JP3740888B2 - Forklift mast device with hinged fork - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mast device for a forklift having a hinged fork as an attachment, and more particularly to a structure in which a carriage having a hinged fork can be locked to an outer mast as required.
[0002]
[Prior art]
A hinged fork, which is one of the attachments of a forklift, is one in which the fork itself can be tilted by about 45 ° in the vertical direction as described in Japanese Patent Laid-Open No. 5-213592. Often used for transporting
[0003]
[Problems to be solved by the invention]
The conventional hinged fork as described above is designed so that the fork can be actively tilted up and down in order to make it easier to scoop up or pay out log-like logs. The load applied to the hinged fork is basically a downward force, and the downward load is borne by the upward force generated by the lift cylinder as in the case of a general fork.
[0004]
On the other hand, there is a demand that the degree of freedom of the hinged fork is effectively used as it is to generate a force for pressing a specific structure downward with the hinged fork. For example, this corresponds to the case where the body of an automobile that has been scrapped is desired to be crushed without using a press machine. In this case, since the load on the hinged fork inevitably becomes an upward force, the upward load cannot be positively borne by the existing lift cylinder.
[0005]
The present invention has been made based on the background as described above, and an object of the present invention is to provide a structure that can be flexibly adapted to an operation in which an upward load is applied to the hinged fork.
[0006]
[Means for Solving the Problems]
The invention described in claim 1 includes an inner mast that guides and supports a carriage having a hinged fork so as to be movable up and down, and an outer mast that guides and supports the inner mast so that the inner mast can be lifted and lowered. A forklift mast device in which the carriage is moved up and down in conjunction with the inner mast, and is provided with a locking means for locking the carriage to the outer mast so as not to move up and down at an arbitrary position of the lifting stroke. It is characterized by.
In this case, it is desirable that the locking means is an actuator-driven type as described in claim 2.
[0007]
The support form of the hinged fork itself is basically the same as the conventional one. The hinged fork is rotatably supported by a carriage supported and supported by the mast so that it can be moved up and down. The hinged fork is tilted and displaced in the vertical direction in accordance with the expansion and contraction operation of the hinge cylinder.
[0008]
Therefore, in the first aspect of the present invention, when, for example, a force for pressing a specific structure downward is generated by the hinged fork, an upward force is applied to the hinged fork as a load, and this load remains as it is. It will be applied as an upward force to the carriage.
[0009]
Therefore, in such a state, the load applied to the carriage as an upward force is exerted on the outer mast by operating the locking means to lock the carriage to the outer mast so that it cannot be moved up and down and tilting the hinged fork forward. It can be borne directly. As a result, it is possible to easily perform a work for positively pressing a specific structure downward, which has been considered difficult in the past.
[0010]
According to a third aspect of the present invention, as a specific configuration of the locking means, a plurality of lock engaging portions arranged side by side along the vertical direction of the outer mast, and provided on the carriage side and advanced and retracted by the operation of the lock actuator. The lock pin is configured to be locked and unlocked by moving and engaging and disengaging with any of the lock engaging portions.
[0011]
A specific form of the lock engaging portion may be, for example, a groove or a hole, and it may be any structure as long as it can receive the lock pin and mechanically connect the carriage and the outer mast.
[0012]
Therefore, according to the third aspect of the present invention, when the locking operation is performed, the lock pin protrudes from the carriage side to the outer mast side, and the carriage and the outer mast are mechanically connected via the lock pin and the lock engaging portion. Connect to As a result, the upward load applied to the hinged fork is transmitted as it is from the carriage to the outer mast, and finally the counterbalance type vehicle body bears this.
[0013]
The invention according to claim 4 is characterized in that, as a specific configuration of the locking means, the locking operation is possible only when the hinged fork is tilted forward by operation of the hinged fork operating lever. Yes.
[0014]
More specifically, as in the invention described in claim 5, the lock actuator of the lock means is constituted by a hydraulic cylinder, and this hydraulic cylinder is used when the hinged fork is moved forward. It is desirable to lock the lock pin using the hydraulic pressure introduced into one chamber as the operating pressure.
[0015]
Therefore, according to the fourth and fifth aspects of the present invention, when the hinged fork operation lever is slightly operated, the lockable state is obtained, so that the lock state is set at a predetermined timing. If the amount of operation of the hinged fork operating lever is further increased in this state, the hinged fork will be greatly tilted forward, and a specific structure is pressed downward with this hinged fork as described above. Force can be generated, and the outer mast bears the load of the hinged fork as the reaction force at that time.
