US2530286A

US2530286A - Foot control for artificial legs

Info

Publication number: US2530286A
Application number: US4856A
Authority: US
Inventors: John G Catranis
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-01-28
Filing date: 1948-01-28
Publication date: 1950-11-14
Anticipated expiration: 1967-11-14

Description

1950 J. G. CATRANIS 2,530,286

FOOT CONTROL FOR ARTIFICIAL LEGS Filed Jan. 28, 1948 2 Sheets-Sheet 1 Jill-2:1- jl: E

1 I 1 45 39 40 43 INVENTORZ 3a (701 Cafra ns,

Patented Nov. 14, 1950 FOOT CONTROL ARTIFICIAL LEGS John G. Catranisps yracuse, N.MY.'

Application January 28, 1948, Serial No. 4,856

6 Claims. (Cl. 3;;2)

-above the knee amputees embodying a knee lock which normally locks the knee joint from bending, and particularly to a control for the knee lock, which control is operated progressively by dorsiflexion of the foot, and also by the movement of the leg structure about a .forward and rearward horizontally extending axis between it and the foot structure, and by both of. these movements occurring during the walking cycle. The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to, the accompanying drawings in which like characters designate corresponding parts in all the views.

Figure 1 is a side elevation of an artificial leg embodying this foot control.

Figure 2 is an elevation looking to the left in Figure 1.

Figure 3 is a fragmentary elevation looking to r the left in Figure 1 showing the operation of the operating member for the knee look by the movement of the leg about a forwardly and rearwardly extending axis within the foot structure.

-Figure .& is a schematic view of the knee lock mechanism.

The numeral l designates the upper leg structure which is provided with a stump receiving socket 2, and a knee cap bracket or frame 3.

, 4=designates the lower leg structure, this being hinged at 5 to the knee cap frame 3 by a, knee joint shaft or pin. 6 designates the foot to which the lower leg structure is hinged at l by an ankle joint.

The lower leg structure includes a frame memher or tibia 8 which has a bifurcated head 9 at its upper end mounted on the knee joint pin 5, and

, the tibia at its lower end is' connected to the foot by the ankle joint I.

I designates the knee lock -mechanism as a whole. The mechanism here shown is vhydraulic and includes a cylinder ll mounted by a strap [2 on the tibia 8, and a piston I4 in the cylinder having its rod pivoted at I6 to a link I! which, in turn, is pivoted at its upper end at I8 to a bearing bracket l9 rigid with the frame 3. The radius of the pivot l8, relative to the knee joint pin 5, is such that during bending of the knee, the joint I8 moves in an upwardly curved arc and hence, tends to pull the piston l4 upward. The piston is also formed with a tail rod 20. The cross sectional areas of the two rods l5 and is such as to equalize the pressure areas on opposite sides ofthe piston.

I This invention relates to artificial legs for 7 The cylinder II is connected in a closed hydraulic system including a by-pass around the piston fromv the upper to the lower end of the :

cylinder including pipes

21, 22, 23 and 24, in 1 which islocated a control member, as a valve 25.

I The valve includes a normally closed, self-closing valve member 26 pressed against its seat by a .spring 21 and-operable off its seat different .dis- 1. .tancesby an operating member 28 which'ais actu- "ated byrthe flexions of the foot, as will hereinafter appear. 7

The hydraulic system further includes a second by-pass around the valve 25, this having a selfclosing check valve 30 therein arranged to check the flow of fluid from the upper end of the cylinder to the lower,but to permit comparatively free flow from the lower end of the cylinder to the upper. This second by-pass includes pipe 3| forming extension of the pipe 2|, and pipe 32 connected to the pipe 24 at the lower end of the cylinder.

When the knee flexes, as indicated by the broken line position of the socket and lower leg structure in Figure 1, the piston pulls upwardly in the cylinder l I, thus tending to move the fluid through the control valve to the lower end of the cylinder. The fluid can not flow unless the foot is flexing and hence, the control valve member 26 open. When the leg, straightens, the

piston [4 tends to move downward in the cylinder H and circulates the fluid through the -by-passaround the control valve controlled by the check valve which opens when the hydraulic E fluid is moved by the pressure of the piston M downward in the cylinder II.

The operating member 28 is actuated by the flexions of the foot, as will now be described. The foot includes an upper tarsus section 35, a'lower tarsus section 36, these sections being hinged together by aiorwardly and rearwardly extending horizontal hinge pin 31. The foot further includes a metatarsal section 38 hinged at 39 on a horizontal axis to the forward end of the lower tarsus section 36, the metatarsal section carrying a phalanges section 40 at its front end and hinged or pivoted at 40A thereto. The upper tarsus section is provided with a rigid forward extension 4| extending over the metatarsal section and spaced therefrom at its front end to permit pivotal movement of the metatarsal section 38 about its axis or hinge 39. There is a block 42 of yield ing material between the front end of the extension 4| and the metatarsal section, and also a spring 43 acts on the phalanges section to resist pivotal. movement thereof relative to the. meta- 3 tarsal section. The upper and lower tarsus sections constitute the rear portion of the foot structure to which the lower leg is connected by the ankle joint to the upper tarsus section.

The foot structure per se forms no part of this invention, and the invention relates primarily to the operation of the control for the knee lock. The foot control for the knee lock is operated by the dorsiflexion, or the movement of the metatarsal section about =its pivot 39, and by the movement of the upper tarsus 35 about the forward and rearward axis 3'! between it and the lower tarsus section 35.

The foot control includes a lever 451 extencling rearwardly from the metatarsal section along the lower tarsus section 36 and in a plane at one'si'de of the vertical plane of the rhinge axis iiLand a motion transmitting link 48 connecting the rear end of the lever 45 and the operating member 28, the link 48 having a clevis 39 at its upper end which is pivoted at 50'to the operatingmember 28.

The operating member 28 is connected Zto the stem of the valve 26 by a'lost motion, as .a pin and slot connection arranged topermit the valve 26 to open under sudden or excessive pressure relative to the operating member 28 and thus actas a relief valve.

The upper-leg structure also includes a fibula link 52 pivoted at its. upper .end at 53 to .the bracket Hlatv the lowerend of the stump socket :I,

eccentric to and below the knee joint pin 5, and

ing azstepandicreates a lost motion gap in the fibula. During ithe'taking of Ithe step and the knee action, the fibula, duetto its pivotal connection, moves downward, and then when.the legis ragain'straightened,:returnsthe foot .to its normal positionidueto the frictionofthe slip joint taking .up the :lost motion. The fibula forms no part of this inventionand, as its name implies, simulates the function of a natural fibula.

The valve member226 is .closed and hence, the

knee lock locked when theleg'is in straight or .extended position and the foot normal, or not flexed about the metatarsal joint '39 and the joint 40A.

In operation, during a walking cycle, assume :that the subject is insstanding position with the feet .offthei-natural and artificial legs together. and starts Walking by taking astepwithitheartificial leg. He shifshis weight to the 'natural leg, lifts the straight artificialleg and 'footoff the ground,

' swings it forward about the 'hip joint stiff legged fashion, and plants'the heel of the artificial'foot on the ground, the knee joint being locked. The body progresses forward "during this action so that the natural leg is inclining rearward from the hip. I-Ie then'shiftshis weightonto the'arti- ,ficial leg. The artificial foot then pivots as a unit about the-ankle joint so that the foot comes flat on the ground; this operation being permitted by the'fibula link. Be swings up on the toe of the artificial foot, the phalanges section pivoting at thejoint 45a against the action of the spring 43. The body in the meantime is progressing forward'and hence the artificial leg moves toward and into a rearward inclined position from the body, and the artificial foot pivots about the metatarsal joint 39, operating :theactuator 28 progressively to open the valve 26,- letting the leg begin to bend slightly at the knee joint at the time the foot of the natural leg, which has been swinging forward to take a new step, is about to be planted on the ground. The subject may hasten the knee unlocking operation by voluntarily swinging the artificial leg about the forward and rearward pivot 31, as shown in Figure 3, or unlock the knee look at any time by swinging the leg about the pivot 27 Whilethe artificial foot is on the ground. The opening of the valve :26, when the natural foot is about tobe planted on the ground, causes the step to be taken by the natural leg with a slight limp. When the natural foot is planted on the floor, and the weight transferred thereto,

the artificial leg, slightly bent at the knee, is lifted off the ground and it swings as a pendulum from rearward inclined position to forward inclined position to take another step. The artificial leg also straightens at the knee joint, the fluid passing freely past the check valve 3|! during the .downwardmovement of the piston '14.

The operating :member 28 is additionally actuated'bythe movement of the upper tarsus section about the pivot or hinge13'lby an inward swinging .of the artificial leg about :the pivot I relative to the foot when planted on the floor.

"Theleg and foot here illustrated is for the right leg in which the movement of the artificial leg is .to the left about the hinged axis 31 of the right artificial leg, as seen in Figure '3.

:The artificial :leg, when fitted to the amputee, i arranged so that the foot is straight, or toes outward in accordance withltherequirements of the amputee. :Hence, during the walking cycle the movements about both axes or hinges 39 and .31 .mayitake place during that .cycle and hence,

the valve 26 opens progressively and involuntarily. The-knee may be unlocked at anytime by the subject voluntarilyswinging-the leg laterally about the pivot .31 when the foot is on the floor or ground.

In descending inclines and steps, the amputee placesthefoot of the artificial leg, while theleg is extended, onto the next'lower step, and when he applies-his weight thereto and the body progressesxforward by the taking of a step with the natural;leg,='the flexing of the foot occurs partly opening the throttle valve 26 and releasing'the knee joint,'permitting theknee to bendunder the restrained flow of fluid past the partly open valve;26 whileithe footiof the natural leg isbeing placed .on .the stepbelow that on which the artificial-foot is located. With the foot of thenatural legon thestep, and the artificial legfiexed with .thefoot on the next upper step, the amputee lifts the artificial leg by lifting up on the hip joint, .or lifting-upon the stump, and-the artificial leg being unlocked at the knee joint, will swing'to- I ward straightened position into a position to be planted in its straight position on'the step next lowerto that on .which' the natural'footis planted.

