WO1993022619A1

WO1993022619A1 - Vertical alignment apparatus

Info

Publication number: WO1993022619A1
Application number: PCT/AU1993/000176
Authority: WO
Inventors: Graeme Lyle Sawers; Philip David Gingell
Original assignee: Verticalign Aust Pty. Ltd.
Priority date: 1992-04-27
Filing date: 1993-04-27
Publication date: 1993-11-11

Abstract

A vertical alignment apparatus employs a gimbal mounted laser tube (30) having coaxially aligned light emitting aperture (39, 40) at opposed ends thereof. A safety switch (45) comprises a retractable member (46) actuated by a rotary knob (58) to mechanically disengage a gimbal mounted frame (32) and to electrically couple the laser tube (30) for excitation. A metallic body (42) mounted on the frame (32) and having a frusto conically shaped aperture (44) serves as a mechanical locking means and to facilitate electrical isolation of the laser tube (30) at a predetermined angle of inclination by opening a circuit which magnetically neutralises a permanent magnet (57) which maintains a closed circuit for energisation of the laser tube (30) under normal operating conditions.

Description

VERTICAL ALIGNMENT APPARATUS

This invention is concerned with improvements in levelling devices and particularly, although not exclusively, is concerned with an apparatus for establishing vertical alignment for building construction purposes and.the like.

In the building construction industry it is desirable (and in some cases essential) to be able to align vertically one reference point with another to ensure accuracy of construction.

For example, in high rise building construction, the placement of fixings for internal partitions or dividing walls is usually effected by first marking out the fixing positions on the floor and then using a plumb bob or the like to locate corresponding vertically aligned positions on the ceiling thereabove. Similarly in installation of suspended ceilings, fire extinguishing conduits, ceiling lighting systems and the like, it is customary to mark out fixing or locating positions on the floor surface and then translate these positions to corresponding positions on the ceiling above due to the ease of measuring positions on the floor rather than the ceiling.

Although in some circumstances a plumb bob is a simple and reliable means of establishing vertically aligned reference points, it is time consuming in that two people are often required to use the plumb bob for accurate alignment and marking. Time is also consumed in stabilising any pendulous swing of the plumb bob.

A plumb bob is not effective over large vertical distances, particularly in open buildings or lift wells due to instability arising from wind gusts and draughts.

A self levelling laser device is commonly used in establishing levels for suspended ceilings. The device comprises a powered gyro mechanism for self levelling and is used mostly to generate horizontal lines in a horizontal plane. The apparatus may also be used in a vertical plane to establish reference points for a vertical wall.

SUBSTITUTESHEET The main disadvantages of a self levelling laser device are that it takes some time to stabilise the self levelling gyro mechanism each time the apparatus is repositioned, the apparatus is extremely fragile and expensive to purchase and the apparatus is large and cumbersome and thus is difficult to position relative to existing structures. Another major disadvantage associated with self levelling laser devices is that because they are designed primarily to establish horizontal planes, they are difficult to align with a floor marking to establish a corresponding vertically aligned position on a surface spaced thereabove.

Although such an apparatus could be employed to establish vertically corresponding reference points, this would necessitate "planing" the apparatus through vertical planes at 90° to each other, which process would be extremely time consuming and prone to errors.

Another type of levelling device employed in the building construction industry is a wall mounted infra red radiation emitter. This apparatus is affixed to a wall surface and is levelled by means of a spirit level. A portable infra red receiver is then moved about the surface of spaced or adjoining walls to establish reference points thereon in a horizontal plane. This apparatus is not adaptable to carry out vertical alignment of say a predetermined position on a floor and a corresponding vertically aligned position on a ceiling thereabove.

Yet another type of alignment apparatus comprises a vertically oriented laser tube suspended for vertical alignment under a gravitational force. In this apparatus the laser tube emits a single beam of light upwardly and a lower reference beam is emitted by a high intensity light emitting diode.

A magnetic damping system is employed to stabilise motion in the laser beam and provided that the apparatus is initially set up with adjustable legs to vertically orient the apparatus with a bubble tube leveller, it is claimed that automatic correction is ensured as long as the bubble remains in the range of the circular bubble tube.

While generally satisfactory for its purpose, an apparatus of this type is extremely expensive to manufacture and due to the need for high precision componentry for damping and self correction, it is relatively fragile and easy to damage and thus may require excessive maintenance and recalibration to maintain accuracy. Moreover the use of separate upper and lower reference light beams makes it difficult to obtain initial axial alignment of the beams to obtain the necessary accuracy of say ± 1 mm over 15 metres. Any movement of one light source relative to the other light source due to impact or rough handling is expected to seriously affect the accuracy of this apparatus.

It is an aim of the present invention to overcome or ameliorate the disadvantages of prior art vertical alignment devices and to provide an apparatus which is inexpensive to purchase, robust and easy to use and is able to provide an instantaneous vertical alignment to spaced reference points.

According to the invention there is provided a vertical alignment apparatus comprising:- an electromagnetic radiation transmitter means adapted to transmit beams of electromagnetic radiation coaxially in opposite directions; and, support means adapted to support said transmitter means under the influence of gravity to direct said beams of electromagnetic radiation along a vertical axis.

Preferably said transmitter means comprises spaced, axially aligned transmission apertures with at least one electromagnetic radiation emission means located therebetween.

Suitably said transmitter means comprises a generally tubular body having apertures adapted to direct narrow beams of electromagnetic radiation in coaxially opposite directions. Preferably said transmitter means comprises a single source of electromagnetic radiation.

If required said transmitter means may include focussing and/or collimation means to transmit said electromagnetic radiation as narrow co-axial beams.

Preferably said support means comprises a housing to locate said transmitter means. Suitably said support means includes a levelling means to support said transmitter means under the influence of gravity.

If required said levelling means may include calibration means. Preferably said support means includes locking means to secure said transmitter means within said support means for transportatio .

If required the locking means may comprise an integrated isolating switch means to electrically isolate said transmitter means.

The locking means may comprise a plug and socket engagement.

Suitably the locking means includes a first switch means adapted to maintain a closed circuit coupling for said laser tube under normal operating conditions.

Preferably the locking means includes selectively operable means to induce a magnetic field to disengage said first switch means whe ^" said apparatus is tilted to a predetermined angle. Preferably said housing comprises a protective enclosure with opposed ends thereof transparent to beams of electromagnetic radiation passing therethrough in use.

If required said housing may include adjustable support legs, mounting brackets or the like. According to another aspect of the invention there is comprised a magnetic switch means selectively actuable at a predetermined angle of inclination to isolate an electrical circuit.

In order that the invention may be more clearly understood, reference will now be made to a preferred embodiment illustrated in the accompanying drawings in which

FIG 1 illustrates a side elevational cross sectional

SUBSTITUTESHEET view of one embodiment,

FIG 2 illustrates a part sectional top plan view of the apparatus of FIG 1 ,

FIG 3 illustrates an enlarged view of a gimbal mounted laser transmitter and locking means according to another aspect of the apparatus,

FIG 4 illustrates an alternative view of the locking means of FIG 3,

FIG 5 illustrates schematically an electrical circuit diagram of the apparatus of FIG 3.

FIG 1 illustrates a vertical alignment apparatus 1 which comprises a tubular housing 2 adjustably supported by telescopic support legs 3.

Suspended within housing 2 is a tubular member 4 which is pivotally supported by a gimbal mounting 5 pivotable about perpendicular axes 6 and 7. Gimbal mounting 5 is electrically insulated between housing 2 and tubular member

4.

Within tubular member 4 is located an electrical storage battery 8 and connected to which is an electrical controller 9 to excite a laser tube 10 connected thereto.

Laser tube 10 extends through an aperture 11 in tubular member 4 and is located outside the outer wall 12 of tubular member 4 such that coaxially aligned radiation emission apertures 13, 14 are aligned generally parallel to the outer wall 12.

