JP2010037017A - Fork shift device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To synchronize right and left shift cylinders, without using a synchronous valve in a cylinder type fork shift device which is used for adjusting the interval of forks. <P>SOLUTION: The diameters of the right and left shift cylinders 4, 5 are differentiated, and the rod-chamber side pressure-receiving area B of the large-diameter shift cylinder 4 and the tail-chamber side pressure receiving area B of the small-diameter shift cylinder 5 are equalized. A difference shift cylinder 6, provided with a cylinder chamber 17 with a pressure receiving area D equivalent to the difference between the tail chamber side pressure-receiving area A of the large-diameter shift cylinder 4 and the rod chamber side pressure-receiving area C of the small-diameter shift cylinder 5, is arranged so as to compensate the actuation of the small-diameter shift cylinder 5. The tail chamber 13 of the large-diameter shift cylinder 4 and the rod chamber 16 of the small-diameter shift cylinder 5 are connected to the secondary side of a control valve 18, respectively by supply and discharge pipes 7, 8. The rod chamber 14 of the large-diameter shift cylinder 4 and the tail chamber 15 of the small-diameter shift cylinder 5 are connected by a communicating pipe 9. The rod chamber 16 of the small-diameter shift cylinder 5 and the cylinder chamber 17 of the difference shift cylinder 6 are connected by a conduction pipe 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an improvement in a cylinder-type fork shift device that is mounted on a cargo handling vehicle such as a forklift and is used when adjusting the distance between forks according to the size of a load.

Conventionally, as this type of cylinder-type fork shift device, for example, the one described in Patent Document 1 is known.
The fork shift device includes a carriage that can be moved up and down, left and right forks provided on the carriage so as to be laterally movable, left and right shift cylinders that are provided symmetrically on the carriage and laterally move the fork, and both shifts. A tail chamber side supply / discharge pipe that connects the cylinder tail chambers to the secondary side of the control valve, and a rod chamber side supply pipe that connects the rod chambers of both shift cylinders to the secondary side of the control valve. The exhaust pipe is composed of a discharge valve and a tuning valve provided in both supply and discharge pipes to synchronize the left and right shift cylinders.

Japanese Patent Laid-Open No. 11-209092

  However, such a device cannot synchronize the left and right shift cylinders unless a tuning valve is used. For this reason, there is a problem that the structure becomes complicated and the cost is high.

  The present invention was devised in view of the above-mentioned problems, and was devised to solve this problem. A fork shift that can synchronize the left and right shift cylinders without using a tuning valve. To provide the equipment.

  The fork shift device of the present invention basically includes a carriage that can be moved up and down, left and right forks provided on the carriage so as to be laterally movable, and a large-diameter shift cylinder provided on a side for laterally moving one of the forks. A small-diameter shift cylinder provided to move the other fork laterally so that the pressure-receiving area on the tail chamber side is equal to the pressure-receiving area on the rod chamber side of the large-diameter shift cylinder, and a large-diameter provided to supplement the operation of the small-diameter shift cylinder A differential shift cylinder having a cylinder chamber with a pressure receiving area corresponding to the difference between the pressure receiving area on the tail chamber side of the shift cylinder and the pressure receiving area on the rod chamber side of the small diameter shift cylinder, and the secondary of the tail chamber of the large diameter shift cylinder and the control valve A large-diameter shift cylinder supply / exhaust pipe connecting the side, a small-diameter shift cylinder supply / exhaust pipe connecting the rod chamber of the small-diameter shift cylinder and the secondary side of the control valve, and a large diameter A communicating pipe connecting the rod chamber and a tail compartment of the small-diameter shift cylinder of Futoshirinda lies characterized in that consisted the conduit which connects the rod chamber and the cylinder chamber of the differential shift cylinder of small diameter of the shift cylinder.

When pressure oil is supplied to the rod chamber of the small-diameter shift cylinder via the small-diameter shift cylinder supply / exhaust pipe by operating the control valve, the small-diameter shift cylinder is shortened and the fork on the same side is moved outward (or inward). When the small-diameter shift cylinder is shortened, the pressure oil in the tail chamber of the small-diameter shift cylinder is sent to the rod chamber of the large-diameter shifted cylinder through the communication pipe, and this is shortened. When the large-diameter shifted cylinder is shortened, the pressure oil in the tail chamber is returned to the control valve via the large-diameter shifted cylinder supply / discharge pipe. When the large-diameter shifted cylinder is shortened, the fork on the same side is moved outward (or inward) symmetrically with the fork on the opposite side. For this reason, the left and right forks are moved outward (or inward) together so that the distance between them is increased and adjusted.
At this time, pressure oil is supplied from the small diameter shift cylinder supply / exhaust pipe to the cylinder chamber of the differential shift cylinder via the conducting pipe, and the differential shift cylinder is operated in the same direction as the operating direction of the small diameter shift cylinder. That is, the shortening operation of the small diameter shift cylinder is compensated by the operation of the differential shift cylinder.

