JP2003182995A - Pallet lock device for forklift truck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lock a pallet lifted with forks against accidental displacement upon an impact in transfer. <P>SOLUTION: A forklift truck has masts 2 and 5 raised on a vehicle body 1, lift brackets 6 vertically movable along the masts 2 and 5, and the forks 10 supported on the lift brackets 6. The lift brackets 6 are provided with a locking means R operated electrically or hydraulically to lock a pallet P in which the forks 10 are inserted. The locking means R comprises drive mechanisms 12, and lock bars 13 lowered by the drive mechanisms 12 to abut a lower deck board P2 of the pallet P. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pallet lock device for a forklift, which locks a pallet lifted by a fork so that the pallet will not be accidentally displaced during transportation.

[0002]

2. Description of the Related Art Conventionally, an example of a reach type forklift truck is shown in FIG. This has a vehicle body 1 provided with drive tires 1a and caster tires 1b, and a pair of left and right straddle legs 1A with road wheels 1c protruding forward from the lower end of the front surface of the vehicle body 1. By engaging the wheel 3 provided at the lower end with the guide groove 4 formed on the inner surface of each straddle leg 1A, each outer mast 2 is formed so as to be movable in the front-rear direction a, b, and each outer mast 2 is formed. The lift brackets 6 are arranged so as to be able to move up and down on the pair of left and right inner masts 5 which are engaged so as to be able to move up and down.
5, a lift bracket 6 rotatably supports a rotating frame 9 via a support shaft 8, and a pair of left and right forks 10 arranged on the front surface of the rotating frame 9 supports the support shaft. A tilting device 11 composed of a hydraulic cylinder that is rotatably supported by 8 and that tilts both forks 10 in the vertical directions c and d via a tilt bar 9a that is installed on a rotating frame 9.
Are provided on the lift bracket 6.

In the above structure, when carrying out a cargo handling operation, the forks 10 in the horizontal state are advanced by advancing the masts 2, 5 with the forks 10 lowered (see the chain double-dashed line in FIG. 18). The tip of the pallet P has a hole Pa
(See the alternate long and short dash line in FIG. 18) and lifts the fork 10 to lift the load W through the pallet P. Then, the tilt device 11 is driven to drive the fork 10
Is tilted upward c, the load W is tilted toward the backrest 9b side of the rotating frame 9, and the vehicle body 1 is run, whereby the load W is transported to a predetermined position.

[0004]

In the above-mentioned conventional configuration, when the load W is lifted and conveyed by the fork 10 via the pallet P, the conveyance work is performed in a place such as a freezer where dew condensation is likely to occur on the pallet P. For example, when using a synthetic resin pallet P with a small friction coefficient,
The pallet P may slip on the fork 10 and be displaced, causing a load collapse.

In view of the above-mentioned drawbacks of the prior art, it is an object of the present invention to provide a pallet lock device for a forklift that locks a pallet lifted by a fork so as not to be accidentally displaced.

[0006]

In order to achieve the above-mentioned object, as a first invention, a mast erected on a vehicle body, a lift bracket which is raised and lowered along the mast, and a lift bracket supported by the lift bracket are provided. In a forklift having a fork, there is provided a pallet lock device for a forklift, characterized in that lock means for locking a pallet inserted into the fork operated by electricity or hydraulic pressure is provided on the lift bracket.

According to the first aspect of the present invention, since the lock means for locking the pallet inserted into the fork is provided on the lift bracket, the lock means can be provided at an appropriate position near the fork. Since the lift bracket always moves up and down along with the fork along with the fork, the relative positional relationship between the locking means and the fork does not change, so that a pallet locking device capable of reliably locking the pallet is realized. be able to. Since the locking means is not operated by a manual operation of an operator such as a lever operation or a pedal operation, it is operated by electricity or hydraulic pressure, so that it is installed on a lift bracket far from the driver's seat. Also, it became possible to operate it reliably.

As a second invention, in the first invention, the lock means comprises a lock bar for pressing a pallet inserted in the fork and a drive mechanism for operating the lock bar. A pallet lock device for a forklift is provided in which a mechanism is disposed below the lift bracket.

