Abstract:
A survey apparatus which can be used in the underground mining industry comprises a mounting means ( 11 ) adapted to be mounted in a fixed surface (such as a tunnel wall) and an alignement means ( 130, 101 ) to releasably engage with the mounting means ( 11 ), wherein the alignement means ( 130, 101 ) is capable of operating only when the alignement means ( 130, 101 ) is engaged with the mounting means ( 11 ). The mounting means ( 11 ) is preferably a sleeve member ( 11 ) insertable in a wall. The alignement means ( 130, 101 ) preferably has a laser module ( 102 ) and a suitable compartment for accomodating a battery ( 151 ). The mounting means ( 11 ), which is a set aligned in the fixed surface, together with the factory-set alignement means ( 130, 101 ) is used for the purpose of setting out and alignements. When the cylindrical shaft ( 133 ) is inserted into the sleeve member ( 11 ), a rod ( 170 ), permanently in contact with spring ( 154 ) presses against the screw ( 158 ) and makes an electrical connection. As the laser module ( 102 ) cannot be switched on when out of the sleeve member ( 11 ), battery life is improved and improper use is minimized.

Description:
FIELD OF INVENTION 
     The present invention relates to a survey apparatus and a survey method. More particularly, the preferred embodiments of the present invention relate to a laser survey apparatus and a survey method using a laser survey apparatus for use in the underground mining industry. 
     BACKGROUND ART 
     Current methods for the survey control of azimuth and grade in an underground mine during excavation of a tunnel in the mine typically involve the use of survey stations installed in a manner whereby the bearing between the survey stations is generally set to correspond to the bearing of the heading required for excavation. 
     The survey stations are typically comprised of two eye bolts installed in the roof of the heading in the underground mine along the centre line of excavation of the heading. Two wires are usually strung from the eye bolts and have a weight tied to the bottom of each wire. A mine worker can subsequently sight through the wires and mark a centre line at the working face of the excavation. 
     Grade control is usually achieved through the installation of four eye bolts in the walls of the tunnel. These eye bolts are joined in pairs by wires and a mine worker is able to sight through these wires and mark an offset floor height at the working face of the excavation. 
     Unfortunately, the nature of underground mining and the constraints placed upon its workers lead to a variety of problems. 
     The eye bolts are easily damaged by machinery or the destructive effects of blasting. The wires also utilised in the survey stations are commonly broken as a result of not being wound up after use. Further, the ventilation in use in underground mines typically causes the installed wires to sway when hanging from the roof of the heading. This swaying movement results in inaccuracies when sighting. The very method of sighting introduces an unacceptable level of human error and requires operation by particularly skilled workers to be effective. 
     The requirement for the use of wires in current methods can result in a less skilled or an inattentive mine worker incorrectly determining the line and grade in an excavation. 
     Relatively recent developments include the utilisation of lasers for the alignment of development headings. Methods utilising lasers used to this point have been labour and time intensive, and can result in damage to the lasers. In addition, a front target has traditionally been required for accuracy confirmation and adjustment. At least in part because of these reasons, lasers have generally only been used to this point if a heading is going to be beyond a certain length, for example 100 metres. 
     Unfortunately, shorter headings do form the majority of such work. However, some recent work has been conducted utilising pen-sized lasers in headings less than 100 metres. However, the mounting of such a laser on the walls of a heading require brackets and bolting, taking a significant amount of time to set up or establish, are not received easily and are similarly not adjusted easily. 
     The temperamental nature of lasers and their mountings has required complicated checking systems to ensure that the laser has not moved from its original position. 
     Still more recent developments have included the mounting of a laser in a PVC tube of a size big enough to hold the entire laser within the PVC tube, in a pre-drilled aperture in a strata face. The pre-drilled aperture is partially filled with chemical grout and the PVC tube containing the laser is inserted into the aperture. The curing of the grout in this arrangement typically moves the pipe and laser from their original alignment. As such, recalculation of the target is generally required. 
     A further problem associated with this arrangement is the switching on/off of the laser. The mounting method utilised does not allow access to the laser when in position. 
     STATEMENT OF INVENTION 
     The present invention attempts to overcome one or more of the disadvantages of the prior art. 
     According to the present invention there is provided a survey apparatus comprising: 
     a mounting means adapted to be mounted on a fixed object; and 
     an alignment means adapted to releasably engage with the mounting means, 
     wherein the alignment means is capable of operating when the alignment means is engaged with the mounting means. 
     Preferably, the alignment means is provided therein a switch means. The switch means is preferably actuated upon receival of the alignment means in the mounting means, thereby causing operation of the alignment means. 
     The alignment means may include a laser means and the alignment means may also include a battery means. 
     Still further, the alignment means is preferably provided with a mechanism to releasably lock the alignment means in position with respect to the mounting means. 
     The mounting means is preferably formed with a cone-shaped first end to facilitate penetration into an epoxy resin used to locate the mounting means within a fixed surface. An outer surface of the mounting means may be provided with a portion or portions thereof knurled and/or grooved to facilitate grip with the epoxy resin. 
     The mounting means further preferably comprises a biasing means that acts to bias the alignment means out of the mounting means. 
     The alignment means preferably supports the laser means in an adjustable manner, preferably by way of an array of adjustable screws, whereby selective adjustment of the screws being able to adjust alignment of the laser means. 
     According to the present invention there is preferably provided a method of survey control comprising the following steps: 
     making an aperture in a fixed surface for receiving a mounting means; 
     connecting an alignment means to the mounting means, 
     wherein connecting of the alignment means to the mounting means operates the alignment means. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     Preferred embodiments of the present invention will be described below, by way of example only, with reference to the following drawings: 
     FIG. 1 is a perspective exploded view of a preferred embodiment of a sleeve assembly in accordance with the present invention; 
     FIG. 2 is a partial sectional perspective view of the sleeve assembly of FIG. 1; 
     FIG. 3 illustrates a first preferred embodiment of the plug assembly in accordance with the present invention; 
     FIG. 4 shows a second preferred embodiment of the plug assembly in accordance with the present invention; 
     FIG. 5 shows a third preferred embodiment of the plug assembly in accordance with the present invention; 
     FIG. 6 shows a perspective exploded view of a preferred embodiment of the laser housing in accordance with the present invention; 
     FIG. 7 shows a perspective exploded view of a preferred embodiment of switch assembly in accordance with the present invention; 
     FIG. 8 illustrates a perspective exploded view of a preferred embodiment of a switch housing assembly in accordance with the present invention; and 
     FIG. 9 shows details of part of the switch housing assembly of FIG.  8 . 
     FIG. 10 shows the components shown in FIGS. 1 to  9  in an assembled apparatus. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 to  9  show a laser survey apparatus in accordance with the preferred embodiments o f the present invention. 
     The laser apparatus  1  of the preferred embodiment of the present invention is generally comprised mounting means and an alignment means. The mounting means preferably comprises a sleeve assembly  2  as illustrated in FIG.  1 . The alignment means preferably comprises a laser housing assembly  4 , as shown in FIG. 6, and a switch means. The switch means preferably comprises a switch actuating assembly  5 , as shown in FIG. 7, and a switch housing assembly  6 , as shown in FIG. 8. A plug assembly  3  may also be provided as a closure for the sleeve assembly  2 . 
     When assembled, as shown in FIG. 10 the switch actuating assembly  5  is placed within the switch housing assembly  6 . In turn, the switch housing assembly  6  is threadedly engaged with the laser housing assembly  4 . The switch housing assembly  6  is then able to be attached to the sleeve assembly  2  to thereby operate the alignment means. 
     The sleeve assembly  2  will now be described in detail with reference to FIG.  1 . 
     The sleeve assembly  2  is comprised of a sleeve member  11 , a biasing means  12  and a piston member  13 . 
     The sleeve member  11  is shown in more detail in FIG.  2 . The sleeve member  11  is comprised of a sleeve section  14  formed integrally with a cone-shaped end section  15 . At the end of the sleeve section  14  opposite the cone-shaped end section  15 , is provided an opening  16 . The opening  16  is provided with a bevelled edge  17  to assist in the insertion of the switch housing assembly  6  therein, to be described here below. 
     The sleeve member  11  may be formed either of a metallic or synthetic material. The sleeve section  14  preferably has a substantially cylindrical shape. 
     A threaded aperture  18  is preferably provide d proximate the opening  16 . A complimentary threaded screw  19  is capable o f being received within the aperture  18 . It should be noted that the screw  19  may be replaced by a rivet or a dowel in another preferred embodiment of the present invention. In such circumstances, the aperture  18  does not have to be threaded. 
     The sleeve section  14  preferably has a drilled and reamed internal surface for the purposes of ensuring it meets accurate tolerances with the cylindrical shaft  133  of the switch housing assembly  6 , described below. The external surface of the sleeve section  14  preferably has a knurled surface. The knurled surface of the sleeve section  14  assists in the bonding of the sleeve member  11  with the epoxy resin used in mounting t he sleeve member  11  in accordance with the preferred embodiment of the present method of the invention. 
     The cone-shaped end section  15  of the sleeve member  11  is preferably formed integrally with the sleeve section  14 , but may be provided, according to another preferred embodiment of the present invention (not shown), as a separate member. The cone shaped end section  15  is provided with a blunt end  21  having a chamfer  22 . The cone-shaped end section  15  assists in the insertion of the sleeve member  11  into the epoxy resin utilised in the method of the preferred embodiment of the present invention. 
     The piston member  13 , as shown in FIG. 1, preferably has a generally cylindrical shape and adapted to fit within the sleeve section  14 . The piston member  13  is preferably comprised of a first cylindrical portion  25  and a second cylindrical portion  26 . The first cylindrical portion  25  preferably has a greater diameter than the second cylindrical portion  26 . The first cylindrical portion  25  is preferably provided with a groove  27  extending transversely around the circumference of the piston member  13 . An O-ring  28  is preferably provided to sit firmly in the groove  27 . 
     The piston member  13  is preferably provided with an axial aperture  29  extending along the axis X of the piston member  13 . 
     The second cylindrical portion  26  is preferably provided at one end thereof with a slot  30 . Slot  30  preferably intersects the opening of the aperture  29  thereat. 
     A spring locating dowel  31  preferably extends from one end of the first cylindrical portion  25  for the purposes of connection to the biasing means  12 . 
     The sleeve assembly  2  is assembled by placing the biasing means  12 , comprising a spring, inside the sleeve section  14  of the sleeve member  11 . 
     The piston member  13  is then placed in the sleeve member  11  so that it can slide within sleeve section  14 . Once the piston member  13  is inside the sleeve section  14 , the screw  19  is screwed into the aperture  18  to retain the piston member  13  within the sleeve section  14  as a result of a shoulder section  32  of the first cylindrical portion  25  abutting against the screw  19  when it extends inside the sleeve section  14 . 
     The piston member  13  is biased against the screw  19  as a result of the biasing means  12  acting in the direction away from the blunt end  21  against the piston member  13 . 
     The piston member  13  may be manufactured from either a metallic or synthetic material. 
     Once installed as described above, the piston member  13  preferably acts substantially to seal the sleeve section  14  from the outside by way of the O-ring  28  located in the groove  27  of the piston member  13 . 
     The axial aperture  29  and the slot  30  in the piston member  13  preferably act as an air bleed from the inside of the sleeve section  14  when the piston member  13  is pressed into the section  14 . 
     In use, the sleeve assembly  2  is placed in an aperture and fixed in the aperture with a resin material, as will be described below. 
     A first preferred embodiment of the plug assembly  3  will now be described with reference to FIG.  3 . 
     The plug assembly  3  in FIG. 3 is comprised of a plug  42  adapted to fit firmly into the opening  16  of the sleeve member  11 . The plug  42  is preferably provided with an aperture  46  in the centre thereof through which a string  41  is able to pass. The string  41  is provided with heat sealed ends  43  and  44 . 
     The string  41  is capable of sliding inside the aperture  46  but the ends  43  and  44  prevent the string  41  from sliding completely out of the aperture  46 . 
     The plug  42  is preferably provided with a thumb pressed top  45  for pressing the plug  42  into the opening  16 . The top  45  is preferably provided with a non sharp edge  47 . 
     The plug  42  is provided with a seating flange  48  having a radiused rim  49  for easy insertion into the opening  16 . The seating flange  48  is preferably provided with over-diameter portion  50  for engaging the plug  42  in the sleeve member  11 . 
