Patent Publication Number: US-10787825-B2

Title: Trowel

Description:
PRIORITY 
     This application is a divisional of U.S. Ser. No. 14/071,847 filed on Nov. 5, 2013. 
    
    
     FIELD 
     The present disclosure is generally related to trowels and, more particularly, to a trowel for the application of a curable material, such as an adhesive or mortar, to a surface. 
     BACKGROUND 
     Adhesive bonding is a common way of fabricating various kinds of components, such as aircraft components. When bonding parts of a component together, a specific amount of adhesive is used to ensure proper bonding of the component. The specific amount of adhesive is typically quantified as the thickness of the layer of adhesive. 
     However, adhesive application between bonded surfaces of a component can be an inexact process. The process typically includes dispensing an approximate amount of the adhesive to the bonded surface. The adhesive is then spread and leveled on the bonded surface to form an intermediate layer of adhesive having a required and/or desired thickness. A straight edge (e.g., a flat-edged trowel) or a notched trowel (e.g., a plurality of square or triangular teeth disposed on a working edge) may be used to spread and level the adhesive on the bonded surface. 
     Unfortunately, use of a straight edge to level the adhesive may provide an inexact and/or inconsistent thickness of the intermediate layer. Further, use of a notched trowel may be sensitive to the angle of the notched trowel with respect to the bonded surface to which the adhesive is applied (e.g., as the angle of the notched trowel with respect to the bonded surface changes, the thickness of the intermediate layer of adhesive may also change). For example, using a conventional notched trowel disposed at a 90° angle with respect to the surface to which the adhesive is applied may yield an intermediate layer having a first thickness. Using the same notched trowel disposed at a 45° angle with respect to the surface to which the adhesive is applied may yield a second thickness. The second thickness may be considerably less than the first thickness (e.g., approximately 70% of the first thickness). Given the human element of the spreading and leveling process, the overall thickness of the intermediate layer of adhesive may vary across the bonded surface. 
     Thus, the use of a straight edge or a notched trowel may lead to too little adhesive or too much adhesive being applied to the bonded surface. Too little adhesive may lead to an insufficient bond between bonded surfaces of the component. Too much adhesive may squeeze out from between bonded surfaces of the component and/or may form a bond line that is too thick. To avoid applying too little adhesive, operators may use too much adhesive and remove (e.g., clean up) any excess adhesive that may squeeze out. This excess adhesive removal process may take longer than the application process and requires that excess adhesive be properly disposed of due to hazardous chemicals in the adhesive compound. To avoid having to clean up excess adhesive, operators may use too little adhesive, which may cause improper bonding and possible failure of the component. 
     Accordingly, those skilled in the art continue with research and development efforts in the field of application of a curable material to a surface. 
     SUMMARY 
     In one embodiment, the disclosed trowel may include at least one working edge, and a plurality of radial teeth extending from the working edge. 
     In another embodiment, the disclosed trowel may include a main body including at least one working edge, the working edge including an edge radius, a plurality of radial teeth extending from the working edge, each radial tooth of the plurality of radial teeth including a radial edge and a tooth radius, and wherein a distance between the edge radius and the tooth radius at any point along the working edge is the same. 
     In another embodiment, also disclosed is a method for uniformly applying an intermediate layer of curable material to a surface, the method may include the steps of: (1) applying an initial amount of the curable material to a surface; (2) moving the trowel across the surface to spread and level the initial amount of curable material; wherein, during the moving step, the trowel is positioned at a non-zero angle relative to the surface; and wherein the trowel spreads and levels the initial amount of curable material to a constant thickness, the constant thickness being independent of the non-zero angle. 
     In yet another embodiment, also disclosed is a method for applying a layer of curable material to a surface, the method may include the steps of: (1) applying the curable material to the surface; (2) positioning a trowel relative to the surface so that a plurality of first radial teeth of the trowel, extending from a working edge of the trowel, is in contact with the surface; and (3) with the plurality of first radial teeth in contact with the surface, moving the trowel across the surface to spread the curable material across the surface at a constant thickness. 
