Patent Publication Number: US-2022220793-A1

Title: Connecting fitting construction materials and connecting method therefor

Description:
TECHNICAL FIELD 
     The present invention relates to a connecting fitting for construction materials and a connecting method therefor, and more particularly, to a connecting fitting for construction materials and a connecting method therefor that can be used to connect two construction materials spaced apart from each other, more specifically, a construction material on the side of a skeleton such as a wall, and an apparatus-side construction material such as an opening frame, e.g., a door frame of a hinged door apparatus, a sliding door apparatus, or the like. 
     BACKGROUND ART 
     Patent literature 1 below discloses that a door frame, the inside of which is a doorway that is opened and closed by a hinged door, is arranged in a wall as a skeleton of a building. 
     RELATED ART LITERATURE 
     Patent Literature 
     Patent Literature 1: Japanese Utility Model Laid-Open No. 6-10585 
     DISCLOSURE OF INVENTION 
     Problem to be Solved by the Invention 
     The work for arranging an opening frame such as a door frame inside an opening formed in a wall includes a work for arranging the opening frame as a construction material for a hinged door with an interval from a skeleton-side construction material formed on the wall side, and connecting the skeleton-side construction material and the opening frame by using a connecting member. This connecting work is a work for attaching the opening frame to the skeleton-side construction material such that the opening frame is immobile. 
     It is an object of the present invention to provide a connecting fitting for construction materials and a connecting method therefor that can effectively perform the work for connecting two construction materials arranged with an interval therebetween even when this interval is small, and can render one construction material immobile with respect to the other construction material after the connecting work. 
     Means of Solution to the Problem 
     A connecting fitting for construction materials according to the present invention is a connecting fitting for construction materials, which connects two construction materials arranged with an interval therebetween, the connecting fitting including a first connecting member and a second connecting member that are inserted between the two construction materials, and function as members for connecting the two construction materials, and parallelizing means having a parallelizing function of aligning the first connecting member and the second connecting member in a first direction perpendicular to both a thickness direction of one of the two construction materials and a direction of the interval, and making the first connecting member and the second connecting member parallel or almost parallel to each other, wherein the parallelizing means can eliminate the parallelizing function by a load caused to act on at least one of the first connecting member and the second connecting member, and inclination angles, with respect to the direction of the interval, of the first connecting member and the second connecting member aligned parallel or almost parallel to each other in the first direction by the parallelizing means can be made opposite to each other by the elimination of the parallelizing function. 
     In the connecting fitting for construction materials according to the present invention, when the first and second connecting members are inserted between two construction materials, the parallelizing function of the parallelizing means makes these connecting members parallel or almost parallel in the first direction. Even when the interval between the two construction materials is small, therefore, the first and second connecting members can sufficiently be inserted into this interval. 
     Also, after the first and second connecting members are inserted between the two construction materials, the parallelizing function of the parallelizing means disappears, and this makes the inclination angles of the connecting members with respect to the direction of the interval opposite to each other. In this state, the two construction materials can be connected by the first and second connecting members. Accordingly, one of the two construction materials can be rendered immobile in the first direction with respect to the other construction material. 
     In the connecting fitting for construction materials according to the present invention as described above, the parallelizing function of the parallelizing means makes the first and second connecting members parallel or almost parallel in the first direction. In addition, after these connecting members are inserted between two construction materials, the inclination angles of these connecting members with respect to the direction of the interval between the two construction materials are made opposite to each other. This can be implemented by inserting a central shaft having an axial direction in the thickness direction of one of the two construction materials into one of the two end portions of each of the first and second connecting members, and making the first and second connecting members pivotable around this central shaft. 
     This central shaft may also be used for each of the first and second connecting members. In this case, two central shafts are used. It is also possible to use one central shaft common to the first and second connecting members. The use of one central shaft common to the first and second connecting members can reduce the number of members and the manufacturing cost by the use of a common member. 
     Also, the parallelizing means can be an arbitrary means provided that the means has the parallelizing function that aligns the first and second connecting members in the first direction and makes them parallel or almost parallel to each other, and that this parallelizing function can disappear due to a load acting on at least one of the first and second connecting members. One example of this parallelizing means is a projecting piece that is formed in at least one of the first and second connecting members, projects toward the other connecting member, and is in contact with the other connecting member. It is only necessary to make this projecting piece bendable by the load acting on at least one of the first and second connecting members, and eliminate the parallelizing function by this bending. 
