JP7107151B2 - Hydraulic drives for industrial vehicles - Google Patents

Description

The present invention relates to a hydraulic drive system for industrial vehicles.

As a hydraulic drive system for industrial vehicles, for example, as described in Patent Document 1, a system mounted on a forklift equipped with a container spreader having a twist lock pin that is fitted into a corner fitting of a container is known. . The hydraulic drive device described in Patent Document 1 includes a twist lock cylinder that rotates a twist lock pin, a lift cylinder that raises and lowers a container spreader, a first solenoid valve that enables the twist lock cylinder to be operated by a twist lock lever, a lift a second solenoid valve that enables the lift cylinder to be operated by a lever; an insertion detection sensor that is provided on the container spreader and detects that the twist lock pin is completely inserted into the corner fitting of the container; and is provided on the container spreader, A lock detection sensor that detects that the twist lock pin is completely locked or unlocked to the corner fitting of the container, and a first fixing device that disables operation of the twist lock lever when the twist lock lever is not operated. and a second locking device that disables operation of the lift lever when the lift lever is not operated. When the detection signal of the insertion detection sensor is sent, the first solenoid valve is opened and the first fixing device is operated to make the twist lock lever operable. When the detection signal of the lock detection sensor is sent, the second electromagnetic valve is opened and the second fixing device is operated to enable the lift lever to be operated.

JP-A-11-349297

By the way, in the above conventional technology, the twist lock pin (holding portion) is locked (locked state) or not locked (unlocked state) to the corner fitting of the container by the twist lock lever (operating tool). When the above operation is performed, for example, by disabling the upward operation of the lift lever by the second fixing device, the upward movement of the container spreader (hanging tool) can be stopped. In this case, if the time from when the twist lock lever is operated to when the container spreader stops rising becomes longer, the distance at which the container spreader stops rising becomes longer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic drive system for an industrial vehicle that can shorten the time from the operation of an operating tool for rotating a holding part to the stoppage of the operation of a lifting tool.

According to one aspect of the present invention, there is provided a hydraulic drive apparatus for an industrial vehicle equipped with a plurality of holding portions for holding loads and a hoisting tool for hoisting the load. a hydraulic actuator, a second hydraulic actuator that rotates the holding portion by supplying and discharging hydraulic oil, a first operating tool for vertically moving the sling, and a second operating tool for rotating the holding portion; A hydraulic pump that supplies hydraulic fluid to the first hydraulic actuator and the second hydraulic actuator, and a hydraulic pump that is arranged between the hydraulic pump and the first hydraulic actuator to control the flow of the hydraulic fluid according to the operating state of the first operating tool. The first control valve, the second control valve arranged between the hydraulic pump and the second hydraulic actuator for controlling the flow of hydraulic oil in accordance with the operating state of the second operating tool, and the lifting tool move upward. a stop drive unit that forcibly stops the holding unit, a lock operation detection unit that detects whether or not a lock operation for putting the holding unit into a locked state has been performed by the second operation tool, and a holding unit that is locked by the second operation tool. An unlocking operation detection unit for detecting whether or not an unlocking operation has been performed to obtain an unlocked state, is connected to the lock operation detection unit and the unlocking operation detection unit, and is connected to the lock operation or unlock operation of the second operation tool. is connected to the operation detection unit for detecting whether or not is performed, the stop drive unit and the operation detection unit, and when the operation detection unit detects that the lock operation or unlock operation of the second operation tool has been performed, and a control signal output section for outputting a control signal to the stop drive section so as to stop the lifting device from moving upward.

In such a hydraulic drive system for an industrial vehicle, when the operation detection unit detects that the lock operation or unlock operation of the second operation tool has been performed while the lifting tool is moving upward, A control signal is output from the control signal output section to the stop drive section so as to stop the upward movement of the sling. Then, the upward movement of the sling is forcibly stopped by the stop driving section. As a result, the time from the operation of the second operating tool to the stop of the operation of the lifting tool is shortened.

The operation detection unit is connected to the lock operation detection unit, is connected to the first detection electric component for detecting whether or not the lock operation of the second operation tool is performed, and is connected to the unlock operation detection unit, and is connected to the second operation tool. a second detection electric component for detecting whether or not an unlocking operation has been performed; the control signal output unit is connected to the stop drive unit and the first detection electric component; 2 When it is detected that the locking operation of the operating tool has been performed, the first output electric component for outputting a control signal to the stop drive section is connected to the stop drive section and the second detection electric component, and the second A second output electric component that outputs a control signal to the stop drive unit when the detection electric component detects that the second operation tool has been unlocked. In such a configuration, when the first electric component for detection detects that the locking operation of the second operation tool has been performed, the first electric component for output outputs a control signal to the stop driving section, and the second When the second detection electric component detects that the operation tool has been unlocked, the second output electric component outputs a control signal to the stop drive section. Therefore, the time from the lock operation of the second operating tool until the operation of the hoisting tool is stopped is shortened, and the time from the unlocking operation of the second operating tool until the operation of the hoisting tool is stopped is shortened. time is reduced.

