Abstract:
A detachable vial insert for a spirit level is disclosed comprising a casing defining a cavity for receiving a pair of semi-transparent liquid-filled vials having a longitudinal curvature containing a bubble for providing an indication of a true level plane when the bubble is positioned between two markings placed on the body of the vial. The vial insert may be used as a pre-calibrated stand-alone device or as a replaceable insert for a spirit level.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present nonprovisional application claims the benefit of U.S. Provisional Application No. 60/353,554 filed Jan. 31, 2002.  
           [0002]    1. Field of the Invention  
           [0003]    The present invention relates to spirit levels, and more particularly to a spirit level having detachable vial inserts. More specifically, the present invention relates to a pre-calibrated vial insert for a spirit level.  
           [0004]    2. Prior Art  
           [0005]    Spirit levels typically include a frame with parallel working surfaces having one or more apertures into which is installed are vials that provide an indicating means to determine if a surface is level. Each leveling vial has a transparent liquid-filled housing with a longitudinal curvature and opposed end portions that are bonded to each end of the apertures level body. A bubble is entrapped in the liquid in each vial for indicating true level when the bubble is located between a pair of indicating marks inscribed on each leveling vial. The indicating marks are positioned such that when the marks on a particular level vial are facing upwardly relative to a resting surface, the bubble will float to the upper inside surface of the leveling vial and be positioned between the marks, thereby indicating true level.  
           [0006]    Spirit levels have been constructed using various different arrangements for mounting the leveling vials directly in the frame of the spirit level. However, prior art spirit levels with detachable vials have several drawbacks. The vials previous devices require that the leveling vials be calibrated after being inserted into the apertures of the spirit level, thereby requiring that the spirit level be calibrated by some type of calibration mechanism after assembly. Further, none of the vials of the prior art are capable of being used as a stand-alone level device separate from the spirit level since each vial insert must be calibrated in conjunction with the spirit level.  
           [0007]    Therefore, there appears a need in the art for a spirit level having one or more detachable pre-calibrated vial inserts that may also be used as a stand-alone device for indicating true level. There is also a need in the art for a spirit level which contains vial inserts that are easily replaceable, thus making the spirit level easy to repair should it become damaged.  
         OBJECTS AND SUMMARY OF THE INVENTION  
         [0008]    Accordingly, the primary object of the present invention is to provide a vial insert that may be used as a stand-alone level device.  
           [0009]    Another object is to provide a vial insert that is pre-calibrated prior to assembly with a spirit level.  
           [0010]    A further object of thee present invention is to provide a spirit level requiring no calibration of the spirit level device itself after assembly is complete.  
           [0011]    Yet another object of the present invention is to provide a vial insert that is a single, complete level device.  
           [0012]    Another further object of the present invention is to provide a vial insert that is easily removable and repairable.  
           [0013]    Yet another further object of the present invention is to provide a method of constructing a vial insert so that it is completely calibrated prior to assembly with the spirit level.  
           [0014]    These and other objects of the present invention are realized in the preferred embodiment of the present invention, described by way of example and not by way of limitation, which provides for a spirit level having one or more vial inserts that are pre-calibrated and may read a level surface without attachment to the spirit level.  
           [0015]    In brief summary, the present invention overcomes and substantially alleviates the deficiencies in the prior art by providing a spirit level for attachment of one or more pre-calibrated vial inserts. The spirit level of the present invention comprises a frame having one or more apertures for receiving a respective vial insert that has been pre-calibrated and precision formed such that each insert can stand-alone and provide true level to the user without attachment to the frame.  
           [0016]    Each vial insert includes a housing defining a chamber that preferably encases a pair of level vials therein. Each level vial includes a casing which contains a predetermined amount of liquid with a bubble formed therein for indicating a true level plane. During calibration of the vial insert, a pair of marking lines are provided on the central portion of each casing for indicating true plane when the bubble is positioned between the two markings. The housing forms a pair of opposed holes that are adapted to receive the respective end portions of each level vial during assembly. Once the vial insert is properly positioned within the holes, the insert itself is calibrated by placing it on a surface having a true level plane and then adjusting the level vials relative to the housing so that the proper marking lines are made along the casing to indicate true level prior to permanently bonding the level vials to the housing. After the vial inserts are properly calibrated, each insert is placed in a respective aperture formed through the level spirit and a pair of lenses are secured to both sides of the housing so that the vial inserts are completely encased with the frame of the spirit level. The housing of each vial insert is precision machined so that a pre-calibrated vial insert can function as a stand-alone spirit level without being engaged to the level frame after assembly.  
