Patent Description:
Motion assistance apparatuses enabling the elderly and/or patients having joint problems to walk with less effort, and motion assistance apparatuses increasing muscular strength of human bodies for military purposes have been developed.

<CIT> is considered the closest prior art, relative to which at least the features of the characterizing portion of claim <NUM> are novel. <CIT> and <CIT> are acknowledged as further prior art.

Some example embodiments relate to a frame assembly.

In some example embodiments, the frame assembly includes a first longitudinal member; a second longitudinal member spaced apart from the first longitudinal member; and a plurality of distance maintaining members connecting the first longitudinal member and the second longitudinal member, the plurality of distance maintaining members configured to maintain a distance between the first longitudinal member and the second longitudinal member.

In some example embodiments, the first longitudinal member and the second longitudinal member each have ends with an intermediate portion there between, and the plurality of distance maintaining members connect the first longitudinal member and the second longitudinal member such that the intermediate portion of the second longitudinal member moves relative to the intermediate portion of the first longitudinal member.

In some example embodiments the second longitudinal member is parallel with the first longitudinal member.

In some example embodiments the frame assembly has ends with an intermediate portion there between, and the intermediate portion of the frame assembly is configured to flex in response to a force applied in a lateral direction thereto.

In some example embodiments the first longitudinal member and the second longitudinal member each include a flexible material.

In some example embodiments, a length of each of the plurality of distance maintaining members is less than a length of each of the first longitudinal member and the second longitudinal member.

In some example embodiments, adjacent ones of the plurality of distance maintaining members are separated by a distance, the distance being less than a length of each of the plurality of distance maintaining members.

In some example embodiments, the plurality of distance maintaining members each include a first material, the first longitudinal member includes a second material and the second longitudinal member includes a third material, the first material being stiffer than the second material and the third material.

The plurality of distance maintaining members has a first end portion and a second end portion with an intermediate portion there between, and the first end portion and the second end portion of the at least one of the plurality of distance maintaining members may be fixed to the first longitudinal member and the second longitudinal member, respectively.

In some example embodiments, both of the first end portion and the second end portion of the at least one of the plurality of distance maintaining members are more flexible than the intermediate portion of the at least one of the plurality of distance maintaining members.

In some example embodiments, at least one of the first end portion and the second end portion of the at least one of the plurality of distance maintaining members is rotatably fixed to one of the first longitudinal direction and the second longitudinal member.

In some example embodiments, at least one of the plurality of distance maintaining members includes a first slider and a second slider, a first one of the first slider and the second slider being configured to slide relative to a second one of the first slider and the second slider.

In some example embodiments, the at least one of the plurality of distance maintaining members further includes a separation preventing member configured to inhibit separation between the first slider and the second slider.

In some example embodiments, at least one of the plurality of distance maintaining members is slidably connected to one of the first longitudinal member and the second longitudinal member.

In some example embodiments, the first longitudinal member and the second longitudinal member each have a first end and a second end with an intermediate portion there between, and the frame assembly further includes a first object and a second object, the first object connected to the first end of the first longitudinal member and the first end of the second longitudinal member, and the second object connected to the second end of the first longitudinal member and the second end of the second longitudinal member.

In some example embodiments, the second end of the second longitudinal member is connected to the second object such that the second end of the second longitudinal member moves in a direction that intersects a longitudinal direction of the second object.

The plurality of distance maintaining members has a first end portion and a second end portion with an intermediate portion there between, and the first end portion of at least one of the plurality of distance maintaining members may be fixed to the first longitudinal member, and the second end portion of the at least one of the plurality of distance maintaining members may be slidably connected to the second longitudinal member.

In some example embodiments, the first object is configured to support a first portion of a user, and the second object is configured to support a second portion of the user, the first portion and the second portion of the user being on opposite sides of a joint of the user.

In some example embodiments, the frame assembly is configured to apply a torque to the second object to rotate the second object relative to the first object, if a tensile force is applied to the second longitudinal member.

In some example embodiments, the first longitudinal member is on a first side of the first portion and the second portion of the user, and the second longitudinal member is on the first side of the first portion and the second portion of the user, and the frame assembly further includes: a third longitudinal member on a second side of the first portion and the second portion of the user such that the third longitudinal member is opposite the first longitudinal member, the third longitudinal member configured to connect the first object and the second object; a fourth longitudinal member on the second side of the first portion and the second portion of the user such that the fourth longitudinal member is opposite the second longitudinal member, the fourth longitudinal member configured to connect the first object and the second object; and a plurality of second distance maintaining members fixed to the third longitudinal member, the plurality of second distance maintaining members slidably connected to the fourth longitudinal member.

In some example embodiments, the first longitudinal member is an elastic body.

In some example embodiments, a height of at least one of the plurality of distance maintaining members decreases from the first longitudinal member toward the second longitudinal member.

Some example embodiments relate to a motion assistance apparatus.

In some example embodiments, the motion assistance apparatus includes a first object configured to attach to a first portion of a user; a second object configured to attach to a second portion of the user; and a frame assembly including, a first longitudinal member configured to connect the first object and the second object, a second longitudinal member spaced apart from the first longitudinal member, and a plurality of distance maintaining members connecting the first longitudinal member and the second longitudinal member.

In some example embodiments, the motion assistance apparatus further includes a rotary body connected to one of the first longitudinal member and the second longitudinal member, wherein the frame assembly is configured to perform one of a flexion motion and an extension motion based on a direction of rotation of the rotary body.

In some example embodiments, one of the first longitudinal member and the second longitudinal member is an elastic body, and an initial state of the frame assembly is a flexion state.

Hereinafter, some example embodiments will be described in detail with reference to the accompanying drawings. Regarding the reference numerals assigned to the elements in the drawings, it should be noted that the same elements will be designated by the same reference numerals, wherever possible, even though they are shown in different drawings. Also, in the description of embodiments, detailed description of well-known related structures or functions will be omitted when it is deemed that such description will cause ambiguous interpretation of the present disclosure.

It should be understood, however, that there is no intent to limit this disclosure to the particular example embodiments disclosed. On the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of the example embodiments. Like numbers refer to like elements throughout the description of the figures.

In addition, terms such as first, second, A, B, (a), (b), and the like may be used herein to describe components. It should be noted that if it is described in the specification that one component is "connected", "coupled", or "joined" to another component, a third component may be "connected", "coupled", and "joined" between the first and second components, although the first component may be directly connected, coupled or joined to the second component.

In the drawings, the thicknesses of layers and regions are exaggerated for clarity.

<FIG> illustrates a frame assembly according to at least one example embodiment.

Referring to <FIG>, a frame assembly <NUM> may include a first longitudinal member <NUM>, a second longitudinal member <NUM>, and a plurality of distance maintaining members <NUM>. The distance maintaining members <NUM> may be connected between the first longitudinal member <NUM> and the second longitudinal member <NUM>. The distance maintaining members <NUM> may maintain a desired (or, alternatively, a predetermined) distance between the first longitudinal member <NUM> and the second longitudinal member <NUM>. The distance maintaining members <NUM> may enable the second longitudinal member <NUM> to maintain substantially the same distance from the first longitudinal member <NUM> although the frame assembly <NUM> is deformed by an external force applied to the frame assembly <NUM>. An intermediate area of one of the first longitudinal member <NUM> and the second longitudinal member <NUM> may move relative to an intermediate area of the other of the first longitudinal member <NUM> and the second longitudinal member <NUM>. The distance maintaining members <NUM> may enable the frame assembly <NUM> to maintain a desired (or, alternatively, a predetermined) shape based on bending levels of the two longitudinal members <NUM> and <NUM>. The distance maintaining members <NUM> may prevent buckling of the first longitudinal member <NUM> and the second longitudinal member <NUM>.

The first longitudinal member <NUM> and the second longitudinal member <NUM> may each connect a first object <NUM> and a second object <NUM>. The second longitudinal member <NUM> may be spaced apart from the first longitudinal member <NUM>, for example, parallel with the first longitudinal member <NUM>. The first longitudinal member <NUM> and the second longitudinal member <NUM> may each include a flexible material. One or both of the first longitudinal member <NUM> and the second longitudinal member <NUM> may each include a material that is flexible while having a stiffness sufficient to prevent buckling by a self-weight, for example, a material such as synthetic resin. A flexural stiffness of the first longitudinal member <NUM> and/or the second longitudinal member <NUM> may be <NUM>% less than a longitude stiffness of the first longitudinal member <NUM> and/or the second longitudinal member <NUM>. The first longitudinal member <NUM> and/or the second longitudinal member <NUM> may be an elastic body that restores the original shape when an external force is not applied thereto.

Both end portions of the first longitudinal member <NUM> may be fixed to the first object <NUM> and the second object <NUM>, respectively. Both end portions of the second longitudinal member <NUM> may also be fixed to the first object <NUM> and the second object <NUM>, respectively. For example, the first longitudinal member <NUM> and the second longitudinal member <NUM> may be provided in a form of plates having sides facing each other.

The distance maintaining members <NUM> may rotate, bend, or slide relative to the first longitudinal member <NUM> and/or the second longitudinal member <NUM>. In the above structure, the second longitudinal member <NUM> may maintain substantially the same distance from the first longitudinal member <NUM> while the intermediate area of the first longitudinal member <NUM> and the intermediate area of the second longitudinal member <NUM> may move relative to sides facing each other. Thus, the frame assembly <NUM> may have a flexibility in a direction perpendicular to an intermediate area thereof.

Lengths of the distance maintaining members <NUM> may be less than a length of the first longitudinal member <NUM> and a length of the second longitudinal member <NUM>. To improve a flexural rigidity of the frame assembly <NUM>, a distance d between two adjacent distance maintaining members <NUM> in an initial state in which an external force is not applied may be less than the lengths of the distance maintaining members <NUM>. The plurality of distance maintaining members <NUM> may each include a material that is stiffer than a material included in the first longitudinal member <NUM> and a material included in the second longitudinal member <NUM>.

<FIG> illustrates an operation of a frame assembly when a force is applied to an intermediate area of the frame assembly in a lateral direction according to at least one example embodiment. <FIG> illustrates a case in which the first object <NUM> and the second object <NUM> are fixed not to move relative to each other.

Referring to <FIG>, when a force F is applied to an intermediate area of the frame assembly <NUM> in a lateral direction, the first longitudinal member <NUM> and the second longitudinal member <NUM> may bend by the force F. In this example, the first longitudinal member <NUM> and the second longitudinal member <NUM> may move relative to each other while maintaining a distance there between through the distance maintaining members <NUM>. For example, in a case in which both end portions of the first longitudinal member <NUM> are fixed to the first object <NUM> and the second object <NUM>, respectively, and both ends portions of the second longitudinal member <NUM> are fixed to the first object <NUM> and the second object <NUM>, respectively, a relative angle between the first object <NUM> and the second object <NUM> may be maintained the same. Thus, the first longitudinal member <NUM> and the second longitudinal member <NUM> may bend in the same shapes.

<FIG> illustrates an operation of a frame assembly when a torque is applied to an end portion of the frame assembly according to at least one example embodiment, and <FIG> illustrates an operation of a frame assembly not including distance maintaining members when a torque is applied to an end portion of the frame assembly according to at least one example embodiment. <FIG> and <FIG> illustrate a motion of the frame assembly <NUM> and a motion of a frame assembly <NUM>', respectively, when a torque is applied to an end portion of the first object <NUM> in a case in which the first object <NUM> and the second object <NUM> move relative to each other, for example, in a case in which the first object <NUM> is a free end and the second object <NUM> is a fixed end. Hereinafter, a comparison between the examples of <FIG> and <FIG> will be described.

Referring to <FIG>, when a torque T is applied to the first object <NUM> of the frame assembly <NUM>' not including distance maintaining members, the first longitudinal member <NUM> may bend at a first curvature R1, and the second longitudinal member <NUM> may bend at a second curvature R2 that is greater than the first curvature R1, whereby the entire frame assembly <NUM>' may bend. Thus, the frame assembly <NUM>' of <FIG> may not perfectly transfer the torque T applied to the first object <NUM> to the second object <NUM>. That is, only a portion of the torque T may be transferred.

Conversely, in a case of the frame assembly <NUM> including the distance maintaining members <NUM> as shown in <FIG>, a distance between the first longitudinal member <NUM> and the second longitudinal member <NUM> may be maintained. The two longitudinal members <NUM> and <NUM> may not bend at different curvatures. A torque of the same size as the torque T applied to the first object <NUM> may be applied to the second object <NUM> in an opposite direction. Thus, the frame assembly <NUM> of <FIG> may perfectly transfer the torque T applied to the first object <NUM> to the second object <NUM>. In the above structure, the frame assembly <NUM> may transfer a torque in both directions.

