Improvements in Magneto Electric Machines for Igniting Fuses and for similar Purposes.
Year: 1888

page_text: ' al
01 Application, 9th June, 1888
Complete Specification Left, 8th Mar, 1889
Complete necification Accepted, 4th May. 1889
120
PROVISIONAL SPECIFICATION.
Improvements in Magneto Electric Machines for Igniting Fuses and
for similar Purposes.
I, EUGENE DUCRETET, of the firm of E Ducretet & Co. Scientific Instrument
Manufacturers, of 75 rue Claude Bernard Paris, France, do hereby declare the nature
of this invention to be as follows
The present invention consists essentially in the lamination of the armatures of soft
iron upon which are arranged the bobbins of wie of the magneto electric fuses or
exploders in general, whatever may be the application or model, alternating or
rotating
In the exploders as heretofore constructed the armature is massive and is fixed
upon a square of oft iron, clamping the extremities of the plates of the magnet with
or without a space between them In other more recent arrangements superior to
those with a massive polar armature, the said armature is constructed as follows, that
1s to say, the plates of the magnet are separated, and four plates of soft iron form an
armature upon which is arranged the bobbin These plates of soft iron interspersed
between the plates of the magnet do not constitute a homogeneous mass.
There is
consequently an obstacle in the armature to the distribution of the magnatism of the
magnet. This arrangement gives interior results to those obtained when the armature
is a massive one, but they are much inferior to those obtained with the homogeneous
lamination as hereinafter described Besides the mass the end of the armature
engaging with the magnet is not symmetrical to that of the said armature and does
not afford a perfect continuity or evenness of section
"6
The lamination of thin plutes of soft iron constituting my armature are applied to
the polar extremities of a magnet of a magneto-electric fuse or exploder such as is
commonly known as a coup de poing."' The magnets of steel separated by the
laminated armature of soft iron of which one extremity is in the shape of a bobbin
limited by cheeks or flanges of fibre, and covered with well insulated fine wire.
A screw is moreover provided to fasten the magnets to the armature.
The plates of iron constituting the laminated armature of soft iron are united
together and are parallel and continuous in their whole length, without stop or

page_text: contraction, thus insuring a good set and a rapid distribution of magnetism, as well
for the rapid magnetizing as for the demagnetizing of the polar extremities provided
with these special armatures. These plates are of a similar thickness, so that if there
are 9 plates of soft iron between the top and middle part of the magnet and nine
plates between the middle and bottom parts of the said magnet there should be 18 at
the opposite extremity of the armature and the thickness of the 9 plates plus 9 plates
equals the thickness of the 18 at the opposite end The cheeks or flanges also serve
to preserve and retain the said plates in position
The number of plates composing the magnet that is employed is immaterial the
thin plates of soft iron are so arranged in any case that they are parallel and con-
tinuous and conveniently set in their entire length
In a modification of my improved apparatus the thin plates of soft iron are
constructed in the form of forks and are united together in a parallel direction in
their entire length, without stop or contraction thus insuring a rapid distribution of
magnetism in the whole mass of the armature a necessary condition to obtain a rapid
magnetizing and de-magnetizing of this polar armature, and consequently a maximum
power superior to that obtained with any of the armatures already known.
The forks united as I have just described may be in two pieces, the lamination,
parallel continuous and homogeneous throughout the entire length
The form of this laminated armature composed of forks depends upon the number
of the steel plates composing the magnet. The magnet itselt can be covered according
to the "Jamın " process. This arrangement is also applicable to the magnets herein-
before described.
In an armature constructed according to my arrangement of lamination with thin
parallel plates of iron, forming a whole, homogeneous and continuous in the entire
length of the armature, the whole available magnetism of the magnet passes rapidly
and without obstacle to the extremities of the said laminated armature, thus giving a
superior result to that obtained from any other arrangements in use up to the present
time.
HASELTINE, LAKE & Co,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.

page_text: Figure 4 is a side view, ади
Figure 5 is an end view of a modification of the device.
Figure 6 an upper view of the same part being broken away at A' to show the
interior strips or sheets.
Figures 7, 8 and 9 are respectively a side view, an end view, and an upper view
showing one of the arrangements heretofore used.
In the exploders as heretofore constructed, the armature F is solid and is fixed upon
a square piece of soft iron receiving the extremities of the plates of the magnet, with
or without a space between them In other more recent arrangements the said
arinature F is constructed as shown in Figures 7, 8 and 9. The plates A of the
magnet are separated as done by Siemens and four plates of soft iron 1, 2, 3, 4, form
an armature upon which are arranged the cheeks or flanges ¹. These plates of soft
iron placed between the plates of the magnet do not constitute a homogeneous mass
from a to b. There is consequently an obstacle to the distribution in F of the
magnetism of the magnet This arrangement gives much inferior results to those
obtained with the homogeneous strips or sheets as shown in the figures above
mentioned. Besides the mass at fand f' is not symmetrical to that of F and does not
afford a perfect continuity or evenness of section, as in Figures 1 to 6.
Figures 1, 2 and 3 of the drawing show by way of example the arrangement of the
thin strips or sheets of soft iron which constitute my improved armature, and the
application of the same to the polar extremities of a magnet of a magneto electric fuse
or exploder. A' A" A"" are magnets of steel separated by the laminated armature
of soft iron F one extremity of which forms with the cheeks made of fibre a bobbin
which is covered with well insulated fine wire. V is a screw provided to connect the
magnets to the armature Figures 1, 2 and 3.
The strips or sheets of soft iron constituting the laminated armature of soft iron
are united together and are parallel and continuous in their whole length from a to b

page_text: without a stop or contraction, thus ensuring a rapid distribution of magnetism for the
rapid magnetizing and for demagnetizing of the polar extremities provided with these
improved armatures. The aforesaid strips or sheets are of the same thickness so that,
if there are nine strips or sheets of soft iron at f and nine strips or sheets at fi there
will have to be eighteen at F, and the thickness off plus fequals F. The cheeks or
flanges also retain the said strips or sheets in position
The number of plates of the magnet employed can be varied and the thin strips or
sheets of soft iron are so arranged that they are parallel and continuous in their entire
length from a to b.
Figures 4, and 6 show a modification of the improved apparatus in which the thin
strips or sheets of soft iron are in the form of forks cut out F F F ff and are united
together in a parallel direction in their entire length a b without a stop or contraction,
thus ensuring a rapid distribution of magnetism in the whole mass of the armature F,
a necessary condition to obtain a rapid magnetizing and demagnetizing of this polar
armature, and consequently a maximum power superior to that obtained previously
with any of the armatures already known.
The forks united as above described may be made of two parts cut in their entire
length on the line X X of Figures 4, 5, the strips or sheets being parallel, continuous
and homogeneous from a to b
The form of this laminated armature composed of forks depends upon the number
of the steel plates composing the magnet, the magnet itself can be made of lamina on
the "Jamin" principle This arrangement is also applicable to the magnets herein-
before described with reference to Figures 1, 2, and 3.
By this improved method of arranging with thin plates of iron parallel to each
other so as to form a whole homogeneous and continuous in the entire length a b of
the armature F all the available magnetism of the magnet caused to pass rapidly
and without obstacle to the extremities of the said laminated armature, thus producing
a superior effect to that obtained by any other arrangements in use up to the present
time.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
The application to magneto-electric exploders, irrespective of their uses and the
model employed, either of the alternating or rotary kind, of armatures made of strips
or sheets of soft iron, the coils being placed upon these armatures as hereinbefore
described and represented in the accompanying drawings.
Dated this 7th day of March 1889.