Abstract:
A modified spray cap and extension tube. Positive mechanical interlocking features are added which lock the extension tube to the cap. The extension tube therefore does not fly out of the cap when in use. The modified spray cap is configured so that a conventional diffused spray pattern is still achieved when the modified extension tube is removed.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to the field of aerosol spray cans. More specifically, the invention comprises a revised extension tube that locks to the spray cap when in use.  
         [0003]     2. Description of the Related Art  
         [0004]     Aerosol spray cans tend to deliver a diffused spray. In some applications, such as the precise deposition of lubricants, this diffused pattern is undesirable. Where precise application is needed, an extension tube has customarily been used.  
         [0005]      FIG. 1  shows a prior art aerosol can  10 . To dispense its contents, the user pressed down on spray cap  12 . A diffused spray pattern then issues from orifice  16 . Extension tube  18 , which is simply a long hollow piece of plastic, can be inserted into orifice  16 . In some prior art devices, orifice  16  is contained within nozzle insert  14 . Gripping features, such as small ribs or pliable materials, can be included within nozzle insert  14 . These help frictionally retain the portion of extension tube  18  that is thrust into orifice  16 . However, those skilled in the art will know that this frictional retention approach is only marginally effective. The contents of aerosol can  10  issue forth under considerable pressure. They may also have significant lubricating value. These two factors degrade the prior art devices&#39; ability to retain extension tube  18  in position. In fact, it is not uncommon for an extension tube  18  to be launched out of spray cap  12  like a projectile.  
       BRIEF SUMMARY OF THE INVENTION  
       [0006]     The present invention comprises a modified spray cap and extension tube. Positive mechanical interlocking features are added which lock the extension tube to the cap. The extension tube therefore does not fly out of the cap when in use. The modified spray cap is configured so that a conventional diffused spray pattern is still achieved when the modified extension tube is removed. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0007]      FIG. 1  is an isometric view, showing a prior art spray cap and extension tube.  
         [0008]      FIG. 2  is an isometric view, showing a modified spray cap and extension tube.  
         [0009]      FIG. 3  is an isometric sectional view, showing the internal features of the modified spray cap.  
         [0010]      FIG. 4  is a hidden line view, showing the modified extension tube.  
         [0011]      FIG. 5  is an isometric view, showing an alternate embodiment of the modified extension tube.  
         [0012]      FIG. 5B  is an isometric view, showing an alternate embodiment of the modified spray cap.  
         [0013]      FIG. 6  is an isometric view, showing the modified extension tube locked into the modified spray cap.  
         [0014]      FIG. 7  is an isometric sectional view, showing an alternate embodiment of the present invention.  
         [0015]      FIG. 8  is an isometric sectional view, showing an alternate embodiment of the present invention.  
         [0016]      FIG. 9  is a hidden line view, showing an alternative embodiment of the modified spray cap.  
         [0017]      FIG. 9B  is a hidden line view, showing an alternative embodiment of the modified spray cap.  
         [0018]      FIG. 10  is a hidden line view, showing an alternative embodiment of the modified spray tube.  
         [0019]      FIG. 11  is an isometric view, showing the modified extension tube locked into the modified spray cap.  
       REFERENCE NUMERALS IN THE DRAWINGS  
       [0020]    
       
         
               
               
               
               
               
             
           
               
                   
                   
               
               
                   
                   
               
             
             
               
                   
                 10 
                 aerosol can 
                 12 
                 spray cap 
               
               
                   
                 14 
                 nozzle insert 
                 16 
                 orifice 
               
               
                   
                 18 
                 extension tube 
                 20 
                 T-cap 
               
               
                   
                 22 
                 cross slot 
                 24 
                 T-tube 
               
               
                   
                 26 
                 conduit 
                 28 
                 orifice 
               
               
                   
                 30 
                 locking block 
                 32 
                 first mating surface 
               
               
                   
                 34 
                 second mating surface 
                 36 
                 inlet 
               
               
                   
                 38 
                 tube 
                 40 
                 gasket insert 
               
               
                   
                 42 
                 threaded cap 
                 44 
                 threaded counterbore 
               
