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Carabiner gate manufacturing process enhancement.

Exploded view of a typical carabiner.

Carabiners are devices used by climbers and rescue personnel as securements in belay systems. They may be subjected to sustained or impact loads in a variety of outdoor environments. Carabiners are oval, D, or pear shaped devices, typically made from round 3/8" 7075 aluminum stock. Carabiners consist of a body and a spring loaded gate. The gate allows easy connection or release between belay system components. Some gates are locking to prevent unwanted release.

Carabiners are manufactured by either cold or hot forging techniques, and then tumbled and anodized. After the tumbling process the carabiner bodies are easy separated from the tumbling media using mechanical methods because of the difference in size between the media and the carabiner bodies. However, the carabiner gates are similar in size to the tumbling media used by some manufacturers. Manual separation has been traditionally employed, which is a costly procedure. The objective of this research is to develop less expensive alternatives to the gate separation process.

Results:

Several alternative separation methods are suggested:

• Use smaller media for tumbling the carabiner gates, enabling mechanical separation. However, some manufacturers do not find this acceptable, due to the change in the final tumbled finish.
• Use magnetic separation. The product is non-ferrous, so this process requires a magnetic media. The current media was characterized using SEM and EDS, and several possible alternative media choices were explored. Sintered Ferrite 3, BaO-6Fe2O3 was selected as the suggested replacement media.

Characterization of the original tumbling media using SEM and EDS. It was found to be Alumina Silicate. Its density was measured to be 2.51 g/cc, and its open porosity was found to be nearly zero ( 0.03).

Typical carabiner manufacturing process.