JPH05319B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for operating a load push-pull in a load push-pull type lift truck.

Conventional technology and its problems In recent years, for lift trucks such as forklifts, when loading and unloading cargo onto a loading section such as a fork or platen, the cargo is synchronized in the opposite direction to the movement of the lift truck. There is a so-called load push-pull type lift truck designed to improve the efficiency of cargo handling operations. This lift truck is
For example, as disclosed in Japanese Patent Application Laid-open No. 57-195098,
It is equipped with a pantograph-like push-pull mechanism that moves back and forth on the platen by hydraulic operation, and a gripper mechanism that is provided on the face plate disposed at the tip of this push-pull mechanism and grips and releases the sheet pallet by hydraulic operation. and,
When stacking the cargo on the platen, first, the gripper mechanism grips the sheet pallet placed under the cargo and moves the lift truck forward, and at this time, the push-pull mechanism is moved backward in synchronization with the amount of advance of the lift truck. It becomes possible to stack the cargo on the platen without moving the position of the cargo. On the other hand, when loading and unloading cargo from the platen, the push-pull mechanism is advanced in synchronization with the retreat of the lift truck, causing the face plate to push out the cargo, making it possible to load and unload the cargo without changing its position.

By the way, the load push-pull operating device disclosed in JP-A-57-195098 is provided with a vehicle speed detector and a face plate speed detector in order to automatically synchronize the movement of the push-pull mechanism and the movement of the lift truck. Since the oil amount controller is controlled based on the signals from both of these detectors, the device becomes complicated. Therefore, we attempted to greatly simplify the structure by directly operating the push-pull mechanism and gripper mechanism with an oil discharge means that is driven by the movement of the vehicle and discharges an amount of oil corresponding to the amount of ground movement of the vehicle. This has been proposed by the present applicant in Japanese Patent Application No. 306,800/1983.

However, in the load push-pull device using the oil discharge means as described above, hydraulic oil is supplied to the push-pull mechanism and the gripper mechanism by the movement of the lift truck. For this reason, when stacking items on the platen, the gripper mechanism is activated first, and after the gripping operation is completed, the push-pull mechanism is activated.In other words, the hydraulic oil supplied from the oil discharge means is First, it is supplied to the gripper mechanism and then to the push-pull mechanism. Therefore, if the face plate of the push-pull mechanism is too close to the load, the face plate will move backwards as the vehicle moves before the gripper mechanism has fully gripped the sheet pallet, that is, when the push-pull mechanism is not operated at all. There was a problem in that there was a risk that the load would be pressed without being pushed, causing the load to collapse.

Therefore, the present invention provides an arrangement in which the gripper mechanism can be operated independently when the lift truck is stopped, without depending on the oil discharging means driven by the movement of the vehicle. All oil is used in the push-pull mechanism,
It is an object of the present invention to provide a load push-pull actuating device for a lift truck that can immediately operate a push-pull mechanism when a vehicle is moved.

Means for Solving the Problems In order to achieve the above object, the load push-pull actuating device for a lift truck of the present invention has a face plate provided above the load carrying part, and the face plate a push-pull mechanism that moves the sheet pallet back and forth using hydraulic pressure; a gripper mechanism provided on the face plate that grips and releases the sheet pallet using hydraulic pressure; and a control valve that supplies and shuts off working fluid to the push-pull mechanism and the gripper mechanism. In the load push-pull type lift truck, the load on the sheet pallet gripped or released by the gripper mechanism is moved back and forth in synchronization with the direction opposite to the movement of the vehicle by the push-pull mechanism. A hydraulic circuit leading to the push-pull mechanism and the gripper mechanism,
A manual circuit that supplies hydraulic pressure by lever operation in manual mode, and an auto circuit that supplies hydraulic fluid in an amount approximately corresponding to the amount of ground movement of the vehicle through a hydraulic fluid discharge means driven by vehicle movement in auto mode. are arranged in parallel, and a manual circuit hydraulic pressure generating means for supplying hydraulic fluid to the manual circuit in the auto mode is provided, and on the upstream side of the hydraulic fluid supply circuit of the push-pull mechanism,
A pressure control valve is provided to first supply the supplied hydraulic fluid to the gripper mechanism, and operation completion detection means is provided to detect when gripping or releasing of the gripper mechanism is completed, and the hydraulic fluid passes through the manual circuit. The switching valve is configured by providing a switching valve that controls the shutoff and is normally set to the passing side, but is set to the shutoff side when the operation completion detection means detects the gripping or release completion of the gripper mechanism in the auto mode. .

Operation With the above-described configuration, the load push-pull actuating device for a lift truck of the present invention can operate the manual circuit fluid when the vehicle is stopped in the auto mode, that is, when the hydraulic fluid discharge means does not discharge the hydraulic fluid. When the pressure generating means is actuated to supply hydraulic fluid to the manual circuit, the supplied hydraulic fluid is supplied to the gripper mechanism without being supplied to the push-pull mechanism by a pressure control valve provided on the upstream side of the push-pull mechanism. , actuating only the gripper mechanism. When the gripper mechanism has completed gripping or releasing the sheet pallet, the operation completion detection means detects this and sets the switching valve of the manual circuit to the shutoff side. Then, no further hydraulic fluid is supplied through the manual circuit, and the gripper mechanism maintains the gripping or releasing state, and the pressure is controlled by the increase in fluid pressure after the gripper mechanism completes gripping or releasing. The push-pull mechanism is supplied with hydraulic pressure when the valve opens.
No hydraulic fluid is supplied. Therefore, the push-pull mechanism remains inactive. Thereafter, when the vehicle moves, an amount of hydraulic fluid approximately corresponding to the amount of ground movement of the vehicle is supplied from the hydraulic fluid discharge means to the auto circuit, but the hydraulic fluid from this auto circuit has already been gripped or released by the gripper mechanism. Once completed, it is immediately supplied to the push-pull mechanism. Therefore, the push-pull mechanism is operated in synchronization with the movement of the vehicle without delaying the start of movement of the vehicle.

Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

That is, FIG. 1 shows a load push-pull actuating device 10 for a lift truck showing one embodiment of the present invention.
This load push-pull actuating device 10 is used, for example, in a lift truck 100 as shown in FIG. That is, this lift truck 100 is a so-called load push-pull type lift truck, and a platen 101 (fork) serving as a cargo loading portion is mounted on a mast 10 erected in front of a vehicle body 102.
3, 104 via a lift cylinder 105 so as to be movable up and down, and a load push pull 110 is integrally attached above the platen 101. The platen 101 is mounted on a rail 106 fixed to a lift bracket (not shown) that moves along the masts 103 and 104 so as to be movable left and right. The load push-pull 110 includes a push-pull mechanism 111 and a gripper mechanism 112, and the push-pull mechanism 111 is supported integrally with the platen 101 on the rail 106 so as to be movable left and right, as shown in FIG. Pantograph-shaped link mechanism 113
, a face plate 114 attached to the tip of this link mechanism 113 , and a face plate 114 attached to the tip of this link mechanism 113 .
The push-pull cylinder 115 is configured to extend and contract using hydraulic pressure. On the other hand, the gripper mechanism 112
It consists of a grip part 116 provided at the lower end of the gripper which can be opened and closed in the vertical direction, and a gripper cylinder (not shown) that opens and closes the grip part 116 using hydraulic pressure.

The masts 103 and 104 are of a tilt type that can be tilted forward, and are tilted via a tilt cylinder (not shown), and
The platen 101 and the load push pull 1
10 is adapted to be side-shifted via a shift cylinder (not shown).

Furthermore, in the lift truck 100 of this embodiment, a seat retainer 117 is attached to the lower end of the rail 106 for use when recovering a sheet pallet placed under cargo. This sheet retainer 117 is provided with a grip portion for gripping a sheet pallet, similar to the gripper mechanism 112, and this grip portion is operated by a sheet retainer cylinder (not shown).

By the way, the load push-pull actuating device 10 shown in FIG. 1 particularly shows a hydraulic circuit 12 for actuating the load push-pull 110 and the seat retainer 117, and 115 in the figure is a push-pull cylinder, 118 is a gripper cylinder, and 119 is a seat retainer cylinder. The push-pull cylinder 115 and the gripper cylinder 118 are arranged in parallel with each other, and the push-pull cylinder 115 has a rearward cylinder chamber 115a.
and the grip side cylinder chamber 118a of the gripper cylinder 118 are connected to the first hydraulic pressure supply circuit 14, and the push side cylinder chamber 115b of the push-pull cylinder 115 and the release side cylinder chamber 118b of the gripper cylinder 118 are connected to the first hydraulic pressure supply circuit 14. and are connected to the second hydraulic pressure supply circuit 16. A counterbalance valve 2 as a pressure control valve is provided upstream of the hydraulic fluid supply circuits 18 and 20 of the push-pull cylinder 115, which communicate with the first and second hydraulic pressure supply circuits 14 and 16, respectively.
Further, on the upstream side of the counterbalance valves 22 and 24, an electromagnetic switching valve 26 for supplying and cutting off hydraulic oil to the push-pull cylinder 115 is provided. Note that among the counterbalance valves 22 and 24, the extrusion side cylinder chamber 115
The balance valve 24 in b can be replaced with a throttle valve with a check valve. Further, the seat retainer cylinder 119 is arranged in parallel with the push-pull cylinder 115, and the supply and cutoff of hydraulic oil to the seat retainer 119 is performed by the electromagnetic switching valve 26. That is, the grip side cylinder chamber 119a of the seat retainer cylinder 119 is connected to the second hydraulic pressure supply circuit 16, and the release side cylinder chamber 119b is connected to the first hydraulic pressure supply circuit 14. When the electromagnetic switching valve 26 cuts off the hydraulic oil supply to the push-pull cylinder 115, the first and second hydraulic pressure supply circuits 14, 16
The hydraulic oil is supplied to the seat retainer cylinder 119. Furthermore, on the upstream side of the seat retainer cylinder 119, there is a throttle valve 2 with a check valve on the side communicating with the grip side cylinder chamber 119a.
8, and a pilot check valve 30 which uses the hydraulic pressure on the second hydraulic pressure supply circuit 16 side as a pilot pressure is provided on the side communicating with the release side cylinder chamber 119b. The push-pull cylinder 115, the gripper cylinder 118, the seat retainer cylinder 119, and the counterbalance valve 2
2 and 24 and the electromagnetic switching valve 26 constitute a push-pull sequence circuit 32.

The push-pull sequence circuit 32 is supplied with hydraulic oil whose source pressure is the oil discharged from an engine-driven oil pump 36 via a control valve 34. The control valve 34 is of a carry-over type operated by a lever 38, and the operation of the lever 38 switches the hydraulic oil supply to a tilt cylinder, a lift cylinder, a shift cylinder (not shown), and the push-pull sequence circuit 32. It's summery. In addition, when the control valve 34 is in a state where the lever is not operated, the hydraulic oil introduced into the control valve 34 is discharged from the carrier port 34a.

