Triangular Belt Connecting Hook for Child Safety Seats

The problem

Child safety seats require reliable belt connections to keep harnesses secure during travel. Traditional single-hook designs often suffer from accidental disengagement if the latch is not fully closed or if vibration loosens the mechanism over time. Additionally, connecting multiple belt straps can lead to tangling or uneven load distribution, where one strap bears more tension than others, potentially compromising the structural integrity of the restraint system. Manufacturers need a solution that ensures positive mechanical locking without relying solely on friction or simple spring-loaded clips, while also allowing for easy assembly and disassembly by caregivers.

The solution

1. Three Hook Units: The device consists of three identical hook units (1). Each unit has a shell (1.1) containing two coaxial, arc-shaped lock tongues: an inner tongue (1.2) and an outer tongue (1.3).
2. Gear Interaction: A gear (1.4) is rotatably mounted in the shell. It meshes simultaneously with gear teeth on the facing surfaces of both the inner and outer tongues. Rotating the gear causes the two tongues to move in opposite directions.
3. Pre-Connection: The three units are designed to connect together before locking. They use snap-fit grooves (1.6) and protrusions (1.7) or magnetic attraction parts to hold them in a triangular configuration.
4. Ring Formation: When pre-connected, the three inner tongues align to form a complete first circular ring, and the three outer tongues align to form a complete second circular ring.
5. Locking Action: A driving mechanism (2) activates the gear in any one of the units. This rotates both rings by a preset angle (typically 10-30 degrees) in opposite directions. Because the tongues are curved and overlapping, this rotation causes them to interlock pairwise, preventing the units from separating.

Who it is for

• Child Safety Seat Manufacturers looking for specialized internal hardware to differentiate their products from standard buckle systems.
• Automotive Interior Suppliers who provide custom restraint solutions for OEM vehicle platforms.
• Aftermarket Accessory Brands creating add-on harness connectors for strollers or specialized seating.
• Industrial Designers seeking compact, mechanically locked connection points for safety-critical applications.

How it works

The main parts

Operating Steps

1. Assembly: Snap the three hook units together using the side grooves and protrusions. The belt straps are threaded into the connecting grooves (1.5).
2. Alignment: In the unlocked state, the arc tongues are retracted within the shells. The units sit adjacent to each other.
3. Activation: Engage the driving mechanism (2). This could be a pull cord, a push button, or a lever depending on the specific implementation variant described in the claims.
4. Rotation: The mechanism rotates the gear (1.4). The gear teeth drive the inner tongue (1.2) clockwise and the outer tongue (1.3) counter-clockwise (or vice versa).
5. Interlocking: As the tongues rotate out of the shell by the preset angle, they slide past each other’s ends. The curvature ensures that once rotated, the tongues physically block the separation of the units. To unlock, the process is reversed, returning the tongues to the recessed position.

Applications

Infant Car Seat Harnesses

This hook assembly serves as a central junction for five-point harness systems. By grouping the shoulder and crotch straps into a single, rigid triangular node, it prevents strap twisting and ensures that crash forces are distributed evenly across the seat structure rather than pulling on individual anchor points.

Toddler Booster Integration

For convertible seats, the hook can act as a quick-release connector for booster mode adjustments. Caregivers can attach or detach the harness assembly with a single action, simplifying the transition between car seat modes while maintaining a high level of security against accidental opening by children.

Stroller and Travel Systems

Adapted for lightweight materials, the mechanism can be used in premium strollers to secure baby carriers or infant inserts to the frame. The compact size allows for sleeker designs compared to bulky plastic buckles, appealing to brands focused on aesthetics and ease of cleaning.

Specialized Medical Transport Seating

While not a medical device itself, the robust locking nature makes it suitable for transport chairs or hospital gurney restraints where patient security is paramount. The ability to visually confirm the locked state through the tongue positions adds a layer of safety protocol compliance.

Where it is less suitable

• High-Vibration Industrial Environments: Without additional damping, the mechanical springs might fatigue faster than solid-state electronic locks in extreme conditions.
• Single-Strap Applications: The design inherently requires three connection points; it is over-engineered for simple two-point lap belts.
• Cost-Sensitive Budget Models: The complexity of the gear and triple-shell molding increases part count and tooling costs compared to standard injection-molded buckles.