CA2519683C

CA2519683C - Mobility assistance apparatus and method

Info

Publication number: CA2519683C
Application number: CA002519683A
Authority: CA
Inventors: Barry W. Townsend; Byron K. Claudino
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-03-30
Filing date: 2005-09-15
Publication date: 2010-03-09
Anticipated expiration: 2025-09-15
Also published as: CA2519683A1

Abstract

A mobility assistance apparatus and a method for improving the mobility of a person using a walking aid, such as a cane, crutch, or walker, involve use of a device for ground engagement with ambulating using the walking aid. In a preferred example the device is a resilient lower extremity prosthesis that is capable of storing and releasing energy to generate propulsive force to aid mobility. The prosthesis has a foot, ankle and shank. The shank has a lower portion that is anterior facing convexly curved for generating forward propulsion with ambulating to aid mobility.

Description

MOBILITY ASSISTANCE APPARATUS AND METHOD
TECHNICAL FIELD

The present invention is directed to an improved mobility assistance apparatus and a method of improving the mobility of a person using a walking aid such as a cane, crutch or walker.

BACKGROUND
For over a century crutches and canes have remained virtually unchanged. Modifications to the crutch or cane itself have generally focused on ergonomic improvements in the physical structure versus functionai improvements to mobility. As such, modern ambulatory aids continue to suffer from many of the same functional limitations that plagued their predecessors.
An example of an early crutch, in U.S. Pat. No. 127,028 issued May 21, 1872, involves the use of a round rubber tip made of respective layers of rubber and canvas, each exposed at the tip, to prevent the crutch from slipping on a wet surface. The use of a passive curved rocker provided at the lower end of the crutch to increase the progression or ground covered with use of the crutch is taught by U.S. Pat. No. 267,680 issued Nov. 21, 1882. A
pneumatic cushion is used to form a curved rocker or bearer at the tip of the crutch in the patent to Mueller, U.S. Pat. No. 1,254,061 issued Jan. 22, 1918.
2o The U.S. Pat. No. 1,277,009 to Weldon, issued Aug. 27, 1918, teaches the use of curved segmental base pieces at the tip of the crutches for ground engagement.

More recently, examples of annular crutch tips with features to resist slipping when engaged with the ground are shown by U.S. Pat. Nos.:
3,040,757; 4,098,283; 4,411,284; 4,237,915 and 4,708,154. A radial crutch tip assembly with a base bottom surface and a resilient boot having a shape of a rocker is disclosed by Davis in each of U.S. Pat. Nos. 5,353,825; 5,409,029 and 5,465,745.

In other examples of walking aids, Wilkinson, U.S. Pat. No. 4,899,771, provides a foot member for the walking aid which is curved upwardly at its front and back ends to permit limited rolling of the foot member when used with a cane or crutch during a walking procedure. Similarly, Stephens discloses in U.S. Pat. No. 5,331,989 curving the front, rear and inner sides of the foot member of a walking aid to permit limited rolling of the crutch tip laterally as well as forward and backward.

Galan, in U.S. Pat. No. 5,829,463 provides the crutch tip with a heel portion or extension extending rearwardly from the tip at an upward angle.
The heel portion is used to prevent slipping when the user is rising from a seated position. Semanchik et al. disclose in U.S. Pat. No. 4,493,334 a walking aid having a foot pad shaped with a curved sole to simulate an 1o anatomical foot for achieving a rocking movement in use by imitating the phases of a normal gait, i.e. heel strike, foot flat and toe off. A published U.S.
patent application, U.S. Ser. No. 2001/0027802 Al to McGrath, is directed to a walking aid comprising a shaft and a foot assembly, in which the foot assembly includes in combination a sleeve member and a foot member adapted for relative axial sliding movement and including resilient movement-restraint means for alleviating problems from shock loading transferred up the walking aid to the user's hand, wrist, arm and shoulder.

One of the single largest deficiencies of conventional walking assistance devices is the excessive amount of energy needed to stabilize the walking system (the device and the user's body) with the ground, and to efficiently move the user's body through space. In fact, a crutch user expends as much as 2.5 times more energy to move his/her body mass, in space, as compared to an able bodied person. Furthermore, the lack of sufficient surface area at the ground engaging surface of a walking assistance device engenders other dangers such slippage on uneven or slick surfaces. While improvements have been made with respect to the surface area at the point of contact for walking assistance devices, these improvements have been one-dimensional due to the limitations of the designs. It has been found by Applicants that the principal limitation to even the most progressive crutch or cane tip, with respect to surface area and/or surface textures, is the inability of these devices to stabilize the walking system while simultaneously translating the vertical forces associated with crutch/cane ambulation into forward propulsion and mobility. There is a need for an improved mobility assistance apparatus capable of stabilizing the walking system while lessening the user's necessary energy expenditure and discomfort associated therewith.