Ports 34b and 34c connected to the push-pull sequence circuit 32 of the control valve 34
and the push-pull cylinder 115 and gripper cylinder 11 of the push-pull sequence circuit 32.
8, the first and second hydraulic pressure supply circuits 1 on the upstream side of the branch point
4 and 16 refer to the third and fourth hydraulic pressure supply circuits 40 and 4.
A manual circuit 44 is formed between the control valve 34 and the push-pull sequence circuit 32 via the third and fourth hydraulic pressure supply circuits 40 and 42. On the other hand, the carryover port 34a of the control valve 34
is connected to an orbiter 48 as a hydraulic fluid discharge means via a circuit 46, and left and right discharge ports 48a, 48b of the orbiter 48 are connected via fifth and sixth hydraulic pressure supply circuits 50, 52. , are connected to the first and second hydraulic pressure supply circuits 14 and 16 of the push-pull sequence circuit 32, similarly to the third and fourth hydraulic pressure supply circuits 40 and 42, respectively. Then, from the carryover port 34a of the control valve 34, an auditorium 48 and a third,
The auto circuit 54 is connected to the push-pull sequence circuit 32 via the fourth hydraulic pressure supply circuits 50 and 52.
is configured. and a manual mode in which hydraulic pressure is supplied to the push-pull sequence circuit 32 via the manual circuit 44 by operating the lever 38 when the load push-pull 110 is operated;
An auto mode in which hydraulic pressure is supplied by the orbiter 48 via an auto circuit 54 can be switched by a mode changeover switch 56. Note that even when the mode changeover switch 56 is switched to the auto mode, hydraulic oil can be supplied to the manual circuit 44 by operating the lever 38 of the control valve 34, and the lever 38 controls the manual circuit hydraulic pressure. It functions as a generating means. Further, the position of this lever 38 is input to a controller 58.

The orbiter 48 is generally known as a control valve for power steering for cargo handling vehicles, and its function is to discharge an amount of oil corresponding to the amount of rotation input to the input shaft, for example, the rotation angle of the steering wheel. It's getting old,
This discharged oil is used for steering.

FIG. 4 is a cross section of the orbiter 48,
In the housing 200, left and right discharge ports 48a and 48b are formed spaced apart in the axial direction, and a pump port 201 and a tank port 202 are formed spaced apart in the circumferential direction from the left and right discharge ports 48a and 48b. There is. The left discharge port 48a is connected to the fifth hydraulic pressure supply circuit 50 of the auto circuit 54, and the right discharge port 48b is connected to the sixth hydraulic pressure supply circuit 52.
It is connected to the. In addition, the pump port 201 is a carryover port 34a of the control valve 34.
The tank port 202 is connected to a reservoir tank 60 via a drain circuit 58 .

A cylindrical sleeve 203 is fitted into the housing 200, and a cylindrical spool 204 is closely fitted into the sleeve 203 so as to be relatively rotatable.
04 has the respective ports 48a, 48b, 201,
202 are formed with appropriate passages. A gear pump 206 is provided at one end of the housing 200 (the right end in the figure), and the internal teeth 205 are eccentric from the central axis.
7 are locked and connected in the rotational direction. The spool 204, the sleeve 203, and the drive 207 are connected to a pin 20 arranged in a direction perpendicular to the axis.
They are connected to each other via 8.
At this time, the pin 208 is fitted into the sleeve 203 and the drive 207 without any play, but it is fitted into the spool 204 with some play in the circumferential direction (for example, a rotation angle of 10 degrees). ing.
Further, a leaf spring 209 is provided between the spool 204 and the sleeve 203, and the leaf spring 209 centers the spool 204 and the sleeve 203 in the rotational direction. Furthermore, an input shaft 62 (see FIG. 1) is spline-fitted into the spool 204 at the other end of the housing 200 (left end in the drawing).
A rolling element 64 is fixed to the input shaft 62, and the rolling element 64 is pressed against the upper outer periphery of the tire 66, so that when the vehicle moves (forward or backward), the tire is
66 rotations, the rolling element 64 rotates, and rotational force is input to the orbit roll 48 via the input shaft 62.

When the orbit roll 48 is in a neutral state where no rotational force is input, the spool 204 and the sleeve 203
is centered and pump port 201
The hydraulic oil introduced from the left and right discharge ports 48
It is returned to the reservoir tank 60 from the tank port 202 without being discharged from a, 48b.
Next, when the vehicle is moving, when rotational force is input to the spool 204 via the input shaft 62, the spool 204
04 and the sleeve 203 are rotated relative to each other, and the hydraulic oil introduced from the pump port 201 is transferred to the gear pump 2.
Supplied within 06. Then, the internal teeth 205 of the gear pump 206 are moved from the spool 2 by the hydraulic pressure at this time.
04 rotates, and at this time, when the vehicle is in forward motion, hydraulic oil is supplied to the right discharge port 48.
When the vehicle is in a backward state, the hydraulic oil is discharged from the left discharge port 48a. Furthermore, when the internal teeth 205 rotate, the drive 207 and pin 2 rotate accordingly.
08, the sleeve 203 connects to the spool 2.
Rotate to follow the 04 rotation. Therefore, while the spool 204 continues to rotate, the sleeve 203 continues to follow with a slight phase difference, and hydraulic oil is continuously discharged from the right discharge port 48b or the left discharge port 48a, and this hydraulic oil The total discharge amount is approximately proportional to the amount of movement of the vehicle. Also,
When the push-pull cylinder 115 is operated by the hydraulic oil discharged from the orbit roll 48,
Face plate 11 of push-pull mechanism 111
4 is the push-pull cylinder 115 so that it is moved substantially synchronously in the opposite direction to the longitudinal movement of the vehicle.
, the discharge amount of the orbit roll 48, or the diameter of the rolling element 64 are determined. In detail, in this embodiment, the operating amount of the push-pull mechanism 111 is set to be slightly ahead of the discharge amount of the orbit roll 48. By doing so, the amount of movement of the vehicle and the amount of movement of the face plate 114 are actually generally synchronized.

