Automatic plumb and level tool

• US 5,075,977 A
• Filed: 10/22/1990
• Issued: 12/31/1991
• Est. Priority Date: 10/22/1990
• Status: Expired due to Term

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Spectra-Physics Incorporated (MKS Instruments Incorporated)
• Inventors: Rando, Joseph F.
• Primary Examiner(s): HAROIAN, HARRY
• Application Number:
  US07/602,353
• Time in Patent Office: 435 Days
• Field of Search: 33/227, 33/228, 33/DIG. 21, 33/290, 33/291, 356/138, 356/146, 356/250, 356/147, 356/148, 356/149
• US Class Current: 33/227
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01B 3/00 Measuring instruments characterised by the use of mechanical techniques
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: Y10S 33/21 with laser

Abstract

An automatic plumb, level and pointing tool uses a visible laser diode to project a beam in any of three different modes through a beam exit window. The tool, approximately the size and shape of a tape measure, can be placed on one edge to project a tilt-compensated vertical beam. Placed on another edge 90°-rotated, the tool projects through the same exit window a tilt-compensated horizontal beam. When laid on either of its larger flat sides, the tilt compensation becomes inoperative and the tool projects a beam which is fixed relative to the housing. In a preferred embodiment, separate pendulous or cantilevered mirrors are used for vertical and horizontal tilt correction and are selected by the influence of gravity as the tool is laid on one edge or the other. In further described embodiments, two separate laser diodes may be used, or the laser tool may be intergrated with other tools such as a tape measure or a squaring tool. A preferred cantilever beam tilt compensator achieves a wide range of accurate compensation through substantial tilt of the device in the horizontal mode.

Claims

1. A portable laser beam projecting device for indicating level, plumb and alignment, comprising,

a hand carryable housing having at least two sides capable of resting stably on a flat surface, the two sides being substantially perpendicular to each other,

laser source means mounted within the housing, for producing at least one collimated beam of visible laser light,

a laser beam exit window in the housing,

beam directing means in the housing for directing a beam from the laser source means vertically out of the housing through the exit window when a first side of said two sides is held generally horizontal, and for directing a beam from the laser source means horizontally out of the housing through the exit window when a second side of said two sides is held generally horizontal, and

tilt compensation means in the housing and associated with the beam directing means for correcting for relatively small tilt angles of the housing as it rests with one of said two sides against surfaces not truly horizontal or not truly vertical, and for projecting the beam through the exit window in substantially true vertical orientation or substantially true horizontal orientation despite such relatively small tilt angles.

2. The device of claim 1, wherein the housing includes a third side capable of resting stably on a flat surface, and further including beam fixing means associated with said tilt compensation means, for rendering the tilt compensation means inactive and holding the path of a laser beam from the laser source means steady and fixed relative to the housing as it exits the housing through the exit window when the housing is positioned with said third side generally horizontal, so that the device may be used as a pointer and alignment tool with said third side generally horizontal.

3. The device of claim 1, wherein said laser source means comprises a pair of laser diodes, one for projecting the vertical beam and one for projecting the horizontal beam, and including means for switching to activate one laser diode and de-activate the other, when the tool is changed in position from said first side to said second side being generally horizontal.

4. A laser beam projecting device for plumbing, leveling and alignment, comprising,

a hand-carryable housing having at least two sides capable of resting stably on a flat surface, the two sides being substantially perpendicular to each other, and including two broad sides, with the housing being generally the size and shape of a pocket tape measure,

laser source means mounted within the housing, for producing at least one collimated beam of visible laser light,

a laser beam exit window in the housing, positioned in neither of two said sides nor on said broad sides,

beam directing means in the housing for directing a beam from the laser source means vertically out of the housing through the exit window when a first side of said two sides is held generally horizontal, and for directing a beam from the laser source means horizontally out of the housing through the exit window when a second side of said two sides is held generally horizontal, and

tilt compensation means in the housing and associated with the beam directing means for correcting for relatively small tilt angles of the housing as it rests with one of said two sides against surfaces not truly horizontal or not truly vertical, and for projecting the beam through the exit window in substantially true vertical orientation or substantially true horizontal orientation despite such relatively small tilt angles.

5. The device of claim 4, further including a tape measure rotatably mounted side by side and against one of the broad sides of the laser beam projecting device such that the laser beam may be projected in a direction parallel to a tape of the tape measure, or perpendicular to the tape

6. The device of claim 4, wherein the housing has dimensions no greater than about four inches in height, about four inches in length and about two inches in thickness.

