JPH05238697A - Forklift control device - Google Patents

Abstract

PURPOSE:To provide a forklift control device capable of inhibiting the release of the clamping state in principle in the case of a load being lifted while being clamped by attachments but releasing the clamping state even in the above- mentioned case when it is necessary as in the case of unloading paper rolls in the laterally loaded state, for instance. CONSTITUTION:Laden load actually acting upon a lift cylinder is detected on the basis of the output signal of an oil pressure sensor 21, and this laden load is compared with the set value based on unladen load at the unloaded time so as to detect the state of a load being lifted while being clamped by clamp pieces 1c, 1d. When this state is detected and that a microswitch 27 for indicating the horizontally held state of the load clamped by the clamp pieces 1c, 1d by its 'on' state is in the 'off' state, the opening operation of the clamp piece 1c by a clamp cylinder 8 is locked, whereas the opening operation of the clamp piece 1c can be always performed while the microswitch 27 is in the 'on' state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forklift control device, and is particularly useful when applied to a forklift having an attachment such as a rotary roll clamp that holds and rotates a load.

[0002]

2. Description of the Related Art A forklift is an industrial vehicle for loading and unloading, which is provided with a mast for moving a loaded load up and down in front of a vehicle body so that it can be moved from place to place.

The forklift is provided with various attachments so that a good cargo handling work can be performed on each cargo depending on the shape, type, etc. of the cargo.
As one type of this attachment, there is a rotary roll clamp useful for holding a cylindrical product, for example, a roll paper and rotating the roll paper so that the axial direction of the roll paper is horizontal to perform a predetermined cargo handling work.

FIG. 4 is a perspective view showing an electronically controlled forklift having a rotary roll clamp. This electronic forklift is a work machine lever called a joystick lever that is operated to process an electric signal sent from the joystick lever by a CPU, and an electromagnetic signal generated by a control signal sent from the CPU. It is configured to control the drive of the control valve to drive each hydraulic cylinder, and by operating the joystick lever, it is possible to perform predetermined work with a significantly lighter operating force compared to the conventional mechanical forklift. It has the feature that it can. A mechanical forklift, on the other hand, transmits the operation amount of the operating lever to a control valve via a mechanical link mechanism, and controls the opening of this control valve to control the amount of oil to control each hydraulic cylinder. It is configured to drive.

As shown in FIG. 4, this forklift has a rotary roll clamp 1 as an attachment for holding a cylindrical product. A lift cylinder 2, which is a lifting hydraulic cylinder, includes a pair of left and right outer masts 3.
Fixed to the left and right inner masts 4 by using the outer mast 3 as a guide as the piston rod 2a expands and contracts.
Is designed to go up and down. At this time, the outer mast 3 is fixed to the vehicle body 5 in front of the vehicle body 5. As a result, as the inner mast 4 moves up and down, the inner mast 4 is suspended on a chain (not shown), and the elevating part including the rotary roll clamp 1 and the bracket 6 moves up and down.

The tilt cylinder 7 moves forward and backward together with the outer mast 3 and the inner mast 4 (anti-vehicle body 5).
Side) and rearward (vehicle body 5 side). That is, in the case of unloading, it tilts forward, and in the case of loading and carrying a load, it tilts rearward to maintain good workability and safety.

The clamp cylinder 8, which is an opening / closing hydraulic cylinder, rotates the clamp piece 1c about the hinge portion 1a at the base end as the center of rotation due to expansion and contraction of the piston rod 8a. As a result, it is possible to hold the load between the clamp piece 1d and the clamp piece 1c, which are formed to be rotatable about the hinge portion 1b at the base end, and to release the held state. Configured.

The rotary roll clamp 1 also has a rotator (not shown) rotatably supported on the bracket 6 on its vertical surface so that the clamped pieces 1c and 1d can rotate the held load. Is configured. This rotator rotates using an oil motor (not shown), which is a rotation drive means, as a drive source.

Joystick levers 9a, 9b, 9c,
9d controls the operations of the lift cylinder 2, the tilt cylinder 7, the clamp cylinder 8 and the oil motor through the controller 10 and the electromagnetic proportional control valve when the operator operates them. It is arranged in the joystick box 12.

