Improvements relating to the Treatment of Plastic Rubber Compounds.
Year: 1895

page_text: [Communicated from abroad by WHEELER CABLE, of No. 28 Essex Street,
Boston, in the County of Suffolk and State of Massachusetts, United States.
of America, Rübber Manufacturer.]
Improvements relating to the Treatment of Plastic Rubber
Compounds.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby
declare the nature of this invention to be as follows:-
My invention is an improvement in the art of treating plastic rubber compounds,
and especially those wherein the rubber is largely or entirely such as is known as
reclaimed," that is old rubber worked over.
66
249-155
it
Vast quantities of this stock are annually used, and for many purposes.
is scarcely inferior in serviceability to fresh gum, while its cost is but a small
fraction of that of new rubber. Great care in treating it is, however, necessary,
especially where it is to be subsequently spread thin to serve as a coating for woven
or other fabrics, which are to be thereby rendered water-proof.
calender,
For this purpose it has long been common to treat the compound in a
between the upper and middle rolls of which it passes in a very thin sheet, so that
the workman, scanning this sheet with quick, practiced eye, may remove, while it is
passing downwardly on the middle roller any considerable particles of foreign matter,
the presence of which in the compound would cause imperfections in the coating
when subsequently spread.
To remove these impurities it is absolutely essential that the plastic sheet shall
be so thin that they are visible in it and may be picked out as the material passes.
For practical success this should be done, without stopping the machine unnecessarily.
Here a difficulty hitherto insurmountable has arisen. The middle calender roll soon
becomes materially heated, and the plastic sheet, having a thickness not much
exceeding the hundredth part of an inch, clings to the roller surface, tending to
follow it upwardly and again pass between the upper and middle rollers, thus
clogging the machine or making it inoperative until stopped, and the roller cooled.
This is because there is not sufficient tenacity in the thin sheet of this reclaimed
rubber to pull it away from the roller; but if the sleet passes before the
workman's eye with sufficient thickness to insure its removal freely from the
roller he cannot see most of the impurities, and bence the stock will be of inferior
quality and the coating subsequently applied to the fabric will be full of minute
holes.
My improved method solves this difficulty in a very simple manner, yet one that
has hitherto eluded the thoughts of skilled workmen notwithstanding the urgent
need of relief for many years.
i
Instead of thickening the sheet where it passes for inspection before the
workman's eyes, or attempting to remove it while so very thin, I double its
thickness automatically after it has been inspected. To do this practically and
conveniently I gear the lower roller to run at about half the surface speed of the
middle one, with which it is in close proximity, thereby causing the sheet to be

page_text: transferred from the roller on which it was inspected to the surface of the lower
roller and to be simultaneously about doubled' in thickness owing to such reduction
in speed and to the increased distance between the lower rollers. This increase in
thickness gives to the sheet sufficient body and cohesiveness to insure its ready
separation from the roller surface.
For this purpose I provide a small delivery roller in the rear of the lower
calender roller, and belted to it or otherwise driven at somewhat higher speed
so as to pull the sheet away from the calender. From this small roller the
rubber sheet, inspected on the middle calender roller. and subsequently thickened,
is delivered continuously without the slightest recurrence of the former difficulty.
In constructing an apparatus according to this invention I provide three cylindrical
steel rollers, mounted in the usual bearings in the upright standard of the frame, the
middle roller being in fixed bearings and the upper and lower rollers capable of
accurate adjustment toward and from it.
The plastic mass of rubber under treatment is arranged in the. bight of the
upper and middle rollers, which are geared to turn with equal speed or the middle
roller at a higher speed than the upper roller. They are for my purpose, set
very closely together, leaving only space for a sheet about the hundredth part
of an inch in thickness spread uniformly over a portion of the surface of the
roller and passing slowly downwardly before the watchful eyes of the workman,
who is thus enabled to detect any considerable impurities therein, and remove
them by a quick movement of the hand, leaving a ragged hole in the thin sheet of
stock. This hole is of no possible consequence, since the only object is to free
the stock from foreign matter, the rubber being again massed and subsequently
treated in other machines for surfacing fabrics to be water-proofed and for other
purposes.
The middle and lower rollers are set about twice as far apart as the upper.
and middle rollers, and are geared together, the gear wheel on the lower roller
having about twice as many teeth as that on the middle roller so that the one shall
revolve with about half the surface speed of the other. This 'difference in speed
causes the rubber sheet to part from the middle roller and move downwardly on the
opposite side of the slower roller. Simultaneously with and in consequence of this.
change of speed the soft rubber sheet substantially doubles in thickness, the two
rollers being far enough asunder to insure this.
At the back of the lower roller I mount the small delivery roller in suitable
bearings, and I cause it to revolve at a surface speed sufficiently faster than the
lower roller to overcome the stretch of the sheet, and to pull it free. This I do by
belting it to said roller or by an interposed friction wheel of proper diameter.
This simple attachment pulls the thickened sheet continuously from the roller and
deposits it on the platform, or otherwise, in folds or layers forming a plastic mass for
subsequent treatment, the impurities having been detected and picked out while the
compound was rolled down thin, and the desired tenacity in the sheet enabling it to
be removed alone, accompanying its thickening.
Under my improvement, with less manual labour than has heretofore been
required, I can turn out daily, without any trouble, twice as much of the finished
product. as was practicable under the old system, with its waste of time and constant
annoyance. The value of this improvement, as applied simply to the treatment of
the millions of pounds of old rubber annually reclaimed, will be apparent.
Dated th: 001 1
T
1000

page_text: Improvements relating to the Treatment of Plastic Rubber
Compounds.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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:-
My invention is an improvement in the art of treating plastic rubber compounds,
and especially those wherein the rubber is largely or entirely such as is known as
reclaimed," that is old rubber worked over.
Vast quantities of this stock are annually used, and for many purposes it is
scarcely inferior in serviceability to fresh gum, while its cost is but a small fraction
of that of new rubber. Great care in treating it is, however, necessary, especially
where it is to be subsequently spread thin to serve as a coating for woven or other
fabrics, which are to be thereby rendered water-proof. For this purpose it has
long been common to treat the compound in a calender, between the upper and middle
rolls of which it passes in a very thin sheet, so that the workman, scanning this
sheet with quick, practiced eye, may remove, while it is passing downwardly on
the middle roller any considerable particles of foreign matter, the presence of
which in the compound would cause imperfections in the coating when subsequently
spread.
To remove these impurities it is absolutely essential that the plastic sheet shall
be so thin that they are visible in it and may be picked out as the material
passes. For practical success this should be done, without stopping the machine
unnecessarily. Here a difficulty hitherto insurmountable has arisen. The middle
calender roll soon becomes materially heated, and the plastic sheet, having a
thickness not much exceeding the hundredth part of an inch, clings to the roller
surface, tending to follow it upwardly and again pass between the upper and
middle rollers, thus clogging the machine or making it inoperative until stopped,
and the roller cooled. This is because there is not sufficient tenacity in the thin
sheet of this reclaimed rubber to pull it away from the roller; but if the sheet
passes before the workman's eye with sufficient thickness to insure its removal
freely from the roller he cannot see most of the impurities, and hence the stock
will be of inferior quality and the coating subsequently applied to the fabric will
be full of minute holes.
My improved method solves this difficulty in a very simple manner, yet one that
has hitherto eluded the thoughts of skilled workmen notwithstanding the urgent
need of relief for many years.
Instead of thickening the sheet where it passes for inspection before the
workman's eyes, or attempting to remove it while so very thin, I double its
thickness automatically, after it has been inspected. To do this practically and
conveniently gear the lower roller to run at about half the surface speed of the
middle one, with which it is in close proximity, thereby causing the sheet to he
transferred from the roller on which it was inspected to the surface of the lower
roller and to be simultaneously about doubled in thickness owing to such reduction
in speed and to the increased distance between the lower rollers. This increase in
thickness gives to the sheet sufficient body and cohesiveness to insure its ready
separation from the roller surface.
For this purpose I provide a small delivery roller in the rear of the lower
calender roller, and belted to it or otherwise driven at somewhat higher speed so as

