JPH04365798A - Cargo handling mechanism - Google Patents

Abstract

PURPOSE:To provide a cargo handling operating mechanism excellent in controllability with no misoperation such as simultaneously performing lift operation and front/rear tilt operation in a forklift truck. CONSTITUTION:An oil control valve 1 used for lift or front/rear tilt operation and an operating lever 11 for controlling this valve are provided. A solenoid valve 2 for switching an oil path to a lift cylinder 91 or tilt cylinder 92 is provided separately from the oil control valve 1. A changeover switch 3 for switching action like the solenoid valve 2 is provided in the operating lever 11.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cargo handling operation mechanism for a forklift truck or the like that uses hydraulic pressure to perform cargo handling operations.

0002

2. Description of the Related Art As shown in FIG. 4, a forklift truck 8 has a mast 85 at the front of the vehicle body that can be tilted forward and backward, and a fork 86 that moves up and down along the mast 85.
have. The forward and backward tilting operation of the mast 85 is performed by supplying hydraulic oil to the tilt cylinder 92. Further, the lifting and lowering operation of the fork 86 is performed by supplying hydraulic oil to the lift cylinder 91. The hydraulic oil 90 is supplied via a hydraulic pump 97 and an oil control valve 93, as shown in FIG. That is,
When lifting or lowering the lift cylinder 91, the oil control valve 93 is operated using the lifting lever 81, and when tilting the tilt cylinder 92 back and forth, the lever 82 is used. This allows the fork 86 to be raised or lowered to any desired height, and the mast 85 to be tilted forward or backward at any desired angle. In addition, in FIG. 5, symbols 811 and 821
95 and 96 are the link mechanisms connecting the operating levers 81 and 82 and the oil control valve 93, and 98 are the oil passages.
is the return pipe.

0003

[Problem to be Solved] However, in the conventional cargo handling operation mechanism described above, the elevating/lowering operating lever 81 and the forward/backward tilting operating lever 82 may be operated at the same time. Such simultaneous operation involves a change in the center of gravity of the forklift truck and a change in the center of gravity of the load at the same time, so both levers must be operated in a well-balanced manner, which requires skill. Such problems are
This is common to industrial vehicles that perform cargo handling operations using hydraulic pressure, such as forklift trucks and excavator rotors. In view of these problems, the present invention aims to provide a cargo handling mechanism for an industrial vehicle that can safely perform lifting and lowering operations and tilting operations forward and backward without malfunction, and has excellent operability.

0004

[Means for solving the problems] In order to solve the above problems, the present invention provides an oil control valve for controlling the operation of the cylinders in a hydraulically operated industrial vehicle having a plurality of cylinders for carrying out cargo handling operations. , an operating lever for operating the oil control valve, and a solenoid valve connected to the oil control valve via a connecting pipe and for selecting one of the plurality of cylinders and switching the oil path. In addition, the operating lever is provided with a changeover switch for operating the solenoid valve, and the operation of one of the cylinders is selected by switching the changeover switch, and the cargo handling operation is performed by the operation lever. Adopted.

The most noteworthy feature of the present invention is that it is provided with an oil control valve that determines the flow direction of oil for cargo handling operations, and a solenoid valve that selects the cylinder to be used for cargo handling operations. The operation lever is provided with a changeover switch for operating the solenoid valve. Further, the present invention can be applied to industrial vehicles such as forklift trucks and shovel loaders.

[0006]

[Operations and Effects] In the cargo handling operation mechanism of the present invention, first, one of the cargo handling operations to be performed is selected. For example, when the present invention is applied to a general forklift truck, the changeover switch provided on the operating lever is left OFF when operating the lift cylinder. In this state, the oil passage is connected so that hydraulic oil is supplied from the oil control valve to the lift cylinder via the solenoid valve. Then, the oil control valve is operated using the operating lever to raise or lower the lift cylinder.

Next, when operating the tilt cylinder, the changeover switch on the operating lever is turned on. This activates the solenoid valve and connects the oil passage so that hydraulic oil is supplied to the tilt cylinder. Therefore,
Operate the oil control valve using the operating lever to tilt the tilt cylinder forward or backward. As described above, according to the present invention, the solenoid valve selects one of the plurality of cylinders by switching the changeover switch, so that the plurality of cylinders are not operated at the same time.

[0008] Furthermore, since the operation of the cargo handling cylinder is carried out by the operating lever as in the past, cargo handling operations are easy.
The changeover switch for the cargo handling cylinder is attached to the operating lever, making it easy to switch. therefore,
According to the present invention, it is possible to provide a cargo handling operation mechanism for an industrial vehicle that can safely perform lifting and lowering operations and tilting operations forward and backward without malfunction, and has excellent operability.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A cargo handling operation mechanism according to an embodiment of the present invention will be explained with reference to FIGS. 1 to 3. In this example, the present invention is applied to a forklift truck. As shown in FIG. 1, the cargo handling operation mechanism in the forklift truck includes a lift cylinder 91 for lifting and lowering, a tilt cylinder 92 for tilting forward and backward, and an oil control valve 1 used for the above-mentioned lifting and lowering operations or tilting forward and backward operations. It has an operating lever 11 for this purpose. Further, a solenoid valve 2 for switching oil passages 951, 952 or 961, 962 to the lift cylinder 91 or the tilt cylinder 92 is provided adjacent to the oil control valve 1. Connecting pipes 14, 15, 17, and 18 are interposed between the two. Further, the operating lever 11 is provided with a changeover switch 3 for operating the solenoid valve 2.

[0010] The changeover switch 3 and the solenoid valve 2
An electric circuit 30 is provided between the switch 3 and the switch 3 to transmit ON/OFF switching signals for the changeover switch 3. In addition,
A hydraulic pump 95 for supplying hydraulic oil, a return pipe 98, and a bypass 981 are connected to the oil control valve 1. Further, the operating lever 11 is connected to the oil control valve 1 via a lever mechanism 12, as shown in FIGS. 2 and 3. Further, the lever mechanism 12 is pivotally attached to a bracket 801 of the chassis 80 so as to be rotatable. The grip 110 of the operating lever 11 has the changeover switch 3 provided therein.

Next, the functions and effects will be explained. In operating the cargo handling operation mechanism, first, one of the lift cylinder 91 and the tilt cylinder 92 is selected to be operated. Therefore, first, the case where the lift cylinder 91 is moved up and down will be explained. In the case of operation of the lift cylinder 91, the solenoid valve 2 has ports L and M connected to the lift cylinder 9, as shown in FIG.
It is connected to oil passages 951 and 952 to 1. At this time, the changeover switch 3 of the operating lever 11 is in the OFF state. Therefore, when lifting the lift cylinder 91, the operating lever 11 is operated to connect ports A and B of the oil control valve 1 to the connecting pipes 14 and 15.

[0012] As a result, the hydraulic oil sent from the hydraulic pump 95 is transferred to ports A and A of the oil control valve 1.
The oil passes through the connecting pipe 14, the port L of the solenoid valve 2, and the oil passage 951, and is supplied to the lower cylinder of the lift cylinder 91. Therefore, the lift cylinder 91 operates upward. At this time, the hydraulic oil in the upper cylinder of the lift cylinder 91 flows through the oil passage 952, the port M of the solenoid valve 2,
It returns to the oil tank 901 via the connection pipe 15, port B of the oil control valve 1, and return pipe 98.

On the other hand, in order to lower the lift cylinder 91, the solenoid valve 2 is left in the same position and the operating lever 3 of the oil control valve 1 is operated so that the port C is connected to the oil pump 95 side and the connecting pipe 15 side. , connect port D with pipe 14 and return pipe 98
Connect to the side. As a result, the lift cylinder 91 is lowered. After the lift cylinder 91 has finished raising and lowering, the oil control valve 1 is returned to the neutral position as shown in FIG.

Next, when operating the tilt cylinder 92, first press the changeover switch 3 to turn it on. As a result, the solenoid valve 2
Electromagnet 21 is energized, and its ports J and K are connected to connecting pipes 17 and 18 and oil passages 961 and 962. Therefore, when tilting the tilt cylinder 92 forward,
The oil control valve 1 is operated by the operating lever 11, and its port A is connected to the connecting pipe 17 and its port B is connected to the connecting pipe 18. As a result, the hydraulic pump 9
The hydraulic oil No. 5 is supplied to the rear cylinder of the tilt cylinder 92 through port A, the connecting pipe 17, port J of the solenoid valve 2, and oil passage 961. The hydraulic oil in the front cylinder passes through the oil passage 962, port K, connection pipe 18, port B, and return pipe 98, and then passes through the oil tank 9.
Return to 01. Therefore, the tilt cylinder 92 is tilted forward.

On the other hand, when tilting the tilt cylinder 92 backward, the solenoid valve 2 remains in the same position and only the oil control valve 1 is operated to connect the port C to the connecting pipe 18 and the port D to the connecting pipe 17.
Connect to. As a result, hydraulic oil is supplied to the front cylinder of the tilt cylinder 92, and the tilt cylinder 92 is tilted backward. After the tilt cylinder 92 is operated, the oil control valve 1 is returned to the neutral position as shown in FIG. Note that the electric circuit 30 switches the changeover switch 3 while the operating lever 11 is being operated, that is, when the oil control valve 1 is not in the neutral position.
The switch is configured to disable ON/OFF switching of the switch.

As described above, the cargo handling operation mechanism of this embodiment has one operation lever 11, and either the lift cylinder 91 or the tilt cylinder 92 is selected by the changeover switch 3 and the solenoid valve 2. Therefore, there is no possibility of a malfunction in which both cylinders are operated at the same time. Further, since the lifting/lowering and forward/backward tilting operations are performed using the operating lever 11 and the oil control valve 1 as in the conventional case, the operations are easy. Further, since the changeover switch 3 is attached to the operation lever 11, the changeover operation thereof is also easy. Although an example in which the present invention is applied to a forklift truck is shown here, it is also possible to apply the present invention to a shovel loader by replacing the tilt cylinder with a dump cylinder.

[Brief explanation of drawings]

FIG. 1 is an overall explanatory diagram of a cargo handling operation mechanism according to an embodiment.

FIG. 2 is a front view of the operating lever of the embodiment.

FIG. 3 is a side view of the operating lever of the embodiment.

FIG. 4 is a side view of a conventional forklift truck.

FIG. 5 is an explanatory diagram of a cargo handling operation mechanism in a conventional example.

[Explanation of symbols]

1. ．． ．． oil control valve, 11. ．． ．． control lever, 2. ．． ．． solenoid valve, 3. ．． ．． changeover switch, 91. ．． ．． lift cylinder, 92. ．． ．． tilt cylinder,

Claims (1)

[Claims] Claim 1: A hydraulically operated industrial vehicle having a plurality of cylinders for carrying out cargo handling work, comprising an oil control valve for controlling the operation of the cylinders;
An operating lever for operating the oil control valve and a solenoid valve connected to the oil control valve via a connecting pipe for selecting one of the plurality of cylinders and switching the oil path are provided. Further, the operating lever is provided with a changeover switch for operating the solenoid valve, and the cylinder to be operated is selected by switching the changeover switch, and the cargo handling operation is performed by the operation lever. cargo handling operation mechanism.