Cross-Linking Folding Chair Support with Sliding Joint Mechanism

The problem

Many folding chairs suffer from two main issues: bulkiness when stored and mechanical complexity that leads to failure. Traditional designs often require large, heavy hinges or multiple locking bars that add weight and cost. When folded, these chairs frequently retain a thick profile because the legs do not stack neatly against the seat plane. This makes them difficult to transport in vehicles or store in tight retail spaces. Furthermore, the repeated stress on simple pivot points can cause joints to loosen over time, leading to instability during use. Manufacturers need a solution that simplifies the kinematic chain while achieving a truly flat fold.

The solution

This patent describes a folding chair support that replaces complex multi-bar linkages with a cross-linked pole system.

1. A fixed seat (4) serves as the anchor point, containing four fixed through holes.
2. Four base poles (1) are hinged into these holes. These include two front and two rear poles.
3. Two backrest poles (2) and two armrest poles (3) have their bottoms hinged to specific sections of the base poles.
4. Crucially, the upper parts of the backrest and armrest poles carry sliding parts (sliders).
5. Each slider is hinged to the top of a base pole located on the opposite side of the chair. For example, the left front armrest slider connects to the right rear base pole’s top.
6. This geometric crossing creates parallel planes of motion. As the user pushes the seat down or pulls it up, the sliders travel along the length of the backrest and armrest poles, forcing the base poles to swing inward and align perfectly for a compact fold.

Who it is for

• Outdoor furniture brands seeking lightweight, packable camping chairs that fold flatter than standard models.
• Event rental companies needing durable, easy-to-store seating for conferences and weddings where quick setup and teardown are critical.
• Retailers of compact home furniture looking for stools or side chairs that disappear into closets or under tables.
• Product designers exploring alternative folding kinematics that reduce part count compared to traditional scissor mechanisms.

How it works

The main parts

Opening and closing

1. Unfold: Pull the armrests outward. The sliders move toward the bottom of the backrest poles.
2. Lock Position: The base poles spread apart until they hit limit stops or reach full extension, forming a stable tripod-like base per side.
3. Fold: Push the seat downward. The weight shifts, causing the sliders to move upward along the backrest poles.
4. Collapse: Because the sliders are connected to the opposite base poles, the movement forces the base poles to rotate inward and lie flat against the backrest poles, creating a thin sandwich of metal tubes.

Applications

Camping and Outdoor Events

The compact folded profile allows these chairs to fit easily into car trunks or backpacks, making them ideal for festivals, beach trips, and hiking rest stops where space is premium.

Conference and Wedding Rentals

Venue operators benefit from the rapid setup and teardown speed. The chairs stack efficiently in transport trucks, reducing logistics costs for large-scale events requiring hundreds of seats.

Small Apartment Living

Urban dwellers with limited floor space can store these chairs in narrow closets or slide them completely under dining tables when not in use, keeping living areas uncluttered.

Retail Display Units

Store fixtures often need temporary seating for customers. This design offers a sleek, low-profile look when deployed and disappears quickly when shelf space needs to be reclaimed.

Where it is less suitable

• Heavy-duty industrial tasks: The sliding sleeve mechanism may wear faster if used for frequent high-load lifting rather than static sitting.
• Extreme weather exposure: Without significant coating upgrades, standard steel tubes may rust in saltwater environments unless specifically treated.