Improvements in Brake Shoes.
Year: 1896

page_text: Date of Application, 22nd Dec., 1896-Accepted, 22nd May, 1897
Improvements in Brake Shoes.
I, JOHN MCLACHLAN, of No. 167 Dearborn Street, Chicago, Cook County, State
of Illinois, United States of America, Gentleman, 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 brakes, particularly to such as are employed on railway
trains and the like, and has for its object particularly to provide a new and improved
brake shoe, to be used in connection with such brakes, and which among other
advantages will have greater frictional power than the ordinary metallic brake shoe
and which also will have greater durability than the ordinary fibrous brake shoe.
My invention is illustrated in the accompanying drawings, wherein
Figure 1 is a side view of a brake embodying my invention ;
Figure 2 is a front or face view of the same;
Figure 3 is a section on line 3-3, Figure 1 ;
Figure 4 is a side elevation of a modification;
Figure 3 is a face view of Figure 4.
Like parts are indicated by like letters throughout the several figures.
The brake shoe broadly considered consists of a fibrous material such as wood,
the fibre of which has not been ruptured or broken, but which remains in substantially
its natural condition, the said fibrous material having been compressed to an enormous
degree or until the albuminous material in such fibre is expressed and the fibres are
flattened and forced into close and intimate contact with each other. In other words,
I employ as the shoe a fibrous material, preferably wood, in its natural state so far as
the continuity of the fibres is concerned, but in a new state or condition to the extent
that the softer portions of such fibrous material are expressed and the fibres proper
are left in a solidified, compact and enormously compressed condition.
I prefer to expose the ends of the fibre to the wheel, or in other words make the
bearing surface transverse to the line of the fibres; though this is perhaps not
necessary in every case, and not desirable under all conditions.
This material used in a brake shoe differs from pulp substances, such as paper, in
that it presents the natural fibre in its practically natural state; and experience shows
that such fibre is far more lasting and effective than if the fibre has been broken up,
reduced to pulp and otherwise treated.
On the other hand this material is superior to
natural fibrous substances, as for example wood in its natural state, in that it is free
from the soft substances such as the albuminoid and other matters which weaken and
soften the material and permit it to wear rapidly and decay readily, and which also in
some instances and to a degree may prevent its having the same frictional power. The
fibre in the natural wood uncompressed is, so to speak, suspended in a substance in which
it has a certain freedom of motion; whereas when compressed and such substance
expressed the fibres are brought into the most intimate relation and, practically, have
no individual motion. In the case of elm wood, which I have treated and used very
extensively in this manner on railway trains, the compression is usually to about
one-half the bulk of the natural wood, and the product is an extremely hard close-
grained, close textured material. This substance is also found by experience to be
superior to metal, in that it begins the work of braking the wheel as soon as it is
brought in proximity thereto, and therefore the frictional effect is applied and taken
off gradually as distinguished from the effect of an ordinary metallic brake shoe.

page_text: It is desirable to subject most woods to some treatment before compressing them in
order to facilitate the compression and prevent injury to the material. Any suitable
treatment that will bring about this result may of course be used, and I will only
attempt to point out one particular treatment to which the wood may be subjected.
I wish to be understood as not limiting myself to any one method of treating the wood,
as any other treatment which will allow the wool to be greatly compressed in the
manner herein described will answer as well. The natural wood either hard or soft is
first subjected to the cooking action of a hot fluid either in a liquid or gaseous form,
as by water boiling or steaming, so as to expand it, open its pores, soften the fibres,
and dissolve the saps and juices thereby bringing it into favorable condition for the
- next step in the treatment. In cases where the wood has been air or kiln-dried so as
to drive off the juices and saps the above process may be omitted.
The cured wood is next inimersed in oil, preferably oil of penetrating quality which
will harden when it becomes cold. As the oil penetrates the wood better when hot,
I immerse the wood in oil which has been heated, or if the oil is cold when the wood
is put in, such oil is heated at some time during the immersion. I prefer to submerge
the wood in the oil while still hot from the water, steam or other treatment, and them
to heat the oil until it boils gently. By this treatment the albuminous matter in the
wood is either dissolved or so softened as to insure its being expelled when the
compression takes place. At the same time the fibres are so softened that they
may be readily brought into very intimate contact with each other so as to form a
dense-textured product. I have found mineral oils to be peculiarly fitted for this use
on account of their great penetrating quality. After the wood has been substantially
saturated with oil, I subject it, preferably while hot, to powerful pressure applied
to the sides of the fibres, the pressure being sufficient to reduce the thickness or
width of the wood, preferably to one-half or one-third of its original thickness or
width. The press employed for this purpose is preferably heated before or at the
time the pressure is applied and should remain heated during the entire operation.
The degree of compression and length of time during which the pressure is applied
will of course depend upon the nature of the wood. The compression expels not
only the softened albumen but also any surplus oil which may have been taken up
by the wood. After the wood has been compressed sufficiently, it is cooled in any
desirable manner before releasing the pressure. The pressure is then released and
the wood remains in this compacted and reduced state with the fibres in intimate
contact as if by natural growth, there being no tendency for the wood to expand
or resume its original size or form. In some cases it may be desirable to force
the oil into the wood with pressure. If desired the substance or material when
ready for use in the brake shoe or during the process of compression and treatment
may be further water-proofed, though it is usually rendered substantially water-proof
by such compression. The wood may also be treated in any other desirable manner
to make it fire proof. Wood subjected to this treatment when used as a brake shoe
has many advantages over any material now upon the market as has been before
stated.
A block of wood C of the desired shape is fastened in any convenient manner to the
frame F, as for example, by the screws C. This frame is provided with projecting
lugs which are provided with holes adapted to register with holes in projecting lugs
on the brake block B when the shoe is in position, the frame and brake block being
connected together by the removable piece E. Said brake block is connected to the
brake beam A by means of a bolt or in any other desirable manner. In some cases
it may be desirable to provide the side plates or supports D D as shown in Figure 4.
I prefer to have two blocks C C separated at their middle, there being driven between
them the block C as shown, whereby the parts are securely attached to each other and
held in position. When a shoe of this material is used, it immediately begins to brake
whatever the condition of the wheel when applied thereto, and produces a more
effective brake than any now upon the market.
When wood in its natural state is brought against a rapidly moving body, a large
amount of heat is generated by the friction and the wood is burned or charred so as to

page_text: change its character and cause it to crumble and become worthless. I have found by-
experiment that the wood herein described will stand this heat without in any manner
becoming charred or changed in its nature.
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:
1. A brake shoe comprising a metal portion adapted to be properly supported, and
a friction portion adapted to engage the car wheel and to be held by the supporting
metal portion, said friction portion consisting of fibrous material treated and arranged.
and used substantially as shown and described and for the purpose specified.
2. A brake comprising a shoe adapted to make contact with the wheel, said shoe
composed of highly compressed wood in which the natural fibres remain unbroken and
in their natural arrangement, the softer substances having been removed so that the
fibres lie in a closer and more intimate contact and relation than when in the natural..
state, substantially as herein shown and described.
3. A brake shoe comprising a highly compressed homogeneous block of wood in
which the natural fibres remain unbroken and in their natural arrangement, and from
which the softer substances have been largely removed so that the fibres lie in a closer
and more intimate relation than when in the natural state, the wood so treated as to
be proof against charring by the heat developed when in contact with the wheel,.
substantially as herein shown and described.
4. The brake shoe herein shown and described.
DL: 180
CRUIKSHANK & FAIRWEATHER,
Chartered Patent Agents,
62 St. Vincent Street, Glasgow, Agents for the Applicant...