     Another example of the parallelizing means is a frictional means interposed between the first and second connecting members. The frictional force of this frictional means acts as the parallelizing function, and makes it possible to align the first and second connecting members in the first direction and make them parallel or almost parallel to each other. Also, this parallelizing means is so configured that the parallelizing function disappears when a load larger than the frictional force acts on at least one of the first and second connecting members, and the inclination angles of the first and second connecting members with respect to the direction of the interval between the two construction materials are made opposite to each other. 
     Still another example of the parallelizing means is a projection/recess means including a recess formed in one of the first and second connecting members, and a projection that is formed in the other connecting member and detachably fits in the recess. When the projection fits in the recess, the parallelizing function arises, so the first and second connecting members can be aligned in the first direction and made parallel or almost parallel to each other. In addition, the parallelizing means is so configured that when the abovementioned load acts on at least one of the first and second connecting members, the parallelizing function disappears because the projection escapes from the recess, and the inclination angles of the first and second connecting members with respect to the direction of the interval between the two construction materials are made opposite to each other. 
     When using the above-described projecting piece as the parallelizing means, it is also possible to form a strength decreasing portion having low strength in that portion of one connecting member, which is close to the projecting piece, and make the projecting piece bendable with a small load by this strength decreasing portion. 
     Since, therefore, the projecting piece can easily be bent from the strength decreasing portion by a small load acting on one connecting member, an operation can easily be performed on one connecting member in order to eliminate the parallelizing function of the parallelizing means. 
     Note that the strength decreasing portion can be an arbitrary portion as long as the portion decreases the strength of one connecting member. An example of the strength decreasing portion is a notch formed in one connecting member. Another example of the strength decreasing portion is a thin portion formed in one connecting member. 
     It is also possible to form two strength decreasing portions on the two sides of the projecting piece. The two strength decreasing portions can make the projecting piece bendable by a smaller load. 
     A connecting method for construction materials according to the present invention is a connecting method for construction materials, which connects two construction materials arranged with an interval therebetween, the connecting method including a first working step of aligning a first connecting member and a second connecting member in a direction perpendicular to both a thickness direction of one of the two construction materials and a direction of the interval, and making the first connecting member and the second connecting member parallel or almost parallel to each other, by a parallelizing function of parallelizing means formed in at least one of the first connecting member and the second connecting member, and inserting the first connecting member and the second connecting member between the two construction materials in this state, a second working step of making inclination angles of the first connecting member and the second connecting member with respect to the direction of the interval opposite to each other by elimination of the parallelizing function of the parallelizing means, after the first working step, and a third working step of connecting the two construction materials by the first connecting member and the second connecting member, after the second working step. 
     In the first working step of this connecting method for construction materials, the first and second connecting members are inserted between two construction materials in a state in which the first and second connecting members are aligned in the first direction and made parallel or almost parallel to each other by the parallelizing function of the parallelizing means. Even when the interval between these construction materials is small, therefore, the first and second connecting members can sufficiently be inserted into this interval. 
     Also, in the second working step after the first and second connecting members are inserted between the two construction materials, the parallelizing function of the parallelizing means disappears, so the inclination angles of the first and second connecting members with respect to the direction of the interval between the two construction materials become opposite to each other. In this state, the first and second connecting members connect the two construction materials in the third working step. This can render one of the two construction materials immobile in the first direction with respect to the other construction material. 
     Two construction materials to be connected by the connecting fitting for construction materials and the connecting method therefor according to the present invention explained above can be arbitrary construction materials. One example of these construction materials includes a skeleton-side construction material such as a wall, and an opening frame arranged to oppose this construction material in the horizontal direction. This opening frame can be any of a door frame for a hinged door apparatus, an opening frame for a sliding door apparatus, and an opening frame for a passing opening to be formed in a wall. Also, one of the two construction materials can be a door case for accommodating a fire door that is normally opened from a door frame. In addition, the connecting fitting for construction materials and the connecting method therefor according to the present invention can also be used to connect two construction materials such as pillars including a middle pillar of a building, beams, crossbars, and face plates, that is, the present invention is applicable to arbitrary construction materials. 
