Improvements in and relating to lightning conductors
Year: 1885

page_text: We RICHARD PENTNEY EIDSFORTH and FRANCIS JOHN MUDFORD both of
4 Jackson Road, Holloway in the County of Middlesex, Electrical Engineers do
hereby declare the nature of our invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement -
Our Invention of Improvements in and relating to lightning conductors has
reference to the means of uniting the parts of the lightning conductor together and
of securely attaching it to the building or structure to be protected from the effects
of lightning.
For the purpose of affording a more accessible line of discharge of less electrical
resistance to an electric current than the building or structure to which the
lightning conductor is attached it is important that the joints or unions of the
several parts comprizing the lightning conductor be electrically perfect. As
ordinarily constructed, lightning conductors consist of a pointed rod of metal of
good electrical conductivity, termed the upper terminal, its point usually projecting
above the uppermost part of the structure it is intended to protect; the lower end
of this upper terminal is connected to a conductor usually a copper wire rope, or a
flat strip or tape of the same metal, which is carried down the building and united
beneath the surface of the ground to a metal plate or other well known form of
earth connection. On large buildings more than one upper terminal is employed,
each provided with a conductor, and the several conductors of the upper terminals
are sometimes led to a convenient point on the building and united to a conductor
connected at its lower end to the earth connection. Now it is most essential
to the successful operation of lightning conductors that the union of the several
parts thereof above named should be electrically perfect, and that the lightning
conductors so constructed be securely fixed to the building intended to be protected
thereby.
Many methods of uniting the several parts of lightning conductors, such for
example as scarfing, screwing or rivetting them to each other, have been employed,
but however mechanically perfect such joints may be made, they are liable to
open owing to expansion and contraction due to changes of temperature, and admit
TD 01

page_text: moisture causing corrosion which greatly increases the electrical resistance of the
lightning conductor, and consequently much impairs its efficiency. It has further
been proposed to unite the several parts of lightning conductors together by
soldering them to each other but this method of ensuring a metallically perfect
joint is very difficult to effectually carry out when as is usually the case the
several parts are fixed to the building before being united to each other owing to
their exposed and elevated position, and further the hot irons, fire-pots or spirit-
lamps which are indispensable in making soldered joints are a great source of
danger to the building on which they are used from the possibility, for example,
of a heated iron or spark from a fire-pot falling upon and igniting an inflammable
part of the building. Now, according to our Invention we obviate the defects and
difficulties before mentioned by the employment of improved means of uniting the
parts of the lightning conductor which admits of their being put together before
the lightning conductor is attached to the building or structure to be protected,
and by the use of peculiar devices for securely attaching the lightning conductor
to such building or structure all as hereinafter described with reference to the
several figures on the accompanying sheet of drawings, the same letters of reference
on which indicate corresponding parts in all the figures.
Figure 1 of the accompanying drawings is a sectional elevation illustrating the
operation of uniting the parts of a lightning conductor.
Figure 2 is a sectional elevation representing a portion of the complete conductor
in its finished state.
Figure 3 is a diagrammatic view of a portion of a building or structure shewing
the lightning conductor attached to the building or structure by means of peculiar
supporting devices.
Figures 4 and 5 are details representing one form of device or support which we
employ, Figure 4 being a plan and Figure 5 a side elevation of the same with a
lightning conductor in each view shewn secured by it.
Figures 6 and 7 illustrate in vertical and horizontal section the application of
the Invention to a lightning conductor having multiple upper terminals.
In the case of a lightning conductor consisting of a single upper terminal and
one conductor, we proceed in the following manner :-
Having determined the most suitable position for the upper terminal we ascertain
by measurement the length of conductor required to reach from the upper terminal
to the earth connection; we then obtain a conductor of suitable length and cross
section, of copper wire rope, copper tape, or of any other approved form of inaterial.
Previously to securing the upper terminal in position on the building we unite it to
the conductor. This we effect in the manner next hereinafter described. In the
case of a wire rope conductor we drill a hole a (Figure 1) up the lower end of the
upper terminal A or of an attachment to it, the said hole being slightly larger in
diameter than the conductor B to which the upper terminal A is to be united; we
then invert the upper terminal as shewn in figure 1, tin the interior of the hole a,
insert therein the end of the conductor B also previously tinned, and run solder
between them, thus producing a solid joint metallically perfect. Figure 2 shews
the parts thus united together and ready to be attached to the building or structure
to be protected, the metallic connection being indicated at a2. If the conductor B
employed, is in the form of a flat strip or tape of suitable metal as shewn in
figure 5 we unite it to the upper terminal by making a slot at a in the lower end
of the latter slightly wider than the thickness of the conductor B then tin the
interior of the slot and the surface of the conductor B, insert the latter in the slot,
rivet them together, and finally solder them. Similarly in the case of a conductor
of any other section to be united to the upper terminal, the chamber or opening in
the upper terminal being made of corresponding shape for its reception, and the
parts being tinned and soldered together as herein before described. By thus
uniting the conductor to the upper terminal before fixing the latter to the building
a perfect joint is made and there will be no danger to the building from sparks o
hot irons.

