KR19990083071A - Oil pressure controller for industrial vehicles - Google Patents

Abstract

The present invention relates to an oil pressure controller for raising and lowering the fork of the forklift. The lift control valve 27 controls the fluid supply to the lift cylinder 4. The lift control valve 27 is shifted between various positions. The check valve prevents the drain of fluid from the lift cylinder 4 to lock the fork when the hydraulic pump P is not in operation. The needle valve prevents fluid from being drained from the lift cylinder 4 when the hydraulic pump P is not in operation. The actuator 14 can be operated by a human operator to quickly open the needle valve.

Description

Oil pressure controller for industrial vehicles

The present invention relates to an oil pressure controller of an industrial vehicle.

In general, industrial vehicles such as forklifts have masts and forks. The mast is supported at the front of the vehicle to incline, and the fork is supported by the mast to ascend and descend along the mast. Lift and tilt levers are provided in the cab. The lift cylinder is actuated through the lift lever to raise and lower the fork. An inclined cylinder is actuated through the inclined lever to incline the mast forward and backward.

10 shows a hydraulic circuit for driving the lift cylinder 40. The lift control valve 41 controls the lift cylinder 40. The bottom chamber 40a of the lift cylinder 40 is connected to the lift control valve 41 via the filling passage 43. The driver operates the lift control valve 41 using the lift lever. When the lift lever 42 is in the up position, the lift control valve 410 is connected to the supply passage 44 by the filling passage 43. The lift lever is in the down position. At this time, the lift control valve 410 is connected to the return passage 45 by the filling passage 43. When the lift lever 42 is in the neutral position, the lift control valve 41 is the supply passage 44 The filling passage 43 is separated from the return passage 45, and thus holds the piston roller 40b in a predetermined position.

When the piston rod 40b is lowered by the weight of the fork and the mast, the fork is lowered. Thus, when the lift lever 42 is in the down position and the bottom chamber 40a of the lift cylinder 40 is connected to an oil tank (not shown) through the supply and fill passages 44 and 43, the fork is Lower despite the condition of the hydraulic pump (not shown). Thereby, when the forklift power source is turned off and the fork is raised, if the lift lever 42 is moved down around, the fork will be lowered.

When the lift lever is in the neutral position, hydraulic oil pressure in the bottom chamber 40a of the lift cylinder 40 is applied to the lift control valve 41. As such, a large amount of pressure is applied to the lift control valve 41 having the spool, and hydraulic oil leaks along the sliding surface between the spool and the valve housing. Thus, if the lift control valve 41 is left in the neutral position while the fork is raised, the fork will gradually descend.

In order to solve this problem, a fork leaf having a lock mechanism is provided. The lock mechanism locks the fork so that the fork does not lower when the hydraulic pump P stops or the forklift 1 is not operated. 11 and 12 show such a hydraulic circuit for forklift. In the hydraulic circuit of FIG. 11, hydraulic oil from the pump P flows to the lift cylinder 40 and a power steering valve (PS valve). The hydraulic circuit comprises a check valve 46 controlled by an electromagnet valve 51 connected to a solenoid driver circuit. The hydraulic circuit shown in FIG. 12 includes a check valve 47 controlled by an electromagnet valve 47 different from that of FIG. As shown in FIGS. 11 and 12, the shank valves 46, 47 are located in the filling passage 43. In the hydraulic circuit of FIG. 11, when the pump P is operated and the pilot pressure is applied to the shank valve 46 while the pump P is operating, the shank valve 46 is opened and the hydraulic oil is bottomed. It flows from the chamber 40a to the lift control valve 41, and also flows in a reverse direction. When the pump P is not in operation, the pilot pressure is not applied to the shank valve 46 and the shank valve 46 prevents oil from flowing from the bottom chamber 40a to the lift control valve 41. Stop it. Similarly, in the hydraulic circuit of FIG. 12, when the pump P is not operated, the electromagnet valve is configured to allow the shank valve 47 to flow oil from the bottom chamber 40a to the lift control valve 41. To stop it.