[0016]
Further, unless the hinged fork operating lever is actively operated, the locking means does not perform the locking operation and is in the unlocked state, so that it does not hinder the lifting operation or other normal cargo handling operations.
[0017]
Furthermore, the invention described in claim 6 is characterized in that, as a further specific configuration of the lock means, the lock means can be locked and unlocked by operating a switch attached to the hinged fork operation lever. Yes.
[0018]
The switch for locking and unlocking operation is preferably provided on the knob of the hinged fork operation lever in consideration of the operability of the operator.
[0019]
Therefore, in the invention described in claim 6, when the hinged fork is tilted forward by the operation of the hinged fork operating lever to generate a force that presses a specific structure downward, the hinged fork operation is performed. If the operator operates the switch at a predetermined timing while the lever is slightly operated, the locking means is activated immediately and the carriage is locked to the outer mast. Therefore, if the amount of operation of the hinged fork operation lever is further increased in this locked state, the hinged fork is further tilted forward and a specific structure is pressed downward while the reaction force is borne by the outer mast as described above. Such a force can be generated.
[0020]
【The invention's effect】
According to the invention described in claim 1, 2, due to the provision of a locking means for locking the disabling elevation relative to the outer masts at any position of the lifting stroke of the carriage with the hinged fork upward counter to the hinged fork Even if it is a work form where force is applied, the upward load of the hinged fork, which is the reaction force, can be transmitted from the carriage to the outer mast to be borne by this outer mast. There is an effect that it is possible to flexibly and effortlessly cope with a work form in which a specific structure is positively pressed downward by a forward tilting operation of the hinged fork.
[0021]
According to a third aspect of the present invention, as a specific configuration of the lock means, the lock engagement portion on the outer mast side and the lock engagement portion provided on the carriage side are moved forward and backward by the operation of the lock actuator. In addition to the effects similar to those of the first and second aspects of the invention, since the lock is made purely mechanically, the operation reliability is high, and the hinged fork There is an advantage that the applied load can be reliably transmitted from the carriage to the outer mast.
[0022]
According to the invention described in claim 4, since the locking operation is possible only when the hinged fork is tilted forward by the operation of the hinged fork operating lever, the same effect as that of the invention described in claim 3 is achieved. In addition, there is an advantage that there is no hindrance to the lift operation and other normal cargo handling operations.
[0023]
Further, according to the invention described in claim 5, since so as to lock operated lock pin oil pressure to be introduced into one chamber of the hinge cylinder during forward tilting operation of the hinged fork as operating pressure, claim 4 In addition to the same effects as those of the invention described in (1), there is an advantage that a special operating pressure source for the locking means is not required.
[0024]
According to the invention described in claim 6, since the locking means can be operated by operating a switch attached to the hinged fork operating lever, in addition to the same effect as that of the invention described in claim 5 Since the locking means can be locked and unlocked while operating the hinged fork operating lever, the operability is excellent.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
1 to 4 are views showing a preferred embodiment of a mast apparatus according to the present invention. In particular, FIG. 1 shows an overall configuration of a hinged fork type forklift, and FIGS. 2 and 3 show a mechanical configuration of a locking means. FIG. 4 shows the hydraulic circuits of the hinged fork and the locking means, respectively.
[0026]
As shown in FIG. 2 in addition to FIG. 1, a mast device 2 including an outer mast 3 and an inner mast 4 is provided at a front portion of a vehicle body 1 of the forklift, and the inner mast 4 has a carriage (lift bracket) as a lifting body. 5 is guided and supported so as to be lifted and lowered in such a manner that it is suspended through a lift chain (not shown). As is well known, the inner mast 4 moves up and down with respect to the outer mast 3 in accordance with the expansion and contraction operation of the lift cylinder 6, and the carriage 5 moves up and down with respect to the inner mast 4. Furthermore, the entire mast device 2 can be tilted forward or backward by operating the tilt cylinder 7 to expand and contract as necessary. An upper beam 12 connects the left and right outer masts 3, 3.
[0027]
As shown in FIG. 4, the hinged fork 8 is rotatably supported on the carriage 5 via a hinge pin 9 so that the hinged fork 8 can be tilted up and down from its horizontal posture position. A piston rod 11 of a hinge cylinder 10 provided on the carriage 5 is connected to the end of the fork 8. Accordingly, the hinged fork 8 is tilted forward or backward according to the expansion / contraction operation of the hinge cylinder 10.
