Patent Publication Number: US-9903573-B2

Title: Lighting equipment

Description:
TECHNICAL FIELD 
     The present invention relates to lighting equipment to be used mainly at an outdoor construction site and for rescue operations, etc. 
     BACKGROUND ART 
     At a construction site, during relief and rescue operations, and firefighting, etc., at night, lighting equipment that illuminates a worksite is essential. The degree of freedom of the light irradiation direction of lighting equipment to be used for these activities is preferably as high as possible. In this regard, the inventors of the present application developed an invention relating to a variable direction type support device described in [Patent Document 1] listed below which can freely change the irradiation direction of illumination upward, downward, rightward, and leftward by installing lighting equipment thereon. In addition, the inventors developed an invention described in [Japanese Patent Application No. 2014-97454] relating to a raising and lowering device with illumination capable of changing the irradiation direction of illumination upward, downward, rightward, and leftward. 
     CITATION LIST 
     Patent Document 
     
         
         [Patent Document 1] Japanese Published Examined Patent Application No. 5433613 
       
    
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     For further improvement in light amount of lighting equipment, use of multi-lamp lighting equipment with multiple illuminating lamps is desirable. The irradiation directions of the illuminating lamps of such multi-lamp lighting equipment are generally set to the same direction to irradiate a number of lights toward a distant object. However, there is a problem that with this lighting equipment, when the light irradiation direction is directed directly downward to illuminate a worksite, only the area directly below the lighting equipment is illuminated, and the worksite cannot be widely illuminated. 
     The present invention was developed in view of the circumstances described above, and an object thereof is to provide lighting equipment with illuminating lamps that automatically turn outward in a state where the lighting equipment is at an elevation angle of −90° at which the light irradiation direction is directed directly downward. 
     Means for Solving the Problem 
     The present invention solves the above-described problem by providing: 
     (1) Lighting equipment  100  including an illuminating portion  90  with four illuminating lamps  20   a ,  20   b ,  20   a ′, and  20   b ′ the elevation angles of which are variable, wherein 
     
         
         
           
             when the illuminating portion  90  is at an elevation angle of −90° at which the illuminating portion  90  is directed directly downward, the illuminating lamps  20   a  to  20   b ′ turn outward at a predetermined elevation angle θ with respect to the direction of the illuminating portion  90 , and the elevation angles of the illuminating lamps  20   a  to  20   b ′ increase or decrease in the range of θ to 0° in inverse proportion to an increase or decrease in elevation angle of the illuminating portion  90  until the elevation angles of the illuminating portion  90  reach a predetermined angle, and when the elevation angle of the illuminating portion  90  is a predetermined angle or more, the elevation angles of the illuminating lamps  20   a  to  20   b ′ are maintained at substantially 0° and the normal direction of the illuminating portion  90  substantially matches the irradiation directions of the illuminating lamps  20   a  to  20   b′.  
 
(2) The lighting equipment  100  according to (1) described above, wherein
 
             the illuminating portion  90  includes 
             a base portion  30  rotatable in the horizontal direction, 
             illuminating arm portions  40  and  40 ′ that are mounted one each on the two side surfaces opposed to each other of the base portion  30 , rotate coaxially right and left, and have both end faces  40   a ,  40   b ,  40   a ′, and  40   b ′ being at approximately 45° to their long-side directions, 
             illuminating lamps  20   a  to  20   b ′ mounted on both end faces  40   a  to  40   b ′ of the illuminating arm portions  40  and  40 ′ so that their elevation angles are variable, 
             link mechanisms  50  provided one each for the illuminating arm portions  40  and  40 ′ and vary the elevation angles of both illuminating lamps  20   a  to  20   b ′ mounted on both end faces  40   a  to  40   b ′ of the illuminating arm portions  40  and  40 ′, wherein 
             the elevation angles of the illuminating lamps  20   a  to  20   b ′ vary by mechanically interlocking with rotations of the illuminating arm portions  40  and  40 ′.
 
