Lift-assist band with gradient strength

Abstract

An example lift-assist band, a lift-assist harness comprising a lift-assist band, and a method for manufacturing a lift-assist band are provided. The example lift-assist band includes a first band portion and a second band portion. The first band portion including a first elastic material associated with a first elastic material strength. The second band portion includes two layers. The first layer comprising a second elastic material associated with a second elastic material strength, wherein the first elastic material strength is greater than the second elastic material strength. The second layer comprising an inelastic material, wherein in a rest state, a second layer length associated with the second layer is greater than a first layer length associated with the first layer.

Description

LTFT-ASSTST BAND WITH GRADIENT STRENGTHCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of Chinese Application No.202510299655.1, filed March 13, 2025, the entire contents of which are incorporated herein by reference.TECHNOLOGICAL FILED

[0002] Embodiments of the present disclosure relate generally to lift-assist bands, and more specifically to lift-assist bands associated with a lift-assist harnessBACKGROUND

[0003] Many tasks require handling heavy loads. Occupations that require repetitive load handling may lead to musculoskeletal injuries due to the constant strain placed on muscles, joints, and connective tissues. When workers repeatedly handle heavy loads, especially with inadequate rest, the repetitive strain increases the risk of muscle fatigue, ligament sprains, and injuries. The risk is further heightened if handling involves awkward positions, excessive force, or prolonged assertion without sufficient recovery. As such, musculoskeletal disorders account for a significant proportion of work-related injuries and illnesses. For these reasons, safety harnesses have been developed to ensure proper posture or otherwise assist in the handling of heavy loads.

[0004] Applicant has identified many technical challenges and difficulties associated with liftassist mechanisms. Through applied effort, ingenuity, and innovation, Applicant has solved problems related to left-assist mechanisms by developing solutions embodied in the present disclosure, which are described in detail below.BRIEF SUMMARY

[0005] Various embodiments are directed to an example lift-assist band, a lift-assist harness comprising a lift-assist band, and a method for manufacturing a lift-assist band.

[0006] An example lift-assist band is provided. The example lift-assist band comprising a first band portion and a second band portion. The first band portion comprising a first elastic material associated with a first elastic material strength. The second band portion comprising two layers. The first layer comprising a second elastic material associated with a second elastic materialstrength, wherein the first elastic material strength is greater than the second elastic material strength. The second layer comprising an inelastic material, wherein in a rest state, a second layer length associated with the second layer is greater than a first layer length associated with the first layer.

[0007] In some embodiments, the first layer of the second band portion further comprises a first layer first end and a first layer second end. In some embodiments, the second layer of the second band portion further comprises a second layer first end; and a second layer second end. The first layer first end is aligned with the second layer first end, and the first layer second end is aligned with the second layer second end, such that a separation gap is defined between the first layer and the second layer.

[0008] In some embodiments, the lift-assist band comprises a first band strength when deformed below an extension threshold, and a second band strength when deformed above the extension threshold.

[0009] In some embodiments, the extension threshold is dependent on a layer ratio between the first layer length and the second layer length.

[0010] In some embodiments, the layer ratio is greater than or equal to 0.5 and less than 1.0.

[0011] In some embodiments, the lift-assist band comprises a plurality of sequential second band portions.

[0012] In some embodiments, the first elastic material strength is between 0.5 and 10 newtons per millimeter.

[0013] In some embodiments, the second elastic material strength is between 0.5 and 10 newtons per millimeter.

[0014] An example lift-assist harness is provided. The example lift-assist harness comprises a waist strap, a back portion, and a lift-assist band. The waist strap configured to attach around a waist of a user. The back portion comprising a first end and a second end, wherein the first end is attached to the waist strap. The lift-assist band attached to the second end of the back portion, wherein the lift-assist band is positioned to track over a shoulder of the user and attach to a portion of an arm of the user. The lift-assist band comprising a first band portion and a second band portion. The first band portion comprising a first elastic material associated with a first elastic material strength. The second band portion comprising two layers. The first layer comprising a second elastic material associated with a second elastic material strength, wherein the first elastic materialstrength is greater than the second elastic material strength. The second layer comprising an inelastic material, wherein a second layer length associated with the second layer is greater than a first layer length associated with the first layer.

