Patent Publication Number: US-11027461-B2

Title: Apparatus for applying materials over fastener heads protruding from non-horizontal surfaces

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. application Ser. No. 15/469,784, entitled “METHODS OF APPLYING MATERIALS OVER FASTENER HEADS PROTRUDING FROM NON-HORIZONTAL SURFACES,” filed on 27 Mar. 2017 which is incorporated herein by reference in its entirety for all purposes. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to apparatuses and methods for applying materials over fastener heads protruding from non-horizontal surfaces of parts. 
     BACKGROUND 
     When materials, such as adhesives, sealants, paints, potting materials, and the like, are applied over fastener heads protruding from non-horizontal surfaces of parts, these materials may sag due to gravity before the materials are cured. Yet, not all parts can be positioned such that their surfaces and protruding fastener heads are horizontal to avoid the effects of gravity. 
     SUMMARY 
     Accordingly, apparatuses and methods, intended to address at least the above-identified concerns, would find utility. 
     The following is a non-exhaustive list of examples, which may or may not be claimed, of the subject matter according to the invention. 
     One example of the subject matter according to the invention relates to an applicator for applying a material over a fastener head, protruding from a non-horizontal surface of a part. The applicator comprises an enclosure, a daubing lever, and means for imparting a moment on the daubing lever. The enclosure comprises a wall, comprising an inner side. The wall also comprises an interior surface on the inner side and an outer side, opposite the inner side. The enclosure further comprises an interior space, defined by the interior surface of the wall. The daubing lever passes through the wall of the enclosure and is movably coupled to the enclosure. The daubing lever comprises an actuation end, located on the outer side of the wall of the enclosure. The daubing lever also comprises a working end, located opposite the actuation end on the inner side of the wall of the enclosure. Furthermore, the daubing lever comprises an abutment portion, located at one of the actuation end, the working end, or between the actuation end and the working end. The means for imparting the moment on the daubing lever bias the abutment portion of the daubing lever toward the enclosure. 
     Another example of the subject matter according to the invention relates to a method of applying a material onto a fastener head, protruding from a non-horizontal surface of a part. The material is applied using an applicator comprising an enclosure, a daubing lever, extending within an interior space of the enclosure, and means for imparting a moment on the daubing lever to bias an abutment portion of the daubing lever toward the enclosure. The method comprises advancing the applicator toward the non-horizontal surface of the part along an axis that is perpendicular to the non-horizontal surface. The applicator is advanced to establish contact between a working end of the daubing lever and the fastener head and to cause the abutment portion of the daubing lever to move away from the enclosure. The method further comprises pressing a sealing rim of the enclosure against the non-horizontal surface of the part around the fastener head. The method also comprises at least partially filling the enclosure with the material. The method additionally comprises retracting the applicator away from the non-horizontal surface along the axis perpendicular to the non-horizontal surface while maintaining contact between the working end of the daubing lever and the fastener head to enable the means for imparting the moment on the daubing lever to cause the working end of the daubing lever to move relative to the enclosure across the fastener head and to asymmetrically distribute the material, at least partially filling the enclosure, across the fastener head such that more of the material is located along a top half of the fastener head then along a bottom half of the fastener head. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Having thus described one or more examples of the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein like reference characters designate the same or similar parts throughout the several views, and wherein: 
         FIG. 1  is a block diagram of an applicator assembly comprising an applicator, according to one or more examples of the present disclosure; 
         FIG. 2A  is a schematic, side, cross-sectional view of the applicator of  FIG. 1 , according to one or more examples of the present disclosure; 
         FIG. 2B  is a schematic, side, cross-sectional view of the applicator of  FIG. 1  showing material filling the interior space of the enclosure of the applicator, according to one or more examples of the present disclosure; 
         FIG. 2C  is a schematic, bottom view of an enclosure of the applicator of  FIG. 1 , according to one or more examples of the present disclosure; 
         FIG. 2D  is a schematic, side, cross-sectional view of the applicator of  FIG. 1  showing a circular through opening, according to one or more examples of the present disclosure; 
         FIG. 3  is a block diagram of a method of applying material onto a fastener head utilizing the applicator of  FIG. 1 , according to one or more examples of the present disclosure; 
         FIGS. 4A-4J  are schematic, side, cross-sectional views of the applicator of  FIG. 1  at different stages of the method of  FIG. 3 , according to one or more examples of the present disclosure; 
         FIGS. 5A-5E  are schematic, perspective, cross-sectional views of the applicator of  FIG. 1 , according to one or more examples of the present disclosure; 
         FIGS. 6A-6D  are schematic, side views of the daubing lever of the applicator of  FIG. 1 , according to one or more examples of the present disclosure; 
         FIG. 7  is a block diagram of aircraft production and service methodology; and 
         FIG. 8  is a schematic illustration of an aircraft. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1 , referred to above, solid lines, if any, connecting various elements and/or components may represent mechanical, electrical, fluid, optical, electromagnetic and other couplings and/or combinations thereof. As used herein, “coupled” means associated directly as well as indirectly. For example, a member A may be directly associated with a member B, or may be indirectly associated therewith, e.g., via another member C. It will be understood that not all relationships among the various disclosed elements are necessarily represented. Accordingly, couplings other than those depicted in the block diagrams may also exist. Dashed lines, if any, connecting blocks designating the various elements and/or components represent couplings similar in function and purpose to those represented by solid lines; however, couplings represented by the dashed lines may either be selectively provided or may relate to alternative examples of the present disclosure. Likewise, elements and/or components, if any, represented with dashed lines, indicate alternative examples of the present disclosure. One or more elements shown in solid and/or dashed lines may be omitted from a particular example without departing from the scope of the present disclosure. Environmental elements, if any, are represented with dotted lines. Virtual (imaginary) elements may also be shown for clarity. Those skilled in the art will appreciate that some of the features illustrated in  FIG. 1  may be combined in various ways without the need to include other features described in  FIG. 1 , other drawing figures, and/or the accompanying disclosure, even though such combination or combinations are not explicitly illustrated herein. Similarly, additional features not limited to the examples presented, may be combined with some or all of the features shown and described herein. 
