Improvements in Insulators for Electric Conductor Rails and Feeders.
Year: 1897

page_text: Date of Application, 15th June, 1897-Accepted, 31st July, 1897
COMPLETE SPECIFICATION.
Improvements in Insulators for Electric Conductor Rails and
Feeders.
We, THE BRITISH THOMSON-HOUSTON COMPANY, LIMITED, of 83; Cannon Street, in
the City of London, Electrical Engineers, do hereby declare the nature of this
invention (which has been communicated to us from abroad by Sam H. Libby of
Schenectady, County of Schenectady, State of New York, United States of America)
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The present invention relates to insulators employed for insulating and supporting
the conductor rail of a third-rail electric railway system.
The invention has for one of its objects to provide an insulator having a rail clamp
which may be secured to or loosed from the conductor rail by a slight angular
movement, and where position upon the main body of insulating material is maintained.
by frictional engagement.
The invention further has for its object to lessen the cost of manufacture, and to
provide an insulator which occupies a minimum amount of vertical space, at the same.
time presenting a large surface over which moisture is obliged to creep before it can
damage the insulation of the system. .
The invention further relates to the means employed for tapping a feeder into the
conductor rail.
In the accompanying drawings, Fig. 1 is a plan view of our improved insulator
secured to a contact rail; Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1;
Figs. 3 and 4 are respectively a plan and side elevation of the insulator applied to a
standard T. rail; Fig. 5 is a side elevation of my improved feeder tap; Fig. 6 is a
sectional detail of the same.
In Figs. 1 and 2 the conductor or contact rail A is made with a special cross
section, in order to reduce its vertical height to a minimum; sloping downward and.
away from the centre of the rail are side portions B, B1 which correspond to the
flanges of a standard T rail and are engaged by lugs on the rail clamps. The rail.
clamp C is provided with lugs C1 and C2; these are arranged on opposite sides of the
centre and are displaced to permit the clamp to be applied to the bottom of the rail A,.
after which it. is. slightly rotated and the lugs C₁, C engage with the sides B, B₁ of
the rail. The centre of the clamp A is provided with a circular tapered hole into:
which projects the upper end of the insulator D; the latter is made of porcelain or
other good insulating material, and is provided with a slight taper which ensures good
frictional engagement between it and the rail clamp. The insulator D is supported
by a metallic base E which is provided at its centre with a vertical extension E'; the
latter is screw-threaded or roughened, and between it and the insulator is a filling
of suitable cement F. The base E. is provided with holes so that it may be spiked
to a cross tie.
The outer surface of the insulator may or may not be glazed. We have found
however that there is less liability of the moisture creeping over the surface if it is.
glazed, and also that dirt does not stick so readily.

page_text: The weight of the conductor rail A is sufficient to prevent the clamps from turning
after they have been mounted in position, and by extending the body of insulation D
through the rail clamp, side movement of the conductor rail A is prevented.
Figs. 3 and 4 show our invention applied to a standard T rail. The vertical height
of the rail being greater than the one of special cross section shown in Fig. 1, the
insulator D is mounted on a base E provided with upwardly extending extensions G
which rest on the cross ties H, H', and are secured thereto by lag screws I; this
permits the base of the insulator to drop below the top of the ties. The construction
of the clamp C and the insulator D is the same as shown and described in connection
with Fig. 1.
Figs. 5 and 6 show a device for tapping a feeder into the conductor rail.
Supported from the cross ties H, H by arms K' is an insulator J comprising a metal
cylinder K within which is the lead covered feeder cable L. Between the cable and
the cylinder is insulating material M which is applied while in a plastic state.
Surrounding the cylinder K is a cap K2 of insulating material and secured to the
cylinder by any suitable means; in the present instance the cap and cylinder
are screw-threaded, and between them is a small amount of the insulating
material M:
At the upper end of the cable L the insulation is removed and a connector L' is
soldered or otherwise secured thereto; the outer end of the connector L' is provided
with a tubular projection L2 Fig. 5 into which is driven the pin L³; this expands the
tube L² and ensures good electrical contact between the connector L₁ and the
rail.
'
Having now particularly described and ascertained the nature of our said invention
(as communicated to us from abroad) and in what manner the same is to be
performed, we declare that what we claim is :-
1. In a conductor rail insulator, the combination of a metal base, a body of
insulating material mounted upon the base, a rail clamp secured to the conductor rail
and prevented from moving independently of the insulator by frictional engagement
therewith.
2. In a conductor rail insulator, the combination of a metal base, a body of
insulating material, mounted upon the base, a clamp secured to the conductor rail
by an angular movement, and friction surfaces on the insulating base and rail
clamp preventing the rail clamp from moving.
3. In a conductor rail insulator, the combination of a metal base, a body of
insulating material mounted thereon and provided with a tapered portion, a rail
clamp mounted on the tapered portion of the insulator, and lugs on the rail clamp
engaging with the conductor rail.
4. In a conductor rail insulator, the combination of a metal base, a body of
insulating material having an exterior tapered portion, a rail clamp having a hole
tapered to correspond with the taper on the insulating material, and lugs on the rail
clamp engaging with the conductor rail.
5. In a conductor rail insulator, the combination of a metal base; means
permitting the base to be dropped below the top of the cross ties, a body of
insulating material mounted on the metal base, and a rail clamp provided with lugs
for engaging with the conductor rail.
6. In a conductor rail insulator, the combination of a metal base, extensions on the
base secured to the cross ties and permitting the base to be dropped below the top
of the cross ties, a body of insulating material mounted on the base, and a rail
clamp.
7. In a feeder insulator, the combination of a metal cylinder, extensions from the
cylinder secured to the cross ties, insulation between the feeder cable and the cylinder,
and a connector secured to the cable and supply conductor.
8. The combination of a conductor rail, a fixed non-rotating insulator, and a metal
clamp between the rail and the insulator free to rotate on the insulator and having lugs
which are clamped upon the rail by a rotary movement of the clamp.

page_text: 9. The combination of a metal base adapted to be fixed to a support, a porcelain or
other vitreous insulating body having a tapered circular outline and fixed to a stem
upon the metal base, and a reversely tapered inetal clamp surrounding the insulating
body and free to turn thereon, said clamp having side flanges forming seats for a
conducting rail, and clamping lugs which are clamped upon the rail by a rotary
movement.
1005