Patent Publication Number: US-10774548-B2

Title: Trowel for finishing cementitious materials

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the US national application of PCT/US2017/015491, filed on 27 Jan. 2017 and which claims priority to U.S. Provisional Application No. 62/288,098, filed Jan. 28, 2016, the disclosure of which is herein incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to construction tools and more specifically to a finishing trowel which is used to form concave surfaces. 
     2. Description of the Prior Art 
     Cementitious materials such as concrete, stucco, and plaster are routinely used in the construction of most buildings and various man-made structures. Stored as a powdery substance, this loosely mixed powder can be mixed with gravel or sand, but when water is introduced to the powder the mixture takes on a slurry-like composition which is then “worked” into a final form by evaporating residual water and continually smoothing the surface with tools designed to create a flat, smooth finish. When the material is sufficient dry, it cures or polymerizes into a hardened structure. There are other types of applicators available that create a more textured finish. 
     In many new home constructions and in some older buildings, a cement floor is incorporated into the design of the basement. This serves to create an additional room for use and to provide a means of insulating the dwelling from radon release through the ground. The basement floor is sealed by pouring a cement floor that is continuous with the walls and leveled to form a flat smooth flooring surface in contact with the walls. 
     Unfortunately, this type of basement floor does not restrict water or condensation formed on the walls to drain down and collect in a controlled fashion. Usually with this type of construction, the water runs down the wall and splays across the surface of the basement floor, resulting in a wet basement floor and making the basement susceptible to mold. 
     Conventional trowels have been used for years to shape and work the wet cementitious material in forming a flat smooth surface. These conventional trowels often have a flat, rectangular blade attached to a handle to allow the user to work the surface and form the desired finish. However, the flat blade of a conventional trowel is not effective when the surface to be worked is concave, specifically a concave tubular shape situated along the flat surface to form a channel way. 
     A round trowel has been described previously (US 2012/0180241). Unlike the present invention, this tool is completely convex on the contact surface for working within a concave area. 
     The trowel of the present invention solves the problem of creating a flat, smooth cementitious surface having a subsurface channel way molded within the curing material. Rather than having a conventional trowel form a flat smooth surface which may then be subject to being embossed with a pipe or tube, the trowel of the present invention provides a simple and efficient method of shaping and working wet cementitious material into a flat surface having a concave depression. 
     The previously described round trowel (US 2012/0180241) is a tool having a working surface that is completely convex and used for working within a concave area. The round trowel does not have a blade with both a flat and convex component on the contact portion of the blade, thereby ensuring the formation of a concave channel way along the level surface. The advantage of having a blade with this type of design is to ensure a uniform concave shape along a smooth level surface after working the wet material prior to curing. 
     SUMMARY OF THE INVENTION 
     The trowel of the present invention is similar to a conventional finishing trowel in that it has a blade with a working surface and an attached handle. However, the surface of the blade in contact with the cementitious material is not completely planar, but contains a portion having an outward curve, most preferably a convex or tubular shape along the longitudinal edge of the contact surface such that when used on the working surface creates an incurvate on the finished surface resulting, for example, in a channel way running along the direction of the trowel movement. Thus, the preferred embodiment incorporates a cementitious contact surface comprising a blade having a flat planar portion with a convex tubular portion juxtaposed along a longitudinal edge of the blade. The blade allows the user to easily form an even channel way while working the cementitious material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing the trowel with its handle and upper surface of the blade. 
         FIG. 2  is a bottom view of the blade showing the contact surface with the planar and convex components. 
         FIG. 3  is a front view of the trowel showing the front edge of the planar surface and the rounded cap on the convex surface. 
         FIG. 4  is an example of the finished cementitious surface after being worked by the trowel of the present invention during the semi-cured state. 
         FIG. 5  depicts one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings,  FIGS. 1, 2, and 3 , there are shown various views of the trowel claimed in the present invention.  FIG. 1 ,  FIG. 2 , and  FIG. 3  show views of the towel itself and  FIG. 4  depicts an exemplary surface after working with the trowel of the present invention. 
