JP4232954B2 - Forklift pallet locking device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pallet locking device for a forklift, and more particularly to a pallet locking device for a forklift in which a cab that moves up and down together with a fork is provided with an open / close guard for preventing falling.
[0002]
[Prior art]
An order picking truck, which is a kind of forklift, includes a fork for insertion into a pallet and a cab that moves up and down with the fork, and a floor on which an operator stands on the cab. The operator moves up and down with the pallet inserted into the fork, and performs a picking operation of the load between the shelf and the pallet.
[0003]
The operator does the picking work on the above floor, but sometimes this is done on the pallet, and if the pallet swings on the fork at this time, it is difficult to operate and there is a risk that the operator will fall, so this is prevented A pallet locking device for this purpose has been proposed by the following patent document.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-228085 [Patent Document 2]
JP 2001-316095 A [Patent Document 3]
Japanese Patent Laid-Open No. 2002-12397 [Patent Document 4]
Japanese Patent Laid-Open No. 10-291790 [Patent Document 5]
Japanese Patent Laid-Open No. 10-316380
[Problems to be solved by the invention]
Any of those described in these patent documents manually locks the pallet, and therefore it is impossible to avoid the danger caused by forgetting the lock. Even if the lock is automatically performed, the risk of performing the picking operation without the lock being performed cannot be completely avoided unless the lock timing is appropriately set.
[0006]
The invention described in the above-mentioned Patent Document 5 is obtained by adding certain considerations to such a situation. That is, according to the present invention, a guard for preventing the operator from dropping is provided, and when the guard is in a horizontal state, the pallet is locked in conjunction with the operation. Therefore, according to the invention of Patent Document 5, the pallet can be reliably locked on the assumption that the operator always performs the turning operation of the guard.
[0007]
However, the invention of Patent Document 5 is not intended for the above-described order picking truck, that is, it does not have a floor for the operator to board, and the operator has boarded directly on the pallet inserted in the fork. The lift and picking operations are performed by
[0008]
Therefore, the invention of Patent Document 5 is not an order picking truck type forklift that is the subject of the present invention. Therefore, there is no distinction between a floor and a pallet, and an operator moves between the floor and the pallet. It is not assumed. If the invention of Patent Document 5 is applied to an order picking truck, if the operator raises the guard to move onto the pallet from the floor, the pallet is unlocked immediately.
[0009]
The present invention is not affected by the swing of the pallet when the operator is on the floor (regardless of whether the guard is opened or closed). It focuses on the circumstances peculiar to the order picking truck that it is necessary to prevent the movement. The present invention has been accomplished under such a background, and an object thereof is to provide a safe pallet locking device suitable for an order picking truck type forklift.
[0010]
[Means for solving the problems]
In order to achieve this object, the present invention comprises a fork for insertion into a pallet and a cab that moves up and down with the fork, and a floor on which the operator gets on the cab and an opening / closing that surrounds the operator on the floor In a forklift having a possible guard, a lock bar that presses and locks the pallet inserted into the fork, an opening detection means that detects the opening of the guard, a drive means that operates the lock bar, and the drive A control means for controlling the means and a pallet detection means for detecting the pallet on the fork, wherein the pallet is detected by the pallet detection means, and the guard is opened by the opening detection means. When detected, the control means controls the drive means to operate the lock bar to lower the pallet. Providing pallet locking device of a forklift, characterized in that to click.
[0011]
According to the present invention, when an operator performs an operation on a pallet, the pallet can be reliably prevented from swinging. Therefore, the present invention is extremely useful in preventing an accident such as dropping from the pallet. The pallet locking device of the present invention can be applied to either a manual type or an automatic type, and includes both.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
A pallet locking device for a forklift according to an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, FIG. 1 is a functional block diagram of a pallet locking device for a forklift according to an embodiment of the present invention, FIG. 2 is a flowchart of its control program, and FIG. 3 shows an order picking truck equipped with the pallet locking device. It is a perspective view.
