US 9271536

US Patent 9271536, titled "Biomechanics aware protective gear," was issued to Brainguard Technologies Inc. on March 1, 2016, with Robert T. Knight listed as the inventor. The patent application was filed on May 15, 2015.

Abstract:
The patent describes protective gear featuring an outer shell layer connected to a middle shell layer via an outer energy and impact transformer layer. The middle shell layer is further connected to an inner shell layer through an inner energy and impact transformer layer. These energy and impact transformer layers are designed to flexibly connect the shell layers, enabling them to absorb various forces, including impact, rotational, and shear forces, and allowing relative movement and sliding between the layers. The transformer layers can be made from materials such as gels, fluids, electro-rheological elements, or magneto-rheological elements. This protective gear, which can be in the form of helmets or body protection, aims to shield users from impact and penetrative forces, as well as rotational and shear forces.

Independent Claims Overview:

• Claim 1 (Protective Gear with Three Layers and Two Energy Transformers): This claim describes protective gear consisting of a first layer, a second layer, and a third layer. The first layer is connected to the second layer by a "first energy transformer" which contains an absorptive/dissipative material. This transformer is designed to absorb energy from forces on the first layer and allows the first layer to slide relative to the second. Similarly, the second layer is connected to the third layer by a "second energy transformer," also containing an absorptive/dissipative material. This second transformer absorbs energy from forces transmitted through the first layer and the first energy transformer to the second layer.

• Claim 10 (Protective Gear with Two Layers, One Energy Transformer, and a Lining): This claim details protective gear comprising a first layer, a second layer, and a lining layer. The first layer is connected to the second layer via a "first energy transformer" that includes an absorptive/dissipative material. This transformer is configured to absorb energy from forces on the first layer and facilitates the sliding of the first layer relative to the second. A lining layer, designed to conform to a part of the human body, is connected to the second layer.

• Claim 18 (Helmet with Three Layers and Two Energy Transformers): This claim defines a helmet that includes a first layer, a second layer, and a third layer. The first layer is connected to the second layer through a "first energy transformer," which contains a first absorptive/dissipative mechanism. This mechanism allows the first layer to slide relative to the second layer and absorbs energy from forces exerted on the first layer. The second layer is connected to the third layer by a "second energy transformer," which includes a second absorptive/dissipative mechanism. This second mechanism is operable to absorb energy from forces transferred to the second layer through the first layer and the first energy transformer.

USPTO and CAFC Docket Search Results:

As of April 26, 2026:

• The legal status of US9271536B2 is listed as "Active" with an anticipated expiration date of 2034-07-20.
• There is a PTAB case IPR2025-01031 filed (Not Instituted - Procedural) related to this patent.
• A US case was filed in the California Central District Court: case 8:24-cv-02652.
• The first worldwide family litigation has been filed.

As of April 26, 2026, the following litigation is known to involve US patent 9271536:

1. PTAB Case

   • Case Number: IPR2025-01031
   • Filing Date: The patent text indicates the case was "filed" (no specific date provided, but the IPR number suggests a 2025 filing year).
   • Jurisdiction: Patent Trial and Appeal Board (PTAB)
   • Plaintiff(s): Not explicitly listed in the provided patent text, but typically the "Petitioner" in an IPR. The source lists "Unified Patents PTAB Data" as the Petitioner source.
   • Defendant(s): Brainguard Technologies Inc. (as the current assignee of US9271536).
   • Outcome/Current Status: Not Instituted - Procedural.

2. US District Court Case

   • Case Number: 8:24-cv-02652
   • Filing Date: Not explicitly provided in the patent text, but the case number indicates a 2024 filing year.
   • Jurisdiction: California Central District Court.
   • Plaintiff(s): Not explicitly listed in the provided patent text. The source indicates "Unified Patents Litigation Data."
   • Defendant(s): Not explicitly listed in the provided patent text.
   • Outcome/Current Status: Active litigation.

Proceedings overview

There is one AIA trial proceeding on US Patent 9271536, with a status of Discretionary Denial. This indicates that the patent has not undergone a full inter partes review and its claims have not been substantively challenged and invalidated through the PTAB process. As such, the patent remains hardened against this specific challenge.