[0015] In some embodiments, the first layer of the second band portion further comprises a first layer first end and a first layer second end. In some embodiments, the second layer of the second band portion further comprises a second layer first end and a second layer second end. Wherein the first layer first end is aligned with the second layer first end, and wherein the first layer second end is aligned with the second layer second end, such that a separation gap is defined between the first layer and the second layer.

[0016] In some embodiments, the lift-assist band comprises a first band strength when deformed below an extension threshold, and a second band strength when deformed above the extension threshold.

[0017] In some embodiments, the extension threshold is dependent on a layer ratio between the first layer length and the second layer length.

[0018] In some embodiments, the layer ratio is greater than or equal to 0.5 and less than 1.0.

[0019] In some embodiments, the lift-assist band comprises a plurality of sequential second band portions.

[0020] In some embodiments, the first elastic material strength is between 0.9 and 1.1 newtons per millimeter.

[0021] In some embodiments, the second elastic material strength is between 1.9 and 2.1newtons per millimeter.

[0022] A method of manufacturing a lift-assist band is further provided. In some embodiments, the method comprising providing a first band portion comprising a first elastic material associated with a first elastic material strength; attaching a first layer comprising a second elastic material associated with a second elastic material strength to a second layer comprising an inelastic material, to produce a second band portion, wherein the first elastic material strength is greater than the second elastic material strength, and wherein a second layer length associated with the second layer is greater than a first layer length associated with the first layer; and attaching the second band portion to the first band portion.

[0023] In some embodiments, the first layer of the second band portion further comprises a first layer first end and a first layer second end. In some embodiments, the second layer of thesecond band portion further comprises a second layer first end; and a second layer second end. Wherein attaching the first layer to the second layer comprises: aligning the first layer first end with the second layer first end; attaching the first layer first end with the second layer first end; aligning the first layer second end with the second layer second end; and attaching the first layer second end with the second layer second end, forming a separation gap between the first layer and the second layer.

[0024] In some embodiments, the lift-assist band comprises a first band strength when deformed below an extension threshold, and a second band strength when deformed above the extension threshold.

[0025] In some embodiments, the extension threshold is dependent on a layer ratio between the first layer length and the second layer length.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Reference will now be made to the accompanying drawings. The components illustrated in the figures may or may not be present in certain embodiments described herein. Some embodiments may include fewer (or more) components than those shown in the figures in accordance with an example embodiment of the present disclosure.

[0027] FIG. 1 depicts an example lift-assist harness comprising a gradient strength lift-assist band in accordance with an example embodiment of the present disclosure.

[0028] FIG. 2 depicts a perspective view of an example portion of a lift-assist band in accordance with an example embodiment of the present disclosure.

[0029] FIG. 3 depicts a side-view of an example bounded elastic section of a lift-assist band in accordance with an example embodiment of the present disclosure.

[0030] FIG. 4 illustrates a perspective view of an example mechanism for attaching an elastic portion and a flex portion of a lift-assist band in accordance with an example embodiment of the present disclosure.

[0031] FIG. 5 provides a graph illustrating an example strength of a gradient strength lift-assist band relative to an extension length in accordance with an example embodiment of the present disclosure.

[0032] FIG. 6 illustrates an example method for manufacturing a gradient strength lift-assist band in accordance with an example embodiment of the present disclosure.DETAILED DESCRIPTION

[0033] Example embodiments will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the inventions of the disclosure are shown. Indeed, embodiments of the disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

[0034] Various example embodiments of the present disclosure address technical problems associated with the elastic strength of lift-assist bands by providing a gradient strength lift-assist band. As understood by those of skill in the field to which the present disclosure pertains, there are numerous example scenarios in which a user may benefit from a lift-assist band having a gradient strength.

[0035] For example, many tasks require handling heavy loads. Occupations that require repetitive load handling may lead to musculoskeletal injuries due to the constant strain placed on muscles, joints, and connective tissues. When workers repeatedly handle heavy loads, especially with inadequate rest, the repetitive strain increases the risk of muscle fatigue, ligament sprains, and injuries. The risk is further heightened if handling involves awkward positions, excessive force, or prolonged assertion without sufficient recovery. As such, musculoskeletal disorders account for a significant proportion of work-related injuries and illnesses.

