Improved mechanical joints including small, bypassable single-spring or nested-spring coil clutches

Abstract

This specification relates to an improved mechanical joint comprising a small, bypassable single-spring or nested spring-type coil spring clutch ("BSorNWS clutch") that can be incorporated into various types of devices, apparatus, and systems, including prosthetic limbs. [Solution] One application of the BSorNWS clutch mechanical joint is a mechanical knee in a prosthesis. The BSorNWS clutch mechanical knee component used in a prosthesis further includes a thigh and lower leg attachment that rotates freely when the prosthesis is not loaded, but is restricted to rotating only in the extension direction of the lower leg when the BSorNWS clutch is activated by a load. The BSorNWS clutch mechanical knee includes additional components that adjust the load force required to bypass the BSorNWS clutch and slightly alleviate the rotational restriction imposed by the activation of the BSorNWS clutch.

Description

Technical Field

[0001] Cross - reference to related applications This application claims the benefit of Provisional Application No. 63 / 458,864, filed on April 12, 2023.

[0002] This disclosure relates to mechanical joints, particularly improved mechanical joints incorporating a single - spring or nested - spring wound - spring clutch that is small and bypassable.

Background Art

[0003] Mechanical joints connect two or more members and typically provide one or more types or modes of relative motion between the connected members. For example, the human knee is a complex biomechanical joint that connects the thigh and the lower leg and allows the thigh and the lower leg to rotate relative to each other. The human knee allows the lower leg to rotate approximately 180° relative to the thigh in a vertical plane that is approximately parallel to the sagittal plane and approximately perpendicular to the coronal plane, passing through the lower leg, the knee, and the thigh. It also allows limited rotation of the lower leg within a solid angle extending from the knee when the lower leg is perpendicular to the thigh, as well as slight extension, contraction, and compression of the leg. The human body includes many other types of biomechanical joints, such as multiple joints in the fingers and toes, the ball - and - socket joints of the hip and shoulder, the elbow joint, the wrist joint, and the ankle joint.

[0004] Mechanical joints are used in prosthetic limbs, robots, various types of machinery, and various types of mechanical and electromechanical devices, instruments, and systems. Mechanical joints are designed to provide a range of relative motion between members connected by the mechanical joint, and the relative motion can be constrained and controlled in various ways during the operation of devices and systems that incorporate mechanical joints. Mechanical joints can be controlled by external control devices and systems, internal components, and combinations of external control devices and systems and internal components. Control devices and systems are purely mechanical, including various types of guides and limiters, and may include mechanical, hydraulic, pneumatic, and electromechanical actuators, and often include control logic implemented with a processor and memory. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The design and control of mechanical joints involve various trade-offs and conflicting considerations. Simple mechanical control of mechanical joints is often cost-effective and robust, but may not provide the complex operating modes or functions required for specific applications. On the other hand, complex control devices and systems incorporating processors, memory, and various actuators can implement any complex control, including complex operating modes and functions, but they are costly to design and implement and may come with numerous failure modes and operational constraints, such as the need to power the control devices, systems, and various actuators.

[0006] The design and implementation of mechanical joints, or specific applications of mechanical joints, generally involve an optimization process that balances various trade-offs and competing considerations, resulting in a cost-effective mechanical joint that exhibits the desired operating modes and characteristics while maintaining the desired reliability and robustness. As an example, various types of mechanical knee joints are designed and implemented for use in prosthetics for amputees. Purely mechanical knee joints may be relatively inexpensive, but they may exhibit only a limited number of operating modes, and users may require extensive training to learn to walk using prosthetics incorporating purely mechanical knee joints. Purely mechanical knee joints may be relatively robust, but they may lack sufficient control flexibility to provide natural operating modes, and therefore may not provide users of prosthetics incorporating purely mechanical knee joints with an experience close to the safety and ease of use provided by a natural leg. In contrast, complex processor-controlled electromechanical knee joints may be able to more accurately simulate the operating modes of a natural knee, but they are subject to significant design and manufacturing costs and the constraint of requiring an external power supply. Therefore, the design, implementation, and manufacture of prosthetic limbs and other articulated prostheses involve a complex optimization process. Designers, vendors, and users of prosthetic limbs and other articulated prostheses are constantly seeking improved prostheses that incorporate improved mechanical knee joints and other improved mechanical joints that can facilitate the optimization process, reduce development and manufacturing costs, while simultaneously increasing reliability and robustness, and providing flexibility in operating modes and controls for manufacturing prostheses that more faithfully simulate natural limbs and other articulated anatomical features. Similarly, designers, vendors, and users of a wide variety of devices, instruments, and systems incorporating mechanical joints are constantly seeking improved mechanical joints to enhance the optimization of the design and manufacture of various devices, instruments, and systems. [Means for solving the problem]

[0007] This disclosure relates to an improved mechanical joint that comprises a small, bypassable single-spring or nested-spring coil clutch ("BSorNWS clutch"), which can be incorporated into a variety of devices, apparatus, and systems, including prosthetics. One application of the BSorNWS clutch mechanical joint is a mechanical knee joint in a prosthetic. The BSorNWS clutch mechanical knee component used in a prosthetic further includes a thigh and tibia attachment that rotates freely when the prosthetic is unloaded, but is constrained to rotate only in the tibia extension direction when a load acts on the BSorNWS clutch. The BSorNWS clutch mechanical knee joint includes additional components that adjust the load force required to bypass the BSorNWS clutch and slightly alleviate the rotational constraints imposed by the actuation of the BSorNWS clutch. [Brief explanation of the drawing]

[0008] [Figure 1] Figures 1A-C show the characteristics of the human gait cycle.

[0009] [Figure 2] Figure 2 illustrates the first problem encountered when using a passively rotatable mechanical joint as the mechanical knee joint of a mechanical prosthesis.

[0010] [Figure 3] Figure 3 illustrates a similar problem encountered when using a passive rotational linkage mechanism as a mechanical knee joint in a mechanical prosthesis, using the same illustrative conventions as in Figure 2.

[0011] [Figure 4A] Figure 4A shows the basic components of a simple, conceptual BSorNWS clutch mechanical joint from two different perspectives. [Figure 4B] Figure 4B shows the basic components of a simple, conceptual BSorNWS clutch mechanical joint from two different perspectives.

[0012] [Figure 5]Figure 5 shows the BSorNWS clutch mechanical joint assembled from the BSorNWS clutch mechanical joint components described above with reference to Figure 4A-B.

[0013] [Figure 6] Figure 6 shows two different diagrams of a BSorNWS clutch mechanical joint assembled from the BSorNWS clutch mechanical joint components described above with reference to Figures 4A-B, illustrating the state in which the BSorNWS is released or bypassed due to the reduction of the load on the BSorNWS clutch mechanical joint.

[0014] [Figure 7A] Figure 7A shows a simplified conceptual representation of the BSorNWS clutch mechanical joint, used as a mechanical knee joint in a prosthetic leg, at various different positions and time points in the gait cycle shown in Figure 1A. [Figure 7B] Figure 7B shows a simplified, conceptual representation of the BSorNWS clutch mechanical joint, used as a mechanical knee joint in a prosthetic leg, at various different positions and points in time during the gait cycle shown in Figure 1A. [Figure 7C] Figure 7C shows a simplified, conceptual representation of the BSorNWS clutch mechanical joint, used as a mechanical knee joint in a prosthetic leg, at various different positions and points in time during the gait cycle shown in Figure 1A. [Figure 7D] Figure 7D shows a simplified, conceptual representation of the BSorNWS clutch mechanical joint, used as a mechanical knee joint in a prosthetic leg, at various different positions and points in time during the gait cycle shown in Figure 1A. [Figure 7E] Figure 7E shows a simplified, conceptual representation of the BSorNWS clutch mechanical joint, used as a mechanical knee joint in a prosthetic leg, at various different positions and points in time during the gait cycle shown in Figure 1A.

[0015] [Figure 8] Figure 8 shows an exploded view of the WSC used in WSC mechanical joints.

[0016] [Figure 9] Figure 9 shows the WSC mechanical joint in a perspective view.

[0017] [Figure 10] Figures 10A - B show one embodiment of an inverted single - spring wound spring ( "inverted SSWS").

[0018] [Figure 11] Figures 11A - D show one embodiment of the BSorNWS clutch mechanical joint according to the present disclosure, incorporated into a BSorNWS clutch prosthetic leg.

[0019] [Figure 12] Figure 12 shows this alternative bypass mechanism.

[0020] [Figure 13] Figure 13 shows one embodiment of a flexion prevention override mechanism that allows for a slight controlled flexion of the BSorNWS clutch mechanical joint.

[0021] [Figure 14] Figure 14 shows another improvement incorporated into the BSorNWS clutch mechanical joint according to the present disclosure.

[0022] [Figure 15] Figure 15 shows a nested - spring wound spring ( "NSWS") and a BSorNWS clutch including the NSWS.

