US1834491A - Knee lock for artificial legs - Google Patents

Description

Dec. 1, 1931. J, JEP$QN 1,834,491

KNEE LOCK FOR ARTIFICIAL'LEGS Filed Aug. 22, 1929 tion.

Patented Dec. 1, 1931 NITED JOHN H. JEPsoN, or, MINNEAPOLIS, MINNESOTA I was oci: r Artrrrrcmn L tes Application filed August 22, 1929. 's riain 387,679;

My present invention has for its object the provision of a simple and highly eflicient manually controlled knee lock for an artificial leg, for a disartic'ulation at the hip, or foran amputation abovethe knee that leaves the stump so short that the patient'cannot control. the movement of-the artificial leg with which he is fitted and particularly when he is learning to walk or when going down stairs. By the use of this knee lock, the lower leg section maybe lockedatwill to the upper leg section'ofthe artificial-leg,

thus causing the'pati'ent to walk stiff legged,

but at the same time it gives himcontrol over the -moveme'nt of the artificial leg,

To the above end, the 'invention'consists of the novel devices and combination of devices hereinafter described and defined in the claims. 1

In the accompanying drawings, "which illustrate the invention," like characters indicate like parts throughout the several views.

Referringto the drawings Fig. 1 is a fragmentary view in front/elevation 'showing an artificial leg at the knee joint for an amputation above-the'knee and having the inventionembodied therein;

Fig. 2 is aview partly in side-elevation and partly in'section taken on the line 2-2 of Fig.1;

Fig. 3 is a fragmentarydetail view with some parts sectional on the irregular line 33 of Fig. 1 on an enlarged scale; I

Fig. 4 is' a perspective View ofthe anchor plate, on an enlarged s'cale, removed from the upper leg sectiomand with the knee lock removed therefrom; T V i S Fig. 5 is a fragmentary perspective view of the lock plate, onan enlarged scale, and

removed from the lower leg section; and

Fig. 6 is a fragmentary detail view-with some parts sectioned on the line 6-6 of Fig. 2, on an enlarged scale. i

The numerals 78 ndicate the upper and lower sections of an artificial leg, fo r an am- "p'utation above tlieknee, connected by a knee 'joint9 which sectionjand knee joint may be of j standard or any fwellg-kinown construcclearance for the detent l6.

.Al'simplecontrol is provided for the main thereof.

The knee lock includes avertically dis posed main-lever 10 intermediatelyfulcrumed at llto-a pair ofilaterally spaced rearwardly projecting bearing flanges on an anchor plate lb and between which flanges said lever extends and is held thereby against lateral shifting movement. This anchor plate 13 is fitted to the inner'sur face of the upper legsection 7 and rigidly'secured by nut equipped bolts 15 tosaid section.

:Theknee lock,as shown, is at the .front and transverse center of theartificial' leg and the V fulcrum 1 1 is substantially at the same elev'ation as the axiszof the knee oint 9. Formed on thelower end'of. the lever 10 is 'a wide forwardly projecting-hook or detent- 16-whichworks'through an aperture'17' in the upper legv section. 7 for cooperation with a lock plate 18. This lockplate 18 is fitted to the inner surface of the lower leg sections,- rigidly secured theretoYby rivets 19 .or other fastening devices, and is pro vided near. its top with an aperture 20 into which the detent l6 projects'when in operative position for engagement with the lock 5 plate above said aperture to connect the two 7 leg sections and 8, thereby holding the same istittwhen straight. The lower leg section 8 atitheaperture 20 is recessed at 21 to aflord 8'0 lever -10,. operable from the exterior of the legto movethedetent 16 into. orout. ofin- -terlocking engagement with the'lock plate 18. :This control is in the 'formzof a shortwide lever 22in bell-crank arrangement with main -lever10. and-its'inner arm isbifurcated. to .receive, between its prongs, the transversely reduced inner arm of the mainlever' 10, which works therebetween and is attached thereto 5 by. a cam connection. -Said cam connection,

' as shown, comprises a longitudinally extended slot 24 in the inner arm of the main lever 10, and acam pin 25, which extends through .saidslot and is anchored to the prongs of' 5 the? secondary lever 22. The outer arm of the secondary lever 22 works in an aperture 26, in the: upper leg section 7 atthe front A latch 27 and cooperating stop lug 28 nylon provided for holding the secondary lever 22 with a detent 16 in either an operative or an inoperative position. This latch 27 in is the form of a fiat member, which extends transvcrsely of the secondary lever 22, is mounted in a channel-like seat 29 formed therein and intermediately pivoted at 30 to said lever. A coiled spring 31 mounted in spring seats in the long arm of the secondary lever 22 and latch 27 yieldingly holds said latch in an operative position. The stop lug- 28 is formed with the anchor plate 14, extends in the path of movement of the'sh'ort end of the latch 27 and holds the secondarywlever=22 with the detent 16 in either an operative or an inoperative position.