[0028]
As shown in FIGS. 2 and 3, a side bar 13 is fixed to the outer surface of each outer mast 3 along the longitudinal direction thereof. A plurality of lock grooves 14 are arranged in a vertical direction at a predetermined pitch.
[0029]
On the other hand, on the carriage 5 side, lock pin guides 16 are integrally provided so as to protrude from the left and right side brackets 15 forming the carriage 5 itself to the side thereof. The lock pin guide 16 is positioned in a non-contact state immediately before the outer and inner masts 3 and 4, and moves up and down together with the carriage 5.
[0030]
In addition, a cylinder bracket 17 having a substantially L-shape is integrally fixed to each lock pin guide 16 toward the front side. The lock pin guide 16 and the cylinder bracket 17 have the same axis in the front-rear direction. Guide holes 18 and 19 located on the line are individually formed. A round bar-like lock pin 21 is supported in these guide holes 18 and 19 via a bush 20 so as to be slidable in the front-rear direction, and the carriage 5 is in a predetermined height position as will be described later. When the lock pin 21 is slid toward the side bar 13, the lock pin 21 is engaged with one of the lock grooves 14 to lock the carriage 5 with respect to the outer mast 3 so that the carriage 5 cannot be moved up and down. It has become.
[0031]
Further, the cylinder bracket 17 is provided with a hydraulic cylinder type lock cylinder 22 functioning as a lock actuator in parallel with the lock pin 21. The lock cylinder 22 is fixed to the cylinder bracket 17 by a pair of lock nuts 23, and a joint 24 connected to the tip of the piston rod is connected to a small-diameter portion in the middle portion in the longitudinal direction of the lock pin 21. As the lock cylinder 22, a spring return type single-acting cylinder type is used as schematically shown in FIG.
[0032]
Accordingly, the lock pin 21 is slid and moved under a predetermined stroke in accordance with the expansion / contraction operation of the lock cylinder 22 so that the lock pin 21 engages or disengages from the lock groove 14, and this causes the carriage 5 to move relative to the outer mast 3. It can be locked or unlocked. As is clear from the above description, the lock groove 25 formed on the side bar 13, the lock pin 21, the lock cylinder 22, and the like form a lock device 25 that is a lock means that controls locking and unlocking of the carriage 5 with respect to the outer mast 3. Has been.
[0033]
FIG. 4 shows details of the hydraulic circuit of the operating system of the hinged fork 8 and the lock cylinder 22, and the hydraulic circuit 26 of the hinged fork 8 is similar to the conventional hydraulic circuit in that it includes a hydraulic pump 27 and a drain tank 28. The control valve 29 and the hinged fork operation lever 30 are provided. The control valve 29 is switched according to the operation of the hinged fork operation lever 30, and the hinged fork 8 is tilted forward or It moves backward. In the present embodiment, the hydraulic circuit 31 of the lock cylinder 22 is provided in a manner of branching from the pipe line connecting the hinge cylinder 10 and the control valve 29 in the hydraulic circuit 26 of the hinged fork 8. .
[0034]
More specifically, the pipe line 32 branched from the pipe line connecting the one chamber 10a on the side of the hinge cylinder 10 that tilts the hinged fork 8 forward and the control valve 29 is the lock cylinder 22 on the lock operation side. Connected to the chamber 22a, a solenoid valve 33 is provided in the branch line 32. As a result, the lock cylinder 22 switches the solenoid valve 33 on the condition that the hydraulic pressure is introduced into the chamber 10a on the hinged fork forward tilt side of the hinge cylinder 10 by the operation of the hinged fork operation lever 30. The lock is activated according to the situation.
[0035]
On the other hand, the knob 34 of the hinged fork operation lever 30 is provided with an operation switch 35, and the solenoid valve 33 is switched according to the ON / OFF operation of the operation switch 35. As a result, the lock cylinder 22 is locked or unlocked. The lock state can be selectively switched.
[0036]
Here, a case will be described in which a downward pressing force is generated on the hinged fork 8 to positively push down a specific structure by using the forward tilting operation of the hinged fork 8.
