# Patent

## Title
Leg apparatus

## Abstract

A leg support exoskeleton is strapped on as wearable device to support its user during squatting. The exoskeleton includes a knee joint connected to a first line and a second link, which is configured to allow flexion and extension motion between the first link and the second link. A force generator has a first end that is rotatably connected to the first link. A constraining mechanism is connected to the second link and has at least two operational positions. In a first operational position, the second end of the force generator engages the constraining mechanism, where the first link and the second link flex relative to each other. In a second operational position, the second end of the force generator does not engage the constraining mechanism; the first link and the second link are free to flex and extend relative to each other.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. patent application 62/185,185, filed Jun. 26, 2015, which is incorporated by reference along with all other references cited in this application.


BACKGROUND OF THE INVENTION
This invention relates to the field of exoskeletons, and in particular exoskeletons for human legs.
Human beings have two legs to walk, run, jump, squat, and kick, which are all very human activities. The legs give mobility, and two-legged mobility gives a person a sense of well being, which wheel chairs and the like cannot replace. Thus, when a person is disabled or loses his or her mobility in some way, this has devastating consequences on the person's quality of life. Exoskeletons can be used to restore some mobility, but existing exoskeletons have shortcomings.
Therefore, there is a need for an improved exoskeleton, and in particular, a leg support exoskeleton to support a person during squatting.
BRIEF SUMMARY OF THE INVENTION
A leg support exoskeleton is strapped on as wearable device to support its user during squatting. The exoskeleton includes a knee joint connected to a first line and a second link, which is configured to allow flexion and extension motion between the first link and the second link. A force generator has a first end that is rotatably connected to the first link. A constraining mechanism is connected to the second link and has at least two operational positions. In a first operational position, the second end of the force generator engages the constraining mechanism, where the first link and the second link flex relative to each other. In a second operational position, the second end of the force generator does not engage the constraining mechanism; the first link and the second link are free to flex and extend relative to each other.
In an implementation, an exoskeleton leg apparatus is configured to be coupled to a lower extremity of a person. The apparatus includes: A knee joint is connected to a first link and a second link and is configured to allow flexion and extension motion between the first link and the second link. A force generator, where the first end of the force generator is rotatably connected to the first link. A constraining mechanism is connected to the second link having least two operational positions. When the constraining mechanism is moved into its first operational position, the second end of the force generator engages the constraining mechanism, when the first link and the second link flex relative to each other. When the constraining mechanism is in its second operational position the second end of the force generator does not engage the constraining mechanism and the first link and the second link are free to flex and extend relative to each other.
In various implementations, the force generator can be a gas spring, compression spring, coil spring, leaf spring, air spring, tensile, or spring, or any combination of these. The first link is configured to move in unison with the person's thigh and the second link is configured to move in unison with a person's shank. The second link can be configured to move in unison with the person's thigh and the first link is configured to move in unison with a person's shank.
The constraining mechanism can include an indentation in the second link and an indentation filler connected to the second link having at least two operational positions. When the indentation filler is moved into its first operational position, the indentation is not occupied by the indentation filler and the second end of the force generator engages the indentation, only when the first link and the second link flex relative to each other. When the indentation filler is in its second operational position, the indentation is occupied by the indentation filler and the second end of the force generator does not engage the indentation and the first link and the second link are free to flex and extend relative to each other.
The constraining mechanism can include a pawl connected to the second link having at least two operational positions. When the pawl moves into its first operational position, the second end of the force generator engages to the pawl, only when the second link and the first link flex relative to each other. When the pawl moves into its second operational position, the second end of the force generator does not engage to the pawl and the first link and the second link are free to flex and extend relative to each other. The pawl can be rotatably coupled to the second link.
The constraining mechanism can be moved by the person into the operational positions. The exoskeleton leg can further include a manual tab having at least two positions and operable by the person or user. The manual tab moves the constraining mechanism to the first operational position when the person moves the tab to its first position. The manual tab moves the constraining mechanism to the second operational position when the person moves the tab to its second position.
The manual tab slides on the second link and has at least two positions relative to the second link. The manual tab can include a magnet where the magnetic force moves the constraining mechanism between positions of the constraining mechanism.
The exoskeleton leg apparatus can include a triggering mechanism capable of automatically moving the constraining mechanism into the two operational positions. The triggering mechanism moves the constraining mechanism to the first operational position when the human leg is in contact with the ground. The triggering mechanism moves the constraining mechanism to the second operational position when the human leg is not in contact with the ground.