According to the second aspect of the invention, since the drive mechanism for actuating the lock bar is arranged below the lift bracket, the position of the drive mechanism approaches the fork and is therefore inserted into the fork. The mechanical connection between the lock bar that presses the pallet and the drive mechanism can be easily configured. The lock bar may be single or plural,
It may be rod-shaped or hook-shaped. The rod shape is convenient for pressure contact with the pallet, and the hook shape is convenient for engaging with the irregularities or holes of the pallet. The drive mechanism means a motor, a solenoid, a cylinder and its attached devices which are mechanically operated by electricity or hydraulic pressure, and does not mean a lever manually operated by an operator or a wire connected thereto. . In the second aspect of the invention, the drive mechanism being disposed below the lift bracket means that the drive mechanism is not disposed at the upper portion or the center of the lift bracket, but is disposed at a position closer to the lower side thereof. Therefore, it is also included that the lift bracket is disposed below the lower end of the lift bracket.

As a third invention, there is provided a pallet lock device for a forklift truck according to the second invention, wherein the drive mechanism includes a hydraulic or electric cylinder device.

According to the third aspect of the invention, the drive mechanism can be relatively simple in operating the lock bar. In particular, in a forklift having a structure in which the fork tilts with respect to the lift bracket, a hydraulic tilt cylinder for tilting the fork is often provided near the fork. Since the hydraulic cylinder for driving the lock bar can be constructed by utilizing it, the driving mechanism can be constructed very easily.

A fourth aspect of the present invention is the pallet lock device for a forklift according to the second or third aspect of the invention, wherein the fork and the lock bar are both positionally adjustable in the lateral direction of the vehicle body. provide.

According to the fourth aspect of the invention, for pallets having different sizes and various pallets having different hole positions,
The fork can be inserted securely, and the lock bar for pressing the pallet can be adjusted freely to avoid interference with the pallet. By setting the optimum position, a stable pallet lock action can always be achieved. it can.

As a fifth invention, in the second to fourth inventions, the lock bar is arranged between the forks and is inserted into the hole of the pallet together with the forks. A pallet lock device for a forklift, which is moved up and down to press the lower deck board of the pallet from the inside of the pallet.

According to the fifth aspect of the invention, in a pallet having deck boards on both the upper and lower sides, the upper deck board of the pallet is pressed from below by a fork, and the lower deck board of the pallet is pressed from above by a lock bar. By doing so, the pallet can be surely prevented from slipping. Further, in this way, since the lock bar is inserted inside the hole of the pallet, there is no obstacle in loading the load on the pallet, and the load can be loaded up to the full pallet.

As a sixth aspect of the invention, there is provided a pallet lock device for a forklift truck according to any one of the second to fifth aspects, wherein the drive mechanism is operated by a switch provided in a driver's seat of the forklift truck. .

According to the sixth aspect of the invention, the drive mechanism is operated electrically or hydraulically, and the switch for operating the drive mechanism is provided in the driver's seat of the forklift, so that the operator can lock the pallet. It can be done arbitrarily. In this case, as a matter of course, in the case of the electric type, electric wiring is provided, and in the case of the hydraulic type, a hose for supplying pressure oil is appropriately provided between the drive mechanism and the switch.

As a seventh invention, in the above inventions 2 to 5, a lift detection sensor for detecting that the fork has reached a predetermined lift is provided, and the drive mechanism responds to the output of the lift sensor. Provided is a pallet lock device for a forklift, which is characterized in that the pallet lock device operates.

According to the seventh aspect of the present invention, the fork is inserted into the pallet and lifted up to a predetermined height, whereby the lift detecting sensor is turned on to output an operation signal to the drive mechanism, and the lock bar is activated. Lock the palette. Therefore, the pallet is automatically locked even if the operator does not operate the switch. Since the forklift truck travels and turns with the pallet being lifted, by setting the height at which the lift detection sensor is turned ON appropriately, the pallet is always locked during traveling and turning. Slipping of the pallet on the fork is surely prevented. The above-mentioned lift detection sensor can be constituted by a limit switch or the like, which is fixed to either the mast or the lift bracket, and the dog for contacting the limit switch and turning it on is fixed to the other side. You can leave it. The height at which the above-described lift detection sensor is turned on can be freely set by appropriately setting the heights of these limit switches and dogs.

As an eighth invention, in the second to fifth inventions, a vehicle speed detection sensor for detecting that the forklift has reached a predetermined vehicle speed is provided, and the drive mechanism responds to the output of the vehicle speed detection sensor. Provided is a pallet lock device for a forklift, which is characterized in that the pallet lock device operates.

According to the eighth aspect of the invention, the vehicle speed detection sensor is turned on at the stage when the vehicle speed reaches a level at which the pallet slips on the fork, and outputs an operation signal to the drive mechanism.
This will automatically lock the pallet. The vehicle speed detection sensor can be easily configured by providing a rotation speed detection sensor on a traveling wheel of a forklift or a driving motor.