     In  FIGS. 7 and 8 , referred to above, the blocks may represent operations and/or portions thereof and lines connecting the various blocks do not imply any particular order or dependency of the operations or portions thereof. Blocks represented by dashed lines indicate alternative operations and/or portions thereof. Dashed lines, if any, connecting the various blocks represent alternative dependencies of the operations or portions thereof. It will be understood that not all dependencies among the various disclosed operations are necessarily represented.  FIGS. 7 and 8  and the accompanying disclosure describing the operations of the method(s) set forth herein should not be interpreted as necessarily determining a sequence in which the operations are to be performed. Rather, although one illustrative order is indicated, it is to be understood that the sequence of the operations may be modified when appropriate. Accordingly, certain operations may be performed in a different order or simultaneously. Additionally, those skilled in the art will appreciate that not all operations described need be performed. 
     In the following description, numerous specific details are set forth to provide a thorough understanding of the disclosed concepts, which may be practiced without some or all of these particulars. In other instances, details of known devices and/or processes have been omitted to avoid unnecessarily obscuring the disclosure. While some concepts will be described in conjunction with specific examples, it will be understood that these examples are not intended to be limiting. 
     Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, e.g., a “second” item does not require or preclude the existence of, e.g., a “first” or lower-numbered item, and/or, e.g., a “third” or higher-numbered item. 
     Reference herein to “one example” means that one or more feature, structure, or characteristic described in connection with the example is included in at least one implementation. The phrase “one example” in various places in the specification may or may not be referring to the same example. 
     As used herein, a system, apparatus, structure, article, element, component, or hardware “configured to” perform a specified function is indeed capable of performing the specified function without any alteration, rather than merely having potential to perform the specified function after further modification. In other words, the system, apparatus, structure, article, element, component, or hardware “configured to” perform a specified function is specifically selected, created, implemented, utilized, programmed, and/or designed for the purpose of performing the specified function. As used herein, “configured to” denotes existing characteristics of a system, apparatus, structure, article, element, component, or hardware which enable the system, apparatus, structure, article, element, component, or hardware to perform the specified function without further modification. For purposes of this disclosure, a system, apparatus, structure, article, element, component, or hardware described as being “configured to” perform a particular function may additionally or alternatively be described as being “adapted to” and/or as being “operative to” perform that function. 
     Illustrative, non-exhaustive examples, which may or may not be claimed, of the subject matter according the present disclosure are provided below. 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 2A and 2B , applicator  200  for applying material  104  over fastener head  112 , protruding from non-horizontal surface  116  of part  114 , is disclosed. Applicator  200  comprises enclosure  210 , daubing lever  220 , and means  240  for imparting a moment on daubing lever  220 . Enclosure  210  comprises wall  213 , which in turn comprises inner side  214 , interior surface  215  on inner side  214 , and outer side  216 , opposite inner side  214 . Enclosure  210  further comprises interior space  211 , defined by interior surface  215  of wall  213 . Daubing lever  220  passes through wall  213  of enclosure  210  and is movably coupled to enclosure  210 . Daubing lever  220  comprises actuation end  222   a , located on outer side  216  of wall  213  of enclosure  210 . Daubing lever  220  also comprises working end  222   b , located opposite actuation end  222   a  on inner side  214  of wall  213  of enclosure  210 . Daubing lever  220  further comprises abutment portion  228 , located at one of actuation end  222   a , working end  222   b , or between actuation end  222   a  and working end  222   b . Means  240  impart the moment on daubing lever  220  to bias abutment portion  228  of daubing lever  220  toward enclosure  210 . The preceding subject matter of this paragraph characterizes example 1 of the present disclosure. 
     Working end  222   b  is configured to contact fastener head  112  as enclosure  210  is moved toward or away from non-horizontal surface  116  of part  114 . This contact is ensured by the moment imparted on daubing lever  220  by means  240 . This moment moves daubing lever  220  relative to enclosure  210  and maintains the contact between working end  222   b  and fastener head  112  as enclosure  210  is moved relative to non-horizontal surface  116 . It should be noted that working end  222   b  moves relative to fastener head  112  while maintaining the contact. When enclosure  210  is retracted from non-horizontal surface  116  and after material  104  is applied to fastener head  112 , working end  222   b  redistributes material  104  on fastener head  112 . Specifically, material  104  may be swiped in the direction opposite of the gravitation force resulting in uneven distribution of material  104  on fastener head  112  when working end  222   b  eventually retracts from fastener head  112 . This uneven distribution is designed to compensate for gravitational sagging that occurs later and while material  104  cures on fastener head  112 . When material  104  is cured and material  104  does not sag anymore, the distribution of material  104  on fastener head  112  can be uniform. 
     Means  240  impart the moment on daubing lever  220  and may cause daubing lever  220  to move relative to enclosure until abutment portion  228  contacts enclosure  210  (as, e.g., shown in  FIG. 2A ) or working end  222   b  contacts fastener head  112  (as, e.g., shown in  FIG. 2B ). The moment is sufficient to move daubing lever  220  through material  104  in the enclosure. Various features of daubing lever  220 , further described below, may assist with this movement through material  104 . Material  104  may be a viscous substance (e.g., a viscosity of at least about 1,000 cP or even at least about 10,000 cP). 
     Furthermore, means  240  may be designed to provide enough moment for this motion to occur. Some example of means  240  for imparting a moment on daubing lever  220  are a rubber band, a spring, and a pneumatic device. For example, a rubber band may be placed around enclosure  210  and around actuation end  222   a  of daubing lever  220 , as for example, shown in  FIGS. 2A and 2B . The rubber band may pull actuation end  222   a  toward enclosure  210 , which imparts the moment on daubing lever  220  to bias abutment portion  228  of daubing lever  220  toward enclosure  210 . 
     Abutment portion  228  may be pulled away from enclosure  210  when working end  222   b  contacts fastener head  112  and counters the moment imparted by means  240 . In this situation, while the moment continues to bias abutment portion  228  toward enclosure  210 , it also biases working end  222   b  toward fastener head  112  such that working end  222   b  maintains contact with fastener head  112  until abutment portion  228  contacts enclosure  210 . Furthermore, working end  222   b  continues to maintain the contact with fastener head  112  as enclosure  210  is being moved toward (see, e.g.,  FIGS. 4B-4D ) and away (see, e.g.,  FIGS. 4E-4G ) from non-horizontal surface  116  of part  114 . This continuous contact between working end  222   b  and fastener head  112  causes redistribution of material  104  on fastener head  112 , after material  104  is deposited into fastener head  112 , and as enclosure  210  is being moved away from non-horizontal surface  116  of part  114 . Specifically, this redistribution may be in the direction opposite of the gravitation force thereby allowing to compensate for gravitational sagging while material  104  cures. 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 2A-2C , enclosure  210  comprises sealing rim  212  that lies in virtual plane  204 . The preceding subject matter of this paragraph characterizes example 2 of the present disclosure, wherein example 2 also includes the subject matter according to example 1, above. 
     Sealing rim  212  is used to seal enclosure  210  relative to non-horizontal surface  116  of part  114  thereby restricting material  104  to sealed portion  117  of non-horizontal surface  116  and preventing undesired contamination of part  114  beyond sealed portion  117  as, for example, schematically shown in  FIG. 2B . 
     When sealing rim  212  contacts non-horizontal surface  116  of part  114 , material  104  flows within interior space  211  of enclosure  210  toward non-horizontal surface  116  of part  114  and fastener head  112 . This flows deposits material  104  into fastener head  112  and a portion of non-horizontal surface  116  around fastener head  112 . Sealing rim  212  blocks the flow of material  104  beyond sealed portion  117 . As such, sealing rim  212  defines the shape and size of sealed portion  117 . The flow of material  104  within interior space  211  of enclosure  210  is stopped before sealing rim  212  is moved away from non-horizontal surface  116  of part  114 . Sealing rim  212  lies in virtual plane  204 , which may be perpendicular to center axis  202  of applicator  200 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIG. 2C , sealing rim  212  of enclosure  210  has a circular shape. The preceding subject matter of this paragraph characterizes example 3 of the present disclosure, wherein example 3 also includes the subject matter according to example 2, above. 
     Sealing rim  212  may be circular to accommodate fastener head  112  that is also circular. Sealing rim  212  defines sealed portion  117 , which is a boundary of material  104  on non-horizontal surface  116 . The circular boundary of material  104  does not have corners and has the minimal perimeter for a given boundary area, which may be useful for some applications. 
     The shape of sealing rim  212  defines shape of sealed portion  117  on non-horizontal surface  116 , which, in turn, may depend on the shape of fastener head  112 . In some examples, the shape of sealed portion  117  corresponds to the shape of fastener head  112  with sealed portion  117  being larger than the interface of fastener head  112  with non-horizontal surface  116 . This size difference defines the size of a sealing bead formed at the interface between fastener head  112  and non-horizontal surface  116 . The shape of sealing rim  212  as well as the alignment between sealing rim  212  and fastener head  112  during operation of applicator  200  ensures that the size of this sealing bead is uniform and proper sealing is achieved. 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 2A and 2B , daubing lever  220  is rotatable relative to enclosure  210 . The preceding subject matter of this paragraph characterizes example 4 of the present disclosure, wherein example 4 also includes the subject matter according to any one of examples 1 to 3, above. 
     Daubing lever  220  may rotate relative to enclosure  210  to allow movement of working end  222   b  relative to enclosure  210  and, more specifically, to maintain the contact with fastener head  112  while enclosure  210  moves away from non-horizontal surface  116  of part  114 . This contact with fastener head  112  allows working end  222   b  to redistribute material  104  previously applied to fastener head  112 . 
     The rotation of daubing lever  220  relative to enclosure  210  may be a result of the moment imparted by means  240 . The rotation may continue while enclosure  210  moves relative to non-horizontal surface  116  of part  114  and until abutment portion  228  of daubing lever  220  reaches enclosure  210 . The rotation may be in both direction: in one direction while enclosure  210  moves toward non-horizontal surface  116  of part  114  and in the other direction while enclosure  210  moves away non-horizontal surface  116 . When enclosure  210  is sealed against non-horizontal surface  116  of part  114  and does not move, working end  222   b  contacts fastener head  112  and daubing lever  220  does not rotate relative to enclosure  210 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 2A, 2B, and 2C and 6A-6D , daubing lever  220  comprises through opening  225 . Applicator further comprises shank  230 , fixed to enclosure  210  and protruding through opening  225  of daubing lever  220 . The preceding subject matter of this paragraph characterizes example 5 of the present disclosure, wherein example 5 also includes the subject matter according to example 4, above. 
     A combination of through opening  225  and shank  230  allows daubing lever  220  at least to rotate relative to enclosure  210  and, in some examples, to translate relative to enclosure  210  or, more specifically, relatively to shank  230 . Shank  230  is effectively a pivot point for rotation of daubing lever  220  relative to enclosure  210 . Shank  230  is also a retention for daubing lever  220  that restricts other types of movement of daubing lever  220 . 
     Shank  230  may have a cylindrical shape. Shank  230  may protrude between two edges of enclosure  210 . These edges may support shank  230 . Shank  230  may also support daubing lever  220 . A combination of through opening  225  and shank  230  controls the motion of daubing lever  220  relative to daubing lever  220 . For example, if both through opening  225  and shank  230  are circular (as, e.g., shown in  FIG. 2D ), then daubing lever  220  can only rotate relative to enclosure  210  around the center axis of through opening  225  and shank  230 . However, if through opening  225  is a slot, then daubing lever  220  can also translate relative to enclosure  210 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 2D and 6A , through opening  225  of daubing lever  220  is circular. The preceding subject matter of this paragraph characterizes example 6 of the present disclosure, wherein example 6 also includes the subject matter according to example 5, above. 
