JPH0324261Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field of the Invention) The present invention is a heading machine used for forging bolts, nuts, or other parts from metal materials using punches and dies. This invention relates to a knockout device that serves as a support for the material to be processed and is used to push the material out of the die after forging.

(Description of prior art) In such a former, when the material placed in the die is struck by a punch to form the material, the knockout pin is held in a retracted position during forming and forms the bottom of the die, and then Since the machine is operated to extrude the pressed material from inside the die, it is subjected to powerful punching force tens of thousands of times a day, resulting in severe wear and damage. requires a great deal of effort to perform maintenance, inspection, and replacement work.

Conventionally, as shown in Fig. 5, such a knockout pin was fitted into the hollow part of the mold table from the rear by integrally forming a flange on the rear end of the shaft made of a round bar. If the knockout pin is damaged, not only will it be impossible to remove and replace the knockout pin without removing the die block and disassembling the inside, but it will also tend to expand in diameter due to the strong compressive load acting on the flange. Therefore, it is difficult to set the flange diameter dimension with high accuracy with respect to the hole diameter of the hollow part, so the knockout pin is likely to receive an uneven load.
This may have caused various problems.

For this reason, a device (Japanese Patent Publication No. 53-5983) is generally known that uses a straight round bar-shaped knockout pin to allow the die to be extracted from the front. It has a very complex structure in which a specially processed chuck case, a chuck that expands and contracts due to the wedge action of the ball, a ball cam mechanism, etc. are incorporated to support the knockout pin. Therefore, such a configuration requires a fundamental design change to the structure within the die block, which is disadvantageous in terms of cost and is therefore impractical. In addition, since the knockout pin is subjected to a strong compressive load each time punching is performed, the rear end of the round bar body in particular may become distorted due to the influence of diameter expansion, and the hole diameter of the hollow part may become distorted. It becomes difficult to maintain support dimensions with high accuracy. Therefore, there is a problem in that it becomes susceptible to uneven loads, which causes various problems.

(Purpose of the invention) The present invention addresses these conventional drawbacks, and its first purpose is to remove the knockout pin from the front of the die hole without disassembling the interior in the event that the knockout pin is damaged. The purpose of the present invention is to provide a knockout device for a molding machine that can be easily pulled out and replaced with a new one.The second purpose is to prevent the flange of the knockout pin from receiving compressive loads so that the hollow part of the mold table can be removed. It is an object of the present invention to provide a knockout device for a former that can maintain the outer diameter of a flange portion with high precision with respect to the hole diameter. A third object of the present invention is to provide a knockout device for a homer that has a knockout pin with a simple structure, which facilitates manufacture and assembly, and which is advantageous in terms of cost.

(Structure of the invention) In order to achieve the above object, the knockout device for the homer of the present invention includes a knockout pin made of a round bar inserted into the die and whose rear end is brought into contact with the tip of the extrusion rod main pin. In a knock-out device for a home machine, which is fitted and held in a hollow cylindrical mold base with an open rear end so as to be slidable back and forth, the rear end of the knock-out pin is gripped and held in the hollow part 3a of the mold base. A bushing body that slides back and forth together with the knockout pin, and a spring that is compressed and interposed between the bushing body and the front inner wall of the hollow part of the mold table, the bushing body a flange that slides and guides the bushing body, and a split-cylindrical clamp that elastically grips the rear end of the knockout pin. It is made larger to retain play space.

(Example) A preferred embodiment of the invention is shown below.

Fig. 1 shows a knockout device on the die side, in which a knockout pin 1 is inserted into the die 2 and is fitted and held in a cylindrical mold base 3 with a hollow rear part 3a so as to move back and forth. There is.

The knockout pin 1 is composed of a round bar body 1a made of a straight round bar and a bushing body 1b fitted to the rear end thereof.

The bushing body 1b is fitted into the hollow part 3a of the mold stand 3 with high accuracy according to its hole diameter, and the collar part 4 is slidably guided.
and a split cylinder-shaped clamp part 5 which is integrally formed so as to protrude from the front part thereof. The clamp part 5 is made elastic, and the round rod body 1 is inserted into the center hole 5a.
Insert the rear end of a to push it open and grip it elastically so that it can be attached and detached.

The hole 4a of the flange 4 has a hole diameter larger than the outer diameter of the round rod 1a to maintain a clearance S when the rod is inserted.

The spring 6 is provided in the hollow part 3a of the mold stand 3, and one end is locked to the flange part 4.

A protrusion 7 may be provided at the tip of the knockout pin 1. This protrusion 7 is punched into the material 9 by the punch 8.
This is to improve the protrusion of the meat when it is pressed into the die 2 for heading.However, by providing this protrusion 7, the elasticity of the spring 6 prevents the material from getting stuck to the tip of the punch and becoming difficult to separate. It is possible to forcibly move the knockout pin 1 backward to prevent it from biting. The knock-out pin 1 has a round bar body 1a fitted into the front hole 3b of the mold stand 3 at the front, and a flange 4 fitted into the hollow hole 3a at the rear to be held during forging and knock-out. Prevent pin bending.

In FIG. 1, 11 is a fixed base, 12 is a main pin, 13 is a threaded sleeve, 14 is a push pin, and 15
is the dive block, and 16 is the aircraft.

(Functions and Effects) When the punch 10 moves forward to forge the material loaded into the die 2, the knockout pin 1 is in the retracted position (Fig. 1) so as to form the bottom of the die. Support material 9.

During this forging, the knockout pin 1 is subjected to a strong compressive load, but since the flange 4 is inserted with a play gap S, it does not receive any expansion force, so it maintains high precision with respect to the hole diameter for a long time. can do.

At the time of knockout, the spring 6 is moved forward so as to be compressed. At this time, the tip of the clamp part 5 comes into contact with the hollow front wall 3c of the mold table 3 and the collar part 4 does not come into contact with it, so the spring 6 is compressed without any problem. be able to.

If knockout pin 1 is damaged, the 4th
As shown in the figure, the round bar body 1 is
A is advanced so that it protrudes from the die hole, and is grasped with a tool 17 such as pliers and pulled out. Round rod body 1
The rear part of a is only held elastically by the clamp part 5, so it can easily come off. When replacing the die, push it in from the front of the die and the clamp part can be pushed open again to grip it.

The present invention includes a bushing body 1b that grips the rear end of the knockout pin 1 in the hollow part 3a of the mold table 3 and slides back and forth with the knockout pin, and a bushing body 1b and the hollow part of the mold table 3. A spring 6 is compressed and interposed between the bushing body 1b and the front inner wall 3c of the bushing body 1b. The bushing body has a split cylinder-shaped clamp part 5 which elastically clamps the bushing body, and the hole diameter of the flange part 4 of the bushing body is formed to be larger than the outer diameter of the knockout pin to maintain a play space S. Because of this, it is possible to easily and reliably replace the knockout pin by pulling it out from the front, and it is hollow so that no expansion force is generated in the flange of the bushing body due to the presence of play even under strong compressive loads. Accuracy regarding the hole diameter can be maintained for a long time, and since the existing hollow cylindrical mold stand can be used as is and one bushing body is installed inside the hollow, it is easy to implement, so it is cost-effective. It can be expected to have an excellent practical effect of being advantageous, durable, and highly accurate in that it can be easily obtained at low cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of the device of the present invention, and FIG. 2 is a side view of the bush body, showing the upper half in cross section. FIG. 3 is a front view of the same, FIG. 4 is a sectional view of a main part showing a method for removing the knockout pin, and FIG. 5 is a sectional view of the conventional device. 1... Knockout pin, 2... Dice, 3...
...Hollow mold stand, 4...Flame part, 5...Clamp part,
6...Spring, 1a...Round bar body, 1b...Button body.

Claims (1)

[Scope of utility model registration request] A knockout pin 1, which is a round rod inserted into the die 2 and whose rear end is brought into contact with the tip of the extrusion rod main pin 12, can be slid back and forth on a hollow cylindrical mold base 3 with an open rear end. In the knockout device for a former, the bushing body 1b grips the rear end of the knockout pin 1 in the hollow part 3a of the mold base 3 and slides back and forth together with the knockout pin. A spring 6 is compressed and interposed between the bushing body and the front inner wall 3c of the hollow part of the mold table.
The bushing body 1b includes a flange portion 4 that slides and guides the hollow portion of the mold table, and a split cylinder-shaped clamp portion 5 that elastically grips the rear end portion of the knockout pin. Therefore, the flange 4 of the bush body
A knockout device for a home machine, characterized in that the diameter of the hole is larger than the outer diameter of the knockout pin to maintain a clearance S.