AN IMPROVED MANUFACTURE OF ELASTIC COM- POUND APPLICABLE TO THE PRODUCTION OF BRAKE BLOCKS, RAILWAY BUFFERS, BEARING SPRINGS, AND OTHER ARTICLES
Year: 1878

page_text: LETTERS PATENT to James Burbridge, Manager at Messieurs William Warne
and Co.'s India Rubber Works, of Tottenham, in the County of Middlesex,
for the Invention of "AN IMPROVED MANUFACTURE OF ELASTIC COM-
POUND APPLICABLE TO THE PRODUCTION OF BRAKE BLOCKS, RAILWAY
BUFFERS, BEARING SPRINGS, AND OTHER ARTICLES."
·
PROVISIONAL SPECIFICATION left by the said James Burbridge at the
Office of the Commissioners of Patents on the 7th December 1878.
JAMES BURBRIDGE, Manager at Messrs. William Warne and Co.'s India Rubber
Works, of Tottenham, in the County of Middlesex. "AN IMPROVED MANUFACTURE
OF ELASTIC COMPOUND APPLICABLE TO THE PRODUCTION OF BRAKE BLOCKS,
RAILWAY BUFFERS, BEARING SPRINGS, AND OTHER ARTICLES."
The object of this Invention is to obtain an elastic material which is capable of
being moulded or wrought in to any required shape while in a plastic state, and
which will cost much less than india rubber compounds of like elastic quality, and
which will furthermore when cured be free from that clinging quality which is
peculiar to elastic india rubber compounds, and is disadvantageous in some of their
applications.
In preparing my improved compound I take 8 parts by weight of fibrous or textile
cuttings, such as rags, jute, and flax, 6 parts of sulphurized linseed oil, 1 part of
flowers of sulphur, and 15 parts of levigated pumice stone or other suitable granu-
lated substance, and thoroughly incorporate the whole by means of heated pressing
rolls into a perfectly homogenous mass.
I then cut the mass into pieces and force them by hydraulic or screw pressure
into iron moulds corresponding in shape to the blocks or pieces required. While the
material is still in the mould I submit the same to the action of steam heat varying

page_text: from 270° to 300° Fahrenheit, according to requirement, for a period also varying
according to the thickness of the material and quality of elasticity required.
I would remark that the proportions given above will produce the composition
suitable for brake blocks, but these proportions will vary somewhat, according to
the requirements of the case.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Burbridge in the Great Seal Patent Office on the 7th June
1879.
"
JAMES BURBRIDGE, Manager at Messieurs William Warne and Company's India
Rubber Works, Tottenham, in the County of Middlesex. AN IMPROVED MANU-
FACTURE OF ELASTIC COMPOUND APPLICABLE TO THE PRODUCTION OF BRAKE
BLOCKS, RAILWAY BUFFERS, BEARING SPRINGS, AND OTHER ARTICLES."
The object of this Invention is to obtain a tough elastic material suitable for con-
version into brake blocks, buffer heads, bearing springs, and such like articles, and
which is capable of being moulded or wrought into the desired forms while in a
plastic state, such compound costing much less than india rubber compounds of like
elasticity, and when cured being free from the clinging quality peculiar to elastic
india rubber compounds, which quality has been found disadvantageous in some of
their applications.
In preparing my improved elastic compound I use as a basis sulphurizable oil in
place of india rubber, and I proceed in the following manner, keeping as near as
may be to the proportions herein stated, which will form a good compound for
brake blocks I take eight parts by weight of fibrous or textile cuttings, such as
rags, jute, and flax, which have been subjected to the action of grinding rollers, six
parts of sulphurized linseed or equivalent oil, one part of flowers of sulphur, and
fifteen parts of levigated pumice stone or other suitable granulated substance, and
thoroughly incorporate the whole by means of heated kneading rollers into a per-
fectly homogeneous mass.
The dough thus formed I mould under hydraulic or screw pressure into the desired
shape, using for the purpose moulds of cast iron.
While the material is still in the moulds I submit the same to the action of steam
heat varying from two hundred and seventy degrees to three hundred degrees
Fahrenheit, according to the amount of elasticity required in the moulded article.
The duration of this curing process will vary according to the thickness of the
moulded article and to the degree of elasticity it is required to receive. These
variations of temperature and time of exposure to the heat will be regulated
according to the judgment of the workman, whose experience in such matters will
ensure the obtaining of reliable results.
I have stated that the proportions given above will produce a composition suit-
able for brake blocks, but these proportions will vary somewhat, according to the

page_text: requirements of the case; thus, for example, when preparing a composition for
bearing springs I increase the proportion of the sulphurized oil and reduce the pro-
portion of the fibrous material and of the pumice stone in order to increase the
elasticity of the compound. The following proportions will be found to give a good
result, viz., eight parts by weight of sulphurized oil, eight parts of levigated pumice
stone, one part of sulphur, and six parts of ground fibre.
Having now set forth the nature of my Invention of "An Improved Manufacture
of Elastic Compound Applicable to the Production of Brake Blocks, Railway Buffers,
Bearing Springs, and other Articles," and explained the manner of carrying the
same into effect, I wish it to be understood that under the above in part recited
Letters Patent I claim,-
The elastic compound prepared as and for the purposes above set forth.
In witness whereof, I, the said James Burbridge, have hereunto set my hand
and seal, the Fifth day of June, in the year of our Lord One thousand
eight hundred and seventy nine.
JAMES BURBRIDGE. (L.S.)