SUMMARY OF THE INVENTION

An object of the present invention is to address the aforementioned need. To this end, the present invention is an improved mobility assistance apparatus and a method of improving the mobility of a person using a walking aid, which lessen the user's necessary energy expenditure and discomfort associated therewith by translating the vertical forces associated with ambulating using a walking aid into forward propulsion and mobility while at the same time stabilizing the walking system.

Accordingly, in one aspect of the present invention there is provided a method of improving the mobility of a person using a walking aid, comprising:
providing a resilient device substantially vertically oriented, the resilient device including a resilient foot, ankle and an upstanding, anteriorly facing, convexly curved shank, said resilient device being capable of storing and releasing energy in response to forces associated with ambulating using a walking aid which provides sagittal and transverse plane motion to generate forward propulsion to aid mobility; and connecting the upper end of the device to a lower portion of the walking aid with the device extending substantially below the walking aid for ground engagement and for generating forward propulsion to aid mobility with ambulating using the walking aid.
According to another aspect of the present invention there is provided a mobility assistance apparatus comprising, in combination: a walking aid; and a resilient substantially vertically oriented device connected to a lower portion of the walking aid for ground engagement and for generating forward propulsion to aid mobility, wherein the resilient device is a foot, ankle and an upstanding, anteriorly facing, convexly curved shank, the resilient device having an upper end connected to said lower portion and being capable of storing energy during force loading and releasing stored energy during force unloading, said device providing sagittal and transverse plane motion, wherein said device has a dynamic response characteristic to forces associated with ambulating using the walking aid which generates said forward propulsion to aid mobility.

The walking aid is preferably selected from the group consisting of a crutch, a cane, and a walker. The device connected to a lower port of the walking aid, the resilient prosthesis in the example embodiment, is capable of sagittal and transverse plane motion in response to forces associated with ambulating using the walking aid. This ensures that the bottom, ground engaging surface of the device/resilient prosthesis remains parallel to the ground, maintaining maximum contact and traction throughout the ambulatory cycle.

These and other objects, features and advantages of the present invention will be more apparent from a consideration of the following detailed description of disclosed example embodiments of the invention and the lo accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a left side view of a mobility assistance apparatus according to an embodiment of the invention.

FIG. 2 is an enlarged view from below and to one side of a coupling element of the apparatus of FIG. I by which a foot keel and a shank of the apparatus are connected.

FIG. 3 is an enlarged left side view of a portion of the apparatus of FIG.
I showing the connection between the lower end of a support member of the apparatus and the upper end of the shank.

FIG. 4 is a left side view of another form of a resilient lower extremity prosthesis for use in the apparatus of FIG. 1, the prosthesis having an outer protective covering, shown in outline, the covering having a slip resistant lower surface for ground engagement, a male pyramid connector of a male/female pyramid connection system being shown for connecting the prosthesis to a lower end of a supporting member of the apparatus.

FIG. 5 is a side view of another embodiment of a prosthetic foot for use in the mobility assistance apparatus, wherein the calf shank and foot keel and also a posterior calf device of the prosthesis are monolithically formed, the distal end of a spring of the posterior calf device being pivotably connected to the posterior of the foot keel.

FIG. 6 is a rear view of the prosthesis of FIG. 5.

FIG. 7 is a side view of another example of a prosthetic foot similar to that of FIGS. 5 and 6 for use in the mobility assistance apparatus, but where the foot keel, calf shank and posterior calf device are monolithically formed with three, side by side longitudinal sections freely movable with respect to 5 one another at their distal ends but connected at the proximal end of the calf shank, with the center section being wider, and at its distal surface higher, than the outer sections.

FIG. 8 is a top view of the prosthesis of FIG. 7.

FIG. 9 is a front view of the prosthesis of FIGS. 7 and 8.
FIG. 10 is a rear view of the prosthesis of FIGS. 7-9.

