Dot point glazing apparatus
BACKGROUND OF THE INVENTION 
     The present invention relates to a dot point glazing apparatus for assembling glass plates into a glass screen. 
     Various types of glazing systems, such as the curtain wall system, the structural sealant glazing system, the dot point glazing system, etc., are used for assembling glass plates into a glass screen. 
     In the dot point glazing system, a dot point glazing apparatus engages holes made in the glass plates to support them. 
     The glazing apparatus 400 shown in FIG. 17 is one of the most effective dot point glazing apparatuses used in the dot point glazing system. As shown in FIG. 17, the dot point glazing apparatus 400 has a longitudinally extending rod 401 and a transversely extending straight arm 402 which engages the front end of the rod 401 at its center to be rotatable around the rod 401. A vertically extending straight arm 403a engages the right end of the straight arm 402 at its center to be rotatable around a longitudinally extending axis. A vertically extending straight arm 403b engages the left end of the straight arm 402 at its center to be rotatable around a longitudinally extending axis. 
     A longitudinally extending bolt 404a 1  penetrates a hole made at the left lower corner of a glass plate 405a 1  and a washer 406a 1 , and is screwed into a tapped hole made at upper end of the straight arm 403a. Thus, the glass plate 405a 1  is connected to the dot point glazing apparatus 400 at its left lower corner. In the same way, a glass plate 405a 2  disposed adjacent to and below the glass plate 405a 1  is connected to the dot point glazing apparatus 400 at its left upper corner, a glass plate 405b 1  disposed adjacent to and left of the glass plate 405a 1  is connected to the dot point glazing apparatus 400 at its right lower corner, and a plate 405b 2  disposed adjacent to and below the glass plate 405b 1  is connected to the dot point glazing apparatus 400 at its right upper corner. 
     The glass plates 405a 1 , 405a 2 , 405b 1  and 405b 2  are connected to other similar dot point glazing apparatuses 400 (not shown) disposed at the other corners of the glass plates 405a 1 , 405a 2 , 405b 1  and 405b 2 . 
     The rods 401 are connected to structural members which are disposed to the rear of the dot point glazing apparatuses 400 at their rear ends. 
     A glass screen module is formed by the glass plates 405a 1 , 405a 2 , 405b 1  and 405b 2 . A plurality of the glass screen modules may be assembled in the vertical direction and in the transverse direction to form a glass screen. 
     The glazing apparatuses 400 bear the weights of the glass plates 405a 1 , 405a 2 , 405b 1  and 405b 2 , and the wind loads acting on the glass plates 405 1 , 405a 2 , 405b 1  and 405b 2 . 
     In-plane vertical relative displacements between the glass plates 405a 1  and 405b 1 , and between the glass plates 405a 2  and 405b 2  are allowed by the rotation of the transverse straight arm 402, while in-plane horizontal relative displacements between the glass plates 405a 1  and 405a 2 , and between the glass plates 405b 1  and 405b 2  are allowed by the rotation of the right vertical straight arm 403a, and the left vertical straight arm 403b respectively. 
     Thus, shear deformation of the glass screen module is allowed when an earthquake occurs, which protects the glass screen module from damage. 
     As will be understood from the above explanation, the dot point glazing apparatus 400 shown in FIG. 17 can effectively protect the glass screen module from damage when an earthquake occurs. 
     Though the dot point glazing apparatus 400 has the above merit, it has also a demerit. Once the transverse straight arm 402 has rotated, it does not readily restore to the original state. As a result, the in-plane vertical relative displacements between the glass plates 405a 1  and 405b 1 , and between the glass plates 405a 2  and 405b 2 , do not readily disappear after the earthquake stops. Because of this, the shear deformation of the glass screen module does not readily disappear after the earthquake stops. In order to overcome the above demerit, the upper most glass plates in the glass screen module, i.e. the glass plates 405a 1 , 405b 1  must be suspended by spring members at the centers of their upper peripheries. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a dot point glazing apparatus for assembling glass plates into a glass screen which can effectively protect the glass screen from damage when an earthquake occurs and readily restore the shear deformed glass screen to the original state after the earthquake stops. 
     In accordance with the present invention, there is provided a dot point glazing apparatus comprising a rod, a straight arm which engages one end of the rod at its center to be rotatable around the rod, a first V-shaped arm which engages one end of the straight arm at its center to be rotatable around an axis extending parallel to the rod, a second V-shaped arm which engages the other end of the straight arm at its center to be rotatable around an axis extending parallel to the rod, and four bolts which threadedly engage the ends of the V-shaped arms. 
     In accordance with a preferred embodiment of the present invention, there is provided a dot point glazing apparatus comprising a rod, a straight arm which engages one end of the rod at its center to be rotatable around the rod, a V-shaped arm which engages one end of the straight arm at its center to be rotatable around an axis extending parallel to the rod, two bolts which threadedly engage the ends of the V-shaped arm. 
     In accordance with another preferred embodiment of the present invention, there is provided a dot point glazing apparatus comprising a rod, a first straight arm which engages one end of the rod at its center to be rotatable around the rod, a second straight arm which engages one end of the first straight arm at its one end to be rotatable around an axis extending parallel to the rod, a third straight arm which engages the other end of the first straight arm at its one end to be rotatable around an axis extending parallel to the rod, and two bolts which threadedly engage the other ends of the second and the third straight arms. 
     In accordance with another preferred embodiment of the present invention, there is provided a dot point glazing apparatus comprising a rod, a first straight arm which engages one end of the rod at its center to be rotatable around the rod, a second straight arm which engages one end of the first straight arm at its one end to be rotatable around an axis extending parallel to the rod, and a bolt which threadedly engages the other end of the second arm. 
     In accordance with another aspect of the present invention, there is provided a dot point glazing system which comprises: 
     (a) a plurality of first dot point glazing apparatuses each of which has a rod, a straight arm which engages one end of the rod at its center to be rotatable around the rod, a first V-shaped arm which engages one end of the straight arm at its center to be rotatable around an axis extending parallel to the rod, a second V-shaped arm which engages the other end of the straight arm at its center to be rotatable around an axis extending parallel to the rod, and four bolts which threadedly engage the ends of the V-shaped arms; 
     (b) a plurality of second dot point glazing apparatuses each of which has a rod, a straight arm which engages one end of the rod at its center to be rotatable around the rod, a V-shaped arm which engages one end of the straight arm at its center to be rotatable around an axis extending parallel to the rod, and two bolts which threadedly engage the ends of the V-shaped arm; 
     (c) a plurality of third dot point glazing apparatuses each of which has a rod, a first straight arm which engages one end of the rod at its center to be rotatable around the rod, a second straight arm which engages one end of the first straight arm at its one end to be rotatable around an axis extending parallel to the rod, a third straight arm which engages the other end of the first straight arm at its one end to be rotatable around an axis extending parallel to the rod, and two bolts which threadedly engage the other ends of the second and the third straight arms; 
     (d) a plurality of fourth dot point glazing apparatuses each of which has a rod, a first straight arm which engages one end of the rod at its center to be rotatable around the rod, a second straight arm which engages one end of the first straight arm at its one end to be rotatable around an axis extending parallel to the rod, and a bolt which threadedly engages the other end of the second arm; and 
     (e) rods which connect the first, the second, the third, and the fourth dot point glazing apparatuses to structural members. 
     Further objects, features and advantages of the present invention will become apparent from the Detailed Description of the Preferred Embodiments when read in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a side view showing a dot point glazing apparatus in accordance with a preferred embodiment of the present invention. 
     FIG. 2 is a front view of the dot point glazing apparatus of FIG. 1 as viewed in the direction of the arrow A. 
     FIG. 3 is a perspective view of the dot point glazing apparatus of FIG. 1. 
     FIG. 4 is a side view showing a dot point glazing apparatus in accordance with another embodiment of the present invention. 