Thus, for example, when handling roll paper,
In the state in which the axial direction is vertical, that is, from the outer peripheral surface of the roll paper in the vertically stacked state, as shown in FIG.
The roll paper is clamped and lifted by c and 1d, the rotator is rotated by 90 °, and the roll paper is conveyed to a predetermined position while keeping the axial direction of the roll paper horizontal, and the roll paper is unloaded. It is possible to satisfactorily perform a work in which a truck bed or the like has a horizontal axial direction, that is, a horizontally stacked state.

[0011]

In the forklift truck having the rotary roll clamp 1 as described above, the clamp piece 1c is accidentally opened in a state in which vertically stacked roll papers are held by being clamped by the clamp pieces 1c and 1d. in case of,
At this time, the roll paper, which is the baggage, falls. In order to avoid such a situation, the clamp piece 1
It is only necessary to lock the drive of the clamp cylinder 8 in the state where the load is held by c and 1d and lifted, but in this case, the axial direction of the roll paper is made horizontal and the unloading work is performed. A new problem arises in that the clamp pieces 1c cannot be opened even when trying to stack roll paper horizontally.

In view of the above-mentioned prior art, the present invention basically prohibits the release of the sandwiched state when the attachment is sandwiched and lifted, and for example, unloading the roll paper in a horizontal stacking state. It is an object of the present invention to provide a control device for a forklift that can release the held state even in the above-described case when necessary.

[0013]

The structure of the present invention which achieves the above object is to hold a cylindrical product from the outer peripheral surface thereof as the piston rod of a hydraulic cylinder for opening and closing expands and contracts, and to release the holding. On the other hand, it has a rotator that rotates in a vertical plane by the rotation driving means, and has an attachment such as a rotary roll clamp that is configured so that the holding part can rotate integrally with the rotator, and further for raising and lowering. A forklift control device configured to raise and lower a load held by an attachment as the piston rod of the hydraulic cylinder expands and contracts together with a lifting unit including this attachment, and detects a load applied to the lifting hydraulic cylinder. The load detection means, the position detection means for detecting that the rotator has rotated and reached a predetermined position, and the load detection means The load that is the real-time load that is detected when the load is compared with the set value that is set based on the no-load that is the weight of the lifting unit that is detected by the load detection means when the load is empty. When the set value is exceeded and the position detection means does not detect that the rotator has reached the predetermined position, the control means for controlling the drive of the opening / closing hydraulic cylinder so as to prevent the attachment from opening. And having.

[0014]

According to the present invention having the above-mentioned structure, by processing the output signal of the load detecting means, in principle, when it is detected that the load is being held while being lifted, the opening / closing cylinder is in principle opened. Although the drive of the rotator is locked, even if it is detected that the rotator is in the specified position (for example, the position that holds the roll paper so that its axial direction is horizontal), the opening and closing The holding cylinder can be released by driving the operating cylinder.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a control system according to this embodiment, and FIG. 2 is a hydraulic circuit diagram showing the hydraulic system. As shown in both figures, the joystick levers 9c and 9d are
The clamp cylinder 8 and the oil motor 13 are driven by tilting each of these levers back and forth (right and left in the figure), and the analog signals of a level corresponding to the operation amount (tilt amount) are respectively transmitted. I am doing it. Each analog signal is converted into a digital signal by the A / D converter 14 and supplied to the CPU 15. CPU15 is A /
The digital signal which is the output signal of the D converter 14 is processed, and any one of the electromagnetic control valves 17 and 18 or the electromagnetic control valve 19 and 18 is processed via the electromagnetic valve drive circuit 16.
Any one of 20 is operated. Electromagnetic control valve 17, 18
Is for controlling the opening and closing of the holding part 1c, the electromagnetic control valve 19,
Reference numeral 20 controls the rotation of the oil motor 13 to the right and left.

The hydraulic pressure sensor 21, which is a load detecting means, is interposed in the pipeline for supplying the pressure oil for extending the piston rod of the lift cylinder, that is, in the pipeline for supplying the pressure oil on which the load is applied. An analog signal representing the hydraulic pressure of this pipeline is supplied to the CPU 15 via the A / D converter 14. The CPU 15 processes the signal representing the hydraulic pressure to calculate the real-time load applied to the lift cylinder.

