
Further, in the free mode, when the fork 6 is inserted into the pallet placed on the loading surface and raised to the pallet detection position, the lock control means 30 operates the driving means 16 to move the lock bar 14 to the lock position. The operation of holding the pallet 40 from the loading table while the operator forgets to lock the pallet 40 can be reliably eliminated, and the effect of reliably lifting the pallet 40 from the loading table can be obtained. As the pallet is locked, the pallet can be reliably prevented from tilting, skidding, or swaying, and can be securely prevented from collapsing and the operator from falling down. Can be.
[0089]
Further, according to this pallet lock device, when the pallet 40 locked by the lock bar 14 is placed on the loading table and the fork 6 is further lowered to the rack detection position, the lock control means 30 reversely operates the drive means 16. Then, the lock bar 14 can be moved to the release position and the lock bar 14 can be held at the release position, so that it is possible to reliably eliminate an error that the operator releases the lock before the pallet 40 is placed on the loading table. The effect that it can be obtained can be obtained.
[0090]
Further, the lock bar 14 is driven toward the release position when the fork 6 is removed from the pallet 40 by this action, so that the lock bar 14 does not hinder the fork 6 from being removed. The lock bar 14 can be hooked on the pallet 40, so that the pallet 40 can be surely prevented from being displaced and from being collapsed.
[0091]
In addition, according to the pallet lock device 10, when the pallet 40 is placed on the loading table with the lock bar 14 held at the lock position, and the fork 6 is further lowered to the rack detection position, the lock control means 30 Can operate the driving means 16 in reverse to move the lock bar 14 to the release position and hold it at the release position, so that it is possible to reliably prevent the operator from forgetting to return the lock bar to the release position. The effect described above can be obtained.
[0092]
In addition, according to the pallet lock device 10, the lock bar 14 is separated from the lower deck board 46 of the pallet 40, or the contact pressure on the lower deck board 46 of the lock bar 14 is insufficient, so that the lock bar 14 is in an incomplete lock state. Can be detected, and when the incompletely locked state is detected, the alarm means 47 can alert the operator of the incompletely locked state. it can.
[0093]
In addition, according to the pallet lock device, when it is detected that the lock is incomplete, the lock is automatically released, and the pallet lock device is locked again while the fork 6 is in contact with the upper deck board 41. The operation is re-executed, and the effect that the pallet can be securely locked in the normal lock state can be obtained. Further, with this effect, the operator can confirm the lock state, cancel the incomplete lock, and repeat the lock operation. Therefore, it is possible to obtain an effect that the burden on the operator can be reduced.
[0094]
FIG. 13 is a side view of a pallet lock device 10 of a forklift according to another embodiment of the present invention. The link mechanism 20 of the embodiment shown in FIG. 13 is rotatably supported on a common support shaft 14. The first link arm 21 and the second link arm 22 are wound around the support shaft 14, and one end is locked at an intermediate portion of the first link arm 21, and the other end is locked at the upper end of the second link arm 22. Elastic means 26 formed of a helical spring. The elastic deformation of the elastic means 26 absorbs excessive movement of the second link arm 22, the connection frame 15, and the lock bar 14 with respect to the piston rod 19 and the first link arm 21. I have to.
[0095]
Other configurations, operations and effects of this embodiment are the same as those of the embodiment of the present invention.
[0096]
【The invention's effect】
As described above, according to the present invention, the following operations and effects can be obtained.
[0097]
First, when the pallet into which the fork is inserted is detected by the pallet detection means, the drive means moves the lock bar to the lock position via the elastic means, and holds the lock bar at the lock position with a predetermined contact pressure. Therefore, it is possible to obtain an effect that the mistake of lifting the pallet from the loading table while the operator forgets to lock the pallet can be reliably eliminated.
[0098]
Further, according to the present invention, when the locking operation is completed in a state where the fork is separated from the upper deck board of the pallet, the pressure detecting means detects that the pressure of the elastic means or the amount of elastic deformation decreases when the fork is raised thereafter. Alternatively, the effect of detecting the incomplete lock state in which the contact pressure of the lock bar is lower than a predetermined value can be obtained by detecting the deformation amount using the deformation amount detection means.
[0099]
Further, in the present invention, when an alarm is provided to notify the operator of the incomplete lock state when the incomplete lock state is detected by the control circuit, whether or not the operator is in the incomplete lock state is provided. Can be easily recognized, and the operator can be urged to take an appropriate operation such as, for example, stopping and raising the fork.
[0100]
In addition, in the present invention, the pallet detecting means is configured to detect an upper deck board of the pallet abutting on the upper surface of the fork, and the control circuit reversely operates the driving means when detecting the incompletely locked state. To return the lock bar to the release position.After that, when the pallet detecting means detects that the fork contacts the upper deck board of the pallet, the drive unit is operated to drive the lock bar to the lock position. By using a configuration in which the lock bar is pressed against the pallet with a predetermined pressure by the elastic means, the operator pulls out the fork from the pallet or returns the lock bar to the lock position side without returning the lock bar to the release position. It is possible to obtain the effect of reliably preventing mistakes such as inserting a fork into a pallet while maintaining the pallet. It can be obtained or damage the pallet locking bar collides with bets, the effect that it is possible to prevent or cause collapse of cargo.
[0101]
In addition, this configuration eliminates the need for the operator to confirm the presence or absence of the incomplete lock state and to eliminate the incomplete lock state that has occurred and to perform the lock operation again, so that the burden on the operator is reduced. The effect of being significantly reduced can be obtained.
[0102]
Furthermore, with this configuration, after the incomplete lock is eliminated, the lock operation is performed again in a state where the fork contacts the upper deck board, so that an effect that the normal lock state can be reliably achieved can be obtained. it can.
[Brief description of the drawings]
FIG. 1 is a side view of the present invention.
FIG. 2 is a plan view of the present invention.
FIG. 3 is a side view of an order picking truck to which the present invention is applied.
FIG. 4 is a plan view of the link mechanism of the present invention.
FIG. 5 is a side view when a pallet is detected according to the present invention.
FIG. 6 is a side view in the lock operation mode of the present invention.
FIG. 7 is a side view of the excessive operation absorbing mechanism of the present invention.
FIG. 8 is a side view when a rack is detected according to the present invention.
FIG. 9 is a circuit block diagram of the lock control means of the present invention.
FIG. 10 is a flowchart of a control program according to the present invention.
FIG. 11 is a flowchart of an operation mode setting program of the present invention.
FIG. 12 is a flowchart of a driving machine control program of the present invention.
FIG. 13 is a driving current characteristic diagram of the present invention.
[Explanation of symbols]
6 fork
14 Rock Bar
18 Driving machine
26 elastic means
31 Deformation amount detecting means
32 Pallet detection means
34 control circuit
40 pallets
41 Upper Deck Board
47 Warning means