               
                   
                 46 
                 threaded tube 
                 48 
                 threaded shank 
               
               
                   
                 50 
                 threaded extension 
                 52 
                 delivery tube 
               
               
                   
                 54 
                 spray slot 
                 56 
                 boss 
               
               
                   
                 58 
                 extension tabs 
                 60 
                 tube tabs 
               
               
                   
                 62 
                 mating surface 
                 64 
                 inclined surface 
               
               
                   
                 66 
                 inclined surface 
                 68 
                 detent 
               
               
                   
                 70 
                 mating surface 
                 72 
                 ridge 
               
               
                   
                   
               
             
          
         
       
     
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]      FIG. 2  shows T-cap  20  and T-tube  24 . T-cap  20  generally assumes the same shape as prior art spray cap  12 . However, a pair of intersecting slots are cut into its upper surface. These are cross slot  22  and spray slot  54 . These two slots combine to form a “T” shape, hence the name T-cap  20 . A modified type of extension tube is configured to mechanically interlock with the two slots. The view shows T-tube  24  in position to be installed.  
         [0022]      FIG. 3  shows T-cap  20  sectioned in half. It is shown just above the position it would normally occupy when installed on aerosol can  10 . Although the particular method of installing T-cap  20  on aerosol can  10  is not significant to the present invention, those skilled in the art will know that one good method of installing such a cap is to press the lower portion of conduit  26  over delivery tube  52 .  
         [0023]     Delivery tube  52  remains in aerosol can  10 . When it is pressed downward, the contents of the can are delivered through the hollow interior of delivery tube  52 . When T-cap  20  is installed, the can&#39;s contents are delivered through conduit  26 , eventually emerging through orifice  28 . Orifice  28  is actually located in the rear wall of cross slot  22 , which is designated as first mating surface  32  in  FIG. 3 .  
         [0024]     The reader will observe that spray slot  54  is aligned with orifice  28 . This fact is significant since the device preferably functions well without the use of an extension tube. In other words, the user preferably has the option of a diffused spray available without an extension tube, or a focused spray available with the extension tube. To that end, the side walls of spray slot  54  preferably diverge somewhat so as not to interfere with the spray pattern when T-tube  24  is not in use.  
         [0025]      FIG. 4  shows the portion of T-tube  24  which is configured to lock into T-cap  20  in more detail. Locking block  30  is a rectangular piece which is attached to the hollow tube  38 . Inlet  36  is located on second mating surface  34 . It passes through locking block  30  to connect with the hollow interior of tube  38 . The reader will observe by studying the geometry that when T-tube  24  is pressed into T-cap  20 , second mating surface  34  will mate snugly with first mating surface  32  (assuming that locking block  30  is properly sized with respect to cross slot  22 ). The height of locking block  30  is selected so that when its lower surface mates against the lower surface of cross slot  22 , inlet  36  will be aligned with orifice  28 . Tube  38  will then lie within spray slot  54 .  
         [0026]     Second mating surface  34  bears against first mating surface  32  so that when the user presses T-cap  20 , the contents of aerosol can  10  will flow from orifice  28  into inlet  36  without unwanted leakage. However, for certain low-viscosity solvents, the mating of the two surfaces alone maybe insufficient.  FIG. 5  shows the addition of gasket insert  40  to second mating surface  34 . Gasket insert  40  is preferably made of a pliable sealing material which helps form a tight seal between orifice  28  and inlet  36 . A sealing gasket can also be placed on T-cap  20 .  FIG. 5B  shows an alternate version of T-cap  20  in which a gasket insert  40  has been added around orifice  28 .  