     A second preferred embodiment of the plug assembly  3  will now be described by reference to FIG.  4 . Like features to that shown in FIG. 3 have been given the same numbering and will not be described again. 
     The plug  42  of this preferred embodiment is provided with a tapered portion  55  which tapers down to a threaded portion  52 . The threaded portion  52  allows the thread to be screwed about the screw  19  of the sleeve member  11 . By screwing the plug  52  into the opening  16 , the threaded portion  52  engages with the screw  19  to lock the plug  42  into the opening  16 . 
     The aperture  46  of this preferred embodiment also widens to provide a volume  52  in which to receive second cylindrical portion  26  of the piston member  13  of the sleeve assembly  2 . 
     An O-ring  56  may also be provided to be positioned on O-ring seat  53  to assist in sealing the opening  16  when the plug  42  is placed in the opening  16 . 
     A third preferred embodiment of plug assembly  3  will now be described by reference to FIG.  5 . Again, like features have been given the same numbering. 
     In this preferred embodiment a flat portion  58  is provided on one end of the plug  42  along with a groove  57 . Another flat position may be provided on the opposite side. When inserting the plug  42  into the opening  16 , the flat portion  58  passes the screw  19  in the sleeve member  11  and can then be rotated to lock into the groove  57 . 
     In use, the end  43  of the string  41  is embedded in the resin material in which the sleeve assembly  2  is placed. Thus, when the plug is taken out of the opening  16 , the plug is suspended from the wall by the string  41  so that it is not lost. 
     A preferred embodiment of the laser housing assembly  4  will now be described with reference to FIG.  6 . 
     The laser housing assembly  4  is preferably comprised of a housing section  101 , a laser module  102 , a spacer  103 , a lens  106  and screws  113 . 
     The housing section  101  preferably has a generally cylindrical shape and has a first end  104  and a second end  105 . 
     The first end  104  is preferably provided with a lens  106  which is received within a recess  107  provided at the first end  104  of the housing section  104 . 
     The first end  104  is provided with a shoulder  108  extending inside the housing section  101  perpendicular to the central axis Y of the housing section  101 . The shoulder  108  has an outer surface  109  which is perpendicular to the central axis Y and an inner surface  110  which is sloped relative to the central axis Y. 
     When assembled, the lens  106  is placed in the recess  107  to abut the outer surface  109  of the shoulder  108  to thereby press fit the lenses  106  in the recess  107 . 
     The first end  104  preferably has a chamfered edge so that the housing section  101  does not have a sharp edge. 
     The housing section  101  is preferably provided with a cylindrical cavity  111  for receiving the laser means comprising a laser module  102 . The cavity  111  preferably has a diameter larger than the diameter of the laser module  102  so that the laser module  102  can move freely inside the cavity  111 . 
     Threaded apertures  112  are preferably provided in the housing section  101  to extend into the cavity  111 . The threaded apertures  112  are preferably adapted to receive adjustment means comprising screws  113  in each of the apertures  112 . The apertures  112  are preferably arranged around the cavity  111  in a concentric manner. 
     When the laser module  102  is placed in the cavity  111 , the screws  113  are placed in the apertures  112  and the screws  113  are adjusted to abut against the laser module  102  and to hold it in place in the cavity  111 . The laser module  102  is thereby restrained from lateral movement within the cavity  111  by the inner surface  110  of the shoulder  109  and the screws  113 . The alignment of the laser module  102  can be adjusted by adjusting the screws  113 . 
     The housing section  101  is further preferably provided with an insulator seat section  116  for receiving the insulator  103  with press fit engagement. A bevelled edge  117  is provided adjacent the insulator seat section  116  to assist in the transition of the insulator  103  into the insulator seat section  116 . 
     In use, the insulator  103  is press fitted into the insulator seat section  116 . An aperture  115  is preferably provided in the insulator  103  through which a spring  114  is able to pass. The insulator  103  and spring  114  function in part to protect the laser module  102  from impact by the battery to be described hereinafter. 
     The second end  105  of the housing section  101  is preferably provided at its inner edge with an alignment shoulder  122  for engagement with the switch housing assembly  6 , to be described below with reference to FIG.  8 . 
