US 3903956 A
Description (OCR text may contain errors)
United States Patent 1191 Pekrol Sept. 9, 1975 1 1 DIE CASTING MACHINE WITH PARTING LINE FEED FOREIGN PATENTS OR APPLICATIONS 536,671 10/1931 Germany 164/120  Inventor: George G. Pekrol, 185 Diamond 399,389 10/1933 United Kingdom Spring Rd., Denville, NJ. 07834 Primary Examiner-J. Howard Flint, Jr.  Flled' Sept. 1973 Assistant Examiner-V. K. Rising  Appl. No.: 394,453 Attorney, Agent, or Firm-Clarence A, OBrien;
Harvey B. Jacobson  US. Cl. 164/316; 164/338; 164/347;
164/348; 164/125; 164/126; 249/67; 249/79 ABSTRACT  Int. (3L2 B22D 17/04 A die casting machine has relatively movable dies lg. 1 1 Field of Search fining therebetween a cavity in which a casting is /3 128, formed and conduit means communicating with the 262, 264, 265, 348, 113, 118, 31 17, cavity and an opening in the outer surface of one of 144 y), the dies whereby molten metal may be injected 314 y), through the opening and the conduit means into the 78, 425/444 cavity. The conduit means consists of a first portion extending from the cavity along the preferably hori-  References Cited zontal parting line surface between the dies and a sec- UNITED STATES PATENTS ond portion, preferably inclined from the horizontal, 1,722,281 7/1929 During 164/112 extending between Opening and the first Portion f 1,927,384 9 1933 Bauer 1 164/318 the conduit. Heating means are Provided adjacent the 2,366,475 1/1945 Bartholomew... 249/68 second Portion of the conduit to maintain the metal 2,438,348 3/1948 Morin 164/113 X therein in a molten state and cooling means are pro- 2.772.454 2/1956 ennan..-- 64/ vided adjacent the first portion of the conduit for 80- 2,773,284 12/1956 Kelly 249/66 C lidif i the molten metal therein 3,233,292 2/1966 Kramer, Jr. et a1 164/251 3,334,378 8/1967 Scherrer-Wirz 6! a]. 425/444 Claims, 4 awing igur s 78 5 56 \\\I\\ i A 70 53V 57 70 54 86 -84 '82 j 74 a9 90 DEE CASTING MAQHKNE WITH PARTING LINE FEED The present invention relates to metal die casting apparatus, and, more particularly, to apparatus characterized by improved means for feeding molten metal to the die cavity.
Conventional metal die casting apparatus, such as commercially available zinc die casting machines, utilize a conventional sprue type molten metal feed whereby the metal is injected into the die in a direction perpendicular to the parting line surface between the dies and the sprue means causes the metal to alter its direction 90 to reach the cavity. According to the present invention, apparatus is provided whereby the molten metal is fed into the die along, i.e., in a direction generally parallel to, the parting line surface. By feeding the metal to the dies in this manner the overall die cost is reduced, the cavity area in the die is increased, less metal is utilized, the dies are able to operate faster and improved quality castings are produced.
Accordingly, it is an object of the present invention to provide injection die casting apparatus which eliminates the need for heretofore conventional sprue Spreaders and sprue bushings and therefore reduces die cost and creates more usable cavity area.
it is another object of this invention to provide an apparatus for injection die casting whereby the heretofore relatively large sprue cone is replaced by a much smaller runner to decrease metal usage, and, by decreasing solidification time in the runner, to allow faster die operation.
it is still another object of this invention to provide an injection die casting apparatus capable of providing improved quality castings.
Other objects and advantages will become apparent from the following description and appended claims taken together with the accompanying drawings.
F 1G. 1 is a front sectional view of the apparatus of the present invention with the dies closed during casting.
FIG. 2 is a front sectional view of the apparatus of FiG. 1 showing the movable die in the open position.
H6. 3 is a front sectional view of the apparatus of H6. 3 showing the casting being ejected from the stationary die.
FIG. 4 is a front sectional view of a conventionaldie casting machine wherein molten metal is injected into the die, via the sprue, in a direction generally perpendicular to the parting line surface between the dies.
