JPH0225477Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention has a muller wheel driven by a motor in a kneading tank, and is used for kneading sand and a binder. Regarding machines.

(Prior art) Conventionally, in the kneading machine, the load current value of the motor that drives the muller wheel changes in proportion to the increase in the degree of kneading of the kneaded sand. It has been proposed to automatically open the discharge port of the kneading tank to discharge kneaded sand having an appropriate degree of kneading when the ratio reaches a predetermined value (for example, Japanese Patent Publication No. 53-2505, Japanese Patent Publication No. 53-1982).
No. 17339).

By the way, in the above-mentioned conventional technology, the kneading tank is provided with only one discharge port, and the degree of kneading of the kneaded sand increases unnecessarily due to excessive supply of binder, etc., and the load current of the drive motor increases. Even when the amount of mixed sand exceeds a predetermined value, the discharge port is opened to discharge the defective mixed sand to the outside of the machine. Therefore, when the kneaded sand that is intermittently discharged one batch at a time from the kneading tank is transported to the next process by a conveying means such as a belt conveyor, both the normal kneaded sand and the defective kneaded sand are transported. In such cases, currently, an operator visually inspects or holds the kneaded sand while it is being transported, and removes only defective kneaded sand. In addition, if the binder is not supplied due to some accident or if the supply amount is insufficient, the degree of kneading of the mixed sand will not increase and the load current of the drive motor will not reach the predetermined value. The outlet of the kneading tank will not open unless this happens. As described above, in the conventional technology, part of the molding sand kneading work has been automated, but there are still parts that require manual labor, and complete labor savings have not been achieved.

(Purpose of the invention) The present invention has been made in view of the above-mentioned circumstances, and aims to provide a kneading machine that can completely save labor in kneading foundry sand.

(Structure of the invention) Hereinafter, the present invention will be explained in detail based on an example. Fig. 1 shows a kneading machine according to the invention, in which a kneading tank 1 having a cylindrical cross section revolves around a vertical axis 2. At the same time, a pair of muller wheels 4, 4 that rotate around horizontal shafts 3, 3 are arranged, and the vertical shaft 2 is rotationally driven by a motor 6 via a transmission mechanism 5. .

On the side wall of the kneading tank 1, a normal sand discharge port 7 is provided on the left side as viewed from the drawing, and a defective sand discharge port 8 is provided on the right side. , 11 are respectively attached to doors 12 and 13 which can be opened and closed. A belt conveyor 14 is disposed below the normal sand discharge port 7 to convey the kneaded sand to the next process. Further, a defective sand receiving box (not shown) is placed below the defective sand discharge port 8.

The motor 6 is electrically connected to a meter relay 15, and a solenoid valve 1 disposed in the middle of the air piping in each of the cylinders 9, 11.
6 and 17 are also electrically connected to the meter relay 15, and the meter relay 15 detects the load current of the motor 6 after a predetermined period of time has elapsed after the start of kneading, and also controls the electromagnetic valve based on the detected value. 1
It is designed to issue ON and OFF signals to 6 and 17.

(Function) In the kneading machine configured as described above, the normal sand discharge port 7 and the defective sand discharge port 8 are connected to the doors 12 and 1 by the extension operation of the piston rods of the cylinders 9 and 11.
3 and then drive the motor 6 to rotate the muller wheels 4, 4 in the kneading tank 1, and then feed foundry sand and binder into the kneading tank 1 from a feeder (not shown). do.

After a predetermined period of time has passed after the start of kneading, the current value of the motor 6 is within a predetermined range (for example, 85% of the rated current value).
% to 100%), a signal from the meter relay 15 causes the solenoid valve 1 on the normal sand discharge port 7 side to
6 is turned ON, the piston rod of cylinder 9 is shortened, and door 1, which had closed the normal sand discharge port 7, is closed.
2 opens, and the kneaded sand in the kneading tank 1 is discharged from the discharge port 7. Note that the discharged sand is conveyed to the next process by a belt conveyor 14. On the other hand, if the current value of the motor 6 is outside the predetermined range (for example, less than 85% or more than 100% of the rated current value), a signal from the meter relay 15 causes the electromagnetic Valve 17 is turned on,
The piston rod of the cylinder 11 is shortened, the door 13 that had closed the defective sand discharge port 8 is opened, and the kneaded sand in the kneading tank 1 is discharged from the discharge port 8. Note that the discharged sand is stored in a defective sand receiving box (not shown).

As the kneaded sand is discharged from the normal sand discharge port 7 or the defective sand discharge port 8, the current value of the motor 6 also decreases, but when the current value bottoms out, that is, the kneading tank 1 becomes empty. When a signal is emitted from the meter relay 15, the solenoid valves 16,
17 is turned off, the piston rods of the cylinders 9 and 11 are extended, and the doors 12 and 13 close the discharge ports 7 and 8.

Note that the meter relay 15 is connected to the solenoid valve 1.
The timing of issuing signals and the range of appropriate current values for 6 and 17 are determined based on the correlation between kneading time and current value in normal kneading work (see Figure 2), which has been determined in advance through experiments. .

The above-mentioned operations are regarded as one cycle, and the same cycle is repeated thereafter, whereby the foundry sand is continuously kneaded and intermittently discharged.

(Effect of the invention) As is clear from the above explanation, the present invention has a muller wheel driven by a motor in the kneading tank, and is used in a kneading machine for kneading foundry sand and a binder. A discharge port for normal sand and a discharge port for defective sand are provided in the tank separately, and the doors of both discharge ports can be opened and closed by cylinders, and the current value of the drive motor of the muller wheel can be detected by a meter relay. and electrically connect the meter relay to the solenoid valve of the cylinder, and after starting the kneading operation,
When the current value is within a predetermined range after a predetermined time has elapsed, the normal sand discharge port is opened by a signal from the meter relay, and when the current value is outside the predetermined range, the normal sand discharge port is opened. The discharge port for the defective sand is opened by a signal from a meter relay.

Therefore, according to the present invention, all of the kneaded sand in the kneading tank is discharged after a predetermined period of time has passed after the start of kneading, without distinguishing between normal sand and defective sand. It is discharged from the outlet. Therefore, even if the degree of kneading of the kneaded sand does not increase due to non-supply of binder, and therefore the load current of the muller wheel drive motor does not reach a predetermined value, the kneaded sand will not remain in the kneading tank. do not have. Furthermore, even when the mixed sand is conveyed to the next process by a belt conveyor or the like, only normal sand is conveyed, so there is no need to sort the sand midway through, making it possible to completely save labor in the mixing operation.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram of the kneading machine according to the present invention, and FIG. 2 is a graph showing the correlation between the current value of the muller wheel drive motor and the kneading time in the kneading machine. 1: Kneading tank, 4, 4: Muller wheel, 6: Motor, 7: Normal sand outlet, 8: Defective sand outlet,
9, 11: cylinder, 12, 13: door, 15: meter relay, 16, 17: solenoid valve.

Claims (1)

[Scope of utility model registration request] In a kneading machine having muller wheels 4, 4 driven by a motor 6 in a kneading tank 1, a normal sand discharge port 7 and a defective sand discharge port 8 are separately provided in the kneading tank 1, and both discharge ports are provided separately. Doors 12 and 13 which can be opened and closed by cylinders 9 and 11 are attached to the exits 7 and 8, respectively, and the motor 6 is connected to the meter relay 1.
5 and the meter relay 15
are electrically connected to the solenoid valves 16 and 17 of the cylinders 9 and 11, respectively.