How to Make a Springlock Suit?

The springlock suits are composed of several individual spring-powered locking mechanisms, hence the name "springlock." When one wishes to change a springlock suit from its animatronic form into its suit form, one must insert a hand crank into its designated slot and proceed to turn it firmly into its position.

Do Springlock suits exist?

These devices actually exist in real life. Springlocks can be used to firmly hold various things back in a certain position. This is the use that is relevant to FNAF. In FNAF, Springlocks are used in the uncreatively named Springlock Suits.

Can you survive a Springlock failure?

That limb would be damaged beyond repair, but they'd live. TLDR: Short of a head or torso springlock failure, someone could survive.