JPS6320720Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a swinging fork clock device for a forklift, which is equipped with a fork device capable of rotating in a horizontal direction.

Prior Art Conventionally, this type of locking device includes, for example, a locking rod provided on a shift carriage that rotatably supports a fork device, and a spring inserted into a recessed portion of a cam provided on a rotating shaft for pivoting the fork. A device is known in which the fork device can be locked in a specific position (usually in three positions: the center position where the fork is directly in front of you and the turning end position where the fork is facing directly to the side) by elastically engaging the fork device through the fork. As another example, a lock rod operated by a cylinder is provided on the shift carriage, and the rod can be inserted into and removed from a lock plate provided on the finger bar of the fork device at the end of the rotation where the fork device faces directly to the side. something is known.

However, in the former case, since the locking rod is a forced release type in which the fork device is rotated with the locking rod always pressed against the cam by a spring, wear problems occur due to resistance to the rotation operation, and the rotation operation is also delayed. It lacks smoothness and is accompanied by shock. On the other hand, in the latter case, the fork locks only at the end of the turn, and cannot be locked at the center position where the fork faces directly ahead.Therefore, when traveling to transport cargo, etc., the fork may wobble or sway due to vibrations. However, there are problems such as impact force caused by vibration being applied to the swing drive system.

OBJECTS OF THE INVENTION It is an object of the invention to provide a locking device for a swinging fork in a forklift, which is improved so as to eliminate the drawbacks of the prior art devices mentioned above.

Composition of the invention The present invention includes a shift carriage that supports a fork device so as to be able to pivot in the horizontal direction via a rotating shaft.
A hydraulic circuit for a swing cylinder that swings the fork device includes a normally closed hydraulic circuit for directional control, and a lock cylinder having a lock member that is always urged in a direction in which the lock cam fixed to the rotation shaft comes into contact with the lock cam via an elastic body. A normally open solenoid selector valve for direction control is incorporated in the hydraulic circuit for the lock cylinder, and the normally open solenoid selector valve closes with a delay after the lock cylinder is unlocked, and the normally open solenoid selector valve closes after the lock cylinder is unlocked. The valve is provided with control means for controlling the valve to open when the lock cylinder is opened. This control means includes, for example, a switch for detecting lock release and a delay timer.

Embodiments Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. A shift carriage 3 is attached to a lift bracket 1 that moves up and down along the mast of a forklift so that it can move left and right via a side shift device 2. The shift carriage 3 extends horizontally toward the front and has a fork device attached to its tip. 4 is attached via a rotating shaft 5 so as to be pivotable in the horizontal direction. Rotating shaft 5
is provided with a pinion 6 in the center thereof, and the pinion 6 meshes with a rack 9 that is laterally moved by a pair of left and right turning cylinders 8 that are fixed laterally to the back surface of the finger bar 7 of the fork device 4. That is, the fork device 4 is rotated via the rack 9 and pinion 6 using the rotation cylinder 8 as a driving source.

Further, a lock cam 10 having three recesses 10a at every 90 degrees on the outer circumferential surface is fixed to the lower end of the rotating shaft 5, and on the other hand, opposite to this, the lower surface of the shift carriage 3 has two lock cams for a fork clock. A rod-shaped lock cylinder 11 is fixed. The lock cylinder 11 is equipped with a lock roller 12 at the tip of the rod 11a on the lock cam 10 side, which can be engaged with and detached from the recess 10a of the lock cam 10. It is biased in the direction that it comes into contact with.

Figure 3 shows the swing cylinder 8 and lock cylinder 1.
As shown in the figure, the circuit connecting the control valve 14 for cylinder control and the swing cylinder 8 is a 4-port, 2-position type (hereinafter referred to as "swing type") whose normal position is the closed position.
A solenoid switching valve 15 is incorporated. In addition, a 4-port, 2-position (hereinafter referred to as "lock") electromagnetic switching valve 16 whose normal position is the open position is incorporated in the circuit connecting the control valve 14 and the lock cylinder 11. A check valve 17 is installed on the upstream side (control valve side) so that the hydraulic oil from the hydraulic pump P is supplied only to the lock release side oil chamber 11c of the lock cylinder 11.