As a ninth invention, in the above-mentioned inventions of 2 to 5, a tilt angle detection sensor for detecting that the fork has reached a predetermined tilt angle is provided, and the drive mechanism is provided with the tilt angle detection sensor. Provided is a pallet lock device for a forklift, which operates according to output.

According to the ninth aspect of the invention, after the fork is inserted into the pallet, the tilt angle is tilted by a predetermined angle so that the tip end side of the fork is turned upward by the tilt device provided in the forklift at the tilt angle. The detection sensor turns on and outputs an operation signal to the drive mechanism,
This will automatically lock the pallet. Since a forklift normally travels and turns while tilting the pallet as described above, setting the angle at which the tilt angle detection sensor turns ON is appropriate to ensure that the pallet is locked during travel and turning. Therefore, the pallet sliding on the fork is surely prevented. The tilt angle detecting sensor is provided between the vehicle body and the mast in a forklift of a type in which the mast tilts with respect to the vehicle body, and in the forklift of a type in which the fork tilts with respect to the lift bracket. It can be easily constructed by providing an appropriate sensor or switch between the two.

As a tenth invention, in the above inventions 2 to 5, a turning state detection sensor for detecting a turning state of the vehicle body is provided, and the drive mechanism operates according to an output of the turning state detection sensor. Provided is a pallet lock device for a forklift, which is characterized by being a thing.

According to the tenth aspect of the invention, the pallet is in the most slippery state on the fork, that is, the turning state detection sensor is turned on when the vehicle body turns to output an operation signal to the drive mechanism, thereby automatically. Since the pallet is locked, slippage of the pallet on the fork is surely prevented. The turning state detection sensor must actuate the drive mechanism when turning the vehicle body.When determining the turning state of the vehicle body that produces this output, the steering wheel angle at the time of turning, the vehicle speed, the vehicle body acceleration, and the vehicle body are detected. Various elements such as the acting centrifugal force may be detected and used, or these elements may be combined by a computer to make a comprehensive determination.

As an eleventh invention, in the second to fifth inventions, the forklift is a reach type forklift in which the mast is supported so as to be movable in the longitudinal direction of the vehicle body, and Provided is a pallet lock device for a forklift, wherein a reach sensor for detecting movement is provided and the drive mechanism operates according to an output of the reach sensor.

According to the eleventh aspect of the invention, in the case where the forklift is a reach type forklift in which the mast is supported so as to be movable in the front-rear direction of the vehicle body, the reach sensor detects the front-rear movement of the mast and the drive mechanism is operated. The pallet is automatically locked by outputting an operation signal to.
Since a reach-type forklift truck is normally run / turned while the mast is pulled toward the vehicle body, that is, with the reach-in state, it is determined whether or not the vehicle can run / turn by installing the reach sensor. Therefore, it is possible to prevent the phenomenon that the pallet slides on the fork described above. Since the reach sensor only needs to detect the position movement of the mast in the front-rear direction, it can be easily constructed by providing a sensor for detecting the front-rear position of the mast or a member moving integrally with the mast at an appropriate position. can do.

As a twelfth invention, in the second to eleventh inventions, the surface of the lock bar that contacts the pallet is treated to increase the frictional force against the pallet. A pallet lock device for a forklift truck is provided.

According to the twelfth aspect of the present invention, the frictional engagement force between the lock bar and the pallet is increased, and the pallet sliding on the fork can be suppressed more effectively. Here, the process for increasing the frictional force means, for example, a process of forming irregularities on the lock bar or attaching rubber or a soft resin.

As the thirteenth invention, the above second to first inventions are provided.
In a second aspect of the present invention, there is provided a pallet lock device for a forklift, wherein the lock bar includes an elastic member.

According to the thirteenth aspect of the present invention, since the lock bar includes the elastic member, the pallet can be pressed by using the elastic force of the elastic member, and the pallet can be pressed with an appropriate force. It becomes possible to lock.

[0032]

1 shows a pallet lock device for a reach type forklift truck according to a first embodiment of the present invention, in which a lock means R for locking a pallet P inserted in a fork 10 is provided. It is provided on the lift bracket 6. Since the configuration other than the above is almost the same as the configuration shown in FIG. 18, the same portions are denoted by the same reference numerals and the description thereof will be omitted.