The exoskeleton leg apparatus can include a triggering mechanism capable of automatically moving the constraining mechanism into the two operational positions. The triggering mechanism includes: A transmission line, capable of transmitting motion and force, connected to the constraining mechanism on its first end and a stance detector on its second end. A stance detector coupled to the transmission line from its second end, where the stance detector detects if the person's shoe is in contact with the ground. A return spring mounted on second link connected to the transmission line. When the exoskeleton leg is in contact with the ground, the stance detector moves the constraining mechanism to its first operational position through the transmission line. When the exoskeleton leg is not in contact with the ground, the return spring moves the constraining mechanism to its second operational position.
The stance detector can be located inside the user's shoe, bottom of the person shoe, or in person's shoe sole, or any combination of these. The transmission line can be a rope, wire rope, twine, thread, nylon rope, chain, or rod, or any combination of these. The transmission line is a hydraulic hose containing hydraulic fluid and the stance detector comprises a reservoir containing hydraulic fluid. When the apparatus is in contact with the ground, the pressure generated in the hydraulic fluid due to contact of the exoskeleton leg with the ground moves the constraining mechanism to its first operational position through the hydraulic hose. When the apparatus is not in contact with the ground, the return spring moves the constraining mechanism to its second operational position.
The exoskeleton leg apparatus can include a triggering mechanism capable of automatically moving the constraining mechanism into the two operational positions. The triggering mechanism includes: An actuator capable of moving the constraining mechanism into the two operational positions. A stance sensor capable of detecting if the person's shoe is in contact with the ground by generating a first electric signal. When the apparatus is contacting the ground, the stance sensor generates a first electric signal and consequently the actuator moves the constraining mechanism to its first operational position. When the apparatus is not contacting the ground, the stance sensor generates a second electric signal and consequently the actuator moves the constraining mechanism to its second operational position.
The exoskeleton leg apparatus can include a triggering mechanism capable of automatically moving the constraining mechanism into the two operational positions. The triggering mechanism includes: An actuator capable of moving the constraining mechanism into the two operational positions. A stance sensor capable of detecting if the person's shoe is in contact with the ground by generating a first electric signal. At least one contralateral stance sensor coupled to the person's contralateral leg capable of detecting if the person's contralateral shoe is in contact with the ground by generating a contralateral electric stance signal. When the apparatus is contacting the ground, the stance sensor generates a first electric signal and the actuator moves the constraining mechanism to its first operational position if the contralateral electric stance signal presents the contralateral leg is on the ground. When the apparatus is not contacting the ground, the stance sensor generates a second electric signal and consequently the actuator moves the constraining mechanism to its second operational position.
The stance sensor can be located inside the user's shoe, outside the person shoe, or in person's shoe sole, or any combination of these. The stance sensor can be located inside the user's shoe, outside the person shoe, or in person's shoe sole, or any combination of these. The stance sensor can be is selected from a group consisting of strain gage sensors, pressure sensors, force sensors, piezoelectric force sensor, and force sensors based on force sensing resistors, and any combination of these. The stance sensor is selected from a group consisting of strain gage sensors, pressure sensors, force sensors, piezoelectric force sensor, and force sensors based on force sensing resistors, and any combination of these.
The actuator is selected from a group consisting of solenoids, linear motors, electric motors, servos, DC motors, voice coil actuators, piezoelectric actuators, spring loaded solenoids, and spring loaded motors, and any combination of these. The actuator is selected from a group consisting of solenoids, linear motors, electric motors, servos, DC motors, voice coil actuators, piezoelectric actuators, spring loaded solenoids, and spring loaded motors, and any combination of these.
A foot link mechanism is connected to the first link or the second link, where the foot link mechanism includes at least one foot connector configured to move in unison with the user's foot. The foot connector can be located at a bottom of the user's shoe, inside a cavity within the shoe sole, or inside user's shoe, or any combination of these.
The foot connector can quickly detach from user's shoe. The foot connector can quickly detach from the foot link mechanism. The first link can include a torque adjustment mechanism to adjust a desirable resisting torque. The torque adjustment mechanism can include a screw connected or fastened to the first end of the force generator and a nut where the rotation of the nut moves the screw and the end of the force generator.
In an implementation, an exoskeleton leg apparatus is configured to be connected to a lower extremity of a person. The apparatus includes: A thigh link configured to move in unison with the person's thigh. A shank link configured to move in unison with the person's shank. A knee joint connected to a shank link and a thigh link and configured to allow flexion and extension motion between the thigh link and the shank link. A force generator, where the first end of the force generator is rotatably connected to the shank link. A constraining mechanism connected to the thigh link having least two operational positions. A manual tab capable of moving the constraining mechanism between the operational positions and operable by the person. When the constraining mechanism is moved into its first operational position through the operation of the manual tab, the second end of the force generator engages the constraining mechanism when the thigh link and the shank link flex relative to each other.