Claims (3)

A lock bar movably provided between a lock position for locking the pallet and an unlock position for unlocking the pallet, pallet detecting means for detecting the pallet inserted into the fork; An elastic means for setting a contact pressure, a driving device for driving the lock bar to a lock position via the elastic means, a pressure detecting means for detecting a biasing force of the elastic means, or a deformation amount detecting for detecting an elastic deformation amount And a control circuit, and when the control circuit detects the pallet inserted into the fork in a state where the lock bar is located at the release position, the pallet detecting means locks the lock bar by operating the driving device. Position, and after that, the elastic means presses the lock bar against the pallet with a predetermined pressure, and the pressure detecting means or When the deformation is detected by the deformation detecting means, the driving machine is stopped, and thereafter, while the rise of the fork is detected by the rising detecting means, the pressure of the elastic means is decreased by the pressure detecting means or the elastic means is detected by the deformation detecting means. A pallet lock device for a forklift, wherein an incomplete lock state is detected by detecting a decrease in the amount of deformation of the pallet. 2. The pallet lock device for a forklift according to claim 1, further comprising an alarm unit for notifying an operator of the incomplete lock state when the control circuit detects the incomplete lock state. The pallet detecting means is configured to detect an upper deck board of a pallet abutting on an upper surface of a fork, and when the control circuit detects an incompletely locked state, the drive unit is reversely operated to release a lock bar at a release position. After that, when the pallet detecting means detects that the fork is in contact with the upper deck board of the pallet, the driving device is operated to drive the lock bar to the lock position, and the lock is locked by the elastic means. The pallet lock device for a forklift according to claim 1, wherein the bar is pressed against the pallet with a predetermined pressure.

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