US2515060A - Divided suction mold - Google Patents

Description

July 11, 1950 A. E. SMITH 2,515,060

DIVIDED SUCTION MOLD Filed Sept. 27. 1946 Patented July 11, 1950 O FF l DIVDED SUCTIION MOLD f Arthur Edgar' Smith, Darlinglointlsydnem New South.- Wales', Australia Application September 27, 1946; Serial No. 6992735 In Australia- September 29, 1945 2 claims. (o1, 224-73) ThisA invention. relates to improvements: irr and connectedy with. divided suction moulds; and. refers particularly but is not limited to moulds. for use in. the formation of. chilled metalv castings.

In the specification of my prior application Se- Y No. 496,496,y now. matured into- Patent No. 2,448,632, there is described divided suction moulds for the purpose referred to and the` pres;- ent invention: relates; primarily to improvements in such moulds.. v f

The .mould described in the aforesaid specilication comprises two. hingedly connected elongated sections which, when closed, abuty against each other in a plane which passes. through a. mould cavity which-.is-.formed partly in one. of the sections. and partly inthe. other. The. meeting faces of .the mould. sections .are provided on opposite. sides. of the cavity with longitudinally extending mating grooves which. accommodate suction tubes adapted to be .placed in communica:- tion` with a source of reduced pressure whereby the mould cavity maybe eyacuatedthroughnarrowV slitsfV formed by .and between. ther meeting faces. of. the mound sections inwardly of .said suction tubes. One end of the mould cavity isccon.- nected by a .passagewith a suctionnozzle through which molten metal .is .drawn tothe mould. from a'suitable receptacle.

The aforesaid prior invention also includes meansv for :supporting a. core centrally within the mould cavity and for parting the casting from the. mould when. the sections of. the latterV `are opened.. Such means include a supporting; plate slidably mounted inthe mould body above the mould cavity ,and having. lost motion means connecting same to the. mould sections whereby the centre `of such plate is, .arranged midway between the mould. sections When the latter :are fully opened.

Now it has been found that when the mould cavity is formed directly in :the hingedlyconnected sections of the mould body as above -described, the said sections, which are necessarily subject to highA and fluctuating temperatures, are liable to warp to an extent which may preclude effective sealing of the joints therebetween'when the-sections are closed, and one object of this .-invention is to provide lan improved. construction -whereby this disadvantage will lbe obviatedr or minimised. Another specific object .lis to provide improved means for separating from .the .mould sections thecastings formed therein.

With these and other objects in View. one broad feature of ythe 'inventionresides ina divided suction. mould comprising a-.plural-ity of yto@ acting body sections, a mould insert accomin dated in one at least of said body sections. and having: ameuld cavity therein and; means securing; said mould insert to. thexresnective body sncf.L tion in such. a mannerrthatsaid mouldinsertis 1fsree'to expand. independently .of said bodyl secr ion..

Preferably: each ofA said.;y mouldy sectionsl is. prof .vided with. a. mould; insert` as.. described, and. one Off saidinserts;mayalso be. movable in opposition to resilient. means and at right angles to.v the plane. of closure whereby suitable. portions. of the mating. faces ofthe: coacting inserts are. mains tained in contact Whenthe. *mould*` sections. are closed.A For this.J purpose...the` inner face. of .the resilientlymounted insert.:y preferably projects somewhat beyond; the corresponding.. face of the correspondingmould. section. when the. mould is open.` Furthermore. the. inner face .of .at vleast .one of; the, inserts. preferably provided. with slightly raised contact ffaces which ensure .that narrw; Suction slits are formedy by andiv between the inner facesof the; inserts. when the mouldfis closed;

Another feature. of. the invention resides inthe provisionpin an upper portion; :of .the mould of .a Slidable extractor plate .arranged and y.zperated in a manner similar: to the. aforesaid .slidable supporting platedescribed in theaforesaid prior specification.. such. .extractor lplate being .adapted te ysupport .a split: boss. or 4.other member communicates with the upper end .of the mould ,cavityy wherebrthe casting formedy .in the. latter willl lextend to. andzbecome.- attached to. said boss. Thus, lWlfien the. mould is opened, the ,casting is supported :centrallyl :between thesections thereof.-

