Abstract:
A closure apparatus for a bottle neck and cap increases the torque necessary to remove the cap from the bottle neck. Projections are provided on one of the bottle neck exterior and cap interior, and indentations are provided on the other of the bottle neck exterior and cap interior. When the cap is secured on the bottle neck, the projections engage in the indentations. The engagement of the projections in the indentations requires an increased torque to remove the cap from the bottle neck.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     (1) Field of the Invention  
         [0002]     The present invention pertains to a closure apparatus for a bottle neck and cap that increases the torque necessary to remove the cap from the bottle neck. More specifically, projections are provided on one of the bottle neck and cap interior, and indentations are provided on the other of the bottle neck and cap interior. When the cap is secured on the bottle neck, the projections engage in the indentations. The engagement of the projections in the indentations requires an increased torque to remove the cap from the bottle neck.  
         [0003]     (2) Description of the Related Art  
         [0004]     A typical bottle and cap closure apparatus comprises a bottle neck having one or more exterior screw threads that engage with interior screw threads of the cap. The cap is positioned on top of the bottle neck and turned in the clockwise direction relative to the bottle to screw the interior threads of the bottle cap onto the exterior threads of the bottle neck. To remove the cap from the bottle neck, the cap is rotated in the opposite, counterclockwise direction. In both attaching the cap to the bottle neck and removing the cap from the bottle neck, it is the sliding engagement between the exterior screw threads of the bottle neck and the interior screw threads of the cap that attach the cap to the bottle neck and remove the cap from the bottle neck.  
         [0005]     When the cap is secured tightly on the bottle neck, it is the friction engagement between the bottle neck exterior screw threads and the cap interior screw threads that securely holds the cap to the bottle neck. This friction engagement between the screw threads of the bottle neck and the cap also often affects the quality of the liquid seal between the cap and bottle. Typically, when the cap is screwed tightly down on the bottle neck, an annular surface at the top of the bottle neck will engage in sealing engagement with an interior surface of the cap, thereby providing a liquid seal between the cap and bottle neck. If the cap is loose on the bottle neck due to the cap not being screwed down entirely on the bottle neck liquid contained in the bottle could potentially leak through the connection.  
         [0006]     A disadvantage often encountered in the constructions of bottle and cap closures of the type described above is the tendency of the cap to become loose from the bottle neck. When the cap is screwed down tightly onto the bottle neck providing a seal between the bottle neck and the cap, often only the friction engagement between the external screw threads of the bottle neck and the internal screw threads of the cap holds the cap in its sealed position against the top of the bottle neck. When the cap and bottle neck are subjected to certain conditions, for example when the cap and bottle neck are vibrated when being transported, the cap can have a tendency to move in a counterclockwise rotation on the bottle neck due to the spiraling configurations of the exterior screw threads of the bottle neck and the interior screw threads of the cap. This counterclockwise rotation of the cap is called “backing off”, and can cause leakage of a liquid contained in the bottle.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention provides a bottle and cap closure apparatus that overcomes disadvantages associated with the constructions of prior art bottle and cap closure apparatus by providing an enhanced torque feature. The enhanced torque feature of the bottle and cap closure apparatus of the invention securely holds the cap on the bottle neck and requires an increased counterclockwise torque on the bottle cap to remove the cap from the bottle neck, thereby preventing the backing off of the cap from the bottle neck. The bottle and cap closure apparatus of the invention is provided in several different embodiments, with each embodiment employing a basic concept of the invention.  
         [0008]     A first embodiment of the bottle and cap closure apparatus of the invention improves the conventional construction of a bottle and cap closure. The apparatus is employed on a bottle neck having an exterior screw thread that spirals around the bottle neck, and a bottle cap having an interior screw thread that spirals around the interior of the cap. The bottle neck screw thread and the cap screw thread are mated and screwed together in attaching the cap to the bottle neck in the conventional manner. However, the bottle and cap closure apparatus of the invention differs from the constructions of prior art bottle and cap closure apparatus by providing a number of projections that extend axially outwardly from a flank surface of the bottle neck screw thread. The same number of indentations extend axially into a flank surface of the cap screw thread.  