FIG. 11 is a side view of another form of the calf shank and foot keel of a prosthesis for the mobility assistance apparatus of the invention wherein the shank is monolithically formed with a posterior portion of the foot keel, which is connected by fasteners to a forefoot and midfoot forming member of the prosthesis.

FIG. 12 is a top view of the calf shank and foot keel of FIG. 11.

FIG. 13 is a rear view of the calf shank and foot keel of FIGS. 11 and 12.

DETAILED DESCRIPTION OF EMBODIMENTS

Referring now to FIGS. 1-3 of the drawings, a mobility assistance apparatus 1 according to a preferred embodiment is formed of a walking aid 2 in the form of a forearm crutch and a device 3 connected to a lower portion of the walking aid for ground engagement. The device 3 has a dynamic response characteristic to forces associated with ambulating using the walking aid which generates forward propulsion to aid mobility. The device 3 in the embodiment is a resilient lower extremity prosthesis, e.g. a prosthetic foot, which stores energy during force loading and releases stored energy during force unloading to generate propulsive force. In the example embodiment the device 3 is a prosthesis according to commonly owned U.S.
Pat. No. 6,562,075.

The prosthesis 3 includes a resilient foot 4, ankle 5 and calf shank 6.
The foot 4 includes a foot keel 7 and optionally a protective covering not shown in FIG. 1 but like covering 8 shown in outline in FIG. 4, for example.
The covering 8, which may be formed of rubber, has ridges 9 on the bottom, ground engaging surface thereof to resist slipping during use. If a separate protective covering is not employed on the device 3, ridges or other surface irregularities can be provided directly on the under surface of the foot keel to resist slippage as discussed below.

The shank 6 is connected to the foot keel by way of a coupling element lo 10 and fasteners 11 and 12 to form the ankle 5 of the prosthesis. At least a lower portion of the shank is anterior facing convexly curved. The foot keel is upwardly arched in its midportion. The adjacent radii of curvatures of the resilient foot keel and calf shank of the prosthesis create a dynamic response capability and motion outcome of the prosthesis in a direction having horizontal and vertical components as explained with reference to FIGS. 1 and 2 of U.S. Pat. No. 6,562,075, to generate a propulsive force during ambulating.

The walking aid 2 of the apparatus 1 is formed with a hollow staff 13 that serves as a support member capable of bearing vertical forces from the weight of the user on the crutch during use as a walking aid. A hand grip 25 and forearm support 26 are mounted on the staff. The length of the staff could be adjustable as by the use of adjustably telescoped staff portions, not shown.
While the walking aid 2 in the mobility assistance apparatus 1 is a forearm crutch, other types of walking aids could be used as the walking aid in the apparatus, including another type of crutch, a cane, or a walker, for maximizing functionality and mobility, while lessening the user's necessary energy expenditure and discomfort associated therewith.

