US Patent 7942142 Battery powered concrete saw

A concrete saw (10) has an electric motor (24) energized by a battery pack (34) to drive a pair of saw arbors (42) and a battery powered transmission (30) drives rear wheels (16) that provide self propulsion of the saw in cooperation with front wheels (20). A power operated actuator (54) raises and lowers the front wheels (20) to provide upward and downward movement of the saw frame (14) about its rear wheels (16). The battery pack (34) may be lead acid batteries, nickel-cadmium batteries, nickel metal hydride batteries or lithium batteries, and the electric motor (24) has 5 to 15 horsepower, preferably about 10 horsepower, to provide cutting of most conventional concrete jobs.