Improvements in Compound Sheet Metal Plates, and in the Process of Producing same.
Year: 1892

page_text: Date of Application, 20th Dec., 1892-Accepted, 25th Feb., 1893
COMPLETE SPECIFICATION.
Improvements in Compound Sheet Metal Plates, and in the Process
of Producing same.
We, WILLIAM BARNUM HOLLINGSHEAD of Bronxville in the Town of East
Chester, in the County of Westchester State of New York, Electro-Metallurgist,
and SYDNEY HOWARD CARNEY of No. 201 West 55th Street in the City, County
and State of New York, United States of America, Physician, 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:-
Our invention relates to the production of compound sheet metal plates composed
of a rolled iron steel or other oxidisable base having its surfaces coated with
protective metals or alloys, as copper, zinc, tin and the like but more particularly
copper, and it consists in the improved mode of applying such protecting surfaces
whereby better and more effective and lasting adhesion of the protective metal is
secured, and in the improved article of manufacture comprising such compound
plates having the improved surface protecting coatings of our invention, as
hereinafter fully described reference being made to the accompanying drawings in
which :-
Fig. 1, is a side elevation of a pair of rolls and section of a part of a plate between
them as in the process of treatment for producing surfaces of the protective coatings
deposited thereon in crystalized form as in the electro-plating bath.
Fig. 2, is a similar view illustrating the repetition of the rolling process after
another deposition of a second or third increment of the coating which is necessary
to insure the production of the impervious coating without condensing the coating
material so deeply by rolling as to disturb the adhesion of the crystals with the
surfaces of the plates.
Fig. 3, represents a part as in Fig. 1, enlarged for greater clearness.
We are aware that it has been attempted to force deposited copper into closer
contact with iron in the manufacture of printing rolls by subjecting the deposited
coating of copper to considerable pressure by the action of a burnishing roll of
hardened steel as set forth in the Specification to Letters Patent of the United
States to Wilde No. 193,204, but our experience in the art has demonstrated that
any such pressure as effects the deposited crystaline coating to the depth reaching
the surface on which the same is deposited has the contrary effect of largely
diminishing the adhesion between the two metals and if continued to a certain degree
effects complete separating as we have abundantly demonstrated by the use of this
very means in the manufacture of copper tubes by depositing the copper on a
mandrel and then subjecting the coated mandrel to pressure between rolls sufficient
to compress the copper between them and the surface of the mandrel which, besides
condensing the copper to the proper consistency, also draws it on and separates it
from the surface of the mandrel so that the copper is free to be drawn off from the
mandrel in the form and condition of a seamless tube.
In our present invention we apply the coating a, of ductile metal on the surface
of the plate b, by the electro-plating process and then proceed to roll, hammer or
otherwise reduce the exterior portions of the coatings to smooth surfaces, as nearly
as possible impervious to moisture, without disturbing the inner portions of said
coatings adhering to the surfaces of the base plate b, which we do by carefully
gauging the rolls d, or other means of effecting the reduction of the projecting
points of the crystals so as to spread and meet together in a continuous uniform
surface over the lower or inner portions which are left undisturbed and therefore
unaffected as to their power of adhesion to the base plate.

page_text: We then deposit another increment of the coating material on the previously
deposited and rolled coating and subject it to another rolling process as in Fig. 2,
the rolls being likewise gauged to prevent disturbance of the contact of the crystals
of the previously deposited coating with the plate and thus secure plates fully
protected for practical use for roofing and other like uses.
The crystals will be finer or coarser according to varying conditions of the kinds
and qualities of coating material used, and of the baths in which the application is
effected, where several layers are applied they may be graduated in finer crystals
and smaller quantities successively.
We are aware that in the Specification to Crooke's United States Patent
No. 98,354 a process is described of producing ordinary plated surfaces upon rough
metals by dipping them in a bath of tin, passing the plates between polished rolls
to give an even surface, then manufacturing the desired articles from the tinned
plates, then burnishing the parts made rough in the manufacturing process, and then
electroplating the finished articles to produce an ordinary plated external surface
which may be burnished or not, and wo make no claim for such process the product
of which though suited for the purposes set forth in the said Specification which
contemplates articles for use in places protected from outdoor exposure, would
be of little use for our purpose, which is more particularly to provide roofing
plates.
It is well known that tinned plates are not lasting for such use except when
carefully protected with paint.
It is not feasible to increase the protective quality of tinned coatings by successive
dippings of the plates in the bath of molten metal, because the previously deposited
coating melts to such extent when again immersed that the quantity adhering
remains about the same.
An electro deposited coating on a tinned surface as in Crooke's process would not
be adapted for our purpose because the soft surface holding the deposited crystals
would yield under such pressure of the rolls as is necessary in our process to close
the cells of the exterior portion of the crystaline coating and would thus defeat the
purpose of the rolling.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that
what we claim is :-
1. The process of coating or plating oxidizable sheet metal plates with ductile
protective metals or alloys which consists in applying a layer of the coating material
adhesively on the surfaces of the plates in crystaline form by electro-deposition and
producing surfaces of the coating material impervious to atmospheric effect by
rolling, hammering or planishing the said layer to a limited extent, and thus
condensing smoothing and uniting an exterior portion of less thickness than the
depth of the deposited material and without disturbance of the portions of the
crystals in adhering contact with the plates substantially as described.
2. The process of coating or plating oxidizable sheet metal plates with ductile
protective metals or alloys which consists in applying a layer of the coating material
adhesively on the surfaces of the plates in crystaline form by electro-deposition and
producing surfaces of the coating material impervious to atmospheric effect, by
rolling, hammering or planishing the said layer to a limited extent, and thus
condensing, smoothing and uniting an exterior portion of less thickness than the
depth of the deposited material and without disturbance of the portions of the
crystals in adhering contact with the plates, then depositing a second layer of
the said material in like manner and again rolling, hammering or planishing the
same also to a limited extent for the protection of the said crystals adhering to the
plates, these two layers so applied constituting a homogeneous skin of the protected
material, the inner portion adhering to the plates being in the natural crystaline
condition of deposition substantially as described.
3. The improved article of manufacture consisting of an oxidizable metal plate

page_text: coated with protective metals or alloys having wrought surfaces impervious to
atmospheric effects, and also having the natural or undisturbed crystaline inner
form as deposited on and adhering to the surfaces of the metal plate substantially
as described.
Dated, New York City, November 22nd 1892.
WILLIAM BARNUM HOLLINGSHEAD.
SYDNEY HOWARD CARNEY.