Concrete mixer
[citation needed] The concrete mixer was invented by Columbus, Ohio industrialist Gebhardt Jaeger.
The mixer already exhibited the still common basic construction with a tiltable conical drum (as double cone at that time) with blades.
On February 9, 1904, the first portable concrete mixer was patented by Richard Bodlaender, an inventor from Breslau, Germany.
Different styles of stationary mixers have been developed, each with its own inherent strengths targeting different parts of the concrete production market.
The concrete mixing transport truck maintains the material's liquid state through agitation, or turning of the drum, until delivery.
The drum is traditionally made of steel but on some newer trucks, fibreglass has been used as a weight reduction measure.
Most cement trucks weigh a substantial amount empty, meaning they have very heavy tare weights.
United States weight laws under the Federal Bridge Formula (FBF) require a three-axle ready mixed concrete truck to weigh 48,000 pounds (22,000 kg) or under.
The first front discharge mixer, patented in 1974, was designed and built by Royal W. Sims of Holladay, Utah, United States.
A two- or three-axle truck during the winter when road weight limits are reduced has no usable payload in many jurisdictions.
Mixers commonly have multiple steering axles as well, which generally result in very large turning radii.
[citation needed][9] Stephen Stepanian filed a patent application for the first truck mixer in 1916.
The mixing trailer system is popular with rental yards and building material locations, which use them to supply ready-mix to their regular customer base.
For smaller jobs, such as residential repairs, renovations, or hobbyist-scale projects, many cubic yards of concrete are usually not required.
A typical portable concrete mixer uses a small revolving drum to mix the components.
In hand-feed concrete mixers, cement, sand and other aggregates are directly added to the mixing drum manually.
Both of these types of concrete mixers are popular in construction activities in Africa, some Middle Eastern countries and in the Indian subcontinent.
They consist of a rotating drum mounted on an operator-driven cab-mounted chassis frame fitted with a loading bucket.
Operating concrete mixers correctly is one of the biggest safety issues in construction zones.