[0037]
First, the hinged fork operation lever 30 is slightly pressed forward from the neutral position in a state where the carriage 5 is held at a predetermined height position by operating a lift lever (not shown). As a result, the control valve 29 is switched, and the hydraulic pressure from the hydraulic pump 27 is introduced into one chamber 10a of the hinge cylinder 10, so that the hinged fork 8 can be moved forward by further pressing the hinged fork operating lever 30. It becomes possible to assume an inclined posture. The hydraulic pressure introduced into one chamber 10 a of the hinge cylinder 10 reaches the solenoid valve 33 at the same time.
[0038]
When the operation switch 35 attached to the knob 34 of the hinged fork operating lever 30 is pressed, the solenoid valve 33 is switched, and the same hydraulic pressure as that acting on the hinge cylinder 10 is introduced into the lock cylinder 22. The As a result, the lock pin 21 shown in FIGS. 2 and 3 protrudes and engages with any one of the plurality of lock grooves 14 formed in the side bar 13, and as a result, the carriage 5 is against the outer mast 3. It is mechanically locked so that it cannot move up and down.
[0039]
In this state, when the hinged fork operating lever 30 is further pushed forward, the hinged fork 8 further tilts forward according to the displacement of the operating lever 30, and the hinged fork 8 has a specific structure. A force that positively presses down is generated. At this time, the reaction force generated when the hinged fork 8 presses a specific structure downward is input from the carriage 5 to the outer mast 3 via the locking device 25 and finally the outer mast 3. The vehicle body 1 itself supporting the outer mast 3 bears a burden. This makes it possible for the first time to perform a downward push-down operation, which has been difficult with conventional hinged fork type forklifts.
[0040]
When the hinged fork operating lever 30 is pulled back, the hinged fork 8 is tilted backward, and when the operation switch 35 is pressed again, the lock device 25 is unlocked.
[0041]
Here, in the lock cylinder 22 for operating the lock pin 21 of the lock device 25, a part of the hydraulic pressure introduced into the hinge cylinder 10 when the hinged fork 8 is tilted forward is passed through the solenoid valve 33. Since the lock cylinder 22 is released to the drain side except when the hinged fork 8 is tilted forward, the operation switch 35 is not used except when the hinged fork 8 is tilted forward. Even if a pressing operation is performed, the locking device 25 does not perform a locking operation, and therefore does not become an obstacle during other cargo handling operations such as a lifting operation.
[Brief description of the drawings]
FIG. 1 is a side view showing an overall configuration of a forklift provided with a hinged fork.
FIG. 2 is a plan view of a main part of the mast device of the forklift shown in FIG.
3 is a view in the direction of arrow b in FIG. 2;
FIG. 4 is a hydraulic circuit diagram of a hinged fork and a locking device.
[Explanation of symbols]
2 ... Mast device 3 ... Outer mast 5 ... Carriage 8 ... Hinge fork 10 ... Hinge cylinder 13 ... Side bar 14 ... Lock groove (lock engagement part)
21 ... Lock pin 22 ... Lock cylinder (lock actuator)
25 ... Locking device 29 ... Control valve 30 ... Hinge fork operation lever 33 ... Solenoid valve 35 ... Operation switch

Claims (6)

An inner mast that guides and supports a carriage having a hinged fork so as to be movable up and down, and an outer mast that guides and supports the inner mast so that the inner mast can be lifted and lowered. Is a forklift mast device adapted to move up and down,
A mast device for a forklift equipped with a hinged fork, characterized in that a locking means for locking the carriage to an outer mast at an arbitrary position of its lifting stroke is provided. The forklift mast apparatus having a hinged fork according to claim 1, wherein the locking means is of an actuator drive. The locking means is
A plurality of lock engaging portions arranged along the vertical direction of the outer mast;
A lock pin that is provided on the carriage side and moves forward and backward by the operation of a lock actuator to engage and disengage one of the lock engaging portions, thereby controlling locking and unlocking;
The mast device of a forklift having a hinged fork according to claim 2, wherein 4. The hinged fork according to claim 3, wherein the locking means can be locked only when the hinged fork is tilted forward by operation of a hinged fork operating lever. Forklift mast equipment. The lock actuator of the locking means is configured with a hydraulic cylinder, and this hydraulic cylinder locks the lock pin using the hydraulic pressure introduced into one chamber of the hinge cylinder when the hinged fork is tilted forward. mast assembly for a forklift having a hinged fork according to claim 4, characterized in that adapted to. 6. The mast of a forklift with a hinged fork according to claim 5, wherein the locking means can be locked and unlocked by operating a switch attached to a hinged fork operating lever. apparatus.

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