7. The device of claim 4, wherein the housing has dimensions no greater than about 33/4 inches in height and in length, and no greater than about 11/4 inches in thickness.

8. A portable laser beam projecting device for indicating level, plumb and alignment, comprising,

a hand carryable housing having dimensions no greater than about four inches in height, about four inches in length and about two inches in thickness, and having at least two sides capable of resting stably on a flat surface, the two sides being substantially perpendicular to each other,

laser source means mounted within the housing, for producing a collimated beam of visible laser light,

a laser beam exit window in the housing,

beam directing means in the housing for directing the beam from the laser source vertically out of the housing through the exit window when a first side of said two sides is held generally horizontal, and for directing the beam from the laser source horizontally out of the housing through the exit window when a second side of said two sides is held generally horizontal, and

tilt compensation means in the housing and associated with the beam directing means for correcting for relatively small tilt angles of the housing as it rests with one of said two sides against surfaces not truly horizontal or not truly vertical, and for projecting the beam through the exit window in substantially true vertical orientation or substantially true horizontal orientation despite such relatively small tilt angles.

9. The device of claim 8, wherein the tilt compensation means comprises weighted pendulum flexure means mounted in the housing and having an attached first mirror, positioned in the path of the laser beam for reflecting the beam to substantially true vertical orientation toward the exit window when the housing rests with the first side horizontal, and weighted cantilever flexure means mounted in the housing and having an attached second mirror, positioned to intercept the laser beam when the housing rests with the second side generally horizontal, and for reflecting the beam to substantially true horizontal orientation toward the exit window.

10. The device of claim 9, further including a closed liquid damping bath in the housing, within which the weighted pendulum flexure means and the weighted cantilever flexure means are positioned, with a transparent sealing interface containing the liquid and interposed between the mirrors and the exit window.

11. The device of claim 9, further including a closed liquid damping bath in the housing, within which the weighted pendulum flexure means and the weighted cantilever flexure means are positioned, with a transparent sealing interface containing the liquid and interposed between the mirrors and the exit window, and with each of the weighted pendulum flexure means and the weighted cantilever flexure means being effective when in use to flex under gravity to partially correct the orientation of the beam as it is reflected off the first or second mirror, with the remainder of the compensation accomplished by the emergence of the beam from the liquid damping bath to air, whereby the compensation is multiplied in accordance with the index of refraction of the liquid damping bath.

12. The device of claim 9, further including air damping means in the housing for damping the movement of the weighted pendulum flexure means and of the weighted cantilever means during flexure by air resistance when the position of the tool housing is changed.

13. The device of claim 9, further including magnetic damping means in the housing for damping the movement of the weighted pendulum flexure means and of the weighted cantilever flexure means during flexure by a magnetic field when the position of the tool housing is changed.

14. The device of claim 9, wherein the weighted cantilever flexure means is positioned to flex and hang by its weight out of the path of the laser beam when said first side of the housing is generally horizontal, and to move onto the path of the laser beam, interposing between the laser source means and the first mirror, by weight-induced flexure when the housing is shifted to a position wherein said second side of the housing is generally horizontal.

15. The device of claim 9, wherein the weighted cantilever flexure means comprises a cantilever beam with varied cross section throughout its length, varied so as to enhance the self-leveling range of the cantilever beam, increasing the range of tilt of the tool through which the weighted cantilever flexure means will compensate to keep the beam substantially horizontal.

16. The device of claim 15, wherein the cantilever beam is bifurcated and has a pair of spaced legs, each of varied cross section and each uniformly tapering to narrow dimension toward the end with the second mirror, and further including cantilever brake means fixed relative to the housing and closely positioned between the two tapered legs of the cantilever beam, such that when the device is turned to a position wherein neither the weighted pendulum flexure means nor the weighted cantilever flexure means is active, the cantilever beam will bend slightly due to gravity and one of the tapered legs will engage against the brake means, immobilizing the weighted cantilever flexure means in a position such that the laser beam will reflect from the second mirror without compensation, whereby the device can be laid on a third side or held with the third side horizontal with said second mirror immobilized and reflecting the beam generally horizontally through the exit window, so that the device may be used as a pointer and alignment tool with said third side generally horizontal.