(3) The lighting equipment  100  according to (2) described above, wherein
 
             one link mechanism  50  includes 
             a rotary cylinder (first rotary cylinder  84 , second rotary cylinder  84 ′) that rotates the illuminating arm portion  40 ,  40 ′, 
             a fixed shaft  82  coaxial with the rotary cylinder, 
             a fixed link plate  52  that is fixed to the fixed shaft  82  and has an arm  52   a  with a predetermined length, 
             a first link  54  one end of which is connected to the arm  52   a  of the fixed link plate  52 , 
             a three-point plate  60  one point of which is axially supported rotatably on the illuminating arm portion  40 ,  40 ′, to another point of which the other end of the first link  54  is connected, and to the other one point of which a second link  55   a  and a third link  55   b  are connected, 
             a second link  55   a  the other end of which extends toward one end face  40   a ,  40   a ′ of the illuminating arm portion  40 ,  40 ′, 
             a third link  55   b  the other end of which extends toward the other end face  40   b ,  40   b ′ of the illuminating arm portion  40 ,  40 ′, 
             a first link plate  62   a  that is mounted rotatably on the one end face  40   a ,  40   a ′, and connected to the other end of the second link  55   a,    
             a second link plate  62   b  that is mounted rotatably on the other end face  40   b ,  40   b ′, and connected to the other end of the third link  55   b,    
             a first tilt bar  64   a  that rotates together with the first link plate  62   a  and has an arm with a predetermined length, 
             a second tilt bar  64   b  that rotates together with the second link plate  62   b  and has an arm with a predetermined length, 
             a first tilt link  56   a  one end of which is connected to the arm of the first tilt bar  64   a,    
             a second tilt link  56   b  one end of which is connected to the arm of the second tilt bar  64   b,    
             a first tilt stay  66   a  that is fixed to the illuminating lamp  20   a ,  20   a ′ mounted on one end face  40   a ,  40   a ′ of the illuminating arm portion  40 ,  40 ′ and bent into a substantially L-shape the tip end portion of which is connected to the other end of the first tilt link  56   a , and 
             a second tilt stay  66   b  that is fixed to the illuminating lamp  20   b ,  20   b ′ mounted on the other end face  40   b ,  40   b ′ of the illuminating arm portion  40 ,  40 ′ and bent into a substantially L-shape the tip end portion of which is connected to the other end of the second tilt link  56   b , wherein 
             according to rotations of the illuminating arm portions  40  and  40 ′, the three-point plates  60  rotate, the second links  55   a  and the third links  55   b  connected to the three-point plates  60  move in substantially the same direction, the first link plates  62   a  and the second link plates  62   b  rotate respectively and push and pull the tip sides bent into substantially L-shapes of the first tilt stays  66   a  and the second tilt stays  66   b  to vary the elevation angles of the illuminating lamps  20   a  to  20   b ′ on both end faces  40   a  to  40   b ′ by equal amounts, respectively.
 
(4) The lighting equipment  100  according to (3) described above, wherein
 
             a vertical fixed shaft  14  coaxial with the rotation axis in the horizontal direction of the base portion  30  and the fixed shaft  82  of the illuminating arm portions  40  and  40 ′ are joined in a T-shape, and 
             the rotary shaft portion  80  of the illuminating arm portions  40  and  40 ′ includes a first rotary cylinder  84  that is connected to one illuminating arm portion  40  and inserted on the fixed shaft  82 , a second rotary cylinder  84 ′ that is connected to the other illuminating arm portion  40 ′ and inserted on the fixed shaft  82 , and a connecting bar  86  that joins the first rotary cylinder  84  and the second rotary cylinder  84 ′, where 
             the connecting bar  86  is fixed to circumferential surfaces of portions of the first rotary cylinder  84  and the second rotary cylinder  84 ′, and 
             further includes 
             a tilt limiting means that limits the rotation ranges of the first rotary cylinder  84  and the second rotary cylinder  84 ′ to prevent the connecting bar  86  from coming into contact with the vertical fixed shaft  14 . 
           
