US 2935038 A
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May 3, 1960 v. H. CHATTEN APPARATUS FOR METAL FORMING USING EXPLOSIVE PRESSURES Filed Aug. 2e, 1955 H/W/ MZ F12-G. Z.
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APPARATUS FOR METAL FORMING USING EXPLOSIVE PRESSURES This invention relates to an apparatus for forming of metals and alloys by means of pressures developed by explosions.
Stamping, forgingand drawing operations on metal parts ordinarily require two separate dies which are designed for cooperative action. My invention eliminates the requirement for one of the dies and substitutes high pressures of the type obtained by explosions to force a blank into contact with a single die surface. Another feature of the invention is to mount the die member within the explosion chamber so that the pressures are exerted on the die member in every direction, and in this way the die parts are subjected only to compressive forces as a result of the explosion pressures within the-chamber. A particularly advantageous feature of this invention is that it is adapted for hot forming of metals and alloys and without requiring interlitting cooperative die parts.
An object of this invention is to provide a combustion forming apparatus in which a blank to be formed is placed adjacenta die cavity and wherein means are provided for controlling the pressure within the die cavity prior to and during the application of explosive pressures in the chamber. pressure in the die cavity may comprise vacuum forming means to minimize resistance to movement of the blank intothe die cavity or may comprise a vent connecting the die cavity to the explosion chamber or may comprise means for pressurizing the die cavity to reduce the speed of movement of the blank into the die cavity.
IOther and related objects and advantages will appear l hereinafter.
In the drawings:
Figure l shows a preferredembodiment of combustion forming apparatus utilizing this invention.
Figure 2 is a transverse sectional view of a die member and associated parts embodying this invention.
Figure 3 is a sectional elevation showing a modification.
Figure 4 is a sectional elevation showing a further modiication.
Referring to the drawings:
The pressure chamber shown in Figure'l isl defined between the stationary base 11 and the movable shell 12. The shell 12 may be slidably mounted on parallel rods 13 extending through guide bearings 14 and 15. A spring 16 encircling each rod 13 bears against the shell 12 at one end and against a collar 17 at the other. Each collar 17 is adjustably lixed upon its respective rod 13. Each rod 13 may be fixed to a piston 18 mounted in a cylinder 19. A four way valve assembly 20 of conventional design is connected to the cylinders 19 by suitable piping so ythat pressure lluid can be used to extend or retract the rods 13. Y
The joint 21 between the stationary base 11 and the movable shell 12 is designed to be pressure-tight when The means of controlling the closed but to open suddenly to provide a large area vent Y to atmosphere whenever the pressure in the chamber 10 ICC exceeds a predetermined value. Opening of the walls of the joint 21 to form a vent passage occurs when the shell 12 is lifted away from the base 11. The lifting action may come about through the agency of pressure within the chamber 10, or may be accomplished by manipulating the valve 20 to retract the rods 13. In the latter case, the collars 17 engage the shoulders 22 to lift the shell upwardly.
The die member 23 is positioned within the chamber 10 in a manner so that pressure within the chamber is exerted upon all sides thereof. The die member 23 may be formed in one piece, or, if desired, may be provided with segmental inserts 24 having shaped surfaces 25. A metal blank` 26 rests on the surface 27 of the die member and may be clamped in position by any convenient means. Releasable mechanical clamps 28 are shown in Figure 2, while Figure 3 shows electro-magnet clamps 29 and Figure 4 shows pneumatic clamp means including seal rings 30, and vacuum ports 31.
A cover sheet or shield element 32 may be placed over the metal blank 26, if desired, and the shield is held in place by the clamping means. If desired, the shield element 32 may be larger in diameter than the metal blank 36 so that clamping means do not prevent movement of the outer edge of the metal blank 26 and in this way undue stretching of the metal of the blank may be prevented. The suction line 32 is connected through iittings 33 in the terminal block 34 for communication with the restricted passages 35 in the die member 23. Ports 36 connect the passages 35 with the die cavity 37.
Means are provided for heating the die member 23 and as shown in Figure 2 this means includes the electric resistanc'e heaters 38 having plug and socket connections 39 with the terminal block 34. Lead wires 40 supply electricity. The die inserts 24 are heated by conduction.
