JPH0324320Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a dry-beat prevention device for a press machine.

Conventional technology A double-acting press machine is equipped with an inner slide and an outer slide, and the outer upper mold and lower mold provided on the outer slide press the sheet material, and then the inner upper mold provided on the inner slide presses the sheet material. The sheet material may be pressure-formed with the lower mold.

Problems that the invention aims to solve: The outer upper mold contacts the lower mold with a soft touch, but the inner upper mold contacts the lower mold suddenly, so if for some reason it is operated without sheet material, it will become empty. This causes impressions on the inner upper mold.

When the sheet material is pressure-formed with a mold that causes indentations in this way, the product is damaged and the appearance quality is deteriorated.

This also occurs on single-acting press machines.

Note that if there is no sheet material, you can stop the press machine, but if you do this, you can install multiple press machines side by side and perform continuous press work, or in transfer press machines, etc. This is not desirable because it interrupts work.

Means and operation for solving the problem The piston of the cylinder provided on the slide is connected to the connecting rod, and the piston and slide are lowered as one through oil sealed in the oil chamber of the cylinder, and a dry running prevention cylinder is created. and a solenoid valve that communicates the oil chamber of the cylinder with the oil chamber of the cylinder via first and second pilot check valves, and supplies air to the vacant chamber of the dry firing prevention cylinder; First and second pilot solenoid valves are provided to supply pilot pressure oil to the stop valve. By supplying pilot pressure oil to the pilot check valve, the pressure oil in the oil chamber of the cylinder flows into the oil chamber of the cylinder to prevent dry firing, which moves the piston relative to the slide and prevents dry firing. In addition to supplying air to the empty chamber of the dry firing prevention cylinder, the first pilot solenoid valve supplies pilot pressure oil to the first pilot check valve, so that the pressure oil in the oil chamber can be supplied to the oil chamber of the cylinder. This is what I did.

Embodiment A slide 3 is provided along an upright 2 of a press machine body 1 so as to be able to move up and down, and a connecting rod 6 pivotally connected to a rotating body 5 provided on a crown 4 is pivotally connected to a rod 7 provided on the slide 3. At the same time, a balance cylinder 8 is connected between the crown 4 and the slide 3, and the slide 3 is lifted upward by its air pressure.

A piston 10 of a cylinder 9 is connected to the rod 7, and an oil chamber 11 is formed below the piston 10. Overload protector oil (hereinafter simply referred to as oil) is sealed in the oil chamber 11. ,
The piston 10 is pushed up by the pressure of this oil, creating a gap H between the bottom wall 9a of the cylinder 9 and the piston 10, and the connecting rod 6 moves the slide 3 to a predetermined lower limit position.

The oil chamber 11 is connected to the discharge side of the hydraulic pump 15 through a first passage 14 having a check valve 12 and a first solenoid valve 13, and is connected to the discharge side of the hydraulic pump 15, and has first and second pilot check valves 16,1.
It is connected to a second path 18 with 7.

The discharge pressure oil of the hydraulic pump 15 is supplied to the first and second pilot check valves 16 and 17 by the first and second pilot solenoid valves 19 and 20, and the second passage 18 prevents dry stroke. Oil chamber 2 of cylinder 21
1a and the oil chamber 22a of the overload protector cylinder 22, the air from the air source 23 is supplied to the empty chamber 21b via the regulator 24 and the second solenoid valve 25, and the air from the air source 23 is supplied to the empty chamber 22b. is supplied via the regulator 26.

Next, the operation will be explained.

During normal press work, the first and second pilot solenoid valves 19 and 20 are in the drain position (OFF), the first and second pilot check valves 16 and 17 are similar to normal check valves, and the second solenoid valve 25 is in the communication position (ON), the air pressure from the air pressure source 23 is supplied to the empty chamber 21b, the oil in the oil chamber 21a is pressurized, and the second limit switch _LS2 is turned ON.

Because of this, the oil in the oil chamber 11 rises to the same pressure as the oil pressure in the oil chamber 22a of the overload protector cylinder 22, and the piston 10 moves into the oil chamber 1.
Slide 3 is held in the position shown by the pressure of oil in 1.
can be lowered to a predetermined lower limit position and pressurized.

Overload acts on slide 3 and oil chamber 11
When the pressure of the oil in the overload protector cylinder 22 exceeds the above pressure, the piston 22c of the overload protector cylinder 22 descends and a portion of the oil in the oil chamber 11 flows out into the oil chamber 22a, so the cylinder 10 descends and the connecting rod 6
moves downward relative to the slide 3 to prevent overload.

When it is detected by some means that the sheet material is not supplied, the second pilot solenoid valve 20 goes to the communication position (ON) and the second pilot check valve 1
7 is in communication and the second solenoid valve 25 is in the drain position (OFF), so when the slide 3 is lowered in this state, the oil in the oil chamber 11 flows into the oil chamber 21a, as shown in FIG. Since the piston 10 moves toward the bottom wall 9a of the cylinder 9 by an amount S, the lower limit position of the slide 3 becomes an upper position by an amount S, and dry firing can be prevented.