When pressure oil is supplied to the tail chamber of the large-diameter shift cylinder via the large-diameter shift cylinder supply / discharge pipe by operating the control valve, the large-diameter shift cylinder is extended and the fork on the same side moves inward (or outward) Is done. When the large-diameter shift cylinder is extended, the pressure oil in the rod chamber is sent to the tail chamber of the small-diameter shifted cylinder through the communication pipe and is extended. When the small-diameter shifted cylinder is extended, the pressure oil in the rod chamber is returned to the control valve via the small-diameter shifted cylinder supply / discharge pipe. When the small-diameter shifted cylinder is extended, the fork on the same side is moved inward (or outward) symmetrically with the fork on the opposite side. For this reason, the left and right forks are moved inward (or outward) together so that the distance between them is increased and adjusted.
At this time, the pressure oil in the cylinder chamber of the differential shift cylinder is recirculated from the conduction pipe to the control valve via the small diameter shift cylinder supply / discharge pipe, so that the differential shift cylinder is operated in the same direction as the operation direction of the small diameter shift cylinder. . That is, the extension operation of the small diameter shift cylinder is supplemented by the operation of the differential shift cylinder.

  The rod chamber side pressure-receiving area of the large-diameter shift cylinder and the tail chamber-side pressure-receiving area of the small-diameter shift cylinder are made equal by changing the diameters of the left and right shift cylinders, and the tail chamber of the large-diameter shift cylinder and the rod chamber of the small-diameter shift cylinder are Are connected to the secondary side of the control valve by a supply / discharge pipe (large diameter shift cylinder supply / discharge pipe, small diameter shift cylinder supply / discharge pipe), and the large diameter shift cylinder rod chamber and small diameter shift cylinder tail chamber communicate with each other. Because it is connected with, the left and right forks can be opened and closed in synchronization without using a tuning valve.

  A differential shift cylinder having a cylinder chamber with a pressure receiving area equivalent to the difference between the pressure receiving area on the tail chamber side of the large diameter shift cylinder and the rod chamber side pressure receiving area of the small diameter shift cylinder is provided to supplement the operation of the small diameter shift cylinder, and the small diameter Since the rod chamber of the shift cylinder and the cylinder chamber of the differential shift cylinder are connected by a conducting tube, the opening speed and the closing speed of the left and right forks can be made the same.

  The differential shift cylinder is preferably provided as a ram cylinder while being provided symmetrically with the small-diameter shift cylinder around the other fork. In this way, the structure can be simplified and the cost can be reduced.

  It is preferable that at least one of the large-diameter shift cylinder supply / exhaust pipe and the small-diameter shift cylinder supply / exhaust pipe and the communication pipe are connected by a communication pipe provided with a throttle valve. In this way, for example, pressure oil from a large diameter shift cylinder supply / discharge pipe or a small diameter shift cylinder supply / discharge pipe can be replenished to the connecting pipe, so even if the diameters of the large diameter shift cylinder and the small diameter shift cylinder are different. The two can be reliably synchronized.

According to the present invention, the following excellent effects can be achieved.
(1) Carriage, fork, large-diameter shift cylinder, small-diameter shift cylinder, differential shift cylinder, large-diameter shift cylinder supply / exhaust pipe, small-diameter shift cylinder supply / exhaust pipe, communication pipe, conducting pipe, The rod chamber side pressure receiving area of the large diameter shift cylinder and the tail chamber side pressure receiving area of the small diameter shift cylinder are made equal by changing the cylinder diameter, and the tail chamber of the large diameter shift cylinder and the rod chamber of the small diameter shift cylinder are supplied respectively. The exhaust pipe is connected to the secondary side of the control valve, and the rod chamber of the large-diameter shift cylinder and the tail chamber of the small-diameter shift cylinder are connected by a communication pipe, so that the left and right forks can be opened and closed without using the tuning valve. Can be synchronized.
(2) The left and right shift cylinders have different diameters so that the rod chamber side pressure receiving area of the large diameter shift cylinder is equal to the tail chamber side pressure receiving area of the small diameter shift cylinder. The rod chamber is connected to the secondary side of the control valve with a supply and discharge pipe, and the rod chamber of the large-diameter shift cylinder and the tail chamber of the small-diameter shift cylinder are connected with a communication pipe. In comparison, even if the loads on the left and right shift cylinders fluctuate, these can be reliably synchronized.
(3) The fork that is laterally moved by the small-diameter shift cylinder is provided with a cylinder chamber having a pressure-receiving area corresponding to the difference between the pressure-receiving area of the tail chamber side of the large-diameter shift cylinder and the pressure-receiving area of the rod chamber side of the small-diameter shift cylinder. The differential shift cylinder is arranged to supplement the operation of the small-diameter shift cylinder, and the rod chamber of the small-diameter shift cylinder and the cylinder chamber of the differential shift cylinder are connected by a conducting tube, so the opening speed and the closing speed of the left and right forks are the same. Can be made.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic rear view showing a fork shift device of the present invention.

