WO2007009240A1 - Swing-phase controller with an artificial joint - Google Patents
Swing-phase controller with an artificial joint Download PDFInfo
- Publication number
- WO2007009240A1 WO2007009240A1 PCT/CA2006/001181 CA2006001181W WO2007009240A1 WO 2007009240 A1 WO2007009240 A1 WO 2007009240A1 CA 2006001181 W CA2006001181 W CA 2006001181W WO 2007009240 A1 WO2007009240 A1 WO 2007009240A1
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- WIPO (PCT)
- Prior art keywords
- piston
- artificial joint
- swing
- assembly
- engage
- Prior art date
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Classifications
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/50—Prostheses not implantable in the body
- A61F2/60—Artificial legs or feet or parts thereof
- A61F2/64—Knee joints
- A61F2/642—Polycentric joints, without longitudinal rotation
- A61F2/644—Polycentric joints, without longitudinal rotation of the single-bar or multi-bar linkage type
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/50—Prostheses not implantable in the body
- A61F2/68—Operating or control means
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/50—Prostheses not implantable in the body
- A61F2/68—Operating or control means
- A61F2/74—Operating or control means fluid, i.e. hydraulic or pneumatic
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/50—Prostheses not implantable in the body
- A61F2/68—Operating or control means
- A61F2/74—Operating or control means fluid, i.e. hydraulic or pneumatic
- A61F2/748—Valve systems
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
- A61F2/50—Prostheses not implantable in the body
- A61F2002/5016—Prostheses not implantable in the body adjustable
- A61F2002/502—Prostheses not implantable in the body adjustable for adjusting length
Definitions
- This invention relates in general to a mechanism for controlling a joint's movement and more particularly to an artificial joint with a swing-phase controller.
- Prior art artificial joints have addressed some of the noted issues for both stance and swing-phase control.
- many knees utilize hydraulic mechanisms to provide stance/swing-phase control including those described in US patents 5,376,137, 6,658,540 Bl and 6,652,585 B2. These devices address how the hydraulic mechanism is controlled to provide very high resistance to flexion during stance, and lower resistances to flexion and extension during swing.
- the prior art does not address a swing-phase controller that efficiently functions within an artificial joint having a dual axis (knee flexion axis and control axis) stance-phase controller.
- Figure 8 in an exploded view, illustrates the artificial joint of Figure 6.
- the swing-phase control means 18 further includes a piston and cylinder assembly 20 that is adapted to engage the stance-phase control means 12.
- the piston and cylinder assembly 20 has a first end 22 that is adapted to engage an upper coupling element 24 of the stance-phase control means 12, and a second end 26 adapted to engage a lower coupling element 28 of the stance-phase control means 12.
- the piston and cylinder assembly 20 is further defined as having a piston linkage assembly 30 having a first end 31 mounted to the upper coupling element 24.
- the piston and cylinder assembly 20 further includes a piston rod 32 having a first end 34 that is adapted to engage the piston linkage assembly 30 and a second end 36 adapted to engage a piston 38.
- the second end 26 of the piston and cylinder assembly 20 has a cylinder bore 40 adapted to receive the piston 38 for dividing the cylinder bore 40 into first and second chambers 44 and 46 respectively.
- the second end 26 of the piston and cylinder assembly 20 may be positioned within the lower coupling element 28.
- the cylinder bore 40 has a second end 48 that accommodates a cylinder cap 50.
- the cylinder bore 40 also has a first orifice 52 in the first chamber 44 and a second orifice 54 in the second chamber 46.
- the first end 114 is adapted to engage the upper coupling element 108 wherein the perpendicular distance from the piston assembly 112 to the flexing axis 104 and the perpendicular distance from the piston assembly 1 12 and the control axis 106 are relatively equal when the artificial joint 102 articulates about the flexing axis 104 up to 65°.
- the swing-phase controller 100 further includes a cylinder assembly 1 18 having a first end 120 and a second end 122, the second end 122 is adapted to engage the lower coupling element 1 10 so that the second end 1 16 of the of the piston assembly 116 is adapted to engage the first end 120 of the cylinder assembly 1 18.
- the percentages of difference between dit A and dc A offsets through angles 0 to 65° are set out.
- the differences between d KA and dc A offsets can vary from 0% to as much as 70% during knee flexion.
- the relationship between the swing-phase control means 18 and the control axis 16 and the flexing axis 14, as set out in the description above still limits wear and preserves the stance-phase function.
- the offsets often remain relatively equal.
- the d ⁇ offset is greater than the dc A offset resulting in the engagement of the locking mechanism 206 in the artificial joint 10.
- the resistance to flexion is minimal as the air is becoming compressed. However once the air becomes compressed, the air provides greater resistance. This increased resistance is desired at higher flexion angles to limit the amount of heel-rise.
- the air in the pneumatic cylinder is compressed and provides a high level of resistance to limit heel-rise.
- the d KA offset and dcA offset are essentially equal and the locking mechanism 206 will disengage therefore eliminating wear.