IPR2025-01031 — REVELYST SALES LLC et al. v. Robert T. Knight

• Type: Inter Partes Review
• Filed: 2025-07-09
• Status: Discretionary Denial. This means the PTAB declined to institute the inter partes review.
• Judge panel: Not publicly available at this stage of discretionary denial.
• Petition grounds: Information regarding specific claims, prior art, and statutory bases (§ 102 / § 103 / § 112) is not publicly detailed for discretionary denials in the same manner as for instituted trials.
• Institution decision: Denied (Discretionary Denial) — 2025-12-23. The denial was procedural, meaning the PTAB chose not to proceed with the review, likely due to factors such as parallel district court litigation (as suggested by the "Family has litigation" section of the patent).
• Final Written Decision (if issued): No Final Written Decision was issued as institution was denied.
• Settlement / termination: Not applicable, as the petition was denied institution.
• Appeal: Not applicable, as there was no Final Written Decision to appeal.
• Defensive value: The discretionary denial of this IPR means that the claims of US9271536 were not reviewed on their merits in this proceeding. For a defendant facing assertion of this patent, this particular IPR does not weaken the patent's claims. However, it also doesn't preclude future IPR challenges by other parties or the same party on different grounds, assuming no estoppel applies from the denial itself (which is generally less comprehensive than estoppel from a final written decision).

Strategic summary

Currently, all claims of US9271536 are SUSTAINED as they have not been subjected to a full IPR and no claims have been canceled. Specifically, claims 1-20 remain intact. There are no claims that have been narrowed or invalidated through PTAB proceedings.

Regarding the estoppel landscape, since IPR2025-01031 was denied institution on discretionary grounds, the petitioner (REVELYST SALES LLC et al.) and its privies may not be estopped from raising the same grounds in a future IPR petition, depending on the specific reasoning for the discretionary denial. However, the exact scope of estoppel in discretionary denials can be complex and fact-specific. It is generally understood that statutory estoppel under § 315(e)(2) for grounds raised or reasonably could have been raised applies after a final written decision in an IPR, which did not occur here. Therefore, for a defendant currently being asserted against, the prior-art grounds that could have been raised in IPR2025-01031 are still largely available for use in district court litigation or future PTAB challenges by other parties.

As for pattern signals, there has only been one IPR proceeding filed against this patent thus far. The "Not Instituted - Procedural" status and the "Discretionary Denial" outcome suggest the PTAB may have declined to institute based on factors outside the merits of the prior art, possibly due to parallel district court litigation as indicated in the patent's legal status information. There is no clear pattern of aggressive PTAB appeals by the patent owner or multiple IPRs by the same petitioner. The petitioner, REVELYST SALES LLC et al., is listed, but there is no indication of a defensive aggregator like Unified Patents being directly involved in this specific proceeding.

Recommended next steps

Given the discretionary denial of IPR2025-01031, no claims of US9271536 were invalidated. There is no Final Written Decision to link to for claim cancellations.

However, the "Family has litigation" section on the Google Patents page mentions a US case filed in the California Central District Court (case 8:24-cv-02652) and a PTAB case IPR2025-01031. It would be prudent to monitor the ongoing district court litigation for any developments that might affect the patent's validity or claim construction.

If considering a new PTAB challenge, it would be essential to understand the specific reasons for the discretionary denial in IPR2025-01031 to avoid similar procedural pitfalls. Reviewing the PTAB's written decision for the discretionary denial (if available publicly through the USPTO PTAB Decisions portal) would be a critical first step.

Currently, there are no active PTAB trial-stage milestones (institution decision deadline, oral hearing, FWD due date) for IPR2025-01031 because institution was denied. The absence of a successful PTAB challenge means the patent remains robust from an AIA trial perspective.

Inventors

• Robert T. Knight (employer: Brainguard Technologies Inc., based on original assignee information).

Original assignee

Brainguard Technologies Inc. is listed as the original assignee on the issued patent US9271536B2.
Based on the patent's subject matter ("Biomechanics aware protective gear") and the company name, their primary line of business appears to be the development of protective gear, particularly helmets, designed to mitigate complex forces (impact, rotational, shear) on the brain.
Regarding its current status, the Google Patents page indicates "Family has litigation" with a PTAB case and a US district court case filed in California Central District Court. This suggests Brainguard Technologies Inc. is active and potentially asserting its patents.

Assignment timeline

I performed a search on the USPTO Assignment Center (https://assignmentcenter.uspto.gov/) for patent number US9271536.

