Coil spring prosthetic foot

• US 5,443,528 A
• Filed: 11/17/1992
• Issued: 08/22/1995
• Est. Priority Date: 11/17/1992
• Status: Expired due to Fees

• Current Assignee: Medonics LLC
• Original Assignee: Scott Allen
• Inventors: Allen, Scott
• Primary Examiner(s): Willse, David H.
• Application Number:
  US07/977,806
• Time in Patent Office: 1,008 Days
• Field of Search: 623/55, 623/52, 623/24, 623/50, 623/53, 623/47
• US Class Current: 623/52
• CPC Class Codes: A61F 2/66 Feet; Ankle joints
• CPC Class Codes: A61F 2/70 electrical
• CPC Class Codes: A61F 2/76 Means for assembling, fitting or testing prostheses, e.g. for measuring or balancing, e.g. alignment means
• CPC Class Codes: A61F 2002/30276 frustopyramidal
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30469 using band clamps
• CPC Class Codes: A61F 2002/30494 Cooperating protrusions and recesses, e.g. radial serrations, located on abutting end surfaces of a longitudinal connection
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/5003 having damping means, e.g. shock absorbers for implantable joints A61F2002/30563
• CPC Class Codes: A61F 2002/5007 having elastic means different from springs, e.g. including an elastomeric insert elastic coating A61F2002/3007; springs A61F2002/5072; plate-like springs for feet A61F2002/6657
• CPC Class Codes: A61F 2002/502 for adjusting length for implantable joints A61F2002/3055
• CPC Class Codes: A61F 2002/5024 for adjusting thickness
• CPC Class Codes: A61F 2002/503 for adjusting elasticity, flexibility, spring rate or mechanical tension
• CPC Class Codes: A61F 2002/5055 Reinforcing prostheses by embedding particles or fibres during moulding or dipping, e.g. carbon fibre composites
• CPC Class Codes: A61F 2002/5059 the feeling of position
• CPC Class Codes: A61F 2002/5073 Helical springs, e.g. having at least one helical spring
• CPC Class Codes: A61F 2002/5079 Leaf springs A61F2002/6657 takes precedence
• CPC Class Codes: A61F 2002/6614 Feet
• CPC Class Codes: A61F 2002/6621 Toes
• CPC Class Codes: A61F 2002/6642 Heels
• CPC Class Codes: A61F 2002/6657 : having a plate-like or strip-like spring element, e.g. an energy-storing cantilever spring keel
• CPC Class Codes: A61F 2002/6664 : Dual structures made of two connected cantilevered leaf springs
• CPC Class Codes: A61F 2002/6671 : C-shaped
• CPC Class Codes: A61F 2002/704 : computer-controlled, e.g. robotic control
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2230/0086 : Pyramidal, tetrahedral, or wedge-shaped
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

A prosthetic foot formed by one continuous coil spring which has a foot center coil section, a heel extension section, and a forefoot extension section. Lateral and medial and torsional movement are accommodated. Energy is absorbed and stored by the prosthetic foot during heel strike in the gait cycle, energy is transferred to the forefoot extension section during foot roll-forward to toe-off in the gait cycle, and energy is released to provide a propelling force on the prosthetic foot at toe-off in the gait cycle. An apparatus allowing the wearer of the prosthetic foot to feel by physical sensation forces being applied to the prosthetic foot is included in one embodiment.

Claims

1. A foot comprising:

(a) a foot center coil section having a top and a bottom,

(b) a heel extension section extending in a first direction from the bottom of said foot center coil section,

(c) a forefoot extension section extending in a second direction from the bottom of said foot center coil section,

(d) means for absorbing and storing energy when vertical force is applied to the foot,

(f) means for adjusting spring stiffness and arch height; and

(e) a receptacle to accommodate said means for adjusting spring stiffness and arch height, wherein said receptacle is formed by the interior surface of said foot center coil section;

wherein said foot center coil section, said heel extension section, and said forefoot extension section constitute a coil spring to form the foot;

wherein said foot center coil section is adapted to serve as the unitary center of the coil spring in absorbing, storing and releasing energy;

wherein said energy absorbing and storing means comprises an arch; and

wherein said means for adjusting spring stiffness and arch height is installable in said receptacle.

2. A foot comprising:

(a) a foot center coil section having a top and a bottom,

(b) a heel extension section extending in a first direction from the bottom of said foot center coil section,

(c) a forefoot extension section extending in a second direction from the bottom of said foot center coil section,

(d) a shin section which extends from said foot center coil section;

(e) means for accommodating torsional movement about a longitudinal axis through said shin section;

wherein said foot center coil section comprises an anterior coil spring section and a posterior coil spring section and wherein said heel extension section extends from said anterior coil spring section and said forefoot extension section extends from said posterior coil section;

wherein said foot center coil section, heel extension section, and forefoot extension section constitute a coil spring to form the foot;

wherein said foot center coil section is adapted to serve as the unitary center of the coil spring in absorbing, storing and releasing energy;

wherein said torsional movement means comprises a plurality of torsional beams; and

wherein said torsional beams are generally configured as triangles in longitudinal cross section with two generally straight sides and one generally curved side.

3. A foot comprising:

(a) a foot center coil section having a top and a bottom,

(b) a heel extension section extending in a first direction from the bottom of said foot center coil section,

(c) a forefoot extension section extending in a second direction from the bottom of said foot center coil section,

(d) a shin section which extends from said foot center coil section;

(e) means for accommodating torsional movement about a longitudinal axis through said shin section;

wherein said foot center coil section comprises an anterior coil spring section and a posterior coil spring section and wherein said heel extension section extends from said anterior coil spring section and said forefoot extension section extends from said posterior coil section;

wherein said foot center coil section, heel extension section, and forefoot extension section constitute a coil spring to form the foot;

wherein said foot center coil section is adapted to serve as the unitary center of the coil spring in absorbing, storing and releasing energy;

wherein said torsional movement means comprises a plurality of torsional beams; and

wherein said torsional beams extend from said anterior coil spring section and from said posterior coil spring section;

4. A foot comprising:

(a) a foot center coil section having a top and a bottom,

(b) a heel extension section extending in a first direction from the bottom of said foot center coil section,

(c) a forefoot extension section extending in a second direction from the bottom of said foot center coil section; and

(d) means for absorbing and storing energy when vertical force is applied to the foot;

wherein said foot center coil section, heel extension section, and forefoot extension section constitute a coil spring to form the foot;

wherein said heel extension section is adapted to absorb and store energy at heel strike during the gait cycle;

wherein said foot center coil section is adapted to transfer energy stored during heel strike to another portion of the foot during foot roll-forward of the gait cycle;

wherein said forefoot extension section is adapted to release stored energy at toe-off during the gait cycle to provide a gait-enhancing propelling force on the foot;

wherein said energy absorbing means comprises;

(i) a shin section having a longitudinal axis, said shin section being connected to said foot center coil section, said shin section comprising a plurality of torsional beams;

wherein said torsional beams bow outward to absorb and store energy as vertical force is applied to the foot; and

wherein said shin section experiences a vertical displacement along its longitudinal axis as a result of bowing of said torsional beams.

5. A foot as recited in claim 4 wherein said energy absorbing means further comprises:

(ii) a center rod along the longitudinal axis of said shin section about which said torsional beams have the ability to bow.

6. A foot as recited in claim 5 wherein said energy absorbing means further comprises:

(iii) means for limiting vertical displacement of said shin section.

7. A foot as recited in claim 6 wherein said means for limiting vertical displacement comprises a clamp.