- the CI KA offset is greater than the dc A offset, which results in the internal extension moment to be generated at the control axis 16.
- the creation of this moment eliminates wear in the artificial joint 10 as the locking mechanism 206 disengages as discussed above.
- the dsA and dcA offsets are essentially equal and this ensures that approximately no moment is generated at the control axis 16 and the locking mechanism 206 will engage as is appropriate.
- valves 58 Flow restrictions in the manifold 56 can be provided by valves 58 to resist the motion of the piston 38 and therefore the flexion and extension of the knee.
- resistance to flexion results from fluid in the lower chamber 46 being forced into the upper chamber 44.
- the resistance of knee flexion is altered. The same pertains to knee extension.
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- Health & Medical Sciences (AREA)
- Transplantation (AREA)
- Heart & Thoracic Surgery (AREA)
- Oral & Maxillofacial Surgery (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Cardiology (AREA)
- Vascular Medicine (AREA)
- Life Sciences & Earth Sciences (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Orthopedic Medicine & Surgery (AREA)
- Prostheses (AREA)
Abstract
An artificial joint including a stance-phase control means having a flexing axis and a control axis and a swing-phase control means adapted to engage the stance-phase control means. The perpendicular distance between the flexing axis and the swing-phase control means and the perpendicular distance between the control axis and the swing-phase control means are equal when the artificial joint rotates about the flexing axis up to 65°.
Description
Swing-Phase Controller with an Artificial Joint
Field of the Invention
This invention relates in general to a mechanism for controlling a joint's movement and more particularly to an artificial joint with a swing-phase controller.
Background of the Invention
Artificial joints generally require mechanisms to control their movement. For example an artificial knee joint or prosthetic joint will be prescribed for a person with a through-knee (TK) or an above-knee (AK) amputation, i.e. a person without a knee joint, shank or foot. The ability for the knee to bend or articulate during sitting, kneeling or ambulating is desirable. It is also desirable to have the ability to control the leg during the swing-phase of the gait when the person is walking or running. By improving control you also improve the look of the gait and make the gait look more natural. Finally the joint has to provide sufficient support to the person.
When standing or putting weight on the leg, as during the support-phase or stance-phase of the gait cycle it is undesirable for the artificial joint to bend uncontrollably as this will cause the amputee to fall. This is referred to as "stance- phase control". Amputees have some control during stance by the way they load the leg and how they use their remaining muscles at the hip. Alternatively, a prosthetist can align a prosthesis to be more or less stable by placing the knee joint axis behind the load bearing plane or load line. However, this tends not to produce ideal gait characteristics. While many different designs have been proposed, the majority of prosthetic knee joints are designed to address the issue of stance-phase control, i.e. keeping the knee from articulating when the prosthesis is supposed to be providing support. A prosthetic knee joint may have a built-in "locking" mechanism for this purpose.
The "swing-phase control" refers to the control of the joint's movement or articulation during the swing phase of the gait cycle to make the gait more efficient and more natural looking. Traditionally pneumatics or hydraulics are used in prosthetics to help control the swing-phase, as they are velocity dependent. Therefore as the gait velocity changes, the knee resistance changes. This is a beneficial attribute, because greater resistance is needed at higher velocities to provide adequate control of the joint. For example during walking, the air in a first chamber of a cylinder of a traditional pneumatic mechanism begins to compress as the knee begins to bend at the beginning of the swing-phase. Some of the air is displaced into a second chamber on the opposing side of the cylinder. A valve is used to control the flow rate and therefore the resistance. However the compression of the air in the first chamber also acts like a spring. The damping resistance and compressed air spring force act to slow the progression of knee flexion until the knee begins to extend. This acts to bring the leg forward quicker and limits the amount of heel-rise to normal levels. As the leg is extending, the air in the second chamber now compresses and before the knee fully extends, acts as a cushion (in the same manner as before) to slow the knee extension. This prevents the leg from slamming into the extended position (referred to as terminal impact). A hydraulic mechanism works in a similar manner but does not provide a spring force as the fluid is incompressible.
Prior art artificial joints have addressed some of the noted issues for both stance and swing-phase control. For example, many knees utilize hydraulic mechanisms to provide stance/swing-phase control including those described in US patents 5,376,137, 6,658,540 Bl and 6,652,585 B2. These devices address how the hydraulic mechanism is controlled to provide very high resistance to flexion during stance, and lower resistances to flexion and extension during swing. However the prior art does not address a swing-phase controller that efficiently functions within an artificial joint having a dual axis (knee flexion axis and control axis) stance-phase controller.
Thus a swing-phase controller with an artificial joint which controls the swing-phase of the joint through a large range of motion, is light weight, compact, low cost, produces more efficient and natural looking gait, can be used in other applications such as orthotic and robotic, decreases wear on other components in the artificial joint, and does not interfere with the stance-phase mechanism of the artificial joint is desirable.
Summary of the Invention
An object of one aspect of the present invention is to provide an improved swing-phase controller for an artificial joint in combination with a dual axis stance- phase controller.