The rotator 23 is constructed so as to integrally rotate the clamp cylinder 8 and the clamp pieces 1c and 1d, and the rotating power at this time is rotated by the oil motor 13 via the worm 24, the worm gear 25 and the pinion 26. 23. That is, the worm gear 2
5 and the pinion 26 mesh with a ring gear (not shown) of the rotator 23. A convex portion 23a is formed on the peripheral surface of the rotator 23, and the convex portion 2 is formed on the micro switch 27 which is the position detecting means in accordance with the rotation of the rotator 23.
3a is abutted to operate the micro switch 27. That is, the micro switch 27
Is a rotator so that the convex portion 23a comes into contact with the rotator 23 at a position rotated 90 ° counterclockwise in the drawing from the origin (the point where the rotary roll clamp 1 is held in the state shown in FIG. 4) to operate. It is arranged in the vicinity of 23. By the way, the position where the micro switch 27 operates in this way is such that the clamp piece 1c is on the upper side,
1d and the clamp cylinder 8 rotate, and the clamp piece 1
e, 1d is a position where, for example, a roll paper is held so that its axial direction is horizontal.

The selection switches 28 and 29 are switches for selecting whether to select the upper / lower limit control mode and the upper limit control mode. Status signals representing respective states (ON / OFF states) are supplied via the switch input interface 30. It is supplied to the CPU 15. The upper and lower limit control modes referred to here are the load that is actually acting on the lift cylinder,
The upper limit setting value and the lower limit setting value set based on the no-load load are compared, and when the load load> the upper limit setting value and the load load <the lower limit setting value, the driving of the clamp cylinder 8 is controlled to be locked. The former is a clamp piece 1c,
1d means that the load is being held while being lifted, and the latter means that the lift cylinder is in a state where no unloaded load is acting. The latter situation occurs when the chain that suspends the lifting unit loosens and the load of the lifting unit is supported by the ground or the like. When the held state of the load is released in the state where the chain is loose in this way, there is a possibility that the lifting portion may drop at the origin position of the rotator 23 and the load may be damaged by the clamp pieces 1c and 1d. It is the lower limit control mode of the upper and lower limit control modes that effectively prevents the occurrence of such a situation. The upper limit control mode is a mode in which the above-described control is performed by detecting only when the load is held by the clamp pieces 1c and 1d and lifted.

The controller 31 has the CPU 15 as a main constituent element, and the A / D converter 14, the solenoid valve drive circuit 16, the switch input interface 30, a clock circuit 32, a RAM 33, a ROM 34, and an external battery 35 as a power source. It is composed of a circuit 36 and the like.

ROM 34 in the controller 31
The control currents corresponding to the operation amounts of the joystick levers 9c and 9d are stored in the two correspondingly. Further, the electromagnetic control valves 17 to 20 adjust the flow rate of the pressure oil according to the control current. Thus, normally Joystick lever 9
The amount of oil supplied to the clamp cylinder 8 and the oil motor 13 is controlled according to the operation amounts of c and 9d, but in some cases, the joystick lever 9c is processed by the CPU 15.
The control current supplied to the electromagnetic control valve 17 is forcibly set to zero irrespective of the operation amount of (1) to lock the opening operation of the clamp piece 1c.

In this embodiment, when the selection switch 28 is in the ON state and the upper / lower limit control mode is selected, the micro switch 27 is in the OFF state and the rotator 2 is turned on.
It is detected that the rotation position of 3 is not the predetermined position, and the load load> the upper limit set value or the load load <
When the condition of the lower limit setting value is satisfied, the clamp piece 1c
Opening operation is locked.

On the other hand, when the selection switch 29 is ON and the upper limit control mode is selected, the micro switch 27 is OFF and it is detected that the rotating position of the rotator 23 is not the predetermined position. Moreover, when the condition of applied load> upper limit set value is satisfied, the opening operation of the clamp piece 1c is locked. Further, when the micro switch 27 is in the ON state and it is detected that the rotating position of the rotator 23 is at the predetermined position, the opening operation of the clamp piece 1c is not locked.

The rotary roll clamp consisting of the clamp pieces 1c and 1d, the clamp cylinder 8 and the rotator 23 ascends and descends integrally with the elevating part as the lift cylinder is driven, so that it is wound around the hose reels 37 and 38. The pressure oil is supplied through the flexible hoses 39 and 40.