     Other embodiments of the disclosed trowel will become apparent from the following detailed description, the accompanying drawings and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front and side perspective view of one embodiment of the disclosed trowel; 
         FIG. 2  is a partial side elevational view, in section, of the trowel of  FIG. 1 ; 
         FIG. 3  is a partial side elevational view, in section, of another embodiment of the disclosed trowel; 
         FIG. 4  is a front and side perspective view of one implementation of the disclosed trowel depicted at a first angle with respect to a surface to which a curable material is applied; 
         FIG. 5  is a side elevational view of the trowel of  FIG. 4 ; 
         FIG. 6  is a side elevational view of another implementation of the disclosed trowel depicted at a second angle with respect to the surface to which a curable material is applied; 
         FIG. 7  is a side elevational view of another implementation of the disclosed trowel depicted at a third angle with respect to the surface to which a curable material is applied; 
         FIG. 8  is front and side perspective view of one embodiment of a radial tooth of the trowel of  FIG. 1 ; 
         FIG. 9  is a front elevational view of the radial tooth of  FIG. 8 ; 
         FIG. 10  is front and side perspective view of another embodiment of a radial tooth of the trowel of  FIG. 1 ; 
         FIG. 11  is a front elevational view of the radial tooth of  FIG. 10 ; 
         FIG. 12  is front and side perspective view of another embodiment of a radial tooth of the trowel of  FIG. 1 ; 
         FIG. 13  is a front elevational view of the radial tooth of  FIG. 12 ; 
         FIG. 14  is a front and side perspective view of another embodiment of a radial tooth of the trowel of  FIG. 1 ; 
         FIG. 15  is a front elevational view of the radial tooth of  FIG. 14 ; 
         FIG. 16  is a front and side perspective view of another embodiment of the disclosed trowel; 
         FIG. 17  is front elevational view of another embodiment of the radial tooth of the trowel of  FIG. 16 ; 
         FIG. 18  is a front and side perspective view of another embodiment of the disclosed trowel; 
         FIG. 19  is a side elevational view of another embodiment of a radial tooth of the trowel of  FIG. 18 ; 
         FIG. 20  is front elevational view of the radial tooth of  FIG. 19 ; 
         FIG. 21  is a front and side perspective view of another embodiment of the disclosed trowel; 
         FIG. 22  is a front and side perspective view of another embodiment of the disclosed trowel; 
         FIG. 23  is a front and side perspective view of another embodiment of disclosed trowel; 
         FIG. 24  is a flow chart of one embodiment of the disclosed method for applying a layer of curable material to a surface; 
         FIG. 25  is flow diagram of an aircraft production and service methodology; and 
         FIG. 26  is a block diagram of an aircraft. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description refers to the accompanying drawings, which illustrate specific embodiments of the disclosure. Other embodiments having different structures and operations do not depart from the scope of the present disclosure. Like reference numerals may refer to the same element or component in the different drawings. 
     Referring to  FIG. 1 , one embodiment of the disclosed trowel, generally designated  10 , may include a main body  12  having at least one working edge  14 . A plurality of radial teeth  16  may be connected to, and may be axially aligned along, the working edge  14 . Each radial tooth  18  of the plurality of radial teeth  16  may extend radially outward from the working edge  14  of the main body  12  (e.g., having at least one radial edge projected from the working edge  14  of the main body  12 ). Each radial tooth  18  may be aligned with and spaced apart (e.g., equally spaced or variably spaced) from an adjacent radial tooth  18  to define a gap  20  therebetween. The radial teeth  18  may be solid disks of various configurations or solid spheres. Other shapes of the radial teeth  18  are also contemplated. 
     In one implementation, the radial teeth  18  may be fixedly connected to the main body  12  such that the radial teeth  18  are stationary. In another, optional implementation, the radial teeth  18  may be rotatably connected to the main body  12  such that the radial teeth  18  rotate about an axis. 
     The main body  12  may include a first surface  22 , a second surface  24  opposite the first surface, and a perimeter edge  26 . In an example construction, the first surface  22  and the second surface  24  may be substantially planar and the main body  12  may have a constant thickness. In another example construction, the first surface  22  and the second surface  24  may be contoured, for example having an ergonomic-assisting curvature that provides a comfortable grip, while the radial teeth  18  remain in a linear arrangement. For example, the thickness of the main body  12  at a central region may be greater than the thickness of the main body  12  proximate (e.g., at or near) one or more perimeter edge  26  to provide a more comfortable gripping surface. 
     Optionally, the main body  12  may include a handle (not shown) connected to at least one of the first surface  22  or the second surface  24 . 
     The main body  12  may have any shape and the perimeter edge  26  may have any geometric profile. In an example construction, as illustrated in  FIG. 1 , the main body  12  may have a generally rectangular shape and the perimeter edge  26  may include a first (e.g., upper) edge  26   a , a second (e.g., lower) edge  26   b , a third (e.g., left side) edge  26   c , and a fourth (e.g., right side) edge  26   d . The working edge  14  may be defined by one or more perimeter edges  26  (e.g., the second edge  26   b ) of the main body  12 . 
     In an example construction, the plurality of radial teeth  16  may extend along substantially all of the working edge  14  (e.g., along the second edge  26   b  from proximate the third edge  26   c  to proximate the fourth edge  26   d ). In another example construction, the plurality of radial teeth  16  may extend along a portion of the working edge  14 . 
     In an example construction, as illustrated in  FIG. 1 , at least one working edge  14  may be substantially straight for use of the trowel  10  to apply a constant thickness, uniform intermediate layer  30  of curable material  32  (e.g., adhesive or mortar, such as thinset) on a substantially planar surface  34 . Each radial tooth  18  of the plurality of radial teeth  16  on the straight working edge  14  may extend substantially perpendicular to a respective location of the working edge  14 . 
     In another example construction, at least one working edge  14  may be curved or include a contoured profile (not shown) for use of the trowel  10  to apply a constant thickness, uniform intermediate layer  30  of curable material  32  on a curved or contoured surface (not shown). Each radial tooth  18  of the plurality of radial teeth  16  on the contoured working edge  14  may extend substantially perpendicular to a respective location of the working edge  14 . 
     In another example construction, the main body  12  may include at least one straight working edge  14  and at least one curved or contoured working edge  14  (not shown) to apply a constant thickness, uniform intermediate layer  30  of curable material  32  on a straight surface  34  and a contoured surface (not shown). As will be described in greater detail herein (e.g.,  FIG. 18 ), the configuration of the plurality of radial teeth  16  on each working edge  14  may be the same or may be different. 
     As shown in  FIG. 2 , in an example embodiment, each radial tooth  18  may be substantially centered on the working edge  14  of the main body  12 . For example, the center of the working edge  14  may be aligned with the center of the radial tooth  18  such that the working edge  14  may be maintained at a constant spaced apart distance relative to a surface  34  ( FIG. 4 ) of a part irrespective of the angle of the trowel  10  with respect to the surface  34 . In an example construction, the working edge  14  may include a substantially semi-circular cross-sectional shape having an edge radius r relative to the center of the working edge  14 . Each radial tooth  18  of the plurality of radial teeth  16  ( FIG. 1 ) may include a substantially circular cross-sectional shape having a tooth radius R relative to the center of the radial tooth  18 . Thus, a straight-line distance D between the working edge  14  and a radial edge  28  of the radial tooth  18  (e.g., the tooth radius R minus the edge radius r) at any point along the working edge  12  may be substantially equal. 
     As shown in  FIG. 3 , in another example embodiment, each radial tooth  18  may be at least partially offset from the working edge  14  of the main body. For example, the center of the radial tooth  18  may be offset from the center of the working edge  14  such that the spaced apart distance between the working edge  14  relative to the surface  34  ( FIG. 4 ) of a part may vary depending upon the angle of the trowel  10  with respect to the surface  34 . 