The first pilot solenoid valve 19, which receives the signal indicating that there is a sheet material in the above-mentioned state, is placed in the communication position (ON), and the first pilot check valve 16 is placed in the communication state.
The second solenoid valve 25 is set to the communication position (ON) to supply air pressure to the empty chamber 21b to push the piston 21c, and the oil in the oil chamber 21a is transferred from the second passage 18 to the oil chamber 11.
to bring the piston 10 into the state shown in FIG.

The above-mentioned sheet material presence/absence signal is output by detecting whether or not there is a sheet material in the press machine or processing step adjacent to this press machine or processing step, and the output timing is as shown in the table in Figure 3. become that way.

[Effect of idea]

Switch the solenoid valve 25 to prevent dry firing cylinder 21
The air in the empty chamber 21b is discharged to the atmosphere, and the second
The pilot pressure oil is supplied to the second pilot check valve 17 by switching the pilot solenoid valve 20 to open the oil chamber 11.
If oil is allowed to flow from the oil chamber 21a to the oil chamber 21a, as the piston 10 descends, the oil in the oil chamber 11 is supplied to the oil chamber 21a of the dry run prevention cylinder 21, and the piston 10 descends relative to the slide 3. Stove rod 6
The lower limit position of the slide 3 is upward, and in this state, the solenoid valve 25 is switched to supply air to the empty chamber 21b of the dry firing prevention cylinder 21, and the first pilot solenoid valve 19 is switched to prevent the first pilot back check. If the valve 16 allows oil to flow from the oil chamber 21a to the oil chamber 11, the oil in the oil chamber 21a of the dry run prevention cylinder 21 will be supplied to the oil chamber 11 of the cylinder 9, and the piston 10 will move into the slide 2. On the other hand, the lower limit position of the slide 3 by the connecting rod 6 is lower than that mentioned above.

Therefore, by switching the solenoid valve 25 and the first and second pilot solenoid valves 19 and 20, pressing can be carried out and blank punching can be prevented, so that blank punching can be prevented without stopping the press machine.

In addition, since the oil in the oil chamber 11 of the cylinder 9 is discharged to the oil chamber 21a of the dry firing prevention cylinder 21,
By changing the stroke of the dry firing prevention cylinder 21 and the cross-sectional area of the oil chamber, the oil chamber 11 of the cylinder 9 can be
Slide 3 of piston 10 by changing the amount of oil discharged inside.
The stroke to prevent blank firing can be adjusted as desired by changing the stroke for the stroke.

In addition, oil is sealed in the oil chamber 11 of the cylinder 9 and the oil chamber 21a of the dry firing prevention cylinder 21, and the volume of the oil chamber 21a of the dry firing prevention cylinder 21 is increased or decreased to keep the oil in the oil chamber 21a of the cylinder 9. or discharge the
Since the oil does not flow into the tank and oil can be quickly supplied into the oil chamber 11 of the cylinder 9, the response is excellent, and while the slide 3 is rising from the dry firing state. It is possible to return to the press working state.

Furthermore, the oil chamber 11 of the cylinder 9 and the oil chamber 21a of the dry striking prevention cylinder 21 communicate with each other through first and second pilot check valves 16, 17, and the oil chambers 11, 21a communicate with each other during normal press work. The slide 3 can be moved up and down accurately with a predetermined stroke without flowing.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall view, FIG. 2 is an explanatory view of the cylinder portion when preventing blank firing, and FIG. 3 is a table for explaining the operation. 1 is the press machine body, 3 is the slide, 6 is the connecting rod, 9 is the cylinder, 10 is the piston, and 11 is the oil chamber.

Claims (1)

[Claims for Utility Model Registration] A cylinder 9 equipped with a piston 10 is provided on a slide 3 that is movable up and down on the press machine body 1,
A connecting rod 6 is connected to the piston 10, and oil is sealed in the oil chamber 11 of the cylinder 9 to create a gap H between the piston 10 and the bottom wall 9a of the cylinder 9, and the connecting rod 6 slides. 3 to a predetermined lower limit position, there is provided a dry-stroke prevention cylinder 21 that pressurizes the oil in the oil chamber 21a by pushing the piston 21c with air supplied to the empty chamber 21b, and A solenoid valve 25 is provided which communicates the empty chamber 21b of the dry strike prevention cylinder 21 with the air source 23 and the atmosphere, and the oil chamber 11 of the cylinder 9 and the oil chamber 11 of the dry strike prevention cylinder 21 are connected to first and second pilot check valves. 1
first and second pilot solenoid valves 19 and 2 that communicate with each other through a passage 18 having pilot check valves 6 and 17 and supply pilot pressure oil to the first and second pilot check valves 16 and 17;
A blank punching prevention device for a press machine, characterized in that a zero is provided.