In accordance with one aspect of the present invention there is provided an artificial joint including a stance-phase control means having a flexing axis and a control axis and a swing-phase control means adapted to engage the stance-phase control means. This engagement results in the perpendicular distance between the flexing axis and the swing-phase control means and the perpendicular distance between the control axis and the swing-phase control means being relatively equal when the artificial joint articulates about the flexing axis up to 65°.
Conveniently, the swing-phase control means includes a piston and cylinder assembly that has a first end adapted to engage an upper coupling element of the stance-phase control means, and a second end adapted to engage a lower coupling element of the stance-phase control means.
Preferably, the piston and cylinder assembly has a piston linkage assembly at the first end of the stance-phase control means so that the perpendicular distance from the piston linkage assembly to the flexing axis and the perpendicular distance from the piston linkage assembly and the control axis are relatively equal when the artificial joint articulates about the flexing axis up to 65°.
- A -
In accordance with another aspect of the present invention there is provided a swing-phase controller for an artificial joint having a flexing axis, a control axis, an upper coupling element, and a lower coupling element, where the swing-phase controller includes a piston assembly having a first end and a second end. The first end is adapted to engage the upper coupling element wherein the perpendicular distance from the piston assembly to the flexing axis and the perpendicular distance from the piston assembly and the control axis are relatively equal when the artificial joint articulates about the flexing axis up to 65°. The swing-phase controller further includes a cylinder assembly having a first end and a second end. The second end is adapted to engage the lower coupling element so that the second end of the piston assembly is adapted to engage the first end of the cylinder assembly.
Conveniently both the artificial joint with the stance-phase controller and the swing-phase controller, and the swing-phase controller on its own may be either hydraulic or pneumatic assemblies and applied to prosthetic, orthotic or robotic applications.
Advantages of the present invention are an artificial joint that can control the swing-phase of the joint through a large range of motion up to 65°, is light-weight, compact, low cost, provides for a more efficient and natural looking gait for the user, can be used in a variety applications such as prosthetic, orthotic and robotic, eliminates or decreases wear on the locking mechanism and the upper coupling element of the artificial joint as it does not interfere with these mechanisms, eliminates or reduces improper engagement of other components in the joint, and provides improved support which reduces a wobbly effect.
Brief Description of the Drawings
A detailed description of the preferred embodiments is provided herein below by way of example only and with reference to the following drawings, in which:
Figure 1 in a perspective view, illustrates an artificial joint in accordance with a preferred embodiment of the present invention;
Figure 2 in a side view, illustrates the artificial joint of Figure 1.
Figure 3 in an exploded view, illustrates the artificial joint of Figure 1.
Figure 4 in a partially sectioned view, illustrates the artificial joint of Figure
2.
Figures 5a, b and c in side views, illustrate the artificial joint of Figure 1 and the perpendicular distance between the piston linkage and both the flexing axis and the control axis.
Figure 6 in a perspective view, illustrates the swing-phase controller in accordance with another preferred embodiment of the present invention.
Figure 7 in a side view, illustrates the artificial joint of Figure 6.
Figure 8 in an exploded view, illustrates the artificial joint of Figure 6.
Figure 9 in a partially sectioned view, illustrates the artificial joint of Figure
7.
Figure 10a in a side view, illustrates a prior art artificial joint.
Figures 10b and c in side views, illustrate the artificial joint of Figure 1 and the activation of the biased compensation element.
Figures 1 Ia and b in side views, illustrate the swing-phase controller relative to the control axis and knee axis in another preferred embodiment of the present invention.
Figures l ie, and d in schematic views, illustrate the offset distances from the piston linkages to the knee axis and control axis.
In the drawings, preferred embodiments of the invention are illustrated by way of example. It is to be expressly understood that the description and drawings
are only for the purpose of illustration and as an aid to understanding, and are not intended as a definition of the limits of the invention.
Detailed Description of the Preferred Embodiment
Referring to Figures 1 and 2, there is illustrated in perspective and side views, an artificial joint 10 in accordance with a preferred embodiment of the present invention. The artificial joint 10 includes a stance-phase control means 12 having a flexing axis 14 and a control axis 16 and a swing-phase control means 18 adapted to engage the stance-phase control means 12. The perpendicular distance between the flexing axis 14 and the swing-phase control means 18 and the perpendicular distance between the control axis 16 and the swing-phase control means 18 are relatively equal when the artificial joint 10 articulates about the flexing axis 14 up to 65°.
The swing-phase control means 18 further includes a piston and cylinder assembly 20 that is adapted to engage the stance-phase control means 12. The piston and cylinder assembly 20 has a first end 22 that is adapted to engage an upper coupling element 24 of the stance-phase control means 12, and a second end 26 adapted to engage a lower coupling element 28 of the stance-phase control means 12. The piston and cylinder assembly 20 is further defined as having a piston linkage assembly 30 having a first end 31 mounted to the upper coupling element 24. As illustrated in Figures 5a-c, the perpendicular distance therefore from the piston linkage assembly 30 to the flexing axis 14 and the perpendicular distance from the piston linkage assembly 30 and the control axis 16 are relatively equal when the artificial joint 10 rotates about the flexing axis 14 up to 65°.