     As shown in  FIGS. 4-7 , the disclosed trowel  10  may be used for the application of an intermediate layer  30  of curable material  32  (e.g., an adhesive) to the surface  34  of a part, such as a bonded surface of a bonded component. As also shown in  FIGS. 4-7 , the disclosed trowel  10  may also be used for spreading and/or thinning the curable material on the surface  34  of the part. The intermediate layer  30  of curable material  32  may, for example, be an adhesive layer, a waterproof layer, and/or a vapor barrier layer. After application of the intermediate layer  30  of curable material  32 , a surface of another part may be applied and bonded to the intermediate layer  30  of curable material  32  to form the bonded component. 
     In an example implementation, the curable material  32  (e.g., an adhesive) may be applied to the surface  34  at an initial thickness T i  (e.g., an applied thickness). As illustrated in  FIG. 4 , the disclosed trowel  10  may be moved across the surface  34 , such as in the direction indicated by directional arrow  36 , to spread and level the curable material  32  and form the intermediate layer  30 . The trowel  10  may be configured to maintain a constant thickness t of the intermediate layer  30  (e.g., as the curable material  32  is spread over the surface  34 ) irrespective of the angle of the trowel  10  with respect to the surface  34  to which the curable material  32  is applied. 
     The trowel  10  may be pushed along the surface  34  (e.g.,  FIG. 6 ) or dragged across the surface  34  (e.g.,  FIG. 7 ) at relatively any non-zero angle with respect to the surface  34  to spread and level the curable material  32 . For example, as illustrated in  FIG. 5 , the trowel  10  may be positioned at a first angle θ 1  (e.g., approximately 90°) with respect to the surface  34 . As the trowel  10  is moved across the surface  34  (e.g., in the direction of arrow  36 ), the intermediate layer  30  may have the constant thickness T. As another example, as illustrated in  FIG. 6 , the trowel  10  may be positioned at a second angle θ 2  (e.g., approximately 45°) with respect to the surface  34 . As the trowel  10  is pushed across the surface  34  (e.g., in the direction of arrow  36 ), the intermediate layer  30  may have the constant thickness T. As yet another example, as illustrated in  FIG. 7 , the trowel  10  may be positioned at a third angle θ 3  (e.g., approximately 120°) with respect to the surface  34 . As the trowel  10  is drug across the surface  34  (e.g., in the direction of arrow  36 ), the intermediate layer  30  may have the constant thickness T. 
     Thus, the position (e.g., angle) of the trowel  10  with respect to the surface  34  may change or vary throughout the movement of the trowel  10  across the surface  34  without affecting the thickness t of the intermediate layer  32 . 
     As will be described in more detail herein below, each radial tooth  18  of the plurality of radial teeth  16  may include at least one radial edge. For example, the radial edge may extend circumferentially. As another example, the radial edge may include a constant curve. As yet another example, the radial edge may include at least two flat segments that intersect. 
     Referring to  FIGS. 8-15 , each radial tooth  18  of the plurality of radial teeth  16  ( FIG. 1 ) may include a generally disk-shaped tooth body  40  having a circular cross-sectional shape (e.g., having a circumferential radial edge  28 ) and the tooth radius R. The tooth body  30  may include a first side  44 , a second side  46  opposite the first side  44 , and a substantially circular radial edge  28 . The tooth body  40  may include a thickness t 1 . The radial edge  28  may include a thickness t 2 . At least a portion of a peripheral surface  42  of the tooth body  40  (e.g., the radial edge  28 ) may contact the surface  34  as the trowel  10  is moved across the surface  34  to spread and level the curable material  32  ( FIG. 4 ). 
