US3518860A - Set-up for explosive forming - Google Patents

Description

y 7, 1970 R. v. PIKHTOVNIKOV ET AL SET-UP FOR EXPLOSIVE FORMING Filed April 4 1968 OODOOGOOOOOOODOOO Unlted States Patent 01 3,518,860 SET-UP FOR EXPLOSIVE FORMING Rostislav Vyacheslavovich Pikhtovnikov, Prospekt Lenina 3, kv. 227; Alexei Alexeevich Gubsky, Ulitsa Ekonomicheskaya 7, kv. 19; Vladimir Karpovich Borisevich, Zhildon Khai 1, kv. 17; Lidia Rostislavovna Kiriclienko, Prospekt Pravdy 7, kv. 227; Albert Petrovich Barsukov, DMS, kv. 4; Arkady Fedorovich Plisko- Vinogradsky, Ulitsa Frunze 15, kv. 9; Vladimir Ivanovich Shalygin, Zhildon Khai 1, kv. 31; and Georgy Arkadievich Repin, Ulitsa Summskaya 45, kv. 11, all of Kharkov, U.S.S.R.; Anatoly Anatolievich Buzukov, Morskoi prospekt 36, kv. 28, Novosibirsk, U.S.S.R.; and Leonid Vsevolodovich Litovsky, U]. 23 Avgusta 33, kv. 66; and Valery lvanovich Eliseev, DMS, kv. 53, both of Kharkov, U.S.S.R.

Filed Apr. 4, 1968, Ser. No. 718,700 Int. Cl. B21d 26/08 US. CI. 72-56 2 Claims ABSTRACT OF THE DISCLOSURE An apparatus for the explosive forming of sheet material. The sheet material is placed on a die within a chamber provided with a header surrounding the die. Fluid is sprayed out of the header to form a domed curtain over the die and workpiece. The spray constitutes the medium that transmits the explosive energy to the blank.

This invention relates to forming equipment wherein no presses are used, namely to explosive forming equipment.

Most successful and effective use of the invention can be expected in the production of large-size articles (for example, articles with cross sections of over 2 m.).

Explosive forming set-ups are well known. In these setups fluid medium which fills a vessel, transfers to the blank fixed in a die the explosion energy of a charge fixed in the vessel by some arrangement. The vessel can be of two types: stationary or single-use type.

The stationary vessel is a reinforced concrete basin with a metal lining. The die with the blank and the arrangement to fix the charge are located within the basin filled with fluid medium.

A disadvantage of stationary basins lies in a great labour consumption and cost to build the basin itself. In the process of operation the basin walls are eventually destroyed by shock Waves in the fluid medium resulting from the charge explosion.

Single-use vessels are made of cheap materials (say, cardboard, veneer). These vessels are placed on the die with the fixed blank, prior to the explosion. The charge fixture is mounted inside the single-use vessel.

Employment of single-use vessels is limited by the article overall dimensions (to be not more than 2 111.). Charge explosion in a single-use vessel causes a strong air blast wave and fluid medium splashing. Auxiliary time to mount the single-use vessel increases the forming cycle time.

The object of the present invention is to provide an explosive forming set-up that would be of simpler design as compared to the prior-art installations of this type and would have greater production potentialities.

Another object of the present invention is to design an explosive forming set-up that would be reliable in operation and convenient in service.

And still another important object of this invention is to design a set-up that would be cheap to make.

In compliance with the afore-mentioned and other objects of the invention the device for fluid medium in ice the proposed set-up constitutes, according to the invention, at least one header surrounding the die and having jets to spray the fluid medium so as to create over the die and the charge fixture a domed curtain whose dropping streams form the medium that transmits explosion energy to the blank.

In case the proposed set up is employed inside a closed building, it is advisable to locate the charge fixture and the die with the 'header in a buried armoured vessel. The best solution will in this case 'be accomplished by employing, in the top part of said vessel, an additional header with jets spraying fluid medium in order to form a curtain preventing fountains of fluid medium to be thrown out of the vessel at the moment of explosion.

Such a design of the suggested explosive forming setup makes it cheap to construct, reliable in operation, convenient in service and promising great production potentialities.

Besides, the production cycle time is sharply cut down due to decreased auxiliary time.

The invention is further explained by a detailed description of a preferred exemplary embodiment thereof with reference to an appended drawing, wherein:

FIG. 1 is a longitudinal section of the set-up of the invention.

The explosive forming set-up has a buried armoured vessel-pit 1, wherein anvil 2 mounts die 3 to locate and fix blank 4. In the set-up there are provided arrangement 5 to fix charge 6 and a device for fluid medium transmitting explosion energy to blank 4. According to the invention this device comprises header 7 surrounding die 3 and having jets 8 to spray fluid mediumwater, which forms a domed curtain 9 over die 3 and arrangement 5 that fixes charge 6. The dropping water streams 10 of curtain 9 are the medium that transfers explosion energy to blank 4.

When the explosive forming set-up is located inside a closed building, it is advisable to mount, in the pit top part, at least one additional header 11 for fluid medium, with jets 8 to form curtain 12 in order to prevent fountains of fluid medium to spring up from pit 1 at the moment of explosion.

The number of headers 7 and 11 is chosen according to the value of charge 6. The greater the charge value the more the amount of fluid medium (water) to be atomized in the curtains.

The proposed set-up carries out explosive forming in the following way.

Blank 4 is placed on die 3 and fixed by hold-down ring 13. Charge 6 is fixed by means of arrangement 5 at a calculated distance from blank 4. Then water (fluid medium) is pressurized by a pump (not shown in FIG. 1) into header 7 and sprayed through pulverizers 8. In a period of '34 seconds after the pump has been started, a stable domed curtain 9 is formed over die 3 and the charge fixing arrangement 5, the dropping streams 10 of said curtain being directed at the blank center.

At that moment charge 6 is remotely initiated.

Simultaneously with header 7 water is fed to header 11 whose jets spray water forming curtain 12 which prevents water fountains to spring up from pit 1 at the moment of blast.

Explosion energy of charge 6 is transmitted by the dropping water streams 10 to blank 4 thus deforming it.

In a period of 23 seconds after the blast, water feed to headers 7 and 11 is stopped whereupon the finished product is removed from the die.

Employment of the device for fluid medium in explosive forming plants, said device comprising at least one header 7 surrounding die 3 and having jets 8 which spray fluid medium to form a domed curtain 9 over die 3 and 3 arrangement 5 thatfixes charge 6, permits also to obtain a high useful efficiency of explosion energy for blank deformation, as well as to reduce the unfavourable effects of explosions on the personnel and surrounding structures.

The domed curtain 9 of atomized fiuid medium to a considerable extent (up to 90%) absorbs the energy of the shock wave produced by the explosion of charge 6.

Fluid medium is fed through header 7 and jets 8 within a short period of time, which sharply increases labour efficiency due to a decreased duration of auxiliary operations. Besides, fluid medium consumption rate drops substantially.

The proposed set-up permits a short-time assembly, using standard units, of a header of required size according to the overall dimensions of the article.

What we claim is:

1. A set-up for explosive forming comprising: a die to locate and fix the blank; an arrangement to fix the charge; a device for fluid medium transmitting explosive energy to the blank, said device including at least one header surrounding said die and having jets to spray fluid medium which forms a domed curtain over said die with the blank and said charge fixing arrangement, the dropping streams of said curtain constituting the medium that transmits explosion energy to said blank.

2. A set-up as claimed in claim 1, in which said die with a header and a charge fixing arrangement are located within an armoured vessel in Whose top part at least one additional header with jets is mounted to spray fluid medium in order to create a curtain preventing a fountain of fluid medium from being thrown 01f from said vessel at the moment of explosion.

References Cited UNITED STATES PATENTS 3,214,950 11/1965 Nemitz 7256 RICHARD J. HERBST, Primary Examiner

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