FIG. 3 is a flow chart of processing in the CPU 15. As shown in the figure, it is determined whether or not the clamp cylinder 8 is in the open mode based on the output signal of the joystick lever 9c (see the determination block 41), and the states of the selection switches 28 and 29 are detected in the open mode. Thus, it is determined whether the upper / lower limit control mode or the upper limit control mode is selected (see determination blocks 42 and 43). If any one of these modes is selected, the micro switch 27 is further selected. The rotator 23 detects the state of
It is determined whether or not it is at the predetermined position rotated by 0 ° (see the determination block 44).

If the rotator 23 is not in place,
When the relationship of load load> upper limit set value is established (see decision block 45), or when the relationship of load load <lower limit set value is established in the upper / lower limit control mode (see decision blocks 46 and 47). Sets the control current supplied to the electromagnetic control valve 17 to zero (see processing blocks 48, 49 and 50).

The decision block 41 has detected that it is in the open mode, and the decision blocks 42, 4 are
As a result of the determinations in Steps 3 and 44, when it is detected that the mode is not the upper / lower limit control mode or the upper limit control mode, and when the state in which the rotator 23 is rotated 90 ° from the origin is detected, and the determination is made. When it is detected that the block is in the closed mode, a control current corresponding to the operation amount of the joystick lever 9c is calculated, and the control current obtained as a result is supplied to the electromagnetic control valves 17 and 18 ( See processing blocks 50, 51, 52, 53). In this case, pressure oil according to the control current flows into the clamp cylinder 8 to open and close the clamp piece 1c.

Thus, according to the present embodiment, when the clamp piece 1c opens, there is a possibility of causing inconvenience, that is, when the load is held while being lifted, and when the chain is loosened and the lift cylinder is unloaded. When no load is applied, the opening operation of the clamp piece 1c can be locked. On the other hand, if the clamp piece 1c does not open even when the luggage is being lifted while being held, inconvenience may occur, that is, in the unloading work in which the cylindrical luggage such as roll paper is placed in a horizontal stacking state. In this case, the opening operation of the clamp piece 1c can be performed.

[0029]

According to the present invention as specifically described in connection with the above embodiments, not only can accidents that accidentally drop luggage during cargo handling be prevented, but also for the convenience of unloading work. When it is necessary to cancel the holding state of the luggage, this state can be detected and the opening operation can be performed with priority over all other conditions, and safety and workability can be maintained at the same time. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of the embodiment.

FIG. 3 is a flow chart showing an operation of the embodiment.

FIG. 4 is a perspective view showing a forklift having a rotary roll clamp.

[Explanation of symbols]

 1 Rotating Roll Clamp 1c, 1d Clamp Piece 2 Lift Cylinder 2a Piston Rod 8 Clamp Cylinder 8a Piston Rod 13 Oil Motor 21 Oil Pressure Sensor 23 Rotator 27 Micro Switch 31 Controller

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Matsuda 3000 Tana, Sagamihara-shi, Kanagawa Mitsubishi Heavy Industries, Ltd. Sagamihara Works (72) Inventor Toshiyuki Midorikawa 3000, Tana, Sagamihara, Kanagawa Eye Sagami High-Tech Co., Ltd. (72) Inventor Tsuruji Kitabayashi 3000 Tana, Sagamihara-shi, Kanagawa M-E-I Sagami Hi-Tech Co., Ltd.

Claims (1)

[Claims] 1. A holding means for holding a cylindrical product from its outer peripheral surface as the piston rod of an opening / closing hydraulic cylinder expands and contracts, and holding the holding portion to release the holding, while rotating in a vertical plane by a rotation drive means. A load that has a rotator and an attachment such as a rotating roll clamp that is configured so that the holding part can rotate integrally with the rotator, and that is held by the attachment as the piston rod of the lifting hydraulic cylinder expands and contracts. Is a control device for a forklift configured to move up and down together with an elevating part including this attachment, wherein load detecting means for detecting a load applied to an elevating hydraulic cylinder and a rotator rotate to reach a predetermined position. The position detection means that detects that the load has been detected and the load that is the real-time load actually detected by the load detection means. The load and the set value set based on the no-load load, which is the own weight of the lifting unit detected by the load detection means when the load is empty, are compared, and if the load exceeds the set value and the rotator A forklift control device, comprising: a control unit that controls to lock the drive of the opening / closing hydraulic cylinder so that the attachment does not open when the position detection unit does not detect that the predetermined position has been reached. ..