When the constraining mechanism is moved into its second operational position through the operation of the manual tab, second end of the force generator does not engage the constraining mechanism and the shank link and the thigh link are free to flex and extend relative to each other.
In an implementation, an exoskeleton leg apparatus is configured to be connected to a lower extremity of a person. The apparatus includes: A thigh link configured to move in unison with the person's thigh. A shank link is configured to move in unison with the person's shank. A knee joint is connected to a shank link and a thigh link and is configured to allow flexion and extension motion between the thigh link and the shank link. A force generator, where the first end of the force generator is rotatably connected to the shank link. A constraining mechanism connected to the thigh link having at least two operational positions wherein in its first operation position the second end of the force generator engages the constraining mechanism when the shank link and the thigh link flex toward each other and in its second operational position the second end of the force generator does not engage the constraining mechanism and the shank link and the thigh link are free to flex and extend relative to each other. An actuator is capable of moving the constraining mechanism into the two operational positions. A stance sensor is capable of detecting if the person's shoe is in contact with the ground by generating a first electric signal.
When the apparatus is contacting the ground, the stance sensor generates a first electric signal and consequently the actuator moves the constraining mechanism to its first operational position. When the apparatus is not contacting the ground, the stance sensor generates a second electric signal and consequently the actuator moves the constraining mechanism to its second operational position.
Other objects, features, and advantages of the present invention will become apparent upon consideration of the following detailed description and the accompanying drawings, in which like reference designations represent like features throughout the figures.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an embodiment of an exoskeleton leg which is configured to be strapped on or otherwise connected to a lower extremity of a person.
FIG. 2 shows the exoskeleton leg without the person.
FIG. 3 shows an embodiment of an exoskeleton leg where a first link is configured to move in unison with a user's thigh and a second link is configured to move in unison with a user's shank.
FIG. 4 shows an embodiment of an exoskeleton leg where a first link is configured to move in unison with a user's shank and a second link is configured to move in unison with a user's thigh 204.
FIG. 5 shows an embodiment of a constraining mechanism.
FIG. 6 shows in operation when a moving tab is in its first position.
FIG. 7 shows an exoskeleton leg without a person.
FIG. 8 shows a first link moves a flexion relative to a second link.
FIG. 9 shows a first link moves a flexion relative to a second link.
FIG. 10 shows an exoskeleton leg where a constraining mechanism is in its second position where motion in flexion and an extension between the first link and second link relative to each other are free.
FIG. 11 shows an exoskeleton leg where a constraining mechanism is in its second position where motion flexion and an extension between the first link and second link relative to each other are free.
FIG. 12 shows another embodiment of a constraining mechanism.
FIG. 13 shows an embodiment of constraining mechanism in a first operating position.
FIG. 14 shows an embodiment of constraining mechanism in a second operating position.
FIG. 15 shows an embodiment where a moving tab is moved manually by person 200.
FIG. 16 shows an embodiment where a triggering mechanism is moved by a stance sensing module connected to the exoskeleton leg.
FIG. 17 shows an embodiment where the leg is off the ground and a stance sensing module triggers the second operational position of the constraining mechanism.
FIG. 18 shows a constraint mechanism is in a second operational position of the constraining mechanism.
FIG. 19 shows an embodiment where the leg is on the ground and a stance sensing module uses a transmission line to trigger the first operational position of the constraining mechanism.
FIG. 20 shows an embodiment where the leg is not on the ground and stance sensing module triggers the second operational position of the constraining mechanism.
FIG. 21 shows an embodiment where the leg is on the ground and a hydraulics stance detector triggers the first operational position of the constraining mechanism.
FIG. 22 shows an embodiment where the leg is on the ground and a triggering mechanism includes a stance sensor that is capable of generating a stance signal that triggers the first operational position of the constraining mechanism.
FIG. 23 shows an embodiment where a triggering mechanism includes a stance sensor and a contralateral stance sensor which a generate stance signal and a contralateral stance signal to trigger the operational position of the constraint mechanism.
FIG. 24 shows an embodiment where a foot connector can quickly detach from foot link mechanism.
FIG. 25 shows an embodiment of an exoskeleton leg where a foot link mechanism includes a first ankle link that is connected to a first link.
FIG. 26 shows an embodiment where a foot connector is located inside a user's shoe. The shoe has been removed from the image for clarity.
FIG. 27 shows an embodiment where a foot connector is located inside a cavity within shoe sole.
FIG. 28 shows an embodiment where a foot connector can quickly detach from a user's shoe.
FIG. 29 shows an embodiment where a foot connector can quickly detach from a foot link mechanism.
FIG. 30 shows an embodiment where a foot link mechanism can quickly detach from a first link.
FIG. 31 shows an embodiment where an exoskeleton leg includes a torque adjustment mechanism that can be used to change the supporting torque.