     An O-ring seat section  121  is preferably provided adjacent to the alignment shoulder  122  for receiving O-rings  147  of the switch housing assembly  6 , to be described below with reference to FIG.  8 . 
     A threaded section  120  preferably extends from the O-ring section  121 . The threaded section  120  is provided for engagement with threaded portion  148  of the switch housing assembly  6 , to be described below with reference to FIG.  8 . 
     Adjacent to the bevelled edge  117  is preferably provided an alignment shoulder  118  for engagement with smooth portion  149  of the switch housing assembly  6 , to be described below with reference to FIG.  8 . 
     The preferred embodiment of the switch housing assembly  6  of the present invention will now be described with reference to FIGS. 8 and 9. 
     The switch housing assembly  6  is preferably comprised of a housing body  130  which may be manufactured from a metallic or artificial material. The housing body  130  preferably has a first end  132  and a second end  131 . The first end  132  is preferably comprised of a cylindrical shaft  133  and the second end  131  is preferably comprised of a cylindrical portion  134  which has a much larger diameter than the diameter of the cylindrical shaft  133 . 
     The cylindrical shaft  133  is preferably adapted for engagement with the sleeve assembly  2  such that the cylindrical shaft  133  is capable of a snug and aligned fit inside the sleeve section  14  of the sleeve member  11 . The first end  132  is preferably provided with a radiused outer surface  135  to assist in the insertion of the cylindrical shaft  133  in the sleeve section  14  of the sleeve assembly  2 . 
     The first end  132  is also preferably provided with chamfered edge  136  for engagement of the cylindrical shaft  133  with the piston member  13  of the sleeve assembly  2 . 
     The cylindrical shaft  133  is preferably provided with an internal bore  137  extending from the first end  132  along the centre axis Z of the switch housing assembly  6 . The bore  137  is adapted to receive the elongated rod  170  of the switch actuating assembly  5 . The bore  137  preferably has a widened section  138  to accommodate the further  173  of the switch actuating assembly  5  and a second widened section  139  for housing the biasing means  171  of the switch actuating assembly  5 . 
     The cylindrical shaft  133  is further preferably provided with a locking means comprising a longitudinal groove  140  extending along the length of the cylindrical shaft  133 . The groove  140 , as shown in more detail in FIG. 9, is preferably a bull nosed groove for engagement with the screw  19  of the sleeve assembly  2  when the cylinder shaft  133  of the switch housing assembly  6  is inserted into the sleeve assembly  2 . A larger bull nosed groove opening  141  is preferably provided at the start of the groove  140  for easy engagement of the groove  140  with the screw  19 . The groove  140  is preferably pitched so that the switch housing assembly  6  rotates as it is inserted into the sleeve assembly  2  to impose the support of the cylindrical shaft  133  of the switch housing assembly  6 . 
     The upper end  142  of the groove  140  preferably forms a transverse groove so that, in use, when the cylindrical shaft  130  of the switch housing assembly  6  is inserted into the sleeve assembly  2 , the screw  19  slides along the groove  140  and engages the screw  19  into the upper end  142  of the groove  140  so that the cylindrical shaft  130  of the switch housing assembly  6  is locked in to the sleeve assembly  2 . The switch housing assembly  6  can then be disengaged from the sleeve assembly  2  by rotating the switch housing assembly  6  until the screw  19  disengages from the upper end  142  of the groove  140  so that the screw  19  can slide along the groove  140  and disengage from the switch housing  6 . 
     The end of the cylindrical shaft  133  opposite to the end  132  is preferably formed integral with a frusto-conical section  143  which is formed, in turn, integrally with an externally knurled portion  144 . The edge of the knurled portion  144  is preferably provided with a raised shoulder  145  to assist alignment with the housing section  101  of the laser housing assembly  4 . 
     The housing body  130  is further preferably provided with a groove  146  for receiving 2 O-rings  147  for sealing and gripping to the laser housing assembly  4 . 
     An externally threaded portion  148  is provided adjacent to the groove  146  and the second end  131  preferably terminates in an externally smooth portion  149  which is adapted to assist in aligning the laser housing assembly  4  with the switch housing assembly  6 . 
     Cylindrical portion  134  preferably forms a battery cavity  150  in which can be received a battery module  151 . 
