US2490796A

US2490796A - Artificial body member

Info

Publication number: US2490796A
Application number: US782276A
Authority: US
Inventors: Paul M Gettman; William T Fulton
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-10-27
Filing date: 1947-10-27
Publication date: 1949-12-13
Anticipated expiration: 1966-12-13

Description

1949 P. M. GETTMAN ET AL 2,490,796

ARTIFICIAL BODY MEMBER Filed 001:. 27, 1947 s Sheets-Sheet 1 PAUL MQGETTMAN- a WILLIAM T. FU LTON ISnnentor:

(Ittorneg;

D 1949 P. M. GETTMAN ET AL 2,490,796

ARTIFI CIAL BODY MEMBER Filed Oct. 27, 1947 5 Shets-Sheet 2 l4 4o Fla-4 54 PAUL GETTMAN & WILLIAM T. f-ULTON 3nnentors &; 'flz (Ittomegs k I, 22 I 828 I I Dec. 13, 1949 GETTMAN. ET AL 2,490,796

ARTIFICIAL BODY MEMBER Filed Obt. 27, 1947 i 3 Sheets-Sheet 5 PAUL M. GETT'MAN a WILLIAM 1'. FULTON 3Iwentor5 Gttornegs Patented Dec. 13, 1949 7,

Paul M. Gettman and William '1.

' Wash.

ulton, Tacoma,

Applicationoctober 27, 1947, serial No. 782,276

This invention relates to improvements in an artificial body member and; more particularly, to an artificial leg for amputees.

It is a common complaint with persons using artificial legs that the legs are stifi and nonlifelike, both during walking and sitting; that they are difiicult to get accustomed to because of such conditions; that they will tend to throw the wearer down when the foot strikes upon an unusual hump or stone in the path; and that they do not properly receive the wearers weight when the foot touches the ground, leaving him with a great feeling of insecurity and a consequent high degree of nervous strain. Such complaints flow from the action of prior art legs during use, and seem to be due to unnatural action obtained artificially at the knee and ankle joints.

For example, some legs tend to bend in at the knee and so produce upon the wearer an impression that he is falling. Other leg and foot arrangements compel the foot to contact the ground with the heel disposed at an abrupt angle, and with the toe raised to a marked degree. As a result, the wearer, for the instant, has only a point-contact, and an extremely small one at that, with the ground, and then he must rock forward onto the foot and sole before his stability is restored. Artificial legs, in most cases, are most apparent to the casual observer, and are a constant source of concern to the wearer. Such is particularly true when the wearer is .seated and the artificial foot appears cocked in a very unnatural manner and tends to attract attention for that reason. A study of the natural human leg, during walking, reveals that during the stride the knee bends and the lower leg swings primarily about a horizontal pivot; the ankle, however, has two main degrees of movement: one about a horizontal lateral pivot and the other about a horizontal axial pivot; in addition, there is a certain torsional movement in the ankle. It is a result of failure to provide for all these movements, which have been described as a screwing action, that causes the user of an artificial leg great concern, with both physical and mental discomfort. It is therefore a prime object of this invention to overcome these conditions in the provision of this artificial leg.

In simulation of natural walking, it being noted that the foot normally approaches the ground flatly to receive and support the body weight, it

is another object of this invention to provide means in an artificial leg whereby there is a leveling-01f action of the artificial foot, as it is swung ahead of the knee to the forward portion 8 Claims.

' ofthe stride, andto do so in a natural, lifelike "the foregoing'objects, but which is simple to construct, durable for a long lifeof hard usage, and which will at all times afford to the wearer confidence and a feeling of safety.

The foregoing objects and others ancillary thereto we prefer toiaccomplish as follows:

' According to 'a preferred embodiment of our 'movement in a fore-and-aft swinging motion invention, we have deviseda foot portion that is pivotally associated with a lower leg portion for and a lateral pivotal motion and, in addition, may

be twisted or rotated'about the vertical axis of the lower leg. Resilient pivot means is employed to restrain lateral pivoting of the foot and to "insure its ordinary return to the neutral or normal position. Also, fore-and-aft swinging motion'of the foot relative to the lower leg is damp- *ened bythe use of a hydraulic or fluid-pressure double acting cylinder means, coupled by a link to the foot-portion in'rearward offset relation to the axis of pivotal motion. A releasable clutch associated with said link permits the retention of the foot in a desired fore-and-aft position during walking, and means for releasing the clutch is mounted between the lower leg and the usual upper leg socket portion, and is operable during-walking-when the leg portions are substantially aligned. In the hydraulic dampening means, there is a double acting piston which permits the passage of fluid under pressure from one chamber to another, on opposite sides of the piston, and which may be adjusted according to the requirements of the wearer to increase or decrease the dampening effect. Biasing means is included to tend to maintain the toe of the --foot cocked-down when it is unclutched and free to so move with respect to the fore-and-aft pivotal connection.

