Double Spring Draw Latch 147N Nickel Plated for Flight Cases

5502-59-FE-NI Double Spring Damper Latch - Nickel Plated Mild Steel Spring Latch Set

Specifications

Product Overview & Positioning

The 5502-59-FE-NI is a double spring latch set from NRH's 5502 series. This model is manufactured from premium mild steel with a nickel plating finish, offering good corrosion resistance and a bright silver-white appearance. As a double spring latch, it features a built-in spring mechanism and comes as a complete set including both the latch hook and strike plate, making it suitable for 147N-rated vibration-resistant latching applications in flight cases, heavy-duty luggage, firefighting cases, and industrial machinery.

Key Features

• Double Spring Mechanism: Built-in dual spring design provides extension and retraction during opening/closing, automatically tensioning the lid for stable case sealing.
• Vibration Damping Function: The dual spring system absorbs mechanical vibration and shock during transport and operation, preventing accidental lid opening and reducing noise.
• Over-Center Self-Locking: Combines lever and over-center mechanism. When fully pressed flat, the mechanism self-locks - external vibration actually tightens the latch further.
• Nickel Plated Mild Steel: Mild steel base offers good stamping formability and structural strength; nickel plating provides a smooth, decorative surface with better corrosion resistance than standard zinc plating.
• Complete Latching Set: Includes both hook and strike plate - no additional parts required.

Working Principle Explained

The 5502-59-FE-NI is a double spring latch. Its working principle is spring-loaded extension and retraction.

• Open State: The hook pivots on a fixed base plate. When lifted upward, the spring stretches and the hook disengages from the strike plate.
• Closing Process: When pressed downward, the hook slides into the strike plate opening. As the latch approaches horizontal, the double spring provides retraction force, automatically pulling the latch into the locked position.
• Locked State: Once fully pressed flat, the mechanism passes the over-center point and self-locks. The double spring maintains continuous tension, keeping the lid tightly sealed. When external vibration occurs, the spring system absorbs impact energy while the over-center lock prevents reverse opening.
• Enhanced Sealing: The continuous tension from the double spring compensates for gasket aging or thermal expansion/contraction, maintaining consistent sealing performance over time.

Material & Finish Advantages

Mild Steel: With carbon content below 0.25%, mild steel offers excellent ductility and stamping formability for precision latch components. Yield strength is approximately 200-250 MPa, sufficient for 147N static load without permanent deformation. It is cost-effective and widely used for industrial latches.

Nickel Plating: An electrochemical process deposits a layer of nickel onto the mild steel substrate. Nickel plating provides good corrosion resistance, wear resistance, and a uniform, bright silver-white finish. Compared to zinc plating, nickel plating offers a smoother, more decorative surface with better oxidation resistance. It is suitable for applications where appearance matters. Nickel plating also offers good solderability and electrical conductivity, making it suitable for electronic equipment cabinets. Note that nickel plating may still corrode in long-term humid or salt spray environments, so regular inspection is recommended.

Installation & Usage Guide

Based on the drawing, key dimensions: overall length approx. 65.5mm, two Ø4.2mm mounting holes. Installation steps:

• Tools: Ø4.3mm drill bit, M4 tap (for metal cases), screwdriver.
• Marking: Place the hook on the lid edge and mark its 2 hole positions. Close the lid, place the strike plate on the case body aligned with the hook, and mark its 2 holes.
• Drilling: Drill Ø4.3mm holes. For plastic or wood, use self-tapping screws. For metal, tap M4 threads or use rivet nuts.
• Screw selection: Use M4×8-12mm stainless steel pan head screws with anti-rust washers. For vibrating environments, use medium-strength threadlocker (e.g., Loctite 243).
• Alignment: Loosely mount both parts, close the lid, and press the latch. The spring should provide proper retraction force.
• Anti-vibration: Check screw tightness every 6 months.

Typical Applications

Based on the 147N load capacity, nickel plating, and double spring damping characteristics, this latch is suitable for:

• ATA Flight Cases: Stage audio, film camera equipment, drone transport cases. Double spring absorbs transport vibration, protecting sensitive equipment.
• Heavy-Duty Luggage: Professional tool travel cases, large camera equipment cases. Spring provides continuous tension for stable sealing.
• Firefighting Cases: Personal protective equipment cases, rescue tool storage boxes. Spring mechanism ensures reliable locking even under severe vibration.
• Industrial Machinery Enclosures: Cabinet access doors, control panel covers, vibrating screen enclosures. Spring absorbs equipment vibration, preventing loosening.
• Medical Equipment Cases: Portable diagnostic devices, emergency kits. Nickel plated surface is easy to clean.
• Trunk Cases & Export Crates: Wooden crates, plywood boxes. Spring compensates for temperature/humidity-induced seal gap changes.
• Instrument Cases: Precision instrument transport cases, laboratory equipment boxes. Double spring provides smooth latching force, protecting sensitive instruments.

Ordering & Compliance Information

This product is a complete latching set (hook + strike plate). Certifications (e.g., RoHS, REACH) are available upon request. OEM/ODM customization including laser marking and special packaging is supported.