Referring to Figures 3 and 4 the piston and cylinder assembly 20 further includes a piston rod 32 having a first end 34 that is adapted to engage the piston linkage assembly 30 and a second end 36 adapted to engage a piston 38. The second end 26 of the piston and cylinder assembly 20 has a cylinder bore 40 adapted to receive the piston 38 for dividing the cylinder bore 40 into first and second chambers 44 and 46 respectively. The second end 26 of the piston and cylinder assembly 20 may be positioned within the lower coupling element 28. The cylinder
bore 40 has a second end 48 that accommodates a cylinder cap 50. The cylinder bore 40 also has a first orifice 52 in the first chamber 44 and a second orifice 54 in the second chamber 46. The cylinder bore 40 has a first end 42 that has a concentrically positioned small bore 64. A bearing 60 and seal 62 are fitted within the small bore 64 through which the piston rod 32 moves. The bearing 60 may be further defined as an axially long bearing for linearly constraining the piston rod 32. The bearing 60 positioned at the first end 42 of the cylinder bore 40, linearly contains the piston rod 32 thereby providing support to the piston linkage assembly 30 when side loads or non-axial loads are placed on the piston linkage assembly 30.
The positioning of the piston linkage assembly 30 also allows for the piston linkage assembly 30 to accommodate flexing angles of 150°, for example when the artificial joint 10 is in a kneeling or sitting position (Figure 5c). This degree of flexion is not as frequent as the typical degree of flexion for walking, which does not generally exceed 65°. Furthermore as the frequency and the velocities exhibited during kneeling and sitting are low, the wear on the artificial joint 10 is minimal.
The piston and cylinder assembly 20 further comprises a manifold 56 having a series of valves and channels 58 which allow for communication between the first and second chambers, 44 and 46 via the first and second orifices 52 and 54. The manifold 56 may be mounted to the cylinder bore 40 within the lower coupling element 28. The piston cylinder assembly 20 may either be hydraulic or pneumatic.
Referring to Figures 10b and c the stance-phase control means 12 is further defined as having an adjustable force transfer linkage assembly 200 having a first end 202 adapted to engage a latching or locking mechanism 206 and a second end 204 adapted to engage the lower coupling element 28. The second end 204 of the adjustable force transfer linkage assembly 200 is further defined as an elastomeric portion 208 configured to be positioned on either side of the piston rod 32, so that the piston rod 32 can move freely during the operation of the artificial joint 10, yet the elastomeric portion 208 may sit flat against the lower coupling element 28. The first end 202 of the adjustable transfer linkage assembly 200 is a biased compensation element 210 adapted to engage the latching mechanism 206. The
biased compensation element 210 may be a wedge 212 that is positioned or activated by a spring 214 for example.
Figure 10a illustrates prior art artificial joints that do not include a biased compensation element which produces a gap at the lower coupling element 28 and a wobble in the joint. Figures 10b and c illustrate the wedge 212 positioned by the spring 214 thereby changing the length of the force transfer linkage assembly 200. The spring 214 therefore ensures that the wedge 212 fits snugly between the lower coupling element 28 and the latching mechanism 206. The positioning of the wedge 212 during loading of the artificial joint 10, when the artificial joint 10 is locked, helps to decrease a wobbly effect caused by unresisted flexion/extension about the control axis 16. Specifically the wedge 212 compensates for changes in tolerance in the artificial joint 10 due to manufacturing or wear. This compensation results in an improved gait and more natural gait during the swing and stance-phases when the artificial joint 10 is incorporated into a knee joint for example.
Referring to Figures 6 and 7 in perspective and side views there is illustrated a swing-phase controller 100 for an artificial joint 102 in accordance with another preferred embodiment of the present invention. The swing-phase controller 100 for an artificial joint 102 having a stance-phase control means 103 with a flexing axis 104, a control axis 106, an upper coupling element 108, and a lower coupling element 110, where the swing-phase controller 100 has a piston assembly 1 12 having a first end 114 and a second end 1 16. The first end 114 is adapted to engage the upper coupling element 108 wherein the perpendicular distance from the piston assembly 112 to the flexing axis 104 and the perpendicular distance from the piston assembly 1 12 and the control axis 106 are relatively equal when the artificial joint 102 articulates about the flexing axis 104 up to 65°. The swing-phase controller 100 further includes a cylinder assembly 1 18 having a first end 120 and a second end 122, the second end 122 is adapted to engage the lower coupling element 1 10 so that the second end 1 16 of the of the piston assembly 116 is adapted to engage the first end 120 of the cylinder assembly 1 18.
