Improvements in Electrical Resistances.
Year: 1899

page_text: Date of Application, 22nd Dec., 1899
Complete Specification Left, 7th Sept., 1900-Accepted, 22nd Dec., 1900
PROVISIONAL SPECIFICATION.
Improvements in Electrical Resistances.
We, JULIEN DULAIT and OTTO GARBE, both of Charleroi, in the Kingdom of
Belgium, Engineers, do hereby declare the nature of this invention to be as
follows:-
The improved system of electrical resistances in the form of plates or discs
which is the object of the present invention allows of these devices being con-
structed with the advantages of extreme lightness and perfect rigidity, of their
being able to be fixed by the centre without any other mounting, and their
insulation under all vibrations and jolts.
All these advantages are effected by replacing, in the construction of these
plates or discs the strip of flat iron coiled spirally with the interposition of an
insulating strip, up to the diameter desired by a strip of iron formed in a channel
of any suitable section, preferably in the form of a widened trough as shown
in Figure 1 of the accompanying drawing, which shews a series of plates coupled
together partly in section and partly in elevation.
Figure 2 is a front view of one of these discs.
In the drawing a is the iron of channel section coiled into a spiral and
the intermediate insulating strip which together form the resistance in the shape
of an annular disc, the small inner circle of which closely surrounds an insulat-
ing ring c of micanite of corresponding shape. This ring fits in the same
manner a metal hub composed of two strong washers d d with shoulders, put
together and afterwards adjusted under temporary pressure and finally suitably
rivetted together. The large outer circle is previously inserted in a ring of
flat iron e the hooked ends of which engage in the corresponding eyelets formed
by the wings f of the pieces enclosing the ends of the conductors g.
The resistance plates thus constructed, are threaded on a common axle or
shaft the number of the plates corresponding to their purpose and said plates
being electrically connected in the usual manner according to requirements.
As there may be certain difficulties attending the spiral coiling of the iron
formed with channels, we have obviated these by a special process by which the
iron is made channel shaped at the moment of coiling the two strips
which greatly facilitates the manufacture.
n and b
It will be easily understood that a plate of the type described of flat iron,
made channel or arch shaped and spirally rolled gives perfect lateral rigidity by
reason of the channeled circles fitting successively into each other so that any
side displacement is practically impossible. Moreover these plates can be made
very light by reason of the absence of any lateral mounting so that their only
weight is that of the spirals which are self supporting. This ensures their
absolute insulation as in spite of the strongest vibrations they could not make
contact with a lateral covering (absent besides since there is nothing to support

page_text: on account of the individual firmness of the spirals, which are attached exclu-
sively by the centre.
Dated this 22nd day of December 1899.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C.,
Patent Agents for the Applicant.
We, JULIEN DULAIT and OTTO GARBE, both of Charleroi, in the Kingdom of
Belgium, Engineers, 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 improved system of electrical resistances in the form of plates or discs
which is the object of the present invention allows of these devices being con-
structed with the advantages of extreme lightness and perfect rigidity, of their
being able to be fixed by the centre without any other mounting, and their in-
sulation under all vibrations and jolts.
All these advantages are effected by replacing, in the construction of these
plates or discs, the strip of flat iron coiled spirally with the interposition of an
insulating strip, up to the diameter desired, by a strip of iron formed in a channel
of any suitable section, preferably in the form of a widened trough as shewn
in Figure 1 of the drawings accompanying the Provisional Specification, which
shews a series of plates coupled together partly in section and partly in
elevation.
Figure 2 is a front view of one of these discs. In the drawing a is the iron
of channel section coiled into a spiral and the intermediate insulating strip
which together form the resistance in the shape of an annular disc, the small
inner circle of which closely surrounds an insulating ring c of micanite of corre-
sponding shape. This ring c fits in the same manner a metal hub composed of
two strong washers d d with shoulders put together and afterwards adjusted
under temporary pressure and finally suitably rivetted together. The large
outer circle is previously inserted in a ring of iron e flattened on its outer
surface the hooked ends of which engage in the corresponding eyelets formed
by the wings f of the pieces enclosing the ends of the conductors g.
The resistance plates thus constructed, are threaded on a common axle or
shaft h the number of the plates corresponding to their purpose and said plates
being electrically connected in the usual manner, according to requirements.
In order to facilitate the coiling of the strip a the same may be passed through
rollers of suitable contour arranged at a convenient distance from the ring c, said
rollers being arranged to roll said strip a channel shaped."
It will be easily understood that a plate of the type described of flat iron
made channel or arch shaped and spirally rolled gives perfect lateral rigidity by
reason of the channelled circles fitting successively into each other so that any
side displacement is practically impossible. Moreover these plates can be made
very light by reason of the absence of any lateral mounting so that their only
weight is that of the spirals which are self-supporting. This ensures their
absolute insulation as in spite of the strongest vibrations they could not make
contact with a lateral covering (absent besides) since there is nothing to support
on account of the individual firmness of the spirals, which are attached exclu-
sively by the centre.

page_text: Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is:-
1. Improved construction of electrical resistances in the form of plates or
discs characterised by replacing the spirally rolled flat strips of iron by iron
strips hollowed or channelled into any suitable form such as for instance trough-
shaped or V-shaped rounded at the top, substantially as described.
2. The fitting of the plates formed as set forth in Claim I on a hub surrounded
by a micanite ring the hub being formed in two parts rivetted together after
being adjusted by temporary pressure, substantially as described.
3. The insertion of the outer circle of the plates hereinabove described through
a flattened iron ring placed in the hollow of the iron and the bent ends of
which engage in the wings of the enclosing pieces of the conductors, substantially
as described.
4. An electrical resistance constructed substantially as described and illustrated
in the drawings accompanying the Provisional Specification.
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester, and Birmingham.
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester, and Birmingham.