In an emergency, the fork can be lowered even when the hydraulic pump P is not operated. That is, the needle valve 48 is provided to release the lock mechanism. One end of the needle valve 48 may be connected to the bottom chamber 40a of the lift cylinder 40, and the other end may be connected to the oil tank T through the return passage 45. In the hydraulic circuit shown in FIG. 11, when the needle valve 48 is opened, the hydraulic oil in the bottom chamber 40a is returned to the oil tank T through the needle valve 48. This lowers the fork gradually. In the hydraulic circuit shown in FIG. 12, when the needle valve 48 is opened, the hydraulic valve in the bottom chamber 40a returns to the oil tank T through the needle valve 48, and the shank valve 47 is opened. Therefore, the hydraulic oil in the bottom chamber 40a is returned to the oil tank T through the shank valve 47 and the lift control valve 41, and the fork is immediately lowered.

As shown in FIG. 13, the needle valve 48 includes a valve shaft 48a to separate the passage 49 from the passage 50. The position and the flow amount of the valve shaft are adjusted by the threaded portion 48b. It is necessary to loosen the threaded portion 48b to open the needle valve 48. In addition, because the needle valve 48 is located in the tool panel of the forklift, the panel must be turned off before opening the needle valve 48b, which delays the opening of the needle valve.

It is an object of the present invention to provide an oil pressure controller of an inexpensive industrial vehicle in which the lock mechanism of attachment of the industrial vehicle is easily released.

In order to achieve the above object, the present invention provides an oil pressure controller of an industrial vehicle having a carrier which is raised and lowered. The oil pressure controller is configured as follows. The cylinder raises and lowers the carrier. The pump supplies fluid to the cylinder. The lift control valve controls the fluid supply to the cylinder to drive the cylinder. The lift control valve is shifted between the first, second and third positions. The first position allows fluid to flow from the pump to the cylinder to raise the carrier. The second position allows fluid to drain from the cylinder to lower the carrier. The third position stops the fluid supply to the cylinder and prohibits the draining of fluid from the cylinder to stop the carrier. The lock device is positioned between the cylinder and the lift control valve, where the lock device prevents fluid flow from the cylinder to prevent the carrier from descending when the pump is not operating. The drain valve allows fluid to drain from the cylinder upon opening. The actuator allows the drain valve to be operated by a human operator.

Other features and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate by way of example the principles of the invention.

1 is a side view of a forklift having an oil pressure controller according to a first embodiment;

2 is a schematic cross-sectional view of the oil pressure controller of FIG. 1.

3 is a schematic cross-sectional view of an oil pressure controller according to a second embodiment of the present invention.

4 is a schematic cross-sectional view of an oil pressure controller according to a third embodiment of the present invention.

5A to 5D show a partially enlarged view of the valve opening of the oil pressure controller of FIG. 4.

6 is a graph showing the relationship between the opening force of the lift lever and the position of the lift lever;

7 is a schematic cross-sectional view showing the oil pressure controller of the fourth embodiment.

8A to 8D are partially enlarged diagrams showing the valve opening of the controller of FIG.

9 is a graph showing the relationship between the opening force of the lift lever and the position of the lift lever;

10 shows a hydraulic circuit of a conventional fork lift.

11 shows a hydraulic circuit of a prior art forklift having a lock mechanism.

12 shows another hydraulic circuit of a prior art forklift having a lock mechanism.

It is sectional drawing which expands and shows the needle valve of a prior art.

* Description of the symbols for the main parts of the drawings *

1: industrial vehicle 4: cylinder

6: carrier 14: actuator

18: drain valve 19: ring cage

25: Fastener 27: Lift Control Valve

P; Pump 46,47: lock device

A forklift according to a first embodiment of the present invention is described with reference to FIGS. 1 and 2. In the forklifts of FIGS. 1 and 2, a lock mechanism with a hydraulic circuit as shown in FIG. 11 or 12 is used.

As shown in FIG. 1, the mast 3 is provided in front of the body 2 of the forklift 1. The mast 3 comprises an outer mast 3a and an inner mast 3b. The outer mast 3a is supported on the body 2 to be inclined, and the inner mast 3b is positioned on the outer mast to move up and down along the outer mast 3a. At the rear of the outer mast 3a, the lift cylinder 4 is aligned in parallel with the outer mast 3a. The lift bracket 5 is guided to move up and down along the inner mast 3b. A fork for carrying the load is attached to the lift bracket 5. The chain wheel 7 is supported by each head of the inner mast 3b. The chain 8 is hung on each chain wheel 7. The first end of each chain 8 is connected to the associated upper part of the lift cylinder 8, and the second end of each chain 8 is connected to the lift bracket 5. The fork 6 is moved up and down with the lift bracket 5 along the mast 3 by means of a lift cylinder 4 via a chain 8.

