Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Leg – Foot
Patent
1997-08-26
1999-03-30
Prebilic, Paul B.
Prosthesis (i.e., artificial body members), parts thereof, or ai
Leg
Foot
623 47, A61F 266
Patent
active
058882391
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a jointless foot prosthesis with an internal foot spring extending from the heel to the forefoot, which is contained within a cosmetic covering and is connected by a bolt to an adapter which has a clamping means for releasable attachment to a prosthesis tube.
An embodiment of this kind can be found, for example, in U.S. Pat. No. 4,645,509. The adapter in this embodiment is drawn by the bolt tightly against an upper abutment surface of the internal foot spring and is disposed undisplaceably with respect to the latter. The adapter has a clamping sleeve into which the bottom end of the tube of the lower leg prosthesis can be inserted and can be clamped tightly by tightening a separate clamping screw.
U.S. Pat. No. 5,122,356 discloses a foot prosthesis equipped with a ball joint, having an internal foot spring which extends from the heel to the forefoot, is contained within a cosmetic covering, and is connected by a bolt to an adapter which forms the lower part of the ball joint whose upper member is integrated into the bottom end of a slotted clamping sleeve serving for releasable attachment to a prosthesis tube. The adapter rests with its bottom, configured as a cylinder segment and provided with serrations, upon a mating face of the internal foot spring whose serrations mesh with the serrations of the adapter. The bolt is passed through a slot in the internal foot spring which has a width corresponding to the diameter of the bolt and runs lengthwise of the foot, and at its bottom end the bolt thrusts against the bottom of an upper horizontal leg of the internal foot spring through a cylinder segment extending over the width of the slot. The ball joint can be removed from the adapter only by completely unscrewing the bolt.
FR 2.148.322 discloses a jointless foot prosthesis which has no internal foot spring but has a wooden core on which a cylinder segment is fastened by screws; the partially cylindrical wall of the cylinder segment is provided at its open top with serrations on which the bottom of an adapter is supported which is configured as a cylinder segment and provided with serrations, the two serrations being in mesh with one another. The upwardly projecting end of the adapter is provided with a recess into which the bottom end of a prosthesis tube is inserted. To serve as a clamping means, a slotted sleeve is inserted into the bottom end of the prosthesis tube and has an inner wall tapering from top to bottom, and in it there is guided a locking nut whose level is adjustable through a bolt passed from below through the wooden core and the two cylinder segments. When the bolt is tightened the locking nut is drawn downwardly, thereby spreading the split tube, thus forcing the prosthesis tube and the wall of its bottom end against the inner wall of the recess in the adapter.
This clamping attachment has the disadvantage that the clamping requires an expansion of the bottom end of the prosthesis tube, so that only appropriately thin-walled prosthesis tubes, or else only slotted prosthesis tubes, can be used. Mainly, however, the expansion of the tube in this area leads to fatigue fracture during the use of the foot prosthesis. Also, the expansion of the prosthesis tube does not take place uniformly over a sufficiently long section thereof. Since the actual clamping attachment has to take place between the outer wall of the tube and the inner wall of the adapter, although the adapter has to be made very rigid, a load-bearing damping surface can hardly be assured. High damping pressure can result in the cracking of the tube under flexural stress.
The invention is addressed to the problem of improving the function of the foot prosthesis described above.
This problem is solved according to the invention in conjunction with the features listed in the beginning, by the following additional features. provided with serrations, on a mating surface of the internal foot spring whose serrations are in mesh with the adapter. prosthesis tube is fitted. and having a width corresponding to the b
REFERENCES:
patent: 4463459 (1984-08-01), Shorter et al.
patent: 5112356 (1992-05-01), Harris et al.
Leppack Kai
Wellershaus Ulf
Otto Bock Orthopaedische Industrie Besitz-Und Verwaltungs-Komman
Prebilic Paul B.
Snow Bruce E.
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