JPS6045999B2 - Automatic control device for scrap pressure forming machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an automatic hoist for a scrap pressure forming machine for pressure forming scrap by operating a pressure plate using a hydraulic cylinder driven by a single hydraulic pump. Regarding the brightness device.

Model diagrams of conventional examples of automatic control devices for this type of scrap pressure molding machine are shown in FIGS. 1, 2, and 3.

1 is a pressure plate, 2 is a hydraulic cylinder, 3 is a piston rod,
4 is a side formwork, 5 is a gate formwork, and 6 is a pressurized space.

The number of hydraulic cylinders 2 is one, two, and three in FIGS. 1, 2, and 3, respectively. In the case of a two-cylinder or three-cylinder type, the conventional means is to operate all cylinders simultaneously.

In any case, a high/low pressure pump or a variable displacement pump is used to provide the capacity.

When the scrap density is low, low-pressure, large-capacity hydraulic pressure is supplied to the cylinder to move the pressure plate at high speed.

When the density of scrap becomes high, it is supplied to a high-pressure, small-capacity hydraulic cylinder and the pressure plate is moved at low speed and high pressure.

The piston pressure receiving area of each cylinder is S in FIG. 1, 512 in FIG. 2, and 513 in FIG. 3.

The amount of discharged oil required to move the pressure plate by a unit length is the same in all three cases. These three examples have the following problems.

Although electric motors have been effectively used when considering the use of high-low pressure pumps or variable displacement pumps, effective use of hydraulic pumps has not been considered.

In other words, when the density of scrap is low, the required thrust of the hydraulic cylinder is only a fraction of the maximum thrust in the process of opening the gate formwork and discharging the molded product after completion of a predetermined forming process, and in the process of pulling back the pressure plate. Therefore, a large amount of time is required for one processing, and the processing capacity per unit of time is small. An object of the present invention is to eliminate the loss of operating time of a hydraulic cylinder at a stage when the scrap density is low, thereby increasing throughput per unit time, and in eliminating such loss of operating time, In response to the nature of scrap materials, which have varying densities before pressurization, it is possible to automatically increase the pressurizing force when the scrap density reaches a predetermined value, thereby increasing the processing capacity per unit time. The purpose is to increase the number of people in the society.

The characteristic structure of the present invention for achieving the above object is as follows:
A plurality of hydraulic cylinders for pressing one pressure plate are connected to a discharge side flow path of one hydraulic pump, and some of the hydraulic cylinders are connected to the discharge side flow path. , a switching valve is provided for driving the pressure plate by selectively switching between an action direction that presses the pressure plate and a reaction direction that pulls back the pressure plate, and the switching valve is switched between the action direction and the reaction direction. Even in a state where the other hydraulic cylinders are in a non-input state and follow the above-mentioned part of the hydraulic cylinders, and a state where the switching valve is switched to the operating direction and the discharge side flow path is A control mechanism is provided for switching and controlling the operating state of the other hydraulic cylinder to a second state in which the other hydraulic cylinder is actuated in the operating direction when the internal pressure of the cylinder reaches a set value. .

In order to facilitate understanding of the above configuration, the configuration principle (concept) will be explained based on A, C, C, and H in FIG. 4 (note: D is not taken into consideration).

Although there are three hydraulic cylinders in this figure, this is a preferable example of the one or more cylinders mentioned in the summary, and is not limited to R3 cylinders. 10 is a main cylinder, and 11 is a sub cylinder.

12 is a pressure plate, 13 is a piston rod, 14 is a side formwork,
1:. 5 is gate formwork, 16 is scrap.

A black arrow indicates pressure oil supply, and a white arrow indicates no pressure oil supply (natural flow is possible). The operation is as follows (4) to (C
).

4(4) In the first state (a) (FIG. 4A), pressure oil is supplied only to the other cylinder 10 at a low pressure and in a large flow, and the pressure plate moves at high speed. Compared to conventional models, the number of cylinders is twice as fast. (B
) In the second state (b) (Fig. 4, opening and c), pressure oil is supplied to all cylinders 10 and 11.

Pressure oil moves from low pressure to high pressure, and from large flow to small flow. Particularly in the final stage of molding, the pressure oil reaches its maximum working pressure and the flow rate becomes its minimum. (C) In the third state (c) (FIG. 4(e)), the pressure oil supplied only to the other cylinder 10 is at a low pressure and a large flow rate, and the pressure plate moves at high speed.

Compared to conventional models, the number of cylinders is twice as fast. In this way, many parts of the pressure molding process are performed using the other cylinder (
In other words, it is performed only in some cylinders among a plurality of cylinders.

Therefore, the following effects can be obtained. In the operating process where the scrap density is low, which is the majority of the pressure forming process, only some of the hydraulic cylinders are driven, and the other hydraulic cylinders simply follow the movement without any input, so the pump power is By concentrating the pressure on only some of the hydraulic cylinders, it is possible to drive at high speed, and compared to the case where other hydraulic cylinders are driven at the same time, the wasted operating time of the hydraulic cylinders can be saved.

2 Moreover, when the scrap is pressurized and compressed to the appropriate density by some of the hydraulic cylinders, all the hydraulic cylinders automatically start to be driven accordingly, so the densities before pressurization are inherently different. To operate all hydraulic cylinders at the appropriate timing even though it is difficult to predict the timing to start operating all hydraulic cylinders based on the stroke of the hydraulic cylinder etc. in order to compress scrap that is a material. Therefore, the pressure stroke at low speed in which this full hydraulic cylinder is operated is kept within the appropriate minimum range, and the wastage of the hydraulic cylinder operating time of the horizontal layer is eliminated, allowing high-efficiency pressure forming. This gave me the advantage of being able to do the work.

