9-5/8 in 1-3/4 in Drawbar Spring

Extension springs do not have physical extension stops to prevent unexpected overloading and subsequent failure. For this reason and also for the reason that extension-spring hook stress concentrations limit the load-carrying potential, the drawbar spring evolved. The load is applied at the ends of long steel loops that pass through the spring’s center and are hooked around the opposite end, thus compressing the spring upon loading. Not only is the drawbar spring excellent for unexpected overload situations, it also offers a built-in safety feature in that upon fracturing, it will continue to carry a static load. As an example, this type design is a must when supporting a porch swing.