IMPROVEMENTS IN SPRINGS FOR LOCOMOTIVE ENGINES, RAILWAY CARRIAGES, AND WAGONS, THE SAID IM- PROVEMENTS BEING ALSO APPLICABLE TO SPRINGS USED FOR OTHER PURPOSES
Year: 1878

page_text: LETTERS PATENT to Samuel Dobson Davison, of Leith, in the County of
Mid Lothian, North Britain, for the Invention of "IMPROVEMENTS IN SPRINGS
FOR LOCOMOTIVE ENGINES, RAILWAY CARRIAGES, AND WAGONS, THE SAID IM-
PROVEMENTS BEING ALSO APPLICABLE TO SPRINGS USED FOR OTHER PURPOSES."
A communication from abroad by Edward Spaulding, of the City of Brooklyn,
in the State of New York. in the United States of America.
PROVISIONAL SPECIFICATION left by the said Samuel Dobson Davison at
the Office of the Commissioners of Patents on the 30th August 1878.
SAMUEL DOBSON DAVISON, of Leith, in the County of Mid Lothian, North Britain,
"IMPROVEMENTS IN SPRINGS FOR LOCOMOTIVE ENGINES, RAILWAY CARRIAGES, AND
WAGONS, THE SAID IMPROVEMENTS BEING ALSO APPLICABLE TO SPRINGS USED FOR
OTHER PURPOSES." [A communication from abroad by Edward Spaulding, of the
City of Brooklyn, in the State of New York, in the United States of America.]
This Invention, which relates to improvements in the construction of springs for
locomotive engines, railway carriages, and wagons, and which are also applicable for
other purposes, has for its objects the production of a spring with the least weight
of metal, combined with the greatest sustaining power, and a maximum of
elasticity.
According to this Invention, in lieu of constructing springs of flat plates of steel,
as has been done hitherto, plates curved or concaved in the direction of their cross
sections are used, so that the said plates will have a form in transverse section
similar to a segment of a tube split lengthwise, and so that when power is applied
the strain of tension is exerted on the convexity, and the crushing force on the edge
of the plate, thereby the liability of a fracture starting on the edge of the spring is
avoided by virtue of the edge tending to close up should a fracture occur.

page_text: In a compound spring, consisting of several layers of plates, and constructed
according to this Invention, the different layers of plates retain their position one
above the other by virtue of the convexity of the one filling into the concavity of
the other plate, whereby great firmness and solidity is obtained, and the use of
slots and studs, such as have been used hitherto in the construction of springs, is
avoided.
When successive layers of plates or leaves are required, the edges of the plates
are preferably made somewhat thinner than their centre, so that the said plates
may fit well one upon the other, and enable the spring to have an uniform
movement.
The curve or convexity in the cross section, which has been found to give the
best general results for all widths of steel, is that which is an arc of the circle
which the lincal width of the plate would describe as a radius.
In practice, the several curves, both in the cross section and in the longitudinal
curves, straighten out with uniformity, so that the several parallel leaves will
always remain in close contact with one another.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Samuel Dobson Davison in the Great Seal Patent Office on the 11th
March 1879.
SAMUEL DOBSON DAVISON, of Leith, in the County of Mid Lothian, North Britain.
"IMPROVEMENTS IN SPRINGS FOR LOCOMOTIVE ENGINES, RAILWAY CARRIAGES, AND
WAGONS, THE SAID IMPROVEMENTS BEING ALSO APPLICABLE TO SPRINGS USED FOR
OTHER PURPOSES." A communication from abroad by Edward Spaulding, of the
City of Brooklyn, in the State of New York, in the United States of America.
This Invention relates to improvements in the construction of springs for
locomotive engines, railway carriages, and wagons, the said improvements being
also applicable to springs used for other purposes, and the said Invention has for its
objects the production of a spring in which a minimum weight of metal is combined
with a maximum of sustaining power and elasticity.
According to the said Invention, in lieu of constructing springs of flat plates of
steel, as has been done hitherto, the said springs are formed of a plate, or of several
plates or leaves which is, or all of which are curved or concaved in the direction of
their transverse section, so that the said plates have in transverse section a form
similar to a segment of a tube split lengthwise, and so that when power is applied
.the strain of tension is exerted on the convexity, that is to say, the mid-part of the
width of the plate or plates, and the crushing force at the edges or outer portion of
the width of the plate or plates.
Figure 1 of the accompanying Drawing illustrates in side elevation, and Figure 2,
in transverse section on the line 1, 2, Figure 1, a spring constructed according to
this Invention of several plates or leaves.
By reference to these Figures, the construction of the springs according to the
said Invention will be readily seen, it being understood that the spring may consist
of one or other number of plates, according to special requirements.
The curve or convexity of the said plates in their transverse section, which has
been found to give the best general results for all sections of steel, is that which is
an arc of the circle which would be described with a radius equal to the lineal
width of the plate..
When power is applied to a spring constructed according to this Invention, the
strain of tension is exerted on the convexity, and the crushing power on the edge
of the plate, and thereby the liability of a fracture starting at the edge of the spring
is avoided by reason of the edge inclining to close up should tendency to such a
fracture occur.
In compound springs constructed according to this Invention, that is to say,
springs consisting of several plates or layers, the different plates or layers retain
their relative position by reason of the convexity of the one plate or layer fitting
into the concavity of the other plate or layer, which gives to the spring greater.
firmness and solidity, and slots and studs, such as have been used hitherto in the
construction of springs, may be dispensed with.
In compound springs, the edges of the plates or layers are preferably made
somewhat thinner than their centre or mid-thickness, so that the said plates may
fit well one upon the other, and allow the spring. to have uniform movement in its
parts. The plates or leaves, whether of simple or compound springs, may also be
made tapering at their ends.
When the springs constructed according to my Invention are in use, the several
curves, both in those of the transverse section and in the longitudinal curves,
straighten out with uniformity, so that the several plates or leaves will always
remain in close contact with one another.
In some cases, as, for instance, in carriage springs, the plate or plates, or leaves,
may be constructed or formed of a varying curvature in their transverse section,
and may be flattened towards the ends of the spring.

page_text: Having now described and particularly ascertained the nature of the said
Invention, and the system, mode, or manner in or under which the same is or may
be used or practically carried into effect, I would observe in conclusion that what
I consider to be novel and original, and therefore claim as the Invention secured
to me by the herein-before in part recited Letters Patent is, the improved spring,
constructed or formed essentially as herein-before described and illustrated, that is
to say, a spring consisting of a plate, or, of plates, or leaves, whose transverse section
is curved, or of the figure which would be presented by the transverse section of a
portion of a tube split longitudinally therefrom, the said spring being constructed
so that when power is applied the strain of tension is exerted on the convexity and
the crushing force at the edges, as before described in compound springs, the
several plates or leaves being all of this said form and position.
In witness whereof, I, the said Samuel Dobson Davison, have hereunto set
my hand and seal, this Sixth day of March, in the year of our Lord One
thousand eight hundred and seventy-nine.
SAMUEL DOBSON DAVISON. (L.S.)