Improvements in Dynamo Brushes.
Year: 1894

page_text: Date of Application (in United Kingdom), 30th May, 1894
Complete Specification Left. 15th Feb., 1895-Accepted, 16th Mar.,
1895
Improvements in Dynamo Brushes.
I, WILFRID HENRY FLEMING, of 54 Trask Avenue, Bayonne City, in the
County of Hudson, and State of New Jersey, United States of America,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
"
This invention relates to wire gauze brushes for dynamos, and is concerned with
the method of making them, and with certain details of construction by means of
which am enabled to produce a brush greatly superior to any heretofore made.
Wire gauze has been found particularly well suited to the construction of brushes
for this purpose, as being porous. A brush made of it presents a large cooling
surface and consequently will not become overheated. Such a brush also has the
advantage of being somewhat flexible, which enables it to accommodate itself to
the surface of the commutator, and thereby greatly diminishes the wear upon this
part of the machine.
My improvements have for their object an increased flexibility as well as
durability, and to this end 1 arrange the gauze so that the wires cross each
other diagonally across the length of the brush, and subject the brush afterward
to a heavy pressure in a hydraulic press, by which means it is given a compactness
nearly equal to a solid material without destroying its flexibility.
The strip of gauze is cut from the sheet or roll upon the bias so that the
interlacing wires extend diagonally across its length. This is then overwound upon
When sufficient gauze has
a mandrel in a lathe or in any other convenient way.
been wound up to make a brush of the desired size, the mandrel is withdrawn,
and the somewhat loose roll of gauze is put into a mould of the proper size and
subjected to a heavy pressure in a hydraulic press. In this operation the layers of
gauze are pressed into a compact mass, the end of the strip being forced into the layer
below so as to make a smooth joint. The brush therefore needs no sewing or other form
of fastening, such as has always been heretofore found necessary to bind the free
end of the strip of the material. Winding a strip of gauze up in this manner is
the preferable way of using it in forming a brush, but when desired the gauze
may be formed into shape in several other ways. According to one way of doing
this the gauze is cut into pieces of the length of the brush and twice its width,
the piece being cut from the sheet or roll so that the wires extend diagonally across
it. These pieces are then bent in the middle, and the folded leaves thus formed,
put together one within the other in opposite directions. According to another
form of construction the strip of gauze, of a width equal to the length of the brush
is taken and bent into a zigzag. After being formed up in either of these ways
the gauze is pressed into a compact mass as above described.

page_text: After being taken from the mould one end of the brush is dipped in solder and if
desired a metal end plate is soldered on. The other end is bevelled off, to give
it a proper shape for bearing against the commutator.
The mould in which the brush is shaped in the press is preferably made
adjustable as then the same mould may be made available for making brushes of
different widths and thickness.
A brush made in accordance with this Specification is compact and strong, very
durable, and exceedingly flexible. Adapting itself readily to the surface of the
commutator it is always in good metallic contact with it, thereby preventing to a
large extent the sparking so destructive of this part of the dynamo.
Dated this. 30th day of May 1894.
ALLISON BROS.,
Agents for the Applicant.
Improvements in Dynamo Brushes.
1. WILFRID HENRY FLEMING, of 54 Trask Avenue, Bayonne City, in the
County of Hudson, and State of New Jersey, United States of America,
Electrical 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: -
This invention relates to wire gauze brushes for dynamos, and is concerned with
the method of making them, and with certain details of construction by means of
which I am enabled to produce a brush greatly superior to any heretofore made.
Wire gauze has been found particularly well suited to the construction of brushes
for this purpose, as being porous. A brush made of it presents a large cooling
surface and consequently will not become overheated. Such a brush also has the
advantage of being somewhat flexible, which enables it to accommodate itself to
the surface of the commutator, and thereby greatly diminishes the wear upon this
part of the machine.
My improvements have for their object an increased flexibility as well as
durability, and to this end I arrange the gauze so that the wires cross each other
diagonally across the length of the brush, and subject the brush afterward to a
heavy pressure in a hydraulic press, by which means it is given a compactness
nearly equal to a solid material without destroying its flexibility.
In the drawings I have shown the mode of constructing such a brush in sufficient
detail to enable anyone skilled in the art to carry out my invention.
In the drawings,
Figure 1, shows a method of forming up the gauze by winding, and
Figs. 2 and 3, show two other methods of forming the gauze into shape, while
Fig. 4, shows a brush complete.
Referring to Fig. 1 of the drawings A, is the strip of wire gauze from which the
brush is made, and B, a mandrel upon which it is wound. The strip of gauze is
cut from the sheet or roll upon the bias so that the interlacing wires extend
diagonally across its length as shown. This is then overwound upon a mandrel
in a lathe or in any other convenient way. When sufficient gauze has been wound
up to make a brush of the desired size, the mandrel is withdrawn, and the some-
what loose roll of gauze is put into a mould of the proper size and subjected to
a heavy pressure in a hydraulic press. In this operation the layers of gauze are
pressed into a compact mass, the end of the strip being forced into the layer below
so as to make a smooth joint. The brush therefore needs no sewing or other form
of fastening, such as has always been heretofore found necessary to bind the free
end of the strip of the material. Winding a strip of gauze up in this manner

page_text: is the preferable way of using it in forming a brush, but when desired the gauze
inay be formed into shape in several other ways. One way of doing this is shown
in Fig. 2, and another in Fig. 3. As shown in Fig. 2, the gauze is cut into pieces
of the length of the brush and twice its width, the piece being cut from the sheet
or roll so that the wires extend diagonally across it. These pieces are then bent
in the middle, and the folded leaves C, C, D, D, and E, E, thus formed, put
together in the manner shown. In the form of construction shown in Fig. 3, the
strip of gauze A, of a width equal to the length of the brush is taken and bent into
a zigzag as shown. After being formed up in either of these ways the gauze is
pressed into a compact mass as above described.
After being taken from the mould one end of the brush is dipped in solder and
if desired a metal end plate is soldered on as shown at F1, Fig. 4. The other
end is beveled off as shown at G, same figure, to give it a proper shape for bearing
against the commutator.
The mould in which the brush is shaped in the press is preferably made
adjustable as then the same mould may be made available for making brushes of
different widths and thickness.
A brush made in accordance with this Specification is compact and strong, very
durable, and exceedingly flexible. Adapting itself readily to the surface of the
commutator it is always in good metallic contact with it, thereby preventing to a
large extent the sparking so destructive of this part of the dynamo.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, 1 declare that what I
claim is :-
1. A dynamo brush consisting of successive layers of wire gauze formed into
the desired shape, and then compacted by pressure, substantially as specified.
2. A dynamo brush consisting of successive layers of wire gauze in which the
wires are disposed diagonally to the length of the brush, compacted together by
pressure, substantially as specified.
3. The method of forming wire gauze dynamo brushes, which consists in winding
or otherwise disposing the material into the general form of the brush, and then
compacting the material by pressure, substantially as specified.
4. The method of forming dynamo brushes, which consists in overwinding a strip
of wire gauze, the wires in the strip being disposed diagonally to its length, and
then compacting the roll of gauze thus obtained, into a brush of the form and size
desired, by pressure, substantially as specified.
Dated this 12th day of February 1895.
ALLISON BROS.,
Agents for the Applicant.