AU733064B2 - A vertical alignment device - Google Patents

Description

-1- Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

(ORIGINAL)

Name of Applicant: Actual Inventors: Address for Service: Invention Title: Beam Technologies of Australia Pty Ltd GINGELL Phillip DAVIES COLLISON CAVE, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000.

A vertical alignment device Details of Associated Provisional Application(s) No(s): PO6312/97 The following statement is a full description of this invention, including the best method of performing it known to us: Q:\OPER\LKA\P06312.107 17/4/98 V P:\OPER\LKANBEAM.PRV 17/4/98 -2- A VERTICAL ALIGNMENT DEVICE FIELD OF THE INVENTION This invention relates to apparatus for establishing vertical alignment. It has particular although not exclusive application to the building construction industry.

oooo.i :°ooto BACKGROUND ART In the building construction industry it is very often necessary to vertically align reference 10 points during construction of a building or other structure. For example, in the construction of high rise buildings a reference grid is usually established on each floor of the building.

The position of components such as partitions, lighting systems, and other services is specified with reference to this grid. Accordingly, it is frequently necessary to transfer a reference point from the floor to the adjacent ceiling in order to properly position the building o 15 components.

In the past these reference points have been transferred using a conventional string plumbob.

Whilst this is a relatively simple device for the purpose, it frequently involves the use of two people. Additionally, stabilisation of the plumbob can be relatively time consuming. A further disadvantage is that the plumbob is not accurate over substantial distances particularly in open buildings where wind gusts can affect the position of the plumbob.

Current alternatives to the traditional plumbob are either expensive or do not offer a sufficiently improved accuracy. One such class of devices is the self levelling or planing laser. This is a very expensive and sophisticated device primarily intended to provide extremely accurate horizontal planes of reference. Whilst these types of devices can be configured for use in a vertical mode they are not adapted for alignment with a floor marking to establish a corresponding vertically aligned position on a ceiling, for example. Planing lasers are also expensive fragile pieces of equipment.

V p:\OPER\LKA\BEAM.PRV 17/4/98 -3- Another current device is known as a "Plumbat" and is essentially a small free swinging laser.

It usually relies upon a string line for suspension and thus has the same problems as a suspended weight plumbob.

Yet another device known as the laser plumb is described in Australian Patent Application No 45569/96. This device is a small laser which is either suspended on a cord or mounted on a levelling base. The base is manually adjustable by reference to a bubble level to align the laser either vertically or horizontally. When suspended by the cord the device has the same problems as a conventional plumb bob. The manually adjustable arrangement suffers from 10 the disadvantages of being time consuming to operate and being of limited accuracy.

Other currently available devices rely on mirrors to reflect laser light in any one of three directions. These devices do not have sufficient accuracy for use in the building industry.

Also, additional marking out is required in order to translate a point vertically upwards and the metal springs and fluid damping used in the system are prone to temperature and age induced errors.

DISCLOSURE OF THE INVENTION It is an object of this invention to provide a vertical alignment device which will overcome, or at least ameliorate one or more of the foregoing disadvantages.

Accordingly, this invention provides a vertical alignment device including light emitting means to produce a source beam of substantially coherent visible light, two mutually perpendicular reflective surfaces each arranged in part of the path of said beam to direct output beams of said visible light coaxially in opposite directions; and directing means to support said light emitting means and reflective surfaces under the influence of gravity so that the axis of said output beams is vertical.

Preferably, the reflective surfaces are two adjacent surfaces of a triangular prism. In the preferred form of the invention the prism has highly polished metal surfaces.

P:\OPERUXjA\BEAM.PRV 171/4/98 -4- The prism is preferably provided with manual adjustors for calibration purposes.

The light emitting means preferably includes a laser and more preferably a light emitting laser diode.

Preferably, the directing means is a gimball mechanism to which, in one form of the invention, the laser and prism are mounted. The laser is preferably mounted to provide a horizontal beam with respect to the vertical axis of the gimball.

°o *o One embodiment of the invention will now be described, by way of example only.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawing which is a schematic elevation of a vertical alignment device oaccording to this invention.

BEST MODE FOR CARRYING OUT THE INVENTION Referring to the drawing the vertical alignment device 10 comprises a mounting plate 11 to which a gimball mechanism 12 is mounted by means of a bracket 13. The gimball mechanism 12 is of substantially known arrangement and has bearings on mutually perpendicular axes 14 and 15 to provide two degrees of freedom of movement. A plastics housing block 16 is mounted with the gimball 12 by screws 17. A generally tubular light emitting laser diode 18 is mounted horizontally in a bore in the housing and perpendicular to the depending direction of gimball 12. A triangular prism 19 is mounted on an axle 20 within a recess (not shown), in the housing 16. The prism 19 has two reflective surfaces 21, 22 that are mutually perpendicular.

