WO2005079382A2

WO2005079382A2 - Improved laser leveler

Info

Publication number: WO2005079382A2
Application number: PCT/US2005/004664
Authority: WO
Inventors: Alfred A. Pease; Timothy Ewald
Original assignee: Perceptron, Inc.
Priority date: 2004-02-12
Filing date: 2005-02-11
Publication date: 2005-09-01
Also published as: WO2005079382A3

Abstract

A laser leveler includes a first member and a second member moveably attached to the first member and adapted to settle into a predetermined orientation with respect to a gravity vector. A transmissive optical component (34) is non-moveably attached to the second member (36) and operable to form an impinging laser beam into a substantially two-dimensional plane of a laser plane. A Source of laser light (32) is non-moveably attached to the second member (36) and non-moveably disposed to ensure an emitted laser beam impinges said optical component.

Description

IMPROVED LASER LEVELER

FIELD OF THE INVENTION [0001] The present invention generally relates to laser levelers, and particularly relates to laser levelers adapted to generate a plane of laser light at a predetermined orientation with respect to the gravity vector.

BACKGROUND OF THE INVENTION [0002] Laser levelers are employed in a construction environment to perform square, plumb, and level functions. In the construction environment, the plane of laser light generated orthogonally to the gravity vector is perhaps of greatest utility. Rotating lasers have typically been employed to obtain the aforementioned laser plane. The reliability of eye-safety of these laser levelers ^' has suffered due to the inclusion of high-speed moving parts that can fail and result in a stationary laser beam that is not eye safe and fails to generate a laser plane. Thus, there exists a need for a laser leveler that can produce a laser plane without requiring a rotating laser. [0003] One attempted solution to the aforementioned problems is taught in U.S. Patent No. 6,5342,304 to Tackling et al., entitled LASER BEAM DEVICE WITH APERTURED REFLECTIVE ELEMENT. This attempted solution teaches directing a laser beam onto a mirrored right cone with the beam spot centered over the apex of the cone to produce a sheet of laser light. However, this attempted solution present three significant difficulties: difficulty of manufacture to the requisite tolerances; high laser power requirements; and loss of function during use due to lack of temperature compensation. In other words, an expensive, high power laser must be employed in accordance with the teachings of Tackling et al. to extend a perceptible laser plane to any appreciable distance, and this laser heats the reflective material during use. Since the reflective material cannot be made temperature compensating, the mirrored right cone surface material is heated unevenly by the laser during use and warps as a result. This warping, in turn, destroys the integrity of the laser plane and renders the laser leveler unsuitable for its intended purpose. Further, the high power laser is not eye safe in the event that the reflective element is destroyed. [0004] The need remains for a laser lever that is capable of reliably producing a laser plane orthogonal to the gravity vector without the requirement of motorized parts that rotate the laser in the plane. The need further remains for a laser leveler that reliably produces a laser plane orthogonal to the gravity vector that is eye safe even in the event of device component failure. The present invention fulfills these needs. SUMMARY OF THE INVENTION [0005] A laser leveler includes a first member and a second member moveably attached to the first member and operable to settle into a predetermined orientation with respect to a gravity vector. A transmissive optical component is non-moveably attached to the second member and operable to form an impinging laser beam into a substantially two-dimensional plane of a laser plane. A source of laser light is non-moveably attached to the second member and non-moveably disposed to ensure an emitted laser beam impinges said optical component. [0006] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0007] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: [0008] Figure 1 is a perspective view illustrating a laser leveler employing multiple arrays of powell lenses in accordance with the present invention; [0009] Figure 2 is an exploded view illustrating a damping mechanism employed in a gimbel in accordance with the present invention; [0010] Figure 3 is a block diagram illustrating an array of laser light sources and powell lenses in accordance with the present invention; [0011] Figure 4 is a block diagram illustrating an array of laser