JPH10109898A - Lift height regulating device for forklift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the lift height regulating device for a forklift, which can maintain a lift height regulating mode at all times. SOLUTION: A lift height regulating stopper 3 is mounted on the outer surface of an outer mast is such a way that it can be rotated in the horizontal direction, and the stopper 3 is so designed that it can be operated by an air cylinder 6 fixed to the outer mast. The air cylinder 6 is made a single acting type, and a spring 9 energizing a rod 6a to the projected direction at all times, is housed it its main body. When pressure air is fed to the air cylinder 6, the rod 6a is pulled in so as to allow the stopper 3 to be rotate to a regulation releasing position where the stopper of a lift bracket does not abut, and when pressure air is exhausted, the stopper 3 is so designed as to be rotted to a lift height regulating position where the stopper of the lift bracket abuts by projecting the rod 6a by means of the spring 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to automatically stop the lifting operation of a loading device such as a forklift when the height of the loading device reaches a predetermined regulation height during a cargo handling operation. And a lift control device for a forklift.

[0002]

2. Description of the Related Art Conventionally, when a container is loaded and unloaded using a forklift between a wagon stopped at a railway line or the like and a loading / unloading station, for example, an operation mode in which the container passes under a railway overhead line is used. Become. For this reason, forklifts used for cargo handling work in places subject to restrictions such as under overhead lines, automatically raise the loading device when the height of the loading device such as a fork reaches the regulated height. A lift control device for stopping the engine is provided. Such a lift control device is disclosed in, for example, JP-A-7-24239.
No. 7 discloses this.

As shown in FIG. 5, the lift control device described in the above publication has a 90 ° reversing type lift control stopper 42 provided on the outer surface of an outer mast 41 which is a fixed mast. Hydraulic cylinder 43 (or electromagnetic cylinder) operated by lever or switch operation at
Thus, the fixed stopper 45 provided on the lift bracket 44 can be switched between a lift restriction position where it can abut and a restriction release position where it does not abut. And
When the lift-height restricting stopper 42 is switched to the lift-height restricting position, the limit switch 47 is turned on by the arm 46 provided on the stopper 42, and the automatic stop sensor 48 becomes detectable.

Therefore, during the cargo handling operation in the lift regulation mode in which the lift regulation stopper 42 is switched to the lift regulation position, the height of the loading device (not shown) attached to the lift bracket 44 reaches the regulation height. Then, the sensor 48 detects the dog 49 provided on the lift bracket 44, and shuts off the hydraulic circuit of the lift cylinder (not shown) to stop the lifting operation of the lift bracket 44. When the sensor 48 malfunctions, the fixed stopper 45 of the lift bracket 44 abuts on the lift regulating stopper 42 to stop the ascent mechanically.

[0005]

According to the above-described conventional lift restricting device, it is possible to easily switch between the lift restricting mode and the release mode in the driver's cab, and to quickly change the cargo handling mode. Although it has a feature, there is a problem that when the switching means of the lift regulating stopper 42 fails, the lift regulating mode which is an original function of the apparatus cannot be secured.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide a forklift lift height control device capable of always maintaining a lift height control mode. is there.

[0007]

Means for Solving the Problems In order to solve the above problems, the present invention is configured as follows. In other words, the invention according to claim 1 is a restriction release position that is provided on one of the mast and a lift bracket that moves up and down along the mast, and that is not in contact with a lifting height restriction position that comes into contact with an engagement portion provided on the other. And a biasing means for urging the stopper to always be at the height regulating position, and the stopper is moved to the regulation releasing position against the urging force of the urging means. Operable restriction canceling means.

[0010] According to the first aspect of the present invention, since the lift restricting stopper is always held at the lift restricting position by the urging means, the cargo handling operation is performed in the lift restricting mode. When the stopper is moved to the restriction release position by operating the restriction release means, the cargo handling operation can be performed in the release mode. In other words, according to the first aspect of the present invention, the stopper for regulating the lift is held at the position for restricting the lift unless the restriction canceling means is actuated. In addition, the original function of the lift control device can be maintained.

In this case, when the regulation release means is provided, as in the second aspect of the present invention, in the lift regulation apparatus of the first aspect, the restriction release means is constituted by an air cylinder operable in a driver's seat. It is desirable. In such a configuration, even if an air leak occurs due to a failure of the operation circuit of the air cylinder, the stopper for height regulation is held at the height regulation position, and the original function of the height regulation device is maintained. In addition to being able to easily switch between the lift control mode and the release mode in the driver's seat, it is possible to change the cargo handling form quickly, and the use of air contaminates the surroundings due to air leakage. There is no fear.

Further, as in the invention of claim 3, claim 1
In the lifting height control device, the restriction release operation means may be constituted by a cable which can be manually operated in a driver's seat. With such a configuration, it is possible to provide a simpler and less expensive regulation releasing means than the second aspect of the invention.

