Abstract:
An indicator vial including a liquid and a colored gas that contrasts with the liquid to provide a highly visible drop or bubble within the vial. The color of the gas is selected to contrast significantly with the liquid. The color of the liquid and of indicia disposed on the exterior of the vial can be selected to further enhance the contrast between the gas and the liquid and/or the indicia, to enhance visibility of the indicator within the vial.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority from U.S. Provisional Patent Application Ser. No. 60/602,950 filed on Aug. 19, 2004, and incorporated by reference herein in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to an indicator vial such as for use in a tool or other device, and more specifically to an indicator vial including a pair of dissimilarly and contrastingly colored fluids.  
       BACKGROUND OF THE INVENTION  
       [0003]     Devices incorporating indicator vials, also commonly referred to as bubble vials or level vials, have long been utilized for determining the angle, pitch or slope of a surface or object relative to a predetermined plane. The operation of the indicator vial is predicated on the ability of a user using the device to determine the position of a bubble present within the indicator vial with respect to reference lines located on the vial in order to determine the orientation of a surface or object, as measured by the vial. To provide an accurate indication of the angle, pitch or slope of the surface or object, most indicator vials are formed to include an amount of a liquid disposed within a casing that is securable to the leveling instrument in a desired orientation. The liquid partially fills the casing to form an air bubble that is freely movable within the liquid. In order to aid the user in determining the angle, pitch or slope of the surface or object, on many occasions the liquid positioned within the vial is colored in order to provide a more distinct separation between the air bubble and the liquid in the indicator vial.  
         [0004]     However, because the air bubble located within the vial is necessarily clear or transparent, in some circumstances the separation between the liquid and the air bubble is difficult to read since the color of the liquid is viewed directly through the bubble. This can be particularly evident in low light conditions, in which the coloring of the liquid in the vial is not adequate to clearly define the line of separation between the liquid and the air bubble. In such conditions, it is difficult for the user to distinguish the air bubble from the liquid and obtain an accurate reading of the orientation of the object relative to the predetermined plane.  
         [0005]     As a result, it is desirable to develop a fluid-type indicator vial that has a high contrast between the indicator and the surrounding liquid, so as to ensure that the indicator is easily visibly distinguishable from the liquid to provide accurate readings as to the orientation of a surface or object.  
       SUMMARY OF THE INVENTION  
       [0006]     According to a primary aspect of the present invention, an indicator vial includes a body or casing formed of a generally transparent material, and separate amounts of two immiscible fluids disposed within the body or casing. One of the fluids present within the vial is a liquid, and the other fluid is a colored gas that forms a bubble or drop that floats in the liquid within the vial, due to a difference in density between the fluids. The color of the gas, which forms the indicator bubble or drop suspended within and surrounded by the liquid, is selected so as to contrast with the color of the liquid, so that the indicator bubble or drop is therefore easily visible from the exterior of the vial.  
         [0007]     Numerous other aspects, features and advantages of the present invention will be made apparent from the following detailed description taken together with the drawing figures. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The drawings illustrate the best mode currently contemplated of practicing the present invention.  
         [0009]     In the drawings:  
         [0010]      FIG. 1  is an isometric view of a representative tool, in the form leveling instrument, incorporating a dual fluid indicator vial constructed according to the present invention;  
         [0011]      FIG. 2  is an isometric view of the vial of  FIG. 1 ; and  
         [0012]      FIG. 3  is a cross-sectional view along line  3 - 3  of  FIG. 2 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0013]     With reference now to the drawing figures in which like reference numerals designate like parts throughout the disclosure, a leveling instrument or tool constructed utilizing the indicator vials of the present disclosure is indicated generally at  10  in  FIG. 1 . The tool  10  can take any desired or preferred shape, but in one embodiment is in the form of a level that includes an upper rail  12  joined to a lower rail  14  by a web  16 . The web  16  extends between the upper rail  12  and lower rail  14  in a manner that positions the upper rail  12  and lower rail  14  parallel to one another, in order to provide flat engaging surfaces that may be positioned on a surface or object (not shown) to determine the orientation of the surface or object relative to a predetermined plane, in a manner as is known.  
