Concrete Mixer

A concrete mixer is a device that homogeneously combines cement, aggregate such as sand or gravel, and water to form concrete on site, typically using a revolving drum fitted with an internal spiral blade. T.L. Smith of Milwaukee built one of the earliest models around 1900 with a tiltable conical drum, and the German inventor Richard Bodlaender patented the first portable concrete mixer, a horse-drawn machine called the Mortar Mixer, on February 9, 1904; Roscoe Lee later patented the transit mixer design in 1934, allowing a rotating drum to be mounted on a truck and deliver ready-mixed concrete to a job site. The concrete mixer let construction workers prepare concrete close to where it would be used, giving crews enough working time before the material hardened.