The first detection electrical component and the second detection electrical component may be relays that open when energized, and the first output electrical component and the second output electrical component may be relays that close when energized. . In this case, the operation detection section and the control signal output section can be realized at low cost.

The first control valve includes a first pilot operation part provided on the side of the position allowing the lifting tool to move upward, and a second pilot operating part provided on the side of the position allowing the lifting tool to move downward. The stop drive unit is an electromagnetic unload valve connected to the first pilot operation unit, the unload valve has a solenoid operation unit connected to the control signal output unit, Application of the pilot pressure to the first pilot operation portion may be cut off when the control signal is input to the solenoid operation portion. In such a configuration, when a control signal is output from the control signal output section to the solenoid operation section of the unload valve, application of the pilot pressure to the first pilot operation section of the first control valve is cut off. Therefore, the first control valve is switched to the neutral position, and the supply of hydraulic oil from the hydraulic pump to the first hydraulic actuator is cut off. Therefore, the sling is prevented from moving upward.

The stop drive may be a solenoid that locks the first manipulator so that the first manipulator cannot be operated. With such a configuration, when the control signal is output from the control signal output section to the solenoid, the first manipulator is disabled when the first manipulator is not operated. is kept locked. Therefore, the sling is prevented from moving upward.

ADVANTAGE OF THE INVENTION According to this invention, the time from performing operation of the operating tool for rotating a holding|maintenance part to stopping the operation|movement of a lifting tool can be shortened.

1 is a perspective view showing the appearance of a forklift equipped with a container spreader as an industrial vehicle equipped with a hydraulic drive system according to an embodiment of the present invention; FIG. 1 is a hydraulic circuit diagram of a hydraulic drive system according to an embodiment of the present invention; FIG. FIG. 2 is a configuration diagram of a control system of the hydraulic drive device shown in FIG. 1; It is a figure which shows the positional relationship of a twist lock pin, a lock-on limit switch, and a lock-off limit switch.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and overlapping descriptions are omitted.

FIG. 1 is a perspective view showing the appearance of a forklift equipped with a container spreader as an industrial vehicle equipped with a hydraulic drive system according to an embodiment of the present invention. In FIG. 1, a forklift 1, which is an industrial vehicle, includes a vehicle body 2, four wheels 3 arranged on the front, back, left and right of the vehicle body 2, a mast 4 erected at the front end of the vehicle body 2, and a and a container spreader 5 attached so as to be able to move up and down.

The container spreader 5 is a lifting tool for lifting the container C which is cargo. The container spreader 5 has a plurality of (here, two) twist lock pins 6 (holding portions) that fit with the corner fittings of the container C and hold the container C. As shown in FIG. The twist lock pins 6 are rotatably provided at both left and right ends of the container spreader 5 .

FIG. 2 is a hydraulic circuit diagram of a hydraulic drive system according to one embodiment of the present invention. 2, the hydraulic drive device 10 of this embodiment includes two lift cylinders 11, two tilt cylinders 12, two twist lock cylinders 13, a lift lever 14, a tilt lever 15, and a twist lock lever 16. (see FIG. 3), hydraulic pumps 17 to 19, a control valve unit 20, a lift pilot valve 21, a tilt pilot valve 22, an unload valve 23, and a lever lock solenoid 24.

The lift cylinder 11 is a hydraulic cylinder that raises and lowers the container spreader 5 by supplying and discharging hydraulic oil. The tilt cylinder 12 is a hydraulic cylinder that tilts the container spreader 5 by supplying and discharging hydraulic oil. That is, the lift cylinder 11 and the tilt cylinder 12 are hydraulic cylinders (first hydraulic actuators) that move the container spreader 5 vertically and longitudinally. The twist lock cylinder 13 is a hydraulic cylinder (second hydraulic actuator) that rotates the twist lock pin 6 via a link (not shown) by supplying and discharging working oil. The twist lock cylinder 13 rotates the twist lock pin 6 between the unlock position and the lock position.

The lift lever 14 is an operation lever for raising and lowering the container spreader 5 . The tilt lever 15 is an operation lever for tilting the container spreader 5 . In other words, the lift lever 14 and the tilt lever 15 are operation levers (first operation tools) for moving the container spreader 5 vertically and longitudinally. The twist lock lever 16 is an operation lever (second operation tool) for rotating the twist lock pin 6 . The lift lever 14 , tilt lever 15 and twist lock lever 16 are provided on the driver's seat 7 mounted on the vehicle body 2 .

