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Патент USA US2127534

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Patented Aug. '23,
2,127,534
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MOLDS AND corms
Charles‘ Marshall Saeger, In, Bowmanstown, Pa.
No Drawing. Application January‘ 12, 1929,
_ $61181 N0.’ 332,226
6 Claims.
(Cl- 2?r—188)
-
,
(Granted under the‘act of March 3,1883, as
so, 1928; mo. 0. as?)
'while its vaporizing point
My invention relates to a new and useful meth
- amended April
is so high as to leave
of the water in the mold or core or requires
od of making molds and cores for metal castings. much
that such mold ‘or core be baked su?lciently to
Previously in this’art the hot metal coming in remove such moisture, which baking to the de
' contact with the mold and core surfaces caused _ gree required to remove such moisture produces 5
5 the sand in contact to burn into the adjacent a hard core or mold with’its said liabilities.
surfaces of the metal and produce castings of
To overcome the . foregoing conditions and
rough exterior and interior surfaces, which sur
faces are formed of an integral ?lm of mixed
losses and to thereby and otherwise facilitate and
cheapen the production of molds, cores and cast—
ings therefrom, l have devised a method of mak
- metal and sand. This, as well as the removal of
10 the cores -' and the cleaning of the un-integral a ing such molds and cores which precludes the ‘
sand from the casting, has heretofore been an
aforesaid conditions and losses and contemplates
expensive,laborious and dusty task frequently
the forming of the, molds and core or cores there
requiring the use of pneumatic chisels and other of of sand or any of the other desirable earthy
tools, while‘ in the machining of such‘ castings , materials and to apply upon the surface “of ' such
v15 the integral ?lm of sand and metal is di?icult molds or cores, either or both, a rubber or rub
to machine unless the tool in its ?rst cut-pene ' ber-like material. Said material is applied pref
trates beyond the depth of such ?lm.
erably upon vall surfaces of the'mold and cores
In the prior art many cracked castings have that come in contact with the casting.v
been produced due to hard cores and molds which
Where castings are made of material‘
of the casting
which
acts
is
20 do not crush readily as the metal casting cools,xcasiwhile-heated;»the<.>heat"/
contracts and solidi?es, and such castings/area upon the rubber or rubber-like material'upon the
Aosyin’all foun-‘ adjacent surface of the mold or core-and pre
constant source of . substan
dries but more es ciaiiy n aluminum and kin- . vents the material oflwhich the moldor core is
formed from adhering to or being embedded into 25
dre
'
' A further constant ource or substantial loss
the adjacent surface of the casting.
2? in the prior art of‘ metal casting has resulted
However, when articles are cast in such a mold
from mold and core blows due to the low perme-I or with such cores where heat is not required to
ability of the sand forming such molds and cores. make the cast material ?uid, including such as //
The oxidizing of the surfaces of ‘castings, espe
the class of matdevriaisgwhich are lique?ed or Len-i3‘
QO; cially of the more oxidizing metals, due to con . dered?uid-like in order to cast, thesaid’doated
‘7 tactv with the prior ar/tvmoids‘and cores has many 'surface of the-mold or core prevents or retards
wholly, or in part, the flow of moisture from such
In" the past many -.endeavors have been made ‘casting to the material forming such molds and
very objectionable conditions
andlosses. vSome of these attempts have been to
35 form the molds and cores of green sand, which is
/ ("Ft/6T overcome these
, the ordinary molding sand of commerce, but the
40
liability of such molds and cores'to be washed
in part i'ntothe molten ?owing metal being cast
. prevents, or renders hazardous, their use in many
08885.
a
I
To provide molds and cores of more strength
than possessed by green sand molds and cores,
cores.
The manner of applying the rubber or rubber- 35
like substance or material to the surfaces of the
mold and core, or cores, that such mold may con
tain or require, may be by applying the same to
such surfaces in the form of a powder or in the 40
form of a relatively thin plastic sheet or in the
form of a more or less ?uid paint. Where the
same is so applied in the form of the more or less '
?uid paint, the liquid content of such paint is
,itheretofore has been common practice to em ‘adapted to be absorbed to a moreor- less extent 45
‘body a binder in the sand of , either or all, clay,
45, molasses and water, ?our and water, and oil, and by the material of which the body of the mold or
core is formed, and in so penetrating such body,‘
to indurate such molds-and coresby baking. such ?uid carries withit more or less of the
Such molds and cores have all the aforesaid de- . rubber or rubber-like material, which when dried
fects except the tendency to wash into the ?ow- - acts as a binder or supplemental binder to such 50
formed harder
50 mg molten metal, while the thus
cracking liability of body of the mold or core throughout substantial
molds and cores increase the
ly the extent of such penetration.
