IMPROVEMENTS IN THE INSULATING SUPPORTS OF TELEGRAPH WIRES
Year: 1877

page_text: LETTERS PATENT to John Crisp Fuller and George Fuller, both of Stratford, in
the County of Essex, for the Invention of "IMPROVEMENTS IN THE INSULATING
SUPPORTS OF TELEGRAPH WIRES."
Sealed the 6th July 1877, and dated the 8th January 1877.
PROVISIONAL SPECIFICATION left by the said John Crisp Fuller and
George Fuller at the Office of the Commissioners of Patents on the 8th January
1877.
'
JOHN CRISP FULLER and GEORGE FULLER, both of Stratford, in the County of
Essex. "IMPROVEMENTS IN THE INSULATING SUPPORTS OF TELEGRAPH WIRES.'
Hitherto it has been customary to shape the cups of telegraph insulators some-
what after the form of an umbrella or bell, with curved or parallel sides.
According to our Invention we make the insulator more or less in the form of an
inverted truncated cone. By this means we not only provide strength to that
portion of the insulator which has hitherto been found to be weak, and frequently
to burst from the expansion of the iron bolt fixture or support, but with the con-
verging sides of the cone we improve the insulation by increasing the electrical
resistance of the surface. The peculiar shape of this improved insulator renders it
less liable to the retention of any dirt or moisture on its surface, while the danger
from either external or internal fracture is considerably reduced.
We also further increase the electrical resistance when necessary by corrugating,
serrating, or under cutting the outside surface of the cone.
When we combine a separate inner cup with our improved insulator, we do not
permanently cement them together, but we make them separable. In one way we
at tightly to the inner cup a cap of vulcanized india-rubber or some other insulating
material upon which we screw or force our improved insulator, which by this means
we are enabled at any time to remove at pleasure for examination, cleaning, or
enewal without unbinding the line wire.
In the iron supports or bolts in common use it is found that the nut and screw

page_text: required for fastening the insulator to the bracket become fixed together so firmly
by rust, that great difficulty is experienced in removing the nut when it is necessary
to shift the insulator. Now we, when desirable, altogether dispense with the screw
and nut, and use a bolt having a slot at the lower end through which we drive a
wedge.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Crisp Fuller and George Fuller in the Great Seal Patent Office
on the 7th July 1877.
JOHN CRISP FULLER and GEORGE FULLER, both of Stratford, in the County of
Essex. "IMPROVEMENTS IN THE INSULATING SUPPORTS OF TELEGRAPH WIRES."
Hitherto it has been customary to shape the cups of telegraph insulators some-
what after the form of an umbrella or bell, with curved or parallel sides.
According to our Invention we make the insulator more or less in the form of an
inverted truncated cone.
We also further increase the electrical resistance when necessary by corrugating,
serrating, or under cutting the outside surface of the cone.
Figure 1 of the accompanying Drawings is a vertical section, and Figure 2 is a
side elevation of an insulator constructed according to our Invention.
a is the inverted truncated cone insulator, and b, b, are the corrugations,
serrations, or under cuttings thereon.
By the above means we not only provide strength to that portion of the insulator
which has hitherto been found to be weak, and frequently to burst from the
expansion of the iron bolt fixture or support, but with the converging sides of the
cone we improve the insulation by increasing the electrical resistance of the surface.
The peculiar shape of this improved insulator renders it less liable to the retention
of any dirt or moisture on its surface, while the danger from either external or
internal fracture is considerably reduced.
When we combine a separate inner cup with our improved insulator, we do not
permanently cement them together, but we make them separable. In one way we
fit tightly to the inner cup a cap of vulcanized india-rubber or some other insulating
material upon which we screw or force our improved insulator. This separate inner
cup is also shown at Figure 1, where c represents the inner cup, and b¹ the
vulcanized india-rubber or some other insulating material or cement; d is the metal
support insulated, as shown from the inner cup c. By this means we are enabled at
any time to remove at pleasure for examination, cleaning, or renewal without
unbinding the line wire; of course if preferred the inner cup c may be cemented to
the insulator a.
In the iron supports or bolts in common use it is found that the nut and screw
required for fastening the insulator to the bracket become fixed together so firmly
by rust that great difficulty is experienced in removing the nut when it is necessary
to shift the insulator. Now we, when desirable, altogether dispense with the screw
and nut, and use a bolt having a slot at the lower end through which we drive a
wedge; e, e, Figures 1 and 2, show this wedge or cotter passing through a slot in
metal support d.
Having now described the nature of our said Invention and in what manner the
same is to be performed, we declare that we claim as our "Improvements in
Insulating Supports for Telegraph Wires,"-
First. The forming insulators of an inverted truncated cone shape with
corrugations, serrations, or under cuttings on the outside surface thereof, together
with the mode of attaching the insulator to the cup, all substantially in manner and
for the purposes herein-before described and illustrated in the accompanying
Drawings, together with any mere modifications thereof.

page_text: Second. The fastening or securing insulators to posts by bolts or cotters and slots,
substantially as and for the purposes described.
In witness whereof, I, the said John Crisp Fuller, for myself and on behalf of
the said George Fuller, have hereunto set my hand and seal, this Sixth day
of July, in the year of our Lord One thousand eight hundred and seventy-
SAVAN
JOHN CRISP FULLER. (L.S.)