The hydraulic pumps 17 to 19 suck hydraulic oil from the tank 25 and discharge it. Relief valves 26, 27 are arranged between the discharge ports of the hydraulic pumps 17, 18 and the tank 25, respectively.

The control valve unit 20 includes a lift control valve 28 arranged between the discharge port of the hydraulic pump 17 and each lift cylinder 11 , and a tilt control valve 28 arranged between the discharge port of the hydraulic pump 18 and each tilt cylinder 12 . and a twistlock control valve 30 positioned between the outlet of the hydraulic pump 17 and each twistlock cylinder 13 .

The lift control valve 28 is a first control valve that controls the flow of hydraulic oil according to the operating state (operating direction and operating amount) of the lift lever 14 . The lift control valve 28 has a neutral position 28a (shown) that blocks the flow of hydraulic fluid between the hydraulic pump 17 and tank 25 and the lift cylinder 11, and an operating position 28a (shown) from the hydraulic pump 17 to the bottom chamber 11a of the lift cylinder 11. It has a raised position 28 b that allows oil to flow and a lowered position 28 c that allows hydraulic oil to flow from the bottom chamber 11 a of the lift cylinder 11 to the tank 25 .

The raised position 28b is a position that allows the container spreader 5 to rise. That is, the raised position 28b is a position that allows the container spreader 5 to move upward. The lowered position 28c is a position that allows the container spreader 5 to descend. A pilot operating portion 31 (first pilot operating portion) is provided on the side of the lift control valve 28 at the raised position 28b. A pilot operating portion 32 (second pilot operating portion) is provided on the side of the lowered position 28c of the lift control valve 28 .

The tilt control valve 29 is a first control valve that controls the flow of hydraulic oil according to the operation state (operation direction and operation amount) of the tilt lever 15 . The tilt control valve 29 has a neutral position 29a (shown) that blocks the flow of hydraulic fluid between the hydraulic pump 18 and tank 25 and the tilt cylinder 12, and an operating position 29a (shown) from the hydraulic pump 18 to the rod chamber 12b of the tilt cylinder 12. A rearward tilt position 29b that allows the flow of hydraulic oil from the bottom chamber 12a of the tilt cylinder 12 to the tank 25, and the flow of hydraulic oil from the hydraulic pump 18 to the bottom chamber 12a of the tilt cylinder 12. and a forward tilt position 29c that allows hydraulic oil to flow from the rod chamber 12b of the tilt cylinder 12 to the tank 25.

The rearward tilting position 29b is a position that allows the container spreader 5 to tilt backward. That is, the rearward tilting position 29b is a position that allows the container spreader 5 to move upward. The forward tilting position 29c is a position that allows the container spreader 5 to tilt forward. A pilot operating portion 33 is provided on the rearward tilting position 29b side of the tilt control valve 29 . A pilot operating portion 34 is provided on the forward tilting position 29c side of the tilt control valve 29 .

Twist-lock control valve 30 has a neutral position 30a (shown) that blocks the flow of hydraulic fluid between hydraulic pump 17 and tank 25 and twist-lock cylinder 13, and a bottom chamber 13a of twist-lock cylinder 13 from hydraulic pump 17. and a lock position 30b that allows hydraulic fluid to flow from the rod chamber 13b of the twist lock cylinder 13 to the tank 25, and from the hydraulic pump 17 to the rod chamber 13b of the twist lock cylinder 13 and an unlock position 30c that allows hydraulic fluid to flow from the bottom chamber 13a of the twist lock cylinder 13 to the tank 25. As shown in FIG.

The lock position 30b is a position that allows the twist lock pin 6 to be locked (locked on). The unlocked position 30c is a position that allows the twist lock pin 6 to be unlocked (locked off). A pilot operating portion 35 is provided on the lock position 30b side of the twist lock control valve 30 . A pilot operating portion 36 is provided on the unlock position 30c side of the twist lock control valve 30 .

Electromagnetic switching valves 37 and 38 are arranged between the hydraulic pump 19 and the tank 25 and the pilot operating portions 35 and 36, respectively. The electromagnetic switching valves 37 and 38 are normally closed electromagnetic valves. The twist lock control valve 30 and electromagnetic switching valves 37 and 38 are second control valves that control the flow of hydraulic oil in accordance with the operating state (operating direction and operating amount) of the twist lock lever 16 .

The electromagnetic switching valve 37 shuts off the hydraulic pump 19 and the pilot operation part 35 and communicates the hydraulic pump 19 and the pilot operation part 35 with a closed position 37a (illustrated) that allows communication between the tank 25 and the pilot operation part 35. It also has an open position 37b for disconnecting the tank 25 and the pilot operating portion 35. As shown in FIG. A lock-on solenoid 39, which is a solenoid operating portion, is provided on the open position 37b side of the electromagnetic switching valve 37. As shown in FIG. When the lock-on solenoid 39 is OFF (current does not flow), the electromagnetic switching valve 37 is in the closed position 37a, and when the lock-on solenoid 39 is ON (current flowing), the electromagnetic switching valve 37 It becomes the open position 37b.