     Furthermore, the connecting fitting for construction materials and the connecting method therefor according to the present invention are applicable to construction materials to be newly formed in a structure such as a building, and are also applicable to construction materials to be repaired. 
     Effect of the Invention 
     The present invention achieves the effect of effectively performing the work for connecting two construction materials arranged with an interval therebetween even when this interval is small, and rendering one construction material immobile with respect to the other construction material after the connecting work. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a whole front view of a hinged door apparatus to which a connecting fitting for construction materials according to an embodiment of the present invention is applied; 
         FIG. 2  is a whole front view showing a door frame as a construction material on the side of the hinged door apparatus; 
         FIG. 3  is a whole front view showing a structure in which first and second connecting fittings connect a door frame and a reinforcing member as a skeleton-side construction material via an auxiliary member attached to the reinforcing member; 
         FIG. 4  is a sectional view taken along a line S 4 -S 4  shown in  FIG. 3 ; 
         FIG. 5  is a perspective view showing the whole first connecting fitting shown in  FIG. 3  by including the auxiliary member shown in  FIGS. 3 and 4 ; 
         FIG. 6  is a front view of  FIG. 5 ; 
         FIG. 7A  is a plan view showing a first connecting member as a constituting member of the first and second connecting fittings; 
         FIG. 7B  is a side view of  FIG. 7A ; 
         FIG. 7C  is a bottom view of  FIG. 7A ; 
         FIG. 7D  is a rear view of  FIG. 7A ; 
         FIG. 8A  is a plan view showing the first connecting member when loads act; 
         FIG. 8B  is a side view of  FIG. 8A ; 
         FIG. 8C  is a bottom view of  FIG. 8A ; 
         FIG. 9A  is a side view showing a second connecting member as a constituting member of the first connecting fitting; 
         FIG. 9B  is a rear view of  FIG. 9A ; 
         FIG. 10  is a front view showing, by the solid lines, a state in which the first and second connecting members of the first connecting fitting shown in  FIGS. 5 and 6  are parallel or almost parallel to each other; 
         FIG. 11  is a side view showing the first connecting fitting when the first and second connecting members are in the state indicated by the solid lines in  FIG. 10 ; 
         FIG. 12  is a sectional view taken along a line S 12 -S 12  shown in  FIG. 11 ; 
         FIG. 13  is a side view showing the first connecting fitting when the first and second connecting members are doglegged as shown in  FIGS. 5 and 6 ; 
         FIG. 14  is a sectional view taken along a line S 14 -S 14  shown in  FIG. 13 ; 
         FIG. 15  is a view similar to  FIG. 4 , showing a state before the first and second connecting members are coupled with the auxiliary member attached to the reinforcing member shown in  FIG. 4  by using coupling fittings; 
         FIG. 16  is a view similar to  FIG. 13 , showing a state in which the first and second connecting members are coupled with the reinforcing member indicated by the alternate long and two short dashed lines by using the coupling fittings; 
         FIG. 17  is a view similar to  FIG. 4 , showing the state of  FIG. 16 ; 
         FIG. 18  is an enlarged sectional view showing a state in which the first connecting member of the first connecting fitting is locked by a central shaft as a locked member in the state shown in  FIGS. 16 and 17 ; 
         FIG. 19  is a view similar to  FIG. 16 , showing a state in which the first and second connecting members are coupled with the auxiliary member attached to the reinforcing member by using the coupling fittings arranged on the same side in the axial direction of the central shaft; 
         FIG. 20  is a view similar to  FIG. 4 , showing the state of  FIG. 19 ; 
         FIG. 21  is a plan sectional view showing the structure of a building to which the coupling fittings shown in  FIGS. 19 and 20  are applicable; 
         FIG. 22A  is a side view showing a first connecting member according to another embodiment; 
         FIG. 22B  is a rear view of  FIG. 22A ; and 
         FIG. 23  is a side view showing a state in which loads for coupling the first connecting member shown in  FIGS. 22A and 22B  with the auxiliary member attached to the reinforcing member shown in  FIG. 4  by using the coupling fittings act on the first connecting member. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     A mode for carrying out the present invention will be explained below with reference to the accompanying drawings.  FIG. 1  shows a whole front view of a hinged door apparatus. In this hinged door apparatus, a hinged door  1  is attached to a door frame  2  so as to be pivotal around hinges  3 , and the door frame  2  is arranged inside an opening  4 A formed in a wall  4  as a building skeleton.  FIG. 2  shows the door frame  2  before the hinged door  1  is attached. As shown in  FIG. 2 , the door frame  2  is an opening frame as a doorway  11  the inside of which is opened and closed by the hinged door  1 . Since the door frame  2  of this embodiment is a four-side frame, the door frame  2  includes left and right side frame members  2 A and  2 B, an upper frame member  2 C, and a lower frame member  2 D as a doorsill member. The frame members  2 A,  2 B,  2 C, and  2 D are welded in a factory beforehand, and transported to the construction site of a structure such as a building in which the opening apparatus is installed. 
     Note that the door frame  2  may also be a three-side frame having no lower frame member  2 D. 
       FIG. 3  shows a state in which the door frame  2  is arranged in the wall  4  shown in  FIGS. 1 and 2 .  FIG. 4  is a sectional view taken along a line S 4 -S 4  shown in  FIG. 3 . As shown in  FIG. 4 , the wall  4  shown in  FIGS. 1 and 2  is a building skeleton formed by fixing face plates  6  such as plaster boards on both the front and rear surfaces of core members  5 . The door frame  2  is arranged inside the opening  4 A shown in  FIGS. 1 and 2  formed in the wall  4 . Of a large number of core members  5  formed inside the wall  4 ,  FIG. 3  shows core members  5 A and  5 B arranged in portions opposing, in the horizontal direction, the left and right side frame members  2 A and  2 B of the door frame  2 , and a core member  5 C arranged in a portion opposing the upper frame member  2 C of the door frame  2  in the vertical direction. 
     Before the work for arranging the door frame  2  inside the opening  4 A of the wall  4 , reinforcing members  7  shown in  FIGS. 3 and 4  are coupled with the core members  5 A,  5 B, and  5 C in advance. Also, an auxiliary member  8  is attached to each reinforcing member  7  by a fixing fitting  9  shown in  FIG. 4 . A crank-shaped positioning member  10  is coupled with each auxiliary member  8 . After each positioning member  10  is brought into contact with one of the two surfaces of the reinforcing member  7  in the thickness direction of the door frame  2  (the thickness direction of the hinged door  1  and the wall  4 ), the auxiliary member  8  is attached to the reinforcing member  7  by the fixing fitting  9 . Consequently, each auxiliary member  8  is set in a predetermined position in the thickness direction of the door frame  2  and attached to the reinforcing member  7 . 
     In the above explanation, the core member  5 , the reinforcing member  7 , and the auxiliary member  8  are members of the wall  4  as a building skeleton, so the core member  5 , the reinforcing member  7 , and the auxiliary member  8  are skeleton-side construction materials. On the other hand, the hinged door  1  and the door frame  2  are members of the hinged door apparatus to be installed in the wall  4 , so the hinged door  1  and the door frame  2  are hinged door apparatus-side construction materials. 
       FIG. 3  shows a state in which after the work for arranging the door frame  2  inside the opening  4 A of the wall  4  is performed, the door frame  2  is connected to the reinforcing member  7  via the auxiliary member  8  by using a connecting fitting  20 . A plurality of connecting fittings  20  are formed for each of the left and right side frame members  2 A and  2 B and the upper frame member  2 C of the door frame  2 , and connect the door frame  2  to the reinforcing members  7  via the auxiliary members  8 . As the connecting fittings  20 , a plurality of first connecting fittings  20 A and two second connecting fittings  20 B are used. The first connecting fitting  20 A includes first and second connecting members  21  and  22 , whereas the second connecting fitting  20 B includes the first connecting member  21  but does not include the second connecting member  22 . The plurality of first connecting fittings  20 A have the same shape and the same structure. Therefore,  FIGS. 5 and 6  illustrate, as a typical example of the plurality of first connecting fittings  20 A shown in  FIG. 3 , the first connecting fitting  20 A that is arranged on the side frame member  2 A of the door frame  2  shown in  FIG. 4  and connects the side fame member  2 A to the auxiliary member  8  attached to the reinforcing member  7  coupled with the core member  5 A described earlier.  FIGS. 5 and 6  do not show the side frame member  2 A. 