DETAILED DESCRIPTION OF THE INVENTION
Various embodiments of the invention include an exoskeleton leg that supports the user's leg and knee while squatting. A device according to the invention reduces leg muscle strain while squatting, but allows the user to walk freely without any interference. Various embodiments of the invention are described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown in the figures. These inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.
FIG. 1 shows an embodiment of exoskeleton leg 100 which is configured to be strapped on or otherwise connected or coupled to a lower extremity 202 of a person 200.
FIG. 2 shows exoskeleton leg 100 without person 200. Exoskeleton leg 100, in addition to other things, comprises: a first link 102 which, in one embodiment, is configured to move in unison with a user's thigh 204; a second link 104 which, in one embodiment, is configured to move in unison with a user's shank 206; a knee joint 106 positioned between first link 102 and second link 104 and is configured to allow flexion and extension between first link 102 and second link 104, where flexion is shown by arrow 120 where first link 102 gets close to second link 104 and extension is shown by arrow 118 where first link 102 gets farther away from second link 104; a force generator 108, wherein the first end 112 of force generator 108 is rotatably coupled to first link 102; a constraining mechanism 130 which is coupled to second link 104 having at least two operational positions (or modes); and a triggering mechanism 132 capable of moving constraining mechanism 130 into its two operational positions.
In operation, when constraining mechanism 130 is moved into its first operational position (or mode), second end 114 of force generator 108 gets rotatably latched to second link 104, only when first link 102 and second link 104 move in the first direction 120 relative to each other. This causes force generator 108 to create a force resisting motion in the first direction 120 of first link 102 relative to second link 104. It is important to realize that, in this first operational position, if first link 102 and second link 104 are moving in the second direction 118 relative to each other, constraining mechanism 130 does not constrain second end 114 of force generator 108 to the second link 104.
In operation when constraining mechanism 130 is moved into its second operational mode (or mode), second end 114 of force generator 108 is free to move and slide on second link 104 at all times (move unimpeded in both first direction 118 and second direction 120).
In summary, exoskeleton leg 100 provides assistance during squatting by moving into its first operational position, but allows for free and unconstrained walking by moving into its second operational position. In the first operational mode, force generator 108 provides a force to support the person during squatting; while in the second operational position force generator 108 does not interfere with the person's walking and the person is free to walk without any interference from exoskeleton leg 100.
FIG. 3 shows an embodiment of exoskeleton leg 100 which first link 102 is configured to move in unison with a user's shank 206. As shown in FIG. 3, in some embodiments, first link 102 and second link 103 are coupled to person's leg 208 with the help of braces 110.
FIG. 4 shows an embodiment of exoskeleton leg 100 which first link 102 is configured to move in unison with a user's thigh 204 and second link 104 is configured to move in unison with a user's shank 206.
FIG. 5 shows an embodiment of constraining mechanism 130. In this embodiment, constraining mechanism 130 comprises of an indentation 140 in second link 104 and an indentation filler 142 capable of moving relative to second link 104. In operation, when indentation filler 142 is in its first position as shown in FIG. 6, indentation 140 is not occupied by indentation filler 142. This means when first link 102 and second link 104 move in flexion 120 relative to each other, second end 114 of force generator 108 engages indentation 140. As first link 102 moves in flexion 120 relative to second link 104, the resisting force of force generator 108 resist the motion in flexion 120 of first link 102 relative to second link 104. This resisting force provides support for person 200 during squatting. This is shown in FIG. 6 through FIG. 9. However when indentation filler 142 is moved into its second position as shown in FIG. 5, indentation 140 is occupied by indentation filler 142. This means second end 114 of force generator 108 does not engage indentation 140 and therefore first link 102 and second link 104 are free to move in flexion 120 and extension 118 relative to each other. FIGS. 10 and 11 show exoskeleton leg 100 where constraining mechanism 130 is in its second position which motion in flexion 120 and extension 118 between the first link 102 and second link 104 relative to each other are free.
FIG. 12 shows another embodiment of constraining mechanism 130. In this embodiment, constraining mechanism 130 includes a pawl 152 on second link 104; and the triggering mechanism 132 comprises of a moving tab 154 capable of moving relative to second link 104. In operation, when moving tab 154 moves to its first position as shown in FIG. 12, pawl 152 moves into its first operational position and pawl 152 engages with a sliding ratchet 150 that is part of the second end 114 of force generator 108 such that the second end 114 of the force generator 108 engages to second link 104. See FIG. 13. This only occurs when first link 102 and second link 104 move in the first direction 120 relative to each other. However, when moving tab 154 moves into its second position and pawl 152 moves into its second operational position, pawl 152 does not engage with sliding ratchet 150 and the second end of said force generator does not latch onto said first link; and said first link and said second link are free to flex and extend relative to each other as shown in FIG. 14. FIG. 15 shows an embodiment where constraining mechanism 130 is moved by person 200 into its operational positions.
In some embodiments, exoskeleton leg 100 includes a manual tab 134 having at least two positions and operable by person 200. In some embodiments, as shown in FIG. 15, manual tab 134 slides on second link 104 and has at least two positions relative to second link 104. In operation, when person 200 moves manual tab 134 to its first position so that the constraining mechanism 130 is in its first operational position, force generator 108 engages the indentation 140 when person 200 squats. The engagement of forces generator 108 to indentation 140, causes a supporting force during squatting. This decreases the person's knee torque and provides support for person 200. When person 200 moves manual tab 134 to its second position so that the constraining mechanism 130 is in its second operational position, force generator 108 does not engage the indentation 140 when person 200 squats, walks, or doing any movements. This allows person 200 to move freely and unimpeded.
In some embodiments, manual tab 134 includes a magnet where the magnetic force moves constraining mechanism 130 between its two positions. This arrangement reduces the necessary linkage between manual tab 134 and constraining mechanism 130.
FIG. 16 shows an embodiment where exoskeleton leg 100 includes a triggering mechanism 132 capable of automatically moving constraining mechanism into two operational positions. Triggering mechanism 132 includes a stance detector 160 that is connected to exoskeleton leg 100. When stance detector 160 declares person's leg 208 is on the ground, stance detector 160 generates a stance signal 170 and moves constraining mechanism 130 to its first operational position. When constraining mechanism 130 is in its first operational position, force generator 108 is able to engage indentation 140, causing a supporting force during squatting. This decreases the person's knee torque and provides support for person 200. However, when stance detector 160 declares person's leg 208 is not on the ground, stance detector 160 moves constraining mechanism 130 to its second operational position. In this position, force generator 108 does not engage indentation 140 when person 200 squats, walks, or doing any movements. This allows person 200 to move freely and unimpeded. See FIGS. 17 and 18.