By the way, when the orbiter 48 is used as a power steering system, the steering function is maintained even when the hydraulic pump stops operating due to an engine failure or the like. That is, a passage 210 that short-circuits a tank port 201 and a pump port 202 is formed in the housing 200, and generally, by strongly steering the steering wheel, the spool 204,
Internal tooth 205 via pin 208 and drive 207
When the gear pump 206 is forced to rotate, a negative pressure is generated within the gear pump 206. Then, the hydraulic oil in the reservoir tank communicating with the tank port 201 flows backward into the gear pump 206 through the passage 210, and this backward flowing hydraulic oil is discharged from the right discharge port 48b or the left discharge port 48a. A so-called hand pump action is performed, and the steering function is exerted by this hand pump action. Accordingly, the passage 210 is provided with a check valve 211 that shuts off the passage 210 when the hydraulic pump is normal, and communicates the passage 210 when the hydraulic pump is out of order.

However, when the general orbit roll 48 in which such a passage 210 is formed is used in the auto circuit 54 of the load push-pull actuator 10 of this embodiment, the hydraulic oil is supplied from the carryover port 34a of the control valve 34. is cut off, that is, when hydraulic oil is not supplied from the oil pump 36 to the orbiter 48,
When the vehicle moves, the hydraulic fluid in the reservoir tank 60 is sucked up, and this sucked up hydraulic fluid is transferred to the fifth tank.
The pressure is supplied to the push-pull sequence circuit 32 via the hydraulic pressure supply circuit 50 or the sixth hydraulic pressure supply circuit 52, leading to malfunction of the load push-pull 110.

Therefore, in this embodiment, when using the orbit roll 48 in which the passage 210 is formed,
It is designed to eliminate the adverse effects of the hand pump action of the orbiter 48. That is, one solution is to install the fifth and sixth hydraulic pressure supply circuits 5 on the downstream side of the orbiter 48 as shown in FIG.
A normally open first electromagnetic on-off valve 68 is provided between 0 and 52, and the first electromagnetic on-off valve 68 is closed when auto mode is selected.
The valve is closed. Therefore, when the first electromagnetic on-off valve 68 is opened, the hydraulic oil discharged from one of the left and right discharge ports 48a and 48b of the orbiter 48 flows through the first electromagnetic on-off valve 68. The left and right discharge ports 48a, 48
b, and the orbiter 48
is in an idling state, and hydraulic oil is prevented from flowing into the push-pull sequence circuit 32 from the auto circuit 54.

Furthermore, in the load push-pull actuating device 10 of this embodiment, a normally closed second electromagnetic on-off valve 70 as a switching valve is provided between the third and fourth hydraulic pressure supply circuits 40 and 42 of the manual circuit 44. In addition, the load push pull 110 is provided with a gripper mechanism 11.
As an operation completion detection means for detecting the completion of gripping or release of the push-pull mechanism 111,
A stroke sensor 72 is provided to detect the movement stroke of No. 4. That is, when the hydraulic oil is supplied to the push-pull mechanism 111, the counterbalance valves 22 and 24 first supply the hydraulic oil to the gripper mechanism 112 and gripping or releasing is completed. By detecting when the mechanism 111 starts operating, it is possible to detect the completion of the operation of the gripper mechanism 112. Note that the grip detection means is not limited to the stroke sensor 72, and for example, although not shown, the gripper mechanism 1
It may be a limit switch that directly detects the amount of movement of the 12 grip portions 116, or a pressure sensor that detects the hydraulic pressure acting on the counterbalance valves 22, 24.

The detection signal from the stroke sensor 72 and the switching signal from the mode selection switch 56 are input to the controller 58, and when the stroke sensor 72 detects gripping completion when the vehicle is stopped in the auto mode, the controller 58
A switching signal is output from 8 to the second electromagnetic on-off valve 70. Note that when the second electromagnetic on-off valve 70 is opened, the manual circuit 4
4, the hydraulic oil can be supplied to the push-pull sequence circuit 32, and the second electromagnetic on-off valve 70 is opened, so that the hydraulic oil bypasses the second electromagnetic on-off valve 70, The supply of hydraulic fluid to the push-pull sequence circuit 32 is cut off.

On the other hand, the controller 58 is further provided between the fifth and sixth hydraulic pressure supply circuits 50 and 52 of the auto circuit 54.
A normally-closed third electromagnetic on-off valve 74 is provided, which is opened and closed by a drive signal from the drive signal. The amount of hydraulic fluid used is now controlled. Incidentally, the third electromagnetic on-off valve 74 is provided with an orifice 76.

Furthermore, the second electromagnetic on-off valve 7 of the manual circuit 44
The third and fourth hydraulic pressure supply circuits 40 and 42 on the downstream side and the first and third electromagnetic on-off valves 6 of the auto circuit 54
8, 74 downstream side fifth and sixth hydraulic pressure supply circuits 50,
52 includes a pilot check which uses the hydraulic pressure of the opposite circuits of the third and fourth hydraulic pressure supply circuits 40 and 42 and the fifth and sixth hydraulic pressure supply circuits 50 and 52, which are paired with each other, as a pilot pressure. Valve 76, 76
a, 78, 78a are provided. The pilot check valves 76, 76a prevent the hydraulic oil from the manual circuit 44 from flowing into the auto circuit 54 when the hydraulic oil is being supplied from the manual circuit 44 to the push-pull sequence circuit 32, and
The pilot check valves 78 and 78a are designed to prevent hydraulic oil from the auto circuit 54 from flowing into the manual circuit 44 when hydraulic oil is being supplied from the auto circuit 54 to the push-pull sequence circuit 32. .

