Improvements in Brush Holders for Dynamo Electric Machines and Electric Motors.
Year: 1891

page_text: Date of Application, 22nd Jan., 1891
Complete Specification Left, 22nd Oct., 1891-Accepted, 28th Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in Brush Holders for Dynamo Electric Machines and
Electric Motors.
We, FRANCIS MURRAY NEWTON, of the Newton Electrical Engineering Works,
Taunton, in the County of Somerset, Electrical Engineer and TOM HAWKINS,
of 10 Sydney Terrace, Taunton, aforesaid, Electrician, do hereby declare the
nature of this invention to be as follows:-
This invention has reference to a construction of brush holder for dynamo
electric machines and electric motors by which the pressure of the brushes upon
the commutator and their position in the brush holder can be readily adjusted
whilst the machine or motor is running; and whereby the brushes can be readily
thrown in or out of contact with the commutator and held in the on or the off
attitude.
For these purposes cach brush is preferably carried by a clamp mounted to turn
upon an insulated pin carried by the frame or holder whereby the two brushes are
moved around the commutator. Against the clamp, or in some cases the brush
itself, acts one end of a spring the other end of which is carried by the insulated
pin. To this pin is fixed an arm or bracket through which works an adjusting
screw by turning which the pressure of the spring upon the clamp or brush as the
case may be and consequently the pressure of the brush upon the commutator, can
be adjusted as required. Upon a pin preferably carried by the insulated pin
hereinbefore mentioned, and arranged at the opposite side of the clamp to that upon
which the spring acts, is pivoted an adjustable stop provided with a handle and
formed with two sides or surfaces, the distances of which from the axis of the pin
are different and such that when the stop is turned into one position it will press
against the clamp in opposition to the action of the spring and will hold the brush
away from the commutator, and when turned into a second position say at right
angles to its first position, it will leave the clamp free and permit the same to
assume a position, under the action of the spring, in which the brush will bear upon
the commutator.
In order that the brush may be adjusted within its clamp to compensate for wear
whilst the machine is running, it is formed with an internal screw thread at its rear
end in which works a screw carried by the clamp so that it can be rotated but
cannot move endways. The clamp may advantageously consist of a strip of sheet
metal bent upon itself and passed through a hole in a saddle piece mounted upon
the insulated pin and provided with tightening screws to cause the sheet'metal
clamp to grip a brush placed therein. The bent piece of sheet metal may be
provided with ribs or projections to prevent it moving endways in the 'saddle
piece.
1001