[0013]
As shown in FIG. 3, the forklift 1 is called an order picking truck, and is supported at the rear ends of the left and right straddle legs 3 projecting rearward of the vehicle body 2 so as to be rotatable around the left and right axis. The vehicle is caused to travel by the road wheel 4 and a drive wheel supported by the vehicle body 2 via a travel motor housed therein.
[0014]
A mast 5 is erected on the rear side of the vehicle body 2, and a cab 6 is supported on the mast 5 so as to be movable up and down, and left and right forks 7 are fixed below the floor 6 a of the cab 6.
[0015]
The driver's cab 6 is provided with an openable / closable guard 8 that prevents an operator who is standing on the floor 6a from operating the forklift from falling. The guard 8 includes pipe members bent in a U-shape along the left and right side edges and the rear edge of the floor 6a in plan view, and the left and right front ends of the pipe material serve as left and right corner posts of the cab 6. 6b, a closed position in which the rear edge of the pipe member is located at the driver's waist level as shown in FIG. 3, for example, as shown in FIG. 3, and the rear edge of the pipe member is near the head guard 6c. It is supported so as to be able to rotate between the open position where it can be flipped up. Further, positioning means (or locking means) is provided so that positioning can be performed between the open position and the closed position.
[0016]
The forklift 1 is provided with an arm-type auxiliary guard 9 in order to prevent the operator from falling from the floor 6a to the left and right sides when the guard 8 is opened.
[0017]
4 is a plan view of the pallet locking device 10 provided in the forklift 1, and FIG. 5 is a side view of the pallet locking device in a free state (unlocked state). FIG. 4 and FIG. As shown, the pallet locking device 10 is supported by a base plate 11 fixed to a lower portion of the front panel 6d of the cab 6 and a lower surface of the floor 6a, and a rear end portion of the base plate 11 via left and right brackets 12. A support shaft 13, a left and right lock bar 14 that is supported on the support shaft 13 so as to be rotatable about its axis, that is, around the left and right axis, and a connecting frame 15 that connects the intermediate portions thereof. Is provided.
[0018]
As shown in FIG. 4, the left and right lock bars 14 are disposed inside the left and right forks 7 and extend rearward from the rear edge of the floor 6a. Further, each lock bar 14 is formed in a bowl shape in which the tip portion protrudes above the upper surface of the fork 7 in a free state.
[0019]
The pallet locking device 10 includes driving means 16 for driving the left and right lock bars 14 in the locking operation direction, and the driving means 16 is pivotally supported by the base plate 11 via a shaft 17. An actuator 18 composed of an electric cylinder and an output portion of the actuator 18, that is, a link mechanism 20 connected to a piston rod 19 are provided.
[0020]
The link mechanism 20 has a lower end supported by the base plate 11 so as to be rotatable around a left and right axis, a first link arm 21 having an upper end connected to the piston rod 19, and a lower end connected to the base plate 11. A second link arm 22 that is supported so as to be rotatable about an axis center, and an intermediate portion or an upper end portion receives the connection frame 15 from the front, and an intermediate portion of the first link arm 21 is an upper end portion of the second link arm 22. And an excessive motion absorbing mechanism 23 to be connected.
[0021]
The excessive motion absorbing mechanism 23 includes a shaft 24 whose front end is connected to an intermediate portion of the first link arm 21 so as to be rotatable around a left and right axis, and a rear end of the shaft 24 is movable in the axial direction. And a bracket 25 that is connected to the upper end of the second link arm 22 so as to be rotatable about the left and right axis, and for example, a compression coil spring that urges the bracket 25 toward the rear end of the shaft 24. And an excessive operation of the shaft 24 with respect to the bracket 25 is absorbed.
[0022]
On the other hand, the lock bar 14 is urged in a direction (release direction) in which the connection frame 15 is pressed against the second link arm 22 by release urging means 27 that is stretched over the connection frame 15 and the base plate 11. Yes.
