IMPROVEMENTS IN ELECTRO-MAGNETS
Year: 1884

page_text: I WILLIAM LEFFLER of N° 366 Compton Buildings Goswell Road Clerkenwell
in the County of Middlesex Clockmaker do hereby declare the nature of my
Invention for "IMPROVEMENTS IN ELECTRO-MAGNETS" to be as follows: —
My invention relates to Electro Magnets in which it is of importance that the
armature shall not remain attracted after the electric current has ceased to flow
and as the armature does sometimes remain attracted commonly called "armature
sticking "I have invented a simple device for overcoming such attraction.
In carrying my invention into practise I provide permanently magnetised steel
armatures to be alternately attracted and repelled according to the change of
polarity in the electro-magnets such change of polarity being caused by reversing
alternately the direction of the electric current by means of a commutator which
I provide.
This commutator is interposed in the electric circuit so that by a slight movement
of the same the current is reversed causing a change of polarity in the electro-
Magnets whereby the armature is attracted and repelled. Sometimes I provide
soft iron armatures round which is coiled insulated wire through which the electric
current passes, converting the soft iron into temporary magnets to be attracted
and repelled; should the current in the armature be reversed then the current in
the electro-magnets must not be reversed.
WILLIAM LEFFLER.

page_text: I WILLIAM LEFFLER of 366 Compton Buildings Goswell Road Clerkenwell
in the County of Middlesex Clockmaker do hereby declare the nature of my
Invention for IMPROVEMENTS IN ELECTRO-MAGNETS 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 Electro-Magnets in which it is of importance that the
armature shall not remain attracted after the electric current has ceased to flow,
and as the armature does sometimes remain attracted commonly called "armature
sticking" I have invented a simple device for over coming such attraction.
In carrying my invention into practice I provide permanently magnetised steel
armatures to be alternately attracted and repelled according to the change of
polarity in the electro-magnet or magnets such change of polarity being caused by
reversing alternately the direction of the electric current by means of a commutator.
The commutator is interposed in the electric circuit so that by a slight movement
of the said commutator the electric current is reversed, causing a change of polarity
in the electro-magnet or magnets whereby the armature is alternately attracted or
repelled.
Sometimes I provide a soft iron armature or armatures round which I coil
insulated wire and the electric current passing through the said wire converts the
soft iron into a temporary magnet or magnets to be alternately attracted and
repelled according to the change of polarity. If the current in the armature coils
is reversed then the electric current in the electro-magnet or magnets must not be
reversed, and if the electric current in the electro-magnet or magnets is reversed
then the electric current in the armature coils must not be reversed.
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 clain is-
An electro-magnet furnished with a permanently magnetised steel armature or
armatures, the electric current in the said electro-magnet to be alternately reversed
which will cause the said armature or armatures to be alternately attracted or
repelled according to the change of polarity in the said electro-magnet by which
means it will be impossible for the said armature or armatures to remain attracted
when like poles in armature or armatures and electro-magnet or magnets are
opposite to each other.
2. An electro-magnet furnished with soft iron armature or armatures round which
are coiled insulated wire through which wire the electric current flowing converts
the soft iron into a temporary magnet or magnets and the electric current either in
the armatures or in the electro-magnet (but not in both at the same time) to be
alternately reversed, the said armature or armatures to be alternately attracted and
repelled according to change of polarity by which means it will be impossible for
the armature or armatures to remain attracted when like poles in armatures and
electro-magnet are opposite to each other.
1 100th day of Santember 1884.