IMPROVEMENTS IN APPARATUS FOR MAKING DRY SAND CORES
Year: 1885

page_text: COMIDELE
SPECIFICATION.
I, HERBERT JOHN ALLISON, of 52 Chancery Lane, London, in the County of
Middlesex, Patent Agent, do hereby declare the nature of my invention for
IMPROVEMENTS IN APPARATUS FOR MAKING DRY SAND CORES," a communication
to me from abroad by James Henry Blessing, of Albany, in the State of New York,
United States of America, Gentleman, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying drawings, forming part of this
specification, in which :-
Figure 1 is a longitudinal section of a core for a globe valve-casing with the wax
model for forming the valve-seat in place;
Figure 2, a like section after the wax model has been melted away;
Figure 3, a side elevation of one-half of the box for making said core, showing
the core partially formed;
.
Figure 4, a like view, showing the core in a more advanced state of completion;
Figure 5, a plan view of the core-box with the destructible seat model fixed in
position;
Figure 6, a front elevation of slide for forming semicylindrical partition in said
valve-casing;
Figures 7 and 8 are, respectively, a plan view and edge view of the destructible
model for the valve-seat;
Figures 9 and 10 are, respectively, a side and edge view of a scraper for removing
the surplus material from the under part of the spherical portion of the core; and
Figure 11, a side elevation and partial section of the print block for finishing the
said under part of the spherical portion of the core.
In making castings with internal parts of irregular or complex forms great
difficulty has heretofore been experienced in forming the cores, as in many cases
the metal is required to be cast into parts of the core that are inaccessible when
the core is made as an entirety; this fact has led to the practice of dividing and
subdividing the core into many parts in order that, the otherwise, inaccessible
places may be reaclied to secure proper formations for the required casting; but
Price 1

page_text: the aforesaid practice has been attended with other difficulties which, in addition
to the increased cost of making suitable core-boxes, have been a source of frequent
loss, for the reason of the liability of these multiplex cores being improperly set in
the moulds even when the work is done by the most skilful men-and of the
liability of their being displaced by the action of the molten metal as it enters the
mould, and in either case the result will be the loss of the casting. These defects
are serious when only a single casting of the above named kind is required, but
when many castings of the same kind are required to be made every day, the
percentage of loss becomes a most important item in the cost of manufacture.
The object of my invention is to remedy these defects by providing a means for
making any intricate core as an entirety, which may be placed in a mould in a
complete and perfect condition for receiving the liquid metal into its most remote
and, apparently, inaccessible openings; and to this end my invention consists in
employing models of wax, or other material that will melt or fuse at a low degree
of heat, to form such spaces in the core as are required to produce in the casting
those interior portions-such as partitions, flanges and other parts-that cannot be
readily formed by means of removable patterns; the said models being retained in
the core until the latter is subjected to sufficient heat-either in the operation of
baking the core, or by pouring the metal into the mould-to melt or fuse the
material of which the model is formed.
As represented in the drawing A is the core for the casting of a globe valve-
casing, consisting of a spherical portion a, and cylindrical stemns a¹, a² and a³; said
stems forming, respectively, the induction, eduction, and bonnetted openings for
said valve-casing; said core also contains the following spaces; a, in which the
upper semicylindrical partition of the casting is formed, 5, for the lower semi-
cylindrical partition, and a for the valve-seat; in the last named space an annular
flange is produced which continuously connects the upper and lower semicylindrical
partitions and forms the valve-seat of the casing.
The destructible model B is preferably made of wax that will melt at a gentle
beat, but having sufficient tenacity to protect it from injury during the operation
of ramming the sand into the core-box. In the sample selected for illustrating my
invention the said 'model is made in the form of an annulus, as shown in Figs. 7,
and 8, but its form may be changed in any way to suit the purpose for which it is
'required.
The core-box for forming the core above described consists of the two corre-
sponding parts C, parted longitudinally, held in position by means of dowel pins c,
and having at its central part a hollow globular portion (for forming the spherical
portion a of the core) from which radiate the cylindrical barrels c¹, c², c³, and c³;
in the first of which is formed the stem a¹, in the second the stem a, and in the
third the stem a³; the barrel c¹ is provided for the purpose of facilitating the
operation of forming the space a³, holding the destructible model B (in the first
stages of making the core), and finishing the lower part of the spherical portion of
the core.
The semicylindrical slides D are fitted to slide into the barrels c³ and c; one
slide being inserted in each barrel so as to lie, relatively, at diametrically opposite
sides, and wherein they join to contracted portions of the bore of said barrels, as
shown in Fig. 5, to form a cylindrical bore of uniform sizé; the inner ends of the
two slides D extend past each other to a distance equal to the thickness of the seat
model: B so that the two semicylindrical partitions, cast in the spaces formed by said
slides, will be flush with the valve-seat at their respective sides; the slides D are
provided with studs; d, which project through slotted openings, c³, in the core-box,
so as to facilitate the removal of said slides, from the core-box, after the core is
formed. The cylindrical plug E is fitted to enter the barrel c' of the core-box, and
is of sufficient length to support the seat model B in its place during the first stages
of forming the core; the inner end of said plug is provided with a concavity for
producing a button head a' of compacted sand (which enters said concavity through
the central opening of the seat model) for the purpose of holding said seat model