     FIG. 5 is a front view of the dot point glazing apparatus of FIG. 4 as viewed in the direction of the arrow B. 
     FIG. 6 is a side view showing a dot point glazing apparatus in accordance with another embodiment of the present invention. 
     FIG. 7 is a front view of the dot point glazing apparatus of FIG. 6 as viewed in the direction of the arrow C. 
     FIG. 8 is a side view showing a dot point glazing apparatus in accordance with another preferred embodiment of the present invention. 
     FIG. 9 is a front view of the dot point glazing apparatus of FIG. 8 as viewed in the direction of the arrow D. 
     FIG. 10 is a perspective view of the dot point glazing apparatus of FIG. 8. 
     FIG. 11 is a side view showing a dot point glazing apparatus in accordance with another embodiment of the present invention. 
     FIG. 12 is a front view of the dot point glazing apparatus of FIG. 11 as viewed in the direction of the arrow E. 
     FIG. 13 is a side view showing a dot point glazing apparatus in accordance with another embodiment of the present invention. 
     FIG. 14 is a front view of the dot point glazing apparatus of FIG. 13 as viewed in the direction of the arrow F. 
     FIG. 15 is a plan view of a glass screen constituted by the dot point glazing apparatuses in accordance with the embodiments of the present invention and glass plates which are connected to the dot point glazing apparatuses at their corners. 
     FIG. 16 is a front view of the glass screen of FIG. 15 as view in the direction of the arrow G. 
     FIG. 17 is a perspective view of the conventional dot point glazing apparatus. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in FIG. 16, a plurality of glass plates 1 are disposed adjacent to each other in the transverse direction and in the vertical direction to define a glass screen 2. 
     In the top row of the glass plates, the glass plates 1 are connected to dot point glazing apparatuses 30 at their right and left upper corners and to dot point glazing apparatuses 10 at their right and left lower corners, except for the rightmost and the leftmost glass plates 1. The rightmost glass plate 1 is connected to a dot point glazing apparatus 60 at its right upper corner and to a dot point glazing apparatus 50 at its right lower corner. The leftmost glass plate 1 is connected to the dot point glazing apparatus 60 at its left upper corner and to the dot point glazing apparatus 50 at its left lower corner. 
     In the middle row of the glass plates, the glass plates 1 are connected to the dot point glazing apparatuses 10 at their four corners, except for the rightmost and the leftmost glass plates 1. The rightmost glass plate 1 is connected to the dot point glazing apparatuses 50 at its right upper and right lower corners. The leftmost glass plate 1 is connected to the dot point glazing apparatuses 50 at its left upper and left lower corners. 
     In the bottom row of the glass plates, the glass plates 1 are connected to the dot point glazing apparatuses 10 at their right and left upper corners and to the dot point glazing apparatuses 40 at their right and left lower corners, except for the rightmost and the leftmost glass plates 1. The rightmost glass plate 1 is connected to the dot point glazing apparatus 50 at its right upper corner and to a dot point glazing apparatus 70 at its right lower corner. The leftmost glass plate 1 is connected to the dot point glazing apparatus 50 at its left upper corner and to the dot point glazing apparatus 70 at its left lower corner. 
     The dot point glazing apparatuses 10, 30, 20, 50, 60 and 70 will be described in detail, with particular attention being paid to glass plates 1a 1 , 1a 2 , 1a 3  in the rightmost column of the glass plates and the glass plates 1b 1 , 1b 2 , 1b 3  in the column of the glass plates next to the rightmost column. 
     Dot point glazing apparatus 10 
     As shown in FIGS. 1 to 3, the dot point glazing apparatus 10 has a longitudinally extending rod 11 and a vertically extending straight arm 12 which is provided with a boss 13 at its center and a hole 14 at each of its upper and lower ends. The front end portion of the rod 11 penetrates the boss 13. A split pin 15 engages the front end of the rod 11. Thus, the straight arm 12 engages the rod 11 to be rotatable around the rod 11. 