Located within the base of tubular member 4 is a mass

15, the position of which is adjustable by means of set screws 16 to calibrate tubular member 4 ⁽and thus the radiation emission axes of laser tube 10⁾ to a vertical position.

_An adjustable screw 17 is located in base 18 of housing 2 and engages with a recess 19 in the base 20 of tubular member 4 to lock the tubular member 4 for transportation to 5 prevent damage to the gimbal mount 5 and the laser tube 10.

Housing 2 is sealed at both ends by base 18 and upper cap 21. Within base 18 and cap 21 are transparent apertures 22, 23 respectively, each axially aligned with the transmission axes 24, 15 respectively of laser tube 10. ^Also located in upper cap 21 is an actuating switch 26, a tilt warning indicator lamp 27 and a battery recharging socket 28 (shown in FIG 2) .

Tilt warning indicator lamp 27 is actuated in the event that tubular member 4 comes into contact with housing 2 to indicate that member 4 is not suspended vertically on gimbal mount 5 and thus permits an operator to adjust the telescopic legs 3 to allow free suspension.

Not shown is a de-activating switch for laser controller

9 in the event that the apparatus is accidently knocked onto its side. The de-activating switch is coupled to the tilt warning circuit and thus prevents the laser tube 10 from being energised whilst in a non vertical position.

Similarly, engagement between locking screw 17 and recess 19 also serves to deactivate laser controller 9 to prevent use of the apparatus whilst tubular member 4 is not freely suspended in a vertical position. n use, the apparatus is positioned over a reference point marked on a floor surface and with laser tube 10 energised, is positioned so that the laser beam emerging through aperture 23 in base 20 is located precisely on the marked reference point. The gimbal mounting of tubular member 4 allows rapid stabilisation of tubular member 4 such that the laser beam which emerges along axis 24 exactly locates on an upper ceiling surface a point precisely vertical to the floor reference point.

The ceiling reference point may then be marked and the process repeated for all other floor reference points.

FIG 3 shows an enlarged view of a gimbal mounted laser transmitter and locking mechanism.

In FI_G 3 a helium laser tube 30 is mounted via brackets

31 to a frame member 32 which in turn is suspended from a top 5 cover 33 removably attached to the housing ⁽not shown⁾ of the apparatus. A carry handle 34 offset from laser beam aperture

35 is provided for carrying the apparatus. Frame member 32 is suspended from cover 33 by a gimbal mount 36 having perpendicular pivotal axes 37, 38.

Laser tube 30 includes axially aligned opposed emission apertures 39, 40 and is powered by a power pack 41 comprising a storage battery (not shown) and appropriate electrical circuitry (not shown).

Mounted on the lower end of frame member 32 is a metal block 42 having a central cylindrical aperture 43 opening into a frusto-conical aperture 44. Positioned below block 42 and mounted in association with the housing (not shown) of the apparatus is a locking/deactivating switch 45. Switch 45 comprises a toothed member 46 slidable in a housing 47 and slidable between a fully extended position as shown and a retracted position. The extent of slidable movement is limited by a pin 48 attached to member 46 and slidable in a slotted aperture 49 in housing 47. Member 46 is movable between an extended and retracted position by a rotatable wheel 50 having teeth 51 which engage in the teeth 52 on member 46. The upper portion of member 46 is formed with a frusto- conical neck 53 and a cylindrical plug-like portion 54.

As shown in the extended position, plug-like portion 54 locates within aperture 43 of block 42 and crβvents movement of frame 32 about its gimbal mount 36. A counterweight 55 serves to balance the mass of laser tube 30 s.;^;id its mounting brackets 31.

FIG 4 shows a cross sectional view through A-A of the switch 45. A helical spring 56 engages at its upper end against pin 48 and at its lower end against the core of a permanent magnet 57. The spring urges member 46 to a normally extended position as shown.

