Abstract:
A laser level disposable on a reference surface includes a housing, a pendulum pivotably connected to the housing, a first laser diode disposed on the pendulum for emitting a first laser beam along a first path, a first lens disposed on the pendulum in the first path for converting the first laser beam into a first planar beam, the first planar beam forming a first line on the reference surface, a second laser diode disposed on the pendulum for emitting a second laser beam along a second path, and a second lens disposed on the pendulum in the second path for converting the second laser beam into a second planar beam, the second planar beam forming a second line on the reference surface, wherein the first and second lines are substantially perpendicular and non-intersecting.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of U.S. application Ser. No. 10/643,382 filed on Aug. 19, 2003 now U.S. Pat. No. 7,031,367, which was a continuation-in-part of U.S. application Ser. No. 10/277,474, filed Oct. 22, 2002, now U.S. Pat. No. 6,914,930. 

   FIELD OF THE INVENTION 
   This invention relates generally to laser instruments and specifically to laser levels. 
   BACKGROUND OF THE INVENTION 
   Laser levels have been used in construction for many years. They typically seek to produce a plane of light for a reference for construction projects. Laser levels have been used for large scale construction projects like commercial excavating, laying foundations, and installing drop ceilings. Laser levels save considerable time during initial layout of a construction job compared to other tools such as beam levels, chalk lines, or torpedo levels. Some examples of jobs where laser levels would be useful include laying tile, mounting cabinets, installing counter tops, and building outdoor decks. 
   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 laser level is employed. The laser level disposable on a reference surface includes a housing, a pendulum pivotably connected to the housing, a first laser diode disposed on the pendulum for emitting a first laser beam along a first path, a first lens disposed on the pendulum in the first path for converting the first laser beam into a first planar beam, the first planar beam forming a first line on the reference surface, a second laser diode disposed on the pendulum for emitting a second laser beam along a second path, and a second lens disposed on the pendulum in the second path for converting the second laser beam into a second planar beam, the second planar beam forming a second line on the reference surface, wherein the first and second lines are substantially perpendicular and non-intersecting. 
   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 perspective view of a first embodiment of a laser level according to the invention; 
       FIG. 2  is a cross-sectional view of a second embodiment of the laser level according to the invention; 
       FIG. 3  illustrates a first wall hanging assembly for the laser level; 
       FIG. 4  is a partial cross-section of the laser level with a second wall hanging assembly; and 
       FIG. 5  illustrates an angle measuring device for use with the laser level. 
   

   DETAILED DESCRIPTION 
   The invention is now described with reference to the accompanying figures, wherein like numerals designate like parts.  FIGS. 1–2  show to two different embodiments of the invention. Persons skilled in the art will recognize that both embodiments have similar features, and that the main difference is the shape of the housing, which may provide advantages further discussed below. 
   Referring to  FIGS. 1–2 , a laser level  10  may have a housing  11 . The housing  11  may have a top portion  11 T and a bottom portion  11 B. The housing may also have a hole  12  extending through the housing  11 . The hole  12  preferably extends through the top portion  11 T. The perimeter of the hole  12  may be defined by an inner wall  11 I. 
   The top portion  11 T may carry a pendulum assembly  30 . Preferably, the pendulum assembly  30  has a main body  31 , which may be made of metal or plastic. Main body  31  may be disposed on a knife edge  11 IK. Knife edge  11 IK may be connected to and/or supported by inner wall  11 I. Alternatively, knife edge  11 IK may be connected to and/or supported by housing  11 . Persons skilled in the art will recognize that pendulum assembly  30  may be supported by means other than knife edge  11 IK, such as a pin, bearing, point or other pendulous means. 
   The main body  31  may carry at least one laser assembly  40  and preferably two laser assemblies  40  disposed above and right of the knife edge  11 IK. Persons skilled in the art will recognize that a laser assembly  40  may also be disposed left of knife edge  11 IK. Persons skilled in the art will also recognize that the laser assemblies  40  will emit laser beams. Accordingly, it is preferable to provide housing  11  with windows  13  to allow the laser beams to exit from housing  11 . 
   Preferably, the laser assemblies  40  are disposed on main body  31  to provide a self-leveling pendulum assembly that will emit substantially horizontal and substantially vertical laser beams when laser level  10  is disposed against a wall. It is preferable to align the laser assemblies  40  so that the center of hole  12  indicates the intersection of the laser beams. 