     Through opening  225  may be circular, which allows daubing lever  220  to rotate relative to enclosure  210 . Furthermore, when through opening  225  is circular, daubing lever  220  cannot translate relative to enclosure  210 . 
     Restricting movement of daubing lever  220  relative to enclosure  210  may simplify operations of applicator  200 . Furthermore, this feature may be used for fastener head  112  with a planar top surface. The length of a portion of daubing lever  220  extending between working end  222   b  and through opening  225  may be selected, at least in part, based on the diameter of fastener head  112 . Another factor in selecting the length of this portion may be the thickness of fastener head  112 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 2A, 2B, 6C, and 6D  through opening  225  of daubing lever  220  is a curved slot. The preceding subject matter of this paragraph characterizes example 7 of the present disclosure, wherein example 7 also includes the subject matter according to example 5, above. 
     When through opening  225  is a slot, daubing lever  220  may rotate and translate relative to enclosure  210 . While daubing lever  220  may rotate relative to enclosure  210  at any time, the curvature of through opening  225  may control at which point (e.g., an angle of daubing lever  220  relative to enclosure  210 ), daubing lever  220  may start translating relative to enclosure  210 . This translating feature may be used to accommodate fastener head  112  having a complex shape (e.g., a semi-spherical shape). 
     The curvature of through opening  225  may be specifically designed to accommodate particular shapes of fastener head  112 . For example, a semi-circular shape of fastener head  112  may need for daubing lever  220  to both translate and rotate relative to enclosure  210 . The combination of these features and the timing (provided by the curvature) ensures that working end  222   b  of daubing lever  220  stays in contact with fastener head  112  as working end  222   b  radially moves across fastener head  112  while swiping material  104  deposited on fastener head  112 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIG. 6B , through opening  225  of daubing lever  220  is straight slot. The preceding subject matter of this paragraph characterizes example 8 of the present disclosure, wherein example 8 also includes the subject matter according to example 5, above. 
     When through opening  225  is a straight slot, daubing lever  220  may be also able to translate relative to enclosure  210  in addition to being able to rotate relative to enclosure  210 . With through opening  225  being a straight slot, daubing lever  220  may translate relative to enclosure  210  at any time. Likewise, daubing lever  220  may rotate relative to enclosure  210  at any time. 
     With through opening  225  being a straight slot, daubing lever  220  may have more movement flexibility since daubing lever  220  can rotate and translate relative to enclosure  210  at any time than, for example, other examples described above. With this additional flexibility, working end  222   b  of daubing lever  220  may accommodate additional shapes of fastener head  112  that may not have been possible with other designs. Furthermore, applicator  200  can be made more compact because daubing lever  220  can be shortened as a result of this additional flexibility. 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 2A, 2B, and 6D , through opening  225  of daubing lever  220  has dogleg shape. The preceding subject matter of this paragraph characterizes example 9 of the present disclosure, wherein example 9 also includes the subject matter according to example 5, above. 
     A dogleg shape of through opening  225  is a specific example of a curved shape, which has an abrupt angle, which may be associated with catch  226 . The dogleg shape allows to delay the translational motion of daubing lever  220  relative to enclosure  210  until a certain angle of daubing lever  220  relative to enclosure  210  or, more specifically, of the dogleg profile of through opening  225  relative to the moment imparted by means  240  is reached. Once the threshold angle, defined by the dogleg shape, is reached, daubing lever  220  can start translating relative to enclosure  210 . 
     The dogleg shape and the translating delay associated with the dogleg shape may be used to accommodate fastener head  112  having particular shapes (e.g., a semi-spherical shape). 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIG. 5C , daubing lever  220  further comprises material passage  227 , located between actuation end  222   a  and working end  222   b  of daubing lever  220 . The preceding subject matter of this paragraph characterizes example 10 of the present disclosure, wherein example 10 also includes the subject matter according to any one of examples 5 to 9, above. 
     Material passage  227  allows material to flow through daubing lever  220  rather than around daubing lever  220 . This feature allows daubing lever  220  to more easily move within enclosure  210  when enclosure  210  is filled with material  104  and also to use wider stems for daubing lever  220 . 
     Material passage  227  may be a ring as, for example, shown in  FIG. 5C  or any other similar feature. Material passage  227  is designed such that actuation end  222   a  and working end  222   b  are supported with respect to each other and allow to transfer the moment through daubing lever  220 . The size and shape of material passage  227  may depend on viscosity of material, size of daubing lever  220 , size of enclosure  210 , and speed with which daubing lever  220  needs to travel through material  104 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIG. 5C , a line, perpendicular to a plane, containing the smallest circumferentially closed section of through opening  225 , lies in a first plane. A line, perpendicular to a plane, containing the smallest circumferentially closed section of material passage  227 , lies in a second plane. The first plane is perpendicular to the second plane. The preceding subject matter of this paragraph characterizes example 11 of the present disclosure, wherein example 11 also includes the subject matter according to example 10, above. 
     The orientation of material passage  227  may be substantially perpendicular to the direction of the motion of daubing lever  220  within enclosure  210 . This orientation ensures that material  104  more easily flow through material passage  227  than encountering various solid components of daubing lever  220 . 
     The first plane containing the smallest circumferentially closed section of through opening  225  is effectively the plane in which daubing lever  220  moves when it rotates and/or translates relative to enclosure  210 . As such, when daubing lever  220  moves through material  104 , the resisting forces will be within this plane or parallel to this plane. As such, material passage  227  or, more specifically, the second plane, containing the smallest circumferentially closed section of material passage  227 , may be perpendicular to the first plane to reduce the resistance. 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 2A and 2B , daubing lever  220  is translatable relative to enclosure  210 . The preceding subject matter of this paragraph characterizes example 12 of the present disclosure, wherein example 12 also includes the subject matter according to any one of examples 4, 5, and 7 to 11, above. 
