Improvements in Commutator Brushes or Contact Pieces for Electrical Apparatus.
Year: 1887

page_text: Date of Application, 27th Jan., 1887
Complete Left, 25th Oct., 1887
Complete Accepted, 25th Nov., 1887
PROVISIONAL SPECIFICATION.
Improvements in Commutator Brushes or Contact Pieces for
Electrical Apparatus.
We, DRUITT HALPIN of 9 Victoria Chambers, Westminster in the County of
Middlesex, Engineer, and ILLIUS AUGUSTUS TIMMIS of 2 Great George Street,
Westminster in the County of Middlesex, Engineer do hereby declare the nature of
this invention to be as follows:-
The brushes or contact pieces of dynamo electric machines, electrical motors or
other electrical apparatus are subject to the disadvantage of wear by frictional contact,
resulting in the roughening or grooving of the contact surfaces both of the brushes
and of the commutator whereby the efficiency of the commutator is impaired.
According to our present invention we obviate this defect by imparting to the
commutator brushes or to their holders a slight lateral to and fro motion in the
direction of the axis of the commutator, by which means a uniform frictional action is
insured over the whole of the surfaces in contact, which are thus maintained perfectly
smooth and efficient. The arrangement for imparting such lateral to and fro motion
to the brushes may be variously modified, thus according to one arrangement we fix
on the commutator shaft a worm wheel gearing with a worm whose spindle has crank
pins on its ends connected by links to the brush holders, the supports of which are
arranged so that they are free to rock or slide laterally somewhat. Cr we fix on the
commutator shaft bevil wheels gearing with other bevil wheels or spindles having
cranks actuating the brushes as before, or the spindle rotated by the commutator shaft
may carry eccentrics or tappets bearing against one side of the brush holder which is
pressed against it by a spring on the opposite side.
13
11 h of Januo 1887
ABEL & IMRAY,
Agents for the Applicants.

page_text: Improvements in Commutator Brushes or Contact Pieces for
Electrical Apparatus.
We DRUITT HALPIN of No. 9 Victoria Chambers Westminster in the County of
Middlesex, Engineer, and ILLIUS AUGUSTUS TIMMIS of 2 Great George Street,
Westminster in the County of Middlesex, 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:-
The brushes or contact pieces of dynamo electric machines, electrical motors or
other electrical apparatus are subject to the disadvantage of wear by frictional contact,
resulting in the roughening or grooving of the contact surfaces, both of the brushes
and of the commutator whereby the efficiency of the commutator is impaired.
According to our present invention we obviate this defect by imparting to the
commutator brushes or to their holders a slight lateral to and fro motion in the
direction of the axis of the commutator, by which means a uniform frictional action is
insured over the whole of the surfaces in contact, which are thus maintained perfectly
smooth and efficient, the framing carrying the brush holders is at the same time so
arranged as to allow of its being adjusted into any desired angular position relatively
to the commutator, in order to obtain for the brushes the most suitable angle of lead.
The arrangement for imparting such lateral to and fro motion to the brushes may be
variously modified, thus according to one arrangement we fix on the commutator
shaft a worm wheel gearing with a worm whose spindle has crank pins on its end
connected by links to the brush holders, the supports of which are arranged so that
they are free to rock or slide laterally somewhat. Or we fix on the commutator shaft
bevil wheels gearing with other bevil wheels on spindles having cranks actuating the
brushes as before, or the spindle rotated by the commutator shaft may carry eccentrics
or tappets bearing against one side of the brush holder which is pressed against by a
spring on the opposite side.
Fig. 1 of the accompanying drawings shews a side elevation of a dynamo electric
machine, the commutator brushes of which have a lateral to and fro motion imparted
to them according to our invention while they are at the same time capable of being
adjusted to the most suitable angle of lead. Fig. 2 shews a plan, Fig. 3 shews an end
view and Fig. 4 shews a cross section on line X X Fig. 1.
The shaft A of the commutator B has an extension beyond its bearing C, on which
is formed a worm A¹ that gears with a worm wheel D, carried by a framing E. This
framing is fitted loose upon the end of the shaft A and upon a cylindrical projection
of the bearing C, so that it can be turned in either direction thereon, but it can also
be fixed in position by means of a clamping-disc F secured by screws F1 to the end
face of the bearing, so that by screwing up the screws, the disc F is made to clamp
the part E of the framing tight against a shoulder on the bearing at a. Upon
cylindrical parts at each end of the bearing are fitted rings G G¹ capable of sliding

page_text: to and fro thereon, the two rings being firmly tied together by rods H. H, the ends of
which enter eyes E on the framing E, in which they can slide to and fro.
The ring G has two opposite brackets which carry the commutator brushes I and
which also have handles JJ by which the ring can be turned on the bearing. The
axis of the worm wheel D has a crank, which is connected by a rod K to a pin on
one of the rods H, so that by means of the slow rotary motion imparted to the worm
wheel 1 by the worm A', a slow to and fro motion is imparted to the rings G G¹ upon
the bearing C, whereby a corresponding to and fro motion is imparted to the brushes 1
upon the commutator B as this revolves. In order to set the brushes with the required
lead in the first instance, the screws F₁ are loosened, whereupon the rings G G¹
together with the frame E and worm wheel D can be turned into any desired position;
upon then tightening the screws F' again, the frame is secured, and as the rods H
slide through the eyes E2 of the framing, the rings G G₁ and consequently the
brushes are also prevented from shifting from the angular position to which they have
been adjusted.
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 we do not claim
broadly the method of imparting a lateral to and fro motion to commutator brushes,
but what we claim is :-
Mounting the brushes of contact pieces of moving commutators upon sliding or
rocking frames to which a to and fro motion is imparted by worm wheel or other
gearing from the commutator shaft such that the brushes are made to slide to and fro
upon the surface of the commutator in a direction at a right or other angle to its
motion, the framing carrying the brush holders being at the same time capable of
angular adjustment, for obtaining the niost suitable lead for the brushes, substantially
as herein described.
Dated this 25th day of October 1887
ABEL & IMRAY,
Agents for the Applicants.