US2443336A

US2443336A - Electric hot forming apparatus

Info

Publication number: US2443336A
Application number: US564649A
Authority: US
Inventors: George A Waldie
Original assignee: HPM Development Corp
Current assignee: HPM Development Corp
Priority date: 1944-11-22
Filing date: 1944-11-22
Publication date: 1948-06-15
Anticipated expiration: 1965-06-15

Description

G. A. WALDlE 4 2,443,336

ELECTRIC HOT FORMING APPARATUS June '15, 1948.

Filed Nov. 22, 1944 2 Sheets-Sheer, 1

,/ Ld "50 INVENTOR GEORGE A. VA LDIE ATTORNEYS June 15, ,1948. w D E 2,443,336

ELECTRIC HOT FORMING APPARATUS Filed Nov. 22, 1944 2 Sheets-Sheet 2 I 76 JTE L yfl Ll/ //[/l ma ENTO 650 A. WA E J-.A...;. 127ml...

Patented June 15, 1948 UNITED PATENT OFFICE 2,443,336 ELECTRIC n01 FORMING- APPARATUS George A. Waldie, Mount Gilead,- ()lno assi gnor to H=P-'M Development Corporation; Wilmington, Del.,- a corporation of Delaware Application November 22, 1944,- Sei-ia Ne. 564,649

Claims.

This invention relates to a method and apparams for treating metals. Particularly, this invention relates to a method and apparatus for hot press working of metals into workpieces 5y either formin drawing or forging.

In the forming of workpieces from heavy plates or bars of metal, or where the now of the metal into the finished workpiece is considelalil t is of advantage to work the said metal while it is hot. By having the metal hot; deeper draws can be made, superior forgings are produced and heavy sections may be formed which would require several pressing operations and possibly annealing operations if the metal were worked cold.

Usual y, the metal is preheated in'a furnace and carried to the press where it is subsequently worked in a suitable die or dies between press platens. This involves" the maintenance of a sizeable furnace and an inefiicient cycle inasmuch as considerable heat may be dissipated hi the transporting of the workpiece to the press.

Accordingly, it is a primary object or this invention to provide an improved method and so paratus for hot workingmetals.

It is another object to provide an apparatus for heating the metal in the press in which it is to be worked.

It is another object to provide eiectrical means for accomplishingthe forging objects.

It is another object to provide an apparatus for heating a blank in' apress and for thereafter shearing out and forming the center'and uni forin'ly heated portion of the said blank.

It is another object to provide a press having a, blankholder adapted to' work met-e1 according to the foregoing objects. v

These and other objects and advantages will become more apparent upon reference to the accompanying drawings, in which:

Figures 1', 2 and 3 are all diagrammatidviews of a press adapted to work metal according to this invention; I

Figure 4 is a diagrammatic view of a press naving a. blankholder the press being adapted to work metal according to this invention;

Figure 5 is a View similar to Figure 4 but shows a modified heating arrangement for the metal to be worked; Y 7

Figures 6 and '7 Show, diagrammatical hav'y' forming or forging operation performed according to this invention.

General arrangement According to this invention, a press mung 2 cooperating dies adapted to form a workpiece is equipped with electrode units adapted to clamp a; blank along the periphery thereof. Electricity is'theii passed through the electrodes and blank so that the latter becomes heated to the proper working temperature.-

When the blank has reached the proper tem'= perature, it is sheared as between the electrodes 50 that the heated center portion lays over one of the die member's. The working operation is then performed. 7

According to one modification, the shearing means may comprise a blankholder which, subsequent to the shearing operation, irons out the edges of the blank during the drawing operation in a manner well known in the blankholder art.

According to another modification, the heating electrodes merely abut the edges of a workpiece and, when the latter is heated. retract so as to drop it into a die cavity where it may be worked by a second die member.

Structural arrangement Ref rrin to Figures" 1. 2 sea 3 there is sho n aporuqn of a press structure comprising a die [0 which has a cavity l2 therein. The edge of the die lfl comprises upstanding portions l4 whch serve to" define edges for the shearing off of the blank I 6. v

Roiprocably mounted above the' die i6 is a die" or punch I'ne'r'r'ib'ei 18 adapted to be moved into the cavity I2 for forming the blank therein.

, Also rciprocable toward the die lfi is a shear 20 which comprises the edge portions 22 adapted, in cooperation with the edges M, to shear off thebnnk' I6.

On either side of the die I!) are shown the clamps 24 which comprise a lower arm 26 and an upper arm 28 pivoted together at 30 and adapted at their outer ends to engage the edge of the blank l6.

Pinned to the arm 25 isa rod which passes through the upper arm. 28 and has pivo'tally secured thereto the cam 34. 13y rotation or the dam the arms 26 and 22' may be moved relatively so as to clamp or unclain'p the blank l6. A sprin 36 assists in the opening of the arms 26 and '28 to release the said blank while a spring 3!? serves to urge the complete electrode unit 24 about-its pivot 30 so that the blank I6 issuppdrtd above the upper surface of the die Ill.