AlternativelyA the .castings mayy he, ejected by laterally slidable ejector pins as. hereinafter de, scribed.A

.For a; :more 'particu-lar y.descri-ption-f .the invention reference Will be made tothe accompanying .drawings in which:

Figure lis a view in- Vverticalfsection of a -di- `vided mould 1in Aaccordance with 4the invention, the planeof the'section being coincident withk the planeof division betweenthe mould sections;

vFigure luis. a'viewin elevation of the cast produced in the mouiishown 'in Figure 1..

Figure 2 is .a view ,-in..-sectional side .elevation Vand is. taken onthe line 2-.-2 of Figure 1. y'

y Figure 3 is a view .in .sectional `plan and is takenfontheline 3-23-.0fF-*`gkl1e-2. .Y

.Fgurexfl is .a view in sectional .plan and risataken l the molten metal.

` suction nozzle.A

alternative ejecting means, and

Figure, 8 is aview in. sectional plan, and is taken on the line 8-8 of Figure 7.

The mould shown in Figures 1 to 6 comprises two hingedly connected elongated body sections I and I0', each 0f which may be of semi-circular form in cross-section as shown and the inner or mating faces thereof are formed adjacent their opposite edges with coacting longitudinally extending semi-circular grooves, eachV coacting pair of which accommodates, when the body secv tions are closed, a corresponding suction tube I3 provided at intervals with slits or exhaust openings I4. The suction tubes I3 are suitably retained to one of the body sections I0 as by means of pins I3.

cate with suction passages I5 in the sections I6 i and I6 of a divided mould head which is formed 4 extend through clearance holes 22', and the insert is capable of undergoing a limiting sliding movement thereon, i. e. at right angles to the plane of the inner face of the insert. The set screws 2I' are restrained against movement by lock screws 23.

The mould insert I8' is urged outwardly from the corresponding body section and towards the other half of the mould by any suitable means,-

and preferably by a plurality of laterally arranged vpairs of pressure pins 24 which extend radially through the wall of the body section I0 and bear at their inner ends against the outer peripheral surface of the insert, the said pressure pins of each pair being arranged on opposite sides of that radius which is normal to the closing Y, plane of the) mould sections as shown.

l Y The upper ends of the suction tubes communiintegrally with or secured rigidly to the corresponding body sections I0 and I0', and the head i mould when closed embracesthe lower end of a suction head II. The sections I'I and I'I of a divided suction nozzle are likewise formed integrally with or are suitably secured to the lower ends of the corresponding body sections, and the suction tubes I3 may be continued therein as The inner face of each body section is formed i centrally with a longitudinally disposed recess v mould.

. Each of said semi-circular recesses accommoi dates a corresponding mould insert I8 or I8' which is formed of metal and is of semi-circular 1 shape incross-section, the upper and lower ends of said inserts being spaced a small distance from in the respective mouldusection as shown at I2 i whereby said insertsA may undergo longitudinal thermal expansion independently of the body sections when the inserts are heated by contact with Each of the mould inserts is formed in its exi posed inner face with a portion of a mouldcavity whereby when the mould is closed thesecavities coact to form a single cavity I-S'corresponding in shape and size to the castings to be formed, and the lower end ofsuch cavity communicates by an extension thereof with a suction passage 20 in the aforesaid sections I'I. and II' of the divided opposite sides of the mould cavity therein. These set screws' extend through clearance holes 22'in the insert whereby the' latteris securely retained to the said body-mould vsectionV while'at the same timefthermal expansion of said mould insert relatively to the bodysection is-freely permitted;

The other mould insert I8 isrsimilarly retained to the body sectionl. :byset screwsy 2l Awhich thezadjacent ends of the corresponding recesses i The outer ends of each pair of radial pressure pins 24 project outwardly from the body section and abut against the opposite ends of a corresponding transversely disposed atresilient plate 25 which is supported at itsvcentre by a screw 2B secured to the said body section. Thus each coasting pair of radial pressure pins 24 tends to project the laterally movable insert I8" from the body section I0' but the maximum movement permitted by the heads of the set screws 2I1 is small. I 1

Accordingly when the mould is opened, the laterally movable insert I8 is forced outwardly by the pressure pins 24 to the full extent 'of its permitted movement as shown in Figure 5, and in this condition the inner face of said insert projects slightly beyond the inner face of the vbody sec= tion I0 to which it is attached.

During the final stage of the closing movement of the mould however, the thus projected mould insert I8" abuts against the, inner face' of the coacting insert I8 and is forced inwardly ythereby in opposition to the aforesaid resilient projecting means therefor, whereby when the mould! is completely closed, the inner faces of said inserts are resiliently maintained in firm mutual contact. f*-

It is necessary however tov provide narrow slits 2I between the inner faces of the mould inserts I8 and vI8 whereby the mould cavity I9 maybe evacuated through the medium of the longitudinally disposed suction tubes I3 arranged'on op posite sides thereof.

For this purpose at least one of the inserts is provided with a plurality of slightly raised contact faces 28 which abut against the inner face of the coacting insert when the mould is closed. The height of these projections (which may be of the order of about .005) thus determines thevwidth of the slits 21, and the contact faces 28 may conveniently constitute the outer ends of a plurality of suitably. spaced `pins 29 recessed into the face of one of the mould vinserts. f v

The outer longitudinal edges of the inner faces of the mould inserts are preferably bevelled or chamfered as shown at 30 to ensure that the air withdrawal passages are notV obstructed due Ito warping at such. edges, whilevcorresponding air withdrawal slits 3I are formed by and between relieved portions of the mating faces -of the body sections inwardly of the suction tubes I3 'asf described in my aforesaid prior specication.` The bevelled edges 38 of the mould inserts also provide sufficient clearance 3I to permit ofy lateral thermal expansion of the inserts within there-` demone by so connecting the insertsjtojthe respectiveg body sections that the former are free to expand and contract within the" latter,L the difculties heretofore experienced andidueto warping of theL mould.. 'members- Aare substantially obviated. Moreoverthe provision of means i for maintaining-f the.' innen mating facesof Ithe-- mould inserts in'ifresilient'fcontact when` the mould isclosed further` assists in-4 obviating the. aforesaidi difficulties 1 andi ensures that air `withdrawal slits 21 ofi'predeten ined. width aref' formed ther'eb'etween."r 'f i In". use .after thcwmould is -closed'and thelower end of the suction nozzle is dipped into a bath of molten metal, the mould cavity I9 is evacuated through the suction tubes i3. Molten metal thus ascends in the cavity and forms a chilled casting therein of the shape shown in Figure 1a, the various balls comprising the casting being subsequently separated by removing the connecting runners.

When the mould is opened, the casting usually tends to remain in one or other of the mould i inserts, and the invention includes means for ejecting same. 'Thus as shown in Figures 1 to 6, each body section may be tted with one or more radially disposed spring loaded ejector pins 36 which extend slidably through the walls of the body sections lil and Iii' and also through the mould inserts whereby when the mould is closed the inner ends of these ejector pins constitute portions of the surface of the mould cavity I9. When, however, the mould sections are approaching their fully open positions, the outer ends 36 of the ejector pins abut against suitably positioned stops 3l (Figure 6) so that further movements of such pins are arrested. Accordingly during the nal opening movement of the mould halves, the inner ends of the ejector pins are projected from the inner surfaces of the mould cavity whereby the casting is separated from the mould and falls into a suitable receptacle.

Figures 7 and 8 show alternative ejecting means comprising a horizontal supporting plate 32 which is slidably supported within the body sections Il! and I above the mould inserts I8 and I8', such supporting plate being connected to each body section by lost motion means which, as described in my prior specification, may comprise pins 33 engaging arcuate slots 33 in the lower face of the plate whereby when the body sections are fully opened, the said supporting plate is maintained centrally therebetween. The supporting plate 32 is formed centrally with a slot 34 adapted to receive a divider tubular holder 35 or other suitable member, the interior of which communicates freely with the upper end of the mould cavity, and the interior of the holder communicates with the suction tubes through a narrow head space 36.