Note that the electromagnetic switching valve 26 provided in the push-pull sequence circuit 32 normally connects the first and second hydraulic pressure supply circuits 14 and 16 to the push-pull cylinder 1.
15 side, and is operated by a drive signal output from the controller 58.

The oil pump 36, which is a source of hydraulic pressure to the hydraulic circuit 12, also supplies hydraulic oil to the power steering (not shown), and the distribution of hydraulic oil to the hydraulic circuit 12 and the power steering is as follows: This is done by a diversion valve 80.

The operation of the load push-pull actuating device 10 of this embodiment with the above configuration will be explained below using the flowchart shown in FIG. Note that this flowchart shows an example of a process in which the controller 58 executes a control program.

That is, in the flowchart above, turn on the power
However, when the mode changeover switch 56 is switched to the manual side, the manual mode is set in step 300. In the manual mode, the first electromagnetic on-off valve 68 of the hydraulic circuit 12 is set to the open side, the second electromagnetic on-off valve 70 is set to the closed side, and the third electromagnetic on-off valve 74 is set to the closed side. Further, if the manual mode is set in step 300, step 30
1, the stroke sensor 72 determines the initial position of the face plate 114 of the push-pull mechanism 111.
S ₀ is detected, and the initial rotation angle θ ₀ (θ ₀ =k・S ₀ )k of the orbiter 48 corresponding to this initial position S ₀ is:
The coefficients are determined based on the detection signal from the rotary encoder 65 and stored.

In the next step 302, the mode changeover switch 5
6 is switched to the auto side. If the auto mode is not set (NO), the process returns to step 300, while if the auto mode is set (YES), the process proceeds to the next step 303.
Note that when the auto mode is set, the first electromagnetic on-off valve 68 is switched to the closing direction, and is set in a state where the hydraulic oil discharged from the orbiter 48 can be supplied to the push-pull sequence circuit 32. be done. In step 303, the position of the lever 38 as a manual circuit hydraulic pressure generating means is detected, and the lever 38 is in the neutral position, that is, the carryover port 34a of the control valve 34.
Is the state in which hydraulic oil is supplied to the orbit roll 48 from the push position, that is, the manual circuit 44
It is determined whether hydraulic oil is supplied to the fourth hydraulic pressure supply circuit 42 of the manual circuit 44 or whether hydraulic oil is supplied to the third hydraulic pressure supply circuit 40 of the manual circuit 44 in the pull position. Then, the step 30
If the lever 38 is determined to be in the neutral position in step 3, the process jumps to step 304, if it is determined to be the push position, the process proceeds to step 305, and if it is determined to be the pull position, the process proceeds to step 306. .

In step 304, the second electromagnetic on-off valve 70 is switched to the opening direction, the hydraulic oil supplied from the third hydraulic pressure supply circuit 40 or the fourth hydraulic pressure supply circuit 42 is bypassed, and the push-pull sequence is activated from the manual circuit 44. The state is such that the supply of hydraulic oil to the circuit 32 can be cut off. On the other hand, if the push position or pull position is determined in step 303, the second electromagnetic on-off valve 70 is in the closed state at this point, so the fourth hydraulic pressure supply circuit 42 or the third hydraulic pressure supply The hydraulic oil discharged into the circuit 40 is supplied to the push-pull sequence circuit 32. Then,
The push-pull sequence circuit 32 has counterbalance valves 22 and 24 connected to the push-pull cylinder 11.
5, the hydraulic oil is first supplied to the gripper cylinder 118.
When the lever 38 is in the push position, hydraulic pressure is supplied to the release side cylinder chamber 118b of the gripper cylinder 118, and the grip part 116 is
When the lever 38 is released and the lever 38 is in the pull position, hydraulic pressure is supplied to the grip side cylinder chamber 118a of the gripper cylinder 118 to grip the grip portion 116. Then, in steps 305 and 306, it is determined whether the gripper mechanism 112 has completed release or gripping. The completion of this release or gripping is performed by the stroke sensor 72, and the completion of release is detected when the extrusion operation of the face plate 114 starts, and the completion of gripping is detected when the retraction operation of the face plate 114 starts. Then, the step 30
When it is determined in step 5 that the release of the gripper mechanism 112 has been completed and that the gripping of the gripper mechanism 112 has been completed in step 306 (YES), the process advances to step 304 and the second electromagnetic on-off valve 7 is opened.
0 to open the valve, and the supply of hydraulic fluid from the manual circuit 44 to the push-pull sequence circuit 32 is cut off. Therefore, the gripper mechanism 1
12 is put on standby when release or gripping is completed. If it is determined in step 305 that the release has not been completed, the process returns to step 302, and if it is determined in step 306 that the grip has not been completed, the process returns to step 300. By the way, when the operation (release, gripping) of the gripper mechanism 112 is completed in steps 305 and 306,
Upon visual confirmation by the operator, the lever 38 of the control valve 34 is returned to the neutral position and hydraulic oil is supplied from the carrier port 34a.
When the operation is completed, the pilot lamp is turned on or a sound is emitted, thereby making it easier to confirm the completion of the operation.

