Glossary > #TWIST LOCK

Dimensions of TWIST LOCK locks on the trailer

What is Twist Lock?

Twist lock is a mechanical locking mechanism essential in the logistics and transportation industry, designed to securely fasten containers to trailers, platforms, or ships. This mechanism secures containers by engaging in corner castings, creating a stable connection that prevents shifting during transport. Twist locks are a key component of intermodal transport systems, enabling smooth movement of containers between ships, trucks, and trains.

Twist locks are made from durable materials such as forged steel or cast iron and are designed to withstand heavy loads and harsh environmental conditions, such as extreme temperatures and corrosion. They come in various designs, such as fixed, sliding, or adjustable, which allows adaptation to different types of trailers and container sizes, providing operational flexibility.

Dimensions of Twist Lock Systems

The dimensions 11986 mm x 2259 mm represent the standardized spatial arrangement of twist locks on a trailer or chassis. These dimensions comply with the standards for the placement of ISO containers, ensuring compatibility with common container sizes such as 20ft, 40ft, or 45ft.

  • 11986 mm: Indicates the length of the trailer on which the twist locks are mounted, allowing the transport of various container sizes.
  • 2259 mm: Indicates the width of the trailer, ensuring proper alignment and secure attachment of containers.

This standardized arrangement enables smooth intermodal transport within global logistics networks and complies with international standards such as ISO 1161 and ISO 1496-1.

Key Components of the Twist Lock System

The twist lock system includes several important components that ensure secure attachment and efficient operation:

  1. Locking Pin: Rotates into the corner casting of the container to create a secure connection.
  2. Guide Sleeve: Directs the corner casting into the correct position for locking.
  3. Handle or Lever: Used to operate the locking pin, enabling locking and unlocking.
  4. Cover: Encloses the internal mechanisms and ensures structural strength.
  5. Safety Catch: Prevents accidental unlocking during transport.

These components work together to create a robust and reliable system for container transport.

Types of Twist Locks

Twist locks are available in various designs, tailored to specific operational requirements. The main types include:

1. Fixed Twist Locks

  • Definition: Permanently mounted on the trailer or chassis.
  • Usage: Suitable for trailers designed for specific container sizes, such as 20ft or 40ft.
  • Advantages: Durable and low maintenance.
  • Disadvantages: Limited flexibility for different container configurations.

2. Sliding Twist Locks

  • Definition: Can be slid under the surface of the trailer when not in use.
  • Usage: Suitable for multipurpose trailers that carry containers and other cargo.
  • Advantages: Provide a flat surface for loading when retracted.
  • Example Models:
    • Small Model: Sliding twist lock of size 38 mm.
    • Large Model: Sliding twist lock of size 52 mm.

3. Adjustable Twist Locks

  • Definition: Movable locks that can be adjusted to fit different container sizes.
  • Usage: Flexible trailers designed for transporting various container configurations.
  • Advantages: Versatility when handling different container sizes.

4. Double Twist Locks

  • Definition: Designed for vertical stacking of two containers.
  • Usage: Commonly used on ships or in container warehouses.
  • Advantages: Provide stability when stacking containers.

ISO Standards and Compliance

Twist locks must meet strict international standards to ensure safety and universal compatibility. These standards include:

  • ISO 1161: Specifies the requirements for container corner cutouts.
  • ISO 1496-1: Specifies the requirements for the design and dimensions of containers.
  • EN 284 and EN 452: Standards for interchangeable containers.
  • AAR M-943: Defines the structural requirements for securing containers on railcars.

The dimensions 11986 mm x 2259 mm comply with these standards, allowing for their use in global logistics.

Load Capacity and Materials

Twist locks are designed to withstand high loads and harsh environmental conditions. Key specifications include:

  • Maximum Breaking Load (MBL): Tension up to 500 kN, shear up to 420 kN.
  • Safe Working Load (SWL): Tension up to 250 kN, shear up to 210 kN.

Materials used to manufacture twist locks include:

  • Forged Steel: Provides exceptional tensile strength and wear resistance.
  • Cast Iron or Steel Casting: Cost-effective and durable alternatives.
  • Galvanized Coatings: Increase resistance to corrosion, especially in marine environments.

These specifications ensure the strength and reliability of twist locks even in demanding conditions.

Installation and Operation

Installation

Twist locks are installed on trailers or chassis in precise configurations to match the corner cutouts of containers. The installation process often involves welding or bolting, depending on the trailer’s design.

Operation

The operational process includes:

  1. Placement: Aligning the container’s corner cutouts with the twist locks.
  2. Engagement: Turning the locking pin into the corner cutout.
  3. Securing: Engaging the safety latch to prevent accidental unlocking.
  4. Unlocking: Releasing the safety latch and rotating the pin to unload the container.

Uses of Twist Locks

Twist locks are versatile and used across various transport sectors:

  1. Container Trailers: For road transport of 20ft, 40ft, and 45ft containers.
  2. Flatbed Trailers: Securing containers along with other types of cargo.
  3. Rail Transport: Stabilizing containers on railcars during long-distance transport.
  4. Sea Transport: Stacking and securing containers on cargo ships.
  5. Storage: Safely stacking containers in storage facilities.

Frequently Asked Questions

1. What do the dimensions 11986 mm x 2259 mm mean?

These dimensions define the spatial layout of the twist locks on the trailer and ensure compatibility with ISO standards for containers.

2. Can twist locks be customized?

Yes, they can be adapted for non-standard trailers or unique container designs.

3. What is the difference between fixed and retractable twist locks?

  • Fixed Locks: Permanently mounted and durable.
  • Retractable Locks: Can be retracted to create a flat loading surface.