Improvements in Artificial Feet.
Year: 1895

page_text: Date of Application, 17th Sept., 1895-Accepted, 26th Oct., 1895
Improvements in Artificial Feet.
WILLIAM LINCOLN MARKS, of
We, GEORGE EDWIN MARKS and
701 Broadway, in the City of New York, in the County and State of New York,
United States of America, Manufacturers, do hereby declare the nature of this
invention, and in what manner the same is to be performed, to be particularly
described and ascertained, in and by the following statement :-
of a
The invention relates to improvements in artificial feet, and consists in a
member composed of an inelastic core, an elastic or rubber portion in the outline
foot and enclosing said core, and a spring or series of springs embedded in the
rubber below said core and extending lengthwise of the foot, as hereinafter more
fully explained.
The
The object of the invention is to produce an artificial foot which shall be efficient
and durable, capable of convenient use by the wearer and possess actions when
under heel or toe pressure, as during the act of walking, which greatly enhance
the value of the foot and facilitate its use by and add comfort to the wearer.
spring embedded in the rubber portion of the foot is wholly inactive when the
foot is at rest, being at such time simply held in an unflexed condition in the
rubber. The spring will preferably be composed of a series of parallel wires
covered with canvas and separated from one another by lines of stitching which
will form parallel pockets in the canvas, and said spring in its edge outline will
conform substantially to the horizontal sectional outline of the foot. The presence
of the spring will increase the durability and resiliency of the foot and impart
certain qualities thereto which will render the same comfortable to the wearer and
natural and graceful in action. The foot may be made of sponge rubber for
softness, lightness, noiselessness and comfort and the spring, being inactive 'when
the foot is at rest, will not detract from any of the good qualities of the foot but
will tend to preserve the correct shape of same, impart a degree of stiffness on
horizontal lines and ensure the desired resiliency under heel and toe pressure.
A further feature of the invention consists in the provision of an air space or
cell in the heel portion of the rubber below the inelastic core, for the purpose of
lightening the foot, increasing the spring action therein on proper lines and
facilitating the ankle motions.
The invention will be more readily understood by reference to the accompanying
drawings, in which :-
Figure 1 is a central vertical longitudinal section of a foot constructed in
5 accordance with and embodying the invention, the dotted lines indicating the
position of the foot when under toe pressure;
Figure 2 is a bottom view of same, and
Figure 3 is a detached plan view of the spring located in the rubber portion
of the foot, a portion of the canvas being removed to expose the individual wires.
In the accompanying drawings, A indicates the foot, B the inelastic core; C the
elastic or rubber portion of the foot enclosing said core; D the spring which is
embedded in the rubber portion of the foot and extends lengthwise of same below
the core B, and' E the air space or cell in the heel portion of the rubber below the

page_text: said core.
The spring D will by preference conform substantially in outline with
the horizontal outline of the foot and be composed of the series of wires a held in
pockets formed in the canvas covering b, as illustrated more fully in Figure 3.
The elastic portion C of the foot will preferably be composed of sponge rubber,
and the spring D will be moulded into the rubber at about an equal distance
between the bottom of the foot and the lower portion of the inelastic core B, the
Baid spring extending lengthwise of the foot from the heel to the toe portion
thereof. The spring D is wholly inactive while the foot is at rest and comes into
action only during the use of the foot, as in the act of walking, and at this time
whether the pressure is exerted against the toe or the heel of the foot, the
spring D will operate in a natural, easy, comfortable manner to restore the foot to
its initial position and condition, the force of the spring lessening as the foot
regains its normal position. The spring D when arranged as shown imparts
sufficient rigidity to the foot to enable the same to retain its shape and consistency
without rendering the same awkward in use or uncomfortable to the wearer.
We
prefer to employ sponge rubber for the main portion of the foot in view of its
lightness, flexibility and yielding nature and when sponge rubber is thus employed,
the spring will increase the durability and elasticity of the same without
destroying any of the other good qualities resulting from the use of the sponge
rubber.
.
We do not confine the invention to any particular form or extent of spring D but
we prefer to construct the same of the series of wires a secured within the canvas b,
the whole forming a broad strip extending transversely through the center of the
lower portion of the foot from the heel to the toe portion thereof, the front end of
the strip composing the spring D being conformed to the general outline of the toe
portion of the foot in order that the latter may have a natural movement and the
strain equally distributed through the saine. The spring D acts throughout its
entire length during the use of the foot, being free to yield with the rubber, and not
only operates by direct action to restore the flexed portion of the foot to its normal
position but also indirectly by combining with the yielding rubber to create a
longitudinal drawing action to aid in restoring the foot to a normal condition.
Within the heel portion of the rubber C is formed the air space or cell E, which
serves to lighten the foot, increase the spring action therein on proper lines and
facilitate the ankle motions. The space or cell E is preferably located intermediate
the core B and spring D, where it will facilitate the action of the spring D and also
aid in preventing any jarring effects on the stump of the wearer from the firm
contact of the heel of the foot against the ground.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :
1. The artificial foot consisting of the inelastic core, the rubber or elastic portion
in the outline of the foot and enclosing said core, and the spring embedded in
said rubber portion below the core and extending lengthwise of the foot ;
substantially as set forth.
2. The artificial foot consisting of the inelastic core, the rubber or elastic portion'
in the outline of the foot and enclosing said core, and the spring composed of the
series of wires enclosed in canvas and embedded in said rubber portion below
the core and extending lengthwise of the foot; substantially as set forth.
3. An artificial foot having embedded within its rubber lower portion the
continuous spring extending lengthwise of the foot, substantially as set forth.
4. An artificial foot having embedded within and extending lengthwise of its
rubber lower portion the spring composed of the series of wires covered with
canvas; substantially as set forth.
5. An artificial foot consisting of the inelastic core and the rubber or elastic

page_text: portion in the outline of the foot and enclosing said core, the heel portion of said
rubber having within it the air space or cell; substantially as set forth.
Dated this 24th day of August 1895.
GEORGE EDWIN MARKS.
WILLIAM LINCOLN MARKS.
Haseltine, Lake & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicants.