Compact-Fold Stroller with a Four-Bar Side Frame and Telescoping Handle

The problem

A stroller frame is folded and unfolded thousands of times. According to the patent, designs that concentrate the folding action in one or two complex hinge points make those hinges complicated and limit how many times the stroller can be folded before wear sets in. Parents also want a short, slim folded package.

The solution

1. The frame (9) carries a seat (8) and has two symmetrical side frames (1).
2. Each side frame is a foldable four-bar linkage: a handle bar (400), a front leg (100), a link (300) and a rear leg (200), hinged in sequence.
3. The handle bar meets the front leg at the first hinge (10) and the rear leg at the second hinge (20). Unfolded, the first hinge is higher than the second.
4. When folding, the handle bar and the rear leg rotate toward the front leg, approaching it from both sides, until the handle bar meets the front leg.
5. The handle bar is telescoping: an upper handle (450) slides inside a lower handle (460), which carries both hinges. A spring-loaded positioning pin in the upper handle fits a hole in the lower handle to fix the length.
6. A release switch on the handle drives a slider. A second cable from the slider pulls the positioning pin free. A locking mechanism - a notch on the front leg and a sprung lock tongue at the handle bar end - holds the frame open, and a first cable from the slider pulls the tongue out of the notch to fold.

Who it is for

• Stroller brands developing a compact or travel stroller with a durable, simple fold.
• Juvenile products companies adding a lightweight stroller to a travel-system line.
• Retailers with private-label baby gear looking for a differentiated compact frame.
• Frame and hardware suppliers to stroller brands who want a licensable-style frame concept to develop.

How it works

The main parts

Folding and unfolding

1. Press the release switch on the handle - the cables pull the lock tongue out of its notch and free the handle pin.
2. Push the handle forward and down - the handle bar and rear leg swing toward the front leg from both sides.
3. Slide the upper handle down into the lower handle to shorten the package.
4. To open, lift the handle; the lock tongue springs into its notch and the handle pin snaps into place.

Applications

Travel and airline strollers

A short, slim fold suits car trunks and overhead storage on trips.

City parents

Commuters on buses and subways need a stroller that folds quickly with one switch.

Second strollers

Grandparents and caregivers keep a compact stroller in the car.

Travel systems

The frame can take a seat or an infant car seat adapter as part of a set.

Rental fleets

Strollers rented at airports, resorts and theme parks are folded many times a day, where hinge durability matters.

Where it is less suitable

• Jogging and all-terrain strollers - these need larger wheels and suspension than a compact frame provides.
• Double strollers - a side-by-side or tandem layout needs a different frame.
• One-hand self-standing fold - if required, standing and one-hand features must be added and tested.