The Manufacture and Production of Compositions of Matter suitable for use for Bearings, Packings, Projectile Guides or Rings, Electric Conductors, and analogous articles.
Year: 1892

page_text: Date of Application, 6th Sept., 1892-Accepted, 15th Oct., 1892
COMPLETE SPECIFICATION.
The Manufacture and Production of Compositions of Matter suitable
for use for Bearings, Packings, Projectile Guides or Rings,
Electric Conductors, and analogous articles.
1, PHILIP HENRY HOLMES of Gardiner in the County of Kennebec, State of
Maine United States of America, Mechanical Engineer 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 consists of a composition of matter of which plumbago is the
base, the composition being applicable for use as a bearing, packing, projectile
guide or ring and in any place where two parts come into frictional contact, and it
can also be used as a conductor of electricity, and in other cases where plumbago
is required in a solidified or moulded form.
The object of my said invention is to produce a composition that will be as free
as possible from substances other than carbon.
The said composition consists of plumbago, carbonizable fibre, and carbonizable
liquid moulded, dried and heated to such an extent as to carbonize the fibre and
liquid.
I carry out my invention in substantially the following manner :—
I first take plumbago, (by preference in a finely divided state) and I float it so
as to obtain it in as pure a condition as possible, although for some purposes a
commoner grade of plumbago may be used, the necessary condition being in.
accordance with the purpose for which the article to be produced is intended. I
then mix the plumbago with carbonizable fibre, such for instance as wood fibre in a
pulpy condition, the object of reducing the wood fibre to a pulp being to separate
the fibre so that it will become finely divided and intimately mixed with the plumbago. i
The pulp and plumbago are mixed in a liquid preferably water, so as to form a
pasty mass, and to this mixture is added a quantity of finely divided granular
mineral substance which serves, with the fibre, as a filtering medium when the
mass is compressed in the mould to expel the water or other liquid. The
granular mineral substance which I prefer to use is one of an inert character such
as gypsum for example which I have found to answer well although it will be
understood that other granular mineral substances will accomplish the purpose.
The proportion of plumbago to fibre will vary considerably.
For some.
purposes the proportion of plumbago will greatly exceed the fibre, whilst in
other cases the proportion of plumbago and fibre may be equal, or nearly equal.
The inert granular mineral substance is added to act as a filtering medium, and
may vary according to the character and form of the mould.
The mixture is introduced into a mould having perforations to allow for the
escape of the water or other liquid employed and provided with a plunger for
compressing the mixture in the mould. I preferably pump the mixture into the
mould after which the plunger is forced in until the mixture is compressed to the
degree required and the water or other liquid is driven off from the mixture
through the perforations in the mould.
The compressed mixture is then removed from the mould and dried so as to .
expel all of the moisture therefrom, and is then immersed in a bath of a suitable.
carbonizable liquid, such as oil for instance and is allowed to remain therein until
it is impregnated or saturated with the said carbonizable liquid and to facilitate this >
impregnation it is preferable that the bath of carbonizable liquid should be hot,
the mass being more or less saturated with the carbonizable liquid according to the
character of the composition. Any oil or varnish which can be carbonized will
answer the purpose.
It is preferable to place the article so treated in a closed vessel heated to a

page_text: sufficient temperature to assist in driving the carbonizable liquid into the interstices
of the composition.
The mass after being thus treated is then placed in a suitable retort or oven in
order to subject the compound to the process of carbonization, preferably out of
free contact with air. The mass is thereby changed into a tough coherent mass
containing an excess of plumbago which is caused to cohere by the double action of
the fibrous or structural carbon derived from the carbonization of the carbonizable
fibre and the deposited carbon derived from the carbonization of the oil or other
suitable carbonizable liquid which was incorporated with the mixture prior to
carbonization and which acts as a binder for the mass.
The extent of carbonization of the mass will depend greatly upon the purpose
for which it is to be used as in some cases it may be preferable to carbonize only a
portion of the mass while in other cases it will be preferable to carbonise the
entire mass.
The composition thus produced makes an excellent bearing, but is also a good
conductor of electricity as the carbonizable liquid and fibre have been converted
into electric conducting carbon.
In some instances it may be desirable to merely carbonize the fibre, and in this
case the heat is carried to such an extent as to carbonize the fibre but not to
carbonize the main body of carbonizable liquid.
The compound after being treated to carbonize the fibre and liquid may be
saturated or impregnated with a drying oil or its equivalent. I prefer to use.
linseed oil for this purpose and after this saturation the composition is preferably
reheated to such a degree as to resinify the drying oil or the like thus considerably
strengthening the article.
By proceeding as hereinbefore described I utilize the fibre as an entangling
medium to hold the plumbago whilst under treatment and I then convert it into
structural carbon, the carbonizable liquid with which the mixture was originally
saturated being converted into deposit and the oil or the like of the second
impregnation being simply set or resinified so as to strengthen and toughen the
mass.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is
1. A composition of matter, consisting of plumbago, carbonized fibre and a
binder, substantially as herein before specified.
2. A composition of matter consisting of plumbago, combined with structural
and deposited carbon, substantially as herein before described.
. 3. A composition of matter, consisting of plumbago, carbonized fibre, deposited
carbon and an uncarbonized oil or equivalent binder.
4. The process herein described of making a plumbago and carbon composition
the said process consisting essentially in mixing plumbago and fibre, then
subjecting the mass to pressure, then drying the mass, then immersing it in oil or
carbonizable liquid and finally baking the mass to carbonize the said oil or liquid
and fibre, substantially as hereinbefore set forth.
5. The process herein described of making a composition of matter the said
process consisting in making a composition of plumbago, fibre and a carbonizable
Liquid or oil, then subjecting the composition to such a heat as will carbonize the
said fibre and liquid or oil then subjecting the composition to treatment with an
oil binder or the equivalent and then drying or heating the composition so as to
cause the oil or equivalent binder to set or resinify substantially as hereinbefore.
described.
Dated this 6th dox of Cantomba 1000