[0023]
A pallet detection sensor 32 made of, for example, a magnetic sensor is supported on the base plate 11 via a bracket 42 so as to be positioned on the left side of the first link arm 21, and a driving piece for driving the pallet detection sensor 32 is connected to the connection frame 15. 43 is supported via an arm 44. The drive piece 43 approaches the pallet detection sensor 32 in the free state, and the pallet detection sensor 32 provides, for example, an ON signal to the control means 35 shown in FIG.
[0024]
6 is a side view of the pallet locking device 10 in a pallet detection state. As shown in FIG. 6, when the fork 7 inserted into the pallet 40 receives the upper deck board 41 of the pallet 40, the lock bar 14 is used. 1 is positioned at a pallet detection position where the tip portion sinks to the height of the upper surface of the fork 7, the drive piece 43 is separated from the pallet sensor 32, and a pallet detection signal comprising, for example, an off signal is sent to the control means 35 shown in FIG. give.
[0025]
FIG. 7 is a side view of the pallet locking device 10 in the locked state. As shown in FIG. 7, in the locked state, the actuator 18 extends and the lock urging means 26 pushes the lock bar 14 under the pallet 40. Press against the deck board 46.
[0026]
FIG. 8 is a side view of the pallet locking device 10 in the landing detection state. After the pallet 40 is grounded in the locked state, when the fork 7 is further lowered as shown in FIG. Since it is pushed up by the lower deck board 46 of the pallet 40, the lock urging means 26 is compressed more than in the locked state.
[0027]
FIG. 9 is an enlarged side view showing a portion indicated by an arrow A in FIG. 5. As shown in FIG. 9, a landing detection sensor 31 including a potentiometer is supported on the bracket 25 via a stay 35. A pin 38 is connected to the input shaft 36 of the landing sensor 31 via an arm 37. The pin 38 is inserted into the pin groove 39 of the drive piece 29 fixed to the rear end portion of the shaft 24, thereby driving the input shaft 36 of the landing sensor 31 by the drive piece 29.
[0028]
In the locked state, the pin 38 and the pin groove 39 are located from the position indicated by B in FIG. 9 to the position indicated by C. However, in the landing detection state where the lock urging means 26 is shortened compared to the locked state, the pin 38 38 and the pin groove 39 are located on the right side of the position indicated by C, and the landing detection sensor 31 gives a landing detection signal having a signal value corresponding to the landing detection position on the right side of the C to the control means 35.
[0029]
As shown in FIG. 3, the instrument panel 6e of the cab 6 is provided with a lock switch so that the operator can freely lock and unlock the pallet when the guard 8 is closed. 33 is provided, and for example, an open detection means 34 for detecting that the guard 8 is in the open position is provided on one of the left and right corner posts 6b.
[0030]
The lock switch 33 is not particularly limited. For example, the lock switch 33 is configured as a sea source switch, and the open detection unit 34 is configured as a micro switch, for example.
[0031]
As shown in FIG. 1, the control means 35 controls the actuator 18 according to the control program shown in FIG. 2 based on the signals given from the pallet detection means 32, the landing detection means 31 and the lock switch 33.
[0032]
That is, when the control program is started, first, it is determined whether or not the pallet 40 is inserted by determining whether or not a detection signal is given from the pallet detection means 32 (S1). If it is determined (YES), whether or not the pallet has landed is determined by determining whether or not a landing detection signal is given from the landing detection means 31 (S2). .
[0033]
If it is determined that the pallet has not landed (YES), it is determined whether or not the guard 8 is detected by determining whether or not the detection signal given when the opening detection means 34 detects the opening. It is determined whether or not it is opened (S3).
[0034]
Here, when it is determined that the guard 8 is opened (YES), it is determined whether or not it is currently locked (S4), and when it is determined that it is currently locked (YES), it is left as it is. If not (NO), the control program is terminated after a pallet locking operation (S5) for extending the actuator 18 is performed.
[0035]
In short, when the pallet 40 is supported on the fork 7 (YES in S1) and lifted from the ground (YES in S2), when the guard 8 is opened (YES in S3), regardless of the operator's intention, If the pallet 40 is actually locked, this locked state is maintained. If the pallet 40 is not actually locked, the lock operation is immediately started and the locked state is established. When changing to, it is surely locked, so that the user can never forget the lock operation and can keep safe.
[0036]
Further, according to the pallet locking device 10, when the operator changes to the pallet 40, the pallet is automatically locked, so that it is not necessary to warn the operator that the guard 8 has been opened in the unlocked state. There is no need to provide expensive alarm means such as a voice alarm device that allows the operator to recognize the meaning of the alarm, or alarm means that emits an alarm different from the alarm used for other alarms, and the effect of reducing the burden on the operator, etc. Can be obtained.
[0037]
In this embodiment, as shown in FIG. 2, when it is determined that the pallet is not inserted (NO) in the step (S1) of determining whether or not the pallet is inserted, the lock bar 14 is After that, it is determined whether or not it is currently in a free state so as not to prevent insertion of a pallet (S7). If it is determined that it is in a free state (YES), it is determined that it is not (NO) as it is. Completes the control program 6 after releasing the pallet lock (S8) to shorten the actuator 18.
[0038]
Further, when determining whether or not the guard 8 is opened, if it is determined that the guard 8 is not opened (NO in S3), it is determined whether or not the lock switch 33 that the operator arbitrarily switches is on. (S6) If it is determined to be on (YES), the actuator 18 is controlled to be in the locked state, and if it is determined to be off (NO), the lock is released, that is, the free state is set. The actuator 18 is controlled.
[0039]
【The invention's effect】
As described above, according to the first aspect of the present invention, when an operator changes to a pallet, the pallet can be reliably locked, so that forgetting to lock is prevented and a safe picking operation can be realized.
[0040]
Further , according to the invention of claim 1 , since the pallet locking device is automated, there is an effect that the operation becomes more reliable.
[0041]
According to the invention of claim 2 , when there is a special circumstance, the pallet can be locked or unlocked freely at the will of the operator, so that there is an effect that a flexible work according to various circumstances can be realized. .
[Brief description of the drawings]
FIG. 1 is a functional block diagram of the present invention.
FIG. 2 is a flowchart of a control program of the present invention.
FIG. 3 is a perspective view of a forklift to which the present invention is applied.
FIG. 4 is a plan view of the present invention.
FIG. 5 is a side view of the present invention in a free state.
FIG. 6 is a side view of the present invention in a pallet detection state.
FIG. 7 is a side view of the present invention in a locked state.
FIG. 8 is a side view of the present invention in a landing detection state.
FIG. 9 is an enlarged side view of the present invention showing a portion indicated by an arrow A in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Forklift 6 Driver's cab 7 Fork 8 Guard 14 Lock bar 18 Actuator 31 Landing detection means 32 Pallet detection means 33 Lock switch 34 Opening detection means 35 Control means 40 Pallet

Claims (2)

A forklift comprising a fork for insertion into a pallet and a cab that moves up and down together with the fork, and a floor for an operator to board the cab and an openable / closable guard surrounding the operator on the floor. A lock bar that presses and locks the pallet inserted in the pallet, an open detection means that detects the opening of the guard, a drive means that operates the lock bar, a control means that controls the drive means, and a fork on the fork Pallet detection means for detecting the pallet, and when the pallet detection means detects the pallet and the opening detection means detects that the guard is opened, the control means detects the pallet. fork, characterized in that for locking the pallet by operating the locking bar controls the means Shift of the pallet locking device. The pallet locking device for a forklift according to claim 1 , wherein a switch for instructing a driver to lock or unlock the lock bar is provided in the control means.

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