Electric Soldering-irons.
Year: 1890

page_text: Complete Specification Lett, 20th Nov., 1090-Accepted, orst vall,
COMPLETE SPECIFICATION.
Electric Soldering-irons.
I, CHARLES EDWIN CARPENTER, of No. 61 Highland Avenue, in the City of
Minneapolis, County of Hennepin, State of Minnesota, United States of America,
Electrician, 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 :-
This invention relates to improvements in electric soldering irons. The class of
irons to which the present improvements are particularly applicable is that in which
heretofore the resistance or electrical conductor has been wound or disposed about
a cylinder or body of copper, provided with a tapering head, to which the heat
generated in the resistance is conducted through the medium of the body, the
resistance or body being covered with some heat-insulating material, leaving only
a tapering head or point of the iron exposed.
It is obvious and well understood that with the cylindrical soldering iron, there
is considerable waste of energy or current, because of the great radiating or heating
surface of the body, which must first be heated to a high degree, before the head
or point of the iron, which can alone be utilized in practice, is heated to a sufficient
degree. Besides which, practice has demonstrated that the space is too small to
provide sufficient heat insulation between the outside covering or casing and the
body or cylinder portion of the iron, and hence the casing will be heated to a
temperature sufficiently high to be not only extremely objectionable, but wasteful
of much of the energy supplied to the iron.
The prime object of the improvements is to heat and confine the heat only to that
portion of the iron which is employed in practice, viz. the head or point thereof,
whereby the compactness, simplicity, and effectiveness of the iron are increased, and
the iron is rendered easier of manipulation and more economical in use.
Another object of these improvements is to dispense with the cylindrical body
portion of the iron and the accompanying heat insulation.
Another object of the improvements is to so connect the handle to the heated
portion of the iron, as to avoid the objectionable heating of the same.
A further object is to have the iron of such construction that any desired degree
of pressure may be employed in binding the elements together, whereby the effect
of the heat evolved from the resistance or electrical conductor will be greatly
intensified, and the elements at the same time held in fixed relation to each other
against shifting, induced by jarring or otherwise.
These objects are attained by the devices illustrated in the accompanying
drawings, in which―
Fig. 1 represents a central longitudinal section through a soldering iron embodying
my invention;
Fig. 2 a transverse vertical section on the line 2, 2 of Fig. 13
Fig. 3 a detail longitudinal section through the iron, showing a modified
construction thereof;
Fig. 4 a detail side elevation of a modified form of core;
In these figures A. indicates a core having the contour of a frustum of a cone, the

page_text: conical surface of which is covered with a layer of electrical insulating material B
of uniform thickness, and of a character that will endure high temperature and is a
fair conductor of heat, such as asbestos paper, upon which is tightly wound, in an
open spiral coil, the resistance or electrical conductor C, consisting preferably of a
fine metallic wire of highly refractory character, beginning at one end of the cone,
and terminating at the other, the terminal D near the apex of the cone preferably
being insulated, and brought back through a hole or passage in the core, and then
united with one of the line wires E, lying in the central passage through the handle
of the iron, the other line wire Falso leading through the handle, and being
connected with the opposite terminal of the resistance at or near the base of
the conc.
The outer shell or body G, consisting preferably of copper, and having a conical
exterior surface similar in shape to that of an ordinary soldering iron, is employed
for receiving the core and the electrical resistance wound thereon, to which end it
is provided with a tapering cavity corresponding to the taper of the core A, which
cavity is first lined with a layer of an electrical insulating material H, similar to
that already described for the core, after which the core, with its covering of
insulation and resistance wire, is inserted in position in the cavity, and forced firmly
against the walls thereof by means of a screw 1, passing axially through the core,
and entering a screw threaded socket in the tip of the shell or body of the iron,
thereby firmly binding the elements together under any desired pressure, and
securing them in position against displacement, due to jarring or blows upon the
iron in its practical use, or to the possible shrinkage of the electrical insulations
between the resistance and the body and core of the iron, as a result of the great
heat to which they are subjected.
This iron, as a whole, is secured to a handle J of any suitable form or material,
for convenience of manipulation, by means of a tube K, having a screw thread
connection at one end with the ferrule L of the handle, and at its opposite end with
a cap M secured to the core of the iron by means of the screws N, between which
cap and the iron proper is inserted a layer of asbestos or some other heat-insulating
material O, for preventing, to the greatest possible degree, the conduction of the
heat from the iron to the handle, the cap being preferably recessed on the inner
face thereof, so as to provide an air space for promoting the heat insulation, and at
the same time furnish a passage for the disposal of the resistance wires.
From the foregoing description, it will be readily seen that the heat evolved from
the resistance or electrical conductor, is utilized to the maximum degree, for there
is no cylindrical body portion to which the heat is first imparted, as has heretofore
been the case, but only the part of the iron which it is practically desired to heat,
that is, the head or point thereof, will now be heated, and by the employment of the
core, the point or head of the iron is rendered practically solid, and will retain in
the maximum degree the heat imparted thereto, and which has heretofore been
dissipated through the heat insulations and casing of the iron body.
If desired to ensure the retention of the resistance in fixed relation to the core,
the whole may be provided in the conical surface thereof with a spiral groove, as
illustrated in Figs. 3 and 4, into which the wire and electrical insulation will be
sunk, and the convolutions of the wire thus retained in position against slipping
upon the cone; this groove, while not absolutely essential to the successful operation
of my invention, at the same time being an advantageous feature of construction.
Other changes and modifications than those which I have before suggested in the
construction and arrangement of parts, may be made without departing from my
invention, and such changes and modifications are intended to be included within
the present invention.
Having now particularly described & 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 :-
1. In an electric soldering iron, the combination, with a hollow body and the