[0036] Various lift-assist mechanisms have been developed to ensure proper ergonomics and / or aid users in the handling of heavy objects. Some example mechanisms involve utilizing elastic bands to aid in handling heavy objects. Unfortunately, to substantially lighten the load, elastic bands used as lift-assist mechanisms must have a strong elastic strength. An elastic band with strong elastic strength may be quite difficult for a user to stretch when initially picking up a heavy object. However, if the elastic strength of an elastic band used as a lift-assist mechanism is too weak, the elastic band does not provide enough strength to lighten the burden of the heavy load. Thus, there is a need for a lift-assist mechanism comprising an elastic band with variable elastic strength based on the extension of the elastic band.

[0037] The various example embodiments described herein utilize various techniques to enable a gradient strength lift-assist band to aid users in the handling of heavy objects. For example, in some embodiments, the gradient strength lift-assist band may include an elastic portionmade of an elastic material having a first elastic material strength. In addition, the gradient strength lift-assist band may include a flex portion made up of one or more bounded elastic sections. Each bounded elastic section may include a first layer comprising an elastic material having a second elastic material strength, the second elastic material strength being less than the first elastic material strength. The bounded elastic sections may further include a second layer comprising an inelastic material, attached to the second elastic material. Each second layer of inelastic material may be longer than the associated elastic material of the first layer, such that a separation gap is formed between the first layer of elastic material and the second layer of inelastic material. The ratio of the length of the second layer of the flex portion of the gradient strength lift-assist band to the first layer of the flex portion of the gradient strength lift-assist band may be referred to as the layer ratio and may define the elastic strength properties of the gradient strength lift-assist band.

[0038] A gradient strength lift-assist band utilizing an elastic portion, and a flex portion results in a gradient strength lift-assist band having two different elastic strengths based on the extension of the gradient strength lift-assist band. For example, a first band strength may be correlated with the weaker elastic strength first layer elastic material of the flex portion of the gradient strength lift-assist band. Once the extension of the gradient strength lift-assist band exceeds an extension threshold, the gradient strength lift-assist band may be associated with a second band strength, wherein the second band strength is correlated with the stronger elastic strength of the elastic portion of the gradient strength lift-assist band. Further, the extension threshold may be defined based on the layer ratio corresponding to the ratio of the length of the inelastic second layer of the flex portion of the gradient strength lift-assist band to the length of the elastic first layer of flex portion of the gradient strength lift-assist band.

[0039] As a result of the herein described example embodiments, lift-assist mechanisms may be greatly improved. For example, the gradient strength lift-assist band of the present disclosure may enable a user to more easily stretch the gradient strength lift-assist band when initially picking up an object while still providing adequate strength to lighten the burden of the heavy load.

[0040] Referring now to FIG. 1, an example lift-assist harness 100 comprising a gradient strength lift-assist band 108 is provided. As depicted in FIG. 1, the lift-assist harness 100 comprises a waist strap 102, a back portion 104, a shoulder strap attachment 106, and a plurality of lift-assist bands 108.

[0041] As depicted in FIG. 1, the back portion 104 provides support to the spine of the user 116. The back portion attaches to a waist strap 102 at end 104a and the shoulder strap attachment 106 at end 104b. In addition, the back portion 104 attaches to a chest strap 122. The waist strap 102 is positioned to wrap around the waist of a user 116 and provide additional support at the lower back. The chest strap 122 is positioned to wrap around the chest of the user 116 and keep the back portion 104 and shoulder strap attachment 106 in place. The shoulder strap attachment 106 attaches each of the one or more lift-assist bands 108 to the lift-assist harness 100. In some embodiments, the shoulder strap attachment 106 may comprise a sleeve configured to receive each of the one or more lift-assist bands 108.

[0042] As further depicted in FIG. 1, the lift-assist harness 100 comprises a gradient strength lift-assist band 108 attached to the back portion 104 of the lift-assist harness 100 by the shoulder strap attachment 106. The depicted gradient strength lift-assist band 108 tracks over the shoulder 118 of the user 116 and attaches to the arm 120 of the user 116 at or near the hand. Although only one gradient strength lift-assist band 108 is depicted in FIG. 1, it will be appreciated that a second gradient strength lift-assist band 108 may track over the other shoulder of the user from the shoulder strap attachment 106 and attach to the other arm of the user 116.

