US 3584345 A
Description (OCR text may contain errors)
June 1971 K. P. BEASTROM DIE CASTING APPARATUS 4 Sheets-Sheet 1 Filed De c. 9. 1968 INVENT OR KEITH I? BEAST/70M ATTORNEYS June 15, 1971 K. P. BEASTROM DIE CASTING APPARATUS 4 Sheets-Sheet 2 Filed Dec. 9, 1968 VIII! 1A1! I!!! f/d/ A! r r/// Til INVENTOR KEITH P BEASTROM ATTORNEYS June 15, 1971 P. BEASTROM DIE CASTING APPARATUS 4 Sheets-Sheet 4.
Filed Dec. 9, 1968 KEITH P BEASTROM Y a (flM W iTTORNIJYS nited States US. CI. 1830 17 Claims ABSTRACT OF THE DISCLOSURE A die casting apparatus and method in which the upper mold part is carried by a press head for vertical movement toward and away from an injection cylinder, and the lower mold part is attached to a shear extension for lateral movement between the injection cylinder where molten metal is injected into the closed mold halves and a stripping table where the cast article is removed from the lower mold part. An opening in the shear extension receives the metal residue from the injection cylinder for disposal during such lateral movement of the lower mold part to the stripping table.
BACKGROUND OF THE INVENTION This invention relates generally as indicated to a die casting apparatus and method, and more particularly to certain improvements in previous known casting methods and apparatus for greatly reducing the cycle time between castings.
In the die casting of rotors for electric motors and other articles, the bulk of the cycle time has heretofore been spent in assembling and disassembling the mold parts by hand before and after each casting operation. First the lower mold part was placed on a bottom plate and an arbor with the rotor laminations inserted thereover positioned in the lower mold part, after which the upper mold part was carefully positioned over the top of the arbor and a top plate was placed on the upper mold part. Then molten metal was poured into a well in the casting apparatus and the entire mold assembly was placed over the well for injecting the metal into the mold assembly. After the metal solidified, the entire mold assembly except for the bottom plate was moved laterally to shear the mold assembly from the metal residue in the well and the mold assembly was disassembled. Finally, the metal residue was knocked from the bottom plate and removed from the well, thus completing the cycle. For each article made, the very same steps had to be performed all over again, which placed severe restrictions on the rate of production.
SUMMARY OF THE INVENTION With the foregoing in mind, it is a principal object of this invention to provide a method and apparatus for casting articles in which the cycle time between castings is greatly reduced, whereby the rate of production of the articles may be substantially increased and the unit cost per article reduced.
Another object is to provide such a method and apparatus in which the lower mold part and bottom plate are automatically brought into proper alignment with the injection cylinder before each casting operation and the upper mold part is mounted for vertical movement toward and away from the injection cylinder.
A further object is to provide such a method and apparatus in which the metal residue or slug remaining in the injection cylinder after the casting operation is automatically discarded during movement of the lower mold part away from the injection cylinder.
3,584,345 Patented June 15, 1971 These and other objects of the present invention may be achieved by adjustably mounting the upper mold part to the press head of the casting apparatus for vertical movement therewith, and attaching the lower mold part and bottom plate to the shear assembly for lateral movement toward and away from the injection cylinder. The upper mold part is mounted for limited relative vertical movement with respect to the press head to provide a clearance therebetween during raising of the press head for blowing of flashing from the upper mold part, and the shear assembly has a removable extension which provides a quick-disconnect for the lower mold part. An opening in the shear extension receives the metal residue from the injection cylinder for carrying the same away during lateral movement of the lower mold part to a stripping table where the cast article is stripped from the lower mold part.
To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.
BRIEF DESCRIPTION OF THE DRAWINGS In the annexed drawings:
FIG. 1 is a fragmentary longitudinal section through a preferred form of die casting apparatus constructed in accordance with this invent-ion;
FIG. 2 is a top plan view of the lower portion of the apparatus of FIG. 1 as seen from the plane of the line 22 thereof;
FIG. 3 is a fragmentary side elevation view of the press head and upper mold part as seen from the plane of the line 3-3 of FIG. 1;
FIGS. 47 are schematic diagrams showing the various steps for casting an article using the apparatus of FIGS. 1-3;
FIGS. 8 and 9 are schematic drawings showing a modified form of method and apparatus for casting an article in accordance with the present invention;
FIG. 10 is a top plan view of the well for the apparatus of this invention containing a modified form of piston: and
FIG. 11 is a fragmentary vertical section through the well of FIG. 10, taken on the plane of the line 11-11 thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in detail to the drawings and first especially to FIGS. 1 and 2, there is shown a preferred form of casting apparatus 1 in accordance with this invention, generally consisting of a base 2 in the form of an elevated table having a central opening 3 providing a well 4 for an injection cylinder 5 bolted to the bottom of the table, and a press head 6 suitably mounted above the table 2 for vertical movement toward and away from the well 4. A further opening 9 is provided in the table 2 adjacent the front 10 which is of a diameter somewhat larger than the central opening 3 for a purpose to be explained hereafter.