The 'novel features that we consider characteristic of our invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following 'description'of a specific embodiment when read in connection "with the accompanying drawings, in which:

Fig. 2 is an enlarged rear view in elevation of the lower leg portion of the assembly of Fig. 1;

Fig. 3 is a vertical, medial, sectional view of the leg of Fig. 1;

Fig. 4 is an enlarged, vertical, sectional view of the fluid pressure dampening means employed in the artificial leg;

Fig. 5 is a schematic view illustrating certain of the movements i obtained 'd'ur'ing i locomotion with the leg of this invention;

Figs. 6 and 7 are enlarged face views of the releasable clutch means employed in the leg and showing respectively the clutched arid released position of such means; and

Figs. 8 and 9 are cross sectional viewstaken'on:

lines 8-8 and 99, respectively, of Fig. 3.

The artificial leg of this invention comprises three main elements, namely the foot portion I0, the lower or intermediate leg element I2,'and the upper leg element I4. These elements are coupled together and arranged so that various degrees "of movement may be "had by the user in life like simulation of a natural "leg. 7

Referring to Figs. 1, '3,'8,"a11"d9. wherein"'is shown the details ofthe foot. i0, 'itwill be seen that within shoe I 6 is fitted a nieta'llicj or other "rigid, foot-formIB thatis'hollow"and"hasupstanding supporting "bosses20, '20, which "are spaced apart to cradle the square-ended pin '22.

Retainer caps 24, having-square"halfirecesses resilient, bushing 26 that isf'tlgh'tlyencircldby a fused-on bushing" 28 forming" an' integrahpart "of ankle block 30. By this 'structurethe, ankle block is resiliently coupled to"the"footformfor movement about theiaxis'of pin 22..in.a radial manner. Also the ankle block may be twisted about a Vertical axis l pas'sing perpendicularly through the axis of. pin-22l to affordanafi tdthe screwing motion lde'sir-able in simulation of normal walking motions. 'Suchtwis'ting is; possible through lateral. compressionaiid expansion of the resilient bushingZB.

- The lower leg portion 12 has a ptiinofidepend-ing cars 32, forming a fork that straddles-the=ankle block, and a pivot pin34passes throughthe-ankle block and the ears ofsaid-fork to-thereby-rcouple the lower leg and foot-togetheigvwhilepermitting a fore-and-aftswinging-motion of -the foot relative to the legabout the axis of pin-34. eAlshim '33, secured by screw 35, tothe ankle :block' under.

the forward edge ofthetube I3.of=;legportion- -I 2, determines the degree that the lower leg may -overturn the foot before-the two; elements 'must -move together. On-=theuppenend of tube l3 is e mounted the housing36,-which receives the socket 38 that is shaped to fit -the leg-stumpofltheamputee when the device is-in use. Socket 38- is'-held in place by screws 39-andis usually -formed-of a material that is readily molded :toethe shape' of the wearers stump toprovide ae comfortable fit.

Housing 36 may be variablypositioned on=tube I3 by compression clamp-3'lithat encircles-the lower end of the housing andcompressesittd tube I3.

The upper leg I portion I 4' includesthe :tapered s socket 40, which receives that portion of-the wear-- ers stump that is abovathaknee. Socket-w ts pivotably coupled to housing by

hinges

42 and 44, the arms of each of w-hichsarerigidly secured to the elements so ,joind by rivetsw.