           [0017]    Additional objects, advantages and novel features of the invention will be set forth in the description which follows, and will become apparent to those skilled in the art upon examination of the following more detailed description and drawings in which like elements of the invention are similarly numbered throughout. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    [0018]FIG. 1 is a perspective view of the spirit level according to the present invention;  
         [0019]    [0019]FIG. 2 is an exploded view of the spirit level according to the present invention;  
         [0020]    [0020]FIG. 3 a  is a cross-sectional view taken along line  3   a - 3   a  of FIG. 1 according to the present invention;  
         [0021]    [0021]FIG. 3 b  is a cross-sectional view taken along line  3   b - 3   b  of FIG. 1 according to the present invention;  
         [0022]    [0022]FIG. 4 is a perspective view of one embodiment of the vial insert according to the present invention;  
         [0023]    [0023]FIG. 5 is an end view of the embodiment of the vial level shown in FIG. 4 according to the present invention;  
         [0024]    [0024]FIG. 6 is a perspective view of another embodiment of the vial insert according to the present invention;  
         [0025]    [0025]FIG. 7 is an end view of an embodiment of the vial insert shown in FIG. 6 according to the present invention;  
         [0026]    [0026]FIG. 8 is a front view of one embodiment of a lens according to the present invention;  
         [0027]    [0027]FIG. 9 is a front view of another embodiment of a lens according to the present invention;  
         [0028]    [0028]FIG. 10 is an enlarged view of FIG. 2 according to the present invention; and  
         [0029]    [0029]FIG. 11 is another enlarged view of FIG. 2 according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0030]    Referring to the drawings, the preferred embodiment of the spirit level of the present invention is illustrated and generally indicated as  10  in FIG. 1. Spirit level  10  comprises a body  12  defined by top and bottom sides  54  and  56 , opposing sides  58  and  60 , and front and back sides  62  and  64  such that body  12  provides a true level surface. As shown in FIG. 2, body  12  further defines first, second and third apertures  48 ,  50  and  52  that are adapted to securely receive respective vial inserts  11 ( a ), ( b ) and ( c ) according to the present invention.  
         [0031]    Vial inserts  11 ( a ), ( b ), and ( c ) may be oriented at differing angles with respect to one another in one embodiment of the invention as depicted in FIGS. 1 and 2. In this embodiment, vial insert  11 ( a ) is oriented at a 90 degree angle with respect to vial insert  11 ( b ), while vial insert  11 ( c ) is at a 45 degree angle with respect to the vial insert  11 ( b ). As depicted in FIGS. 1 and 2, aperture  48  is at a 90 degree angle with respect to aperture  50 , thereby allowing vial insert  11 ( a ) in aperture  48  to determine plumness of an object, while vial insert  11 ( b ) can be utilized to determine whether or not an object was level. Aperture  52  is oriented at a 45 degree angle with respect to aperture  50 , thus allowing the vial insert  11 ( c ) to determine the level of an object set at a 45 degree angle. Alternatively, vial insert  11 ( c ) could be oriented with either vial insert  11 ( a ) or  11 ( b ) but the vials  216  and  218  would have to be set at a 45 degree angle with respect to vial insert  11 ( b ).  
