JP4817223B2 - forklift - Google Patents

Description

The present invention relates to a forklift, and more particularly, to a forklift provided with a pallet locking device that fixes a pallet inserted into the fork so as not to be displaced and swing.

The pallet lock device has been developed mainly for preventing an operator from dropping accidents due to swinging of a pallet in an order picking forklift in which an operator gets on the pallet to perform a picking operation. There are a manual type and an automatic type of this locking device. However, since the manual type may forget the lock operation and the release operation, the adoption of the automatic type is increasing. Patent Document 1 and Patent Document 2 below describe examples of order picking forklifts that employ such an automatic pallet locking device.
JP 2003-252595 A JP 2003-40594 A

By the way, the pallet lock device is extremely useful as a device for ensuring the safety of the operator as described above. However, since the pallet lock device can prevent load collapse due to unexpected sliding of the pallet, it can be applied to forklifts other than the order picking type. Expected.
However, the timing for operating the pallet lock differs greatly between order picking forklifts and non-order picking forklifts.
Specifically, the order picking forklift requires a pallet lock operation when picking work, that is, when the vehicle is stopped and the pallet is at a high height, whereas forklifts other than the order picking type, for example, reach type The counter balance type forklift needs to operate the pallet lock when carrying the load, that is, when the vehicle is running and the pallet is located at a low height.
Further, in the invention of the above-mentioned Patent Document 1, it is configured to detect that the pallet is placed on the shelf or the ground and automatically perform unlocking, but this detection is not normally performed. The release could be incomplete. Therefore, when the pallet is placed on a shelf in a high place and the fork is pulled out, the release of the pallet lock is incomplete and the pallet is pulled out by being hooked on the fork or locking device, dropping the load from the high place. There was a risk of it.
The invention of the above-mentioned Patent Document 2 is such that the pallet is automatically locked when the lifting platform that cooperates with the pallet reaches the reference height, and the lock is automatically released when the lifting platform reaches the descending end. is there.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a forklift that can safely work without dropping a load when unloading to a high place. .

Forklift according to the present invention in order to solve the above problems, a mast erected on the right and left vehicle front, a lift bracket raised and lowered along said mast, a fork which is supported by the lift bracket, the fork And a pallet locking device for locking the pallet into which the fork is inserted to the fork, and detecting that the fork has reached the second region above the predetermined lifting height from the first region below the predetermined lifting height. A lift detecting device, and when the fork is lifted up in the first region, the pallet locking device locks the pallet, and the fork is lifted up from the first region to the second region. when it reaches the area, depending on the output of the fork height detector, the pallet locking device is characterized in that releasing the pallet automatically

Further, in the above configuration, the pallet lock device includes a lock bar inserted into the pallet together with the fork, a lock drive device for turning the lock bar to a lock position for locking the pallet, and the lock drive device. and a control unit for controlling, the control device, depending on the output of the fork height detector, it is preferable to release the driving of the lock driving device.

Further, in the above configuration, the lift detection device is configured by a limit switch, and the limit switch is attached to the mast at a position of the predetermined lift, and the lift bracket is provided for the limit switch. A dog is preferably attached.
However, the mast here means a mast that is supported by a vehicle body or the like and does not slide up and down.

Further, in the above configuration, means for notifying an operator of a locked state and a released state of the pallet lock device may be provided.

According to the forklift of the present invention configured as described above, the forklift includes a lift detection device that detects that the fork has reached a predetermined lift, and when the fork reaches a predetermined lift or higher, the lift detection is performed. Since the pallet lock is automatically released according to the output of the device, it is possible to work safely without dropping the load from a high place.
When means for notifying the operator of the locked state and the released state of the pallet locking device is provided, the cargo handling operation at a high place can be performed more safely.

Hereinafter, a forklift according to the present invention will be described in detail with reference to the accompanying drawings.

First, a forklift that is not equipped with a pallet lock device and a lift detection device will be described. FIG. 1 is a perspective view showing the forklift 1.

As shown in FIG. 1, the forklift 1 includes a vehicle body 29 provided with a head guard 28 on the upper side, two masts 2 each including an outer mast 2a and an inner mast 2b that are erected on the left and right sides of the front of the vehicle body. And a lift bracket 3 supported by the inner mast 2b so as to be movable up and down. The outer mast 2a is supported by a pair of straddle legs 4 projecting forward (indicated by an arrow X) of the forklift 1 so as to be movable back and forth, and the inner mast 2b is attached to the inner side of the outer mast 2a so as to be vertically slidable. Yes. A pair of left and right lift cylinders 5 are provided upright along the mast 2. The fork 6 has an L-shape in a side view made up of a vertical portion 6a and a horizontal portion 6b, and is suspended from an upper end 6c of the vertical portion 6a so as to be slidable on the tilt shaft 7 described below.

The lift bracket 3 includes a tilt shaft 7 provided horizontally in the left-right direction of the vehicle body, that is, in the vehicle width direction (indicated by an arrow W), a tilt cylinder 8 fixed below the tilt shaft 7, and an upper end rotating around the tilt shaft 7. And a tilt bar 9 supported movably. When the lift cylinder 5 is extended, the lift bracket 3 is lifted while being guided by the two inner masts 2b on both sides, and when the lift cylinder 5 is shortened, the lift bracket 3 is lowered.

Next, the pallet lock device 10 when not controlled using the lift detection device will be described. 2 is a front view of the pallet locking device 10, FIG. 3 is a front view showing a state where the pallet locking device 10 is attached to the tilt bar 9, and FIG. 4 is a side view thereof. FIG. 5 is a schematic diagram for explaining the operation of the lock bar.

2 to 4, the pallet locking device 10 has a lock driving device 12 having an operating rod 11 that moves forward and backward in the vertical direction (indicated by an arrow Y), and two forks 6 in the hole of the pallet P. A pair of lock bars 13 that can enter and a support means 14 that supports the lock bars 13 so as to be able to follow the operating rods 11 of the lock driving device 12 are provided.

As shown in FIGS. 3 and 4, the tilt bar 9 includes a pair of bearing portions 9 a rotatably connected to the tilt shaft 7 and a pair extending downward from the bearing portions 9 a and spaced apart from each other in the vehicle width direction. 1 and the lower ends of the hanging arms 9b are connected to each other, arranged behind the respective vertical portions 6a of the two forks 6 shown in FIG. There is provided a horizontal member 9c that comes into contact with, and a hanging piece 9d that hangs down from the horizontal member 9c and holds a locking support shaft 21 described later in parallel with the tilt shaft 7.

When the operating rod (not shown) of the tilt cylinder 8 moves forward and backward based on the lever operation of the operator, the two forks 6 move in the direction in which the horizontal portions 6b move up and down together with the horizontal member 9c of the tilt bar 9. (Tilted) (indicated by arrow Z) with the tilt shaft 7 as a fulcrum.

The lock drive device 12 is mainly composed of a lock cylinder 12a whose upper end is rotatably supported on the tilt shaft 7 via a bracket 15 and a pin 16, and an electric motor coupled to a side near the upper end of the lock cylinder 12a. And a locking drive source 12b. As the lock cylinder 12a is driven, the operating rod 11 in the lock cylinder 12a moves back and forth in the vertical direction. The actuating rod 11 rotatably connects a U-shaped block 18 via a pin 17.

On the other hand, the support means 14 includes a swing link 20 connected to the U-shaped block 18 via a shock absorber 19, and a swing support 20 that is pivotally supported by the lock support shaft 21, and a base end 20 a and a distal end 20 b of the swing link 20. And a biasing means 23 for pulling up the support 22 so as to be close to the swing link 20. The swing link 20 has a side surface curved in a substantially square shape, and its base end 20a is rotatably supported by the lock support shaft 21, and extends from the base end 20a to the front of the lock support shaft 21. The tip 20b to be pin-connected to the shock absorber 19 is pinned. The biasing means 23 is a return spring having an upper end connected to a proper position of the tilt bar 9 and a lower end connected to the support 22.

As shown in FIGS. 3 and 4, the lock cylinder 12 a of the lock driving device 12 is disposed upright at the center position in the vehicle width direction with respect to the lift bracket 3, that is, at the vehicle body front position of the lift cylinder 5. .

When the lock cylinder 12a is driven, the operating rod 11 advances downward, and the swing link 20 rotates about the lock support shaft 21 clockwise in FIG. At this time, the lock cylinder 12a rotates around the pin 16, and the lower end side of the lock cylinder 12a moves slightly forward of the vehicle body to suppress the support 22 from above. As a result, the fork side tip of the lock bar 13 pivots downward about the lock spindle 21. When the drive of the lock cylinder 12a is released and is not driven, the operating rod 11 is retracted upward, and the swing link 20 is rotated to the original position. Then, the support body 22 is released from the suppression from the lock cylinder 12 a and is pulled upward by the force of the spring 23. As a result, the fork side tip of the lock bar 13 pivots upward about the lock spindle 21 and returns to the normal horizontal state.

In FIG. 5, the base end portion of the lock bar 13 extends rearward and a magnet 24 is fixed to the tip thereof, and a magnetic sensor 25 for detecting the magnet 24 is fixed to the lift bracket 3 side. . As shown in FIG. 5 a, when the fork 6 is inserted into the hole of the pallet P, the lock bar 13 is also inserted simultaneously with the fork 6. At this time, the sensor 25 detects a predetermined amount of magnetism from the magnet 24, and outputs an OFF signal to the lock drive source 12b via a control device (not shown). By this OFF signal, the lock driving source 12b, that is, the lock cylinder 12a is controlled to be in a non-driven state, and the lock bar 13 is maintained in a horizontal state (unlocked state) by the force of the spring 23.

Next, as shown in FIG. 5 b, when the fork 6 is lifted up, the slanted protrusion formed on the upper portion of the lock bar 13 comes into contact with the upper deck board P <b> 2 of the pallet P from below before the fork 6. The lock bar 13 turns so that the tip thereof is directed downward. At this time, the sensor 25 cannot detect the predetermined amount of magnetism from the magnet 24, and outputs an ON signal to the lock drive source 12b via a control device (not shown). By this ON signal, the lock driving source 12b, that is, the lock cylinder 12a is driven, and the lock bar 13 starts to turn more positively as described above.

Next, as shown in FIG. 5c, in order to lock the pallet, the lock bar 13 is brought into contact with the lower deck board P1 of the pallet P from above so that the pallet P cannot swing relative to the fork 6. Keep fixed so that it cannot slide.

If the fork 6 is lifted down and the pallet P is placed on the ground from the state of FIG. 5c, and the fork 6 is further lifted down to be pulled out of the pallet P, the lock bar 13 is moved to the lower deck board P1. It turns upward in response to upward reaction force. At this time, the sensor 25 detects a predetermined amount of magnetism from the magnet 24, outputs an OFF signal, and controls the lock cylinder 12a to a non-driven state. As a result, the lock bar 13 is returned to and maintained in the original horizontal state (unlocked state) by the force of the spring 23.

Next, the lift detection device will be described. FIG. 6 is a side view schematically showing the configuration of the lift detection device 26 according to the present embodiment. As shown in FIG. 6, the lift detection device 26 includes a limit switch 26a provided on one outer mast 2a and a dog 26b provided on the lift bracket 3 so as to face the limit switch 26a. Here, the limit switch 26a is disposed at a height that is about a half of the height from the ground to the upper end of the outer mast 2a, and the dog 26b that cooperates with the lift bracket 3, that is, the fork 6, is higher than this position. When it is in the position (FIG. 6a), it outputs an OFF signal to a control device (not shown), and when it is at a position lower than this position (FIG. 6b), it outputs an ON signal.