         [0009]     In attaching the cap to the bottle neck, the axial projections on the bottle neck screw thread extend into the axial indentations in the cap screw thread and thereby securely hold the cap on the bottle neck and prevent backing off of the cap. To remove the cap from the bottle neck a sufficient torque force must be exerted on the cap to cause the disengagement of the bottle neck screw thread projections from the cap screw thread indentations.  
         [0010]     A second embodiment of the bottle and cap closure apparatus is similar in construction to the first embodiment, except that the axial indentations are provided in the bottle neck screw thread, and the axial projections are provided on the bottle cap screw thread. The bottle cap projections are received in the bottle neck indentations to securely hold the cap to the bottle neck and to prevent backing off of the cap. Like the previously described embodiment, to remove the cap from the bottle neck a sufficient torque force must be exerted on the bottle cap to cause the disengagement of the bottle cap screw thread projections from the bottle neck screw thread indentations.  
         [0011]     A third embodiment of the bottle and cap closure apparatus is similar to the previously described embodiments, except that it comprises a number of projections that project radially outwardly from the bottle neck adjacent the bottle neck screw threads. The screw thread of the cap is provided with an equal number of indentations that extend radially into the screw thread of the cap. In attaching the cap to the bottle neck, the radial projections on the bottle neck extend into the radial indentations on the cap to securely hold the cap to the bottle neck and to prevent backing off of the cap. In order to remove the cap from the bottle neck, a sufficient torque force must be exerted to cause the bottle neck projections to disengage from the bottle cap indentations.  
         [0012]     In each of the embodiments of the bottle and cap closure apparatus described above, the engagement of projections on one of the bottle neck and cap into indentations of the other of the bottle neck and cap securely holds the cap to the bottle neck and prevents the unintended backing off of the bottle cap.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     Further features of the invention are set forth in the following detailed descriptions of the preferred embodiments of invention, and in the drawing figures wherein:  
         [0014]      FIG. 1  is a partial view of a bottle employing a first embodiment of the bottle and cap closure apparatus of the invention;  
         [0015]      FIG. 2  is a cross-section of a bottle cap employing the bottle and cap closure apparatus of  FIG. 1 ;  
         [0016]      FIG. 3  is a partial view of a bottle employing a second embodiment of the bottle and cap closure apparatus of the invention;  
         [0017]      FIG. 4  is a cross-section of a bottle cap employing the bottle and cap closure apparatus of  FIG. 3 ;  
         [0018]      FIG. 5  is a partial view of a bottle employing a third embodiment of the bottle and cap closure apparatus of the invention; and,  
         [0019]      FIG. 6  is a cross-section of a bottle cap employing the bottle and cap closure apparatus of  FIG. 5 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]     Each of the embodiments of the bottle neck closure apparatus to be described could simply be used to close the opening of a bottle, or could be used as an attachment for another component to the bottle, for example a hand operated trigger sprayer. In each of the embodiments to be described the component parts of the embodiments are constructed of materials typically used in the construction of bottle and cap closures, for example plastic material. A first embodiment of the bottle and cap closure apparatus of the invention is shown in  FIGS. 1 and 2 .  
         [0021]      FIG. 1  shows an upper portion of a bottle  12  having a cylindrical bottle neck  14 . The bottle neck  14  surrounds an opening to an interior volume of the bottle. The bottle neck and bottle opening have a center axis  16  that defines mutually perpendicular axial and radial directions relative to the bottle  12  and the bottle neck  14 . The bottle neck  14  has a cylindrical exterior surface  18  that extends upwardly from the bottle  12  to an annular end surface  22  of the neck that surrounds the bottle opening. The features of the bottle described above are typical in the construction of most bottles.  
         [0022]     The novel features of the invention are provided in the construction of a bottle screw thread  24  on the bottle neck exterior surface  18 . The bottle screw thread  24  has a length that extends from a first end  26  of the thread to a second end  28  of the thread. The thread first end  26  is positioned adjacent the annular end surface  22  of the bottle neck. From the first end  26 , the screw thread spirals around the bottle neck exterior surface  18  to the thread second end  28  positioned adjacent the bottle  12 . The screw thread  24  is formed with opposite flank surfaces  32 ,  34  that extend the length of the thread. The thread is also formed with a crest surface  36  that separates the opposite flank surfaces  32 ,  34  of the thread. The crest surface  36  also extends the length of the thread.  
