JPH0756318Y2 - Forklift control equipment - Google Patents

Description

[Detailed description of the device]

[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 equipped with an attachment such as a roll clamp or a bail clamp.

[0002]

2. Description of the Related Art A forklift truck is an industrial vehicle for loading and unloading, which has a mast for raising and lowering loaded loads 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 and type of the cargo.
As one type of this attachment, there is a roll clamp which is useful when a cylindrical product, for example, a roll paper is held and lifted and transported.

FIG. 5 is an explanatory view conceptually showing a front portion of a forklift equipped with a roll clamp, that is, an elevating portion. As shown in the figure, the lift cylinder 1
Is fixed to the outer mast 2, and the inner mast 3 is moved up and down by using the outer mast 2 as a guide as the piston rod 1a expands and contracts. At this time, the outer mast 2 is fixed to the vehicle body (not shown).

The roll clamp 4 is a cylindrical product, such as a roll paper 33, composed of two clamp pieces whose base ends are rotatably supported as the piston rod of a clamp cylinder (not shown) expands and contracts. Is held, and the held state is released. The bracket 5 on which the roll clamp 4 is mounted is suspended on the chain 6. The chain 6 is suspended on a chain wheel 7 rotatably supported by the inner mast 3, and one end is fixed to the bracket 5 and the other end is fixed to the outer mast 2.

[0006] Thus, the roll clamp 4 which is the elevating part.
The bracket 5 not only moves up as the inner mast 3 moves up, but also moves relative to the inner mast 3 as the chain wheel 7 moves up relative to the fixed portion (outer mast 2). That is, the amount of ascent of the ascending / descending portion with respect to the ground surface 34 is a value obtained by adding the amount of ascending of the inner mast 3 to the amount of relative ascending of the ascending / descending portion with respect to the inner mast 3 of the ascending / descending portion.

With respect to the lowering of the elevating part, the same relationship as when ascending is established only by reversing the moving direction.

When lowering the roll paper 33 in the cargo handling using the forklift, the elevating part is lowered until the lower end surface of the roll paper 30 comes into contact with a predetermined unloading place, for example, the ground surface 34. After the state shown in the figure is reached, the roll clamp 4 is opened and the holding of the roll paper 33 is released.

[0009]

As described above, when the holding of the roll paper 33 is released, as shown in FIG. 5, after the lower end surface of the roll paper 33 comes into contact with the unloading place such as the ground surface 34, etc. There is no problem if the roll clamp 4 is opened and the holding of the roll paper 33 is released, but as shown in FIG.
If the roll clamp 4 is accidentally opened while the roll paper 33 is being lifted, an accident occurs in which the roll paper 33, which is the luggage at this time, falls.

In particular, in the electronically controlled forklifts that have rapidly become widespread in recent years, the working machine lever can be operated with a remarkably light operating force as compared with the mechanical forklift, and the roll can be operated by the operation of the working machine lever. Since the clamp 4 is opened and closed, the possibility of a fall accident due to an erroneous operation increases.

The electronically controlled forklift is
A forklift to which an embodiment of the present invention is applied, which will be described in detail later. A mechanical forklift is a speed control system that 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 speed up and down. Is adjusted.

The present invention has been made in view of the above-mentioned prior art, and an object of the present invention is to provide a control device for a forklift truck which can ensure a safe work without releasing the held state while holding and lifting a load.

[0013]

The structure of the present invention for achieving the above object is as follows.

Along with the expansion and contraction of the piston rod of the hydraulic cylinder for opening and closing, a cylindrical product is held from the outer peripheral surface thereof, and an attachment such as a roll clamp is provided for releasing the holding, and the expansion and contraction of the piston rod of the hydraulic cylinder for lifting and lowering. A control device for a forklift for lifting and lowering a load held by an attachment, which is arranged in a hydraulic line for supplying pressure oil of the lifting hydraulic cylinder and flows through the hydraulic line. Oil pressure detection means for detecting the pressure of pressure oil, real-time load detected based on the pressure of pressure oil detected by the oil pressure detection means during cargo handling, and no-load load that is the load that acts on the lifting hydraulic cylinder when empty And the set value that is set in advance based on the load of the cargo to be loaded, and when the applied load is larger than the set value. Attachment and having a controller for controlling so as to lock the driving of the opening and closing hydraulic cylinder so as not to open.

[0015]

According to the present invention having the above structure, when the load exceeds the set value, that is, when the load is held by the attachment and lifted, the drive of the opening / closing hydraulic cylinder is locked and the attachment opens. There is no such thing.

[0016]

Embodiments of the present invention will be described in detail below with reference to the drawings. The same parts as those in FIGS. 5 and 6 are designated by the same reference numerals.

