Abstract:
A measuring instrument comprising a frame and a plurality of measurement indicia. A power source is positioned inside a portion of the frame with a light source operatively connected to the power source. When a user presses down upon the frame, the light source is actuated, sending light throughout the frame and illuminating the measurement indicia, providing improved visibility for a user.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is directed generally to measurement instruments. More particularly, the present invention is related to measurement instruments that include a mechanism that permits a user to easily view the measurement indicia contained thereon.  
         BACKGROUND OF THE INVENTION  
         [0002]    Measurement instruments, such as protractors and rulers, are conventionally known and are used in a variety of fields and industries. In particular, protractors and rulers are frequently used by school children who are learning how to define and describe angular and linear measurements, in addition to drawing lines and shapes that incorporate the measurements.  
           [0003]    A conventional protractor or ruler includes a plurality of measurement indicia located on at least one side of the instrument. For example, a ruler often includes indicia to represent linear measurements in inches, centimeters, millimeters and/or other measurement quantities. Similarly, protractors may include both linear and angular measurements, with the angular measurements indicating the number of degrees from a zero degree line of reference.  
           [0004]    Because young school children often must use rulers, protractors and other instruments, to not only learn the basics of geometry, but also to understand how to measure the length and angles of certain objects, it is important that they are able to easily identify the particular indicia of measurement on these measurement instruments. In many prior art measurement devices, however, the measurement indicia can be difficult to identify with the naked eye, either because of the contrast between the indicia and the background surface or because certain indicia, such as millimeter markings, are too close together to be easily distinguished. Additionally, measurement instruments directed to school children often include an additional need to keep the student&#39;s interest. If a school-related product includes additional features which pique the student&#39;s interest, then the student will be more likely to continue learning how to use the instruments.  
         SUMMARY OF THE INVENTION  
         [0005]    It is therefore an object of the invention to provide an improved measurement instrument that more clearly delineates a plurality of measurement indicia on at least one surface of the instrument.  
           [0006]    It is another object of the invention to provide an improved measuring instrument that provides a plurality of measurement indicia that can be easily seen by a user.  
           [0007]    It is a further object of the invention to provide an improved measuring instrument that allows a user to view the measuring indicia with a high degree of accuracy in a relatively dark environment.  
           [0008]    It is still another object of the invention to provide an improved measuring instrument that provides for an increased level of interest in a young user.  
           [0009]    In accordance with these objects of the invention, a measuring instrument is provided comprising a frame and a plurality of measurement indicia. A power source is positioned inside a portion of the frame with a light source operatively connected to the power source. When a user presses down upon the frame, the light source is actuated, sending light throughout the frame and illuminating the measurement indicia, providing improved visibility for a user.  
           [0010]    These and other objects, advantages and features of the invention, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein like elements have like numerals throughout the drawings described below. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a perspective view of one type of measurement instrument according to one embodiment of the invention;  
         [0012]    [0012]FIG. 2 is a reverse perspective and exploded view of the measurement instrument of FIG. 1;  
         [0013]    [0013]FIG. 3 is a perspective view of a measurement instrument according to a different embodiment of the invention;  
         [0014]    [0014]FIG. 4 is a perspective and exploded view of the measurement instrument of FIG. 3;  
         [0015]    [0015]FIG. 5 is a front view of a measurement instrument according to another embodiment of the invention;  
         [0016]    [0016]FIG. 6 is a magnified view of a plurality of indicia according to one embodiment of the invention;  
         [0017]    [0017]FIG. 7 is a magnified perspective view of a single groove of one of the plurality of indicia;  
         [0018]    [0018]FIG. 8 is a front view of a single groove according to one embodiment of the invention;  
         [0019]    [0019]FIG. 9 is a front view of a single groove according to another embodiment of the invention;  
         [0020]    [0020]FIG. 10 is a front view of a single groove according to yet another embodiment of the invention; and  
         [0021]    [0021]FIG. 11 is a front view of a single groove according to still another embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    A measurement instrument in the form of a protractor is shown generally at  20  in FIGS. 1 and 2. The protractor  20  includes a base  22  integrally connected to an arc portion  24  at each end thereof. The protractor  20  also includes a front side  42  and a back side  44 . The arc portion  24  includes a plurality of indicia  26  include thereon or therein. In this particular embodiment of the invention, the indicia  26  mark the number of degrees of an angle that is defined from the edge of the base  22  to that particular portion of the indicia  26 . The plurality of indicia  26  can also mark measurements of linear distance (such as in inches, centimeters, etc.) and can also include lettering or ornamental designs. Instead of being imprinted on the protractor  20  or other instrument, the plurality of indicia  26  could be embossed on the appropriate surface. Alternatively, the front side  42  of the protractor  20  (or other instrument) could include “raised” surface that correspond to the plurality of indicia  26 . Other methods of placing the plurality of indicia  26  on the protractor  20  or other instrument are known in the art and could also be used in conjunction with the present invention.  