The proximal end of the inclined cylinder 9 is pivotally supported on both sides of the body 3. The distal end of the piston rod 9a is connected to the outside of the outer mast 3a as shown in FIG. 1. The movement of the piston rod 9a tilts the mast.

The steering wheel 11, the lift lever 12, and the inclination lever 13 are provided in front of the driver's room 10. In FIG. 1, the inclined lever 13 is hidden by the lift lever 12. The lift cylinder 4 is operated by a lift lever 12, and the inclined cylinder 9 is operated by an inclined lever 13.

The release lever 14, or actuator, is provided in a predetermined position in front of the front frame 2a. As shown in FIG. 2, the release lever 14 is located inside the housing 15, so that it cannot be moved around indefinitely. The housing 5 has a lid that can be opened and closed.

As shown in FIG. 2, the release lever 14 is pivotally supported by an L-shaped arm 16 fixed to the front frame 2a. The U-shaped link 14a is fixed to the release lever 14. One end of the wire 17 is connected to the U-shaped link 14a and the other end is connected to the link mechanism 19 to release the needle valve 18. A guide 20 is provided between the first wire U-shaped link 14a and the link mechanism 19 to support the wire 17.

The link mechanism 19 includes a support 22 fixed to the housing 18a and a lever 24. The lever 23 includes a force point, a supporting point, and an operating point, and is pivotally connected to the support 22. The proximal end 23a of the lever 23 is pivotally connected to the support 22 by an attachable pin 24. The U-shaped link 21 is fixed to the distal end 23b of the lever 23 by an attachable pin 25. The needle valve 18 is connected to the intermediate position of the lever 23 by an attachable pin 26.

The housing 18a of the needle valve 18 includes oil passages 18a and 18c which are opened and closed by the valve body 18d. The valve body 18d includes a shutter portion 18f and a shaft 18g extending upward from the shutter portion 18f and protruding from the housing 18a. The shutter 18f can be moved axially in the guide hole 18h formed in the housing 18a. The shutter 18f is pressurized to separate the passage 18b from the passage 18c by the force of the coil spring 18e. The coil spring 18e is located between the shutter 18f and the attachment plate 18i fixed to the housing 18a by a screw 18k. A guide hole 18j for accommodating the shaft 18g is formed at the center of the attachment plate 18i. A pivot hole 18m for receiving the pin 26 is formed at the distal end of the shaft 18g. The needle valve 18 connected to the link mechanism 19 via the shaft 18g is fixed at a predetermined position of the body 2. Hydraulic oil flows from the passage 18b to the passage 18c. The passage 18b is connected to the bottom (not shown) of the lift cylinder 4 and the passage 18c is connected to an oil tank (not shown).

The operation of the needle valve 18 is described next. As shown in Fig. 2, the lid 15a of the cover is opened, the release lever 14 is moved in the direction as shown by the arrow, the wire 17 is pulled, and the lever 23 The distal end 23b of is moved upward in FIG. At the same time, the valve body 18d of the needle valve 18 is moved upward with respect to the force of the spring 18e. This point connects the passage 18b to the passage 18c. Therefore, the hydraulic oil in the bottom chamber of the lift cylinder 4 flows to the oil tank, and the fork 6 is lowered. That is, the fork 6 is released or unlocked. If no force is applied to the lever, the valve body 18d is returned to the position for separating the passage 18b from the passage 18c by the force of the spring 18e. At the same time, the lever 23 and the release lever 14 are pulled by the valve body 18d and returned to their normal positions.

The present invention has the following advantages.

(1) The valve body 18d of the needle valve 18 is connected to the link mechanism 19. The link mechanism 19 is connected to the release lever 14 via a wire 17. Thus, the needle valve 18 is easily opened. As a result, even when the operation of the forklift 1 is stopped with the fork 1 in the raised position, the fork 6 can be lowered by releasing the locking action without removing the tool panel.

(2) The proximal end 23a of the lever 23 of the link mechanism 19 is connected to the needle valve 18 by a detachable pin 24, the distal end 23b of which is connected to a detachable pin ( 25 is connected to the U-shaped link (21). The needle valve 18 is connected between the proximal end 23a and the distal end 23b by a detachable pin 26. By squeezing any of the removable pins (removable fasteners 24, 25, 26), the needle valve 18 cannot be actuated by the release lever 14. In other words, the lock release mechanism cannot be operated easily. This eliminates the need to manufacture forklifts that do not lock release action for any customer. This facilitates manufacturing maintenance and reduces manufacturing costs.

(3) The valve body 18d is pressed by a spring 18e to separate the passage 18b from the passage 18c while the lever 14 is not in operation. Thus, since the bottom chamber of the lift cylinder 4 is separated from the oil tank by the shank valve 46 or 47, the fork 6 is well locked when the hydraulic pump is not operated.

(4) Since the release lever 14 is located in the protective housing 15, the lever 14 cannot be operated inadvertently.

The link mechanism 19 can be changed as shown by the second embodiment as shown in FIG. That is, the proximal end 23a of the lever 23 of the link mechanism 19 is connected to the shaft 18g of the needle valve 18 by the pin 24, and the distal end 23b is the pin 26. Is connected between the ends 23a and 23b of the lever 23. The lever 23 is pivotally supported by the support 22. The wire 17 connected to the U-shaped link 21 is connected to the release lever 14 via a guide 20.

In this structure, the release lever 14 is moved as shown by the arrow of FIG. 3, the wire 17 is pulled, and the distal end 23b of the lever 23 is connected to the U-shaped link 21. By moving downward. At the same time, the distal end 23a of the lever 23 moves upward, and the valve body 18d moves upward. Thus, the passage 18b is connected to the passage 18c. When the lever 14 is not forced downward by the application of the force to the lever 14, the wire 17 is loosened, and the valve body 18d passes from the passage 18c to the passage 18b. ) Is returned by the spring 18e to the position where it is separated. Then, the lever 23 and the release lever 14 are returned together with the valve body 18d to their normal state.

The release lever 14 is located in front of the driver's room 10 of the present invention. However, the lever 14 may be located in another position as long as the operation of the lever 14 is not disturbed.

The forklift according to the third embodiment of the present invention will be described with reference to FIGS. 4, 5 (a) to 6 (d), and 6 with respect to the first embodiment. For convenience, like reference numerals are used for structures similar to those in the second embodiment.

As shown in FIG. 4, the lift control valve 27 for controlling the up-down movement of the fork 6 is a directly moving spool valve. The lift control valve 27 acts as the lift control valve 41 in the hydraulic circuit of FIG. 11 or 12. One end of the lift control valve 27 is connected to the proximal end of the connecting rod 28. By the up-down movement of the connecting rod 28, the position of the lift control valve 27 is changed between the positions A ', B', C '. The fork 6 is raised, stopped or lowered according to the positions of the positions A ', B' and C '. The distal end of the connecting rod 28 is pivotally connected to the pivot arm 12a of the lift lever 12. The pivot arm 12a of the lift lever 12 is pivotally supported by the support pin 12b. The lift lever 12 is located in front of the cab shown in FIG. The link mechanism 19 is connected to the connecting rod 28 at a predetermined position.

The distal end 23b of the lever 23 is pivotally connected to the connecting rod 28 by a detachable pin 25. The proximal end 23a of the lever 23 is connected to the shaft 18g of the needle valve 18 via a pin 29. The support 22 is connected to the position between the proximal end 23a and the distal end 23b of the lever 23 by a detachable pin 26. The rectangular hole 18n formed at the distal end of the shaft 18g has a rectangular shape. The rectangular hole 18n allows up-down movement of the pin 29 as shown in diagrams (a)-(d) of FIG.

Next, the operation of the needle valve 18 is described. As shown in FIG. 4, when the lift lever 12 is shifted from the upper position A to raise the fork 6 to the neutral position B to stop the fork 6, the connection is made. The rod 28 is moved downward by the counterclockwise rotation of the lift lever 12. By this movement, the lift control valve 27 is shifted from the position A 'to the position B'. At the same time, the distal end 23b of the lever 23 connected to the connecting rod 28 is moved downward, and the proximal end 23a of the lever 23 is moved upward. The connecting pin 29 fixed to the proximal end of the lever 23 is located slightly above the center of the rectangular hole 18n from the lower end position of the rectangular hole 18n shown by Fig. 5A. It is moved to the position shown in (b). Thus, the valve body 18d remains seated and separates the passage 18b from the passage 18c by the force of the spring 18e.

