Improvements in the Manufacture of Dynamo-brushes.
Year: 1898

page_text: Date of Application, 10th Nov., 1898-Accepted, 25th Feb., 1899
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Dynamo-brushes.
We, JOHANN CHRISOSTIMUS LEISSING, Manager, and CHARLES LOUIS HIEBL,
Superintendent of Rennersdorf, Lower Austria, in the Austro-Hungarian Empire,
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 follow-
ing statement:-
This invention relates to the manufacture of dynamo brushes and its object is
to make certain improvements in the processes for the production of these brushes
so that the essential features of cheapness in production and economy in working
are obtained.
To produce a good dynamo brush it has been found by experiment that the
following qualities are necessary (apart from the hardness of the material employed
according to the hardness or kind of metal used in the commutator segments against
which the brush rubs), the material must be a good conductor so as to avoid heat-
ing of the brush, the brush itself must be of thoroughly elastic construction so as
to secure a satisfactory and permanent contact with the commutator and thus pre-
vent sparking when collecting the current, and finally the very essential feature
of constructing the brushes so that premature wearing out is obviated.
Up to the present time dynamo brushes have not fulfilled these various require-
ments as when one of the requirements were fulfilled it was usually at the expense
of the other.
The dynamo brush produced by the improved process forming the subject matter
of this application fulfills all the requirements herein before stated.
The process consists in the following:-Fine wire gauze of phosphor or sodium
bronze is taken with from 70 to 90 wires to the square centimeter, and strips are
cut therefrom in such a direction that the wires of the gauze lie diagonal to the
direction or length of the strip. The strips thus produced are annealed one or
more times in any well known manner and then carefully flattened in rolls or other
suitable mechanism. These flattened strips are rolled up in the usual manner and
then pressed or manipulated into the desired shape and it is found that the brush
gives a highly elastic permanent and good conducting results.
It is to be clearly understood that the essential features of the improved process
are cutting the required strips from a fine wire gauze or web in such a manner
that the direction of the strip is diagonal to the direction of the threads in the
gauze and rolling flat these strips so cut to produce a thin sheet like piece finely
divided by its wires and of great elasticity.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. The improvements in the manufacture of dynamo brushes consisting in pro-
ducing the material for the brushes by cutting up fine wire gauze of suitable
materials such as phosphor or sodium bronze into longitudinal strips so that the

page_text: wire of the gauze lies diagonal to the length of the strip and further rolling the
said strips so produced, the whole process giving a finely divided and highly elastic
metal web with diagonal threads and thus fulfilling the advantages of good con-
duction, sparkless collecting, and durability.
30.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.