' Within lower leg I2 is mounteda fluidepressure dampening means comprising the hollow cylinder 4 50, having access opening 52 on the upper end closed by screw plug 54, and the passage 56 in cluding the compression gland 58 that permits movement, under sealed conditions, of piston rod 5 60. A fixed piston 62 is secured between

collars

63 and 64 on rod 60, and has a rather sharp upper annular edge 66 of lesser diameter than the internal diameter of the cylinder 55. An inverted cup- =:"shape movable piston- 68 is superposed upon and *"surrounds'piston eIement' BZ, and is movable with I respect thereto, between the fixed collars 64 and "'65, so that the inner face of the cup wall 69 closes with or separates from the annular edge 66. Ports 10 in wall 69 are located within the diameter .15 of annular edge 66 and permit fluid, in this case oil, to flow to chamber I2 from the upper face of 'piston"62.' The outer periphery of the latter is of less diameter than the inner wall of cup 63 and is spaced therefrom, so that when piston 68 is moving downward oil will flow from lowercham- "ber '14 upward, around piston'62 withincup 68, over the edge 66, and out throughportslfl to chamber 12.

An axial passage 76, having lower outlet I7, and

" upper outlets "i8, is formed in rod 60 which extends above cup 68 and into chamber 12. A needle pointed screw 88, mounted in the upper. end of rod 68, permits the adjustment of the amount of .o'il that may move through ports'lfi. Access for such adjustment is had by removing plug 54.

On its lower extension, rodv iii) has spaced apart

collars

82, 84, between which is mountedthe slide bushing 86 that is ofless length thanthe space between the collars. Alateralarm 88, couple'd to bushing 86, extends rearward through opening ill from rod 60 and the slide bushing, and ispivotally coupled at 89 to link 90, which is also pivotally coupled by pin 92 to the ankle block:3ll at the rear of pin 34. A cross yoke 986s threadedly mounted on link 96 intermediate its ends. Between an upper position on tube I3 and the arms of yoke 96, are positioned tension springs 98, which-tend to ppull the heel of foot I0 upward, and consequently, to depress the toe. Such tilting action, however, 5 is restrained by unidirectional releasing clutch means. A blade lillldepends from arm 88 along- --side the fixed boss I02 and swinging-boss Hi4 on --one side, and the upwardly urged slidable boss: we :on the other side. Boss I82 is outstanding: from -base plate I 53 carried by tube I3. :Boss I041-is .-mounted on swinging plate I95 that pivots. on pin -Ill'l. A curved overhanging wall I08 on plate l'il5 receives boss I86, which is pressed therezagainst by -spring I09 and shoe IIU. When thebosses areas seen in Fig.'7, the clutch is released,; andnbla'de I0!) is free to move upwardunder the :influenceof springs 98. When the bosses are-.as-seenlin Figifi, -blade I00 is gripped by the'bossesand restrained .:from such movement.

'Plate I05 is normally'urged to theiiposition f Figs-6 by spring 5 l2 on pin Nix-and isrrmoved "against the spring by pressure appl-ied' tothetintegral cam H4 by roller lidon cran'k'armf I18 which action is had when downward-:pressureris delivered through bar I28, against spring I23.

In suitable guides I22, slide rod 12% is mounted on leg IE, between 'hingefliz and the upperrend -'=of bar I29, towhich the rodHiscoupled-satI126. "The upper end I2! of rod I26 zis loc'ate'd toube contacted"by abutment member 328 carried by the "upper arm of

hinge

42,50" that;.lwhen' thehupper and lower leg elements are brought into substan- 1 tial alignment; downward pressurexwill be :placed =upon rod 124,:bar I28 and'roller I=Ifi,-.=to cause the 76 latter to swing with pivoted crank arm H8 and exert pressure against cam H4 to move boss I04 away from contact with blade H30. Such action releases blade Hi0, and permits the springs 98 to exert a pull upward on the rear of foot l0, and to cause the toe to tilt down. Initial movement like this is possible without movement of the piston in chamber 59, because of the sliding of bushing 85 on rod 60 against the upper stop collar 82.

Referring to Fig. 5, wherein is shown schematically a series of positions assumed by a leg during walking, A designates the leg in weight-supporting relation to the foot, with the foot on the ground. As the weight moves forward in the beginning of a stride, it moves faster than the knee joint, and substantially faster than the ankle joint, which is cocked through the concentration of pressure on the toe. In this mechanism, this amounts to an application of pressure through link 90 to the piston rod Bil to draw the piston downward, such movement being dampened by the bleeding action of the oil through the passages 18 to chamber 12. At the same time, blade I is gripped in the clutch means between the various bosses, since with the knee bent, the cam presser roller i it is being pulled upward from the cam by the spring shown in Fig. 2.

