Improvements in the Construction of the Cores of the Armatures of Electro Motors and Dynamo Machines.
Year: 1887

page_text: Date of Application, 12th Dec., 1887
Complete Specification Left, 30th Aug., 1888
Complete Specification Accepted, 5th Oct., 1888
Improvements in the Construction of the Cores of the Armatures of
Electro Motors and Dynamo Machines.
I, MORITZ IMMISCH, of 119 Torriano Avenue, Camden Town, London, in the
County of Middlesex, Electrician, do hereby declare the nature of this invention to be
as follows:-
In building powerful electro motors or dynamo machines a difficulty has presented
itself in practice with regard to preventing faults or short circuits in the coils of the
armatures consequent upon the very great strain put upon the insulation through
excessive torque, especially in motors where this torque sometimes attains enormous
proportions. It has been found that however solidly the cores may be built up and
however rigidly they may be attached to the spindle by the means hitherto employed,
frequent hitches occur through the strains becoming excessive and loosening parts
which should remain rigid.
My invention relates principally to that class of armatures of electro motors and
dynamo machines in which the cores are built up of a series of plates, and it consists
in improved means for securing such plates to the armature spindle in such a manner
as to enable them to be made perfectly solid with such spindle."
For this purpose I place two collars or bushes on the armature spindle, both of
them being mounted on keys secured to such spindle, and one being capable of sliding
longitudinally thereon, while the other abuts against a shoulder formed on the spindle.
In the outer surface of each collar or bush a series of equidistant longitudinal grooves
(preferably three in number) is cut, such grooves being inclined inwards, that is to
say they are deeper at their inner than at their outer ends.
Each groove receives one end of a key, the part entering such groove being inclined
on its under surface in the same way as the bottom of the groove, in which it is
capable of sliding. These keys serve to secure the plates forming the armature core
rigidly and solidly on the spindle, for which purpose each of such plates has a central
hole, and in the metal surrounding the hole notches are cut in positions corresponding
to those of the keys, which latter enter such notches. The part of the spindle beyond

page_text: the collar or bush which can slide on the spindle, is screw threaded to receive a nut,
by turning which such collar or bush is moved inwards towards the other or stationary
collar or bush, whereby the inclined surfaces of the grooves in such bushes or collars
force the keys which fit therein outwards, and thus force their outer edges more
firmly into the notches in the plates of the core, until same are rigidly and firmly
held.
If in consequence of excessive torque (to which especially electro motors are often
subjected), a loosening of the plates should occur, it is then only necessary to actuate
the nut by means of a spanner, and so again force the movable collar or sleeve further
inward, and consequently the keys further outwards, thus again firmly tightening up
the whole. Means are thus provided for periodically ascertaining if any loosening
has taken place, and of remedying same if it has.
As the core plates are thin should some of them become looser than others, when
the keys are forced outwards the tighter ones will spring sufficiently to enable the
whole of the plates to be again made perfectly tight and solid with the spindle. The
great pressure which is exerted on the keys by means of the nut causes the whole to
not only be firmly fixed, but in addition imparts a degree of elasticity to the different
parts, and enables them to yield to any excessive strains to which they may be
subjected.
The end plates of the armature core are as usual made thicker than the others, and
in them slots are cut to receive the keys and keep them firmly in their radial positions,
while at the same time permitting them to move outwards.
I have described my invention as applied to armature cores which are built up of
plates, but same may also be applied to armature cores which are built up of wire,
the expanding keys in that case being utilized to exert pressure on the tubing which
is always used for winding the wire on, so that the latter may be tightened should it
become loose.
Dated this 10th day of Danember 1987

page_text: Improvements in the Construction I
Electro Motors and Dynamo Machines.
I, MORITZ IMMISCH, of 119 Torriano Avenue, Camden Town, London, in the
County of Middlesex, Electrician, 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 :-
-
In building powerful electro motors or dynamo machines a difficulty has presented
itself in practice with regard to preventing faults or short circuits in the coils of the
armatures consequent upon the very great strain put upon the insulation through
excessive torque, especially in motors,. where this torque sometimes attains enormous
proportions. It has been found that however solidly the cores may be built up and
however rigidly they may be attached to the spindle by the means hitherto employed,
trouble frequently occurs through the strains becoming excessive and loosening parts
which should remain rigid.
My invention relates principally is that class of armatures of electro motors and
dynamo machines in which the cores are built up of a series of plates, and it consists
in improved means for securing such plates to the armature spindle in such a manner
as to enable them to be made perfectly solid with such spindle.
The method of carrying my invention into effect is illustrated in the accompanying
drawings, in which Fig. 1 is a longitudinal section of my improved armature and
Fig. 2 a transverse section of same, with the field shown in elevation.
In carrying out my invention I place two collars or bushes b, b', on the armature
spindle e, both of them being mounted on keys c secured to such spindle, and one
being capable of sliding longitudinally thereon, while the other abuts against a
shoulder d formed on the spindle. In the outer surface of each collar or bush b, b¹,
a series of equidistant longitudinal grooves (preferably three in number) is cut, such
grooves being inclined inwards, that is to say they are deeper at their inner than at
their outer ends.
Each groove receives one end of a key a, the part entering such groove being
inclined on its under surface in the same way as the bottom of the groove, in which
it is capable of sliding. These keys a serve to secure the plates forming the armature
core rigidly and solidly on the spindle, for which purpose each of such plates has a
central hole, and in the metal surrounding the hole notches are cut in positions
corresponding to those of the keys, which latter enter such notches. The part of the
spindle e beyond the collar or bush 6 which can slide on the spindle, is screw threaded
to receive a nut f, by turning which such collar or bush is moved inwards towards
the other or stationary collar or bush b, whereby the inclined surfaces of the grooves
in such bushes or collars force the keys a which fit therein outwards, and thus force
their outer edges more firmly into the notches in the plates of the core, until same are
rigidly and firmly held.

page_text: If in consequence of excessive torque (to which especially electro motors are often
subjected), a loosening of the plates should occur, it is then only necessary to actuate
the nut by means of a spanner, and so again force the movable collar or sleeve b¹
further inward, and consequently the keys a further outwards, thus again firmly
tightening up the whole. Means are thus provided for periodically ascertaining if
any loosening has taken place, and of remedying same if it has.
As the core plates are thin should some of them become looser than others, when
the keys a are forced outwards the tighter ones will spring sufficiently to enable the
whole of the plates to be again made perfectly tight and solid with the spindle e.
The great pressure which is exerted on the keys a by means of the nut causes the
whole to not only be firmly fixed, but in addition imparts a degree of elasticity to
the different parts, and enables them to yield to any excessive strains to which they
may be subjected.
The end plates of the armature core are as usual made thicker than the others, and
in them slots are cut to receive the keys and keep them firmly in their radial positions,
while at the same time permitting them to move outwards.
I have described my invention as applied to armature cores which are built up of
plates, but same may also be applied to armature cores which are built up of wire, the
expanding keys in that case being utilized to exert pressure on the tubing which is
always used for winding the wire on, so that the latter may be tightened should it
become loose.
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
I claim is
The employment of collars, keyed to an armature spindle, one of which collars is
capable of longitudinal movement thereon, while both collars are formed with grooves
the bottoms of which are inclined or tapered, and which grooves receive keys having
correspondingly inclined surfaces so that the longitudinal movement of one of the
collars will cause the keys to move outwards, and by acting upon the plates or wire
of which the armature is built up will firmly hold and tighten same, while exerting a
yielding or elastic pressure thereon, substantially as specified.
Dated this 27th day of August 1888.
ALLISON BROS.,
Agents for the Applicant.