Test method for reverse ratchet torque of screw caps
In the ASTM standard catalog, the test standard for the reverse ratchet torque of the screw cap is ASTM D 3472-1997 (2002) 'Test Method for Reverse-Ratchet Torque of Type IA Child Safety Covers' (Test Method for Reverse-Ratchet Torque of Type IA Child-Resistant Closures). This test method is primarily used for torque detection of child safety covers that are rotated in a counterclockwise direction. The test equipment is a torque detector, which detects the torque of the child safety cover rotated in a counterclockwise direction (ie, the reverse ratchet torque), and no force is applied in the vertical direction. The reverse ratchet torque is a torque in the opening direction of the bottle cap, and it is also an important torque for screwing the cap. This torque cannot be lower than a certain value, otherwise the cap will be easily loosened. In general, the reverse ratchet torque is lower than 10lbf·in (1.1N·m), so the detection range of the torque detector only needs to be 0-25lbf·in (0-2.8N·m) or 0-10lbf·in (0-1.1N m). The test sample is an unused threaded screw cap with an inner cap structure, and its repeatability, it is necessary to pay attention to the influence of time, temperature and humidity conditions on the torque measurement.
![ASTM D3472 扭矩测试 ASTM D3472 扭矩测试]()
Detection steps
Place the packaging container on the torque tester and turn the outer cover of the child safety cover counterclockwise three or more times; rotate all samples smoothly and slowly at the same speed; do not create force in the vertical direction and avoid excessive Squeeze the outer cover; the maximum torque read on the torque tester is the reverse ratchet torque value.
Precautions
It should be noted that the thread structure of the screw cap, the material of the inner and outer caps, and the coating of the inner cap.
Layer material, container material, and structure all have an impact on the test results. Therefore, in the final test report, all the above conditions and factors must be clearly described.
![ASTM D3472 扭矩测试 ASTM D3472 扭矩测试]()