page_text: tapering core fitting within said body, of the resistance disposed about the core, and
electrical insulations interposed between said resistance and the core and body,
substantially as described.
2. In an electric soldering iron, the combination, with the hollow body and the
tapering core fitting within said body, of the resistance disposed about the said core,
and electrical insulations interposed between said resistance and the core & body,
and means for binding said elements together under pressure, substantially as
described.
3. In an electric soldering iron, the combination with the hollow body, the
tapering core fitting within said body, the resistance disposed about said core,
electrical insulations interposed between said resistance and the core and the body,
and means for binding said parts together, of the handle attached to said core, and
the heat insulation interposed between said handle and the core and body, sub-
stantially as described.
4. In an electric soldering iron, the combination with the hollow conical body,
and the tapering core fitting within said body, of the resistance disposed about said
core electrical insulations interposed between said resistance and the core and
body, and a screw passing axially through the core and engaging the body, so as to
bind the said members firmly together under pressure, substantially as described.
5. In an electric soldering iron, the combination with the hollow body, of a
tapering core having a spiral groove in the conical surface thereof, and fitting
within said body, of the resistance and electrical insulations interposed between
said resistance and the core and the body, substantially as described.
Dated this 26th day of November 1890.
NEWTON & SON,
Agents for the Applicant.

page_text: Dong καισ
United States of America),
Date of Application (in United Kingdom), 26th Nov., 1890
Complete Specification Left. 26th Nov., 1890-Accepted, 14th Mar., 1891
COMPLETE SPECIFICATION.
Improvements in Electric Soldering Irons.
1, CHARLES EDWIN CARPENTER, of No. 61, Highland Avenue, in the City of
Minneapolis, County of Hennepin, State of Minnesota, United States of America,
Electrician, 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 :-
This invention relates to improvements in that class of soldering irons com-
monly known as "hatchet irons," principally employed in the making of cans
and analogous uses. These irons have the general shape of an ordinary hatchet,
and derive their heat from an external source, generally by being inserted directly
into the fire.
The prime object of this invention is to have such an iron electrically heated,
and of such construction that the wearing parts thereof may be readily replaced by
new parts.
Another object is to have the electro-heating elements of the iron so disposed
that the electrical conductor or resistance may at all times be maintained under
sufficient pressure to promote the desirable results from its use to the maximum
degree.
These objects are attained by the devices illustrated in the accompanying drawing,
in which
Fig. 1 represents a side elevation of a soldering iron embodying my invention,
with parts broken away the more clearly to disclose the internal structure
thereof.
Fig. 2 a top plan view thereof, shown partly in horizontal section on the line 2. 2
of Fig. 1, and
Fig. 3 a transverse vertical section on the line 3. 3 of Fig. 1.
Similar letters of reference indicate the same parts in the several figures of the
drawing.
Referring by letter to the accompanying drawing, A indicates the main body of
the iron, preferably composed of a block of copper of suitable dimensions and con-
figuration on each side of which is located a cheek or compressing plate B, preferably
composed of iron, between each of which and the body is interposed a resistance or
electrical conductor C separated from both the body and the cheeks by layers of
electrical insulating material D E, preferably in the form of thin sheets of asbestos
paper to one of which the resistance, in the form of a fine iron wire, may be
suitably secured. This electrical insulation, however, should be of such character
as to oppose the minimum obstruction to the passage of heat from the resistance to
the body of the iron. The inner insulation D is interposed between the resistance
and body of the iron, solely for the purpose of preventing electrical contact there-
between, and the resultant short-circuiting of the resistance, and other evils which
would necessarily attend such contact; but the insulation E between the cheeks