         [0014]     The web  16  also supports a number of indicator vials  18 ,  20  and  22  in various angular orientations with respect to the rails  12  and  14 . The vials  18 ,  20  and  22  are maintained in position on the web  16  by respective vial holding members  24 ,  26  and  28  secured to the web  16  at various locations along the length of the web  16 . The holding members  24 ,  26  and  28  can take any desired form, and can be formed integrally with or separately from the web  16 . The holding members  24 ,  26  and  28  are operable to secure the vials  18 ,  20  and  22 , respectively, to the web  16  in various predetermined orientations relative to rails  12  and  14 , in a manner as is known. Representatively, the vials may be positioned to measure the orientation of a surface or object relative to horizontal (level), plumb (vertical), or a predetermined angle therebetween, e.g forty five degrees.  
         [0015]     Looking now at  FIGS. 2 and 3 , the dual fluid indicator vial in accordance with the invention, such as vial  22 , includes a body or casing  30  that can be formed of any suitable fluid-impervious material, but is preferably formed of a hard plastic material, such as an acrylic, that is generally transparent, or that at least includes a generally transparent portion through which the interior  31  of the casing  30  can be viewed. The casing  30  can take any number of suitable shapes depending upon the construction of the web  16  and/or the holding members  24 ,  26  and  28 , but is preferably generally cylindrical in shape. The casing  30  is formed to include a closed end  32 , an open end  34  disposed opposite the closed end  32 , and a side wall  35  that extends between the closed end  32  and the open end  34 . The closed end  32  can be formed of a plug  36  secured to one end of the casing  30  by any suitable means, such as by sonic welding or a suitable adhesive, or can be integrally formed with the casing  30 . Furthermore, it is also contemplated that the casing  30  can be formed integrally with the web  16  or the holding member  24 ,  26  or  28 , where the web  16  or the holding members  24 ,  26  or  28  are formed of a suitable material that is transparent, is partially transparent, or that provides for the attachment of a transparent section thereto.  
         [0016]     The open end  34  of the casing  30  defines a recessed annular shoulder  38  located within the interior of the casing  30  on which rests a sealing cap  40 . The sealing cap  40  is preferably formed of a material similar to the material used to form the casing  30 , such that the cap  40  can be affixed over or within the open end  34  by any suitable means, such as an adhesive or by sonic welding, for example. The sealing cap  40  can be formed with an outer diameter  39  that is slightly less than the inner diameter of the casing  30 , such that the cap  40  rests completely within the casing  30  on the annular shoulder  38 . Alternatively, and as shown in  FIG. 3 , the cap  40  can have an outer diameter  39  essentially equal to that of the casing  30  and include a section  41  extending outwardly from the cap  40  into engagement with the shoulder  38 . In this embodiment, the cap  40  is sealed to the casing along the periphery of the cap  40  and along the periphery of the section  41 , to securely seal the open end  34  of the casing  30 . However, other alternative constructions for the casing  30  and the cap  40  are also contemplated as being within the scope of the invention.  
         [0017]     To assist in measuring the slope, pitch or angle of a surface or object on which the tool  10  is positioned, the casing  30  also includes indicia  42  disposed on the casing  30  between the closed end  32  and open end  34 . The indicia  42  is typically in the form of lines that define spaced apart rings on the casing side wall  35 . The indicia  42  may be printed on, adhered to or integrally formed with the casing side wall  35 , and can be located on the interior or exterior of the side wall  35 . The indicia  42  function to provide a visible range on the casing  30  that can be used to determine the orientation of the object or surface against which the tool  10  is placed, in a manner as is known in the art.  