     A V-shaped arm 16a is provided with a tapped hole 17 at each of its right and left upper ends and a tapped hole 18 at its yoke-shaped center. The yoke-shaped center of the V-shaped arm 16a engages the upper end of the straight arm 12. A longitudinally directed headed pin 19 penetrates the tapped hole 18 and the hole 14 disposed at the upper end of the straight arm 12. A split pin 15 engages the front end of the pin 19. Thus, the V-shaped arm 16a engages the upper end of the straight arm 12 to be rotatable around the pin 19. 
     A longitudinally directed bolt 20 penetrates a hole 1 0  formed at left lower corner of a glass plate 1a 1  and a pair of packing rings 21 which are disposed on opposite sides of the glass plate 1a 1 . The bolt 20 is screwed into the tapped hole 17 disposed at the right upper end of the V-shaped arm 16a. Thus the glass plate 1a 1  is connected to the right upper end of the V-shaped arm 16a at its left lower corner. In the same way, a glass plate 1b 1  which is disposed adjacent to and left of the glass plate 1a 1  is connected to the left upper end of the V-shaped arm 16a at its right lower corner. 
     A V-shaped arm 16b which has the same configuration as the V-shaped arm 16a but is inverted with respect thereto engages the lower end of the straight arm 12 to be rotatable in the same way as the V-shaped arm 16a. A glass plate 1a 2  which is disposed adjacent to and below the glass plate 1a 1  is connected to the right lower end of the V-shaped arm 16b and a glass plate 1b 2  which is disposed adjacent to and below the glass plate 1b 1  is connected to the left lower end of the V-shaped arm 16b in the same way as the glass plates 1a 1  and 1b 1 . Spaces between the adjacent glass plates 1a 1 , 1a 2 , 1b 1 , 1b 2  are filled with sealant 22. 
     The rod 11 is connected to a joint member 100 at its rear end. Rods 110 extend upward and downward from the joint member 100. The upwardly extending rod 110 is connected to the joint member 100 to which the rod 11 of the upwardly adjacent dot point glazing apparatus is connected, while the downwardly extending rod 110 is connected to the joint member 100 to which the rod 11 of the downwardly adjacent dot point glazing apparatus is connected. A rod 120 extends rearwardly from the joint member 100. As shown in FIG. 15, the rod 120 is connected to a truss structure 200 which is disposed to the rear of the glass screen 2 at its rear end. 
     Dot point glazing apparatus 30 
     As shown in FIGS. 4 and 5, the dot point glazing apparatus 30 has the same construction as the dot point glazing apparatus 10 except that it does not have the V-shaped arm 16a. 
     The glass plate 1a 1  is connected to the right lower end of the V-shaped arm 16b at its left upper corner and the glass plate 1b 1  is connected to the left lower end of the V-shaped arm 16b at its right upper corner in the same way as the glass plates 1a 2  and 1b 2 . The space between the glass plates 1a 1  and 1b 1  is filled with the sealant 22. 
     The rod 11 is connected to the joint member 100 in the same way as the dot point glazing apparatus 10. The joint member 100 is fixed to the lower surface of a structural member 300 through a bracket 130. The rod 110 which downwardly extends from the joint member 100 is connected to the joint member 100 to which the rod 11 of the downwardly adjacent dot point glazing apparatus is connected. 
     Dot point glazing apparatus 40 
     As shown in FIGS. 6 and 7, the dot point glazing apparatus 40 has the same construction as the dot point glazing apparatus 10 except that it does not have the V-shaped arm 16b. 
     A glass plate la 3 is connected to the right upper end of the V-shaped arm 16a at its left lower corner and a glass plate 1b 3  is connected to the left upper end of the arm 16a at its right lower corner in the same way as the glass plates 1a 1  and 1b 1 . The space between the adjacent glass plates 1a 3  and 1b 3  is filled with the sealant 22. 
     The rod 11 is connected to the joint member 100 in the same way as the dot point glazing apparatus 10. The rod 110 which upwardly extends from the joint member 100 is connected to the joint member 100 to which the rod 11 of the upwardly adjacent dot point glazing apparatus is connected. 
     The rod 120 which extends rearwardly from the joint member 100 is connected to the truss structure 200 in the same way as the dot point apparatus 10. 
     Dot point glazing apparatus 50 
     As shown in FIGS. 8 to 10, the dot point glazing apparatus 50 has a longitudinally extending rod 11 and a vertically extending straight arm 12 which is provided with a boss 13 at its center and a hole 14 at each of its upper and lower ends. The front end portion of the rod 11 penetrates the boss 13. A split pin 15 engages the front end of the rod 11. Thus, the straight arm 12 engages the rod 11 to be rotatable around the rod 11. 
     A vertically extending straight arm 51a is provided with a tapped hole 52 at its upper end and a tapped hole 53 at its yoke-shaped lower end. The yoke-shaped lower end of the straight arm 51a engages the upper end of the straight arm 12. A longitudinally directed headed pin 19 penetrates the tapped hole 53 and the hole 14 disposed at the upper end of the straight arm 12. A split pin 15 engages the front end of the pin 19. Thus, the straight arm 51a engages the upper end of the straight arm 12 to be rotatable around the pin 19. 
     A longitudinally directed bolt 20 penetrates a hole 1 0   formed at the right lower corner of the glass plate 1a 1  and a pair of packing rings 21 which are disposed on opposite sides of the glass plate 1a 1 . The bolt 20 is screwed into the tapped hole 52 disposed at the upper end of the straight arm 51a. Thus the glass plate 1a 1  is connected to the upper end of the straight arm 51a at its right lower corner. 
     A vertically extending straight arm 51b which has the same configuration as the straight arm 51a but is inverted with respect thereto engages the lower end of the straight arm 12 to be rotatable in the same way as the straight arm 51a. A glass plate 1a 2  which is disposed adjacent to and below the glass plate 1a 1  is connected to the lower end of the straight arm 51b at its right upper corner in the same way as the glass plate 1a 1 . The space between the adjacent glass plates 1a 1  and 1a 2  is filled with sealant 22. 
     The rod 11 is connected to a joint member 100 at its rear end. Rods 110 extend upward and downward from the joint member 100. The upwardly extending rod 110 is connected to the joint member 100 to which the rod 11 of the upwardly adjacent dot point glazing apparatus is connected, while the downwardly extending rod 110 is connected to the joint member 100 to which the rod 11 of the downwardly adjacent dot point glazing apparatus is connected. A rod 120 extends rearwardly from the joint member 100. As shown in FIG. 15, the rod 120 is connected to a truss structure 200 which is disposed to the rear of the glass screen 2 at its rear end. 
     Dot point glazing apparatus 60 
     As shown in FIGS. 11 and 12, the dot point glazing apparatus 60 has the same construction as the dot point glazing apparatus 50 except that it does not have the straight arm 51a. 
     A glass plate 1a 1  is connected to the lower end of the straight arm 51b at its right upper corner in the same way as the glass plate 1a 2 . 
     The rod 11 is connected to the joint member 100 in the same way as the dot point glazing apparatus 50. The joint member 100 is fixed to the lower surface of a structural member 300 through a bracket 130. The rod 110 which downwardly extends from the joint member 100 is connected to the joint member 100 to which the rod 11 of the downwardly adjacent dot point glazing apparatus is connected. 
     Dot point glazing apparatus 70 
     As shown in FIGS. 13 and 12, the dot point glazing apparatus 70 has the same construction as the dot point glazing apparatus 50 except that it does not have the straight arm 51b. 
     A glass plate 1a 3  is connected to the upper end of the straight arm 51a at its right lower corner in the same way as the glass plates 1a 1 . 