Thus when a casting is being formed in the mould, molten metal is drawn upwardly into the divided holder 35 so that when the mould is opened the casting is parted from both of the mould inserts and remains suspended midway therebetween, and is readily removable from the slotted plate 32.

I claim:

1. A divided suction mould comprising a body having a pair of separable sections with mating faces, each section having an elongated recess in its inner face whereby when said sections are citsedt said recenseert-gather fen" ng: af suit-- stanti-anw sealed eiengated cavity; an einigem@ mouldiinsertlcomprisinga pair of separable@sec-v mouldinsert-lb'eingaccommodated-ein' said-rece" 'ff inlat1correspo'ndirig-onef of1 said bod-ysections w-i its5p niatin'g faceidisposed# substantially' inithe plane? of the mating-` face off'- tlief-f res-p"ectivebody47 section, sea'cllil' mould? insert sectionbeing slioiterv than thet accommodating recess-l to providef al* clearancei space at ait-Y least? oneA end thereof? headed fasteninglmernber's"disposed substantialI-y at righ-tfr anglesi toltlfre p'laneoitheI- mating Lface'si arid retaining@ eachlmouldf' insertsection f to the' f respectivef body section, each fastening me'rrf'-Y ecuredl-t'o -therespective fsectin of it bodysan 4 extending throughfaclearanc'e li'ole" l the respective mould insgrtg section toe-permit? thernialv expe-nsich@A ofi-l said-insert section independently of the respective body section, coacting stop means permitting limited sliding movements of one of said mould insert sections on said fastening means therefor, spaced resilient means urging said last-mentioned mould insert section outwardly from said accommodating recess to the extent permitted by said coacting stop means, said mould insert sections being formed in their mating faces with co-operating portions of a common mould cavity, the mating faces of said body sections being provided at one end thereof with co-operating portions of a passage which extends from the exterior of said body and communicates with the corresponding end of the mould cavity and through which molten metal may enter said cavity, said mating faces of the body sections being formed on opposite sides of said cavity therein with longitudinally extending grooves which coact to form suction passages when the mould is closed, said mating faces of the body sections being relieved inwardly of said suction passages whereby narrow air withdrawal passages are formed therebetween when the mould is closed, and a plurality of spaced shallow projecting elements on the mating face of at least one of the mould insert sections for engagement with the mating face of the other mould insert section whereby said coacting faces are separated when the mould is closed to form narrow air withdrawal passages therebetween.

2. A divided suction mould comprising a body having a pair of separable sections with mating faces, each section having a recess in its mating face whereby when said sections are closed said recesses together form a substantially sealed cavity, a mould insert comprising a pair of separable sections having mating faces, each section of said mould insert being accommodated in said recess in a corresponding one of said body sections with its mating face disposed substantially in the plane of the mating face of the respective body section, means retaining each mould insert section to the respective body section to permit thermal expansion of said insert sections independently of the respective body sec-v tions and in a direction substantially parallel to the plane of said mating faces, means permitting limited movement of at least one of said mould insert sections relatively to the respective body section and substantially transverse to the plane of the mating faces, a plurality of spaced pressure pins extending slidably through the wall of that body section which accommodates said transversely movable mould insert section, said pressure pins having their inner ends in contact abismo,

7 with said4 mould insert section, and a Yplurality of spaced strip springs secured to the exterior of4 lsaid body section and bearing resiliently against the outer ends of said slidable pressure pins, said mould `insert sections being Aformed in their mating faces -With cooperating portions of a common mould cavitxsaidv body being fr )rmedy with a passage Whichextends from the exterior of said body and communicates with themould cavity and through which moltenmetal may enter said cavity, and, said mating faces of the, body sections being formed with grooves Which co-act to form at least one suction passage when 1 the4 mould is closed and said mating faces of the body sections and mould insert sections being adapted to form when the mould is closed narrow air withdrawal passages which extend from said mould cavity to said suction passage.

ARTHUR EDGAR SMITH.

REFERENCS CITED The following'references are of recordinthe file of this patent: i UNITED STATES PATENTS

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