page_text: We then proceed to fix the upper terminal to the building in the following
manner
C (Figures 4 and 5) is a bracket provided with tang c which may be built
into the brick work in the process of constructing the building, or let into the
brickwork and secured therein by grouting with cement, or attached to the
building in any other well known way; and the bracket is also furnished with
flanges c¹ extending sideways and downwards therefrom so as to form a good
bearing for it against the face of the brickwork. The outer end of the bracket C
is, moreover, hollowed out to conform to the circumference of the terminal A which
is provided near its lower end with a collar a¹ which when the terminal A is in
position in the bracket C rests upon the upper surface of the latter and forms a
good bearing for the terminal A. A removable strap D, shown in position on the
bracket C in Figures 4 and 5, is employed for securing the terminal A to the
bracket C. The strap D fits closely the sides of the bracket C and is slotted at d,
the inner side of its curved end being shaped so as to fit the circumference of the
terminal A. In the operation of securing the terminal A to the bracket C, the
terminal A is first placed against the outer end of the bracket C, the collar a¹
resting upon the upper surface thereof; the strap D is then slipped over the
terminal À so that its upper edge shall be in contact with the collar a¹ and its
ends embrace the bracket C, the slot d therein nearly coinciding with a slot d¹
formed in the bracket C; the gib E and cotter E¹ are then inserted in the said
slots and by driving in the cotter E¹ the strap D will tightly grip the terminal A
against the bracket C, thus securely attaching the lightning conductor to the
building. The conductor B shewn attached to the upper terminal A in Figure 5
consists of a tape or strip of conducting material, in lieu of a wire rope as
represented in Figures 1, 2 and 3.
The last mentioned Figure (3) shews diagramatically the lightning conductor A, B,
attached to the building. As will be seen in this figure another bracket C¹ fixed
in the building a short distance above the bracket C, and having a strap D¹
similarly gripping the terminal A, is employed for more securely attaching the.
terminal A to the building. The bracket C only differs from the bracket C in that
it has no flange at c¹ extending downwards as has the bracket C. The strap D¹
grips and secures the terminal A precisely in the same manner as the strap D.
The straps D and D¹ may constitute an integral part of the terminal A being
formed thereon in the process of manufacture Or in lieu of the straps D D' being
formed on the terminal A they may be formed on the brackets C C and so arranged
as to embrace projections provided on the terminal, the parts being slotted and
secured together by gibs and cotters as before.
It will be observed that the herein before described support for the lightning
conductor consists of two principal parts, one securely attached to the building, the
other formed on, or attached to, or gripping the lightning conductor. It is obvious,
therefore, that other modifications of the support comprizing these two principal
parts will readily suggest themselves to those skilled in the art and come within
the scope of our Invention.
In some cases the support herein before described with reference to Figures 4
and 5 may be advantageously employed in connection with lightning conductors,
the parts of which are united together in a manner different from that hereinbefore
described, and illustrated in Figures 1, 2, 3 and 5.
When from the form and size of the building more than one upper terminal is
employed, each terminal is provided with a separate conductor, and it is desired to
unite these conductors at a convenient point on the building to a common conductor
leading to the earth connection, We prefer in this case also to make all the
connections of the several parts of the lightning conductor before securing it in
position; ascertaining by measurement the lengths of the several conductors, we
unite them to their upper terminals by soldering in the manner herein before
described and to the common conductor leading to the earth connection also by
Boldering by the aid of peculiar junction pieces.

page_text: In
This modification is illustrated in Figures 6 and 7. In these figures F, G and H
represent ends of wire rope conductors (any required number of which may be
employed) connected at their other extremities to upper terminals in the manner
hereinbefore described. J is a junction piece employed for connecting the con-
ductors F, G, H to the common conductor B leading to the earth connection.
order to secure conductors F, G, H and B in the junction piece J, the latter is
preferably first placed in a position inverted to that shown in Figure 6, the small
chamber b for receiving the conductor B being uppermost; the interior of 6 is
tinned, as also is the end of the conductor B, the latter is then inserted in the
chamber at b which is of slightly greater diameter than B and solder run into
the annular space between them. The junction piece J is then placed with the
chamber 6 uppermost, which chamber is cast or otherwise formed in the junction
piece J of such size as just to receive the ends of the conductors F, G, and H
therein, as shown in the drawings. The interior of the chamber b' and the ends of
the conductors F, G, H having been tinned, the latter are inserted in their place
and solder run in filling up all the insterstices between them and the sides of the
chamber 6, the conductors being thus metallically united to the junction piece J
and to the common earth conductor B. The junction piece may be attached to the
building or structure by means of bolts or other fastenings passing through lugs j j
on the junction piece or in any other suitable manner. It will be understood
that the junction piece J should be made of a material of good electrical con-
ductivity. When the conductors are, as is frequently the case, flat strips or tapes
of copper or other suitable metal the chambers b.b¹ are made of corresponding size
and section.
The conductors as they are carried along the building are secured thereto by
staples of the usual form driven into the walls at convenient distances apart.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we wish it to be
understood that we do not claim broadly the uniting together of the several parts
of lightning conductors by soldering, but we declare that what we claim is
1st A lightning conductor the several parts of which are united together
substantially in the manner and by the means herein set forth, in combination
with a device for attaching the lightning conductor to the building or structure to
be protected, such device consisting of two principal parts one of which is securely
fixed to the said building or structure whilst the other part is formed on, attached
to, or grips the lightning conductor to be supported, and is connected to the first
part, all substantially as herein before described.
2nd The device for attaching lightning conductors to buildings or structures
substantially as herein before described with reference to Figures 3, 4 and 5 of the
accompanying drawings."
3rd In lightning conductors having two or more upper terminals, the mode of
and means for uniting the conductors proceeding from such terminals to a common
conductor leading to the earth connection, substantially as bereinbefore described
with reference to Figures 6 and 7 of the accompanying drawings.
Dated this 2nd day of Dec. 100