US1490482A - Mold for annular castings - Google Patents

Description

April 15 1924; 1,490,482

W. J. REARDON MOLD FOR ANNULAR CASTING-E Filed July 9, 1921 3 Sheets-Sheet 1 a 2 62 .lo 10 patented Apr; 15, Ed e.

nears sass treat se sine.

WILLIAM J. REARDON, 015' DETROIT, MICHIGAN, ASSIGNOR, BY MEsNE ASSIGNMENTS,

F CLEVELAND, 9310', A CORPORATIONIGF T0 ALUMINUM MANUFACTURERS, INQ,

DELAWARE.

new not. Iannunaa' enemas.

Application flledluly a;

' of Detroit, county of Wayne, State of Michigan, have invented certain new and useful Improvementsin Molds for Annular Castings, of which the following is a specification. j

This invention relates to molds for making annular castings and particularly ringshaped gear castings having gear teeth formed on the periphery thereof.

One object of the invention is to provide a mold for making annular castings having a plurality of projections extending from the main body of t e casting.

Another objectflis to provide a mold for making ring-shaped gear castings having gear teeth cast on the periphery thereof. i

Another object is -to devise anew and improved torm of gate for use in molds for making'annular castings.

Another object is to provide a metal mold for making annular castings in which the molten metal may be subjected to pressure during solidification.

Another object is to devise a new and improved process of making annular castings comprising the application of pressure to the molten metal in the riser cavities. during solidification.

Other objectsvwill be'pointed out in the "following description of certain practical embodiments of my invention.

'a part of this specification "on line 33 of Fig. 2 looking upward, the

side mold sections appearing in section;

Fig. '5 isw a top plan view of a modified formof mold; I

Fig. 6 is a cross-section taken on line 6-6 of Fig. 4;

"Fig. 7 is a cross-section of the casting In the drawings attached to and forming.

1921. Serial 270. 488,554.

and gate metal taken on line 77 of Fig. 3; and

Fig. 8 is a fragmentary plan-view of the casting with gate metal attached.

In Figures 1, 2 and 3 which illustrate a preferred form of mold for making annular gear castings having gear teeth on the exterior edge, 1 designates a mold base, having a centrally disposed circular opening 1*' adapted, to seat a plate 2.

Arranged on the top of base 1 are a plurality of curved side sections 3 which form a complete circleabout plate 2 and which are held in assembled position by a continuous ring 4 having a depending flange 4 provided with an inclined inner surface 4 to engage with the outer side surfaces 3* of the sections 3.

A core, 5, preferably composed of metal, is of suitable size to pass thru the ring d and closely engage therewith. It is mounted upon and supported by plate 2.

-Riser and casting cavities are provided by suitably recessing surfaces of the mold parts. Casting cavity 6 is formed by re cesses in the inner side faces of side mold sections 3 and in the adjacent exterior side surfaces and-meeting faces of core'5 and.

plate 2. Riser cavities 7 are formed by longitudinal grooves 7? in the outer side surface of core 5.

The gate by which molten metal is led into the casting cavity consists of a gate 8 extending vertically downward thru core 5, terminating in a cup-shaped recess 9 in plate 2 and a runner 1O connecting gate 8 with casting cavity 6. Runner 10 is formed by recesses in the meeting faces of core, 5 and plate 2 and comprises a plurality of radially and circumferentially extending passages alternately arranged and located in a substantially horizontal plane. Leading out radially from gate 8 is a plurality of passages 1O which connect with a circumferentially extending passage 10*.

From passage 10 and intermediatethe outlets of passages 10*,a plurality of passages 10 extend radially outward and enter a second circumferentially extending passage 10. Intermediate the'outlets of passages 10, a plurality of radially extending,

passages 10 connect passage 10 with the casting cavity. It will be noted that passage 10 is somewhat larger in cross-section than passages 10 and since its center is located in the same horizontal plane as the centers of these passages, its upper surface lies in a higher plane than those passages and a circular pocket is thus formed which serves to skim ofi' impurities from the molten metal. Similarly passage 1O is also adapted to collect impurities since passages 10 are smaller and formed wholly in plate 2.

It will further be noted that passages 10* are small as compared with other parts of runner 10 or casting cavity 6, and that the molten metal .will tend to solidify in such passages first due to the small cross-section of the passage and the high heat conducting capacity of the mold and core adjacent thereto. It will of course be understood that the usual practice of heating a permanent or metal mold somewhat before attempting to make castin s therein is followed with this mold, an the temperature of the mold and core is brought to a point which will not cause chilling or setting of the molten metal until the casting and riser cavities have been filled. I

A device for exertin pressure on the metal in the riser cavities 7 is disignated generally by 11. It consists of a ring 12 having depending fingers 13 of a size adapted to enter, with small clearance, grooves 7 in core 5, and to project into riser cavities 7.

Means are provided for connecting ring 12 to any suitable apparatus which is capable of transmitting reciprocating motion thereto. In the apparatus illustrated, such means consist of a circular sheet metal member 14 secured at its lower edge to ring 12 and at its upper edge to a ring 15 which is provided with holes 16, properly spaced to receive bolts on the reciprocating head of a power press (not shown). Portions of member 14 are cut away as indicated at 17 to permit attachment of the press head bolts to ring 15 and also to provide openings thru which metal carrying trough 18 may project to conduct molten metal into gate *8.

After ring 12 has been placed in position around core 5, a ring 19 is threaded onto the upper end of the core. This ring, having an outside diameter greater than the inside-diameter of ring 12, acts as a stop in the upward movement of ring 12 and serves as a means by which apparatus 11 may lift core 5 out of the mold.

In operating the described form of mold,

the plate 2 is positioned in opening 1 in base 1. Side sections 3 are assembled about plate 2 and clamped in place by ring 4. Core 5 is lowered thru ring 4 and seated upon plate 2. Ring 12, with members 14 and 15 attached qts fitted around core 5 aneo iea and against displacement by ring 19. Rin 15 is then attached to the reciprocating head of the press and elevated until ring 12 contacts with ring 19. The trough 18 is then inserted thru opening 17 in member 14:. Molten metal poured into trough 18 is delivered to gate 8 from which it passes thru runners 1O into the casting cavity 6 and risers 7. Pouring is continued until the risers are filled, then trough 18 is removed. Immediately after filling the mold, or as soon thereafter as the metal in runner passages 10 has solidified, the ring 12 is pressed downward, pushing fingers 13 into the riser cavities and forcing the still molten metal contained therein back into the casting cavity where, due to the stoppage of passages 1O by solidified metal, it remains under compression until solidification is complete. In this manner, dense, substantially nonporous castings are obtained. After solidification of the casting, ring 12 is elevated into contact with ring 19 and then it lifts core 5 out of the mold. The casting with gate and runner metal attached remains behind in the mold, all parts of the core, including gate 8, having sufficient draft to be freely separated from the casting.

Ring 4: is next lifted upwardly away from side sections 3 and after the latter are disengaged from the casting, it may be removed. Reassembly of the mold and the making of another casting is then merely a repetition of the foregoing described operations.

The gate and runner configuration is especially to be noted. Gate 8, being centrally located in the core, insures delivery of metal at substantially uniform temperature and in equal amounts and at equal velocities to all parts of the casting cavity. Cup-shaped depression 9 tends to prevent splashing of the first entering metal. Runner passages 10 and, 10", each having a greater cross sectional'area than the adjacent exteriorly located passages 10 and 10, respectively, and also having the top,

of passages 10 and 10 located substantially above the outlets 10 and 10*. form Skimmers or pockets in which light im purities floating on the surface of the molten metal may be trapped and prevented from entering the casting cavity and contaminating the metal of the casting.

As an aid in bringing light impurities to the top of the metal from which they can be skimmed by passages 10 and 10, the outlets from these passages are located between the inlets thereto, thus causing the metal to be interrupted in its flow and to traverse a circuitous, abruptly changing. course which agitates the metal and gives all light impurities entrapped therein, an opportunity to rise to the surface. A direct incense smaller cavities can be utilized and also" that the. metal can be forced back into the casting cavity without danger of contaminating the casting.

A modified form of mold is shown in Figs. and 6 where base 21, plate 22 seated in opening of base 21, and side sections 23 are practically the same as the corresponding parts in the preferred form of mold just described. The chief differences between the two molds is the substitution of a sand core for the permanent core and elimination of the positive pressure mechanimn.

The side sections 23 are wedged into close fitting engagement by ring 24. The core 25, in this case, consists of twoparts, a dry sand core 25 resting on plate 22 and a green sand core 25 supported on sections 23 by flask 25 and positioned by lugs and pins 25. g

Casting, riser, gate and runner cavities 26, 27, 28 and 30 are similar in practically all respects to the corresponding cavities in the preferred form of mold. Risers 27 are, however, much larger than risers 7 to provide molten metal for -.feeding by gravity into the casting cavity as the metal therein solidifies.

The manner of assembling the parts of this mold is the same as in the preferred form of mold and the making of the casting difiers from the other method onl in not applying force or pressure, other t an that of gravity, to the metal in the casting and riser cavities. The casting is removed from the mold by lifting flask 25 ofi, and withdrawing sections 23 after they have been .freed "from the wedging action of ring 24t.

Altho I have described two modifications of my invention in detail, I have done so merely for purposes of illustration and do not wish to have the scope of my invention limited to such details. Various changes in the configuration and co-relation of parts will doubtless occur to those skilled in the i said base, core and side members being suitably recessed to form runner, riser and casting cavities, a gate extending thru the core communicatin with the said runner, and a plurality of p ungers adapted to enter the riser cavities and to exert pressure upon molten metal contained therein.

'- 2. The methodpt making annular castings which comprises leading molten metal into a casting cavity thrn runners adapted to separate light impurities from the molten metal, quickly chilling the molten metal in the runners, and then exerting force on the still molten metal in the riser'cavities;

3. The method of making annular castings which comprises leading molten metal thru a gate into the casting and riser cavities of a mold of permanent character, chilling the molten metal, in the gate adjacent the casting cavity, and then subjecting the still molten metal in the'riser and casting cavities to compressive force.

4. The method of making annular castings which comprises leading molten metal into a casting cavity through runners of relatively small cross section. as compared with the casting cavity, filling the casting and riser cavities with molten metal, causing the molten metal in the runners adjacent the casting cavity to solidify while the metal in the casting and riser cavities is still molten, and exerting compressive force on the still molten metal in the riser cavities.

5. The method of making annular castings which comprises leading molten metal into a casting cavity through runners of relatively small cross section as compared with the casting cavity, filling the casting and riser cavities withmolten metal, chilling the molten metal in the runners and causing a stoppage in the runners against back pressure exerted by the molten metal in the casting cavity, and exerting compressive force on the stall'm'olten metal in the riser cavities against the stoppage in the said runners.

6. In a mold for making annular castings in combination, a mold body and a core k cooperating therewith to form riser, casting, and runner cavities, the said runner comprising a plurality of. groups of alternately arranged radially and circumferentially extending horizontal passages, the cross sectional dimensions of the groups ofpassa decreasing progremively toward the casting cavity.

7. In a mold for making annular castings in combination, a mold body and a core cooperating therewith to form riser, casting,

and runner cavities, the said runner comprising a plurality of groups of alternately arranged radially and circumferentially extending horizontal passages 1 ing in substantially the same horizontal p two and the cross sectional dimensions of the groups pf passages decreasing progressively toward the casting cavities.

8. A metal mold comprising a base member including a removable plate, movable sidesections carried on the base member, a flanged ring carried on the top of the side members, and a core carried on the plate of the base member between the side members,

the meeting faces of the base member, the

extending laterally from the inner and out-.

er sides thereof, and means for holding the side members in assembled position with respect to each other comprising an annular inclined surface on the flanged-part of the said ring and similarly inclined outer surfaces of the side members co-operating therewith.

9. A metal mold for casting an annular article comprising a base member, a plurality of side members carried thereon, a ring disposed on top of the said. side members, and a metal core supported by the base Within the said side members and having an upright gate extending vertically therethrough and communicating with the casting cavity, the outer side surfaces of the said side members being inclined to cooperate with a similarly inclined annular surface on one of the mold parts to hold the side-members in assembled position on the mold base, the meeting faces of the several side members and core being recessed to form the walls of a casting cavity.

10. A metal mold for making an annular casting-comprising a base member, a plurality of side members supported on the base member and havirfg inclined outer surfaces andrecessed inner surfaces adapted to serve as the outer side walls of a casting cavity for an annular casting, a metal core disposed on the base inside the said side members when the latter are in assembled position on the base and forming certain of the interior walls of the casting cavity, the said core having a central upright gate extending therethrough, and means for bringing into and maintaining the side members in' assembled relation with each other, including an annular inclined metal surface on a mold part adapted to engage the inclined outer surfaces of the said side members.

In testimonv whereof I affix my signature.

WILLIAM J ,REARDON.

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