According to a fourth aspect of the present invention, in the forklift lifting height control device according to the first aspect, a lifting height detecting means for detecting that the lift bracket approaches the regulated lifting height, and the lifting height detecting means. It is desirable to have a lifting height informing means that is activated based on the detection signal of the above. With such a configuration, as in the case of the first aspect of the present invention,
Since the stopper can be held at the height restriction position as long as the restriction release means is not operated, even if the restriction release means breaks down, the original function of the lift restriction device can be maintained, and the load mounted on the lift bracket can be maintained. When the device approaches the regulated height, the driver can be notified of the fact and call attention.

Also, as in the invention of claim 5, claim 1
In the lift height control device for a forklift described above, a restriction release detection means for detecting that the lift restriction stopper is switched to a restriction release position, and a release notification actuated based on a detection signal of the restriction release detection means. Means. With such a configuration, the stopper can be held at the lift restriction position as long as the restriction release means is not operated, as in the case of the first aspect of the invention. In addition to maintaining the original function of the device, the driver can be alerted to the fact that the lift control device is in the release mode to call attention.

[0013]

Embodiments of the present invention will be specifically described below with reference to the drawings. First, a first embodiment will be described with reference to FIGS. FIG. 1 and FIG. 2 are explanatory views showing a lift control device according to the present embodiment, and FIG.
FIG. 4 is an explanatory view of an operation mode of a lifting height regulating stopper. As shown in FIGS. 1 and 2, substantially U-shaped brackets 2 are fixed to the outer surfaces of outer masts 1, which are left and right fixed masts, which are installed at the front part of the body of the forklift. The restricting stopper 3 is rotatably mounted around the vertical axis through a pin 4 within a range of about 90 °, and the rotational range is restricted by, for example, a stopper member.

On the outer surfaces of the left and right outer masts 1,
Arms in which air cylinders 6 are mounted in a substantially horizontal position via brackets 5 at positions slightly higher than the lifting height stoppers 3, respectively, and the ends of rods 6a of the air cylinders 6 are fixed to the upper surfaces of the stoppers 3 in a protruding manner. 7 is connected via a link 8 to the distal end.

As shown in FIG. 3, the air cylinder 6 is a single-acting type that supplies pressurized air to only one side of the piston 6b, and urges the rod 6a in the projecting direction on the opposite side of the piston 6b. The spring 9 is housed. That is, when the pressurized air of the air cylinder 6 is exhausted, the stopper 3 serving as an engaging portion provided on the lift bracket 10 comes into contact with the lifting height regulating stopper 3 by the projecting operation of the rod 6 a by the spring force of the spring 9. The rod 6a is rotated to a possible lifting height restriction position, and is rotated to a restriction release position where the stopper 11 does not come into contact with the rod 6a when the pressurized air is supplied.

Therefore, the spring 9 constitutes urging means for urging the stopper 3 for regulating the lift so as to always be at the position for regulating the lift, and the air cylinder 6 serves as the stopper 3 for regulating the lift.
Constitutes a regulation release means that operates the restriction release position. The air cylinder 6 is operated by an air switch 14 provided on an operation panel 13 in the cab 12. That is, the air switch 14 pressurizes the air cylinder 6 by operating an electromagnetic switch valve (not shown) provided in a cylinder operating circuit that connects the air cylinder 6 and an air tank (not shown) mounted on the body of the forklift. It controls the supply and exhaust of air.

The lift bracket 10 is configured to be lifted and lowered along a mast via a lift chain 15 by a lift cylinder (not shown), and a fork or a container spreader as a loading device (not shown) is mounted on the front surface thereof. Is done. On the rear surface of the outer mast 1, when the lift bracket 10 approaches the height regulation position, a matching mark 1 as a regulation height indicating means that matches a specific position of the lift bracket 10, for example, a lower end portion.
6 (for example, a fluorescent color label or paint) is provided so that an operator in the cab 12 can visually check the regulation height.

In addition to enabling visual confirmation, a lift bracket 1 is provided on the outer surface of the outer mast 1 in order to electrically detect that the loading device has approached the height regulation height.
The sensor 17 is provided as a regulation height detecting means capable of detecting the dog 18 provided at 0. And the sensor 18
When the dog 18 is detected, the lamp 19 attached to the outer surface of the outer mast 1 is turned on, and the chime 20 in the cab 12 is electrically connected so that the chime 20 sounds. The lifting height notification means for notifying the approach of the loading device to the regulated lifting position is configured.

