Improvements in Electric Insulators.
Year: 1899

page_text: Date of Application, 13th Feb., 1899-Accepted, 25th Mar., 1899
COMPLETE SPECIFICATION.
Improvements in Electric Insulators.
I, FREDERICK HENRY WITHYCOMBE, of No. 20, Park Avenue, in the City of
Montreal, in the District of Montreal, and Province of Quebec, Dominion of
Canada, Lecturer, 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:-
-
It is well known that the glass and other insulators used on telegraph and other
electric lines are frequently made the targets of, and are broken or damaged by
stones and other missiles. The damage resulting partially or wholly destroys
their usefulness and necessitates the trouble and expense of replacing them,
besides causing inconvenience by the interruption of communication.
My invention relates to the special formation of the exposed surfaces of insula-
tors and extensions therefrom apart from the general design or material employed.
My invention has for its object to render insulators of whatever form less
liable to breakage, by providing a simple and efficient means to enable them the
better to withstand the impact of foreign bodies.
The invention consists generally in replacing the smooth outer surfaces of
insulators as now made of glass, porcelain or other insulating material, by an
outer surface construction of small protuberances, ridges or depressions. These
small protuberances, ridges or intervening portions between the depressions, which
may be of any desired section, form an exterior construction which will break
down rapidly with the impact of missiles. This breaking down of the intercepting
parts, cushions the blow and relieves the main portion or body of the insulator
or extension therefrom, it is desired to protect, from the full severity of the
impact. It will thus be seen that the small intercepting parts, with which the
missile first comes into contact, offering a sufficiently less resistance than that
portion of the main body, or extension therefrom it is intended to protect, will
crush or crumble under the force of impact and thus cushion the blow by using
up a large proportion of the energy. My experiments have proved this to be the
case.
Insulators having one or more petticoats, whether extending horizontally,
vertically or obliquely, of proportions which render them very easy of breakage
by missiles, can thus be made to offer greater resistance to fracture by forming
the exposed surfaces, both of the main body and extensions therefrom, in the
way and as herein described.
For full comprehension, however, of the invention, reference must be had to
the annexed drawings forming a part of this specification in which like symbols
indicate corresponding parts and wherein Figure 1 is an elevation half in section
illustrating an insulator provided with my protective cushion surface in the form
of horizontal ridges of very small cross section.
Figure 2 is a similar view of an insulator having a modified form of protective
surface in the form of oblique ridges of very small cross section.
Figure 3 a similar view of a third insulator provided with a protective
surface of vertical ridges of very small cross section.

page_text: Figure 4 a similar view of a fourth insulator provided with a protective surface
in the form of a spiral ridge or ridges also of very small cross section.
Figure 5 is a similar view of a fifth insulator the protective surface of which
is composed of small protuberances, and
Figure 6 a similar view of a sixth insulator, in which the protective surface
is made up by the intervening portions between depressions in the insulator
body.
The insulators shown are of the same general form as those now in use, having
a central cylindrical part 1, surmounted by a dome shaped upper portion or
crown 2, and having depending from it the petticoat 3. The interior is provided
with the usual threads 4 adapted to screw on the end of the supporting pin, peg
or stick. The usual groove 5 is provided for attaching the wire.
The insulator shown in Figure 1 is provided with horizontal ridges or projec-
tions (6) and depressions (7) encircling the exposed surfaces of the insulator,
the projections being of such small cross section as to allow of a large number
being formed so as to effectively protect every portion of the exposed surface of
the insulator and at the same time be easily broken or crushed by the impact of
a stone or missile. To provide for the flow of moisture from the insulator, vertical
or oblique channels are provided at intervals.
The modified form of insulator shown in Figure 2 is provided with oblique
ridges 8 of small cross section (so as to be easily broken or crushed by impact of
a stone or missile) and depressions, grooves or channels 9 more or less encircling
the exposed surfaces of the insulator so that moisture will run from top to
bottom and not lodge at any point.
Another modified construction is shown in Figure 3, as formed with vertical
fragile ridges 10 of small cross section and depressions, grooves or channels 11
extending from top to bottom of the exposed surfaces of the insulator so that
the flow of moisture from top to bottom will be greatly facilitated, and any
missiles striking the insulator, crush one or more of such ridges and then glance
off, leaving the main body unhurt.
A third modification shown in Figure 4 of the drawings is formed with a spiral
ridge 12 of small cross section and therefore readily frangible, encircling the
exposed surfaces of the insulator so that while affording both a channel for
moisture and a protection against any serious damage from missiles, it will also
tend to deflect or guide a crack, should such occur, in a circumferential instead
of vertical direction thus ensuring a longer life for the insulator.
A further modification shown in Figure 5 of the drawings is formed with small
and therefore readily broken protuberances 13 which may be of any desired form
(rectangular, conical, pyramidal, cylindrical, or otherwise) and preferably
arranged in oblique lines as on the dome of the insulator, or in horizontal lines
as upon the petticoat thereof so that the flow of moisture will in no way be impeded
and yet every part of the exposed surface fully protected by the cushion-like
protuberances.
Still another modification is shown in Figure 6, when the surface is formed with
small depressions 14 which may be of any desired shape such as conoidal, trian-
gular, pyramidal or otherwise. The portions intervening between the depressions
forming an intercepting and protective cushion on the exposed surfaces of the
insulator and extension therefrom, of small and easily broken portions 15 between
the depressions.
The chief function of the surface formation in each case (made up as it is of a
large number of ridges or protuberances, or intervening portions between
depressions, of small cross section) is, that when a missile strikes the insulator it
will come in contact first with such protecting or intercepting parts of the surface
which being of a fragile or easily broken and yielding formation will give way
to the impact of the foreign body.
The energy of the impact being largely expended in crushing these parts, the
result will be to cushion the blow and reduce its severity as regards the main

