US 2947045 A
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211960 w. M. GOLDHAMER 2,947,045 DIE CASTING BAR INJECTION MACHINE Filed Sept. 6, 1957 3 Sheets-Sheet 1 IN VEN TOR. M4 225? M scan/744M 82 1960 w. M. GOLDHAMER 2,947,045
DIE CASTING BAR INJECTION MACHINE IN V EN TOR.
11/44 762 M 6040f/4M6I 1960 w. M. GOLDHAMER- 2,947,045
DIE CASTING BAR INJECTION MACHINE Filed Sept. 6, 1957 3 Sheets-Sheet 5 I N W W' f IN V EN TOR.
Fly! 7 M1725? M solar/4M5? im S a- 68 Patent" 2,947,045 mn CASTING BAR INJECTION MACHINE Walter M. Goldhamer, .2918 Huntington Road,
Shaker Heights, Ohio Filed Sept. 6, 1957, Ser. No. 682,331
Claims. (CI. 22-68) transferring it into a non-immersed piston cylinder assembly for injection into the die.
The former method was used for zinc base alloys and other metals of low melting temperature, while alloys of aluminum and others of higher meltingtemperature were die cast by the latter method.
Both of these methods were unsatisfactory. The exposed surface of the metal bath oxidized in the air and drosses formed, and these oxides and drosses were often carried into the injection system and incorporated into the castings deleteriously affecting their quality. Also, proper compression fit of thepiston and cylinder were difficult to maintain. The immersed injection assembly system was faster, but could not be used for aluminum alloys because absorption of iron from the piston cylinder assembly contaminated the aluminum and destroyed the piston to cylinder compression fit, nor for magnesium alloys'which could not be melted without shielding the surface of the molten metal from air to preventdangerous rapid oxidation, nor for copper base alloys which melted at a temperature so high as to destroy the strength of the piston cylinder assembly if immersed continuously in the molten metal. This has necessitated use of different machines for different casting metals. Where the nonimmersed injection assembly was used, air entrapped in the compression cylinder resulted in oxidation and segregated chilling of the metal, thus causing porosity, contamination and other defects in the casting. To increase the castability of the chilled metal and tofinely divide the entrapped air and gases, excessively high injection pressures were used, increasing the cost of the equipment and the product.
In the present invention, hereinafter called the bar injection method, the desired casting metal and/or alloy, in the form of rods or bars of given cross section and length, are successively fed into a heating chamber of the same inside cross section as the rod or bar, where the inner end thereof is melted and directly injected into the die, by the forced advance of the still solidified outer portion of the rod or bar itself. The outer end of the meltingchamber is provided with a heat exchanger-or chill of the same hollow interior cross section as the bar or rod itself to preserve the shape, form and rigidity of the rod and accommodate the use thereof as a piston for successive injection operations.
It will berecognized that the difl'lculties, enumerated above will be eliminated with this improvedmethod and apparatus since, V
(1) The piston is itself formed of the desired alloy and 2 is continuously providing an air and gas free supply of molten metal.
(2) Melting is carried on immediately prior to injection and free from exposure to ambient air, eliminating oxidation and dross contamination.
(3) Compression fit necessary for pressured injection is automatically and continuously provided outside the zone of contact with the molten metal so that all casting metals or alloys may be handled with the same injection system.
In addition to the foregoing, a further object of the invention is to. provide a bar injection mechanism which may be readily adjusted to effect sufiicient translation of the bar to produce a requisite volume of molten metal for the die cavity. V
A further object of the invention resides in the provision of a bar injection mechanism which is designed for sequential operation with the die closing device.
Another object of the invention is to provide a melting chamber for the end of a bar which is constructed to preclude the admission of air therein. Another object of the invention is to provide a system of metal injection which will permit evacuation of air from the die'cavity without'separately blocking off in-' coming metal flow prior toinjection.
Further objects of the invention reside in a structure" which is economic of manufacture, efficient of operation and adapted for use in die casting machines of various .types and metals or alloys of various chemical characteristics and properties.