Furthermore, on the outer surface of the outer mast 1,
A limit switch 2 serving as a regulation release detecting means that is actuated by an operation arm 21 provided on the lift 3 when the lift regulation stopper 3 is rotated to the regulation release position.
2 are installed. When the limit switch 22 is actuated, the pilot lamp 23 in the cab 12 is turned on, the gentle buzzer 24 is continually sounding, and the red rotary light 25 mounted on the ceiling of the cab 12 is actuated. The pilot lamp 23, the buzzer 24, and the red rotating light 25 are electrically connected to notify the driver and the surroundings of the restriction release notification means. doing. In addition, the stopper 3 in the state where it is rotated to the regulation release position is easily applied to the driver's eyes by applying, for example, red fluorescent paint or the like to its rear surface.

The automatic lifting and stopping device according to the present embodiment is constructed as described above, and the air changeover switch 14 is normally set to the air exhaust side. At this time, the rod 6a is protruded by the spring 9 in the air cylinder 6, and the lifting-height regulating stopper 3 is shown in FIGS.
(A), the stopper 11 of the lift bracket 10 has been turned to a lift-restricted position where the stopper 11 can abut.

Therefore, at the time of the cargo handling operation in the lift control mode in which the lift control stopper 3 is rotated to the lift control position,
When the loading device approaches the lifting height regulation position, the driver can visually confirm the approaching state in the driver's cab 12 with the alignment mark 16, and at the position corresponding to the alignment mark 16 for detecting the regulation height. Since the sensor 17 detects the dog 18 of the lift bracket 10 and the lamp 19 is turned on and the chime 20 in the cab 12 sounds, the driver can visually and audibly recognize that the loading device has reached the regulation height. Can be confirmed by

When the driver confirms that the loading device has approached the lifting position, the driver then performs an operation to stop the lifting operation. If the lifting stop operation is delayed, the driver may lift the lifting bracket 10. The stopper 11 contacts the lower surface of the lift regulating stopper 3 to stop the ascent operation mechanically.

On the other hand, when the air changeover switch 14 is switched to the air supply side, the pressurized air in the air tank is supplied into the air cylinder 6, so that, as shown in FIGS. The rod 6a is retracted against the spring 9, and the lift regulating stopper 3 is rotated to the regulation releasing position. At this time, the back of the stopper showing the red fluorescent color
The driver can visually confirm that the mode has been switched to the regulation release mode because the driver is directed to the second side.

On the other hand, when the stopper 3 is turned to the regulation release position, the operating arm 21 contacts the limit switch 22 to operate it, so that the pilot lamp 23 in the cab 12 is turned on, Since the buzzer 24 sounds, the driver can also visually and audibly confirm that the stopper 3 is in the regulation release state. Further, since the red rotating light 25 is operated, it is possible to notify surrounding workers and the like that the regulation is released.

As described above, according to the lift control device according to the present embodiment, it is possible to easily switch between the lift control mode and the restriction release mode by operating the cab 12 and quickly change the cargo handling mode. Of course, in particular, since the lift regulating stopper 3 is always urged toward the lift regulating side by the spring 9, the operation circuit of the air cylinder 6 may fail. In addition, even if air leakage occurs, the lifting height regulation mode can be maintained. Therefore, it is possible to maintain the original function of the lifting height control device, and it is possible to carry out the cargo handling work at a place where the lifting height is restricted such as under the overhead line without any trouble.

Further, when air pressure is used, the apparatus becomes cleaner against leakage due to damage to piping compared to oil pressure, and the problem of soiling surroundings is eliminated. In addition, since the lift is regulated by mechanical contact between the stopper 11 of the lift bracket 10 and the stopper 3 for regulating the lift, the lift of the lift bracket 10 is electrically detected, and the detection signal is used to control the hydraulic circuit of the lift cylinder. The number of failures is smaller than in the conventional system in which the valve is electrically controlled to stop the ascending operation.

An alignment mark 16 for indicating a lift restriction position is provided on the rear surface of the outer mast 1 which is easy to see from the cab 12.
In addition to being able to visually check the regulation height, when the loading device approaches the regulation height, the driver turns on the lamp 19 and also sounds the chime 20. The height regulation can also be known.

Furthermore, in the present embodiment, when the lifting height restricting stopper 3 is switched to the restriction releasing mode, the pilot lamp 23 in the cab 12 is turned on and the buzzer 24 is sounded to visually and audibly. The driver can be notified, and the surroundings can be alerted by the operation of the red rotating light 25.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, a helical spring 27 is provided as urging means for urging the lift-regulating stopper 3 attached to the bracket 2 so as to be horizontally rotatable within a range of 90 ° so as to always be at the lift-regulated position. On the other hand, a wire cable 29 is employed as a restriction release means for operating the stopper 3 to the restriction release position against the urging force of the helical spring 27.