Continued forward motion results in a further, but lifelike, lag in the ankle, accompanying a slight accelerated motion of the knee, as in position C of Fig. 5. The upper leg is swinging somewhat as a pendulum and this action results in motion of the lower leg from position B through stages C, D, and E, in the latter of which the lower leg is coming more into alignment with the upper leg. Such alignment as has been described results in a release of the clutch means acting on blade we, and under the action of springs 98, the toe drops and the heel raises in a leveling-off action of the sole of the foot, Ill.

Between stages E and F, the foot swings further forward, moving faster than the upper leg, as is indicated, and the amputee then shifts his weight to apply it to the artificial leg. The heel, still being slightly cocked because of the piston dampening means acting as a check on such movement, contacts the ground, whereupon further pressure is applied to link 9!), arm 88 and. piston rod 63, to cause an upward thrust on the piston and the oil in chamber 12. Through the bleeding of oil out of chamber 12, by way of passage ?8, a slow or restraining action is had. The amputee then again swings his weight over the ankle pivot, as in stages F, G, and H, and the cycle of the stride has been completed.

Should the foot on approaching the ground come upon a stick or stone, any twisting will be accommodated by the swinging of the ankle block about the axis of pin 22, or twisting with respect thereto.

By means of the mechanism that has been described, it is possible for an amputee to walk with a normal, screwing or twisting action in the ankle, and the normal hinging actions in both ankle and knee. The action is very lifelike to view and is most comfortable and normal to the wearer of such a leg and is fully satisfactory in use for long periods of time.

While we have shown and described particular embodiments of our invention, it will occur to those skilled in the art that various changes and modifications may be made without departing from the invention, and we therefore aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

Having thus described our invention, we claim:

1. An artificial leg, comprising: a lower leg element including a foot portion pivotally coupled, between its ends, thereto; an upper leg element freely hinged to the lower leg element and provided with means for securing said upper leg element in place on the stump of a wearer; a fluid pressure cylinder and double-acting dampening piston mounted in said lower leg element, said piston having a piston rod extending therefrom longitudinally of the lower leg element; a pair of spaced apart stops on said piston rod; an arm associated with said piston rod and slidable between said stops, said arm outstanding rearwardly fro-m said piston rod; a link between said arm and said foot portion to the rear of its pivotal connection with said lower leg element; spring means coupled to said link and lower leg element to impart an upward bias to the heel of said foot portion; a clutch blade carried by said arm; clutch means operable on said blade to retain the same against upward urgence of the biasing means; said clutch means including an opening cam, a presser member to act on said cam and having an extension to near said hinge joint, and an abutment carried by the upper leg element to press upon said p-resser member and operate thereon by approximate alignment of the upper leg with the lower leg element during walking.

2. An artificial leg, comprising: a lower leg element including a foot portion pivotally coupled, between its ends, thereto; an upper leg element freely hinged to the lower leg element and provided with means for securing said upper leg element in place on the stump of a wearer; a reciprocable member associated with the lower leg element for longitudinal movement thereof; a link coupled between said reciprocable member and a point on said foot-portion to the rear of its pivotal connection with the lower leg element; means for upwardly biasing said link; dampening means reciprocally operable longitudinally of the lower leg element and having a lost motion coupling with said reciprocable member; clutch means associated with said link and operable to retain the same against upward urgence of the biasing means, and clutch releasing means operable by approximate alignment of the upper leg with the lower leg element during walking.

3. An artificial leg, comprising: a lower leg element including a foot portion pivotally coupled, between its ends, thereto; an upper leg element freely hinged to the lower leg element and provided with means for securing said upper leg element in place on the stump of a wearer; a reciprocable arm rearwardly outstanding between the ends of said lower leg element and associated therewith for longitudinal movement; a link coupled between said arm and a point on said foot portion to the rear of its pivotal connection with the lower leg element; means for upwardly biasing said link; fluid pressure dampening means reciprocably operable longitudinally of the lower leg element and having a lost-motion coupling with said reciprocable arm; clutch means associated with said arm and operable to retain the same against upward urgence of the biasing means; and clutch releasing means operable by approximate alignment of the upper leg element with the lower leg element during walking.

