Improvements in Electrical Insulators and Method of Making the the same.
Year: 1898

page_text: Date of Application, 14th Mar., 1898-Accepted, 20th May, 1898
COMPLETE SPECIFICATION.
Improvements in Electrical Insulators and Method of Making the
the same.
I, JOHN WILLIAM BOCH, of East Liverpool, County of Columbiana, State of
Ohio, in the United States of America, Manufacturer, do hereby declare the nature
of my invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
Insulators constructed in accordance with my invention are more particularly
such as are adapted for use on electric lines for the transmission of energy with
currents of high voltage. The object of my invention is to produce a strong and
effective insulator for this purpose, and one which will offer high resistance to
leakage of current through the body of the insulator. A further object of my inven-
tion is to so construct the insulator as to prevent arcing of the current from
the edges of the petticoat of the insulator during wet weather, and more particu-
larly to the metal pin which binds the insulator to the supporting arm.
In the accompanying drawings,
Fig. 1 is a sectional view illustrating one step in the manufacture of one form of
my improved insulator:
Fig. 2 is a sectional view of a finished insulator:
Fig. 3 is a sectional view of a finished insulator of modified form, and
Fig. 4 is a similar view of a further modification.
In these drawings I have shown a triple petticoat type of insulator, but my
invention may be employed in the manufacture of double petticoat insulators or
other styles. The insulator is built up of two or more separately molded parts
preferably of clay. While I prefer to use porcelain in the construction of my
insulator, earthenware, glass or other like or equivalent material may be used for
some or all of the parts in certain constructions. In making the triple petticoat
style of insulator, it is preferred to make it of three separately molded pieces of
clay.
Referring to Figs. 1 and 2, the inner part A is pressed or molded with a threaded
or other suitable socket a for the reception of the supporting post which may be of
wood, but is preferably of porcelain, earthenware or glass, as hereinafter described
with reference to Figs. 3 and 4. The outer part C, shaped like a bowl, is pro-
vided with a cross notch c on top for the reception of the electrical conductor. It
has side shoulders c¹ c', by which the conductor may be wired down. The inter-
mediate part B is made bowl-shaped, and the several parts are molded so as to
nest or fit into each other in the manner shown, preferably with corresponding
centering projections and recesses xx.
In carrying out my invention, the separately molded parts A, B, C, of clay, after
coming from the press, are first dried out separately. This is preferably done in
an oven or kiln in the usual manner of drying clay articles by the process known
as biscuit-firing. When these separate parts have thus been biscuit-fired or
otherwise dried and are ready to be put into the vitrifying kiln, they are each
coated with glazing material, preferably all over, as by dipping the article into
uch liquid glazing material. The two or more parts of each insulator thus coated