     The rod 11 is connected to the joint member 100 in the same way as the dot point glazing apparatus 50. The rod 110 which upwardly extends from the joint member 100 is connected to the joint member 100 to which the rod 11 of the upwardly adjacent dot point glazing apparatus is connected. 
     The rod 120 which extends rearwardly from the joint member 100 is connected to a truss structure 200 in the same way as the dot point apparatus 50. 
     The above described dot point glazing apparatuses operate as follows. 
     Dot point glazing apparatus 10 
     The V-shaped arm 16a supports the glass plates 1a 1  and 1b 1  against wind loads directed perpendicular to their surfaces. The V-shaped arm 16b supports the glass plates 1a 1  and 1b 2  against their weights as well as against the wind loads acting on them. The wind loads are transmitted from the V-shaped arms 16a and 16b to the truss structure 200 through the rod 11, the joint member 100 and the rod 120. The weights of the glass plates 1a 1  and 1b 2  together with the weights of the glass plates 1a 3  and 1b 3  are transmitted to the joint member 100 of the upwardly adjacent dot point glazing apparatus 30 through the upwardly extending rod 110. 
     In-plane vertical relative displacements between the glass plates 1a 1  and 1b 1 , and between the glass plates 1a 2  and 1b 2 , are allowed by the rotation of the V-shaped arm 16a and the V-shaped arm 16b respectively, while in-plane horizontal relative displacements between the glass plates 1a 1  and 1a 2 , and between the glass plates 1b 1  and 1b 2 , are allowed by the rotation of the straight arm 12. Thus, a shear deformation of the glass screen 2 is allowed when an earthquake occurs, which protects the glass screen 2 from damage. 
     When the straight arm 12 rotates, a restoring moment is generated by the weights of the glass plates 1a 2  and 1b 1 . Thus, the straight arm 12 readily restores to the original equilibrium state after the earthquake stops. As a result, the in-plane horizontal relative displacements between the glass plates 1a 1  and 1a 2 , and 1b 1  and 1b 2  readily disappear after the earthquake stops, and, therefore, the shear deformation of the glass screen 2 readily disappears after the earthquake stops. 
     When the V-shaped arm 16b rotates, a restoring moment is generated by the weights of the glass plates 1a 1  and 1b 2  because the V-shaped arm 16b is inverted. Thus, the V-shaped arm 16b readily restores to the original equilibrium state after the earthquake stops. As a result, the in-plane vertical relative displacement between the glass plates 1a 2  and 1b 2  readily disappears after the earthquake stops, and, therefore, the shear deformation of the glass screen 2 readily disappears after the earthquake stops. 
     Dot point glazing apparatus 30 
     The V-shaped arm 16b supports the glass plates 1a 1  and 1b 1  against their weights as well as against the wind loads acting on them. The wind loads are transmitted from the arm 16b to the truss structure 200 in the same way as in the dot point glazing apparatus 10. The weights of the glass plates 1a 1  and 1b 1  together with the weights of the glass plates 1a 2  and 1b 2 , 1a 3  and 1b 3  are transmitted to the structural member 300 through the bracket 130. 
     In-plane vertical relative displacement between the glass plates 1a 1  and 1b 1  is allowed by the rotation of the V-shaped arm 16b, while in-plane horizontal displacements of the glass plates 1a 1  and 1b 1  are allowed by the rotation of the straight arm 12. Thus, a shear deformation of the glass screen 2 is allowed when an earthquake occurs, which protects the glass screen 2 from damage. 
     When the straight arm 12 rotates, a restoring moment is generated by the weights of the glass plates 1a 1  and 1b 1 . Thus, the straight arm 12 readily restores to the original equilibrium state after the earthquake stops. As a result, the in-plane horizontal displacements of the glass plates 1a 1  and 1b 1  readily disappear after the earthquake stops, and, therefore, the shear deformation of the glass screen 2 readily disappears after the earthquake stops. 