17. The device of claim 8, wherein the tilt compensation means comprises gravity responsive means for selectively positioning a first tilt compensated mirror in the path of the laser beam when said first surface of the housing is generally horizontal, or a second tilt compensated mirror in the path of the laser beam when said second side of the housing is generally horizontal.

18. The device of claim 17, wherein the housing includes a third side capable of resting stably on a flat surface, and further including beam fixing means associated with the tilt compensation means, for rendering the tilt compensation means inactive and holding the path of the laser beam steady and fixed relative to the housing as it exits the housing through the exit window when the housing is positioned with said third side generally horizontal, so that the device may be used as a pointer and alignment tool with said third side generally horizontal.

19. The device of claim 18, wherein the beam fixing means comprises gravity activated means for restricting the freedom of movement of the second tilt compensated mirror when the tool housing is moved to a position wherein said third side is generally horizontal.

20. The device of claim 8, wherein the housing has dimensions no greater than about 33/4 inches in height and in length, and no greater than about 11/4 inches in thickness.

21. A laser operated tool for projecting a plumb line, a level line or an alignment line, comprising,

a housing having at least two flat edge surface means, at right angles to each other, for being placed stably on a generally horizontal surface,

laser diode means mounted within the housing, for emitting a visible laser beam,

battery means contained within the housing, for powering the laser diode means,

an exit window opening in the housing, positioned in the path of the laser beam so as to permit the laser beam to be projected out of the housing,

first reflector means for receiving a laser beam from the laser diode and redirecting the laser beam vertically out of the housing through the window opening, when the housing rests on a first of said flat edge surface means, said first reflector means including first tilt compensation means for correcting for small tilt angles of the housing when positioned with the first flat edge surface means not truly horizontal and for assuring that the laser beam is oriented substantially truly vertically in spite of such small tilt angles,

second reflector means mounted in the housing and positioned to receive the beam from the laser and to redirect the laser beam horizontally out of housing through the window opening, when the housing rests on a second of said flat edge surface means, said second reflector means including second tilt compensation means for correcting for small tilt angles of the housing when positioned with the second flat edge surface means not truly horizontal and for assuring that the laser beam is oriented substantially truly horizontally in spite of such small tilt angles, and

means associated with the first and second reflector means for permitting the laser beam to be reflected from the first reflector means without interference from the second reflector means, when the housing rests on said first flat edge surface means, and for permitting the laser beam to be reflected from the second reflector means without interference from the first reflector means, when the housing rests on said second flat edge surface means.

22. A tool according to claim 21, wherein the first reflector means comprises a first mirror mounted on a pendulum weight, and wherein the first tilt compensation means comprises a generally vertical, flexible pendulum shaft fixedly mounted in the housing at its upper end and connected to the pendulum weight at its lower end, positioned so as to adjust the angular orientation of the first mirror by flexing of the pendulum shaft due to gravity when the housing of the tool is positioned with the first flat edge surface means non-horizontal.

23. A tool according to claim 22, wherein the second reflector means comprises a second mirror mounted on a cantilever weight obliquely with respect to the laser beam, and wherein said second tilt compensation means comprises a cantilever beam means having one end fixedly mounted in the housing and an opposite end fixed to the cantilever weight, for flexing by gravity when the housing is positioned with the second flat edge surface means generally horizontal and for flexing to adjust the angular orientation of the obliquely mounted second mirror to compensate for tilt of the second flat edge surface means from horizontal.

24. A tool according to claim 23, wherein the cantilever beam means comprises a cantilever beam with varied cross section throughout its length, varied so as to enhance the self-leveling range of the cantilever beam, increasing the range of tilt through which the second tilt compensation means will compensate to keep the beam substantially horizontal.

25. A tool according to claim 23, further including damping means for damping the movement of the first and second tilt compensation means during flexure, when the position of the housing is changed.

26. A tool according to claim 25, wherein the damping means comprises a bath of substantially transparent damping liquid within which the first and second mirrors and the first and second tilt compensation means are immersed, with sealed containment means inside the housing for containing the damping liquid, including a transparent window in the containment means for passage of the reflected laser beam outwardly through the window opening of the housing.

27. A tool according to claim 23, wherein the damping means comprises a bath of substant transparent damping liquid within which the first and second mirrors and the first and second tilt compensation means are immersed, with sealed containment means inside the housing for containing the damping liquid, including a transparent window in the containment means for passage of the reflected laser beam outwardly through the window opening of the housing.

