Abstract:
A tape measure includes a housing, a rule blade coilable within the housing, and a light plane generator disposed on the housing. The light plane generator may include a laser source for emitting a laser beam and a line lens in the path of the laser beam for converting the laser beam into a laser plane. Preferably, the laser plane intersects both the rule blade and a workpiece. The light plane generator may be pivoted about a horizontal axis and/or a vertical axis.

Description:
FIELD OF THE INVENTION 
   This invention relates generally to tape measures and more specifically to a tape measure in combination with a laser device. 
   BACKGROUND OF THE INVENTION 
   Tape measures are well known devices used to measure distances, and are helpful in marking distances. It is desired to provide a device that enables the user to measure and/or mark distances more accurately. 
   It is an object of the present invention to provide a laser level that is inexpensive and usable by the general public. 
   SUMMARY OF THE INVENTION 
   In accordance with the present invention, an improved tape measure is employed. The tape measure has a housing, a rule blade coilable within the housing, and a light plane generator disposed on the housing, the light plane generator including a laser source for emitting a laser beam and a line lens in the path of the laser beam for converting the laser beam into a laser plane. Preferably, the laser plane intersects both the rule blade and a workpiece. The light plane generator may be pivoted about a horizontal axis and/or a vertical axis. 
   Additional features and benefits of the present invention are described, and will be apparent from, the accompanying drawings and the detailed description below. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings illustrate preferred embodiments of the invention according to the practical application of the principles thereof, and in which: 
       FIG. 1  is a side view of a tape measure according to the invention; 
       FIG. 2  is a cross-sectional view along line A—A of  FIG. 1 ; 
       FIG. 3  shows the tape measure used with a bracket; 
       FIG. 4  shows the tape measure on a workpiece; 
       FIG. 5  shows the tape measure with an alternative bracket, where  FIGS. 5A–5B  illustrate the bracket in a first and second position, respectively, and  FIG. 5C  shows different installation alternatives for such brackets. 
   

   DETAILED DESCRIPTION 
   The invention is now described with reference to the accompanying figures, wherein like numerals designate like parts. Referring to  FIG. 1 , a tape measure  10  may have a housing  11 , an elongated flexible rule blade  12  (also known as a tape) which is carried on a controllable spring-biased reel assembly (not shown) disposed within housing  11 , and a blade locking mechanism (not shown) actuated by a blade locking actuator (not shown) for locking the elongated blade  12  into a desired position to prevent the blade  12  from being further extended from the housing and from being wound into the housing by the spring-bias of the reel assembly. Persons skilled in the art will recognize that details of any of the parts referred to above, as well as further information on such tape measure, can be found in U.S. Pat. No. 6,209,219, which is hereby wholly incorporated herein by reference. 
   The tape measure  10  may also have a light plane generator  20 . Referring to  FIGS. 1–4 , the light plane generator  20  preferably generates a plane of light LP so that, when tape measure  10  is placed on a workpiece W, the light plane LP contacts the workpiece W and/or the blade  12 , creating a light line LL thereon. Preferably, the light plane generator  20  has a housing  22 , a laser diode  23  disposed in the housing for generating a laser beam, a collimating lens  24  for collimating the laser beam, and a line lens  25  for converting the laser beam into a laser light plane LP. Line lens  25  may be a cylindrical lens. 
   This assembly is preferably pivotally connected to an L-shaped neck  21 , which may be pivotally attached to housing  11 . Accordingly, a user can adjust the light plane generator about a horizontal axis HA and/or a vertical axis VA. 
   Light plane generator  20  may also include a battery  30  for powering the laser diode  23 . Battery  30  may be disposed in housing  11  or housing  22 . Light plane generator  20  may also include a switch  31  for turning laser diode  23  on and off. Switch  31  may be housing  11  or housing  22 . 
   It is preferable to provide a detent system for enabling the user to quickly locate the most common positions of the neck  21  (and thus light plane generator  20 ) relative to housing  11 . Accordingly, neck  21  may have detent notches  27  that receive a ball  26 , which is biased towards neck  21  by a spring  28 . Persons skilled in the art will recognize that detent notches  27  and ball  26  may also be provided on housing  11  and neck  21 , respectively. 
   It may be preferable to place tape measure  10  on a bracket  40 . Bracket  40  may include a U-shaped body  41  for receiving tape measure  10  and a flange  42  extending downwardly. With such arrangement, the user can place flange  42  against an edge of workpiece W, thus mounting tape measure  10  at the periphery of the workpiece W. Persons skilled in the art will recognize that bracket  40  can be disposed on tape measure  10  in two positions: with the flange  42  on the left side (shown in solid lines in  FIG. 3 ); and with the flange  42  on the right side (shown in broken lines in  FIG. 3 ). 
   With such arrangement, the user can place the tape measure  10  on bracket  40 , place both on workpiece W, pull blade  12  and hook the edge of workpiece W with tab  13 . The user can then turn on the light plane generator  20  by moving switch  31 . Light plane generator  20  then generates a light plane LP which creates a light line LL on workpiece W. The user can rotate housing  22  about the horizontal axis HA so that the light plane LP also lights blade  12 . Accordingly, light line LL will show on both blade  12  and workpiece W. If desired, the user can rotate light plane generator  20  about vertical axis VA to change the angle of light line LL relative to blade  12 , as shown in broken lines in  FIG. 4 . 
   Persons skilled in the art will recognize that, in the embodiment shown in  FIG. 4 , the light line LL extends rightwardly from blade  12 . However, the user need only rotate housing  22  about the horizontal axis HA in order for light line LL to extend leftwardly from blade  12 . 
   Persons skilled in the art will recognize that other brackets may be used with tape measure  10 . Referring to  FIG. 5 , tape measure  10 . Referring to  FIG. 5 , a bracket  50  may be disposed on tape measure  10 . Bracket  50  may include a flange  51  which is pivotably attached to housing  11  via shaft  52 . This would allow the user to rotate the flange  51  between a first position where the flange  51  does not contact workpiece W (shown in  FIG. 5A ) and a second position where the flange  51  contacts an edge of workpiece W (shown in  FIG. 5B ). 
   As shown in  FIG. 5C , bracket  50  may be separable from housing  11  and inserted on the other side thereof. This would allow the user to move the bracket  50  to contact a different edge of workpiece W, etc. Alternatively, housing  11  may carry two brackets  50  non-removably and rotatably attached to housing  11 . 
   Persons skilled in the art may recognize other additions or alternatives to the means disclosed herein. However, all these additions and/or alterations are considered to be equivalents of the present invention.