     Daubing lever  220  may translate relative to enclosure  210  to accommodate various shapes of fastener head  112  and to ensure that working end  222   b  of daubing lever  220  remain in contact with fastener head  112  when enclosure is moved away from non-horizontal plane  116  of part  114 . 
     The translation may be provided by a slot in daubing lever  220  as described above. The translation direction may be defined by the shape of the slot. In some examples, daubing lever  220  may both translate and rotate relative to enclosure  210 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIG. 5D , daubing lever  220  further comprises tapered portion  229  between actuation end  222   a  and working end  222   b  of daubing lever  220 . The preceding subject matter of this paragraph characterizes example 13 of the present disclosure, wherein example 13 also includes the subject matter according to any one of examples 1 to 12, above. 
     Tapered portion  229  allows for material  104  to flow easily around daubing lever  220  when daubing lever  220  moves through material  104  (e.g., translates and/or rotates relative to enclosure  210 ). Specifically, tapered portion  229  reduces the drag experienced by daubing lever  220 . 
     Tapered portion  229  may include a fillet, chamfer, or any other suitable feature. Tapered portion  229  may be provided on one side of daubing lever  220  or both sides of daubing lever  220 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIG. 2D , a line, perpendicular to a plane, containing the smallest circumferentially closed section of through opening  225 , lies in a first plane. A symmetry plane of tapered portion  229  is perpendicular to the first plane. The preceding subject matter of this paragraph characterizes example 14 of the present disclosure, wherein example 14 also includes the subject matter according to example 13, above. 
     The orientation of tapered portion  229  may be substantially perpendicular to the direction of the motion of daubing lever  220  within enclosure  210 . This orientation ensures that material  104  more easily flow around daubing lever  220 . 
     The first plane containing the smallest circumferentially closed section of through opening  225  is effectively the plane in which daubing lever  220  moves when it rotates and/or translates relative to enclosure  210 . As such, when daubing lever  220  moves through material  104 , the resisting forces will be within this plane or parallel to this plane. As such, the orientation of tapered portion  229  or, more specifically, the symmetry plane of tapered portion  229  may be perpendicular to the first plane to reduce the resistance. 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIG. 2A , daubing lever  220  is movable relative to enclosure  210  such that abutment portion  228  of daubing lever  220  is capable of contacting interior surface  215  of enclosure  210 . The preceding subject matter of this paragraph characterizes example 15 of the present disclosure, wherein example 15 also includes the subject matter according to any one of examples 1 to 14, above. 
     Abutment portion  228  of daubing lever  220  acts as one of positive stops for the movement of daubing lever  220 . Once abutment portion  228  contacts interior surface  215  of enclosure  210 , daubing lever  220  cannot further move in this direction using the moment imparted by means  240 . 
     Daubing lever  220  is movable by the moment imparted by means  240  or forces applied to working end  222   b . When working end  222   b  initially contacts fastener head  112  (as, e.g., shown in  4 B), abutment portion  228  contacts interior surface  215  of enclosure  210 . As enclosure  210  moves closer to non-horizontal surface  116 , daubing lever  220  moves relative to enclosure  210  and abutment portion  228  loosed contact interior surface  215  (as, e.g., shown in  4 C). The contact is not established until working end  222   b  is being removed from fastener head  112  (as, e.g., shown in  4 G and  4 H). In other words, unless working end  222   b  contacts fastener head  112 , abutment portion  228  of daubing lever  220  acts as a positive stop for the movement of daubing lever  220 . 
     Abutment portion  228  may be a protrusion between actuation end  222   a  and working end  222   b  as, for example, schematically shown in  FIG. 2A . In other examples, abutment portion  228  may be positioned on actuation end  222   a  or working end  222   b . Furthermore, abutment portion  228  may be incorporated into means  240 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 5A and 5B , working end  222   b  of daubing lever  220  comprises one of roller  223   a  or curved paddle  223   b , The preceding subject matter of this paragraph characterizes example 16 of the present disclosure, wherein example 16 also includes the subject matter according to any one of examples 1 to 15, above. 
     Roller  223   a  or curved paddle  223   b  configuration of working end  222   b  allows working end  222   b  to translate relative to fastener head  112  (at least in a radial direction) without generating significant friction forces or catch on various protrusions on the surface of fastener head  112 . 
       FIG. 5A  illustrates working end  222   b  of daubing lever  220  comprising curved paddle  223   b . Curved paddle  223   b  can be easily cleaned after material  104  is removed from enclosure  210 .  FIG. 5B  illustrates working end  222   b  of daubing lever  220  comprising roller  223   a . Roller  223   a  can have a cylindrical shape. It should be noted that both roller  223   a  and curved paddle  223   b  are also capable of redistributing material  104  on fastener head  112 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIG. 2A , working end  222   b  of daubing lever  220  is operable to extend outside of interior space  211  of enclosure  210 . The preceding subject matter of this paragraph characterizes example 17 of the present disclosure, wherein example 17 also includes the subject matter according to any one of examples 1 to 16, above. 
     Working end  222   b  of daubing lever  220  may extend outside of interior space  211  to accommodate fastener head  112  that may have a small thickness, but a large diameter. 