FIG. 19 shows an embodiment where a triggering mechanism 132 automatically moves constraining mechanism 130 into two operational positions. Triggering mechanism 132 includes of a stance detector 160 and a transmission line 162 that is connected to constraining mechanism 130 from one end and stance detector 160 from its second end. In operation, when stance detector 160 declares person's leg 208 is on the ground, transmission line 162 is pulled and indentation filler 142 is moved to its first position, allowing force generator 108 to engage indentation 140. However, when stance detector 160 declares person's leg 208 is not on the ground, as shown in FIG. 20, transmission line 162 is released and return spring 163 moves indentation filler 142 to its second position, not allowing force generator 108 to engage indentation 140. This allows person 200 to move freely and unimpeded.
In some embodiments, stance detector 160 is located inside user's shoe 212. In some embodiments, stance detector 160 is located on the bottom of user's shoe 212. In some embodiments, detector 160 is located in user's shoe sole. An ordinary person skilled in the art will recognize transmission line 162 can be selected from a set consisting of rope, wire rope, twine, thread, nylon rope, chain, and rod, and any combination of these.
FIG. 21 shows an embodiment where transmission line 162 is a hydraulic hose 300 containing hydraulic fluid and stance detector 160 includes a reservoir 302 filled with hydraulic fluid. In operation, when exoskeleton leg 100 is in contact with the ground, the pressure generated in hydraulic fluid due to contact of exoskeleton leg 100 with the ground moves constraining mechanism 130 to its first operational position through hydraulic hose 300 and when exoskeleton leg 100 is not in contact with the ground, return spring 163 moves constraining mechanism 130 to its second operational position.
In some embodiments as shown in FIG. 22, triggering mechanism 132 includes of a stance sensor 164 that is capable of generating a stance signal 170 when person's leg 208 is in the stance phase. Triggering mechanism 132 further includes of an actuator 166 connected or coupled to constraining mechanism 130 such that actuator 166 is capable of moving indentation filler 142 in and out of indentation 140.
In operation, when stance sensor 164 declares person's leg 208 is on the ground, actuator 166 moves indentation filler 142 away from indentation 140 allowing force generator 108 to engage indentation 140. This allows a supporting force to be generated during squatting. This decreases the person's knee torque and provides support for person 200. However, when stance sensor 160 declares the person's leg 208 is not on the ground, actuator 166 moves indentation filler 142 into indentation 140 preventing force generator 108 from engaging indentation 140. In this position, force generator 108 does not engage indentation 140 when person 200 squats, walks, or doing any movements. This allows person 200 to move freely and unimpeded.
FIG. 23 shows another embodiment. Triggering mechanism 132 includes a stance sensor 164 that is capable of generating a stance signal 170. Triggering mechanism 132 further includes an actuator 166 connected or coupled to constraining mechanism 130 such that actuator 166 is capable of moving indentation filler 142 in and out of indentation 140. Triggering mechanism 132 additionally includes a contralateral stance sensor 168 that is connected to the person's contralateral leg 210 whereas contralateral stance sensor 168 is capable of generating a contralateral stance signal 172 when person's contralateral leg 210 is contacting the ground. When stance sensor 164 and contralateral stance sensor 168 declare person's leg 208 and person's contralateral leg 210 are on the ground, actuator 166 moves indentation filler 142 away from indentation 140 allowing force generator 108 to engage indentation 140. This allows a supporting force to be generated during squatting. This decreases the person's knee torque and provides support for person 200. However, when either stance sensor 160 or contralateral stance sensor 168 declares the person's leg 208 or person's contralateral leg 210 is not on the ground, actuator 166 moves indentation filler 142 into indentation 140 preventing force generator 108 from engaging indentation 140. In this position, force generator 108 does not engage indentation 140 when person 200 squats, walks, or doing any movements. This allows person 200 to move freely and unimpeded.
In some embodiments, stance sensor 164 is located inside user's shoe 212. In some embodiments of the invention, stance sensor 164 is located on the bottom of user's shoe 212. In some embodiments of the invention, stance sensor 164 is located in user's shoe sole.
An ordinary person skilled in the art will recognize stance sensor 164 can be selected from a set consisting of strain gage sensors, pressure sensors, force sensors, piezoelectric force sensor, and force sensors based on force sensing resistors, and any combination of these. An ordinary person skilled in the art will recognize actuator 166 can be selected from a set consisting of solenoids, linear motors, electric motors, servos, DC motors, voice coil actuators, piezoelectric actuators, spring loaded solenoids, and spring loaded motors, and combination of these.
In some embodiments, exoskeleton leg 100 further includes a foot link mechanism 183. In some embodiments, as shown in FIG. 25, foot link mechanism 183 is connected or coupled to first link 102 when first link 102 is connected or coupled to user's shank 206. Of course in some embodiments, foot link mechanism 183 is connected or coupled to second link 104 when second link 104 is connected or coupled to user's shank 206 (not shown). A person having ordinary skill the art will recognize various mechanism with various degrees of freedom for foot link mechanism 183. FIG. 25 shows an embodiment of exoskeleton leg 100 that foot link mechanism 183 includes a first ankle link 180 that is coupled to second link 104. The second end of first ankle link 180 is rotatably coupled to a foot connector 182 that is configured to move in unison with the person's foot 214. In some embodiments of invention, as shown in FIG. 25 foot connector 182 is located at the bottom of said user's shoe 212. In some embodiments of invention, as shown in FIG. 26 foot connector 182 is located inside user's shoe 212. The shoe has been removed from the image for clarity. In some embodiments, as shown in FIG. 27 foot connector 182 is located inside cavity 184 within shoe sole.
As shown in FIG. 28, in some embodiments of invention, foot connector 182 can quickly detach from user's shoe 212. As shown in FIGS. 24 and 29, in some embodiments, foot connector 182 can quickly detach from foot link mechanism 183. As shown in FIG. 30, in some embodiments, foot link mechanism 183 can quickly detach from first link 102. Of course in some embodiments, foot link mechanism 183 can quickly detach from second link 104 when second link 104 is coupled to user's shank 206 (not shown).
FIG. 31 shows an embodiment of exoskeleton leg 100 that includes a torque adjustment mechanism 190 that can be used to change the supporting torque exoskeleton leg 100 is capable of providing. In this specific embodiment, torque adjustment mechanism 190 comprises of a torque adjustment dial 192 that can be rotated to change the location of first end 112 or second end 114 of force generator 108.
This description of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications. This description will enable others skilled in the art to best utilize and practice the invention in various embodiments and with various modifications as are suited to a particular use. The scope of the invention is defined by the following claims.

