Improvements in the Art of Dry-sand Molding.
Year: 1894

page_text: Date of Application, 28th Aug., 1894-Accepted, 13th Oct., 1894
COMPLETE SPECIFICATION.
Improvements in the Art of Dry-sand Molding.
I, WILLIAM CLARK WOOD, of 229 Quincy Street, Brooklyn, New York,
United States of America, Civil Engineer, do hereby declare the nature of this
invention, and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :-
This invention relates primarily to the production of railroad frogs and crossings
as one-part steel castings, without patterns or flasks, but is applicable in part to
the economical production of other castings of steel or iron, for railroad tracks or
for other purposes, where the article to be produced is composed of intersecting
members or portions each of uniform cross-section throughout its length, as in a
railroad frog or crossing.
Heretofore dry-sand molds, apart from their cores, have been made, in common
with green-sand molds, from the loose sand, with the aid of expensive patterns
corresponding in principal proportions and cross-section if not in all dimensions
with the article to be produced, and by means of heavy and expensive flasks with
cross-bars for the cope at least, to provide for handling the latter or the respective
parts of the mold.
In so molding railroad frogs or crossings of cast-steel, the necessity for thoroughly
baking each mold in the flask-parts to eliminate moisture before the mold is used
to receive the molten steel has involved expensive "stoves" of great size to contain
the large flasks, and has rendered the process slow and unsatisfactory because of
the time required to bake the molds and the space required to store the large
patterns and flasks, most of them confined to the production of a single frog or
crossing of one pattern as regards the cross-section or cross-sections of the respective
rails, the angle of intersection, and the curve-radius in the case of curve-crossings
or frogs.
The terms "dry-sand mold" and "dry-sand molding" are used herein to signify
baked or dried molded molds and the art of producing them whether their material
be suitably treated molders' sand or clay or loam.
"
The present invention consists in certain improvements in molding cast-steel
railroad frogs and like castings, and in the art of dry-sand molding more generally
considered, as hereinafter set forth and claimed; the molds being adapted to be
poured even with "cast-steel as soon as they are constructed, all the walls of the
matrical cavity being formed by previously baked mold-parts, and to produce
railroad frogs and crossings preserving the cross-section of the rails of the track,
whatever that may be, so as to be connected with each other and with the adjoining
rails in the same manner and by the same means as those employed at the rail-joints
of the road, and supported upon cross-ties or stringers, with or without chairs, like
the remainder of the track, and with the whole frog or crossing a single casting if
desired; and this without employing any patterns, and without the aid of flasks;
the substitutes for patterns being in the form of light and simple wooden boxes
in which to mold the respective mold-parts, and only a few such boxes being
required for a great variety of frogs and crossings made to correspond with a given
pattern of rail.
Six sheets of drawings accompany this Specification as part thereof.
Figure I of these drawings represents a cross-section through four interlocked
mold-parts, as hereinafter described;
Figs. II and III represent respectively a cross-section and a plan view of a
typical sand-molding box for shaping one of said mold-parts;

page_text: Fig. IV is a plan view of a templet for laying out the mold of a given railroad
frog;
Fig. V is a plan view of the bottom-parts of a frog-mold laid out by means of
said templet; and
Figs. VI to XIV inclusive represent end views of sets of mold-parts, for
railroad frogs or the like, matching in cross-section different standard patterns
of rails.
Like letters of reference indicate corresponding parts in all the figures.
To produce a dry-sand mold, Fig. V, for a given railroad frog, for example,
according to the present invention, produce if not already in stock, one or more
sets of mold-parts A, Fig. I, which jointly form a matrical recess corresponding in
cross-section with the pattern of rail to be connected by the frog. Longitudinal
tongue-and-groove joints 6 insure the correct position of each part relatively to the
others, and serve to resist the lateral displacement of the side parts by the molten
metal in the finished mold.
Each of said mold-parts A is shaped by means of a sand-molding box, Figs. II
and III, of suitable wood, baving a matrical cavity C, Fig. 11, which corresponds
in cross-section with the cross-section of its product, and may conveniently be of
any required length. Each box is composed of a bottom-board C³, side-
boards C2, C3, and end-boards C, C, united by screws so as to be readily
loosened.
The particular box represented by Figs. II and III is adapted to produce the
bottom-part of the set of mold-parts represented by Fig. I, which in turn is
adapted to produce the top of a grooved girder-rail having a high guard for use on
curves. To produce said bottom-part the bottom C', only of the sand-molding box
requires special shaping; the sides C2, C3, as well as the ends C4, C5, being cut
from flat boards. The same is true of the box for shaping the top mold-part A in
all cases illustrated by the accompanying drawings. For shaping the respective
side mold-parts shown in Fig. I the sides as well as the bottom of the sand-molding
box are required to be shaped by a templet or gage. As soon as a mold-part is
shaped in the sand-molding box it is loosened by separating the parts of the box to
a sufficient extent, and is turned out upon a plate, upon which it is carried to the
stove where it is baked until it is thoroughly dry and hard, and is then ready
for use in the construction of any mold for which it may be appropriate.
"7
The particular frog-mold represented by Fig. V is composed of mold-parts of the
pattern represented by Fig. 1, and comprises a section A' for the through run of
the frog, and two sections A2, A3, corresponding respectively with the ends of a
second run crossed by such through run. When one of the runs is curved this is
preferably formed by the through section of the mold, as the mold-parts for the
curved run would require the same specific curve-radius and could most economically
be formed of the required length of the entire frog, while the straight mold-parts
can be more readily mitered and otherwise cut and fitted. Consequently, for
casting a frog for an intersection of straight and curved tracks, the mold-section A¹
would be curved and the sections A2, A3, straight. A curved mold-section is
represented by dotted lines in Fig. V.
In laying out and constructing the mold upon the foundry floor, by means of the
templet, Fig. IV, I proceed as follows:
The proper bottom-part for the mold-section A' having been cut if necessary to
the required length and laid upon the floor, the bar D¹ of the templet is laid on it,
and suitable lengths of the appropriate bottom-part are sawed off at the proper
angle to form the bottoms of the sections A and A³, according to the templet
bar D2, D. Curving said bar D₁ to fit a given curved mold-section A¹ is
represented by dotted lines Fig. IV. (The cross-bars D* of the templet serve
simply as stay and handles.) The templet is then removed, and the matrical
cavities of the respective mold-sections are connected with each other by cutting
through the upper flanges of said bottom-part of the section A¹ those depressions of
the sections A and A which form the tread, and the high guard of that ruu of

page_text: the frog which is cast in said sections A and A³, as represented at e and fin
Fig. V, and by extending across said section A' the ridges of said sections A'
and A³ which form the groove in that run of the frog, as represented at g in
Fig. 5. Such alterations at e and f involve simply cutting operations readily
effected by means of a hand-saw and a file. The ridge extension at g is effected by
cutting a groove across the section A' in line with the ridges of sections A³ and A³
and inserting in said groove a piece of the baked mold-material cut in like manner
to the required shape and proportions and inserted into such groove. After the
bottom mold-parts are completed and reassembled, the side mold-parts of the
through section A¹ may next be put in position followed by those of the sections A*
and A³, and these parts may be mitered together in the same manner as said
bottom-parts. In this case the matrical recesses of said sections A and A³ are cut
through the side mold-parts of the section A', which is readily effected by means
of a hand-saw and a file. The top mold-parts of the respective sections are then
applied mitered together and their matrical recesses connected in like manner, and
are provided with the gate and risers of the mold. The several mold-ends are
then closed by means of stoppers of baked sand or other suitable material; the
mold is secured against the separation of the mold-parts as by covering the
mold with loose sand to a sufficient depth; and the molten metal is then poured.