Located adjacent the rear 11 of the table 2 is a shear assembly 12 including a stationary cylinder 13 having its longitudinal axis parallel to the top surface 14 of the table 2 and in alginment with the centers of the openings 3 and 9 in the table, whereby extension and retraction of the ram 15 associated with the cylinder 13 will cause the ram to move laterally across the table from back to front and return in line with such openings.
Attached to the outer end of the ram is a shear extension 16 which may be a one-half inch thick flat steel plate 17 having a T-slot 18 therethrough adjacent the back edge 19, with a cover plate 20 over the top of the T-slot 1S. Threaded into the outer end of the ram 15 is a bolt 21 having a flat head 22 adapted to be received in the T-slot 18 from the bottom, for providing a quickdisconnect between the ram 15 and extension 16.
Welded to the sides of the extension 16 are a pair of side plates 25 having fiat bottom edges 26 which engage the top of the table 2 on opposite sides of the openings 3 and 9 to provide runners for the extension 16 and maintain a slight clearance between the extension and table top. The forward edge of the shear extension 16 has a semi-circular recess 27 therein which conforms to the curvature of the outer wall 28 of a lower mold part 29 for close mating engagement therewith. Different extensions 16 are used for different size molds. If the extension 16 associated with the ram 15 does not have the proper size recess, it may be readily replaced with another extension simply by lifting the extension 011 the bolt 21 and inserting another extension thereover.
The lower mold part 29 is desirably connected to the extension 16 as by providing two pairs of lugs 30' on the lower mold part 29, one lug of each pair extending over the forward edge 31 of the recess 27 and the other extending below such edge. Each pair of lugs has vertically aligned openings therethrough which are adapted to be brought into alignment with openings in the extension 16 for insertion of flat-headed pins 34 through the aligned openings. By controlling the movements of the ram 15, the lower mold part 29 can be moved into and out of alignment with the well 4, thus eliminating the need for having to move the lower mold part by hand.
An annular opening 36 is provided in the central portion of the extension 16 which has a diameter somewhat greater than the diameter of the well 4 in the table 2 to permit ready receipt of the metal slug which is left in the well after the casting operation, in a manner to be subsequently explained. As an example, the well 4 may have a diameter of eight inches and the opening 36 a diameter of ten inches. The wall 37 of the opening 36 is recessed at 38 adjacent the back edge 19 for mounting of a drag plate 39 therein which has a curvature matching that of the wall of the opening 36. The extension 16 desirably clears the table 2 by approximately 1- /2 inches. If the slug which is ejected from the injection cylinder 5 after the casting operation is of less height than that, it will still be caught by the drag plate 39 which extends downwardly below the extension 16 to within approximately /8 to 4 inch from the table top and pulled along with the extension 16.
Repeated handling of the upper mold part 40 and vent plate 41 is eliminated by suspending these parts from the press head 6. As clearly shown in FIGS. 1 and 3, the press head 6 has an adaptor plate 42 bolted or otherwise secured thereto. The outer peripheral portion 43 of the adaptor plate 42 extends outwardly beyond the press head 6 and contains a plurality of radially extending slots 44 to permit radial adjustment of a plurality of hangers 45 suspended therefrom. Such hangers 45 consist of eye bolts 46 extending through the slots 44 with nuts 47 threadedly engaging the eye bolts 46 on opposite sides of the adaptor plate 42 for releasably locking the hangers 45 against movement, and elongated links 48 hooked to the eyes 49 of the bolts 46 for radial swinging movement of the links 48 over mold pins 50 projecting outwardly from the upper mold part 40. The hangers 45 are desirably of sutficient length to provide approximately one to two inches of clearance between the top of the upper mold part 40 and the vent plate 41 which is secured directly to the adaptor plate 42 when the press head 6 is raised as shown in FIG. 1 so that the flashing which forms because of the vent passages 51 in the vent plate 41 during the casting operation can be blown off using an air house. During downward movement of the press head 6, the clearance between the upper mold part 40 and vent plate 41 is taken up by the links 48 which as apparent from FIG. 3 will permit continued movement of the press head 6 after closing of the mold parts for application of high pressure to the mold parts by the press head.
