An Improved Method of Making Commutators for Electrical • Machines.
Year: 1899

page_text: Date of Application, 13th Dec., 1899-Accepted, 27th Jan., 1900
COMPLETE SPECIFICATION.
An Improved Method of Making Commutators for Electrical
• Machines.
I, FRITZ KAEFERLE, of 8, Jakobistrasse, Hanover, in the Empire of Germany,
Machine Maker, 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 various methods of making commutators for electrical machines are all
directed towards the same object, namely to bring together quite evenly but as
firmly and unalterably as possible and retain in this position the separate parts
so called "strips" of a commutator (collector) and also the insulating plates
between each two such strips.
The method shown in the accompanying drawings renders this object possible
in a manner not attained by any method previously employed.
Figure 1 is an elevation, and
Figure 1 a plan view of a number of separate strips L as first placed loosely
one against the other, and forming together a ring. An insulating plate of any
suitable material is placed between each two of these strips.
In order to bring these separate parts of the ring all evenly together to the
centre of the same, a solid conical shaped ring R, Figure 1. is placed with its
wider end over the separate parts in such a way that it first encloses them all.
If the ring be then pressed on the separate parts in the direction shown by the
arrows, the said parts move at quite equal distances towards the centre point
of the tanering ring, whilst simultaneously they are pressed firmly one against the
other. When the ring R. Figure 2, has been pressed down almost to the end of
the strips, a second ring R¹ which is also conical or tapering but is made suitably
smaller is pressed in a similar way on the strips, thus causing the latter to be
suitably pressed firmer together. The first ring R thereby becomes loose and
drops down or is pushed down by the ring R and then a third ring R³
and if necessary a fourth ring may be similarly employed until the separate parts
are pressed together so firmly that the ring formed from them must actually be
regarded as one piece, as shown in Figure 3. This ring R remains so long
reated until the collector or commutator according to its form and construction
has been so further treated that the strips are held fast in position by the part
for which they are intended and which in the meantime has been applied, as
shown in Figures 4 and 5. It depends on the applicability of this latter part
or portion of the construction whether the commutator thus formed retains the
great solidity imparted to it by the pressure rings, even after the last ring is
emoved, or whether the strips separate more or less.
When the commutator is so far ready, the last pressure ring R2 must be removed.
For this object the strips are turned down so far inside the ring that the latter
s set free, as shown in Figure 5. This latter procedure is possible in each con-
truction of commutator owing to each commutator having a projection A,
Figure 6, which is formed by the turning down of the strips so far that when the

page_text: pressure ring is removed the commutator may receive its correct form even from
the outside.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
1 claim is:-
The herein described method of making commutators for electrical machines
by pressing together radially the commutator strips or bars by means of taper-
bored rings characterised by rings of diminishing diameter being successively
pressed on the strips which are placed together with insulating material between
them the last ring being only removed when the manufacture of the commutator
is quite completed, substantially as described.
Dated this 12th day of December 1899
WM. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicant.