Obviousness

A Person Having Ordinary Skill in the Art (PHOSITA) would have found the claimed invention of US Patent 11986946 obvious in light of a combination of prior art references, specifically US Patent 5,518,139 (Waterloo) and US Patent 6,082,539 (Lee).

Obviousness Analysis

Primary Reference: US Patent 5,518,139 to Waterloo Industries, Inc. (Waterloo)

Waterloo describes a "Portable storage assembly" designed for stacking and interlocking containers. Its abstract explicitly states: "An automatic locking mechanism is provided for automatically locking the upper container to the lower container when the upper container is placed on the lower container. A release mechanism is provided for releasing the locking mechanism to permit separation of the upper container from the lower container."

Waterloo thus teaches several key elements of US11986946's independent claims:

• Storage boxes (upper and lower containers).
• First and second connection parts (implicitly, the interlocking features on the containers).
• An automatic locking mechanism that includes a locking buckle (latch) movable with respect to a mounting body, biased by a first resilient member to automatically engage a mating part on another storage box upon alignment. This mechanism inherently uses a resilient member to drive the locking component into engagement.
• A locking part (the release mechanism) that allows for manual movement of the locking buckle to an unlocked state.

The primary features missing from Waterloo, relative to US11986946, pertain to the "stop part" that enables a "hold unlocked" state without continuous manual intervention. The background section of US11986946 highlights this as a deficiency in existing technology, noting the need to "deliberately keep the locking part in the unlocked state by hand, freeing the user's hands."

Secondary Reference: US Patent 6,082,539 to Lee (Lee)

Lee describes a "Locking device of a tool box," a highly analogous art to storage boxes. Lee's abstract discloses a locking device that includes a latch (hook) and a spring biasing the hook to engage. Crucially, Lee further teaches "a safety lock button engaged with the hook for maintaining the hook in the release position."

This "safety lock button" in Lee directly provides the function of the "stop part" in US11986946. It is a mechanism that projects outward (engages) to prevent the primary locking mechanism (hook/latch) from automatically engaging, thereby keeping the device in a "release" or "unlocked" state. The nature of a "safety lock button" implies it is retractable; it extends to hold the unlocked state and is compressed or disengaged when the primary latch is permitted to move into its locked position.

Motivation to Combine

A PHOSITA, seeking to improve the convenience and user experience of interlocking storage boxes, such as those taught by Waterloo, would be motivated to address the problem of requiring continuous manual effort to keep the boxes in an unlocked state. The solution provided by Lee—a "safety lock button" that maintains a latch in a release position—is a well-known and conventional approach in the field of mechanical locking devices, especially for containers like toolboxes.

It would be an obvious design choice for a PHOSITA to integrate Lee's "safety lock button" mechanism into Waterloo's automatic locking storage box assembly. This combination would directly achieve the "automatic locking, keeping unlocking and automatic reset functions" touted as beneficial effects in US11986946. By adapting Lee's safety lock button to interact with the locking buckle of Waterloo's system, the PHOSITA would enable users to keep the storage boxes in a "hold unlocked" state, preventing automatic engagement of the locking buckle until the stop part is intentionally disengaged. Both references operate within the realm of secure and convenient container handling, making the combination logical and predictable for a PHOSITA.

Application to Claims:

• Claim 1: The combination of Waterloo and Lee clearly discloses all elements. Waterloo provides the storage box, the first and second connection parts, the mounting body, the locking buckle movable with respect to the mounting body, the first resilient member for automatic locking, the mating part, and the manual release mechanism. Lee provides the "stop part" (safety lock button) which projects outward to prevent automatic locking (maintaining a "hold unlocked" state) and is retractable (extended when holding unlocked, compressed when locked).
• Claim 11: This claim further specifies the stop part being biased outward from a slot by a second resilient member and moving perpendicular to the sliding path of the locking part. It is a common and conventional engineering practice to employ a spring (second resilient member) to bias a safety or stop button into its engaged position. Furthermore, the specific movement of such a stop part (e.g., perpendicular to a horizontally sliding latch, as suggested by "sliding latch for horizontal movement" in Claim 7 of US11986946) to block or clear the locking path is a standard mechanical design choice readily apparent to a PHOSITA.
• Claim 15: This claim describes the locking buckle as being biased outward to a locked state, which is a directional variation of the automatic locking principle (as opposed to "inward" in Claim 1), and thus an obvious design choice for a PHOSITA. The detailed description of the stop part, including its holding slot and second resilient member, with its extended position corresponding to the unlocked state (buckle retracted) and retracted position corresponding to the locked state (buckle extended), is consistent with the functional and structural adaptation of Lee's safety lock button into a system like Waterloo's. Housing such a stop part in a slot and biasing it with a resilient member are conventional mechanical design techniques.

Therefore, the combination of Waterloo (US5518139A) and Lee (US6082539A) would have rendered the independent claims of US11986946 obvious to a PHOSITA, as it provides a clear teaching and motivation for all claimed features.