Improvements in Extension Feet.
Year: 1896

page_text: Date of Application, 4th Feb., 1896-Accepted, 6th Juna, 1896
[Communicated from abroad by EDWARD LOUIS O'CONNOR, of 1425 Michigan
Avenue, Chicago, Illinois, United States of America, Manufacturer.]
Improvements in Extension Feet.
We, LILLEY AND SKINNER LIMITED, of Paddington Green, W., Boot
Manufacturers, and WILLIAM GIRARD DELL, and PERCY JOHN MOORE
GUNTHORP, both of 2 Bloomsbury Street, W.C. Surgical Appliance Makers, trading
together in partnership as The O'Connor Extension Co., of 2 Bloomsbury Street,
all in the County of London, 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 :-
This invention relates to extension feet for use by persons having one short leg,
with a view to the lengthening. of the leg to correspond with the sound one, and
to give a symmetrical foot upon which an ordinary shoe that will mate with one
applicable to the sound foot may be worn.
In the Specification of a prior Patent No. 12144 of 1890 an attempt was mado
at the results here aimed at; but with only partial satisfaction. The improvements
herein described have resulted in complete success.
By reference to the above mentioned Patent, it will be observed that the upper
surface of the false structure upon which the bottom of the natural foot bears is
generally inclined from top to bottom, though the inclinations of different portions
of this surface vary in degree. In that construction a rigid instep piece is applied
to the base of the false structure beneath which instep piece the toes of the natural
foot extend, but in practice it has been found that the inclination of the surface
npon which the natural foot bears permits a sliding movement of the foot down
such surfaces, and in consequence, a compression of the toes beneath the rigid false
instep is so uncomfortable that in many cases this instep has been of necessity
abandoned. In the absence of such false instep it is impossible to use a low shoe,
or, indeed, any shoe that matches that upon the sound foot of the wearer, while any
enlargement or modification of the shape of the false instep to give room for the
toes, thus crowded beneath it, destroys the correspondence between the artificial
and natural foot of the wearer. Whether this instep piece be employed or not,
the slipping forward of the foot upon the extension or false structure is highly
objectionable for obvious reasons.
By the present invention, in so far as it relates to a change in the contour of the
surfaces upon which the natural foot bears, we have provided for the retraction of
the toes and have guarded against the forward slipping movement of the wearer's
foot upon said surfaces of the extension, with the two-fold result of preventing
wedging action of the foot within its enclosure and securing freedom of the toes.
beneath the false instep, if employed.
Another difficulty experienced in the use of the structure shown in said prior
Patent relates to the heel piece which rises from the false structure or extension
back of and around the sides of the heel of the wearer. This heel piece in said
prior Patent is a continuous rigid plate, entirely covering and embracing the rear
and sides of the heel proper of the wearer. The objections to this feature of the
former construction (hereinafter specified) are obviated by the skeleton heel piece.
herein shown and described.