## Claims

1. A leg apparatus configured to be coupled to a lower extremity of a wearer, the leg apparatus comprising:
a first link;
a second link;
a knee joint, coupled to the first link and the second link and configured to allow flexion and extension motion between the first link and the second link;
a force generator, comprising a first end and a second end,
wherein the first end of the force generator is rotatably coupled to the first link; and

a constraining mechanism, coupled to the second link, the constraining mechanism having at least a first operational position and a second operational position, wherein:
when the constraining mechanism is moved into the first operational position, the second end of the force generator engages the constraining mechanism, when the first link and the second link flex relative to each other, and
when the constraining mechanism is in the second operational position, the second end of the force generator does not engage the constraining mechanism, and the first link and the second link are free flex and extend relative to each other.

2. The leg apparatus of claim 1, wherein the force generator is selected from the group consisting of a gas spring, a compression spring, a coil spring, a leaf spring, an air spring, a tensile spring, and any combination thereof.

3. The leg apparatus of claim 1,
wherein the first link is configured to move in unison with a thigh of the wearer, and
wherein the second link is configured to move in unison with a shank of the wearer.

4. The leg apparatus of claim 1,
wherein the second link is configured to move in unison with a thigh of the wearer, and
wherein the first link is configured to move in unison with a shank of the wearer.

5. The leg apparatus of claim 1,
wherein the constraining mechanism comprises:
an indentation; and
an indentation filler, coupled to the second link and having at least a first operational position and a second operational position,

wherein:
when the indentation filler is in the first operational position,
the indentation is not occupied by the indentation filler and
the second end of the force generator engages the indentation,
when the first link and the second link flex relative to each other, and

when the indentation filler is in the second operational position,
the indentation is occupied by the indentation filler,
the second end of the force generator does not engage the indentation, and
the first link and the second link are free to flex and extend relative to each other.

6. The leg apparatus of claim 1,
wherein the constraining mechanism comprises a pawl coupled to the second link,
the pawl having at least a first operational position and a second operational position,

wherein:
when the pawl is in the first operational position,
the second end of the force generator engages to the pawl, when
the second link and the first link flex relative to each other, and

when the pawl is in the second operational position,
the second end of the force generator does not engage to the pawl, and
the first link and the second link are free to flex and extend relative to each other.

7. The leg apparatus of claim 6, wherein the pawl is rotatably coupled to the second link.

8. The leg apparatus of claim 1, wherein the constraining mechanism is configured to be moved by the wearer between the first operational position and the second operational position.

9. The leg apparatus of claim 8, further comprises a manual tab having at least a first position and a second position and operable by the wearer, wherein:
the manual tab moves the constraining mechanism to the first operational position when the wearer moves the manual tab to the first position, and
the manual tab moves the constraining mechanism to the second operational position when the wearer moves the manual tab to the second position.

10. The leg apparatus of claim 9, wherein the manual tab is configured to slide on the second link between the first position and the second position relative to the second link.

11. The leg apparatus of claim 9,
wherein the manual tab comprises a magnet, and
wherein the magnet of the manual tab generates magnetic force configured to move the constraining mechanism between the first operational position and the second operational position of the constraining mechanism.

12. The leg apparatus of claim 1, further comprising a triggering mechanism configured to automatically move the constraining mechanism between the first operational position and the second operational position,
wherein the triggering mechanism is configured to move the constraining mechanism to the first operational position when a leg of the wearer is in contact with ground, and
wherein the triggering mechanism is configured to move the constraining mechanism to the second operational position when a leg of the wearer is not in contact with ground.

13. The leg apparatus of claim 1, further comprising a triggering mechanism configured to automatically move the constraining mechanism between the first operational position and the second operational position,
wherein the triggering mechanism comprises:
a stance detector, configured to detect if a shoe of the wearer is in contact with ground;
a transmission line, comprising a first end and a second end, the first end coupled to the constraining mechanism, and the second end coupled to a stance detector;
and
a return spring, mounted on the second link and coupled to the transmission line,

wherein:
when the leg apparatus is in contact with ground, the stance detector is configured to move the constraining mechanism to the first operational position through the transmission line, and
when the leg is not in contact with ground, the return spring is configured to move the constraining mechanism to the second operational position.

14. The leg apparatus of claim 13, wherein the stance detector is located in a location selected from the group consisting of inside the shoe of the wearer, at a bottom of the shoe of the wearer, in a sole of the shoe of the wearer, and any combination thereof.

15. The leg apparatus of claim 13, wherein the transmission line is selected from the group consisting of a rope, a wire rope, a twine, a thread, a nylon rope, a chain, a rod, and any combination thereof.

16. The leg apparatus of claim 13,
wherein the transmission line is a hydraulic hose containing hydraulic fluid,
wherein the stance detector comprises a reservoir containing the hydraulic fluid, and
wherein:
when the leg apparatus is in contact with ground, pressure generated in the hydraulic fluid due to contact of the leg apparatus with the ground is configured to move the constraining mechanism to the first operational position through the hydraulic hose, and
when the leg apparatus is not in contact with ground, the return spring is configured to move the constraining mechanism to the second operational position.

17. The leg apparatus of claim 1, further comprising a triggering mechanism configured to automatically move the constraining mechanism between the first operational position and the second operational position,
wherein the triggering mechanism comprises:
an actuator, configured to move the constraining mechanism between the first operational position and the second operational position; and
a stance sensor, configured to detect if a shoe of the wearer is in contact with ground and to generate a first electric signal when the shoe of the wearer is in contact with the ground and to generate a second electric signal when shoe of the wearer is not in contact with the ground;

wherein
when the leg apparatus is contacting ground, the stance sensor generates the first electric signal, and the actuator is configured to move the constraining mechanism to the first operational position, and
when the leg apparatus is not contacting ground, the stance sensor generates the second electric signal, and the actuator is configured to move the constraining mechanism to the second operational position.

18. The leg apparatus of claim 17, wherein the stance sensor is located in a location selected from the group consisting of an inside the shoe of the wearer, an outside the shoe of the wearer, in a sole of the shoe of the wearer, and any combination thereof.

19. The leg apparatus of claim 17, wherein the stance sensor is selected from the group consisting of a strain gage sensor, a pressure sensor, a force sensor, a piezoelectric force sensor, a force sensor based on force sensing resistors, and any combination thereof.

20. The leg apparatus of claim 17, wherein the actuator is selected from the group consisting of a solenoid, a linear motor, an electric motor, a servo, a DC motor, a voice coil actuator, a piezoelectric actuator, a spring loaded solenoid, spring loaded motor, and any combination thereof.

21. The leg apparatus of claim 1, further comprising a triggering mechanism configured to automatically move the constraining mechanism between the first operational position and the second operational position,
wherein the triggering mechanism comprises:
an actuator, configured to move the constraining mechanism between the first operational position and the second operational position;
a stance sensor, configured to detect if a shoe of the wearer is in contact with ground and to generate a first electric signal when the shoe of the wearer is in contact with the ground and to generate a second electric signal when the shoe of the wearer is not in contact with the ground; and
at least one contralateral stance sensor, coupled to a contralateral leg of the wearer and configured to detect if a contralateral shoe of the wearer is in contact with ground and to generate a first contralateral electric stance signal when the contralateral shoe of the wearer is in contact with the ground and to generate a second contralateral electric stance signal when the contralateral shoe of the wearer is not in contact with the ground;

wherein:
when the leg apparatus is contacting the ground, the stance sensor generates the first electric signal, and when the at least one contralateral stance sensor generates the first contralateral electric stance signal, the actuator is configured to move the constraining mechanism to the first operational position, and
when the leg apparatus is not contacting the ground, the stance sensor generates the second electric signal, and the actuator is configured to move the constraining mechanism to the second operational position.

22. The leg apparatus of claim 21, wherein the stance sensor is located in a location selected from the group consisting of an inside the shoe of the wearer, an outside the shoe of the wearer, in a sole of the shoe of the wearer, and any combination thereof.

23. The leg apparatus of claim 21, wherein the stance sensor is selected from the group consisting of a strain gage sensor, a pressure sensor, a force sensor, a piezoelectric force sensor, a force sensor based on force sensing resistors, and any combination thereof.

24. The leg apparatus of claim 21, wherein the actuator is selected from the group consisting of a solenoid, a linear motor, an electric motor, a servo, a DC motor, a voice coil actuator, a piezoelectric actuator, a spring loaded solenoid, a spring loaded motor, and any combination thereof.

25. The leg apparatus of claim 1, further comprising a foot link mechanism coupled to a link selected from the group consisting of the first link and the second link,
wherein the foot link mechanism comprises at least one foot connector configured to move in unison with a foot of the wearer.

26. The leg apparatus of claim 25, wherein the foot connector is configured to locate in a location selected from the group consisting of at a bottom of a shoe of the wearer, inside a cavity within a sole of the shoe of the wearer, inside the shoe of the wearer, and any combination thereof.

27. The leg apparatus of claim 26, wherein the foot connector is detachable from the shoe of the wearer or from the foot link mechanism.

28. The leg apparatus of claim 1,
wherein the first link comprises a torque adjustment mechanism to adjust a resisting torque,
wherein the torque adjustment mechanism comprises a screw coupled to the first end of the force generator and a nut, and
wherein rotation of the nut moves the screw and the first end of the force generator.

29. A leg apparatus configured to be coupled to a lower extremity of a wearer, the leg apparatus comprising:
a thigh link, configured to move in unison with a thigh of the wearer;
a shank link, configured to move in unison with a shank of the wearer;
a knee joint, coupled to the shank link and to the thigh link and configured to allow flexion and extension motion between the thigh link and the shank link;
a force generator, comprising a first end and a second end,
wherein the first end of the force generator is rotatably coupled to the shank link;

a constraining mechanism, coupled to the thigh link
the constraining mechanism having a first operational position and a second operational position; and

a manual tab, configured to move the constraining mechanism between the first operational position and the second operational positions, wherein:
when the constraining mechanism is in the first operational position, the second end of the force generator engages the constraining mechanism when the thigh link and the shank link are free flex relative to each other, and
when the constraining mechanism is in the second operational position, the second end of the force generator does not engage the constraining mechanism and the shank link and the thigh link are free to flex and extend relative to each other.

30. A leg apparatus configured to be coupled to a lower extremity of a wearer, the leg apparatus comprising:
a thigh link, configured to move in unison with a thigh of the wearer;
a shank link, configured to move in unison with a shank of the wearer;
a knee joint, coupled to the shank link and to the thigh link and configured to allow flexion and extension motion between the thigh link and the shank link;
a force generator, comprising a first end and a second end,
wherein the first end of the force generator is rotatably coupled to the shank link;

a constraining mechanism, coupled to the thigh link and having a first operational position and a second operational position wherein:
when the constraining mechanism is in the first operational position, the second end of the force generator engages the constraining mechanism when the shank link and the thigh link flex toward each other, and
when the constraining mechanism is in the second operational position, the second end of the force generator does not engage the constraining mechanism and the shank link and the thigh link are free to flex and extend relative to each other;

an actuator, configured to move the constraining mechanism between the first operational position and the second operational position; and
a stance sensor, configured to detect if a shoe of the wearer is in contact with ground and to generate a first electric signal when the shoe of the wearer is in contact with the ground and to generate a second electric signal when the shoe of the wearer is not in contact with the ground, wherein
when the leg apparatus is contacting the ground, the stance sensor generates the first electric signal, and the actuator moves the constraining mechanism to the first operational position, and
when the leg apparatus is not contacting the ground, the stance sensor generates the second electric signal, and the actuator moves the constraining mechanism to the second operational position.