The device 3 is preferably capable of sagittal and transverse plane motion in response to forces associated with ambulating using the walking 3o aid. Transverse plane motion, provided for example by the provision of longitudinally extending expansion joints 23 in the foot keel as disclosed in related U.S. Pat. No. 6,562,075 and/or by the use of a coupling element permitting motion of the foot about a joint axis which is at least primarily in the frontal and transverse planes as shown in FIGS. 28-35 of commonly owned related U.S. Patent Application Publication No. 2005/0177250, ensures, together with sagittal plane motion capability, that the bottom surface of the foot keel will remain parallel to the ground, maintaining maximum contact and traction throughout the ambulatory cycle. The energy storing prosthetic foot 3 is capable of enhancing and/or replicating the propulsion that an individual would experience at the foot, ankle, and calf during the gait cycle, if uninjured or able bodied.
In the absence of a protective covering on the prosthesis 3 as shown in FIG. 4, a rubber surface or a compressible foam surface is preferably bonded to the underside of the foot keel 7 using an epoxy glue, for example. The rubber or foam surface is preferably provided with a slip resistant/traction characteristic. For example, corrugated vanes could be formed on the ground engaging rubber or foam surface for increased traction over wet surfaces. In addition, or alternatively, a boot which fits over the entire body of the prosthetic foot keel, excluding the shank, can be used to achieve variable traction needs, the bottom surface of the boot being provided with a slip resistant surface, e.g. cleats, ridges, etc.
The releasable connection between the lower end of staff 13 and the upper end of shank 6 in the apparatus 1 is shown in the enlarged view of FIG.
3. The upper end of the shank is formed with an elongated opening 14 for receiving the lower end of staff 13. Once received in the opening, the staff is securely clamped to the shank by tightening bolts 15 and 16 to draw the free side edges 17 and 18 of the shank along the opening together. This connection can be readily adjusted by loosening the bolts, telescoping the staff relative to the shank to the desired position and reclamping the staff in the adjusted position by tightening the bolts.
The connection between the prosthesis and the walking aid/support member is not limited to that shown in the example embodiment of FIGS. 1-3.
Other types of connections including a conventional male/female pyramid system, for example, could be employed. The prosthetic foot 19 in FIG. 4, for use in a mobility assistance apparatus of the invention, has an adapter 20 bolted to the upper end of the shank 21. The adapter 20 has a male pyramid 22 thereon for reception in a complementarily shaped socket of an adapter provided on the lower end of staff 13.
The device 3 according to the invention may be formed from acetal homopolymer or copolymer (Delrin/Celcon), for example, or other materials including aluminum, carbon or graphite composites, glass, and/or Kevlar. In the preferred embodiment the device 3 is formed of acetal plastic, by either machining or injection molding.
The prosthetic foot 19 in FIG. 4 is similar to that in FIG. 1 although the shank 21 thereof is reversely curved on itself above an anterior convexly curved lower portion. Fins 24 are formed on the posterior side of the reversely curved portion of the shank to alter the flexing characteristic of the shank as discussed with respect to FIGS. 28-32 of commonly owned related U.S.
Patent Application Publication No. 2004/0122529.
The device 3 of the invention is not limited to the two examples of FIGS. 1 and 4. Other devices, particularly lower extremity prostheses/prosthetic feet capable of storing and releasing energy during use to generate propulsion could be used in the mobility assistance apparatus and method of the invention for stabilizing the walking system and lessening the user's necessary expenditure of energy and discomfort associated therein.
Examples of additional prosthesis for use in the mobility assistance apparatus of the invention are shown in FIGS. 5-13. These prostheses are relatively inexpensive in that they can be monolithically formed as by injection molding acetal plastic. The resulting mobility assistance apparatus employing the prosthesis is able to create power for enhancing mobility yet is low cost.
The prosthetic foot 147 of FIGS. 5 and 6 is characterized by a calf shank 148, foot keel 149 and posterior calf device 150 which are monolithically formed. The calf shank 148 has an anterior facing convexly curved lower portion extending upwardly from the foot keel as in previously described prostheses. The posterior calf device 150 is in the form of an elongated, resilient, curved spring connected at its proximal end to an upper portion of the calf shank and at its distal end the spring is pivotably connected to a posterior portion of the foot keel by a bracket with pivot pin 151 mounted on the distal end of the spring with the pin extending through an aperture 152 in the posterior end of the foot keel. The ends of pins 151 are anchored in the openings 152 in the foot keel as shown in the drawings. With anterior or posterior motion of the upper end of the calf shank in gait with the mobility assistance apparatus of the invention, the concavity of the curved spring will be expanded or compressed to store energy within the motion limits of the spring. The stored energy will then be returned upon force unloading in gait to add to the kinetic power available for propulsive force of the user's body.

The prosthesis in FIGS. 7-10 is a prosthetic foot 152 having three 1o longitudinal sections 153-155. Each longitudinal section is monolithically formed with a foot keel 156, calf shank 157 and posterior calf device 158. The sections 153-155 are movable independent of one another at their distal ends, where they are separated by gaps 159, but the sections are integral at their proximal ends, e.g. at the upper end of the calf shank. This integral construction can be provided by use of fasteners for connecting the proximal ends of the respective, separately formed longitudinal sections to one another. Alternatively, the resilient longitudinal sections can be monolithically formed with one another such that they are connected at their upper ends while freely movable relative to each other at their distal ends where gaps separate the sections.

The center longitudinal section 154 in the prosthesis 152 is wider than the medial and lateral sections 153 and 155 and also, at its distal end, it is higher than the sections 153 and 155. This construction provides advantages in support on uneven or inclined surfaces as discussed previously in connection with the use of a plurality of longitudinal anterior and posterior foot keel struts separated by expansion joints. The number of the plurality of longitudinal sections employed in the prosthesis can be other than three and the relative widths of the sections can be varied from that shown in FIGS. 7-10. The distal ends of the curved spring of posterior calf device 158 of each longitudinal section is formed integrally with the hindfoot of its foot keel rather than being pivotably connected thereto as in the embodiment of FIGS.
5 and 6. A suitable adapter, not shown, is connected to the upper end of the calf shank of the prosthesis 152 for connection with the support member, hollow shaft 13, of the walking aid 2 to form a mobility assistance apparatus of the invention as described in previous embodiments.