         [0023]    As shown in FIG. 2, the base  22  of the protractor  20  includes a cavity  28  within which at least one battery  30  may be placed. In one embodiment of the invention, two batteries  30 , each having a voltage of about 3 volts, are used, although a single battery or multiple batteries of other sizes and voltages may also be used. The at least one battery  30  is coupled to a light source  34 . The light source  34  is coupled to a sleeve  36  that partially surrounds the light source  34 . The light source  34  is positioned such that, when actuated, the light source  34  will emit light along or through a pathway  40  within the arc portion  24 . The light source  34  may comprise a light emitting diode (LED), although other types of light may also be possible. The at least one battery  30  is affixed to the inside of the cavity  28  at the base  22  by an adhesive tape  38  or similar bonding mechanism, which would be easily understood by those skilled in the art. The at least one battery  30 , the light source  34  and the sleeve  36  are covered by a battery cap  32 . In a preferred embodiment of the invention, the battery cap  32  substantially aligns with the base  22 , permitting the protractor  20  to rest flat upon a surface such as a worktable (not shown).  
         [0024]    The plurality of the indicia  26  may comprise a plurality of individual grooves  27  strategically positioned within the protractor  20  along the pathway  40 , as shown in FIGS. 6 and 7. The individual grooves  27  can be formed in a variety of shapes. For example, the individual grooves  27  can include an uneven or textured upper surface  29 , as shown in FIGS. 8 and 9. The uneven or textured upper surface  29  may comprise small ridges, grooves, or similar structures. In another embodiment of the invention, the upper surface  29  of each individual groove  27  can be smooth and rounded, as shown in FIGS. 10 and 11. Additionally, the side walls  31  of each of the grooves  27  can be substantially perpendicular to a flat surface upon which the protractor  20  rests, as shown in FIGS. 8 and 10. Alternatively, the side walls  31  could be positioned at an angle to the surface, as shown in FIGS. 9 and 11. Other variations could be incorporated into ones of the individual grooves  27 . As light from the light source  34  travels along or through the pathway  40 , the individual grooves  27  illuminates by the light. The result of this illumination is that the entire plurality of the indicia  26  are illuminated, providing the user with an easier manner to view the plurality of the indicia  26 .  
         [0025]    The operation of the protractor  20  is generally as follows. When a user desires to use the protractor  20 , the user places the back side  44  of the protractor  20  on a flat surface. The user presses firmly against the front side  42  of the protractor  20 . The pressure exerted on the battery cap  32  against the at least one battery  30  results in an activation of the light source  34 . The light source  34  transmits light along the pathway  40 , which subsequently illuminates the indicia  26  along the arc portion  24  of the protractor  20 . In an alternate embodiment of the invention, light emitted from the light source  34  may also illuminate indicia  26  along the base  22  of the protractor  20 . The illumination of the indicia  26  on the protractor  20  aids the user in identifying and differentiating the indicia  26  along the arc portion  24  of the protractor  20 .  