         
       
    
     Effect of the Invention 
     Lighting equipment according to the present invention has illuminating lamps that automatically turn outward when the lighting equipment is at a directly downward illuminating position with an elevation angle of −90° at which the light irradiation direction is directed directly downward. Therefore, a worksite can be widely illuminated without special operations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of lighting equipment according to the present invention. 
         FIG. 2  is a perspective view of the lighting equipment according to the present invention when it is at a directly downward illuminating position. 
         FIGS. 3( a ) and 3( b )  are schematic views showing the interior of the base portion of the lighting equipment according to the present invention. 
         FIG. 4  is a schematic configuration diagram of a link mechanism viewed from immediately below of the lighting equipment according to the present invention when it is at the directly downward illuminating position. 
         FIG. 5  is a schematic configuration diagram of the link mechanism of the lighting equipment according to the present invention when it is at the directly downward illuminating position. 
         FIG. 6  is a schematic configuration diagram of the link mechanism of the lighting equipment according to the present invention when the lighting equipment is at an elevation angle of −45°. 
         FIG. 7  is a schematic configuration diagram of the link mechanism of the lighting equipment according to the present invention when the lighting equipment is at an elevation angle of 0°. 
         FIGS. 8( a ) and 8( b )  are partial enlarged views of the link mechanism of the lighting equipment according to the present invention. 
         FIG. 9  shows illuminance distribution simulation results of the lighting equipment according to the present invention. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     An embodiment of lighting equipment  100  according to the present invention is described based on the drawings. Here,  FIG. 1  is a front view of the lighting equipment  100  according to the present invention when an illuminating portion  90  is at an elevation angle of 0° (directed toward the horizontal direction).  FIG. 2  is a perspective view when the illuminating portion  90  of the lighting equipment  100  according to the present invention is at an elevation angle of −90° (directly downward illuminating position at which the illuminating portion  90  is directed directly downward). The lighting equipment  100  according to the present invention is assumed to be installed on a special-purpose vehicle such as a fire truck and work by obtaining power from the vehicle. However, the vehicle on which the lighting equipment is installed is not limited to this, and the lighting equipment may be installed on a construction vehicle or other vehicles. In addition, the lighting equipment may also be mounted on a cart or base, etc., and used. 
     First, the lighting equipment  100  according to the present invention includes an illuminating portion  90  and a post portion  10 . The illuminating portion  90  includes a base portion  30  connected to the post portion  10 , illuminating arm portions  40  and  40 ′ mounted one each on the two side surfaces opposed to each other of the base portion  30 , illuminating lamps  20   a ,  20   b ,  20   a ′, and  20   b ′ mounted on the respective end faces  40   a ,  40   b ,  40   a ′ and  40   b ′ of the illuminating arm portions  40  and  40 ′ so that their elevation angles are variable, and link mechanisms  50  that are provided one each for the illuminating arm portions  40  and  40 ′ to vary the elevation angles of the illuminating lamps  20   a  to  20   b ′. The link mechanisms  50  are described in detail later. The end faces  40   a  to  40   b ′ of the illuminating arm portions  40  and  40 ′ are at angles of substantially 45° to the long-side directions of the illuminating arm portions  40  and  40 ′, and the illuminating lamps  20   a  to  20   b ′ are mounted via illuminating lamp stays  22  fixed to the end faces  40   a  to  40   b ′, respectively. Further, the lighting equipment  100  includes a rotation mechanism  12  that rotates the illuminating portion  90  in the horizontal direction (direction horizontal with respect to the post portion  10 ). In this example, the rotation mechanism  12  is provided at the connecting portion between the post portion  10  and the base portion  30 , however, the configuration of the rotation mechanism  12  is not especially limited to this. 
     The post portion  10  holds the illuminating portion  90  at a predetermined height, a post portion that is manually or electrically raised and lowered is preferably used, and it is particularly preferable that the post portion  10  is formed into a pipe and cables to be connected to the respective portions of the illuminating portion  90  are inserted inside the pipe and connected to an operation panel and a power supply located below. 