As shown in FIG. 4, when the lift lever 12 is shifted from the neutral position B to the downward position C to lower the fork 6, the lift lever 12 is counterclockwise. Is rotated in the direction. The connecting rod 28 is then moved further downwards and the lift control valve 27 is shifted from position B 'to position C'. Thus, the fork 6 is lowered as long as the pump operates. The distal end 23b of the lever 23 is moved downward with the connecting rod 28. Then, the proximal end 23a of the lever 23 is moved upward. The pin 29 fixed to the proximal end of the lever 23 is moved from the position shown in Fig. 5 (b) to the position shown in Fig. 5c, and then the position shown in Fig. 5d. The valve body 18d is moved upward. This point connects the passage 18b to the passage 18c. Thus, as long as the pump operates, the hydraulic oil in the bottom chamber of the lift cylinder 4 is returned to the oil tank via the needle valve 18 and the lift control valve 27, which is the point of the fork 6. Descend. When the pump is not operated, the fork 6 continues to descend because the needle valve 18 is open.

On the other hand, when the lift lever 12 is shifted from the position C to the position B or A, the connecting rod 28 is moved upward, and the lift control valve 27 is moved to the position C '. Is shifted to position A '. At the same time, the distal end 23b of the lever 23 connected to the connecting rod 28 is moved upward, and the proximal end 23a of the lever 23 is moved downward. The coupling pin 29 fixed to the proximal end 23a of the lever 23 is from the position shown in Fig. 5 (d) to the position shown in Fig. 5 (b) of Fig. 5 (a). And the needle valve 18 is positioned to separate the passage 18b from the passage 18c.

The oil pressure controller described above has the following advantages.

(1) The distal end 23b of the lever 23 connected to the connecting rod 28 of the lift lever 12 is moved up and down based on the operation of the lift lever 12. The rectangular hole 18n of the shaft 18g of the needle valve 18 allows the up-down movement of the pin 29. Thus, when the lift lever 12 is in the downward position C, the needle valve is opened. When the lift lever 12 is positioned at a position A or B different from position C, for example, the needle valve 18 remains closed. As a result, the fork 6 can be easily lowered by moving the lift lever 12 to the downward position even when the operation of the forklift 1 is stopped.

(2) The lever 23 of the link mechanism 19 is directly connected to the lift lever 12 and moved up and down by operating the lift lever 12. Thus, the release lever 14, the wire 17, the guide portion 20 and the U-shaped links 14a and 21 of FIGS. 2 and 3 can be omitted. This reduces the number of parts and the manufacturing cost.

(3) The distal end 23b of the lever 23 of the link mechanism 19 is connected to the connecting rod 28 by a detachable arm 25, the proximal end 23a of the needle through the pin 29 It is connected to the shaft 18g of the valve 18. In addition, the support 22 is connected to the lever 23 by a detachable pin 26, and the lever 23 is pivotally supported by the support 22. Thus, if the customer does not want to release the lock mechanism, the release action can be easily operated by removing the pin 26 or the pin 25, i.e. separating the lever 23 from the connecting rod 28. There will be no. As a result, there is no need to manufacture two types of forklifts to satisfy any customer. This reduces manufacturing costs, which facilitates manufacturing maintenance.

The lift control valve 27 continuously controls the oil flow from C 'to A' (from position C to A of lift lever 12). The position of the lift lever 12 when the shaft 18g of the needle valve 18 moves from the upper end of the rectangular hole 18n as shown in FIG. 5C is as shown in FIG. It may be a position between position B and C (temporary position). In this case, as shown in FIG. 6, the force for operating the lift control valve 27 is the force of the spring of the lift control valve 27 while the lift lever 12 is in the range AD of the position. Is the force (α) to resist. While the lift lever 12 is within the range of position DC, the force on the spring 18e is added to the force, and the force for operating the lift control valve 27 is greater than the force α. ) When the operator moves the lift lever from position D to C, the rest of the load creates an alert for the operator.

A forklift according to a fourth embodiment of the present invention will be described with reference to FIGS. 7 and 8 (a) to (d). For convenience of description, like reference numerals are used to denote structures similar to those of the third embodiment of FIG.

As shown in FIG. 7, the lower connecting rod 28a is connected to the lift control valve 27, and the separated upper rod 28b is connected to the lift lever 12. The lower connecting rod 28a is connected to the lever 23 by a pivot link 30. One end of the upper rod 28b is pivotally connected to the pivot arm and the other end is pivotally connected to the link 30 by a pin 31. The upper end of the lower rod 28a is pivotally connected to the link 30 by a pin 30a.

