IMPROVEMENTS IN SPRINGS FOR RAILWAY CARRIAGES AND OTHER PURPOSES
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by David Augüste Burr at the Office
of the Commissioners of Patents, with his Petition, on the 30th January
1864. A communication from abroad by Richard Vose, of New York,
State of New York, United States of America.
I, DAVID AUGUSTE BURR, of Washington City, United States of America,
now of No. 12, Southampton Buildings, Chancery Lane, in the County of
Middlesex, Civil Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SPRINGS FOR RAILWAY CARRIAGES AND OTHER PURPOSES,"
a communication, to be as follows:-
These improvements relate chiefly, first, to the use of peculiar end caps or
heads for the purpose of securing and confining the ends of curved spring
plates in the construction of springs.
Second, to the combination of one or more tension plates, with two or more
bearing plates, in such relative positions that the bearing and tension plates
shall respectively yield or spring under the influence of pressure in planes at
right angles to each other.
And, third, to the interposition of a packing of india-rubber, gutter percha,
wool, felt, or other elastic, gummy, or fibrous material between the ends of the
elastic plates, forming an elliptic-spring.
The end caps are made hollow or open from end to end, are rectangular or

page_text: oblate in their transverse section, and are provided with exterior pockets or
recesses which receive the ends of the upper and lower bearing plates. The
ends of the interposed tension plates, which complete the spring pass within
and through these hollow caps, and are bent back sufficiently to embrace the
outer edges thereof. By this arrangement the elasticity of the tension plates
serves to hold the caps securely against the ends of the bearing plates, and the
extension of the latter by compression causes a corresponding extension of the
former.
By the use of these hollow end caps in confining the ends of the elastic
plates or blades of the spring, the interposed tension plate or plates may be
combined with the bearing plates in such a manner as to play or vibrate in a
plane, either coincident therewith or at right angles thereto, and if arranged
in pairs may be placed either with their concave surfaces opposite forming an
ellipse, or vice versa.
The solid head pieces, which may be substituted for the hollow end caps just
described, are made of flat plates, whose thickness is at least equal to the
width of the tension plates to be secured thereby, and which are cut so as to
present longitudinally a circular, semicircular, oblate, or otherwise rounded
section. The upper and lower flat faces of these head pieces may be fitted
with metallic buttons, and the ends of the elastic bearing plates to be confined
thereby are slitted so as to pass under the heads of these buttons and embrace
their shanks. The ends of the two elastic tension plates to combined with
the bearing plates are each bent around the rounded edges of the head pieces,
so as to meet and overlap exteriorly thereon, and are perforated so as to hook
upon a pin or lug which is secured in the outer edge of the head piece for
this purpose. Instead of two distinct tension plates, a single elastic band or
plate of metal twice the length of one of them may be used by bending and
fastening it around the edge of one of the head pieces, and securing its ends
upon the other as above described.
Springs formed in either of the above-mentioned ways may be strengthened
by interposing additional springs, either of metal or rubber between the
bearing or the tension plates thereof. By these improved springs much greater
strength and resilient power can be obtained in a small compass, and with
greater economy of material and labor than in the usual forms of elliptic springs,
whilst the peculiarity of their arrangement and construction admits of the
ready removal and replacement of any one part thereof which may be worn or
damaged, without affecting the remaining portions of the spring.
In packing the ends of elliptic springs caps are pivoted by means of
suitable ears upon their base to the ends of the bearing plates, which are so
د

page_text: turned over as to form eyes to receive the pivot pins; these caps embrace
firmly either end of blocks of rubber, felt, or other elastic, gummy, or fibrous
material thus interposed between the spring plates. Elliptic springs, whose
ends are packed by an interposed elastic or fibrous material, may also be
pivoted centrally in their upper and lower bearings.