Referring first to FIG. 4, there is shown generally at it) the sprue feed type die casting apparatus in common commercial usage. T he apparatus consists generally of horizontally separable dies 12, 14 defining a die cavity 16 therebetween. Generally die 14 is stationary and die 32 is movable relative to die 14 to allow ejection of the cast article. Disposed within and filling the cavity portion of die 12 is contoured impression insert 18a adapted to mate with contoured impression insert 181) carried by die 14 and to define therebetween a mold cavity 29 shaped to conform to the configuration of the article to be cast. An ejector plate assembly includes ejector pins 22 projecting through stationary die 14 and impression insert 18b into mold cavity to eject the cast article from the apparatus when the dies 12, 14 are separated. Movable die 12 has a bore 24 therethrough adjacent the die cavity for receiving a sprue bushing 26. A recess 28 in the surface of die 14 adjacent die 12 in horizontal alignment with bore 24 houses a sprue spreader 30, which spreader has a conical nose portion 31 extending into bushing 26 when the die halves are closed to define sprue cone 32 and thereby to distribute the molten metal into mold cavity 20. The molten metal is provided to the mold cavity via an injection nozzle 34 joined to sprue opening 36 in sprue bushing 26 at one end and operatively associated with a molten metal injection means 38 at the other. For example, the molten metal 40 in melting pot 42 may be injected through sprue 36 by a reciprocating piston 44 drawing metal into nozzle 34 through openings 46 during the piston upstroke and forcing the metal through the nozzle and into the sprue 36 on the piston downstroke.
It will be appreciated that in the conventional sprue feed type die casting apparatus, the molten metal is injected into the die via the sprue in a direction generally perpendicular to the parting line surface between the dies, after which the sprue spreader causes the metal to take a change in direction to reach the mold cavity. In FIG. 4, the parting iine surface, designated by A, is generally vertically oriented.
According to the present invention the sprue means for feeding the molten metal to the die in a direction substantially perpendicular to the parting line surface is eliminated and a small runner which feeds the metal along the parting line surface is substituted. This latter configuration allows the metal to take a more direct, substantially straight-line path from the nozzle to the mold cavity, avoiding the 90 change of direction at the sprue and therefore resulting in less turbulence and more effective hydraulic pressure for filling the cavity. At the same time, eliminating the sprue bushing and sprue spreader reduces equipment costs and contributes to molten metal usage economies.
The die casting apparatus 50 of the present invention is illustrated in FIGS. l-3 to which attention is now directed. Apparatus 50 is similar in many respects to apparatus it) in FIG. 4, differing primarily in the means for feeding molten metal to the cavity. Specifically, apparatus 50 includes a pair of vertically separable dies designated as movable cover die 52 and stationary ejector die 54 defining a die cavity 56 therebetween. A contoured impression insert 58a carried by cover die 52 is adapted to mate with the contoured impression insert 582; carried by ejector die 54. The inserts 58a and 58b are housed respectively within the cavity portions of the cover and ejector dies. When the apparatus is closed, inserts 58a and 58b define therebetween a mold cavity 60 shaped to conform to the configuration of the article to be cast. Two injector blocks 62, 64 attached respectively to cover die 52 and ejector die 54 permit feeding of the molten metal along the parting line surface, A, between dies 52 and 54. Ejector die injector block 64 includes a tunnel 66 therethrough having one end terminating at aperture 67 in the die block outer wall and joined at the other end to parting line runner cavity 68. Tunnel 66 is surrounded by heating means 70, preferably electric heater cartridges, to keep the metal in the tunnel in the molten state. Parting line runner cavity 68, which connects tunnel 66 with mold cavity 60, is cooled by water flowing in water line 72, or other suitable cooling means, housed in cover die injection block 62 to solidify the metal in the runner cavity 68 while the metal in the tunnel 66 remains molten. The injection system useful with the apparatus of the present invention may be any conventional system,
such as is exemplified and described in connection with FIG. 4, and may include a molten metal melting pot 74 supplying molten metal 75 through nozzle 76 to tunnel 66, parting line runner cavity 68 and mold cavity 60 by the reciprocating action of a piston means 78.
The operation of apparatus 50 will be readily understood from the following description. FIG. 1 illustrates the apparatus after molten metal, such as zinc, has been injected by piston means 78 through nozzle 76 into tunnel 66, parting line runner cavity 68 and mold cavity 60, i.e., along horizontally oriented parting line surface A, and has solidified. It can be seen that apparatus 50 also includes an ejector assembly 80 for ejecting the cast article 100 from the apparatus when .cover die 56 and ejector die 54 are separated. While any well known ejector assembly may be utilized which does not interfere with the parting line metal feed, a simple ejector assembly, as shown, including ejector pins 82, 84, 86 slidably housed within and relatively movable with respect to ejector die 54 in a direction generally perpendicular to parting line surface A is preferred. During casting, the ends of pins 82, 84 communicate with mold cavity 60 and form a continuous planar surface with at least one wall thereof. Likewise, during casting, the end of pin 86 communicates with runner cavity 68 and forms a continuous planar surface with the wall of the ejector die adjacent the parting line runner cavity.