28. A tool according to claim 23, wherein the means for permitting the laser beam to be reflected without interference of the first and second reflector means comprises said cantilever beam being oriented obliquely in the housing such that, with the housing in a first position with the first flat edged surface generally horizontal, the second mirror is out of and below the path of the laser beam as projected from the laser diode means, due to the cantilever weight flexing the cantilever beam downwardly, and, with the housing in a position with the second flat edged surface generally horizontal and the first flat edged surface generally vertical, the cantilever beam flexes downwardly in an opposite direction by the weight of the cantilever weight, moving the second mirror into the path of the laser beam projected from the laser diode means.

29. A tool according to claim 21, wherein the means for permitting the laser beam to be reflected without interference of the first and second reflector means comprises gravity-responsive means forming a part of said tilt compensation means, for positioning the first reflector means in the path of the laser beam when the housing rests on the first flat edge surface means while moving the second reflector means out of the path of the laser beam, and said gravity-responsive means including means for moving the second reflector means onto the path of the laser beam when the housing rests on the second flat edge surface means.

30. A tool according to claim 21, wherein the housing has a third flat edge surface means, generally at right angles to the first and second flat edge surface means, and further including pointing beam means associated with the tilt compensation means, for deactivating the tilt compensation means when the tool is positioned with the third flat edge surface means generally horizontal, and for projecting the beam out of the housing through the exit window with the beam in fixed orientation relative to the housing, whereby the tool may be laid on a horizontal surface to project an aiming or pointing beam which will remain in a stable position.

31. A tool according to claim 30, wherein the pointing beam means includes means connected to one of the first and second reflector means, for fixing in position said one relfector means in position with respect to the housing and for holding the other of said first and second reflector means out of the path of the laser beam when the tool is held with the third side generally horizontal.

32. A tool according to claim 21, further including air damping means for damping the movement of the first and second tilt compensation means during the flexure using air resistance within the housing, when the position of the housing has changed.

33. A tool according to claim 21, further including magnetic damping means for damping the movement of the first and second tilt compensation means during flexure using a magnetic field, when the position of the housing has changed.

34. A tool according to claim 22, wherein the generally vertical, flexible pendulum shaft comprises a two-axis pendulum shaft having gravity responsive means for effecting a first degree of compensation generally within a plane including the beam incident and reflected from the first mirror and for effecting a second, different degree of compensation in a generally transverse plane, whereby the tool is accurate in compensating for tilt in either plane.

35. A tool according to claim 22, further including means for caging the pendulum weight and at least partially immobilizing it when the tool is not held with the first flat edge surface means generally horizontal, to prevent excessive movement of the pendulum weight when not in use.

36. A portable laser beam projecting device for indicating plumb, comprising,

a hand carryable housing having two vertical sides and two horizontal sides,

first laser source means mounted within the housing, for producing a first collimated laser beam of visible laser light,

a first laser beam exit window in an upper of said two horizontal sides,

first reflector means for receiving the first laser beam from the first laser source means and redirecting the laser beam vertically out of the housing through the first laser beam exit window, with first tilt compensation means associated with the first reflector means for correcting for small tilt angles of the housing when positioned with the vertical sides not truly vertical, and for assuring that the laser beam is oriented substantially truly vertical in spite of such small tilt angles,

second laser source means mounted within the housing, for producing a second collimated laser beam of visible laser light,

a second laser beam exit window in the housing, in a lower of the two horizontal sides and positioned substantially directly below the first laser beam exit window, and

second reflector means for receiving the second laser beam from the second laser source means and redirecting the second laser beam vertically downwardly out of the housing through the second laser beam exit window, with second tilt compensation means associated with the second reflector means for correcting for small tilt angles of the housing when positioned with the vertical sides not truly vertical and for assuring that the second laser beam is oriented substantially truly vertical in spite of such small tilt angles,

whereby the laser beam projecting device can simultaneously project substantially truly vertical and aligned laser beams upwardly and downwardly out of the housing.

37. The laser beam projecting device of claim 36, wherein the first and second tilt compensation means comprise a pendulum weight in the housing, a generally vertical, flexible pendulum shaft secured to the pendulum weight and fixedly mounted in the housing at its upper end, a first beam reflecting mirror mounted obliquely on the upper side of the pendulum weight, in the path of the laser beam from the first laser source means, and a second mirror mounted obliquely on the lower side of the pendulum weight, in the path of the second laser beam from the second laser source means, whereby a single weighted pendulum device serves simultaneously to correct for tilt compensation of the housing with respect to both laser beams.