   Persons skilled in the art are directed to U.S. patent application Ser. No. 10/277,474, filed Oct. 22, 2002, which is fully incorporated herein by reference, for further information on how the elements within laser level  10  function, how they are calibrated, etc. 
   Referring to  FIGS. 1–2 , main body  31  may also have weights  33  to provide a lower center of gravity, and enhance the performance of the pendulum assembly  30 . In addition, main body  31  may have at least one adjustment screw  33 A to adjust the center of gravity of pendulum assembly  30 , as necessary. 
   Main body  31  may also have a plaque  33 M, made of magnetic material, ferrous material or non-ferrous conductive material, such as zinc or copper. Plaque  33 M preferably is aligned with at least one magnet (and preferably two magnets) disposed in housing  11 , e.g., on the inside of the front and rear walls of housing  11 , for providing a damping action on pendulum assembly  30 . Basically, eddie currents are generated within plaque  33 M, as the plaque moves and interacts with the magnetic field supplied by the magnet(s). 
   Persons skilled in the art shall recognize that pendulum assembly  30  is preferably wholly contained within housing  11 . However, the pendulum assembly  30  may be at least partly, if not completely, disposed outside of housing  11 . 
   Persons skilled in the art shall recognize that a damping mechanism for damping the motion of pendulum assembly  30  may be provided. Persons skilled in the art are directed to the damping mechanism disclosed in U.S. Pat. No. 5,144,487, which is wholly incorporated by reference herein, as well as to its equivalents. 
   The bottom portion  11 B of housing  11  may carry a battery  50  for powering the laser assemblies  40 . 
   Referring to  FIG. 23 , laser assemblies  40  are disposed on main body  31 . Laser assembly  40  may include a substantially cylindrical barrel  41 , which may be adjustably connected to main body  31 , laser diode  42  disposed in barrel  41 , and a line lens  43  disposed in barrel  41 . Persons skilled in the art will recognize that in the preferred embodiment, adjusting barrel  41  will result in moving laser diode  42  and line lens  43 . Preferably, line lens  43  converts the laser beam exiting laser diode  42  into a planar beam. In addition, persons skilled in the art will recognize that a collimating lens may be disposed between laser diode  42  and line lens  43 . 
   Referring to  FIG. 1 , with such arrangement, when laser level  10  is disposed against a wall W, laser assembly  40  will preferably emit a laser plane LP that contacts the wall W, forming a laser line LL on the wall. Persons skilled in the art will recognize that it is preferable to orient the laser assemblies  40  in such manner so that at least a portion of the laser plane LP will contact the wall W. In addition, persons skilled in the art will recognize that providing laser assemblies  40  on the pendulum assembly  30  discussed above will preferably result in laser level  10  projecting substantially horizontal and substantially vertical laser lines against the wall. 
   Referring to  FIG. 2 , laser level  10  may be provided with a locking assembly  50  to lock pendulum assembly  31  consistently in one position. Preferably, locking assembly  50  is combined with the switch actuator  51  which turns the laser assemblies  40  on and off. However, persons skilled in the art will recognize that locking assembly  50  may be separate from the switch or switch actuator  51 . 
   Switch actuator  51  may have an inclined or cam surface  51 C. Cam surface  51 C may contacts a lock  52 , and preferably contacts an inclined or cam surface  52 C of lock  52 . 
   Lock  52  is preferably pivotably attached to housing  11 . Lock  52  has a conical locking portion  52 P that can contact main body  31 . Preferably, main body  31  has a corresponding portion for contacting locking portion  52 P so that, when the two portions contact, the main body  31  cannot pivot. It is desirable to design the portions so that main body  31  is consistently and accurately locked in the same position every time locking portion  52 P contacts main body  31 . Main body  31  may carry an adjustment screw  54  for ensuring such consistent contact and locking action. 
   With such arrangement, lock  52  can be pivoted between a locking position where locking portion  52 P contacts main body  31 , and a bypassed position where locking portion  52 P does not contact main body  31 . Preferably, a spring  53  biases lock  52  towards the locking position. 
   A user can turn on the laser level  10  by moving switch actuator  51  upwardly. 
