Improvements in or relating to Induction Coils.
Year: 1899

page_text: Date of Application, 9th Feb., 1899-Accepted, 6th May, 1899
COMPLETE SPECIFICATION.
Improvements in or relating to Induction Coils.
I, MANES EPHRAIM FULD, of 409, North Paca Street, in the City of Baltimore,
State of Maryland, United States of America, a citizen of the United States,
and General Manager of the Chloride of Silver Dry Cell Battery Company, of
Baltimore, Maryland, 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 :-
-
My invention relates to improvements in induction coils, and more especially
to that class of induction coils known as "medical coils," and the object of my
invention is to greatly increase the efficiency of induction coils by a construction
which is both simple and comparatively inexpensive.
By my said invention, I am, moreover, enabled to greatly increase the effect
or induced current of a given induction coil without materially increasing its size.
This is particularly advantageous with respect to medical coils, where it is
desirable to make the apparatus as small as possible consistent with efficiency in
order that the apparatus may be the more readily transported.
I accomplish this object by inserting between the core of the coil and the
primary and secondary coils, sheet metal which is a good conductor of magnetic
lines of force.
An induction coil thus constructed will give an induced current several times
as great as a like coil of the same dimensions without my improvement.
To more fully describe my said invention, reference will be had to the accom-
panying drawings, in which similar parts are represented by similar letters
throughout the several views.
Fig. represents a transverse vertical section of my improved induction coil
taken along the line 1-1-Fig. 2, and looking in the direction of the arrow.
Fig. 2 represents a central longitudinal sectional view of the same, taken
along the line 2-2, Fig. 2, and,
Fig. is a fragmentary perspective view, partly in section of the bobbin tube,
showing how the iron ribbon and insulation are wound thereon.
Fig. 4 represents a central longitudinal sectional view of another form of
induction coil, embodying the principle of my invention.
Fig. 5 represents in side elevation the core, iron wrapping and metal sheath of
the coil shown in Fig. 4, and
Fig. 6 represents a cross-section of the same taken along the line 6-6, Fig. 5.
In the accompanying drawings, A represents the bobbin, composed of any suit-
able insulating material, such for example as wood, vulcanized fibre, hard rubber,
paste board and the like. The tube at the bobbin may be either integral with
the bobbin ends or detachably connected to them as is sometimes done, and which
will be perfectly obvious to any one skilled in the art; but in all cases, the tube
is composed of insulating material. The bobbin is provided with the usual soft
iron core B, which, as is obvious, may be either solid, or composed of a bundle
of soft iron wires, or constructed in any other suitable way, the construction of
the core proper forming no part of my present invention. Next to the bobbin

page_text: tube is wound one or more layers of sheet iron or ferrotype ribbon, C, with
insulating material D separating each convolution of the ribbon and wound upon
the outside thereof as shown. The ribbon C may be composed of one piece or
divided into sections either in the direction of the axis of the core or at right.
angles thereto; or it may consist of a narrower ribbon than that shown, when
it may be wound on the bobbin spirally. Instead of the ribbon C, insulated iron
wire may be used. The insulation D may be paper, mica, cloth, or any desirable
insulating material or preparation.
On top of the insulation, which covers the ribbon C, are wound the primary
and secondary coils and F, respectively.
The amount of insulation between the ribbon C and the primary and secondary
coils, may, obviously be varied at will.
It is also obvious, that the method of starting and winding the ribbon C, and
the insulation D, on the bobbin, may be varied, but all the while keeping the
ribbon thoroughly insulated from the core, from the primary and secondary coils
and from itself.
But my invention is not confined alone to the form of coil above shewn and
described. In Figs. 4, 5 and 6, I have shewn a coil embodying my invention,
but differing from the form shewn in the preceding figures, principally in that
it employs a sheath regulator and does away with the necessity of wrapping the
sheet iron on the bobbin or spool proper.
According to this form of my invention the central iron core B' is inserted in a
small wooden, or other insulating material, casing A°, and around the outside of
this casing is wrapped the sheet of iron and securely glued thereto, so that
both are rigidly secured to the casing Aº.
:
The tube al of the bobbin A¹ is bored out to receive the casing A° and core B¹,
with the bore reduced as at 2, into which part one end of the casing Aº fits
tightly,
A brass or copper regulating tube or sheath & slips over the sheet iron and
core and into the bobbin tube as shown.
This sheath is the ordinary regulating sheath of medical coils, and operates
to increase or diminish the effect of the coil by sliding it out or into the coil
as is well understood. The primary and secondary coils E and F are wound
upon the bobbin core as usual. By the above described construction, the same
results are obtained as by the form of coils first described, and at the same time
obviating the necessity of winding the sheet iron on the bobbin proper, as has
been already noted.
Having thus particularly ascertained and described the nature of my said
invention, I declare that what I claim is:-
°
1. An induction coil having insulated iron wrapped upon the bobbin tube and
the primary and secondary coils wound upon the said insulated iron, sub-
stantially as herein described and shewn in the drawings hereunto annexed.
2. In an induction coil, the combination with an iron core, of a tube of
insulating material surrounding said core, insulated iron carried upon and
surrounding said tube, and the primary and secondary coils surrounding said
insulated iron, substantially as herein described and shewn in the drawings
hereunto annexed.
3. In an induction coil, the combination with an iron core, of a tube of
insulating material surrounding said core, insulated sheet iron carried upon
and surrounding said core and the primary and secondary coils wound outside
of the insulated sheet iron, substantially as herein described and shewn in the
drawings hereunto annexed.
4. In an induction coil, the combination with the bobbin, of an. iron core
carried therein, one or more layers of insulated iron carried next to the bobbin,
and the primary and secondary coils wound upon said insulated iron, sub-
stantially as herein described and shewn in the drawings hereunto annexed,

page_text: 5. In an induction coil, the combination with the bobbin, of a central iron
core carried thereby, one or more layers of insulated sheet iron wound upon the
tube of said bobbin, and the primary and secondary coils wound upon said
insulated sheet iron substantially as herein described and shewn in the drawings
hereunto annexed.
6. An induction coil having a central core, insulated iron surrounding said
core and the primary and secondary coils surrounding said insulated iron, sub-
stantially as herein described and shewn in the drawings hereunto annexed.
7. The means for strengthening the current from an induction coil, substantially
as herein described and shewn in the drawings hereunto annexed.
8. Induction coils constructed substantially as herein described and shewn in
the drawings hereunto annexed.
is th day of repruary 1999.
IS
TONGUE & BIRKBECK,
31, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.