Next, a method for controlling the pallet locking device 10 using the lift height detecting means 26 will be described. FIG. 7 is a control block diagram of the pallet lock device 10. As shown in FIG. 7, a signal from the magnetic sensor 25 in the pallet device 10 and a signal from the limit switch 26 a in the lift detection device 26 are input to the control device 27. When the signal from the limit switch 26a is an ON signal, the control device 27 controls the lock driving source 12b by the signal from the magnetic sensor 25, and controls the pallet P to the locked state or the unlocked state as described above. To do. On the other hand, when the signal from the limit switch 26a is an OFF signal, the control device 27 controls the pallet P to the unlocked state regardless of the signal from the magnetic sensor 25.

As described above, if the dog 26b, that is, the fork 6 is at a position higher than the mounting position of the limit switch 26a, the pallet P is always in an unlocked state because there is a high possibility of a personal injury due to the fall of the load. When placing on a shelf or the like in a high place, there is no danger of the pallet being caught by a fork or a lock device and dropping the load, and the cargo handling operation can be performed safely.

As mentioned above, although embodiment of this invention was described, demonstrating a specific example, this invention is not limited to these specific examples. An indicator or a notification device for notifying the lock state and the release state of the pallet lock device may be further provided in the driver seat. In this case, the cargo handling operation can be performed more safely.
The dog or limit switch may be attached to the lift bracket or outer mast so as to be movable in the vertical direction. In this case, the predetermined lifting height at which the pallet locking device is unlocked can be appropriately selected according to the cargo handling operation. Further, a non-contact sensor such as a magnetic sensor may be used instead of the limit switch.
The forklift according to the above embodiment is a reach-type forklift, but may be a counterbalance forklift having a counterweight at the rear of the vehicle body.

It is a perspective view of a forklift concerning an embodiment of the present invention. It is a front view of the pallet lock device applied to the forklift concerning the embodiment of the present invention. It is a front view which shows the example of attachment of the pallet locking device applied to the forklift concerning the embodiment of the present invention. It is a side view showing an example of attachment of a pallet locking device applied to a forklift according to an embodiment of the present invention. It is a schematic diagram for demonstrating the effect | action of the lock bar of the pallet lock apparatus concerning embodiment of this invention. It is a schematic side view which shows the structure of the lifting height detection apparatus concerning embodiment of this invention. It is a control block diagram of the pallet lock device concerning the embodiment of the present invention.

Explanation of symbols

P Pallet 3 Lift bracket 6 Fork 10 Pallet lock device

Claims (4)

Mast (2) erected on right and left vehicle front, a lift bracket (3) which is moved up and down along the mast (2), a fork (6) of the supported by the lift bracket (3), the fork (6) and is inserted pallets locking device for locking the (P) the fork (6) (10), said fork (6) of a predetermined lift height first lower than (S) A lift detection device (26) for detecting that the second region (R) not less than the predetermined lift (S ) has been reached from the region (Q) ,
When the fork (6) is lifted up in the first region (Q), the pallet locking device (10) locks the pallet (P),
When the fork (6) has reached the second region from the lifts up the first region (Q) (R), the depending on the output of the fork height detector (26), the pallet locking device (10) A forklift that automatically releases the pallet (P) . The pallet lock device (10) pivots the lock bar (13) to a lock position for locking the pallet (P) and a lock bar (13) inserted into the pallet (P) together with the fork (6). a locking drive for (12), the lock driving device comprises a control device and (27) for controlling (12), said controller (27), the said fork height detector (26) Therefore the output, the forklift according to claim 1, characterized in that to release the driving of the lock driving device (12). The fork height detector (26) is constituted by a limit switch (26a), together with the limit switch (26a) is attached to a position of the predetermined lifting height (S) in the mast (2), wherein The forklift according to claim 1 or 2 , wherein a dog (26b) for the limit switch (26a) is attached to a lift bracket (3) . The forklift according to any one of claims 1 to 3 , further comprising means for notifying an operator of a locked state and a released state of the pallet locking device (10) .

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