Reverse Ratchet Torque

Reverse ratchet torque testing is an essential process for verifying the safety and reliability of child-resistant closures (CRCs). It measures the torque required to rotate a closure in the reverse direction once the ratchet mechanism engages. This ensures the safety function is maintained even when the closure is subjected to unintended or excessive force.

Reverse ratchet mechanisms are engineered to resist opening by children while remaining functional and accessible for adults. Torque testing validates that these mechanisms engage correctly and deliver the necessary resistance to prevent accidental access to hazardous products.

In practice, reverse ratchet torque testing is used for:

• Safety validation - confirming closures function as intended under reverse force
• Regulatory compliance - demonstrating that closures meet international packaging safety standards
• Quality consistency - detecting manufacturing or assembly defects before products reach the market

Child-resistant closures are a critical safety feature for packaging containing pharmaceuticals, chemicals, and other hazardous substances. They reduce the risk of accidental ingestion or misuse by children, while remaining convenient for adult users.

Torque testing ensures that:

• The closure maintains integrity after repeated use
• The reverse ratchet mechanism functions consistently under normal and extreme conditions
• Manufacturing variations do not compromise safety performance

Regulatory agencies such as the FDA in the United States, and equivalent bodies in other regions, require manufacturers to prove that CRCs meet defined torque performance standards. Failure to comply can result in product recalls, penalties, and reputational damage.

A range of recognised standards define the correct procedures for reverse ratchet torque testing, ensuring consistent and reliable results.

ASTM D3472

Specifies the method for determining reverse ratchet torque for Type IA child-resistant closures. Covers sample preparation, test speed control, and torque measurement accuracy requirements.

ASTM D3810

Defines the minimum application torque required for CRCs to function effectively. It complements reverse ratchet torque testing by verifying that closures are applied tightly enough for the safety mechanism to engage.

BS EN ISO 13127

Widely applied in Europe, this standard outlines similar test methods but may differ in sample conditioning, torque measurement tolerances, and fixture specifications.

For manufacturers supplying multiple regions, understanding the differences between ASTM and BS EN ISO requirements is essential to maintaining compliance across markets.

Sample preparation

Condition the closures according to the specified standard to control environmental factors.

Fixture setup

Use a correctly designed mandrel to hold the closure securely, ensuring no slippage and accurate engagement of the ratchet mechanism.

Top-load application

Apply a controlled axial load, typically via a pneumatic top-load system, to replicate real-world handling conditions.

Torque application

Rotate the closure in the reverse direction at the specified rate until the ratchet mechanism engages and resistance is measured.

Recording results

Capture peak torque values in N·m or lbf·in and compare against specification limits.

Repetition and averaging

Perform multiple tests per batch to ensure result repeatability and compliance.

Mandrels

Custom-designed mandrels ensure closures are aligned and secured during testing. Correct mandrel design prevents slippage and eliminates fixture-induced variability.

Pneumatic top-load control

A pneumatic top-load system applies consistent downward pressure, removing operator variability and improving repeatability.

Implementing torque testing in quality control

Incorporating reverse ratchet torque testing into a QC programme helps to:

• Maintain regulatory compliance
• Detect defects early in the production process
• Optimise manufacturing by adjusting parameters based on test feedback

Testing frequency is determined by product risk, production volume, and compliance requirements. Operators should be trained in the correct use of fixtures, equipment, and data capture systems.

Mecmesin offers torque testing systems engineered to meet the precise demands of child-resistant closure testing. Our equipment provides accuracy, repeatability, and flexibility for both laboratory and production environments.

Technical advantages include:

• Compliance with ASTM, BS EN, and ISO standards
• Configurable fixtures for different CRC designs
• High-precision load cells for dependable measurement
• Systems including the Vortex, Vortex-xt, OmniTest, and MultiTest-dV for a wide range of test capacities
• VectorPro software for digital capture, analysis, and reporting of torque data

Mecmesin torque testers are used by packaging engineers, quality control teams, and compliance specialists to ensure CRCs meet strict safety requirements while maintaining usability for adult consumers.

To discuss your reverse ratchet torque testing requirements and find the most suitable Mecmesin solution for your application, speak to one of our technical experts today.