     The four illuminating lamps  20   a ,  20   b ,  20   a ′, and  20   b ′ are preferably disposed radially at even intervals, and therefore, right and left illuminating arm portions  40  and  40 ′ are formed so that the illuminating lamps  20   a  to  20   b ′ are positioned symmetrically to each other with respect to both of the axis shown by the alternate long and short dash line and the axis shown by the alternate long and short two dashes line in  FIG. 1 . 
     Next, an example of the preferable rotation mechanism  12  of the lighting equipment  100  is described with reference to  FIG. 3( a ) .  FIG. 3( a )  is a schematic view showing the interior of the base portion  30 . The rotation mechanism  12  preferable for the lighting equipment  100  shown in  FIG. 3( a )  includes a horizontal rotary gear  16  fixed to the bottom surface of the base portion  30 , and a horizontal rotary motor  18  connected to the horizontal rotary gear  16 . When a user performs an operation to pan the lighting equipment  100  by using the operation panel, etc., the horizontal rotary motor  18  rotates, and according to this, the horizontal rotary gear  16  rotates and the base portion  30  rotates together with the illuminating arm portions  40  and  40 ′. Accordingly, the illuminating portion  90  rotates in the horizontal direction, and the lighting equipment  100  pans. The rotation mechanism  12  may be provided with a horizontal direction detection means that detects the irradiation direction of the illuminating portion  90  (direction of the base portion  30 ). With this configuration, according to signals from the horizontal direction detection means, the rotation range of the illuminating portion  90  can be limited and the illuminating portion  90  can be automatically positioned in a specific direction set in advance. Here, a preferable example of the horizontal direction detection means is shown. A preferable horizontal direction detection means of the lighting equipment  100  according to the present invention includes a fixed cylinder  15  that is fixed to the post portion  10  side and has a mark such as a concavity or convexity marked at a predetermined position on the circumferential surface, and a pan sensor  19  that comes into sliding contact with the circumferential surface of the fixed cylinder  15 . When the base portion  30  is rotated by the horizontal rotary motor  18 , the pan sensor  19  rotates and moves along the circumferential surface of the fixed cylinder  15  and detects the mark on the circumferential surface of the fixed cylinder  15 . Then, according to a signal from this pan sensor  19 , the direction of the illuminating portion  90  is recognized, and predetermined pan control is performed for the illuminating portion  90 . 
     Next, a preferable example of the rotary shaft portion  80  that rotates the illuminating arm portions  40  and  40 ′ is described. First, in the base portion  30 , a fixed shaft  82  that penetrates two side surfaces opposed to each other is provided. On this fixed shaft  82 , a first rotary cylinder  84  connected to one illuminating arm portion  40  and a second rotary cylinder  84 ′ connected to the other illuminating arm portion  40 ′ are inserted movably. Circumferential surfaces of portions of the first rotary cylinder  84  and the second rotary cylinder  84 ′ are fixed by a connecting bar  86 , and by this connecting bar  86 , the first rotary cylinder  84  and the second rotary cylinder  84 ′ are joined. The fixed shaft  82  is partially exposed between the first rotary cylinder  84  and the second rotary cylinder  84 ′. The rotary shaft portion  80  is provided with a vertical fixed shaft  14  coaxial with the horizontal rotary gear  16 , that is, coaxial with the rotation axis in the horizontal direction of the base portion  30 , and this vertical fixed shaft  14  and the fixed shaft  82  are joined in a T-shape at the exposed portion between the first rotary cylinder  84  and the second rotary cylinder  84 ′. Thus, by joining the vertical fixed shaft  14  in the vertical direction and the fixed shaft  82  in the horizontal direction in a T-shape, torsion and eccentricity are suppressed at the time of pivoting of the illuminating arm portions  40  and  40 ′ and panning of the illuminating portion  90 , and rotating operations of the respective portions of the illuminating portion  90  can be smoothly performed. 
     For each of the first rotary cylinder  84  and the second rotary cylinder  84 ′, a rotary gear  85  is formed, and to this rotary gear  85 , a tilt motor (not shown) is connected. When tilt motors rotate, the rotary gears  85  rotate, and accordingly, the first rotary cylinder  84  and the second rotary cylinder  84 ′ rotate and the illuminating arm portions  40  and  40 ′ pivot with the same phase in the same direction. At this time, the fixed shaft  82  inserted in the first rotary cylinder  84  and the second rotary cylinder  84 ′ does not rotate. 