     For example, when daubing lever  220  is rotatable relative to enclosure  210 , any radial travel of working end  222   b  would have a corresponding axial travel. As such, when a large radial travel is needed, working end  222   b  may extend outside of interior space  211  of enclosure  210  such that a sufficient radial travel occurs before enclosure  210  seals against non-horizontal surface  116 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIG. 3 , method  300  of applying material  104  onto fastener head  112 , protruding from non-horizontal surface  116  of part  114 , is disclosed. The material  104  is applied using applicator  200 , comprising enclosure  210 , daubing lever  220 , extending within interior space  211  of enclosure  210 , and means  240  for imparting moment on daubing lever  220  to bias abutment portion  228  of daubing lever  220  toward enclosure  210 . Method  300  comprises advancing applicator  200  toward non-horizontal surface  116  of part  114  along an axis that is perpendicular to non-horizontal surface  116  to establish contact between working end  222   b  of daubing lever  220  and fastener head  112  and to cause abutment portion  228  of daubing lever  220  to move away from enclosure  210  (block  320  in  FIG. 3 ). Method  300  also comprises pressing sealing rim  212  of enclosure  210  against non-horizontal surface  116  of part  114  around fastener head  112  (block  330  in  FIG. 3 ). Method  300  additionally comprises at least partially filling enclosure  210  with material  104  (block  340  in  FIG. 3 ). Method  300  further comprises retracting applicator  200  away from non-horizontal surface  116  along axis perpendicular to non-horizontal surface  116  (block  350  in  FIG. 3 ) while maintaining contact between working end  222   b  of daubing lever  220  and fastener head  112  (block  352  in  FIG. 3 ) to enable means  240  for imparting moment on daubing lever  220  to cause working end  222   b  of daubing lever  220  to move relative to enclosure  210  (block  353  in  FIG. 3 ) across fastener head  112  and to asymmetrically distribute material  104 , at least partially filling enclosure  210 , across fastener head  112  (block  354  in  FIG. 3 ) such that more of material  104  is located along top half of fastener head  112  then along bottom half of fastener head  112 . The preceding subject matter of this paragraph characterizes example 18 of the present disclosure. 
     Method  300  yields asymmetrical distribution of material  104  on fastener head  112 , which may be used, for example, to compensate for gravitation sagging of material  104  when material  104  cures. This asymmetrical distribution is achieved when working end  222   b  moves across fastener head  112  at least in the radial direction. Specifically, retracting applicator  200  away from non-horizontal surface  116  along axis  202  perpendicular to non-horizontal surface causes working end  222   b  of daubing lever  220  to move relative to enclosure  210  across fastener head  112  and to asymmetrically distribute material  104 . 
     When working end  222   b  of daubing lever  220  initially contacts fastener head  112 , working end  222   b  slides in a first radial direction across fastener head  112  and also causes abutment portion  228  of daubing lever  220  to move away from enclosure  210 . This sliding occurs while applicator  200  is being advanced toward non-horizontal surface  116  of part  114  and until sealing rim  212  of enclosure  210  is pressed against non-horizontal surface  116  of part  114  around fastener head  112 . Once enclosure  210  at least partially-filled with material  104  such that material  104  contacts fastener head  112  and, in some examples, a portion of non-horizontal surface  116  within enclosure  210 , applicator  200  is retracted away from non-horizontal surface  116  along axis  202 . The contact between working end  222   b  of daubing lever  220  and fastener head  112  is maintained. Furthermore, working end  222   b  of daubing lever  220  moves relative to enclosure  210  across fastener head  112  and asymmetrically distributes material  104  across fastener head  112 . At the end of this distribution, more of material  104  is located along top half of fastener head  112  then along bottom half of fastener head  112 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 3, 2A, and 2B , according to method  300 , as applicator  200  is retracted away from non-horizontal surface  116  along axis  202  perpendicular to non-horizontal surface  116  while maintaining contact between working end  222   b  of daubing lever  220  and fastener head  112 , daubing lever  220  rotates relative to enclosure  210  (block  356  in  FIG. 3 ). The preceding subject matter of this paragraph characterizes example 19 of the present disclosure, wherein example 19 also includes the subject matter according to example 18, above. 
     Rotation of daubing lever  220  relative to enclosure  210  allows to retract enclosure  210  away from non-horizontal surface  116  while maintaining contact between working end  22   b  of daubing lever  220  and fastener head  112 . The rotation effectively allows working end  222   b  to move along axis  202  relative to enclosure  210 . It should be noted that this rotation also move working end  222   b  radially relative to enclosure  210  (e.g., perpendicular to axis  202 ). 
     Rotation of daubing lever  220  relative to enclosure  210  may be achieved using a combination of shank  230  of enclosure  210  and through opening  225  of daubing lever  220 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 3, 2A, 2B, and 6B-6D , according to method  300 , as applicator  200  is retracted away from non-horizontal surface  116  along axis perpendicular to non-horizontal surface  116  while maintaining contact between working end  222   b  of daubing lever  220  and fastener head  112 , daubing lever  220  translates relative to enclosure  210  (block  357  in  FIG. 3 ). The preceding subject matter of this paragraph characterizes example 20 of the present disclosure, wherein example 20 also includes the subject matter according to example 19, above. 
     Translation of daubing lever  220  relative to enclosure  210  allows to retract enclosure  210  away from non-horizontal surface  116  while maintaining contact between working end  222   b  of daubing lever  220  and fastener head  112 . In other words, this translation effectively allows working end  222   b  to move along axis  202  relative to enclosure  210 . 
     Rotation of daubing lever  220  relative to enclosure  210  may be achieved using a combination of shank  230  of enclosure  210  and through opening  225  of daubing lever  220 , which may be a slot. The slot may a straight slot as shown, for example in  FIG. 6B . Alternatively, the slot may a curved slot as, for example, shown in  FIGS. 6C and 6D . More specifically, a curved slot may include catch as, for example, shown in  FIG. 6D . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 3 and 4E , according to method  300 , enclosure  210  is at least partially filled with material  104  by injecting material  104  into enclosure  210  through inlet  217  (block  342  in  FIG. 3 ). The preceding subject matter of this paragraph characterizes example 21 of the present disclosure, wherein example 21 also includes the subject matter according to any one of examples 18 to 20, above. 
     Enclosure  210  is filled with material  104  in order to transfer material  104  onto fastener head  112  and onto non-horizontal surface  116  around fastener head  112 . Specifically, when enclosure  210  is in contact with non-horizontal surface  116 , material  104  contacts fastener head  112  and non-horizontal surface  116  and remains on fastener head  112  and non-horizontal surface  116  when enclosure  210  is later retracted. Inlet  217  is used to deliver material  104  into enclosure  210 . 
