IMPROVEMENTS IN BUFFERS AND DRAW SPRINGS FOR RAILWAY CARRIAGES
Year: 1867

page_text: LETTERS PATENT to Joseph Mitchell, of Sheffield, in the County of York,
Spring Maker, for the Invention of "IMPROVEMENTS IN BUFFERS AND DRAW
SPRINGS FOR RAILWAY CARRIAGES."
Sealed the 24th March 1868, and dated the 24th October 1867.
PROVISIONAL SPECIFICATION left by the said Joseph Mitchell at the
Office of the Commissioners of Patents, with his Petition, on the
24th October 1867.
I, JOSEPH MITCHELL, of Sheffield, in the County of York, Spring Maker,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
BUFFERS AND DRAW SPRINGS FOR RAILWAY CARRIAGES," to be as follows:-
The object of my Invention of "Improvements in Buffers and Draw
Springs for Railway Carriages" is to manufacture these articles in a simpler
form and more inexpensive manner than heretofore. To this end I dispense
altogether with the ordinary plunger, and instead thereof I form the spiral
spring of a flat broad piece of sheet steel, the outer coil of which is made to
fit the fixed box and to act instead of the plunger. The outer edge of the
outside coil is bent up into the form of a flange, which fits in a recess made
in the under side of the buffer head, and is secured in its place by a collar or
washer, through which are passed screw bolts or rivets. For a draw spring a
rod provided with a head or plate at one end is passed through the centre of
the spiral spring, which is compressed in the box by applying tractive force to
the end of the rod.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Joseph Mitchell in the Great Seal Patent Office on the
24th April 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
MITCHELL, of Sheffield, in the County of York, Spring Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of October, in the year of our
Lord One thousand eight hundred and sixty-seven, in the thirty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Joseph Mitchell, Her special licence that I, the said Joseph Mitchell,
my executors, administrators, and assigns, or such others as I, the said Joseph
Mitchell, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN BUFFERS
AND DRAW SPRINGS FOR RAILWAY CARRIAGES," upon the condition (amongst
others) that I, the said Joseph Mitchell, my executors or administrators, by
an instrument in writing under or their, or one of their hands and seals,
should particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same to
be filed in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
'
NOW KNOW YE, that I, the said Joseph Mitchell, 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,
reference being had to the Drawing hereunto annexed, and to the letters and
figures marked thereon (that is to say) :-
The object of my Invention of "Improvements in Buffers and Draw
Springs for Railway Carriages" is to manufacture these articles in a simpler
form and more inexpensive manner than heretofore. To this end I dispense
altogether with the ordinary plunger, and instead thereof I form the spiral
spring of a flat broad piece of sheet steel, the outer coil of which by being
made parallel fits in the fixed box and acts as a plunger and instead of the
.ordinary plunger.
In the accompanying Drawing Fig. 1 is an external elevation of a railway
carriage buffer spring at rest constructed according to my Invention, Fig. 2 is
a vertical section of the same, and Fig. 3 is also a vertical section, but shewing

page_text: the volute spring compressed; Fig. 4 is a sectional elevation of the buffer, the
volute spring being shewn in elevation, and the external case and buffer head
in section; Fig. 5 is a plan view of the under side of the buffer head, shewing
the circular groove into which the volute spring fits.
The outer edge of the outside coil of the volute spring a fits into a circular
groove made in the under or inner side of the buffer head, as seen at b, Fig. 5.
The bar c is secured in any convenient manner to the buffer head, and passes
through the cross bar or plate d¹ in the case or box d, d, all the parts being
held securely by the key or cottar c¹. If preferred the outer edge of the
outside coil may be bent up into the form of a flange and made to fit in a
recess in the under side of the buffer head, as shewn at e in the plan view,
Fig. 6, and is secured in its place by a collar, washer, or ring f, through
which are passed screw bolts or rivets 9, 9, as shewn in Fig. 6. For a draw
spring a rod provided with a bead or plate at one end is passed through the
centre of the spiral spring, which will be compressed by applying tractive
force to the end of the rod, as shewn at Fig. 7.
As a modification the volute spring a may be attached direct to the framing
of the waggon or carriage without the box or case d, and may be made to
act either as a buffer or draw spring, as seen at Fig. 8.
Having now described my Invention of "Improvements in Buffers and
Draw Springs for Railway Carriages," and having explained the manner of
carrying the same into effect, I claim as the Invention secured to me by
Letters Patent as aforesaid, adapting or combining the volute or spiral spring
with the outer box or case in such a manner as to cause it to act as and serve
the purpose of a plunger, as herein set forth.
In witness whereof, I, the said Joseph Mitchell, have hereunto set my
hand and seal, the Twenty-second day of April, in the year of our
Lord One thousand eight hundred and sixty-eight.
Witness,
JOSEPH GOLDSACK,
84, Oxford Street,
Sheffield.
JOSEPH MITCHELL. (L.S.)