|
SPECIFICATION. To all whom it may concern: Be it known that I, DAVID P. EMMINGER of the city of Harrisburg, county of Dauphin, and State of Pennsylvania, have invented a new and Improved "Insulator for Telegraph Purposes;" and I do hereby declare the following to be a clear, and exact description of the same, reference being made to the accompanying drawing making a part of this specification, and to the letters of reference marked thereon. The nature of my invention consists in constructing my improved "insulator" that dust and dirt are prevented from accumulating upon its outer surface. Also in reducing points of contact of the conducting-wire with the insulator, in a great degree, by a peculiar method of construction of said insulator. In the drawing, Figure 1 represents a perspective view of the device. Fig. 2 is a longitudinal section of the insulator, taken through its center. Fig. 3 is an interior view as seen from the lower edge. Fig. 5 is a top view of the insulator, Figs. 4, 6, and 7 are views of the insulator and the upper end of its supporting-pin. These views as well as Figs. 3 and 5, arc on an enlarged scale, to render the details more clear. Figs. 1 and 2 are drawn to the scale shown in the drawing. In all the views in which it appears A represents the body of the
insulator. It is
constructed of glass, and is made conical form, as is shown in Figs. 1,
2, and 6. Upon its outer surface, a proper distance from the upper
rounded end, four rhombus or lozenge-shaped projections, a a a a, are
formed. These projections have circular or
rounded notches formed in their outer edges a proper distance from their
terminations. They are
intended to receive and retain in place the binding wire that secures
the conducting-wire to the insulator.
The projections may be increased in number if desired.
Four are considered sufficient, and that number is preferred on
account of facility of construction.
The lower part of the body of the insulator is hollowed out in
cup-form, as seen in the sections in Figs. 2 and 6.
From the upper part of this cup, concentric with the outer
surface, a conical recess extends upward.
It is made of such relative height to the insulator's length that
a significant portion of material will be allowed above it to ensure
strength. Upon the Surface
of this recess 4, at points directly opposite each other, two knobs or
rounded projections are formed, as seen in Figs. 2 and 6. The recess 4,
(see Fig. 6,) is designed to receive the supporting-pin B, (see Figs. 2
and 4.) This pin is made of
wood. The lower part is
rounded, as is shown, to enter the sustaining-bracket.
The upper end, (see Figs. 2 and 4,) is reduced so as to form a
shoulder around its body. Two
parallel grooves, i i, are cut at opposite points in the conical
part that projects above this shoulder.
These grooves i i are made of sufficient depth and width
to allow |
 |
|
|
the easy insertion of the projecting knobs 1 2 that are formed on the wall of the recess 4. The shoulders are cut away so as to form inclines that slope from one edge of each of the grooves i i, as is shown in Figs. 2 and 4. The neck formed below the shoulder is made a little smaller than the distance between the projections 1 2 in the recess 4 in the body of the insulator. The thickness of wood between the bottoms of the grooves is the same as the diameter of the neck above mentioned. It will he observed that from this method of construction, the supporting-pin B can be instantly and securely locked into the recess in the insulator by inserting its upper end in the lower end of said recess, entering the knobs 1 2 in the grooves i i; then, by pushing and at the same time turning the insulator slightly, the knobs 1 2 engage below the shoulders s s, and rigidly connect the two together. It is a fact well known to experts in telegraph
construction that the ordinary cylindrical glass insulator is very
defective in operation. This
is mainly owing to the fact that dust and dirt accumulate around the
groove and upon the surface below the groove until a partial conducting
medium is formed between the wire and the supporting-pin.
I have overcome this difficulty by constructing the body of the
insulator of conical form, thus permitting the rain to dash upon every
part of its surface and wash it clean.
The peculiar form of the grooved projections a a a a also
permits the rain to perfectly cleanse them of dirt.
Another advantage is obtained by this method of construction,
which is, that the bearing surface between the conducting wire and the
insulator is reduced to a minimum. I am aware that this feature has been
attempted before in a cylindrical insulator: A rigid metallic band
encircling it, bearing upon knobs formed on the surface, and held in
place by a set-screw. This
insulator is defective from the fact that the unyielding nature of the
connection between the band and the insulator causes breakage by the
action of frost. I avoid this by using a binding wire to connect the
main wire with the insulator, which, by its elasticity, preserves the
glass from breakage. I
therefore disclaim the use of rigid encircling bands on cylindrical
insulators. But— What I do claim as new, of my invention, and desire to secure by
Letters Patent of the United States, is— An insulator constructed with its outer surface conical or
flaring from the apex to the base, provided with the peculiarly-shaped
and grooved projections a a a a, as herein set forth and for the
purposes specified.
DAVID R. P. EMMINGER.
Witnesses: WM. P. PATTON, GEO. H. HEITZMANN. |