page_text: to pull the sheet away from the calender. From this small roller the rubber.
sheet, inspected on the middle calender roller and subsequently thickened, is
delivered continuously without the slightest recurrence of the former difficulty.
The accompanying drawing shows a transverse vertical section through a
calender, furnished with my supplementary roller, and adapted to the practice of
my improved method.
In constructing an apparatus according to this invention I provide three
cylindrical steel rollers A, B, C mounted in the usual bearings in the upright
standard D of the frame, the middle roller B being in fixed bearings and the
rollers A and C capable of accurate adjustment toward and from it.
The plastic mass of rubber R under treatment is shown in the bight of the
rollers A, B which are geared to turn with equal speed or the middle roller at a
higher speed than the upper roller A. They are for my purpose, set very closely
together, leaving only space for a sheet S about the hundredth part of an inch in
thickness spread uniformly over a portion of the surface of the roller B and
passing slowly downwardly before the watchful eyes of the workman, who is thus
enabled to detect any considerable impurities therein, and remove them by a quick
movement of the hand, leaving a ragged hole in the thin sheet of stock. This hole
is of no possible consequence since, the only object is to free the stock from foreign
matter, the rubber being again massed and subsequently treated in other machines
for surfacing fabrics to be water-proofed and for other purposes.
The rollers B and C are set about twice as far apart as the rollers A and B, and
are geared together, the gear wheel on the lower roller having about twice as many
teeth as that on the middle roller so that the one shall revolve with about half the
surface speed of the other. This difference in speed causes the rubber sheet S² to
part from the middle roller and move downwardly on the opposite side of the slower
roller C. Simultaneously with and in consequence of this change of speed the soft
rubber sheet substantially doubles in thickness, the two rollers being far enough
asunder to insure this.
At the back of the lower roller C I mount the small delivery roller E in suitable
bearings, and I cause it to revolve at a surface speed sufficiently faster than the
roller C to overcome the stretch of the sheet, and to pull it free. This I do by
belting it to said roller C or by an interposed friction wheel F of proper diameter.
This simple attachment pulls the thickened sheet S2 continuously from the
roller C and deposits it on the platform, or otherwise, in folds or layers forming a
plastic mass for subsequent treatment, the impurities having been detected and
picked out while the compound was rolled down thin, and the desired tenacity in
the sheet enabling it to be removed alone, accompanying its thickening.
Under my improvement, with less manual labour than has heretofore been
required, I can turn out daily, without any trouble, twice as much of the finished
product as was practicable under the old system, with its waste of time and
constant annoyance. The value of this improvement, as applied simply to the
treatment of the millions of pounds of old rubber annually reclaimed, will be
apparent.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
1. The improvement in the art of treating plastic rubber compounds, which
consists in spreading such material in a very thin sheet upon a moving surface,
inspecting and removing impurities therefrom while so spread and moving, and then
thickening said sheet at its forward end and removing the thickened sheet from its
carrying surface, substantially as and for the purpose set forth.
2. The improvement in the art of treating reclaimed rubber compounds, consisting
in spreading such material in a very thin sheet, inspecting and removing impurities
therefrom while so spread and moving forward, then transferring such material to
a surface moving at a reduced speed, and simultaneously increasing the thickness

page_text: of the sheet in a corresponding ratio, and subsequently removing the thickened
sheet from said surface and depositing it in a mass, substantially as set forth.
3. The combination of the calender rollers A. B, geared for moderate surface
speed, with the lower calender roller C geared to run at about half said speed, and
with the supplementary delivery roller E driven at somewhat higher speed and
adapted to pull the thickened sheet of compound alone from such slow roller,.
substantially as and for the purpose set forth.
Dated this 28th day of October 1895.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.