One end of the helical spring 27 has a stopper 3
The other end is locked to the bracket 2, and the stopper 3 is always urged to the height regulation side. On the other hand, the wire cable 29 is disposed between the stopper 3 and the cab 12, and one end of a cable outer 29 a (tube) is connected to the wire bracket 30 on the mast side, and the other end is an operation panel in the cab 12. 13 (or a wire bracket), one end of a cable inner 29b is connected to the stopper 3, and an operation knob 31 is provided at the other end.

A hook 32 on which a knob 31 can be hooked is provided on a pillar or a wall surface of the cab 12. The other detection means, notification means, and the like are configured and operate in the same manner as in the above-described first embodiment.

Therefore, according to the second embodiment configured as described above, the wire cable 29
By operating the knob 31, the lift regulating stopper 3 is switched between a lift regulating position (shown by a solid line) where the stopper 11 of the lift bracket 10 abuts and a regulation release position (shown by a virtual line) which does not abut. The restriction release state can be held by hooking the knob 31 on the hook 32.

Also, even if the wire cable 29 is broken, the stopper 3 for regulating the lift, which is always urged to the height-regulating side by the helical spring 27, is held at the lift-regulating position. The original function as a high-regulation device is maintained, and there is no hindrance to cargo handling work in places subject to height regulation. In particular, in the case of the wire cable type, the structure is simple and effective for cost reduction, and since it is mechanical, there is little failure and a highly reliable lifting control device.

The present invention is not limited to the above-described embodiment, and various modifications can be made as follows without departing from the gist of the present invention. (1) As a notification method when the loading device approaches the regulated height, the lift of the loading device is detected stepwise by a plurality of sensors, and according to each of the stages, for example, the first stage is to call attention. May be notified by a chime, and then by a buzzer in a warning sense.

(2) Before the stopper 11 of the lift bracket 10 comes in contact with the stopper 3 for regulating the lift, the height of the loading device is electrically detected by a sensor, and the hydraulic pressure of the lift cylinder is determined based on the detection signal. The lifting operation of the lift bracket 10 is stopped by operating a valve of the circuit, and the mechanical stop due to the contact between the lift regulating stopper 3 and the stopper 11 is performed in the event that the regulated lift detecting sensor fails. May be changed to a form such as ensuring the safety of the vehicle.

(3) As the urging means for urging the lift regulating stopper 3 toward the lift regulating side, a magnetic force generated by a permanent magnet may be used instead of the springs 9 and 27. The switching method of the lifting height stopper 3 may be changed from the horizontal rotation method to the linear advance / retreat method. (4) The stopper on the outer mast 1 side may be a fixed type, and the stopper on the lift bracket 10 side may be a switching type. (5) The restriction release means is not limited to the air cylinder 6, but may be a hydraulic cylinder or an electromagnetic cylinder as long as it is a single-acting type.

[0037]

As described in detail above, according to the present invention,
Since the lift regulating stopper is always held at the lift regulating position, the lift regulating mode can be maintained even if the regulation canceling means breaks down. Therefore, the original function of the lift control device can be maintained, and cargo handling work in a place subject to the lift control, such as under overhead lines, can be performed without any trouble.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a state in which a lift control device according to a first embodiment controls a lift.

FIG. 2 is an explanatory diagram showing a state in which the lifting regulation device is released from regulation.

FIGS. 3A and 3B are explanatory diagrams of an operation mode of a lifting-height restriction stopper, wherein FIG. 3A shows a state when the height is restricted, and FIG.

FIG. 4 is an explanatory view showing a lift control device according to a second embodiment.

FIG. 5 is an explanatory view showing a conventional lift control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Outer mast 3 ... Lift height control stopper 6 ... Air cylinder as restriction release means 9 ... Spring as urging means 10 ... Lift bracket 11 ... Stopper

Claims (5)

[Claims] 1. A lift height restricting position which is provided on one of a mast and a lift bracket which moves up and down along the mast and which comes into contact with an engaging portion provided on the other, and which can be switched to a restriction releasing position which does not come into contact. A stopper for restricting the lift, a biasing means for biasing the stopper to be always at the lift-restricting position, and a restriction capable of operating the stopper to the restriction releasing position against the biasing force of the biasing means. A lift control device for a forklift having a release means. 2. The forklift lift restriction device according to claim 1, wherein said restriction release means comprises an air cylinder operable in a driver's seat. 3. The forklift lift restriction device according to claim 1, wherein said restriction release means comprises a cable which can be manually operated in a driver's seat. 4. A lift height control device for a forklift according to claim 1, wherein said lift height detection means detects that said lift bracket approaches a restriction height, and operates based on a detection signal of said lift height detection means. Lift control device for a forklift, comprising a lift height notification means. 5. The lift-restricting device for a forklift according to claim 1, wherein the lift-restricting stopper is switched to a restriction-releasing position, and a detection signal from the restriction-release detecting device. Lift restricting device for a forklift, comprising: a release notifying means operated based on the information.