       FIG. 1  is a view of the upper side of the trowel. The handle (striped area) is attached to the noncontact surface of the blade (white area). The cap for the convex portion of contact surface of the blade is shown, providing ease of use (solid black area). The handle allows the user to grasp the trowel along the length of the blade, providing a lengthwise grasp of the trowel for easy back and forth movement along the longitudinal direction. 
       FIG. 2  is a view of the contact surface of the blade. The contact surface comprises a flat, planar portion for leveling the cementitious material into its finished surface and a convex portion preferably located along the longitudinal edge of the contact surface. The planar surface is continuous with the edge of the convex portion, resulting in a smooth seamless finished surface on the cementitious material. The shorter edges of the blade, constituting the forward and rearward edges, have an edge design commonly found for finishing trowels along the planar section, while the edge along the convex portion has a plowing edge shaped in a cap to enable the user to easily work the excess cementitious material into the surface. Other embodiments include a shape similar to a flat bottom boat, a v-shaped, round-bottom boat or any other design such as, but not limited to, straight bow, a conventional clipper bow, a low-chin spoon bow, and a high-chin spoon bow to displace a viscous mixture and provide ease of use when working the cementitious material. As shown in front face of the trowel represented in  FIG. 3 , the preferred design is a smooth, round cap (black). The handle (textured) is fixed to the upper surface of the blade (white). 
     The blade can be made from any material or composition commonly used for making similar tools. Stainless steel or fiberglass are preferred embodiments. Both materials can be easily molded into the desired contact surface, easily cleaned after use, and can be cut for manufacturing trowels in large numbers. 
       FIG. 4 a    and  FIG. 4 b    are representative drawings of a finished surface after being worked by a trowel from the present invention.  FIG. 4 a    shows a smooth flat cementitious surface, finished with the planar portion of the blade, while the channel is formed using the convex portion of the blade. The seamless interface between the convex portion and the planar portion of the blade results in a smooth edge defining the contact region of the channel way with the flat portion of the finished surface. 
     This trowel is useful for molding cementitious material where there is any need to easily form a channeled passage way within a smooth surface prior to the material curing or becoming hard. Accordingly, the trowel is ideal for viscous mixtures that eventually cure or polymerize with time such as cement or stucco. 
     In many new construction and even with older homes, builders finish the basement by installing a finished, smooth cement floor.  FIG. 4 b    depicts a finished basement floor having a channel way formed along the perimeter of the cement floor. This cement flooring prevents the buildup of radon gas which enters the home through the ground and surrounding foundation. A continuous cement floor seals off the gas and allows homeowners to more safely use the rooms within the home, including the basement without excessive exposure to radon gas. During installation of the cement floor in the basement of these dwellings, the trowel of the present invention is useful in providing a channel way along the wall on the floor surface and within the finished basement floor. This channel way prevents water seeping through the basement walls from splaying across the floor. The channel way collects the water along the edge of the floor, allowing the water to evaporate within the confines of the channel way or be directed along the channel way to a pumping means, thus eliminating the water from randomly spreading across the finished basement floor. 
       FIG. 5  depicts one embodiment of the present invention having a hollow cylindrical handle affixed to the upper surface of the blade through a tang that is affixed to the handle only at the forward and rearward ends to allow a comfortable grip. The handle is approximately 4.00 inches in length and 1.95 inches above the upper surface of the blade. The blade is 6.00 inches in length and 5.30 inches in width. The contact surface of the blade consists of a planar portion and an outward curved portion along the longitudinal edge wherein the outward curved portion incurvates a fluent cementitious surface. The outward curved portion has a depth of approximately 1.50 inches from the planar portion which is capped at the forward and rearward ends. 
     Although illustrated and described above with reference to certain specific embodiments, the present invention nevertheless is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention.