JPH0617837Y2 - Safety device for forklift with remote control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a safety device for a forklift with a remote control device.

(Prior Art) FIG. 3 and FIG. 4 show that a vehicle body 1 is equipped with a normal driver's seat 2 and also a lifting / lowering mounting side that moves up and down along a mast 3, specifically, a backrest 4 for operating a lift cylinder. 1 shows a reach type forklift truck equipped with a remote control device 5. This type of forklift is operated at the driver's seat when performing normal fork work, and for example, when performing shelf work or the like, a remote control bucket 7 as shown by a virtual line is attached to the fork 6 and the remote control is operated. Bucket 7
An operator gets in and operates the remote controller 5 to move up and down.

The remote control bucket 7 is attached by inserting the fork 6 in the lifting device into a sheath fork 8 integrally provided at the bottom of the bucket. Further, the remote control device 5 is specifically composed of a remote control valve for operating a lift cylinder operated by a lever, and when the switching valve for operating position switching in the hydraulic circuit operated on the driver's side is switched to the remote control side. Only the lift cylinder can be operated.

(Problems to be solved by the invention) By the way, since the remote control bucket 7 is a considerable heavy object, and the weight of the operator or the pallet mounted on the sheath fork 8 is added to this weight, the remote control bucket 7 is allowed. The load is kept considerably lower than the allowable load during normal standard fork work. However, conventionally, a device for preventing overload at the time of remote control is not provided, and it is possible to use beyond overload. In other words, when using the remote control, the operator loads a load exceeding the allowable load onto a bucket or a pallet attached to it and lifts it up, or at the lifted position during a picking operation to load a load such as a shelf into a bucket or pallet It may cause overload, which may result in loss of vehicle stability.

Therefore, in view of the above problems, an object of the present invention is to provide a safety device for a forklift with a remote control device, which is prohibited from being used in an overloaded state during remote control.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a driver's seat on the vehicle body side, a remote control device for operating a lift cylinder on the lifting device side, and a hydraulic pump for cargo handling. In a forklift driven by a motor, a load sensor that detects the load acting on the lifting device and outputs a signal when the set load is exceeded, and a switching valve provided in the hydraulic circuit of the cargo handling actuator for switching the operating position. Means for detecting switching to the remote control side, and means for stopping the motor when a signal is output from the load sensor in a state where the switching detection to the remote control side by the means is performed.

(Operation) With the safety device of the present invention configured as described above, when the loading load exceeds the allowable load during the cargo handling operation by operating the remote control device, the lifting operation of the lifting device is stopped or disabled. Prompts the operator's attention.

(Embodiment) An embodiment of the present invention will be specifically described below with reference to the drawings. The forklift with a remote control device is a reach type vehicle that uses a battery as a drive source, and the overall configuration of the vehicle is the same as that of the conventional vehicle shown in FIGS.
Is equipped with a normal driver's seat 2, and a backrest 4 in the lifting device is equipped with a remote control device 5.

FIG. 2 shows a hydraulic circuit of the cargo handling system. Reference numeral 9 in the figure denotes a hydraulic pump driven by an electric motor 10, and hydraulic oil pumped from a tank 11 is supplied to each hydraulic actuator via a cargo handling control valve 12. The cargo control valve 12 is a four-way type, and includes a lift switching valve 13, a reach switching valve 14 from the hydraulic pump 9 side.
The tilt changeover valve 15 and the operation position changeover changeover valve 16 are arranged in this order, and the lift cylinder 17, the reach cylinder 18, and the lift cylinder 18 are changed by the changeover operations of the lift, reach, and tilt changeover valves 13, 14, 15. The operation of the tilt cylinder 19 is controlled. The above-described cargo handling control valve 12 is provided on the vehicle body side, and all the switching valves are operated in the driver's seat 2. Especially, when the switching valve 16 for switching the operating position is switched to the remote control side A. It is adapted to be held at the switching position by an appropriate locking means (not shown).

On the other hand, the remote control device 5 mounted on the backrest 4 is specifically composed of a remote control valve 20 for operating a lift cylinder operated by a lever, and the switching valve 16 for switching the operating position is switched to the remote control side A. Only in this case, the lift cylinder 17 can be moved up and down.

Also, an electric motor 1 for driving the hydraulic pump 9
0 is activated by 4 switches as shown in Fig. 1.
It is controlled to stop. That is, the motor drive circuit 21 includes four switches 22, 23, 24, 2
5 are connected in parallel, and the electric motor 10 is driven by turning on any one of them. As shown in FIG. 2, the switches 22, 23, 24 and 25 are the switching valves 13, 14, 1 for the lift, the reach and the tilt.
5 and the remote control valve 20 are arranged so as to be operated one by one, and the switching valves 13 and 1 described above are arranged.
4, 15 or the remote control valve 20 is held in the off position at the neutral position in the figure, and is turned on by switching to the operating position (however, in the case of the lift switching valve 13 and the remote control valve 20, the rising side).