     As illustrated in  FIGS. 8 and 9 , an example embodiment of the radial tooth  18  may include substantially planar first  44  and second  46  sides. The radial edge  28  may be substantially flat from the first side  44  to the second side  46  (e.g., the peripheral surface  42  may be perpendicular to the first  44  and second sides  46 ) such that the thickness t 2  of the radial edge  28  (e.g., the portion of the circumferential surface  42  in contact with the surface  34 ) is substantially equal to the thickness t 1  of the tooth body  40 . 
     As illustrated in  FIGS. 10 and 11 , another example embodiment of the radial tooth  18  may include substantially planar first  44  and second  46  sides. The peripheral surface  42  may be rounded outwardly from the first side  44  to the second side  46  such that the thickness t 2  of the radial edge  28  (e.g., the portion of the peripheral surface  42  in contact with the surface  34 ) is less than the thickness t 1  of the tooth body  40 . 
     As illustrated in  FIGS. 12 and 13 , another example embodiment of the radial tooth  18  may include inwardly tapered first  44  and second  46  sides (e.g., the first  44  and second  46  sides may be disposed at an inwardly disposed angle from proximate the center of the tooth body  40  to proximate the radial edge  28 ). The radial edge  42  may be substantially flat from the first side  44  to the second side  46  (e.g., the peripheral surface  42  may be perpendicular to the first  44  and second sides  46 ) such that the thickness t 2  of the radial edge  28  (e.g., the portion of the peripheral surface  42  in contact with the surface  34 ) is substantially less than the thickness t 1  of the tooth body  40 . 
     As illustrated in  FIGS. 14 and 15 , another example embodiment of the radial tooth  18  may include substantially planar first  44  and second  46  sides. The peripheral surface  42  may be disposed at a non-perpendicular angle relative the first  44  and second  46  sides such that the peripheral surface  42  terminates at a point and the thickness t 2  of the radial edge  28  (e.g., the portion of the peripheral surface  42  in contact with the surface  34 ) is substantially less than the thickness t 1  of the tooth body  40 . 
     Referring to  FIGS. 16 and 17 , another embodiment of the disclosed trowel  10  may include the plurality of radial teeth  16  connected to the working edge  14  of the main body  12 . Each radial tooth  18  may be aligned with and spaced apart from an adjacent radial tooth  18  to define a gap  20  therebetween. Each radial tooth  18  of the plurality of radial teeth  16  may include a generally spherical tooth body  40  having a circular cross-sectional shape (e.g., having a radial edge extending circumferentially) and the tooth radius R. The tooth body  40  may include a thickness t 1  (e.g., a diameter of the tooth body  40 ). The radial edge  28  of the tooth body  40  may include a thickness t 2 . At least a portion of a peripheral surface  42  of each tooth body  42  (e.g., the radial edge  28 ) may contact the surface  34  as the trowel  10  is moved across the surface  34  to spread and level the curable material  32  ( FIG. 4 ). 
     Referring to  FIGS. 18-20 , another embodiment of the disclosed trowel  10  may include the plurality of radial teeth  16  connected to the working edge  14  of the main body  12 . Each radial tooth  18  of the plurality of radial teeth  16  may include a tooth body  60  having a generally rectilinear shape (e.g., having a radial edge defined by at least two flat surfaces that intersect). Each radial tooth  18  may be aligned with and spaced apart from an adjacent radial tooth  18  to define a gap  20  therebetween. The tooth body  60  may include a plurality of tooth faces  62  (e.g., sides) defining a peripheral surface  68  of the radial tooth  18 . In an example construction, the tooth body  60  may include at least four (4) tooth faces  62 . In an example construction, the tooth body  60  may include at least five (5) tooth faces  62 . In another example construction, the tooth body may include at least six (6) tooth faces  62 . In another example embodiment, the tooth body may include at least eight (8) tooth faces  62 . In yet another example embodiment, the tooth body may include more than eight (8) tooth faces. 
