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You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
     The present invention relates in general to concrete and masonry construction, and, more particularly, to an apparatus and method for introducing pigments, colorants and other additives to the surface of plastic concrete. 
     Concrete can be molded into a variety of shapes and configurations including driveways, decks, concrete masonry units (CMU), blocks, beams, columns, decorative stones, mosaics and facades as examples of decorative concrete applications. Many of these products include a colorant or pigment which provides color to the application. Concrete additives such as plasticizers, pigments, colorants or dispersants are added to concrete mixes in order to increase the plasticity of the concrete, which improves the workability of the concrete prior to hardening. Color pigments may be added to concrete mix in order to produce a certain color for aesthetic enhancement of the concrete. 
     The addition of concrete pigment and other admixtures or additives to concrete mix is known in the art. For example, U.S. Pat. No. 7,270,469 discloses an apparatus and method for adding pigmentation to a concrete mix by using a pigmentation dispenser with a hopper and two rotors wherein the pigment is dispensed onto concrete mix traveling on a conveyor. The concrete mix and dispensed pigment are then conveyed to a mixer which mixes them together. However, such methods require the addition of pigment to the entire batch of concrete to be mixed resulting in a monolithic coloring of the entire concrete mixture, some of which will never be seen or viewed as certain of the concrete structure surfaces after finishing will face the ground or other structures and remain hidden from view. As a result, there is a certain waste volume of pigment generated in such mixing and coloring regimes. Likewise, if a deeper color is required, then the entire batch of colored concrete must be reintroduced to the coloring and mixing system again resulting in the additional waste of colorant to color then entire batch of concrete to be manipulated into a slab, façade, or CMU. Moreover, these methods of adding color hardeners or additives to a concrete mix or slab are performed prior to finishing or shaping of the concrete, thereby increasing the time required to complete the process or project. 
     The addition of color additives to cast in place concrete has traditionally been by hand. As a plastic concrete slab is being finished, a worker will take a handful of powderized color hardener and disperse it over the slab, in effect flinging a handful of dry color hardener powder into the air which disperses and falls by gravity on to the wet or plastic concrete surface. A color hardener is a powder that is applied to the surface of plastic, cast in place concrete. It colors the concrete and acts to “harden” the concrete slab. 
     This method of color hardener application has serious drawbacks. For example, the color hardener powder is dispersed erratically in an uncontrolled amount and in variable concentration on to the concrete slab, which can result in a non-uniform color. Depending on prevailing environmental conditions (e.g. wind), a substantial amount of the color hardener is dispersed and deposited on other surfaces close to the slab and goes to waste, as well as potentially bleeding color undesirably on other surfaces. A more serious drawback is that the powder may be inhaled by the worker and other workers on the site, potentially leading to detrimental physiological effects (sneezing, asthma or other undesirable health conditions). As a result, a need exists for an apparatus and method which effectively and safely broadcasts concrete color hardener or other additives on to a plastic cast in place slab. 
     Therefore, one object of the present invention is to provide an apparatus and method for the controlled dispensation and application of concrete colorants or additives to concrete surfaces without the need to monolithically mix such colorants or additives prior to finishing or manipulation of the concrete into the desired shape or structure. 
     A further object of the present invention is provide an apparatus and method which provides a mechanism by which pigments or other additives may be introduced to the concrete mixture in specific areas in the discretion of the operator as the concrete is being finished. 
     A further object of the present invention is the provision of an apparatus and method for introducing color hardener or other additives to concrete mix which is efficient in operation and conserves the volume of additive required to complete the concrete treatment process. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a method and apparatus for broadcasting dry color hardener while finishing a concrete surface is provided as disclosed herein. The apparatus comprises a concrete float with a vibratory broadcaster assembly attached therewith. The broadcaster assembly is suspended above the plane of the finishing tool, such as a bull float or other finishing tool, with a vibratory source attached. The broadcaster assembly is filled with color hardener or other additive and the apparatus is placed on a wet, concrete surface which is to be treated and finished by a user. Actuation of a power switch activates the vibratory source resulting in the substantial broadcast of color hardener on to the plastic concrete surface at the desired location(s) as determined by the user. The color hardener or other additive is then integrated into the concrete by passage of the float or finishing tool over the concrete surface. 
