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Патент USA US2121826

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June 28, 1938.
‘ 2,121,826
Filed Oct. 2, 1935 ‘
Patented June 28, 1938
noon 1m
' Dudley Roberts, New York, N. Y., assignor to Rub
atex Products, Inc., New York, N. Y., a corpora
tion of Delaware
Application October 2, 1935, Serial No. 43,133
ZOIaims. (01. 20-69)
?rst necessary to describe the rubber composition
which I employ in carrying out my invention.
The ingredients entering into the product are
My invention relates to a novel construction of
door jamb and process of making the same and,
more particularly, relates to a novel, cell tight
door jamb and its process of manufacture.
mixed in approximately the following percentages
by weight:
‘ Door jambs, especially those used along the
edges of subway doors, are usually made of .a
rubber composition to provide the desired soft
Per cent
Washed ?rst grade pale crepe or smoked
ness combined with a seallike enclosure. Di?l
culties have been experienced with such rubber
Light calcined magnesia _______________ __
10 because, in obtaining su?icient softness of the
rubber employed, ruggedness against mechanical . Ground gilsnnite
3- 5 10
tear and weather wear are sacri?ced with the Lower melting bituminous substances_____
result that such door jambs have a relatively.
The base ingredient of the product is the rubber
short life.
which is preferably of a pale crepe grade #1,
In a co-pending application Serial No. 717,550, obtained in sheets about 51;" to 1%" x 10" x20".
?led Mar. 27, 1934, of which I am a joint inventor,
These sheets of rubber are passed through
there is described a novel rubber composition (de-v masticating mills consisting of two rollers rotat
tails of which will be given hereinafter) com
ing in opposite directions as in the case of mesh
prising a cellular rubber in which each of the ing gears. One roller, however, rotates slightly
20 minute cells containing gas at a high pressure faster than the other, so that the rubber fed be
are sealed. This sealed cellular rubber is rela
tween the rolls tends to rub on the surfaces of
tively much softer than solid rubber, thus supply
the different speed rolls and a nib is formed as
ing one of the essential properties desired. vIn
asmuch as each cell is sealed from all other cells,
shown at H, Figure 2 of the copending applica
tion, S. N. 717,550, referred to above. ‘The ex
25 it does not absorb water or moisture from the air
tent of this nib depends on the relative speeds
and therefore is not so readily attacked by atmos
pheric conditions. Finally, it may be given con
of the rolls and the nib in turn ‘determines how
much of the two surfaces l2 and I3 of the rubber
engage and are masticated by the respective
siderably greater ruggedness than can be obtained
with solid rubber approaching the softness of this
rolls M and 15.
In employing sealed cellular rubber, however,
the method of 'manufacture does not commer
cially permit the direct molding thereof into the
shape of a door jamb.
Accordingly, an object of my invention is to
provide a novel rubber door jamb and a novel
method of manufacture» of the same.
A further object of my invention is to provide
a novel sealed cell rubber door Jamb and its
degree of mastication depending on the spacing
of the rolls, the temperature and the period of
su?'ron or mineral rubber. This asphalt is di
vided into ?ne particles and passed through'a'
vsixteen mesh sieve. While the rubber revolves
on the masticating rolls, these particles of bitu 45
detailed description which is to follow in connec
tion with the drawing, in which:
4 ‘ ‘Figure 1 is a perspective view of the side of a
. 1081" with sliding door, having secured to its edges
min are shovelled on and are uniformly dis,
tributed over the rubber. The heat of the rubber
melts the bitumen which penetrates into and is
my novel form of door jamb.
Figure 2 is a detail showing one form of my
novel door Jamb.
Figures 3 to 5 are modi?ed forms of the door
‘Figure 6 shows one form of molded material
used to make the door jamb of Figure 2.
_ In order to understand the invention, it is
I have found, however,\that a masti- ‘
cation of one pound per minute at. a roller tem
perature of 150° F. is sumcient for my purposes.
To this resulting soft rubber mass is now added 40
an asphalt product or soft bitumin, such as
40 method of manufacture.
There are other objects of my invention which
" together with the foregoing will appear in the
The rolls are steam heated to a temperature of
approximately 150° F. as the rubber sheets are
fed between them. The rubber is masticated or
softened in this process, the individual sheets
combining into a single mass of soft rubber, the
80 rubber.
absorbed by the rubber.
The bitumin acts as a ?ux at low temperatures 50
in the stage of‘partial vulcanization to be‘ ex
plained hereinafter. Any other low temperature
?ux may be substituted, 1. e., a low melting hy
drocarbon of the asphaltic group of a bituminous
or waxy nature, having ?uxing properties,‘ such
- ‘as para?in wax and steario- acid. '?urlng
nd. two‘
il'l‘heldistjorting effect‘ of
‘corrected byiPrQVidi-ng ‘a-sécond twenty-four hour
' ' Perm-1112's 'darki’rjwarm. 'dry roomq-atabout
fthei's me ttem ature as the previous rest period.
'passingrthel-rubber.throughgthe rolls is now again
- stage the rubber has turned'froma light to ajdark
‘Ground gilsonite,
_‘ into _. even‘?ner par
vticles than bitumin and passed through a- one-Q
‘Again'the length ofltl‘ie' rest period inay vary, but
hundred and sixty mesh ‘sieve, is new sprinkledv
‘ or 'shovelled on the rubber, jstill‘p'as‘sing through . .at least twent
‘the masticating rolls.
" _\hours is ‘necessary and the
more nearly "the ; rubber is “
Gils'oni'te is'anas'phalt like . '
bitumin,. but has a much‘ higher‘ melting point; .1
It willv accordingly'not be'melted by the rubble
but will nevertheless penetrate into,’ impregnate".
of‘ tyvdIrOI-leIs zrotatiniat' the" same speed.‘
and be absorbed ‘by'the soft spongy massof --rub Therubber. is'Yfed-"betwcen the rolls maintained at
ber." »Gilsonite'functions.asa?ux ina‘high'tem " ‘a temperaturej‘o'f -i"§'14_0° F; This ‘is
perature' stage to.v be described , hereinafter, and r‘ continued-until , the ‘ .'rubbe'r.--'again . becomes soft
‘ may accordingly be replaced by'any ,suitable‘highf and forms lama; uniform, plasticwcomposite mass 15
temperature flux such as'a-higlr temperature. -' and ‘during-whichithe rubber may-be formed into
asphalt. In ‘using jthelexpress‘ion -“fiux”,-- it, ‘will. vslabs,
board ‘,,,_ tea-"after which 'aifurther rest
periodiof'twelve hoursisprovided. '0r,_if desired,
be understood‘ that‘ I mean Iasubstance acting
. to ,amalgamateor assist inthe. vulcaniz1ng.1~
: “ thé'rlflbbef may'i
20 ‘ Summarizing the above, three stages have been' chine which; p’
passed through 1 a. {forcing ma-'
ferf tduse‘. for‘ pre-forming ‘the
rubberTinv.-l any" desired" shape,'_'- _such as aeroplane
described. ‘In the first,‘ the rolls were heated't'o a
temperature of 150° F. while’ma'sticating or-sofe , wings," struts, 1pont‘oons'; etc‘.
y-If .preferred, the
tening'the rubber to combine the individual sheets f forcing operations f ay 'als'ofnbeused to soften the
into ajsingle soft spongy mass. Assuming ‘twenty , rubber in the ea’ c ' Her‘, stages described here
25 four pounds of rubber, twenty-four minutes may .
gesiofjgtreatment described
applied to the rubber as it continues to pass over
ta quantity of air has been
such an extent;
' in. agitating the rubber to
absorbed ‘by_.th___-, rubber. The presence of-this
the rolls, inthc proportions given above, and this,i
ordinarily be required for this operation.
The various
In the second stage, a low'temperature ?ux, is’ ‘ above have‘ .resu
air may have
'riousji deteriorating
effect during
by reason of the heat, melts into and is absorbed ‘ ‘
' the subsequentfstages to'bev described hereinafter.
third stage, a high temperature
?ux is This may be described as'followsz‘
admixed with the rubber while it passes through ' VLikeglass, rubberis a plastic or super-cooled
viscous‘liquid. Normally, 'itwould be crystalline,
The second and third stages take fourteen mine __ but ispreVented‘fmm becoming. so because. of vthe
utes additional to the twenty-four minutes for complexity of-the'molecules which are large ‘and
mastication and result in a rubberimpregnatedj slow-moving due‘ to. the viscosity of the mixture.
with a‘high‘ and low temperature hydrocarbon; This’ superecooled" viscous liquid ‘is chemically an
The molecular structure of rubber is theoretically ‘unstable ‘product. which'tends to stabilize itself.
described as normally being, in the ‘form-10f a‘ ' This is p'articularly'itrue if the rubber is' warmed
the rolls, again in the proportions giv'en‘above.
spiral. This may be thought as giving to theirubé
tojust below melting point which favors crystal‘
ber its‘ elasticity and strength. During the work
‘ 'lization." The presence ofair under these condi- '
tions ‘is; particularly‘ conducive to: crystallization,
ing of the rubber described above, a disturbance
; a, simple; oxidation resulting from. ‘a; "relatively
I of the molecular structure apparently occurs:
to lose its natural» qualitiesi'
.45 the rubber tends
I‘ simple'rubbercompound which:crystallizesiout.
It is essential to providea restv period for ‘the;
, Moreover,rubber-oxidizeseasily
because" it has
bondsf‘which tend to read
at ‘this
to restore
stage ofitself
‘the to
tov permit
condis. 1-,unsaturationsordoubIe
ilycombine' witlr'jthe ‘oxygeirfespecially under the
; _ influenced‘ heat and ‘ pressure, thus‘ making the
Accordingly, in the next or fourth-"stage, their }_,rubberf_.brittle.‘ YInu'the ‘presence of air,_ rubber 50
vrubber, now ?at, soft and porous, is permittedtb ‘thereforetendsxtoxoxidize. Attacked or oxidized
byI'even. gsmall amount-Ofi§1f:a.the rubber becomes
cool off and is left‘to rest for. about i'iwe'lve-hours;-v
I preferably in a‘ dark; dry room at a temperature
. period,
ofv fromthe80°more
to 100°
the rubberregains'
F. The; longer
Cl 91
condition, but I havev found thatitwelve hcurs'l-f"
will ordinarily be suii‘lcient to'resto'reit to about i
its original condition.
re 'ént this,‘ the;rubher;f-asiis~<>omm°nly
{sci that'it no
‘geniinyth'e air.
Following this rest period, these-‘slabs of rubber T Q
complex com
are placed on rolls maintained at temperatures; .1
s >
I of from 120° to 130? F. As the rubber ‘passages,
1' ‘tween the rolls, additional'slabs are ‘added, which
ultimately ‘combine into“ asoft mass
of rubber.
Of-BJI‘: may resuitin intoxication. ,f r'fthe‘lreasons'
-‘ ._ When the mass has been formed with adjacent ..
Texpl'alned abovaieven before vulcanization sets in.
. The
iengaging surfaces adhering, sulphurvjand light; ' rliccording'ly, itgis'
tanmororce out all
calcined magnesia, in, the ‘proportions given .the air thatrn‘iayfj.have'?‘niixed with» the‘ rubber
above, are added as thelrollsrcbtat'e.v
the vulcanizer and the light calcined-.m’agnesia '
ulcanization, to be
is the rubber toughener." Any equivalentrubber;v gfTolthislend'. the rubber. is; passed between suc
toughener, such as zinc..oxide; m'ay‘replace» the) 3., " essive enenders _ ' maintained at _ a -' temperature 70
calcined magnesia. For
for athorough
period ofabsorptiomthe
abouttw'enty io'fg'fr m;-130,"."t'_o 1,50_°-F.'f jThe’calender ,mill com
prises-aseriesof rolls decreasingly spaced from
‘ rolling is continued
. .
.. V_ a , _Z each-other insuceessivesteps.
In the ?rst step,
{as shownigin gFigure'l-‘l'v' of the application S. N.