<FIG> illustrate examples of frame assemblies according to at least one example embodiment.

Referring to <FIG>, a frame assembly <NUM> may include a first object <NUM>, a second object <NUM>, a first longitudinal member <NUM>, a second longitudinal member <NUM>, and distance maintaining members <NUM>.

Both end portions of the first longitudinal member <NUM> may be fixed to the first object <NUM> and the second object <NUM>, respectively. For example, both the end portions of the first longitudinal member <NUM> may be rotatably hinge-connected to the first object <NUM> and the second object <NUM>. Similar to both the end portions of the first longitudinal member <NUM>, both end portions of the second longitudinal member <NUM> may also be fixed to the first object <NUM> and the second object <NUM>, respectively.

One or both end portions of each distance maintaining member <NUM> may be rotatably fixed to the first longitudinal member <NUM> and/or the second longitudinal member <NUM>. In the above structure, the second longitudinal member <NUM> may maintain substantially the same distance from the first longitudinal member <NUM> while an intermediate area of the first longitudinal member <NUM> and an intermediate area of the second longitudinal member <NUM> may partially slide relative to sides facing each other. <FIG> illustrates both the end portions of each distance maintaining member <NUM> being rotatably hinge-connected to the first longitudinal member <NUM> and the second longitudinal member <NUM>. The distance maintaining members <NUM> may include a rigid structure and material.

A portion of the distance maintaining members <NUM> has a flexible structure or material, and thus may bend with respect to the first longitudinal member <NUM> and the second longitudinal member <NUM>. In the above structure, the second longitudinal member <NUM> may maintain substantially the same distance from the first longitudinal member <NUM> while an intermediate area of the first longitudinal member <NUM> and an intermediate area of the second longitudinal member <NUM> may partially slide relative to sides facing each other. For example, both end portions of each distance maintaining member <NUM> may have cross sections that are <NUM>/<NUM> to <NUM>/<NUM> of a cross section of an intermediate area thereof. For example, the intermediate area of each distance maintaining member <NUM> may have a rigid material or structure.

Unlike <FIG>, a thickness of each distance maintaining member <NUM> may be greater than a thickness of the first longitudinal member <NUM> and a thickness of the second longitudinal member <NUM>. Each distance maintaining member <NUM> may have a thickness sufficient to prevent buckling of the first longitudinal member <NUM> and the second longitudinal member <NUM>, for example, a thickness that is <NUM> to <NUM> times greater than the thickness of the first longitudinal member <NUM> and the thickness the second longitudinal member <NUM>.

<FIG> illustrates a frame assembly according to at least one example embodiment, and <FIG> illustrates an operation of the frame assembly when a force is applied to an intermediate area of the frame assembly in a lateral direction according to at least one example embodiment.

Referring to <FIG> and <FIG>, a frame assembly <NUM> may include a first object <NUM>, a second object <NUM>, a first longitudinal member <NUM>, a second longitudinal member <NUM>, and distance maintaining members <NUM>.

The distance maintaining members <NUM> may each include a first slider <NUM> and a second slider <NUM> configured to slide relative to each other. In the above structure, the second longitudinal member <NUM> may maintain substantially the same distance from the first longitudinal member <NUM> while an intermediate area of the first longitudinal member <NUM> and an intermediate area of the second longitudinal member <NUM> may partially slide relative to sides facing each other.

The frame assembly <NUM> may have a flexibility in a direction perpendicular to an intermediate area thereof. When a force F is applied to the intermediate area of the frame assembly <NUM> as shown in <FIG>, the first longitudinal member <NUM> and the second longitudinal member <NUM> may bend by the force F. In this example, the first longitudinal member <NUM> and the second longitudinal member <NUM> may partially slide relative to each other while maintaining the distance therebetween through the distance maintaining members <NUM>. Thus, the first longitudinal member <NUM> and the second longitudinal member <NUM> may bend in the same shapes.

<FIG> are examples of distance maintaining members according to at least one example embodiment. <FIG> are top views of a portion A of <FIG>, viewed in a negative direction of a y axis.

Referring to <FIG>, a distance maintaining member <NUM> may include a first slider <NUM>, and a second slider <NUM> configured to slide relative to the first slider <NUM>.

The first slider <NUM> may include a first slider body 551a connected to the first longitudinal member <NUM> and configured to extend toward the second longitudinal member <NUM>, and a first fitting portion 551b formed on the first slider body 551a. The first slider body 551a and/or the first fitting portion 551b may include a rigid structure and material.

The second slider <NUM> may include a second slider body 552a connected to the second longitudinal member <NUM> and configured to extend toward the first longitudinal member <NUM>, and a second fitting portion 552b formed on the second slider body 552a and configured to fit in the first fitting portion 551b. For example, the second slider body 552a and/or the second fitting portion 552b may include a rigid structure and material.

The first slider body 551a and the second slider body 552a may prevent buckling of the first longitudinal member <NUM> and the second longitudinal member <NUM> in a direction in which a distance there between decreases.

One of the first fitting portion 551b and the second fitting portion 552b may protrude, and the other of the first fitting portion 551b and the second fitting portion 552b may be recessed. The first fitting portion 551b and the second fitting portion 552b may engage with each other, whereby the first slider <NUM> and the second slider <NUM> may slide relative to each other without being separated from each other. The first fitting portion 551b may include a portion of which a width increases as a distance from the first slider body 551a increases. For example, the first fitting portion 551b may be provided in a dovetail shape in which a cross section thereof increases toward a protrude direction. The second fitting portion 552b may include a shape in which a cross section of a recess increases toward a recess direction.

Referring to <FIG>, a distance maintaining member <NUM> may include a first slider <NUM> that includes a first slider body 651a and a first fitting portion 651b, and a second slider <NUM> that includes a second slider body 652a and a second fitting portion 652b.

The first fitting portion 651b may include a portion of which a width increases as a distance from the first slider body 651a increases. For example, the first fitting portion 651b may have a circular cross section, and the second fitting portion 652b may have a cross section corresponding to a recess with two edges bending inward.

Referring to <FIG>, a distance maintaining member <NUM> may include a first slider <NUM> that includes a first slider body 751a and a first fitting portion 751b, a second slider <NUM> that includes a second slider body 752a and a second fitting portion 752b, and a separation preventing member <NUM>.