  The fork shift device 1 includes a carriage 2, a fork 3, a large-diameter shift cylinder 4, a small-diameter shift cylinder 5, a differential shift cylinder 6, a large-diameter shift cylinder supply / exhaust pipe 7, a small-diameter shift cylinder supply / exhaust pipe 8, a communication pipe 9, and a continuity. The main part is comprised from the pipe | tube 10, and is applied to cargo handling vehicles, such as a forklift.

The carriage 2 can be moved up and down and is not shown, but the left and right lift brackets, the upper and lower finger bars provided on the front sides thereof, and the left and right sides provided to connect these end portions to each other. A plate is provided.
Although not shown, both lift brackets are lifted and lowered by a lifting device (mast device) of the cargo handling vehicle.

  The fork 3 is a left and right one provided on the carriage 2 so as to be laterally movable. The fork 3 is substantially L-shaped, and includes a vertical piece 11 and a horizontal piece 12 extending forward from the lower end of the vertical piece 11. It is suspended on the finger bar of the carriage 2 so as to be laterally movable.

The large-diameter shift cylinder 4 is provided so as to laterally move one fork 3 and is a piston cylinder (double-acting hydraulic cylinder) comprising a cylinder body, a piston and a piston rod, and has a tail with a pressure receiving area A. A chamber 13 and a rod chamber 14 having a pressure receiving area B are provided.
In FIG. 1, the large-diameter shift cylinder 4 is arranged on the left side of the left fork 3 so as to move laterally. The tail side is attached to the carriage 2 and the rod side is on the left side. It is attached to the fork 3.
The large-diameter shift cylinder 4 is actually arranged on the right side of the left fork 3 in FIG. 1 so as to move due to space limitations.

The small-diameter shift cylinder 5 is provided to laterally move the other fork 3 so that the tail chamber side pressure receiving area B is equal to the rod chamber side pressure receiving area B of the large diameter shift cylinder 4. Similarly, a piston cylinder (double-acting hydraulic cylinder) including a cylinder body, a piston, and a piston rod is provided, and includes a tail chamber 15 having a pressure receiving area B and a rod chamber 16 having a pressure receiving area C.
In FIG. 1, the small-diameter shift cylinder 5 is arranged to the right of the right fork 3 so as to laterally move the right fork 3, the tail side is attached to the carriage 2, and the rod side is attached to the fork 3. Installed.
Like the large-diameter shift cylinder 4, the small-diameter shift cylinder 5 is actually arranged on the left side of the right fork 3 in FIG. .

The differential shift cylinder 6 is provided to supplement the operation of the small-diameter shift cylinder 5, and the pressure-receiving area corresponding to the difference between the tail chamber-side pressure-receiving area A of the large-diameter shift cylinder 4 and the rod-chamber-side pressure-receiving area C of the small-diameter shift cylinder 5. A cylinder chamber 17 of D (D = A−C) is provided, which is a ram cylinder composed of a ram and a cylinder, and has a single cylinder chamber 17.
In FIG. 1, the differential shift cylinder 6 is arranged to the left of the right fork 3 so as to laterally move the right fork 3, the tail side is attached to the carriage 2, and the ram side to the fork 3. Installed.
The differential shift cylinder 6 is actually arranged on the right side opposite to the small diameter shift cylinder 5 with the right fork 3 as a center so as to be symmetrical.

  The large-diameter shift cylinder supply / exhaust pipe 7 connects the tail chamber 13 of the large-diameter shift cylinder 4 and the A port on the secondary side of the control valve 18.