page_text: either the conduction or radiation of the heat evolved from the resistance, -and
should therefore be of such thickness and character as to accomplish this
desirable end.
The cheeks are secured in position upon the body by means of screws F
working freely through one of them and the body, and engaging screw-threaded
perforations or sockets in the other cheek, thus furnishing at the same time a
means for binding the checks and the intervening elements against the iron body
under pressure, which may be varied at will, and which at all times will be
sufficient to prevent short-circuiting of the resistance or electrical conductor, and
the resultant fusion thereof, or the falling away of the same from the insulation, to
which it is secured or between which it is confined.
The body portion of the iron extends slightly below the cheeks, and is provided
with a removable blade G, fitting onto the body, and having a groove of any
suitable character fitting closely upon a ridge of corresponding form on the body A,
extending from end to end thereof. This ridge and groove connection subserves
the double purpose of providing a large surface for contact between the body
and the blade, and of preventing a lateral movement of the blade with relation to
the body.
The resistance employed is preferably of the reflex type, as illustrated in Fig. 1,
and composed of iron wires disposed upon the card of asbestos board in any suitable
manner.
For convenience in manipulating the iron, I provide a cap H, secured to one end
of the body by screws I, into which cap is screwed one end of a tube J, which acts
as a handle, and also provides a channel for the inleading wires K K to the
resistance, the tube at its opposite end having fastened thereon a ferrule L to
receive the handle proper M of the tool.
For the better insulation of the handle from the heat of the iron body, a
packing of asbestos N, or other suitable material, is interposed between the cap and
the body.
From the foregoing it will be readily understood, that while in this iron are
contained features common to other irons heretofore patented by me, at the same
time it contains structural differences, possessing many advantages in the uses to
which my invention is to be put.
For instance, the body, which is composed of a flat block of copper or other
suitable metal, has a heating resistance lying on each side thereof, and confined
thereon in such manner that the heat evolved from the resistances will be confined
directly to the body, and from it transmitted by conduction to the removable blade,
which being a part subjected to constant wear, may by reason of its construction,
be readily replaced by a new blade when worn beyond usefulness.
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 :-
1. In an electric soldering iron, the combination with the body and the cheek
plates thereof, of an electrical conductor or resistance interposed between each of
said plates and the body, and an insulation interposed between said resistances and
the body and the plates, substantially as described.
2. In an electric soldering iron, the combination with the body, the cheek plates
on each side thereof, and a removable blade attached to said body, of an electrical
conductor or resistance interposed between each of said plates and the body, and
an insulation interposed between each of said resistances and the body and plates,
substantially as described.
3. In an electric soldering iron, the combination with the body, the cheek plates
on each side thereof, and means for binding said plates to the body under pressure,
of an electrical conductor or resistance interposed between each of said plates and
the body, and an insulation interposed between each of said resistances and the body
and plates, substantially as described.

page_text: 4. In an electric soldering iron, the combination with the body, the cheek plates
on each side thereof, means for securing said plates to the body under pressure,
and a removable blade attached to the body, of an electrical conductor or
resistance interposed between each of said plates and the body, and an insulation
interposed between said resistances and the body and plates, substantially as
described.
5. In an electric soldering iron, the combination with the body, the cheek plates,
screws securing said plates to the body, a removable blade provided with a longi-
tudinal groove fitting upon a ridge on the body, and a screw passing through the
body and securing the blade in position, of an electrical conductor or resistance
interposed between each of said plates & the body, and an insulation interposed
between said resistances and the body and plates, substantially as described.
Dated this 22nd day of December 1890.
NEWTON & SON,
Agents for the Applicant.