When the lift lever 12 is operated between positions A and C, the spool of the lift control valve 27 is moved up and down by springs (not shown) and the lower rod 28a. . The control valve 27 occupies three corresponding positions A ', B', and C ', the spool of the lift control valve 27 is located at position C', and the control valve 27 ) Cannot move further downward. Due to this limitation, the link 30 is rotated in the direction K (clockwise in FIG. 7).

The pin 31 is fixed at a predetermined position of the link 30. The rectangular hole 23c is formed in the distal end 23b of the lever 23. The pin 31 is inserted into the rectangular hole 23c, thus connecting the lever 23 and the link 30. As shown in FIG. 4, the pin 29 is fixed to the proximal end 23a of the lever 23. The pin 29 is inserted into a rectangular hole 18n of the shaft 18g of the needle valve 18, and the lever 23 is connected to the needle valve 18. The support 22 pivotally supports the lever 23 between the proximal end 23a and the distal end 23b by a detachable pin 26.

Next, the operation of the needle valve 18 will be described. As shown in Fig. 7, when the lift lever 12 is shifted from the A position to the B position, the pivot arm 12a of the lift lever 12 rotates counterclockwise. When the connecting rod 28 moves downward by the movement of the pivot arm 12a, the lift control valve 27 is shifted from the A 'position to the B' position. At the same time, the distal end 23b of the lever 23 connected to the connecting rod 28 moves downward. Then, the proximal end 23a of the lever 23 moves upward by the force of the lever. The pin 29 fixed to the distal end 23a of the lever 23 is from the lower end of the rectangular hole 18n as shown by the diagram of Fig. 8A, Fig. 8B. It moves to the intermediate position of the rectangular hole 18n shown by the diagram. Thus, the valve body 18d remains seated, and the passage 18b is separated from the passage 18c by the force of the spring 18e, and the fork 6 is locked.

When the lift lever 12 is shifted from the position of B to the position C, the pivot arm 12a rotates counterclockwise. The connecting rod 28 moves downward by the movement of the pivot arm 12a. Then, the lift control valve 27 is shifted from the position of B 'to the position of C'. At the same time, the distal end 23b of the lever 23 moves downward, and the distal end 23a of the lever 23 moves upward by the force of the lever. The pin 29 fixed to the proximal end 23a of the lever 23 has a rectangular hole shown in (c) of FIG. 8 from an intermediate position of the rectangular hole 18n shown in (b) of FIG. Go to the upper end of 18n). Due to this movement, the needle valve 18 remains seated and separates the passage 18b from the passage 18c. On the other hand, when the oil pump is operated, the lift control valve 27 is shifted in the position of C ', and the fork can be lowered.

When the lift lever 12 is shifted from the position of C to the position of D, the pivot arm 12a of the lift lever 12 rotates counterclockwise. This rotation moves the upper rod 28b of the connecting rod 28 downward. Due to this movement, the link 30 is pivoted in the direction K shown in FIG. This point moves the pin 31 downward, and the distal end 23b of the lever 23 moves upward by the force of the lever. Due to this movement, the pin 29 fixed to the proximal end 23a of the lever 23 moves from the position of FIG. 8C to the position of FIG. 8D. This point moves the valve body 18d upward, which connects the passages 18b and 18c. Therefore, the hydraulic oil in the bottom chamber of the lift cylinder 4 is returned to the oil tank through the needle valve 18 or the shank valve (not shown) and the lift control valve 27. This lowers the fork 6 even when the pump is not running.

On the other hand, when the lift lever 12 is shifted from the position of D to the position of C, the upper rod 28b moves upward, and the link 30 returns to the position shown in FIG. At the same time, the distal end 23b of the lever 23 is moved upward by the pin 31. Then, the proximal end 23a of the lever 23 is moved downward. Due to this movement, the needle valve 18 returns to its neutral position and separates the passage 18b from the passage 18c.

Therefore, the oil pressure controller according to the third embodiment has the following advantages.