   If the user continues to move switch actuator  51  upwardly, cam surface  51 C will cause lock  52  to pivot in a counter-clockwise direction towards the bypassed position, thus unlocking pendulum assembly  30 . When the user wants to turn off the laser level  10  and/or lock the pendulum assembly  30 , the user need only to move the switch actuator  51  downwardly, as the spring  53  will move lock  52  towards the locking position. 
   Users may want to lock the pendulum assembly  30  (while laser assemblies  40  are still on) for several reasons. First, housing  11  may have at least one vertical reference surface  11 V, which is substantially parallel to the laser beam emitted by laser assembly  40  disposed above knife edge  11 IK and/or substantially perpendicular to the laser beam emitted by laser assembly  40  disposed right of knife edge  11 IK. Similarly, housing  11  may have at least one horizontal reference surface  11 H, which is substantially perpendicular to the laser beam emitted by laser assembly  40  disposed above knife edge  11 IK and/or substantially parallel to the laser beam emitted by laser assembly  40  disposed right of knife edge  11 IK. 
   Accordingly, if the pendulum assembly  30  is locked and the laser level  11  is placed against a wall WS, the laser level  10  will emit laser beams that are substantially parallel and perpendicular to the wall WS. 
   Users may also want to use laser level  10  to measure angles. Referring to  FIG. 5 , the laser level  10  may be disposed on an angle measuring assembly  60 . Angle measuring assembly  60  may have a body  61 , a post  62  on body  61  and a scale edge  63  on body  61 . Scale edge  63  may have angle indicia  63 I thereon. 
   To measure an angle, the laser level  10  may be rotatably disposed on post  62 . 
   The user would move the laser level  10  and angle measuring assembly  60  to the starting position. Preferably, the upward laser line will shine unto the scale edge. The user can then ensure that the laser line is at zero degrees. Then the user would rotate the laser level  10  (not the angle measuring assembly  60 ) to the desired end position. By reading the position of the laser line on the scale edge  63 , the user will know the angle between the starting and end positions. 
   It is preferable to provide laser level  10  with a means for hanging the laser level  10  on the wall. As shown in  FIG. 1 , laser level  10  may be hung by inserting a pin  19  through hole  12 . 
   Alternatively, a hanger assembly  70  may be used for hanging laser level  10 , as shown in  FIG. 3 . Hanger assembly  70  may have a main body  71  with a central hole  74  for receiving the head of a screw or nail hammered into a wall. Main body  71  may be made of a translucent material to facilitate location of a mark or nail. 
   Hanger assembly  70  may also have a post  72  extending rearwardly from main body  71 . Ribs  73  may be disposed between the main body  71  and post  72  to increase structural strength, etc. Post  72  may have a snap hook  74  thereon. Hook  74  may be made of a resilient or elastic material, so that, when it is moved, it returns to its original position. 
   To install the laser level  10  unto hanger assembly  70 , the user would need to dispose laser level  10  on post  72 . Preferably, laser level  10  has a cavity  11 C for receiving such post  72 . Laser level  10  may also have a tab  11 T to engage hook  74 , and thus retain hanger assembly  70 . In order to remove hanger assembly  70  from laser level  10 , the user need only press hook  74  downwardly to clear tab  11 T, allowing the user to pull out hanger assembly  70 . 
   An alternate hanger assembly  80  is shown in  FIG. 4 . Hanger assembly  80  may have a main body  81  with a pin  84  extending therefrom. Main body  81  may be made of a translucent material to facilitate location of a mark or nail. Hanger assembly  80  may also have a post  82  extending rearwardly from main body  81 . Ribs  83  may be disposed between the main body  81  and post  82  to increase structural strength, etc. 
   Preferably, post  82  will have a rearwardly-extending flange  82 F so that, when hanger assembly  80  is placed on the floor on flange  82 F, pin  84  will not extend substantially vertically. 
   With such construction, the user would press pin  84  unto the wall. Preferably, laser level  10  has a cavity  11 C for receiving post  82 . The user may then align cavity  11 C with post  82 , and move laser level  10  towards the wall, until ribs  83  stop further movement. When the user lets go of the laser level  10 , the laser level  10  may move downwardly slightly down under the force of gravity. Tab  11 T may contact post  82  and stop restrain further downward movement. 
   To disengage the laser level  10 , the user should raise it so that tab  11 T can bypass post  82 , allowing the user to pull out hanger assembly  80 . 
   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.