     In the case where the vertical fixed shaft  14  and the fixed shaft  82  are joined in a T-shape, there is a possibility that the connecting bar  86  collides with the vertical fixed shaft  14  due to rotations of the first rotary cylinder  84  and the second rotary cylinder  84 ′. Therefore, it is preferable that the first rotary cylinder  84  or the second rotary cylinder  84 ′ is provided with a tilt limiting means that limits the rotation ranges of the first rotary cylinder  84  and the second rotary cylinder  84 ′. This tilt limiting means has, for example, as shown in  FIG. 3( b ) , a configuration in which a mark such as a step, a concavity or convexity, etc., is provided at a predetermined position on the circumferential surface of the first rotary cylinder  84  or the second rotary cylinder  84 ′, a detecting member  88  that detects this mark is provided, and the rotation ranges of the first rotary cylinder  84  and the second rotary cylinder  84 ′ are limited according to a signal from this detecting member  88 . 
     Next, the configuration and operation of the link mechanism  50  of the lighting equipment  100  is described with reference to  FIG. 4  to  FIG. 8 . Here,  FIG. 4  is a schematic configuration diagram of the link mechanism  50  of one illuminating arm portion  40  viewed from immediately below when it is at the directly downward illuminating position.  FIG. 5  is a schematic configuration diagram of the link mechanism  50  viewed from the base portion  30  side when it is at the directly downward illuminating position.  FIG. 6  is a schematic configuration diagram of the link mechanism  50  viewed from the base portion  30  side when the illuminating portion  90  is at an elevation angle of −45°.  FIG. 7  is a schematic configuration diagram of the link mechanism  50  viewed from the base portion  30  side when the illuminating portion  90  is at an elevation angle of 0° (directed toward the horizontal direction).  FIG. 8  are partial enlarged views of the link mechanisms  50  shown in  FIG. 5  and  FIG. 6 . The link mechanism  50  of the illuminating arm portion  40  and the link mechanism  50  of the illuminating arm portion  40 ′ are configured symmetrically to each other, and their operations are the same. Here, the configuration and operation of one illuminating arm portion  40  is described. 
     First, as shown in  FIG. 4 , to one illuminating arm portion  40 , the first rotary cylinder  84  that rotates around the fixed shaft  82  is fixed. According to rotation of the first rotary cylinder  84 , the illuminating arm portion  40  pivots around the fixed shaft  82 . The fixed shaft  82  is inserted in the illuminating arm portion  40 , and as shown in  FIG. 4  to  FIG. 7 , fixed to a fixed link plate  52  having an arm  52   a  with a predetermined length. Therefore, the direction of the fixed link plate  52  and the arm  52   a  is always constant and does not change regardless of pivoting of the illuminating arm portion  40 . To the arm  52   a  of the fixed link plate  52 , one end of a first link  54  with a predetermined length is connected movably. Both ends of the first link  54  and a second link  55   a , a third link  55   b , a first tilt link  56   a , and a second tilt link  56   b  which are described later are connected respectively by, for example, ball joints, etc., that can move three-dimensionally. Further, the link mechanism  50  has a three-point plate  60  one point of which is axially supported on the illuminating arm portion  40  by a shaft pin  60   a . To another point of the three-point plate  60 , the other end of the first link  54  is connected. To the other one point of the three-point plate  60 , one end of the second link  55   a  extending toward one end face  40   a  and one end of the third link  55   b  extending toward the other end face  40   b  are connected. To avoid contact between the second link  55   a  and the third link  55   b , it is preferable that, as shown in  FIG. 4 , they are connected to the front surface side and back surface side of the three-point plate  60 , respectively, and bent at a predetermined angle to excellently transmit the rotation of the three-point plate  60  to the first link plate  62   a  and the second link plate  62   b.    