The configuration of the upper and lower mold parts 40 and 29 will, of course, vary depending upon the desired configuration of the article being cast. In the present case, the article is a rotor for an electric motor comprising a stack of laminations 55 having slots 56 therein in which are to be cast conductor bars 57 (see FIGS. 5-7), with end rings 58 and a series of axially outwardly projecting fins 59 cast on the ends of the laminations. The end rings 58 are formed by providing annular recesses 60 and 61 in the opposed end faces of the lower mold part 29 and upper mold part 40', respectively, whereas the fins 59 are formed by a plurality of circumferentially spaced narrow mold cavities 64 and 65 in the mold parts communicating with the respective annular recesses 60' and 61.
For supporting the stack of laminations 55 on the lower mold part 29, there is provided an arbor 66 having a frusto-conical end 67 which is received in a similarly shaped bore 68 in the lower mold part 29 to center the arbor 66 with respect to the lower mold part. An elongated key 69 on the arbor 66 is received in keyways in the laminations 55 for proper orientation of the lamination slots 56 with respect to each other. The upper end 70 of the arbor 6-6 is also of frnsto-conical shape to assist in aligning the central bore 71 in the upper mold part 40 with the arbor and sliding of the upper mold part onto the arbor for engagement with the stack of laminations during lowering of the press head 6. Limited horizontal movement of the upper mold part 40 is permitted for centering of the upper mold part with respect to the arbor 66 during such downward movement of the press head due to the loose fit of the mold pins 50 in the hanger links 48. A central opening 75 in the vent plate 41 and aligned recess 76 in the adapter plate 42 accommodate the upper end of the arbor 66 when the press is fully closed, as shown in FIG. 5. If more room is needed between the upper mold part and press head, a spacer plate may be inserted between the vent plate and adaptor plate. Of course, the spacer plate would be provided with a suitable opening for receipt of the upper end of the arbor, The lower end of the bore 71 in the upper mold part 40 is counterbored at 77 to accommodate the upper end of the key 69 on the arbor 66 which desirably extends only slightly above the stack of laminations before they are compressed as seen in FIG. 1 and somewhat greater than that after they are compressed by the press head 6 as seen in FIG. 5, thus eliminating the need for having to orient the upper mold part 40 with respect to the key 69 during closing of the mold parts.
When sufficient pressure is applied by the press head 6 to the upper and lower mold parts 40 and 29 and stack of laminations 55 interposed therebetween to withstand the injection pressure, a pressure switch PS on the press head actuates the injection cylinder 5 to cause the injection piston 80 to move upwardly in the well 4 and force the molten metal previously placed therein either by hand or by an automatic feeding device 81 into the lower and upper mold parts 29 and 40 and slots 56 in the laminations 55. An apertured plate 82 attached to the bottom of the lower mold part 29 controls the feed of molten metal into the lower mold part. Walls 83 may enclose the sides and back of the table with a vertically movable door 84 adjacent the front inwardly of the opening 9 which is closed during lowering of the press head 6 to protect the operator against injury from splattering metal during the metal injecting portion of the cycle.
Subsequent to the casting operation, the press head 6 is raised to separate the upper mold part 40 from the rotor and lower mold part 29 which is held against vertical movement by a pair of clamps 85' bolted to the table 2 adjacent the sides of the well 4. One of the clamps is desirably disposed slightly to the rear of the other to provide sufficient room for pouring of the molten metal into the well from one side. Each clamp 85 has a lip portion 86 which extends over the upper edge of the lower mold part 29 to preclude upward movement of the lower mold part. However, there is a slight clearance between the lip portions 36 and lower mold part 29, desirably A inch or less, so as not to interfere with subsequent lateral movement of the lower mold part 29 by extension of the shear ram 15, in a manner to be more fully explained hereafter. The door 84 is desirably automatically raised in response to raising of the press head 6.