         [0032]    Referring to FIGS.  3 ( a ) and  10 , aperture  48  and  52  are adapted to receive vial insert  11 ( a ) or  11 ( c ) and comprise a cavity  66  defining a pair of first shoulders  68  formed adjacent a pair of raised second shoulders  70  with a raised portion  172  interposed between shoulders  70 . As illustrated in the FIG. 1, aperture  52  has the exact same configuration as aperture  48  with respect to the means that secure the vial insert to body  12 . However, the angular orientations of vial inserts  11 ( a ), ( b ), and ( c ) may differ as described above in one embodiment of the invention. As shown in FIGS.  3 ( b ) and  11 , aperture  52  is sized and shaped to receive the larger vial insert  11 ( b ) and comprises a cavity  166  defining a pair of first shoulders  168  formed adjacent a pair of raised second shoulders  170  with a raised portion  72  interposed therebetween.  
         [0033]    Referring to FIG. 4, vial inserts  11 ( a ) and ( c ) have generally rectangular configurations with chamfered or beveled edges comprising a housing  14  defined by a top and bottom portions  20  and  22 , opposing side portions  24  and  26 , and front and back portions  34  and  35 . As shown in FIG. 4, both front and back portions  34  and  35  form a plurality of holes  36  along each side of housing  14  (FIG. 5) adapted to receive screws  41  (FIG. 3A) for securing respective first and second lens  40  and  42  to housing  14  during assembly. Opposing side portions  24  and  26  form opposing first and second openings  37  and  39  which are sized and shaped to receive respective end portions  33  of first and second vials  16  and  18 . Preferably, first and second vials  16  and  18  each have a casing  15  filled with a fluid  28  containing a bubble  30  for indicating a level plane. The casing  15  has a longitudinal curvature formed between end portions  33  that are bonded to respective openings  37  and  39  formed on opposing sides  24  and  26  as shall be explained in greater detail below. A pair of markings  32  are provided along a central portion of first and second vials  16  and  18  such that bubble  32  lies between markings  32  of one of the vials  16  or  18  when housing  14  is placed on a true level plane.  
         [0034]    Referring to FIG. 8, lens  40  is identical to lens  42  which collectively seal casing  15  when vial inserts  11 ( a ) and  11 ( b ) are securely engaged with spirit level  10  during assembly. Lens  40  includes a durable, transparent body having a generally rectangular shape substantially similar to the configuration of casing  15  having holes  46  formed therethrough along all four sides of lens  40 . Holes  46  correspond directly to holes  36  formed through housing  14  such that screws  41 , or other suitable means of attachment, may secure lens  40  and  42  to opposite sides of casing  15  when installing vial inserts  11 ( a ), ( b ), and/or ( c ) to spirit level  10 .  
         [0035]    Referring to FIGS. 6 and 7, vial insert  11 ( b ) is substantially similar to vial insert  11 ( a ) except insert  11 ( b ) has a longer rectangular configuration. Vial insert  11 ( c ) is identical to vial insert  11 ( a ) and only differs with respect to either its angular orientation to vial insert  11 ( b )or the vials  216  and  218 &#39;s angular orientation relative to vial insert  11 ( b ). As shown, vial insert  11 ( b ) comprises a housing  114  defined by a top and bottom portions  120  and  122 , opposing side portions  124  and  126 , and front and back portions  134  and  135 . Both front and back portions  134  and  135  form a plurality of holes  136  along each side of housing  114  adapted to receive screws  41  for securing respective first and second lens  140  and  142  to housing  114  during assembly. Vial insert  11 ( b ) also forms first and second openings  137  and  139  which are sized and shaped to receive respective end portions  133  of first and second vials  116  and  118 .  
         [0036]    Similar to vial insert  11 ( a ) and ( c ), first and second vials  116  and  118  each have a casing  115  filled with a fluid  28  containing a bubble  30  for indicating a level plane. Casing  115  has a longer longitudinal curvature than casing  15  such that the lengths of first and second vials  116  and  118  are substantially similar to the length between opposing side portions  124  and  126 . A pair of markings  32  are also provided along the central portion of casing  115  such that bubble  30  is positioned between the markings  32  when vial insert  11 ( b ) is placed on a true level plane.  
         [0037]    Referring to FIG. 9, lens  140  and  142  are substantially similar to lens  40  and  42  with the exception that lens  140  and  142  are configured larger to properly fit with casing  115 . Lens  140  and  142  also include holes  146  which correspond directly with holes  136  of casing  115  when lens  140  and  142  are engaged to casing  115  using screws  41 , or other suitable means of attachment.  