The electromagnetic switching valve 38 shuts off the hydraulic pump 19 and the pilot operation part 36, and communicates the hydraulic pump 19 and the pilot operation part 36 with a closed position 38a (illustrated) that allows communication between the tank 25 and the pilot operation part 36. It also has an open position 38b that disconnects the tank 25 and the pilot operating portion 36. As shown in FIG. A lock-off solenoid 40, which is a solenoid operation portion, is provided on the open position 38b side of the electromagnetic switching valve 38. As shown in FIG. When the lock-off solenoid 40 is OFF (current does not flow), the electromagnetic switching valve 38 is in the closed position 38a, and when the lock-off solenoid 40 is ON (current flowing), the electromagnetic switching valve 38 The open position 38b is reached.

The lift pilot valve 21 applies a pilot pressure corresponding to the amount of operation of the lift lever 14 to the pilot operating portion 31 of the lift control valve 28 when the lift lever 14 is operated to raise the container spreader 5 . The lift pilot valve 21 applies pilot pressure corresponding to the amount of operation of the lift lever 14 to the pilot operating portion 32 of the lift control valve 28 when the lift lever 14 is operated to lower the container spreader 5 .

The tilt pilot valve 22 applies a pilot pressure corresponding to the operation amount of the tilt lever 15 to the pilot operation portion 33 of the tilt control valve 29 when the tilt lever 15 is operated to tilt the container spreader 5 backward. . The tilt pilot valve 22 applies a pilot pressure corresponding to the amount of operation of the tilt lever 15 to the pilot operation portion 34 of the tilt control valve 29 when the tilt lever 15 is operated to tilt the container spreader 5 forward. .

The unload valve 23 is arranged between the lift pilot valve 21 and the pilot operating portion 31 of the lift control valve 28 . The unload valve 23 is a normally closed solenoid valve. The unload valve 23 cuts off the lift pilot valve 21 and the pilot operation part 31, and has a closed position 23a (illustrated) in which the tank 25 and the pilot operation part 31 are communicated. , and has an open position 23b that disconnects the tank 25 and the pilot operating portion 31. As shown in FIG.

An unload solenoid 41, which is a solenoid operation portion, is provided on the open position 23b side of the unload valve 23. As shown in FIG. When the unload solenoid 41 is in the OFF state (state in which current does not flow), the unload valve 23 is in the closed position 23a. It becomes the open position 23b. The unload valve 23 is a stop drive unit that forcibly stops the container spreader 5 from rising.

The lever lock solenoid 24 is a solenoid that mechanically locks the lift lever 14 so that the lift lever 14 cannot be operated. When the lever lock solenoid 24 is in the OFF state (no current flow), the lift lever 14 is mechanically locked. lock is released. The lever lock solenoid 24 is a stop drive unit that forcibly stops the container spreader 5 from rising.

FIG. 3 is a control system configuration diagram of the hydraulic drive device 10. As shown in FIG. 3, the hydraulic drive device 10 includes a lock-on lever switch 50, a lock-off lever switch 51, a lock-on limit switch 53, a lock-off limit switch 54, and an electrical component unit 55. As shown in FIG.

The lock-on lever switch 50 detects whether or not the twist lock lever 16 has been operated to lock the twist lock pin 6 (hereinafter referred to as lock operation of the twist lock lever 16). The lock-on lever switch 50 is connected to the lock-on solenoid 39 of the electromagnetic switching valve 37 . The lock-on lever switch 50 outputs an OFF signal when the twist lock lever 16 is not locked, and outputs an ON signal when the twist lock lever 16 is locked.

The lock-off lever switch 51 detects whether or not the twist lock lever 16 has been operated to unlock the twist lock pin 6 (hereinafter referred to as the unlock operation of the twist lock lever 16). The lock-off lever switch 51 is connected to the lock-off solenoid 40 of the electromagnetic switching valve 38 . The lock-off lever switch 51 outputs an OFF signal when the twist lock lever 16 is not unlocked, and outputs an ON signal when the twist lock lever 16 is unlocked.

The lock-on lever switch 50 constitutes a lock operation detector that detects whether or not the twist lock lever 16 has been locked. The lock-off lever switch 51 constitutes an unlock operation detection section that detects whether or not the twist lock lever 16 has been unlocked.

A lock-on limit switch 53 and a lock-off limit switch 54 are arranged inside the container spreader 5 . The twist lock pin 6 is provided with a detection projection 6a as shown in FIG.

