Torsion Spring Waistband Chuck with Retractable Bell-Shaped Clamps

Patent & Production

At a glance

What the claims cover, in plain language

Claim 1 - A torsion spring type waistband chuck comprising a chuck plate and a pin. The chuck plate has a U-shaped longitudinal section with a right-side opening and a gap between upper and lower pieces. A baffle connects the left end of the gap. A clamping shaft is fixed between the upper and lower sheets at the geometric center. Two bell-shaped clamping pieces are symmetrically mounted on the shaft. A torsion spring is sleeved on the middle section of the shaft between the clamping pieces, with its claws engaging the right side edge of the clamping pieces. The spring’s elastic force and the baffle jointly hold the clamping pieces in a splayed shape. The outer ends of the clamping pieces extend beyond the chuck plate.

This is a simplified reading for orientation only. The legal scope is defined by the exact claim wording in the official Chinese document.

What this means for US production

This patent was filed in China and has lapsed, so it no longer restricts anyone in China either. The public record shows no US or other foreign counterpart.

Two points to settle early:

• Other patents may exist. Belt hardware and fastening mechanisms are a competitive field with numerous active patents globally. It is recommended to conduct a freedom-to-operate (FTO) review focusing on spring-loaded retention devices and belt tip structures before tooling.
• Material Safety. Since this component attaches to clothing worn next to the skin or as part of uniform kits, material selection must account for durability and potential regulatory requirements for metals used in consumer apparel accessories.

Customization and manufacturing

What can be customized

Things to plan for (US market)

• CPSC Lead and Cadmium Limits: For children’s products or general consumer goods, ensure metal components comply with federal limits for lead and cadmium.
• Proposition 65 (California): Screen finishes and plating materials for substances known to cause cancer or reproductive harm.
• ASTM F963 (if applicable): If marketed primarily for children, toy safety standards regarding small parts and sharp edges may apply, though adult belts typically fall under general consumer product safety.

How a project runs

1. Inquiry - Define belt compatibility, material preferences, and volume.
2. Design - Finalize plate geometry, spring rate, and clamp dimensions.
3. Prototype - Create machined or cast samples for fit and function testing.
4. Pilot Run - Assemble units and perform cycle testing for spring fatigue.
5. Production - Stamping/casting plates, winding springs, assembly, and finishing.

Quantities & timeline

Tooling costs depend heavily on whether the plate is stamped from sheet metal or die-cast. Springs are typically sourced from stock catalogs unless custom wire diameters are needed. Send us your target belt width, material preference, finish, quantity and target price and we will reply with options.

Production notes

Tooling and process

A polymer version would likely use TPU injection molding for the U-shaped plate and the bell-shaped clamps. Cutting and sewing applies to the fabric belt-tip sleeve that the clip is paired with. Metal variants would typically use cut and formed sheet, with the torsion spring sourced as a standard part.

Cost drivers

Hardware corrosion resistance likely dictates material grade; stainless steel typically costs more than plated zinc. Spring fatigue and rate consistency require careful sourcing, which affects cost. The number of belt-width sizes affects tooling complexity.

Prototyping path

Start with 3D-printed or cast components to verify the retraction angle and spring interaction. A sewn first sample integrated onto an actual belt strap would typically follow, to test real-world usage forces.

What we would change before tooling

We would likely adjust wall thickness and joint design to keep the clamps from jamming during retraction. Spring anchor points would typically be verified to prevent slippage under repeated stress.

Common failure points

Seam slippage is not relevant here, but hardware corrosion and spring fatigue are critical risks. Size deviation in the gap between the plate and clamps could hinder smooth operation.

Patent drawings

Drawings reproduced from the public patent document for reference.

Frequently asked questions

How does the belt tip pass through the loop?

The patent describes bell-shaped clamps that are held open by a torsion spring. When you push the tip through a loop, the pressure forces the clamps to fold inward into the plate, creating a slim profile that slides easily. Once clear, the spring snaps them back open to lock the belt.

Will the spring weaken over time?

The patent mentions the spring’s role in returning the clamps. In practice, spring fatigue is a factor in any mechanical device. We recommend selecting spring steel or stainless wire and confirming the spring rate consistency during prototyping to ensure long-term reliability.

Can it handle heavy-duty belts?

The design focuses on the retention mechanism. The load capacity depends on the material grade of the chuck plate and the pin attachment. For heavy tactical or industrial belts, thicker gauge metal and reinforced attachment points should be specified in the design phase.

Is it difficult to install on my existing belts?

It requires a pin connection to the belt end. Manufacturers can customize the pin hole spacing and diameter to match existing leather or webbing strap specifications, ensuring a seamless integration into current production lines.

What materials are available for the plate?

The patent does not specify materials, but typical options include stainless steel for corrosion resistance, brass for aesthetic appeal, or zinc alloys for cost-effective mass production. The choice depends on the target market and environmental exposure.

Does it work with all types of trouser loops?

It is designed to accommodate standard loops and buckles. However, extremely tight or irregularly shaped loops might resist the retraction force. Testing with your specific fabric weight and loop dimensions is advised during the prototype stage.

Can this design be made and sold in the US?

The patent was filed in China and has lapsed, and the public record shows no US counterpart, so it does not restrict the design in the US or in China. Belt hardware may be covered by other US patents - see Patent & Production - so we recommend a freedom-to-operate check before volume production.

Are you affiliated with the patent owner?

No. IP2M is an independent design and manufacturing service working from the public patent document.

Request a quote

Click Request a Quote below to see our email address - copy it, or open your email app with a ready-made message. Please mention patent CN108125324B in the subject.

Helpful details to include:

• Your company and channel (leather goods brand, uniform supplier, outdoor gear maker)
• Target belt width and thickness
• Material preference (stainless, brass, zinc, etc.)
• Finish requirement (polished, matte, plated)
• Estimated quantity and target price
• Timeline - when you would like samples and the first shipment

You can also reach us at (332) 203-9997.