4. An artificial leg, comprising: a lower leg elementga foot portion; on anlrle 'block pivoted to said lower leg portion to swingfore andaft thereof; said ankle block having an-elasti'c torsional coupling with said foot portion; an upper leg element- -freely hinged *to I the lower leg element and provided with means 'for securing the upper leg element in place on thestump-of a wearer; a reciprocablemember 'associatedwith the lower leg element for-longitudinal" movement'therecfla link'coup'led between saidreciprocable member and'a'point on 'said ankle block to the rearoi its pivotal connection with said lower leg element, means ioriupwardly biasing said' link, dampening means reciprocably operable longitudinally of the lower leg element and having a lost-motion connection with said reciprocable member, clutch means associated with saidlink and-operable to retain the same againstupward urgence of the biasing means,

and clutch releasing means operableby approximate alignment of the upper leg element with the lower leg element during walking.

5. An artificial leg, comprising: a lower leg element including a foot portion pivotally coupled, between its ends, thereto; an .upper leg element freely hinged to the lower leg. element and provided with means for securing said upper leg element in place on the stump of a wearer; a double-acting fluid pressure dampening, means attached at one operating. end to said lower leg element, a connector member: havingslost-motion connection with the other. operating. endvof said dampening means, a linkbetween said-connector member and the foot. portion: at a..point.to'=.the a rear of its pivotal connection; with the' lower-leg element, means. for upwardly .biasingthelink, clutch meansassociated withxsaidilinlc and; opera able to retain the same against the upward. ur-.

gence of the biasing ,means.. and clutch-release ing means operable by. approximatealignmentoi'. the upper leg element with the lower leg. element during walking.

6. An artificial leg comprisingzi a. lowenleg element including: a foot portion.:pi-votally..cou.-. pied, between its ends, thereto; an; upper; leg .'ele:-. ment freely hinged to thelower legelementiand provided with means for: securing. said .zuppen leg element in place on the stump of. a..wear.er;. a double-acting fluid pressure dampening.;means attached at one operating end. to saidlower leg. element, a connector member. having. lost-motion connection with the other operating end voisaid dampening, means, an arm rearwardlyoutstanding between the ends. ofthe lower. leg; element; and carried by said connector, a link between said arm and the. foot portion: atapointitmthe rear of its pivotal connection with.the lowerleg. element, means for upwardly. biasingathe link, clutch means associated with said link and operable to retain the. same against upward urgence of the biasing means, and clutch releasingmeansoperable by approximate alignment of; the upper.

leg element with the lower leg element during walking.

7."Anartificial leg; comprising: a--1ower1'eg element includinga foot portion pivotally'coupied; between its ends; thereto; an'upperleg elementfreelyhinged' to the lower leg element'and provided with meansfor securing said-upper leg element in place" onthe stump of a'wearer; a double-acting fluid pressure dampening "means attached" at one operating end to said"lower"leg element, a connectormember having lost-motion connection with the other operating end'of'said dampening means, an arm rearwardly outstanding between the. ends of the lower leg element and carried by said connector, a link'between said arm and the foot portion at a point to the rear of its pivotal connection with the lower. leg element, means for upwardly biasing said link, an element to be. clutched and carried by said arm, clutch means associated with said lower leg element and operable to grip said element. to be clutched to retain the same against the upward urgence of the biasing means, and clutch re"- leasing -means operable by approximate alignelement during walking.

8. An artificial leg, comprising: a lower leg element including a foot portion pivotally coupled, between its ends, thereto, and biased: =:to the uncooked position, an upper leg... element freely hinged to the lower leg element andfprovided with means for securing theuppenlegelement in place on the stump of a wearer, releasable means for retaining. cooked the joint 'between the foot portion and thelower leg. portion duringthe swing of the legfrom-the beginningof a stride, means for releasing said releasable means to permit lowering of the toe of the-foot portion before the end of the stride, and compressible means to retard cooking of the foot relative to the lower leg portion during the time the foot is bearing the wearers weight and resting on the ground as in walking.

PAUL M. GETTMAN. WILLIAM T. FULTON.

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

UNITED STATES PATENTS Number Name Date 2,020,423 Lofts NOV. 12, 1935 FOREIGN PATENTS Number Country Date 530,623 France Oct. 6, 1921 OTHER REFERENCES Research Reports on Artificial Limbs, Committee on Prosthetic Devices, National Research- Council, page 24.