Improvements in Brush Holders for Dynamo Electric Machines.
Year: 1897

page_text: Date of Application, 21st June, 1897-Accepted, 31st July, 1897
COMPLETE SPECIFICATION.
Improvements in Brush Holders for Dynamo Electric Machines.
I, JAMES HENRY YEARSLEY, a citizen of the United States, residing at No. 44 North
Fourth Street, in the City of Philadelphia, in the County of Philadelphia, and State
of Pennsylvania, 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:—
My invention has relation to a holder for the brush of a dynamo or similar electric
machine in which the carbon or other material of which the brush is made must be
pressed closely against the commutator to prevent "sparking"; and in such
connection it relates particularly to the construction and arrangement of such
a holder.
The principal object of my invention is to provide in a brush-holder a feeding or
pressing device for the brush by means of which the brush is held closely and with a
uniform pressure upon the service of the commutator so that all "sparking" or
tendency to "sparking" is avoided.
To this end my invention consists in a brush holder wherein the brush is adapted
to be fed and in which the brush is pressed towards the commutator by means of two
hinged or pivoted arms, each adapted to rest at or near the sides of the brush, said
arms being united by a bridge-piece through which is adapted to pass a threaded pin
or bolt, one end of said pin or bolt being under tension of a spring and the other end
passing through the bridge and adapted to receive one or more adjusting nuts, whereby
the tension of the spring is brought directly upon the bridge and transmitted
equally therethrough to each arm.
My invention further consists in a brush holder for dynamos constructed and
arranged in substantially the manner hereinafter described and claimed.
The nature and scope of my invention will be more fully understood from
the following description taken in connection with the accompanying drawings
forming part hereof, in which
Figure 1, is a top or plan view of a brush holder embodying main features of my
invention and illustrating the same applied to two brushes.
Fig. 2, is a side elevational view of the same, the right hand end of the holder
being partly sectioned and having certain parts removed for the purpose of more
clearly illustrating the invention; and
Fig. 3, is a cross sectional view of the holder end of a portion of the
commutator.
The
Referring to the drawings A, represents the commutator of a dynamo electro
machine of the ordinary type and B, represents a box or holder for the brushes a,
which box is also of the usual construction and may be held in operative position
with respect to the commutator by the frame B¹, or in any well known manner.
box B, is centrally apertured or recessed as at b, and in this recess the brush a, is
adapted to enter and from which it is adapted to project against the commutator A,
substantially as illustrated in Fig. 3. From one side of the box B, projects a
bracket b', to which is pivoted as at 62, two arms d, extending over and down upon
the upper end of the brush a. These arms d, are united together by a cross piece or
гр .

page_text: bridge d'. Through the bridge d', extends a screw threaded pin or bolt d³, one end
of which is secured to a spring e, which spring is also secured to the box as at e¹.
The other end of the pin or bolt d², projects through the bridge d and is adapted
to receive adjusting and jam nuts d³ and d, which when advanced on the pin or
bolt d², increase the tension of the spring e, and thereby through the bridge d¹, and
arins d, increase the pressure brought upon the upper end of the brush a, and serve
to force said brush into closer engagement with the commutator A. The' brush a,
by preference is reinforced or strengthened by the side plates f, united to each other
and clamped against the brush by means of a bolt or bolts f¹.
By the arrangement above described it will be readily understood that the pressure
exerted upon the brush is evenly distributed on its upper surface and hence the
brush is held firmly and evenly upon the commutator A, and "sparking" or tendency
to "sparking" is reduced to a minimum. As the pressure of the spring e, is
not exerted directly upon the arms d, or any one of said arms, but upon the;
cross piece or bridge d', which is practically integral with both arms, it is obvious.
that each arm will always be under a constant and uniform pressure and neither
arm can press with more or less force upon the brush.
Having now particularly described and ascertained the nature and objects of my
invention and in what manner the same is to be performed, I declare that what I
claim is:-
1. In a brush holder for dynamos, a box in which the brush is adapted to be
fed towards the commutator, to arms pivoted at each end to the box and having
their free ends resting upon the brush, a cross piece or bridge uniting said arms,
and a spring adapted to depress said bridge towards the box, whereby the arms are
caused to press upon the brush with a constant and uniform pressure, substantially as
described.
2. In a brush holder for dynamos, a box in which the brush is adapted to be fed
towards the commutator, two arms pivoted at one end to said box and having their
free ends resting upon the brush, a cross-piece uniting said arms, a threaded pin
passing through said cross-piece, a spring securing one end of said pin or bolt to the
box, and adjusting and jam nuts adapted to advance and retract on said pin throngh
the cross-piece, substantially as and for the purposes described.
Dated at Philadelphia, Pennsylvania, this 31st day of May A.D. 1897.
JAMES HENRY YEARSLEY.