Improvements in and relating to Brushes and Brush-holders for Constant-current Dynamo-electric Generators and Motors.
Year: 1898

page_text: Date of Application, 15th Aug., 1898
Complete Specification Left, 13th May, 1899-Accepted, 29th July, 1899
Improvements in and relating to Brushes and Brush-holders for
Constant-current Dynamo-electric Generators and Motors.
We, ANTHONY PATTERSON, of 9, Glossop Terrace, Cardiff, Engineer, WILLIAM
HENRY DAVIES, of Cambrian Chambers, Newport, Monmouthshire, Merchant,
and HENRY WHITE, of Derwent, Gold Tops, Newport, Monmouthshire, Engineer,
do hereby declare the nature of this invention to be as follows:-
This invention consists in improvements in and relating to commutator
brushes and brush-holders for constant-current dynamo-electric generators and
motors. Brushes and brush-holders constructed and arranged in accordance
with this invention are of increased simplicity. The brushes are most advan-
tageously situated for collecting current and are constantly held up to the
armature by a yielding and adjustable force. There is less liability to sparking.
The brush-holders, which correspond in number to the poles of the field
magnets of the armature, are composed of cylindrical sockets arranged abreast
and having behind them toothed racks incorporated with or attached to the
cylinders. Engaging with the toothed racks are pawls pivotted in supports
over the racks. Behind the brush points, which are of carbon or other suitable
material and may be burnt-out carbons or remnants from arc lamps, are
pistons from which extend rearwards piston rods, round which are coiled spiral
springs of which one end bears against the piston and the other end against
a block carrying the pawl supports which project upwards through slots pro-
vided for them in the cylindrical sockets. The spiral springs keep the brush
points constantly in contact with the face of the armature and permit the
brushes to recoil or yield slightly backward. Accordingly, the brushes are
held up to the armature by a force which, though yielding, does not withdraw
the brush points out of contact with the armature. The degree of tension
exerted by the springs acting behind the brush pistons is regulated by the racks
and pawls aforesaid which are adjustable so as to provide for wear and tear.
The brush-holders are connected across the armature by a rocking lever, the
points of attachment being insulated. The cables are connected to the holders
at suitable places between the brushes and the points of attachment of the
rocking lever to the brush-holders. The latter are disposed at right angles to
the axis of the armature and have their centres coincident with the centre of
the armature, that is to say, the centre between the two ends of the armature,
and as, as aforesaid, the brush points are equal in number to the poles of the
field magnets, the brushes, in wearing, maintain their relative positions in
contact with the armature and field magnets. Consequently, the brushes, when
once set, in their proper positions, do not require to be re-adjusted.
The arrangement is advantageously adapted for working in either direction,
and for reversing.
1000
6
NICHOLAS WATTS,
Chartered Patent Agent, Bristol.