Next, in step 307, it is determined whether the lever 38 of the control valve 34 is in the neutral position, that is, whether the lever 38 is in the manual circuit 44 or not.
Of course, it is determined that the cylinder is not in the supply position to the tilt cylinder, the lift cylinder, and the side shift cylinder. If it is determined that it is not in the neutral position (NO), the process returns to step 302 again.
If it is determined that the vehicle is in the neutral position (YES), hydraulic oil is being supplied from the carrier over port 34a to the orbit roll 48, and when the vehicle is moved, hydraulic oil is supplied from the orbit roll 48. can be discharged. At this time, since the first electromagnetic on-off valve 68 was switched to the closed side when switching to the auto mode, the hydraulic fluid discharged from the orbiter 48 is
It becomes possible to supply the signal from the auto circuit 54 to the push-pull sequence circuit 32. Therefore, the hydraulic fluid discharged from the orbit roll 48 due to vehicle movement is supplied to the push-pull sequence circuit 32 via the auto circuit 54, but the gripper mechanism 112 generally does not complete its release or grip operation. Therefore, the counterbalance valves 22 and 24 are in an open state, and the hydraulic fluid is immediately supplied to the push-pull cylinder 115. Therefore, the push-pull mechanism 111 operates substantially simultaneously with the start of vehicle movement, and when the vehicle is moving backward, the face plate 114 moves forward in synchronization with this, and when the vehicle moves forward, the face plate 114 moves back in synchronization with this. Therefore, in auto mode, the face plate 11
4, no relative movement with respect to the ground occurs when the vehicle moves forward or backward, and it appears that the load supported by the face plate 114 is lowered from the platen 101 in a fixed position when the vehicle backs up. The cargo on the sheet pallet gripped by the gripper mechanism 112 as it moves forward is loaded onto the platen 101 at a fixed position. When loading and unloading this cargo, there is no delay in the operation of the push-pull mechanism 111 immediately after the start of vehicle movement.
There will be no problems such as cargo collapse.

In this way, in the auto mode, the push-pull mechanism 111 is operated in synchronization with the movement of the vehicle.
After it is determined in step 307 that the face plate 114 is in the neutral position, in step 308 the amount of movement of the face plate 114 from the reference value (S+S ₀ ) is determined.
is detected by the stroke sensor 72, and the rotational angular displacement (θ=θ+θ ₀ ) of the orbiter 48 from the reference value due to vehicle movement is calculated. and,
After the next step 309, the push-pull mechanism 11
1 operational correction is performed. That is, step 309
Then, the rotational angular velocity of the orbiter 48 (dθ/
dt) is detected, and the operating state of the push-pull mechanism 111 is determined based on the positive or negative relationship of this rotational angular velocity. When the rotational angular velocity is zero, the orbiter 48 is stopped.
That is, it indicates that the vehicle is stopped, and in this case, the process returns to step 302 without performing correction control.

Next, if the rotational angular velocity is positive, it is determined that the vehicle is in a backward state (i.e., PUSH state), and the process proceeds to step 310, and if the rotational angular velocity is negative, the vehicle is in a forward state (i.e., PULL state). It is determined that this is the case, and the process proceeds to step 311. In step 310, it is determined whether the amount of movement S of the face plate 114 determined in step 308 has reached the maximum amount δa, and if it has reached δa (YES).
The process proceeds to step 312, where the first electromagnetic on-off valve 68 is turned on.
By switching to OFF, that is, to the valve open side, the hydraulic oil discharged from the orbiter 48 is bypassed via the first electromagnetic on-off valve 68, and the supply of hydraulic oil to the push-pull sequence circuit 32 is cut off. The operation of the push-pull cylinder 115 is stopped. On the other hand, if it is determined in step 310 that the face plate 114 has not reached the maximum amount δa (NO), the process proceeds to step 313, where the first electromagnetic on-off valve 68 is kept ON, that is, in the closed state. In step 314, it is determined whether the difference between the actual stroke S of the face plate 114 and the target stroke kθ determined from the rotation angle of the orbit roll 48 is larger than a positive value ζ close to zero. In other words, it is determined whether the face plate 114 has moved too much than the target value, and if it has moved too much (YES), the process advances to step 315.
The third electromagnetic on-off valve 74 is turned on, that is, switched to the open side to bypass the hydraulic oil, temporarily stopping the operation of the push-pull cylinder 115, and then returning to step 302. On the other hand, if the determination in step 314 is NO, then step 3
Proceed to step 16 and turn off the third electromagnetic on-off valve 74.
That is, the valve is switched or maintained in the closed state to supply hydraulic oil to the push-pull cylinder 115, and then the process returns to step 302. Therefore, the third electromagnetic on-off valve 74 is used for correction control.

Next, in step 311, it is determined whether the movement amount S of the face plate 114 has reached the minimum amount δb, and if it has reached δb (YES), the process proceeds to step 317, and the first electromagnetic on-off valve 68 is turned off.
Make it. If δb has not been reached (NO), proceed to step 318, turn on the first electromagnetic on-off valve 68,
Proceeding to step 319, it is determined whether the difference between the actual stroke S and the target stroke kθ is smaller than a negative value -ξ close to zero. If YES, the process proceeds to step 320, where the third electromagnetic on-off valve 74 for correction control is turned on, and the process returns to step 302; if NO, the process proceeds to step 321, where the third electromagnetic on-off valve 74 is turned on.
The electromagnetic on-off valve 74 is turned off and the process returns to step 302.

In addition, the load push-pull actuating device 1 described above
0 indicates operation in the automatic mode, but when operating in the manual mode, the second electromagnetic on-off valve 70 is held in the closed state, and the operation of the lever 38 causes the manual circuit 44 to be switched from the push-pull sequence circuit 32. Hydraulic oil is supplied and gripper mechanism 1
12 and push-pull mechanism 111 can be operated.