The lock-on limit switch 53 detects whether or not the twist lock pin 6 is in the locked state by detecting the detection projection 6a. The lock-on limit switch 53 outputs an OFF signal when the twist lock pin 6 is not locked, and outputs an ON signal when the twist lock pin 6 is locked.

The lock-off limit switch 54 detects whether or not the twist lock pin 6 is in the unlocked state by detecting the detection projection 6a. The lock-off limit switch 54 outputs an OFF signal when the twist lock pin 6 is not unlocked, and outputs an ON signal when the twist lock pin 6 is unlocked.

The electrical component unit 55 has a lock-on relay 56, a lock-off relay 57, a lock-on reset relay 58, a lock-off reset relay 59, a lock-on timer relay 60, and a lock-off timer relay 61. .

The lock-on relay 56 is a relay that opens when energized. When the lock-on timer relay 60 outputs the OFF signal, the lock-on relay 56 is closed without being energized, and therefore outputs the ON signal. When an ON signal is output from the lock-on limit switch 53 and an ON signal is output from the lock-on timer relay 60 via the lock-on reset relay 58, the lock-on relay 56 is energized and opened. Therefore, an OFF signal is output.

The lock-off relay 57 is a relay that opens when energized. When the lock-off timer relay 61 outputs an OFF signal, the lock-off relay 57 is closed without being energized, and outputs an ON signal. When an ON signal is output from the lock-off limit switch 54 and an ON signal is output from the lock-off timer relay 61 via the lock-off reset relay 59, the lock-off relay 57 is energized and opened. Therefore, an OFF signal is output.

A lock-on reset relay 58 is connected to the lock-off lever switch 51 . The lock-on reset relay 58 is a relay that opens when energized. When the lock-off lever switch 51 outputs the OFF signal, the lock-on reset relay 58 is closed without being energized, and outputs the ON signal. When the unlocking operation of the twist lock lever 16 is performed and the lock-off lever switch 51 outputs an ON signal, the lock-on reset relay 58 is energized and becomes an open state. to output The lock-on reset relay 58 constitutes a second detection electric component (operation detection section) that detects whether or not the twist lock lever 16 has been unlocked.

A lock-off reset relay 59 is connected to the lock-on lever switch 50 . The lock-off reset relay 59 is a relay that opens when energized. When the lock-off reset relay 59 outputs an OFF signal from the lock-on lever switch 50, the lock-off reset relay 59 is closed without being energized, and outputs an ON signal. The lock-off reset relay 59 is energized and becomes an open state when an ON signal is output from the lock-on lever switch 50 by the locking operation of the twist lock lever 16, and therefore an OFF signal is output as a reset signal. Output. The lock-off reset relay 59 constitutes a first detection electric component (operation detection section) that detects whether or not the twist lock lever 16 has been locked.

The lock-on timer relay 60 is connected to the lock-on limit switch 53 via the lock-on reset relay 58 and also to the unload solenoid 41 and the lever lock solenoid 24 of the unload valve 23 .

The lock-on timer relay 60 is a relay with a timer that closes when energized. When the lock-on reset relay 58 outputs an ON signal, the lock-on timer relay 60 is energized and closed, so it outputs an ON signal as a control signal to the unload solenoid 41 and the lever lock solenoid 24 . When the lock-on reset relay 58 outputs an OFF signal, the lock-on timer relay 60 is not energized and becomes an open state, so it outputs an OFF signal as a control signal to the unload solenoid 41 and the lever lock solenoid 24. .

When the lock-on reset relay 58 detects that the twist lock lever 16 has been unlocked, the lock-on timer relay 60 sends a control signal to the unload solenoid 41 to stop the upward movement of the container spreader 5 . and a second output electric component (control signal output section) that outputs to the lever lock solenoid 24 .

The lock-off timer relay 61 is connected to the lock-off limit switch 54 via the lock-off reset relay 59 and is also connected to the unload solenoid 41 of the unload valve 23 and the lever lock solenoid 24 .

The lock-off timer relay 61 is a relay with a timer that closes when energized. When the lock-off reset relay 59 outputs an ON signal, the lock-off timer relay 61 is energized and closed, so it outputs an ON signal as a control signal to the unload solenoid 41 and the lever lock solenoid 24 . When the lock-off reset relay 59 outputs an OFF signal, the lock-off timer relay 61 is not energized and becomes an open state, so it outputs an OFF signal as a control signal to the unload solenoid 41 and lever lock solenoid 24. .

When the lock-off reset relay 59 detects that the twist lock lever 16 has been locked, the lock-off timer relay 61 sends a control signal to the unload solenoid 41 and the unload solenoid 41 to stop the container spreader 5 from rising. It constitutes a first output electric component (control signal output section) that outputs to the lever lock solenoid 24 .

In the forklift 1 equipped with the hydraulic drive device 10 as described above, when the lock operation of the twist lock lever 16 is performed while the container spreader 5 is being raised, the lock-on solenoid 39 of the electromagnetic switching valve 37 is activated by the lock-on lever switch 50 . ON signal is output to . Then, the electromagnetic switching valve 37 is switched from the closed position 37a to the open position 37b, and the discharge pressure of the hydraulic pump 19 is applied to the pilot operating portion 35 of the twist lock control valve 30 as pilot pressure. Therefore, the twist lock control valve 30 is switched from the neutral position 30a to the lock position 30b, and hydraulic oil from the hydraulic pump 17 is supplied to the bottom chamber 13a of the twist lock cylinder 13. As a result, the twist lock cylinder 13 extends, the twist lock pin 6 rotates from the unlock position to the lock position via a link (not shown), and the twist lock pin 6 is locked.

At this time, since an ON signal is output from the lock-on lever switch 50 to the lock-off reset relay 59 , the lock-off reset relay 59 is energized and opened, and the lock-off reset relay 59 outputs an OFF signal to the lock-off timer relay 61 . is output. Then, the lock-on timer relay 60 is opened without being energized, and an OFF signal is output from the lock-off timer relay 61 to the unload solenoid 41 of the unload valve 23 and the lever lock solenoid 24 .

When an OFF signal is input to the unload solenoid 41 of the unload valve 23, the unload valve 23 is switched from the open position 23b to the closed position 23a, and the pilot pressure corresponding to the operation amount of the lift lever 14 is applied to the lift control valve 28. is not applied to the pilot operating portion 31, and the pressure of the pilot operating portion 31 becomes the tank pressure. Further, when an OFF signal is input to the lever lock solenoid 24, the lift lever 14 is mechanically locked by the lever lock solenoid 24 so that the lift lever 14 cannot be operated. As described above, the lift control valve 28 is switched from the raised position 28b to the neutral position 28a, and the supply of hydraulic oil from the hydraulic pump 17 to the bottom chamber 11a of the lift cylinder 11 is cut off. Therefore, since the extension operation of the lift cylinder 11 is stopped, the rising of the container spreader 5 is stopped.

On the other hand, when the twist lock lever 16 is unlocked while the container spreader 5 is ascending, an ON signal is output from the lock-off lever switch 51 to the lock-off solenoid 40 of the electromagnetic switching valve 38 . Then, the electromagnetic switching valve 38 is switched from the closed position 38a to the open position 38b, and the discharge pressure of the hydraulic pump 19 is applied to the pilot operating portion 36 of the twist lock control valve 30 as pilot pressure. Therefore, the twist lock control valve 30 is switched from the neutral position 30a to the unlocked position 30c, and hydraulic oil from the hydraulic pump 17 is supplied to the rod chamber 13b of the twist lock cylinder 13. As a result, the twist lock cylinder 13 contracts, and the twist lock pin 6 rotates from the locked position to the unlocked position via a link (not shown), and the twist lock pin 6 enters the unlocked state.

At this time, since an ON signal is output from the lock-off lever switch 51 to the lock-on reset relay 58 , the lock-on reset relay 58 is energized and opened, and the lock-on reset relay 58 outputs an OFF signal to the lock-on timer relay 60 . is output. Then, the lock-on timer relay 60 is opened without being energized, and an OFF signal is output from the lock-on timer relay 60 to the unload solenoid 41 of the unload valve 23 and the lever lock solenoid 24 . Therefore, the lift control valve 28 is switched from the raised position 28b to the neutral position 28a in the same manner as described above, and the supply of hydraulic oil from the hydraulic pump 17 to the bottom chamber 11a of the lift cylinder 11 is cut off. Therefore, since the extension operation of the lift cylinder 11 is stopped, the rising of the container spreader 5 is stopped.

As described above, in this embodiment, when the twist lock lever 16 is locked or unlocked while the container spreader 5 is being raised, the lock-on reset relay 58 or the lock-off reset relay 58 or the lock-off reset relay 59, regardless of the output signals of the lock-on limit switch 53 and the lock-off limit switch 54, the OFF signal, which is a control signal for stopping the upward movement of the container spreader 5, is sent to the lock-on timer relay 60 or the lock-on timer relay 60. Output from the off-timer relay 61 to the unload solenoid 41 of the unload valve 23 and the lever lock solenoid 24 . Then, the lifting operation of the container spreader 5 is forcibly stopped by the unload valve 23 and the lever lock solenoid 24 . This shortens the time from when the twist lock lever 16 is operated until the container spreader 5 stops rising. As a result, the lifting stop distance of the container spreader 5 is shortened.