     The cylindrical portion  134  further defines a switch cavity  153  formed in the frusto-conical section  143 . 
     The switch housing assembly  6  is further provided with an electrical contact  154  preferably comprised of a stainless steel conical spring capable of completing an electric circuit between the battery module  151  and the housing body  130 . When assembled, the contact  154  sits in the switch cavity  153  and a nylon insulator and switch seal  156  is press fitted into an insulator portion  155  of the housing body  130 . 
     The insulator  156  is preferably provided with a threaded aperture  157  for receiving a stainless steel adjustable electrical contact screw  158 . 
     The battery module  151  is preferably provided with a positive terminal  159  in a position whereby the contact  154  can make electrical contact with the terminal  159  through screw  158 . To thereby complete an electrical circuit between the housing body  130  and the battery module  151 . 
     The switch actuating assembly  5  will now be described by reference to FIG.  7 . 
     The switch actuating assembly  5  is preferably comprised of an elongated rod  170 , a bias means  171 , a ferrule  172  and O-rings  178  and  182 . 
     The electrical rod  170  is adapted to pass through the bore  137  of the cylindrical shaft  133 . 
     The ferrule  172  is adapted to be located in the widened section  138  of the switch housing assembly  6  described above. The switch actuating assembly  5  may be manufactured from a metallic or synthetic composition. 
     The ferrule  172  has a cylindrical portion  173  with a chamfered edge  174  at both ends. A partially threaded aperture  175  is provided at the end for engagement with a threaded end  176  of the rod  170 . 
     A groove  177  is preferably provided in the ferrule  172  to receive 2 O-rings  178 . 
     An hexagonal switch retaining flange  179  is provided at the other end of the rod  170  to the threaded end  176 . The flange  179  forms a seating point  181  with the rod  170  for the contact  154  of the switch housing assembly  6 . The top of the rod  170  provides an electrical contact point  181  for making electric contract with the screw  158  of the switch housing assembly  6 . 
     There is further preferably provided an O-ring  182  for providing additional sealing and spacing from the bore  137 . 
     When assembling, as shown in FIG. 10, the various features described above, the ferrule  172  of the switch actuating assembly  5  is housed in the widened section  138  of the switch housing assembly  6 . The rod  170  is provided to extend through the internal bore  137  of the housing body  130  of the switch housing assembly  6 . The biasing means  171  of the switch actuating assembly  5  sits in the widened section  139 . The O-ring  182  is housed within the switch cavity  153 . 
     As the shaft  133  is inserted into the sleeve member  11  of the sleeve assembly  2 , the rod  170  moves inwardly with respect to the shaft  133  causing the seating point  180  to contact the biasing means  154  and the screw  158  of the switch housing assembly  6 . This creates an electric circuit connection to the positive terminal  59  of the battery module  151 . The current generated flows from the battery module  151  to the laser module  102 . In this manner, the laser module  102  is automatically turned on once the switch housing assembly  6 , switch actuating assembly  5  and the laser housing assembly  6  are received by the sleeve assembly  2 . 
     When the shaft  133  of the switch housing assembly  6  is withdrawn from the sleeve  11 , the spring  171  of the switch actuating assembly  5  biases the rod  170 , thus returning it to a position in which the O-ring  182  and flange  179  abuts the shoulder  182  in the bore  137 . In this position the switch actuating assembly  5  no longer causes electrical contact with the battery module  151 . 
     According to the method of the preferred embodiment of the present invention, the laser apparatus  1  of the present invention is used by drilling a small aperture (not shown) in a fixed surface where the apparatus  1  is to be located. The aperture is then partially filled with an epoxy resin and the sleeve assembly  2  is inserted into the aperture. Further epoxy resin is to be inserted to completely fill the aperture. The assembly  2  is thus affixed inside the surface by means of the setting epoxy resin. 
     The plug assembly  3  may also be affixed to the surface by setting the string  41  in the epoxy resin. The plug assembly  3  can then be used to close the sleeve assembly  2  to prevent the entry of dirt. 
     When the apparatus is to be used, the switch actuating assembly  5  is connected to the switch housing assembly  6  and the switch housing assembly  6  and laser housing assembly  4  are connected to each other. 
