Obviousness

To assess the obviousness of US Patent 11964175 under 35 U.S.C. § 103, we must identify combinations of prior art references that would render the claims obvious and explain the motivation a person having ordinary skill in the art (POSITA) would have to combine them. The primary objective of the claimed invention is to provide a bridge rope assembly for a harness, particularly one that safely utilizes ultra-high molecular weight polyethylene (UHMWPE) despite its low coefficient of friction.

Claim 1 Breakdown:
Claim 1 describes a bridge rope assembly for coupling a tree rope to a harness. Key features include:

1. A main body rope with a splice forming an eye loop, which engages a first bridge loop of a harness.
2. Crucially, a "first portion" of the main body rope, including its first end, extends through a "second portion" (including the second end) such that the first end is positioned within the second portion adjacent to the second end. This describes a very long internal bury of one end of the rope.
3. A friction hitch, comprising a closed loop, positioned on the main body between the second end and the eye loop, configured to engage a second bridge loop of the harness.

Dependent claims further specify dimensions, the use of a stop knot, a securing member at the rope ends, and the material (UHMWPE) for both the main body and the friction hitch.

Identified Prior Art Combinations and Obviousness Analysis:

A POSITA in the field of safety equipment, particularly for tree-stand hunting or climbing, would possess knowledge of harness systems, rope materials, and splicing techniques.

Combination 1: Bridge Rope Assembly with UHMWPE and Long Buried Splices

• Reference 1: US11351405B2 (Tethrd LLC) – "Safety harness bridge rope engagement system". This patent, having a priority date of June 19, 2019, predates US11964175's earliest priority date of January 7, 2020. It discloses a bridge rope engagement system for a harness, encompassing the general concept of connecting a harness to a tree rope via a bridge rope, likely featuring an eye loop for engagement and an adjustable connection point. Thus, it provides the foundational "bridge rope assembly configured to couple together a tree rope to a first bridge loop and a second bridge loop on a harness" and the main body having an eye loop configured to engage the first bridge loop.

• General Knowledge/Motivation for Material Choice: The detailed description of US11964175 explicitly states that UHMWPE (e.g., Amsteel) is a material "characteristically includ[ing] extremely long chains of polyethylene having 100,000 to 250,000 monomer units per molecule" and that it is "extremely strong" and "available from numerous suppliers." The patent itself recognizes its superior strength-to-weight ratio. A POSITA would be continuously motivated to improve the performance of safety equipment by seeking lighter and stronger materials. Therefore, the selection of UHMWPE for a bridge rope assembly would be an obvious choice to enhance strength and reduce weight.

• Reference 2: US4036101A (The Burnett Company, Ltd.), "Double hollow braided rope assembly and method" (priority date 1975-12-01).

• Reference 3: US4099750A (Mcgrew James D), "Method of forming eye splice in double braided line" (priority date 1977-09-02).

• Reference 4: US5699657A (Paulson; William Thomas), "Braided line splices and methods of splicing to form same" (priority date 1996-05-23).
  These references collectively teach various methods of forming eye splices and other buried splices in braided ropes, demonstrating the principle of burying one rope portion within another to create secure connections. A fundamental principle in rope splicing, recognized by a POSITA, is that a longer bury length increases frictional engagement and thus the security and strength of the splice, particularly for ropes with low coefficients of friction.

• Motivation to Combine References 1, General Knowledge (UHMWPE), and References 2-4 for Claim 1:
  A POSITA, starting with a bridge rope assembly as generally taught by US11351405B2, and motivated to improve its strength and reduce weight, would naturally consider using UHMWPE for the rope material (as it's a known high-performance material). Upon selecting UHMWPE, the POSITA would immediately confront the material's known low coefficient of friction, which is explicitly mentioned in US11964175 as a challenge that can prevent ropes from retaining a closed loop formation under stress. To overcome this, the POSITA would refer to well-known splicing techniques (e.g., US4036101A, US4099750A, US5699657A) and apply the established principle that a longer bury enhances friction and security. It would be an obvious design choice to maximize this effect for a safety-critical application by extending the first portion of the main body rope through the second portion, such that the first end is positioned within the second portion, ideally adjacent to the second end. This creates a substantial double layer of rope, significantly increasing friction and preventing slippage, directly addressing the low-friction characteristic of UHMWPE. The patent itself highlights that "the extension of the first portion 32 through the second portion 34 further resists the movement of the first portion 32 outwardly away from the second portion 34 while increasing a thickness of main body 12 such that it may be gripped easier."