Referring to Figures 8 and 9 the piston assembly 1 12 has a piston linkage 124 having a first end 126 adapted to engage the upper coupling element 108, and a second end 128 adapted to engage a first end 130 of a piston rod 132, the piston rod 132 having a second end 134 with a piston 136. The cylinder assembly 1 18 has a wall 138 surrounding a defined cylinder bore 140 having a first end 142 adapted to receive the piston 136 for dividing the cylinder bore 140 into first and second chambers 144 and 146 respectively, and a second end 148 having a cylinder cap 150. The cylinder assembly 1 18 has a first orifice 152 through the wall 138 in the first chamber 144 and a second orifice 154 through the wall 138 in the second chamber 146. The first end 142 of the cylinder bore 140 further includes a concentrically positioned small bore 141 and further includes a bearing 156 and a seal 160 through which the piston rod 132 moves.
The cylinder assembly 118 further includes a manifold 162 having a series of valves and channels 164 which allows for communication between the first and second chambers 144 and 146 respectively via the first and second orifices 152 and
154. Both the piston and cylinder assemblies 112 and 118 may be either hydraulic or pneumatic.
The artificial joint 10 may be used in a variety of applications for example as a prosthetic, orthotic or robotic joint. The following describes the artificial joint 10 in operation in a prosthetic knee joint. In operation the knee joint should be controlled so that during weight bearing, the knee latching or locking mechanism 206 is inactive when the fore foot is loaded, or similarly, the knee lock is activated only when the rear and/or mid-region of the foot is loaded. During operation, the knee joint would normally collapse as the load line passes behind the flexing axis or knee axis 14 and causes a flexion moment at the knee axis 14. However, in the instant invention the inclusion of the control axis 16 provides the control, such that as long as there is a flexion moment at control axis 16, a locking mechanism 206 can be activated at knee axis 14. The user can therefore roll over the foot until the toe is loaded, at which point the person will apply a flexion moment at the hip via their muscles. The application of the flexion moment will cause the load line to pass posterior of the knee axis 14, but still be anterior of the control axis 16, therefore
causing an extension moment about control axis 16 and thereby deactivating the locking mechanism 206. Therefore the knee joint is able to bend and the swing- phase can be initiated.
Control of the articulation of a knee during the swing-phase is controlled by the swing-phase control means 18. The main purpose is to provide appropriate levels of resistance at the flexing or knee axis 14. By providing appropriate levels of resistance during the flexing movement there is improved timing of the swing-phase, lessened excessive heels rise during mid-swing-phase and decreased the terminal impact as the leg straightens out at the end of swing-phase. The inclusion of the swing-phase control means 18 makes the gait more efficient and more natural looking and reduces wear between the locking mechanism 206 and the upper coupling element 24.
The stance-phase control means 12 however, controls how the artificial knee joint locks, as well as how the latching or locking mechanism 206 is controlled. In general the locking of the artificial knee joint 10 may generally include the locking mechanism 206 such as a latch, plunger or lock. The acting torque or moment at the control axis 16 determines whether the latch or lock is engaged or disengaged and is a function of the loading of the prosthesis.
More specifically a flexion moment will cause lock engagement and an extension moment will cause lock disengagement. For example if the artificial joint
10 does not have a swing-phase control means 18, and the leg is swinging, no internal moment is generated at the flexing or knee axis 14. There is also essentially no internal moment generated at the control axis 16. With the inclusion of the swing-phase control means 18, a moment at the flexing or knee axis 14 is generated so as to provide the swing-phase control. The generation of this moment however, results in the generation of a second moment, slightly smaller in magnitude, about the control axis 16. It is this moment that can have potentially adverse effects on the engagement and disengagement of the stance-phase control means 12 and especially adverse effects on the wear of the locking mechanism 206. Specifically the sliding contact between the locking mechanism 206 or latch and upper coupling element 24
will result in wear of these mechanisms. If the force of contact can be reduced by disengaging the lock (i.e. an extension moment at the control axis 16) then the wear will be reduced on the locking mechanism 206 or latch and upper coupling member
24.
In operation, as resistance is applied at the flexing or knee axis 14 with the implementation of a swing-phase control means 18, the moment generated about the control axis 16 will cause the engagement or activation of stance-phase control means 12, namely the locking mechanism 206, thereby increasing wear between the locking mechanism 206 and the upper coupling element 24. The moment at the control axis 16 however is eliminated or does not adversely affect the locking mechanism 206 and the upper coupling element 24 when the perpendicular offset or distance of the piston linkage assembly 30 from the flexing or knee axis 14 di<A and control axis 16 dcA are relatively equal.
Referring to Table 1, the percentages of difference between ditA and dcA offsets through angles 0 to 65° are set out. The differences between dKA and dcA offsets can vary from 0% to as much as 70% during knee flexion. Despite the sometimes large percentage of difference at various points during the knee flexion, the relationship between the swing-phase control means 18 and the control axis 16 and the flexing axis 14, as set out in the description above, still limits wear and preserves the stance-phase function. However, for knee flexion specifically at 65°, which represents the flexion angle during walking, the offsets often remain relatively equal.