         [0038]    To assemble and pre-calibrate vial inserts  11  ( a ), ( b ), and or ( c ), (each vial insert is assembled in a identical manner; however, for simplicity sake, only insert  11 ( a ) will be discussed below but this same process could be utilized for any of the vial inserts  11  ( a ), ( b ), and or ( c )) the user performs the task with the aid of a true level surface known in the art, which is preferably constructed of granite (not shown) housed in a steel table with adjustable legs (not shown). Before the user may begin the assembly process for the vial insert  11  ( a ) the granite working surface must be shown to be true level. A completed and calibrated leveling device is used to determine whether or not the granite working surface is at true level. Should the granite working surface not be level, the adjustable legs of the table should be adjusted by known methods in the art, such as by utilizing an Allen® wrench, to raise or lower the legs of the metal table to achieve a level surface on which to construct vial insert  11 ( a ).  
         [0039]    After the granite working surface is level, the vial insert housing  14  is placed on the granite working surface so that top and bottom portions  20  and  22  are parallel with the granite working surface. During this stage of the assembly, opposing side portions  24  and  26  should be perpendicular with the granite working surface.  
         [0040]    To assemble vial insert  11 ( a ), vial  18  is fully inserted through either opening  37  or  39  until it is fully disposed inside chamber  19  and anchored between openings  37  or  39 . To properly position the vial  18  within housing  14 , lines  32  should each be of equal distance from side members  26  and  28  respectively. If vial  18  not seated properly in openings  37  or  39 , a shim can be utilized to help secure vial  18 . This shim can be constructed of materials such as aluminum foil and should be placed between vial  18  and the surface that vial  18  contacts along side members  26  and  28 . In the preferred embodiment, aluminum foil is used as the material for the shim as it is constructed from a material that is similar to what the insert is constructed of. Furthermore, aluminum is compatible with a UV light source used to cure the adhesive as described below.  
         [0041]    After vial  18  is placed in vial insert  11  ( a ) it must be made level with respect to housing  12 . This is accomplished by adjusting vial  18  such that bubble  30  is exactly between lines  32 . The leveling of vial  18  is complete and the vial  18  must now be secured to vial insert  11 ( a ) permanently.  
         [0042]    The securing step is accomplished by placing an adhesive known in the art (not shown) on the ends of vial  18  whereby they come in contact with openings  37  or  39  along side portions  26  and  28 . Preferably, the adhesive is an ultra violate cure adhesive (not shown) that is compatible with the materials it will come in contact with and which requires the added step of utilizing an ultra violate light source (not shown) to cure the adhesive. This process is repeated until all of the desired vials are placed within the vial insert  11 ( a ) and properly calibrated to true level. This method can be repeated for any number of vial level inserts utilized with practicing the present invention, such as with vial insert  11  ( b ) or  11 ( c ).  
         [0043]    If the user wishes to use the vial insert  11 ( a ) as a stand-alone level, he or she may do so. However, in this embodiment, lenses  40  and  42  would not be attached to the vial insert  11 ( a ).  
         [0044]    If the user wishes to use the vial inserts  11 ( a ) or  11 ( c ) asor part of spirit level  10 , he or she may insert a vial insert  11 ( a ) and/or ( c ) into apertures  48  and/or  52 . Apertures  48  and  52  define precision machined cavities  66  that are shaped and sized to securely receive vial insert  11 ( a ) or  11 ( c ). As illustrated in FIG. 10, an O-ring or other suitable sealing means  38  is placed along the peripheral edge of either back or front portions  34  and  35  and one of the lens  40  or  42  secured to the side of casing  15  adjacent o-ring  38 . The casing  15  is then inserted into aperture  48  such that the lens  40  is made flush with the body  12  of spirit level  10  and the end portions  33  of first and second vials  16  and  18  are facing towards top and bottom sides  54  and  56  of spirit level  10 .  
