Understanding Extension Spring End Types
Extension springs are designed with two basic end types – hooks and loops. Hooks have a gap, while loops are fully closed all the way around. Most of our stock extension springs have loop ends, but they can be easily cut into a hook if required. Both hooks and loops come in a few different style options to match specific needs. The most commonly used end styles for extension springs include crossover, machine style, side style, and double loop ends.
Crossover and machine style ends are the standard end styles. On a crossover style, the wire crosses over the center of the spring. The machine style end has the wire coming from directly out of the spring body. Both function the same way, with crossover ends being mostly used on small springs and machine ends mostly on larger springs.
Extension springs with side style ends mean that the hooks and loops sit on the same plane as the spring body. In the case of double loop ends, the extra loop strengthens the ends to prevent loop breakage.
The last factor to consider is the relationship of ends. A random position is the most common and least expensive option. If required, we also can manufacture ends to hold specific relationships. The three most common are – inline, opposite, and 90 degrees. In cases that require a different relationship of ends, our team is able to work with custom designs to meet specific needs.