A knob 58 mounted on a shaft 59 is provided to rotate toothed wheel 52 (shown in FIG 3) to move the member 46 between the extended position as shown and a retracted position with the lower portion 60 of member 46 located within a recess 61 of magnet 57.

Member 46 is made of a magnetically susceptible material and the biassing force of spring 56 is chosen such that when the lower portion 60 thereof is fully located in recess 61 , member 46 is retained in the retracted position, against the restoring force of spring 56, by permanent magnet 57. 5 FIG 5 illustrates schematically a circuit diagram of the apparatus of FIGS 3 and 4.

A storage or dry cell battery 62 associated with power pack 41 is electrically coupled to laser tube 63 via an isolating switch 64 and control circuitry 65 appropriate for

10 the operation of laser tube 63. A socket 66 is provided for an external power source or for recharging battery 62.

Isolating switch 64 is coupled to the member 46 of FIGS 3 and 4 whereby it is physically closed to excite the laser tube by engagement with a ramp or cam (not shown) associated

15 with member 46 as the plug like portion 54 is withdrawn from aperture 43 during initial rotation of knob 58.

^• Upon continued rotation of knob 58 until member 46 is almost seated within permanent magnet 57, a further switch 67 is then actuated to close one side of a circuit coupled with

20 an electromagnetic coil 68, the purpose of which is described later. With the laser tube excited but otherwise restrained against swinging movement on gimbal mount 36 by the engagement between plug like portion 54 and aperture 43, the apparatus may be moved into position over or beneath a

25 required reference point without undue movement of frame 31.

Knob 58 is then rotated to retract member 46 to enable retention thereof by permanent magnet 57. The frame 31 then swings to a vertical alignment and the apparatus may be carefully moved to align the lower or upper light beams to

30 align with a respective reference point.

In the fully retracted position the tip of plug like portion 54 of member 46 is just clear of cylindrical recess 43 in block 42 such that the upper perimentral edge of portion 54 lies adjacent the surface of frusto-conical recess

3544 near the junction of the wall surfaces of recesses 43 and 44.

If the alignment apparatus is not located on a level

SUBSTITUTESHEET surface or is moved carelessly causing frame 31 to swing sufficiently on its gimbal mount, the plug portion 54 of member 46, which is electrically coupled to electromagnet coil 68, makes a physical contact with the surface of frusto- conical recess and closes the hitherto open circuit coupled to the electromagnetic coil 68.

Energization of coil 68 then induces a magnetic field opposite in polarity to that of permanent magnet 57 whereby the magnetic attraction for member 46 is neutralised or at least reduced sufficiently for the restoring force of spring

56 to drive the plug portion 54 back into cylindrical recess

43.

As the member 46 is restored to its extended position switches 67 and 64 are opened to completely isolate the electrical coupling to the laser tube 63.

The apparatus of FIG 3 is suitably supported within a simple hollow housing of circular or triangular cross-section with three fixed supporting legs.

The apparatus therefor provides a simple yet inexpensive safety isolating switch means which alleviates the possibility of in_jury to the eyes of nearby workers should the apparatus inadvertently be knocked over. Moreover, the isolating switch means embodies a secure mechanical locking means to protect the gimbal mounted laser tube from undue mechanical shock in use and in transportation and storage.

It will be readily apparent that the apparatus according to the invention possesses substantial benefits over prior art apparatus and methods for establishing vertical alignment. The apparatus is simple to use and establishment of vertically corresponding reference points between either floor or ceiling mounted references is extremely rapid and otherwise capable of being used by a single operator instead of two operators hitherto. 5 The apparatus is robust and capable of being operated without any special training for the operator.

It will be equally apparent to a skilled addressee that many a_daptations may be made to the apparatus for use in different circumstances.

