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

page_text: Date of Application, 15th June, 1897-Accepted, 31st July, 1897
Improvements in and relating to Insulators for Electric Conductor
Rails.
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 which are employed for supporting and
insulating the conductor rail of a third-rail electric railway system.
In the accompanying drawings, Fig. 1 is a plan view of our improved insulator
applied to a conductor rail; Fig. 2 is a sectional view of the same; Fig. 3 is a
modification; Fig. 4 is a sectional view of our preferred form; Fig. 5 is a plan view
of an anchor insulator; and Fig. 6 is a sectional view taken on the line 6-6 of
Fig. 5.
In Fig. the conductor rail A is supported by insulators C which engage with the
rail between the tread and the lower flange and which are mounted on supports D on
opposite sides of the rail. The insulators C consist of a substantially rectangular body of
porcelain, vitrified brick or other insulating material, and each insulator is provided
with a socket or opening C¹ with which the upper end of the arm D2 of the support D
engages; between the insulator and the rail is placed a sheet of lead which compensates
for slight irregularities in the insulator or rail and ensures a good fit between them.
The supports D are preferably made of malleable iron on account of its toughness, and
each support is provided with an enlarged base secured to the cross tie by lag
screws F, and an arm 12 projecting upward and inward toward the rail. On the upper
end of the arm D2 is a rounded portion which fits into a correspondingly rounded
socket on the insulator C; this reduces the liability of the insulator to split. The
arm D2 is rectangular in cross section, and being thin in the vertical direction, a
certain amount of resiliency is provided; this permits the cross tie on which the
insulator is supported to move slightly independently of the conductor rail as the car
trucks pass over the traffic rails, thereby relieving the strain on the insulator and
decreasing the liability of breakage.
Extending parallel with the rail A and on both sides of it are guard planks B which
are mounted at an angle and secured in position by angle irons E; the latter are
secured to the cross ties and guard-planks by lag screws and bolts. The top portion
of the planks B extends slightly above the top of the rail A, protecting it from
dropping wires or pieces of metal.
In Fig. 3 a slight modification is shown; the insulator C is provided with two
sockets for the reception of arms D2, D3 which form a part of the support D. The
arms D2, D3 are constructed in the same way as the arm D2 in Fig. 1, with the

page_text: exception that they are slightly narrowed. It is evident that by increasing the
number of arms and the length of the body of insulating material C, the insulator
may be adapted for much heavier rails.
In Fig, 4 we have shown the preferred form of our insulator; a standard T rail is
employed as a conductor and is supported on both sides by insulators C which are
constructed in the same manner as those described in connection with Fig. 1.
Between the insulators and the rail are sheets of lead G which ensure a good fit between
them and the rail. The supports D) are made of forgings, or if desired, of punchings;
the outer ends of the arms are curved as shown at D', which fit into the sockets on
the insulators C. By varying the thickness of the arms; any degree of resiliency
may be obtained; the arms are so arranged that a slight movement of the rail is
permitted in a vertical direction but not in a lateral direction.
In Figs. 5 and 6 we have shown an insulator combined with means for anchoring
the conductor rail A against a forward or backward movement.
In third-rail traction systems, to which our invention is particularly adapted, we
have found that the conductor rail tends to creep in the direction in which the trains
travel; this creeping is objectionable, and more particularly so where the system is
divided electrically into sections; in this case it sometimes even causes the adjoining
sections to touch and thus unite the sections into one.
The insulators C are provided with two sockets into which project the arms D2, D³,
of the support D; the support is secured to the cross tie by lag screws F. A bolt H
is passed through a hole I in the web of the rail and thereby bolts the rail to the
insulators and insulator supports. The bolt hole is made slightly larger than the bolt,
to provide a limited adjustment for the insulator.
The arms of the support D in the present instance are preferably more rigid than
those in Fig. 4, on account of the increased strain due to the bolt H. engaging with the
web of the rail.
Having now particularly described and ascertained the nature of our said inven-
tion (as communicated to us from abroad) and in what manner the same is to
be performed, we declare that what we claim is :-
1. The combination of a conductor rail, a body of insulating material situated each
side of and supporting the rail, and a support for. each body of insulating material
permitting a limited amount of vertical movement of the conductor rail.
2. The combination of a conductor rail, a body of insulating material situated on each
side of the rail and engaging therewith between the flange and tread, and a separate
support for each body of insulating material.
3. In an anchor insulator for a conductor rail, the combination of a body of insulating
material engaging with the conductor rail, a support for the insulating material
secured to a cross tie, and ineans for preventing a movement of the conductor
independent of the insulator.
4. In an anchor insulator, the combination of a conductor rail, a body of insulating
material applied to each side of the rail, a separate support for each insulator, and
means for connecting the conductor rail and the insulators together.
5. As an article of manufacture, a body of insulating material having part of its
outer periphery conforming in shape to that portion of the T rail between the flange
and tread, and provided with openings or holes in which its support is secured."
6. In a third-rail electric railway system, the combination of a conductor rail,
insulators supporting the rail at suitable intervals, guard planks extending above and
parallel with the rail on both sides thereof, and angle irons supporting the guard planks
at an angle to the conductor rail.
7. The combination of a conductor rail, insulators fitting between the flange and
tread of the rail, and upwardly extending supporting arms for the insulators
supporting the rail from the sides above the surface of the cross ties, as set
forth.

page_text: 8. The combination of a conductor rail, insulators seated between the flange and
tread of the rail on each side of the web, said insulators having sockets, as described,
and metal supports having arms projecting into the sockets, whereby the rail is
supported from the sides, substantially as described.
T
1000