IMPROVEMENTS IN FRICTION BREAKS AND IN FRICTIONAL DRIVING MECHANISM
Year: 1885

page_text: Mechanism.
CHARLES JACKSON Engineer 134 Robin Hood Chase Nottingham do hereby
declare the nature of my invention for IMPROVEMENTS IN FRICTION BREAKS AND
IN FRICTIONAL DRIVING MECHANISM to be as follows:-
The object of this invention is to obtain a frictional holding between surfaces
without causing undue heating or injury to the surfaces. The invention is
applicable both, to breaks for retarding and arresting the rotation of wheels or
the movement of other parts of machinery and also to frictional driving clutches
where a surface in rotation or movement is required to impart like movement to
another surface. I form the break or holding surface of hardened asbestos.
My method of forming the hardened asbestos blocks is to mix with asbestos a
resinous or other binding material, to then mould it to the desired form and to
expose it to great pressure and sufficient heat to render insoluble or change the
nature of the binding material.

page_text: Mechanism.
I, CHARLES JACKSON Engineer 184 Robin Hood Chase Nottingham 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 this invention is to obtain a frictional holding between surfaces
without causing undue heating or injury to the surfaces. The invention is
applicable both to breaks for retarding and arresting the rotation of wheels or
the movement of other parts of machinery and also to frictional driving clutches
where a surface in rotation or movement is required to impart like movement to
another surface I form the break or holding surface of hardened asbestos.
My method of forming the hardened asbestos blocks is to mix with asbestos a
resinous or other binding material, to then mould it to the desired form and to
expose it to great pressure and sufficient heat to render insoluble or change the
nature of the binding material.
In order that my said invention may be more fully understood and readily
carried into effect I will proceed to explain the same more in detail.
The invention is applicable wherever a frictional holding is required between two
surfaces, whether it be for the purpose of checking the movement of one of them
or for the purpose of transmitting movement from one to another. A common
example of the first case is the application of a brake block to a railway wheel
with the object of checking the movement of a train. My invention is applicable
in this case, and I proceed as follows:-
'
I employ a metal brake block and I form a cavity or preferably a series of
cavities in the acting surface of the block. I prefer to form these cavities say each
about one inch in diameter and slightly undercut, or larger within than at the
Burface and the depth may conveniently be about a quarter of an inch. I then
proceed to fill these cavities with prepared asbestos I can use the asbestos in the
state of a loose fibre but I prefer to employ a fabric woven from asbestos cords or
threads; I saturate the fibre or fabric with a solution of shellac in methylated
spirit; the solution which I use by preference is about the consistence of honey.
Sometimes I use black stoving varnish. I dry the fibre or fabric so prepared
and if employing the fabric I cut it into discs or pieces of a size to enter the
cavities. I fill each cavity with these discs laid one upon the other and I con-
solidate the asbestos by heavy pressure in a suitable press.
I use for this purpose
a plunger so formed as to leave the asbestos standing somewhat higher than the
face of the brake block-I then place the brake block in an oven heated to a tem-
perature of 350 degrees or thereabouts and I leave it in the oven for several hours.
The asbestos then becomes thoroughly hardened. When the operation is terminated
the brake block is ready for use.
Another case in which my invention is applicable is in friction clutches for
driving machinery. In such clutches a disc or coned surface driven by a steam
engine or other motor is pressed against corresponding surface in order that the

page_text: motion imparted by the motor may be transmitted by the mechanism to the axis
on which the second disc or surface is carried, and to the parts geared therewith.
The discs or surfaces I employ are metal and I turn a groove or grooves in the
face of one or other of them-The groove should be somewhat undercut.
I prepare asbestos fibre or fabric in the manner already described and I fill with
it the groove in the face of the disc or coned surface exposing the fibre to heavy
pressure and in such manner as to leave it standing somewhat higher than the face
of the disc or cone-I then put the disc or cone in an oven for several hours and
heat it to a temperature say of 350 degrees-When the disc or cone leaves the
oven I if necessary turn the asbestos to a true face and the disc is then ready for
use to form part of a frictional driving clutch as already described.
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 :-
My improvements in friction brakes and in frictional driving mechanism con-
sisting in the employment therein of asbestos consolidated and caused to cohere by
heavy pressure and by the aid of shellac or other like material, such prepared
asbestos being forced into cavities in the face of metallic frictional surfaces and
afterwards hardened by exposure to heat substantially as described.