Adjacent the forward edge of the table 2 in line with the openings 3 and 9 is a smaller stripping table 90 having a pair of spaced apart side walls 91 between which the lower mold part 29 is adapted to be received when the shear ram is frilly extended. The stripping table 90 may be separate from the table 2 or integral therewith. Projecting inwardly from the side walls 91 are inturned flanges 92 which overlie the upper edge of the lower mold part 29 when resting on the stripping table 90 to permit stripping of the rotor and arbor from the lower mold part with the use of a crane having a cable 93 with a book 94 for attachment to an opening 95 in the upper end of the arbor (see especially FIG. 7). The rotor laminations 55 are supported on the arbor by a shoulder 96 adjacent the lower end 67 of the arbor.
OPERATION Referring now to FIGS. 4 through 7, the operation of the apparatus will be set forth. FIG. 4 shows the position of the apparatus 1 at both the start and end of each cycle of operation, with the shear ram 15 extended to locate the lower mold part 29 on the stripping table 90, and the press head 6 in the raised position supporting the upper mold part 40 vertically above the injection cylinder 5. The initial set up of the apparatus is perhaps most easily achieved by first connecting the lower mold part 29 to the shear extension 16 by inserting the pins 34 through the aligned openings in the l gs and extension 16, respectively; then assembling the arbor 66, laminations 55, and upper mold part in front of the apparatus and centering the entire assembly over the well 4. Now the press head 6 may be lowered to facilitate placement of the hanger links 48 over the mold pins 50 and radial adjustment of the hangers 45 into vertical alignment with the mold pins, after which the hangers are clamped to the press head by tightening the nuts 47. The press head 6 is raised to clear the upper mold part 40 from the arbor 66, after which the shear ram 15 is extended to move the lower mold part 29 to the fully extended position of FIG. 4, thus completing the set up.
With the mold parts positioned as shown in FIG. 4, molten aluminum or other suitable metal such as magnesium is poured into the well 4 using either a hand ladle or an automatic feeding device 81. Before filling the well with metal, the exposed surfaces of the well and inner surfaces of the upper and lower mold parts 40 and 29 may be sprayed with a suitable mold release mixture such as graphite and oil to prevent the metal from adhering to the parts and retard cooling of the metal within the well.
After the well 4 has been filled with molten metal, the automatic cycling of the apparatus may be commenced by actuating a switch to cause retraction of the shear ram 15 for centering of the lower mold part 29 with arbor 66 and laminations supported thereby over the well. Such return movement of the ram 15 actuates a limit switch 95 to cause the press head 6 to lower the upper mold part 40 into engagement with the laminations 55 and apply a high clamping pressure to the mold parts as illustrated in FIG. 5. At the same time, the door 84 is automatically lowered.
When the required clamping pressure is reached, which may be in the order of sixty tons, a pressure switch PS on the press head 6 actuates the injection cylinder 5, causing the piston to move upwardly in the well 4 as shown in FIG. 5 and inject the molten metal into the mold parts 29 and 40 and slots 56 in the laminations 55 through the metering plate. Cooling fluid may be circulated through annular passages 96 in the upper and lower mold parts to prevent overheating by the metal. After a slight pause to give the cast metal time to solidify, for example, 15 seconds, the pressure in the injection cylinder 5 is released and the press head 6 is raised to lift the upper mold part 40 clear of the laminations 55 and arbor 66. During raising of the press head 6, the door 84 is also raised, and when the upper mold part 40 is clear of the arbor 66, the shear assembly 12 is actuated to move the lower mold part 40 and metering plate 82 attached thereto forward of the well 4 as shown in FIG. 6.
The initial forward movement of the lower mold part 29 away from the well 4 shears the lower mold part from the slug S of metal remaining in the well 4 after the injection process along the bottom face of the metering plate 82. As the enlarged opening 36 in the extension 16 comes into alignment with the well 4, the extension 16 engages a limit switch 97 (see FIG. 2) which stops the forward movement of the extension and actuates the injection cylin der 5 to move the piston 80 upwardly until it is flush with the top of the table and the slug S is engaged by the drag plate 39 as shown in phantom lines in FIG. 6. After a slight time delay, forward movement of the extension 16 is continued, dragging with it the slug S. During such continued forward movement, the shear extension 16 passes over the opening 9 in the table 2 through which the slug S drops into a collecting receptacle. The extension 16 finally comes to rest when the lower mold part 29 reaches its original starting position supported by the stripping table against vertical upward movement, and an overhead crane is used to lift the arbor 66 and rotor from the lower mold part 29 as shown in FIG. 7, and lower the rotor to the floor where the rotor is laid on its side and the arbor is tapped out.