     The tooth body  60  may include a width   defined by the distance from the center of the tooth body  60  to the tooth face  62  (e.g., to the midpoint of the tooth face  62 ). The tooth body  60  may include a thickness t 1  (e.g., a thickness of the tooth body  60 ). A radial edge  70  of the tooth body  60  may include a thickness t 2 . At least a portion of the peripheral surface  68  of each tooth body  60  (e.g., the radial edge  70  of at least one tooth face  62 ) may contact the surface  34  as the trowel  10  is moved across the surface  34  to spread and level the curable material  32  ( FIG. 4 ). The tooth faces  62  (e.g., sections of the substantially flat peripheral surface  68 ) may be arranged such that the trowel  10  may be positioned at a particular non-zero angle with respect to the surface  34  when a particular tooth face  62  is in contact with (e.g., flat against) the application surface  34 . In an example construction, the main body  12  and the working edge  14  may be configured such that the distance from the working edge  14  to any one particular tooth face  62  (e.g., to the midpoint of the tooth face  62 ) defines a thickness T of the curable material  32  as the curable material  32  is spread and leveled ( FIG. 4 ). 
     The tooth body  60  may include substantially planar first  64  and second  66  sides. In an example construction, each tooth face  62  may be substantially flat from the first side  64  to the second side  66  (e.g., the peripheral surface  68  may be substantially perpendicular to the first  64  and second sides  66 ) such that the thickness t 2  of the radial edge  70  (e.g., the portion of the tooth face  62  in contact with the surface  34 ) is substantially equal to the thickness t 1  of the tooth body  60 . 
     In another example construction, each tooth face  62  may be disposed at a non-perpendicular angle relative the first  64  and second  66  sides such that the peripheral surface  68  terminates at a point (not shown) and the thickness t 2  of the radial edge  70  (e.g., the portion of the tooth face  62  in contact with the surface  34 ) is substantially less than the thickness t 1  of the tooth body  60 . 
     Referring to  FIG. 21 , another embodiment of the disclosed trowel  10  may include the plurality of radial teeth  16  connected to the working edge  14  of the main body  12 . Each radial tooth  18  of the plurality of radial teeth  16  may include a generally semi-circular tooth body  80  (e.g., having a radial defined by a constant curve). Each radial tooth  18  may be aligned with and spaced apart from an adjacent radial tooth  18  to define a gap  20  therebetween. The tooth body  80  may include a first side, a second side opposite the first side, a semi-circular peripheral surface, and a radial edge  82 . For example, the radial edge  82  may extend approximately 180 degrees (e.g., a half circle). As another example, the radial edge  82  may extend approximately 270 degrees (e.g., a three-quarters circle). 
     Each tooth body  80  may include a tooth radius (e.g., from the center of the tooth body  80  to the radial edge  82 ), a tooth body thickness, and a radial edge thickness (e.g., a portion of a peripheral surface that may contact the surface  34 ), as described above. Further, each tooth body  80  may include various configurations, as described above and illustrated in  FIGS. 8-15 . 
     Referring to  FIG. 22 , in another example embodiment, every other semi-circular radial tooth  18  may be rotated (e.g., by 90 degrees) with respect to an adjacent radial tooth  18  such that at least a portion of a circumferential surface (e.g., the radial edge  82 ) of at least one tooth body  80  may contact the surface  34  as the trowel  10  is moved across the surface  34  to spread and level the curable material  32  ( FIG. 4 ). Thus, the position (e.g., angle) of the trowel  10  with respect to the surface  34  may change or vary throughout the movement of the trowel  10  across the surface  34  without affecting the thickness t of the intermediate layer  32  ( FIG. 4 ). 
     Other shapes and configurations of the radial teeth  18  are also contemplated. 
