US1759831A - Mold for metallic castings - Google Patents

Description

' May 27, 1930.

I A. L. BOEGEHOLD 1,759,831

MOLD FQOR METALLIC- CASTINGS Filed Aug. 1. i927 gwwmtor @M a Eg /feta! \Patented May 27, 1930 UNITED STATES PATENT OFFICE ALF-RED L. BOEGEHOLD, OF DETROIT, MICHIGAN, ASSIGNOR .TO GENERAL MOTORS 7 RESEARCH CORPORATION, OF DETROIT, MICHIGAN, A CORPORATION OF DELAWARE MOLD r03 METALLIC cAs'rrNGs Application filed August 1,

This invention-relates to metal founding. Its object is to enable articles to be cast from metals that shrink materially while solidifying from a molten condition without the formationof pipes and similar imperfections in the cast article.

The nonferrous metals generally, and even steel, when-cast in a mold tend to shrink while setting and thus produce a central void or pipe. According to this invention molten metal is poured into a distributing basin from which it flows through a plurality of small'a'nd short retarding pencil gates into a reservoir *of relatively large section as compared to "the thickness of the casting, and

from the reservoir fiowsthrough an extended gate directly downward into the mold. Thus the molten metal poured into the mold is allowed to solidify progressively from the bottom up and a reserve supply of fluid metal is maintained immediately above the mold and in communication with the mold through anextended opening from which all voids will be filled as they occur. Permanent molds may be used to advantage. Molds of fine copper associated with means for conveying away the heat are preferred.

Further objects andadvantages of the invent-ion will appear in the course'of the following description, taken in connection with the accompanying drawing and appended claims.

In the drawing: I Figure 1 is an end viewpartly in sectlon, of a portion of a casting apparatus in accordance with this invention. 7 I

Figure 2 is a view of the inside or forming surface of a mold section. I

Figure 3 is a. side view of the mold core support partly broken away. p

y In a device of this character theshape of the mold sections must ofcourse depend on the shape of the casting for which the mold is constructed. 1 haveillustrated-an appa- 1 ratus for casting bronzebearings, this particular embodiment-beingdesigned to form four half bearings at a time,-tho I desire it to beunderstoodthatmyinvention is not limited to any particular shape of casting nor to any 1927. Serial'No. 209,844.

particular metal or alloy which it may be de sired to cast.

The drawing illustrates an apparatus for casting bearings comprising a machine base 10, separable mold sections .and carriers, a separate mold and core support comprising horizontal mold guiding and supporting flanges 11 resting on the base and a central a dividing member 12 provided at each end with flanged core rests 14. A-sand 'core 15 is supported on the upper edge of the central dividing member and the rests 14, the upper side of saidsandcore having a longitudinal dividing ridge 16 which corresponds in thickness to the dividing member 12 and spaces the two parts of the finished bearing castings.

Supported at each side of the dividing member 12 and resting on one flange 11 is a mold section,indicated generally at 18. The mold sections are identical in form'but reversed in position so that one fits on the right hand side of the sand core and the other on the left. The lower part of each mold section has an inner face that fits snugly against the upright face of dividing member 12. The walls of themold or forming cavities of the mold section are spaced from the sand core as illustrated in Figure 1 except at the ends 20 and central part 22. The parts 20 and 22 fit evenly against the sand core, except that they are provided with cavities 3.9, in which ejectinglugs are cast. The forming portions of the moldsections illustrated as surrounding the core between the parts 20 and 22 are grooved internally as illustrated at 23 in order to form circumferential ribs on the particular castings for which this mold is designed. The flanges 14 on the core support fit in chamfered portions 13 on the inner lower surfaces of the mold. sections beyond the mold cavities. V

The mold sections are formed with elongat:

ed complemental cavities which together constitute' a distributing basin extending horizontally substantially the entire length of the forming portions of the mold, and having a depressed central portion; with flar-' ing upper surfaces constituting a trough 28 adapted to prevent slop ing of molten metal being poured; with me an grooves 30 transverse ofthe distributing basin constituting siderably greater diameter in all directions than the thickness of the casting to be formed, said reservoirs extending horizontally substantially the full length of the mold cavities and communicating with the distributing basin by means of a lurality of flow retarding pencil gates 24 ormed by short grooves in the mold sections, and with the mold cavities by an approximately full length opening 25* up into which the dividing ridge 16 of the core extend. Vertical end flanges 21 on the rear faces of each mold section contact with the carriers 34 when the molds are in place. Between the flanges 21 said dissipating flan es 21 may be disposed 'as shown, for examp e, in patent to C. L. Lee 'et al. No.-1,634,152.

A mold carrier 34 is connected to each mold section by means' of bolts 32, the heads of which fit in countersunk holes 33. Apertures 36 r are provided in the mold carriers for hinging them to a mechanism for opening Hand closing the mold'in'any usual or desired manner. The numeral 38 indicates ejector rodsfor releasing the solidified casting. The ejectors are disposed so as to engage lugs formed-in the casting bythe cavities 39. on Three of'these rods for each mold section may be used as shown in the construction illustrated. The slide through holes 41 registering with t e cavities 39'.

Dissipation of the heat is made more rapid during pouring of the metal by passing a blast of cool air up. between the'mold sections 18 and the'mold carriers 34in contact 'with said heat dissipating flanges. Ijhave illustrated for this purpose nozzles 40 which may be connected with a compressed air tank 7 or pump and which may beoperated during the casting operated byany usual or desired.

means. V r

The operation of my device will now be described. With the parts disassembled the sand core 15 is placed in the position 'illus-,

trated in Figure 1: The moldsections are closed to the position illustrated in Figure 7 1 andmolten metal poured into hopper 30 descendsto the central depressed portion of the] distributing basin 26 v7 whence it 'flows laterally in opposite directions the full length A. of the mold cavities. .The fluid*metal d escen'ds Zfrom the distributing basin through the flow retarding pencil gates 24 into and th'rough the'reservoir's 25 into the form ingzcavities surrounding the sand core until these cavities are; filled. When the metal solidifies the mold sections-are separated, the

solid mass removed and the operation repeated. r

The riser passages 31 allow the metal to back up should it be poured faster than pencilga-tes 24 allow it to flow into the mold cavity. They also serve as observation ports permitting the foundryman to observe they progress of the pouring operation. Distributing basin 26 withrelatively small gates 24leadingfromitinto the mold cavity retains the meal and causes its distribution evenly to all parts of the mold at a rate of speed that permits progressive setting of the casting as described. The presence of reservoir 25 between gates 24 and the true mold cavity maintains a reserve supply of molten metal in direct communication with the mold cavity. and provides a sizable-sink head on the casting in which final shrinkage takes place thereby avoiding piping or like defects in the cast object itsel V a v I claim:

1'. A mold having a forming cavity cor responding to the article to be cast; a reservoir immediately above the forming cavity of approximately the same horizontal extent as the forming cavity and communicating with it through an orifice o'fsubstanti'ally equal horizontal extent; a distributing basin communicating with said reservoir through a plurahtyof pencil gates, and a pourm hopper communicating with the distri uting' basin. 7

2. A'mold having a plurality of forming cavities disposed horizontally; a reservoir immediately above each forming cavity of approximately the same horizontal extent as the forming cavity and communicating with it through an orifice of substantially equalv horizontal extent; a distributing basin having two series of relatively short pencil gates communicating with said reservoirs, and a pouring hopper communicatin basin between sa1d series of P611011 gates.

- 3. A moldhaving a plurality of forming cavities disposed horizontally a reservoir im mediately above each formingcavity. of approximately the same horizontal extent as the orming cavity and communicating with it through an orifice of substantially equal horizontal extent; a distributing basin extending horizontally over'said reservoirs and communicating with each reservoir through a- .series of short pencil gates,saidbasin having a de ressed portion'disposedbetween-the gates and a pouring hopper series 0 pencil above the depressed portion of the asin.

4. A mold having a forming cavity ;:a reservoirimmediately-above and of approxi-- mately" the same horizontal extent as the forming cavity and communicating with it. v throughan orifice of substantially equal hori-1 zontal extent; a distributingv basin above the reservoir communicating with said reservoir through a serlesof short pencil gates, sa1d with said rable sections havin of the series of pencil gates,

basin having a depressed portion at one side and a pouring hopper directly above the depressed portion of the basin.

5. A mold having a forming cavity; a reservoir immediately above and of approximately the same horizontal extent as the forming cavity and communicating with it through an orifice of substantially equal horizontal extent; a distributing basin above the reservoir and communicating therewith through a'series of short pencil gates, a pouring hopper communicating with the distributing basin at one side of the series of pencil gates, and a riser passage immediately above the pencil gates.

6. A permanent mold consisting of sepagrooves, and interme iate spaces to receive a core; a core disposed in said spaces, separated portions of the mold being in contact with the core; said mold sections having a main forming cavity surrounding said core between the portions in contact therewith and lug formmg cavities extending from said main forming cavity alongside the I core, and ejectors slidable in said sections through said lug forming cavities.

7. A permanent mold composed of separable sections having oomplemental forming cavities; a core support comprising lateral base flanges upon which the separable sections rest in their closed positions and an upright core supporting member against which the inner faces of the lower portions of the separable sections fit when they are in closed position.

8. A permanent mold com osed of separable sections each having at east two complemental forming cavities adapted to receive molten metal to form one-half of a bearin a core support comprising a longitudina upright member, said mold sections having flat surfaces beneath the forming cavities adapted to fit against the sides of the core support, a core havin a dividing ridge on its upper side supporte on-said core support; said separable sections fitting against the core at each end and between the mold cavities, the latter being formed around the core.

In testimony whereof I afiix my s1 ature. ALFRED L. BOEGEH%) LD.

meeting faces, gate

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