Abstract:
An apparatus and method for configuring the angular alignment of a device or apparatus, such as a table saw blade. Specifically, the present invention includes a housing unit containing a light source for generating an optic marker, preferably a planar beam, a mechanism by which the housing unit is attached to the apparatus to be aligned, and a scaled protractor for calculating the angular relationship in degrees.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/055,047, entitled “ALIGNMENT APPARATUS AND METHOD OF USING SAME,” filed Aug. 8, 1997 which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to the field of alignment systems, and, more particularly to alignment systems that use optics to define an alignment reference. 
     Today, many common power tools found in a hobbyist&#39;s workshop or basement as well as production type commercial tools come with some type of alignment guides for assisting the operator in using the tool at a desired angle. Depending on the expense of the tool, many of these alignment guides can be relatively crude requiring the operator to expend substantial time in developing a “custom” system for calculating angles and performing an alignment, such as aligning a table saw blade to make an angled cut. It is not uncommon for several practice cuts to be made before an accurate alignment is obtained. 
     The art is filled with examples of apparatus for aligning power tools to perform a variety of operations. For example, U.S. Pat. No. 5,121,554 to Havins discloses a miter gauge apparatus for use with conventional power saws. Havins&#39; invention uses a protractor and a set of gages positioned about the radius of the protractor to position the saw blade physically at the correct cutting angle. A variable angle protractor is disclosed in U.S. Pat. No. 4,779,354 to Hill in which the protractor includes a reference base and a pivoting member that engages the apparatus to be aligned and moves in concert therewith to establish a desired angle of alignment. 
     Because of the accuracy of laser optics, several alignment systems incorporate an optic component that defines a target for the tool. U.S. Pat. No. 5,446,635 to Jehn discloses a laser assembly that projects a line of light onto a workpiece to guide a cutting instrument. Similarly, U.S. Pat. Nos. 5,285,708 and 5,375,495 to Bosten et al. disclose miter saws that use a laser to project an alignment marker on the workpiece to guide the blade. 
     U.S. Pat. No. 5,539,990 to Le and U.S. Pat. No. 5,594,993 to Tager et al. disclose instruments incorporating a laser for projecting reference lines for use as an alignment guide. Nevertheless, these instruments do have their shortcomings, particularly in aligning the reference line with the horizontal or vertical axis. Specifically, Le uses a plumb and support system to achieve a precise alignment with the vertical axis. Because Le&#39;s instrument must be positioned in a way that allows the plumb to hang properly, it may not be suitable for some applications in which the instrument cannot be oriented in the required configuration. The hand-held builder&#39;s tool disclosed by Tager et al. uses either a screw-thread mechanism or a cam-operated mechanism to align the reference line with a reference axis or plane. 
     While these inventions are useful for their intended purposes, they often require extensive modifications to existing equipment. Moreover, when the optic marker is projected onto the workpiece, the tool itself can sometimes obscure the marker as the tool engages the workpiece. This can result in a loss of accuracy as the operator attempts to align the operative component of the tool with the optic marker. Mechanisms used to calibrate the optic marker with a reference axis or plane have limited the applications in which the alignment apparatus can be used or require the use of a tool to carry out the calibration. 
     Accordingly, there exists a need for an alignment apparatus that is both versatile (i.e., can be used with multiple types of tools, machines, or other devices), and uses laser optics to perform the alignment of the apparatus apart from the workpiece. It is further desired that the alignment apparatus be capable of calibration with respect to a reference axis or plane without requiring additional tools. 
     SUMMARY OF THE INVENTION 
     Certain advantages and novel features of the invention will be set forth in the description that follows and will become apparent to those skilled in the art upon examination of the following or may be learned with the practice of the invention. 
     To achieve the advantages and novel features, the present invention is generally directed to an apparatus and method for configuring the angular alignment of a device or apparatus, such as a table saw blade. Specifically, the present invention includes a housing unit containing a light source (e.g., a laser) for generating an optic marker, preferably a planar beam, means by which the housing unit is attached to the apparatus to be aligned (e.g., the saw blade), and a scaled protractor for calculating the angular relationship in degrees. 
     In accordance with an aspect of the present invention, a magnet is used to mount the housing unit to the apparatus to be aligned thus providing a flexible attachment mechanism requiring no tools or additional parts. 
     In accordance with another aspect of the present invention, the protractor has degree markings on both sides. On one side, the degree markings occur every 11.25°, which is a common measurement in woodworking. On the other side, the degree markings occur every 1° as is customary in a traditional protractor. Moreover, the protractor is a separate component in the alignment system and can be positioned either horizontally or vertically in relation to a reference plane for performing compound alignments. 
     In accordance with yet another feature of the present invention, the housing unit includes means for attaching the unit to a support where the light beam can be aimed to produce an optic marker for use as a general purpose reference. One or more levels are attached to the housing to align the optic marker by assessing the conformity of the housing with respect to the horizontal and/or vertical axes. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     Other features of the present invention will be more readily understood from the following detailed description of specific embodiments thereof when read in conjunction with the accompanying drawings, in which: 
     FIGS. 1A and 1B provide perspective views of an optic marker housing unit according to the present invention; 
     FIGS. 2A and 2B illustrate a protractor for use with the housing unit of FIGS. 1A and 1B; 
     FIG. 3 illustrates the housing unit and protractor of FIGS. 1A,  1 B,  2 A, and  2 B used to align a table saw blade for a 90° cut; 
     FIG. 4 illustrates the housing unit and protractor of FIGS. 1A,  1 B,  2 A, and  2 B used to align a table saw blade for a 45° cut; and 
     FIG. 5 illustrates the housing unit and protractor of FIGS. 1A,  1 B,  2 A, and  2 B used to align a table saw blade for a compound miter cut. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While the invention is susceptible to various modifications and alternative forms, a specific embodiment thereof is shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the claims. 