Combination 2: Friction Hitch on the Main Body

• Reference 1 (from Combination 1): US11351405B2 provides the context of a bridge rope assembly for a harness.
• General Knowledge/The Disclosure of US11964175: The disclosure for US11964175 states, "The friction hitch 42 is formed in a conventional manner and is configured to engage a second bridge loop 44 of the harness 26." It further specifies that "The closed loop 46 is formed into the friction hitch using what is commonly referred to as a Prusik knot." Prusik knots and other friction hitches formed from a closed loop of rope are conventional and widely known in climbing, arborist, and rigging applications for creating adjustable connections on a main rope.
• Motivation to Combine: A POSITA designing a bridge rope assembly (e.g., as in US11351405B2) would readily recognize the desirability of an adjustable connection to a second bridge loop of the harness. The use of a conventional friction hitch, such as a Prusik knot formed from a closed loop of rope, for this purpose is a standard and obvious solution to provide adjustability. Positioning it on the main body between the existing eye loop and the second end of the main body is a logical arrangement for such a system.

Obviousness of Dependent Claims:

• Claims 2, 3, 7, 8, 9, 13, 14 (Dimensions): The specific lengths (e.g., rope length, eye loop to second end distance, single rope length for closed loop, closed loop circumference, distance between first and second ends being less than 2.0 inches) are design choices that a POSITA would determine through routine experimentation and optimization based on factors such as user height, harness design, ergonomic considerations, and safety standards, all of which are within the purview of routine engineering for such equipment. The "less than 2.0 inches" adjacent spacing for the main body's ends is a direct consequence of maximizing the bury length to address UHMWPE's low friction, as motivated above.
• Claim 4 (Stop Knot) and Claim 5 (Securing Member): The patent itself notes that a stop knot "may comprise, for example, a double fisherman's knot" and that a "securing member may comprise a heat shrink wrap sleeve." Both double fisherman's knots and heat shrink wrap sleeves are conventional elements in rope work. Stop knots prevent slippage or mark an end point, while securing members protect rope ends from fraying and further secure buried tags.
  • Motivation to Combine: A POSITA, having constructed a long-buried splice in a UHMWPE rope for a safety application, would be motivated to further enhance the security and durability of the rope assembly. Employing conventional stop knots and securing members (like heat shrink wrap) at the ends of the buried sections would be an obvious choice to prevent fraying, further secure the splice, and ensure long-term reliability in a critical safety device.
• Claim 6 (Closed loop from a single rope): As discussed, a friction hitch like a Prusik knot is conventionally formed from a single rope tied into a continuous closed loop. This is an inherent characteristic of such knots and would be obvious to a POSITA.
• Claims 10, 11 (UHMWPE for main body and friction hitch): As established above, the motivation to use UHMWPE for its strength and light weight is clear. Once UHMWPE is chosen for the main body, extending its use to the friction hitch rope would be an obvious choice for consistency and to realize similar benefits in that component. The challenges of its low friction and the need for long splices would apply equally to the friction hitch's closed loop, as noted in the patent's description of the closed loop's splice.

Conclusion:
The claims of US Patent 11964175 would have been obvious to a person having ordinary skill in the art at the time of the invention. The combination of a known bridge rope assembly (e.g., US11351405B2) with the known high-strength, low-friction material UHMWPE (general knowledge, acknowledged by the patent) and conventional long-bury splicing techniques (e.g., US4036101A, US4099750A, US5699657A) would be motivated by a desire for a lighter, stronger, and safer harness system. Similarly, the incorporation of a conventional friction hitch (as described in the patent's own disclosure as "conventional") for adjustability, along with other conventional safety features like stop knots and securing members (also described as conventional in the patent), would be obvious improvements or design choices within the ordinary skill in the art. The specific dimensions would be routine engineering for such a product.