_
the castings as well as tend to increase the lia
More or less, of said paint applied upon such
bility of the castings to blow due to the lesser surfaces remain upon such outer surfaces where.
porosity of such molds and cores.
,
>
55 a In ‘the prior art water has been employed as
material employed,
a diluent ofthe active binding of
evaporation and
they. are dried by atmospheric temperature ‘or by 55
, the application thereto
of amoderate heat.
By the term, moderate heat, is intended to be
but- its surface tension, rate
meant only such degree of heat as will dry said
other conditions, are such that it requires sub-v material without otherwise, changing its‘ char
:stantial labor in order to properly mix the same
60 with the constituent material of the mold oncore.
acteristics.
‘
e
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,
80 .
‘
2,127,634
. 2
In this speci?cation where the term “rubber” is
employed it is intended to 1include rubber either as
.51
latex, coagulated rubber, or sap from trees such
as Hevea brazz'lz‘ensis, or from vines or schrubs,
as well as from other kindred vegatation-such‘ as
guayule containing more or lessrubber hydro
carbon. The rubber may be unvulcanized or con
sist of vulcanized soft rubber, and may have been
previously subjected to an elevated temperature.
10
It is to be understood that wherever in this
speci?cation the expression "rubber-like” is used,
it is to include materials which are like rubber in
that they afford substantially the same reaction
as the rubber in or on the core or mold to the
depth of penetration or absorption of the liquid
content of such coating would in such cases afford
an ample binder.
In the binders of the prior art with which water
has been present in the molds or cores or has been
employed as a diluent, it is the theory that, when
the hot metal is cast into or against molds or
cores bonded with such binder, the heat-of the
liquid metal vaporizes the water content-of the
mold or core relatively slowly and fills the cavity of 10
the mold with water vapor which oxidizes the sur-_
face of the metal and which water vapor or gas
tends to prevent the charring of the organic
substances on the mold and core surfaces and
heat of‘the cast metal, and which reaction is thus causes contact of said oxidized surfaces of
15
new and unexpected in this art. It may also in
the cast metal with the uncoated or uninsulated
clude any subtsance, either or both plastic and ‘sand grains, and which results in the fusing,
elastic, that has any of the substantial character
imbedding into, or adherence of said sand to the
istics of rubber, balata, or gutta percha, and may
20 include. any rubber or old scrap rubber, either or surfaces of the casting. This action also leaves
a- substantial oxygen content, residual from the 20
both, that has been subjected to an elevated tem
perature alone vor in the presence of sulphuric air, in the casting-cavity of the mold, which is
being ?lled with .the hot liquid metal, and which
acid or a sulphonic acid or a sulphonyl' halide or
oxygen also promotes oxidation of the metal sur
_ it may also include a substance such as'is an
faces and the removal of said char' from the mold
25 article of commerce under the name “Ther
or core surfaces, thus contributing to said fusing 25
moprene.” Wherever the state of the art permits, of and adherence to the casting surfaces.
.
the terms "rubber” and “rubber-like?’ are con
' In the‘ binder which I employlwith a diluent
structively construable as within the spirit and whose
volatility is substantially‘greatenthan wa
scope of my invention.
'
ter,
and
which contains substantially less Bx'ygem
'30
A number of the foregoing materials come with; ‘ "
thetheoryis ~that\when the hot metal is cast into
in the heat plastic grouping, asv well as within the or against molds or cores bonded with such binder,
rubber isomers grouping.
I
.
the heat of the liquid metal vaporizes said diluent
A number of the forgoing materials, which in; relatively more rapidly and quickly forms a gas
‘wlude the. said material subjected to the action of or vapor which expels or replaces the air content
I 35 sulphuric acid, or a sulphonicacid or-a sulphonyl
halide, and also the stated material “Thermm; of the cavity of such mold, and whichgas or vapor 35
thus formed is in itself more, free from oxygen
prene” fall within the less chemical unsaturation than water vapor. These conditions, namely, the
than rubber grouping. The included material substantial absence of air and the, occupation of i
would also come within the heat plastic as well said cavity by‘ a reducing or non-oxidizing gas.
