Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS2556525 A
Publication typeGrant
Publication date12 Jun 1951
Filing date8 Oct 1949
Priority date8 Oct 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
Next page
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 *8 Aug 1871 Improvement in universal joints for shaft-couplings
US288239 *10 Sep 188313 Nov 1883 George a
US2453969 *3 Apr 194716 Nov 1948Carter Edwin CArtificial limb
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3335428 *2 Nov 196415 Aug 1967Goodrich Co B FResilient prosthetic foot made from elastic polymers of different hardness
US3754286 *21 Jan 197228 Aug 1973Ryan MArtificial foot having ankle flexible mount
US3920610 *24 Apr 197418 Nov 1975Wagner EugeneMethod of making and tailoring prosthetic feet
US4177525 *9 Nov 197711 Dec 1979Ohio Willow Wood Co., Inc.Reinforced artificial foot and method of making
US4328594 *13 Feb 198011 May 1982Campbell John WProsthetic foot
US4395783 *16 Jul 19812 Aug 1983Vessa LimitedMethod of making an artificial leg
US4442554 *12 Feb 198217 Apr 1984Arthur CopesBiomechanical ankle device
US5004477 *20 Oct 19892 Apr 1991Establissements ProteorProsthesis for leg amputation and a process for its manufacture
US5062859 *11 Jun 19905 Nov 1991Otto Bock Orthopaedische Industrie Besitz- und Verwaltungs-Kommanditgesel lschaftProsthetic foot having z shaped insert
US5156632 *8 Nov 199120 Oct 1992Otto Bock Orthopaedische Industrie Besitz- und Verwaltungs-Kommanditgesel lschaftJointless prosthetic foot
US5258039 *15 Nov 19912 Nov 1993The National University Of SingaporeEnergy storing composite prosthetic foot
US5458656 *20 Dec 199317 Oct 1995Flex-FootEnergy-storing prosthesis leg pylon vertical shock leg
US5486209 *1 Jul 199423 Jan 1996Phillips; Van L.Foot prosthesis having auxiliary ankle construction
US5509938 *4 Jan 199423 Apr 1996Phillips; Van L.Prosthetic foot incorporating adjustable bladder
US5514185 *21 Jan 19947 May 1996Phillips; Van L.Split foot prosthesis
US5514186 *8 Mar 19947 May 1996Phillips; Van L.Attachment construction for prosthesis
US5549714 *12 Jan 199527 Aug 1996Phillips; Van L.Symes foot prosthesis
US5593457 *22 Sep 199514 Jan 1997Phillips; Van L.Foot prosthesis having auxiliary ankle construction
US5728176 *30 Oct 199517 Mar 1998Flex-Foot, Inc.Attachment construction for prosthesis
US5766265 *7 Jun 199516 Jun 1998Phillips; Van L.Prosthetic foot having curved integral support
US5899944 *23 Apr 19964 May 1999Phillips; Van L.Prosthetic foot incorporating compressible members
US5976191 *8 Oct 19962 Nov 1999Phillips; Van L.Foot prosthesis having curved forefoot
US5993488 *13 May 199830 Nov 1999Phillips; Van L.Prosthesis with resilient ankle block
US620693421 Aug 199827 Mar 2001Flex-Foot, Inc.Ankle block with spring inserts
US62804799 Apr 199928 Aug 2001Flex-Foot, Inc.Foot prosthesis having cushioned ankle
US64065002 Nov 199918 Jun 2002Van L. PhillipsFoot prosthesis having curved forefoot
US644399522 Dec 20003 Sep 2002Barry W. TownsendProsthetic foot
US652781116 Dec 19974 Mar 2003Van L. PhillipsFoot prosthesis with modular foot plate
US674326031 Jul 20011 Jun 2004Barry W. TownsendProsthetic foot
US689973726 Oct 200031 May 2005Van L. PhillipsFoot prosthesis having cushioned ankle
US69360742 Mar 200430 Aug 2005Barry W. TownsendProsthetic foot
US706372717 Dec 200220 Jun 2006Van L. PhillipsFoot prosthesis having cushioned ankle
US710872310 Jun 200419 Sep 2006Townsend Barry WProsthetic foot
US727901111 Feb 20049 Oct 2007Phillips Van LFoot prosthesis having cushioned ankle
US735445614 Sep 20048 Apr 2008Phillips Van LFoot prosthesis having cushioned ankle
US7503937 *29 Jun 200717 Mar 2009Ossur HfProsthetic foot
US77714881 Oct 200810 Aug 2010Ossur HfProsthetic foot
US78791101 Dec 20091 Feb 2011Ossur HfFoot prosthesis having cushioned ankle
US81778551 Oct 200815 May 2012Ossur HfProsthetic foot
US8685109 *24 Mar 20091 Apr 2014össur hfSmooth rollover insole for prosthetic foot
US91681587 Mar 201427 Oct 2015össur hfSmooth rollover insole for prosthetic foot
US93518531 Dec 201431 May 2016The Ohio Willow Wood CompanyProsthetic foot
US20030093158 *17 Dec 200215 May 2003Phillips Van L.Foot prosthesis having cushioned ankle
US20040162623 *11 Feb 200419 Aug 2004Phillips Van L.Foot prosthesis having cushioned ankle
US20040199265 *2 Mar 20047 Oct 2004Townsend Barry W.Prosthetic foot
US20040225376 *10 Jun 200411 Nov 2004Townsend Barry W.Prosthetic foot
US20050038525 *15 Jun 200417 Feb 2005The Ohio Willow Wood CompanyShock absorbing prosthetic foot for use with prosthetic ankle
US20050234563 *14 Sep 200420 Oct 2005Phillips Van LFoot prosthesis having cushioned ankle
US20050284160 *25 Jun 200429 Dec 2005Johnson Controls Technology CompanyMethod of and apparatus for evaluating the performance of a control system
US20080004719 *29 Jun 20073 Jan 2008Sigurdur AsgeirssonProsthetic foot
US20090030531 *1 Oct 200829 Jan 2009Sigurdur AsgeirssonProsthetic foot
US20090043403 *1 Oct 200812 Feb 2009Sigurdur AsgeirssonProsthetic foot
US20100004757 *24 Mar 20097 Jan 2010Ossur HfSmooth rollover insole for prosthetic foot
US20100106260 *1 Dec 200929 Apr 2010Phillips Van LFoot prosthesis having cushioned ankle
USD795433 *1 Jun 201622 Aug 2017Össur Iceland EhfProsthetic foot cover
DE2341887A1 *18 Aug 197327 Feb 1975Ipos Gmbh & Co KgKunstfuss fuer beinprothesen
DE3918810A1 *9 Jun 198913 Dec 1990Bock Orthopaed IndGelenkloser prothesenfuss
EP0277175A1 *23 Jul 198710 Aug 1988Ohio Willow Wood IncProsthetic foot.
EP0277175A4 *23 Jul 19875 Sep 1990The Ohio Willow Wood Company, Inc.Prosthetic foot
WO2008005424A22 Jul 200710 Jan 2008Ossur HfProsthetic foot
WO2008005424A3 *2 Jul 200712 Jun 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