KR101417045B1 - Hydraulic system for actuating forks of forklift truck with a sideshift carriage - Google Patents

Abstract

The present invention discloses a fork-operated hydraulic device for a forklift. The fork hydraulic pressure device includes a left hydraulic cylinder 40 for moving the left fork 41 to the left and right, a right hydraulic cylinder 50 for moving the right fork 51 to the left and right, And a control valve (20) for controlling the flow of hydraulic fluid supplied to the left and right hydraulic cylinders (40, 50), characterized in that only the left and right ports (B1, B2) of the left hydraulic cylinder A left fork actuating part 11 composed of two ports L1 and L2 for supplying or discharging air; A right fork actuating part 12 composed of two ports R1 and R2 for supplying or discharging hydraulic fluid only to the left and right ports A1 and A2 of the right hydraulic cylinder 50; And the left and right hydraulic cylinders (40, 50) are provided with hydraulic oil cylinders (40, 50) for supplying hydraulic oil to both left and right ports A1, A2, B1, B2 of the left and right hydraulic cylinders And a side shift operation part 13 composed of ports S1 and S2. The present invention can simplify the carriage structure by allowing two hydraulic cylinders for left and right forks and one hydraulic cylinder for side shift carriage to perform the same function with two hydraulic cylinders, I can do it.

Description

TECHNICAL FIELD [0001] The present invention relates to a fork lift truck,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fork-operated hydraulic device for a forklift, and more particularly to a fork-work hydraulic device for a forklift capable of separately operating the left and right forks and transporting them together by a side-shift carriage.

Generally, a forklift truck is used to transport a relatively heavy cargo to a desired position by a worker, and is widely used throughout the industry. A brief description of such a forklift is as follows. The vehicle body of the forklift is supported by a front drive wheel and a rear steering wheel, and a mast assembly is installed at the front. The lower end of the mast assembly is rotatably mounted on a drive shaft supporting the front drive wheel. The mast rail is provided with a vertically installed mast rail. The mast rail is vertically moved along the mast rail, Side shift carriage is mounted.

1 shows a structure in which two forks 2 and 3 are mounted on a side shift carriage 1 in a conventional forklift. In the structure shown in the figure, the two forks 2 and 3 can be independently transported laterally by two hydraulic cylinders 5 and 6, and although not shown in the drawings, the side shift carriage 1 itself There is provided a hydraulic cylinder for movement.

2 shows a hydraulic cylinder 5 for a left fork 2 and a hydraulic cylinder 6 for a right fork 3 for independently operating the left and right forks 2 and 3 shown in Fig. The main control valve device 8 is provided with a left fork actuating part 5 ', a right fork actuating part 6' and a shift carriage actuating part 5 'for controlling the hydraulic cylinder 7 for operating the side shift carriage 1, The left and right forks and the shift carriage are independently controlled by controlling the flow rate and flow of the hydraulic oil supplied by the hydraulic pump 9. [ The main control valve device is also provided with a hydraulic cylinder operating part for tilting and lifting, but the hydraulic cylinder for tilting and lifting is omitted in FIG. 2 for the sake of simplicity. Reference numeral 4 is a return filter for filtering foreign matters when the operating oil returns to the tank shown at the lower end in the drawing.

In the structure in which the two forks are provided on the conventional side shift carriage for a forklift, the three hydraulic cylinders 5, 6, 7 are provided so as to operate independently of each other, so that the forks and the side shift are individually and There is a problem in that the structure is complicated and the manufacturing cost is high because the carriage having a complicated structure must be used in order to allow simultaneous movement.

Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a forklift fork that can operate both forks and side shift carriages independently and simultaneously with only two hydraulic cylinders And to provide a hydraulic device.

