Improvements in the Manufacture of Composition Bearings, Packings, Projectile Guides or Rings, or analogous articles, applicable also for use as Electric Conductors.
Year: 1892

page_text: Date of Application, 6th Sept., 1892-Accepted, 8th Oct., 1892
COMI LEID DI MULTIATION.
Improvements in the Manufacture of Composition Bearings, Packings,
Projectile Guides or Rings, or analogous articles, applicable also
for use as Electric Conductors.
I, 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 :-
The object of my invention is to form a composition of matter in which
plumbago and fibre are elements, and in which an oil binder is used to make the
completed article homogeneous. The composition of matter can be used for such
purposes as bearings, packings, projectile guides or rings, and in any place where
two parts come into frictional contact, and can also be used as a conductor of
electricity.
In carrying out my invention I take plumbago, preferably in a finely divided
state and floated so as to obtain it in as pure a condition as possible, but other
grades of plumbago may be used if a very pure condition of the plumbago is not
required for the article to be produced.
then mix with this plumbago, divided fibre, that is, fibre which has been
reduced to a pulp (which may be effected by any ordinary or suitable process) the
plumbago and fibre being mixed in a suitable pulping engine by preference, so as to
thoroughly incorporate the fibres with the plumbago. The proportion of plumbago
to fibre depends upon the use to which the composition is to be put, but in the
majority of cases the plumbago will be largely in excess of the fibre.
The liquid which I prefer to use in mixing the plumbago and fibre, is water in
sufficient quantity to make a paste, but I preferably add a small quantity of finely
divided granular mineral substance, which serves, with the fibre, as a filtering
medium when the composition is compressed in the mould. The material which I
prefer to use for this purpose is an inert material, such as gypsum, which material
I have found to answer well although it will be understood that other granular
mineral substance will accomplish the purpose.
The compound is then introduced into a mould having perforations, to allow for
the escape of the liquid, and provided with a plunger for compressing the material
in the mould.
I preferably pump the material into the mould, after which the plunger is forced
into the mould until the material is compressed to the degree required and the
water or other liquid is driven off from the composition through the perforations in
the mould. The compressed composition is then removed from the mould and
dried so as to expel all the moisture therefrom, and is then immersed in a bath of
drying oil or any suitable fluid varnish, and allowed to remain until it is
impregnated or saturated with the oil or varnish, and to facilitate this impreg-
nation it is preferable that the bath of oil or varnish be hot, the mass being
more or less saturated with oil or varnish, depending upon the character of the
composition required.
The oil or varnish which I prefer to use is linseed oil, but I do not restrict
myself to any particular kind of oil or varnish, as various kinds of drying oil or
composition of oil, or semi-drying oils, copals, pyroxiline varnishes, and other oil, or
spirit varnishes may be used."
After such treatment it is sometimes preferable to place the article in a closed
vessel, heated to a sufficient temperature to assist in driving the oil or varnish into
the interstices of the composition, the presence of the fine fibres throughout the
body of the composition being an important element, as they serve to lead the fluid
oil or varnish into the moulded article.

page_text: The moulded compound thus treated with oil or varnish is placed in a suitable
retort or oven and is therein subjected to a degree of heat sufficient to set, solidify
and harden the mass by developing a resinous film throughout the intimate mixture
of fibre and plumbago, the film being due to the action of the heat upon the
binding oil or varnish which thus exercises the desired binding, solidifying and
hardening effect upon the mass and renders it of sufficient strength to become self
sustaining.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
IT
1. The process herein described of making a plumbago composition for bearings,
electric conductors or other articles the said process consisting in mixing plumbago,
fibre and an inert mineral substance in liquid, then expelling the liquid by pressure,
and then impregnating the mass with a liquid binder, substantially as hereinbefore
described.
2. The process herein described of making a plumbago composition for bearings,
electric conductors or other articles the said process consisting in mixing plumbago,
fibre, and gypsum with liquid, then expelling the liquid by pressure, then impreg-
nating the compressed composition with an oil or varnish binder and afterwards
drying the composition to set the binder, substantially as hereinbefore described.
Dated this 6th day of September 1892.
J. H. JOHNSON & Co
Agents.