JPH0225536Y2 - - 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 pusher ring 5 is supported by a pusher 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 amount of squeezing, wrinkles may not be suppressed well, which may have a negative 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 dicing 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 die cutting device, the pressure pad is provided with a cushion pin that can come into contact with the die fixed to the slide, and the cushion pin is urged upward to apply a downward pressing force of the die to the pressure ring through the cushion pin. A hydraulic cylinder is provided, and a plurality of switching valves and relief valves for changing the pressure are provided in the hydraulic circuit of the hydraulic cylinder, so that the downward pressing force can be reduced 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 these 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, which urges 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. Reference numeral 22 denotes a pneumatic circuit for the pneumatic cylinder 21, in which a pressure reducing valve 24 and a shock absorbing air tank 2 are installed in the middle of the pneumatic pipe 23 that supplies pneumatic pressure from the air source to the pneumatic cylinder 21 in order from the upstream side.
5 is interposed. Reference numeral 26 designates a plurality of cushion pins for the die 14 arranged on the outer periphery of the pressure ring 20, each of which has a lower end connected to a piston rod 27a of a plurality of hydraulic cylinders 27 provided inside the pressure pad 16, and an upper end. The slide 15 extends to the same position as the upper surface of the punch 11 so that it can come into contact with the die 14 when the slide 15 is lowered. The pressing force for compressing the die 14 can be changed during the drawing process. That is, the hydraulic pressure supplied to the hydraulic cylinder 27 can be adjusted in a plurality of stages, for example, in three stages. Here, to explain the hydraulic circuit 28 of the hydraulic cylinder 27, the oil tank 29
A branch pipe 33 with an accumulator 32 for shock absorption connected to the tip is provided in the middle of a hydraulic pipe 31 that supplies hydraulic pressure to each hydraulic cylinder 27 via a hydraulic pump 30.
The first to fourth return pipes 34 to 37 are branched from the middle of 3, and first to fourth relief valves 38 to 41 are interposed in the middle of the first to fourth return pipes 34 to 37, and In the middle of the third return pipes 34 to 36, the first
- First to third electromagnetic switching valves 42 to 44 are interposed so that the third relief valves 38 to 40 can be selectively used. And the first to third relief valves 38
For example, if the set pressures P ₁ , P ₂ , P ₃ of 40 are set to increase in order, the hydraulic cylinder 27
The hydraulic pressure supplied to the can be adjusted in three stages. In addition, the set pressure P ₄ of the fourth relief valve 41
are for emergency use, and the first to third relief valves 38 to
It is higher than that of 40.

Next, the effect will be explained.

First, air is supplied to the pneumatic cylinder 21 at a predetermined air pressure, and the first electromagnetic switching valve 42 is operated to supply oil to the hydraulic cylinder 27 even at a pressure of P ₁ or less, as shown in FIG. While the blank 19 is being supplied, the slide 15 descends to hold the peripheral edge of the blank 19, and the die 14 starts drawing. As the drawing progresses, the first to third electromagnetic switching valves 42
~44 in sequence to increase the relief pressure from P ₁ to P ₂
If you change it step by step, pressure ring 20
Since the pressing force of the die 14 against the blank 14 is reduced and 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 is provided which reduces the downward pressing force of the die via a cushion pin, separately from the pressure ring which presses and holds the peripheral edge of the blank between the die and the die. Since a switching valve and a relief valve are provided to change the hydraulic pressure supplied to this hydraulic cylinder, 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. Obtainable.

[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... Cushion pin, 27...
Hydraulic cylinder, 28... Hydraulic circuit, 29... Oil tank, 30... Hydraulic pump, 31... Hydraulic piping, 32... Accumulator, 33... Branch pipe, 34-37... Return pipe, 38- 41... Relief valve, 42-44... Solenoid switching valve.

Claims (1)

[Scope of utility model registration request] In a die cutting device having a pressure ring provided on the upper surface with a pressure ring for holding the peripheral edge of the blank between the pressure pad and the die, and a pneumatic cylinder that urges the pressure pad upward, the pressure pad is placed in contact with the die fixed to the slide. A hydraulic cylinder is provided which urges the cushion pin upward to reduce the downward pressing force of the die against the pressure ring via the cushion pin, and a hydraulic cylinder is provided in which pressure is applied in the hydraulic circuit of the hydraulic cylinder. A dictation device characterized in that a plurality of changeover valves and a plurality of relief valves are provided so that the downward pressing force can be reduced in stages.