Prior art

Most Relevant Prior Art for US Patent 9403550

The following prior art references are identified as most relevant to US Patent 9403550, "Seat attachment for a stroller," based on their disclosure of convertible or multi-seat stroller configurations with detachable seating. The analysis focuses on potential anticipation under 35 U.S.C. § 102, considering if each element of US9403550's independent claims (Claims 1 and 7) is found in a single prior art reference. The key differentiating features in US9403550's claims are the provision of a first seat and a second seat attachment supporting a second seat, where the second seat is positioned at a "second vertical position substantially below the first vertical position" and "closer to the front wheels," using distinct left and right seat support elements releasably connected to the stroller frame.

Here are the most relevant prior art patents:

1. US7481439B2 - Modular stroller

• Full Citation: US7481439B2
• Publication/Filing Date: Publication: 2009-01-27; Priority: 2003-09-02 (Earlier than US9403550's priority date of 2008-12-04)
• Brief Description: This patent describes a modular stroller apparatus for one or more children, configurable into single, double, and triple passenger configurations with various orientations. It includes a frame assembly and at least one seat assembly (and optionally car seat adapters) configured for removable attachment to the frame. The stroller can assume at least two distinct configurations offering different passenger capacities or arrangements.
• Potential Anticipation under 35 U.S.C. § 102: US7481439B2 strongly anticipates Claims 1 and 7 of US9403550. Its disclosure of "double and triple passenger configurations" with "removable attachment" of seat assemblies directly addresses the core inventive concept. Figures within US7481439B2 (e.g., FIG. 1, FIG. 15) illustrate a front seat positioned both lower than and forward of a rear seat, thereby potentially disclosing the "second vertical position substantially below the first vertical position" and "closer to the front wheels" for the second seat as claimed in US9403550. While the specific "left and right seat support elements" with distinct connector portions and seat connectors are a detailed aspect, the attachment mechanisms described in US7481439B2 would inherently provide left and right support points to securely mount the front seat to the frame.

2. US8905427B2 - Convertible single and multi-seat stroller

• Full Citation: US8905427B2
• Publication/Filing Date: Publication: 2014-12-09; Priority: 2007-05-07 (Earlier than US9403550's priority date of 2008-12-04)
• Brief Description: This patent describes a convertible single and multi-seat stroller featuring a main frame with wheels and a first seat. It includes a second seat attachment that is attachable to the main frame and configured to hold a second seat. The second seat attachment may include an attachment frame with a wheel support and one or more wheels. The attachment can be pivotally connected and include a folding mechanism.
• Potential Anticipation under 35 U.S.C. § 102: US8905427B2 is highly relevant, sharing the same assignee (Baby Jogger, LLC) with US9403550 and possessing an earlier priority date. It clearly anticipates the concept of a convertible stroller accommodating multiple seats. Claim 1 of US8905427B2 explicitly states "a main frame having a set of wheels and a first seat; a second seat attachment releasably connected to the main frame, the second seat attachment including an attachment frame and a seat support configured to hold a second seat; and wherein the second seat attachment is configured to support the second seat in front of the first seat in a tandem configuration." While its abstract does not explicitly detail the "substantially below the first vertical position" or the independent "left and right seat support elements" with their dual connection points as precisely as US9403550's claims, its figures and detailed description, particularly showing a front seat in a tandem configuration, likely disclose or inherently suggest such relative positioning and supporting structures.

3. US20090302578A1 - Multiple interface stroller apparatus and systems

• Full Citation: US20090302578A1
• Publication/Filing Date: Publication: 2009-12-10; Priority: 2008-06-09 (Earlier than US9403550's priority date of 2008-12-04)
• Brief Description: This patent describes a stroller apparatus with multiple interfaces connected to the frame, where at least two of these interfaces are configured to detachably couple a child carrying member (e.g., a car seat, bassinet, or stroller seat) to the frame. The child carrying member can be detachably coupled to different interfaces.
• Potential Anticipation under 35 U.S.C. § 102: US20090302578A1 provides strong anticipation for Claims 1 and 7. Its earlier priority date and disclosure of "multiple interfaces" for "detachably coupling" child carrying members to the stroller frame, enabling tandem configurations, are directly relevant. Figures (e.g., FIG. 18 of US20090302578A1) explicitly show an "expanded stroller" with a "front seat" positioned lower and forward of a "rear seat," aligning with the relative vertical and horizontal positioning specified in US9403550's claims. The "plurality of interfaces" inherently provides the necessary left and right connection points for supporting a seat.

4. US8029007B2 - Stroller passenger assembly

• Full Citation: US8029007B2
• Publication/Filing Date: Publication: 2011-10-04; Priority: 2004-12-08 (Earlier than US9403550's priority date of 2008-12-04)
• Brief Description: This patent describes a stroller passenger assembly including a main frame, a handle, wheels, and a seat for a child. It also discloses that an additional seat can be attached to the main frame, configured to carry a second child.
• Potential Anticipation under 35 U.S.C. § 102: US8029007B2 anticipates the core concept of adding a second seat to a stroller for a second child. Figures (e.g., FIG. 1 of US8029007B2) illustrate an "auxiliary seat" that can be attached in front of a primary seat and is positioned lower than the primary seat. This aligns with the "second vertical position substantially below the first vertical position" and "closer to the front wheels" for the second seat in US9403550's claims. The attachment of such an auxiliary seat to the main frame would implicitly involve left and right support mechanisms.

5. US6045145A - Stroller with detachable auxiliary seat

• Full Citation: US6045145A
• Publication/Filing Date: Publication: 2000-04-04; Priority: 1999-07-19 (Much earlier than US9403550's priority date of 2008-12-04)
• Brief Description: This patent describes a stroller with a detachable auxiliary seat that can be attached to the front of the stroller for a second child, with the main seat positioned at the rear of the auxiliary seat. The auxiliary seat includes its own auxiliary handle and wheels.
• Potential Anticipation under 35 U.S.C. § 102: US6045145A clearly anticipates the general concept of a detachable front-mounted auxiliary seat positioned lower than a main rear seat to transport a second child. This addresses the core inventive concept of US9403550 regarding a second seat in a "second vertical position substantially below the first vertical position and closer to the front wheels." However, a key distinction might lie in US6045145A's auxiliary seat being a more independent unit with its own wheels and handle. Claims 1 and 7 of US9403550, while describing a "second seat attachment coupled to the stroller frame closer to the front wheels," specify the stroller's "plurality of wheels comprising a plurality of front wheels and a plurality of back wheels" without explicitly adding wheels to the second seat attachment itself in the claims. The description of US9403550, however, does mention embodiments with wheels for the attachment. Therefore, while it anticipates the positional relationship, the specific structural reliance on the stroller's existing wheels for the second seat attachment in Claims 1 and 7 could be a point of differentiation from US6045145A's wheeled auxiliary seat.