IMPROVEMENTS IN TELEGRAPHIC INSTRUMENTS
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by Georges Duberu at the Office of the
Commissioners of Patents on the 25th March 1876.
GEORGES DUBERU, of Allipore, in the Suburbs of Calcutta, in the East Indies,
Electrician. IMPROVEMENTS IN TELEGRAPHIC INSTRUMENTS."
";
According to this Invention I pivot an armature at its centre and place it not
over or in front of the electro-magnet poles as hitherto done but cross-wise between
them so that both ends of the armature are projecting right and left as far as or
farther than the poles of the electro-magnet, and in close proximity to them.
These extremities are therefore acted upon at the same time normally by equal and
opposite forces tending to make the armature revolve about its centre and hence
causing no increase of pressure or friction on the bearings when the armature is
attracted. Moreover, this peculiar disposition of the armature is highly favorable
to the excitation of induced magnetism. The said armature is brought back by two
antagonistic equal springs or magnetic poles acting on both ends of the armature in
opposite directions, tending to make it revolve the contrary way to the one caused
by the attraction of the electro-magnet, and therefore also occasioning no strain
whatever on the bearings. On one end of the armature works a long index by
means of a short projecting lever, which multiplies considerably the motion and
renders it readable by sight when through any cause the strokes are not sufficiently
audible. One end of the armature is also furnished with a translation spring.
These parts compose the instrument in its most complete state. By the removal of
either index translating spring or one of the antagonistic springs simpler instruments
are made to answer any special purpose.
In polarized instruments, and especially in polarized relays, the mechanical arrange-
ment remains the same; but the action of the two antagonistic springs is replaced.
by two magnetic or electro-magnetic poles.
Generally the new electro-magnet and armature with the few necessary additions
to constitute an instrument will be applicable whenever an ordinary electro-magnet
has been hitherto employed, and it is therefore meant to be used in connection with
any electro-magnetic telegraph instrument, and from the perfection of its performance
it also allows of new applications.
The nature of the said Invention will be best understood by comparing the mode
of action of the ordinary electro-magnet with this new one.
[Dion 931

page_text: The armatures or tongues in either case are supposed to be equally heavy.
With ordinary instruments.
With my improved instrument.
The forces to be overcome before the armature moves are as follows:-
1. Friction on bearings due to weight
of axle.
2. Friction on bearings due to weight
of beam.
3. Friction on bearings due to weight
of armature.
4. Friction on bearings due to the
traction of antagonistic spring whose
resulting pressure equals at least twice
the weight of the armature.
|
1. Friction on bearings due to weight
of axle. In many cases there is no axle
hence no friction.
2. Nil.
3. Friction on bearings due to weight
of armature and small projecting piece.
4. Nil.
5. Nil.
When the electro-magnet attracts the armature-
5. Friction on bearings due to at least
twice the weight or force necessary to
stretch the antagonistic spring.
Inertia to be overcome and tending to retard the motion of the armature—
6. Inertia due to the mass of the
beam.
7. Inertia due to the mass of the
armature.
6. Nil.
7. Inertia due to the mass of the
armature and projection thereon. This
inertia, however, is much less than in
ordinary instruments, as the velocity of
any part of the mass, besides the very
ends, diminishes rapidly towards the
centre, whereas in the other any part
moves necessarily at the same velocity.
Case in which a horizontal tongue is used as an armature. forces to be overcome