The separation preventing member <NUM> may prevent a separation between the first slider <NUM> and the second slider <NUM>. One side of the separation preventing member <NUM> may be coupled to the first fitting portion 751b and slidably move relative to the first fitting portion 751b. For example, the one side of the separation preventing member <NUM> may be provided in a reversed trapezoidal shape including a portion of which a width increases toward the first slider <NUM>. Similarly, another side of the separation preventing member <NUM> may be coupled to the second fitting portion 752b. That is, the separation preventing member <NUM> may be provided in a shape of combination of two reversed trapezoids including portions of which widths increase toward the two sliders <NUM> and <NUM>, respectively.

One or both end portions of a distance maintaining member <NUM> may be slidably connected to the first longitudinal member <NUM> and/or the second longitudinal member <NUM>. In the above structure, the second longitudinal member <NUM> may maintain substantially the same distance from the first longitudinal member <NUM> while an intermediate area of the first longitudinal member <NUM> and an intermediate area of the second longitudinal member <NUM> may slide relative to sides facing each other.

<FIG> illustrates a state in which one end portion of each distance maintaining member <NUM> is fixed to the first longitudinal member <NUM> and another end portion of each distance maintaining member <NUM> is slidably coupled to the second longitudinal member <NUM>. The distance maintaining member <NUM> may include a slider <NUM> configured to slide relative to the second longitudinal member <NUM>. The distance maintaining member <NUM> may include a rigid structure and material.

As shown in <FIG>, the frame assembly <NUM> may be flexible with respect to a force applied to an intermediate area thereof. Thus, when a force F is applied to the intermediate area of the frame assembly <NUM> in a lateral direction, the first longitudinal member <NUM> and the second longitudinal member <NUM> may bend by the force F. In this example, the first longitudinal member <NUM> and the second longitudinal member <NUM> may partially slide relative to each other while maintaining a distance there between through the distance maintaining members <NUM>. Thus, the first longitudinal member <NUM> and the second longitudinal member <NUM> may bend in the same shapes.

A longitudinal member including a flexible material may have a variation with respect to an applied force, the variation increasing as a distance from a fixed end increases according to the principle of the lever. A loss of torque corresponding to the variation may occur, and thus the longitudinal member including the flexible material may not perfectly transfer a torque from one end portion to another end portion. Conversely, a longitudinal member including a rigid material may perfectly transfer a torque from one end portion to another end portion. However, a flexibility of the longitudinal member including the stiff material may decrease at an intermediate portion. The frame assembly according to at least one example embodiment may have a flexible intermediate portion and also perfectly transfer a torque, thereby reducing friction with an object adjacent to the frame assembly and minimizing a loss of torque during a power transfer process.

<FIG> illustrates an initial state of a frame assembly according to at least one example embodiment, <FIG> illustrates an operation of the frame assembly when one of longitudinal members of the frame assembly is pulled according to at least one example embodiment, and <FIG> illustrates an operation of the frame assembly when one of the longitudinal members of the frame assembly is pushed according to at least one example embodiment.

Referring to <FIG>, a frame assembly <NUM> may include a first object <NUM>, a second object <NUM>, a first longitudinal member <NUM>, a second longitudinal member <NUM>, and distance maintaining members <NUM>. For example, the first longitudinal member <NUM> may include an elastic material that restores the original shape when an external force is not applied thereto.

Both ends of the first longitudinal member <NUM> may be fixed to the first object <NUM> and the second object <NUM>, respectively. Unlike both the ends of the first longitudinal member <NUM>, one end of the second longitudinal member <NUM> may be fixed to the second object <NUM>, and another end of the second longitudinal member <NUM> may be connected to the first object <NUM> to move relative to the first object <NUM>. The second longitudinal member <NUM> may be connected to the first object <NUM> to move in a direction that intersects a longitudinal direction of the first object <NUM>, for example, in a direction perpendicular thereto. Thus, the first object <NUM> may be slidably connected to the second longitudinal member <NUM>. The first object <NUM> may include a first slider <NUM> configured to slide relative to the second longitudinal member <NUM>. For example, the second longitudinal member <NUM> may penetrate through the first object <NUM>. In this example, a portion of the first object <NUM> through which the second longitudinal member <NUM> penetrates may correspond to the first slider <NUM>.

One or both end portions of a distance maintaining member <NUM> may be slidably connected to the first longitudinal member <NUM> and/or the second longitudinal member <NUM>. In the above structure, the second longitudinal member <NUM> may maintain substantially the same distance from the first longitudinal member <NUM> while an intermediate area of the first longitudinal member <NUM> and an intermediate area of the second longitudinal member <NUM> may partially slide relative to sides facing each other. <FIG> illustrates a state in which one end portion of each distance maintaining member <NUM> is fixed to the first longitudinal member <NUM> and another end portion of each distance maintaining member <NUM> is slidably coupled to the second longitudinal member <NUM>. The distance maintaining member <NUM> may include a second slider <NUM> configured to slide relative to the second longitudinal member <NUM>. The distance maintaining member <NUM> may include a rigid structure and material.

<FIG> and <FIG> illustrate an operation of the frame assembly <NUM> in response to a force applied to the second longitudinal member <NUM> in a case in which the first object <NUM> and the second object <NUM> move relative to each other. For example, the first object <NUM> may be attached to a thigh of a user and the second object <NUM> may be attached to a shin of the user such that the first object <NUM> and the second object <NUM> may move relative to each other.

Referring to <FIG>, when a force F to pull the second longitudinal member <NUM> is applied as shown in <FIG>, the first longitudinal member <NUM> and the second longitudinal member <NUM> may bend in a direction toward the second longitudinal member <NUM> from on a center of the frame assembly <NUM>. When the tensile force F is applied to the second longitudinal member <NUM>, a torque may be applied to the second object <NUM> in a clockwise direction in <FIG>, and a portion of the second object <NUM> connected to the second longitudinal member <NUM> may move toward the first object <NUM>. Meanwhile, the frame assembly <NUM> may have a flexibility in a direction perpendicular to an intermediate area thereof, and the first longitudinal member <NUM> and the second longitudinal member <NUM> may partially slide relative to each other while maintaining a distance there between through the distance maintaining members <NUM>. Thus, when the tensile force is applied to the second longitudinal member <NUM>, the first longitudinal member <NUM> and the second longitudinal member <NUM> may be deformed in similar shapes as shown in <FIG>. Hence, by the tensile force applied to the second longitudinal member <NUM>, the entire frame assembly <NUM> may bend in one direction.

Referring to <FIG>, the second longitudinal member <NUM> may include a material and structure that is rigid sufficient to prevent buckling with respect to a compressive force applied in a longitudinal direction. In this example, when a force F to push the second longitudinal member <NUM> is applied as shown in <FIG>, the first longitudinal member <NUM> and the second longitudinal member <NUM> may bend in a direction toward the first longitudinal member <NUM> from the center of the frame assembly <NUM>. When the compressive force F is applied to the second longitudinal member <NUM>, a torque may be applied to the second object <NUM> in a counterclockwise direction in <FIG>, and a portion of the second object <NUM> connected to the second longitudinal member <NUM> may move away from the first object <NUM>. The frame assembly <NUM> may have a flexibility in a direction perpendicular to the intermediate area thereof, and the first longitudinal member <NUM> and the second longitudinal member <NUM> may partially slide relative to each other while maintaining the distance there between through the distance maintaining members <NUM>. Thus, when the compressive force is applied to the second longitudinal member <NUM>, the first longitudinal member <NUM> and the second longitudinal member <NUM> may be deformed in similar shapes as shown in <FIG>. Hence, by the compressive force applied to the second longitudinal member <NUM>, the entire frame assembly <NUM> may bend in a direction opposite to the direction of <FIG>.

In the above structure, an angle between the first object <NUM> and the second object <NUM> may be adjusted. Thus, the frame assembly <NUM> may be used as various types of joint devices. Since the first object <NUM> and the second object <NUM> each have a variable center of rotation, the frame assembly <NUM> may imitate a joint motion of a person or animal having a center of rotation that continuously changes during a rotation motion. Further, since the frame assembly <NUM> may have a flexibility in a direction perpendicular to the intermediate area thereof, the frame assembly <NUM> may function as a joint while being deformed flexibly by an external force, thereby reducing an unnecessary load to be applied to a user who is wearing the frame assembly <NUM>.

The second longitudinal member <NUM> may include using a material and structure that is flexible sufficient to allow buckling with respect to a compressive force applied in a longitudinal direction, for example, a wire. In this example, although the compressive force is applied to the second longitudinal member <NUM>, a torque to rotate the second object <NUM> may not be applied. In this example, the frame assembly <NUM> may be deformed only in one direction based on the direction in which the force is applied to the second longitudinal member <NUM>. In detail, when a tensile force is applied to the second longitudinal member <NUM>, the frame assembly <NUM> may operate as shown in <FIG>. When the tensile force is released, the frame assembly <NUM> may restore the initial state as shown in <FIG>. When a compressive force is applied to the second longitudinal member <NUM>, a remaining portion of the frame assembly <NUM> except for the second longitudinal member <NUM> may be maintained without being deformed. In the above structure, the frame assembly <NUM> may assist a motion of a joint that moves in one direction, for example, a knee joint or an elbow joint.

<FIG> illustrates an initial state of a frame assembly according to at least one example embodiment, and <FIG> illustrates an operation of the frame assembly when one of longitudinal members of the frame assembly is pulled according to at least one example embodiment.

Referring to <FIG> and <FIG>, a frame assembly <NUM> may include a first object <NUM>, a second object <NUM>, a first longitudinal member <NUM>, a second longitudinal member <NUM>, and a plurality of distance maintaining members <NUM>.

The first longitudinal member <NUM> and the second longitudinal member <NUM> may initially have curved shapes when viewed from the front as shown in <FIG>. For example, the first longitudinal member <NUM> may include an elastic material that restores the original shape when an external force is not applied. The first object <NUM> may include a first slider <NUM> configured to slide relative to the second longitudinal member <NUM>. A distance maintaining member <NUM> may include a second slider <NUM> configured to slide relative to the second longitudinal member <NUM>.

Both end portions of the first longitudinal member <NUM> may be fixed to the first object <NUM> and the second object <NUM>, respectively. The first longitudinal member <NUM> may include a material that is flexible while having a stiffness sufficient to prevent buckling by a self-weight, for example, a material such as synthetic resin. For example, the first longitudinal member <NUM> may be provided in a shape of a plate with a side facing the second longitudinal member <NUM>.

One end portion of the second longitudinal member <NUM> may be fixed to the second object <NUM>, and another end portion of the second longitudinal member <NUM> may be connected to the first object <NUM> to move in a direction intersecting a longitudinal direction of the first object <NUM>. The second longitudinal member <NUM> may include a flexible material, and need not necessarily have a stiffness sufficient to prevent buckling. For example, the second longitudinal member <NUM> may be a cable to be inserted into recesses or holes formed in the first slider <NUM> and the second slider <NUM>.

In the above structure, the frame assembly <NUM> may be used as a motion assistance device for a joint that performs a flexion motion as shown in <FIG> or an extension motion as shown in <FIG>.

The flexion motion or the extension motion may be performed by a force applied to the second longitudinal member <NUM>. For example, in a case in which the first longitudinal member <NUM> is an elastic body and has an initial state as shown in <FIG>, the extension motion as shown in <FIG> may be performed when the second longitudinal member <NUM> is pulled, and the flexion motion as shown in <FIG> may be performed by an elastic restoring force when the force to pull the second longitudinal member <NUM> is released.

By adjusting heights of the plurality of distance maintaining members <NUM>, a maximum extension angle of the frame assembly <NUM> may be restricted. For example, in the structure as shown in <FIG> and <FIG>, the maximum extension angle of the frame assembly <NUM> may be restricted not to exceed <NUM> degrees.

Referring to <FIG> and <FIG>, a frame assembly <NUM> may include a first object <NUM>, a second object <NUM>, a first longitudinal member <NUM>, a second longitudinal member <NUM>, and a plurality of distance maintaining members <NUM>. The first object <NUM> and each distance maintaining member <NUM> may include a first slider <NUM> and a second slider <NUM>, respectively.

The first longitudinal member <NUM> and the second longitudinal member <NUM> may initially have straight shapes when viewed from the front as shown in <FIG>.

As shown in <FIG>, when a tensile force is applied to the second longitudinal member <NUM>, the frame assembly <NUM> may perform a flexion motion. As shown in <FIG>, when the tensile force applied to the second longitudinal member <NUM> is released, the frame assembly <NUM> may perform an extension motion.

A height of at least one of the plurality of distance maintaining members <NUM> may decrease from the first longitudinal member <NUM> toward the second longitudinal member <NUM>. For example, at least one of the plurality of distance maintaining members <NUM> may be provided in a trapezoidal shape. A portion corresponding to a bottom base of the trapezoidal shape may be fixed to the first longitudinal member <NUM>, and a portion corresponding to a top base of the trapezoidal shape may be slidably connected to the second longitudinal member <NUM>. A height of a portion of at least one distance maintaining member <NUM> connected to the second longitudinal member <NUM> may less than a height of a portion of the at least one distance maintaining member <NUM> connected to the first longitudinal member <NUM>. For example, the at least one distance maintaining member <NUM> may have a wedge shape with a height decreasing toward the second longitudinal member <NUM>. In the above structure, a maximum flexion angle of the frame assembly <NUM> may be restricted.

<FIG> is a side view illustrating a motion assistance apparatus according to at least one example embodiment, and <FIG> is a front view illustrating the motion assistance apparatus according to at least one example embodiment.

Referring to <FIG> and <FIG>, a motion assistance apparatus <NUM> may be worn by a user to assist a motion of the user. The user may correspond to a human, an animal, or a robot. However, the user is not limited thereto. Although <FIG> and <FIG> illustrate a case in which the motion assistance apparatus <NUM> assists a motion of a knee of the user, the motion assistance apparatus <NUM> may also assist a motion of another portion in an upper body, for example, a wrist or an elbow of the user, or a motion of another portion in a lower body, for example, an ankle of the user. The motion assistance apparatus <NUM> may assist a motion of a portion of the user. Hereinafter, a case in which the motion assistance apparatus <NUM> assists a motion of a knee of a human will be described. However, example embodiments are not limited thereto.

The motion assistance apparatus <NUM> may include a first wearable portion <NUM> and a second wearable portion <NUM> that are disposed on opposite sides from a joint of the user, a frame assembly <NUM> connected between the first wearable portion <NUM> and the second wearable portion <NUM>, and an actuator M to operate the frame assembly <NUM>.

The first wearable portion <NUM> may support a portion of the user. The first wearable portion <NUM> may include, for example, a detachable belt to support the entire circumference of a thigh above the knee of the user. Similarly, the second wearable portion <NUM> may also include a belt to support a circumference of a shin above the ankle of the user. The first wearable portion <NUM> and the second wearable portion <NUM> may fix a first object <NUM> and a second object <NUM> of the frame assembly <NUM> to a body of the user.

For ease of description, the first wearable portion <NUM> and the first object <NUM> are illustrated as separate elements. However, the first wearable portion <NUM> and the first object <NUM> may be provided as an integral body. Further, the first object <NUM> may perform the function of the first wearable portion <NUM>. The above description may also apply to the second wearable portion <NUM> and the second object <NUM>.

The frame assembly <NUM> may transfer, to the user, a torque to relatively rotate the thigh and a calf connected to the knee joint of the user. The frame assembly <NUM> may include a first longitudinal member <NUM> fixed to the first object <NUM> and the second object <NUM>, a second longitudinal member <NUM> slidably connected to the first object <NUM> and fixed to the second object <NUM>, and a plurality of first distance maintaining members <NUM>. The second longitudinal member <NUM> may operate to be wound or unwound on an outer circumferential surface of a rotary body rotated by the actuator M.

The frame assembly <NUM> may further include a third longitudinal member (not shown) configured to connect the first object <NUM> and the second object <NUM> and disposed on an opposite side of the first longitudinal member <NUM> from the knee joint of the user, a fourth longitudinal member (not shown) configured to connect the first object <NUM> and the second object <NUM> and disposed on an opposite side of the second longitudinal member <NUM> from the knee joint of the user, and second distance maintaining members <NUM> fixed to the third longitudinal member and slidably connected to the fourth longitudinal member. The fourth longitudinal member may operate to be wound or unwound on the outer circumferential surface of the rotary body rotated by the actuator M. It is possible to assist a motion of a joint more stably using the frame assembly <NUM> provided in a structure having symmetry on both sides from a single joint. Meanwhile, the fourth longitudinal member may be connected to another actuator, rather than the actuator M to which the second longitudinal member <NUM> is connected, thereby operating independently of the second longitudinal member <NUM>.

The actuator M may be connected to the second longitudinal member <NUM> and/or the fourth longitudinal member, and operate the frame assembly <NUM>. The actuator M may be attached directly to the user, or indirectly to the user by being fixed to a portion of the motion assistance apparatus <NUM>. In another example embodiment, the actuator M may be carried by the user, rather than being fixed separately. A position of the actuator M is not limited thereto.

Hereinafter, a case in which the frame assembly <NUM> has a flexion state as an initial state, as shown in <FIG>, will be described. The frame assembly <NUM> may perform a flexion motion or an extension motion based on a direction in which the rotary body is rotated by the actuator M.

When the rotary body rotates in a clockwise direction in <FIG> while the knee the user is in a flexion state as shown in <FIG>, the second longitudinal member <NUM> and/or the fourth longitudinal member may be pulled, and a torque to rotate the second object <NUM> relative to the first object <NUM> in a clockwise direction may be applied to the second object <NUM>. Through the above operation, the frame assembly <NUM> may perform the extension motion, and thus the motion assistance apparatus <NUM> may assist the user to extend a leg, for example, to stand up. By transferring a sufficient power to the actuator M, the motion assistance apparatus <NUM> may help the user to continuously stand erect. By wedge shapes of the first distance maintaining members <NUM> and/or the second distance maintaining members <NUM>, a maximum extension angle of the frame assembly <NUM> may be restricted not to exceed a maximum extension angle of the knee joint of the user. Thus, although a power exceeding a power to maintain the user to stand erect is applied to the second longitudinal member <NUM>, damage to the knee joint of the user may be prevented.

Conversely, when the rotary body rotates in a counterclockwise direction while the knee of the user is in an extension state as shown in <FIG>, the second longitudinal member <NUM> may be released and a magnitude of the torque applied to the second object <NUM> may be reduced. In this example, by an elastic restoring force of the first longitudinal member <NUM> and/or the third longitudinal member, a torque to rotate the second object <NUM> relative to the first object <NUM> in a counterclockwise direction may be applied to the second object <NUM>. Through the above operation, the frame assembly <NUM> may perform a flexion motion. Thus, the motion assistance apparatus <NUM> may assist the user to bend a leg, for example, to sit down. Meanwhile, the frame assembly <NUM> may have a flexion state as an initial state, and thus the actuator M may not need to operate while the user is sitting, whereby energy may be saved.