Frogs or crossings for other intersections of tracks laid with the same pattern of
rail are molded in the same or substantially the same manner; the straight mold-
parts serving in common for all straight mold-sections and the curved mold-parts
for all curved mold-sections of like radii.
Molds for frogs, crossings or other track-castings which can be so molded may
be made with mold-parts as represented by Figs. VI to XIV inclusive, in like
manner, by those skilled in the art, without further description. In forming molds
from the mold-parts represented by said Figs. IX and XI the side-parts of each,
being alike, may be shaped in one and the same sand-molding box. In a mold
made from either set of the mold-parts represented in Figs. X, XII, XIII
and XIV there are but two mold-parts in each mold-section.
Railroad track-castings are in all cases made tread-downward, so as to insure a
sufficient compression of the metal which forms the parts exposed to the
greatest wear.
Where both members of a frog or all the members of a crossing or the like are
straight, four sand-molding boxes at most are all that need be kept in stock to
provide for its reproduction, or for the production of straight sections for molding
other frogs or crossings of the same rail pattern, and the mold-parts themselves
can be kept in a dry place for a long period without becoming impaired by age,
and are sufficiently strong to be readily handled without breaking, while they can
be cut by sawing to any required extent.
Frogs, crossings, or the like, can thus be produced with great economy of time
and labor and at a comparatively low cost, as compared with casting them in
molds the construction of each of which demands a pattern appropriate to
that mold as a whole, and a suitable flask of sufficient dimensions to inclose
such mold.
The use of snap-flasks as heretofore commonly practiced in making certain
castings does not answer the same purposes as the construction and process of
molding above described, because such use does not obviate the construction of
each mold from loose sand, and the employment of a pattern corresponding more or
less fully with the article as a whole to be produced; and it does not meet the
difficulty experienced in constructing large dry-sand molds for railroad frogs and
crossings of cast-steel.
Loam-molding dispenses with patterns and flasks, but does not dispense with the
construction of each mold and practically every part of each mold afresh. Moreover
it is not applicable to the production of track-castings.
I have represented only railroad steel or iron in the drawings, but it will be
apparent that the invention is equally applicable to the molding and casting of

page_text: girder-intersection for architectural structures and for use in bridge-building and
ship-building, and to the production of other like castings.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is ;
1. The improvement in the art of dry-sand molding hereinbefore specified which
consists in forming a mold for a cast-steel railroad frog or the like, without pattern
or flask, by preliminarily shaping and baking separate from each other all those
parts of the mold which form its matrical cavity, and mitering together the
baked mold-parts and completing the matrical cavity at each intersection by
cutting operations.
2. The method of molding railroad frogs and like track-castings which consists
in preliminarily shaping and baking separate from each other mold-parts capable
of use in common to form mold-sections of a given rail pattern, and mitering
together the dry-sand mold-parts so produced and completing the connection of
their matrical recesses by cutting operations, substantially as hereinbefore
specified.
3. The process of molding a railroad-frog or the like without patterns or flask
which consists in preliminarily shaping all those parts of the mold which form the
walls of the matrical cavity in separate and distinct sand-molding boxes, each
appropriate to mold-parts in common of a given shape and dimensions in cross-
section, baking the mold-parts so preliminarily shaped, and mitering together the
baked mold-parts and connecting with each other the matrical cavities of the
respective mold-sections by cutting operations, substantially as hereinbefore
specified.
4. The method of forming dry-sand molds without patterns or flasks which
consists in preliminarily shaping and baking separate mold-parts each of uniform
cross-section from end to end, assembling and cutting such parts to form the mold
excepting its ends, and closing the ends of the mold with stoppers of suitable
material, substantially as herein before specified.
5. The method of molding a railroad frog or crossing which consists in
constructing the mold in three longitudinally divided sections each composed of
dry-sand mold-parts, which jointly form the matrical cavity of the mold, and
bringing said mold-sections to the required angle in relation to each other by means
of a templet, substantially as hereinbefore specified.
Dated this 28th day of August 1894.
ALLISON BROS.,
Agents for the Applicant.