  The small diameter shift cylinder supply / discharge pipe 8 connects the rod chamber 16 of the small diameter shift cylinder 4 and the B port on the secondary side of the control valve 18.

  The P port on the primary side of the control valve 18 is connected to the pump 19, and the T port on the primary side of the control valve 18 is connected to the tank 20.

  The communication pipe 9 connects the rod chamber 14 of the large diameter shift cylinder 4 and the tail chamber 15 of the small diameter shift cylinder 5.

  The conducting tube 10 connects the rod chamber 16 of the small diameter shift cylinder 5 and the cylinder chamber 17 of the differential shift cylinder 6.

  The large-diameter shift cylinder supply / exhaust pipe 7 and the communication pipe 9 are connected to each other, and the small-diameter shift cylinder supply / exhaust pipe 8 and the communication pipe 9 are connected to each other by a communication pipe 22 having a throttle valve 21.

Next, the operation will be described based on such a configuration.
When the distance between the forks 3 is increased (opened), the control valve 18 is operated to supply the pressure oil from the pump 19 to the rod chamber 16 of the small diameter shift cylinder 5 through the small diameter shift cylinder supply / discharge pipe 8. Then, the small diameter shift cylinder 4 is shortened and the fork 3 on the same side is moved outward. When the small-diameter shift cylinder 5 is shortened, the pressure oil in the tail chamber 15 is sent to the rod chamber 14 of the large-diameter shift cylinder 4 through the communication pipe 9 and shortened. When the large diameter shift cylinder 4 is shortened, the pressure oil in the tail chamber 13 is returned from the control valve 18 to the tank 20 through the large diameter shift cylinder supply / discharge pipe 7. When the large diameter shift cylinder 4 is shortened, the fork 3 on the same side is moved outward. Therefore, the left and right forks 3 are moved outward together as shown by the solid arrows in FIG.
At this time, pressure oil is supplied from the small diameter shift cylinder supply / exhaust pipe 8 to the cylinder chamber 17 of the differential shift cylinder 6 through the conducting pipe 10 to extend the differential shift cylinder 6, and the same direction as the operating direction of the small diameter shift cylinder 5. Operated. That is, the shortening operation of the small-diameter shift cylinder 5 is supplemented by the operation of the differential shift cylinder 6.

Conversely, when the interval between the forks 3 is narrowed (closed), the control valve 18 is operated to supply the pressure oil from the pump 19 via the large diameter shift cylinder supply / discharge pipe 7 to the tail chamber 13 of the large diameter shift cylinder 4. To supply. Then, the large diameter shift cylinder 4 is extended and the fork 3 on the same side is moved inward. When the large-diameter shift cylinder 4 is extended, the pressure oil in the rod chamber 14 is sent to the tail chamber 15 of the small-diameter shift cylinder 5 through the communication pipe 9 and is extended. When the small diameter shift cylinder 5 is extended, the pressure oil in the rod chamber 16 is returned from the control valve 18 to the tank 20 through the small diameter shift cylinder supply / discharge pipe 8. When the small diameter shift cylinder 5 is extended, the fork 3 on the same side is moved inward. For this reason, the left and right forks 3 are moved inward together as shown by the chain line arrows in FIG.
At this time, the pressure oil in the cylinder chamber of the differential shift cylinder 6 is returned from the control pipe 18 to the tank 20 through the small diameter shift cylinder supply / discharge pipe 8 from the conduction pipe 10, so that the differential shift cylinder 6 is shortened and the small diameter shift is performed. The cylinder 5 is operated in the same direction as the operation direction of the cylinder 5. That is, the extension operation of the small diameter shift cylinder 5 is compensated by the operation of the differential shift cylinder 6.

  The diameters of the left and right shift cylinders 4 and 5 are made different so that the pressure receiving area B on the rod chamber 14 side of the large diameter shift cylinder 4 is equal to the pressure receiving area B on the tail chamber 15 side of the small diameter shift cylinder 5. The tail chamber 13 and the rod chamber 16 of the small diameter shift cylinder 5 are connected to the secondary side of the control valve 18 by supply and discharge pipes (large diameter shift cylinder supply and discharge pipes, small diameter shift cylinder supply and discharge pipes) 7 and 8, respectively. Since the rod chamber 14 of the diameter shift cylinder 4 and the tail chamber 15 of the small diameter shift cylinder 5 are connected by the communication pipe 9, the left and right forks 3 can be opened and closed in synchronization without using a tuning valve.