40 as the rubber isomer groupings. Said included
or vapor, promote the charring of the binder.
materials also embrace a reaction product of rub- . upon the mold or core surfaces, tend to prevent
ber with a sulphonic compound having_the'group- . the removal of such charred coating by oxidation
ing R—-SO2X, in which R represents hydrogen or
‘ an organic radical and X represents chlorine or a
45 hydroxic- or hydroxyl group.
J
Inthis artybinders for the constituents of cores
and molds are recognized compositions of com
merce used in the production of molds and cores
50
for the making of castings of hot metal.
When an additional thickness of outer coating
is desired more than one application of said rub
ber orrubber-like material may be made to such '
orycombustion, and thus preclude the fusion or
adherence of the mold or core particles with or
to the surfaces of the casting.
‘ Upon said conditions in the prior art, and in
my invention, the prior art castings are-formed
in the presence of an oxidizing gas or vapor, while i
in: my invention the castings are formed in the
‘ presence of a non-oxidizing gas or vapor formed
by the combustion of the rubber or rubber-like
50.
coating of the surfaces of the mold or core;
‘surfaces of the mold or core. Successive dryings
My said coating of the surfaces of the molds‘
are required where several coats of such liquid are > and cores, either or both, and their amalgamation
55 applied.
.
>
therewith, in a sense, produces what is-somewhat
_ Any of the class of well-known facing materials analogous to case-hardened in somewhat the
may be added in desirable amounts to the rubber ‘same sense that said term has heretofore been "
or rubber-like material coating, which accom
employed to designate certain treated metals. I
plishes ‘a saving in the amount of the rubber or
Said coating is substantially more or less ini
60 rubber-like material otherwise required to be
pervious to water, and the molds or cores so coat 6.0
ed preferably have substantially no water content,
, Such facing addition tothe coating will also
as
it is desirable for the best results with some
give a smoother surfaceto the casting cast there castings
that such moisture ‘as the same may'con
against- due to the fact that such coating will tain should be that of a ?uid which has substan
used.
'
'
tend to level out the hollows between the grains
. of sand and lessens the rubber or rubber-like con
' tent which would otherwise be required therefor.
The material of which-the mold and its re
quired cores, either or both, is made, which is
70 usually sand or other earthy material, is formed
either of what isyknown as a green sand core, or
sand bonded with any of the heretofore described
binders or others which have been in prior use;
tially more volatility than water and whose vol-1
atilization ‘does not result in the formation of
an oxidizing gas or vapor, and which liquid may
be gasoline, benzol, or other such liquid.
When the casting cast against suchimold or
against such core surfaces is of molten metal 70
it is-the theory that the heat of the metal con
verts the rubber or rubber-like coating into’ a. '
but where vthe mold or core‘ is relatively thin, no - characterized gas, and more or less free carbon,
*binder‘ may be necessary. In such cases, the which forms a film between the surfaces of the
‘casting and of the mold and its core or cores,
2,127,584
into said material more or less of the other in- .
and thereby or otherwise precludes the material
hering to or being imbedded in the surfaces of
.such castings so that. the casting comes from the
gredient or ingredients of said fluid. Such pene
tration causes my said coating to not only adhere
to the surface’to which the same is applied, but
mold substantially clean in the sense of having no
sand-or the like adhering thereto or '"being im
terial comprising said surface to the extent of said
bedded therein. This method lowers the cleaning
penetration.
of said phenomenon.
volatile than water in order that it may readily
evaporate from the material of the mold or core
which it penetrates, as well as from the surface
coating, at the temperature of ‘the place where 20'
said coating is applied, or without the application
of which such mold'and core is formed from ad- -
as well to form a substantial bond with the ma
-
Said added liquid is also a solvent of the soluble
cost of castings, facilitates their machining and
may require less metal to be added to the casting ingredient or ingredients of my said coating so
that when an additional coat or coats thereof is 10
10 for the purpose of machining the sand ?lm.
As'to this lastv named phenomenon, applicant or are ‘applied to a mold or core, such additional
~has not yet been able to learn the agencies which coat or coats render’ fluid the outer ?lm of the
previously dried coating so that the subsequent
produce this end. He has with his ‘associates ac
'
counted for said phenomenon on two.‘ theories coat thereby forms a good bond with the previous
15
either
or both of which may explain the existence coat.