For example the apparatus may include castor wheels for mobility, it may include brackets to enable mounting on vertical surfaces or members, mounting on fixed or mobile scaffold frames or building frames such as -wall studs, ceiling joists or rafters etc. The apparatus may be clamped onto pipe work to indicate a vertical pipe run through successive floors in a high rise building thus enabling smaller diameter penetration apertures and perhaps obviating the need for expensive fireproof penetration collars. _in other variations of the invention, the laser tube 10 may be replaced with a source of high intensity visible light or other form of intense electromagnetic radiation emitted as a narrow coherent beam.

In the event that invisible infra-red radiation is employed, a remote portable detector with an audible signalling means can be utilised. Such an apparatus could be used where particular circumstances preclude the use of visible light beams.

Where, due to existing structures, it is not possible to locate the vertical alignment apparatus directly over a reference point. Targets may be clamped or otherwise affixed to a remote structure to indicate the spacing of the desired reference point from that indicated by the laser beam or the like.

If required, the apparatus may include other levelling mechanisms such as a gyroscopic or fluid levelling device.

It will be readily apparent to a skilled addressee that many modifications and variations may be made to the invention without departing from the spirit and scope thereof.

Claims

1. A vertical alignment apparatus comprising:- an electromagnetic radiation transmitter means adapted to transmit beams of electromagnetic radiation coaxially in 5 opposite directions; and, support means adapted to support said transmitter means under the influence of gravity to direct said beams of electromagnetic radiation along a vertical axis.

2. A vertical alignment apparatus as claimed in claim 1 0 wherein said transmitter means comprises spaced, axially aligned transmission apertures with at least one electromagnetic radiation emission means located thereon.

3. A vertical alignment apparatus as claimed in claim 1 or claim 2 wherein said transmitter means comprises a generally 5 tubular body having apertures adapted to direct narrow beams of electromagnetic radiation in coaxially opposite directions.

4. A vertical alignment apparatus as claimed in any one of claims 1 to 3 wherein said transmitter means comprises a

20 single source of electromagnetic radiation.

5. A vertical alignment apparatus as claimed in any preceding claim wherein said transmitter means includes focussing and/or collimation means to transmit said electromagnetic radiation as narrow coaxial beams.

256. A vertical alignment apparatus as claimed in any preceding claim wherein said transmitter means comprises a laser tube.

7. A vertical alignment apparatus as claimed in any one of claims 1 to 6 wherein said support means comprises a gimbal

30 mounting.

8. A vertical alignment apparatus as claimed in any preceding claim including a locking means to selectively secure said support means against movement.

9. A vertical alignment apparatus as claimed in claim 8 35 including means to electrically isolate said transmitter means at a predetermined angle of inclination of said apparatus.

10. A vertical alignment apparatus as claimed in claim 8 or claim 9 wherein said locking means comprises a socket with a frusto-conical aperture therein and a spigot movable between an extended position engaged with said socket and a retracted position in physical disengagement with said socket but located within said frusto-conical aperture.

11. _A vertical alignment apparatus as claimed in any one of claims 8 to 10 wherein said locking means comprises a permanent magnet to retain a slidable member in a retracted position against a restoring influence of a biassing means.

12. _A vertical alignment apparatus as claimed in claim 11 wherein said slidable member is electrically coupled to an electromagnetic coil surrounding said permanent magnet and/or said slidable member, which electromagnetic coil when energised diminishes the magnetically induced retention of said slidable member in a retracted position sufficiently to enable said biassing means to restore said slidable member to an extended position.

13. _A vertical alignment apparatus as claimed in any one of claims 8 to 12 wherein said locking means includes electrical switch means to electrically couple said transmitter means when said slidable member is in a retracted position.

14. _A vertical alignment apparatus as claimed in claim 12 or claim 13 wherein said electromagnetic coil is electrically energised whenever said slidable member is in a retracted position and due to tilting of said apparatus beyond a predetermined angle said slidable member contacts the surface of the frusto conical aperture in said socket.

15. _A vertical alignment apparatus as hereinbefore described with reference to the accompanying drawings.

16. A method of achieving vertical alignment between vertically spaced references utilising a vertical alignment apparatus according to any one of claims 1 to 15.