The axle 20 is able to move in slotted apertures (not shown) in the housing in response to movement of adjusting screws 23 and 24 extending through the plastics housing 16. Although only two screws 23, 24 are shown there are four such screws with an opposed set 23, 24 at each end of axle 20. This allows the axle 20 to be moved up and down as viewed in the 'I P:\OPER\LKA\BEAM.PRV 17/4/98 drawing and twisted within that plane in accordance with the adjustment of the screws. Two further screws 25, 26 extend through the housing 16 and bear against the rear surface of prism 19. This allows movement of prism 19 in a rotational plane about axle The beam emitted by a laser diode 18 is elongate and has dimensions of approximately 4mm by 2mm. The beam is arranged such that its longer dimension is arranged vertically as viewed in the drawing so that part of the beam impinges upon both of surfaces 21 and 22 of the prism 19. Because the surfaces are mutually perpendicular the two beams are reflected coaxially in opposite directions.

The various adjusting screws 23, 24, 25 and 26 provide for initial calibration adjustment of the beams in the vertical plane.

The lower end of gimball 12 includes a block 27 secured to the gimball 12 by screws 28. A frusto conical recess 29 is formed in the upper surface of block 27 and terminates in a cylindrical aperture 30. Recess 29 and aperture 30 receive a pin 31 mounted on an arm 32.

The arm 32 is connected with a shaft 33 arranged for reciprocating movement by a means of bearing blocks 34, 35 and 36. A compression spring 37 acts between bearing block 34 and a collar 38 secured to shaft 33. An extension of collar 38 is able to make contact with a switching block 39.

The upper end of shaft 33 extends through plate 11 and is fitted with a knob 40. A pin 41 also extends through shaft 33 and can be aligned with a longitudinal groove 42 in bearing block 36. A battery pack 43 is mounted with plate 11 to power the device.

As depicted in the drawing the device 10 is off with the gimball 12 locked in position by pin 31 engaging aperture 30. In use, the device is positioned approximately adjacent a reference point on a floor. Knob 40 is rotated slightly to align pin 41 with slot 42. This allows shaft 33 to move upwardly under the action of spring 37. As a consequence, the contact between collar 38 and switching block 39 is broken and power is supplied via appropriate circuitry P\OPER\LKA\61971-98.DOC 21/2101 -6- (not shown) to laser diode 18. The upward movement of shaft 33 also withdraws pin 31 from aperture 30. This allows the gimball 12 to move freely under the action of gravity. Once the gimball 12 has stabilised in position the upwardly and downwardly directed beams of light from surfaces 21 and 22 are oriented on a vertical axis. The position of the device 10 is adjusted so that the lower beam strikes the reference mark on the floor. When the lower beam is stabilised on the reference mark on the floor, the upwardly directed beam marks the corresponding point on an upper surface such as a ceiling. In order to accelerate the stabilising of the gimball 12 the knob 40 can be partially depressed so that the pin 31 enters the frusto conical recess 29. This restricts the movement of the gimball 12 to the distance between the end of the pin 31 and the corresponding surface of the frusto conical recess 29. As the pin 30 is moved further down by the depression of the knob, oscillations of the gimball 12 can be reduced. Once the oscillations of the gimball have reduced the knob 40 can be released to allow the gimball to move freely.

An indicator light (not shown) is provided to indicate when the pin 31 is touching block 27.

This indicator light thus provides a visible indication that the gimball 12 is either locked or restricted in movement and thus the beam is not vertically orientated.

The foregoing describes only one embodiment of this invention and modifications can be made, :without departing from the scope of the invention.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that the prior art forms part of the common general •knowledge in Australia.

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Claims (11)

1. A vertical alignment device including light emitting means to produce a source beam of substantially coherent visible light, two mutually perpendicular reflective surfaces each arranged in part of the path of said beam to direct output beams of said visible light coaxially in opposite directions; and directing means to support said light emitting means and reflective surfaces under the influence of gravity so that the axis of said output beams is vertical.

2. A vertical alignment device as claimed in claim 1 wherein said reflective surfaces are two adjacent surfaces of a triangular prism.

3. A vertical alignment device as claimed in claim 2 wherein said prism has highly polished metal surfaces.

4. A vertical alignment device as claimed in claim 2 or claim 3 including manually operable adjustors to change the orientation of the prism or a portion of the prism for calibration purposes.

5. A vertical alignment device as claimed in any one of claims 1 to 4 wherein said light emitting means includes a laser.

A vertical alignment device as claimed in claim 5 wherein the laser is a light emitting laser diode.

7. A vertical alignment device as claimed in any one of claims 1 to 6 wherein said directing means is a gimball mechanism.

8. A vertical alignment device as claimed in claim 7 wherein said light emitting source is arranged to provide a horizontal beam with respect to the vertical axis of the gimball. P:\OPER\LKA\61971-98.DOC 6/3/01 -8-

9. A vertical alignment device as claimed in claim 7 or claim 8 wherein including selectively operable limit means to restrict the movement of said gimball mechanism to clamp oscillations.

A vertical alignment device as claimed in claim 9 wherein said limit means includes a pin selectively extendable into a frusto conical aperture.

11. A vertical alignment device substantially as described with reference the accompanying drawing. DATED this 6th day of March, 2001 Beam Technologies of Australia by DAVIES COLLISON CAVE Patent Attorneys for the applicants *00 oo oooo *2"