page_text: Now, turning to the drawings, which illustrate our present invention:
Figure 1 illustrates the false foot or extension in side elevation, the heel thereof
being elevated from the floor as it will be when a shoe having a suitable heel is
applied thereto.
Figure 2 is a side elevation of the base of the extension foot with a false instep
and my improved heel-piece applied thereto, but without the covering or upper.
Figure 3 is a transverse vertical section in the line 3-3 of Figure 2, looking to
the rear.
Figure 4 is a side elevation of the extension with the lame foot resting upon the
base thereof, the leather upper or other covering for the attachment of the extension
foot to the foot of the wearer being indicated in dotted lines.
Figure 5 illustrates the false structure applied to the foot of the wearer and
having thereon a low shoe which mates the shoe worn upon the sound foot of the
wearer.
A in Figure 2 represents the base piece of our improved extension foot.
B represents the improved heel piece and C the instep piece of said prior Patent.
D, in Figure 1, represents the leather or other covering of the base piece
extended above the heel piece B and about the foot and ankle of the wearer,
and as being laced in front to confine the wearer's foot in its place on the false
structure.
The upper surfaces of the base A, upon which the bottom of the foot of the
wearer bears, are; for this description, divided into thrée portions, to wit: the
elevated portion a upon which the heel of the wearer rests, the lower portion a¹
upon which the ball and toes of the wearer bear, and the intermediate portion a
which is opposite the hollow and the rear ball portion of the wearer's foot. The
portions a a are made more nearly horizontal than in the said prior Patent, while
the intermediate portion a' is substantially, and preferably, quite vertical. The
effect of making the portions a a', and especially the heel portion a; nearly or
substantially horizontal, as shown, is to prevent a tendency of the foot of the
wearer to slip forward upon the base, and to enable it to be retained against such
slipping movement by the laced upper D without wedging action or serious pressure
of the wearer's foot against the laced or front portion of the upper. The vertical
arrangement of the surface a' gives a more effective supporting bearing to the ball
of the foot of the wearer upon the base A, while at the same time, the ball has a
more retracted position upon the said base, so that if au instep piece C be employed
the toes find freer space and greater comfort beneath it. By reason of this
improvement we have found that we may select a pair of shoes from any ordinary
stock, of which pair one will fit the sound foot and may apply the other to the
extension foot without the least discomfort, and, of course, with the result of
presenting two clothed feet to view which correspond as 'perfectly as the shoes
upon the two sound feet of any person. This has heretofore been impractical in
a majority of cases, and the advantage set forth is obtained by the change above
indicated in the direction of the several surfaces a a' a', -as shown in the
accompanying drawings.
On presenting this improved extension foot to surgeons and others for
examination, it has been urged that it is impossible for the natural foot to conform
to the changed surfaces a a' a' upon which it is to bear, by reason of the verticality
of the surface a, but from actual use, we have 'demonstrated to these and to all
objectors that the form of surfaces here illustrated are entirely practical, and that
the foot will, in the course of a few week's time, readily adapt itself to such surfaces
with perfect comfort.
Another advantage resulting from the new arrangement of the surfaces 'a a a³,
and due inore largely to the making of the surfaces a and a more uearly hori-
zontal, is that when the foot is clothed with a shoe corresponding with that upon
the sound foot of the wearer, the wearer may stand with the extension foot squarely
and firmly in bearing upon the floor while his leg is perfectly straight.. This also was
impossible or very difficult in the use of the said former construction. It was usually

page_text: necessary for the wearer, in standing, to bend the knee joint of the shortened limb
forwardly in order to bring the sole of the shoe worn upon the extension squarely
upon the floor. The substantially horizontal direction of the surface a gives such a
firm supporting bearing of the heel of the wearer upon the extension that the
straightening of his leg involves no appreciable tendency to push the foot forward
upon said surface, and he therefore naturally straightens the shortened leg as he
does the sound one, in either standing or walking.
In the said prior construction, the heel piece applied to the base A was, as already
stated, continuous and surrounding the heel of the wearer from the surface of the
base a upwardly to, or nearly to, the ankle joint. When made of ordinary metal
this involves rapid destruction of the lining of the upper, due to the perspiration of
the foot, and when made of aluminum with a view of avoidance of rust, it
involved the rotting and disintegration of the metal itself. Inasmuch as these
extension structures are necessarily expensive, both in their original construction
and in their repair, we have successfully sought to obviate the objection last above
pointed out by making the heel piece of open or skeleton form, as shown. In this
construction of the said heel piece bb are two rigid upright side bars, and b' is a
yoke having its extremities secured to the upper ends of the side bars b, and curved
to reach around the back of the foot just above the heel and below the ankle joint,
as shown.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In an extension foot intended for application to the foot of a shortened
leg, a base having a nearly horizontal surface upon which the heel of the natural
foot is to rest, a nearly horizontal surface on which the ball of the foot is to
bear, and an intermediate, substantially vertical surface opposite the hollow of the
foot.
2. In an extension foot for application to the natural foot of a shorter leg, the
combination with a base having an elevated surface upon which the heel of the
natural foot is to rest, and a lower surface upon which the ball of said natural foot
is to bear, of a heel piece consisting of two side uprights and a rearwardly curved
yoke, substantially as described.
3. In an extension foot for application to the natural foot of a shorter leg, the
combination of a base having a nearly horizontal elevated surface upon which the
heel of the natural foot is to bear, a nearly horizontal surface to receive the ball
and toes of the natural foot, and an intermediate and substantially vertical surface
opposite the hollow of the foot, of an open heel piece consisting of two lateral
uprights, and a rearwardly curved yoke which embraces the rear part of the
ankle.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicants.