Obviousness

US Patent 9,414,635 (US'635) describes a biomechanics-aware helmet designed to mitigate not only direct impact forces but also rotational and shear forces, which are significant contributors to traumatic brain injury (TBI). The patent emphasizes that existing protective gear often fails to sufficiently dampen these rotational and shear forces, leading to neurological damage such as diffuse axonal injury (DAI) and coup-contrecoup injuries.

The core of the invention in US'635, as articulated in Claim 1, is a helmet featuring an outer shell layer and an inner shell layer. These layers are connected by a shear mechanism that allows the outer layer to slide relative to the inner layer. This shear mechanism includes a first energy transformer with an absorptive/dissipative material. A chin strap is attached to the inner shell layer to maintain its position on the wearer's head during rotational force impact, while the outer shell layer is allowed to slide.

A person having ordinary skill in the art (POSA) in helmet design, aware of the deficiencies of existing helmets in protecting against rotational and shear forces, as highlighted in US'635's own background, would have been motivated to combine prior art references to create a helmet with these improved protective qualities.

Obviousness Analysis under 35 U.S.C. § 103

The claims of US'635 would have been obvious to a POSA based on the combination of:

1. U.S. Pat. No. 7,076,811 (Puchalski)
2. U.S. Pat. No. 5,815,846 (Calonge)
3. General knowledge of helmet construction and components (e.g., chin straps, conforming liners).

Claim 1 Analysis

Claim 1: A helmet comprising: an outer shell layer; an inner shell layer connected to the outer shell layer through a shear mechanism allowing the outer shell layer to slide relative to the inner shell layer, wherein the shear mechanism includes a first energy transformer having a first absorptive/dissipative material, the inner shell layer configured to conform to a human head; a chin strap attached to the inner shell layer to maintain the position of the inner shell layer on the human head during rotational force impact while the outer shell layer is allowed to slide.

1. "A helmet comprising: an outer shell layer; an inner shell layer configured to conform to a human head; a chin strap attached to the inner shell layer..."

   • Helmets, outer shell layers, inner layers (or liners) configured to conform to a human head, and chin straps are fundamental and well-known components in the prior art for protective headgear. Puchalski and Calonge both disclose helmets. US'635 itself illustrates a conventional helmet (Helmet 201) with a shell layer 211, a lining layer 213 (configured to conform to a human head), and a chin strap 221. The patent further states that "Liners are provided beneath a hardened exterior shell to reduce violent deceleration of the head". The purpose of a chin strap is to secure the helmet, including its inner, head-conforming components, to the wearer's head.

2. "...connected to the outer shell layer through a shear mechanism allowing the outer shell layer to slide relative to the inner shell layer, wherein the shear mechanism includes a first energy transformer having a first absorptive/dissipative material..."

   • Puchalski discloses a helmet where the shell consists of "three (or more) discrete panels that are physically and firmly coupled together... but upon impact the panels move relative to one another... thereby permitting impact forces to be dissipated and/or redirected away from the cranium and brain within." This movement provides a "protective ‘crumple zone’ or ‘shear zone’". Puchalski thus teaches the critical concept of relative movement between helmet components (panels of a shell) to dissipate shear forces. A POSA, motivated by the need to address rotational and shear forces, would readily apply this principle to allow an outer shell layer to move relative to an inner shell layer.
   • Calonge describes an impact-resistant helmet assembly that includes "a fluid chamber in which a quantity of fluid is disposed. The fluid includes a generally viscous gel structured to provide some resistance against disbursement from an impacted region of the fluid chamber to non-impacted regions of the fluid chamber, thereby further enhance the impact distribution and dampening of the impact force provided by the helmet assembly". This clearly teaches the use of an "absorptive/dissipative material" (viscous gel) within a layer (fluid chamber) between helmet components for impact dampening and distribution. A viscous gel inherently allows for relative movement or "sliding" between the layers it separates, especially under shear forces, while dissipating energy.
   • Motivation to Combine: The motivation to combine Puchalski's concept of relative movement for shear dissipation with Calonge's use of a viscous gel as an absorptive/dissipative material is explicitly provided by US'635 itself. The patent identifies the "larger issue" as "preventing the tissue and neurological damage caused by rotational forces, shear forces, oscillations, and tension/compression forces" because "many pieces of protective gear do not sufficiently dampen, transform, dissipate, and/or distribute the rotational, tension, compression, and/or shear forces". A POSA, armed with this understanding, would be highly motivated to combine Puchalski's teaching of relative movement to create a "shear zone" with Calonge's viscous gel to effectively absorb and dissipate energy during such movement, thereby improving protection against rotational and shear forces. This combination directly results in a shear mechanism between helmet layers that allows sliding and incorporates an absorptive/dissipative material.

3. "...to maintain the position of the inner shell layer on the human head during rotational force impact while the outer shell layer is allowed to slide."

   • As noted, chin straps are conventional for securing a helmet to the wearer's head. When applied to a helmet designed with an inner layer that conforms to the head and an outer layer that slides, the chin strap's function remains unchanged: to keep the head-conforming inner layer in place. The phrase "while the outer shell layer is allowed to slide" merely describes the expected operational interaction of the combined components, not an inventive function of the chin strap itself.

Therefore, Claim 1 would have been obvious to a POSA motivated to improve helmet protection against rotational and shear forces by combining the teachings of Puchalski and Calonge with conventional helmet design elements.

Dependent Claims Analysis

• Claim 2 (shear mechanism is a shear layer): Calonge's fluid chamber containing viscous gel, acting as an impact dampening and distributing layer between material layers, inherently functions as a "shear layer". US'635 itself refers to "energy and impact transformer layers" that "flexibly connect the shell layers to absorb impact forces, rotational forces, shear forces, etc.". Making the shear mechanism a "shear layer" would be an obvious design choice for a POSA implementing such a system.
• Claim 3 (shear layer connected via first energy transformer with absorptive/dissipative material): This claim further defines the shear layer as the first energy transformer. As established, Calonge teaches a fluid chamber (layer) with viscous gel (absorptive/dissipative material) for dampening and distribution, which aligns directly with this structure.
• Claim 4 (second energy transformer): This claim introduces an additional energy transformer. US'635 explicitly describes and illustrates multiple shell systems (e.g., an outer, middle, and inner shell) with energy and impact transformative layers between them (FIG. 5 and FIG. 6) to address different types of forces. Puchalski also refers to "three (or more) discrete panels" in its shear zone. Given the objective of dissipating complex forces (rotational, shear, tension, compression), a POSA would find it obvious to add further layers of energy-absorbing material, similar to Calonge's gel or the other materials mentioned in US'635, to further enhance protection and dissipate residual forces.
• Claim 5 (gel as absorptive/dissipative material): Directly taught by Calonge, which uses a "viscous gel" for impact dampening. US'635 also lists "gels" as a material for its energy and impact transformer layers.
• Claim 6 (fluid as absorptive/dissipative material): Directly taught by Calonge, which uses a "fluid chamber". US'635 also lists "fluids" as a material for its energy and impact transformer layers.
• Claim 7 (electro-rheological element as absorptive/dissipative material): US'635 itself states that the "outer and inner energy and impact transformer layers may be constructed using gels, fluids, electro-rheological elements, magneto-rheological elements, etc.". It further details how electro-rheological elements, as "smart fluids," have electric field-dependent viscosity and can "react within milliseconds to reduce impact and shear forces between shells". Given Calonge's teaching of a viscous fluid, substituting it with a known "smart fluid" like an electro-rheological element for enhanced, active control of viscosity in response to impact would be an obvious improvement for a POSA.
• Claim 8 (lining layer connected to inner shell layer): A lining layer in a helmet for comfort, fit, and additional energy absorption is a standard, conventional feature. US'635's description of a conventional helmet (FIG. 2) includes a "lining layer 213" connected to the shell layer 211, noting it "may include lining materials, foam, and/or padding to absorb mechanical energy and enhance fit".

Claims 9-20, which relate to "Protective gear" or a "helmet" and use an "inner conforming layer" instead of an "inner shell layer," are similarly obvious for the reasons stated above. An "inner conforming layer" is functionally equivalent to an "inner shell layer configured to conform to a human head" and can be implemented by a lining, foam, or padding, as described in US'635 itself.

In conclusion, a POSA, motivated to improve helmet protection against the recognized problem of rotational and shear forces, would find it obvious to combine the shear-mitigating relative movement taught by Puchalski with the energy-absorbing viscous gel taught by Calonge, integrated into a conventional helmet structure with standard features like a chin strap and conforming inner layers. The dependent claims merely elaborate on these obvious design choices and material selections.