     Referring to  FIG. 23 , another embodiment of the disclosed trowel  10  may include the main body  12  having a plurality of working edges  14 . A plurality of radial teeth  16  may be connected to each working edge  14  of the plurality of working edges  14 . In an example construction, the main body  12  may have a generally rectangular shape and the perimeter edge  26  may include a first (e.g., upper) edge  26   a , a second (e.g., lower) edge  26   b , a third (e.g., left side) edge  26   c , and a fourth (e.g., right side) edge  26   d . A first working edge  14   a  may be defined by the first edge  26   a , a second working edge  14   b  may be defined by the second edge  26   b , a third working edge  14   c  may be defined by the third edge  26   c , and a fourth working edge  14   d  may be defined by the fourth edge  26   d . A first plurality of radial teeth  16   a  may extend along substantially the entire first working edge  14   a  (e.g., along the first edge  26   a  from proximate the third edge  26   c  to proximate the fourth edge  26   d ). A second plurality of radial teeth  16   b  may extend along substantially the entire second working edge  14   b  (e.g., along the second edge  26   b  from proximate the third edge  26   c  to proximate the fourth edge  26   d ). A third plurality of radial teeth  16   c  may extend along substantially the entire third working edge  14   c  (e.g., along the third edge  26   c  from proximate the first edge  26   a  to proximate the second edge  26   b ). A fourth plurality of radial teeth  16   d  may extend along substantially the entire fourth working edge  14   d  (e.g., along the fourth edge  26   d  from proximate the first edge  26   a  to proximate the second edge  26   b ). 
     The configuration of each plurality of radial teeth  16   a ,  16   b ,  16   c ,  16   d  on each working edge  14   a ,  14   b ,  14   c ,  14   d  may be different depending upon the application requirements of a specific curable material  32  and/or the constraints of the surface  34 . For example, each plurality of radial teeth  16   a ,  16   b ,  16   c ,  16   d  may include different size, shape, and/or configuration of tooth body  40 ,  60 ,  80 . As another example, each plurality of radial teeth  16   a ,  16   b ,  16   c ,  16   d  may include a different tooth radius R ( FIG. 2 ). As another example, each plurality of radial teeth  16   a ,  16   b ,  16   c ,  16   d  may include a different thickness t 1  of the tooth body  40 . As another example, the each plurality of radial teeth  16   a ,  16   b ,  16   c ,  16   d  may include a different thickness t 2  of the radial edge  28 . As yet another example, each radial tooth  18  of each plurality of radial teeth  16   a ,  16   b ,  16   c ,  16   d  may be spaced apart from an adjacent radial tooth  18  at a different distance (e.g., the gap  20  between adjacent radial teeth  18  may be different for each plurality of radial teeth  16   a ,  16   b ,  16   c ,  16   d ). 
     Referring again to  FIG. 4 , those skilled in the art will appreciate that various characteristics of the intermediate layer  30  of curable material  32  (e.g., adhesive) may depend upon the configuration of the plurality of radial teeth  16  and the configuration of each radial tooth  18 . For example, the thickness T of the intermediate layer  30  may depend upon the distance D between the working edge  14  and a radial edge  28  of the radial tooth  18  (e.g., the tooth radius R minus the edge radius r) ( FIG. 2 ). As another example, the width w of each line (or strip)  38  of curable material  32  may depend upon the size of the gap  20  (e.g., the distance between adjacent radial teeth  18 ). As another example, the distance d between adjacent lines  38  of curable material  32  may depend upon the thickness t 1  of the tooth body  40  and/or the thickness t 2  of the radial edge  28  ( FIGS. 8, 10, 12, 14, and 17 ). As yet another example, the shape and/or profile of the lines  38  of curable material  32  may depend upon the shape of the tooth body  40 . 
     The type and/or configuration of the plurality of radial teeth  16  may be selected based on the surface  34  upon which the curable material  32  (e.g., adhesive) is spread (e.g., disk-shaped tooth body  40  on metal surfaces and spherical-shaped tooth body  40  on composite or plastic surfaces). Further the spacing between radial teeth  18  and/or the size and/or shape of the radial teeth  18  may be customized for different characteristics (e.g., thicknesses T) of the intermediate layer  30  of curable material  32 , for how much curable material  32  is to be used, and/or the type of components being bonded together. 