Another form of construction for the prosthetic foot for use with the invention is illustrated in FIGS. 11-13 wherein the prosthetic foot 160 5 comprises a calf shank 161 monolithically formed with a posterior portion and foot keel 163. The resilient member of the shank and hindfoot is connected to a resilient member 164 forming forefoot and midfoot portions of the foot keel by fasteners 165 and 166 as shown in the drawings. A posterior calf device, not shown in FIGS. 11-13, can be formed as part of the prosthesis 1 o as disclosed above. Likewise, an adapter for connection to a support member of a walking aid is to be attached to the upper end of the calf shank 161.

This concludes the description of the example embodiments. Although the present invention has been described with reference to a number of illustrative embodiments, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention.
More particularly, reasonable variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the foregoing disclosure, the drawings, and the appended claims without departing from the spirit of the invention. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims

1. A mobility assistance apparatus comprising, in combination: a walking aid; and a resilient substantially vertically oriented device connected to a lower portion of the walking aid for ground engagement and for generating forward propulsion to aid mobility, wherein the resilient device is a foot, ankle and an upstanding, anteriorly facing, convexly curved shank, the resilient device having an upper end connected to said lower portion and being capable of storing energy during force loading and releasing stored energy during force unloading, said device providing sagittal and transverse plane motion, wherein said device has a dynamic response characteristic to forces associated with ambulating using the walking aid which generates said forward propulsion to aid mobility.

2. The mobility assistance apparatus according to claim 1, wherein a lower power of the shank is anterior facing convexly curved.

3. The mobility assistance apparatus according to claim 1, wherein the foot includes a resilient foot keel, the shank being connected to the foot keel to form the ankle.

4. The mobility assistance apparatus according to claim 1, wherein the walking aid is selected from the group consisting of a crutch, a cane, and a walker.

5. The mobility assistance apparatus according to claim 1, wherein the device is monolithically formed.

6. The mobility assistance apparatus according to claim 1, wherein the device has a slip resistant lower surface for ground engagement.

7. The mobility assistance apparatus according to claim 1, wherein the walking aid is a crutch, and the upper end of the device is connected to a lower end of the crutch.

8. The mobility assistance apparatus according to claim 1, further comprising a releasable connection connecting the upper end of the device to the lower portion of the walking aid.

9. The mobility assistance apparatus according to claim 8, wherein the releasable connection is selected from the group consisting of a male/female pyramid system and an elongated opening at the upper end of the device which telescopingly receives the lower portion of the walking aid.

10. The mobility assistance apparatus according to claim 1, wherein the resilient device includes a resilient posterior calf device connected to an upper portion of the shank and a lower portion of the device, the posterior calf device flexing to store energy during force loading of the apparatus and return the stored energy during force unloading.

11. The mobility assistance apparatus according to claim 10, wherein the shank and the posterior calf device are monolithically formed.

12. The mobility assistance apparatus according to claim 11, wherein the foot and ankle are also monolithically formed with the shank and posterior calf device.

13. The mobility assistance apparatus according to claim 10, wherein the device includes a plurality of longitudinal sections each including respective foot, ankle, shank and posterior calf device sections, the longitudinal sections at their distal ends being movable independently of one another and at their proximal ends being integral with one another.

14. The mobility assistance apparatus according to claim 13, wherein the longitudinal sections are each monolithically formed.

15. A method of improving the mobility of a person using a walking aid, comprising: providing a resilient device substantially vertically oriented, the resilient device including a resilient foot, ankle and an upstanding anteriorly facing convexly curved shank, said resilient device being capable of storing and releasing energy in response to forces associated with ambulating using a walking aid which provides sagittal and transverse plane motion to generate forward propulsion to aid mobility; and connecting the upper end of the device to a lower portion of the walking aid with the device extending substantially below the walking aid for ground engagement and for generating said forward propulsion to aid mobility with ambulating using the walking aid.

16. The method of claim 15, wherein the connecting includes connecting an upper portion of the shank to a lower end of the walking aid.