Table 1
Knee Angle (degrees) dKA (mm) dCA (mm) difference(%)
0 13.24 13.24 0
10 14.59 11.07 32
20 15.81 10.03 58
30 16.79 10.04 67
40 17.38 11 58
50 17.37 12.69 37
60 16.6 14.87 12
65 15.88 16.06 -1
Furthermore Figures 5a-c illustrate that the CIKA and dcA offsets are not always constant as a function of knee flexion/extension. The following describes the interaction within the artificial joint at various points of flexion and that relationship to the dKA and dcA offsets:
During Knee Flexion:
Between 0-65°, the d^ offset is greater than the dcA offset resulting in the engagement of the locking mechanism 206 in the artificial joint 10. Normally there would be increased wear on the locking mechanism 206, however, during this range of the swing-phase, there is minimal resistance so the wear on the artificial joint 10 is minimal. Furthermore when the artificial joint 10 utilizes a pneumatic cylinder, for 0-50° of flexion, the resistance to flexion is minimal as the air is becoming compressed. However once the air becomes compressed, the air provides greater resistance. This increased resistance is desired at higher flexion angles to limit the amount of heel-rise. At higher flexion angles, such as between 50-65°, the air in the pneumatic cylinder is compressed and provides a high level of resistance to limit heel-rise. At this juncture the dKA offset and dcA offset are essentially equal and the locking mechanism 206 will disengage therefore eliminating wear.
During Knee Extension:
During the majority of the return of the leg to the extension position, namely between 65 - 0°, the CIKA offset is greater than the dcA offset, which results in the internal extension moment to be generated at the control axis 16. The creation of this moment eliminates wear in the artificial joint 10 as the locking mechanism 206 disengages as discussed above. At full extension, the dsA and dcA offsets are essentially equal and this ensures that approximately no moment is generated at the control axis 16 and the locking mechanism 206 will engage as is appropriate.
Where the artificial joint 10 utilizes a hydraulic cylinder, there is usually low resistance during initial knee flexion, then increased resistance at later knee flexion to limit heel-rise, then low resistance during extension until just prior to full knee extension, and finally increased resistance to decelerate the leg and limit terminal impact at full knee extension. The hydraulic cylinder therefore functions in a similar manner to the pneumatic cylinder described above, and therefore provides improved function with the stance-phase control means.
Figures 1 Ia and b illustrate that the offset distances from the piston linkage assembly 30 and the cylinder bore 40 are relatively equal to one another when the artificial joint 10 articulates up to 65°. Furthermore Figures 1 la-d show the different positioning of the piston cylinder assemblies 20 relative the stance-phase control means 12.
Table 2 describes the relationship between offset distances and effect on lock/stance-phase controller function. It is generally true that during flexion a passive flexion resisting moment (or extension moment) is generated (i.e. the passive moment is always in the opposite direction). So if the knee is tending to flex, the moment is resisting flexion and therefore is acting in the opposite, extension direction. This works well for truly passive devices like a hydraulic cylinder. However, for a pneumatic cylinder, which acts in part like a spring as the air compresses, the moment may not always be opposite to the direction of motion. During heel-rise the leg is flexing it is being decelerated by a combination of damping moments caused by the flow of air and also the spring like force of the
compressed air. The leg finally stops and then begins to extend. The damping moment reverses direction, but the spring moment still acts in the same direction. If this spring moment is in excess of the passive damping moment, the swing-phase controller will actually be acting to accelerate the leg. Therefore an extension moment will be applied to the extending leg for a short amount of time.
Table 2
In operation the piston linkage assembly 30 of the swing-phase control means 18 transmits motion or forces from the upper coupling element 24 through the piston rod 32 and to the piston 38. The piston rod 32 slides through first end 42 of the cylinder bore 40 through the bearing 60 and a dynamic seal 62 located in the small bore 64. The piston 38, which can incorporate a dynamic seal, separates the space within the cylinder bore 40 into the first and second chambers, 44 and 46, or the upper and lower chambers. When the piston rod 32 is moved, the first and second orifices 52 and 54 in each of the chambers 44 and 46, and the network of channels and valves 58 found in a manifold 56, allow for the flow of fluid (air or oil) from one chamber to the other to be controlled. Flow restrictions in the manifold 56 can be provided by valves 58 to resist the motion of the piston 38 and therefore the flexion and extension of the knee. When the knee is being flexed, resistance to flexion results from fluid in the lower chamber 46 being forced into the upper
chamber 44. By changing the ease of flow, the resistance of knee flexion is altered. The same pertains to knee extension.
Other variations and modifications of the invention are possible. All such modifications or variations are believed to be within the sphere and scope of the invention as defined by the claims appended hereto.
Claims
1. An artificial joint comprising:
(a) a stance-phase control means having a flexing axis and a control axis, and
(b) a swing-phase control means adapted to engage the stance-phase control means;
wherein the perpendicular distance between the flexing axis and the swing- phase control means and the perpendicular distance between the control axis and the swing-phase control means are relatively equal when the artificial joint articulates about the flexing axis up to 65°.