         [0018]     Referring now to  FIG. 3 , the vial  22  contains an amount of a liquid, in the form of a liquid  44 , and an amount of a gas, in the form of a gas  46 . Liquid  44  partially fills the volume of the casing  30 , and gas  46  fills the remainder of the volume of the casing  30 . With this construction, gas  46  functions to form a drop or bubble within the interior  31  of casing  30 , which interacts with the indicia  42  to provide a visual representation as to the orientation of an object or surface, against which tool  10  is placed, relative to a predetermined plane, such as horizontal, vertical or an angled plane therebetween. The liquid  44  and the gas  46  can be introduced into the vial  22  in any suitable manner as is known in the art. In order to maintain the liquid  44  and gas  46  separate from one another, and thereby to ensure proper operation of the vial  22 , the liquid  44  and gas  46  are preferably selected to be completely immiscible with one another. The gas  46  is present in an amount that is less than the amount of the liquid  44 , such that the bubble or drop of gas  46  has a size similar to that known in the art. In addition to being completely immiscible with the liquid  44 , the gas  46  is also preferably selected such that the gas  46  has a density less than that of the liquid  44 , which results in the drop or bubble  50  formed by the gas  46  floating within the liquid  44  in any position of the vial  22 . In this manner, the drop or bubble  50  formed of the gas  46  interacts with the indicia  42  on the vial casing side wall  35  to indicate the orientation of the object or surface on which the vial  22  relative to the predetermined plane.  
         [0019]     In the present invention, the use of the gas  46  to form the bubble  50  provides certain benefits with regard to the construction of the vial  22 . For example, when vial  22  is exposed to elevated temperatures, the liquid  44  within the vial  22  expands. The presence of gas  46  within the interior of vial  22  accommodates such expansion of liquid  44 , in that gas  46  compresses under the pressure applied to bubble  50  by the expanding liquid  44 . Such compression of gas  46  prevents the expanded liquid  44  from applying pressure to the walls of vial  22 , which may otherwise result in breaking or otherwise damaging the vial  22 .  
         [0020]     The gas  46  is selected so as to be colored, either naturally or artificially, in contrast with the color of liquid  44 , so as to visually offset the bubble  50  formed by the gas  46  from the liquid  44 . This enables the bubble  50  formed by the gas  46  to more easily be seen in contrast to the liquid  44  and in contrast to the indicia  42 . Examples of gases that can be utilized as the gas  46  include various single component, or essentially pure gases such as nitrogen dioxide, tungsten hexafluoride, and chlorine. Each of these gases in relatively pure form has an inherent color that can offset the bubble  50  formed by the gas  46  from, in a preferred embodiment, a clear or lightly colored liquid  44 .  
         [0021]     While the invention has been shown and described with respect to a specific embodiment, it is understood that various alternatives and modifications are contemplated as being within the scope of the present invention. For example, and without limitation, while the invention has been shown and described in connection with a tubular vial, it should be understood that the invention may take any form in which a colored gas bubble floats in, or is suspended by, a contrastingly colored liquid medium and in which the gas bubble is viewed in order to provide an indication as to the orientation of an object or surface relative to a predetermined plane. This includes any type of tubular vial, such as a straight-walled vial as shown and described, or a pitch-type vial. It is also contemplated that the indicator vial of the invention may be incorporated into a block vial, a bullseye level indicator, etc. It is also contemplated that the gas/liquid characteristics may be selected so that the gas has a density greater than the liquid, so that the indicator droplet or bubble is positioned on the bottom of the vial. In addition, it is understood that the vial of the present invention is not limited for use on a level-type tool as shown, but may be used in any application in which conventional air bubble-type vials are employed, e.g. in other tool products, e.g. drills or the like, automotive applications such as for use in headlight leveling, recreational vehicle or trailer applications for positioning a vehicle or trailer in a level orientation, etc. It is also contemplated that any type of contrasting color scheme may be accomplished using the present invention, e.g. a light colored liquid and a dark colored gas, or a dark colored liquid and a light colored gas, and that various degrees of contrast may be obtained using such color combinations.  
         [0022]     Various alternatives of the present invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claming the subject matter regarded as the invention.