     When the V-shaped arm 16b rotates, a restoring moment is generated by the weights of the glass plates 1a 1  and 1b 1  because the arm 16b is inverted. Thus, the V-shaped arm 16b readily restores to the original equilibrium state after the earthquake stops. As a result, the in-plane vertical relative displacement between the glass plates 1a 1  and 1b 1  readily disappears after the earthquake stops, and, therefore the shear deformation of the glass screen 2 readily disappears after the earthquake stops. 
     Dot point glazing apparatus 40 
     The V-shaped arm 16a supports the glass plates 1a 3  and 1b 3  against the wind loads acting on them. The wind loads are transmitted from the V-shaped arm 16a to the truss structure 200 in the same way as in the dot point glazing apparatus 10. 
     In-plane vertical relative displacement between the glass plates 1a 3  and 1b 3  is allowed by the rotation of the V-shaped arm 16a, while in-plane horizontal displacement of the glass plates 1a 3  and 1b 3  is allowed by the rotation of the straight arm 12. Thus, a shear deformation of the glass screen 2 is allowed when an earthquake occurs, which protects the glass screen 2 from damage. 
     Dot point glazing apparatus 50 
     The straight arm 51a supports the glass plates 1a 1  against the wind load acting on it. The straight arm 51b supports the glass plate 1a 2  against its weight as well as against the wind load acting on it. The wind load is transmitted from the straight arms 51a, 51b to the truss structure 200 through the rod 11, the joint member 100 and the rod 120. The weight of the glass plate 1a 2  together with the weight of the glass plate 1a 3  are transmitted to the joint member 100 of the upwardly adjacent dot point glazing apparatus 60 through the upwardly extending rod 110. 
     In-plane horizontal relative displacement between the glass plates 1a 1  and 1a 2  is allowed by the rotation of the straight arm 12. Thus, a shear deformation of the glass screen 2 is allowed when an earthquake occurs, which protects the glass screen 2 from damage. 
     When the straight arm 12 rotates, a restoring moment is generated by the weight of the glass plate 1a 2 . Thus, the straight arm 12 readily restores to the original equilibrium state after the earthquake stops. As a result, the in-plane horizontal relative displacement between the glass plates 1a 1  and 1a 2  readily disappears after the earthquake stops, and, therefore, the shear deformation of the glass screen 2 readily disappears after the earthquake stops. 
     Dot point glazing apparatus 60 The straight arm 51b supports the glass plate 1a 1  against its weight as well as against the wind load acting on it. The wind load is transmitted from the arm 51b to the truss structure 200 in the same way as in the dot point glazing apparatus 50. The weight of the glass plate 1a 1  together with the weights of the glass plates 1a 2 , 1a 3  are transmitted to the structural member 300 through the bracket 130. 
     In-plane horizontal displacement of the glass plate 1a 1  at is allowed by the rotation of the straight arm 12. Thus, a shear deformation of the glass screen 2 is allowed when an earthquake occurs, which protects the glass screen 2 from damage. 
     When the straight arm 12 rotates, a restoring moment is generated by the weight of the glass plate 1a 1 . Thus, the straight arm 12 readily restores to the original equilibrium state after the earthquake stops. As a result, the in-plane horizontal displacement of the glass plate 1a 1  readily disappears after the earthquake stops, and, therefore, the shear deformation of the glass screen 2 readily disappears after the earthquake stops. 
     Dot point glazing apparatus 70 
     The straight arm 51a supports the glass plates 1a 3  against the wind load acting on it. The wind load is transmitted from the arms 51a to the truss structure 200 in the same way as in the dot point glazing apparatus 50. 
     In-plane horizontal displacement of the glass plate 1a 3  is allowed by the rotation of the straight arm 12. Thus, a shear deformation of the glass screen 2 is allowed when an earthquake occurs, which protects the glass screen 2 from damage. 
     While the present invention has been described with reference to the preferred embodiments, one of ordinary skill in the art will recognize that modifications and improvements may be made while remaining within the spirit and scope of the present invention. The scope of the invention is determined solely by the appended claims.