[0043] The gradient strength lift-assist band 108 is configured to assist a user 116 in lifting and / or handling a load 114. For example, the gradient strength lift-assist band 108 may be extended by the arm 120 of the user 116 as the arm is extended to pick up a load 114. Once the load 114 is picked up, the tension of the gradient strength lift-assist band 108 may bear a portion of the weight of the load 114 through the lift-assist harness 100. Such redistribution of the weight of the load 114 may reduce the strain placed on muscles, joints, and connective tissues of the user, decreasing the risk of repetitive strain, muscle fatigue, ligament sprains, and other injuries.

[0044] As further depicted in FIG. 1, the gradient strength lift-assist band 108 comprises a flex portion 110 and an elastic portion 112. The elastic portion 112 comprises any elastic material configured to deform under an applied force and return to its original shape once the force is removed. In some embodiments, the elastic portion 112 may comprise rubber, spandex fiber, elastane, certain polymers, and other materials which exhibit flexibility and resilience due to their molecular structure.

[0045] In general, an elastic material (e.g., elastic portion 112) may be associated with an elastic strength. Elastic strength (e.g., elastic material strength) refers to the ability of a material towithstand deformation under force and return to its original shape without permanent damage when stress is removed. Elastic strength quantifies the stiffness of a material and may be expressed as the ratio of force (e.g., in Newtons) to extension (e.g., in millimeters). Thus, as the extension of the elastic material increases within the materials elastic limit, the force to resist elastic deformation changes relative to the elastic ratio. In some embodiments, the elastic strength of the elastic portion 112 may be between 0.5 and 10 Newtons per millimeter.

[0046] As further depicted in FIG. 1, the gradient strength lift-assist band 108 comprises a flex portion 110. The flex portion 110 comprises two layers, including a first elastic layer, and a second inelastic layer. In general, the elastic strength of the first elastic layer is smaller (e.g., weaker) than the elastic strength of the elastic portion 112. The flex portion 110 stretches in accordance with the elastic strength of the first elastic layer until the inelastic layer is fully extended, at which point the flex portion 110 becomes inelastic. The flex portion 110 is further described in relation to FIG.2 - 3.

[0047] Referring now to FIG. 2, an example gradient strength lift-assist band 108 is provided. As depicted in FIG. 2, the gradient strength lift-assist band 108 includes an elastic portion 112 and a flex portion 110 attached to the end 112b of the elastic portion 112. The flex portion 110 comprises a plurality of bounded elastic sections 202 (e.g., second band portion). Each bounded elastic section 202 comprises an elastic material layer 204 (e.g., first layer) and an inelastic material layer. In some embodiments, one or both of the elastic material layer 204 and inelastic material layer 206 may be a continuous strip of material comprising each of the plurality of sequential bounded elastic sections 202 of the flex portion 110.

[0048] As depicted in FIG. 2, the flex portion 110 comprises a plurality of bounded elastic sections 202, each comprising an elastic material layer 204 and an inelastic material layer 206. The elastic material layer 204 comprises any elastic material configured to deform under an applied force and return to its original shape once the force is removed. In some embodiments, the elastic material layer 204 may comprise rubber, spandex fiber, elastane, certain polymers, and other materials which exhibit flexibility and resilience due to their molecular structure. The elastic material layer 204 is associated with an elastic strength. The elastic strength of the elastic material layer 204 of the bounded elastic section 202 is less than the elastic strength of the elastic portion 112 of the gradient strength lift-assist band 108. For example, in some embodiments, the elastic strength of the elastic material layer 204 may be 1.0 Newtons per millimeters, while the elasticstrength of the elastic portion 112 of the gradient strength lift-assist band 108 is 2. 0 Newtons per millimeter. In this way, the gradient strength lift-assist band 108 is associated with an elastic strength related to the elastic strength of the elastic material layer 204 during an initial tension period. In some embodiments, the thickness of the elastic material layer 204 is also less than the thickness of the elastic portion 112. In some embodiments, the elastic strength of the elastic material layer 204 may be between 0.5 and 10 newtons per millimeter.

[0049] As further depicted in FIG. 2, each bounded elastic section 202 comprises an inelastic material layer 206 attached to the elastic material layer 204. The inelastic material layer 206 comprises any inelastic material, for example a woven tech such as nylon, polyethylene terephthalate (PET), polypropylene (PP), and / or polyethylene (PE). In some embodiments, the inelastic material may comprise a synthetic fiber, such as aramid, a High Molecular Weight Polyethylene (HMWPE), a glass fiber, a basalt fiber, a carbon fiber, and / or any hybrid combination thereof. As depicted in FIG. 2, the inelastic material is bunched throughout the flex portion 110. Thus, when a force is applied to stretch the gradient strength lift-assist band 108 the elastic material layer 204 extends until the inelastic material layer 206 is fully extended. Once the inelastic material layer 206 is fully extended, the flex portion 110 no longer extends. Instead, the elastic portion 112 extends and the gradient strength lift-assist band 108 exhibits an elastic strength based on the elastic strength of the elastic portion 112.

[0050] Referring now to FIG. 3, an example bounded elastic section 202 is provided. As described in relation to FIG. 2, a flex portion 110 of a gradient strength lift-assist band 108 may comprise a plurality of sequential bounded elastic sections 202. The bounded elastic section 202 includes an elastic material layer 204 having a first end 204a and a second end 204b and associated with a first layer length 304. The bounded elastic section 202 further includes an inelastic material layer 206 comprising a first end 206a and a second end 206b and associated with a second layer length 302 which is greater than the first layer length 304.

[0051] As depicted in FIG. 3, the first layer length 304 associated with the elastic material layer 204 comprises the length of the elastic material layer 204 in a rest state (e.g., original form). Similarly, the second layer length 302 is the length of the inelastic material layer 206 in a rest state, however, since the inelastic material layer 206 is inelastic, the second layer length 302 remains relatively constant even when stretching force is applied to the inelastic material layer 206.

[0052] As further depicted in FIG. 3, the first end 204a of the elastic material layer 204 is attached to the first end 206a of the inelastic material layer 206. Similarly, the second end 204b of the elastic material layer 204 is attached to the second end 206b of the inelastic material layer 206. Due to the difference between the first layer length 304 in a rest state and the second layer length 302, a separation gap 306 is formed between the two layers. Although a single bounded elastic section 202 is depicted in FIG. 3, as shown in FIG. 2, a flex portion (e.g., flex portion 110 shown in FIG. 2) may comprise a plurality of sequential bounded elastic sections 202. When in a rest state, the plurality of sequential bounded elastic sections 202 form a series of bumps or ruffles comprising the inelastic material layer 206.

[0053] As depicted in FIG. 3, the second layer length 302 is greater than the first layer length 304 in a rest state. With the second layer length 302 greater than the first layer length 304, the elastic material layer 204 may extend when a stretching force is applied to one or more ends (e.g., end 204a, 204b) of the bounded elastic section 202. The elastic material layer 204 extends until the first layer length 304 is equivalent to the second layer length 302, at which point the bounded elastic section 202 becomes inelastic, due to the inelastic material layer 206. The point at which the bounded elastic section 202, or more particularly, the flex portion of the gradient strength liftassist band (e.g., flex portion 110 as depicted in FIG. 2), becomes inelastic due to the first layer length 304 extending to the second layer length 302 defines the extension threshold. For example, because the elastic strength of the elastic material layer 204 is less than the elastic strength of the elastic portion 112 of the gradient strength lift-assist band 108 (as shown in FIG. 2), the elastic strength of the gradient strength lift-assist band is defined by the elastic strength of the elastic material layer 204, until the extension threshold is reached. Once the extension threshold is reached, the elastic strength of the gradient strength lift-assist band 108 is defined by the elastic strength of the elastic portion 112 of the gradient strength lift-assist band 108. FIG. 5 further illustrates the strength of a gradient strength lift-assist band relative to an extension threshold.

[0054] The ratio of the second layer length 302 to the first layer length 304 in a resting state may be expressed as a layer ratio. In some embodiments, the layer ratio comprises the rest state second layer length 302 divided by the rest state first layer length 304. As described herein, the layer ratio may define the extension threshold, or the point at which the elastic strength of a gradient strength lift-assist band changes from the elastic strength of the elastic material layer 204 of the flex portion of the gradient strength lift-assist band to the elastic strength of the elasticportion of the gradient strength lift-assist band. Tn some embodiments, the layer ratio may be greater than 1.0 and less than or equal to 2.5; more preferably greater than 1.0 and less than or equal to 2.25; most preferably greater than 1.0 and less than or equal to 2.0.

[0055] Referring now to FIG. 4, a top view of an example gradient strength lift-assist band 108 is provided. As depicted in FIG. 4, the example gradient strength lift-assist band 108 includes an elastic portion 112 having a first end 112a and a second end 112b. The gradient strength liftassist band 108 further includes a flex portion 110 having a first end 110a and a second end 110b.

[0056] As depicted in FIG. 4, the flex portion 110 comprises a plurality of bounded elastic sections 202. Each bounded elastic section 202 is created by attaching a portion of the second inelastic material layer of the flex portion 110 of the gradient strength lift-assist band 108 to the underlying elastic material layer 204, for example, with a sewing line 404. In some embodiments, the elastic material layer (e.g., elastic material layer 204 as depicted in FIG. 2 - FIG. 3) may comprise one continuous band of material. In addition, the inelastic material layer (e.g., inelastic material layer 206 as depicted in FIG. 2 - FIG. 3) may comprise one continuous band of material. The inelastic material layer may be ruffled before being sewn, such that the inelastic material layer length (e.g., second layer length 302 as shown in FIG. 3) of the inelastic material layer is greater than the elastic material layer length (e.g., first layer length 304 as shown in FIG. 3) of the elastic material layer in a rest state at each bounded elastic section 202.

[0057] As further depicted in FIG. 4, the second end 112b of the of the elastic portion 112 is sewn to the first end 110a of the flex portion 110 of the gradient strength lift-assist band 108 with sewing line 402. The sewing line 402 thus attaches three layers of material, the elastic material layer of the flex portion 110, the elastic portion 112, and the inelastic material layer of the flex portion 110 of the gradient strength lift-assist band 108.

[0058] Referring now to FIG. 5, an example graph 550 illustrating the elastic force of an example gradient strength lift-assist band (e.g., gradient strength lift-assist band 108) relative to an extension length of the gradient strength lift-assist band is depicted.

[0059] As depicted in FIG. 5, the elastic force comprises the force exerted by a deformed elastic band to return to an original form. Elastic force may be equivalently described as the force required to extend the elastic band to the corresponding extension. Extension is the distance beyond the original form an elastic band is stretched. Thus, the elastic strength of an elastic material may be viewed as a slope represented by the elastic force over the extension.

[0060] As depicted in FIG. 5, the example gradient strength lift-assist band comprises two distinct elastic strengths (e.g., slopes), the flex portion elastic strength 504 and the elastic portion elastic strength 506. The flex portion elastic strength 504 is based on the elastic strength of the elastic material layer of the flex portion of the gradient strength lift-assist band. Since the elastic material layer of the flex portion of the gradient strength lift-assist band comprises a weaker elastic strength than the elastic portion of the gradient strength lift-assist band, the elastic material layer of the flex portion of the gradient strength lift-assist band primarily deforms under the initial extension. However, once the elastic material layer of the flex portion has extended to the length of the inelastic material layer of the flex portion, the flex portion of the gradient strength lift-assist band no longer deforms.

[0061] The extension threshold 502 is the extent at which the flex portion of the gradient strength lift-assist band no longer deforms. Subsequent extension of the gradient strength lift-assist band begins to deform the elastic portion of the gradient strength lift-assist band comprising a stronger elastic strength. The precise position of the extension threshold 502 is dependent on the layer ratio of the inelastic material layer to the elastic material layer of the flex portion of the gradient strength lift-assist band. For example, a higher layer ratio means the elastic material layer of the flex portion may extend farther before the length of the elastic material layer equals the length of the inelastic material layer and the flex portion becomes inelastic. Thus, the extension threshold 502 may be at a greater extension.

[0062] As depicted in FIG. 5, the elastic portion elastic strength 506 comprises a steeper slope than the flex portion elastic strength 504. As such, more force is required to extend the gradient strength lift-assist band in the later stage region, however, the gradient strength lift-assist band also provides greater load assistance in the later stage region. Less force is required to extent the gradient strength lift-assist band in the initial tension region. Thus, a user may more easily stretch the gradient strength lift-assist band when initially picking up an object but may still be provided with adequate strength to lighten the burden of a heavy load.

[0063] Referring now to FIG. 6, an example method for manufacturing 600 a gradient strength lift-assist band (e.g., gradient strength lift-assist band 108) is provided. At block 602, a first band portion (e.g., elastic portion 112) comprising a first elastic material associated with a first elastic material strength is provided. As described herein, the first band portion may comprise an elastic material such as a rubber, spandex fiber, elastane, certain polymers, and other materials whichexhibit flexibility and resilience due to their molecular structure. In some embodiments, the elastic strength of the first band portion may be between 0.5 and 10 Newtons per millimeter.