light sources and negative cylinders in accordance with the present invention; [0012] Figure 5 is a block diagram illustrating a high power laser light source and a negative right cone formed in an acrylic polycarbonate material in accordance with the present invention; [0013] Figure 6 is a block diagram illustrating multiple, low power laser light sources and a negative right cone formed in an acrylic polycarbonate material in accordance with the present invention; [0014] Figure 7 is a block diagram illustrating four, overlapping negative right cones formed in an acrylic polycarbonate material to provide overlapping laser planes in accordance with the present invention; and [0015] Figure 8 is a block diagram illustrating eight, overlapping negative right cones formed in an acrylic polycarbonate material to provide overlapping laser planes with at least complementary fan angles in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0016] The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. [0017] By way of overview, the laser leveler according to the present invention is illustrated in Figure 1. Accordingly, an outer housing 20 envelops power sources 22, 24, 26, and 28. A user-manipulable switch 30 selective supplies power to one or more predefined combinations of laser light sources 32A-32F. Transmissive optical elements 34A-34F form impinging laser beams from laser light sources 32A-32F into substantially two-dimensional planes of one or more laser planes. Elements 34A-34F correspond in one embodiment to powell lenses, which spread an impinging laser beam into a line of constant intensity with a fan angle of approximately one-hundred twenty degrees. Sources 32A-32F and elements 34A-34F are arrayed to cumulatively form the planes, and the resulting arrays are aligned to form multiple, perpendicular planes. The multiple arrays are non-moveably attached to a leveling component provided in part by pendulum member 36. In turn, pendulum member 36 is moveably attached to housing 20 by fastening mechanism 38. Fastening mechanism preferably corresponds to a two-axis gimbel. However, it is envisioned that other types of fastening mechanisms may be employed in accordance with the present invention. Ballast 40A and 40B ensures that the center of gravity of pendulum member 36 remains below fastening mechanism 38 regardless of orientation of housing 20. Ballast 40A and 40B correspond in one embodiment to free-floating, weighted sleeves formed about pendulum member 36 and disposed on either sides of fastening mechanism 38. However, it is envisioned that other types of ballast may be employed in accordance with the present invention. [0018] Figure 2 illustrates a motion damping mechanism adapted to hasten settling of the pendulum member 36 into a predetermined orientation with respect to the gravity vector. Lentz's law assures that a conductor in relative motion with respect to a magnetic field will generate an electromotive force opposing the magnetic field. Accordingly, magnetic field sources 42A-42D and non-ferromagnetic conductors 44A-44D are disposed in sufficient proximity to one another to ensure that movement of the pendulum member 36 with respect to the housing produces in one or more conductors an electromotive force opposing change in position of one or more of the magnetic field sources with respect to position of the conductor. Preferably, copper conductors are formed in gimbel axels 46A-46D of the gimbel, and permanent magnets are disposed in gimbel axel slots 48A-48D. It should be readily understood, however, that the conductors may alternatively be formed in the gimbel axel slots 48A-48D, and the magnets may be disposed in gimbel axels 46A-46D of the gimbel. Either of these arrangements assures that a gimbel axle rotating within a gimbel slot will experience the aforementioned electromotive force, and that the pendulum member will therefore settle along the effected axis at a constant rate rather than at an exponential rate. This electromotive force, therefore, counteracts the tendency of a pendulum effected by gravitational acceleration to repeatedly swing back and forth over a point of equilibrium. As a result, settling of the pendulum member is significantly hastened. [0019] Figure 3 illustrates an array of three approximately fifteen mille Watt laser light sources 32A-32C and three powell lens optical elements 34A- 34C complementarily disposed to provide a three-hundred sixty degree plane of laser light. Each plane 50A-50C of the plane has a substantially constant intensity due to the relatively unique beam spreading characteristics of powell lenses. Each plane 50A-50C also has a substantially one-hundred and twenty degree