         [0026]    In one embodiment of the invention and as shown in FIG. 5, a lighting mechanism of the type described herein could be incorporated into the protractor  20  with a lever arm  80  which is coupled to the base  22 , wherein the lever arm  80  is rotatable about an axis that is substantially orthogonal to the base  22 . This axis runs substantially through the center point  82  of a zero degree line  84  on the base  22 . The lever arm  34  includes a straight edge  86  that, combined with the zero degree line  84  of the base  22 , describes an angle therebetween. The straight edge  86  of the lever arm  80  may intersect the indicia  26  on arc portion  24  of the protractor  20 , helping the user to precisely define an angle. Protractors of this type are described in detail in U.S. Pat. No. 5,113,590, issued to Shapiro, and U.S. application Ser. No. 09/723,597 (assigned to the assignee of the present application), and both of which are incorporated by reference.  
         [0027]    An additional embodiment of the invention is shown in FIGS. 3 and 4. A measurement instrument in the form of a ruler is shown generally at  50  in FIGS. 3 and 4. The ruler  50  includes a frame  52  with a front side  72  and a back side  74 . The frame  52  may include a plurality of metric unit indicia  54  and/or English unit indicia  56  imprinted thereon or formed therein. In one embodiment of the invention, the metric unit indicia  54  mark the number of centimeters and/or millimeters along a first edge  76  of the frame  52 , while the English unit indicia  56  mark the number of inches and fractions of inches along a second edge  78  of the frame  52 . The English unit indicia  56  and the metric unit indicia  54  can comprise a plurality of grooves  27 , as shown in FIGS.  6 - 11  and described above.  
         [0028]    As shown in FIG. 4, the back side  74  of the frame  52  of the ruler  50  includes a cavity  58  within which at least one battery  60  may be placed. In one embodiment of the invention, a pair of batteries  60 , each having a voltage of about 3 volts, are used, although a single battery or multiple batteries of other sizes and voltages may also be used. The at least one battery  60  is coupled to a light source  64 . The light source  64  is coupled to a sleeve  66  that partially surrounds the light source  64 . The light source  64  is positioned such that, when actuated, the light source  64  will emit light through a pathway  70  within the frame  52 . The light source  64  may comprise an LED light, although other types of light sources may also be possible. The at least one battery  60  is affixed to the inside of the cavity  58  at the frame  52  by an adhesive tape  68  or similar bonding mechanism, which would be easily understood by those skilled in the art. The at least one battery  60 , the light source  64  and the sleeve  66  are covered by a battery cap  62 . In a preferred embodiment of the invention, the battery cap  62  substantially aligns with the frame  52 , permitting the ruler  50  to rest flat upon a surface such as a worktable (not shown).  
         [0029]    The operation of the ruler  50  is generally as follows. When a user desires to use the ruler  50 , the user places the back side  74  of the ruler  50  on a flat surface and presses firmly against the front side  72  of the ruler  50 . The pressure exerted on the battery cap  62  against the at least one battery  60  results in activation of the light source  64 . The light source  64  transmits light along the pathway  70 , which subsequently illuminates the metric unit indicia  54  and the English unit indicia  56  along the frame  52 . The illumination of the metric unit indicia  54  and the English unit indicia  56  on the ruler  50  aids the user in identifying and describing proper and accurate measurements.  
         [0030]    It should be understood that the above description of the invention and specific examples and embodiments, while indicating the preferred embodiments of the present invention, are given by demonstration and not limitation. For example, a variety of measurement instruments besides rulers and protractors could be developed for use with the present invention. Additionally, it is possible that the light source  64  could be actuated by methods other than simply pressing down upon the instrument. For example, the light source could be actuated with an on/off switch, or the light source  64  could be set to constantly provide a certain degree of light along the pathway. Many changes and modifications within the scope of the present invention may therefore be made without departing from the spirit thereof and the present invention includes all such changes and modifications.