JPH0756317Y2 - 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 of paper 32, 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 33 is a value obtained by adding the amount of ascending of the inner mast 3 to the relative amount of ascending / descending of the ascending / descending portion with respect to the inner mast 3 of the chain 6.

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

When the roll paper 32 is unloaded 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 33. After the state shown is reached, the roll clamp 4 is opened and the holding of the roll paper 32 is released.

[0009]

As described above, when the holding of the roll paper 32 is released, as shown in FIG. 5, the lowering part of the elevating part is lowered immediately after the lower end surface of the roll paper 32 contacts the ground surface 33. Is stopped, and there is no problem as long as the chain 6 supports the lifting portion, that is, the weight of the roll clamp 4 and the bracket 5, but as shown in FIG. When the roll clamp 4 and the bracket 5 are in a loose state, the weight of the roll clamp 4 and the bracket 5 is supported on the ground surface 32 via the roll paper 32 held by the roll clamp 4.

Therefore, when the roll clamp 4 is opened in the state shown in FIG. 6 and the holding of the roll paper 32 is released, the roll clamp 4 drops together with the bracket 5 by the looseness of the chain 6. As a result, the roll clamp 4 rubs the surface of the roll paper 30 and causes an accident.

In view of the above-mentioned prior art, the present invention provides a forklift control device that can perform good unloading work without damaging the load in cargo handling using a forklift equipped with an attachment for holding the load such as a roll clamp. The purpose is to provide.

[0012]

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 to release the holding, and the expansion and contraction of the piston rod of the hydraulic cylinder for lifting and lowering. A forklift control device for lifting and lowering a bracket suspended on a chain, and lifting and lowering a cargo held by an attachment mounted on the bracket, for supplying pressure oil from the lifting hydraulic cylinder. A hydraulic pressure detection unit that is installed in the hydraulic pressure line to detect the pressure of the pressure oil flowing through this hydraulic pressure line, a real-time load load detected based on the pressure of the pressure oil detected by the hydraulic pressure detection unit during cargo handling, and an empty load. Sometimes, compare it with a preset value that is smaller than the unloaded load that is the load that acts on the lifting hydraulic cylinder. And having a controller for controlling so as to lock the driving of the opening and closing hydraulic cylinder so the attachment does not open when the applied load is less than a set value.

[0014]

According to the present invention having the above-mentioned structure, when the applied load is less than the set value, that is, when the lifting parts such as the attachment and the bracket are lowered too much and the chain may be loosened, the opening / closing hydraulic pressure is applied. The cylinder drive is locked and the attachment will not open.

[0015]

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 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 moves forward and backward along with the outer mast 2 and the inner mast 3 (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.

The clamp cylinder 9 rotates the two clamp pieces 4c and 4d of the roll clamp 4 which rotates about the hinge portions 4a and 4b at the base end by the expansion and contraction of the piston rod 9a. The roll clamp 4 is opened and closed.

The working machine levers 10a, 10b and 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 pressure sensor 18 is arranged in the hydraulic pressure line 17, and outputs a hydraulic pressure signal S ₃ representing the pressure of the pressure oil in the hydraulic pressure 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.

Further, the controller 11 includes a warning light 19
When the starter switch 21 housed in the console box 20 is turned on, the battery 22 supplies electric power to operate the safety switch 13, 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 is supplied. Current proportional control valve 1 with zero value
Control to close the spool of No. 2.

In the figure, 23 is a hydraulic pump and 24 is a hydraulic oil source. Further, the electromagnetic proportional control valve 12 and the hydraulic line 1
7, hydraulic systems such as the hydraulic sensor 18, the hydraulic pump 23, etc. are provided in 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 extracting means 26 via the signal selecting section 25. 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 7, a moving amount of the spool of the electromagnetic proportional control valve 12 corresponding to an operating amount 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 28.

The signal selection section 25 is normally the operation 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 has sent a locking 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 comparison unit 29 compares the set value signal S ₅ stored in the set value calculation / storage unit 30 with the load load signal S ₆ detected by the load load calculation unit 31, and the load load signal S
_When the value of ₆ becomes less than the set value of the set value signal S ₅ , the lock signal S ₄ is sent out. The set value calculation / storage unit 30 uses 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 to output the roll clamp 4 and the bracket 5 (see FIG. 3). )
For calculating the load of only the ascending / descending part, multiplying the calculated value by a predetermined coefficient to select a set value that is slightly smaller than the calculated value, and storing it as a set value signal S ₅ representing this set value. Is. This set value is in the state as shown in FIG. 6, that is, the roll paper 32 held by the roll clamp 4.
Is applied to the ground surface 33, and the load calculation unit 31 adjusts the value so that the chain 6 has a loosened state.
The load load is calculated in real time on the basis of the hydraulic pressure signal S ₃ sent from the hydraulic pressure sensor 18a when the load is moved up and down, and the calculated value is sent out as the load load signal S ₆ .

According to the above control device, when the value of the load signal S ₆ in real time becomes less than the value of the set value signal S ₅ , the operation of the clamp cylinder 9 is controlled to be locked. Therefore, the roll paper 32 held by the roll clamp 4 is in the state as shown in FIG.
3 and the chain 6 is loosened, the opening operation of the roll clamp 4 is locked and the load load signal S
Value of ₆ only if it exceeds the set value signal S _5, i.e. the weight of the roll clamp 4 and the bracket 5 only when the chain 6 is supported, opening operation of the roll clamp 4 is allowed.

The above series of operations can be represented by a flowchart 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. .

[0032]

As described above in detail with reference to the embodiments, according to the present invention, the attachment is opened only when the chain is supporting the weight of the lifting portion to release the held load. Therefore, it is possible to perform good cargo handling work without damaging the cargo with the attachment accompanying this opening.

[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 there is a risk of damage to luggage 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 32 Roll Paper

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Midorikawa 3000, Tana, Sagamihara-shi, Kanagawa M / E / I Sagami High Tech Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A piston rod for 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 that is designed to raise and lower a bracket suspended on a chain in accordance with expansion and contraction of the chain, and to raise and lower a cargo held by an attachment attached to the bracket, which supplies pressure oil from the lifting hydraulic cylinder. For detecting the pressure of the pressure oil flowing through this hydraulic pipeline, and the real-time load detected based on the pressure of the pressure oil detected by the hydraulic pressure detection means during cargo handling, Compare with a preset value that is smaller than the no-load load, which is the load that acts on the lifting hydraulic cylinder when empty. The control device for a forklift characterized in that it comprises a controller for controlling so as to lock the driving of the opening and closing hydraulic cylinder so the attachment does not open when the applied load is less than a set value.