Hereinafter, an embodiment of the present invention will be explained based on FIG. 5 while referring to all of FIG. 4 including FIG. 4-2.

21 is an electric motor, 22 is a variable displacement pump, 23 is a pressure switch, 24 is a pressure gauge with a microswitch type contact, 25 is a relief valve, 26, 27, 28 are solenoid valves, 29 is a prefill valve, 30 is a pilot circuit, 3
1 is a hydraulic cylinder of the gate formwork 15.

The solenoid pulp 26 is a switching valve for operating the main hydraulic cylinder 10 by selectively switching the action direction to press the pressure plate 12 or the reaction direction to pull back the pressure plate 12. It consists of
Further, the pressure switch 23, the solenoid valve 27,
The pre-fill valve 29 and the pilot circuit 30 cause the auxiliary hydraulic cylinders 11, 11 to be connected to the main hydraulic cylinder regardless of whether the solenoid valve 26 is switched to the acting direction or the reaction direction. 10 is not applied, and the first state is the following state where the solenoid valve 26 is switched to the operating direction, and the pressure switch 23 is in the state where the internal pressure is higher than the setting in the pump discharge side flow path. A control mechanism is configured to control the secondary hydraulic cylinders 11, 11 to be switched to a second state in which they are driven when detected. The operation of the device in this example is as follows. (1) After inputting scrap, the solenoid valve 26 is switched automatically or by manual command to extend the central main cylinder 10.

The valve 27 is closed = so that the left and right sub-cylinders 11,1
No pressure oil is sent to 1. However, the sub cylinder 11,1
Since the piston rod 1 is connected to the pressure plate 12, as the pressure plate 12 is moved by the main cylinder 10, the sub cylinders 11, 11 are also extended. At this time, oil naturally flows in from one end of the sub-cylinders 11, 11 and naturally flows out from the other end. The pressure plate 12 gradually crushes the scrap 16. See Figure 4a. (2) As the crushing of the scrap 16 progresses, the reaction force increases and the pressure within the hydraulic system increases.

As a result, when the pressure switch 23 is switched, the solenoid valve 27 is switched, and the sub cylinders 11, 11 communicate with the pump 22. In other words, the pressure oil is in three cylinders 1
0, 11, 11. Therefore, while the moving speed of the pressure plate 12 decreases, the pressing force increases. This results in a strong crushing action on the scrap 16. See Figure 4, mouth and c. () The pressure in the hydraulic system increases more and more, and as a result, the contact point of the pressure gauge 24 becomes 0N.

Then, the solenoid valve 28 switches and the cylinder 31,
31 is extended and the gate formwork 15 is opened. As a result, the scrap 16 pressure-formed into a predetermined size and shape is placed on the pressure plate 1.
It is paid out by 2. Immediately after the gate formwork 15 is opened, the pressure in the hydraulic system drops, which causes the pressure switch 23 to switch. The solenoid valve 27 returns to close and pressure oil is supplied only to the main cylinder 10. That is, payout is performed at high speed. See Figure 4-2. 4) Pressure plate 1
2 turns on the limit switch 32, the solenoid valve 26 is switched and the pressure oil supply to the main cylinder 10 is reversed.

That is, the pressure plate 12 returns to its original position. This movement is fast. During this pullback, the sub cylinders 11, 11
Although no pressure oil is sent to the sub-cylinders 11, 11 are contracted following the movement of the pressure plate 12. At this time, oil naturally flows out from one end of the sub-cylinders 11, 11 and naturally flows in from the other end. To allow this flow, prefill valve 2
There is a pilot circuit 30 for opening 9. The pressure drop in the hydraulic system causes the contact of the pressure gauge 24 to return, switching the valve 28 and closing the gate formwork 15. See Figure 4, E. Brief Explanation of Threshold Surfaces FIGS. 1, 2, and 3 are flat views showing conventional examples.

FIGS. 4A to 4E are plan views showing sequential operations according to the present invention. Figure 5 is a hydraulic river course map. 10,11
...Hydraulic cylinder, 12... Pressure cylinder.

Claims (1)

[Claims] 1 A plurality of hydraulic cylinders 10 and 11 for pressing one pressure plate 12 are connected to a discharge side flow path of one hydraulic pump 22, and the hydraulic cylinders 10 and 11 are connected to the discharge side flow path. Some of the hydraulic cylinders 1
0, the direction of action of pressing the pressure plate 12, and the pressure plate 1.
A switching valve 26 is provided to selectively switch the drive direction to the reaction direction that pulls back the hydraulic cylinder 2, and even when the switching valve 26 is switched to either the action direction or the reaction direction, the other hydraulic cylinder 11 can be driven. A first state in which some of the hydraulic cylinders 10 follow the state with no input, and a state in which the switching valve 26 is switched to the operating direction, and the internal pressure in the discharge side flow path reaches a set value. Scrap pressurization is provided with a control mechanism 23, 27, 29, 30 that switches and controls the operating state of the other hydraulic cylinder 11 to a second state in which the other hydraulic cylinder 11 is driven and operated in the operating direction when the other hydraulic cylinder 11 is operated. Automatic control device for molding machines.