The two electromagnetic switching valves 15 and 16 are connected to a limit switch for detecting lock release, which is attached to the shift carriage 3 so as to be operated by the other rod 11b of the lock cylinder 11.
It is now controlled based on the LS signal.
That is, as shown in Figure 4, the limit switch
A timer TM and a relay R are connected in parallel to the LS, and the normally open contact Ra of the relay R is connected to the solenoid SOL1 of the electromagnetic switching valve 15 for turning.
A contact TMa of the timer TM is connected to a solenoid SOL2 of the electromagnetic switching valve 16 for locking.

This embodiment is configured as described above,
The effect will be explained below. As shown by the imaginary line in FIG. 1, for example, when the control valve 14 is manually switched from the neutral position shown in the figure to the operating position on the right or left side with the fork device 4 moved to one side, the pressure from the hydraulic pump P is Since hydraulic oil is supplied to the lock release side oil chamber 11c of the lock cylinder 11 through the lock electromagnetic switching valve 16 in a conductive state, the lock roller 12 at the tip of the rod resists the spring 13 and moves into the recess 10a of the lock cam 10. It is removed from the camera and the tracking clock is released. At that time, the other rod 11b of the lock cylinder 11
contacts limit switch LS and turns it on, so that relay R and timer TM are energized, respectively, and solenoid SOL1 is energized by turning on normally open contact Ra of relay R. Therefore, the electromagnetic switching valve 15 for swinging is switched from the closed position shown in the figure to the open position side and becomes conductive, so that hydraulic oil is supplied to the left and right swinging cylinders 8, and is transferred to the fork via the rack 9 and pinion 6. The device 4 is swiveled to the right or to the left. On the other hand, when a certain period of time has elapsed after the start of the turning operation, the contact TMa is turned on due to the time up of the timer TM, and the solenoid SOL
2 is energized, so the locking solenoid switching valve 16
is switched from the open position shown to the closed position (with only the pump port in a locked passage connection configuration). Therefore, lock cylinder 1
One lock release side oil chamber 11c and the other oil chamber 11d
The lock roller 12 is brought into contact with the outer peripheral surface of the lock cam 10 by the spring 13.

When the fork rotation progresses in this state and the recess 10a of the lock cam 10 faces the rock roller 12, the rock roller 12, which is pressed by the spring 13, engages with the recess 10a and locks the turning fork. 11b separates from the limit switch LS and turns it off.
The power supply to relay R and timer TM is cut off, and the excitation of each solenoid SOL1 and SOL2 is released. Therefore, the electromagnetic switching valve 15 for swinging is returned to the closed position, and the electromagnetic switching valve 16 for locking is returned to the open position, stopping the swinging of the fork device 4, and preparing for the next lock release. .

Effects of the invention As described above, the invention makes it possible to release the lock before the fork device turns.
In addition, when the lock is locked, the swing can be stopped at the same time as the lock, which prevents the generation of shock unlike the conventional forced release type, allowing smooth swing, reducing wear, and reducing the turning force. It does not extend to the locking device side, and the locking device of the present invention can lock the fork device in three or more positions.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; FIG. 1 is a plan view showing the locking device of the swing fork, FIG. 2 is a side view, FIG. 3 is a hydraulic circuit diagram of the swing cylinder and lock cylinder, and FIG. FIG. 3 is an electric circuit diagram for controlling an electromagnetic switching valve. DESCRIPTION OF SYMBOLS 1... Lift bracket, 2... Side shift device, 3... Shift carriage, 4... Fork device, 5... Rotating shaft, 8... Swivel cylinder, 10
...Lock cam, 11 ...Lock cylinder, 12
...Lots Crawler, 13...Spring, 15,
16... Solenoid switching valve, LS... Limit switch.

Claims (1)

[Scope of utility model registration request] In a forklift, a fork device is attached to a shift carriage which is attached to a lift bracket so as to be movable horizontally via a side shift device, and a fork device is attached so as to be pivotable in the horizontal direction via a rotation shaft, and the shift carriage has the rotation axis. A lock cylinder is provided with a lock member that is always urged to come into contact with a lock cam fixed to the shaft through an elastic body, and the hydraulic circuit for the swing cylinder that swings the fork device has a normally closed circuit for directional control. A normally open solenoid selector valve for direction control is incorporated in the hydraulic circuit for the lock cylinder, and the normally open solenoid selector valve closes with a delay after the lock cylinder is unlocked, and the normally open solenoid selector valve closes after the lock cylinder is unlocked. A locking device for a swinging fork in a forklift, which is provided with a control means for controlling a valve to communicate with the opening of a lock cylinder.