     Thus, during use of the disclosed trowel  10 , different working edges  14  having different configurations of the plurality of radial teeth  16  may be used as needed based on a specific job requirement and/or surface constraint. For example, when different thicknesses T of an intermediate layer  30  of curable material  32  (e.g., adhesive) are to be applied to one or more surfaces  32  by the same operator, the first working edge  14   a  (e.g., including the first plurality of radial teeth  16   a  having a first size and/or shape) may be used on a first surface and the second working edge  14   b  (e.g., including the second plurality of radial teeth  16   b  having a second size and/or shape) may be used on a second surface. This may allow the operator to simply rotate the trowel  10  to apply different characteristics (e.g., thicknesses T) of the intermediate layer  30  without changing trowels. 
     Optionally, the main body  12  may include a beveled or chamfered edge  50  ( FIG. 23 ) proximate one or more perimeter edge  26 . The chamfered edge  50  may be configured to reduce the edge radius r ( FIG. 2 ) and minimize the surface area of the main body  12  that may come into contact with the curable material  32  during leveling of the intermediate layer  30  ( FIG. 3 ). 
     The disclosed trowel  10  may be fabricated having any configuration of working edges  14  and/or plurality of radial teeth  16  based on the various requirements and/or constraints of the application process. For example, the trowel  10  may be 3D printed, injection molded, or otherwise formed as one piece. Alternatively, the plurality of radial teeth  16  may be coupled to the working edge  14  of the main body  12 . 
     Referring now to  FIG. 24 , also disclosed is one embodiment of the disclosed method, generally designated  100 , for uniformly applying an intermediate layer of curable material to a surface. As shown at block  102 , a part may be provided having a surface that will be bonded to a second surface. As shown at block  104 , an initial amount of curable material (e.g., adhesive; mortar) may be applied to the surface. The initial amount of curable material may have an initial thickness T i  ( FIG. 3 ). As shown at block  106 , a trowel including at least one working edge and a plurality of radial teeth  16  connected to the working edge may be provided. As shown at block  108 , the trowel may be positioned at any non-zero angle with respect to the surface. As shown at block  110 , the trowel may be moved (e.g., pushed and/or dragged) across the surface to spread and level the initial amount of curable material. As shown at block  112 , a uniform intermediate layer of curable material having a constant thickness may be formed. 
     Examples of the disclosure may be described in the context of an aircraft manufacturing and service method  200 , as shown in  FIG. 25 , and an aircraft  202 , as shown in  FIG. 20 . During pre-production, the aircraft manufacturing and service method  200  may include specification and design  204  of the aircraft  202  and material procurement  206 . During production, component/subassembly manufacturing  208  and system integration  210  of the aircraft  202  takes place. Thereafter, the aircraft  202  may go through certification and delivery  212  in order to be placed in service  214 . While in service by a customer, the aircraft  202  is scheduled for routine maintenance and service  216 , which may also include modification, reconfiguration, refurbishment and the like. 
     Each of the processes of method  200  may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of venders, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on. 
     As shown in  FIG. 26 , the aircraft  202  produced by example method  200  may include an airframe  218  with a plurality of systems  220  and an interior  222 . Examples of high-level systems  220  include one or more of a propulsion system  224 , an electrical system  226 , a hydraulic system  228 , and an environmental system  230 . Any number of other systems may be included. Although an aerospace example is shown, the principles of the invention may be applied to other industries, such as the automotive industry. 
     Apparatus and methods embodied herein may be employed during any one or more of the stages of the production and service method  200 . As one example, components or subassemblies corresponding to component/subassembly manufacturing  208  may be fabricated or manufactured using the disclosed trowel  10  ( FIG. 1 ). The fabrication during component/subassembly manufacturing  208  may relate to the airframe  218  and/or the interior  222  of the aircraft  202 . As another example, system integration  210  may be performed using the disclosed trowel  10 . As yet another example, maintenance and service  216  may be performed using the disclosed trowel  10 . Use of the disclosed trowel  10  may substantially expedite assembly and/or may reduce the cost of the aircraft  202 . 
     Although various embodiments of the disclosed trowel have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.