         [0045]    For vial insert  11 ( c ), vials  216  and  218  may be diagonally aligned with top and bottom sides  54  and  56 , respectively, at a 45 degree angle, or alternatively, one could simply place vial insert  11 ( c ) with vials  216  and  218  oriented in the same position as vials  16  and  18  at a 45 degree angle within body  12 . The assembly of vial insert  11 ( a ) is completed when the other O-ring  38  is placed along the peripheral edge of casing  15  and the other lens  40  or  42  is secured to casing  15  by screws  41  or other securing means so that the vial insert  11 ( a ) is fully attached to spirit level  10  through aperture  48 . In this arrangement, O-rings  38  rest against second shoulders  70 , while lens  40 ,  42  contact first shoulders  68   
         [0046]    Referring to FIG. 11, the assembly of vial insert  11 ( b ) into aperture  50  is performed substantially in the same manner as vial insert  11 ( a ), except that insert  11 ( b ) is oriented such that the end portions  33  of first and second vials  16  and  18  face toward opposing sides  58  and  60  of spirit level  10 . The casing  115  is then inserted inside aperture  50  and lens  140  or  142  secured to the casing  115  as discussed above. Again, in this arrangement, O-rings  138  contact second shoulders  70 , while lens  140  or  142  rest against first shoulders  168 .  
         [0047]    The present invention contemplates that apertures  48  and  52  could be adapted to receive vial insert  11 ( b ) and aperture  50  adapted to receive inserts  11 ( a ) or  11 ( c ), or all three apertures  48 ,  50  and  52  could be adapted to receive just one type of vial insert or any arrangement of vial inserts  11 ( a ), ( b ), or ( c ).  
         [0048]    Preferably, body  12  is made from a durable wood, plastic, aluminum, or fiberglass; however, it is within the spirit and scope of the present invention that body  12  could also be made from a suitable metal, such as stainless steel or the like. Further, it is preferable that lens  40 ,  42  and  140 ,  142  be made from a glass or a transparent plastic material, such as plexiglass, which provides suitable protection to first and second vials  16 ,  18 ,  116 ,  118 , and  216 ,  218 . Similarly, first and second vials  16 ,  18 ,  116 ,  118  and  216 ,  218  can be made of a durable glass or a semi-transparent plastic material. Casings  15  and  115  are preferably made from a precision machined metal (e.g., brass, aluminum, anodized metals, plastics or phenolic materials) that is configured to provide a true level plane.  
         [0049]    Preferably, first and second vials  16 ,  18 , and  216 ,  218  are 8mm×30 mm bent tubular vials, while first and second vials  116  and  118  are 8 mm×2⅜ inches bent tubular vial.  
         [0050]    An example of preferred dimensions for spirit level  10  might be a height of 2.4375 inches and a depth of 1.0625 inches. Also preferably, apertures  48  and  52  might have a height of 1.502 inches and a length of 1.752 inches, while aperture  50  may have a height of 1.502 inches and a length of 2.752 inches. First shoulders  66  and  166  and second shoulders  68  and  168  have the same heights even though the lengths may vary between embodiments of vial inserts ( a ), ( b ), and ( c ). For example, first shoulders  66  and  166  have a height of 0.5 inches, while second shoulders  68  and  168  have a height of 0.058 inches. However, the present invention contemplates that spirit level  10  may have other alternative dimensions. Furthermore, in a preferred embodiment the user may attach protective metal plates along the corners of the spirit level  10 .  
         [0051]    An example of preferred dimensions of the lens  40  and  42  would be a height of 1.470 inches and a length of 1.730 inches. Casing  15  may preferably have a height of 1.240 inches and a length of 1.50 inches, while the alternate embodiment, casing  115 , may have a height of 1.240 inches and a length of 2.50 inches. Finally, O-rings  38  and  138  are configured to securely engage the peripheral edge of respective casings  15 ,  115  as shown in FIGS. 10 and 11.  
         [0052]    It should be understood from the foregoing that, while particular embodiments of the invention have been illustrated and described, various modifications can be made thereto without departing from the spirit and scope of the invention. Therefore, it is not intended that the invention be limited by the specification; instead, the scope of the present invention is intended to be limited only by the appended claims.