"However, in-ascending inclines or steps, the amficial leg which'includes a-stump-receiving socket,

a lower leg structure hinged .by a knee joint to the lower end of the socket, a foot hinged to the lower leg structure by an ankle joint, and a knee lock mechanism carried by the lower leg structure and operable to lock the knee joint against hinging movement; the knee lock mechanism including a control member and an operating member therefor, the control member being in position to lock the knee joint when the leg is in straight or extended position, the foot including a rear portion and a metatarsal section hinged on a transverse axis to the rear portion of the foot, the ankle joint being between the lower leg structure and the rear portion of the foot, and motion transmitting means between the metatarsal section and the operating member to transmit the relative hinging movement of the metatarsal section and the rear portion of the foot to which it is hinged, to the operating member.

2. A foot control for the knee lock of an artificial leg which includes a stump receiving socket, a lower leg structure hinged by the knee joint to the lower end of the socket, a foot hinged to the lower leg structure by an ankle joint, and a knee lock mechanism carried by the lower leg structure and operable to lock the knee joint against hinging movement; the knee lock mechanismincluding a control member and an operating member therefor, the control member being in position to lock the knee joint when the leg is in straight or extended position, the foot including an upper tarsus section and a lower tarsus section hinged together on a forward and rearward horizontal hinged axis, the ankle joint being between the lower leg structure and the upper tarsus section, and motion transmitting connections between the foot and the operating member to transmit the relative hinging movement of the upper and lower tarsus sections to the operating member.

3. A foot control for the knee lock of an artificial leg which includes a stump receiving socket, a lower leg structure hinged by the knee joint to the lower end of the socket, a foot hinged to the lower leg structure by an ankle joint, and a knee lock mechanism carried by the lower leg structure and operable to lock the knee joint against hinging movement; the knee lock mechanism including a control member and an operating member therefor, the control member being in position to lock the knee joint when th leg is in straight or extended position, the foot including an upper tarsus section, a lower tarsus section hinged to the upper by a forwardly and rearwardly extending horizontal hinged joint, and a metatarsal section hinged to the front end of the lower tarsus section, and motion transmitting connections between the metatarsal section and the operating member to actuate it upon relative hinging movements of the metatarsal section and the lower tarsus section, and of the.

upper and lower tarsus sections.

4. A foot control for the knee lock of anartificial leg which includes a stump receiving socket, a lower leg structure hinged by a knee joint to the lower end of the socket, a foot hinged to the lower leg structure by an ankle joint, and a knee lock mechanism carried by the lower leg structure and operable to normally look the knee joint against hinging movement when the leg is in extended or straightened position; the knee lock mechanism including a control member self-returnable to normal position and an operating member therefor, the foot including an upper 6 tarsus section, a lower tarsus section hinged to the upper by a forwardly and rearwardly extending horizontal hinged joint, and a metatarsal section hinged to the front end of the lower tarsus section, a lever pivoted to the metatarsal section and extending lengthwise of the metatarsal section and the lower tarsus section at one sid of the vertical plane of the hinged joint between the tarsus sections, and a motion transmitting link connected at its opposite ends to said lever and to the operating member to operate the same on pivotal movement of the lever about its own axis upon relative pivotal movement of the metatarsal section and the lower tarsus section about the hinged connection between it and the lower tarsus section.

5. A foot control for the knee lock of an artificial leg which includes a stump receiving socket, a lower leg structure hinged by the knee joint to the lower end of the socket, a foot hinged to the lower leg structure by an ankle joint, and a knee lock mechanism carried by the lower leg structure and operable to lock the knee joint against hinging movement when the leg is in straight or extended position; the foot including upper and lower tarsus sections and a metatarsal section hinged to the front end of the lower tarsus section, the knee lock mechanism including a control member and an operating member therefor, the control member being normally in position to lock the knee joint when the leg is in straight or extended position, a lever pivotedto the metatarsal section and a motion transmitting link between it and the operating member to actuate the same upon relative movement of the metatarsal section and the tarsus sections about the hinged joint of the metatarsal section.

6. A foot control for the knee lock of an artificial leg which includes a stump receiving socket, a lower leg structure hinged by a knee joint to the lower end of the socket, a foot hinged to the lower leg structure by an ankle joint, and a knee lock mechanism carried by the lower leg structure and operable to lock the knee joint against hinging movement when the leg is in straight or extended position, the knee lock mechanism including a control member and an operating member therefor; the foot including an upper tarsus section, a lower tarsus section hinged tothe upper by a forwardly and rearwardly extending hinged joint, and a metatarsal section hinged to the front end of the lower tarsus section by a transverse hinged joint, a lever hinged to the metatarsal section and extending rearwardly along one side of the tarsus section at one side of the vertical axis of the joint between the tarsus sections,

and a motion transmitting link between said lever and the operating members.

JOHN G. C'ATRANIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 41,033 Vaughan Dec. 22, 1863 FOREIGN PATENTS Number Country Date 530,623 France Oct. 6, 1921 530,887 France Oct. 12, 1921