Because the shearing action between the lower mold part 29 and slug S occurs along the bottom face of the metering plate 82, the sprues 98 formed by the holes 99 in the metering plate 82 during the casting operation create slight projections 100 on the ends of the lower fins 59 of the rotor. However, the metering plate 82 may be made quite thin, in which event the resulting projections 100 are quite short and do not require removing unless desired.
Alternatively, the projections 100 could be eliminated altogether by providing a pin and slot connection 101 between the lower mold part 29' and metering plate 82 permitting limited relative movement of the lower mold part 29 forward of the metering plate 82 when the ram 15 is initially extended to cause the shearing action to occur between the lower mold part 29 and metering plate 82' as shown in FIG. 8. In that event, the sprues 98 will remain as part of the slug S and after shearing the rotor and lower mold part are moved forward approximately one inch and stopped, and the piston 80 is lowered into the well to permit the sprues 98' to drop back into the well 4 along with the slug S because of the tapering of the apertures 99 in the metering plate.
To facilitate stripping of the slug S from the metering plate 82 a pair of flanges 102 and 103 may be provided on opposite sides of the upper face 104 of the piston 80, such flanges having backsloping sides 105 and 106 for retaining the slug for downward vertical movement with the piston. The sides 105 and 106 converge toward each other from front to rear as shown in FIG. 10 to facilitate easy removal of the slug from the piston when raised above table level upon engagement of the slug by the drag plate 39 which is sufliciently vertically spaced from the table to clear the piston flanges. Continued forward movement of the lower mold part 29 will cause the metering plate 82' to move with it, as before. Next the extension opening 36 is brought into aliginment with the well and the piston is elevated to lift the slug S with sprues 98' connected thereto into the opening 36 as shown in phantom lines in FIG. 9, whereby continued forward movement of the lower mold part will drag the slug with it. Later on, when the ram is retracted to again center the lower mold part over the well 4', there is a slight relative movement between the lower mold part 29 and metering plate 82 in the reverse direction thus to properly orient the metering plate with respect to the lower mold part prior to the next casting operation. Otherwise, the details of construction and operation of the modified apparatus 1' of FIGS. 8 and 9 are substantially identical to the apparatus 1 previously described, and accordingly no further discussion is thought to be necessary.
After the rotor has been removed from the arbor 66, as shown in FIG. 7, a new stack of laminations 55 is placed on the arbor and the arbor is again mounted on the lower mold part as in FIG. 4, ready for another cycle. Before starting the next cycle, however, the flashing which forms between the vent plate 41 and upper mold part 40 during the casting operation is blown off and the mold parts and well are again sprayed with a suitable mold release mixture, and the well or reservoir 4 is filled with molten metal.
From the foregoing, it can now be seen that the casting apparatus of the present invention, once set up, does not require continued handling of the upper and lower mold parts, and provides a relatively simple and eifective means for disposing of the metal slug which is left in the well after each casting operation. In use, it is estimated that the apparatus disclosed herein will reduce the cycle time for each casting by 50% or more. Although the apparatus and method of the present invention are primarily designed for use in the casting of rotors for electric motors, it will be apparent that the same principles are equally applicable in making other articles as Well, and that materials other than metals may be used, such as plastics, for example, which are capable of being injected after melting.
I, therefore, particularly point out and distinctly claim as my invention:
1. A casting apparatus comprising a base containing a well for melted material, a shear assembly including a ram movable across said base in line with said well, a shear extension attached to said ram for movement therewith, means for attaching a mold part to said shear extension for lateral movement into and out of alignment with said well upon actuation of said shear assembly, means for forcing a portion of the melted material from said well into said mold part when in alignment with said well and ejecting the remaining material from said well after such remaining material has solidified and after said mold part has been moved out of alignment with said well, and means associated with said shear extension for dragging the ejected material with said shear extension during movement away from said well.
2. The apparatus of claim 1 wherein said base has an opening therein laterally spaced from said well in the path of movement of said shear extension, said opening being of a diameter greater than the diameter of said well whereby movement of said shear extension over said opening will permit the ejected material to drop through said opening.
3. The apparatus of claim 1 further comprising a stripping table located adjacent the forward edge of said base for supporting said mold part in its outermost position, said stripping table having side walls for receipt of said mold part therebetween, and inturned flanges which overlie the upper edge of said mold part to permit upward stripping of a cast article from said mold part.