     The other end of the second link  55   a  is connected to the arm of the first link plate  62   a  mounted rotatably on one end face  40   a  of the illuminating arm portion  40 . The other end of the third link  55   b  is connected to the arm of the second link plate  62   b  mounted rotatably on the other end face  40   b  of the illuminating arm portion  40 . To the first link plate  62   a , the first tilt bar  64   a  that rotates together with the first link plate  62   a  and has an arm with a predetermined length is fixed. To the second link plate  62   b , the second tilt bar  64   b  that rotates together with the second link plate  62   b  and has an arm with a predetermined length is fixed. To the bottom surface of the illuminating lamp  20   a , the first tilt stay  66   a  the front surface side of which is bent into a substantially L-shape toward the base portion  30  side is fixed, and the tip side of the bent first tilt stay  66   a  and the tip side of the arm of the first tilt bar  64   a  are joined by the first tilt link  56   a . To the bottom surface of the illuminating lamp  20   b , the second tilt stay  66   b  the front surface side of which is bent into a substantially L-shape toward the base portion  30  side is fixed, and the tip side of the bent second tilt stay  66   b  and the tip side of the arm of the second tilt bar  64   b  are joined by the second tilt link  56   b.    
     Lengths and angles, etc., of these components of the link mechanisms  50  are appropriately designed to optimum values according to the dimensions of the respective portions constituting the illuminating portion  90  and the value of the elevation angle θ required for the illuminating lamps  20   a  to  20   b ′, etc. However, the first tilt bar  64   a , the first tilt link  56   a , and the first tilt stay  66   a , and the second tilt bar  64   b , the second tilt link  56   b , and the second tilt stay  66   b  are configured so as to become axisymmetric to each other with respect to the axis of the fixed shaft  82 . On the other hand, the angle between the first link plate  62   a  and the first tilt bar  64   a  and the angle between the second link plate  62   b  and the second tilt bar  64   b  are individually set to appropriate angles. The phase difference between the first link plate  62   a  and the second link plate  62   b  is approximately 120°, and when the second link  55   a  and the third link  55   b  are moved by the three-point plate  60 , the first link plate  62   a  and the second link plate  62   b  connected to these links rotate in directions opposite to each other. 
     Next, operation of the link mechanism  50  is described. First, when the illuminating portion is at the directly downward illuminating position shown in  FIG. 5 , the tip ends of the arms of the first tilt bar  64   a  and the second tilt bar  64   b  are positioned in the very front side. Accordingly, the tip sides of the first tilt stay  66   a  and the second tilt stay  66   b  bent into L-shapes are pressed forward via the first tilt link  56   a  and the second tilt link  56   b , and the illuminating lamps  20   a  and  20   b  turn outward around the holding shafts of the illuminating lamp stays  22 . At this time, the elevation angle θ of the illuminating lamps  20   a  and  20   b  with respect to the direction of the illuminating portion  90  is preferably 20° to 40°, and most preferably 30°. 
     Next, when the elevation angle of the illuminating portion  90  is increased from the state at the directly downward illuminating position shown in  FIG. 5  to the state shown in  FIG. 6  or  FIG. 7 , a user performs a tilting operation by using the operation panel, etc. Accordingly, the tilt motors inside the base portion  30  rotate, and via the rotary gears  85 , the first rotary cylinder  84  and the second rotary cylinder  84 ′ rotate. When the first rotary cylinder  84  rotates, the illuminating arm portions  40  and  40 ′ fixed to the first rotary cylinder  84  and the second rotary cylinder  84 ′ pivot in a direction to increase the elevation angle of the illuminating portion  90  (counterclockwise in  FIG. 5  to  FIG. 7 ) around the fixed shaft  82 . At this time, the fixed link plates  52  fixed to the fixed shaft  82  do not change regardless of the rotating operation of the illuminating arm portions  40  and  40 ′ as shown in  FIG. 8( a )  and  FIG. 8( b ) . However, the three-point plates  60  mounted on the illuminating arm portions  40  and  40 ′ revolve around the fixed shaft  82  according to rotation of the illuminating arm portions  40  and  40 ′ as shown by the solid arrow in  FIG. 8( a ) . At this time, the rotation of the three-point plate  60  is limited by the first link  54  connected to the fixed link plate  52 , and as a result, the three-point plate  60  spins in the direction shown by the dashed-line arrow in  FIG. 8( a )  around the shaft pin  60   a  while revolving around the fixed shaft  82 . When the illuminating portion is at a position near the directly downward illuminating position, the arm  52   a  of the fixed link plate  52  is in a direction substantially perpendicular to the lines between the shaft pin  60   a  and the fixed shaft  82 , and in this region, the displacement amounts of the arm  52   a  and the three-point plate  60  are