. strips or slabs of about one-half inch in thickness 1 717,550, referred ‘to: above, the rolls are relatively 75
- Theproduct is now removed from 'the'rolls in;
result that the pressure is removed and the
ifar apart, in thenext stage, closer, etc. The‘ the
gas in the cells immediately expands .the rubber
‘rubber passing through the calenders forces all
' ‘the trapped air out and is reduced in size.’ After
the rubber passes the last rolls, a sheet of cloth
is applied thereto to close faults appearing in
the rubber ,and to prevent the rubber from con
tracting.- The cloth, having a limited expansion,
keeps the stretch in rubber and maintains it a
predetermined thickness.
The rubber is now cooled to room temperature
and the cloth removed, leaving a sheet ofun
treated rubber. The product is now ready vfor
the two ?nal stages of vulcanization to' be de-'
scribed. , These vary somewhat for different prod
15 ucts. Approximately ten such sheets of rubber
may-be placed with metal sheets interposed be
tween each sheet of rubber, and the whole'placed'
in a metal container having an internal dimen
sion slightly larger than the combined sheets.
20 A cover is then fastened into place on the con
tainer. A number of these containers are then
placed into a gassing autoclave which is then
closed and fastened down. The autoclave has
previously been aired by passing steam through
25 the container and heating it to a temperature of
from 180° to 212° F. to remove moisture.
A vacuum pump is then connected to an inlet
of the container to extract the air until a vacuum
of about ?ve inches is obtained. The evacuation
30 is important for the reasons already pointed out
about four times.
v This partially cured rubber is now placed in
a mold suitably constructed to form the shape i
shown in Figure 6.v -
As shown in Figure 6, the mold is of a shape
to produce rubber symmetrical in shape. com
prising two end' portions 2|) and a central o?set
portion ll forming shoulders I‘ and IS with one
of the edges of each end portion 20 and shoulders
I2 and H with each of the opposite edges of .
portion 20.
The partially vulcanized rubber placed in the
mold for producing this special shape of rubber 15
isnow subjected to the ?nal vulcanization. Each
mold is placed in a mold of the desired dimen
sions. Each mold is placed between platens and
saturated steam is applied at ninety-?ve pounds
for about forty to forty-?ve minutes. This is
the ?nal stage of the process of the curing and
expansion. The rubber expands to the size of
the molds and at the same time complete .curing
or vulcanization of the rubber is obtained. The
steam is now turned off and the product per 25
mitted to cool. If desired, cooling, may be
hastened by applying cold water. The end prod-.
not is an expanded cellular inert gas ?lled prod
uct weighing about ?ve pounds per cubic foot.
This stage, during which the vulcanization is 30
hereinbefore. 'When the container has been .. completed, must take place within forty-eight
‘evacuated, gas is admitted into the autoclave at hours after the completion of the partial ex
a pressure of from 150 to 200 atmospheres. Any pansion and vulcanization. Otherwise su?lcient
gas may escape from the partially vulcanized
inert gas, preferably non-combustible, and hav
ing no a?inity for raw rubber, such as nitrogen rubber so that there is a material loss in volume. 35
(N), ammonia (NI-I3) , helium (He) may be used
for this. Thus air would be disastrous, if used.
Forcing air into raw rubber at several hundred
atmospheres pressure ‘and at or'near vulcanizing
temperatures, would tend to oxidize the rubber
very rapidly and before vulcanization set in, re
sulting in an undesirable product. Moreover, it
would be dangerous practice, because a spark
would cause a terri?c explosion.
While the gas is being forced into the rubber,
steam at eight pounds pressure is admitted to
the steam chest. About thirty minutes are neces
sary for the container to reach a stable tempera
ture, and thereafter the container is maintained
50 at the same temperature continuing to supply
steam at about eight pounds pressure.
The conditions in this stage are critical and
accordingly both the pressure of the gas and the
temperature of the container must be correct.
‘ In the event that more than forty-eight hours
elapse before the last stage of the process occurs,
it is preferable to regrind the material and add
it into the new dough in small percentages.
It is also possible, alternatively, in the event 40
that more than forty-eight hours is to elapse, to
take care of this condition by carrying on the
?rst stage to a further degree of vulcanization
than originally contemplated by applying the
steam for a longer period of time or at a higher 45
temperature than isobtained by eight pounds of
In fact, I have found from experiments that
the ?rst stage can be carried on at from eight to
sixteen pounds of steam, although better results 50
are. obtained at the lower range. When the
greater degree-of vulcanization occurs, the ma
terial can be kept for a longer period than forty
eight hours without the gas diffusion.
The ?nal product, depending upon the per; 55
centages of the various ingredients used is a soft
light rubber of multitudinous minute sealed cells,
jacket produce a'temperature at which partial' each cell apparently containing gas at a high_
vulcanization proceeds to a substantially uniform pressure.
The rubber in the form of Figure 6 is bent 60
degree throughout the body of the rubber. This
partial vulcanization functions to harden the about an imaginary center of the portions it
rubber su?lciently so that it retains the gas forced until the faces or edges of portions 20 are in
into the rubber. At this time substantially little contact with each other. ‘Strips of fabric l8 and ‘
l9 (Figure 2) of relatively stiff composition are
or no expansion of the rubber has taken place
vulcanized to the rubber along the upper edges 65
The autoclave is now permitted to cool o? of portions 20, ?tting against the shoulders I!
under atmospheric conditions and subsequently and I3 and having protruding end portions 3|.
cold water is forced through the steam jacket These protruding portions may now be secured
until a temperature of 60°-70° F. is reached. to the edge of a door 23 (Figure 2) _ or 24 (Figure
1) by any suitable means as rivets 22. The rub 70
70 This permits the rubber now in semi-cured state
when thus secured forms a hollow space H.
to set.
The advantages of this construction will now
Excess gas in the autoclave is now removed.
55 The rubber, while exposed to the gas, is in a soft
plastic state and therefore readily receives the
gas. The eight pounds of steam in. the steam
The rubber being partially cured, will hold gas
under pressure in its individual cells. The rubber
75 sheets are now removed from the containers with
be obvious. Not only does this celltight rubber
have a greater resistance to weathering and
greater resistance to mechanical inJury, but be 75
cause of the minute sealed cells, it provides a
greater cushioning effect than is attainable with
ordinary rubber.
Moreover, by the special mold,
a single inexpensive piece is formed with a hollow
space to further increase the cushioning e?ect.
cation of Roberts et al., 21,380, ?led May 14, 1935.
I do not intend to be limited by the specific
formulae, process or mold construction here illus
trated, but intend rather to cover door jambs -.
constructed of a sealed cellular rubber in inex
In Figures 3 to 5, I have illustrated several of
pensive single molds. - It will be obvious that the
the many modi?cations my invention may under
go. Thus, I may,‘ if preferred, vuicanize the
usual electrical contactors are placed in the space
- fabric 26 to the bottom edge of the rubber after
10 the two faces of sections 20 have been brought
into opposed relation.
Or I may obtain any de
H and operated when the rubber'is compressed
by the closing of the sliding door 24 of car 25.
I claim:
1. A door lamb comprising fabric ‘securing
means, soft closed cell gas expanded rubber posi
sired arrangement or shape or number of spaces
such as arch 21 and oval 28 in Figure 4 or the two‘ , tioned in adhesive contact with said fabric secur
shown at 29 and 30 in Figure 5. These shapes ing means. the soft closed cell gas expanded rub
15 and their arrangements depend merely on the ber constituting the working face of- the door 15
shape of the mold.
Moreover, although I have described for pur
poses of illustration, one process and formula for
manufacturing the sealed cellular rubber, it will
20 be understood that I may vary this in the light
of the present acquired knowledge for manufac
turing this rubber. Thus, I may use the formula
and process described in the application of Peel
et 9.1., 26,164, ?led June 12, 1935, or of the appli
2. A door jamb comprising fabric securing
means, soft closed cell gas expanded rubber posi
tioned in adhesive contact with said fabric secur
ing means, the fabric securing means. extending 20
along only a portion of the contacting surface of
the closed cell gas expanded rubber.
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