An Improvement in Draw-bar Springs for Railway Rolling Stock.
Year: 1889

page_text: Date of Application, 9th Aug., 1889
Complete Specification Left, 7th Oct., 1889-Accepted, 9th Nov., 1889
PROVISIONAL SPECIFICATION.
An Improvement in Draw-bar Springs for Railway Rolling Stock.
I, JAMES EUSTACE BERKLEY of Nizam's Guaranteed State Railway Company,
Limited of Winchester House, Broad Street in the City of London, Mechanical
Engineer do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved construction of caoutchouc draw bar springs
for the rolling stock of railways. Such caoutchouc springs have heretofore been
confined within a closely fitting metal ring, whereby, when subject to compression by
the draw-bar head, they are liable to undue strains resulting in their fracture.
According to my invention I prevent such fracture by introducing the caoutchouc
block within a cylinder of an internal diameter somewhat greater than that of the
block; thus on the spring being subject to compression by the draw bar head it will in
the first instance expand laterally freely until it meets the sides of the cylinder,
whereupon it will be uniformly supported along its entire side surface by the latter,
and will thus be prevented from becoming unduly strained at any part so as to become
fractured.
The cylinder may be constructed in any suitable manner for attachment to the
carriage under framing; the base thereof may advantageously have a tubular
extension through which the draw bar passes, so as to serve as a guide to the
latter.
000
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improvement in Draw-bar Springs for Railway Rolling Stock.
I, JAMES EUSTACE BERKLEY of Nizam's Guaranteed State Railway Company
Limited of Winchester House, Broad Street, in the City of London, Mechanical
Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement:
My invention relates to an improved construction of caoutchouc draw-bar springs
for the rolling stock of railways. Such caoutchouc springs have heretofore been
confined within a closely fitting metal ring, whereby when subject to compression by
the draw bar head, they are liable to undue strains resulting in their fracture.
According my invention I prevent such fracture by introducing the caoutchouc
block within a cylinder of an internal diameter somewhat greater than that of the
block or partially so; thus on the spring being subject to compression by the draw-bar
head it will in the first instance expand laterally more or less freely until it meets the
sides of the cylinder, whereupon it will be uniformly supported along its entire side
surface by the latter, and will thus be prevented from becoming unduly strained at any
part so as to become fractured.
The cylinder may be constructed in any suitable manner for attachment to the
carriage underframing; the base thereof may advantageously have a tubular extension
through which the draw bar passes, so as to serve as a guide to the latter.
Fig. 1 of the accompanying drawing shews a longitudinal section through a draw-
bar spring constructed according to my above described invention, Fig. 2 shews an
end view of the same.
A is the caoutchouc block through which the draw-bar C passes, and which is situated
within the cylindrical box B.

page_text: The block A may either be made with its outer and inner surfaces plain cylindrical,
the outer surface being of such a diameter as to be out of contact with the box B
when not subject to compression, or it may be formed with one or more portions of its
inner and outer surfaces projecting beyond the other portions so that on the block
being subjected to compression such portions are first brought in contact with the box
and draw-bar, while the other portions only come in contact when the block has been
subjected to a certain degree of compression. By this means the resistance of the
caoutchouc spring to compression by the draw-bar head is rendered a very gradually
increasing one, and the spring is prevented from becoming unduly strained at
any part.
I prefer to make the inner and outer surfaces with corrugation, as shewn, for
producing the above described action. It will be evident that the above described
effect might also be obtained by forming the cylindrical surface of the box corrugated
or with projections.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
A draw-bar spring consisting of the combination of a caoutchouc block with a
cylindrical box or casing into which the block fits in such a manner that, when not
subject to compression, its surfaces are partially or entirely out of contact with the
cylindrical surface of the box substantially as and for the purpose described.
Dated this 7th day of October 1889.
ABEL & IMRAY;
Agents for the Applicant.