Connected with the electrodes are the wires 410 and 4.2, the latter of whic'h comprises a switch 44, The wires '40 and 42 lead to any suite-file source of electrical energy which may be direct current or alternating current as desired.

The electrodes 24 are preferably insulated from their supports by the insulating pads 45 and 48.

Operation The apparatus is shown in Figure 1 withthe blank I5 clamped between the electrodes and the switch 44 closed so that electric current is. passing through the said blank.

After the blank has been sufiiciently heated, the switch 44 is opened and the shear 201s. advanced to its Figure 2 position. The advancing of the shear 20 presses the blank I6 against the edges I4 so that the edges 22 of the shear 20 will shear off the central portion of the blank. At

this time the springs 38 yield to permit the blankmay be moved upwardly to eject the workpiece from the cavity I2.

The cam 34 is then rotated to permit the

arms

26 and 28 of the electrodes 24 to open so that a new blank may be inserted and operated.

Modification of Figure 4 In Figure 4 there is illustrated a press having a die member 52 which comprisesthe shearing edges 54. A pair of clamps 56 support a blank above the edges 54 and also conduct current throughthe said blank for heating it to the proper working temperature.

A platen 58 is reciprocable toward andaway from the die 52 by means of a ram 50. The platen 58 carries a second die member or punch 62 which is adapted to cooperate with the cavity 64 in the die 52 in order to form a workpiece.

Also carried by the platen 58 is the blankholder-shear 66 which has attached thereto the plungers 68 extending into the cylinders I of the platen 5B, The rods 12 serve to support the is blankholder E5 on the platen 58 when the latter is retracted.

A conduit means I4 connects the cylinder with an inwardly opening check valve I6 and on the platen 58, actuates the solenoid 86 of the,

valve I8 to close the latter. 7 Operation of the modification of Figure 4 In operation the device of Figure. 4 operates substantially as the device shown in Figures 1 to 3, inclusive, except for the blankholdingaction of the member 66. The main platen '58 moves downwardly toward the heated workpiece until contact of the member 66 with the said workpiece is imminent. At this time the switch 82 is actu-v ated to close the valve I8, thus entrapping fluid in the cylinders I0. With the fluid trapped in the cylinders 'IIlfurther movement downward of the platen 58 drives the member 56 against the blankv 88 and shears ofi the central portion thereof. As.

soon as the shearing operation is completed, the switch 82 opens and permits the valve 78 to-open.

Further movement downward of the platen 58 then brings the member 66 into blankholding re- 4 lationship with the sheared off blank while the punch 62 advances into the cavity 64.

During the advance of the plunger 62 into the cavity 64 the blankholder plungers 58 advance into the cylinders I0 and expel fluid therefrom through the relief valve 80, the valve 80 being adjusted to provide suitable pressure in the cylinders I0. i

Following the forming operation, the main platen is retracted, the workpiece is removed and a new blank is inserted between the electrode clamps 56.

Modification of Figure 5 The modification shown in Figure 5 is substantially identical with the form shown in Figure 4. except that the blank is gripped between the electrodes and 92, the latter of which is reciprocated by the fluid motor 94, In operation, the fluid motor 94 is actuated to move the electrode 92 upwardly against the electrode 90 and, when the workpiece is heated to the proper temperature, the motor 94 is actuated so as to drop the blank upon the upper surface of the die member. Thus, it is not necessary to provide yielding means in association with the electrode clamps in order to provide for the proper shearing action of the shear. In this view the parts similar to those in Figure 4 bear similar numbers.

Modification of'Figures 6 and 7 In Figures 6 and '7 is shown an apparatus comprising a stationary die I00 and a movable die or punch. A pair of electrodes I04 are adapted to be reciprocated laterally so as to engage the edge of a workpiece I06.

After the electrodes are engaged with the workpiece, electric current is passed therethrough until the workpiece has attained the proper temperature. Thereafter the electrodes are retract-- ed to their Figure 7 position so that the heated workpiece falls into the cavity of the die I00. The punch I02 is then moved into pressing relationship with the die I00 and the workpiece I06 is thereby formed to the proper shape. 7

It will be apparent that this invention provides a means for rapidly and efficiently heating a blank to proper working temperature. This invention also provides means for trimming off the portion of the blank which is chilled by contact with the electrodes so that the entire piece being worked is at the necessary temperature.

, It will be apparent that the apparatus shown is subject to many modifications without departs ing from the spirit of this invention. For example, the workpieces shown in the drawings might either be substantially rectangular blanks or circular as desired, the heating in either case being accomplished by properly positioning the electrodes around the periphery of the said blank.

Accordingly, it will beunderstood that I desire tocomprehend such modifications and. substitution of equivalents as may be considered'to come within the scope of the appended claims.

