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Патент USA US2125067

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1-,
July 26, @380
B. F. DAVIDSON ET AL
2,125,057
MEANS F'TR PREVENTING THE ‘ADHERENCE OF MOLTEN METAL TO ANOBJECT
Filed May 29, 1935
'
[N VEN TORS
f DAVIDSON
and GARE/V66 Filo/1m;
A TTORNEY
2,125,067
Patented July 26, 1938
UNITED STATES
'
PATENT ‘OFFICE
2,125,067
MEANS FOR PREVENTING THE ADHERENCE
0F‘ MOLTEN METAL TO AN OBJECT‘
Benjamin F. Davidson and Clarence F. Morse,
Dubuque, Iowa, assignors to Mergenthaler
Linotype Company, a_ corporation of New York
Application May 29, 1935, Serial No. 23,984
3 Claims.
This invention relates to means for prevent
ing the adherence of molten metal to an object,
and especially to means for preventing the ad
herence of molten metal to the plunger rod of
5 machines designed to produce type bars, types,
and like typographical elements.
In the operation of the casting mechanism of
such ‘machines, molten metal contained in a so
called “metal pot” is ejectedtherefrom into a
10 mold by means of a plunger operating in the well
of the pot, this plunger being carried at the lower
end of a plunger rod, usually made of steel, which
extends upwardly through the bath of molten
metal and which is connected above the pot to
15 appropriate power devices operating to recipro
cate the plunger down and up during each slug
casting operation.
During the reciprocation of the plunger, a cen
tral section of the actuating plunger rod is mo
mentarily immersed in the bath of molten metal,
and in practice it has been found that each time
this section is removed from the bath, metal ad
heres to the upper end thereof and that the
metal which thus adheres accumulates and even
(CI. 22-70)
‘ried upwardly into the air where it hardens
about the rod.
'
In accordance with the present invention, the
‘above, as well as other di?iculties, are overcome
by enveloping at least that portion of the plunger :5
rod which is in line with the level of vthe bath
when the plunger is in its down position within a
shield which is so constructed that the vmolten
metal does not adhere thereto as it is alternately
die
carried into and out of contact therewith.
For a clear understanding of the invention, ref
erence may be made to the accompanying draw
‘ing. In the drawing, however, ‘the invention is
shown merely in preferred form and by way of
example, but obviously many changes and vari- 4115
ations may be made therein and in its mode of
application which will be comprised within its
spirit. It should therefore, be ‘understood that
the invention is not limited to any speci?c form
or embodiment, except in so far as such limita->._i20
tions are speci?ed in the claims.
Referring to the drawing:
‘Fig. 1 is an elevational ‘view, partially in sec
tion, of certain portions of a casting machine
tually attains such proportions that in the de
scent of the plunger rod, it strikes the surface of
the bath and causes the same to splash. This
action not only detracts from the efficiency of the
embodying the principles of the present inven-.j225
tion;
slug casting operation, but in addition,‘ the
sociated shield; and
splashed metal is thrown out upon adjacent parts
of the machine and aside from endangering the
operators and others who might be near, it ne
cessitates the stopping of the machine and en
Fig. 3 is a View in section, taken along the linec30
3-3 of Fig. 2.
In the drawing, I0 designates a metal pot with
tails a considerable loss of time in removing the
splashed metal from the machine parts and in
freeing the rod of the accumulated mass of metal.
This accumulation of metal is believed to be
due to the fact that the dissipation of heat by
radiation and by conduction from the exposed
‘ upper end of the rod so reduces its temperature
that the motlen metal is chilled as it is immersed
therein during the casting operation; and to the
further fact that the time this section is im
_ mersed is insufficient to raise its temperature suf
?ciently high to free it of the metal which ad
heres to it as a result of being so chilled.
The
metal, however, which adheres to the rod and
which is carried below the surface of the bath is
J reheated by the bath to temperatures sufficiently
high to free it from the rod but the metal which
so adheres to that portion of the rod which is in
line with the level of the bath when the plunger
is in its down position is not carried below the
level of the bath, but on the contrary it is car
Fig. 2 is an enlarged detail view, partially in
section, of the plunger, plunger rod and‘its as
a well H therein, and having a discharge spout
[2 leading from the well and adapted to deliver
molten metal ‘into a mold IS. The ejection of. 35
the molten metal from the pot is effected by
means of a plunger l5 ‘movable down and up in
the well ll vand operated by a plunger rod H ex
tending upwardly from the plunger through the
bath of molten metal and connected above thevilo
.pot to suitable actuating mechanism, including
a lever l6 adapted vto be operated to move the
plunger down ‘and up in successive slug casting
operations.
