Improvements in Felt used on Permanent Way.
Year: 1895

page_text: COMPLETE SPECIFICATION.
Improvements in Felt used on Permanent Way.
I, PAUL KNOCH of Ottenstrasse, Adlershof, near Berlin, in the Empire of
Germany, Felt Manufacturer, do hereby declare the nature of my said invention
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
The elastic felt bed-plates hitherto used present this drawback that they are
uniformly impregnated throughout, so that the portion of the surface on which
rests the iron bed-plate, or even the foot of the rail, possesses the same degree of
elasticity as the remaining portion of the bed plate.
Owing to the softness of the bed-plate necessitated by its elasticity, the rail, in
the event of no iron bed-plate being used, does not obtain a sufficiently secure
support, and it frequently happens that the rail foot cuts into the felt, reudering
it useless.
In the case, however, of the bed-plate prepared by the process herein described
the drawback of its being cut by the foot of the rail is completely done away
with, the upper surface forming, to the depth of 4 millimetres, a compact and
firm layer.
The pressure of the foot of the rail is thus brought to bear not merely on the
portion with which it comes into contact, but is distributed on the greater part of
the surface of the felt the possibility of the rail-foot cutting into the solid upper
layer of the felt is thus entirely avoided.
This clastic bed-plate can, therefore, be used also without the interposition of
an iron bed-plate, without in the least diminishing the durability of the felt
bed-plate.
These advantages are generally obtained by impregnating the surface of the felt
with indurating solutions.
The process of impregnation may, for instance, be carried out in the following
manner:
The felt having passed through the first stage of preparation, the object of
which is to enhance the durability of the whole of the bed plate, it is covered with
a layer of glue, which is made to permeate to the depth of 4 millimetres; this
portion of the felt is then treated with chrome-alum, bi-chromate of potash,
bichromate of soda, or "formalin and the plate is then left to dry; or the
upper surface of the felt is impregnated with a solution of india-rubber, which is
subsequently vulcanized; or the bed plate is to the depth of + millimetres,
saturated with a solution of resin.
In the event of there being a possibility of the felt bed-plate being cut on both
sides, both the top and bottom surfaces should be impregnated in the manner
hereinbefore described.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. An elastic felt bed-plate, which has its upper or under surface hardened, in
the manner and for the purpose described.
2. An elastic felt bed-pinte, which has its upper and under surfaces hardened,
in the manner and for the purpose described.
3. An elastie felt bed-plate, the characteristic feature of which is that one or both
of its upper and lower surfaces is or are, impregnated with a solution which either

page_text: hardens spontaneously, or upon being saturated with glue and then treated with
chrome-alum, bi-chromate of potash or soda, or with a solution of resin substantially
as described.
4. An elastic felt bed-plate, the characteristic feature of which is that one or both
of its upper and lower surfaces is or are impregnated with a solution preferably
of india-rubber, and then vulcanized or otherwise indurated, substantially as
described.
Dated this 4th day of September 1895.
WILLIAM J. MUNDEN,
106 Priory Park Road, Kilburn, London, N.W.,
Agent for the Applicant.