Improvements in Commutators for Dynamo Electric Machines and Method of Constructing the same.
Year: 1893

page_text: Date of Application, 14th Mar., 1893-Accepted, 15th Apr., 1893
COMPLIM DE CULICATION.
Improvements in Commutators for Dynamo Electric Machines and
Method of Constructing the same.
I, ALEXANDER WILLIAM MESTON, of No. 304 North Eighth Street in the City
of St. Louis, State of Missouri, United States of America, Gentleman, 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 relates to commutators for dynamos and motors, and has for its
object, as a new article of manufacture, a commutator that, in its application, can
be considered as inseparable in its several parts; one that, in its entirety, is adapted
to be used and applied as a single piece; simple and easily constructed; and one
in which, in use, is efficiently insulated between its segments and not likely to
become cross-connected in any way. It consists in the novel features in the
construction hereinafter described.
In the accompanying drawings, in which like characters of reference denote like
parts in the several figures, I have preferably shown the constituent parts of my
commutator on the first sheet-Figures 1 to 12, inclusive, and, on the second sheet,
the several parts assembled, illustrative of the principles of construction and method
of assemblage of the parts illustrated in the first sheet. In the first sheet,
Figures 1, 2, 3, 4, and 12 are illustrative of the metal parts, and Figures 5 to 11,
inclusive, of the insulating parts, of my improved commutator.
Figures 1 and 2 are, respectively, a plan-view and a diametrical section of the
circular or disk supporting-plate;
Figures 3 and 4 are, respectively, a plan-view and a diametrical section of the
annular plate from which the segments are composed ;
Figures 5 and 6 are plan-views, when laid Hat, of the insulation between the
edges of the segmental ring-piece and the disk-plate;
Figure 7 is a plan-view of the annular-shaped insulation-plate used to insulate
the flat side of the segmental ring-piece from the disk-plate;
Figure 8 is a plan-view of the circular insulation-plate placed on the reverse side
of the disk-plate;
Figures 9 and 10 are, respectively, a plan-view and a diametrical section of the
insulation bushing designed to insulate the terminal connections from the disk-plate;
Figure 11 is a plan-view of the insulating strips which are placed between the
different segments;
Figure 12 is a side elevational view of the terminal studs or pins secured to the
different segments of the commutator;
Figure 13 is a diametrical section of the disk-plate and the annular segment-piece,
and the insulation-pieces therebetween, assembled prior to their being secured
together;
Figure 14 is a view similar to Figure 13, showing, however, the parts secured
together, as hereinafter described;
Figure 15 is a plan-view of what is shown in Figure 14, with the additional feature
of having the radial slots sawn, dividing the ring-piece into the different segments;
Figure 16 is a diametrical section of the complete commutator, showing the
terminal pins secured to the segments;
Figure 17 is a perspective view of a disk commutator of my improved form of
construction, illustrating, also, the adaptation of the lip in the edge of the same for
revolubly supporting the commutator, as a whole ;
Figure 18 is a sectional view, taken as on the line 18-18 in Figure 17.
In the drawings, I have illustrated the adaptation of my method of construction

page_text: to the simplest form of commutator, a disk commutator, with which the brushes,
preferably carbon, make contact on the side face thereof-a form to which my
method of construction is peculiarly suited. I do not, however, desire to be under-
stood as limiting myself in such features as are novel and evidently applicable to
the construction of other forms of commutators in general, to their application to
the construction of a disk commutator.
A represents a circular plate, formed as shown in Figures 1 and 2, with a central
perforation A", in instances where the commutator is placed concentric to the shaft
of the machine, to accommodate the same. The piece, as a whole, is formed with a
projecting lip-portion a', by which the commutator, as a whole, is held in place, in
any desirable manner, and, when required, so that the commutator, as a whole, can
be revolved, the plate A acting in the capacity of a supporting-plate for the com-
mutator when assembled. This feature of the adaptation of the lip a¹ to revolubly
support the plate A in place is illustrated in Figures 17 and 18, in which
N represents a projecting portion of the framing of the dynamo or motor to which the
commutator is adapted, in the edge of which is formed a guide-way n, adapted to
receive the lip a¹ and formed concentric with the center of the piece A, the lip a¹
being revolubly retained in place by any convenient means, preferably by the spring
clips N', as shown in Figure 18. In one side face of the plate A is formed the
annular groove A' to receive the segment ring. The side walls of this groove are
vertical in the first instance, as shown in Figure 2, the lower corners, as a being
left slightly filled in, approximately at an angle of forty-five degrees. The material
of the piece A, forming the bottom of the groove A', is perforated at a number of
places, as at a, corresponding to the number of segments it is desired to have in the
commutator when completed. These holes a are placed, preferably, midway between
the side walls of the groove A' and disposed circumferentially so as to divide the
circle on which they are arranged equally. The supporting-piece A, as just
described, is preferably cast in substantially the form described-with the groove A¹,
the axial perforations A", and the holes a-very little finishing being necessary
thereafter to prepare it for the accommodation of the other parts.
