Year: 1886

page_text: I, HARRIS TABOR, of No 111 Liberty street, in the city of New York, county of
New York, and state of New York, United States of America, manufacturer, 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 has reference to the flasks in which the sand is compacted to
form the moulds employed by the foundry-man in making castings, and to the
arrangement of pressing surface by means of which the sand is compacted in
the flask.
I put cross-bars in the flask to serve, as usual, to aid in retaining the sand in
the flask. These cross-bars are usually fixed in the flask, and it becomes difficult
in compacting the sand in the flask to properly compact the sand in under the
cross-bars, and the difficulty is greatly increased when the compacting of the sand
is accomplished by means of a pressing surface urged downward upon the sand by
power. I overcome the difficulty by inserting the cross-bars loosely in the flask.
The cross-bars can be inserted in the flask after the flask has been partially filled
with sand, or the cross-bars can be first placed in the flask but not pushed entirely
downward. The flask is then loosely filled with sand, a portion of which finds its
way under the cross-bars where it becomes loosely compacted. A ramming force
being now applied to the top of the sand compacts the sand, and the same force
acting upon the top of the cross-bars forces them somewhat further downward and
they thus serve in closely compacting the sand which is beneath them.
If, in compacting foundry moulds by machinery, the sand in the flask be pressed
upon by a plain flat surface, an equal pressure will be exerted over the entire top
of the sand in the flask. The pattern over which the sand is being compacted
may present irregularities of depth, and the amount of sand to be compacted will
thus vary in depth, and it follows that a plain flat pressing surface is not adapted
for the proper application of pressure to the sand under such conditions. I arrange
a pressing surface in the form of independent pressing blocks presenting normally
a plain surface, but the blocks are capable of yielding independently so as to
accomodate themselves to inequalities, and thereby evenly compact the sand
which may have various depths over the pattern. In constructing this pressing
surface I employ a group of ramming blocks, and attach them articulately in pairs
to levers, and the levers I attach articulately in pairs to other lovers, and I press

page_text: the entire group by means of this last mentioned lever. The subdivision of the
platen into independent blocks may be carried to any extent desired, dependent
entirely upon the number of levers to be employed. Any individual block may
thus move out of a common plane, and still exert the same downward pressure
upon the sand. Such a pressing surface may be forced downward upon the sand
in the flask in a suitable machine, such, for instance as are commonly employed in
foundries, or the flask with its sand may be forced upward against such pressing
surface.
It is found that the inner walls of the flask present frictional resistance to the
downward movement of the sand, and it, therefore, becomes desirable that the
outer blocks of a group should be arranged to exert a superior ramming power.
This I arrange for by making the marginal blocks with smaller areas and employing
equal levers, or by employing marginal blocks of equal areas with the others, and
shortening the lever ends to which they are attached.
In the accompanying drawing Figure 1 represents a pressing surface formed of
four blocks connected in pairs by levers articulated to the blocks, the pair of levers
- being in turn connected articulately by a cross lever, to the centre of which the
pressing power may be applied, as by means of a piston rod. This figure shows
this group of blocks in perspective, and the sand pressing is to be effected by
the end surface of the blocks. The articulation may be effected by means of
cylindrical pivot joints or by means of ball joints. In figure 1 one of the caps is
omitted from over its ball joint. In this figure there are but four blocks.
In Figure 2 I show, in plan, a pressing surface formed of sixteen blocks, being
practically four of the devices of Figure 1. connected by articulated levers, and
arranged to be pressed by a single rod. It will be noticed in Figure 2 that the
blocks are all of the same area. To secure a superior ramming power by the
marginal blocks these blocks may be reduced in area, or the lever ends by which
they are pressed may be shortened.
Figures 3, 4, and 5 are, respectively, a plan, longitudinal section, and vertical
section, of a flask fitted with loose cross-bars capable of vertical motion within
the flask as previously described. The flask is shown as provided with a sand-
box for use in securing a greater quantity of sand at the first filling. The flask
may be loosely filled with sand up to the top of the sand-box, and the articulated
pressing surface then applied to the top of the sand, thus pressing down the sand
and also the cross-bars. The sand-box may then be removed, and the surplus sand
struck from the top of the flask.
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
1. A flask fitted with vertical movable cross-bars.
2. A pressing surface formed of independent blocks articulately connected by
levers.
3. Increasing the ramming power of the marginal blocks of a group of articulately
connected blocks in the manner described.