page_text: Improvements in and relating to Brushes and Brush-holders for
Constant-current Dynamo-electric Generators and Motors.
We, ANTHONY PATTERSON, of 9, Glossop Terrace, Cardiff, Engineer, WILLIAM
HENRY DAVIES, of Cambrian Chambers, Newport, Monmouthshire, Merchant,
and HENRY WHITE, of Derwent, Gold Tops, Newport, Monmouthshire, 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 consists in improvements in and relating to commutator
brushes and brush-holders for constant-current dynamo-electric generators and
motors. Brushes and brush-holders constructed and arranged in accordance
with this invention are of increased simplicity. The brushes are most advan-
tageously situated for collecting current and are constantly held up to the
commutator by a yielding and adjustable force. There is less liability to
sparking.
The brushes, which correspond in number to the poles of the field magnets
of the armature, are carried in frames having cylindrical sockets arranged
abreast in the frames. Toothed racks are incorporated with or attached to the
frames. Behind the brushes, which are of carbon or other suitable material,
and may be burnt-out carbons or remnants from arc lamps, are pistons from
which extend rearwards piston rods, round which are coiled spiral springs which
bear at one end against the pistons and, at the other end, against blocks carry-
ing pawl supports which project upwards through slots provided for them in
the frame. The pawls gear with the toothed racks aforesaid. The spiral
springs keep the brush points constantly in contact with the face of the com-
mutator and permit the brushes to recoil or yield slightly backward. Accord-
ingly the brushes are held up thereto by a force which, though yielding, does
not withdraw the brush points out of contact therewith. The degree of tension
exerted by the springs acting behind the brush pistons is regulated by adjust-
ing the pawls in the racks aforesaid.
The brush-holders are connected across the commutator by a rocking lever,
the points of attachment of which to the holders are insulated. The cables are
connected to the holders at suitable places between the brushes and the points
of attachment of the rocking lever to the brush holders. The brushes are
arranged at right angles to the centre line of the armature, that is to say, at
right angles to a line projected through the centre of the armature from either
end thereof. The longitudinal axis of each socket and, consequently, of each
brush point c, would, if sufficiently extended, cut the centre line of the arma-
ture. The brushes, as they wear, do not alter their position relatively to the
field magnets. Consequently, the brushes, when they have once been set in
their proper positions, do not require to be re-adjusted.
Referring to the accompanying sheet of drawings, Fig. 1 is a part elevation
and part section illustrating our improved brush-holder mechanism. The sec-
tional part is taken on the line r,, Fig. 2, which is a plan. Fig. 3 is an end
view, partly sectional, the sectional part being taken on the line y, y, Fig. 2.
The brushes consist of holders, being a pair of frames a arranged one on
each side of the commutator b and having cylindrical sockets in which are
placed the brush-points which are of carbon or other suitable material and
may be remnant carbons from arc lamps. At their front ends the brush-
points are in contact with the periphery of the commutator. The brushes

page_text: Each
correspond in number to the poles of the field magnets of the armature. Behind
each brush-point c and in contact with its rear end is a piston d from which
extends rearwards a spindle e capable of axial travel through the block f
against the inner face of which bears one end of a spring g coiled around the
spindle e. The other end of the spring g bears against the piston d.
block has secured to it a lug h supporting a pair of pawls i which engage
with toothed racks ; formed in the frame a on either side of slots provided
in the frame. For each brush-point there is, as shown in the drawing, a sepa-
rate pair of racks and pawls, and a separate slot and separate pawl support.
By the provision of the pawls i and racks the wear of the brush-points is
taken up when required, and by the same means the degree of tension exerted
by the springs g acting behind the pistons is regulated. The brush-points
are held up to the face of the commutator b by the springs g acting behind
them providing a constant and yet flexible feed. Renewals of brush-points
can be effected without necessitating stoppage of the generator. The centres
of the brush points on one side of the commutator bare not coincident with
those on the other side, so that the abrasion or wear of the periphery of the
commutator is equalized over the whole area.
The holders are carried on a rocking lever 1, on which, when slid thereon
into place, they are clamped by the bolts m passed through the flanges of the
cap n. The lever is insulated at o. The holders a are adjustable on the lever
so that, as the commutator becomes reduced in diameter through wear, the
holders can be moved inwards accordingly towards it to take up the wear.
The cables are connected to the holders a by the binding screws q.
Having now particularly described and ascertained the nature of this inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is :-
1. Bruskies for use in connection with the commutators of constant-current
dynamo-electric generators and motors; consisting of frames such as a having
the brush-points separately and adjustably carried therein, the arrangement
being such that each brush-point is kept in contact with the commutator by a
continuously-maintained flexible force, substantially as hereinabove described.
2. In brush-point holders such as are referred to in the preceding claim;
means for adjusting the brush-points in the holders; said means consisting of
pawls such as i, racks such as; and lugs such as h, the latter being connected
to blocks such as f slung on spindles such as e fixed to pistons such as d situated
behind the brush-points, the parts being constructed, arranged, and operating
substantially as hereinabove described with reference to the accompanying
drawing.
3. Means for adjusting the brush-holders so as to take up wear of the com-
mutator and so to adapt the brushes to provide for reduction in the diameter
of the commutator; said means consisting of the rocking lever, flanged cap n,
and clamping bolts m; the parts being constructed, arranged and operating
substantially as hereinabove described with reference to the accompanying
drawing.
Da 10 dave of If.... 1900
NICHOLAS WATTS,
Chartered Patent Agent, Bristol.