In order to achieve the above object, the present invention provides a hydraulic control apparatus for an internal combustion engine, comprising a left hydraulic cylinder for moving a left fork to the left and right, a right hydraulic cylinder for moving a right fork to the left and right, A fork hydraulic actuator for a forklift comprising a control valve, comprising: a left fork actuating part comprising two ports for supplying or discharging hydraulic fluid only to left and right ports of the left hydraulic cylinder; A right fork actuating part composed of two ports for supplying or discharging hydraulic oil only to left and right ports of the right hydraulic cylinder; And a side shift actuating part including two ports for simultaneously supplying or discharging operating fluid to the left and right ports of the left and right hydraulic cylinders, the left and right hydraulic cylinders having a flow path for operating the same in the same direction. Thereby providing an operating hydraulic device.

The present invention further provides the following specific embodiments with respect to the above embodiment of the present invention.

According to an embodiment of the present invention, the left fork actuating portion, the right fork actuating portion, the side shift actuating portion include a port communicating with the first chamber of the left fork actuating hydraulic cylinder and a port communicating with the second chamber; A port communicating with the first chamber of the right fork actuating hydraulic cylinder, and a port communicating with the second chamber; Two ports respectively communicating with two lines connected to the left fork actuating part; Two ports respectively communicating with two lines connected to the right fork actuating part; And a port communicating with each of the two lines connected to the side shift operation portion.

According to an embodiment of the present invention, the ports of the left fork actuating portion, the right fork actuating portion, and the side shift actuating portion are connected to one side line, the ports are connected to the other side line, And a check valve which can be opened according to the condition is provided.

According to an embodiment of the present invention, a pilot line communicating with the port side line of the check valve and the side shift operation portion is formed, and the check valve is formed by forming a pilot line communicating with the port side line of the side shift operation portion, And when the pressure in the pilot line reaches a predetermined pressure, the check valve of the corresponding line responds and is opened to allow backward flow.

The present invention simplifies the carriage structure by providing a control valve in addition to the main control valve device to perform the same function by reducing two hydraulic cylinders for left and right forks and one hydraulic cylinder for side shift carriage to two hydraulic cylinders Thereby reducing the manufacturing cost of the forklift truck.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 schematically shows the construction of a fork hydraulic actuator for a forklift according to the present invention. The main control valve device 10 is provided with the left fork actuating portion 11, the right fork actuating portion 12, the side shift actuating portion 13, the tilting actuating portion 14 and the lifting actuating portion 15 The main control valve device 10 according to the present invention is constructed such that the hydraulic oil supplied from the hydraulic pump 30 is additionally supplied from the left fork actuating portion 11, the right fork actuating portion 12, and the side shift actuating portion 13 And is simultaneously or selectively supplied to the two hydraulic cylinders 40 and 50 via the provided control valve 20. [ In the figure, reference numeral 60 denotes a return filter, and reference numeral 61 denotes an operating oil tank.

The control valve 20 has a hydraulic circuit configuration as shown in Fig. 4 for side-shifting the two hydraulic cylinders 40, 50 independently and simultaneously to the left or the right.

The control valve 20 includes a port B1 communicating with the first chamber 42 of the hydraulic cylinder 40 for operating the left fork 41 and a port B2 communicating with the second chamber 43; A port A1 communicating with the first chamber 52 of the hydraulic cylinder 50 for operating the right fork 51 and a port A2 communicating with the second chamber 53; Two ports R1 and R2 respectively communicating with two lines connected to the left fork actuating portion 11 of the main control valve device 10; Two ports L1 and L2 respectively communicating with two lines connected to the right fork actuating portion 12; And ports S1 and S2 communicating with two lines connected to the side-shift actuating portion 13, respectively.

The ports S1, L1 and R1 of the control valve 20 are connected to one side line 80 and the ports S2, L2 and R2 are connected to the other side line 81, 81 are provided with respective check valves (CH1, CH2), (CH3, CH4) to prevent reverse flow of the operating oil.