B represents an annular piece of which the segments are formed, when the com-
mutator is completed. It is formed with the inner and outer edges inclined or bevelled
off, as at b and 6. The lower corners of these edges are also bevelled off slightly, as
at, to correspond with the corners a" of the bottom of the groove A¹. The ring-
piece B is preferably cast in substantially the form described, and then, subsequently,
coined into the exact form and size. The width of the ring B corresponds,
approximately, to the radial space in the groove A', leaving room, when the parts
are assembled, as hereinafter described, to accommodate the edge insulation strips.
The thickness is such, when the parts are assembled, that there will be material left
above the upper edges of the side walls of the groove A¹ for finishing purposes.
Cand Crepresent the strips of some insulating material, as thin sheet mica,
rubber, or, preferably, vulcanized fiber. They are of a form that, when placed
around and inside, respectively, the piece B, they will conform to the inclined
edges and b¹ of the same, as shown in Figure 13, when the ends of the strips are
brought together. Their shape, as shown in Figures 5 and 6, correspond,
respectively, to the surface of the frustums of cones of which the inclined edges b
and b', of the ring-piece B, form the bottoms. Their width is preferably somewhat
more than the thickness of the ring-piece B.
E represents an annular piece of sheet insulation of dimensions corresponding to
the bottom of the groove A', and, when the parts are assembled, is designed to
insulate the bottom of the ring B from the piece A.
F represents a circular disk of sheet insulation, corresponding in diameter to the
bottom of the piece A to which it is secured when the parts are assembled, as
shown in Figure 16. The sheet, as a whole is formed with holes f, corresponding
to the holes in the piece A, and a central perforation corresponding to the central
perforation A in the piece A.
axial
"
I, Figures 9 and 10, represents a bushing of insulating material, which is secured

page_text: in the holes a in the piece A, preferably by having one end of the bushing threaded
and screwing it into holes a, which, for this reason, are reamed out, and corre-
spondingly threaded, as shown in Figure 16. The bushing I is formed with a
central perforation I' for the accommodation of the terminal pins, to be described.
The sides of the bushings are formed, first, with shoulder i which abuts against the
material of the plate A, or, rather, against the interposed insulation-plate F (see
Figure 16), when the bushing I is screwed home, and, secondly, with the flange-
edge, forming a shoulder for retaining wires in place on the rear side of the
commutator when connected up.
K, Figure 11, represents one of the strips of insulating material which are placed
between the segments in the saw-cuts by which the ring B is divided into different
segments, as hereinafter described.
L, Figure 12, represents a pin, which is preferably screw-threaded on one end, as
the means for securing the pin to the segments, being passed through the insulation
bushings I, and projecting from the rear side of the commutator when the
commutator is assembled, as shown in Figure 16.
The insulation-pieces C, C', and E, are, preferably, made in duplicate, one set
being made of material corresponding to vulcanized fiber, and the other of mica,
and the two used together as one piece, in each instance, placing the mica next to
the ring-piece B, in order that, when used, the other parts of the commutator and
the other insulation will be more efficiently protected from the heat which is
generally developed, to a greater or less degree, in the segmental parts of the
ring-piece B.
The several parts of the commutator are assembled in the following manner :-
The piece A is roughly finished in the lathe on the edge a', and the holes a
tapped. The interior of the groove is, preferably, left rough as it comes from the
sand, in order to bind the parts more rigidly together.
The edges and side faces of the piece B are in good condition as they leave the
coining-press, not requiring any finishing. The bottom of the groove A¹ is
sprinkled with powdered shellac, then the annular insulation sheets E are laid in
the bottom of the groove A', first the fiber and then the mica, and the upper
surface of this sprinkled with powdered shellac. The ring-piece B is placed in the
groove A¹ over the insulation sheets. The sets of insulation-strips C and C¹ are
then placed around and inside, respectively, the edges 6 and 6' of the ring-
piece B-the mica strips next to the ring-piece B-as shown in Figure 13. All the
remaining vacant space in the groove A is then filled in with powdered shellac.
The parts thus assembled are then subjected to heat sufficiently intense to thoroughly
melt the shellac, and, while the shellac is still in its inelted state, they are placed in
a die-press, which, while it firmly holds the insulation-strips C and C¹ in place,
preventing their raising, upsets or turns over, the side walls of the groove A¹ on to
the inclined edges b and 6 of the ring-piece B, firmly securing the same in the
groove A¹, in the manner illustrated in Figure 14. When the shellac cools, the
parts are firmly bound together as one solid piece. These assembled parts are then
chucked, and the front side surface turned off flush, corresponding to what is shown
in Figure 16. They are then, as a whole, chucked in a milling machine, or any
other suitable machine, and radial slots M cut in the front side face of the same to
a depth which will subdivide the ring-piece B into any desired number of similar
segments 1 B, 2 B, etc., as shown in Figure 15. In this instance, the piece is so
chucked as to bring the holes a midway between the cuts or slots M, as shown in
dotted lines in Figure 15. Strips of insulation corresponding to K, after having
been heavily coated with a thick liquid shellac, are then forced in the slots M, and
the whole piece again subjected to the action of a die-press, similar to the one in
which the side walls of the groove A¹ were upset on to the piece B, except that, in
this instance, it only operates on the outer wall of the groove A', tending to force
the segments 1 B, 2 B, etc., radially inward, thereby securely binding the strips K
in the slots M.
Holes are then formed in the under or rear side of the segments 1 B, 2 B, etc.,

page_text: concentrically with the holes a in the supporting-piece A, for the insertion of the
ends of the terminal pins L, the holes being, preferably, screw-threaded, corre-
sponding to the screw-end of the pins L, as the simplest means of securing the
pins to the segments. These holes do not, preferably, extend through to the face
of the segments, in order to leave the face smooth. The circular insulation-plate F
is placed in contact with the under or rear side of the plate A, the holes f in the
plate F registering with the holes a in the plate A. The bushings I are then
screwed home, and the pins L finally secured in place. The use of thus providing
terminals the pins L-from the segments 1 B, 2 B, etc., projecting from the back
of the commutator, is evident, the brushes revolving in contact with the face side,
practically preventing their being led out from that side.
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. As a new article of manufacture, the herein-described commutator for dynamo-
electric machines, consisting in the combination with an annular supporting plate,
provided with an annular groove in one side face of the same, of a segmental
contact-ring secured in the said annular groove and insulated from the said
supporting-plate, substantially as and for the purposes described.
2. As a new article of manufacture, the herein-described commutator for dynamo-
electric machines, consisting in the combination with a disk or annular supporting-
plate, provided with an annular groove in one side face of the same, and a radially-
extending, circumferential lip-portion, of a segmental contact-ring secured in the
said annular groove, and insulated from the supporting-plate, substantially as and
for the purposes described.
3. As a new article of manufacture, the herein-described commutator for dynamo-
electric machines, consisting in the combination with an annular or disk supporting-
plate, provided with means for supporting the same, and an annular groove in one
side face of the same, of a segmental contact-ring secured in the said groove, and
insulated from the supporting-plate, substantially as and for the purposes described.
4. As a new article of manufacture, the herein-described commutator for dynamo
electric machines, consisting in the combination with a disk or annular supporting-
plate provided with a circumferential lip extension, by which the plate is revolubly
supported in place, of a segmental contact-ring secured on one of the side faces
of the same, and insulated therefrom, substantially as and for the purposes
described.
5. As a new article of manufacture, the herein-described commutator, consisting
in the combination with a revoluble supporting-plate, of a series of insulated con-
tact-segments secured to one of the side faces of the said plate, concentric thereto,
substantially as and for the purposes described.
6. As a new article of manufacture, the herein-described commutator for dynamo
electric machines, consisting in the combination with a revoluble supporting-plate,
of a series of insulated contact-segments secured to one side face of the said plate,
concentric to the same, arranged in pairs diametrically opposite each other,
substantially as and for the purposes described.
7. As a new article of manufacture, the herein-described commutator for dynamo
electric machines, consisting in the combination with a disk or annular supporting-
plate, formed with an annular groove in one side face of the same, of a segmental
contact-ring secured in the said groove, an annular insulation-plate in the bottom
of the groove, and insulation-strips between the side walls of the groove and
the edges of the segmental contact-ring, substantially as and for the purposes
described.
8. As a new article of manufacture, the herein-described commutator for dynamo
electric machines, consisting in the combination with a disk or annular supporting-
plate, formed with an annular groove in one side face of the same, of a segmental
contact-ring secured in the said groove, an annular insulation-plate in the bottom

page_text: of the groove, insulation-strips between the side walls of the groove and the edges
of the segmental ring, and insulation-strips between the different segments, substan-
tially as and for the purposes described.
9. As a new article of manufacture, the herein-described commutator for dynamo
electric machines, consisting in the combination with an annular disk supporting
plate, a series of insulated contact-plates secured on one side face of the same, and
insulated terminal connections leading from the contact-segments to the reverse
side of the supporting-plate, substantially as and for the purposes described.
10. As a new article of manufacture, the herein-described commutator for dynamo
electric machines, consisting in the combination with an annular or disk supporting-
plate, of an insulated segmental contact-ring secured on one side face of the same,
insulated terminal connections from the contact-segments protruding from the reverse
side of the supporting-plate, and an insulation-sheet secured on the reverse side of
the supporting plate, substantially as and for the purposes described.
11. The herein-described method of constructing a disk commutator, consisting
in fitting an annular-shaped contact-piece with inclined circumferential edges into a
correspondingly-shaped groove, formed with vertical side walls, in one side face of
a supporting-piece, and in subsequently upsetting the side walls of the groove on
to the inclined edges of the contact-piece, substantially as and for the purposes
described.
12. The herein-described method of constructing a disk commutator, consisting
in imbedding an annular-shaped piece, of which the contact-segments are composed,
formed with inclined edges, in an annular groove in one side face of a disk
supporting-plate, and in securing the annular-shaped piece with interposed insula-
tion in the said groove, by upsetting the side walls of the groove on to the inclined
edges of the same, substantially as and for the purposes described.
13. The herein-described method of constructing a disk commutator, consisting
in imbedding an annular-shaped piece, formed with inclined edges, in an annular
groove formed in one side face of a disk supporting-plate and in securing the
annular-shaped piece, with interposed insulation in the groove, by upsetting the
side walls of the groove on to the inclined edges of the same, and in subsequently
dividing the annular-shaped piece into the separate contact-segments, substantially
as and for the purposes described.
14. The herein-described method of constructing a commutator, consisting in
imbedding the contact-piece, formed with inclined edges, of which the sections are
composed, in a groove formed therefor in the supporting piece, and in securing the
contact-piece, with interposed insulation, in the said groove by upsetting the side
walls of the groove on to the inclined edges of the contact-piece, substantially as
and for the purposes described.
15. The herein-described method of constructing a commutator, consisting in
imbedding the contact-piece, formed with inclined edges, in a groove formed
therefor in the supporting-piece, in securing the contact-piece, with interposed
insulation, in the groove by upsetting the side walls of the same on to the inclined
edges of the contact-piece, and in subsequently dividing the contact-piece into the
3 different segments, substantially as and for the purposes described.
16. The herein-described method of constructing a disk commutator, consisting
in imbedding an annular-shaped piece, formed with inclined edges, in an annular
groove formed therefor, in one side face of a supporting plate, securing the said
annular piece, with interposed insulation, in the groove by upsetting the side walls
of the groove on to the inclined edges of the annular piece, dividing the annular-
shaped piece into a number of segments by radial slots, inserting insulation in the
said slots, and subsequently forcing the segments inwardly by farther upsetting the
outer wall of the annular groove, substantially as and for the purposes described.
17. In a commutator consisting in a supporting-plate, to which the different
sections of the contact-plate are secured, the herein-described means for insulating
the segmental plate from the supporting-plate, consisting in the combination of a
similar sheet, or sheets, of vulcanized fiber, or like material, and mica, the mica

page_text: being placed next to the contact-plate or plates, substantially as and for the
purposes described.
18. In electrical apparatus, the herein-described method for insulating separate
metallic parts from each other, consisting in interposing therebetween one, or
more, sheets of insulating material, sprinkling all contacting parts, insulation and
otherwise, and filling all crevices therebetween, with powdered shellac, subjecting
all the parts thus assembled together to the action of heat, and subsequently
securing the metallic parts together mechanically, substantially as and for the
purposes described.
Dated the 14th day of March 1893.
PHILIP M. JUSTICE,
Chartered Patent Agent for the Applicant.