How does self-locking helicoil work?

Self-locking Heli-Coil, also known as a self-locking threaded insert, works by combining the features of a traditional Heli-Coil or wire thread insert with a locking mechanism designed to prevent the fastener (screw or bolt) from coming loose due to vibration, shock, or other external forces. Here’s how a self-locking Heli-Coil works:

1. Coiled Insert: Like a standard Heli-Coil or threaded insert, a self-locking Heli-Coil is a helically wound coil made from metal wire. It has internal threads that match the external threads of the fastener to be used.

2. Tang or Locking Feature: What sets a self-locking Heli-Coil apart is the presence of a locking feature within the coil. This locking feature can take various forms, but one common design includes one or more tangs or coils within the internal threads of the insert.

3. Installation: The self-locking Heli-Coil is installed into a pre-drilled hole in the material, just like a standard Heli-Coil. During installation, the tangs or coils within the insert engage with the threads of the fastener as it is screwed into the insert. This engagement creates resistance against the fastener rotating counterclockwise (loosening).

4. Friction and Compression: As the fastener is threaded into the self-locking Heli-Coil, the tangs or coils within the insert create friction and compress against the threads of the fastener. This friction and compression generate a locking effect, preventing the fastener from rotating freely in the opposite direction.

5. Resistance to Loosening: Due to the locking mechanism, the self-locking Heli-Coil provides resistance to loosening caused by vibration, shock, or other external forces. This makes it particularly suitable for applications where maintaining a secure threaded connection is critical.

6. Reusability: In many cases, self-locking Heli-Coils are reusable. If the fastener needs to be removed and replaced, the insert can often be used again without losing its locking capabilities.

Self-locking Heli-Coils find applications in various industries, including aerospace, automotive, manufacturing, and machinery, where preventing fastener loosening is essential for safety and performance. The locking feature within the insert provides an additional layer of security and reliability in threaded connections, making it a valuable component in engineering and manufacturing processes.