Pilot lines P1 and P2 communicating with the check valves CH1 and CH2 and the port S1 side line 81 of the side shift actuating part are formed while the check valves CH3 and CH4 are connected with the side shift Pilot lines P3 and P4 communicating with the line 80 on the port S2 side of the operating part are formed so that when the pressure in the pilot lines P1, P2, P3 and P4 reaches a preset pressure, (CH1, CH2, CH3, CH4) are opened to allow backflow, and this backflow is allowed only in the side shift operation.

The operation of the left and right forks by the two hydraulic cylinders and the side shift operation according to the present invention will be described with reference to the circuit diagram of the control valve 20 described above.

When the hydraulic oil is supplied through the port L1 communicated with the left fork actuating portion 11 of the main control valve device during the individual operation of the left fork 41, The operating oil flows from the second chamber 43 into the first chamber 42 of the hydraulic cylinder 40 while the working oil is returned to the tank through the port B2 and the port L2 to return the piston of the hydraulic cylinder 40 4, the left fork 41 is moved to the right in Fig.

Conversely, when the hydraulic oil flows through the port L2 and returns to the tank through the port L2, the left fork 41 is moved to the left. At this time, since the reverse flow is prevented by the check valves CH2 and CH4, Operate independently.

The individual operation of the right fork 51 is likewise carried out through the port R1 of the right fork operation part 12 of the main control device and through the port A1 of the control valve 20 for the right fork operation The hydraulic fluid in the second chamber 53 is returned to the tank through the port A2 and the port R2 and the hydraulic fluid in the second hydraulic cylinder 50 As the piston moves to the right in Fig. 4, the right fork in Fig. 5 moves to the right.

Conversely, when the working oil flows through the port R2 and returns through the port R1, the piston of the hydraulic cylinder moves in the opposite direction, and the right fork is thus moved to the left in FIG. At this time, the hydraulic cylinders 50 and the right forks can be individually operated because the check valves CH1 and CH3 prevent back flow of the hydraulic oil.

The hydraulic oil supplied through the port S1 of the main control valve device is supplied to the first chamber 52 of the right fork actuating hydraulic cylinder 50 through the check valve CH3 in the line 81 And flows into the first chamber 42 of the left fork actuating hydraulic cylinder 40 through the check valve CH4.

The operating oil in the second chamber 53 of the right fork actuating hydraulic cylinder 50 and the working oil in the second chamber 43 of the left fork actuating hydraulic cylinder 40 are supplied to the ports of the control valve 20 The pressure in the pilot lines P1 and P2 connected to the check valves CH1 and CH2 is increased due to the reverse flow by the check valves CH1 and CH2 although they are discharged through the lines A2 and B2 to the line 80, When the pressure is reached, in response, the check valves CH1 and CH2 are opened and returned to the tank via port S2. At this time, the piston of the left fork actuating hydraulic cylinder 40 is moved to the right in Fig. 4 so that the fork 41 is moved to the right in Fig. 5, while the right fork actuating cylinder 50 moves to the first chamber 52 The piston is moved to the right in Fig. 4 and the right fork 51 is moved to the right side in the same direction as the left fork so that the left and right forks are simultaneously shifted to the right side.

When the hydraulic oil is supplied through the port S2 of the main control valve device, the hydraulic oil is discharged to the ports A2 and B2 through the check valves CH1 and CH2 opposite to the above, Hydraulic pressure is applied to move the left fork to the left while flowing into the second chamber 53 of the hydraulic cylinder 50 and hydraulic pressure to move the right fork to the left. The operating fluid of the first chamber 42 of the hydraulic cylinder 40 and the first chamber 52 of the hydraulic cylinder 50 is supplied to the check valves CH3 and CH4 in response to the pressure increase of the pilot lines P3 and P4, Is returned to the tank through port S2 as it opens. As a result, the two left and right forks are simultaneously shifted to the left side.

