An Improved Wire Gauze Brush for Dynamos and Motors.
Year: 1895

page_text: Date of Application, 27th Apr., 1895
:: Complete Specification Left, 15th June, 1895-Accepted, 20th July, 1895
An Improved Wire Gauze Brush for Dynamos and Motors.
ARTHUR BURGESS SOAR, Wireworker, and EDWIN WILLIAM COLLIER,
Commercial Traveller, both of 8 Phipp Street, London, E.C. do hereby declare
the nature of this invention to be as follows:-
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The ordinary wire gauze dynamo brush consists of a number of superimposed
layers of gauze (either separate, folded, or rolled and pressed) and for use is cut,
or filed obliquely so that the ends of the various layers come in contact with the
commutator, the result in a brush consisting of 20 layers is that the layer of gauze
next the commutator has the support of the other 19 layers, but the outside layers
not having sufficient support at their ends have a tendency to curl away from the
other layers of the brush and from contact with the commutator (owing to the
rotatory motion of the commutator) thus causing sparking and necessitating
frequent trimming of the brush.
The object of our invention is to prevent this defect, and we do so by folding the
gauze so that the edges of the folds instead of the flat surface of the gauze touch
the commutator. The folded gauze would be subjected to pressure in a mould so
as to form it into a compact mass and the folds kept in place by rivets or
stitching.
We produce a similar and perhaps better result by corrugating the gauze
(corrugations running with the length of the brush) and we pile a number of such
corrugated layers on top of one another with the corrugations resting in one
another. We then subject them to heavy pressure in a mould, the whole being
compressed into a mass of wires in such a manner that none of the layers of gauze
con lagdon from ita naishhanning
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COMPLETE SPECIFICATION.
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An Improved Wire Gauze Brush for Dynamos and Motors,
We, ARTHUR BURGESS SOAR Wireworker and EDWIN WILLIAM COLLIER
Commercial Traveller both of 8 Phipp Street, London, 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 an improved wire gauze brush.
The ordinary wire-gauze dynamo, brush hitherto usually employed consists of a
number of superimposed layers of gauze, either in separate pieces or constituted by
a folded sheet, or by a sheet wound into tubular form and pressed into a flat strip;
the end of such a brush is cut or filed, obliquely so that the ends of all, the layers
may make contact with the commutator. In a brush of this sort having, say,
20 layers, the particular layer of gauze nearest to the commutator axis has the
support of the other nineteen layers, but the other layers considered in succession
[Price Rd 1

page_text: have a relatively diminishing amount of support from their outer neighbours for
that part of each which is in proximity to the commutator, and it is found that
those portions of the layers curl apart and otherwise separate from each other and
from contact with the commutator under the action of the latter, so as to cause
sparking and necessitate frequent trimming.
The object of our invention is to prevent this defect.
According to our invention we construct electrical contact-brushes of wire fabric
in such manner that they have folds or corrugations therein which lie in the
direction of the length of the brush, that is to say folds or corrugations so situated
that each ridge and furrow presents its end at that part of the brush which is to be
in contact with the commutator.
We e corrugate a layer of wire fabric by pressure or otherwise and superimpose
such corrugated layers upon each other, with the corrugations of the contiguous
layers resting in each other and subject the series to heavy pressure in a mould to,
constitute a brush. The corrugations of the different layers interlock and are in
frictional engagement so that no layer can be loosed from its neighbour while in.
use; the layers can if desired be rivetted or stitched together.
Or we fold a sheet of wire fabric into contiguous folds and subject the folded
sheet to pressure in a mould to form a flat bar or thick strip, the width of the
folds approximately equalling the thickness of the bar or strip; in this instance
the folds should preferably be rivetted or stitched together or held in clips or
otherwise prevented from opening out from each other. Or the corrugated' or
folded wire fabric may be produced by weaving the filaments thereof into
corrugated form; a binding-fabric may be incorporated with it to tie, the
corrugations or folds together.
The accompanying drawings illustrate, by way of example the construction of
brushes according to this invention. In the drawings the individual filaments of
each layer of fabric are omitted for the sake of clearness, the layers being indicated
as if they were of thin sheet metal.
Figure 1 is a perspective view of a series of superimposed corrugated layers of
wire fabric such as are hereinbefore referred to prior to their compression.
Figure 2 is a similar view of a brush formed by the compression of the layers
illustrated in Figure 1.
Figure 3 is a perspective view, partly in section of a sheet of wire fabric folded.
into several layers, the compound sheet being corrugated in readiness to be
compressed to form a brush as is shown in
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Figure 4 which is a view in perspective of the completed brush.
Figure 5 is a view, showing a sheet of wire fabric folded into contiguous folds
lengthwise of the brush as aforesaid prior to being compressed.
Figure 6 is a similar view of the sheet of fabric of Figure 5 after compression.
Figure 7 is a perspective view of another construction of brush according to this
invention.
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Figure 8 is a diagrammatic representation of one mode of forming such a brush
as is shown in Figure 7.
Like letters indicate like parts throughout the drawings.
A are the individual layers of wire fabric. B or C is the end of the brush which
is to be presented to the commutator. D are rivets and E is wire stitching to
preserve the compactness of the completed brush; these as aforesaid, need not
always be employed.
The compound sheet of fabric shown in Figures 3 and 4 is so folded that those
edges A of the sheets which are parallel to the folds or compressed corrugations
do not appear at the surface of the brush; the edges of this brush have each a
compressed fold therein additional to those of the other surfaces.
In any of the operations or constructions herein before referred to we may
substitute for a single layer of wire fabric a compound layer produced by suitably
superimposing (astby folding or otherwise) two or more layers. Such a compound
layer is shown in Figure 3.

page_text: In the brush shown in Figure 7 the bottom part F of the brush is of super-
imposed layers of flat non-corrugated fabric, which gives a perfectly smooth
bearing surface, but the back layers Fi are corrugated in folds as shown to stiffen
them and enable them to give good support to the bottom part aforesaid. Such a
brush can be made by feeding a wire strip A (see Figure 8) through corrugated
rollers G and H; the corrugations of one of these rollers (H) are provided upon
only a part of the circumference, the consequence being that the fabric is folded in
the manner indicated (in edge view) in Figure 8, i.e. into a tube corrugated along
one side only. This tube when compressed in a mould becomes a strip such as is
indicated in Figure 7.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is;-
1. The employment of corrugated fabric in the manufacture of electrical contact-
brushes substantially as and for the purpose described.
2. An electrical contact brush having therein superimposed corrugated layers of
fabric substantially as and for the purpose described.
3. An electrical contact-brush having therein superimposed non-corrugated
layers and superimposed corrugated layers substantially as and for the purpose
described.
4. In an electrical contact brush the combination with one or more layers of
corrugated fabric of devices for maintaining the finished shape of the compressed
corrugations or folds substantially as and for the purpose described.
5. An electrical contact-brush constructed substantially as described and
illustrated in Figure 2 or Figure 4 or Figure 6 of the accompanying drawings.
Dated this 12th day of June 1895
ARTHUR BURGESS SOAR.
EDWIN WILLIAM COLLIER.
Boult & Wade,
Agents for the Applicants.
ARTHUR BURGESS SOAR.
EDWIN WILLIAM COLLIER.
Boult & Wade,
Agents for the Applicants.