Other objects and advantages more or less ancillary to the foregoing, and the manner in which all the various objects are realized, will appear in the following description, which considered in connection with the accompanying drawings, sets forth the preferred embodiment of the invention. 7 r
Referring to the drawings:
Fig. l is a plan view of a fragmentary portion of a die casting machine embodying the improved melting chamber, chill and bar injection mechanism;
Fig. 2 is a side elevational view thereof;
Fig. 3 is a ,vertical sectional view of the bar heater,
chill and guideway for the bar, the section being india' indicated by the line 4-4 in Fig. l;
Fig. 5 is a plan ,view of an alternate form of the bar injection mechanism; and
Figs. 6 and 7 are side elevational views of fragmentary portions of the machine shown in Figs. '1 and 2 illustrate ing alternate forms of mounting the heating unit and the associated chill.
Referring first to Figs. 1 and 2, the die casting machine embodies abase 10, a stationary end plate '11 mounted thereon, a die block 12 rigidly secured thereto,, and a second die block 13 mounted for reciprocative movement towards and away from the fixed die 12. The die 13 is slidably supported on, a member 14 of the customary form employed in die casting mechanism. The translation thereof is effected by a piston cylinder assembly 15 ing element20 embedded therein, a circumambient sleeve 21 and a" jacket 22 ofinsulating material surrounding the sleeve 21. Lines 23 and 24, from the helical heating elei ment, are coupled with a source of electric current. It is Patented .Aug. 2, 1960.
to be understood that the term heating element as used herein, includes all forms of electric resistance wire, electric induction elements, infra-red heaters and means for the circulation of high temperature heatexchangeliqnid; around=the core 19. The inside cross section and length of the core 19 may vary conunensprate theQsize; and
volume ofthetcavitiesyce-mc' andthe canals 25 tl1atlead.
The outer end of the core 19; andsleeve 21 .areaflixe to a tubular chill ,ZGiembodyingradiation fins 21 and a;
helicaligroove 28 on the outer portion thereof, a sleeve 22jthereoverand inletandoutlet Conduits Stlandjlcou:
pled with the groove to accommodate the circulation ,of ,a.
coolant therethrough. Thebore inthetuhe zfi-is disposed in coaxial relation .withwthe ,bore. in the ,,core 19,.and thje shapeand cross section ofcachbore isequal. The
dimensions, ,of the heating element 20and' the size .and
the number of 'convolution's of the groove'may -vary to;
meet thevolunietric requirements of thetdie .cavitiesc-w' and the character of the metal being cast.
The die casting metal is in the .form of. arod or, bar,
Bil-which is :cast, drawn, extrudedorotherwise. formed to a size and crosssection. which snugly, though slidably, engages the similarly shapedbore in the. core 19. andtube. 26., The lengthof the casting metahbarsfil mayvary tomeet the available ,spacein the environsofthe machine and the lineallimitation imposed in themanufacture of the bars. The metal, per se, or :alloythereofis controlled I bvthe demands of the, work being die cast,
Eachbar 32v is inserted intothebor-e 26b. of the ,chill 2 6,and isrprogressively advanced therein, by -a feed mesh-- anism,-such-as the clutch and ram device villustrateduin,
Fig. l, the toggle clamp and linkageshown in .Fig, 5, orany ratchet pushers of a .well known form. Asshown in Fig. .1, the end platell of the machine is provided with a pair of parallel columns 33 constituting ways for a slide 34 m ounted thereon. The slide is reciprocatedtowards and away from the plate 11 by hydraulic rams 35 secured to a stanchion 36 mounted on the base of themachine parallel to the plate 11. The slide-is provided with, a pair of opposed .shoes 37 mounted on piston, rods.3 8 in cylinders 39 .carried by-the slide frame.
The circumferential wallof the chill,26-is.rnachined with opposed slots 26a therein for the reception of the shoes37. The shoes engage the bars-asthey arei lccessively fed through the chill, and the slots 26a are ofsufiiicient length to assure stability and-coaxial alignment oftheend of the bar being used with anew ,barinjectedinto the chill. The rearward end, of they chill 25 is hellmouthed to accommodate the ready entry ofthe bars injected therein.
The rams 35, cylinders 39, and cylinder assembly are all connected to a control valve- (not shown) designed to effect the sequential actuation of thepistons, therein.