Next, a safety device for preventing overload at the time of remote control will be described. As shown in FIG. 2, a pressure sensor 27 as a load sensor for detecting a load is attached at an arbitrary position of the operation pipe line 26 for the lift cylinder 17, and the pressure sensor 27 is a load acting on the lifting device. That is, the internal switch 27a is provided which is turned on when the pressure acting on the lift cylinder 17 exceeds the set pressure. As shown in FIG. 1, an internal switch 27a of the pressure sensor 27, a switch 28 as an operation position detecting means which is turned on when the operation position switching switching valve 16 is switched to the remote control side A, and a relay. An emergency stop circuit 30 of the electric motor 10 is constituted by connecting the relay 29 and the relay 29 in series.
b is inserted in series in the circuit for the switch 25 which is turned on and off by the remote control valve 20. In addition, the buzzer 31 as the overload display means has a relay 29.
Are connected in parallel to the emergency stop circuit 30. In FIG. 1, 32 is a battery, 33 is a main switch (key switch), and 34 is a fuse.

This embodiment is configured as described above, and therefore, in the driver's seat 2, any one of the switching valves 13, 14, 15 for lift, reach or tilt is moved from the neutral position in the drawing to the operating position (switching for lift). In the case of the valve 13, only the ascending side can be switched to the corresponding switch 2
Since 3, 24, 25 are turned on and the electric motor 10 is driven, the cylinders 17, 18, 19 are operated by the hydraulic oil sent from the hydraulic pump 9.

In this way, during the cargo handling work by the normal fork 6 operated in the driver's seat 2, the switching valve 16 for switching the operating position is switched to the driver's seat side B at the position shown in the figure, and therefore the switch 28 for detecting the operating position is operated. Since the off state is maintained, the emergency stop circuit 30 does not operate even when a load exceeding the set value set for remote control is applied.

On the other hand, when the remote control bucket 7 (which may be a pallet) is attached to the fork 6 and the remote control is used for shelf work or the like, the switching valve 16 for switching the operation position is switched and held on the remote control side A. By this switching, the control valve 12 side and the remote control valve 20 side are electrically connected and the lift cylinder 1
7, the switch 28 for operating position detection is turned on at the same time. When the remote control device 5 is operated in this state, that is, when the remote control valve 20 is switched to the rising side, the switch 25 corresponding to this is turned on,
Since the electric motor 10 is driven by the lift cylinder,
The lift cylinder 17 is lifted by the hydraulic oil sent from the hydraulic pump 9.

At this time, the load of the lifting device, that is, the lift cylinder 17
When the hydraulic pressure acting on the pressure exceeds the set pressure, the pressure sensor 2
The internal switch 27a of No. 7 is turned on, the relay 29 is energized, and its normally closed contact 29b is turned off.
0 is stopped and the lifting operation of the lift cylinder 17 is stopped. At the same time, the buzzer 31 is activated to notify the operator of the overload and call attention. In addition, during picking work for loading luggage on a shelf into the remote control bucket 7 (or pallet) with the lifting device stopped at the raised position, the electric motor 10 should be started if the loading load exceeds the allowable load. At the same time as disabling, the buzzer 31 operates to display the overload.

In this embodiment, the pressure sensor 27 is used as the load sensor.
However, the present invention is not limited to this. Further, as the buzzer 31 as the display means, it is possible to use other things such as a lamp.

(Effect of the Invention) As described in detail above, according to the present invention, when the operator rides on the remote control bucket or pallet mounted on the fork and moves freely, the remote control is performed in the overloaded state. Since the cargo handling work can be prevented and work safety can be ensured, and because the safety device of the present invention operates only when the remote control is used, the driver's seat with a larger allowable load than the remote control It is practical because there is no influence on the normal work by the operation in.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of the present invention, FIG. 2 is the same hydraulic circuit diagram, FIG. 3 is a schematic side view showing a general reach type forklift equipped with a remote control device, and FIG. 4 is a remote control. It is a perspective view showing a device mounting mode. DESCRIPTION OF SYMBOLS 1 ... Car body 2 ... Driver seat 5 ... Remote control device 7 ... Remote control bucket 9 ... Hydraulic pump 10 ... Electric motor 16 ... Switching valve for operating position switching 17 ... Lift cylinder 20 ... Remote control valve 27 ... Pressure sensor 28 ... Operating position detecting Switch 30 ... Emergency stop circuit 31 ... Buzzer

Claims (1)

[Scope of utility model registration request] 1. A forklift having a driver's seat on the vehicle body side, a remote control device for operating a lift cylinder on the elevating device side, and a motor for driving a cargo handling hydraulic pump, and a load acting on the elevating device. A load sensor that detects and outputs a signal when the set load is exceeded, a means for detecting switching of a switching valve for switching the operating position provided in the hydraulic circuit of the cargo handling actuator to the remote control side, and the means A forklift safety device with a remote control device, comprising means for stopping the motor when a signal is output from the load sensor in a state where switching to the remote control is detected.