Further, in this embodiment, when the lock-off reset relay 59 detects that the twist lock lever 16 has been locked, the lock-off timer relay 61 outputs an OFF signal to the unload solenoid 41 and the lever lock solenoid 24 . When the unlock operation of the twist lock lever 16 is detected by the lock-on reset relay 58, the lock-on timer relay 60 outputs an OFF signal to the unload solenoid 41 and the lever lock solenoid 24. . Therefore, the time from the lock operation of the twist lock lever 16 to the stop of the upward movement of the container spreader 5 is shortened, and the upward movement of the container spreader 5 is stopped from the unlock operation of the twist lock lever 16. shortens the time to

Further, in this embodiment, when an OFF signal is output from the lock-on timer relay 60 or the lock-off timer relay 61 to the unload solenoid 41 of the unload valve 23, the pilot pressure to the pilot operation portion 31 of the lift control valve 28 is grant is blocked. Therefore, the lift control valve 28 is switched from the raised position 28b to the neutral position 28a, and the supply of hydraulic oil from the hydraulic pump 17 to the lift cylinder 11 is cut off. Therefore, the upward movement of the container spreader 5 is prevented.

Further, in this embodiment, when an OFF signal is output from the lock-on timer relay 60 or the lock-off timer relay 61 to the lever lock solenoid 24, the lift lever 14 is operated when the lift lever 14 is not operated. The lift lever 14 is held locked so that it is disabled. Therefore, the upward movement of the container spreader 5 is further prevented.

In the present embodiment, relays that open when energized are used as the lock-on reset relay 58 and the lock-off reset relay 59, and relays that close when energized are used as the lock-on timer relay 60 and the lock-off timer relay 61. Since it is used, the electrical component unit 55 can be realized at low cost. The unload valve 23 is of a type that releases the stoppage of the container spreader 5 when current flows through the unload solenoid 41, and the lever lock solenoid is of a type that releases the stoppage of the container spreader 5 when current flows. 24 can be used.

In addition, this invention is not limited to the said embodiment. For example, in the above-described embodiment, the hydraulic drive system 10 includes the unload valve 23 that cuts off application of the pilot pressure to the pilot operation portion 31 of the lift control valve 28, and the lift lever 14 that disables the operation of the lift lever 14. However, the configuration is not particularly limited, and only one of the unload valve 23 and the lever lock solenoid 24 may be provided. Even in this case, the upward movement of the container spreader 5 can be prevented. In particular, when only the unload valve 23 is provided, even if the lift lever 14 is operated to raise the container spreader 5, the container spreader 5 is prevented from being raised.

Further, in the above-described embodiment, the lock-on reset relay 58 outputs an OFF signal when an ON signal is output from the lock-off lever switch 51 by unlocking operation of the twist lock lever 16, and locks the lock. The off-reset relay 59 outputs an off signal when an on signal is output from the lock-on lever switch 50 when the lock operation of the twist lock lever 16 is performed. do not have. A lock-on reset relay 58 outputs an OFF signal when an ON signal is output from the lock-on lever switch 50 by a lock operation of the twist lock lever 16, and a lock-off reset relay 59 outputs a twist lock. When the unlocking operation of the lever 16 is performed and the ON signal is output from the lock-off lever switch 51, the OFF signal may be output.

In the above embodiment, relays that open when energized are used as the lock-on reset relay 58 and lock-off reset relay 59, and relays that close when energized are used as the lock-on timer relay 60 and lock-off timer relay 61. Although used, but not limited to the form in which it is used, other types of relays may be used, or other electrical components may be used in place of the relays.

In the above-described embodiment, the upward movement of the container spreader 5 is performed both when the twist lock pin 6 is switched from the unlocked state to the locked state and when the twist lock pin 6 is switched from the locked state to the unlocked state. Although it is made to stop, it is not restricted to the form in particular. The upward movement of the container spreader 5 may be stopped only when the twist lock pin 6 is switched from the unlocked state to the locked state, or the container spreader may be stopped only when the twist lock pin 6 is switched from the locked state to the unlocked state. 5 may be stopped.

Further, in the above-described embodiment, when the twist lock lever 16 is locked or unlocked, the upward movement of the container spreader 5 is stopped. The rearward tilting operation of the container spreader 5 may be stopped when the locking operation or unlocking operation is performed. In this case, an electromagnetic unloading valve may be arranged between the tilt pilot valve 22 and the pilot operation portion 33 of the tilt control valve 29, or the tilt lever 15 may be moved so that the tilt lever 15 cannot be operated. A lever lock solenoid to lock 15 may be provided.

Further, the above embodiment is the hydraulic drive device 10 of the forklift 1 equipped with the container spreader 5 for lifting the container C, but the present invention is also applicable to forklifts equipped with attachments for lifting other loads. In addition, the present invention can also be applied to other industrial vehicles that have a plurality of holding portions for holding loads and are equipped with hoisting tools for lifting loads.

