US 2442151 A
Description (OCR text may contain errors)
May 25, 1948. E. L. STRICKLAND PNEUMATIC ARTIFICIAL FOOT Filed April 28, 1945 INVENTOR. fawnv LSTR/CKLAND ATTORNEY- Patented May 25, 1948 T UNITED STATES PATENT oFFicE PNEUMATIC ARTIFICIAL FOOT Edwin L. Strickland, Richmond, Calif.
Application April 28, 1945, Serial No. 590,775
1 *I'his invention relates to improvements in an artificial "member constructed to serve as a walking "medium and has particular reference to a pneumatic artificial foot wherein the ankle constru' ctioh is not only provided with full lateral movement, but can be absolutely and positively adjusted to fg-round level and will simulate in movement the action of the human ankle.
The principal object of the invention is the provision of a "foot of the character described that will relieve strain and fatigue in walking by utilizing an air cushion that eliminates jar to the body, and wherein by virtue of the construction employed will result in a perfect adjustment of the height to'the heel that relieves strain and effects a proper "balance.
A further object of the invention is the provision of a foot of the character described that is strong, durable, neat in appearance, affords positive protection to the working parts against the entrance of dirt and water in inclement weather, is readily "interchangeable, and yet is most economical to manufacture.
Other objects and advantages will be apparent dnr ing the course of the following description.
In the accompanying drawing wherein for the purpose of illustration is shown the preferred embodiment of the invention,
Fig. 1 is a view partly in section and partly in elevation illustrating the appliance as secured to a wooden shin portion, illustrating the inflatable bag in the foot portion and the mechanism permitting movement of the foot portion relative to the ankle portion, and
Fig. 2 is a bottom plan view of the foot section showing the zipper arrangement whereby the parts may be readily removed for replacement 01' adjustment.
Referring to the drawing, the numeral 4 indicates the wooden portion of an artificial leg member herein referred to as the shin portion provided with a reduced recessed extremity 5 receivable in a top casting 6 that is detachably secured by wood screws or other fastening elements 1 to said reduced extremity. It will be noted, as disclosed to advantage in Fig. 1, that said casting is equipped with an enlarged bore 9 and a central recess [0.
A cap casting or shell I l is fitted about the top casting 6, the side of the cap casting being spaced from the undercut top wall or upper end I2 of the top casting 6 to permit the positioning therein of an annular wedge-shaped bead l3 provided in the upper end of a foot covering M, the construction and purpose of which will be later described. It
willibe noted that said shell 'or oasting H is of a greater thickness at the front thereof as at 1-5 to thus provide :ameans or base for the reception of 'a machine screw 16 that serves to secure the shell H to the cap casting 6. The said shell is provided with an opening ll in communication and in alignment with the bore 9 to thus permit the passingtherethrough of a heel and toe adjus'ting cable I8. 7
The numeral l9 indicates as awhole, 'an'instep casting so termed because it conform rs; the shape "of the instep. "This main body portion of the casting is of substantial thickness and includes a tapered front portion 20, a'curvedbottom portion 2|, and a substantially flat top wall 22. The said casting has provided in its top "wall a mentral recess 23 and an 'angu'lar'slot 25 and carries on its top wall a rubber bumper 25 that is receivable in a slot 25 provided in the front thickened portion l5 of the shell 'rne "means for obtaining a lateral -ankle"rr'rovemen't between the upper. casting construction I and the instep casting, to thus eliminatean'd' obtain the ankle movement of the humanfoot, comprisesa ball and socket joint thatcomprises a top insert bearing '21 positioned in the recess It oi'the base 8 of the top casting and secured thereto by a machine screw 28; a lower insert bearing 29 that is positioned in the central recess 23 of the main body portion of an instep casting l9, and a bronze ball 30 free to rotate in the upper and lower bearings 21 and 29, and thus aiiording free lateral ankle movement and a positive adjustment of the ankle to ground levels.
To prevent the heel from flopping up and down I have provided the following construction: A cable or wire I8 has brazed to its upper end a threaded extension 32. The lower end of the cable is connected to an anchor screw 33 that extends transverse of the body of the instep casting. The said wire is encircled by a main spring that is positioned in the space 34 provided between the respective castings, the lower end of said spring being seated against a shoulder 35 provided by recessing the upper surface of the instep casting. Since the upper end of the spring contacts the base of the top casting the spring will readily contract and expand in the movement of the foot. To complete the assembly and to provide means for adjusting the heel portion a nut 36 is threaded on the threaded extension 32 while an auxiliary spring 31 encircles the upper end of the wire and is interposed between the base of the nut and a shoulder 38 formed by recessing the top surface of the base casting H adjacent th bore 9. V
a The foot portion l4, previously referred to, consists of a resilient member that conforms to the 1 shape of a foot, which covering is adhesively secured to the instep casting as at A and B, and has its upper wedge-shaped beaded extremity detachably secured between the upper casting and the shell J I I Y It will be noted that an inflatable inner tube 39 as illustrated to advantage inFig. 1 in a partly of said foot member relative to the shin portion to simulate the ankle movement of the human foot, a wedge shaped bead positioned on the 7 upper end of said foot member for detachably deflated condition, is positioned within said foot covering, and when inflated through the medium of a valve 39 will completely fill the space C of the foot covering, thus presenting a resilient pneumatic foot base on which readily be placed. 7 r
A zipper element is indicated 40 and is provided in the base of the foot covering. It serves as a medium for withdrawing therethr-ou'gh the mechanism above described when any of the parts of the construction requir repairing or necessitate adjustment.
If desired, ea liner maybe employed in the foot covering to prevent any undue pinchingof the inflatable member. It is obvious that the employment of the bumper; will absorb any undue shock in walking and that the present construction presents an artificial pneumatic foot that affords the maximum degree of ease and comfort and the absence of fatigue'in walking. I
It is to be understood that the form of my invention herewith shown and described is to be taken as a preferredvexample' of the same and that variouschanges relative to the shape size,
material and arrangement of parts may be readily resorted to without departing'from'the spirit of the invention or the scope of the subjoined claims.
' Havingthusdescribed my invention, I claim:
7 1. An artificial foot comprising a top casting secured to the shin portion of an artificial leg, anein'step casting; a pneumatic tube retaining 7 foot member secured to said instep casting,
means interposed between said casting and se-' cured'thereto and permitting lateral movement by the numeral a standard shoe can securing the latter to said top castingrand a closure means in the form of a zipper provided in the base of said foot member, whereby access is obtained to the interior of said foot member and said castings.
'2. An artificial.- foot comprising atop casting secured to the shin portionof an artificial leg,
the lower surface of said casting being recessed,
- an instep casting, a pneumatic tube retaining foot member secured to said instep casting; means interposed between said castings and secured thereto and permitting lateral movement of said foot member relative to the shin'p-o-rtion to simulate the ankle'movementof the human foot, said means comprising a ball and socket joint, a buffer mounted on the upper surface of the front portion of said instep casting andrreceivable in the recess on the lower surface ofjsaid top caste ing, and adjustin means positioned between said castings to adjust height to the heel, said adjusting means comprising a wire connecting said castings and being; interposed between the rear portions of said castings, and a main springIand an auxiliaryspring encirclin said Wire, the main; spring being .positionegi pbetween'rthe upper and lower castings, the auxiliary spring being housed Number" jNam e p v 708,685 White v Sept, 9, 1902 827,720 Erwin Aug; 7, 1.906 r 1,151,144 Wolfe et al. ,Aug. '24, 1915 1,804,915' co11ins; May 12,, 1931 a in the recess of the shin portion of the artificial leg. 7 7
The following references are of record in the