page_text: body of the insulator, or extensions therefrom and unless the impact be very severe
and violent the insulator will be saved from fracture.
It will be apparent that unlimited modifications can thus be made without
departing from the scope of my invention. For instance, a surface conformation
of small projecting knobs of one or more different forms, and ridges of one or more
different forms, may be arranged in one or more different ways on the surfaces of
the same insulator to form the protecting medium.
Again, grooves and depressions of one or more different forms may be arranged
in unlimited ways so that the intervening ribs or portions between such depressions
or grooves, may be of any one or more different forms or sections, which inter-
vening portions between the grooves or depressions from the protecting medium, or
the cushion surface may be composed of particles of the same material embedded
in or attached to the main body of the insulator while in a soft or molten condition
during manufacture.
Therefore I do not limit myself to any particular form or arrangement of the
small and easily broken portions with which the missile first comes in contact,
as my invention is broadly to construct or form those surfaces of insulators or
extensions therefrom which are liable to be struck by missiles, into small and
therefore easily broken sections to receive the first shock of a blow.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1. An insulator the entire outer or exposed surface of which is in the form of
a protective cushion or guard made up of small projecting portions or ridges or
intervening portions between depressions of small cross section so as to be
structually more fragile than the main body, or any extension therefrom, on which
they project in uniform depth and proximity, and having downward leading
channels for the flow of moisture, substantially as shown and described.
2. An insulator the entire outer or exposed surface of which is in the form
of a protective cushion or guard made up of small and easily broken horizontal
ridges and having water channels, substantially as shown and described.
3. An insulator the entire outer or exposed surface of which is in the form of a
protective cushion or guard made up of small and easily broken ridges running
in an oblique direction and having water channels substantially as shown and
described.
4. An insulator the entire outer or exposed surface of which is in the form
of a protective cushion or guard made up of small and easily broken ridges
running vertically of the insulator and having water channels, substantially as
shown and described.
5. An insulator the entire outer or exposed surface of which is in the form of
a protective cushion or guard composed of a small and easily broken spiral ridge
or ridges and having water channels substantially as shown and described.
6. An insulator the entire outer or exposed surface of which is in the form of
a protective cushion or guard made up of small and easily broken protuberances
and having water channels substantially as shown and described.
7. An insulator the entire outer or exposed surface of which is in the form of a
protective cushion or guard composed of small and easily broken protuberances
arranged in oblique lines and having water channels substantially as shown and
described.
8. An insulator the entire outer or exposed surface of which is in the form of a
protective cushion or guard composed of small and easily broken protuberances
arranged in a spiral and having water channels substantially as shown and
described.
9. An insulator the entire outer or exposed surface of which is in the form of
a protective cushion or guard, the dome of which is composed of small and
easily broken protuberances arranged in oblique lines, and the exposed surface of

page_text: the petticoat of which is composed of similar protuberances arranged in a spiral
and having water channels substantially as shown and described.
10. An insulator the surface of which is divided up into small depressions, and
intervening portions between the depressions being adapted to form a protective
cushion, substantially as and for the
purpose set forth.
11. An insulator the surface of which is divided up into small depressions 14
and intervening rib portions 15 arranged in oblique cross-hatch lines and the
intervening rib portions adapted to form a protective cushion for the purpose set
forth.
בד
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1011
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1900
CARPMAEL & Co.,
Agents for the Applicant.