Thus, after the die block 13 is brought into abutting ,engagement with the die 12, the cylinders 39 will effect-the.
engagement of the shoes with, the bar 32, then the ram pistons 34a will advance the slide 34 inwardly. In. the alternate form of the pusher, illustrated in Fig. 5, the,
mechanism comprises a pairof arms 40 and 41' pivoted intermediate their ends-on a cross head 42. Each arm is. provided at its outer end with opposed shoes 44 mounted? in toggle joints on the arms. The;opposed ends ofthe arms 40 and 41 are machined with arcuate slots-.45there: in, engaged with pintles 46 in a-sliding crossbar43. The cross;bar 43. is advanced forwardly by pistons in-cylinders 48. mounted on the cross head 42,- thereby effectingclamping, engagement. of the shoes 44 with the; bar 32.
Actuation of the pistons in the cylinders-35 willjeffect' they-inner; translation or feeding cycle of the bar ;32.
tended from; the bottom -.of .thestationary; die. 12.1 1 1; the.
bar injection mechanism therefor (not shown) extended therefrom below the machine parallel to the base 10. This arrangement affords the advantage of having the molten metal supply in close proximity to the die cavity, and thus eliminates the possibility of solidification of the molten metal before it reaches the die. In Fig. 7 where the area around the machineiiszlimited, a vertical post 50 y be mou te onthehase p r le .tqi d plate 11, and 'a-heating unitSi of analternate-form andchill may beasecured. to-.the: post sorthe. bar 32 protrudes upwardly. The machinemayybegprovided with a storage rack or hopper and automatic bar loading device therefor to facilitate-continuous operation of the'machine and to shorten the operating time: thereof.: Such device and its appurtenances is contemplated as falling within the scope or the present invention, though not illustrated herein. The invention further comprehends a bar injection mechanism having lirnit switchesthereonfor holdingtheshoes orv jaws -of.the clutch engaged with thebar during all or.
part of the retractive movement of;the slide. The actua-. tion ,or. position of theseswitches maybe made .to accommodateadjustmentsso the molten metal remaining inthepassageway between the die..cavity and the heating unit will be forced, back,by: atmosphericpressure, as thedie halves c, are parted, ,thus preventing dripping of, molten metal .fromthe die end .of the; passageway while the die halves ,are'. apart.
In operation, a bar 32 is inserted, intthe. bore ,ofpthe' chill tube 26 and advanced therethroughinto heating unit 17 where;the endportion thereofismelted by the heating.
danger oftflowrofr molten metal into the die'cavitya and without the necessity; of. mechanically; blocking- ;themetal flow during evacuation; as :in .this systemthe atmosphericpressure-is excluded from contact with the moltenernetah Thetravel of thecasting metalbaris'regulated to displace a sufiicient volumeof-molten metal to completely fill the die cavities- When the-slide reaches itsinnermostposition, the portion of thebar formerly :suppor-ted in'thc chill, is'melted in preparation for the successiveinjection cycle; of the machine. As the'slide is-retracted; the'shoes will slide'over the bar, but uponreversal ofrth'e movement thereof, the shoes: re-engage the-bar and effect the inward translation thereon;
It will be seenfrom the foregoing that themetal within the heatingunit, 17,is never exposedto atmosphere, thus there-isno possibility ofoxidation. The molten metal is injected into'the die cavities immediately after it reaches its molten state and before absorption thereofof iron or other metalsehaving a deleterious effect on the die casting material, and the bar or bars are formed of the metal or alloy that is desired for the casting being made.
The rateof movement of the=slide 34 and the length of thetravel or stroke thereof is regulated-by adjustment of the valves'(not shown) connected to the rams 3S illustrated in Fig. l, thoughother'rnech'anism for the reciprocative movement andspeed of the slide, suchas a cam and rack; pinion or crank, and connecting rodassembly mayibe substituted therefor with equal facility.
Although the foregoingdescription is necessarily of a detailed character, in order that the inventionmay be completely set: forth;-.it is to-be understood that the specific terminology is not intended .tobe restrictive or confining, and that various rearrangements ofeparts and mo difications. joidetaihmaybe resorted .towithout departing from the scope or spirit of the invention as herein claimed.
