Baby Stroller with Linked Seat Backrest Folding Mechanism

The problem

Many conventional strollers require multiple distinct operations to transition from an open, usable state to a compact, folded state. Typically, the caregiver must first release a latch on the main frame to allow the chassis to collapse, and then separately push the seat backrest down to flatten it against the seat plate before the frame can be fully folded. This multi-step process can be cumbersome, especially when holding a child or managing bags. Additionally, some designs with rotating seats have protruding latches or cables that interfere with the smooth 360-degree rotation of the seat, causing snagging or requiring complex routing of control lines.

The solution

The patent proposes a stroller frame with a seat assembly where the unlocking mechanisms are mechanically linked.

1. Frame Structure: The frame includes left and right side brackets connected by a support seat. The frame has a locking mechanism that holds it in the unfolded state.
2. Seat Assembly: The seat consists of a seat plate and a backrest. The seat plate is mounted on the support seat and can rotate 360 degrees around the Y-axis.
3. Linked Unlocking: A frame unlocking mechanism is provided on the seat plate. When activated, this mechanism not only releases the frame locking mechanism but also simultaneously releases the backrest locking mechanism.
4. Backrest Locking: The backrest is pivotally connected to the rear of the seat plate. A locking mechanism between the backrest and seat plate limits their relative rotation. This mechanism uses a gear meshing with tooth grooves, held in place by a spring.
5. Release Transmission: A steel wire connects the frame unlocking part to the backrest locking part. Pulling the wire disengages the gear from the tooth grooves, allowing the backrest to fold.

Who it is for

• Stroller Manufacturers: Brands looking to differentiate their products with simplified one-hand folding features.
• Urban Parents: Caregivers who frequently use public transport or need to store strollers in tight spaces like elevators or car trunks.
• Retailers: Stores selling premium lightweight travel systems where ease of use is a key selling point.
• Design Engineers: Teams working on modular stroller platforms that require integrated seat rotation and folding logic.

How it works

The main parts

Operating Steps

1. Normal Use: The frame is locked in the unfolded state. The backrest is fixed at an upright or reclined angle because the spring-loaded gear is engaged with the tooth grooves on the seat plate and backrest pivot.
2. Initiate Fold: The user presses or pulls the actuating member (43) on the seat plate.
3. Frame Release: The movement of the actuating member rotates the locking piece (41), which releases the frame’s structural lock, allowing the chassis to begin collapsing.
4. Backrest Release: Simultaneously, the actuating member pulls the steel wire. This wire drives a component that disengages the gear from the tooth grooves.
5. Fold Backrest: With the gear disengaged, the backrest (22) can now swing freely forward, folding flat against the seat plate (21).
6. Complete Fold: The user pushes the frame handles down, collapsing the stroller into its folded state.

Applications

Travel Systems

Parents who take strollers on airplanes or trains benefit from the quick transition to a compact form factor. The linked release reduces the time needed to pack the stroller at gates or stations.

Urban Commuting

In cities with narrow sidewalks and crowded subways, being able to fold the stroller with one hand while holding a child or bag with the other is a significant safety and convenience advantage.

Car Storage

For families using SUVs or sedans with limited trunk space, the ability to fold the backrest flat against the seat ensures the smallest possible footprint, fitting more easily alongside groceries or luggage.

Public Transport Access

Bus and train users often need to stand up quickly. The automatic release of the backrest prevents the seat from sticking up and blocking the aisle or door when the frame is collapsed.

Where it is less suitable

• Heavy-Duty All-Terrain Models: Designs focused on rough terrain may prioritize robust, separate locking mechanisms for stability over linked folding convenience.
• Simple Umbrella Strollers: Basic low-cost models often lack the complex gear-and-wire linkage described here, relying on simpler manual folding steps.