fan angle, three of which complementarily provide a three-hundred sixty degree plane by at least abutting one another without overlap. Only two complementarily arrayed modules of light sources and powell lenses are required to provide a plane of at least one-hundred eighty degrees. [0020] The light sources 32A-32C required to drive the powell lenses, however, need to be of sufficient power that eye safety becomes an issue. Therefore, optical detectors 52A-52C, such as photodiodes, are disposed to detect laser light reflected from optical elements 34A-34C. Principles of back- reflection are exploited for this purpose. As a result, if one of optical elements 34A-34C is removed, then one of optical detectors 52A-52C ceases to detect light reflected from the removed element despite the fact that power has recently been supplied to the corresponding laser light source. In response, the corresponding switching mechanism in line with the corresponding power source prevents power from flowing to the corresponding laser light source. [0021] Figure 4 illustrates an array of eight laser light sources 32A-32H in the form of laser diode modules having laser diodes and collimating lenses with a five mille Watt power supply. These relatively low power laser diode modules are commercially available and significantly less expensive than relatively high power laser diodes, which are not as readily available in modular form. This array includes eight optical elements 34A-34H in the form of negative cylinders formed in a transmissive material, such as acrylic polycarbonate. The negative cylinders are capable of providing laser planes 50A-50H of varying intensity with fan angles of forty-five degrees. Negative cylinders are generally commercially available that nearly provide the aforementioned fan angle, and nine or more sources and elements of this type may be employed to provide a three-hundred sixty degree plane. However, it is envisioned that negative cylinders may be produced to order that more fully provide the aforementioned fan angle, thereby reducing the number of modules to eight. It is further envisioned that less than eight modules may be employed to provide a laser plane with a fan angle of less than three-hundred sixty degrees, such as a one- hundred eighty degree plane. [0022] The intensity of a laser plane produced with a negative cylinder varies because the laser spot is more intense in the center of the spot than at the edges of the spot. However, it should be readily understood in the housing of varying intensity laser planes that the edges of the fan angle denote the point at which the intensity has decreased to half. Thus, the perceptible planes overlap substantially to minimize perceptible variations in intensity. This array of eight, relatively low power modules thus provides an inexpensive and eye safe solution. It is also notable that ease of replacement of such a module is an additional advantage of this modular array. [0023] Figure 5 illustrates an optical element 34 in the form of a negative right cone formed in a transmissive material, such as acrylic polycarbonate. This embodiment exploits principles of internal reflection to form a three-hundred sixty degree plane of laser light from an impinging laser beam. Distributing the laser spot about the vertex results in a plane of uniform intensity. This embodiment, however, requires a relatively high power laser light source 32 on the order of fifty mille Watts. As a result, eye safety is an issue that must be resolved by provision of optical detector 52, which exploits principles of internal reflection, and switching mechanism 30 to cut power from source 22 as described above with reference to Figure 3. [0024] Figure 6 illustrates that multiple laser light sources 32A and 32B of lower power may be employed to reduce expense and increase eye safety. In this embodiment, however, the laser spots impinging the inner-material surface of the negative right cone are not distributed about the vertex of the cone. As a result, the plane may be perceptibly incomplete to the eye, and it may be necessary to overlap multiple, negative right cones as illustrated in Figures 7 and 8 to increase overlap and widen the fan angle of formed laser planes. The negative right cones may also be moved further apart, even to the point that they do not overlap, so that eye safety can be effectively maintained and heating of element material can be minimized. Nevertheless, the laser spots are not centered over the vertices in this array of negative right cones, which may or may not overlap, but are disposed to produce a laser plane as described above. [0025] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.