FIG. 3 is a perspective view showing an example of a forklift truck to which this embodiment is applied. As shown in the figure, this forklift truck has a roll clamp 4 for holding a cylindrical product as an attachment. The lift cylinder 1 is fixed to the pair of left and right outer masts 2, and the pair of left and right inner masts 3 is moved up and down by using the outer mast 2 as a guide as the piston rod 1a expands and contracts. At this time, the outer mast 2 is fixed to the vehicle body 7 in front of the vehicle body 7. As a result, as the inner mast 3 moves up and down, the lifting unit including the bracket 5 suspended on the chain 6 (see FIGS. 5 and 6) and the roll clamp 4 that holds the load moves up and down.

The tilt cylinder 8 together with the outer mast 2 and the inner mast 3 moves up and down in the forward direction (opposite the vehicle body 7).
Side) and rearward (vehicle body 7 side). That is, in the case of unloading, in addition to tilting forward, when loading and transporting luggage, it tilts rearward to ensure good workability and safety.

In the clamp cylinder 9, the piston rod 9a expands and contracts to rotate the two clamp pieces 4c and 4d of the roll clamp 4 which rotate about the hinge portions 4a and 4b at the base end, respectively. The roll clamp 4 is opened and closed.

The working machine levers 10a, 10b, 10c are
The operator operates these to control the operations of the lift cylinder 1, the tilt cylinder 8 and the clamp cylinder 9 through the controller 11 and the electromagnetic proportional control valve 12, and together with the safety switch 13 for performing an emergency stop, It is stored in the tech box 14. The work machine levers 10e and 10d are provided in advance to cope with the case where various attachments are attached. The seat switch 15 is a switch that operates when an operator sits in the driver's seat 16 and outputs its output signal to the controller 11.

FIG. 4 is a block diagram showing an example of the control device for the forklift. In the figure, those parts which are the same as those corresponding parts in FIG. 3 are designated by the same reference numerals, and a overlapping description will be omitted.

As shown in FIG. 4, the working machine lever 10a,
10b and 10c are formed by potentiometers,
A lever operation signal S ₁ whose current value is proportional to the operation amount is sent to the controller 11. The controller 11 sends out a flow rate control signal S ₂ for adjusting the opening of the spool of the electromagnetic proportional control valve 12 based on the lever operation signal S ₁ . The solenoid proportional control valve 12 controls the flow rate of the pressure oil flowing through the hydraulic line 16 by moving the spool in proportion to the magnitude of the flow rate control signal S ₂ , thereby controlling the lift cylinder 1, the tilt cylinder 8 and the clamp cylinder. 9 operation speed, work equipment lever 1
The control is performed so as to correspond to the operation amount of 0a to 10c.

The hydraulic sensor 18 is arranged in the hydraulic line 17, and sends out a hydraulic signal S ₃ representing the pressure of the pressure oil in the hydraulic line 17. The controller 11 processes the hydraulic signal S ₃ to calculate the load applied to the lift cylinder 1, the tilt cylinder 8 and the clamp cylinder 9. Setting device 1
Reference numeral 9 is for setting a load, which is the load of the cargo to be handled, and supplying this data to the controller 11.

Further, the controller 11 includes a warning light 20.
When the starter switch 22 housed in the console box 21 is turned on, power is supplied from the battery 23 to operate, and when the safety switch 13 is operated and the seat switch 15 is not operated, the current of the flow rate control signal S ₂ Electromagnetic proportional control valve 1 with a value of zero
Control to close the spool of No. 2.

In the figure, 24 is a hydraulic pump and 25 is a hydraulic oil source. Further, the electromagnetic proportional control valve 12 and the hydraulic line 1
The hydraulic systems such as 7, the hydraulic sensor 18, the hydraulic pump 24, etc. are provided by the number corresponding to the number of the working machine levers 10a to 10e. This embodiment has at least three working machine levers 10a to 10c for lifting, tilting, and clamping in order to perform lifting, tilting, and clamping operations.
Three hydraulic systems are provided.

FIG. 1 is a block diagram showing a main part of this embodiment, that is, a control device in which a control system of the roll clamp 4 is extracted. In the figure, those parts which are the same as those corresponding parts in FIGS. 3 and 4 are designated by the same reference numerals, and a description thereof will be omitted.

As shown in FIG. 1, the lever operation signal S ₁ sent from the working machine lever 10c is supplied to the control amount extraction means 27 via the signal selection section 26. Control amount extraction means 26
Refers to the operation amount / control amount correspondence table 27, and the flow rate control signal S ₂ representing the control amount corresponding to the lever operation signal S _1.
Is sent. That is, the operation amount / control amount correspondence table 2
In 8, the amount of movement of the spool of the electromagnetic proportional control valve 12 corresponding to the amount of operation of the working machine lever 10c is stored in a one-to-one correspondence. The flow rate control signal S ₂ is supplied to the electromagnetic proportional control valve 12c via the control amount output means 29.