2. An artificial joint as claimed in claim 1 wherein the swing-phase control means comprises a piston and cylinder assembly adapted to engage the stance-phase control means.
3. An artificial joint as claimed in claim 2 wherein the piston and cylinder assembly has a first end adapted to engage an upper coupling element of the stance-phase control means, and a second end adapted to engage a lower coupling element of the stance-phase control means.
4. An artificial joint as claimed in claim 3 wherein the piston and cylinder assembly has a piston linkage assembly at the first end of the piston cylinder assembly.
5. An artificial joint as claimed in claim 4 wherein the perpendicular distance from the piston linkage assembly to the flexing axis and the perpendicular distance from the piston linkage assembly and the control axis are equal when the artificial joint rotates about the flexing axis up to 65°.
6. An artificial joint as claimed in claim 4 wherein the piston and cylinder assembly further comprises a piston rod having a first end adapted to engage the piston linkage assembly and a second end adapted to engage a piston.
7. An artificial joint as claimed in claim 6 wherein the second end of the piston and cylinder assembly has a cylinder bore having a first end adapted to receive the piston for dividing the cylinder bore into first and second chambers.
8. An artificial joint as claimed in claim 7 wherein the cylinder bore has a second end having a cylinder cap and a first orifice in the first chamber and a second orifice in the second chamber.
9. An artificial joint as claimed in claim 8 wherein the piston and cylinder assembly further comprises a manifold having a series of valves and channels allowing for communication between the first and second chambers via the first and second orifices.
10. An artificial joint as claimed in claim 1 wherein the stance-phase control means further comprises an adjustable force transfer linkage assembly having a first end with a biased compensation element adapted to engage a latching mechanism, and a second end having an elastomeric portion adapted to engage the lower coupling element wherein the activation of the biased compensation element adjusts the length of the adjustable force transfer linkage assembly.
1 1. An artificial joint as claimed in claim 2 wherein the piston and cylinder assembly is hydraulic or pneumatic.
12. A swing-phase controller for an artificial joint having a stance-phase control means with a flexing axis, a control axis, an upper coupling element, and a lower coupling element, the swing-phase controller comprising:
(a) a piston assembly having a first end and a second end, the first end adapted to engage the upper coupling element wherein the peφendicular distance from the piston assembly to the flexing axis and the perpendicular distance from the piston assembly and the control axis are relatively equal when the artificial joint articulates about the flexing axis up to 65°; and
(b) a cylinder assembly having a first end and a second end, the second end adapted to engage the lower coupling element,
wherein the second end of the of the piston assembly is adapted to engage the first end of the cylinder assembly.
13. A swing-phase controller for an artificial joint as claimed in claim 12 wherein the piston assembly has a piston linkage having a first end adapted to engage the upper coupling element, and a second end adapted to engage a first end of a piston rod, the piston rod having a second end with a piston.
14. A swing-phase controller for an artificial joint as claimed in claim 13 wherein the cylinder assembly has a wall surrounding a defined cylinder bore having a first end adapted to receive the piston for dividing the cylinder bore into first and second chambers, and a second end having a cylinder cap.
15. A swing-phase controller for an artificial joint as claimed in claim 14 wherein the cylinder assembly has a first orifice through the wall in the first chamber and a second orifice through the wall in the second chamber.
16. A swing-phase controller for an artificial joint as claimed in claim 14 wherein the first end of the cylinder bore further comprises a bearing and seal through which the piston rod moves.
17. A swing-phase controller for an artificial joint as claimed in claim 15 further comprising a manifold adapted to engage the cylinder assembly, the manifold having a series of valves and channels allowing for communication between the first and second chambers via the first and second orifices.
18. A swing-phase controller for an artificial joint as claimed in claim 14 wherein the first end of the cylinder bore further comprises a bearing and seal through which the piston rod moves.
19. A swing-phase controller for an artificial joint as claimed in claim 12 wherein the piston and cylinder assemblies are hydraulic or pneumatic.
20. An artificial joint as claimed in claim 1 used as prosthetic, orthotic or robotic joint.
21. A swing-phase controller as claimed in claim 12 used in a prosthetic, orthotic or robotic joint.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/989,192 US7909885B2 (en) | 2005-07-22 | 2006-07-21 | Swing-phase controller with an artificial joint |
CA2615994A CA2615994C (en) | 2005-07-22 | 2006-07-21 | Swing-phase controller with an artificial joint |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US70148705P | 2005-07-22 | 2005-07-22 | |
US60/701,487 | 2005-07-22 |
Publications (1)
Publication Number | Publication Date |
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WO2007009240A1 true WO2007009240A1 (en) | 2007-01-25 |
Family
ID=37668398
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/CA2006/001181 WO2007009240A1 (en) | 2005-07-22 | 2006-07-21 | Swing-phase controller with an artificial joint |
Country Status (3)
Country | Link |
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US (1) | US7909885B2 (en) |
CA (1) | CA2615994C (en) |
WO (1) | WO2007009240A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2008064462A1 (en) | 2006-11-30 | 2008-06-05 | Bloorview Kids Rehab | Artificial joint with locking mechanism |
GB2493441A (en) * | 2011-07-29 | 2013-02-06 | Blatchford Products Ltd | Lower limb prosthesis with knee joint |
US10576624B2 (en) | 2014-10-28 | 2020-03-03 | Thk Co., Ltd. | Rotational driving mechanism in a robot |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7981164B1 (en) * | 2009-07-07 | 2011-07-19 | Schultz Michael W | Knee prosthesis |
US7985264B2 (en) * | 2009-07-22 | 2011-07-26 | Chia-Pao Cheng | Cushion structure of artificial knee joint |
US10405997B2 (en) | 2015-05-05 | 2019-09-10 | Massachusetts Institute Of Technology | Passive artificial knee |
WO2018222997A1 (en) | 2017-06-02 | 2018-12-06 | Massachusetts Institute Of Technology | Locking and damping mechanism for a prosthetic knee joint |
EP4003240A1 (en) | 2019-07-30 | 2022-06-01 | College Park Industries, Inc. | Hydraulic prosthetic knee with resistance change mechanism at hyperextension |
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US5133773A (en) * | 1988-03-25 | 1992-07-28 | Kabushiki Kaisha Kobe Seiko Sho | Teaching playback swing-phase-controlled above-knee prosthesis |
US5376137A (en) * | 1991-03-14 | 1994-12-27 | Chas. A. Blatchford & Sons Limited | Artificial leg with hydraulic knee flexion resistance |
US5904721A (en) * | 1995-06-09 | 1999-05-18 | Proteval | Prosthetic component with pneumatic device for knee articulation |
US20050015156A1 (en) * | 2003-07-17 | 2005-01-20 | Yuichi Hikichi | Above-knee prosthesis with variable resistance knee joint |
US7044983B1 (en) * | 2003-07-24 | 2006-05-16 | Chia Pao Cheng | Positioning and buffering device for artificial knee joint |
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US6658540B1 (en) * | 2000-03-31 | 2003-12-02 | Hewlett-Packard Development Company, L.P. | Method for transaction command ordering in a remote data replication system |
US6652585B2 (en) * | 2001-02-28 | 2003-11-25 | Sdgi Holdings, Inc. | Flexible spine stabilization system |
US6997959B2 (en) * | 2003-08-01 | 2006-02-14 | Chien-Liang Chen | Multi-functional artifical knee joint |
-
2006
- 2006-07-21 WO PCT/CA2006/001181 patent/WO2007009240A1/en active Application Filing
- 2006-07-21 CA CA2615994A patent/CA2615994C/en not_active Expired - Fee Related
- 2006-07-21 US US11/989,192 patent/US7909885B2/en not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
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US5133773A (en) * | 1988-03-25 | 1992-07-28 | Kabushiki Kaisha Kobe Seiko Sho | Teaching playback swing-phase-controlled above-knee prosthesis |
US5376137A (en) * | 1991-03-14 | 1994-12-27 | Chas. A. Blatchford & Sons Limited | Artificial leg with hydraulic knee flexion resistance |
US5904721A (en) * | 1995-06-09 | 1999-05-18 | Proteval | Prosthetic component with pneumatic device for knee articulation |
US20050015156A1 (en) * | 2003-07-17 | 2005-01-20 | Yuichi Hikichi | Above-knee prosthesis with variable resistance knee joint |
US7044983B1 (en) * | 2003-07-24 | 2006-05-16 | Chia Pao Cheng | Positioning and buffering device for artificial knee joint |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2008064462A1 (en) | 2006-11-30 | 2008-06-05 | Bloorview Kids Rehab | Artificial joint with locking mechanism |
EP2091472A1 (en) * | 2006-11-30 | 2009-08-26 | Bloorview Kids Rehab | Artificial joint with locking mechanism |
EP2091472A4 (en) * | 2006-11-30 | 2014-05-21 | Bloorview Kids Rehab | Artificial joint with locking mechanism |
GB2493441A (en) * | 2011-07-29 | 2013-02-06 | Blatchford Products Ltd | Lower limb prosthesis with knee joint |
GB2493441B (en) * | 2011-07-29 | 2017-03-29 | Blatchford Products Ltd | Leg prosthesis |
US10576624B2 (en) | 2014-10-28 | 2020-03-03 | Thk Co., Ltd. | Rotational driving mechanism in a robot |
DE112015004892B4 (en) | 2014-10-28 | 2020-08-06 | Thk Co., Ltd. | Rotary drive mechanism in a robot |
Also Published As
Publication number | Publication date |
---|---|
US7909885B2 (en) | 2011-03-22 |
CA2615994A1 (en) | 2007-01-25 |
US20090088867A1 (en) | 2009-04-02 |
CA2615994C (en) | 2013-06-04 |
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