[0023] [Figure 16A] Figure 16A shows an alternative flexion prevention override mechanism that allows the lower leg attachment to rotate slightly in the flexion direction relative to the thigh attachment when a load is applied to the BSorNWS clutch mechanical joint. [Figure 16B] Figure 16B shows an alternative flexion prevention override mechanism that allows the lower leg attachment to rotate slightly in the flexion direction relative to the thigh attachment when a load is applied to the BSorNWS clutch mechanical joint. [Figure 16C] Figure 16C shows an alternative anti-flexion override mechanism that allows the lower leg attachment to rotate slightly in the flexion direction relative to the thigh attachment when a load is applied to the BSorNWS clutch mechanical joint.

[0024] [Figure 17] Figure 17 shows an alternative embodiment of the lower leg attachment that moves relative to the housing depending on whether or not a load is applied to the lower leg attachment, as described above.

[0025] [Figure 18A] Figure 18A shows yet another alternative embodiment of the lower leg attachment. [Figure 18B] Figure 18B shows yet another alternative embodiment of the lower leg attachment. [Figure 18C] Figure 18C shows yet another alternative embodiment of the lower leg attachment.

[0026] [Figure 19A] Figure 19A shows the alternative bypass mechanism. [Figure 19B] Figure 19B shows the alternative bypass mechanism. [Modes for carrying out the invention]

[0027] This document relates to mechanical joints incorporating bypassable single-spring or nested-spring coil spring clutches ("BSorNWS clutches"), and to the use of mechanical joints incorporating BSorNWS clutches as mechanical knee joints in prosthetics. The following first subsection discusses the human gait cycle. The second subsection discusses the desired motion characteristics of the mechanical knee joint. The third subsection discusses a simple and conceptual BSorNWS clutch mechanical joint, illustrating the features and motion characteristics of the BSorNWS clutch mechanical joint of this disclosure. The fourth subsection discusses one embodiment of the BSorNWS clutch mechanical joint of this disclosure. The final subsection discusses various alternative embodiments of the BSorNWS clutch mechanical joint of this disclosure. Walking cycle

[0028] Figures 1A-C illustrate the characteristics of the human gait cycle. Figure 1A shows the human gait cycle. Figure 1A shows a stick figure representation of a leg, including the first representation 102, at various points in time and positions along the horizontal plane 104 within the gait cycle. The gait cycle begins at the first position and time 111 and ends at the final position and time 118, immediately preceding the start position and time 119 of the next gait cycle. Assuming that the leg representation in Figure 1A represents the user's left leg, the user's right leg follows the same gait cycle, but the right leg's gait cycle is temporally staggered relative to the left leg's gait cycle. For example, if the left leg is at position and time 111, which is the start of the left leg's gait cycle, the right leg is at position and time 114, which is the middle of the right leg's gait cycle.

[0029] At position and time 111, the user's left leg is extended outward in the direction of walking, and the heel of the left foot is placed on a horizontal plane in front of the user's center of gravity. Until the heel of the user's left foot makes contact with the horizontal plane, the user's weight is fully supported by the right leg, and as the right leg flexes, the user's center of gravity moves forward of the position of the toes of the right foot. Next, in position and time sequence 112-114, as the user's center of gravity moves forward and the user's right leg bends further, the right leg swings forward out of the horizontal plane, as in position and time sequence 116-119, and the user's weight shifts to the left leg. Thus, the gait cycle of each leg is divided into a stance phase 120 and a swing phase 122. During the stance phase, the user's weight is fully transferred to the leg, and the user's center of gravity, which was initially behind the leg, moves in front of the leg, allowing the other leg to be lifted and swung forward during the swing phase. During the swing phase, the lower leg rotates counterclockwise relative to the upper leg in the direction shown in Figure 1A, extending forward in the direction of walking. This counterclockwise rotation is called "extension." During the stance phase, the lower leg rotates clockwise relative to the upper leg in the direction shown in Figure 1A. This clockwise rotation of the lower leg causes the user's weight to move forward from behind the leg to in front of the leg. This clockwise rotation is called "flexion."

[0030] Figures 1B-C show extension and flexion. In Figure 1B, the stick figure representation of leg 130 shows the lower leg bent backward relative to the thigh. The walking direction is from left to right, as in Figure 1A. The curved arrow 132 and the dashed lower leg 134 represent the lower leg rotating counterclockwise relative to the thigh. The final position of the lower leg after the counterclockwise rotation is shown by the dashed lower leg 134. This counterclockwise rotation represents the extension of the lower leg relative to the thigh, as described above. The knee can extend until the lower leg and thigh are parallel, forming an almost straight line through the knee. By extending the solid lower leg 136 to the position of the dashed lower leg 134 and simultaneously changing the orientation of the thigh 130, various leg positions and orientations, including the leg positions and orientations 138 and 140 shown in Figure 1B, can be achieved. Of course, when viewing the leg from the opposite side, where the walking direction is from right to left, extension of the lower leg relative to the thigh involves a clockwise rotation, not a counterclockwise rotation. Using the same illustrative convention as used in Figure 1B, Figure 1C shows flexion of the lower leg relative to the thigh. In the orientations shown in Figures 1A-C, flexion occurs due to a clockwise rotation of the lower leg relative to the thigh. However, when the walking direction changes 180° from right to left, flexion occurs due to a counterclockwise rotation of the lower leg relative to the thigh. The transition from position and time 111 to position and time 112 in Figure 1A is caused by a relatively slight flexion of the lower leg relative to the thigh, and the transition from position and time 112 to position and time 113 in Figure 1A represents extension of the lower leg relative to the thigh. In the gait cycle, flexion decreases the angle between the thigh and the lower leg, while extension increases the angle between the lower leg and the thigh. Desired mechanical knee joint motion characteristics

[0031] Amputees use prosthetics for walking and other activities. An ideal prosthesis would have the same weight and dimensions as a natural leg, be powered by an internal battery or other power source, require minimal charging, and be controlled by input from the user's nervous system. Unfortunately, an ideal prosthesis is not currently available and is not expected to become available in the near future. In fact, the various types of prosthetic knees used generally fail to provide both the range of relative movement between the thigh and lower leg of the prosthesis that occurs in a natural leg, and the advanced control functions necessary to achieve the movement characteristics of a natural leg. Currently available prosthetics include microprocessor-controlled electromechanical prostheses and mechanical prostheses. Microprocessor-controlled prostheses are often easier for users to master than mechanical prostheses. Microprocessor-controlled prostheses generally offer a wider range of movement modes and characteristics than mechanical prostheses, and function closer to a natural leg than mechanical prostheses. As a result of research, microprocessor-controlled prostheses that can be controlled by input from the user's nervous system are also being developed. However, microprocessor-controlled prostheses are generally very expensive and therefore unaffordable for many amputees who need them. They are often powered by batteries with relatively short charging intervals and are prone to various failures and malfunctions due to the complexity of their components. In contrast, mechanical prostheses are generally much less expensive, often more durable, and easier to manufacture, although they do not offer the wide range of operating modes and characteristics that microprocessor-controlled prostheses provide. In this and the following paragraphs, the term “mechanical joint” refers to a joint that is entirely or purely mechanical and does not have electronic, pneumatic, or hydraulic control subsystems or devices. The mechanical joints disclosed and claimed herein are purely or entirely mechanical joints that, when incorporated into prostheses, result in prostheses that are far less expensive and generally more robust and reliable than those with electronic, electromechanical, hydraulic, and / or mechanical-hydraulic control components and actuators. Furthermore, the mechanical joints disclosed and claimed herein offer a wider range of operating modes and characteristics than currently available mechanical prostheses.

[0032] The functions required of a mechanical knee joint used in a mechanical prosthesis can be inferred by referring to Figure 1A and considering the gait cycle described above. As mentioned above, the mechanical knee joint connects or links the thigh and lower leg and must be able to allow both extension and flexion of the lower leg. However, a mechanical joint that is only capable of passive rotation is insufficient to realize a usable prosthesis. Figure 2 illustrates the first problem that would be encountered if a mechanical joint capable of passive rotation were used as the mechanical knee joint in a mechanical prosthesis. Figure 2 shows a series of representations of a patient 202 wearing a prosthesis 204 walking from left to right. In representation 206, the patient's prosthesis is at or near the position or time 113 in Figure 1A. As the patient's center of gravity continues to move forward and the patient begins to lean forward to swing the left leg forward, as shown in representation 208, which corresponds to the position or time 114 in Figure 1A, the mechanical joint capable of passive rotation begins to fail and subsequently buckles, as shown in representations 210 and 212 in Figure 2. Therefore, while flexion of the prosthesis is necessary during the gait cycle or swing phase, flexion during the stance phase must be prevented to avoid buckling of the prosthesis and the resulting tripping or falling. Figure 3 illustrates a similar problem that occurs when a linkage mechanism capable of passive rotation is used as the mechanical knee of a mechanical prosthesis, using the same illustrative conventions as those used in Figure 2. This problem occurs earlier in the gait cycle than the problem shown in Figure 2, when the prosthesis is at the gait cycle position or time point 112 shown in Figure 1A. The user has not fully shifted their weight onto the prosthesis, but after full extension at the position or time point 111 in Figure 1A, the lower leg rotates slightly clockwise relative to the thigh. The prosthesis begins to collapse rather than re-extend to reach the position or time point 113. Therefore, the mechanical knee joint must prevent the lower leg from flexing significantly relative to the thigh at least at positions or times 112 and 114, allow controlled slight flexion at positions or times 111 and 113, and allow significant flexion at positions or times 115–117. The mechanical knee joint needs to allow the lower leg to extend freely relative to the thigh until the thigh and lower leg are nearly parallel during the swing phase of the gait cycle, as shown in position or time points 111, 113, and 119 in Figure 1A.In fact, due to the dynamics of the gait cycle, a mechanical knee joint only needs to prevent extension from continuing beyond the point where the thigh and lower leg are nearly parallel; otherwise, extension can be allowed at any point in the gait cycle.