a When the :latch27 isabovethezstop lug28, the detent 16 is in an operative position in :which it interlocks with the .lock .plate 1 8 ,and-holds :the :legsections 7 and 8 stiff and when said latch is below said lug, it holds the detent :16 in an inoperative position, as indicated by broken lines in Fig. :2. This ilatch'27 extends slightly outward of the outer .face of the upper leg sections 7 where the same may be easily manipulated by the .pa tient through his clothing to release said latchfrom'the stop lug28 by a lifting movement thereof, into a position,in"-wl1ich it will .pass over'ithe stop lug 28 during the move- -ment ofthe secondary lever 22. Said latch :27 also affords a convenient finger piece on dihevsecOlldaly lever :22 by which .it may be manipulated -:to operate the main lever 10, hence the detent 16.

For the purpose of this .case .itzis :not thought :necessaryi'to illustrate the kneelcon- :trol except the flexible connection 32 between theleg section 7-8 atthebackthereof which has a slight longitudinal stretch, limits the forward swinging movement of the lower leg=sectionr8 in respect .-to the upperleg sec tion 7 :and stops the same when properly aligned with said :upper leg section. This connection 32 may beof. any well-knownlcon- =struction. The relation between .the detent 16 and lock plate 18 is suehthat thenonnection '32 must be placed under slight tension by:a backward bending of thexleg atithekne'e -j oint ito cause the lock detent 16 :to enter the aperture 20 in the lock plate 18. iThisitenslon' under which themember 32zis placedrseicurely'holds thezdetent 16 interlocked with "the' latch late 18 so that thereiisno ilost moition' tliere etween.

From the above description, it visievident that :the above described knee lock maybe easilyoperated by the patient through his clothing .to :render said lock either -'operative or inoperative at will. rFurthermore,.theiknee lock is substantially entirely encased within the leg so that-it doesnot have any protruding parts that would holdthatpatientas clothing away from the leg and thus beaconspicuous.

l/Vhat I claim is:

1. The combination with the upper and lower sections of an artificial leg, and a knee joint connecting the same, of a lock for the knee joint within said leg for holding the sections thereof stifi when in a predetermined position, said lock comprising a main lever pivoted in'termediateof its ends to :the upper leg sect-ion and a secondary lever pivoted intermediate of its ends to the upper leg section,=said two leversfloei ng at an angle to each other, a positive cam connection between the inner-arms of-said two levers, said main lever having a detent on its outer arm, the outer armof the secondary lever being arranged where the same may be manually operated from theexterior of said'leg, alock ,plate on .the lower-leg sectionarranged to be engaged by the detent for holding the leg section stiff when in a predeterminedposition, a movable latch :memberron the outerarm of the secondary lever, and .a cooperating stop lug on the upper leg section for positively holding :the secondary lever with the main lever in a position inavhich its detent is interlocked with the lock plate. y

2. The combination with the upper and lower sectionsof an artificial leg, anda knee joint connecting the same, of a lock for -:the knee joint within said leg vfor holding the sections thereof stiff when-inapredetermined iposition, vsaidqloc'k comprising a main lever pivoted intermediate of its ends to the upper leg section and a secondary lever pivoted lin- =termedi-ate of .its ends to the upper-leg secition,:said,two levers bpeing=at anangletoeach other, a positive cam "connection between the inner arms of said two levers, said main lever having a detention its outer arm, the outer arm If the secondary {lever being arranged where the same ;may be manually operated af-rom-ltheexterior' oflsaid leg,a lock plate on the 'lower'leg section arranged to be engaged by the detent for holdinwthe leg, section stiff when :in a predetermined ;position, a movable latch member on the outer arm of the secondary lever, :and a cooperating stop lug on athe upper leg section for positively (holding the secondary lever'withthe main lever-in a :position in which its detent is either :interlocked withzthe ilock plate or Lreleased .there from. a

3. The combination with the upper and lower sections :of'anartificial leg, and a knee joint connecting the same, of a lock for the knee joint within the :leg: for 'holdingthe sections .thereof still when in a predetermined :position, said lock comprisinga main lever and a secondary lever, ieachaof .whichis :piV- .oted :intermetlia'te (if its: ends-to rthe upper leg section, and a lock shoulder on tthe :lower ileg; section,-said1 two leversibeing substantialzly perpendicular to each other and in the same .;.plane with their inner armsrldirectly connected for compound pivotal and sliding movements, the one upon the other, said main lever having a detent on its outer'end constructed and arranged to interlock with the lock shoulder, the outer arm of the secondary lever being arranged whereby the same may be manually operated from the exterior of the leg.

In testimony whereof I aflix my signature.

JOHN H. JEPSON.

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