As shown in FIGS. 2 to 5, the locking means R is a pair of left and right suspension plates 14 which are suspended between the forks 10 on the support shaft 8 so as to be rotatable in the vertical directions c and d.
A drive mechanism 12 including a hydraulic or electric cylinder device such as a hydraulic cylinder or an electric cylinder fixed to a lower portion of the back surface of each suspension plate 14, and a lock bar 13.
The lock bar 13 includes a bar steel bar body 13a extending in the front-rear directions a and b, and a rising portion 13b extending upward from the base end of the bar body 13a.
Is driven by a fastening mechanism 15 such as bolts and nuts.
When the piston rod 12a is in the contracted state, the bar body 13a is substantially horizontal and the lower surface 13A thereof is positioned flush with or slightly above the lower surface 10a of the fork 10.

In FIGS. 2 and 4, reference numeral 17 denotes a support girder installed on the upper end of the lift bracket 6, and the support girder 1
The support shaft 8 is rotatably supported by bearings 18 fixed to both ends and the center of the shaft 7. Reference numeral 19 is a positioning pin that engages with the upper end recesses of each fork 10 and each suspension plate 14 through a through hole 20 penetrating the support girder 17. 21a, 21
Reference numeral b denotes a guide roller rotatably provided on both side surfaces of the lift bracket 6, which is brought into contact with the inner side surface and the bottom surface of each inner mast 5 to support the lift bracket 6 so that the lift bracket 6 can move up and down.

As shown in FIG. 6, a tumbler switch 22 for extending and retracting the drive mechanism 12 is provided in the driver's seat 1B of the vehicle body 1, and the switch 22 is moved from the neutral position O to the front and rear e, f. Drive mechanism 12 by rotating
The piston rod 12a is extended or contracted, and the operator can operate the switch 22 from the driver's seat 1B to arbitrarily lock the pallet P. In this case, if the drive mechanism is an electric type, electric wiring is provided, and if it is a hydraulic type, a pressure oil supply hose or the like is provided between the drive mechanism 12 and the switch 22, respectively.

In the above structure, when carrying out the cargo handling work, the forks 10 in the horizontal state are moved by advancing the masts 2 and 5 with the forks 10 lowered (see the chain double-dashed line in FIG. 1). The tip is inserted into the hole Pa of the pallet P (see the alternate long and short dash line in FIG. 1). In this case, fork 1
Since the front end portion of 0 and the lock bar 13 are at substantially the same horizontal level, the fork 10 and the lock bar 13 can be easily inserted into the hole Pa of the pallet P (FIG. 4).
reference).

Next, the load W is lifted through the pallet P by raising the fork 10, and the tilt device 1
By driving 1 to tilt the fork 10 upward c, the load W is tilted toward the backrest 9b side of the rotating frame 9.
Almost at the same time, the switch 22 is operated to operate the drive mechanism 1
By driving 2, the piston rod 12a is extended. As a result, the lock bar 13 is pressed against the lower deck board P2 of the pallet P to lock the pallet P (see FIG. 5). Then, by moving the vehicle body 1, the load W is conveyed to a predetermined position.

According to the above construction, the lock means R for locking the pallet P inserted into the fork 10 is provided on the lift bracket 6, so that the lock means R can be provided at an appropriate position near the fork 10. Moreover, since the lift bracket 6 always moves up and down along with the forks 10 along the masts 2 and 5, the relative positional relationship between the locking means R and the forks 10 does not change, so that the locking operation of the pallet P is ensured. It is possible to realize a pallet lock device that can be used for any purpose. Further, since the locking means R is not operated by a manual operation of an operator such as a lever operation or a pedal operation, but is operated by a switch 22, it is far from the lift bracket 6 from the driver seat 1B. It has become possible to operate.

Further, the drive mechanism 12 for actuating the lock bar 13 is arranged under the lift bracket 6, so that the position of the drive mechanism 12 is at the position of the fork 10.
To the pallet P, which is therefore inserted into the fork 10.
The mechanical connection between the lock bar 13 for pressing and the drive mechanism 12 can be easily configured.

In operating the lock bar 13, the drive mechanism 12 may be an electric type or a hydraulic type as described above, but the hydraulic tilt device 11 for tilting the fork 10 has already been provided in the vicinity of the fork 10. When provided, the hydraulic oil for driving the lock bar can be configured by using the pressure oil for the tilt device 11.