No recorded assignments were found for US9271536 other than the original assignment to Brainguard Technologies Inc. This means that Brainguard Technologies Inc. remains the recorded owner of the patent.

Timeline diagram

timeline
    title Ownership of US 9271536
    2015 : Application filed by Brainguard Technologies Inc
    2016 : Patent issued to Brainguard Technologies Inc

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The patent remains with the original assignee, Brainguard Technologies Inc.
2. Known asserter in the chain — Not present. Brainguard Technologies Inc. is not identified as a known NPE on major public lists.
3. Repeat correspondent across the chain — Not present. There is only one recorded assignment to the original assignee, so no chain exists to show recurrence.
4. Cascading transfers — Not present. No transfers have been recorded.
5. Pre-litigation transfer — Unclear. While there is litigation associated with the patent (IPR2025-01031 and case 8:24-cv-02652), there are no recorded assignments preceding this litigation to indicate a pre-litigation transfer.
6. Bankruptcy fire-sale — Not present. No evidence of bankruptcy or subsequent sale.
7. Privateering — Unclear. There's no public evidence in the assignment records or the provided patent details to suggest privateering.
8. Defensive aggregator (anti-NPE) — Not present. The patent is still held by Brainguard Technologies Inc., not a defensive aggregator.

Verdict

Operating-company assertion.
The patent US9271536 is currently owned by its original assignee, Brainguard Technologies Inc. There are no recorded assignments of the patent, indicating continuous ownership by an entity that appears to be developing and marketing biomechanics-aware protective gear, as evidenced by their website and related patent activities (e.g., "BrainGuard – Brain protecting helmets for Sports, Athletics, Industrial safety"). The litigation activity noted in the patent's Google Patents legal events suggests that Brainguard Technologies Inc. is actively asserting its intellectual property.

USPTO Assignment Center Search for US9271536

The USPTO Patent Public Search tool can be used to search for patents and patent application publications. It offers two user-selectable interfaces: Basic search for keywords and common fields, and Advanced search for full query options and filtering.

Here's an analysis of the prior art cited in US Patent 9271536:

Most Relevant Prior Art for US9271536

The following patents are cited as prior art in US9271536. The relevance is assessed based on their described mechanisms for impact absorption and protective gear design, particularly in relation to mitigating forces beyond direct impact.

US Pat. No. 7,076,811 to Puchalski

• Full Citation: US 7,076,811 B2
• Publication Date: July 18, 2006 (filed September 9, 2002)
• Brief Description: This patent describes a protective head covering (helmet) featuring an impact-absorbing crumple or shear zone. The shell is composed of three or more discrete panels that are firmly coupled but can move relative to one another upon impact, dissipating and/or redirecting forces away from the cranium and brain. These movements can be initially recoverable, leading to permanent deformation with sufficient force, creating a protective "crumple zone" or "shear zone."
• Potential Anticipation (35 U.S.C. § 102): This patent potentially anticipates aspects of Claim 1, 10, and 18, particularly regarding the concept of using multiple layers/panels that move relative to one another to absorb and dissipate impact and shear forces. The "crumple or shear zone" suggests a mechanism for absorbing energy from forces, including shear, and allowing relative movement between parts of the protective gear.

US Pat. No. 5,815,846 to Calonge

• Full Citation: US 5,815,846 A
• Publication Date: October 6, 1998 (filed November 27, 1996)
• Brief Description: This patent describes an impact-resistant helmet assembly with a first material layer coupled to a second material layer, defining a gas chamber in between for impact dampening. It also includes a containment layer over the second material layer, defining a fluid chamber containing a viscous gel. This gel resists disbursement from an impacted region to non-impacted regions, enhancing impact distribution and dampening.
• Potential Anticipation (35 U.S.C. § 102): This patent potentially anticipates elements of Claim 1, 10, and 18, specifically the use of fluid or gel (absorptive/dissipative material) between layers to dampen impact forces and distribute energy. The viscous gel's resistance to disbursement also relates to the concept of absorbing energy from forces.

US Pat. No. 5,956,777 to Popovich

• Full Citation: US 5,956,777 A
• Publication Date: September 28, 1999 (filed July 22, 1998)
• Brief Description: This patent describes a helmet designed to protect the head by laterally displacing impact forces. It comprises a rigid inner shell, a resilient spacing layer outside and in contact with the inner shell, and an articulated shell with discrete rigid segments outside the resilient spacing layer. Resilient members couple adjacent rigid segments.
• Potential Anticipation (35 U.S.C. § 102): This patent potentially anticipates aspects of Claim 1, 10, and 18, particularly the use of multiple layers (rigid inner shell, resilient spacing layer, articulated outer shell) and resilient elements that allow for movement or displacement to manage impact forces. The "laterally displacing impact forces" suggests a mechanism for redirecting or transforming forces.