The signal selection section 26 is normally the work implement lever 1
When the lever operation signal S ₁ proportional to the operation amount of 0c is sent, but the mode detected based on the polarity of the lever operation signal S ₁ is the open mode of the roll clamp 4,
When the comparison unit 29 is sending the lock signal S ₄ ,
Regardless of the value of the lever operation signals S _1, to lock the clamp cylinder 9 to the current state of the current value of the lever operation signals S ₁ as zero.

The comparator unit 30 includes a set point signal S ₅ which is stored in the setting value storage unit 31, compares the applied load signal S ₆ for detecting the load load calculating unit 32, the value of the load weight signal S ₆ When the value exceeds the set value of the set value signal S _5, the lock signal S ₄ is sent. The set value storage unit 31 stores the roll clamp 4 and the bracket 5 (see FIG. 3) based on the hydraulic signal S ₃ sent by the hydraulic sensor 18a provided in the hydraulic line 17a of the hydraulic system of the lift cylinder 1 in an empty state. of calculating the load of only the lifting unit adds the data representing the live load that is set in the setting unit 19 determines the value of the setpoint signal S _5, is for storing the setting value signal S _5. The set value at this time is a value that reflects the state as shown in FIG. 6, that is, the state in which the roll paper 33 held by the roll clamp 4 is being lifted. The load calculation unit 32
The hydraulic pressure signal S sent by the hydraulic pressure sensor 18a during lifting and lowering of luggage
_The load weight is calculated based on ₃ and the calculated value is sent out as the load weight signal S ₆ .

According to the above control device, when the value of the load signal S ₆ in real time exceeds the value of the set value signal S ₅ , the operation of the clamp cylinder 9 is controlled to be locked. Therefore, the state as shown in FIG.
That is, when the roll paper 33 held by the roll clamp 4 is lifted from the ground surface 34, the roll clamp 4
The opening operation of the roll clamp 4 is allowed only when the value of the load signal S ₆ is equal to or less than the set value signal S ₅ , that is, when the roll paper 32 contacts the ground surface 33.

The series of operations described above can be represented by a flow chart as shown in FIG.

Although the roll clamp 4 is used as an attachment in the above embodiment, the kind of attachment is not particularly limited as long as it is an attachment (for example, a bale clamp) that carries out cargo by holding a load. .

[0033]

As described above in detail with reference to the embodiments, according to the present invention, the attachment cannot be opened when the luggage is held by the attachment and the luggage is lifted. It is possible to prevent the accident of dropping the car.

[Brief description of drawings]

FIG. 1 is a block diagram showing an extracted control system related to a roll clamp, which is a main part of a control device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment shown in FIG.

FIG. 3 is a perspective view showing a forklift truck to which an embodiment of the present invention is applied.

FIG. 4 is a block diagram showing an entire control device according to an embodiment of the present invention.

FIG. 5 is an explanatory view conceptually showing an ascending / descending portion of a forklift equipped with a roll clamp.

FIG. 6 is an explanatory view conceptually showing a state in which a load may be dropped when the roll clamp of the forklift including the roll clamp is opened.

[Explanation of symbols]

 1 Lift Cylinder 1a Piston Rod 4 Roll Clamp 5 Bracket 6 Chain 9 Clamp Cylinder 9a Piston Rod 11 Controller 17a Hydraulic Pipeline 18a Hydraulic Sensor 19 Setter 33 Roll Paper

Continued Front Page (72) Creator Toshiyuki Midorikawa 3000 Tana, Sagamihara-shi, Kanagawa M ・ E ・ I ・ Sagami Hightech Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A piston rod of a hydraulic cylinder for lifting and lowering, which has an attachment such as a roll clamp for holding and releasing the cylindrical product from the outer peripheral surface thereof as the piston rod of the hydraulic cylinder for opening and closing expands and contracts. Is a control device for a forklift designed to lift and lower a cargo held by an attachment accompanying expansion and contraction of the hydraulic cylinder, which is arranged in a hydraulic pipeline for supplying pressure oil of the lifting hydraulic cylinder. The hydraulic pressure detection means for detecting the pressure of the pressure oil flowing in the passage, the real-time load load detected based on the pressure of the pressure oil detected by the hydraulic pressure detection means at the time of loading and unloading, and the load acting on the lifting hydraulic cylinder. When the applied load is larger than the set value by comparing the unloaded load and the set value that is set in advance based on the load of the cargo that is scheduled to be loaded and unloaded. Is a controller for controlling the drive of the hydraulic cylinder for opening and closing so as not to open the attachment.