IMPROVEMENTS IN THE CONSTRUCTION OF ELLIPTIC SPRINGS FOR WHEEL CARRIAGES, AND OTHER PURPOSES
Year: 1862

page_text: LETTERS PATENT to George Tomlinson Bousfield, of Loughborough Park,
Brixton, in the County of Surrey, for the Invention of "IMPROVEMENTS
IN THE CONSTRUCTION OF ELLIPTIC SPRINGS FOR WHEEL CARRIAGES, AND OTHER
PURPOSES." A communication from abroad by Jabez Marshall Wood-
ward, residing at Brooklyn, in the County of Kings, and State of New
York in the United States of America
PROVISIONAL SPECIFICATION left by the said George Tomlinson Bousfield
at the Office of the Commissioners of Patents, with his Petition, on
the 23rd April 1862.
I, GEORGE TOMLINSON BOUSFIELD, of Loughborough Park, Brixton, in
5 the County of Surrey, do hereby declare the nature of the Invention for
"IMPROVEMENTS IN THE CONSTRUCTION OF ELLIPTIC SPRINGS FOR WHEEL CARRIAGES,
AND OTHER PURPOSES," to be as follows:-
The object of this Invention is to obtain a spring that will oppose a
resistance to a superimposed weight, and that possesses great elasticity, with
O a less weight of material than is required in the construction of the ordinary
elliptic springs in general use. In order to accomplish this result the arched
leaves of the spring are according to this Invention combined with an arched
spring tie bar of less curvature than the leaves with which it is combined, by
connecting the ends of the longest leaf of the spring with the ends of the
5 arched tie bar. In a combination of this description the straightening of the

page_text: leaves by transverse pressure tends to straighten the tie bar by drawing it
longitudinally, and as the elasticity of the material tends to cause the tie bar
to regain its arched form, and this tendency increases the more nearly the tie
bar is straightened, being almost equal to the tensile strength of the bar when
the tie bar almost approaches a straight line, the strength of the spring to
resist transverse pressure increases rapidly with its flexure, and a less amount
of material can be employed to form a spring possessing equal strength with
an elliptic spring of the ordinary construction. The adjacent ends of the
leaves and tie bar of a spring are, by preference, combined by means of a
head upon the tie bar, having a shoulder against which the adjacent end of
the longest leaf of the spring abuts. In order when required to connect the
adjacent ends of two tie bars and two sets of leaves, so that the whole shall
form a complete elliptic spring, the adjacent heads of the tie bars against the
shoulders of which the end of the spring leaves abut are held together,
according to this Invention, by means of a clasp, which partially encircles
them. When it is desired to obtain great flexibility in the spring with light
loads combined with great resistance to heavy pressures, so that when the.
springs are applied to wheel carriages the latter will run easily either light or
heavy laden, the spring leaves are, according to this Invention, combined with
the tie bar in such manner that the leaves will yield a certain distance to
pressure before the strain is propagated to the tie bar to extend it longi-
tudinally.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Tomlinson Bousfield in the Great Seal Patent Office
on the 20th October 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
TOMLINSON BOUSFIELD, of Loughborough Park, Brixton, in the County of
Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of April, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said George Tomlinson Bousfield, Her special licence; that I, the said George
Tomlinson Bousfield, my executors, administrators, and assigns, or such others
as I, the said George Tomlinson Bousfield, my executors; administrators, and
assigns, should at any time agree with, and no others, from time to time

page_text: 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 THE CONSTRUCTION OF ELLIPTIC SPRINGS FOR WHEEL.
CARRIAGES, AND OTHER PURPOSES," a communication to me from abroad by the
Inventor, Jabez Marshall Woodward, a person resident at Brooklyn, in the
County of Kings, and State of New York, in the United States of America, upon
the condition (amongst others) that I, the said George Tomlinson Bousfield, my..
executors or administrators, by an instrument in writing under my, 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 George Tomlinson Bousfield; do hereby
declare the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say:-
Figure 1 represents a side view of an elliptic spring constructed according
to the principle of the Invention, one washer and bolt at the end being
removed to show the mode of connecting the tie bars and spring leaves;
Figure 2 represents a top view of the same; and Figure 3 represents a side
view of a half elliptic spring constructed upon this principle.
The object of this Invention is to obtain a spring that will oppose a
resistance to a superimposed weight, and that possesses great elasticity with a
less weight of material than is required in the construction of the ordinary
elliptic springs in general use. In order to accomplish this result the arched.
leaves of the spring are, according to this Invention, combined with an arched-
spring tie bar of less curvature than the leaves with which it is combined by
connecting the ends of the longest leaf of the spring with: the ends of the
arched tie bar. In a combination of this description the straightening of
the leaves by transverse pressure tends to straighten the tie bar by drawing it
longitudinally, and as the elasticity of the material tends to cause the tie bar
to regain its arched form, and this tendency increases the more nearly. the tié
bar is straightened, being almost equal to the tensile strength of the bar when
the tie bar almost approaches a straight line, the strength of the spring to.
resist transverse pressure increases rapidly with its flexure, and a less amount
of material can be employed to form a spring possessing equal strength with
an elliptic spring of the ordinary construction..