comparatively large. According to turning of the three-point plate  60 , both of the second link  55   a  and the third link  55   b  connected to the other one point of the three-point plate  60  move to the illuminating lamp  20   a  side as shown by the arrows in  FIG. 8( b ) . Then, according to this movement of the second link  55   a , the first link plate  62   a  is pressed and rotates counterclockwise in  FIG. 5 . Accordingly, the first tilt bar  64   a  fixed to the first link plate  62   a  also rotates counterclockwise, and the arm of the first tilt bar  64   a  moves to the back surface side of the illuminating portion  90 . Accordingly, the tip side of the first tilt stay  66   a  is pulled via the first tilt link  56   a  and the elevation angle of the illuminating lamp  20   a  decreases from the angle θ. According to movement of the third link  55   b , the second link plate  62   b  is pulled and rotates clockwise in  FIG. 5 . Accordingly, the second tilt bar  64   b  fixed to the second link plate  62   b  also rotates clockwise, and the arm of the second tilt bar  64   b  moves to the back surface side of the illuminating portion  90 . Accordingly, the tip side of the second tilt stay  66   b  is pulled via the second tilt link  56   b  and the elevation angle of the illuminating lamp  20   b  decreases from the angle θ. At this time, the variation in elevation angle of the illuminating lamp  20   b  is equal to that of the illuminating lamp  20   a . The illuminating arm portion  40 ′ also performs the above-described operation in the exact same manner, and accordingly, the elevation angles of the four illuminating lamps  20   a ,  20   b ,  20   a ′, and  20   b ′ of the illuminating portion  90  decrease in inverse proportion to an increase in elevation angle of the illuminating portion  90  (illuminating arm portions  40  and  40 ′). 
     Then, when the illuminating portion  90  reaches a predetermined elevation angle, the elevation angles of the illuminating lamps  20   a  to  20   b ′ become 0°, and the normal direction of the illuminating portion  90  substantially matches the irradiation directions of the illuminating lamps  20   a  to  20   b ′. It is preferable that the variation in elevation angle of the illuminating portion  90  (illuminating arm portions  40  and  40 ′) and the variation in elevation angle of the illuminating lamps  20   a  to  20   b ′ are set to be equal to each other. That is, they are preferably configured so that, in the case where the elevation angles θ of the illuminating lamps  20   a  to  20   b ′ at the directly downward illuminating position are 30°, the elevation angles of the illuminating lamps  20   a  to  20   b ′ become 0° when the illuminating arm portions  40  and  40 ′ pivot 30°. 
     Then, when the elevation angle of the illuminating portion  90  is further increased from the state shown in, for example,  FIG. 6  where the elevation angles of the illuminating lamps  20   a  to  20   b ′ are 0°, the illuminating arm portions  40  and  40 ′ are caused to further pivot by the tilt motors. However, in this region, the arms  52   a  of the fixed link plates  52  are positioned at the sides opposite to the shaft pins  60   a  across the fixed shaft  82 , and the displacement amounts of the three-point plates  60  with respect to pivoting of the illuminating arm portions  40  and  40 ′ are small. Therefore, the second links  55   a  and the third links  55   b  move little, and the elevation angles of the illuminating lamps  20   a  to  20   b ′ are maintained at nearly 0°. The range of variation of the elevation angle of the illuminating portion  90  is, for example, from the directly downward illuminating position (−90°) to approximately 130°, and a change in elevation angle beyond this range is limited by the above-described tilt limiting means. 
     When the elevation angle of the illuminating portion  90  is decreased from this state, the elevation angles of the illuminating lamps  20   a  to  20   b ′ are maintained at nearly 0° until the elevation angle of the illuminating portion  90  reaches a predetermined angle. Then, when the elevation angle of the illuminating portion  90  decreases from the predetermined angle, the amount of displacement of the three-point plate  60  increases, and the second link  55   a  and the third link  55   b  connected to the three-point plate  60  moves to the illuminating lamp  20   b  side. Due to this movement of the second link  55   a , the first link plate  62   a  is pulled and rotates clockwise in  FIG. 6 . Accordingly, the first tilt bar  64   a  also rotates clockwise, and the arm of the first tilt bar  64   a  moves to the irradiating surface side of the illuminating portion  90 . Accordingly, the tip side of the first tilt stay  66   a  is pressed via the first tilt link  56   a , and the elevation angle of the illuminating lamp  20   a  increases from 