     Other technical advantages of the present invention will be readily apparent to one skilled in the art from the following figures, descriptions and claims. While specific advantages and embodiments have been enumerated above, various embodiments may include all, some, or none of the enumerated advantages. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of the broadcast float tool assembly apparatus as used in a typical concrete finishing operation in accordance with the present invention; 
         FIG. 2  is a close-up perspective view of the broadcast float assembly in accordance with the present invention; 
         FIG. 3  is a bottom perspective view of the broadcast float assembly in accordance with the present invention; and, 
         FIG. 4  is a rear perspective view of the broadcast float assembly in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For purposes of teaching and discussion, it is useful to provide some overview as to the way in which the invention disclosed herein operates. The following information may be viewed as a basis from which the present invention may by properly explained. Such information is offered for purposes of explanation only and, accordingly, should not be construed to limit the broad scope of the present invention and its potential applications. 
       FIG. 1  depicts a user  2  operating the broadcast float device  4  on a typical concrete surface  12  finishing job. As will be described in further detail hereafter, the broadcast float assembly  4  is operated by user  2  manipulating an extendible pole  6  which is detachably secured to the broadcast float assembly  4 . Color hardener or other additive  8 , which may be in granular, powder, or pelletized form, is added to and suspended above the concrete surface by the broadcaster assembly  4  then dispersed on to the concrete slab  12  from the broadcast assembly  4  by actuation of a vibratory source controlled by switch  10  which vibrates the broadcast assembly in such fashion as to broadcast the additive on to the surface of concrete slab  12 . 
     In one embodiment, the switch  10  may detachably secured on or about the person of user  2 , such as clipped to the user&#39;s belt or suspended about the user  2  with a strap or button. This allows the user  2  to broadcast the color hardener  8  in areas on surface  12  as desired without the aid of additional persons. In another embodiment switch  10  may rest on the ground, along with variable control switch  32  or without, and be controlled by the user  2  or another person as desired. As shown in  FIG. 1 , the treated concrete surface  14  denotes the effect of application of an additive  8  thereto in this case shown as a concrete colorant, while concrete surface  12  remains untreated with additive  8 . In another embodiment, switch  10  includes a variable speed switch  32  so as to allow the user  2  to adjust speed of vibratory cycles applied to the broadcast float assembly  4  thereby increasing or decreasing the amount of additive  8  which is broadcast on to the concrete surface  12 . 
     Turning to  FIG. 2 , the broadcast float assembly  20  components are shown in further detail. Broadcast float assembly  20  includes a float plate  22 , a float plate mount bracket  24 , a tool receiver  26 , a broadcaster  28 , and a vibratory source  30  with controller switch  32  in electrical communication with vibratory source  30  via cord  34 . Electrical power is supplied to the control switch  32  and vibratory source by connecting plug  36  to an electric power source of appropriate voltage, which in typical application is 110 volts-220 volts. In another embodiment, electrical power is supplied by battery, generator or other capacitance means as known in the art. For example, a 24 Volt battery pack would provide adequate power for operation of the device  4  when it is being used in locations where direct electrical power is not available or easily accessed. It is contemplated that in other embodiments the broadcast float assembly  20  may be used with or integrated with other floats, screeds, tampers or other concrete finishing equipment as known in the art. 
     Broadcaster  28  includes screen  42  secured to screen frame  44 . Screen  42  is comprised of a mesh or metal type screen with holes of punched therein to allow for additive flow through the screen  42  upon activation of the vibratory source  30  which imparts vibrations or shockwaves to the broadcaster  28  causing the dispersion of additive through the holes in screen  42 . In one embodiment, screen  42  is made of 050 gauge aluminum metal with 3/32 inch diameter staggered holes punched therein. Screen frame  44  is constructed of aluminum metal or other suitable structural material. Screen frame  44  acts to support screen  42  and also as a containment wall around the perimeter of screen  42  for keeping the additive poured on to the screen  42  surface in place and ready for application. In one embodiment, screen frame  44  is made of aluminum metal tubing or channel of sufficient strength to contain and support screen  40  when loaded with additive for broadcast. In the embodiment shown, vibratory source  30  is attached to the broadcaster  28  by weld, bolt or other attachment means as known in the art. 
