Extension Springs

Extension springs offer resistance to a pulling force. Different types of ends are used to attach an extension spring to the source of the force. These include threaded inserts, loops, hooks and eyes of various shapes and sizes.

Typically, round wire is used. However, square, rectangular or special section wire can also be utilized.

Most of these spring types are wound with built-in tension that holds the coil tightly together. The amount of tension is a function of the amount of force required to start separating the coils.

When designing an extension spring, consider the number of active coils as well as the load (lbs. at inch) and rate (lbs./inch).

Some end types can be integrated with initial spring manufacturing while others require a secondary operation. End design is critical because the majority of spring failures occur at the ends.

The spring insert location is critical as to size, ease of insertion, initial tension exerted, etc.

Some springs may require secondary operations such as coating, dying, passavating, etc.

Extension springs are used in every industry imaginable.

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