page_text: COME UNIM DIECIFICATION.
Improvements in Brush Holders for Dynamo Electric Machines and
Electric Motors.
We, FRANCIS MURRAY NEWTON, of the Newton Electrical Engineering Works,
Taunton, in the County of Somerset, Electrical Engineer, and TOM HAWKINS
of 10 Sydney Terrace, Taunton, aforesaid, Electrician, 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 has reference to a construction of brush holder for dynamo
electric machines and electric motors by which the pressure of the brushes upon
the commutator and their position in the brush holder can be readily adjusted
whilst the machine or motor is running; and whereby the brushes can be readily
thrown in or out of contact with the commutator and held, in the on or the off
attitude.
For these purposes each brush (preferably carried by a clamp) is mounted so as
to turn upon an insulated pin carried by the frame or holder whereby the two
brushes are moved around the commutator. Against the clamp, or in some cases
against the brush itself, acts one end of a spring, the other end of which is carried
by the insulated pin. To this pin is fixed an arm or bracket through which works
an adjusting screw by turning which the pressure of the spring upon the clamp or
brush, as the case may be, and consequently the pressure of the brush upon the
commutator, can be adjusted as required. Upon a pin, preferably carried by the
insulated pin herein before mentioned, and arranged at the opposite side of
the clamp to that upon which the spring acts, is pivoted an adjustable stop
provided with a handle and formed with two sides or surfaces, the distances of
which from the axis of the pin are different and such that when the stop is
turned into one position it will press against the clamp in opposition to the
action of the spring and will hold the brush away from the commutator, and
when turned into a second position, say at right angles to its first position, it
will leave the clamp free and permit the same to assume a position, under the
action of the spring, in which the brush will bear upon the commutator.
In order that the brush may be adjusted within its clamp (to compensate for
wear) whilst the machine is running, it is formed with an internal screw thread at
its rear end in which works a screw carried by the clamp so that it can be rotated
but cannot move endways. The clamp may advantageously consist of a strip of
sheet metal bent upon itself and passed through a hole in a saddle piece mounted
upon the insulated pin and provided with tightening screws to cause the sheet metal
clamp to grip a brush placed therein. The bent piece of sheet metal may be
provided with ribs or projections to prevent it moving endways in the saddle
piece.
In the accompanying sheet of drawings,
Fig. 1 is an underside view of a brush holder constructed according to this
invention for a dynamo electric machine or electric motor.
Fig. 2 is a side elevation and
Fig. 3 is a top view of the same.
The brush J is carried in a clamp h preferably made of sheet metal. The clamp
is held in a saddle piece P which turns upon the insulated pin S. This pin is fixed
to the frame or holder (not shewn) whereby the two brushes are moved around the
commutator. To cause the brush to press against the commutator with the desired
amount of pressure, there is provided a spring F rivetted or otherwise fixed in a
holder H, which surrounds the pin S but is not rigidly attached to it. The
pressure on the spring F can be varied by the adjusting screw U which passes
through a threaded eye in a bracket L firmly clamped to the pin S. A lock nut M
serves to lock the screw U.

page_text: To remove the brush from contact with the commutator, and also to prevent it
being pressed by the spring with undue force, there is provided a stop I pivotted on
a pin N at the end of an arm E fixed on the pin S. This stop has a handle I,
and has also two sides or surfaces I', I' the distances of which from the axis of the
pin N are different, and such that when the stop is turned into one position (shewn
in dotted lines) it will press the clamp and brush J into the position shewn in
dotted lines, and will remove the brush J from the commutator; when turned into
the other position it will leave the clamp free to assume, under the action of the
spring F, the position shewn in full lines in which the brush will bear upon the
commutator.
The clamp which partly encloses the brush J rests in the saddle piece P and is
prevented from moving endwise by the ribs B B. It can be firmly compressed on
the brush by the thumbscrew A, which passes through a tapped hole in the frame.
There is a slot s in the two parts of the clamp to allow of the passage of the stud
or lug D, which is rigidly attached to the clamp by a nut N. This stud or lug is
screw threaded and works over a screw K. This screw is carried in a bracket G
connected to the clamp; it can rotate in this bracket, but is prevented from moving
endwise by the pin which works in the slot R. By turning the screw K, the
brush can be moved endwise within the clamp to feed it towards or from the
commutator.
The block G besides carrying the screw K is provided with a suitable leg or
projection G for the attachment of a flexible conductor.
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. A brush holder for a dynamo electric machine or electric motor in which the
brush is carried by a saddle piece or part mounted upon an insulated pin such as S
and is acted upon by a spring F free to turn upon the said insulated pin and the
pressure of which against the brush, or against a clamp in which the brush is held,
can be adjusted by a screw substantially as herein described.
2. In a brush holder for a dynamo electric machine or electric motor, the com-
bination of a brush, a nut attached to said brush, a clamp wherein the brush is
carried and a screw carried by the clamp and extending through the nut the
arrangement being such that the brush can be moved longitudinally in relation to
the clamp.
3. In a brush holder such as referred to in Claim 1 for a dynamo electric machine
or electric motor, a stop formed with two sides or surfaces the distances of which
from the axis of the said stop are such that when the stop is turned into one position
it will press the brush away from the commutator, and when turned into a second
position it will leave the brush free, substantially as described.
4. The combination of parts constituting the improved brush holder constructed
arranged and operating substantially as described with reference to the drawings.
1001
F. M. NEWTON.
TOM HAWKINS.
W. Lloyd Wise,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicants.