AU730894B2 - Joint extension assist hinge mechanism - Google Patents

Description

Regulation 3.2 -1-

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT APPLICANT: ORTHOTIC CONSULTANTS ASIA PACIFIC PTY. LIMITED

NUMBER:

FILING DATE: Invention Title: JOINT EXTENSION ASSIST HINGE MECHANISM The following statement is a full description of this invention, including the best method of performing it known to me: 2 JOINT EXTENSION ASSIST HINGE MECHANISM This invention relates to a joint extension assist hinge mechanism which aids in the treatment associated with either the manipulation or reconstruction of bodily joints and the method employed in use of such apparatus Reconstruction surgery is quite often carried out on body joints, such as elbows and knees. If one considers a knee where ligaments have become detached from the bones, following surgery, :°oooe physiotherapy is usually necessary to restore joint function.

Physiotherapy includes stretching exercises to improve flexion (that is, movement of connected parts of the body towards each other) and extension (that is, movement which is opposite to that of flexion).

In some instances reconstructive surgery of body joints such as elbows and knees may not achieve the desired result in that the arm or leg is unable to attain either full extension or full flexion, or both. It would in such instances be desirable to have the use of D: \WP51\SPEC\ORTHOTIC.CAP\VM\12 August, 1997 an apparatus which would promote and assist joint extension or flexion, such apparatus being able to sustain a continuously applied, adjustable force.

Further to this, it has been found that, when a patient rests after a course of physiotherapy the gain in mobility of a joint is often lost.

It is an object of the invention to overcome this disadvantage as well as those associated with limits in the range of extension and flexion of a limb joint.

The invention in its broadest sense comprises a method of mobilising bodily joints comprising positioning a joint extension assistance hinge apparatus(1) on each side of an anatomical joint, such apparatus comprising an upper geared arm(2) which is adapted to be connected to the limb above the joint and a geared lever arm(3), the two arms being co-planar and pivotally connected at the joint end(4) to a lower arm(5) positioned underneath said upper geared arm(2) and geared lever arm(3), so that for every one degree of movement of the upper arm(2), the geared lever arm(3) moves D:\WP51\SPEC\ORTHOTIC.CAP\VM\12 August, 1997 4 twice the amount, and said lower arm(5) being adapted to be connected to a limb below the joint, and means whereby the lever arm(3) can be connected to the upper arm(2) in such a way as to apply tension thereto.

In order that the invention shall be more readily understood, we shall describe one particular form of a joint extension assist hinge mechanism with reference to the accompanying drawings, in which:

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Fig 1. shows a plan view of a joint extension assist hinge •mechanism.

Fig 2. shows a side elevation of a joint extension assist hinge mechanism.

Because of the gearing(6) between the upper arm(2) and the lever arm(3), any pressure applied to the lever arm(3) is multiplied when acting on the upper arm.

D:\WP51\SPEC\ORTHOTIC.CAP\VM\12 August, 1997 It may be preferred that the lower arm comprises a back plate(7) including a motion limiting mechanism(8), and said geared lever arm at its non-joint end has an aperture(9), whereby a tensor(10) can run from said aperture to a corresponding position on the upper arm.

In order that the invention may be more readily understood, we shall describe a preferred embodiment of the invention.

The invention essentially consists of a joint extension assist apparatus(l) which may be positioned on each side of an anatomical joint, such apparatus comprising a lower arm(5), which is adapted S. to be connected to a limb below the joint, and to which is pivotally fastened at the joint end(4), an upper geared arm(2) which is adapted to be connected to the limb above the joint. This arm has a gear(6) formed at its joint end(4). The joint end(4) of the geared lever arm(3) and joint end(4) of the upper geared arm(2) abut one another and each have geared teeth(ll) on their respective ends allowing a variety of angles to be attained when the two respective arms are moved by manual means.

D:\WP51\SPEC\ORTHOTIC.CAP\VM\12 August, 1997 The motion and thus the attainable positions of the geared upper arm(2) are limited by means of a motion limiting mechanism(8) comprising limiting screws(12) or other similar devices which may be positioned along a semi-circular narrow aperture(13) at the far end of the lower arm, the limiting screws(12) controlling the degree of motion of the upper arm(2) so that for every one degree of movement of the upper arm(2), the geared lever arm(3) moves twice the amount.

On attaining the required position by manual movement of the arms, a cover plate(14) made of either metal, plastic or other appropriate material is positioned over the two geared arms so as to enable the geared arms to remain in a desired position.

The geared lever arm(3) and the geared upper arm(2) are preferably made of a either a metal or metal alloy as is the lower though it may also be possible for the lower arm(5) to be made of a suitable plastic.

At the near end of the geared lever arm(3) is an aperture(9) of fixed diameter which enables a tensor(10) to run from the said D:\WP51\SPEC\ORTHOTIC.CAP\VM\12 August, 1997 7 aperture to a corresponding position on the upper arm(2), the tension of the strap or like on the geared lever arm(3) providing an extension or flexion movement about the axis of the anatomical joint.

The tension of the tensor(10) on the geared lever arm(3) provides an extension or flexion moment about the point corresponding to the anatomical axis so that for every one degree of movement of the geared upper arm(2), the geared lever arm(3) moves twice the amount.

It is envisaged that other embodiments of the invention will exhibit any number of and any combination of the features of the previously described two embodiments.

Whilst we have described herein one specific embodiment of the invention it is to be understood that variations and modifications in this can be made without departing from the spirit and scope thereof.

D:\WP51\SPEC\ORTHOTIC.CAP\VM\12 August, 1997

Claims (12)

1. A method of mobilising bodily joints comprising positioning a joint extension assistance hinge apparatus adjacent an anatomical joint, such apparatus comprising an upper geared arm which is adapted to be connected to the limb above the joint and a geared lever arm, the two arms being co-planar and pivotally connected at a joint end to a lower arm positioned underneath said upper geared arm and geared lever arm, so that for every one degree of movement of the upper arm, the geared lever arm moves twice the amount, and said lower arm being adapted to be connected to a limb below the joint, and means whereby the lever arm can be connected to the upper arm in such a way as to apply tension thereto.

2. A method as claimed in Claim 1 wherein the lower arm is adapted to be connected to the limb below the joint and to which is pivotally fastened at the joint end, a geared lever arm which is adapted to be connected to the limb above Sthe joint. o*

3. A method as claimed in Claims 1 or 2 wherein the joint end of the geared lever arm and the joint end of the upper geared arm abutt one another and each possessing geared teeth on their respective ends. ':\WP51\SPEC\ORTHOTIC.CAP\VM\11 January, 2001

4. A method as claimed in any preceding claim wherein the two upper arms are adjusted by manual means before attachment to an anatomical joint so that a required initial angle between the two arms can be selected.

A method as claimed in claim 5 wherein the motion and thus the attainable positions of the geared upper arm are limited by means of a motion limiting mechanism.

6. A method as claimed in claim 6 wherein the motion limiting mechanism comprises a limiting screw or other similar device which is positioned along a :semi-circular narrow aperture situated at the far end of the lower arm, the limiting @9 screw controlling the degree of motion of the upper arm. p

7. A method as claimed in any preceding claim wherein the geared lever arm, at its near end comprises an aperture of fixed diameter which enables a tensor to run from the said aperture to a corresponding position on the upper arm, the a tension of the tensor on the geared lever arm providing an extension or flexion movement about the axis of the anatomical joint.

8. A method as claimed in claim 8 wherein the tension of the tensor on the geared lever arm provides an extension or flexion moment about the point corresponding to the anatomical axis so that for every one degree of movement of the geared upper arm, the geared lever arm moves twice the amount. \WP51\SPEC\ORTHOTIC.CAP\VM\11 January, 2001

9. A joint extension assistance hinge apparatus as used with the method of any of the preceding claims such apparatus being positioned adjacent an anatomical joint, and comprising an upper geared arm which is adapted to be connected to the limb above the joint and a geared lever arm, the two arms being co-planar and pivotally connected at the joint end to a lower arm positioned underneath said upper geared arm and geared lever arm, so that for every one degree of movement of the upper arm, the geared lever arm moves twice the amount, and said lower arm being adapted to be connected to a limb below the joint, and means whereby the lever arm can be connected to the upper arm in such a way as to apply tension thereto. 0

10. An apparatus as claimed in claim 9 wherein the geared upper arm is made of either a metal or metal alloy as is the lower arm though it may also be possible for the lower arm to be made of a suitable plastic. t

11. A method as substantially herein before described with reference to the *0*g accompanying drawings. a a

12. An apparatus as herein before described with reference to the accompanying drawings. DATED THIS 12 DAY OF August 1997 ORTHOTIC CONSULTANTS PTY LIMITED By Their Patent Attorneys A TATLOCK ASSOCIATES \WP51\SPEC\ORTHOTIC.CAP\VM\11 January, 2001