DESCRIPTION OF SYMBOLS 1... Forklift (industrial vehicle), 5... Container spreader (hanging tool), 6... Twist lock pin (holding part), 10... Hydraulic drive device, 11... Lift cylinder (first hydraulic actuator), 12... Tilt cylinder (first 1 hydraulic actuator), 13... twist lock cylinder (second hydraulic actuator), 14... lift lever (first operation tool), 15... tilt lever (first operation tool), 16... twist lock lever (second operation tool) , 17 to 19 Hydraulic pump 23 Unload valve (stop drive unit) 24 Lever lock solenoid (solenoid, stop drive unit) 28 Lift control valve (first control valve) 28b Lift position 28c ... lowered position, 29 ... tilt control valve (first control valve), 30 ... twist lock control valve (second control valve), 31 ... pilot operation section (first pilot operation section), 32 ... pilot operation section (second Pilot operation unit), 37, 38 electromagnetic switching valve (second control valve), 41 unload solenoid (solenoid operation unit), 50 lock-on lever switch (lock operation detection unit), 51 lock-off lever switch ( Unlocking operation detection unit), 58 Lock-on reset relay (second detection electric component, operation detection unit), 59 Lock-off reset relay (first detection electric component, operation detection unit), 60 Lock-on timer Relay (electric component for second output, control signal output section), 61... Lock-off timer relay (electric component for first output, control signal output section), C... Container (package).

Claims (5)

In a hydraulic drive device for an industrial vehicle, which has a plurality of holding parts for holding loads and is equipped with a lifting tool for lifting the loads,
a first hydraulic actuator that vertically moves the sling by supplying and discharging hydraulic oil;
a second hydraulic actuator that rotates the holding portion by supplying and discharging the hydraulic oil;
a first operating tool for moving the lifting tool in the vertical direction;
a second manipulator for rotating the holding part;
a hydraulic pump that supplies the hydraulic fluid to the first hydraulic actuator and the second hydraulic actuator;
a first control valve disposed between the hydraulic pump and the first hydraulic actuator, the first control valve controlling the flow of the hydraulic oil according to the operating state of the first operation tool;
a second control valve disposed between the hydraulic pump and the second hydraulic actuator, the second control valve controlling the flow of the hydraulic oil according to the operating state of the second operation tool;
Composed of electromagnetic parts, a stop driving unit for forcibly stopping the lifting device from moving upward;
a lock operation detection unit that detects whether or not a lock operation for locking the holding unit has been performed by the second operation tool;
an unlocking operation detection unit that detects whether or not an unlocking operation for bringing the holding unit into an unlocked state has been performed by the second operation tool;
connected to the lock operation detector and the unlock operation detector;and composed of relays, an operation detection unit that detects whether the lock operation or the unlock operation of the second operation tool has been performed;
It is connected to the stop drive unit and the operation detection unit, and when the operation detection unit detects that the locking operation or the unlocking operation of the second operation tool is performed, the lifting tool moves upward. and a control signal output unit for outputting a control signal to the stop drive unit to stop the hydraulic drive unit for an industrial vehicle. The operation detection unit is connected to the lock operation detection unit and includes a first detection electric component, which is a relay for detecting whether or not the lock operation of the second operation tool has been performed, and the unlock operation detection unit. a second detection electric component that is a relay that is connected and detects whether the unlocking operation of the second operation tool has been performed;
The control signal output section is connected to the stop drive section and the first electric component for detection, and when the first electric component for detection detects that the locking operation of the second operating tool has been performed, , a first output electric component for outputting a control signal for stopping the upward movement of the sling to the stop drive section; and the stop drive section and the second detection electric component connected to the When the unlocking operation of the second operating tool is detected by the second detecting electric component, a control signal is sent to the stop drive unit to stop the lifting tool from moving upward. 2. The hydraulic drive system for an industrial vehicle according to claim 1, further comprising a second output electric component for output. The first electrical component for detection and the electrical component for second detection are relays that open when energized,
3. The hydraulic drive system for an industrial vehicle according to claim 2, wherein said first electrical component for output and said electrical component for second output are relays which are closed when energized. The first control valve includes a first pilot operation part provided on a position side that allows the lifting tool to move upward, and a position side that allows the lifting tool to move downward. and a second pilot operation unit,
The electromagnetic component is an electromagnetic unload valve having a solenoid operation portion connected to the first pilot operation portion and connected to the control signal output portion ,
The unload valve has a closed position that blocks application of pilot pressure to the first pilot operation section and an open position that allows application of pilot pressure to the first pilot operation section, and 4. The open position is switched to the closed position when a control signal for stopping the upward movement of the lifting device is input to the solenoid operation portion during the upward movement of the or a hydraulic drive system for an industrial vehicle according to claim 1. 5. The hydraulic drive system for an industrial vehicle according to claim 1, wherein the electromagnetic component is a solenoid that locks the first operating tool so that the first operating tool cannot be operated.

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