IMPROVEMENTS IN HELICAL SPRINGS
Year: 1881

page_text: LETTERS PATENT to Louis Sterne, of No. 9, Victoria Chambers, Westminster,
in the County of Middlesex, Engineer, for an Invention of " IMPROVEMENTS
IN HELICAL SPRINGS."
PROVISIONAL SPECIFICATION left by the said Louis Sterne at the Office of
the Commissioners of Patents on the 18th March 1881.
LOUIS STERNE, of No. 9, Victoria Chambers, Westminster, in the County of
Middlesex, Engineer. "IMPROVEMENTS IN HELICAL SPRINGS."
My Invention relates to a construction of helical springs, whereby I am enabled
to reduce the size and weight of spring_necessary to provide a given elastic range
for a given pressure. For this purpose I make the spring of stoel bar having a
section somewhat like the letter Z, that is to say, a deep and thin middle body
with lips or beads projecting at its upper and lower extremities respectively in
opposite directions, the section thus corresponding with that of a flanged girder, the
metal being so disposed as to give great strength. In coiling this bar into a helix
I cause its middle body to take a position inclined to the axis of the helix, each
convolution being thus made to present a conical form so that each can overlap the
next in order. In consequence of this overlapping (which is limited only by the
lips or beads of the successive convolutions coming in contact with each other) the
spring can be compressed through a considerable range, each of its convolutions
being nevertheless of such depth and form as to give great stiffness. In coiling a
spring such as I have described, I find it of advantage to perform the operation in
several stages, each giving an increased amount of curvature to the bar until its
final curvature is reached, annealing or softening the steel when necessary between
the successive stages.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Louis Sterne in the Great Seal Patent Office on the
12th September 1881.
LOUIS STERNE, of No. 9, Victoria Chambers, Westminster, in the County of
Middlesex, Engineer. "IMPROVEMENTS IN HELICAL SPRINGS."
My Invention relates to a construction of helical springs, whereby I am enabled
to reduce the size and weight of spring necessary to provide a given elastic range
for a given pressure. For this purpose I make the spring of steel bar having a
section somewhat like the letter Z, that is to say, a deep and thin middle body
with lips or beads projecting at its upper and lower extremities respectively in
opposite directions, the section thus corresponding with that of a flanged girder, the
metal being so disposed as to give great strength. In coiling this bar into a helix
I cause its middle body to take a position inclined to the axis of the helix, each
convolution being thus made to present a conical form so that each can overlap the
next in order. In consequence of this overlapping (which is limited only by the
lips or beads of the successive convolutions coming in contact with each other) the
spring can be compressed through a considerable range, each of its convolutions
being nevertheless of such depth and form as to give great stiffness. In coiling a
spring such as I have described, I find it of advantage to perform the operation in
several stages, each giving an increased amount of curvature to the bar until its
final curvature is reached, annealing or softening the steel when necessary between
the successive stages.
The accompanying Drawings shew a spring according to my Invention. Fig. 1
is a vertical section; Fig. 2, a side view; and Figs. 3 and 4 are plans looking
from above and from below respectively. The bar A of which the spring is made
has a thin and deep middle body, having at its one edge a lip or bead B projecting
outwards, and at its other edge a lip or bead C projecting inwards. The bar is
coiled, as shewn, in an inclined attitude, so that each convolution presents a conical
form overlapping the next convolution in order. When the spring is fully
compressed each convolution at both its edges butts against the beads of the next
convolution, the conical exterior of the one convolution fitting but not so tightly as
to jam into the conical interior of the other.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim,―
The construction of helical spring formed by coiling in an inclined attitude a
thin deep bar made with opposite beads or lips at its edges, substantially as herein
described.
In witness whereof, I, the said Louis Sterne, have hereunto set my hand and
Ant in the
Land One thousand