     Referring now to FIGS. 1A and 1B, two perspective views of an optic marker housing unit  20  according to the present invention are shown. Housing unit  20  is manufactured from a suitable rigid material, such as aluminum, steel, plastic or other polymer material. The geometry of housing unit  20  should be chosen so that it will accommodate a laser or light source  22 , a battery (not shown), and a switch  24 . In the preferred embodiment, laser  22  operates on a low voltage power supply, such as a battery, and projects a line for use as an optic marker. Switch  24  is used to turn laser or light source  22  on and off. 
     Suitable means should be chosen to attach the housing unit to the apparatus to be aligned. For metallic apparatus, magnets  26  as shown in FIGS. 1A and 1B are preferred as they provide both a secure attachment mechanism and great versatility in locating the housing unit on the apparatus. In the embodiment shown, all three sides  28 ,  32 , and  34  include a recessed magnet for maximum versatility in positioning housing unit  20  on a host apparatus. Alternative means, including additional structure, such as clips, slots, clamps or screws can be used for non-metallic apparatus. 
     To perform an alignment, housing unit  20  is attached to the apparatus to be aligned and laser or light source  22  is aimed towards a scaled protractor  36 , as illustrated in FIGS. 2A and 2B. On one side or face  38 , protractor  36  contains a 180° semi-circle with degree markings every 11.25° as shown in FIG.  2 A. This division is chosen because multiples of 11.25° are common angles in woodworking applications. Preferably, however, protractor  36  will include standard 1° markings about a semi-circle on its opposite side or face  42  as shown in FIG.  2 B. This double sided arrangement provides convenience for woodworking applications, and detail where accuracy and precision are paramount. 
     Protractor  36  further includes a mid-point  44  defined by two crossing lines at the center of the semi-circle. Lines extend from each degree marker towards mid-point  44  to facilitate the calculation of an angle on protractor  36 . 
     FIG. 3 illustrates the operation of housing unit  20  and laser or light source  22  with protractor  36 . In the example shown, housing unit  20  is attached to a table saw blade  46  via a magnet. Protractor  36  is positioned perpendicular to the table surface  48 , which serves as a reference plane for the alignment. Laser  22  is activated and an optic marker, in the form of line  52 , is projected onto protractor  36 . Protractor  36  is then positioned so that line  52  intersects mid-point  44  defined on the side or face  38  of protractor  36 . In this position, the line  52  projected onto protractor  36  indicates the angle of the saw blade  46  in relation to the reference plane, which in this case is table surface  48 . The operator will then reposition the angle of blade  46  while simultaneously watching the line  52  projected onto protractor  36  until the desired angle is reached. FIG. 4 shows saw blade  46  repositioned to cut at a 45° angle as indicated by line  52  on side  38  of protractor  36 . Once aligned, protractor  36  and housing unit  20  can be removed and a workpiece can be cut at the previously established angle. It should be appreciated that the alignment takes place apart from the actual operation on the workpiece, the disadvantages of which were discussed in the foregoing. 
     A second type of angular alignment is illustrated in FIG.  5 . Similar to FIG. 3, housing unit  20  is attached to a table saw blade  46 . The table surface  48  includes miter tracks or slots  54  in which miter attachment  56  is located. In this example, protractor  36  is positioned substantially planar with table surface  48 , which serves as the reference plane. By positioning protractor  36  with its mid-point  44  intersecting line  52  generated by laser  22  and its top edge flush against miter attachment  56  (or up against the workpiece as shown in FIG.  5 ), the operator can adjust miter attachment  56  until the line projected onto protractor  36  equals the desired angle. 
     By combining the alignment approach illustrated in FIG. 5 with the approach illustrated in FIGS. 3 and 4, apparatus can be aligned at compound angles. For example, in FIG. 5, saw blade  46  is initially aligned to cut at a 45° angle using the approach discussed hereinbefore with reference to FIGS. 3 and 4. Once this alignment is complete, the workpiece is aligned to receive saw blade  46  at a 45° angle as discussed previously with reference to FIG.  5 . 
     In addition to the alignment of apparatus discussed hereinbefore, the present invention can be used as a general purpose alignment guide or apparatus. With reference to FIGS. 1A and 1B, housing unit  20  contains one or two single axis levels  58  or a single dual axis level attached to its outer surface via suitable means. These levels  58  allow housing unit  20  to be leveled with respect to the horizontal and/or vertical axes. Advantageously, the operator can determine through a simple visual verification of levels  58  whether housing unit  20  is in proper calibration or alignment with the reference axes or planes without requiring any additional tools or complex calibration steps. 
     Housing unit  20  preferably contains apertures  62  drilled into its sides to allow housing unit  20  to be mounted to a support, such as the mounting post of a tripod or transit. In this configuration, the operator can select the desired orientation of housing unit  20  (i.e., angular, horizontal, or vertical) and laser or light source  22  will project an optic marker that can be used as a general purpose reference. For example, a reference line generated by laser  22  can be used for hanging drop ceilings, laying flooring materials, placing wall studs, installing dry wall, placing pipes and installing wall coverings. 
     In concluding the detailed description, it should be noted that it will be obvious to those skilled in the art that many variations and modifications may be made to the preferred embodiment without substantially departing from the principles of the present invention. All such variations and modifications are intended to be included herein within the scope of the present invention, as set forth in the following claims.