4. The apparatus of claim 1 further comprising an apertured metering plate for controlling the feed of melted 8 material from said well into said mold part, said metering plate being attached to the bottom of said mold part for movement therewith, whereby movement of the mold part away from the well after casting causes shearing of the cast article from the solidified material remaining in the well along the bottom face of said metering plate.
5. The apparatus of claim 1 further comprising an apertured meterig plate for controlling the feed of melted material into said mold part from said well, means mounting said metering plate to the bottom of said mold part for limited relative movement of said mold part away from said metering plate after casting for shearing of the cast article from the solidified material remaining in the well along the bottom of said mold part.
6. The apparatus of claim 1 wherein said means associated with said shear extension for dragging the ejected material with said shear extension comprises a drag plate projecting downwardly below said shear extension rearwardly of said mold part for engagement with the ejected material.
7. The apparatus of claim 1 wherein said means associated with said shear assembly for dragging the ejected material with said shear extension comprises an opening in said shear extension rearwardly of said mold part which opening is of a diameter greater than the diameter of said well for receipt of the ejected material therein while said opening is in alignment with said well.
8. The apparatus of claim 1 wherein the forward edge of said shear extension has a semi-circular press which conforms to the curvature of the outer wall of said mold part for close mating engagement therewith.
9. The apparatus of claim 8 wherein said means for attaching said mold part to said shear extension comprises two pairs of lugs projecting from said mold part, each pair of lugs extending on opposite sides of the forward edge of said shear extension and having aligned openings therein which line up with openings in said shear extension, and pins extending through said aligned openings.
10. The apparatus of claim 1 wherein the rear edge of said shear extension has a T-shaped slot with a cover plate over the top, and said ram has a bolt projecting therefrom which is slidably received in said slot from the bottom for providing a quick-disconnect between said shear extension and ram.
11. The apparatus of claim 1 wherein said shear extension comprises a fiat plate having side plates projecting downwardly therefrom which provide runners for maintaining a clearance between said shear extension and the top of said base, the forward edge of said shear extension having a semi-circular recess therein which conforms to the curvature of said mold part, and an opening in said fiat plate rearwardly of said recess of a diameter greater than the diameter of said well.
12. The apparatus of claim 1 further comprising a press head vertically paced above said well, means mounting said press head for vertical movement toward and away from said well, and means for mounting another mold part for vertical movement toward and away from said well.
13. Apparatus for casting an article in a multiple-part mold comprising a base containing a well for melted material, means for mounting an upper mold part for vertical movement toward and away from said well, and means for mounting a lower mold part for lateral movement along said base into and out of alignment with said well, said apparatus further comprising a press head, and means for mounting said press head for vertical movement toward and away from said well for applying clamping presure to said mold parts, said means for mounting said upper mold part for vertical movement comprising an adaptor plate secured to said press head, and hangers suspended from said adaptor plate, the lower ends of said hangers having elongated links attached thereto which are adapted to be swung over mold pins projecting radially outwardly from the sides of said upper mold part for movement of said upper mold part with said press head.
14. The apparatus of claim 13 further comprising a vent plate secured to said adaptor plate between said adaptor plate and upper mold part, said hangers being of sutficient length to provide a clearance between the top of said upper mold part and said vent plate when said press head is raised to permit removal of flashing which forms between said vent plate and upper mold part when metal is forced into the closed mold parts, said links being of a length sufiicient to permit continued downward movement of said press head after closing of the mold parts for application of high pressure to the mold parts by said press head.
15. The apparatus of claim 13 further comprising a vent plate secured to said adaptor plate in between said adaptor plate and upper mold part, said upper mold part having a bore therethrough, and said lower mold part having an arbor projecting upwardly therefrom for receipt in said bore in sad upper mold part to align said upper mold part with respect to said lower mold part.
16. The apparatus of claim 15 further comprising a recess in said adaptor plate in alignment with said bore in said upper mold part for accommodating the upper end of said arbor during movement of said upper mold part toward said lower mold part.
17. The apparatus of claim 15 further comprising a key on said arbor, and a counterbore in said upper mold part for accommodating the upper end of said key.
References Cited UNITED STATES PATENTS I. SPENCER OVERHOLSER, Primary Examiner V. K. RISING, Assistant Examiner US. Cl. X.R.
18-30AR, 30Y, Digest 51, Digest 18; 164Digest 10, 113, 264, 269, 410