Geometrical instruments – Straight-line light ray type – Alignment device
Reexamination Certificate
2002-02-27
2004-02-24
Fulton, Christopher W. (Department: 2859)
Geometrical instruments
Straight-line light ray type
Alignment device
C033S227000, C033SDIG002
Reexamination Certificate
active
06694629
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns optical layout or measuring equipment, and in particular encompasses a laser projector tool mounted on or placed against a surface, that produces intersecting lines on that surface without moving parts to project the lines, and with a visible line intersection displaced from the instrument housing, for more convenient use.
Laser-projecting instruments are well known in the field of surveying and construction layout and as measuring devices. Prior patents show several examples of such tools that project lines, primarily by rotating a beam to make an apparently solid line on a surface. Some such instruments have included two rotating projected beams to produce intersecting lines at right angles to each other. See, for example, U.S. Pat. Nos. 5,218,770 and 6,202,312 in which such devices are shown as prior art. See also U.S. Pat. No. 6,065,217.
It has also been known to form lines on a surface by placing a cylindrical lens in the path of a collimated laser beam, thus spreading a narrow beam of light into a planar fan of light that forms a line on a surface. Again, see U.S. Pat. No. 6,202,312 showing such instruments, and the disclosure of that patent is incorporated herein by reference, particularly as to discussion of prior art.
There have been laser tools that produce two lines with a visible intersection, such as described in U.S. Pat. No. 5,539,990, but with an important difference from the device of this invention. The prior tools produced the intersecting lines on a surface that is generally perpendicular to the surface on which the instrument rests.
Other laser reference tools have produced spots of light on a surface, rather than solid lines of light. For example, see U.S. Pat. No. 6,005,719.
See also copending application Ser. No. 09/684,696, now U.S. Pat. No. 6,502,319, owned by the assignee of this invention, showing generation of lines on a surface on which the instrument is placed.
It is among the objects of this invention to produce an efficient portable laser reference tool that generates at least two intersecting lines of laser light on a floor or other surface against which the tool is placed, with the intersection being displaced from the instrument and visible. An accompanying object is to generate such light beams and lines without the use of moving parts, such as spinning lasers or mirrors.
SUMMARY OF THE INVENTION
A portable construction layout tool generates laser beams in two directions related by a specific angle, such as 90°. The instrument emits two fans of light in such a way as to project a pair of lines on a floor, wall or other surface on which the tool is mounted, with the intersection of the two fans being visible rather than being a “virtual” intersection inside or below the instrument, thus enabling easier setup. Compared to rotating-beam instruments, the disclosed device is simpler by avoiding moving parts, and provides for better visibility. In a preferred embodiment the non-collimated beam from a laser diode is used, and is passed through a cylinder lens to converge the beam on the narrower axis to generate the desired fan of light to be projected as a line.
In one embodiment two different laser diodes and lenses are used to generate the two fans of light, and in another embodiment a single laser diode is employed, with optics to produce the two fans of light.
It is thus a primary object of the invention to provide a rugged and reliable laser instrument, without moving parts, to produce at least two lines of light on the floor or other surface on which the instrument is mounted or placed, with the intersection of the two lines visible to the user. These and other objects, advantages and features of the invention will be apparent from the following description of a preferred embodiment, considered along with the accompanying drawings.
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Freiburger Thomas M.
Fulton Christopher W.
Trimble Navigation LLC
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