     Inlet  217  may be used to couple enclosure  210  with a material dispenser device, such as a caulking gun, applicator, and the like. Inlet  217  may include dispenser adapter  250  as, for example, shown in  FIG. 2A . When material  104  is provide into enclosure  210 , material  104  may completely fill enclosure  210  to prevent voids and incomplete sealing of fastener head  112 , non-horizontal surface  116 , and/or an interface between fastener head  112  and non-horizontal surface  116 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 3 and 4E-4G , according to method  300 , causing working end  222   b  of daubing lever  220  to move relative to enclosure  210  while retracting applicator  200  away from non-horizontal surface  116  along axis perpendicular to non-horizontal surface  116  comprises flowing material  104  relative to daubing lever  220 , extending within interior space  211  of enclosure  210  (block  343  in  FIG. 3 ). The preceding subject matter of this paragraph characterizes example 22 of the present disclosure, wherein example 22 also includes the subject matter according to any one of examples 18 to 21, above. 
     When daubing lever  220  moves relative to enclosure  210  (and within enclosure  210 ) and when interior space  211  of enclosure  210  is filled with material  102 , daubing lever  220  moves through material  104  within interior space  211  and material  104  flows relative to daubing lever  220 . In other words, material  104  flows relative to daubing lever  220 . 
     Daubing lever  220  may include various features, such as tapered portion  229  and material passage  227 , to allow material  104  to flow more easily relative to daubing lever  220  and to ensure that the flow of material  104  does not causes uneven distribution of material  140  within enclosure  210 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 3 and 4E-4G , according to method  300 , flowing material  104  relative to daubing lever  220 , extending within interior space  211  of enclosure  210 , comprises flowing at least portion of material  104  around daubing lever  220  (block  344  in  FIG. 3 ). The preceding subject matter of this paragraph characterizes example 23 of the present disclosure, wherein example 23 also includes the subject matter according to example 22, above. 
     Material  104  flows around daubing lever  220  while daubing lever  220  moves within interior space  211  of enclosure  210  filled with material  104 . 
     Daubing lever  220  may include various features, such as tapered portion  229  to allow material  104  to flow more easily around daubing lever  220  and to ensure that the flow of material  104  does not causes uneven distribution of material  140  within enclosure  210 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 3 and 4E-4G , according to method  300 , flowing at least portion of material  104  around daubing lever  220 , extending within interior space  211  of enclosure  210 , comprises flowing at least portion of material  104  around tapered portion  229  of daubing lever  220 . The preceding subject matter of this paragraph characterizes example 24 of the present disclosure, wherein example 24 also includes the subject matter according to example 23, above. 
     Daubing lever  220  may have tapered portion  229 , which allows material  104  to more easily flow around daubing lever  220  when daubing lever  220  moves within enclosure  210  filled with material  104 . Tapered portion  229  effectively reduces the drag of material  104  onto daubing lever  220 . 
     Tapered portion  229  may include a fillet, chamfer, or any other suitable feature. Tapered portion  229  may be provided on one side of daubing lever  220  or both sides of daubing lever  220 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 3 and 4E-4G , according to method  300 , flowing material  104  relative to daubing lever  220 , extending within interior space  211  of enclosure  210 , comprises flowing at least portion of material  104  through daubing lever  220  (block  344  in  FIG. 3 ). The preceding subject matter of this paragraph characterizes example 25 of the present disclosure, wherein example 25 also includes the subject matter according to any one of examples 22 to 24, above. 
     When daubing lever  220  moves within enclosure  210  filled with material  104 , daubing lever  220  also moves relative to material  104 . Material  104  may flow through daubing lever  220  if, for example, daubing lever  220  comprises material passage  227 . Reducing the resistance to this flow (e.g., by allowing material  104  to flow through daubing lever  220 ) ensures that working end  222   b  remains in contact with fastener head  112  and allows to increase the speed with which enclosure  210  is being retracted from non-horizontal surface  116 . 
     Material passage  227  may be a ring as, for example, shown in  FIG. 5C  or any other similar feature. Material passage  227  is designed such that actuation end  222   a  and working end  222   b  are supported with respect to each other and allow to transfer the moment through daubing lever  220 . The size and shape of material passage  227  may depend on viscosity of material, size of daubing lever  220 , size of enclosure  210 , and speed with which daubing lever  220  needs to travel through material  104 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIG. 5C , according to method  300 , flowing at least portion of material  104  through daubing lever  220  comprises flowing at least portion of material through material passage  227  in daubing lever  220 . The preceding subject matter of this paragraph characterizes example 26 of the present disclosure, wherein example 26 also includes the subject matter according to example 25, above. 
     Daubing lever  220  may have material passage  227  as, for example, shown in  FIG. 5C  which allows material  104  to flow through daubing lever  220 . 
     Material passage  227  may be a ring as, for example, shown in  FIG. 5C  or any other similar feature. Material passage  227  is designed such that actuation end  222   a  and working end  222   b  are supported with respect to each other and allow to transfer the moment through daubing lever  220 . The size and shape of material passage  227  may depend on viscosity of material, size of daubing lever  220 , size of enclosure  210 , and speed with which daubing lever  220  needs to travel through material  104 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 3 and 4E-4G , according to method  300 , moving working end  222   b  of daubing lever  220  relative to enclosure  210  across fastener head  112  comprises sliding working end  222   b  of daubing lever  220  across fastener head  112 . The preceding subject matter of this paragraph characterizes example 27 of the present disclosure, wherein example 27 also includes the subject matter according to any one of examples 18 to 26, above. 
     Sliding working end  222   b  of daubing lever  220  across fastener head  112  ensures that working end  222   b  remains in contact with fastener head  112 . Specifically, when enclosure  210  is retracted, working end  222   b  redistributes material  104  on fastener head  112 . 