The frame assembly <NUM> of the motion assistance apparatus <NUM> may be flexible with respect to a force applied in a lateral direction as described above, and thus may be deformed to be suitable for changes in a body shape of the user corresponding to various motion states. Thus, although the frame assembly <NUM> is in close contact with the user, negative effects on wearability may be minimized. Since the frame assembly <NUM> may not need to be designed to be spaced apart from a body of the user to prevent an issue of friction, a space required to install the frame assembly <NUM> may be reduced and the entire motion assistance apparatus <NUM> may be worn under clothing.

Meanwhile, a portion of joints of the user may simultaneously roll and slide, and thus a simple ball joint type may not prevent a misalignment and transfer an unnecessary load to the user. That is, since a center of rotation of an actual joint of the user changes, whereas a center of rotation of a ball joint is fixed, conventionally, the unnecessary load may be transferred to the user due to the misalignment. The unnecessary load may decrease a user wearability, and cause deformation of the ball joint and components connected to the ball joint. Hereinafter, the misalignment will be described in detail based on a knee joint of a human body, and advantages of using a frame assembly according to at least one example embodiment as a joint device will be described.

<FIG> illustrates a flexion motion of a knee joint of a user.

Referring to <FIG>, a knee joint of a user may simultaneously perform a rolling motion and a sliding motion while the user bends and stretches a knee. When a thigh or a calf of the user pivots about the knee joint, a center of rotation of the knee joint of the user may change. For example, a thighbone P may perform a rolling motion on a shin bone R. In conjunction with the rolling motion, an end surface P1 of the thighbone P may slide along an end surface R1 of the shin bone R. Thus, a center of rotation of the rolling motion of the thighbone P may change from an initial contact point C1 to a subsequent contact point C2.

As shown in <FIG>, the center of rotation of the actual joint of the user may change during a motion process, and thus the simple ball joint type may not imitate such a motion exactly. However, a center of rotation of a frame assembly according to at least one example embodiment is not fixed unlike the ball joint type, and thus may be used to imitate the motions of the actual joint. Hereinafter, descriptions will be provided further with reference to the drawings.

<FIG> illustrates a shape of a frame assembly when a knee of a user is in a flexion state according to at least one example embodiment, and <FIG> illustrates a shape of the frame assembly when the knee of the user is in an extension state according to at least one example embodiment. Hereinafter, the first object <NUM> may perform the function of the first wearable portion <NUM> of <FIG>, and the second object <NUM> may perform the function of the second wearable portion <NUM> of <FIG>.

Referring to <FIG> and <FIG>, the frame assembly <NUM> may include the plurality of distance maintaining members <NUM>. Each distance maintaining member <NUM> may rotate relative to another adjacent distance maintaining member <NUM>, and thus the frame assembly <NUM> may have a plurality of centers of rotation corresponding to a number of the distance maintaining members <NUM>. Further, since the frame assembly <NUM> has a flexibility with respect to a force applied in a lateral direction, the frame assembly <NUM> may be self-deformed to a shape that reduces (or, alternatively, minimizes) an internal stress, by the external force applied to the frame assembly <NUM>. Thus, the frame assembly <NUM> may be self-aligned such that a momentary center of rotation between the first object <NUM> and the second object <NUM> may match a momentary center of rotation of a knee joint of the user.

When the knee of the user is in a flexion state as shown in <FIG>, the center of rotation of the knee joint may be the contact point C1 as shown in <FIG>. When the user moves in a state in which the center of rotation of the frame assembly <NUM> does not match the contact point C1, a misalignment may cause an external force to be applied to the frame assembly <NUM>. The external force may deform the frame assembly <NUM> which is flexible with respect to a force applied in a lateral direction, thereby matching the center of rotation between the first object <NUM> and the second object <NUM> with the contact point C1.

Similarly, when the knee of the user is in an extension state as shown in <FIG>, the center of rotation of the knee joint may change to the contact point C2 as shown in <FIG>. In this example, the external force applied to the frame assembly <NUM> may change. The external force may deform the frame assembly <NUM>, thereby matching the center of rotation between the first object <NUM> and the second object <NUM> with the contact point C2.

The frame assembly <NUM> may have a flexibility and a multi-degree of freedom through the flexible first longitudinal member <NUM>, the second longitudinal member <NUM>, and the plurality of distance maintaining members <NUM>, and thus may solve an issue of misalignment.

<FIG> illustrates a frame assembly being worn by a user according to at least one example embodiment, and <FIG> illustrates the frame assembly being worn by the user at a position different from a position shown in <FIG> according to at least one example embodiment.

For example, to utilize the plurality of distance maintaining members <NUM> uniformly, a center of the frame assembly <NUM> may be matched with a joint of a user. However, referring to <FIG> and <FIG>, the frame assembly <NUM> may perfectly operate without causing a misalignment simply through rough positioning.

Referring to <FIG>, the center of the frame assembly <NUM> is positioned on a lower side than the joint. In this example, a gap between distance maintaining members <NUM> positioned relatively close to an upper body of the user may increase further, whereby the frame assembly <NUM> may operate normally as a joint device.

Referring to <FIG>, the center of the frame assembly <NUM> is positioned on an upper side than the joint. In this example, a gap between distance maintaining members <NUM> positioned relatively close to a lower body of the user may increase further, whereby the frame assembly <NUM> may operate normally as a joint device.

A motion assistance apparatus including a general rotary joint faces a decrease in wearability and damage to the apparatus due to a misalignment when an axis of rotation of the rotary joint does not match an axis of rotation of a joint of a user. However, the motion assistance apparatus <NUM> may be worn on any portion of the user, and thus may be worn easily.

<FIG> illustrates a motion assistance apparatus according to at least one example embodiment.

Referring to <FIG>, a motion assistance apparatus <NUM> may assist a motion of an ankle joint. The motion assistance apparatus <NUM> may include a first object <NUM> configured to support a portion of a user, for example, a front side of a shin, a second object <NUM> configured to support another portion of the user, for example, a sole, and a frame assembly <NUM> that includes a first longitudinal member <NUM> configured to connect the first object <NUM> and the second object <NUM>, a second longitudinal member <NUM> spaced apart from the first longitudinal member <NUM>, and a plurality of distance maintaining members <NUM> connected between the first longitudinal member <NUM> and the second longitudinal member <NUM>.