I claim:

1. An apparatus for shaping metal sheets comprising a die having cavity, a reciprocable punch adapted to cooperat with said cavity for form-.

ing said sheet, electrically conductive clamp.

means adapted to clamp the marginal portion of said sheet and to support the same between said punch and die, means selectively operable for energizing said clamp means, and means separate from said punch and die for shearing off the marginal portions of said sheet prior to the shaping of the same by said punch and die.

2. An apparatus for shaping metal sheets comprising a die having a cavity and a shearing edge, a shaping member adapted to cooperate with said cavity for forming said sheet, a shearing member adapted to cooperate with said shearing edge in order to blank out said sheet, electrode means adapted to engage the marginal portion of said sheet and to conduct electric current through said sheet for heating the same, means for actuating said shearing member, and means for actuating said shaping member.

3. A press for shaping metal sheets comprising a die having a cavity, a shaping member adapted to cooperate with said cavity, first and second shearing members and a blank holder member, means for supporting said sheet between said die and said shaping member, means for passing electric current through said sheet so as to heat the same, means for actuating said shearing members for shearing ofi the edge of said sheet, means for advancing said blank holder to engage said sheet, and means for advancing said shaping member for forming said sheet.

4. A press for hot forming metal sheets comprising a first shaping member having a shearing edge, a second shaping member adapted to cooperate with said first shaping member, a blank holder having a shearing edge adapted to cooperate with the shearing edge of said first shaping member, means for supporting a metal sheet transversely between said shearin edges, means for passing electric current through said sheet for heating the same, means for advancing said blank holder so that said sheet is sheared off by said shearing edges, and means for simultaneously urging said blank holder against said sheared off blank and for advancing said second forming member into said blank.

5. A press comprising a stationary die member, a stationary shearing edge, a movable die member, a movable blank holder having a shearing edge adapted to cooperate with said first shearing edge, a platen mounting said movable die member, piston-cylinder means in said platen adapted to advance said blank holder-shear, electrically conductive clamps adapted to support a metal sheet between said die members, means for energizing said clamps for electrically heating said sheet, and means operable first to advance said blank holder-shear to blank out said sheet and thereafter to advance said second die member to form said sheet.

6. The combination in a press having a blankholder, 2. platen supporting said blankholder, a first shearing edge on said blankholder and a second shearing edge which is stationary, of means supporting a sheet of metal between said shearing edges, means for connecting said supporting means to a source of electrical energy for heating said sheet, means for advancing said platen to bring said shearing edges into cooperative relationship, means for preventing relative movement between said platen and said blankholder during the shearing action of said shearing edges, and means for thereafter permitting relative movement between said blankholder and said platen.

7. In a press for hot forming workpieces, spaced forming members and spaced shearing members, means for supporting a workpiece in the space between said members, electrical means for heating said workpiece to working temperature while it is so supported, and motor means for moving said shearing members relatively toward each other for shearing oil? a portion of said workpiece and also for moving said forming members relatively toward each other for forming the sheared ofi portion.

8. In a press for hot forming workpieces, a first forming member and a first shearing member, a second forming member and a second shearing member spaced from said first members and defining a workpiece receiving space, means for supporting a workpiece in said space, electrical means for heating said workpiece to working temperature while it is so supported, and motor means selectively operable for moving said first and second members relatively toward each other for first shearing out a blank from said workpiece and for thereafter shaping it.

9. In a press for hot forming workpieces, first and second forming members, first and second shearing edges carried by said forming members and one bein movable relative to its supporting member, means for electric-ally heating a workpiece supported between said members, means for moving said members relatively to bring said shearing edges into operative engagement, means for making said one edge rigid relative to its supporting forming member during the shearing operation, and means for thereafter making said last mentioned means inoperative to permit said one edge to move relative to its supporting forming member during the forming operation.

10. A press having a stationary die member, a stationary shearing edge, a movable die member, a movable blankholder having a shearing edge adapted to cooperate with said stationary shearing edge, a platen mounting said movable die member, piston-cylinder means associated with said blankholder and said platen reponsive to relative movement therebetween to generate blankholding pressure on the former, means for supporting a workpiece between the dies and means for electrically heating a workpiece so supported. means for advancing said platen to bring said shearing edges into cooperative engagement, means for entrapping fluid in said piston-cylinder means during the shearing operation to prevent relative movement of said platen and blankholder, and means operable thereafter for making said entrapping means ineffective to permit relative movement between said platen and blankholder during the forming operation.

GEORGE A. WALDIE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 486,627 Burton et al. Nov. 22, 1892 1,112,779 Forsyth Oct. 6, 1914 1,242,580 Murray (1) Oct. 9, 1917 1,252,289 Murray (2) Jan. 1, 1918 1,333,036 Robertson et a1. Mar. 9, 1920. 1,658,056 Phelps et a1. Feb. 7, 1928 2,089,030 Kratky Aug. 3, 1937