This style of spring is the ”traditional” automotive leaf spring.
Both ends of the spring are coiled into an eye into which a bush is placed. The front of the spring is captive in a spring “hanger” and the
rear of the spring is allowed to swing on shackle bolts and shackle plates around a rear “hanger” or “dumb jack” and pin.
This spring system gives smooth operation, with the parts which naturally wear over time, being able to be replaced.
Eye to eye springs are the most commonly used spring when a multi axle configuration is being considered. By linking the springs through a “rocker” assembly, a transfer of load is achieved when one axle is carrying a large percentage of the weight (crossing kerbs etc.) so that the loads are more evenly spread throughout the system.