`In operation, the shell 12 is raised by means of the rods 13 to provide access to the die member 23. A blank 26 is placed in position, together with a shield 32, if desired. The clamping means are actuated to hold the parts 26 and 32 in place. The heaters 38 are energized, and a partial vacuum is produced within the die cavity 37 by means of a vacuum pump (not shown) connected to the Vsuction line`32. The valve 20 is manipulated to lower the shell 12 into sealing contact with the base 11, thereby closing the'joinf 21 and sealing the chamber 10'. An explosion is' then set off in the chamber by means of the device 42. The sudden pressure of high magnitude acts over the surface of the blank 26 and drives the central portion into the cavity 37 into contact with the shaped walls 25. The partial vacuum within the cavity 37 minimizes resistance offered to such movement of the blank 26. The peak pressures within the chamber 10 are relieved as soon as the force of the explosion has carried the shell 12upward against the action of the springs 16, and for a sufficient distance to move the recess 39 away from the lip 40. Gases under pressure then escape along the joint opening 21.
The formed part may be removed from the die member by removing the segmental inserts 24 and then separating them laterally. In some instances it is desirable to pressurize the passages 35 to assist in removing the inserts 24.
It should be noted that the explosive pressures Awithin the chamber 10 act upon all sides of the die member 23, and hence the latter is subjected only to compression forces. Undercuts in the shaped portion of the die are permissible because only one die is involved instead of two. Furthermore, the fact that the die may be heated makes its possible to form such metals as titanium and its 'alloys which must be worked at high temperatures to avoid cracking or fracturing.
The explosions may be generated in any preferred or desirable manner. One method is to ignitconventional explosives within the chamber by conventional means such as electrically operated tiring craps'. Another method is to presvsuieth'e combustion'chalr'n ber and then 'introduce afuel throughanfinjection nozale to effect combustion or comparable tfo` that used in a diesel engine. Where a series of repeated explosions are ref quired, resonant chambers may be employed to prof duce the frequency desired or ya series of explosive. charges may be set oifin a timed sequence." i 'l Y i' Y Having fullyv described my inventiqn, it is to beunderstood that I am not to limitedby the details herein set 'forth but that my invention'vof .the fullY scope of the appended claims, N V I' i y M I claim:V
1. In a combustion-,forming device for shaping a blank into an article, thekcombination comprising a* stationary base, a vertically. movable shellY l choperating.with the base to form a pressurechamber, means forming a presl sure tight seal between thehbase'and shell, lapair of hydraulic cylinder assemblies having parallel piston rods projecting downward therefromfguide means lslidably mounting. the shell on said piston rods, cooperating parts on the piston rod'sand shell` whereby retraction of the piston rods in an' upward direction serves to raise the shell and separate it from the base, means connecting said cylinder assemblies and the stationary base, a die member positioned vyitlklin"t'hefchaibern 'and'rhaving'a cavity shaped in accrdnc'e'vvith `arf-articley to beprnoduced, the die'mmberalso'having'a por ion for'contacting a` blank is position 'aaneen an cavity? inesperadas for 's tid'l denlyiincreasing the pressure vin the chamber .to drive at least a portion of the blank into the cavity to Vbe shaped thereby, the entire surface of said blank,` exposed to the chamber being subjected to the pressure in said chamber, said explosion means acting to lift the shell away from the base and thereby vent the chamber, and means of predetermined resiliency'urging the shell and base into pressure chamber -'forming relation, said resilient means opposing the explosion force to hold the shell and base in pressure chamber forming relation until a pressure is built up suicient to form blank as d esired, the resili ient means then yielding to the. explosiveA force to allowlthe shell and base to movefaparQ-thereby*Venting the chamber. 2. In a combustion-formingdevice for shaping a blank into anY article, the combination comprising astationaify a pressure chamber, means forming a pressure tight seal between the base and shell, a pairof hydraulic cylinder assemblies having parallel piston rods projecting therefrom, guide means slidably mounting the shell on said piston rods, means of predetermined resiliency carried on the piston rods opposing movement of the shell, cooperating parts on the piston rods and shell whereby axial movemerit of the piston rods serves to. move the shell and separate it from the base, means connecting said cylinder 'assemblies 11.1111 the @6151111111 base a die .1111211111111 121251- tioned within the chamber ,a'ndhavingvr a cavity shaped in accordance withman article to be produced, the die member also having a portion for contacting a blank in position adjacent `said cavity, an explosion means for suddenly increasing the prerssdre. in the chamber to drive at least a portion of the blank into the cavity to be shaped thereby, the entire surface of said blank that is exposed to, the Chamber being Subiesfed t9 the Pressure said chamber, said explosion means acting to move the shell away from the base in opposition tothe resilient means and thereby vent the chamber when the pressure in the chamber has been built up suiiicien'tly to form the blank as desired, and means for controlling the pressure within the space between the blank and the die cavity as said blank is shaped.
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