0°. In addition, due to the movement of the third link  55   b , the second link plate  62   b  is pressed and rotates counterclockwise in  FIG. 6 . Accordingly, the second tilt bar  64   b  also rotates counterclockwise, and the arm of the second tilt bar  64   b  moves to the irradiating surface side of the illuminating portion  90 . Accordingly, the tip side of the second tilt stay  66   b  is pressed via the second tilt link  56   b , and the elevation angle of the illuminating lamp  20   b  increases from 0°. The illuminating arm portion  40 ′ on the opposite side also performs the above-described operation in the exact same manner, and therefore, the elevation angles of the four illuminating lamps  20   a ,  20   b ,  20   a ′, and  20   b ′ of the illuminating portion  90  increase in inverse proportion to a decrease in elevation angle of the illuminating portion  90  (illuminating arm portions  40  and  40 ′). Then, the illuminating arm portions  40  and  40 ′ are stopped by the tilt limiting means when reaching the directly downward illuminating position shown in  FIG. 5 . At this time, the illuminating lamps  20   a  to  20   b ′ turn outward at an elevation angle θ with respect to the direction of the illuminating portion  90  and illuminate the surrounding of the illuminating portion  90 . 
     Each of the illuminating lamps  20   a ,  20   b ,  20   a ′, and  20   b ′ preferably includes, as shown in  FIG. 1 , an illuminating means  26  that illuminates the orthogonal direction, and a long lamp  24  the light of which is distributed in the lateral direction. With this configuration, as shown in the illuminance distribution simulation results in  FIG. 9 , the illuminating light from the illuminating portion  90  is distributed in a cross direction so that the central portion is superimposed, and the illuminance of the central portion can be increased at the time of distant irradiation. From the viewpoint of energy-saving, high-illuminance LEDs are preferably used as the illuminating means  26  and the long lamp  24 . 
     As described above, in the lighting equipment  100  according to the present invention, when the illuminating portion  90  is at the directly downward illuminating position with an elevation angle of −90°, the illuminating lamps  20   a ,  20   b ,  20   a ′, and  20   b ′ automatically turn outward. Accordingly, a worksite can be widely illuminated. In the region in which the elevation angle of the illuminating portion  90  is a predetermined angle or more, the elevation angles of the illuminating lamps  20   a  to  20   b ′ are maintained at substantially 0° and the normal direction of the illuminating portion  90  substantially matches the irradiation directions of the illuminating lamps  20   a  to  20   b ′. Accordingly, the illuminating portion  90  can illuminate a distant object with a high illuminance. The elevation angles of the illuminating lamps  20   a  to  20   b ′ are varied and maintained by the link mechanisms  50  that vary the elevation angles of the illuminating lamps  20   a  to  20   b ′ according to rotations of the illuminating arm portions  40  and  40 ′, by mechanically interlocking with pivoting of the illuminating arm portions  40  and  40 ′. Accordingly, it becomes possible that the elevation angles of the illuminating lamps  20   a  to  20   b ′ are varied by only the tilt motors that cause the illuminating arm portions  40  and  40 ′ to pivot, and therefore, reduction in component cost and high operation stability are realized. 
     The shapes, dimensions, and configurations, etc., of the lighting equipment  100 , the illuminating portion  90 , the link mechanisms  50 , and other components shown in this example are just examples, and the present invention can be modified and carried out without departing from the scope of the present invention. 
     REFERENCE SIGNS LIST 
     
         
           14  Vertical fixed shaft 
           20   a ,  20   b ,  20   a ′,  20   b ′ Illuminating lamp 
           30  Base portion 
           40 ,  40 ′ Illuminating arm portion 
           40   a ,  40   a ′ One end face 
           40   b ,  40   b ′ Other end face 
           50  Link mechanism 
           52  Fixed link plate 
           52   a  Arm (of fixed link plate) 
           54  First link 
           55   a  Second link 
           55   b  Third link 
           56   a  First tilt link 
           56   b  Second tilt link 
           60  Three-point plate 
           62   a  First link plate 
           62   b  Second link plate 
           64   a  First tilt bar 
           64   b  Second tilt bar 
           66   a  First tilt stay 
           66   b  Second tilt stay 
           80  Rotary shaft portion 
           84  First rotary cylinder 
           84 ′ Second rotary cylinder 
           86  Connecting bar 
           82  Fixed shaft 
           90  Illuminating portion 
           100  Lighting equipment