The upper deck board P1 of the pallet P
The pallet P can be surely prevented from slipping by pressing the fork 10 from below and the lower deck board P2 of the pallet P from above by the lock bar 13 (see FIG. 5). Further, in this way, the lock bar 13 is inserted inside the hole Pa of the pallet P, so that there is no obstacle in placing the load W on the pallet P, and the load W is loaded to the full pallet P. can do.

As shown in FIG. 2, a plurality of through holes 20 are provided in the support girder 17 of the lift bracket 6 at a predetermined interval k, and the positioning pin 19 is penetrated through the appropriate through holes 20. By engaging with the upper end recesses of each fork 10 and each suspension plate 14, respectively, both lock bars 1
It is possible to adjust the interval α between the three and the interval β between the forks 10 along the lateral direction of the vehicle body.

By doing so, the fork 10 can be surely inserted into the pallets P having different sizes and the pallets P having different positions of the holes Pa, and the lock bar 13 for pushing the pallet also has the position. Can be adjusted freely to avoid interference with the pallet P, and by setting the optimum position, a stable pallet locking action can always be achieved.

As shown in FIG. 7, the bottom surface 13A of the bar body 13a of the lock bar 13 is provided with a non-slip concave portion (or convex portion).
23, or as shown in FIG. 8, the bar body 13a
It is preferable to adhere a friction mat 24 having a large friction coefficient, such as rubber or a flexible resin, to the lower surface 13A.

By doing so, the frictional engagement force between the lock bar 13 and the pallet P is increased, and it becomes possible to more effectively suppress the sliding of the pallet P on the fork 10.

9 to 12 show a pallet lock device according to a second embodiment of the present invention, in which a cylindrical projection 25 is formed on the end face of the rising portion 13b of each lock bar 13.
a is provided in a protruding manner, and the annular ring 25b is externally fitted to the protruding portion 25a via the base end portion of the bar body 13a made of a coil spring (elastic member). The end portion is integrally connected to the rising portion 13b. Configurations other than the above are the same as those shown in FIGS.
Since it is almost the same as the embodiment described above, the same reference numerals are given to the same portions and the description thereof will be omitted.

According to the second embodiment described above, FIG.
As shown in FIG. 1, the tilt device 11 is driven to drive the fork 1
When 0 is tilted upward c, by driving each drive mechanism 12 to extend the piston rod 12a, the elastic force of the coil spring bar body 13a of each lock bar 13 is used to lower the pallet P. The deck board P2 can be pressed, and the pallet can be locked with an appropriate force.

In the first embodiment, the switch 2
Although the drive mechanism 12 is operated by 2 in FIG. 13, the invention is not limited to this.
The height detection sensor 27 shown in FIG. The lift detection sensor 27 includes a magnetic sensor body 27a fixed to one of the outer masts 2, and a lift bracket 6 (or a tilt bar 9) that is in the most lowered state facing the sensor body 27a.
The magnet 27b is fixed to a), and when the fork 10 is lowered, the magnet 27b faces the sensor body 27a [Fig. 13 (b)].
Solid line], from this state, when the fork 10 is inserted into the hole Pa of the pallet P, the lift bracket 6 and the tilt bar 9a are raised, and the pallet P is lifted by the fork 10, the magnet 27b moves upward and the sensor main body is moved. 27a, the drive mechanism 12 is operated by a control unit (not shown) including a CPU based on the output from the sensor main body 27a by the separation, and the piston rod 12a is extended. As a result, the lock bar 13 is pressed against the lower deck board P2 of the pallet P to lock the pallet P (see FIG. 5).

In this way, when the fork 10 is inserted into the pallet P and lifted up to a predetermined height, the lift detection sensor 27 is turned on, an operation signal is output to the drive mechanism 12, and the lock bar 13 is activated. Lock the pallet P. Therefore, the pallet P is automatically locked even if the operator does not operate the switch.

A vehicle speed detecting sensor 28 shown in FIG. 14 may be used instead of the switch 22. The vehicle speed detection sensor 28 is a sensor body 28a including a proximity switch provided on the upper surface of the drive motor 29 so as to face a rotary plate 30 such as a disc brake plate fixed to a rotary shaft 29a of a drive motor 29 that drives the drive tire 1a. When,
The sensor main body 28a comprises a gear 28b fixed to a rotary shaft 29a so as to face the sensor main body 28a. When the vehicle body 1 travels for cargo handling work, the rotation pulse of the drive motor 29 is read by the sensor main body 28a. A vehicle speed is detected by a control unit (not shown) including a CPU based on the output from the vehicle, and when the detected vehicle speed reaches a certain level or higher, the drive mechanism 12 is operated and the piston rod 12
Extend a. As a result, the lock bar 13 is pressed against the lower deck board P2 of the pallet P to lock the pallet P (see FIG. 5).

According to the above construction, when the pallet P reaches the vehicle speed at which the pallet P slips on the fork 10, the vehicle speed detection sensor 28 is turned on and outputs an operation signal to the drive mechanism 12, thereby automatically The pallet P is locked at. The vehicle speed detection sensor 28 can be easily configured by providing a rotation speed detection sensor on the drive tire (running wheel) 1a of the forklift or the drive motor 29 for driving.

A tilt angle detection sensor 31 shown in FIG. 15 may be used instead of the switch 22. The tilt angle detection sensor 31 includes a magnetic sensor body 31a fixed to the lift bracket 6 and a magnet 31b fixed to a protrusion plate 32 protruding from the tilt bar 9a so as to face the sensor body 31a. Down d
When tilted to the horizontal or horizontal, the magnet 31b
Is approaching the sensor main body 31a [see solid line in FIG. 15 (a)]. When the tilt device 11 tilts the fork 10 upward through the tilt bar 9a from this state, the magnet 31b also moves upward c. Sensor body 3
1a (see the solid line in FIG. 15B), the drive mechanism 12 is actuated by a control unit (not shown) including a CPU based on the output from the sensor body 31a to extend the piston rod 12a. . This allows
The lock bar 13 is pressed against the lower deck board P2 of the pallet P to lock the pallet P (see FIG. 5).

According to the above-mentioned structure, after the fork 10 is inserted into the pallet P, the tilting device 11 provided on the forklift tilts the rear side of the vehicle body, that is, the tip side of the fork 10 at a predetermined angle so as to be raised. The tilt angle detection sensor 31 is turned on and outputs an operation signal to the drive mechanism 12, whereby the pallet P is automatically locked.

Further, the turning state detecting sensor 33 shown in FIG. 16 may be used in place of the switch 22. The turning state detection sensor 33 includes a sensor main body 33a including a proximity switch fixed to the vehicle body 1 by approaching a large gear 35 fixed to the support frame 34 of the drive tire 1a, and the sensor main body 33.
Magnet 33b fixed to the large gear 35 facing a
The large gear 35 is meshed with the small gear 36 which is interlocked with the handle, and when the drive tire 1a is moved straight in the front-rear direction a, b, the magnet 33b faces the sensor body 33a. In this state (see the solid line in FIG. 16 (b)), the vehicle body 1 is advanced a from this state to insert the fork 10 into the hole Pa of the pallet P, and the lift bracket 6 and the tilt bar 9a are raised to raise the fork 10. After the pallet P is lifted by, the vehicle body 1 is moved backward b, the handle is turned to the right or left, and the large gear 35 is rotated via the small gear 36, so that the drive tire 1a is turned to the left or right. When switched, the magnet 33b is separated from the sensor body 27a [see the phantom line in FIG. 16 (b)], and the separation causes the magnet 33b to separate from the sensor body 33a. Drive mechanism 12 by the control unit comprising a CPU (not shown) is actuated on the basis of the output, to extend the piston rod 12a. As a result, the lock bar 13 is pressed against the lower deck board P2 of the pallet P to lock the pallet P (see FIG. 5).

According to the above structure, the pallet P is in the most slippery state on the fork 10, that is, the turning state detection sensor 33 is turned on when the vehicle body 1 turns, and an operation signal is output to the drive mechanism 12. Since the pallet P is locked, the slip of the pallet P on the fork 10 is reliably prevented.

The reach sensor 37 shown in FIG. 17 may be used instead of the switch 22. This reach sensor 37
Has one outer mast 2 (or straddle leg 1
A) A magnetic sensor body 37a fixed to the sensor body 37a, and a magnet 37b fixed to the straddle leg 1A (or the outer mast 2) facing the sensor body 37a. By advancing a to insert the fork 10 into the hole Pa of the pallet P, the magnet 37b is separated from the sensor main body 37a, and the separation causes the magnet 37b to output a signal from the sensor main body 37a. Drive mechanism 12 is actuated by (No.) to extend the piston rod 12a. As a result, the lock bar 13 is pressed against the lower deck board P2 of the pallet P to lock the pallet P (see FIG. 5).

According to the above structure, when the forklift is a reach type forklift in which the masts 2 and 5 are movably supported in the front-rear directions a and b of the vehicle body 1, the front-rear movement of the masts 2 and 5 is reached by the reach sensor. 37 detects and outputs an operation signal to the drive mechanism 12, whereby the pallet P is automatically locked.

In the above first and second embodiments, the case where two lock bars 13 are provided has been described as an example, but only one lock bar 13 or three or more lock bars 13 may be provided. Further, although the bar-shaped body 13a is shown as a bar, it may be hook-shaped. In the case of a rod shape, it is convenient for press-contacting the pallet P, and in the case of a hook shape, it is convenient for engaging with the irregularities or holes of the pallet P. Further, the reach type forklift has been described as an example, but the present invention is not limited to this and can be applied to various forklifts.

[0059]

According to the first aspect of the present invention, since the lock means for locking the pallet inserted into the fork is provided on the lift bracket, the lock means can be provided at an appropriate position near the fork. Further, since the lift bracket always moves up and down along with the fork along the mast, the relative positional relationship between the lock means and the fork does not change, and therefore, the pallet locking device capable of reliably performing the pallet locking operation is realized. can do. Further, the locking means is not operated by a manual operation of an operator such as a lever operation or a pedal operation,
Since it is operated electrically or hydraulically, even if it is installed on the lift bracket far from the driver's seat, it can be operated reliably.

According to the second aspect of the invention, since the drive mechanism for operating the lock bar is arranged below the lift bracket, the position of the drive mechanism approaches the fork,
Therefore, the mechanical connection between the lock bar for pressing the pallet inserted in the fork and the drive mechanism can be easily configured.

According to the third aspect of the invention, the drive mechanism can be relatively simple in operating the lock bar. When a hydraulic tilt cylinder for tilting the fork is provided in the vicinity of the fork, it is possible to configure the lock bar driving hydraulic cylinder by using the pressure oil for the tilt cylinder.
The drive mechanism can be constructed extremely easily.

According to the fourth aspect of the invention, the fork can be reliably inserted into pallets having different sizes and various pallets having different hole positions, and the position of the pallet pressing lock bar can be freely adjusted. By doing so, interference with the pallet can be avoided, and by setting the optimum position, a stable pallet locking action can always be achieved.

According to the fifth aspect, in a pallet having deck boards on both upper and lower sides, the upper deck board of the pallet is pressed from below by a fork, and the lower deck board of the pallet is pressed from above by a lock bar. As a result, the pallet can be surely prevented from slipping. Further, in this way, since the lock bar is inserted inside the hole of the pallet, there is no obstacle in loading the load on the pallet, and the load can be loaded up to the full pallet.

According to the sixth aspect of the invention, since the switch for operating the drive mechanism is provided in the driver's seat of the forklift, the operator can arbitrarily perform the pallet locking operation.

According to the seventh invention, by inserting the fork into the pallet and lifting up to a predetermined height,
The lift detection sensor is turned on to output an operation signal to the drive mechanism, and the lock bar locks the pallet. Therefore, the pallet is automatically locked even if the operator does not operate the switch.

According to the eighth aspect of the invention, the vehicle speed detection sensor is turned on at the stage when the vehicle speed has reached a level at which the pallet slips on the fork, and an operation signal is output to the drive mechanism. Is locked.

According to the ninth aspect of the invention, after the fork is inserted into the pallet, the tilting device provided on the forklift is tilted by a predetermined angle so that the rear side of the vehicle body, that is, the fork tip side is tilted by a predetermined angle. The tilt angle detection sensor is turned on to output an operation signal to the drive mechanism, whereby the pallet is automatically locked.

According to the tenth aspect of the invention, when the vehicle body is turning, the turning state detection sensor is turned on and outputs an operation signal to the drive mechanism, whereby the pallet is automatically locked, so that the pallet on the fork is locked. The slippage is surely prevented.

According to the eleventh aspect, when the forklift is a reach type forklift, the reach sensor detects the forward and backward movement of the mast and outputs an operation signal to the drive mechanism, whereby the pallet is automatically locked. To be done.

According to the twelfth aspect, the frictional engagement force between the lock bar and the pallet is increased, and the pallet sliding on the fork can be suppressed more effectively. .

According to the thirteenth invention, since the lock bar includes the elastic member, the pallet can be pressed by the elastic force of the elastic member, and the pallet lock can be performed with an appropriate force. Is possible.

[Brief description of drawings]

FIG. 1 is a side view showing a pallet lock device for a reach type forklift according to a first embodiment of the present invention.

FIG. 2 is a front view of the same.