As the die apparatus begins to open, i.e., cover die 52 vertically separates from ejector die 54, see FIG. 2, an undercut portion 88 of cover die ejector block 62 engages the end of the runner 102 and causes it to bend upwardly as cover die 52 moves upwardly. As the runner 102 bends upwardly the molten metal in inclined tunnel 66 runs back down into melting pot 74 to be reused. The end of runner 102 engaged by undercut 88 will continue to bend upwardly as cover die 52 moves upwardly until the restraining force exerted by ejector die 54 is sufficient to pull the runner end out of the cover die.
Finally, after the die apparatus is fully opened, the ejector means is actuated in any suitable manner, e.g., mechanically, hydraulically, pneumatically, electrically or the like, to cause ejector pins 82, 84, 86 to slide inwardly a predetermined distance (for example as may be limited by ejector plate 90 to which the ejector pins are connected and thereby to separate the cast article 100 and bent runner 102 attached thereto from the face of mold section 58b and the adjacent surfaces of ejector die 54 and ejector die injection block 64 (see FIG. 3).
While the present invention has been described with reference to particular embodiments thereof it will be understood that numerous modifications may be made by those skilled in the art without actually departing from the scope of the invention. Accordingly, all modifications and equivalents may be resorted to which fall within the scope of the invention as claimed.
What is claimed as new is as follows:
I. In a die casting machine having relatively movable dies defining therebetween a cavity in which the casting is formed, an opening in the outer surface of one of said dies for injection therein of molten casting metal and conduit means communicating with said cavity and said opening, said conduit means forming a substantially straight-line path for the molten metal between said opening and said cavity, said conduit means extending along the parting line surface between said dies, said conduit means comprising a first portion extending from said cavity along the parting line surface between said dies and a second portion extending between said opening and said first portion heating means adjacent said second portion of said conduit for maintaining the metal therein in a molten state, cooling means adjacent said first portion of said conduit means for solidifying the molten metal therein, and means for bending the solidified metal in said first portion away from the molten metal in said second portion of said conduit means.
2. In a die casting machine having upper and lower dies relatively movable between open and closed positions and defining therebetween when closed a cavity in which a casting is formed, an'opening in the outer. surface of said lower die for injection therein of molten casting metal, conduit means communicating with said cavity and said opening, said conduit means having a first portion thereof extending horizontally from said cavity along the horizontally oriented parting line surface between said upper andlower dies and a second portion thereof extending substantially horizontally between said opening and said first portion, heating means in said lower die adjacent said second portion of said conduit means for maintaining the metal therein in a molten state and cooling means in said upper die adjacent said first portion of said conduit means for solidifying the molten metal therein, the end of said first portion of said conduit means remote from said cavity extending into an undercut in said upper die whereby the solidified metal in said first portion engages with upper die and is bent upwardly thereby upon opening of said die.
3. A machine, as claimed in claim 2, wherein said second portion of said conduit means inclines downwardly from the horizontal from said first portion to said opening.
4. A machine, as claimed in claim 2, wherein said heating means comprises electric heating means, said cooling means comprising a conduit in which a cooling medium circulates, and means for ejecting the finished casting from the open dies, including ejection pins slidably movable in said lower die.
5. In a die casting machine having relatively movable dies defining therebetween a cavity in which the casting is formed, an opening in the outer surface of one of said dies for injection therein of molten casting metal and conduit means communicating with said cavity and said opening, said conduit means forming a substantially straight-line path along the parting line surface between said dies for the molten metal between said opening and said cavity, said dies are upper and lower dies relatively movable between open and closed positions and define therebetween, when closed, a cavity in which a casting is formed, said opening being in the outer surface of said lowerdie for injection therein of molten casting metal, said conduit means having a first portion thereof extending horizontally from said cavity along the horizontally oriented parting line surface between said upper and lower dies and a second portion thereofextending substantially horizontally between said opening and said first portion, and further including heating means in said lower die adjacent said second portion of said conduit means for maintaining the metal therein in a molten state and cooling means in said upper die adjacent said first portion of said conduit means for solidifying the molten metal therein, and an undercut in said upper die in communication with the end of said first portion of said conduit means remote from said cavity whereby the solidified metal in said first portion engages said upper die and is bent upwardly thereby upon opening of said dies.