US Patent 7237977 Turnbuckle load indicator

A load indicator for a spring loaded tensioning device. The indicator comprises an o-ring displaceable along a spring loaded tensionable shaft in a turnbuckle device. When the turnbuckle is unloaded, the indicator device is placed in a known position relative to an indicating mark. When the turnbuckle is loaded, the load causes the load indicator to be displaced a known distance for a known load on the spring loaded turnbuckle. For camper tie-downs, a displacement of about one-quarter inch is desirable for a load of about 300 pounds tension.