In accordance with the present invention the 45
gradual accumulation of metal about the rod
I5 before alluded to, is prevented by means of
a shield II which surrounds and which is heat
insulated from at least that portion of the rod
which is in line with the level of the bath when 50
the plunger I4 is in its down position, the shield
being made of a thin sheet of aluminum or other
suitable metal or alloy having high heat con
ducting properties to render it highly sensitive
to temperature changes. In the present embodi- 55
' 2
2,125,067
ment of the invention the heat insulation is ob
tained by so constructing the central portion of
the shield I1, as shown more clearly in Fig. 2,
as to provide an air pocket [8 between it and
that portion of the rod which it envelopes. If
desired, this air pocket may be packed with
suitable heat insulating material but in the pres
ent embodiment of the invention this is dispensed
with and the insulation offered by the con?ned
10 air in thepocket is relied on alone. The lower
present embodiment of the invention, to simpli
fy the construction of the shield but it is ob
vious that this loss could be substantially elimi
nated by the insertion of an insulating member
between the shoulder and the rod,
Since this gradual decrease in temperature is
slight, the temperature of this portion of the
shield is raised to substantially the temperature
of the bath as it is brought into contact there
with when the plunger is moved to its down 10
end of the shield terminates in a shoulder I9
position, this increase in temperature being due
which ?ts tightly about the rod to seal the lower
primarily to the high degree of response which
end of the air pocket l8 against the in?ow of
molten metal, and to prevent displacement of
the shield has to temperature variations and to
15 the shield, as it is raised and lowered in the
the fact that as the shield is immersed its heat
absorbing area increases and its heat radiating 15
area decreases accordingly. Under these condi
bath, the shoulder I9 is fastened ‘to the rod as
by means of a pin 20. The upper end of the . tions the molten metal is not chilled sui?ciently
shield I‘! likewise terminates in a shoulder 2|v
to cause it to adhere to the shield as the shield
which also ?ts tightly about the rod to seal the is brought into contact therewith during the re
ciprocation of the plunger rod.
20 upper end of the air pocket l8 against the in
20
?ow of ambient atmosphere. In the present em
Having thus described our invention, we claim:
bodiment of the invention the overall length of
1. In combination, a pot containing a bath of
the shield I1 is such that the lower end there
molten metal, a reciprocable plunger rod so
of remains immersed in the bath when the
positioned in the pot that a section thereof is
25 plunger I4 is in its raised, position as indicated alternately carried below and above the level of 25
by the full lines in Fig. 1, and the upper end the bath, and a metal shield carried by said rod,
thereof remains above the level of the bath when insulated from said section by con?ned air and of
the plunger is in its down position, as indicated such length that the lower end thereof remains
by the dotted lines in the same ?gure.
immersed in said bath and the upper end there
The lower portion of the shield, being im
of remains above‘the level of the bath as the rod V30
30
is reciprocated.
mersed, even when the plunger I4 is in its nor
mal raised position, absorbs heat from the bath
2. In a typographical machine, the combina
as well as from the immersed lower end of the tion of a pot containing a bath of molten metal,
plunger rod 15 and is, therefore, maintained at a reciprocable plunger rod so positioned in the
pot that a section thereof is alternately carried
35 a temperature substantially the same as the tem~
perature of the bath, but the upper portion of below and above the level of the bath as the rod
the shield, being exposed to the ambient at
mosphere, loses heat by radiation as well as by
conduction through the upper shoulder 2| to the
40 rod l5 and is, therefore, at a temperature which
gradually decreases from that portion which is
in line with the level of the bath and which is
at a temperature substantially the same as the
temperature of the bath to the upper end there
45 of.
This gradual decrease in temperature, how
ever, is slight, due to the high heat conducting
properties of the shield and to the fact that both
the heat radiating and heat conducting losses
50
are limited. The heat radiating losses are limited
since they are substantially con?ned to the ex
posed outer surface of the shield by virtue of the
fact that the inner surface of the shield is sealed
against the ambient atmosphere and to the fur
ther fact that the air con?ned in the pocket I8
is maintained at elevated temperatures by heat
55
which is radiated from the immersed lower por
tion of the shield and from the surrounded por
tion of the rod l5. Also the heat which is lost
by conduction is limited since the temperature
60 gradient between the upper shoulder 2| and that
portion of the rod IS with which it contacts is
slight, and since the heat which is thus lost by
conduction is so limited it ispermitted, in the
reciprocates, and a metal shield carried by the
rod and insulated by con?ned air from that por
tion of the rod which is in line with the level of
the bath when the rod is in its down position,
the length of the shield being such that the 40
upper end thereof remains above the level of the
bath and the lower end thereof remains below
the level of the bath as the rod reciprocates.
3. In a typographical machine, the combina
tion of a pot containing a bath of molten metal,
a reciprocable plunger rod positioned in the pot,
and a metal shield positioned about the rod for
preventing the adherence of molten metal there
to, the upper end of the shield being secured to
the rod above the level of the bath when the 50
rod is in its down position, the lower end of the
shield being secured to the rod below the level
of the bath when the rod is in its up position
and that portion of the shield in line with the
level of the bath when the rod is in its down 55
position being separated from that portion of
the rod about which it is positioned and of such
thinness that its temperature is raised to sub
stantially the temperature of the bath as it is
60
brought into contact therewith.
BENJAMIN F. DAVIDSON.
CLARENCE F. MORSE.
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