Claims

CLAIMS What is claimed is:

1. A laser leveler comprising: a first member; a second member moveably attached to said first member and adapted to settle into a predetermined orientation with respect to a gravity vector; a transmissive optical component non-moveably attached to said second member and operable to form an impinging laser beam into a substantially two-dimensional plane having a positive fan angle; and a source of laser light non-moveably attached to said second member and non-moveably disposed to ensure an emitted laser beam impinges said optical component.

2. The leveler of claim 1 , wherein said optical component corresponds to a negative cylinder formed in a transmissive material.

3. The leveler of claim 2, wherein said transmissive material is an acrylic polycarbonate material.

4. The leveler of claim 1 , wherein said optical component corresponds to a negative right cone formed in a transmissive material.

5. The leveler of claim 4, wherein said transmissive material is an acrylic polycarbonate material.

6. The leveler of claim 1 , wherein said optical component corresponds to a powell lens.

7. The leveler of claim 1 , comprising a fastening mechanism moveably attaching said second member to said first member.

8. The leveler of claim 7, comprising a ballast moveably attached to said second member and operable to ensure that a center of gravity of the second member remains below said fastening mechanism.

9. The leveler of claim 7, wherein said fastening mechanism corresponds to a two-axis gimbel.

10. The leveler of claim 9, comprising a motion damping mechanism adapted to hasten settling of said second member into the predetermined orientation with respect to the gravity vector, wherein said damping mechanism includes a magnetic field source and a non-ferromagnetic conductor disposed in sufficient proximity to one another to ensure that movement of said second member with respect to said first member is likely to produce in the conductor an electromotive force opposing change in position of the magnetic field source with respect to position of the conductor.

11. The leveler of claim 10, wherein at least one of: said non-ferromagnetic conductor is formed in a gimbel axel of said gimbel, and said magnetic field source is formed in a gimbel axel slot; and said non-ferromagnetic conductor is formed in a gimbel axel slot, and said magnetic field source is formed in a gimbel axel of said gimbel.

12. The leveler of claim 1 , comprising an optical detector disposed in sufficient proximity to said optical component to detect laser light reflected from said optical component.

13. The leveler of claim 12, comprising a switching mechanism adapted to cut power to said source of laser light if said optical detector fails to detect laser light reflected from said optical component.

14. The leveler of claim 1 , comprising a first plurality of said sources of laser light and said optical components arrayed to form an at least one-hundred eighty degree plane of laser light orthogonal to the gravity vector when said second member settles into the pre-determined position with respect to the gravity vector.

15. The leveler of claim 14, comprising a second plurality of said sources of laser light and said optical components arrayed to form a second at least one-hundred eighty degree plane of laser light perpendicular to the first at least one-hundred eighty degree plane of laser light when said second member settles into the pre-determined position with respect to the gravity vector.

16. The leveler of claim 15, comprising a third plurality of said sources of laser light and said optical components arrayed to form a third at least one- hundred eighty degree plane of laser light perpendicular to the first on-hundred- eighty degree plane of laser light and the second at least one-hundred eighty degree plane of laser light when said second member settles into the predetermined position with respect to the gravity vector.

17. The leveler of claim 16, comprising a user-manipulable switching mechanism adapted to selectively supply power to said first plurality, said second plurality, and said third plurality of said sources of laser light.

18. The leveler of claim 1 , wherein said source of laser light corresponds to a laser diode of power not greater than ten mille-Watts.

19. The leveler of claim 1 , wherein said source of laser light corresponds to a laser diode of power not greater than five mille-Watts.

20. The leveler of claim 1 , wherein said source of laser light corresponds to a laser diode module having a collimating lens and a substantially five mille-Watt power supply.

21. A laser leveler comprising: a leveling component; and an array of laser-plane-producing modules provided to said leveling component, at least two of said laser-plane-producing modules having a laser diode module and an optical element forming a laser beam produced by the laser diode module into a laser plane having a fan angle less than one-hundred eighty degrees.

22. The laser leveler of claim 21 , wherein a first laser plane having a fan angle less than one-hundred eighty degrees is arrayed to at least abut within a common plane a second laser plane having a fan angle less than one-hundred eighty degrees.

23. The laser leveler of claim 22, wherein the first plane is arrayed to overlap the second plane.

24. The laser leveler of claim 21 , wherein said array produces a laser plane having a fan angle of at least one-hundred eighty degrees.

25. The laser leveler of claim 21 , wherein the laser diode module has a collimating lens and a power supply.

26. The laser diode module of claim 25, wherein the power supply is adapted to supply not greater than five mille-Watts of power.

27. The laser diode module of claim 21 , wherein said leveling component includes: a housing; a fastening mechanism; and a pendulum member moveably attached by said fastening mechanism to said housing, said pendulum member adapted to settle into a predetermined orientation with respect to a gravity vector.

28. The laser diode module of claim 27, wherein said mechanism corresponds to a two-axis gimbel, the leveler further comprising: a damping mechanism integrated into moving parts that respetively provide both axes of the gimbel; and a ballast provided to said pendulum member and adapted to ensure that a center of gravity of the pendulum member remains below the gimbel.

29. The laser leveler of claim 21 , wherein the optical component corresponds to a negative cylinder.

30. The laser leveler of claim 21 , wherein the optical component corresponds to a powell lens.