Improvements in Dynamo Machines.
Year: 1891

page_text: Date of Application, 5th Jan., 1891
Complete Specification Left, 28th Oct., 1891-accepted, 28th Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in Dynamo Machines.
I, ROOKES EVELYN BELL CROMPTON of the Arc Works Chelmsford in the
County of Essex, Engineer do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in the collecting apparatus of dynamo
machines, and more particularly to the collecting brushes or rubbers which rub upon
the surface of the commutator, and collect the currents therefrom.
My improved collecting rubbers consist of a springy arm made up of several
layers of hard copper sheet or other suitable material properly superimposed so as
to form a taper spring similar to one half of a carriage spring, that is to say the
hard drawn metal sheets forming the springy arm take the place of and act precisely
in the same manner as the steel leaves of which the ordinary carriage spring is
made up. My object of so arranging the plates is to provide a highly conducting
springy arm with the parts so arranged that the free extremity has the least possible
weight. In order that the respective plates forming the springy arm should bear
properly against one another I give to each of the plates before they are cramped
together a certain curvature, the curvature of the longer plates being of greater
radius than those of the short plates. In this way the free extremities of each of
the plates bear and rub against the back of the plate next below it.
On the free extremity of the springy arm I mount a removable contact which
may be of copper anti friction metal, plumbago, carbon or other material suitable
for this purpose in the following manner. The rubbing piece is formed into long
rods having a trapizoidal or dovetail shaped section so that when suitable lengths
corresponding to the width of the springy arm are cut off they can be secured to
the springy arm by being thrust into position from one side and there held by a
series of claws or projections stamped out of and bent out so as to stand at the
The section of the rubbing
required angle from the surface of the springy arm.
piece being of trapizoidal form with the larger side next to the plate is held by
these claws if they are so bent and contrived as to hold it dovetail fashion. The
cross section of the rubbing piece may be varied from the plain trapizoid in any
suitable manner so that the claws or projections from the springy arm can hold it
in position and at the same time leave the rubbing surface free.
In some cases I form the holding part of the springy arm out of two plates which
can slide in relation to one another in such manner that the claws or projections at
the end of them can be made to grip the rubbing piece with more or less firmness
and afterwards secured in position by screws or clamps or suitable means which
prevent the two plates from sliding in relation to one another after the rubbing
piece is in position.
Deted the 5th day of January 1891.

page_text: COMPLETE SPECIFICATION.
Improvements in Dynamo Machines.
I, ROOKES EVELYN BELL CROMPTON of the Arc Works, Chelmsford, in the
County of Essex, Engineer do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
My invention relates to improvements in the collecting apparatus of dynamo
inachines and more particularly to the collecting brushes or rubbers which rub upon
the surface of the commutator and collect the currents therefrom.
My improved collecting rubbers consist of a springy arm A. Figs. 1 and 2 made
up of several layers L L L of hard copper sheet or other suitable material properly
superimposed so as to form a taper spring similar to one half of a carriage spring,
that is to say the hard drawn metal sheets forming the springy arm take the place of
and set precisely in the same manner as the steel leaves of which the ordinary carriage
spring is made up. My object of so arranging the plates is to provide a highly con-
ducting springy arm with the parts so arranged that the free extremity has the least
possible weight. In order that the respective plates forming the springy arm should
bear properly against one another I give to each of the plates before they are cramped
together a certain curvature, the curvature of the longer plates being of greater radius
than those of the short plates. In this way the free extremities of each of the plates
bear and rub against the back of the plate next below it. On the free extremity
of the springy arm I mount a removable contact C which may be of copper, anti-
friction metal, plumbago, carbon or other material suitable for this purpose in the
following manner. The rubbing piece C is formed into long rods having a
trapizoidal or dovetail shaped section so that when suitable lengths corresponding
to the width of the springy arm are cut off they can be secured to the springy arm
by being thrust into position from one side and there held by a series of claws or
projections P stamped out and bent out so as to stand at the required angle from
the surface of the springy arm. The section of the rubbing piece being of
trapizoidal form with the larger side next to the plate is held by these claws if they
are so bent and contrived as to hold it dovetail fashion. The cross section of the
rubbing piece may be varied from the plain trapizoid in any suitable manner so
that the claws or projections from the springy arm can hold it in position and at
the same time leave the rubbing surface free, as for example the form shown in
Fig. 3.
In some cases I form the holding part of the springy arm out of the two
plates T T one or both of which can slide in such manner that the claws or pro-
jections at the end of them can be made to grip the rubbing piece C with more or
less firmness and afterwards be secured in position by screws or clamps or suitable
means which prevent the two plates from sliding in relation to one another after the
rubbing piece is in position.
Instead of stamping the claws or projections out of the springy arm itself they
may be formed of a separate piece of metal and attached to the springy arm by any
suitable means.
Various forms of such attached claws are shewn in Figs. 5, 6 and 7.
may use any of the above forms of the improved collector in conjunction with
the ordinary form of brush collector used in continuous current dynamos.
For example Fig. 8 shews such a collector C in advance of an ordinary brush B
both resting on the surface of the commutator M.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1 For the collecting apparatus of dynamo electric machines, the arrangement
or combination of parts of rubbers and their cunnents.
as to provide
80
ጠ
hill

page_text: conducting springy supporting arm consisting of a series of overlapping plates
secured one against another the free extremity having the least possible weight all
substantially as and for the purpose set forth.
2: For rubbers of the collecting apparatus of electric machines contact pieces
made, mounted and applied on springy arms formed of a combination of assembled
overlapping plates, substantially as and for the purposes hereinbefore set forth.
3: The manufacture and use of rubbers for the collecting apparatus of dynamo
electric machines formed and applied, substantially as set forth in respect of
Figure 8.
Dated the 28th dex of October 1891
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.