In this embodiment, pilot check valves 76 and 76a are provided in the third and fourth hydraulic pressure supply circuits 40 and 42 of the manual circuit 44 and the fifth and sixth hydraulic pressure supply circuits 50 and 52 of the auto circuit 54, respectively. ,78,
78a, the hydraulic oil supplied to the push-pull sequence circuit 32 is not discharged even when the hydraulic oil supply from the manual circuit 44 or the auto circuit 54 is stopped, The hydraulic pressure within the sequence circuit 32 can be maintained. Further, the pilot check valves 76, 76a, 78, 78a are connected to the auto circuit 54.
This prevents hydraulic oil from flowing into the manual circuit 44 during operation, and prevents hydraulic oil from flowing into the auto circuit 54 when the manual circuit 44 operates. In particular, when the latter manual circuit 44 is operated, hydraulic pressure flows into the orbit roll 48 of the auto circuit 54, so that the orbit roll 4
8, it is possible to prevent abnormal vibrations from occurring. Incidentally, the pilot check valve 76,
76a, 78, and 78a may be replaced with electromagnetic on-off valves that are opened and closed as appropriate by drive signals output from the controller 58.

Furthermore, in this embodiment, one push-pull sequence circuit 32 is shared and the manual circuit 44 and auto circuit 54 are arranged in parallel, so if the auto circuit 54 fails, the manual circuit 44 can be used as fail-safe means. Can be used.

Also, in manual mode, auto circuit 5
Due to the rotation of the rolling elements 64, the orbit roll 48 of No. 4 sucks up the hydraulic oil in the reservoir tank 60, and the left discharge port 48a or the right discharge port 4
8b, but this discharged hydraulic oil is bypassed via the first electromagnetic on-off valve 68 because the first electromagnetic on-off valve 68 is normally open. The load push pull 110 is supplied to the push pull sequence circuit 32.
can be prevented from being erroneously activated.

In this embodiment, the push-pull sequence circuit 32 is controlled by switching the electromagnetic on-off valve 26 provided in the push-pull sequence circuit 32 to the supply side to the seat retainer cylinder 119. The supplied hydraulic oil can be supplied to the seat retainer cylinder 119, the sheet retainer 117 can grip the sheet pallet instead of the gripper mechanism 112, and the sheet pallet can be recovered when unloading the cargo.

FIG. 6 shows a load push-pull actuating device 10a showing another embodiment, in which the same components as in the previous embodiment are designated by the same reference numerals and redundant explanations will be omitted.

That is, in this embodiment, when the manual mode is selected, the orbiter 48 is used as a means for preventing hydraulic oil from being supplied to the push-pull sequence circuit 32 by the hand pump action of the orbiter 48.
An electromagnetic clutch 80 that is disconnected and engaged by a drive signal output from the controller 58 is provided on the input shaft 62 of the controller 58, and the first electromagnetic on-off valve 68 used in FIG.
has been abolished.

Therefore, in this embodiment, in the manual mode, by disconnecting the electromagnetic clutch 80, the rotational force when moving the vehicle is transferred to the orbiter 4.
8 and, therefore, the orbiter 48 is not operated, thereby preventing hydraulic oil from being sucked up and discharged from the reservoir tank 60.

FIG. 7 shows a load push-pull actuating device 10b showing yet another embodiment, in which the same components as in the previous embodiment are given the same reference numerals.

That is, in this embodiment, when the auto mode is selected, the gripping and releasing operations by the gripper mechanism 112 are performed by the button 82 as a manual circuit hydraulic pressure generating means, and the control is performed by the control valve 80 on the downstream side of the oil pump 36. A diversion valve 84 is further provided between the valve 34 and the hydraulic oil diverted by the diversion valve 84 so that it can be supplied to the manual circuit 44 via a newly provided electromagnetic switching valve 86.
The electromagnetic switching valve 86 has a neutral position where the hydraulic oil introduced from the diverter valve 84 is returned to the reservoir tank 88, a gripper gripping side position where it supplies the hydraulic oil to the third hydraulic pressure supply circuit 40, and a fourth hydraulic pressure supply circuit 42.
and a gripper release side position, and these positions can be appropriately switched by a drive signal from a controller 58.

Therefore, in this embodiment, by turning on the button 82 in the auto mode, this signal is input to the controller 58, and the electromagnetic switching valve 86 is turned on.
Hydraulic oil is supplied to the third hydraulic pressure supply circuit 40 or the fourth
is supplied to the hydraulic pressure supply circuit 42, and the gripper mechanism 1
Grasp or release 12. At this time, when gripping and releasing are completed, this is detected by the stroke sensor 72.
is detected, the electromagnetic switching valve 86 is switched to the neutral position via the controller 58, and the supply of hydraulic oil to the manual circuit 44 is stopped.

As described above, in this embodiment, the preliminary operation of the gripper mechanism 112 in the auto mode is controlled by the lever 38.
Since this is done automatically by operating the button 82 without having to operate the button 82, the operability is greatly improved.

Incidentally, in the embodiment shown in FIG. 1, the first electromagnetic on-off valve 68 is provided in order to eliminate the adverse effects of the hand pump action of the orbiter 48, and in the embodiment shown in FIGS. Although the electromagnetic clutch 80 is disclosed, the present invention is not limited to this, and the orbiter 4 shown in FIG.
The hand pump action may be prevented by eliminating the passage 210 itself. If a general power steering orbiter is used instead, this can also be achieved by keeping the check valve 211 provided in the passage 210 closed at all times. That is, FIG. 8 shows the check valve 211, in which the ball 212 opens and closes the valve seat 213, thereby opening and closing the passage 210.
It's starting to shut off. Normally, the retainer 214 side is placed downward as shown in the figure, and if no oil is supplied at this time, the balls 212 fall onto the retainer 214 and open the valve, but the oil discharged from the oil pump 36 When the ball 212 is supplied from the opening 214a of the retainer 214, the ball 212 is lifted and closes the valve seat 213. Therefore, in order to eliminate the hand pump action, the orbiter 48 itself may simply be placed upside down, as shown in FIG. 9A.
The ball 212 is dropped onto the valve seat 213 as shown in FIG.
The valve may be kept closed at all times. Further, in this case, the retainer 214 can be removed as shown in FIG. 9B. Furthermore, as shown in FIG. 9C, a spacer 215 is inserted between the ball 212 and the retainer 214 to move the ball 212 to the valve seat 21 without reversing the orbit roll 48.
The valve may be held in the closed state by pressing the valve to the position 3.

Effects of the Invention As explained above, the load push-pull operating device for a lift truck of the present invention has the following effects.

In the auto mode, the system is driven by the rotation of the tires caused by the movement of the vehicle, and supplies the push-pull mechanism with an amount of hydraulic fluid approximately corresponding to the amount of ground movement of the vehicle through means for discharging hydraulic fluid approximately proportional to the amount of movement of the vehicle. The amount of movement of the push-pull mechanism can be made to correspond to the amount of ground movement of the vehicle.

In the auto mode, only the gripper mechanism operates without operating the push-pull mechanism to grip or release the sheet pallet due to the pressure control valve provided upstream of the push-pull mechanism. When the operation completion detection means detects the completion of gripping or releasing the gripper mechanism, the supply of hydraulic fluid is cut off by the switching valve, so that the hydraulic fluid is subsequently discharged from the hydraulic fluid discharge means of the automatic circuit as the vehicle moves. The hydraulic fluid can be immediately supplied to the push-pull mechanism because the gripper mechanism has already completed its operation.

For this reason, the push-pull mechanism can operate almost simultaneously with the start of vehicle movement, and the amount of movement corresponds to the amount of vehicle movement, so it is possible to accurately guide the load and prevent cargo from collapsing. I can do it.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of a load push-pull operating device for a lift truck according to the present invention, and FIG. 2 is a system diagram showing an embodiment of a lift truck in which the load push-pull operating device of the present invention is used. 3 is a plan view of the push-pull mechanism used in the present invention, FIG. 4 is a sectional view showing an embodiment of the hydraulic fluid discharge means used in the present invention, and FIG. 5 is a plan view of the push-pull mechanism used in the present invention. A flowchart showing an example of a process for executing a control program for a pull actuating device, FIGS. 6 and 7 are system diagrams showing other embodiments of the present invention, and FIG. 8 shows an operation used in the present invention. FIGS. 9A, B, and C, which are enlarged sectional views of main parts of the liquid discharging means, are sectional views corresponding to FIG. 8 showing other embodiments of the hydraulic fluid discharging means used in the present invention. 10, 10a, 10b...Load push-pull actuating device, 12...Hydraulic circuit, 14, 16, 18, 2
0, 40, 42, 50, 52...hydraulic pressure supply circuit, 2
2, 24...Counter balance valve (pressure control valve),
32...Push-pull sequence circuit, 34...Control valve, 38...Lever (manual circuit hydraulic pressure generation means), 44...Manual circuit, 48...Orbitroll (hydraulic fluid discharge means), 54...Auto circuit, 56...Mode Changeover switch, 58... Controller, 70... Second electromagnetic on-off valve (switching valve), 72
...Stroke sensor (operation completion detection means), 82
...Button (manual circuit hydraulic pressure generation means).

Claims (1)

[Scope of Claims] 1. A push-pull mechanism that has a face plate provided above the cargo placement part and moves the face plate back and forth using hydraulic pressure, and a push-pull mechanism that is provided on the face plate and moves the sheet pallet using hydraulic pressure. A gripper mechanism that grips and releases the sheet pallet, and a control valve that supplies and shuts off hydraulic fluid to these push-pull mechanisms and gripper mechanisms, and the push-pull mechanism moves the cargo on the sheet pallet gripped or released by the push-pull mechanism in the opposite direction to the movement of the vehicle. In a load push-pull type lift truck that moves back and forth in synchronization with a direction, a manual supplying hydraulic pressure to a hydraulic circuit from the control valve to the push-pull mechanism and the gripper mechanism by operating a lever in manual mode. An automatic system that supplies an amount of hydraulic fluid that approximately corresponds to the amount of ground movement of the vehicle through a circuit and a means that is driven by the rotation of the tires as the vehicle moves in auto mode and discharges hydraulic fluid that is approximately proportional to the amount of movement of the vehicle. A manual circuit hydraulic pressure generating means is provided for supplying hydraulic fluid to the manual circuit in the auto mode, and a hydraulic fluid pressure generating means is provided on the upstream side of the hydraulic fluid supply circuit of the push-pull mechanism. A pressure control valve that first supplies hydraulic fluid to the gripper mechanism is provided, and operation completion detection means is provided to detect when gripping or release of the gripper mechanism is completed, and passage or interruption of the hydraulic fluid in the manual circuit is provided. A lift truck characterized in that it is provided with a switching valve that is normally set to the passing side, but is set to the blocking side when the gripping or releasing completion of the gripper mechanism is detected by the operation completion detection means in the automatic mode. Load push-pull actuator.