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Publication numberUS2556525 A
Publication typeGrant
Publication dateJun 12, 1951
Filing dateOct 8, 1949
Priority dateOct 8, 1949
Publication numberUS 2556525 A, US 2556525A, US-A-2556525, US2556525 A, US2556525A
InventorsDrennon William M
Original AssigneeDrennon William M
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Artificial limb joint
US 2556525 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

June 12, 1951 w, DRENNQN 2,556,525

. ARTIFICIAL LIMB JOINT Filed 001;. 8, 1949 FIG.


BY I 74% 6 Patented June 12, 1951 UNHTED STATES PATENT Q'FFICE ARTIFICIAL LIMB JOINT William M. Drennon, South Gate, Calif.

Application October 8, 1949, Serial No. 120,336

1 Claim.

This invention has to do with artificial limbs and has as an object the provision of an improved joint therefor. While my improved joint is particularly well suited as an ankle joint, it should be understood, of course, that I do not intend to confine its use as an ankle joint, since it is capable of providing a joint between any two relatively movable parts of an artificial limb or the like.

It is a further object of the invention to provide a joint which has flexibility approaching that of a human joint such as an ankle joint.

Another object is the provision of a joint of this character which is capable of affording maximum comfort and which is extremely durable.

A further characteristic and advantage of my invention is its simplicity and economy of manufacture.

Other objects will appear hereinafter.

Without intending thereby to limit the broader scope of my invention as defined by the appended claim, I shall now describe an embodiment thereof which I, at present, prefer, for which purpose I shall refer to the accompanying drawings, wherein:'

Fig. 1 is a view partly in section and partly in side elevation of a foot and leg joined together by my improved ankle joint; I

Fig. 2 is a section taken on line 22 of Fig. 1;

Fig. 3 is a top plan view of the outer spring element; and

Fig. 4 is a top plan view of the inner spring element.

In the drawings, I show a foot portion F and a leg portion L.

The foot portion is composed of an outer layer 5 of soft material, such as sponge rubber, and a core 6 of a relatively stiif material, such as vulcanized rubber, although it is my preference that the core possess some degree of flexibility.

Within the core I embed a spring steel anchor plate In which serves as a lower anchor or foundation for the ankle joint now to be described. The foot portion is provided with an upwardly opening socket l5 within which I mount a pair of nested, concentric spiral springs l7, I8, and atop the spring elements I provide a cup-shaped metallic anchor plate or member 2!] which extends into and is secured to the leg L. As best seen in Figs. 2-4, the upper end of the outer spring I8 is provided with a loop 22 which is secured to anchor member 20 as by a bolt 23, while the lower end of the outer spring terminates in a loop 25 secured to the anchor plate In as by bolt 26.

The upper end of the inner spring I! terminates in a loop 30 secured to the anchor member 20 by bolt 21, while the lower end of the inner spring terminates in a hook 32 secured to the anchor plate by bolt 33.

It will be observed that the top and bottom loops of the outer spring are anchored at diametrically opposite points, while the top and bottom loops of the inner spring are also anchored at diametrically opposite points. That is, the respective ends of the outer spring are anchored at points spaced 180 from each other, while the respective ends of the inner spring are also anchored at points spaced 180 from each other, and spaced from the respective anchor points of the outer spring. Thus, no matter in which direction the foot is tilted relative to the leg, the stress is communicated directly to one of the anchor points, while vertical loads are taken by the springs in compression.

While, for illustrative purposes only, a portion of the rubber is shown in Fig. 1, I prefer to embed the springs l1, H3 in that portion of the rubber core 6 which fills socket I5. Thus, the rubber to some extent shares the vertical loads with the springs and it also protects the springs from exposure and corrosion.

The sole means of anchoring the foot to the leg is through the attachment of the springs to the anchor members, although in practice the leg and foot may be provided with some sort of flexible sheathing (not shown) which might afford some degree of attachment.

From the foregoing it will be apparent that my joint permits both twisting and tilting of the foot relative to the leg, the joint is fully cushioned and it affords suflicient resistance to too free tilting and twisting of the limb.