The left and right fork actuating portions 11 and 12 of the main control valve device and the ports of the side shift actuating portion 13 are controlled through the control valve 20 so that the two hydraulic cylinders 40, 50 can be selectively operated independently, as well as side shifted simultaneously.

1 is a schematic perspective view showing left and right forks of a conventional forklift mounted on a side shift carriage;

Fig. 2 is a block diagram showing a schematic configuration of a fork-operated hydraulic device of a forklift having a conventional side shift carriage; Fig.

3 is a schematic block diagram of a hydraulic system with a control valve for selectively driving two hydraulic cylinders in accordance with the present invention to drive left and right forks independently or a side shift carriage;

4 is a view of a fork mounted on a side shift carriage to illustrate the operation of selectively or simultaneously side-shifting two forks by the hydraulic device according to the present invention;

5 is a schematic hydraulic circuit diagram of a control valve according to the present invention.

Description of the Related Art [0002]

 10: main control valve device 11: left fork operation part

 12: right fork operation part 13: side shift operation part

 20: Control valve 30: Hydraulic pump

 40, 50: hydraulic cylinder 41, 51: left and right fork

 70: Side shift carriage

 L1, L2, R1, R2, S1, S2, B1, B2, A1,

 CH1, CH2, CH3, CH4: Check valve P1, P2, P3, P4: Pilot line

Claims (4)

A left hydraulic cylinder 40 for moving the left fork 41 to the left and right, a right hydraulic cylinder 50 for moving the right fork 51 to the left and right, and a right hydraulic cylinder 50 for moving the right fork 51 from the hydraulic pump 30 to the left and right hydraulic cylinders 40, And a control valve (20) for controlling the flow of hydraulic fluid supplied to the forklift, A left fork actuating part 11 composed of two ports L1 and L2 for supplying or discharging hydraulic oil only to the left and right ports B1 and B2 of the left hydraulic cylinder 40; A right fork actuating part 12 composed of two ports R1 and R2 for supplying or discharging hydraulic fluid only to the left and right ports A1 and A2 of the right hydraulic cylinder 50; And The left and right hydraulic cylinders 40 and 50 are connected to the left and right hydraulic cylinders 40 and 50 so as to supply or discharge hydraulic oil simultaneously to the left and right ports A1, A2, B1 and B2 of the left and right hydraulic cylinders 40 and 50, And a side shift operation portion (13) composed of ports (S1, S2) The left fork actuating portion 11, the right fork actuating portion 12 and the side shift actuating portion 13 are connected to a port B1 (not shown) communicating with the first chamber 42 of the hydraulic cylinder 40 for operating the left fork 41 A port B2 communicating with the second chamber 43; A port A1 communicating with the first chamber 52 of the hydraulic cylinder 50 for operating the right fork 51 and a port A2 communicating with the second chamber 53; Two ports R1 and R2 respectively communicating with two lines connected to the left fork actuating portion 11; Two ports L1 and L2 respectively communicating with two lines connected to the right fork actuating portion 12; And And a port (S1, S2) communicating with each of two lines connected to the side shift operation portion (13). delete 2. The apparatus according to claim 1, wherein the ports (S1, L1, R1) of the left fork actuating part (11), the right fork actuating part (12), and the side shift actuating part (13) The ports S2, L2 and R2 are connected to the other line 81. The two lines 80 and 81 are provided with check valves CH1 and CH2, (CH3, < / RTI > < RTI ID = 0.0 > CH4). ≪ / RTI > 4. The apparatus according to claim 3, characterized in that pilot lines (P1, P2) communicating with the check valve (CH1, CH2) and the port (S1) side line (81) of the side shift actuating part (13) The pilot lines P3 and P4 communicating with the line 80 on the side of the port S2 of the side shift actuating portion are formed in the pilot lines P1 and P2 and the pressures in the pilot lines P1 and P2, (CH1, CH2, CH3, CH4) of the corresponding line (80, 81) responds to a predetermined pressure and is opened to allow backward flow.

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