This invention relates to a concrete mixer and more particularly to a mobile concrete mixer which may be utilized to mix concrete materials in either a continuous or batch type manner. Further, the mobile concrete mixer of this invention includes means for selectively vertically adjusting the discharge height of the same.
Historically, concrete has been mixed in a variety of devices such as rotary drum mixers, pug mills, vertical shaft turbine mixers, tub type ribbon mixers, etc.
Rotary drum mixers are, by nature, limited in mixing speed due to the presence of centrifugal force within the drum which requires longer mixing time to achieve the required mixing. Rotary drum mixers are normally tilted to discharge the materials therefrom which means that the mixed concrete must be gathered in a collecting hopper to regulate transfer into hauling units. The requirement of such hoppers, and the bulk of the drum design, results in discharge height requirements which are not compatible with mobile concrete plants.
Turbine mixers, which normally have a vertical shaft and mixing plows rotating within a circular housing, will mix the concrete materials faster than a rotary drum mixer but the diameter of the turbine mixers necessarily becomes excessively large when the capacity of the same is increased to equal the desired batch capacity of approximately ten cubic yards.
Tub type ribbon mixers are likewise large and bulky and require a discharge collecting hopper or a discharge conveyor which is not suitable for use with mobile concrete plants.
Pug mill type mixers, with the usual dual counter rotating shafts with mixing paddles, require heavy construction, wear-reducing side plates, high horsepower, and close tolerances between the rotating paddles and the housing to ensure complete mixing of the batch. Such pug type mixers also require a large discharge type collecting hopper which likewise increases height requirements and causes the same to be incompatible with mobile concrete plants.
The mobile concrete mixer disclosed in the co-pending application represents a significant advance in the art and overcomes the disadvantages of the prior art. The instant invention is an improvement over the invention described in the co-pending application in that it eliminates any possibility that rocks or stones may be wedged beneath the mixing devices in the hopper which could possibly cause wear to the conveyor belt or damage thereto.
It is therefore a principal object of the invention to provide a high capacity mobile concrete mixer.
Yet another object of the invention is to provide a mobile concrete mixer which has a low-charging height and an adjustable discharge height which may be utilized with any mobile or stationary batching system for either batch type mixing or continuous type mixing.
Still another object of the invention is to provide a mobile concrete mixer which may be used to mix concrete in either a continuous or batch type manner.
Still another object of the invention is to provide a mobile concrete mixer which is designed to mix aggregate, cement and water in either a batch fashion or in a continuous fashion and convey the mixed concrete into hauling units such as dump trucks, agitator trucks, mobile concrete mixers or the like.
Yet another object of the invention is to provide a mixer of the type described which may be utilized to transfer mixed concrete into hoisting buckets or pump units.
Yet another object of the invention is to provide a mobile concrete mixer which eliminates the need for a batch hopper as in prior art devices.
Still another object of the invention is to provide a mobile concrete mixer wherein an elongated conveyor means is mounted upon a wheeled frame means which may be pulled by a prime mover and wherein the conveyor means may be raised or lowered to vary the discharge height thereof.
A further object of the invention is to provide a mobile concrete mixer including a unique mixing apparatus located within a hopper positioned over a conveyor belt with the mixer being designed to not only properly mix the concrete materials but to also ensure that the same is mixed with a minimum of horsepower being required.
Yet another object of the invention is to provide a mobile concrete mixer of the type described which prevents rocks or stones from being wedged beneath the mixers in the mixing hopper thereby preventing damage to the conveyor belt.
Yet another object of the invention is to provide a device of the type described including a plurality of vertical mixing devices, the motion of which is such that the materials in the hopper will be transported from one mixing device to the next to ensure proper mixing of the agregate materials in the hopper.
These and other objects will be apparent to those skilled in the art.