page_text: The second part of the Invention has reference to the mode of connecting
the adjacent ends of the leaves and tie bar: of a spring, and consists in com-
bining the two by means of a head upon the tie bar having a shoulder, against
which the adjacent end of the longest leaf of the spring abuts.
The third part of the Invention has reference to the mode of connecting the
adjacent ends of two tie bars and two sets of leaves, so that the whole-forms' a
complete elliptic spring. This part of the Invention consists in combining the
adjacent heads of the tie bars, against the shoulders of which the ends of the
spring leaves abut by means of a clasp, which partially encircles the adjacent
heads of the bars.
:
The object of the fourth part of the Invention is to obtain great flexibility
in the spring with light loads, combined with great resistance to heavy-pres-.
sures, so that when the springs are applied to wheel carriages the latter will
run easily either light or heavy laden. To this end this part of the Invention
consists in combining the spring leaves with the tie bar in such manner that
the leaves will yield a certain distance to pressure before the strain is propa-
gated to the tie bar to extend it longitudinally.
The first part of the Invention may be used without the second, third, and
fourth parts, by employing some substantially different means of connecting
the spring leaves and arched tie bar; the first and second parts of the Inven-
tion may also be used without the third and fourth parts; the fourth part of
the Invention may or may not be used as deemed expedient.
The spring represented by Figures 1 and 2 in the accompanying Drawing,
embodies all parts of the Invention; that represented by Figure 3 embodies
the first and second parts of the Invention. These Drawings are on a scale of
one-third the actual sizes of the springs. The full elliptic spring represented
at Figures 1 and 2 has two sets of arched spring leaves A, A, the members of
each set being connected together by means of a square clasp B at their longi-
tudinal centres. The tie bar. C for each set of leaves is arched, its curvature
being less than that of the adjacent. leaf, so that the two can touch only at
their ends, there being a free space m'at their centres, so that the transverse.
pressure upon the centre of the spring leaves is not propagated directly to the
centre of the tie bar. The ends of each tie bar C are formed into heads e,
with shoulders i, against which the adjacent ends of the longest leaf of the
adjacent set abuts, the shoulders being recessed, as shown in the Drawing, so
as to overlap the leaf and prevent its escape. In order to combine the two
sets of leaves and tie bars into one spring, the peripheries of the heads of the
tie bars are rounded, and are encircled by a clasp n, having .the form of a
slotted cylinder; and in order to prevent the tie bars, leaves, and clasp from.

page_text: moving laterally upon each other, a washer h is applied to each side of the
head, and the two washers are connected by a screw bolt or rivet s, whose
shank passes through a hole half of which is formed in each head of each tie
bar. In order to embody the fourth part of the Invention, the distance
between the opposite shoulders of each tie bar is made longer than the lowest
arched spring leaf, so that a space is left between the end of the spring. leaf
and the adjacent shoulder of the tie bar, as shown at Figure 1. This space
permits the spring leaves to slide along upon the tie bar upon the first appli-
cation of force to their centres without propagating the strain to the tie bar,
hence the spring resists the pressure by the elasticity of its leaves alone until
the ends of the latter come in contact with the shoulders of the tie bars, and
as the spring leaves when released from the tie bar are much less rigid than
when the two act in concert, the spring is as easily flexed by a light weight at
the commencement as it is subsequently by a heavy weight..
When constructing a half elliptic spring, such as is represented at Figure 3,'
the heads e of the tie bar are quilled, so as to form holes through which the
bolts are inserted, by which the ends of the spring are connected to the
adjacent parts of the wheel carriage or other machine to which the spring is
applied.
When a spring is exposed to great and sudden changes of pressure, as is
sometimes the case in wheel carriages running upon rough roads, there is a
tendency of the spring leaves to jump from the shoulders of the tie bar, in
such cases I quill the end of the longest spring leaf as well as the end of the
tie bar, making the opening in the latter large enough to receive the exterior
of the former, as shown in Figure 4, so that the same bolt secures both; or I
quill or thicken the ends of the longest spring leaves so as to form heads,
which are retained by the clasp, as shewn at Figure 5. It is found convenient
to employ two tie bars with a full elliptic spring, such as is represented at
Figure 1, but a single arched tie bar of greater strength may be used in place
of two, its beads being fitted with double shoulders, one at each side, so that
the same head forms the abutment of both sets of spring leaves. The leaves
and tie bars are all made of tempered steel. The number of the spring leaves
may be increased or diminished, as found expedient.
Upon an examination of Figure 1 it will be seen that a force applied to
compress the spring transversely to its length is propagated through the spring
leaves to the ends of the tie bars, and tends to extend these last in the
direction of their length. This tendency is opposed by the elastic force of the
material of which the tie bar is formed, which tends to maintain its arched
form; and as the resistance of the tie bar to straightening by drawing its ends

page_text: apart increases in an increasing ratio the nearer it approaches a straight line,
the resistance of the spring to flexure by the pressure of a transverse force
applied at the centres of its spring leaves augments in an increasing ratio, and
in practice it is found almost impracticable to flex the spring sufficiently. to
straighten the tie bar.
. What I claim as the Invention and desire to secure by Letters Patent is,
the combination of the arched leaves of a spring with an arched tie bar.
substantially as herein set forth.
I also claim the combination of the arched spring leaves and arched tie bars
by means of a head on the tie bar against whose shoulder the end of the
adjacent spring leaf abuts, substantially as herein set forth.
I also claim the combination of two sets of spring leaves and two tie bars
by means of a clasp embracing the adjacent heads of the tie bars, substantially
as herein set forth.
I also claim the combination of the spring tie bar and spring leaves in such
manner that the spring leaves may be flexed a certain distance before the
pressure is propagated to the tie bar to extend it longitudinally, substantially
as herein set forth.
In witness whereof, I, the said George Tomlinson Bousfield, have
hereunto set my hand and seal, this Ninth day of October, in the
year of our Lord One thousand eight hundred and sixty-two.
GEO. T. BOUSFIELD.
L.S.)