         [0027]      FIG. 6  shows the completed assembly, with T-tube  24  mechanically locked to T-cap  20 . The reader will observe how locking block  30  rests within cross slot  22  and how tube  38  rests within spray slot  54 . In this configuration, the user may freely employ tube  38  without fear of it coming loose from T-cap  20 . The user is also free to use the can with a more conventional diffused spray by simply removing T-tube  24 . It easily presses into place and it is just as easily removed.  
         [0028]      FIG. 7  shows other mechanical interlocking means which can be used to lock the extension tube to the cap. Conduit  26  passes through threaded cap  42 , bends 90 degrees, and exits at a point on the cap&#39;s perimeter. Threaded counterbore  44  is provided at this point of exit. Threaded tube  46  is substituted for T-tube  24 . It has threaded shank  48 , which features a male thread sized to engage the female thread within threaded counterbore  44 . Inlet  36  passes through threaded shank  48  and connects to the hollow interior of the extension tube. In this embodiment, the user installs the extension tube by threading threaded shank  48  into threaded counterbore  44 , and removes it by unthreading threaded shank  48  from threaded counterbore  44 . Both components are shown sectioned in half in order to aid visualization.  
         [0029]     An alternate embodiment is shown in  FIG. 8 . Threaded extension  50  extends from the cap&#39;s perimeter at the point where conduit  26  exits. Threaded extension  50  features a male thread. An alternate embodiment of threaded tube  46  is also provided. In the version shown in  FIG. 8 , threaded shank  48  features a female thread along the wall of inlet  36 . This female thread is sized to engage the male thread on threaded extension  50 . Its operation is the same as for the embodiment shown in  FIG. 7 ; i.e., the user installs and removes the extension tube using the threaded engagement.  
         [0030]      FIG. 9 ,  FIG. 10 , and  FIG. 11  show another embodiment of the present invention. An alternative embodiment of threaded extension  50  and threaded shank  48  is also provided.  FIG. 9  shows threaded cap  42  with an alternate embodiment of threaded extension  50 . Boss  56  is affixed to threaded cap  42  around conduit  26 . Threaded extension  50  protrudes from boss  56  at the point where conduit  26  exits. Threaded extension  50  features extension tabs  58  which resemble partial turns of threading on opposite sides of threaded extension  50 . Extension tabs  58  feature inclined surface  64  on the side proximal to boss  56 .  
         [0031]      FIG. 9B  illustrates inclined surface  64  on extension tabs  58  from a different perspective. Inclined surface  64  features ridge  72  which allows extension tabs  58  to “lock” into place with the spray tube when the two are rotationally engaged.  
         [0032]      FIG. 10  shows threaded tube  46  with an alternate embodiment of threaded shank  48 . Inlet  36  is sized to receive threaded extension  50  of  FIG. 9 . Tube tabs  60  are sized and positioned within inlet  36  to engage extension tabs  58  when threaded cap  42  and threaded tube  46  are threadedly connected as shown in  FIG. 11 . Tube tabs  60  have inclined surface  66  that mates with inclined surface  64  when tube tabs  60  and extension tabs  58  are rotationally engaged. Inclined surface  66  is distal to mating surface  70  so that rotational engagement of tube tabs  60  and extension tabs  58  forces mating surface  70  against mating surface  62 . Tube tabs  60  also feature detent  68  at the peak of inclined surface  66 , thereby allowing ridge  72  of extension tabs  58  to snap into place. Once the ridges  72  are snapped into the detents  68 , the threaded tube is held securely in place.  
         [0033]      FIG. 11  illustrates the attachment of threaded tube  46  to threaded cap  42 . To attach threaded tube  46  and threaded cap  42 , threaded extension  50  is inserted into inlet  36  of threaded shank  48  so that mating surface  70  abuts mating surface  62 . Threaded shank  48  is then rotated approximately a quarter of a turn in the clockwise direction relative to boss  56 , thereby engaging extension tabs  58  with tube tabs  60 . To release threaded tube  46  from threaded cap  42 , threaded shank  48  is rotated approximately a quarter of a turn in the counterclockwise direction relative to boss  56 .  
         [0034]     The preceding description contains significant detail regarding the novel aspects of the present invention. It is should not be construed, however, as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. As an example, many shapes could be employed for cross slot  22 , spray slot  54  and locking block  30 . They are not limited to the orthogonal walls shown, but could instead be elliptical in shape. Such a variation would not alter the function of the invention. Thus, the scope of the invention should be fixed by the following claims, rather than by the examples given.