     The plug assembly  3  is then removed from the sleeve assembly  2  and the cylindrical shaft  133  of the switch housing assembly  6  is inserted in the sleeve assembly  2  and locked thereto. As the cylindrical shaft  133  is inserted into the sleeve assembly  2 , the second cylindrical portion  26  of the piston member  13  presses against the ferrule  173 . This pushes the rod  170  upwards along the bore  137  so that the seating point  180  of the switch actuating assembly  5  moves upwards to press against the contact  154  and the screw  158 . This results in making an electrical connection between the screw  158 , the positive terminal  159  of the battery module  151 , the laser module  102 , the screws  113 , the housing section  101 , the housing body  130 , the contact  154  and back to the seating point  180 . This causes laser light to be produced out of the lense  106  for setting out purpose. 
     When the setting out is completed, the laser housing assembly  4 , switch actuating assembly  5  and switch housing assembly  6  are removed from the sleeve assembly  2 , which removal causes the laser module  102  to be switched off. 
     The preferred embodiments of the present invention as described above provides various advantages over the known prior art. 
     For example, by having the apparatus including the laser module and the battery module not housed in the wall, a smaller and easier to drill aperture can be made for receiving the sleeve assembly using a small portable battery drill. Therefore, only a small sleeve assembly needs to be inserted into the wall while the apparatus can be simply attached to the sleeve, but is positioned outside of the sleeve assembly. 
     By having a means of switching the laser module on when inserting into the sleeve, the preferred embodiment of the present invention improves the battery life and improper use is minimised since the apparatus is not inadvertently left on and cannot accidentally be switched on when out of the sleeve. 
     Furthermore, by providing the longitudinal and transverse groove in the shaft to attach the alignment means to the sleeve in accordance with the preferred embodiment of the present invention, the apparatus can be quickly installed and removed. By pitching the groove with respect to the centre line, it will prevent the apparatus from rocking along the centreline within the sleeve, that is, opposite ends of the shaft are supported by the pitched groove on the inside of the sleeve. 
     By providing the plug assembly according to the preferred embodiment of the present invention, it is possible substantially to prevent foreign particles from entering the sleeve, however by using the piston member in accordance with the preferred embodiment, foreign particles built up within the more inaccessible internal areas of the sleeve should be easily ejected. 
     Furthermore, by using an epoxy resin to encase the sleeve within the wall in accordance with the preferred embodiment, the apparatus can be brought into both horizontal and vertical alignment before the epoxy resin sets and thus retain the intended alignment. 
     The screw  19  in the sleeve according to the preferred embodiment of the present invention provides several advantages, including retaining the piston member within the sleeve, locking the cylindrical shaft of the alignment means quickly within the sleeve, providing adjustment clearance at manufacture within the sleeve and to hold the plug in position. 
     The piston member inside the sleeve assembly in accordance with the preferred embodiment of the present invention provides various advantages including ejecting the shaft from the sleeve, preventing dirt from entering the sleeve and ejecting dirt from the sleeve, and activates the laser module when the switch activating means engages with the piston member. 
     The apparatus of the preferred embodiment of the present invention can replace the equipment of the survey stations of the prior art, thereby removing the various disadvantages of suspended wires, grade lines, grade sticks, etc. 
     Apart from these improvements, the apparatus according to the preferred embodiment of the present invention also provides major costs savings as a single person can carry out the marking of mine excavation faces, more accurate alignments of the excavation designs can be achieved which in turn reduces the costs associated with misaligned mark-ups. 
     Costs are also saved as the preferred embodiment removes traditional sighting inaccuracies associated with prior art methods and removes the need for costly floor and wall stripping. Less explosives, time, bogging, machinery costs, labour costs are incurred whilst providing longer sighting ranges. As the switch housing assembly carries its own battery there is no need for external wiring or batteries. The apparatus is such that the mine workers can use the system without the presence of the surveyor, leaving the surveyor to attend to other functions, thereby reducing costs. 
     Still further, surveyors will not be required to regularly replace eye bolts damaged by blasting or machinery. Mine workers can also continue working without having to estimate alignment on a continual basis. 
     Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention. 
     Throughout the specification, unless the context requires otherwise, the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.