FIG. 3 is a perspective view of the main part.

FIG. 4 is a view on arrow AA of FIG.

FIG. 5 is a longitudinal sectional view of the main portion of the fork tilting state.

FIG. 6 is a perspective view of the reach type forklift truck.

FIG. 7 is a partially cutaway side view showing an example of a modification of the lock bar.

FIG. 8 is a partially cutaway side view showing another modification of the lock bar.

FIG. 9 is a perspective view of essential parts showing a pallet lock device for a reach type forklift truck according to a second embodiment of the present invention.

FIG. 10 is a view as seen from the arrow BB in FIG.

FIG. 11 is a view taken along the line CC of FIG.

FIG. 12 is a vertical cross-sectional view of the main part of the fork tilting state.

13 (a) and 13 (b) are a horizontal sectional view and a vertical sectional view of a main part showing a lift detection sensor.

14 (a) and 14 (b) are a rear view and a perspective view of an essential part showing a vehicle speed detection sensor.

15A and 15B are vertical cross-sectional views of a tilt angle detecting sensor before and after tilting of a main part.

16 (a) and 16 (b) are a rear view and a perspective view of an essential part showing the turning state detection sensor.

17 (a) and 17 (b) are a front view and a side view of a main part showing a reach sensor.

FIG. 18 is a side view showing a conventional example.

[Explanation of symbols]

1 car body 2,5 mast 6 Lift bracket 10 forks 11 Tilt device 13 Rock bar 23 recess 24 Friction mat 27 Lift detection sensor 28 Vehicle speed detection sensor 31 Tilt angle detection sensor 33 Turning state detection sensor 37 Reach sensor R lock means a, b front-back direction P pallet Pa pallet hole Upper deck board of P1 pallet Lower deck board of P2 pallet

Claims (13)

[Claims] 1. A forklift having a mast which is erected on a vehicle body, a lift bracket which is moved up and down along the mast, and a fork which is supported by the lift bracket, and which is electrically or hydraulically operated to be inserted into the fork. A pallet lock device for a forklift, characterized in that lock means for locking the pallet is provided on the lift bracket. 2. The lock means comprises a lock bar for pressing a pallet inserted in the fork and a drive mechanism for operating the lock bar, and the drive mechanism is disposed below the lift bracket. The pallet lock device for a forklift according to claim 1, wherein: 3. The pallet lock device for a forklift according to claim 2, wherein the drive mechanism includes a hydraulic or electric cylinder device. 4. The pallet lock device for a forklift according to claim 2, wherein the fork and the lock bar are both positionally adjustable in the lateral direction of the vehicle body. 5. The lock bar is arranged between the forks, and is inserted into the hole of the pallet together with the forks, and is vertically moved by the drive mechanism to move the lower deck board of the pallet from the inside of the pallet. The pallet lock device for a forklift according to any one of claims 2 to 4, wherein the pallet lock device presses. 6. The pallet lock device for a forklift according to claim 2, wherein the drive mechanism is operated by a switch provided in a driver's seat of the forklift. 7. A lift detection sensor for detecting that the fork has reached a predetermined lift is provided, and the drive mechanism operates according to an output of the lift sensor. A pallet lock device for a forklift according to any one of claims 2 to 5. 8. A vehicle speed detection sensor for detecting that the forklift has reached a predetermined vehicle speed is provided, and the drive mechanism operates according to an output of the vehicle speed detection sensor. 5. A pallet lock device for a forklift according to any one of 5 to 5. 9. A tilt angle detection sensor for detecting that the fork has reached a predetermined tilt angle, and the drive mechanism operates according to the output of the tilt angle detection sensor. Claim 2
5. A pallet lock device for a forklift according to any one of 5 to 6. 10. A turning state detection sensor for detecting a turning state of the vehicle body is provided, and the drive mechanism operates according to an output of the turning state detection sensor. Forklift pallet lock device described in. 11. A forklift truck is a reach type forklift truck in which the mast is movably supported in the front-rear direction of the vehicle body, and a reach sensor for detecting the front-rear movement of the mast is provided, and the drive mechanism is provided. 6. The pallet lock device for a forklift according to claim 2, wherein the pallet lock device operates according to an output of the reach sensor. 12. The pallet lock device for a forklift according to claim 1, wherein a surface of the lock bar that comes into contact with the pallet is treated to increase a frictional force with respect to the pallet. 13. The pallet lock device for a forklift according to claim 1, wherein the lock bar includes an elastic member.