[0033] There are many different methods for mechanically controlling a mechanical knee joint to limit flexion at appropriate times and positions during the gait cycle. In the methods used in the mechanical joints of this disclosure, each incorporating a bypassable single-spring or nested-spring coiled clutch ("BSorNWS clutch") (hereinafter referred to as the "BSorNWS clutch mechanical joint"), the control of flexion limitation during the gait cycle is based on whether the prosthesis, including the BSorNWS clutch mechanical joint (hereinafter referred to as the "BSorNWS clutch prosthesis"), supports a percentage or portion of the patient's weight that exceeds a threshold. For most of the swing phase of the gait cycle, as described above, the lower leg of the prosthesis is unloaded and the foot of the prosthesis is floating above the walking surface. This occurs at the position and time points 116-118 in Figure 1A. In this part of the gait cycle, there is no need to limit flexion; rather, flexion needs to be allowed by the mechanical knee joint in order to lift the foot off the walking surface. On the other hand, during the stance phase of the gait cycle, which occurs after position and time point 112 and before position and time point 114, flexion must be completely restricted to prevent buckling of the prosthesis, which can lead to tripping or falling, as described above. During this part of the stance phase of the gait cycle, the prosthesis supports all or most of the user's weight. Therefore, by detecting that the prosthesis is supporting a threshold percentage or portion of the user's weight, the mechanical control function or set of functions of the mechanical knee joint can restrict flexion during the appropriate part of the stance phase of the gait cycle and allow flexion during the appropriate part of the swing phase of the gait cycle.

[0034] Mechanical knee joints require several more nuanced motion characteristics. Firstly, mechanical knee joints should not exhibit abrupt mode or state transitions, for example, allowing slight flexion even though flexion is generally restricted during the stance phase of the gait cycle. For instance, as described above, when the heel of the prosthesis contacts the horizontal plane at position or time 111, slight flexion needs to be allowed as the prosthesis transitions through position and time 112 to a full weight-bearing state at position and time 113. Secondly, the force applied to control the flexion constraint needs to vary depending on the relative orientation of the lower leg and thigh to facilitate the transition from sitting to standing. In the disclosed embodiments, these additional motion characteristics are provided by additional mechanical features of the BSorNWS clutch mechanical joint according to this disclosure, which are described in later sections of this specification. Conceptual diagram of the BSoRNWS clutch mechanical joint related to this disclosure

[0035] This section of the Specified Description describes a simplified conceptual BSorNWS clutch mechanical joint with reference to Figures 4A to 7E. This simplified conceptual BSorNWS clutch mechanical joint is described and illustrated in order to briefly and clearly illustrate the basic components of the BSorNWS clutch mechanical joint according to the Disclosure and the operation of the BSorNWS clutch mechanical joint at various positions and times in the gait cycle as described above and shown in Figure 1A. Again, the BSorNWS clutch mechanical joint according to the Disclosure is a purely or entirely mechanical joint. The simplified conceptual BSorNWS clutch mechanical joint has not been implemented and is unlikely to be implemented in the future. This is because, aside from demonstrating the basic components and component functions of the BSorNWS clutch mechanical joint, there are no known applications for the simplified conceptual BSorNWS clutch mechanical joint, and it is highly likely that the simplified conceptual BSorNWS clutch mechanical joint is impossible or impractical to manufacture. The relative component sizes, component orientations, and other characteristics of the simplified and conceptual BSorNWS clutch mechanical joint may be exaggerated compared to the actual relative component sizes and component orientations of BSorNWS clutch mechanical joints implemented in real-world applications such as mechanical knees and mechanical prostheses.

[0036] Figures 4A-4B show the basic components of a simple, conceptual BSorNWS clutch mechanical joint from two different perspectives. The basic components are: (1) A thigh component 402 comprising a thigh attachment shaft 404 mounted on a cylindrical member 406 having an internal cylindrical friction surface 408; (2) A cylindrical housing 410 having a slot 412 for housing the thigh attachment shaft 404, with a tibia attachment shaft coupling 414 mounted on the thigh attachment shaft 404; (3) A reversing single-spring coil spring ("reversing SSWS") 416 with two small horizontal attachment mechanisms 418 and 420; (4) A tibia attachment shaft 422 slidably mounted within the tibia attachment shaft coupling 414 and including a bypass pin hole 424; (5) A bypass pin 426; and (6) A bypass linkage 428. The thigh attachment shaft 404 and the tibia attachment shaft 422 connect a simple conceptual BSorNWS clutch mechanical joint to the thigh and tibia members of the BSorNWS clutch prosthesis, respectively. By rotating the thigh component 402 within the cylindrical housing 410, extension and flexion of the BSorNWS clutch mechanical joint and the BSorNWS clutch prosthesis are enabled. The inverted SSWS 416 implements the BSorNWS clutch. The coil spring mounting mechanism 418 is attached to the opening 430 within the housing 410 and secures the inverted SSWS to the housing. The inverted SSWS is housed within the cylindrical member 406 of the thigh component 402, the thigh component is housed within the cylindrical housing 410, and the thigh mounting axis 404 protrudes outward through the slot 412 of the cylindrical housing 410. When the inverted SSWS expands outward relative to the cylindrical friction surface 408 of the cylindrical member 406 of the thigh component 402, the rotational direction of the cylindrical member 406 of the thigh component 402 relative to the cylindrical housing 410 is locked when a rotational force is applied; otherwise, the tibia mounting axis would rotate in the flexion direction relative to the thigh mounting axis. The bypass linkage 428 is rotatably mounted to the small mounting mechanism 420 of the reversible SSWS via a small cylindrical mechanism 432, and is also mounted to the bypass pin 426. The bypass pin 426 is rotatably mounted in the bypass pinhole 424 toward the distal end of the lower leg mounting shaft 422, which is slidably mounted within the lower leg mounting shaft coupling 414.When no load is applied to the BSorNWS clutch prosthesis, the lower leg mounting shaft 422 slides downward within the lower leg mounting shaft joint 414, pulling the bypass linkage 428 downward. From the viewpoint shown in Figure 4A, the end of the inverted SSWS rotates counterclockwise, tightening the inverted SSWS and releasing the cylindrical member 406 of the thigh component 402, which rotates freely within the cylindrical housing. When a load is applied to the BSorNWS clutch prosthesis, the lower leg mounting shaft 422 slides upward within the lower leg mounting shaft joint 414, and the inverted SSWS expands outward, allowing the thigh component 402 to contact the cylindrical housing 410. Thus, the lower leg mounting shaft 422 moves vertically within the lower leg mounting shaft joint 414 in response to the loading and unloading of the BSorNWS clutch prosthesis. This vertical movement of the lower leg mounting shaft 422 is converted into the unwinding or winding of the inverted SSWS 416, which activates and deactivates the BSorNWS clutch.

[0037] Figure 5 shows the BSorNWS clutch mechanical joint assembled from the BSorNWS clutch mechanical joint components described above, with reference to Figures 4A-B. In Figure 5, the BSorNWS clutch is activated, thereby preventing or restricting rotation of the lower leg in the flexion direction relative to the thigh attachment. When a load is applied to the BSorNWS clutch mechanical joint, the lower leg mounting shaft 422 moves upward and enters the lower leg mounting shaft coupling 414, moving the bypass linkage upward. As a result, the inverted SSWS is not tightened by the bypass linkage and expands, and the outer surface of the coil of the inverted SSWS is pressed against the inside of the friction surface of the cylindrical member 406 of the thigh component 402. As will be further explained below, the lower leg mounting shaft 422 is equipped with a spring within the lower leg mounting shaft coupling 414. When a load is applied to the BSorNWS clutch mechanical joint, the spring is compressed. When the load on the BSorNWS clutch mechanical joint is released, the spring's decompression pushes the lower leg mounting shaft 422 downward. The BSorNWS clutch is actuated by the load on the BSorNWS clutch mechanical joint, regardless of the rotational direction of the thigh component 402 and the thigh mounting shaft 404 within the cylindrical housing 410.

