| US 7,497,018 B2 | ||
| Laser-based alignment tool | ||
| William Hersey, 17 Bahr La., Corte Madera, Calif. 94925 (US); William H. Baylis, 4850 Paradise Dr., Tiburon, Calif. 94920 (US); and Yongxin Luo, 2559 47th Ave., San Francisco, Calif. 94116 (US) | ||
| Filed on May 26, 2006, as Appl. No. 11/442,003. | ||
| Prior Publication US 2007/0271800 A1, Nov. 29, 2007 | ||
| Int. Cl. G01C 15/00 (2006.01); G01B 11/26 (2006.01) | ||
| U.S. Cl. 33—286 [33/281; 33/DIG. 21] | 23 Claims |

| 1. An apparatus for projecting an indication of alignment, comprising:
a housing, wherein the housing is dimensioned such that the apparatus can fit within the palm of a human hand;
a projection unit pendulously suspended in the housing to project output beams to indicate level, plumb and square where the
projection unit includes a vertical projection module and a horizontal projection module and where each of the vertical and
horizontal projection modules include:
a laser emitting diode to emit a laser beam directly incident on a collimator, the collimator comprising a single lens,
the collimator configured to collimate the laser beam into a collimated beam and project the collimated beam on a planar reflective
surface;
a planar reflective surface orientated at an angle of approximately 45° to a path of the collimated beam projected from the
collimator and configured to divert the path of the collimated beam approximately 90° and toward a partial-conical reflective
surface;
a conical reflective surface formed from at least approximately 180° of an exterior surface of a cone and configured to reflect
the diverted collimated beam into an approximately 180° fanned output beam, where the conical reflective surface is positioned
relative to the planar reflective surface such that a center of the collimated beam is incident on a front face of the cone
and is not incident on the apex of the cone;
where the vertical projection module generates a substantially vertical output beam and the horizontal projection module generates
a substantially horizontal output beam, the vertical and horizontal output beams being projected from the housing in different
but generally perpendicularly related directions, whereby the output beams can be used to indicate level, plumb and square
alignment; and
a damper to dampen pendular motion of the projection unit.
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