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

page_text: Date of Application, 12th Jan., 1897
Complete Specification Left, 11th Nov., 1897-Accepted, 18th Dec., 1897
"Improvements in Brush Holders for Dynamo Electric Machines."
We, P. R. JACKSON & Co., LTD., and JOSEPH SLATER LEWIS, both of Salford
Rolling Mills, Manchester, in the County of Lancaster, Engineers, do hereby
declare the nature of this invention to be as follows:
-
Our invention relates to brush holders for dynamo electric machines, and has
for its object to improve the construction of these devices as will be hereinafter
set forth.
In the specification of British Letters Patent No. 6791, dated 2nd April, 1895
a brush holder is described in which the brush is mounted on a carrier pivoted at
the edge of a disc which disc can rotate on a stud fixed to the rocker. The present
invention relates more particularly to brush holders of this description.
According to our invention we provide a casting which is mounted on a stud
on the rocker in the usual way. Pivoted to said casting is the brush carrier to
which the brush is secured by bolts. The brush is arranged so as to slide in a
direction perpendicular to the dynamo spindle, and for this purpose we may pro-
vide a longitudinal slot in the brush through which slot two bolts are passed
securing the brush to the carrier. We may, however, use the ordinary frame
or box carrier, through which the brush is passed and then clamped. To the end
of the brush remote from the commutator a metallic lug is firmly secured by
sweating or otherwise. Rotatably mounted in said lug is a nut having a milled
head with which nut a screw secured at one end to the brush carrier in a position
parallel with the brush can engage. It will readily be understood that by ro-
tating said nut the brush will be caused to move parallel with itself toward or
away from the commutator. For maintaining the brush in position against the
commutator we provide a spring, one end of which is attached to a projection on
the brush carrier, the other end being adjustably secured to a lug or arm on the
casting on which said carrier is pivoted. For maintaining the brush in a position
out of contact with the commutator when desired we may provide a notch in the
carrier with which a spring controlled catch can engage when said carrier is
rotated on its pivot to bring the brush to the desired position. The catch is
adapted to be readily operated to release said carrier whereupon the spring above-
mentioned brings the brush again into contact with the commutator.
In order to avoid loss of energy through the resistance when the current passes
from the brush carrier through the pivotal connection to the casting pivoted on
the rocker, we provide on either side a flexible metallic connection which in its
preferred form consists of a band or loop, made up of a suitable number of thin
strips of copper, secured at one end to the carrier, and at the other end to the
casting above mentioned. A suitable guard or sheath may be provided to prevent
said spring or said laminated copper strips, or both, from coming into contact.
with the commutator if by any chance a breakage of the same should occur.
We wish it understood that we do not confine ourselves to the precise details

page_text: hereinabove described as our improved brush holder may be considerably modified
in various ways, all of which modifications are included in our invention.
Dated this 12th day of January 1897
W. P. THOMPSON & CO.
Patent Agents for the Applcants,
322, High Holborn, London, W.C.
Improvements in Brush Holders for Dynamo Electric Machines."
We, P. R. JACKSON & Co., LTD., and JOSEPH SLATER LEWIS, both of Salford
Rolling Mills, Manchester, in the County of Lancaster, Engineers, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement.-
Our invention relates to brush holders for dynamo electric machines, and has
for its object to improve the construction of these devices as will be hereinafter
set forth.
In the specification of British Letters Patent No. 6791, dated 2nd April, 1895
a brush holder is described in which the brush is mounted on a carrier pivoted at
the edge of a disc which disc can rotate on a stud fixed to the rocker.
'
The present invention relates particularly to brush holders of this description,
and consists in the various means in detail hereinafter set forth whereby the
brush holder is rendered lighter and more efficient, and the presentation of the
brush to the commutator facilitated.
In order that our invention may be clearly understood we will proceed to
describe the same with reference to the accompanying drawings, in which:
Figure 1 is an elevation of one of our improved brush holders.
Figure 2 is a plan of the same.
Figures 3 and 4 are similar views respectively to Figures 1 and 2, shewing a
modification.
screw A¹.
A is a casting which is mounted upon a stud on the rocker (not shewn in the
drawing) in the usual manner being secured in position by means of the pinching
A2 is the lead which is sweated into a suitable orifice provided in said
casting. Bis the brush carrier pivoted at B¹ to the casting A, and C is the brush
which is secured to the carrier by bolts C. The brush is arranged so as to slide
in a direction perpendicular to the dynamo spindle, and is provided for this
purpose with a longitudinal slot C through which the bolts C¹ are passed. Instead
of the carrier shewn we may use the ordinary frame or box carrier through which
the brush is passed and then clamped. To the end of the brush remote from the
commutator à lug D is firmly secured by sweating or otherwise, and rotatably
mounted in said lug is a nut E having a milled head, which nut engages with a
screw B2 secured to the brush carrier B in a position parallel with the brush. It
will be readily understood that the nut E will when rotated move along the screw
B2 toward or away from the carrier B and consequently the brush C will be moved
parallel with itself toward or away from the commutator. F is a spring one end
of which is attached to a projection 133 on the brush carrier, the other end being
adjustably secured by means of a screw F¹ and lock nuts F2 or in any other suitable
manner to a lug or arm A3 on the casting A and a suitable guard or sheath F³
secured to the casting A is preferably provided to prevent the spring from coming
into contact with the commutator in case of breakage.
For maintaining the brush in a pósition out of contact with the commutator

page_text: when desired we provide a notch 13 in the carrier B with which notch the end G
of a lever G¹ pivoted at G2 to the casting A can engage when the carrier is rotated
on its pivot B¹ in the direction of the arrow. G³ is a spring which tends to press
the end G of the lever G, towards the carrier, and thus cause it to engage in the
notch B. By pressing the lever G¹ in the direction of the arrow g the end of the
said lever will be disengaged from the notch, and the spring F will then bring the
brush into contact with the commutator. H is a flexible metallic connection
consisting in its preferred form of a band or loop made of a suitable number of thin
strips of copper secured at one end to the carrier B and at the other end to the
casting A so that a direct electric circuit is provided from the casting to the
brush without the current being required to pass through the pivotal connection
of the carrier.
In the modification illustrated in Figures 3 and 4 the brush C is short and is
secured to a plate J the end of which is turned down to form the lug which carries
the nut E. A slot J is provided in said plate through which pass the bolts for
securing the same to the carrier B. C3 is a steel or hard rolled metal spring plate
for preventing the point of the brush from curling up, said plate is provided with
a slot through which the screw J2 passes so that as the brush wears the plate may
be moved back.
In Figure 4 two narrow brushes secured to a common plate J are shewn and
this construction may also be used with long brushes such as shewn in Figures 1
and 2 said brushes being secured together by the lug D.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is.→→→
1. A brush holder in which the movement of the brush towards and away from
the commutator is effected by means of a nut rotatably secured to a lug attached
to the brush, which nut engages with a screw secured to the carrier along or through
which the brush is arranged to slide, substantially as described.
2. The modification of our invention in which the brush is replaced by a plate
bearing a short brush with or without a spring C³, as set forth.
3. A brush holder constructed and operating substantially as described wijth
reference to the accompanying drawings.
Dated thia 11th doy of Novambon 1907
W. P. THOMPSON & Co.
Patent Agents for the Applicants
Of London, Liverpool, Manchester and Birmingham.