Abstract:
A laser surveying apparatus includes: a laser light source configured to emit a laser light flux; a laser projector supported tiltably and configured to rotatably irradiate the laser light flux emitted from the laser light source; a mechanism tiltably supporting the laser projector; tilting arms extending in an X-direction and a Y-direction substantially perpendicular to the laser projector; a tilt driving section provided to at least one of the tilting arms configured to drive corresponding at least one of the tilting arms; detectors provided to each of the tilting arms and each configured to detect a movement amount of the corresponding one of the tilting arms, and an arithmetic section configured to calculate an inclination of the laser projector in the X-direction and the Y-direction from each of the movement amounts of the tilting arms detected by the corresponding detectors.

Description:
BACKGROUND  
       [0001]     The present invention relates to a surveying apparatus. More particularly, the present invention relates to an improvement in a surveying apparatus in which a laser projector is supported by a gimbal mechanism so as to tilt the laser projector.  
         [0002]     In a conventional laser surveying apparatus, such as the laser surveying apparatus disclosed in JP-H06-26861A for example, a perforated concave portion having a hemispherical configuration is formed in the center of a casing  50 , and a laser projector  51  which emits a laser beam is tiltably engaged freely and supported by the concave portion.  
         [0003]     A head of the laser projector  51  is provided with a prism supporting body  52  which rotates around the center of axle of the laser projector  51 . A scan gear is fitted to the prism supporting body  52 , so that the prism supporting body  52  is adapted to rotate around the center of axle of the laser projector  51  by a scan motor  53 ′ through the scan gear. Thus, the prism supporting body  52  and the scan gear structure a rotation section  53 .  
         [0004]     The prism supporting body  52  is also provided with a pentaprism  54 . The pentaprism  54  orthogonally deflects the laser beam emitted from a direction of the center of axle of the laser projector  51  so as to project the laser beam in a horizontal direction.  
         [0005]     In a midway part of the laser projector  51  protruded from the concave portion, a fixed bubble tube  55  and a fixed bubble tube  56 , structuring an inclination detector for detecting an inclination of the laser projector  51 , are provided orthogonally to each other in such a manner as to be perpendicular to the center of axle of the laser projector  51 , to detect verticality of the laser projector  51 .  
         [0006]     A lower end part of the laser projector  51  is provided with a base plate  57  provided tiltably in a direction perpendicular to the laser projector  51 . An arbitrary angle setting bubble tube  58  and an arbitrary angle setting bubble tube  59 , both adapted to detect the inclination of the laser projector  51 , are provided on the base plate  57 .  
         [0007]     The base plate  57  is tilted by an arbitrary angle setting driving section  60  and an arbitrary angle setting driving section  61 . Note that a tilting direction of the base plate  57  and directions to which the arbitrary angle setting bubble tubes  58  and  59  are provided correspond to a tilting direction of the laser projector  51 .  
         [0008]     Tilting arm  62  and tilting arm  63  for tilting the laser projector  51  are protruded and extended from the laser projector  51  orthogonally in a horizontal direction, respectively. The tilting arms  62  and  63  are engaged with tilt driving sections  64  and  65  through engagement pins, respectively.  
         [0009]     Now, leveling for setting the laser projector  51  vertically in accordance with the conventional laser surveying apparatus will be described.  
         [0010]     The tilt driving sections  64  and  65  are driven until each of the fixed bubble tubes  55  and  56  detects horizontality based on a result of detection of each of the fixed bubble tubes  55  and  56 , so as to compensate the inclination of the laser projector  51 . When the fixed bubble tubes  55  and  56  have detected the horizontality, the center of axle of the laser projector  51  is leveled vertically.  
         [0011]     Next, inclination setting for freely tilting the laser projector  51  in arbitrary directions in accordance with the conventional laser surveying apparatus will be described. At first, setting of the inclination of the laser projector  51  in an X-direction or a first direction will be explained.  
         [0012]     The arbitrary angle setting driving section  60  is actuated to tilt the base plate  57  in the X-direction or the first direction at an arbitrary angle. The arbitrary angle setting driving section  60  is used to set a predetermined angle of inclination of the laser projector  51  based on the number of drive pulses. Then, the tilt driving section  64  is actuated based on a result of detection of the arbitrary angle setting bubble tube  58  until the tilted arbitrary angle setting bubble tube  58 , provided in the X-direction, detects the horizontality, so as to tilt the laser projector  51 . When the arbitrary angle setting bubble tube  58  has detected the horizontality, the laser projector  51  is set at the predetermined angle of inclination.  
         [0013]     Furthermore, the other arbitrary angle setting driving section  61 , the arbitrary angle setting bubble tube  59  and the tilt driving section  65 , which are perpendicular to the arbitrary angle setting driving section  60 , the arbitrary angle setting bubble tube  58  and the tilt driving section  64 , respectively, are similarly activated to detect the horizontality in a Y-direction or a second direction. Thereby, the inclination setting of the laser projector  51  in two directions is possible.  
         [0014]     However, because the conventional laser surveying apparatus including the laser surveying apparatus disclosed in JP-H06-26861A employs a pivot structure in which the laser projector or a laser projecting section is supported by the hemispherical concave portion, there is a problem that, although it has the reduced play, a wide range of inclination of the laser projector cannot be obtained structurally.  
         [0015]     In addition, there has been also known a laser surveying apparatus which employs a structure in which a laser projector is supported by a gimbal mechanism and a tilting mechanism is utilized to tilt the laser projector. In the conventional laser surveying apparatus utilizing the gimbal mechanism, however, it cannot prevent generation of the play in a bearing part of the gimbal mechanism. Therefore, the conventional laser surveying apparatus utilizing the gimbal mechanism is not suitable for the purpose requiring a precise angle of tilt of the laser projector.  
       SUMMARY  
       [0016]     At least one objective of the present invention is to provide a laser surveying apparatus capable of setting a tilt angle of a laser projector precisely, even when a structure having the play is employed.  
         [0017]     To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a laser surveying apparatus, comprising: a laser light source configured to emit a laser light flux; a laser projector supported tiltably and configured to rotatably irradiate the laser light flux emitted from the laser light source; a mechanism tiltably supporting the laser projector; tilting arms extending in an X-direction and a Y-direction substantially perpendicular to the laser projector; a tilt driving section provided to at least one of the tilting arms configured to drive corresponding at least one of the tilting arms; detectors provided to each of the tilting arms and each configured to detect a movement amount of the corresponding one of the tilting arms, and an arithmetic section configured to calculate an inclination of the laser projector in the X-direction and the Y-direction from each of the movement amounts of the tilting arms detected by the corresponding detectors.  
         [0018]     In accordance with an embodiment of the invention, each of the detectors is configured to detect the movement amount of the corresponding one of the tilting arms by detecting a movement amount of the tilt driving section engaged with the at least one of the tilting arms.  
         [0019]     In accordance with an embodiment of the invention, the mechanism comprises a gimbal mechanism configured to tiltably support the laser projector, and the arithmetic section is configured to detect an error caused by play of the gimbal mechanism from the movement amount of each of the tilting arms detected by the corresponding detectors.  
         [0020]     In accordance with an embodiment of the invention, the mechanism comprises a gimbal mechanism configured to tiltably support the laser projector, and the laser surveying apparatus further comprises: a first pair of shafts each extending in directions opposite to each other in one of the X-direction and the Y-direction and configured to rotatably support a body of the gimbal mechanism, and a second pair of shafts each extending in directions opposite to each other in the other of the X-direction and the Y-direction, and an intersection point of an axis line connecting each of the shafts of the first pair of shafts and an axis line connecting each of the shafts of the second pair of shafts is a center of tilt of the laser projector.  
         [0021]     In accordance with an embodiment of the invention, the tilt driving section is provided to each of the tilting arms, and each of the tilt driving sections comprises: a drive motor; a rod screw driven by the drive motor; and a slider engaged with the corresponding one of the tilting arms and configured to reciprocate by the rod screw in a direction to which the rod screw extends.  
         [0022]     In accordance with an embodiment of the invention, each of the detectors faces corresponding one of the sliders of the tilt driving sections and comprises a linear detector configured to optically detect a movement amount of the corresponding one of the sliders.  
         [0023]     In accordance with an embodiment of the invention, the arithmetic section is configured to calculate a tilt angle from a horizontal plane of the laser projector based on the movement amount from a reference position of each of the sliders and distances from a center of tilt of the laser projector to each of the rod screws.  
         [0024]     In accordance with an embodiment of the invention, each of the detectors faces an end of the corresponding one of the tilting arms and comprises a linear detector configured to optically detect the movement amount of the corresponding one of the tilting arms.  
         [0025]     In accordance with an embodiment of the invention, the second pair of shafts is protruded from the laser projector.  
         [0026]     In addition, the present invention provides another a laser surveying apparatus, comprising: a laser light source configured to emit a laser light flux; a laser projector supported tiltably and configured to rotatably irradiate the laser light flux emitted from the laser light source to form a rotation reference plane; a gimbal mechanism having a frame body and configured to tiltably support the laser projector in an X-direction and a Y-direction perpendicular to each other; a casing accommodating therein the gimbal mechanism; a first pair of shafts each extending from the frame body of the gimbal mechanism to the casing in directions opposite to each other in one of the X-direction and the Y-direction and configured to rotatably support the frame body of the gimbal mechanism, and a second pair of shafts each extending from the frame body of the gimbal mechanism in directions opposite to each other in the other of the X-direction and the Y-direction and configured to support the laser projector, a tilting mechanism provided in the casing and configured to tilt the laser projector; and an arithmetic section configured to calculate a tilt angle of the laser projector, the tilting mechanism including: a first pair of tilting arms each extending in directions opposite to each other in the X-direction from the laser projector; a second pair of tilting arms each extending in directions opposite to each other in the Y-direction from the laser projector; first tilt driving sections each configured to drive corresponding one of the tilting arms of the first pair of tilting arms; second tilt driving sections each configured to drive corresponding one of the tilting arms of the second pair of tilting arms; first detectors each configured to detect a tilt amount of the corresponding one of the tilting arms of the first pair of tilting arms; and second detectors each configured to detect a tilt amount of the corresponding one of the tilting arms of the second pair of tilting arms, the arithmetic section being configured to calculate the tilt angle of the laser projector according to an output of detection of the tilt amount of each of the first detectors and the second detectors.  
         [0027]     In accordance with an embodiment of the invention, an intersection point of an axis line connecting each of the shafts of the first pair of shafts and an axis line connecting each of the shafts of the second pair of shafts is a center of tilt of the laser projector.  
         [0028]     In accordance with an embodiment of the invention, each of the tilt driving sections comprises: a drive motor; a rod screw driven by the drive motor; and a slider engaged with the corresponding one of the tilting arms and configured to reciprocate by the rod screw in a direction to which the rod screw extends.  
         [0029]     In accordance with an embodiment of the invention, each of the detectors faces the corresponding one of the sliders of the tilt driving sections and comprises a linear detector configured to optically detect a movement amount of the corresponding one of the sliders.  
         [0030]     In accordance with an embodiment of the invention, the arithmetic section is configured to calculate the tilt angle from a horizontal plane of the laser projector based on the movement amount from a reference position of each of the sliders and distances from a center of tilt of the laser projector to each of the rod screws.  
         [0031]     In accordance with an embodiment of the invention, each of the detectors faces an end of the corresponding one of the tilting arms and comprises a linear detector configured to optically detect the tilt amount of the corresponding one of the tilting arms.  
         [0032]     Therefore, according to the laser surveying apparatus of the present invention, because the structure in which the inclination of the tilting mechanism of the laser projector is read directly in an opposed manner is employed, it is possible to set the accurate angle of inclination even when there is the play in the laser projector and its supporting mechanism. In addition, since the supporting mechanism in which the large angle of inclination can be obtained such as the gimbal supporting mechanism is possible to be employed, it is possible to widen the range of inclination of the laser projector.  
         [0033]     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0034]     The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.  
         [0035]      FIG. 1  is a partial cross-sectional side view illustrating a main part of a gimbal mechanism of a laser surveying apparatus according to an embodiment of the invention, in which a relation of supporting between the gimbal mechanism and a laser projector, seen from a direction perpendicular to an X-Z plane, is illustrated.  
         [0036]      FIG. 2  is a plan view illustrating the relation of supporting between the gimbal mechanism and the laser projector illustrated in  FIG. 1 .  
         [0037]      FIG. 3  is a partial cross-sectional view illustrating a relation among the gimbal mechanism, the laser projector illustrated in  FIG. 1  and a tilting mechanism, seen from a direction perpendicular to the X-Z plane.  
         [0038]      FIG. 4  is a view illustrating the relation among the gimbal mechanism, the laser projector and the tilting mechanism illustrated in  FIG. 3 , seen from the direction perpendicular to an X-Y plane.  
         [0039]      FIG. 5  is a view illustrating a driving section of the tilting mechanism illustrated in  FIG. 3 .  
         [0040]      FIG. 6  is a view illustrating the relation among the gimbal mechanism, the laser projector and the tilting mechanism illustrated in  FIG. 3 , seen from the direction perpendicular to the Y-Z plane.  
         [0041]      FIG. 7  is an explanatory view illustrating an example of calculation for obtaining a tilt angle of the laser projector illustrated in  FIG. 1 , and also illustrates a relation between distances from the center of tilt of the laser projector to rod screws in a horizontal direction and movement amounts of sliders.  
         [0042]      FIG. 8  illustrates a main structure of a conventional laser surveying apparatus. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0043]     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. The scope of the present invention, however, is not limited to these embodiments. Within the scope of the present invention, any structure and material described below can be appropriately modified.  
         [0044]     Referring to  FIG. 1 , a reference numeral  1  denotes a casing of a surveying apparatus. A lower part of the casing  1  is provided with leveling screws  2 . The leveling screws  2  function to adjust the casing  1  to be placed horizontally.  
         [0045]     As illustrated in  FIG. 2 , inside of the casing  1  is provided with a gimbal mechanism  3 . The gimbal mechanism  3  according to the present preferred embodiment of the invention is structured by a rectangular outer frame  4 , and a rectangular inner frame  5  surrounded by the outer frame  4 .  
         [0046]     Referring to  FIG. 2 , the outer frame  4  includes a pair of parallel plates  4   a  extending in an X-direction, and a pair of parallel plates  4   b  extending in a Y-direction. The outer frame  4  is fixed to the casing  1 . The inner frame  5  includes a pair of parallel plates  5   a  extending in the X-direction, and a pair of parallel plates  5   b  extending in the Y-direction.  
         [0047]     The pair of parallel plates  5   b  of the inner frame  5  is protrudedly formed with a pair of shafts  6  each positioned symmetrical with an optical axis O (or a “Z”-direction) of a later-described laser projector as an axis of symmetry. Each of the shafts  6  extends in a direction opposite to each other in the X-direction. The shafts  6  are rotatably supported by the parallel plates  4   b  of the outer frame  4  through bearings, respectively. In the present preferred embodiment, a ball bearing  7   a  is used as the bearing, although it is not limited thereto.  
         [0048]     The laser projector  8  is provided in the inner frame  5 . The laser projector  8  is protrudedly formed with a pair of shafts  9  each positioned symmetrical with the optical axis O of the laser projector  8  as an axis of symmetry. Each of the shafts  9  extends in a direction opposite to each other in the Y-direction. The shafts  9  are rotatably supported by the parallel plates  5   a  of the inner frame  5  preferably through ball bearings  7   b,  respectively, although it is not limited thereto.  
         [0049]     According to the present preferred embodiment, an intersection point of an axis line K 2  connecting each of the shafts  6  and an axis line K 1  connecting each of the shafts  9  is set as the center of tilt of the laser projector  8 .  
         [0050]     Turning to  FIG. 1 , a bottom part of the laser projector  8  is provided with a laser light source  10 . An upper part of the laser projector  8  is provided with a rotation cylinder  11 , which is provided rotatably. Inside of the rotation cylinder  11  is arranged with a pentaprism  12 . In addition, an upper outer circumferential part of the laser projector  8  is attached with a drive motor  13  through a bracket  14 . Moreover, a lower part of the rotation cylinder  11  is arranged with a gear  15 , withwhich an output gear  16  of the drive motor  13  is engaged.  
         [0051]     As illustrated in  FIGS. 3 and 4 , the laser projector  8  is formed with a pair of tilting arms  17  each positioned symmetrical with the optical axis O of the laser projector  8  as an axis of symmetry, and each of the tilting arms  17  extends in a direction opposite to each other in the X-direction. Referring to  FIG. 3 , leading ends extending mutually in the opposite directions of the tilting arms  17  are bent downwardly preferably at a right angle, respectively, and lower ends in the bent-directions of the tilting arms  17  are arranged with engagement pins  17   a  each protruded in a direction opposite to each other, respectively. In the present preferred embodiment, the pair of tilting arms  17  structures a part of a Z-X in-plane tilting mechanism configured to tilt the laser projector  8  in the X-direction in a Z-X plane.  
         [0052]     The Z-X in-plane tilting mechanism includes drive motors  18  each structure a part of a tilt driving section as illustrated in  FIG. 5 . The drive motors  18  are fixed to appropriate parts in the casing  1 , and are provided with output gears  19 , respectively.  
         [0053]     Each rod screw  20  is provided rotatably and adjacent to the corresponding one of the drive motors  18  in the casing  1 . Each of the rod screws  20  is provided with a rotation transmission gear  21 , which is engaged with the corresponding output gear  19  of the drive motor  18 . Each of the rod screws  20  is driven to rotate by the corresponding drive motor  18 , and provided with a slider  22 . The slider  22  reciprocates vertically by the rotation of the rod screw  20 .  
         [0054]     The slider  22  is arranged with a pair of engagement claws  22   a  vertically spaced as illustrated in  FIG. 5 . The pair of engagement claws  22   a  preferably has flexibility, and the engagement pin  17   a  of each of the tilting arms  17  is located between the pair of engagement claws  22   a  of the corresponding one of the sliders  22 .  
         [0055]     The engagement pins  17   a  and the pair of shafts  6  are preferably positioned in the same straight line. The laser projector  8  is tilted in the X-direction in the Z-X plane by the engagement of each of the engagement claws  22   a  and each of the engagement pins  17   a.    
         [0056]     Each linear detector  23  is provided and fixed in the casing  1  in such a manner as to face a range of the reciprocal movement of the corresponding one of the sliders  22 . The linear detector  23  is used to optically detect a movement amount from a reference position (or a horizontal position) of the slider  22 . Detection outputs of the sliders  22  outputted from the corresponding linear detectors  23  are inputted to an arithmetic section  24 ; functions of which will be described later.  
         [0057]     Referring to  FIGS. 4 and 6 , a pair of tilting arms  25 , each extending in a direction opposite to each other in the Y-direction, are arranged to the parallel plates  5   a  of the inner frame  5 . Reference numerals  26  denote fixed blocks for fixing and retaining one ends of the tilting arms  25 , respectively. In the present preferred embodiment, the pair of tilting arms  25  structures a part of a Z-Y in-plane tilting mechanism configured to tilt the laser projector  8  in the Y-direction in a Z-Y plane.  
         [0058]     A pair of rod screws  27  is provided rotatably in the casing  1 , and each of the rod screws  27  includes a slider  28  provided vertically moveable. Each of the sliders  28  is arranged with a pair of engagement claws  28   a  which are vertically spaced. Engagement ends  25   a  of the tilting arms  25  are located between the pair of engagement claws  28   a  of the corresponding sliders  28 , respectively. In the present preferred embodiment, drive motors, output gears and rotation transmission gears having the same structures as the drive motors  18 , the output gears  19  and the rotation transmission gears  21  illustrated in  FIG. 5  are used, respectively.  