page_text: in, place after the plug E is withdrawn. The scraper F is inserted in a cylindrical
stock, f, which is fitted to rotate in the bore of the barrel c'; the blade of said
scraper is designed for the purpose of removing any excessive quantity of sand that
may be rammed into the barrel c', and it is so proportioned that it will leave the
spherical portion a of the core in a nearly finished condition. The print-block G
is fitted to slide into the barrel c, and has in its upper end, a concavity which
conforms to the surface of the spherical portion a of the core; the said print-block
is so proportioned in length that when forced down into place (after the scraper F
has performed its function) it will compress the sand at the lower part of the
spherical portion a of the core, and finish that portion to a perfect spherical
form.
The mode of making cores in the above described core-box is as follows: The
two parts C of the core-box being clamped together, and the slides D, cylindrical
plug E, and destructible model B inserted in their respective places, the core-sand
is rammed into the barrels c² and c³, to form one part of the spherical portion a,
cylindrical stems a² and a³, and the button head a', as shown in Figure 3; the
plug E is then withdrawn and-with the core-box in a reversed position-core-
sand is rammed in to fill the barrel c¹ and partially fill the barrel o, as shown in
Fig. 4, thereby forming the stem al and filling the cavity for the spherical portion a;
by this operation, last described, the core-sand.last introduced becomes incorporated
with that of the button-head a' so that the core will be a complete, unbroken,
body throughout its entire structure; the scraper F is next inserted in the barrel c¹
and by rotating it the surplus of the sand is scraped from the lower part of the
mass for forming the spherical portion a; after this surplusage of sand is emptied
from the barrel c', the print-block G is inserted in said barrel and forced down to
its place to the finish the lower part of the spherical portion a, and complete the
formation of the core, after withdrawing the print-block G, the slides D are drawn
out, and one part C of the core-box is removed; a metallic shell of suitable form
to receive the sides of the core, uncovered by the removed part of the box, and
having in its concavity for receiving the spherical portion of the core, a drainage
hole, for the escape of the melted wax, is placed on the uncovered side of the core,
and the whole is turned over so that the core will lie in the metallic shell; after
which the remaining part of the core-box is removed, leaving the unbaked core
(with the destructible model B in place as shown in Fig. 1) resting in the metallic
case; the latter--and its contained core-is then placed in an oven for the purpose
of baking or drying the core, and in the latter operation, the wax model will be
gradually melted away without disturbing the sand atoms of the core, (the melted
wax will escape through the drainage hole in the metallic shell) and leaving the
required space a for the valve-seat, as shown in Fig. 2.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
A core-box for forming cores of the character herein described, consisting of the
corresponding parts C, semicylindrical slides D and destructible model B; the said
several parts being constructed, combined and arranged, to produce the required
form of said core in the manner substantially as specified.