15
' Said'added liquid is also'substantially more
_
~
One of said theories is that the hot surface of
the casting in contact with the rubber impreg
nated sand mold and core forms a gaseous layer
20 adjacent to the hot metal surfaces which prevents
the sand adhering to or being imbedded into the
hot metal surfaces.
'
'
' of any more than moderate heat.
_
This application is a companion to my appli
cation entitled. Method and means for foundry
practice, ?led concurrently herewith, Serial Num 25
ber 332,225. This application embodies a dif
ferent species of the invention disclosed in said
The other theory being that such hot metal in
contact with such rubber-like impregnated sand
25 results in the formation of free carbon which
coats the grains of sand and thereby prevents
'such coated sands from either directly coming in
contact with or being imbedded in the, surface of
the
30
casting.
'
_
.
'
1
companion application.
-
The invention herein described may be manu
factured and used tby-zor for the Government of 30
-
It has. further been found that the grains of
sand forming the mold and the cores that have
had applied-thereto said rubber. or rubber-‘like
the United States._.fojr. governmental purposes
without the ‘payment to me of any royalty there
on or therefor.»
material are, due to the heat of the casting, coat
" ‘
‘As to certain features set forth in the foregoing‘
ed with decomposition products of rubber occa- '
speci?cation see also my copending applications 35
‘ like material, and this condition is believed to'be Serial No. 332,225, ?led January 12,_ 1929, for
the main or contributing factor in rendering Method. and means for foundry practice and
especially the cores to be most readily removed . Serial No. 429,227, ?led February 17, 1930, for
sio‘ned by'the conversion of said rubber or rubbere
Method and means for foundry practice.
'
' Having now so fully described my invention 40
from all castings; whereas in the prior art it
.has been the usual custom of requiring as much
that others skilled in the art may therefrom make
and use the same, ‘what-I claim'and desire to
as a day for the removal ‘of some cores from-a
single casting with the best labor-saving appli
secure ‘by Letters Patent is:
ances.
. In‘ making castings vof oxidizable‘materia'l my '
_
1. In the method of producing molds and cores
for the casting of metal, the steps of forming the 45..
said coating for_ the surfaces of the mold and its ' mold or core of the desired shape, and applying
required cores enables un-oxidized castings to be
produced, the substantially bright,_clean and up. a coating of a rubber substance to the surface or
oxidized surfaces of the metal appearing from the surfaces of such molds and cores adapted to come
'
time the casting‘is taken from the mold; where-' in contact‘ with the casting.‘ V 2. In the method of producing molds and cores ,
as'in the prior art the water or other content of -'
the mold and cores, if any, causes oxidization of for the casting of metal, the steps of applying a
the surfaces ‘of the metal cast there. against and coating of a fluid rubber substance'to the surface
or surfaces of such molds or cores‘ adapted to
come in contact with the casting.
3. 'In the method of producing molds and cores 55
which oxidizing castings are not as good in ap
pearance and otherwise as castings of oxidizable
metal made with my said mold and core. The
55 bright and unoxidized surface, produced by my for the casting of metal,.the steps of applying
a coating of a liquid rubber substance to the
said mold, tends to preserve the casting and to re
tard oxidization thereof. This is of great impor- ‘ surfaces of such molds and cores adapted to come
tance as such castings or portions thereof which ‘in contact with the casting, and drying such
are required to be thin and un?nished as'well as coating.
4. A. mold or core for the casting of metal hay»
with the metalsjthat are more readily oxidizable.
A further accomplishment of my said coating ing a coating, applied after the mold or core is
is that the same avoids substantially all actions or formed, containing rubber.
5. A mold or core for the casting of metal
re-actions detrimental to the casting, or the sur
having
a coating, applied after the mold or core
face thereof, that would otherwise exist if the '
casting were in direct contact with the sand or is formed, containing rubber and a facing maother material of the mold.
‘
Where my coating for the surfaces of molds
and cores is applied as a liquid I employ, with
the other ingredient or ingredients thereof, a ?uid
70 intimately mixed therewith which has a substan
tially lower surface tension than water so that
said liquid will readily penetrate a substantial
distance into the surface of the material com
‘prising the mold or core and thus can}? therewith
terial.
-
6. A composition to be applied to the surface or
surfaces of molds or cores adapted to come in
contact with the casting, said composition con
taining rubber, a liquid solvent of said rubber
having a surface tension substantially less than
water and being substantially more volatile than
water.
we
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70
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