         [0059]     The laser projector  8  is tilted in the Y-direction in the Z-Y plane by the engagement of each of the engagement claws  28   a  and each of the engagement pins  25 a. Each linear detector  29  is provided and fixed in the casing  1  in such a manner as to face a range of the reciprocal movement of the corresponding one of the sliders  28 . The linear detector  28  is used to optically detect a movement amount from a reference position (or a horizontal position) of the slider  28 . Detection outputs of the sliders  28  outputted from the corresponding linear detectors  29  are inputted to the arithmetic section  24 .  
         [0060]     When the laser projector  8  is to be tilted in the X-direction in the Z-X plane, for example, one of the sliders  22  is raised whereas the other of the sliders  22  is lowered. Accordingly, the movement amount or an amount of raising of one of the sliders  22  from the reference position is detected by the corresponding linear detector  23 , while the movement amount or an amount of lowering of the other slider  22  from the reference position is detected by the corresponding linear detector  23 .  
         [0061]     As illustrated in  FIG. 7 , in the present preferred embodiment, when it is defined that distances from the center of tilt O′ of the laser projector  8  to each of the central axes (or the sliders  22 ) of the rod screws  20  are L 1  and L 2 , respectively, and the movement amounts in the X-axis directions of the sliders  22  of the both ends are ΔX 1  and ΔX 2 , respectively, an angle of inclination θX from a horizontal plane with respect to the X-direction is: 
 
θ X =tan −1 ((Δ X 1+Δ X 2)/( L 1+ L 2)) 
 
         [0062]     Therefore, calculation of the angle of inclination is possible even when there is the play in a supporting mechanism.  
         [0063]     In addition, when the laser projector  8  is to be tilted in the Y-direction in the Z-Y plane, for example, one of the sliders  28  is raised whereas the other of the sliders  28  is lowered. Accordingly, the movement amount or an amount of raising of one of the sliders  28  from the reference position is detected by the corresponding linear detector  29 , while the movement amount or an amount of lowering of the other slider  28  from the reference position is detected by the corresponding linear detector  29 . Then, the arithmetic section  24  obtains an angle of inclination from the horizontal plane with respect to the Y-direction from the detection outputs of the pair of linear detectors  29 .  
         [0064]     Therefore, according to the preferred embodiment of the invention, when the structure in which the laser projector  8  is tilted by utilizing the pairs of the tilting arms is utilized, it is possible to obtain a tilt angle having the angles of inclination of the laser projector  8  precisely, even when the supporting mechanism has the play.  
         [0065]     In addition, when the laser projector  8  is tilted in the X-direction and the Y-direction relative to the horizontal plane at predetermined angles and the rotation cylinder  11  is rotated thereafter, it is possible to form a rotation reference plane or a reference plane having the angles θX and θY relative to the horizontal plane.  
         [0066]     As described in the foregoing, according to the present preferred embodiment, the tilting mechanism is arranged to one of the ends of each of the tilting arms. In an alternative embodiment of the invention, one of the ends of the pair of tilting arms includes only a tilt detecting mechanism configured to detect the movement amount of the slider, and the other of the ends of the pair of tilting arms includes the tilting mechanism. The alternative embodiment of the invention is also possible to set the inclination of the laser projector accurately and precisely.  
         [0067]     The present application is based on and claims priority from Japanese Application Serial Number 2005-309526, filed Oct. 25, 2005, the disclosure of which is hereby incorporated by reference herein in its entirety.  
         [0068]     Although the present invention has been described in terms of exemplary embodiments, it is not limited thereto. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the present invention as defined by the following claims. The limitations in the claims are to be interpreted broadly based the language employed in the claims and not limited to examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. For example, in the present disclosure, the term “preferably”, “preferred” or the like is non-exclusive and means “preferably”, but not limited to. Moreover, no element and component in the present disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.