         [0023]     The construction of the bottle screw thread  24  differs from that of conventional screw threads in that it is provided with a plurality of projections  38  that project axially from one of the thread flank surfaces  34 . In the embodiment of the bottle shown in  FIG. 1 , the projections  38  project axially downwardly from the lower flank surface  34  positioned on the underside of the screw thread  24 . Although four projections  38  are shown in  FIG. 1 , a greater number of projections or a lesser number of projections could also be employed. The projections  38  have a general triangular configuration and are separated from each other by portions of the screw thread flank surface  34 . Constructing the bottle  12  of a plastic material gives the projections  38  a resilience that allows the projections  38  to compress and deflect slightly when attaching the cap  42  to the bottle neck  14 . In the preferred embodiment of the invention, the projections  38  are positioned adjacent the second end  28  of the screw thread. Although only one screw thread  24  is shown on the bottle neck in  FIG. 1 , the one screw thread could be replaced by a pair of screw threads of shorter length.  
         [0024]      FIG. 2  shows the construction of a cap  42  that is employed with the bottle  12  of  FIG. 1 . The cap  42  shown is adapted for use in attaching a trigger sprayer to the bottle  12 , and therefore has an opening through the top of the cap. The cap is shown in cross section to provide a better view of the novel construction of the interior of the cap. In variant embodiments of the cap  42 , the top of the cap could be closed to provide a sealing closure for the bottle  12 .  
         [0025]     The cap  42  has a cylindrical side wall  44  with a cylindrical interior surface  46 . The interior surface  46  extends axially downwardly from the top of the cap  42  to a bottom annular end surface  48  of the cap. The cap end surface  48  and interior surface  46  surround an interior volume of the cap that is dimensioned to receive the bottle neck  14  in securing the cap  42  on the bottle  12 . The construction of the cap described to this point is typical among many caps.  
         [0026]     The novel construction of the cap  42  is provided in the particular construction of an internal screw thread  52  that spirals around the cap interior surface  46 . The cap screw thread  52  has a length with a first end  54  adjacent the top of the cap sidewall  44 , and an opposite second end  56  adjacent the annular end surface  48  of the cap. The screw thread is formed with opposite flank surfaces  62 ,  64  that extend the length of the screw thread between the first  54  and second  56  ends. A crest surface  66  of the thread separates the two flank surfaces  62 ,  64  and also extends the length of the thread from the first end  54  to the second end  56 .  
         [0027]     A plurality of indentations  68  extend into the cap screw thread  52 . The number of indentations  68  corresponds to the number of projections  38  on the bottle screw thread  24 . The indentations  68  extend axially downwardly into the top flank surface  62  of the screw thread as shown in  FIG. 2 . The spatial arrangement of the indentations  68  in the flank surface  62  corresponds to the spatial arrangement of the projections  38  on the bottle screw thread  24 . The indentations  68  are also provided adjacent the second end  56  of the cap screw thread  52 .  
         [0028]     In attaching the cap  42  to the bottle  12 , the cap  42  is screw threaded on the bottle neck  14  in the conventional manner. However, as the cap  42  is screwed down on the bottle neck  14 , the cap screw thread indentations  68  approach the bottle screw thread projections  38 . As the cap  42  is tightened down on the bottle neck  14 , the bottle neck screw thread projections  38  will align with and extend into the cap screw thread indentations  68 . This securely holds the cap  42  on the bottle neck  14  and prevents backing off of the cap from the bottle neck. To remove the cap  42  from the bottle neck  14  a sufficient torque must be exerted on the cap to cause the disengagement of the bottle neck screw thread projections  38  from the cap screw thread indentations  68 .  
         [0029]     A second embodiment of the bottle and cap closure apparatus of the invention is shown in  FIGS. 3 and 4 . This second embodiment is similar in construction to that of the previously described embodiment shown in  FIGS. 1 and 2 , and common structural features of the second embodiment to those of the first embodiment are labeled with the same reference numbers followed by a prime (′). Because the second embodiment has common structural features to the first embodiment that have already been described with reference to  FIGS. 1 and 2 , these common structural features will not again be described.  
         [0030]     Referring to  FIG. 3  of the drawings, the bottle neck screw thread  24 ′ of the second embodiment of the apparatus differs in construction from that of the first embodiment in that the projections  38  of the first embodiment are replaced by a plurality of triangular indentations  72 . As shown in  FIG. 3 , the plurality of indentations  72  have a general triangular configuration and extend axially upwardly into the bottom flank surface  34 ′ of the bottle screw thread  24 ′. In a similar manner to the previously described embodiment, the bottle thread indentations  72  are positioned adjacent the second end  28 ′ of the bottle screw thread  24 ′.  
         [0031]     The cap  42 ′ of the second embodiment of the invention shown in  FIG. 4  differs in construction from that of the first embodiment in that the screw thread indentations  68  of the first embodiment of the cap are replaced by screw thread projections  74  on the second embodiment of the cap. As shown in  FIG. 4 , the shape and number of cap screw thread projections  74  correspond to the shape and number of bottle screw thread indentations  72 . The spatial positioning of the cap projections  74  also corresponds to that of the bottle thread indentations  72 .  
         [0032]     In attaching the cap  42 ′ to the bottle neck  14 ′, the cap is first initially screw threaded onto the bottle neck. As the cap  42 ′ is tightened down on the bottle neck  14 ′, the cap projections  74  approach the bottle thread indentations  72 . The projections  74  engage in the indentations  72  as the cap is tightened down on the bottle neck, thereby securely holding the cap  42 ′ on the bottle neck  14 ′ and preventing the backing off of the cap. To remove the cap  42 ′ from the bottle neck  14 ′ a sufficient torque must be exerted on the cap to cause the disengagement of the cap projections  74  from the bottle indentations  72 .  
         [0033]     A third embodiment of the bottle and cap closure apparatus is shown in  FIGS. 5 and 6 . This third embodiment is similar in construction to that of the first described embodiment of the invention shown in  FIGS. 1 and 2 , and common structural features of the third embodiment to those of the first embodiment are labeled with the same reference numbers followed by a double prime (″). Because the third embodiment has common structural features to the first embodiment that have already been described with reference to  FIGS. 1 and 2 , these common structural features will not again be described.  
         [0034]     Referring to  FIG. 5  of the drawings, the bottle neck screw thread  24 ″ of the third embodiment of the apparatus differs in construction from that of the first embodiment in that the projections  38  of the first embodiment are replaced by a plurality of projections  82  that extend axially downwardly from the lower flank surface  34 ″ across the exterior surface  18 ″ of the bottle neck  14 ″. As seen in  FIG. 5 , each of the projections  82  extends downwardly from the thread flank surface  34 ″ to the bottle  12 ″ where the bottle neck  14 ″ extends outwardly from the bottle. Thus, the projections  82  are formed as three adjacent columns that have general trapezoidal cross sections that project radially outwardly from the bottle neck  14 ″. In a similar manner to the previously described embodiments, the bottle thread projections  82  are positioned adjacent the second end  28 ″ of the bottle screw thread  24 ″.  
         [0035]     The cap  42 ″ of the second embodiment of the invention shown in  FIG. 6  differs in construction from that of the first embodiment in that the screw thread indentations  68  of the first embodiment of the cap are replaced by screw thread indentations  84  on the third embodiment of the cap. As shown in  FIG. 6 , the cap screw thread indentations  84  correspond in shape and in number to the bottle screw thread projections  82 . The spatial positioning of the cap indentations  84  also corresponds to that of the bottle thread projections  82 . However, the cap thread indentations  84  extend radially into the crest surface  66 ″ of the cap screw thread. Thus, the cap indentations  84  form grooves that extend completely across the cap screw thread  52 ″ between the screw thread flank surfaces  62 ″,  64 ″.  
         [0036]     In attaching the cap  42 ″ to the bottle neck  14 ″, the cap is first initially screw threaded on the bottle neck. As the cap  42 ″ is tightened down on the bottle neck  14 ″, the cap indentations  84  approach the bottle neck projections  82 . The bottle neck projections  82  engage in the cap indentations  84  as the cap is tightened down on the bottle neck, thereby securely holding the cap  42 ″ on the bottle neck  14 ″ and preventing the backing off of the cap. To remove the cap  42 ″ from the bottle neck  14 ″ a sufficient torque must be exerted on the cap to cause the disengagement of the bottle neck projections  82  from the cap indentations  84 .  
         [0037]     While the present invention has been described above by reference to specific embodiments of the invention, it should be understood that modifications and variations could be made to the bottle and cap closure apparatus without departing from the intended scope of the following claims.