(1) There is a lower connecting rod 28a and an upper connecting rod 28b. The lower rod 28a is connected to the upper rod 28b by a link 30. The pin 31 fixed by the link 30 is inserted into a rectangular hole 23c formed in the distal end 23b of the lever 23 and connected to the upper connecting rod 28b. Thus, when the lift lever 12 moves from position A to position C, the needle valve 18 does not open, and the fork 6 does not lower when the hydraulic pump stops. If the lift lever 12 moves from position C to position D, the needle valve is opened by the pivoting movement of the link 30 and the fork 6 is lowered. As a result, when the hydraulic pump is stopped, if the lift lever 12 is accidentally positioned in the downward position by the operator, the fork 6 remains locked. When the forklift 1 is not operated, the fork 6 can be easily lowered by moving the lift lever 12 to position D. FIG.

(2) The lock release action of the needle valve 18 by the lever 14 is not easily operated by detaching the pin 26 if required by the customer.

The present invention can be additionally realized as follows.

The present invention provides a variety of vehicles different from the forklift 1, such as a vehicle having a roll clamp for carrying a paper roll, a block clamp for carrying a block, and a ram for carrying a coiled wire or cylindrical load. Can be applied to

As such, the examples and examples are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

Accordingly, the present invention provides an oil pressure controller of an inexpensive industrial vehicle in which the lock mechanism of attachment of the industrial vehicle is easily released, and also, there is no need to manufacture two types of forklifts to satisfy any customer. Reduce manufacturing costs to facilitate manufacturing maintenance.

Claims (14)

A cylinder 4 for raising and lowering the carrier 6; A pump (P) for supplying fluid to the cylinder (4); A lift control valve (27) for controlling the fluid supply to the cylinder (4) for driving the cylinder (4); Located between the cylinder 4 and the lift control valve 27 to prevent gas flow from the cylinder 4 to prevent the carrier 6 from descending when the pump P is not operating. Lock devices 46 and 47; A drain valve 18 to allow fluid to be drained from the cylinder 4 when opened, The lift control valve 27 is shifted between the first, second and third positions, where the first position causes fluid to flow from the pump P to the cylinder 4 to raise the carrier 6. The second position allows fluid to be drained from the cylinder 4 to lower the carrier 6, the third position stops the fluid supply to the cylinder 4, and to stop the carrier 6 In an oil pressure controller of an industrial vehicle having a rising and falling carrier 6 forbidding fluid drain from a cylinder 4, An oil pressure controller in an industrial vehicle, characterized by an actuator (14) for allowing operation of the drain valve (18) by an operator. The oil of an industrial vehicle according to claim 1, characterized by a transmission mechanism (29) positioned between the actuator (14) and the drain valve (18) for transmitting the movement of the actuator (14) to the drain valve (18). Pressure controller. 3. The oil pressure controller of claim 2, wherein the transmission mechanism (29) is a ring cage (19). 4. The oil pressure controller of claim 3, wherein the link cage (19) comprises a lever. 3. The transmission mechanism (29) according to claim 2, characterized in that the transmission mechanism (29) comprises an easily removable portion, the removal of which prevents the transfer of motion from the actuator (14) to the drain valve (18). Oil pressure controller in industrial vehicle. 6. The oil pressure controller of claim 5, wherein the removable fastener (25) connects the actuator (14) to the transmission mechanism (29). 6. The oil pressure controller of an industrial vehicle according to claim 5, characterized in that the removable fastener (24, 26) connects the drain valve (18) to the transmission mechanism (29). 6. The transmission mechanism according to claim 5, wherein the transmission mechanism 29 comprises a lever having a point of force, a support point and an action point, the point of force being connected to an actuator 14, the support point being connected to a support, At least one of the force point, the support point, and the operating point comprises a removable fastener (24, 25, 26). 9. The oil pressure controller of claim 1, wherein the actuator is located in the cab of the vehicle. 10. 9. The oil pressure controller of claim 1, wherein the protective housing (15) covers the actuator (14). 10. 9. The oil pressure controller of any of claims 1 to 8, wherein the pressure member (18e) presses the drain valve (18) constantly toward the closed position. The oil pressure controller of any of claims 1 to 8, wherein the actuator (14) acts as a lift lever to actuate the lift control valve (27). 13. The oil pressure of an industrial vehicle according to claim 12, wherein the drain valve (18) is opened by the actuator (14) after the lift control valve (27) is shifted to the second position by the actuator (14). Controller. 13. The oil of an industrial vehicle according to claim 12, wherein the actuator (14) is shifted between a range of motion and a range of motion for shifting the position of the lift control valve (27) and the position for opening the drain valve (18). Pressure controller.