Laser compass

• US 5,142,788 A
• Filed: 05/17/1991
• Issued: 09/01/1992
• Est. Priority Date: 05/17/1991
• Status: Expired due to Fees

• Current Assignee: Miles D. Willetts
• Original Assignee: Miles D. Willetts
• Inventors: Willetts, Miles D.
• Primary Examiner(s): HAROIAN, HARRY
• Application Number:
  US07/702,595
• Time in Patent Office: 473 Days
• Field of Search: 33/227, 33/228, 33/DIG. 21, 33/27.01, 33/27.11, 353/42, 353/50, 353/98, 353/99, 353/15, 356/250, 362/259, 362/811, 362/86
• US Class Current: 33/227
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: Y10S 33/01 Magnetic

Abstract

A laser compass projects a laser beam along an axis. A mirror is rotated within a rotation plane perpendicular to the axis. The mirror is pivotally adjusted relative to the axis of the laser beam to reflect the laser beam at an angle "α". As the mirror rotates, the reflected laser beam is swept through an inverted cone having an apex at the point of intersection of the laser beam with the mirror, and having a base on whatever projection surface happens to be located above the laser compass (typically, a ceiling). The base of the cone defines a perfect circle on the projection surface. The radius "r" of the circle is governed by the distance "d" between the projection surface and the intersection of the laser beam with the mirror; and, by the angle α. The mirror pivot angle α required to yield a circle of desired radius "r" is given by the formula:

tan α=r/d

The circle projected onto the projection surface may be used as a template to construct an accurate, curved pattern on the projection surface, or as an aid in the building of cylindrical or conical-shaped structures.

Claims

1. A laser compass comprising:

(a) a laser light source for projecting a laser beam along an axis;

(b) a mirror;

(c) mirror rotating means for rotating said mirror within a rotation plane perpendicular to said axis, said mirror rotating means comprising;

(i) a rotatable mirror support;

(ii) first and second mirror support arms projecting upwardly from said mirror support;

(iii) drive means for rotatably driving said mirror support; and

,

(d) mirror pivoting means for pivoting said mirror relative to said axis, said mirror pivoting means comprising;

(i) a link member projecting through said mirror support;

(ii) pivotal coupling means for pivotally coupling one end of said link member to said mirror;

(iii) securing means for pivotally securing said mirror between said support arms; and

(iv) adjusting means coupled through said mirror support to an opposed end of said link member for adjustably displacing said link member relative to said mirror.

2. A laser compass as defined in claim 1, wherein said adjusting means comprises:

(a) a worm gear coupled to said link member;

(b) a first bevel gear rotatably coupled to said worm gear;

(c) a second bevel gear rotatably engaged with said first bevel gear; and

(d) manual rotation means coupled to said second bevel gear.

3. A laser compass as defined in claim 2, further comprising adjustable levelling means for adjusting the angle between said rotation plane and said axis to maintain said rotation plane perpendicular to said axis.