     Sliding working end  222   b  of daubing lever  220  across fastener head  112  is enabled by means  240 , which impart the moment on daubing lever  220  to cause working end  222   b  of daubing lever  220  to move relative to enclosure  210  and across fastener head  112 . This in turn causes asymmetrical distribution of material  104  such that more material  104  is located along the top half of fastener head  112  then along the bottom half of fastener head  112 . 
     Referring generally to  FIGS. 4E-4G  and particularly to, e.g.,  FIG. 5B , according to method  300 , moving working end  222   b  of daubing lever  220  relative to enclosure  210  across fastener head  112  comprises rolling working end  222   b  of daubing lever  220  across fastener head  112 . The preceding subject matter of this paragraph characterizes example 28 of the present disclosure, wherein example 28 also includes the subject matter according to any one of examples 18 to 26, above. 
     Working end  222   b  of daubing lever  220  may have roller  223   a  as, for example, shown in  FIG. 5B , which allows working end  222   b  to roll across fastener head  112 , thereby reducing the drag of working end  222   b  relative to fastener head  112 , catching various surface features on fastener head  112  with working end  222   b , and reduce potential damage (e.g., scratching to working end  222   b  and fastener head  112 ). 
       FIG. 5B  illustrates working end  222   b  of daubing lever  220  comprising roller  223   a . Roller  223   a  can have a cylindrical shape. It should be noted that both roller  223   a  and curved paddle  223   b  are also capable of redistributing material  104  on fastener head  112 . 
     Referring generally to  FIG. 3  and particularly to, e.g.,  FIGS. 4F-4H , method  300  further comprises continuing to retract applicator  200  away from non-horizontal surface  116  along axis perpendicular to non-horizontal surface  116  until contact between working end  222   b  of daubing lever  220  and fastener head  112  is terminated and abutment portion  228  of daubing lever  220  contacts enclosure  210 . The preceding subject matter of this paragraph characterizes example 29 of the present disclosure, wherein example 29 also includes the subject matter according to any one of examples 18 to 28, above. 
     Once working end  222   b  completes redistribution of material  104  on fastener head  112  as, for example, schematically shown in  FIG. 4G , working end  222   b  may be retracted from fastener head  112 . At this point, abutment portion  228  of daubing lever  220  contacts enclosure  210  such daubing lever  220  cannot further move relative to enclosure under the force from means  240 . 
     Referring generally to  FIG. 1  and particularly to, e.g.,  FIGS. 4I-4J , method  300  further comprises using gravity to symmetrically redistribute across fastener head  112  material  104  that was asymmetrically distributed across fastener head  112  by working end  222   b  of daubing lever  220 . The preceding subject matter of this paragraph characterizes example 30 of the present disclosure, wherein example 30 also includes the subject matter according to example 29, above. 
     After working end  222   b  completes redistribution of material  104  on fastener head  112  and working end  222   b  is retracted away from fastener head  112 , material  104  is not supported by working end  222   b  and the gravitation force may redistribute material  104  across fastener head  112 . This gravitation redistribution of material  104  may even out material  104  on fastener head  112 . 
     Examples of the present disclosure may be described in the context of aircraft manufacturing and service method  1100  as shown in  FIG. 7  and aircraft  1102  as shown in  FIG. 8 . During pre-production, illustrative method  1100  may include specification and design (block  1104 ) of aircraft  1102  and material procurement (block  1106 ). During production, component and subassembly manufacturing (block  1108 ) and system integration (block  1110 ) of aircraft  1102  may take place. Thereafter, aircraft  1102  may go through certification and delivery (block  1112 ) to be placed in service (block  1114 ). While in service, aircraft  1102  may be scheduled for routine maintenance and service (block  1116 ). Routine maintenance and service may include modification, reconfiguration, refurbishment, etc. of one or more systems of aircraft  1102 . 
     Each of the processes of illustrative method  1100  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 vendors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on. 
     As shown in  FIG. 8 , aircraft  1102  produced by illustrative method  1100  may include airframe  1118  with a plurality of high-level systems  1120  and interior  1122 . Examples of high-level systems  1120  include one or more of propulsion system  1124 , electrical system  1126 , hydraulic system  1128 , and environmental system  1130 . Any number of other systems may be included. Although an aerospace example is shown, the principles disclosed herein may be applied to other industries, such as the automotive industry. Accordingly, in addition to aircraft  1102 , the principles disclosed herein may apply to other vehicles, e.g., land vehicles, marine vehicles, space vehicles, etc. 
     Apparatus(es) and method(s) shown or described herein may be employed during any one or more of the stages of the manufacturing and service method  1100 . For example, components or subassemblies corresponding to component and subassembly manufacturing (block  1108 ) may be fabricated or manufactured in a manner similar to components or subassemblies produced while aircraft  1102  is in service (block  1114 ). Also, one or more examples of the apparatus(es), method(s), or combination thereof may be utilized during production stages  1108  and  1110 , for example, by substantially expediting assembly of or reducing the cost of aircraft  1102 . Similarly, one or more examples of the apparatus or method realizations, or a combination thereof, may be utilized, for example and without limitation, while aircraft  1102  is in service (block  1114 ) and/or during maintenance and service (block  1116 ). 
     Different examples of the apparatus(es) and method(s) disclosed herein include a variety of components, features, and functionalities. It should be understood that the various examples of the apparatus(es) and method(s) disclosed herein may include any of the components, features, and functionalities of any of the other examples of the apparatus(es) and method(s) disclosed herein in any combination, and all of such possibilities are intended to be within the scope of the present disclosure. 
     Many modifications of examples set forth herein will come to mind to one skilled in the art to which the present disclosure pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. 
     Therefore, it is to be understood that the present disclosure is not to be limited to the specific examples illustrated and that modifications and other examples are intended to be included within the scope of the appended claims. Moreover, although the foregoing description and the associated drawings describe examples of the present disclosure in the context of certain illustrative combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative implementations without departing from the scope of the appended claims. Accordingly, parenthetical reference numerals in the appended claims are presented for illustrative purposes only and are not intended to limit the scope of the claimed subject matter to the specific examples provided in the present disclosure.