Orthotic hinge system with spring-biased pawl control of ratchet member
View Patent ↗The invention relates to an orthopedic hinge system, including an outer and an inner lateral base, each substantially complemental in peripheral dimension to each other, the bases each having a major vertical axis, the inner base having a recess. Also included is an elongate distal member having a semi-circular pivot end including, upon a portion of the end, ratchet teeth pointing in a counter-clockwise direction, the pivot end rotationally secured to both of the bases. Further included is an elongate proximal member having a transverse end element proportioned for complemental securement within the recess of the inner base, transverse end element including an axis of rotation co-linear with an axis of rotation of the distal member and defining an axis of rotation of the pivot end of the distal member. The system also includes a cam lever including a pawl surface having teeth pointing in a clockwise direction and, upon contact with the ratchet teeth of the distal member, then complemental therewith, the lever having an axis of rotation co-linear with a second axis within a transverse end element of the proximal member, the lever also including a radial projection disposed radially oppositely from the pawl surface to which an end of a biasing spring is attached.
1. An orthopedic hinge system, comprising:
(a) an outer and an inner lateral base, each substantially complemental in peripheral dimension to each other, each of said bases having a major vertical axis, said inner lateral base having a recess therein;
(b) an elongate distal member having a pivot end including, upon a portion of said pivot end, ratchet teeth pointing in a counter-clockwise direction, said pivot end rotationally secured to both of said outer and inner lateral bases;
(c) an elongate proximal member having a transverse end element proportioned for complemental securement within said recess of said inner lateral base, said transverse end element including an axis of rotation of said pivot end of said distal member, said axis co-linear with an axis of rotation of said distal member;
(d) a cam lever including a pawl surface having pawl teeth pointing in a clockwise direction and, upon contact with said ratchet teeth of said distal member, said pawl teeth then complemental therewith, said cam lever having an axis of rotation co-linear with a second axis within said transverse end element of said proximal member, said cam lever also including a radial projection disposed radially oppositely from said pawl surface; and
(e) an extension spring having one end secured to said inner lateral base and an opposite end, secured to said radial projection of said cam lever, at a distance between ends of said spring causing extension of the spring and a normal bias of said pawl teeth into engagement with said ratchet teeth in which a counterclockwise motion of a handle of said cam lever stretches said spring, disengaging said pawl teeth from said ratchet teeth, and freeing said distal member to rotate relative to said proximal member.
2. The system as recited in claim 1 , in which said recess of said inner lateral base exhibits an axis substantially co-linear with a vertical axis of each of said lateral bases.
3. The system as recited in claim 1 , in which said pivot end of said distal member includes a non-ratchet surface proportioned for frictional contact with a pawl washer about said axis of rotation of said cam lever.
4. The system as recited in claim 3 comprising a stop pin in counter-clockwise position beyond said radial projection of said cam lever to thereby limit a range of motion of said cam lever and of said non-ratchet surface of said distal member.
5. The system as recited in claim 1 , in which said cam lever includes a cable screw opening to which a cable is secured.