What is claimed is:
1. In a die casting machine embodying a fixed and a movable die block, each having a die cavity therein, the combination of a heating unit for melting-the end of a bar of die casting metal and a contiguous chill to preserve the solidified form of the bar, said heating unit comprising a core having a bore therein for the support of the bar, a helical electric resistance element circumambient the perimeter thereof to melt the portion of the bar, therein, said chill comprising a tube aflixed to said core in coaxial alignment therewith, said tube having a helical groove in the perimeter thereof, a sleeve circumambient' said groove constituting a waterjacltet to maintain the solidification of the portion of the bar therein, and mechanism rearward and coaxial said chill to progressively feed the bar into said chill and the molten metal in the heating unit into the die cavities.
2. In a die-casting machine embodying a fixed and a movable die block having die cavities therein, the combination of the die casting machine with a heating unit for melting the end of a bar of die casting metal and a contiguous chill to preserve the solidified form of the bar, said heating unit comprising a tubular core for the support of the bar, an electric heating element circumambient the perimeter thereof to melt the portion of the bar therein, said chill comprising a tube aflixed to said tubular core in coaxial alignment therewith, said tube having a helical groove in the perimeter thereof, a sleeve circumambient said groove constituting in combination with the groove a passageway for the circulation of a coolant to solidify the portion of the bar therein, and mechanism rearward and coaxial said chill to progressively advance the bar into the chill and inject the molten metal in the heating unit into the cavities in the die when the die blocks are closed.
3. A die casting machine embodying a fixed and a movable die block, each having die cavities therein, a heating unit for melting the end of a bar of die casting metal and a contiguous chill to preserve the solidified form of the bar, said heating unit comprising a tubular support for the bar, a heating element engaged with the perimeter thereof to melt the portion of the bar therein, said chill comprising a tube affixed to said core in coaxial alignment therewith, said tube having grooves in the perimeter thereof, a sleeve circumambient said grooves defining a coolant passageway to maintain the solidification of the portion of the bar therein, said heating chamber having a discharge opening in the inner end thereof communicating with the die cavities, and a clutch mechanism rearward and coaxial said chill to progressively feed the bar into said chill, the solidified portion of the bar constitutinga pusher to effect injection of the molten metal in the heating unit into the die cavities and to form a metal slug to be melted in the heating chamber for sequential cyclic operation of the machine.
4. A die casting machine embodying a fixed and a movable die block, each having die cavities therein, a heating unit on the fixed die communicating with the die cavity therein for melting the end of a bar of die casting metal, a chill contiguous and coaxially aligned with the heating unit to preserve the solidified form of the bar, said heating unit comprising a core having a melting chamber therein for the end of the bar, an electric heating element surrounding said core to melt theend portion of the bar therein, said chill comprising a tube affixed to said core in coaxial alignment therewith, said tube having a bore therein for sliding engagement With the bar, a helical groove in the perimeter of the tube, a sleeve circumambient said groove constituting in combination with the groove, a coolant passageway to maintain the solidification of the portion of the bar therein, and a clutch mechanism rearward and coaxial said chill to progressively advance the bar into said chill and to progressively inject the molten metal in the heating unit into the die cavities when the die blocks are moved into abutting relation. 7
5. A die casting machine embodying fixed and movable die blocks having die cavities therein, a heating unit on said fixed die block for melting the end of the portion of the bar of die casting metal, a chill contiguous said heating unit to preserve the solidified form of the bar, said heating unit comprising a core having a chamber therein communicating with the die cavities, a heating element contiguous said core to melt the portion of the bar in said chamber, said chill comprising a tube aflixed to said core in coaxial alignment therewith, said tube having a groove in the perimeter thereof and a sleeve circumambient said groove constituting a passageway for circulation of a coolant to maintain the solidified form of the portion of the bar therein, and a unidirectional gripper rearward and coaxial said chill to progressively feed the bar into said chill and to inject molten metal in the heating unit into the die cavities.
References Cited in the file of this patent UNITED STATES PATENTS 1,219,358 Stewart Mar. 13, 1917 2,307,001 Johnson Dec. 29, 1942 2,533,468 Jurgeleit Dec. 12, 1950 2,656,588 Ovshinsky Oct. 27, 1953 2,799,066 Federman July 16, 1957 2,831,214 Eyles et a1 Apr. 22, 1958