I claim:

In an artificial limb having a foot portion and a leg portion, a leaf spring embedded in the foot portion, a top anchor member secured to the leg portion, and a pair of nested spiral springs interposed between said leaf spring and said top anchor member, the upper end of the outer spring being anchored to said top anchor member and thelower end of said outer spring being anchored to the leaf spring at a point spaced from the point at which the top end thereof is anchored to the top anchor member; and the respective ends of the inner spring being anchored to said top anchor member and said leaf spring, respectively, at points spaced, respectively, 90 from the said anchor points of the outer spring.


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

UNITED STATES PATENTS Number Name Date 117,733 Black Aug. 8, 1871 288,239 Ingram Nov. 13, 1883 2,453,969 Carter Nov. 16, 1948

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US117733 *Aug 8, 1871 Improvement in universal joints for shaft-couplings
US288239 *Sep 10, 1883Nov 13, 1883 George a
US2453969 *Apr 3, 1947Nov 16, 1948Carter Edwin CArtificial limb
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3335428 *Nov 2, 1964Aug 15, 1967Goodrich Co B FResilient prosthetic foot made from elastic polymers of different hardness
US3754286 *Jan 21, 1972Aug 28, 1973Ryan MArtificial foot having ankle flexible mount
US3920610 *Apr 24, 1974Nov 18, 1975Wagner EugeneMethod of making and tailoring prosthetic feet
US4177525 *Nov 9, 1977Dec 11, 1979Ohio Willow Wood Co., Inc.Reinforced artificial foot and method of making
US4328594 *Feb 13, 1980May 11, 1982Campbell John WProsthetic foot
US4395783 *Jul 16, 1981Aug 2, 1983Vessa LimitedMethod of making an artificial leg
US4442554 *Feb 12, 1982Apr 17, 1984Arthur CopesBiomechanical ankle device
US5004477 *Oct 20, 1989Apr 2, 1991Establissements ProteorProsthesis for leg amputation and a process for its manufacture
US5062859 *Jun 11, 1990Nov 5, 1991Otto Bock Orthopaedische Industrie Besitz- und Verwaltungs-Kommanditgesel lschaftProsthetic foot having z shaped insert
US5156632 *Nov 8, 1991Oct 20, 1992Otto Bock Orthopaedische Industrie Besitz- und Verwaltungs-Kommanditgesel lschaftJointless prosthetic foot
US5258039 *Nov 15, 1991Nov 2, 1993The National University Of SingaporeEnergy storing composite prosthetic foot
US5458656 *Dec 20, 1993Oct 17, 1995Flex-FootEnergy-storing prosthesis leg pylon vertical shock leg
US5486209 *Jul 1, 1994Jan 23, 1996Phillips; Van L.Foot prosthesis having auxiliary ankle construction
US5509938 *Jan 4, 1994Apr 23, 1996Phillips; Van L.Prosthetic foot incorporating adjustable bladder
US5514185 *Jan 21, 1994May 7, 1996Phillips; Van L.Split foot prosthesis
US5514186 *Mar 8, 1994May 7, 1996Phillips; Van L.Attachment construction for prosthesis
US5549714 *Jan 12, 1995Aug 27, 1996Phillips; Van L.Symes foot prosthesis
US5593457 *Sep 22, 1995Jan 14, 1997Phillips; Van L.Foot prosthesis having auxiliary ankle construction
US5728176 *Oct 30, 1995Mar 17, 1998Flex-Foot, Inc.Attachment construction for prosthesis
US5766265 *Jun 7, 1995Jun 16, 1998Phillips; Van L.Prosthetic foot having curved integral support
US5899944 *Apr 23, 1996May 4, 1999Phillips; Van L.Prosthetic foot incorporating compressible members
US5976191 *Oct 8, 1996Nov 2, 1999Phillips; Van L.Foot prosthesis having curved forefoot
US5993488 *May 13, 1998Nov 30, 1999Phillips; Van L.Prosthesis with resilient ankle block
US6206934Aug 21, 1998Mar 27, 2001Flex-Foot, Inc.Ankle block with spring inserts
US6280479Apr 9, 1999Aug 28, 2001Flex-Foot, Inc.Foot prosthesis having cushioned ankle
US6406500Nov 2, 1999Jun 18, 2002Van L. PhillipsFoot prosthesis having curved forefoot
US6443995Dec 22, 2000Sep 3, 2002Barry W. TownsendProsthetic foot
US6527811Dec 16, 1997Mar 4, 2003Van L. PhillipsFoot prosthesis with modular foot plate
US6743260Jul 31, 2001Jun 1, 2004Barry W. TownsendProsthetic foot
US6899737Oct 26, 2000May 31, 2005Van L. PhillipsFoot prosthesis having cushioned ankle
US6936074Mar 2, 2004Aug 30, 2005Barry W. TownsendProsthetic foot
US7063727Dec 17, 2002Jun 20, 2006Van L. PhillipsFoot prosthesis having cushioned ankle
US7108723Jun 10, 2004Sep 19, 2006Townsend Barry WProsthetic foot
US7279011Feb 11, 2004Oct 9, 2007Phillips Van LFoot prosthesis having cushioned ankle
US7354456Sep 14, 2004Apr 8, 2008Phillips Van LFoot prosthesis having cushioned ankle
US7503937 *Jun 29, 2007Mar 17, 2009Ossur HfProsthetic foot
US7771488Oct 1, 2008Aug 10, 2010Ossur HfProsthetic foot
US7879110Dec 1, 2009Feb 1, 2011Ossur HfFoot prosthesis having cushioned ankle
US8177855Oct 1, 2008May 15, 2012Ossur HfProsthetic foot
US8685109 *Mar 24, 2009Apr 1, 2014össur hfSmooth rollover insole for prosthetic foot
US9168158Mar 7, 2014Oct 27, 2015össur hfSmooth rollover insole for prosthetic foot
US9351853Dec 1, 2014May 31, 2016The Ohio Willow Wood CompanyProsthetic foot
US20030093158 *Dec 17, 2002May 15, 2003Phillips Van L.Foot prosthesis having cushioned ankle
US20040162623 *Feb 11, 2004Aug 19, 2004Phillips Van L.Foot prosthesis having cushioned ankle
US20040199265 *Mar 2, 2004Oct 7, 2004Townsend Barry W.Prosthetic foot
US20040225376 *Jun 10, 2004Nov 11, 2004Townsend Barry W.Prosthetic foot
US20050038525 *Jun 15, 2004Feb 17, 2005The Ohio Willow Wood CompanyShock absorbing prosthetic foot for use with prosthetic ankle
US20050234563 *Sep 14, 2004Oct 20, 2005Phillips Van LFoot prosthesis having cushioned ankle
US20050284160 *Jun 25, 2004Dec 29, 2005Johnson Controls Technology CompanyMethod of and apparatus for evaluating the performance of a control system
US20080004719 *Jun 29, 2007Jan 3, 2008Sigurdur AsgeirssonProsthetic foot
US20090030531 *Oct 1, 2008Jan 29, 2009Sigurdur AsgeirssonProsthetic foot
US20090043403 *Oct 1, 2008Feb 12, 2009Sigurdur AsgeirssonProsthetic foot
US20100004757 *Mar 24, 2009Jan 7, 2010Ossur HfSmooth rollover insole for prosthetic foot
US20100106260 *Dec 1, 2009Apr 29, 2010Phillips Van LFoot prosthesis having cushioned ankle
DE2341887A1 *Aug 18, 1973Feb 27, 1975Ipos Gmbh & Co KgKunstfuss fuer beinprothesen
DE3918810A1 *Jun 9, 1989Dec 13, 1990Bock Orthopaed IndGelenkloser prothesenfuss
EP0277175A1 *Jul 23, 1987Aug 10, 1988Ohio Willow Wood IncProsthetic foot.
EP0277175A4 *Jul 23, 1987Sep 5, 1990The Ohio Willow Wood Company, Inc.Prosthetic foot
WO2008005424A2Jul 2, 2007Jan 10, 2008Ossur HfProsthetic foot
WO2008005424A3 *Jul 2, 2007Jun 12, 2008Ossur HfProsthetic foot
U.S. Classification623/49, D24/155, 403/229
International ClassificationA61F2/66, A61F2/60, A61F2/50
Cooperative ClassificationA61F2/66, A61F2002/5007, A61F2/6607, A61F2002/5076, A61F2002/6671
European ClassificationA61F2/66