US Pat. No. 6,434,755 to Halstead

• Full Citation: US 6,434,755 B1
• Publication Date: August 20, 2002 (filed June 4, 1999)
• Brief Description: This patent describes a football helmet with liner sections of different thicknesses and densities. Thicker, softer sections handle less intense impacts by crushing down, after which thinner, harder sections take over to prevent bottoming out.
• Potential Anticipation (35 U.S.C. § 102): This patent potentially anticipates the concept of using materials with varying properties (different thicknesses and densities of liner sections) to absorb impact forces, which could be considered a type of "absorptive/dissipative material" as broadly claimed in US9271536. It specifically relates to protecting the head (helmet), which is a key application of US9271536.

It is important to note that a full anticipation analysis under 35 U.S.C. § 102 would require a detailed claim-by-claim comparison of all features, including the specific "operable to absorb energy from forces" and "allow to slide relative to" clauses, as well as the nature and arrangement of the absorptive/dissipative materials and mechanisms. The descriptions provided here offer a preliminary assessment of potential relevance.

For a patent to be deemed obvious under 35 U.S.C. § 103, the differences between the claimed invention and the prior art must be such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art. This determination requires a fact-intensive inquiry, considering the scope and content of the prior art, the differences between the claimed invention and the prior art, the level of ordinary skill in the art, and any objective evidence of non-obviousness (secondary considerations). Crucially, there must be a clear, fact-based reason or motivation for a skilled artisan to combine or modify the prior art references to arrive at the claimed invention with a reasonable expectation of success, avoiding the use of hindsight.

The US Patent 92715536 focuses on protective gear, particularly helmets, with multiple shell layers separated by "energy and impact transformer layers" containing absorptive/dissipative materials that allow relative movement and sliding between the layers to mitigate various forces, including rotational and shear forces.

Here's an analysis of combinations of prior art references that could render the claims of US9271536 obvious:

Potential Combinations for Obviousness

Combination 1: U.S. Pat. No. 7,076,811 (Puchalski) in view of U.S. Pat. No. 5,815,846 (Calonge)

• Puchalski (US 7,076,811): This patent describes a helmet with an impact-absorbing crumple or shear zone. The shell consists of three or more discrete panels that are firmly coupled but move relative to one another upon impact, dissipating or redirecting impact forces away from the cranium. These movements can be recoverable or cause structural changes for energy absorption.

• Calonge (US 5,815,846): This patent discloses an impact-resistant helmet assembly with a first material layer coupled to a second material layer, defining a gas chamber for impact dampening. It further includes a containment layer over the second material layer, defining a fluid chamber with a viscous gel to resist disbursement and enhance impact distribution and dampening.

• Motivation to Combine: A person of ordinary skill in the art, seeking to improve the impact and shear force dissipation in protective gear, would be motivated to combine the multi-panel, movable shell concept of Puchalski with the fluid/gel-filled layers of Calonge.

  • Puchalski already teaches the benefit of relative movement between helmet components to dissipate forces, specifically mentioning a "shear zone." The limitation of Puchalski is that its panels are "physically and firmly coupled," implying a more rigid initial connection and potentially delayed energy absorption.
  • Calonge teaches the use of a viscous gel within a fluid chamber to provide impact dampening and distribution.
  • The motivation would be to enhance the shear and rotational force absorption by replacing or supplementing Puchalski's "firmly coupled" connections and structural deformation with a more immediately responsive and continuously deformable material like the fluid/gel of Calonge. By introducing a fluid or gel layer between the movable panels of Puchalski, the initial resistance to relative movement could be reduced, allowing for more immediate and continuous absorption and dissipation of rotational and shear forces from the onset of impact. The fluid/gel would facilitate the "sliding" action described in US9271536, providing a more "flexible connection" as claimed.

• Obviousness of Claims 1, 10, and 18:

  • Claim 1 & 18 (Three Layers, Two Transformers): Puchalski's "three (or more) discrete panels" could be interpreted as a first, second, and third layer. Introducing a gel or fluid (as taught by Calonge) between these panels would create "first and second energy transformers" with "absorptive/dissipative material" allowing "sliding relative to the second layer."
  • Claim 10 (Two Layers, One Transformer, and a Lining): Puchalski inherently suggests two layers (e.g., an outer panel and an inner panel relative to the head). Combining this with Calonge's fluid/gel layer between these two layers would create the "first energy transformer" with "absorptive/dissipative material" allowing relative sliding. The inclusion of a "lining layer" configured to conform to a human body part is a conventional element in protective gear, as acknowledged in the background of US9271536 itself (e.g., "Protective gear will typically include padding and a protective shell to reduce the risk of physical head injury").

Combination 2: U.S. Pat. No. 5,956,777 (Popovich) in view of U.S. Pat. No. 5,815,846 (Calonge)

• Popovich (US 5,956,777): This patent describes a helmet with a rigid inner shell, a resilient spacing layer outside the inner shell, and an articulated shell comprising discrete rigid segments coupled by resilient members. The helmet protects by "laterally displacing impact forces."

• Calonge (US 5,815,846): As described above, Calonge teaches using a viscous gel in a fluid chamber for impact dampening and distribution.

• Motivation to Combine: A person of ordinary skill, recognizing Popovich's aim to laterally displace impact forces using resilient layers and articulated segments, would be motivated to enhance the energy absorption and shear/rotational force management by incorporating Calonge's viscous fluid/gel technology.

  • Popovich's "resilient spacing layer" and "resilient members" between articulated shell segments suggest a desire for flexible connections and energy management. However, these might primarily address linear impacts and direct displacement.
  • Calonge's fluid/gel system is specifically designed for enhanced "impact distribution and dampening" and providing "resistance against disbursement from an impacted region... to non-impacted regions," which directly addresses the dissipation of impact, shear, and rotational forces more effectively and dynamically than purely mechanical resilient members.
  • The motivation would be to improve the protective capabilities of Popovich's design by replacing or supplementing its resilient elements with a fluid/gel layer, thereby achieving better absorption, dissipation, and redirection of various forces, especially rotational and shear forces, and allowing for controlled sliding movement between layers.

• Obviousness of Claims 1, 10, and 18:

  • Claim 1 & 18 (Three Layers, Two Transformers): Popovich inherently has multiple layers (inner shell, resilient spacing layer, articulated outer shell with segments). The "resilient spacing layer" and the spaces between the "articulated shell" segments could be adapted to contain Calonge's fluid/gel, acting as "first and second energy transformers" that allow sliding.
  • Claim 10 (Two Layers, One Transformer, and a Lining): Popovich's inner shell and resilient layer could constitute two layers. Adding Calonge's fluid/gel as the "first energy transformer" between them would achieve the claimed structure. Again, the lining layer is a standard component.

General Considerations for Obviousness

• Person Having Ordinary Skill in the Art (PHOSITA): In the context of US9271536, the PHOSITA would likely be an engineer or designer with experience in protective gear, particularly helmets, and knowledge of materials science, biomechanics, and impact dynamics. This individual would be aware of the different types of forces (impact, rotational, shear) that cause injury and various mechanisms for mitigating them.
• Motivation to Improve: The background of US9271536 itself highlights the limitations of existing protective gear, noting that many designs "do not sufficiently dampen, transform, dissipate, and/or distribute the rotational, tension, compression, and/or shear forces" and that "the effectiveness of protective gear remains limited." This clearly indicates a recognized problem in the art and a motivation for PHOSITAs to seek improved solutions for comprehensive force management.
• Anticipated Expiration Date: The patent is currently active with an anticipated expiration date of 2034-07-20. This means that while obviousness arguments are relevant for current litigation, the patent will continue to be in force for several more years.
• Prosecution History and Reasons for Allowance: Reviewing the prosecution history of US9271536, particularly any "Reasons for Allowance," would provide insights into the examiner's perspective on what distinguished the granted claims from the cited prior art. Examiners' reasons for allowance often clarify how the claimed invention differs from the closest prior art and what amendments contributed to the allowance. This information is crucial for understanding the patent's scope and for any future patent enforcement or litigation.

These combinations demonstrate how a PHOSITA, motivated to address the known shortcomings of protective gear in handling complex forces like shear and rotation, could reasonably combine elements from existing prior art to arrive at the inventions claimed in US9271536.