  A differential shift cylinder 6 having a cylinder chamber 17 having a pressure receiving area D corresponding to a difference between a pressure receiving area A on the tail chamber 13 side of the large diameter shift cylinder 4 and a pressure receiving area C on the rod chamber 16 side of the small diameter shift cylinder 5 is a small diameter shift cylinder. Since the rod chamber 16 of the small diameter shift cylinder 5 and the cylinder chamber 17 of the differential shift cylinder 6 are connected by the conducting pipe 10, the opening speed and the closing speed of the left and right forks 3 are made the same. I can do it.

  A communication pipe 21 having a throttle valve 22 is provided between the large-diameter shift cylinder supply / discharge pipe 7 and the communication pipe 9 and between the small-diameter shift cylinder supply / discharge pipe 8 and the communication pipe 9, respectively. Pressure oil from the diameter shift cylinder supply / discharge pipe 7 and the small diameter shift cylinder supply / discharge pipe 8 can be supplied to the communication pipe 9, and the large diameter shift cylinder 4 and the small diameter shift cylinder 5 having different diameters can be reliably synchronized. Can do.

The large-diameter shift cylinder 4 and the small-diameter shift cylinder 5 are attached to the carriage 2 on the tail side in the previous example, but not limited to this, for example, the rod side may be attached to the carriage 2.
The differential shift cylinder 6 is a ram cylinder in the previous example, but is not limited thereto, and may be, for example, a double-action type or a single-action type piston cylinder.
In the above example, the differential shift cylinder 6 is disposed opposite to the small-diameter shift cylinder 5 with the fork 3 interposed therebetween. However, the differential shift cylinder 6 is not limited to this. You may arrange | position in parallel in the same direction. In this case, the rod chamber on the same side as the rod chamber 16 of the small diameter shift cylinder 5 becomes the cylinder chamber 17.
In the previous example, the communication pipe 22 provided with the throttle valve 21 is provided between the large-diameter shift cylinder supply / discharge pipe 7 and the communication pipe 9 and between the small-diameter shift cylinder supply / discharge pipe 8 and the communication pipe 9, respectively. However, the present invention is not limited to this. For example, only one of them may be used.

The outline rear view showing the fork shift device of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fork shift device, 2 ... Carriage, 3 ... Fork, 4 ... Large diameter shift cylinder, 5 ... Small diameter shift cylinder, 6 ... Differential shift cylinder, 7 ... Large diameter shift cylinder supply / discharge pipe, 8 ... Small diameter shift cylinder supply / discharge Pipe, 9 ... Communication pipe, 10 ... Conducting pipe, 11 ... Vertical piece, 12 ... Horizontal piece, 13 ... Tail chamber, 14 ... Rod chamber, 15 ... Tail chamber, 16 ... Rod chamber, 17 ... Cylinder chamber, 18 ... Control Valve, 19 ... Pump, 20 ... Tank, 21 ... Throttle valve, 22 ... Communication pipe, A to D ... Pressure receiving area.

Claims (3)

  Carriage that can be raised and lowered, left and right forks provided on the carriage so as to be laterally movable, a large-diameter shift cylinder that is provided to horizontally move one fork, and a tail that is provided to horizontally move the other fork A small-diameter shift cylinder having a chamber-side pressure receiving area equal to the rod chamber-side pressure-receiving area of the large-diameter shift cylinder, and a tail-chamber-side pressure-receiving area of the large-diameter shift cylinder and the small-diameter shift cylinder A differential shift cylinder having a cylinder chamber having a pressure receiving area corresponding to a difference from the rod chamber side pressure receiving area, and a large diameter shift cylinder supply / exhaust pipe connecting the tail chamber of the large diameter shift cylinder and the secondary side of the control valve; A small-diameter shift cylinder supply / exhaust pipe connecting the rod chamber of the small-diameter shift cylinder and the secondary side of the control valve, and the rod chamber and small-diameter shift cylinder of the large-diameter shift cylinder Fork shift device for a communication pipe which connects the tail chamber, a conduit for connecting the rod chamber and the cylinder chamber of the differential shift cylinder of small diameter shift cylinder, characterized in that consisted.   2. The fork shift device according to claim 1, wherein the differential shift cylinder is provided symmetrically with respect to the small diameter shift cylinder with the other fork as a center, and is a ram cylinder.   2. The fork shift device according to claim 1, wherein at least one of the large-diameter shift cylinder supply / discharge pipe and the small-diameter shift cylinder supply / exhaust pipe and the communication pipe are connected by a communication pipe having a throttle valve.

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