Topological synthesis and integrated kinematic-structural dimensional optimization of a ten-bar linkage for a hydraulic rescue spreader

Hydraulic rescue spreaders are used by emergency response personnel to extricate occupants from a vehicle crash. A lighter and more portable rescue spreader is required for better usability and to enable utilization in a variety of scenarios. To meet this requirement, topological synthesis, dimensional synthesis, and an optimization were used to develop a solution linkage. The topological synthesis technique demonstrates that ten links are the minimum possible number that achieves the desired motion without depending primarily on rotation of the spreader jaws. A novel integrated kinematic-structural dimensional synthesis technique is presented and used in a grid-search optimizing the linkage dimensions to minimize linkage mass. The resulting ten-bar linkage meets or exceeds the kinematic performance parameters while simultaneously achieving a near-optimum predicted mass.