The Manufacture and Production of Compositions of Matter more. especially intended for use for Bearings, Packing, Projectile Covers, Commutator Brushes, or other Purposes where Surfaces are in Frictional Contact.
Year: 1891

page_text: Date of Application, 16th June, 1891-Accepted, 18th July, 1891
COMPLETE SPECIFICATION.
The Manufacture and Production of Compositions of Matter more.
especially intended for use for Bearings, Packing, Projectile
Covers, Commutator Brushes, or other Purposes where Surfaces
are in Frictional Contact.
I, PHILIP HENRY HOLMES of Gardiner in the County of Kennebee and
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 relates to an improved composition of matter, adapted more
especially for the manufacture of journal bearings, packings, projectile covers,
commutator brushes, and various other articles where two parts come
frictional contact.
into
According to my invention I take plumbago, preferably in a finely divided
condition and floated so as to obtain as pure an article as possible, and I mix
this with fibre also preferably in a finely divided state. The relative proportions
of these two materials may vary somewhat according to the character of the
article to be produced, but in all cases the plumbago is in excess in order to get
the most efficient lubricating surface consistent with strength. For journal box
bearings or spindle bearings for instance, I can use proportions extending from
four parts by weight of plumbago to one of fibre up to thirty five parts by
weight of plumbago to one of fibre. These proportions may be varied, however,
and still good results be obtained.
Where wood, or equivalent vegetable fibre, is used, it is finely divided and
mixed with the plumbago in water, and the composition, in a morc or less
plastic condition, is then placed in a mould corresponding in shape with the
article to be produced. It is therein subjected to powerful pressure for the
purpose of expelling the water from the material and for moulding the mass
into the desired form. The fibre acts as a felting and entangling material for
the fine plumbago and at this moulding stage of the process, moreover, it acts
somewhat as a filter, retaining the plumbago and preventing it from escaping
with the water through the perforations of the mould.
After the article has been moulded under pressure, and most of the water expelled,
it is removed from the mould and completely dried in any suitable or convenient
manner. I then impregnate and saturate this moulded and dried article with a
drying oil, and for this purpose it is best to immerse the article in a bath of hot oil.
This mass may be more or less saturated with oil according to the use for which the
completed article is intended. For some purposes it is preferable to thoroughly
saturate and impregnate the mass with oil, while in other cases a lesser degree of
saturation will be sufficient.
The oil I prefer to use is linseed oil, but I do not restrict myself to the use of any
particular kind of oil.
It is sometimes preferable to place the oiled article in a closed vessel, heated to a
sufficient temperature to assist in driving the oil into the interstices of the composi-
tion, but the presence of the fine fibres throughout the body of plumbago is an
important element in getting the oil thoroughly into the whole mass of the moulded
article.
The material thus thoroughly impregnated with the drying oil is then placed in a
suitable retort or oven and is there subjected to a sufficient degree of heat to harden,
set and solidify the mass by developing a resinous film throughout the intimate

page_text: mixture of fibre and plumbago. In other words the drying oil impregnates the
fibre and enters the interstices between the particles of plumbago and fibre and
operates to cover such particles with a coating which becomes hard and has a
binding, solidifying and hardening effect upon the mass, and renders it of sufficient
strength to become self-sustaining and capable of withstanding the hard usage and
.severe strains to which it may be subjected.
The main body or basis of the composition produced is the plumbago, which
material is specially adapted for bearings for journal boxes and other articles
subjected to frictional wear, owing to the excellent lubricating qualities of plumbago
and its capacity for long continued use without wearing away to any appreciable extent
The plumbago is preferably in such excess in the composition that on a casual
inspection of the completed article the fibre and oil are not noticeable.
The fibre, which is intimately combined with the powdered plumbago, and which
is preferably soft wood fibre, finely divided, serves as a binder to thoroughly bind
together the finely powdered plumbago in the desired form and to impart solidity
and strength to the completed article. This is due to the fact that the finely
divided fibre when intimately mixed with the powdered plumbago forms a bond
which confines the plumbago against displacement, and as the fibre and the hardened
or resinified drying oil ramify throughout the entire mass, there will be imparted to
it a firm and cohesive character and a hardness which enables the article to preserve
its form and shape, although in use it may be subjected to great weight strain or
wear.
The moulded and hardened journal bearing of the composition described is
furthermore, owing to the presence of the varnish, both water proof and oil-proof,
which is a valuable and important feature, as it enables journals or spindles to run
in oil or water without injury to the plumbago bearing.
The mould I prefer to use for the purposes of my invention has passages for the
escape of the liquid, with which the plumbago and fibre are first mixed, as it is
pressed from the compound, these passages being so arranged in the mould in
relation to the bearing surface of the article that the liquid will be drained from the
compound transversely at or about right angles to the said bearing surface in such
a manner that the fibres will be turned end on to the bearing surface.
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.
First. A moulded and hardened composition for bearings or other purposes the
said composition consisting essentially of plumbago, wood or other vegetable fibre
and drying oil, the plumbago being in excess, substantially as hereinbefore
described.
Second. A composition of matter consisting essentially of a mixture of plumbago,
fibre and a drying oil moulded into the desired form and solidified and hardened by
heat, substantially as hereinbefore set forth.
Third. A composition of matter consisting of a base of plumbago, a binder of
finely divided wood or other vegetable fibre and a drying oil moulded under pressure
into the desired form and solidified and hardened by heat, substantially as herein-
before set forth.
Fourth. A moulded composition for bearings or other purposes the said com-
position consisting of plumbago, fibre and hardened linseed oil, the plumbago being
in excess, substantially as herein before described.
Fifth. A moulded composition for bearings or other purposes the said com-
position consisting of plumbago, wood fibre and linseed oil in about the proportions
substantially as hereinbefore stated.
Sixth. The process hereinbefore described of forming composition articles
containing plumbago the said process consisting in mixing plumbago and fibre with
a liquid so as to form a semi-fluid mass, introducing the compound into a mould and

page_text: compressing it therein to remove the liquid therefrom, drying the moulded mass and
saturating or impregnating it with an oil, and drying and hardening the mass
substantially as hereinbefore described.
Seventh. The hereinbefore described process of forming bearings of plumbago
and fibre the said process consisting in making a plastic compound of plumbago,
fibre and liquid, in the proper proportions, then compressing the compound so as
to force the liquid therefrom in a direction transversely to the face of the
bearing, whereby the fibre in the bearing in following the channels of escape of
the liquid is caused to assume such a position that the ends of the fibre will be
presented at the face of the bearing, substantially as hereinbefore described.
Dated the 16th day of June 1891.
J. H. JOHNSON & Co.,
Agents.