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To all whom it may concern: Be
it known that I, RALPH D. MERSHON,
a citizen of the United States, residing in Colorado Springs, in the
county of El Paso and State of Colorado, have invented a new and useful
improvement in insulators, of which the following is a specification. My
invention relates to insulators for electric line conductors; and it has
for its object to provide a device of this general character which shall
be particularly adapted for use in connection with high-tension circuits
and be at the same time simple and inexpensive in construction. Considerable
difficulty has been heretofore experienced in connection with the
overhead transmission of electrical energy over great distances for
power and other purposes by reason of the failure to prevent the current
from jumping over their surface or through the air to the
supporting-pins or cross-arms and thence to the ground and also by
reason of the leakage over the surface of the insulators, It is
obviously desirable to employ insulators for this class of work which
shall afford the greatest striking distance between the conductor and
the support for the insulator proper that is consistent with simplicity
and with economy in construction and which shall also embody a
construction that affords a maximum length and a minimum width of
surface between the conductor and the supporting-pin in order to reduce
the danger of leakage as much as possible.
The insulator that I have devised for this purpose is illustrated
in the accompanying drawings, in which-- Figure
1 is a view, partially in side elevation and partially in section, of
the insulator proper, the supporting-pin, and a portion of the
cross-arm. Fig. 2 is a plan view of the parts shown in Fig. 1. Referring
now to the details of construction illustrated in the drawings, 1 is the
cross-arm, and 2 the supporting-pin, the upper end of which is
preferably screw-threaded to engage with a corresponding screw-threaded
recess in the insulator 3. The general form of the upper portion of the insulator 3 is not materially different from those heretofore used, except that it is provided with ridges 4 for conducting water away from the portions located directly above the cross-arm. The invention is not limited as regards the number or shape of these ridges. There should, however, be at least two, one at each side, and each of them should preferably extend downward and inward from a point substantially over the middle of the cross-arm to a point beyond the edge of the cross-arm. It will be understood, moreover, that grooves may be employed in lieu of ridges for conducting the water away from the cross-arm, if found feasible or desirable in practice. I provide the under side of the insulator with an inner long petticoat 5, that is substantially tubular, the inner side being adjacent to the pin 2 and separated therefrom by a |
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comparatively
small space. The lower edge
of this petticoat 5 is located a comparatively short distance above the
cross-arm 1. The edge 6 of
the insulator has a materially greater diameter than the petticoat 5 and
is located sufficiently above the edge of the latter so that the
striking distance between the former and the cross-arm is approximately
equal to that between it and the supporting-pin 2. The
petticoat 6 also protects to a greater or less extent the petticoat 5
from rainfall. I
have shown the insulator as provided with an intermediate petticoat 7 in
order to guard against any possible creeping of the moisture onto the
inner petticoat 5; but this part 7 is not essential to the invention.
In fact, I desire it to be understood that the invention is not
limited as regards the number of petticoats employed beyond the two
first described. It will be understood further, that the invention is useful
and operative without the water-conducting ridges 4; but these features
are considered as desirable and will preferably be employed in practice. It will be readily seen that by employing the long inner petticoat 5 in
connection with the short outer petticoat 6 a comparatively small, and
consequently strong and easily manufactured, insulator is provided which
ensures the requisite striking distance between the wire or the edge of
the petticoat 6, Should
the latter be wet, and the pin and cross-arm.
Furthermore, since the petticoat 5 is both long and narrow it
fulfils the conditions required for insuring a minimum amount of surface
leakage. I
claim as my invention-- 1.
An insulator for high-tension circuits having a long, tubular petticoat
adjacent to the supporting-pin and a short outer petticoat of much
greater diameter the edge of which is approximately the same striking
distance from the cross-arm and the supporting-pin. 2.
An insulator for high-tension circuits having two or more ridges on its
outer surface which extend transversely to the cross-arm, a long,
tubular petticoat adjacent to the supporting-pin and an outer petticoat
of much greater diameter the edge of which is approximately the same
striking distance from the supporting-pin and the cross-arm. 3.
An insulator for high-tension circuits having outer ridges transverse to
the cross-arm, a long tubular petticoat adjacent to the supporting-pin
and a plurality of short petticoats, the outer one of which has a much
greater diameter than the long petticoat and is approximately the same
striking distance from the supporting-pin and the cross-arm. In
testimony whereof I have hereunto subscribed my name this 11th day of
February A.D. 1898.
RALPH D. MERSHON. Witnesses: WESLEY
G. CARR, H. C. TENER.
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