     Broadcaster  28  is secured to and supported by float plate  22  via upper supports  38  and lower supports  40 . The upper supports  38  and lower supports  40  are secured to the float plate  22  via the float plate mount bracket  24  by weld, bolt or other attachment means as known in the art. Upper supports  38  and lower supports  40  are secured to the broadcaster  28  by weld, bolt or other attachment means as known in the art. Vibratory source  30  is detachably secured to the broadcaster  28  by weld, bolt or other attachment means as known in the art. Vibratory source  30  may be attached to the broadcaster  28  at any suitable attachment point and its position shown in the Figures herein is not to be construed as a limitation of the architecture disclosed herein. 
     With reference to  FIG. 3 , the broadcast float assembly is shown from a bottom perspective view. Lower supports  40  are depicted in greater detail and shown supporting the broadcaster  28  in the horizontal plane above the plane of the float plate  22 . In one embodiment, the broadcaster  28  is suspended between one to six inches above the horizontal float plate  22  plane. Various heights may be utilized depending on the desired broadcast range or the application or environmental conditions (wind conditions) prevailing at the time of additive broadcast. In one embodiment, the broadcaster  28  height above the float plate  22  may be adjusted by loosening/tightening bolts, screws, nuts or latching/unlatching pins located at the attachment points for the upper supports  38  and lower supports  40 . It is contemplated that in alternative embodiments adjustable connections or connector means may be utilized to allow the operator to adjust the height of the broadcaster  28  relative to the float plate  22  as desired. 
     Turning to  FIG. 4 , a rear perspective view of the broadcast float apparatus is shown. In this embodiment, four lower supports  40  are shown with two upper supports  38  shown extending across the top portion of the broadcaster  28 . Upper supports  38  are shown attached to the broadcaster  28  via channel supports  50  which are secured to screen wall  44  and to the float plate mount bracket  24  via channel supports  52 . Lower supports are shown attached to the float plate mount bracket via channel supports  46 . Channel supports  46 , 50  may optionally be fashioned out of metal or other structurally sufficient materials in various shapes such as tubing, channel, rod or other geometric shapes capable of providing sufficient support for the broadcaster  28  to the float plate  22 . 
     In the depicted embodiment, vibratory source  30  is comprised of an electric motor with offset weights attached to a driveshaft dispensed therein so as to provide a source of vibrations or shock waves sufficient to induce the flow of additive resting on the top surface of screen  42  through the holes in the screen  42  and down on to the concrete surface being finished. A variable speed vibratory device may be utilized with the vibratory cycle speed controlled by the user via the control switch or a variable speed switch or both. As the cycle speed is increased, the amount of color hardener or additive broadcast increases, thereby resulting in a higher concentration of additive being applied to the concrete surface. As the vibratory cycle speed is lowered, smaller volumes of color hardener or additive are dispersed resulting in lower concentrations being applied to the concrete surface. 
     In application and with reference to the all of the figures herein described, a user can utilize the broadcast float apparatus  10  to selectively apply additives to the desired areas of a concrete slab which is being finished. For example, a spotted color pattern could be easily colored into the concrete using the apparatus and method disclosed herein. Additionally, the apparatus  10  allows a user to apply color hardener or other additives in areas of a plastic slab where traditional “hand throwing” techniques could not be utilized. The operator may simply add the requisite number of tool extension poles to position the apparatus  10  in the desired area for the broadcast of color hardener or other additives. Likewise, in other embodiments of the invention it may be desirable to use a plasticizer in select portions of the plastic slab being finished to alter or extend the curing time for a certain portion of the slab. This would facilitate light foot traffic on portions of the untreated slab and allow users to insert forms, columns or other objects in select areas of the slab which have remained in a plastic, uncured state. 
     While the invention has been particularly shown and described with reference to a various embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

Summary:
The apparatus and method comprise a concrete float with a vibratory additive broadcaster assembly attached therewith. The broadcaster assembly is suspended above the plane of the finishing tool with a vibratory source attached. The broadcaster assembly is filled with an additive and the apparatus is placed on a wet, concrete surface which is to be treated and finished, by a user. Actuation of a power switch by the user activates the vibratory source resulting in the substantial broadcast of additive on to the concrete surface at the desired location(s) on the slab as determined by the user. The additive is then integrated into the concrete by passage of the float over the treated concrete surface.