Improvements in Ankle Joints for Artificial Feet.
Year: 1898

page_text: Date of Application, 13th Apr., 1898-Accepted, 23rd July, 1898
COMPLETE SPECIFICATION.
Improvements in Ankle Joints for Artificial Feet.
We, ALBERT CARSON WRIGHT, Tinner, and CLAYTON ASHLEY STUBBINS, Clerk,
both of Britt, in the County of Hancock, and State of Iowa, United States of
America, 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 an improvement in artificial limbs, and more particu-
larly to an improved ankle joint for use thereon, our oùject being to provide a
simple, light and inexpensive construction which shall have great ease and at the
same time efficiently hold the foot in the desired position.. To this end the inven-
tion relates to the various matters hereinafter described and claimed.
In the accompanying drawings,
Figure 1 is a longitudinal sectional elevation;
Figure 2 is a transverse sectional elevation on the line 2-2 of Fig. 1;
Figure 3 is a detail of the convex plate; and
Figure 4 is a detail of the lower member of the joint.
Referring now more particularly to these drawings, A represents a portion of
a leg including the ankle, B a foot, and C the present ankle joint. The bottom
of the leg portion A is convex as at a and fits a corresponding concave portion b
toward the rear of the foot B. In this rear portion of the foot is provided an
opening or chamber 61 which, at a convenient distance below the top of the
opening, is provided with a shoulder b². A channel 63 leading from the opening 61
extends into the foot toward the instep.
The joint, properly speaking, comprises a lower member secured to the foot
and an upper member secured upon the leg. The lower member is composed of
a band c of metal or other suitable material of a general elliptical shape to conform
to the contour of the inner wall of the opening b¹ in the foot, this band resting
upon the shoulder 62. In order to ensure ease, this shoulder is preferably padded
as at 64 below the band c. Suitable stay rods c¹ secured to the band by means
of eyes c² or in any other convenient manner, enter the openings 65 through the
foot and are fastened in place, thus firmly securing the band. In the present
instance the free ends of the stay rods are threaded as at 3, and are engaged by
nuts which enter the openings 66 from the under side of the foot. The band c
is concave to conform to the shape of the opening in the foot. Extending length-
wise of the lower member, i.e., in the direction corresponding with the length of
the foot, is a concave cross piece attached at its ends to the band, this cross-
piece being provided with a V-shaped channel c6.
The upper member of the joint comprises a convex plate c', which is secured
upon the bottom of the leg by means of screws or other suitable members, and is
provided with a ball race. This plate fits upon the lower member of the joint
and has suitable movement thereon. A strap upon the lower side of the plate
embraces the cross-piece upon the lower member, thus holding the two parts of
the joint together, and at the same time permitting the plate and cross-piece to

page_text: roll forwardly and backwardly upon suitable balls placed in the channel co. The
strap is curved in its body portion and a slight rock therefor afforded.
An arm also extends downwardly from the strap and is provided with an
eye co. A coiled spring c¹² attached at one end to the eye c¹0 in the arm, enters
the chamber formed in the foot and lies in the recess extending toward the instep,
the forward end of this spring being held by a screw or other suitable member c¹³.
In the groove of the cross piece upon the lower plate are placed the balls c¹, which
afford a roller bearing between the two members of the joint.
It is thought that the operation of this joint will now be apparent. The back-
ward and forward movement between the two members afforded by the strap
upon the top plate and the bending of the foot with relation to the leg in the
movement of walking, affords a movement similar to that incident to the use of
a natural ankle, and has been found of great ease and comfort to the wearer.
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. In an artificial limb, the combination with a foot section and a leg section,
a concave plate secured to the foot section, and a convex plate secured to the leg
section, halls interposed between said plate, a strap secured to the plate of the leg
section and embracing the plate of the foot section, an arm secured to the strap,
and a spring having one end secured to the arm and the other end secured to the
foot section, substantially as set forth.
2. In an artificial limb, the combination with a foot section and a leg section,
a concave plate secured to the foot section, and a convex plate secured to the leg
section, said plates being provided with grooves, balls arranged in said grooves,
a strap secured to the plate of the leg section, an arm secured to the strap, and a
spring having one end secured to the arm and the other end secured to the foot
section, substantially as set forth.
3. In an artificial limb, the combination with a foot section and a leg section,
said foot section provided with a chamber communicating with a longitudinal
horizontal channel, said chamber being provided with an offset or shoulder, a
convex plate secured to the leg section and provided with a groove, a concave
plate having a depending band or collar located within the chamber and seated
upon the shoulder, and provided with a groove, balls arranged in said groove, a
band secured to the convex plate and embracing the concave plate, an arm
secured to the band, and a coiled spring, one end of which is connected to the
free end of the arm and has its other end projecting into the longitudinal channel
and secured therein, substantially as set forth.
Dated this 19th dow of Ini 1808
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.