[0038] Figure 6 shows two different diagrams of the BSorNWS clutch mechanical joint assembled from the BSorNWS clutch mechanical joint components described above with reference to Figures 4A-B, illustrating the BSorNWS being released or bypassed due to the weight reduction of the BSorNWS clutch mechanical joint. In the first Figure 602 of the BSorNWS clutch mechanical joint, the thigh attachment axis 404 is rotated downward in slot 412 relative to the lower leg attachment axis 422. In the second Figure 604, the thigh attachment axis 404 is rotated upward in slot 412 relative to the position of the thigh attachment axis in Figure 602. When the BSorNWS clutch mechanical joint is incorporated into the BSorNWS clutch prosthesis, the orientation of the thigh attachment axis relative to the lower leg attachment axis in Figure 602 corresponds to a large flexion of the lower leg member relative to the thigh member of the BSorNWS clutch prosthesis. In contrast, the orientation of the thigh attachment axis relative to the lower leg attachment axis in Figure 604 corresponds to a full extension of the lower leg member relative to the thigh member of the BSorNWS clutch prosthesis. In both Figures 602 and 604 of Figure 6, the weight reduction of the BSorNWS clutch mechanical joint and the depressurization of the spring in the lower leg mounting shaft coupling 414, combined with gravity, push the lower leg mounting shaft 422 downward. The extended lower leg mounting shaft pulls the bypass linkage 428 downward, tightening the coil of the inverted SSWS so that the outer surface of the coil no longer contacts the inner friction surface 408 of the cylindrical member 406 of the thigh component. This releases the BSorNWS clutch, allowing the thigh mounting shaft to rotate freely relative to the lower leg mounting shaft 422 within an angular range from full flexion to full extension.

[0039] It should be noted that the large difference in the effective length of the lower leg mounting axis between the operating state of the BSorNWS clutch shown in Figure 5 and the released state of the BSorNWS clutch shown in Figure 6, and the 90° rotation of the coil spring mounting axis 420 and the cylindrical mechanism 432 from the position in Figure 5 to the position in Figure 6, are exaggerations of the amount of extension and contraction of the lower leg mounting axis and the movement of the bypass link in the actual implementation described later. As described above, the simple and conceptual BSorNWS clutch mechanical joint described and illustrated in this section of this specification is used to clearly illustrate the operation of the BSorNWS clutch mechanical joint when used as a mechanical knee joint in a mechanical prosthesis during the gait cycle described above, with reference to Figure 1A.

[0040] Figures 7A-E show simplified conceptual representations of the BSorNWS clutch mechanical joint used as the mechanical knee joint of a prosthesis at various positions and points in time during the gait cycle shown in Figure 1A. Each of Figures 7A-E shows the simplified conceptual BSorNWS clutch mechanical joint from two different viewpoints or perspectives. Figure 7A shows the simplified conceptual BSorNWS clutch mechanical joint in orientation and configuration at positions and points 111 and 119 of Figure 1A. At positions and points 111 and 119, the prosthesis has just been fully extended and lowered, the heel of the foot is in contact with the walking surface, the user's weight is beginning to be transferred to the prosthesis, and the prosthesis is partially loaded. The weight of the prosthesis exceeds the threshold level or weight required to activate the BSorNWS clutch, so the clutch activates and the rotation of the tibial attachment axis in the flexion direction relative to the femoral attachment axis is restricted. It should be noted that the lower leg mounting shaft 422 is pushed into the lower leg mounting shaft coupling 414, compressing the internal spring, and the inverting SSWS 460 expands and presses against the internal friction surface of the cylindrical member 406 of the thigh component. The long axes of the thigh mounting shaft and the lower leg mounting shaft are parallel.

[0041] Figure 7B shows a simplified conceptual diagram of the orientation and configuration of the BSorNWS clutch mechanical joint at the position and time 112 shown in Figure 1A. At position and time 112, the weight of the prosthesis has increased, far exceeding the weight threshold required to release the BSorNWS clutch. As a result, the clutch remains engaged, and rotation of the lower leg attachment axis relative to the thigh attachment axis in the flexion direction is restricted. However, the long axes of the thigh attachment axis and the lower leg attachment axis 422 are no longer parallel, as shown in Figure 7A. This is because a slight flexion has occurred, as is evident from the non-parallel orientation of the thigh attachment axis and the lower leg attachment axis at position and time 112. As previously mentioned, this slight flexion is made possible by additional features of the BSorNWS clutch mechanical joint that are not included in the simplified conceptual BSorNWS clutch mechanical joint shown in Figures 4A-7E, which will be discussed in the following subsection of this specification.

[0042] Figure 7C shows a simplified, conceptual orientation and configuration of the BSorNWS clutch mechanical joint at the position and time 113 of Figure 1A. At position and time 113, the weight of the prosthesis is at its maximum, and the degree of weight far exceeds the weight threshold required to release the BSorNWS clutch. As a result, the clutch remains engaged, and rotation of the lower leg mounting axis 422 relative to the thigh mounting axis 404 in the flexion direction is restricted. The long axes of the thigh mounting axis and the lower leg mounting axis are parallel again, as in Figure 7A.

[0043] Figure 7D shows the orientation and configuration of a simplified conceptual BSorNWS clutch mechanical joint at position 1A and time 114. At position and time 114, the weight of the prosthesis is at its maximum, and the degree of weight far exceeds the weight threshold required to release the BSorNWS clutch. As a result, the clutch remains engaged, and rotation of the lower leg attachment axis relative to the thigh attachment axis in the flexion direction is restricted. However, the long axes of the thigh attachment axis and the lower leg attachment axis are no longer parallel, as shown in Figure 7C, and the BSorNWS clutch mechanical joint flexes slightly again as the user's center of gravity moves forward from the BSorNWS clutch mechanical joint in preparation for the user to shift their weight to their natural leg. As previously mentioned, this slight flexion is made possible by additional features of the BSorNWS clutch mechanical joint that are not included in the simplified conceptual BSorNWS clutch mechanical joint shown in Figures 4A-7E.

[0044] Figure 7E shows a simplified conceptual orientation and configuration of the BSorNWS clutch mechanical joint at the position and time 115 of Figure 1A. At position and time 115, the user is preparing to lift the lower leg portion of the prosthesis, and has shifted most of the user's weight to the natural leg. The weight of the prosthesis is below the weight level or degree required to activate the BSorNWS clutch. As a result, the BSorNWS clutch is released, and the rotation of the lower leg mounting axis relative to the thigh mounting axis is no longer constrained, allowing the lower leg mounting axis and the lower leg portion of the prosthesis to rotate freely relative to the thigh mounting axis and the thigh portion of the prosthesis over an angular range from full flexion to full extension. Note that the lower leg mounting axis 422 extends outward from the lower leg mounting joint 414. In the simplified conceptual BSorNWS clutch mechanical joint, the BSorNWS clutch remains disengaged, and in position and time points 116–118 of Figure 1A, the lower leg mounting axis and the lower leg member of the prosthesis can rotate freely relative to the thigh mounting axis and the thigh member of the prosthesis, and the change in the degree of flexion when the lower leg mounting axis and the lower leg member of the prosthesis are swung forward with the lower leg member of the prosthesis suspended above the walking surface is relatively small. Finally, in the transition from position and time point 118 to position and time point 119 of Figure 1A, the lower leg mounting axis and the lower leg member of the prosthesis are swung forward to a fully extended state, the heel of the foot of the lower leg member is lowered to the walking surface, and then sufficient weight is transmitted to the lower leg mounting axis and the lower leg member of the prosthesis to reactivate the BSorNWS clutch, as shown in Figure 7A.

[0045] The BSorNWS clutch mechanical joint according to this disclosure, as shown in the simplified conceptual BSorNWS clutch mechanical joint shown in Figures 4A-7E, possesses many important features and characteristics that differ from those of the double-wound spring clutch ("WSC") mechanical joint already disclosed in U.S. Patent No. 11,020,247. Figure 8 shows an exploded view of a WSC used in a WSC mechanical joint. The WSC 802 is based on a double-wound spring from which two outward-facing helical coils 834 and 836 extend from a central band 838. In contrast, the BSorNWS clutch mechanical joint according to this disclosure is a BSorNWS clutch that includes only a single spring or two nested spring-type coil springs. As described in U.S. Patent No. 11,020,247, at the time of filing U.S. Patent No. 11,020,247, the inventors believed that a double-wound spring was necessary for the implementation of a mechanical knee joint: In single-coil springs, mechanical failures can lead to accidents. Using double-coil springs, while a single-coil spring failure does not result in loss of rotational restraint, the failure is clearly apparent to the operator, indicating that repair is necessary. Furthermore, the double-coil spring configuration symmetrically distributes load forces through a bidirectional, bypassable overrunning mechanical clutch, mitigating unbalanced stresses and potential failure modes. However, further research and development efforts have revealed that the single-spring coil spring clutch (SSWSC) and nested-spring coil spring clutch (NSWSC) described herein are highly reliable and offer many significant advantages over conventionally disclosed WSCs. Firstly, both SSWSCs and NSWSCs are smaller, making them easier to integrate into prosthetics. The improved miniaturization or reduction in volume of SSWSCs and NSWSCs compared to WSCs greatly facilitates hermetically sealing of BS or NWS clutch mechanical joints. SSWSCs and NSWSCs are more robust and reliable than WSCs, have lower manufacturing costs, and offer greater design flexibility. The single spring of an SSWSC is less expensive and easier to manufacture than the double coil spring of a WSC. Furthermore, alignment and adjustment of a BS or NWS clutch are easier than alignment and adjustment of a WSC with a double spring that mates to two different cylindrical surfaces, namely the cylindrical surfaces of two arbors 804 and 806. Due to the longer length of the double-wound spring, the width of the WSC is wider compared to the BSorNWS clutch, and the alignment tolerance of the double-wound spring within the WSC assembly is also smaller, increasing the number of parts that require alignment and precision manufacturing for the WSC to operate effectively. Both the WSC and SSWSC operate by selectively generating friction to suppress rotation of the lower leg restraint relative to the thigh restraint, but the increased friction associated with the two springs in the double-wound spring used in the WSC can cause unwanted frictional resistance during the transition between clutch engagement and disengagement, and the friction generated on two different surfaces by two different springs is prone to asymmetric braking force, uneven wear, difficulty in alignment, and other problems. As will be further discussed below, by selecting materials and designs suitable for the SSWSC, single springs have been found to be more reliable and robust than the double-wound springs in the WSC.

[0046] Another important difference between the reversing SSWS used in one embodiment of the BSorNWS clutch according to this disclosure and the double-wound spring used in the WSC is that, as shown in Figures 5 and 6, the reversing single-wound spring expands outward to press against the inner friction surface 408 of the cylindrical member 406 (see Figures 4A-4B), generating friction that prevents rotation, whereas the two springs of the WSC are tightly fastened to the cylindrical surfaces of the two arbors 804 and 806. Thus, the reversing SSWSC operates by the expansion or unwinding of the spring, while the WSC operates by the contraction or increased winding of the two double springs.

[0047] The WSC mechanical joint comprises a yoke 816 within a complex yoke assembly that includes a double-wound spring, two arbors, two arbor sleeves 808 and 810, two clutch pins 812 and 814, a cylindrical cam 878, a torque transmission pin 820, two flexible linkages 224 and 226, and other components. In contrast, the inverted SSWSC implementation of the BSorNWS clutch mechanical joint includes a housing, cylindrical members, lower and upper leg mounting shafts, a single-wound spring, and a bypass linkage, which differ from the components of the WSC mechanical joint and operate differently from the components of the WSC mechanical joint, as will be described in detail below. Therefore, the BSorNWS clutch differs from the WSC and operates differently, and the BSorNWS clutch mechanical joint differs from the WSC mechanical joint disclosed in U.S. Patent No. 11,020,247. Figure 8 includes numerous numerical labels not mentioned in the previous paragraph, which are described in U.S. Patent No. 11,020,247, which includes Figure 8 of this application as Figure 6.

[0048] Figure 9 shows a perspective view of the WSC mechanical joint. The WSC mechanical joint consists of a yoke assembly including a yoke 816, arbor sleeves 808 and 810, and the aforementioned internal components, and a lower leg block 828 that moves perpendicular to the yoke assembly depending on whether or not a load is applied to the lower leg of the prosthesis. Two flexible links 824 and 826 link the lower leg block 828 to the arbor sleeves 808 and 810. When the lower leg block moves downward relative to the yoke assembly, the load on the lower leg and lower leg block is reduced, causing the arbor sleeve to rotate counterclockwise from the viewpoint in Figure 9, which unwinds the two helical coils in the yoke assembly, releasing or disengaging the WSC and allowing the lower leg block to rotate freely relative to the yoke assembly. In contrast, as shown in Figure 5-6, in the BSorNWS clutch mechanical joint, the lower leg mounting shaft 422 is slidably mounted within the lower leg mounting shaft mounting portion 414 of the cylindrical housing 410 and remains firmly mounted within the lower leg mounting shaft mounting portion regardless of whether a load is being placed on the lower leg of the prosthesis incorporating the BSorNWS clutch mechanical joint. Therefore, the BSorNWS clutch mechanical joint is physically more stable during the gait cycle than the WSC mechanical joint, in which the two main components, the yoke assembly and the lower leg block, are separated from each other when there is no load being placed on the lower leg of the prosthesis incorporating the WSC mechanical joint. This is a further improvement and advantage that the BSorNWS clutch mechanical joint according to this disclosure has over the WSC mechanical joint. Numerous additional advantages and improvements incorporated in the BSorNWS clutch mechanical joint according to this disclosure will be described in detail in subsequent sections of this specification. Methods and Systems Related to This Disclosure

[0049] Figures 10A-10B show one embodiment of a reversing single-spring coil spring ("reversing SSWS") used in the BSorNWS clutch according to this disclosure. Figure 10A shows the reversing SSWS 1002 viewed from the side. Figure 10B shows the reversing SSWS 1002 mounted on a circular base plate 1004. The base plate is provided with a sprocket-like mechanism including a sprocket mechanism 1006 along its circumference, which engages with a corresponding mechanism on the inner surface of the housing, described later, to securely fix the base plate and the left end of the reversing SSWS to the housing. This is just one example of the various types of structural features and operating mechanisms that can be used to securely rotate and fix one end of the reversing SSWS to the housing. Note that since the coil of the SSWS is cut from a metal cylinder, it has a nearly rectangular cross-section and exhibits a locally flat surface with respect to the locally flat friction surface against which the coil is pressed when the BSorNWS clutch is operated.

[0050] The inverted SSWS according to this disclosure represents a significant improvement over the double-wound springs used in conventionally disclosed WSCs. The width of the coils varies along the length of the inverted SSWS. At the left end of the inverted SSWS, the first coil 1008 is the widest. The next two coils 1010 are shorter than the first coil, but still wide enough. Along the inverted SSWS, several even narrower coils 1012 follow, followed by the six narrowest coils 1014. The narrowest coils are called "taser coils." The friction between the flat outer surface of the coiled spring and the inner friction surface 408 of the cylindrical member 406 of the thigh component 402 (see Figure 4A-B) is proportional to the surface area of ​​the flat outer surface of the coiled spring. However, the flexibility of the coiled spring is inversely proportional to the width of the coiled spring. Therefore, the taser coil is significantly more flexible than the left-side wide coil of the inverted SSWS, but the friction generated when it conforms to the inner surface of the cylindrical member is less than that of the left-side wide coil of the inverted SSWS. When the BSorNWS clutch is activated by the unwinding of the inverted SSWS, and the outer surface of the coil is pressed against the inner friction surface of the cylindrical member, the more flexible taser coil conforms more easily to the inner surface of the cylindrical member and begins to generate friction first. Subsequently, the remaining coils work together with the inner friction surface of the cylindrical member to engage, and once engaged, they generate the frictional force necessary to prevent the lower leg attachment axis from rotating in the flexion direction relative to the thigh attachment axis. Thus, the taser coil provides relatively quick engagement and disengagement, but with less frictional resistance, and together with the variable-width coils, it provides quick engagement and disengagement of the clutch while minimizing frictional resistance within the BSorNWS clutch mechanical joint. Not only does the width of the coils change along the length of the improved inverted SSWS, but the pitch of the coils also changes along the length of the inverted SSWS. If each coil is considered an approximation of the cylindrical edge of a planar disk, the coil pitch is the angle between a vector perpendicular to the plane of the disk and the rotational symmetry axis of the inverted SSWS. According to this definition, the pitch of the narrowest coil 1014 is approximately 0°, while the pitch of the second coil from the left appears to be approximately 5°.Therefore, the improved inverting SSWS is an inverting SSWS with variable coil width and variable coil pitch, providing rapid engagement and disengagement of the inverting SSWS while minimizing frictional resistance during the activation and disengagement of the BSorNWS clutch.

[0051] Inverted SSWSs are less susceptible to residual stress and therefore must be manufactured from a metal alloy whose shape and / or dimensions do not change during the process of helically cutting a metal alloy cylinder to manufacture the inverted SSWS. In one embodiment, the coil spring is manufactured from 4340 high-tensile steel that has been heat-treated to maximize tensile strength.

[0052] Figures 11A-D show an example of an implementation of the BSorNWS clutch mechanical joint according to this disclosure, incorporated into a BSorNWS clutch prosthesis. Figure 11A shows a perspective view of the BSorNWS clutch mechanical joint. The BSorNWS clutch mechanical joint 1102 has a structure in which the housing and the lower leg mounting axial coupling 1104 are integrated. The upper part of the housing and the lower leg mounting axial coupling is equivalent to the cylindrical housing 410 of the simplified conceptual BSorNWS clutch mechanical joint shown in Figures 4A-B, and the lower part of the housing and the lower leg mounting axial coupling is equivalent to the lower leg mounting axial coupling 414 of the simplified conceptual BSorNWS clutch mechanical joint shown in Figures 4A-B. The standard inverted pyramidal mechanism 1106 corresponds to the thigh mounting shaft 404 of the simplified conceptual BSorNWS clutch mechanical joint shown in Figures 4A-B, and the tube clamp 1108 at the shaft end corresponds to the lower leg mounting shaft 422 of the simplified conceptual BSorNWS clutch mechanical joint shown in Figures 4A-B. Of course, the coil spring clutch is housed in the upper part of the housing and lower leg mounting shaft coupling combined. The implementation shown in Figure 11A is just one of many implementation examples using various mounting mechanisms for the lower leg and thigh, which include threads and corresponding threaded structures, various types of compression fitting mechanisms, and other mounting mechanisms. In the following parts of this specification, various types of thigh shafts and / or mounting mechanisms will be referred to as “thigh mounting sections,” and various types of lower leg shafts and / or mounting mechanisms will be referred to as “lower leg mounting sections.” The housing and lower leg mounting shaft coupling combined will be referred to as “housing.” As can be seen in Figure 11A, the BSorNWS clutch mechanical joint according to this disclosure is a practical and implementable mechanical joint that can be fully hermetically sealed and incorporated into a prosthetic leg, unlike the simple and conceptual BSorNWS clutch mechanical joint shown in Figures 4A-B. However, the BSorNWS clutch mechanical joint according to this disclosure operates in the same manner as the aforementioned simple and conceptual BSorNWS clutch mechanical joint shown in Figures 4A-B.

[0053] Figure 11B shows an implementation example of the BSorNWS clutch mechanical joint according to the present disclosure shown in Figure 11A, with a portion of the housing cut out to reveal a bypass mechanism that operates similarly to the bypass link mechanism of the simplified conceptual BSorNWS clutch mechanical joint shown in Figures 4A-B. The bypass mechanism includes a mounting arm 1110 attached to the axis of the lower leg attachment 1112 and a mounting bracket 1114 attached to the end of the inverted SSWS closest to the observer in the perspective view shown in Figure 11B. In the following description, this end of the inverted SSWS will be referred to as the “lower leg end” of the inverted SSWS. When the load on the prosthesis incorporating the BSorNWS clutch mechanical joint is reduced and the axis of the lower leg attachment 112 slides downward, the mounting axis of the bypass linkage moves downward, and the bypass linkage mounting bracket 1114 rotates clockwise around a rotation axis that coincides with the cylindrical axis in the view of Figure 11B. The end of the cylindrical axis 1116 is shown in Figure 11B. As the inverted SSWS rotates clockwise, it tightens the coil, releasing it from contact with the internal friction surface of the cylindrical member within the housing and disengaging the BSorNWS clutch. Due to the weight of the prosthesis incorporating the BSorNWS clutch mechanical joint, the axis of the lower leg attachment 112 slides upward, causing the bypass linkage attachment axis to move upward and the bypass linkage attachment bracket 1114 to rotate counterclockwise from the viewpoint in Figure 11B. As the inverted SSWS rotates counterclockwise, the coil is released and extends against the internal friction surface of the cylindrical member within the housing. This activates the BSorNWS clutch, preventing the lower leg attachment from rotating further counterclockwise relative to the thigh attachment, i.e., in the lower leg flexion direction.

[0054] Figure 11C shows an implementation example of the BSorNWS-clutch mechanical joint according to the present disclosure shown in Figure 11A, and by rotating it slightly around the vertical axis, a portion of the side of the upper housing 1118, which is not visible in Figure 11A, is made visible, and curves such as curve 1120 indicate the shape of the housing. Figure 11D shows an implementation example of the currently disclosed BSorNWS-clutch mechanical joint shown in Figure 11C, with the housing removed to reveal the axis of the lower leg attachment 112 and the base plate 1004 of the inverted SSWS. As described above, the sprocket-like mechanism on the outer edge of the base plate engages with the corresponding mechanism in the housing, rotating and fixing the housing end of the inverted SSWS closest to the observer in the perspective view shown in Figure 11D to the housing. In other words, the housing end of the inverted SSWS is coupled to the housing, and the lower leg end of the housing is attached to the axis of the lower leg attachment via a bypass mechanism. Similar to the simple conceptual BSorNWS-clutch mechanical joint shown in Figures 4A-B, the thigh attachment 1106 is rotatably fixed to a cylindrical member in the housing. When the BSorNWS clutch is activated, the cylindrical member and the thigh attachment cannot rotate in the flexion direction relative to the lower leg attachment. When the BSorNWS clutch is released, the cylindrical member and the thigh attachment can rotate freely in both the flexion and extension directions relative to the lower leg attachment.

[0055] Various alternative bypass mechanisms are possible for alternative implementations of the BSorNWS clutch mechanical joint. As an example, in the implementation shown in Figure 11B, the mounting bracket may be connected to the lower leg mounting axis via a flexible linkage such as a cord or wire, rather than to the mounting arm. The flexible linkage may be attached via a mechanical arm to the cylindrical shaft near the housing and the inverting SSWS, rather than to the attachment bracket. Figure 12 shows this alternative bypass mechanism. A perspective side view of the cylindrical member is shown in the center of Figure 12. A cross section 1204 of the side view is shown on the lower right side of Figure 12. End views 1206 and 1208 of the cylindrical member and the mechanism within the cylindrical member are shown on either side of the perspective side view. The mechanical arm 1210 is attached to one end of the cylindrical shaft, the other end 1212 of which is shown in end view 1208. The attached small mounting bracket 1216 is the cylindrical cylinder at the end of the inverting SSWS 1218. Section 1204 shows a mounting bracket 1216 attached to the end of the inverted SSWS 1218. In this embodiment, there may be a nested second inverted SSWS 1222 to which another mounting bracket 1222 is attached. The limitations of nested coil springs will be discussed further below.

[0056] As described in a preceding subsection of this specification, the mechanical knee joint should prevent the lower leg from flexing significantly relative to the thigh at positions or times 112 and 114 in the gait cycle shown in Figure 1A, allow controlled small flexions at positions or times 111 and 113 in the gait cycle shown in Figure 1A, and allow large flexions at positions or times 115–117 in the gait cycle shown in Figure 1A. Figure 13 shows one embodiment of a flexion-prevention override mechanism that allows control of small flexions in the BSorNWS clutch mechanical joint at positions or times 111 and 113 in the gait cycle shown in Figure 1A. Figure 13 shows a side view 1302 and a perspective view 1304 of the flexion-prevention override mechanism within the BSorNWS clutch mechanical joint. The mechanism includes a throttling 1306 fixed to a cylindrical member and fixed to the lower leg end of the inverted SSWS 1308–1310, and a compressible urethane spider 1312. When the BSorNWS clutch is activated and the lower leg attachment rotates in the flexion direction relative to the thigh attachment and cylindrical member, the lug surface in contact with the spider arm surface is pressed against the spider arm, compressing the urethane, and the inverting SSWS expands relative to the inner surface of the cylindrical member, preventing rotation of the cylindrical member relative to the inverting SSWS. Nevertheless, the lower leg attachment rotates by a small angle in the flexion direction relative to the thigh attachment and cylindrical member. The small angle relaxation is a controlled small amount of flexion allowed by the BSorNWS clutch mechanical joint at positions or time points 111 and 113 in the gait cycle shown in Figure 1A. The angular range of the small angle relaxation can be controlled by using multiple spiders with different compression ratios. There are various alternative implementation methods for the flexion prevention override mechanism, as will be described later. The flexion prevention override mechanism was not provided in the conventionally disclosed WSC mechanical joint, and therefore represents another improvement incorporated into the BSorNWS mechanical joint according to this disclosure compared to the conventionally disclosed WSC mechanical joint.

[0057] Figure 14 shows yet another improvement incorporated into the BSorNWS mechanical joint according to this disclosure. When the BSorNWS-clutch mechanical joint is used as a mechanical knee joint in a prosthesis, the threshold force generated by the load on the lower leg required to activate the BSorNWS needs to be varied depending on the rotational direction of the lower leg attachment and the thigh attachment. When a prosthesis user is standing on the prosthesis, as shown in section 1402, with the lower leg fully extended relative to the thigh, the weight is entirely on the prosthesis. In contrast, when the user is sitting and the lower leg attachment is at a 90° angle to the thigh attachment, as shown in section 1404, the majority of the user's weight is transferred to the chair or other object the user is sitting on, so only a small weight is on the prosthesis. When the user begins to stand up from a seated position, the BSorNWS clutch needs to be activated to prevent the prosthesis from buckling, but as mentioned above, when the user is in this position, only a small weight is transferred to the lower leg of the prosthesis. In contrast, as shown in cross-sectional figure 1402, the BSorNWS clutch also needs to be activated in a standing position, but since the prosthesis is subjected to the maximum load, any load smaller than the maximum load can be used as the threshold load for activating the BSorNWS clutch in a standing position. In practice, it is desirable that the threshold load for activating the BSorNWS clutch be relatively large at or near full extension so that the BSorNWS clutch is released at the appropriate position and time in the gait cycle. Also, it is desirable that the threshold load for activating the BSorNWS clutch be relatively small at 90 degrees of flexion so that the BSorNWS clutch is activated when the user begins to stand up from a seated position.

[0058] Figure 14 shows an embodiment of a mechanism for changing the load threshold for activation. This mechanism comprises an asymmetric cylinder 1406 having a cam-shaped projection 1408 rotatably fixed to the thigh attachment, a cam follower 1410, and a spring 1412. As shown in cross-section 1402, in a standing position with 0° flexion, the cam rotates the cam follower outward around the hinge 1414, pushing down the spring 1412. The spring then generates a force in the opposite direction to the force generated by the weighted lower leg, increasing the threshold load for activating the BSorNWS clutch. On the other hand, as shown in cross-section 1404, in a seated position with 90° flexion, the cam follower is in a more upright position and does not push down the spring. Since the spring is relatively uncompressed, the force it generates to counteract the force generated by the load on the lower leg is much smaller, or it generates no force at all. Therefore, the threshold load for activating the BSorNWS clutch is much lower.

[0059] In summary, the BSorNWS clutch mechanical joint according to the present disclosure comprises the following main components: (1) a housing, (2) a BSorNWS clutch enclosed within the housing, (3) a leg attachment that moves toward the housing when the BSorNWS clutch mechanical joint is loaded and moves toward the housing when the BSorNWS clutch mechanical joint is not loaded, (4) a thigh attachment that rotates to the full extension direction relative to the thigh attachment but does not rotate toward the flexion direction when the BSorNWS clutch is activated, and (5) a mechanical bypass that activates a bypassable coil spring clutch when the leg attachment moves toward the housing and disengages the BSorNWS clutch when the leg attachment moves toward the housing. Specific embodiments of the BSorNWS clutch mechanical joint according to the present disclosure further include the following: (6) A position-dependent load threshold adjustment device, and (7) a mechanical flexion prevention override that allows slight rotation of the lower leg attachment relative to the thigh attachment when a load is applied to the BSorNWS clutch mechanical joint. The five main components of the BSorNWS clutch mechanical joint according to this disclosure and the two additional components of the BSorNWS clutch mechanical joint according to this disclosure can each be implemented in a number of different alternative ways, some of which are described in the following subsections of this document. Various alternative embodiments of mechanical joints incorporating the BSoRNWS clutch according to this disclosure

[0060] Figure 15 shows a nested spring coil spring (NSWS) and a BS or NWS clutch containing the NSWS. The NSWS shown in Figure 15 includes (1) a small-diameter inner inverted single-spring coil spring (SSWS) 1502 with a coil wound in a first direction, (2) two-piece cylindrical members 1504 and 1506, and (3) a large-diameter outer SSWS 1508 wound in a second direction. The inner inverted SSWS 1502 is located within the two-piece cylindrical members 1504 and 1506. The two-piece cylindrical members containing the inner inverted SSWS are located within the outer SSWS 1508. Figure 15 shows a perspective view 1510 of the assembled NSWS. Finally, Figure 15 shows the assembled NSWS clutch 1514. The NSWS clutch is activated when the inner inverted SSWS expands outward and presses against the inner surface of the two-piece cylindrical members, causing the outer SSWS to clamp against the outer surface of the two-piece cylindrical members. When the assembled NSWS1510 is viewed along the symmetrical long axis from end 1516, the NSWS, including the assembled NSWS1510, acts when the proximal ends of the inner and outer SSWS, which are attached to the housing near the distal end 1518, rotate clockwise relative to the two-piece cylindrical member, and disengages when the inner and outer SSWS rotate counterclockwise. The BSorNWS clutch, including the NSWS, is smaller than the conventionally disclosed double-wound spring and WSC, as is the BSorNWS clutch, including the SSWS. Therefore, as described above, whether using SSWS or NSWS, the use of the BSorNWS clutch makes it easier to achieve hermetically sealed and enables the realization of a BSorNWS clutch mechanical joint that increases design flexibility for use as a mechanical knee joint in prosthetics. The BSorNWS clutch can be most effectively implemented by using (1) an SSWS that clamps onto a cylindrical friction surface to actuate the clutch, (2) a reversible SSWS that expands outward and presses against a cylindrical friction surface to actuate the clutch, or (3) an NSWS such as the NSWS1510 shown in Figure 15.

[0061] Figures 16A-C show an alternative anti-flexion override mechanism that allows the lower leg attachment to rotate slightly in the flexion direction relative to the thigh attachment when a load is applied to the BSorNWS clutch mechanical joint. Figure 16A shows a perspective view 1602 of the upper part of the housing (1118 in Figure 11C) incorporating the alternative anti-flexion override mechanism. A second perspective view 1604 shows the upper part of the housing with the cap 1606 removed. This mechanism includes a first slotted ring 1608 with slots and tabs corresponding to the slots and tabs of the cap 1606. Ring 1610 has a stopper mechanism such as stopper mechanism 1612, the outer portion of which fits into the slots of the first ring. Large two-prong lugs such as lug 1614 are fixed to the housing end of the inverted SSWS 1616. A urethane spider 1620 fills the gap between the lugs. The spider is rotatably secured to the housing via spider tabs located on the inner surface of 1606, which are inserted into spaces between the spider and lugs, such as space 1618. When the BSorNWS clutch is activated, the housing, rotatably secured to the lower leg attachment, rotates a little further counterclockwise as viewed from Figure 16A, until the leading surfaces of the lugs contact the rear end surfaces of the stopper mechanism, and then rotates a little further as the stopper mechanism compresses the urethane spider. The amount of flexion-prevention override by the flexion-prevention override mechanism can be changed by replacing ring 1610 with another ring having a stopper mechanism with wider or narrower projections. Figure 16B shows an exploded view of the flexion-prevention override mechanism described above with reference to Figure 16A. Figure 16C shows an exploded view from a different viewpoint than Figure 16B. Note that from this viewpoint, spider tabs 1622-1624 located on the inner surface of 1606 are visible.

[0062] Figure 17 shows an alternative embodiment of the lower leg attachment that moves relative to the housing depending on whether or not a load is applied to the lower leg attachment, as described above. In this alternative embodiment, which shows three perspective views 1702-1704 in Figure 17, the lower leg attachment 1706 is attached to the housing 1708 via a pair of thin, planar flexures 1710-1711. The lower leg attachment needs to move only a few millimeters relative to the housing, which is represented by a narrow gap 1712 in the embodiment shown in Figure 17. When a load is applied to the lower leg attachment, this gap closes, and when no load is applied to the lower leg attachment, this gap opens to more than 1 millimeter, and this small movement is transmitted to the BSorNWS clutch via a bypass linkage 1714. In the alternative embodiment, the bypass mechanism is actuated by moving the upper arm 1716 of the bypass linkage downward, which is converted into rotation of one end of the SSWC, inverting SSWC, or NSWC in the BSorNWS clutch.

[0063] Figures 18A–C show yet another different alternative embodiment of the lower leg attachment. Figure 18A shows three perspective views 1802–1804 of this embodiment. The lower leg attachment 1806 is attached to the top of the BSorNWS clutch mechanical joint 1808 via a pair of rotating, nearly horizontal arms 1810–1811. By slightly rotating these arms, the lower leg attachment 1806 moves perpendicular to the top of the BSorNWS clutch mechanical joint. The mechanism for changing the aforementioned operating load threshold can be seen in the cam-shaped configuration of the housing 1816 and the cam follower 1818. As shown in Figure 18B, the implementation shown in Figures 18A–C includes a flexion-prevention override mechanism including a cap 1820 and a recess 1822 (with an internal urethane compression mechanism). As shown in Figure 18C, the rotating, nearly horizontal pair of arms 1810-1811 lock together to prevent the lower leg attachment from moving more than slightly vertically relative to the upper part of the BSorNWS clutch mechanical joint when no load is applied to it.

[0064] Figures 19A-B show the alternative bypass mechanism described above with reference to Figure 17. Figure 19A shows two perspective views 1902 and 1904 of the alternative bypass mechanism, and Figure 1904 shows the internal components assembled with the cap portion 1906 of the housing removed. The upper arm 1908 of the bypass linkage moves vertically up and down depending on whether a load is applied to the lower leg mounting point or not. This vertical movement is converted into rotational motion of the SSWC, inverted SSWC, or NSWC within the BSorNWS clutch by the rotational motion of the wing-shaped bracket 1908. Figure 19B shows an exploded view of the alternative bypass mechanism. The upper arm of the bypass linkage 1908 rotates the hinge 1910, and the rotation of the hinge as the upper arm moves downward pushes the round shaft 1912 inward into the BSorNWS. This causes the vertical axis of the elliptical cross section 1914 to be pressed against the curved surfaces 1916 and 1917 of the winged bracket 1908, which in turn rotates the end of the inverted SSWC 1920 shown in Figure 19B. The advantage of this alternative bypass mechanism is that it operates correctly regardless of the angle adjustment between the winged bracket 1908 and the end of the inverted SSWC 1920.

[0065] In summary, the BSorNWS clutch mechanical joint according to this disclosure comprises the following main components: (1) housing, (2) BSorNWS clutch, (3) lower leg attachment, (4) thigh attachment, and (5) mechanical bypass. Certain embodiments of the BSorNWS clutch mechanical joint according to this disclosure further include (6) a position-dependent load threshold adjustment device and (7) a mechanical flexion prevention override. Each of the five main components and two additional components can be implemented in various ways. The housing can have various shapes and dimensions and can be made from metal or metal alloys, or composite materials such as fiberglass or various types of polymer materials. As described above, mechanical joints with BSorNWS clutch mechanisms, which implement SSWC, inverted SSWC, and NSWS respectively, have a smaller volume than conventionally disclosed mechanical joints with WSC mechanisms, and the use of BSorNWS clutch mechanical joints makes it possible to make the housing smaller and easier to hermetically seal in applications to prostheses. Furthermore, this miniaturization reduces the need for complex and precise adjustments and alignments associated with long, double-wound spring clutches.

[0066] As described above, the BSorNWS clutch can be implemented using an SSWC, inverted SSWC, or NSWS. Unlike the previously disclosed WSC, the BSorNWS clutch is fully housed within a housing and supported by the housing, thus simplifying the manufacture of the BSorNWS clutch and significantly improving reliability and robustness. As described above, the BSorNWS clutch reduces unnecessary delays in clutch operation and release, and unnecessary frictional forces that do not contribute to clutch operation and release, by using one or more coil springs with variable coil width and coil pitch. Various implementations of the BSorNWS clutch according to this disclosure may feature SSWCs, inverted SSWCs, and NSWS with different numbers of coils, different coil widths and pitches, different materials used in the manufacture of the SSWC, inverted SSWC, and NSWS, different sizes and shapes, different types of mountings to the housing and mechanical bypass, and may otherwise differ from one another.

[0067] The lower leg and thigh attachments may have different mechanical structures for attachment to the lower leg and thigh of the prosthesis. The lower leg attachment may be slidably mounted within the lower leg attachment joint, as in the embodiment described above with reference to Figures 11A-D, but may be implemented alternatively, as described above with reference to Figures 17 and 18A-C. Depending on whether the lower leg attachment is weighted or not, many other alternative implementations are possible to allow controlled movement of the lower leg attachment relative to the housing. Various different implementations of mechanical bypasses have been described above with reference to Figures 4A-7E, 11B, 12, and 19A-B, but many additional implementations are possible. Similarly, various implementations of position-dependent weight threshold adjustment devices and flexion-prevention override mechanisms are possible, including those described above with reference to Figures 13, 14, and 16A-C.

[0068] Another alternative mechanical bypass can be implemented by clamping and fixing the inverting SSWS to the arbor. The arbor rotates independently of the cylindrical member into which the inverting SSWS expands to actuate the clutch, via the bypass mechanism. Essentially, the arbor and cylindrical member form a nested friction surface between which the inverting SSWS is positioned. To disengage the clutch, which includes the nested friction surface and the inverting SSWS, the arbor is rotated in the direction that clamps and fixes the inverting SSWS to the arbor, thereby releasing the inverting SSWS from contact with the inner friction surface of the cylindrical member. Similarly, to actuate the clutch, the arbor needs to be rotated slightly in the opposite direction to release the coil or the inverting SSWS. For this alternative mechanical bypass to work, the outer surface and inner surface of the coil of the inverting SSWS must not be pressed simultaneously against the two nested friction surfaces of the cylindrical member and the arbor while the clutch is actuated and disengaged, because this would prevent the clutch from transitioning from the actuated state to the disengaged state and from the disengaged state to the actuated state. To prevent the outer surface and inner surface of the coil of the inverted SSWS from being pressed against two nested friction surfaces simultaneously, both during loading and unloading, various methods can be used, such as varying the diameter of the inverted SSWS along its length, varying the diameter of the cylindrical member, or extending the SSWS beyond the end of the cylindrical member so that only the extended portion interacts with the axis.

[0069] In a sense, the BSorNWS clutch mechanical joint according to this disclosure is a modular system defined by the functions of the main component and the two additional compartments and their interactions. Different implementations of the BSorNWS clutch mechanical joint according to this disclosure may have different implementations of components or modules, but all implementations of the BSorNWS clutch according to this disclosure are commonly defined by the functions of the modules or components and their interactions.

[0070] While the present invention has been described based on specific embodiments, it is not limited to these embodiments. Modifications that do not depart from the spirit of the invention will be apparent to those skilled in the art. This specification has described and illustrated numerous alternative implementations of various components and modules of the BSorNWS clutch mechanical joint according to the present disclosure. The BSorNWS clutch mechanical joint according to the present disclosure, and other types of mechanical joints employing the BSorNWS clutch, can be used in a wide range of applications, including not only prosthetics but also robots, complex mechanical and electromechanical systems, and many other applications.

Claims

1. It is a mechanical joint, Housing and A clutch is included within the housing and is one of the following: a single-spring coil spring clutch, a reverse single-spring coil spring clutch, and a nested spring coil spring clutch. A lower leg mounting portion that moves toward the housing when a load is applied to the mechanical joint, and moves away from the housing when no load is applied to the mechanical joint, A thigh attachment portion, which rotates until the lower leg attachment portion is fully extended in the extension direction relative to the thigh attachment portion, but does not rotate in the flexion direction when the clutch is engaged, A mechanical bypass engages the clutch when the lower leg mounting section moves toward the housing and disengages the clutch when the lower leg mounting section moves toward the housing. A mechanical joint equipped with [a specific feature].

2. The housing includes the clutch and mechanical bypass, and partially includes the lower leg mounting section. The mechanical joint according to claim 1.

3. The housing hermetically seals the clutch and mechanical bypass. The mechanical joint according to claim 1.

4. A single-spring coil clutch includes a spring with a coil whose width and pitch vary, which tightens the friction surface when the clutch is engaged and releases it when the clutch is disengaged. The mechanical joint according to claim 1.

5. A reversible single-spring coil clutch includes a spring with a coil whose width and pitch vary, which expands to the friction surface when the clutch is engaged and is released from the friction surface when the clutch is disengaged. The mechanical joint according to claim 1.

6. A nested spring-type coil spring clutch is, A cylindrical member and A first spring having a coil with varying width and pitch that expands to the inner friction surface of the cylindrical member when the clutch is engaged, but is released from the inner friction surface of the cylindrical member when the clutch is disengaged, A second spring having a coil with varying width and pitch tightens the outer friction surface of the cylindrical member when the clutch is engaged, but releases it from the outer friction surface of the cylindrical member when the clutch is disengaged, A mechanical joint according to claim 1, comprising:

7. The lower leg attachment portion is partially mounted within the housing in a slidable manner. The mechanical joint according to claim 1.

8. The lower leg attachment portion is attached to the housing by one or more flexed portions. The mechanical joint according to claim 1.

9. The lower leg attachment section is attached to the housing by one or more rotating arms. The mechanical joint according to claim 1.

10. The thigh attachment is attached to a cylindrical member of the clutch that restricts the rotational movement of the thigh attachment relative to the lower leg attachment when the clutch is engaged. The mechanical joint according to claim 1.

11. The mechanical bypass converts the translational motion of the lower leg mounting portion relative to the housing into rotational motion transmitted to one end of a single-spring coil spring or a reversing single-spring coil spring within the clutch. The mechanical joint according to claim 1.

12. The mechanical bypass converts the translational motion of the lower leg mounting portion relative to the housing into rotational motion transmitted to adjacent ends of two coil springs in a nested coil spring within the clutch. The mechanical joint according to claim 1.

13. The mechanical bypass converts the translational motion of the lower leg mounting portion relative to the housing into rotational motion transmitted to one end of either a spring or a nested coil spring within the clutch. The mechanical joint according to claim 1.

14. The mechanical joint according to claim 1, further comprising a flexion-prevention override that allows rotation of the lower leg attachment relative to the thigh attachment when the clutch is engaged.

15. The anti-flex override allows rotation in the flex direction between 0° and 12°. The mechanical joint according to claim 14.

16. The amount of rotation in the bending direction permitted by the anti-bending override depends on the compressibility of the polymer material component of the anti-bending override that is compressed to allow rotation in the bending direction. The mechanical joint according to claim 15.

17. The mechanical joint according to claim 1, further comprising a position-dependent load threshold adjustment device for changing the load threshold for activating a clutch.

18. The position-dependent load threshold adjustment device is A cam that rotates together with the thigh attachment part, A spring that is compressed when the lower leg attachment moves toward the housing, and depressurized when the lower leg attachment moves toward the housing, A cam follower in which the lower leg attachment portion and the thigh attachment portion are parallel or nearly parallel, and the spring is compressed when the lower leg attachment portion is fully extended or nearly fully extended, The mechanical joint according to claim 17, comprising:

19. A mechanical joint according to claim 1, which is incorporated into a prosthetic leg.

20. The lower leg attachment mechanism is attached to the corresponding attachment mechanism on the lower leg of the prosthetic leg, and the thigh attachment mechanism is attached to the corresponding attachment mechanism on the thigh of the prosthetic leg. The mechanical joint according to claim 19.

Images