page_text: are now fitted into each other and are stood upside down, as it were, that is, with
the lower ends of the bowls uppermost, as shown in Fig. 1. Glazing material
is then put into the joints, that is, into the annular channels between the petti-
coats and this may be most conveniently done by pouring the liquid glaze into
the channels as indicated at y in the said figure.
The parts thus put together and supplied with glazing material are now put into
a sagger with the petticoats uppermost, as shown in Fig. 1, and placed in a kiln,
in which, under great heat, the clay shrinks and becomes vitrified, as usual, and
the glazing material melts and becomes of a glass-like character. That glaze
which was put into the annular channels between the petticoats, flows
down into and fills all the spaces between the parts of the insulator,
such spaces either being there by lack of correct fit of the parts or arising during
the shrinkage by the vitrification of the clay. The result is that the two or more
separately molded parts are firmly united to each other throughout, by means of
the glass-like glaze.
Owing to the supply of the extra glazing material between the petticoats or at
the joints, I prevent the formation of air spaces or cracks for the entrance of
moisture in the finished insulator and which are almost certain to occur in the
absence of such provision of additional glazing material. A solid and practically
impenetrable layer or layers of glaze will thus be formed between the conductor
and the supporting pin.
I
In order the more effectually to prevent arcing of the high potential current
from the edges of the petticoats of the insulator during wet weather, and more
particularly to the metal pin which binds the insulator to the supporting arm,
imount the petticoat body of the insulator upon an insulated post of porcelain,
earthenware, glass or equivalent material, preferably porcelain, and in such a
manner that it passes down through an opening in the wooden cross arm or sup-
port, the metal fastening pin being secured in the post.
In the construction shown in Fig. 3, the tubular supporting post P is made in
one with the central part of the body of the insulator. This post P may, how-
ever, be made separate from the body parts as illustrated in Fig. 4, where the
central body part A is shown as having a central opening a (screw-threaded in
this instance) for the insertion of the upper end of the supporting post P₁. This
supporting post and central part may be secured together by any suitable means,
as by glaze, in the course of manufacture, if the parts are to be all of porcelain,
as above described. The post may be made out of two molded tubes p p of glaze,
one fitted within the other, and secured together by an intervening tubular layer
of glaze, as indicated at g, in Fig. 3.
In any construction, it is important that the supporting post P or P¹ shall be
at its lower end adapted to enter an opening made in the wooden or other cross
arm, shown by dotted lines, and that in annular shoulders be formed on the
post to rest on the cross-arm and form a point of support.
The vertical opening in the support P or P is of a diameter suitable to receive
the iron or other metal securing pin R, which is indicated by dotted lines, and
which extends up into the post to any desired height and is secured by a suit-
able cementing composition. A nut n and a washer u, indicated by dotted lines,
complete the means for securing the whole in place on the cross-arm. In Fig. 3,
the securing pin is shown as having a polygonal head, while in Fig. 4, the pin is
shown as notched to get a hold in the cement.
In the described construction, it will be seen that the pin R is so well pro-
tected by the tubular post, which sheaths it, and passes down through the cross-
arm 1), that leakage of current or arcing across from the edges of the petticoat to
the pin (liable to occur on high potential circuits of present construction) is here
obviated. The exposed end of the pin and its nut and washer on the underside
of the cross-arm, are too far away from the conductor in the notch c to give
trouble

page_text: 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. As a new article of manufacture, a porcelain or earthenware insulator made
of two or more parts of clay fitted one within the other with extra glaze intro-
duced to fill all the spaces where the parts are to be united and form a solid layer
of glaze between the conductor and pin, substantially as herein before described.
2. A high potential petticoat insulator having a vertical tubular post of porce-
lain or equivalent material, secured to and supporting the petticoats of the insu-
lator, and having its lower end adapted to fit into an opening in the cross-arm,
and a metal fastening pin in the said tubular post, substantially as hereinbefore
described.
3. A high potential insulator having a supporting post made in one with a
part of the body of the insulator, the said supporting post having its lower end
adapted to fit into an opening in the cross-arm, with a fastening pin secured in
the post, substantially as hereinbefore described.
4. A high potential porcelain insulator formed of parts united together and
comprising a body with one or more petticoats and a porcelain supporting post
all united together, the supporting post having its lower end adapted to fit into
an opening in the cross-arm to receive a securing pin from the underside, sub-
stantially as hereinbefore described.
5. A high potential porcelain insulator formed of parts united by intermediate
layers of glaze, and comprising a body part with a petticoat or with more than one
petticoat and a supporting post whose lower end is adapted to fit into an opening
in the cross-arm to receive a securing pin from the underside, substantially as
hereinbefore described.
6. A high potential porcelain insulator having a supporting post made of two
tubes, one fitted within the other with an intermediate tubular layer of glaze,
substantially as hereinbefore described.
7. The mode herein described of making a petticoat insulator by molding it
in two or more parts of clay, coating them with glazing material, fitting them
together, supplying extra glazing material at the joints between the petticoats
and firing the united and coated parts with the petticoats uppermost, so that the
glazing material will be melted and flow into and fill all the spaces between the
parts, substantially as hereinbefore described.
8. The mode herein described of making a petticoat insulator, by molding it in
two or more parts of clay, fitting them together, supplying glazing material at
the joints between the petticoats, and then firing with the petticoats uppermost,
whereby the clay will become vitrified, and at the same operation the glazing
material will be melted and flow into and fill the spaces between the parts, sub-
stantially as herein before described.
9. The mode herein described of making a petticoat insulator, by molding it in
two or more parts of clay, biscuit-firing the parts separately, fitting them
together, supplying glazing material at the joints between the petticoats, and
firing, with the petticoats uppermost, so that the glazing material will be melted
and How into and fill all the spaces between the parts, substantially as herein-
before described.
1
1. 1000