[0064] At block 604, the method for manufacturing 600 a gradient strength lift-assist band comprises attaching a first layer (e.g., elastic material layer 204) comprising a second elastic material associated with a second elastic material strength to a second layer (e g., inelastic material layer 206) comprising an inelastic material, to produce a second band portion (e.g., flex portion 110). Further, the first elastic material strength is greater than the second elastic material strength. In addition, a second layer length (e.g., second layer length 302) associated with the second layer is greater than a first layer length (e.g., first layer length 304) associated with the first layer. As described herein, the gradient strength lift-assist band further includes a second band portion, or flex portion. The second band portion comprises a first layer comprising an elastic material and a second layer comprising an inelastic material. The elastic strength of the elastic material of the first layer is less than the elastic strength of the elastic portion of the gradient strength lift-assist band. In some embodiments, the elastic strength of the elastic material comprising the first layer of the flex portion may be between 0.5 and 10 Newtons per millimeter.

[0065] As further described herein, the length of the second layer of the flex portion is greater than the length of the first layer of the flex portion (e.g., elastic material layer 204) in a rest state. The layer ratio of the length of the second layer to the length of the first layer defines the overall elastic strength properties of the gradient strength lift-assist band. For example, the extension threshold may be defined based on the layer ratio.

[0066] The second layer of the second band portion may be attached to the first layer of the second band portion using any attaching mechanism. For example, the second layer of the second band portion may be sewn to the first layer of the second band portion. The second layer may be attached to the first layer in a plurality of sequential bounded elastic sections (e.g., bounded elastic section 202). For each bounded elastic section, the length of the second inelastic material layer is greater than the length of the first elastic material layer. The second layer may be attached to the first layer by compressing a portion of the second layer before sewing. Similarly, the first layer may be stretched to the length of the second layer and sewn together, thus, in an instance in which the first layer returns to a rest state, the second layer forms ruffles.

[0067] At block 606, the second band portion is attached to the first band portion. Any attaching mechanism may be used to attach the second band portion to the first band portion. Insome embodiments, the second band portion may be sewn to the first band portion such that three layers of material: the elastic material layer of the second band portion, the elastic portion, and the inelastic material layer of the second band portion are all attached.

[0068] Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Although the figures only show certain components of the apparatus and systems described herein, it is understood that various other components may be used in conjunction with the system. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, the steps in the method described above may not necessarily occur in the order depicted in the accompanying diagrams, and in some cases one or more of the steps depicted may occur substantially simultaneously, or additional steps may be involved. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0069] While various embodiments in accordance with the principles disclosed herein have been shown and described above, modifications thereof may be made by one skilled in the art without departing from the spirit and the teachings of the disclosure. The embodiments described herein are representative only and are not intended to be limiting. Many variations, combinations, and modifications are possible and are within the scope of the disclosure. The disclosed embodiments relate primarily to a lift-assist harness and corresponding strap, however, one skilled in the art may recognize that such principles may be applied to any strap requiring a gradient strength elastic band. Alternative embodiments that result from combining, integrating, and / or omitting features of the embodiment s) are also within the scope of the disclosure. Accordingly, the scope of protection is not limited by the description set out above.

[0070] Additionally, the section headings used herein are provided for consistency with the suggestions under 37 C.F.R. 1.77 or to otherwise provide organizational cues. These headings shall not limit or characterize the invention(s) set out in any claims that may issue from this disclosure.

[0071] Use of broader terms such as “comprises,” “includes,” and “having” should be understood to provide support for narrower terms such as “consisting of,” “consisting essentially of,” and “comprised substantially of’ Use of the terms “optionally,” “may,” “might,” “possibly,”and the like with respect to any element of an embodiment means that the element is not required, or alternatively, the element is required, both alternatives being within the scope of the embodiment(s). Also, references to examples are merely provided for illustrative purposes, and are not intended to be exclusive.

Claims

CLAIMS1. A lift-assist band comprising:a first band portion comprising a first elastic material associated with a first elastic material strength; anda second band portion comprising two layers:a first layer comprising a second elastic material associated with a second elastic material strength, wherein the first elastic material strength is greater than the second elastic material strength; anda second layer comprising an inelastic material, wherein in a rest state, a second layer length associated with the second layer is greater than a first layer length associated with the first layer.

2. The lift-assist band of claim 1,the first layer of the second band portion further comprising:a first layer first end; anda first layer second end; andthe second layer of the second band portion further comprising:a second layer first end; anda second layer second end;wherein the first layer first end is aligned with the second layer first end, and wherein the first layer second end is aligned with the second layer second end, such that a separation gap is defined between the first layer and the second layer.

3. The lift-assist band of either of claims 1 or 2, comprising a first band strength when deformed below an extension threshold, and a second band strength when deformed above the extension threshold.

4. The lift-assist band of claim 3, wherein the extension threshold is dependent on a layer ratio between the first layer length and the second layer length.

5. The lift-assist band of claim 4, wherein the layer ratio is greater than or equal to 0.5 and less than 1.0.

6. The lift-assist band of any one of claims 1 to 5, further comprising a plurality of sequential second band portions.

7. The lift-assist band of any one of claims 1 to 6, wherein the first elastic material strength is between 0.5 and 10 newtons per millimeter.

8. The lift-assist band of any one of claims 1 to 7, wherein the second elastic material strength is between 0.5 and 10 newtons per millimeter.

9. A lift-assist harness:a waist strap configured to attach around a waist of a user;a back portion comprising a first end and a second end, wherein the first end is attached to the waist strap; anda lift-assist band attached to the second end of the back portion, wherein the lift-assist band is positioned to track over a shoulder of the user and attach to a portion of an arm of the user, the lift-assist band comprising:a first band portion comprising a first elastic material associated with a first elastic material strength;a second band portion comprising two layers:a first layer comprising a second elastic material associated with a second elastic material strength, wherein the first elastic material strength is greater than the second elastic material strength; anda second layer comprising an inelastic material, wherein a second layer length associated with the second layer is greater than a first layer length associated with the first layer.

10. The lift-assist harness of claim 9,the first layer of the second band portion further comprising:a first layer first end; anda first layer second end; andthe second layer of the second band portion further comprising:a second layer first end; anda second layer second end;wherein the first layer first end is aligned with the second layer first end, and wherein the first layer second end is aligned with the second layer second end, such that a separation gap is defined between the first layer and the second layer.

11. The lift-assist harness of either of claims 9 or 10, wherein the lift-assist band comprises a first band strength when deformed below an extension threshold, and a second band strength when deformed above the extension threshold.

12. The lift-assist harness of claim 11, wherein the extension threshold is dependent on a layer ratio between the first layer length and the second layer length.

13. The lift-assist harness of claim 12, wherein the layer ratio is greater than or equal to 0.5 and less than 1.0.

14. The lift-assist harness of any one of claims 9 to 13, wherein the lift-assist band further comprises a plurality of sequential second band portions.

15. The lift-assist harness of any one of claims 9 to 14, wherein the first elastic material strength is between 0.9 and 1.1 newtons per millimeter.

16. The lift-assist harness of any one of claims 9 to 15, wherein the second elastic material strength is between 1.9 and 2.1newtons per millimeter.

17. A method of manufacturing a lift-assist band, the method comprising:providing a first band portion comprising a first elastic material associated with a first elastic material strength;attaching a first layer comprising a second elastic material associated with a second elastic material strength to a second layer comprising an inelastic material, to produce a second band portion, wherein the first elastic material strength is greater than the second elastic material strength; and wherein a second layer length associated with the second layer is greater than a first layer length associated with the first layer; andattaching the second band portion to the first band portion.

18. The method of manufacturing of claim 17, wherein the first layer of the second band portion further comprises:a first layer first end; anda first layer second end; andthe second layer of the second band portion further comprising:a second layer first end; anda second layer second end; andwherein attaching the first layer to the second layer comprises:aligning the first layer first end with the second layer first end;attaching the first layer first end with the second layer first end;aligning the first layer second end with the second layer second end; and attaching the first layer second end with the second layer second end, forming a separation gap between the first layer and the second layer.

19. The method of manufacturing of either of claims 17 or 18, wherein the lift-assist band comprises a first band strength when deformed below an extension threshold, and a second band strength when deformed above the extension threshold.

20. The method of manufacturing of claim 19, wherein the extension threshold is dependent on a layer ratio between the first layer length and the second layer length.

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