JPH0225537Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a dictation device.

Conventional Structure and Problems Conventionally, in a single-action press, for example, when squeezing a cylindrical container, wrinkles are prevented from forming on the peripheral edge of the blank. That is, as shown in FIG. 1, the punch 1 is fixed to a bolster 3 via a punch holder 2, and a pressure ring 5 for supporting the peripheral edge of the blank 4 is provided on the outside of the punch 1. The tension ring 5 is supported by a pressure pad 8 of a dictation 7 via a pressure pin 6, and the dictation 7 is always subjected to an upward force by air pressure. For example, the dictation 7 is provided with a pneumatic cylinder. In this configuration, as shown in FIG. 2, when the slide 9 descends, the peripheral edge of the blank 4 is pressed and wrinkled by the die 10 and the pressure ring 5, and the slide 9 further descends. Then, the blank 4 will be squeezed by the punch 1. By the way, conventionally, the above-mentioned wrinkle pressing force is constant during the drawing process, so it depends on the material of the blank,
Depending on the thickness and the amount of squeezing, wrinkles may not be suppressed well, which may have an adverse effect on the product.

OBJECT OF THE INVENTION It is an object of the present invention to provide a dictation device that can eliminate the above-mentioned conventional drawbacks.

Structure of the Invention In order to achieve the above object, the die cutting device of the present invention includes a pressure pad provided with a pressure ring on the upper surface to hold the peripheral edge of the blank between it and the die, and a pneumatic cylinder that urges the pressure pad upward. In the dictation device, a hydraulic cylinder is provided which urges the pressure pad in a direction that reduces the urging force of the pneumatic cylinder, and a plurality of switching valves and relief valves are respectively provided in the hydraulic circuit of the hydraulic cylinder to reduce the hydraulic pressure. It is structured so that it can be changed in stages.

Embodiment and operation Hereinafter, an embodiment of the present invention will be described based on FIG. 3. 11 is a punch fixedly held on a bolster 13 via a punch holder 12, and 14 is a die fixedly held on a slide 15. Reference numeral 16 denotes a pressure pad which is disposed in a recess 17a formed in the press head 17 at a position below the bolster 13 so as to be able to rise and fall freely, and a plurality of pressure pins 18 are inserted into the bolster 13 and the punch holder 12 and are erected on the upper surface thereof. At the same time, a pressure ring 20 is provided at the upper end of the pressure pins 18, which is located around the punch 11 and presses and holds the peripheral edge of the blank 19 in cooperation with the die 14. Reference numeral 21 denotes a pneumatic cylinder disposed at the center of the recess 17a for urging the peripheral edge of the blank 19 toward the die 14 with a predetermined pressure via the pressure pad 16, that is, the pressure ring 20. 22 is a pneumatic circuit for the pneumatic cylinder 21, and a pressure reducing valve 24 and an air tank 25 for absorbing shock are interposed in the middle of an air pipe 23 that supplies air pressure from an air source to the pneumatic cylinder 21 in order from the upstream side. . Reference numeral 26 denotes a hydraulic cylinder for urging the pressure pad 16 in a direction (downward) that reduces the urging force of the pneumatic cylinder 21. A plurality of hydraulic cylinders 26 are fixedly arranged on the lower surface of the press bed 17 at positions around the pneumatic cylinder 21, and the piston rod 26a thereof is pressure pad 16
It is connected to the lower edge of the rim. Then, the downward pressing force (pull-down force) of the hydraulic cylinder 26
can be changed during the drawing process.
That is, the hydraulic pressure supplied to the hydraulic cylinder 26 can be adjusted in a plurality of stages, for example, in three stages. Here, to explain the hydraulic circuit 27 of the hydraulic cylinder 26, the first to fourth return pipes 31 extend from the middle of the hydraulic pipe 30 that supplies hydraulic pressure from the oil tank 28 to each hydraulic cylinder 26 via the hydraulic pump 29.
- 34 are branched, and further, first to fourth relief valves 35 to 38 are interposed in the middle of the first to fourth return pipes 31 to 34, and first to third return pipes 31 to 33 are interposed in the middle. - First to third electromagnetic switching valves 39 to 41 are interposed so that the third relief valves 35 to 37 can be selectively used. If the set pressures P ₁ , P ₂ , and P ₃ of the first to third relief valves 35 to 37 are set to increase in sequence, the hydraulic pressure supplied to the hydraulic cylinder 26 can be adjusted in three stages. can do. In addition, the set pressure of the fourth relief valve 38
P ₄ is for emergency use, and the first to third relief valves 3
It is higher than that of 5-37. 42 is a main electromagnetic switching valve for opening/closing the circuit provided in the middle of the hydraulic piping 30, and 43 is an accumulator for absorbing shock.

Next, the effect will be explained.

First, air is supplied to the pneumatic cylinder 21 at a predetermined pneumatic pressure, and the main electromagnetic switching valve 4 is supplied to the hydraulic cylinder 26 as shown in FIG.
2 and the first electromagnetic switching valve 39 are operated and oil is being supplied at a pressure of _P1 or less, the slide 15 descends to hold the peripheral edge of the blank 19, and the die 14 starts drawing. be done. As the drawing process progresses, the first
If the relief pressure is changed stepwise from P ₁ to P ₂ and from P ₂ to P ₃ by sequentially switching from Since the force holding the peripheral edge of the blank 19 is gradually weakened, a good product can be obtained.

Effects of the Invention According to the above-mentioned die cutting device of the present invention, a hydraulic cylinder 2 is provided to reduce the pressing force of the pressure ring that presses and holds the peripheral edge of the blank between the die and the hydraulic cylinder 2, and the hydraulic pressure supplied to the hydraulic cylinder is provided. Since a switching valve and a relief valve are provided to change the pressure, the holding force of the peripheral edge of the blank, that is, the pressure of the dictation, can be changed in stages during the drawing process, making it possible to obtain a good product.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a conventional example, and FIG. 3 is a cross-sectional view of an embodiment of the present invention and its circuit. 11... Punch, 14... Die, 15... Slide, 16... Pressure pad, 19... Blank, 20... Pressure ring, 21... Pneumatic cylinder, 26... Hydraulic cylinder, 27...
... Hydraulic circuit, 28 ... Oil tank, 29 ... Hydraulic pump, 30 ... Hydraulic piping, 31 to 34 ... Return pipe,
35-38...Relief valve, 39-41...Solenoid switching valve.

Claims (1)

[Scope of utility model registration request] In a die cutting device, the pressure pad is provided with a pressure ring on its upper surface that holds the peripheral edge of the blank between the die and a pneumatic cylinder that urges the pressure pad upward, and the pressure pad is moved in a direction that reduces the urging force of the pneumatic cylinder. A hydraulic cylinder is provided, and a plurality of switching valves and a plurality of relief valves are provided in the hydraulic circuit of the hydraulic cylinder so that the hydraulic pressure can be changed in stages. Device.