When the second longitudinal member <NUM> is pulled, a gap between the plurality of distance maintaining members <NUM> may decrease and the second object <NUM> may rotate relative to the first object <NUM> in a counterclockwise direction, whereby the user may perform a push-off motion. Conversely, when a force to pull the second longitudinal member <NUM> is released, the gap between the plurality of distance maintaining members <NUM> may increase by an elastic restoring force of the first longitudinal member <NUM>, whereby the user may return to the original state.

Meanwhile, an axis of rotation of a portion of joints of the user may change based on an eversion motion or an inversion motion. A simple ball joint type may not prevent a misalignment and transfer an unnecessary load to the user. Hereinafter, the misalignment will be described in detail based on an ankle joint of a human body, and advantages of using a frame assembly according to at least one example embodiment as a joint device will be described.

<FIG> illustrates an eversion motion of an ankle joint of a user, and <FIG> illustrates an inversion motion of the ankle joint of the user.

Referring to <FIG> and <FIG>, an ankle of the user may perform an eversion motion that bends outward from a center of the user, and an inversion motion that bends inward from the center of the user. Based on the motions, axes of rotation of a flexion motion and an extension motion of the ankle may change as well. In detail, when the ankle performs the eversion motion as shown in <FIG>, the axes of rotation of the flexion/extension motions of the ankle may change to slant downward toward the center of the user. Conversely, when the ankle performs the inversion motion as shown in <FIG>, the axes of rotation of the flexion/extension motions of the ankle may change to slant upward toward the center of the user.

As shown in <FIG> and <FIG>, a center of rotation of an actual joint of a user may change during a motion process, and thus the simple ball joint type may not imitate such a motion exactly. However, a center of rotation of the frame assembly <NUM> is not fixed unlike the ball joint type, and thus may be used to imitate the motions of the actual joint. Hereinafter, descriptions will be provided further with reference to the drawings.

<FIG> illustrates a shape of a frame assembly when an ankle joint of a user is in a neutral state according to at least one example embodiment, and <FIG> illustrates a shape of the frame assembly when the ankle joint of the user is in an eversion motion state according to at least one example embodiment. <FIG> is an enlarged view of a shape of a portion B of <FIG>.

For better understanding, descriptions will be provided based on a case in which angles between all the distance maintaining members <NUM> of the frame assembly <NUM> are equal while an ankle joint is in a neutral state as shown in <FIG>.

When the ankle joint performs an eversion motion, a lateral center of rotation of an ankle may move upward as shown in <FIG>. Conversely, a medial center of rotation of the ankle may move downward. In this example, among a plurality of distance maintaining members <NUM> positioned lateral to the ankle joint, a gap between distance maintaining members <NUM> positioned on a relatively upper side may increase further than a gap between distance maintaining members <NUM> positioned on a relatively lower side, whereby the frame assembly <NUM> may be self-aligned to cope with a change in the lateral center of rotation of the ankle. In detail, among the plurality of distance maintaining members <NUM>, a gap between distance maintaining members <NUM> positioned relatively close to the center of rotation may increase further than a gap between distance maintaining members <NUM> positioned relatively distant from the center of rotation, whereby the center of rotation of the frame assembly <NUM> may change. Thus, a user wearability may improve and an unnecessary load to be applied to the user may be reduced (or, alternatively, prevented).

The frame assembly <NUM> may be provided in a structure having symmetry on both sides from the ankle joint, similar to the frame assembly <NUM> of <FIG>. Distance maintaining members respectively provided on both sides may be self-aligned separately. Thus, an issue of misalignment caused by the eversion/inversion motions as shown in <FIG> and <FIG> may be solved.

The frame assembly <NUM> may have a flexibility and a multi-degree of freedom through the flexible first longitudinal member <NUM>, the second longitudinal member <NUM>, and the plurality of distance maintaining members <NUM>, and thus may solve the issue of misalignment.

In some example embodiments, the motion assistance apparatus <NUM>, <NUM> may include a at least one sensor (not shown) and a controller (not shown).

The sensor may be a pressure sensor, a strain sensor or any other sensor configured to sense movement of the user and/or an angle of a joint of the user.

The controller may include a processor and a memory. The memory may include may include a non-transitory computer readable medium. Examples of non-transitory computer-readable media include magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD ROM discs and DVDs; magneto-optical media such as optical discs; and hardware devices that are specially configured to store and perform program instructions, such as read-only memory (ROM), random access memory (RAM), flash memory, and the like. The non-transitory computer-readable media may also be a distributed network, so that the program instructions are stored and executed in a distributed fashion. The processor may processor may be an arithmetic logic unit, a digital signal processor, a microcomputer, a field programmable array, a programmable logic unit, a microprocessor or any other device capable of responding to and executing instructions in a defined manner. The memory may contain computer readable code that, when executed by the processor, configures the processor as a special purpose computer.

For example, the memory may contain computer readable code that, when executed by the processor, configures the processor as a special purpose computer to determine if the user is performing a flexion motion to, for example, sit down or an extension motion to, for example, stand up, based on information from the sensor. Further, the processor may control the actuator M to rotate the actuator M in different directions based on the determination. For example, in some example embodiments, the controller may instruct the actuator M to rotate in a counter-clockwise direction when the user is sitting down, and instruct the actuator M to rotate M in a clockwise direction when the user is standing up.

Claim 1:
A motion assistance apparatus (<NUM>, <NUM>) comprising:
a first object (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured to attach to a first portion of a user;
a second object (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured to attach to a second portion of the user;
a frame assembly (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) including,
a first longitudinal member (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured to connect the first object and the second object,
a second longitudinal member (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) spaced apart from the first longitudinal member; and
a plurality of distance maintaining members (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) connecting the first longitudinal member and the second longitudinal member, the plurality of distance maintaining members configured to maintain a distance between the first longitudinal member and the second longitudinal member, wherein at least one of the plurality of distance maintaining members has a first end portion and a second end portion with an intermediate portion there between, wherein the first end portion is fixed or slidably connected to the first longitudinal member, and wherein the second end portion is fixed or slidably connected to the second longitudinal member;
characterized in that a height of said second end portion between the first object and the second object is less than a height of said first end portion to restrict a maximum flexion angle of the frame assembly.