IMPROVEMENTS IN THE MEANS AND APPARATUS FOR ATTACHING TELEGRAPH WIRES TO INSULATORS, IN THE CONSTRUCTION OF INSULATORS SPECIALLY ADAPTED TO SUCH APPARATUS, AND ALSO IN THE CONSTRUCTION OF PROTECTING SHIELDS AND GUARDS FOR USE THEREWITH, WHICH IMPROVEMENTS ARE PARTLY APPLICABLE TO EXISTING FORMS OF INSULATOR
Year: 1872

page_text: PROVISIONAL SPECIFICATION left by William Alexander Lyttle at
the office of the Commissioners of Patents, with his Petition, on
the 29th October 1872.
I, WILLIAM ALEXANDER LYTTLE, of the Grove, Hammersmith, in
the County of Middlesex, Engineer, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE MEANS AND APPARATUS FOR
ATTACHING TELEGRAPH WIRES TO INSULATORS, IN THE CONSTRUCTION OF INSULATORS
SPECIALLY ADAPTED TO SUCH APPARATUS, AND ALSO IN THE CONSTRUCTION OF
PROTECTING SHIELDS AND GUARDS FOR USE THEREWITH, WHICH IMPROVEMENTS ARE
PARTLY APPLICABLE TO EXISTING FORMS OF INSULATOR," to be as follows:-
Instead of attaching the telegraph wire to the insulator as at present
by means of small binding wire passed several times round the groove
encircling the top of the insulator and at the same time round the
telegraph wire, I fit an U or horse-shoe shaped iron rod to the said
groove, and secure the telegraph wire to the ends thereof, by means
of a wedge key or screw nuts, in the following manner :-When the
fastening is to be done by a wedge, the legs of the U are made of
unequal length, and are hooked upward and backward in such a way
that when the telegraph wire is laid inside the hooks, and therefore

page_text: across the open end of the U the latter can be slipped down upon the
insulator, and placed in the binding groove. A wedge key with one.
or more of its edges slightly serrated is then driven home between the
telegraph wire and the hook at the longer end or leg of the U. If the U
is made a sufficiently casy fit the telegraph wire may thus be jammed
firmly into the portion of the same binding groove between the legs of
the U. Instead of jamming this wire into the groove a cross bar of
metal or ebonite may be provided, fitting on by slots or holes in its ends
to the legs of the U, and furnished on one side with a rib to fit into
the binding groove in the insulator, and upon the other side with a
longitudinal recess, into which the telegraph wire can be jammed by
the wedge key as hercin-before described. One edge of this wedge will
lie along the wire, and the other will press against the inside of the
hook. If desired, a wedge may be fitted to the end of each leg of
the U. Instead of jamming the telegraph wire by one or more wedges
the ends of the U may be made straight, each being threaded with a
screw and provided with a small nut, the face of which next the wire
should be so grooved or roughened like a rasp that when once jammed
home against the wire it shall have no tendency to loosen. With the
latter object it may also be desirable to make one screw left-handed and
the other right-handed, so that any pull of the wire which shall tend to
loosen one nut shall equally tend to jam the other more tightly.
In order to diminish as much as possible the metallic surface in contact
with the insulator, and, therefore, to increase the resistance to leakage of
the clectric current, it is desirable to bend the U so that it shall cither
be like a gothic arch so as to touch the insulator groove only at its two
sides, or it may resemble three sides of a rectangle with the angles slightly
rounded. In the latter case it will touch the insulator at three points only.
If the insulator is so constructed that a cross section of its top is of
horse-shoc outline it will not be necessary to employ the metal or
ebonite cross piece above-mentioned. The wire will be jammed against
the flat side into a groove provided for the purpose.
In order to provide for the more perfect cleansing of such insulators
when dirty, the employment of the U rod binding, rendering it for the
first time possible to disconnect the binding of the telegraph wire
without destroying such binding, I provide the insulator when desired
with the following shank or stem which can be easily detached both
from the stoneware of the insulator and the arm of the telegraph pole,

page_text: I make a shank of cast iron, either ordinary or malleable, with a
rough screw thread cast on its top, or with its surface indented or lined
so as to be rough like a file over that part which is now made fast into
the insulator head. I also provide it with a projecting collar having
either a flat under surface to fit against the flat side of a cross arm, or
angular to fit upon an angle of the arm if the latter is set upon the
pole with one of its diagonals in the vertical line parallel to the pole.
When side guards are required to perform the functions of the
present hoop guards a rod of wrought iron bent into an U or a rect-
angular shape may be enclosed in the mould when the shank is about
to be cast in such a position that the middle of the U shall pass through
the collar, and so give the shank the appearance of a three-pronged
fork or trident. One side of the U may be omitted if desired, so as to
have a guard on one side only. Instead of using wrought iron, the
entire shank and guard as described may be of cast iron. Through the
bottom end of this shank below the collar I provide a slot at such a point
that a key driven through it shall jam either against the arm or a
suitable washer acting against the under side or edge of the arm through
which the shank passes, and so secure the shank with the insulator cup
thereon in a vertical position. To attach an insulator cup to the top
of this shank it is only necessary to wind round the screw threaded or
roughened surface in a hot or cold state a spiral of soft cotton hemp
or other fibrous material, or a woven covering well smeared or dipped
either with plaster of Paris paste, or in shoemakers or any other like
wax, but preferably in a wax in which the pitch and most of the rosin
used in making shoemakers' wax are replaced by solid paraffine. The
shank is then screwed home tightly into the cylindrical hole now
provided in the insulator. It would be an advantage, but not indis-
pensable, if this hole were formed as a female screw.
In order to protect such and other insulators from breakage when
the U binding is employed, I provide, when desired, a shield or hood
of sheet iron or malleable cast iron open at the top, and I drop it down
over the insulator, which must be able to pass freely through it; then
adjust the U in its place in the groove, and next raise the hood so as
to cause two vertical slots provided for that purpose in its upper edge to
pass on to the two legs of the U, either between the telegraph wire and
the insulator when no cross piece is employed, or between the cross
piece and the telegraph wire. In the latter case the portion of the

page_text: hood between the slots should conform in shape to the recess provided'
for the wire in the cross piece; in the former case, it should be ridged.
so as to fit into the insulator groove; in either case it should be recessed.
upon the outside so as to receive the telegraph wire. When the wedge-
key or nuts are tightened, the U, the shield, and the telegraph wire are
then at once secured. This hood or shield should not touch the insulator
anywhere except round its top.