     Note that the two second connecting fittings  20 B shown in  FIG. 3  also have the same shape and the same structure. As shown in  FIG. 3 , the second connecting fittings  20 B are arranged below the plurality of first connecting fittings  20 A vertically arranged on each of the left and right side frame members  2 A and  2 B. 
       FIG. 5  shows a perspective view of the first connecting fitting  20 A by including the auxiliary member  8 .  FIG. 6  is a front view of  FIG. 5 . As is also shown in  FIG. 4 , the first connecting fitting  20 A includes a bearing member  23  formed into the shape of a hat, a central shaft  24  supported by the bearing member  23 , and the first and second connecting members  21  and  22  described above. The thickness direction of the door frame  2  is an axial direction N of the central shaft  24 , and the two end portions in the axial direction N function as retaining portions  24 A and retain the central shaft  24 . As shown in  FIG. 4 , the central shaft  24  is inserted, as an insertion member common to the first and second connecting members  21  and  22 , through the end portions, on the side of the door frame  2 , of the first and second connecting members  21  and  22 . The first and second connecting members  21  and  22  can freely pivot around the central shaft  24 . Also, the end portion, on the side of the wall  4 , of the first connecting member  21  is coupled with the auxiliary member  8  by coupling fittings  25  as self-drill screws. Likewise, the end portion, on the side of wall  4 , of the second connecting member  22  is coupled with the auxiliary member  8  by coupling fittings  34  as self-drill screws. 
       FIGS. 7A, 7B, 7C, and 7D  depict the first connecting member  21 .  FIGS. 7A, 7B, 7C, and 7D  are respectively a plan view, a side view, a bottom view, and a rear view of the first connecting member  21 . The first connecting member  21  is a product obtained by punching and bending a metal plate. The first connecting member  21  includes two connecting parts  26  opposing each other. The two connecting parts  26  are separated from each other in the axial direction N of the central shaft  24 , and coupled with each other by a bridge part  27  for which the axial direction N of the central shaft  24  is the widthwise dimension. The bridge part  27  is bridged between the end portions of the two connecting parts  26 , on the side of the thickness direction of the whole first connecting member  21  perpendicular to the axial direction N of the central shaft  24 . Also, assuming that a direction perpendicular to the axial direction N of the central shaft  24  and perpendicular to the thickness direction of the whole first connecting member  21  is the longitudinal direction of each connecting part  26 , the dimension of each connecting part  26  in the longitudinal direction is a dimension by which two end portions  26 A and  26 B of the connecting part  26  in the longitudinal direction reach the door frame  2  and the auxiliary member  8  as the skeleton of the wall  4 . 
     As shown in  FIGS. 7A and 7C , the end portion  26 A, on the side of the auxiliary member  8 , of the two end portions  26 A and  26 B of each connecting part  26  in the longitudinal direction has a torsion angle α as an angle inclining to the outside of the first connecting member  21  with respect to the axial direction N of the central shaft  24 . The torsion angles a of the two connecting parts  26  are torsion angles in directions opposite to each other. On the other hand, as shown in  FIGS. 7A and 7C , the end portion  26 B on the side of the door frame  2  has no such torsion angle as described above. A portion between the end portions  26 A and  26 B is an intermediate portion  26 C for gradually eliminating the torsion angle α. The end portion  26 B on the side of the door frame  2  has a first hole  28  having a large diameter, as an insertion portion for inserting the central shaft  24 , and the end portion  26 A on the side of the auxiliary member  8  has a small-diameter second hole  29  for inserting the coupling fitting  25  shown in  FIG. 4 . The connecting parts  26  also have third holes  30  for inserting coupling fittings  50  and  51  to be described later with reference to  FIGS. 19 and 20 , within the range in which the above-described torsion angle α exists. 
     Furthermore, the bridge part  27  has an elongated hole  31 . The elongated hole  31  is elongated in the longitudinal direction of the connecting part  26 , and functions as a strength decreasing portion formed in the bridge part  27  in order to decrease the strength of the bridge part  27 . 
     As described above, the first connecting member  21  is formed by the two connecting parts  26  and the bridge part  27  bridged between the connecting parts  26 , and the section perpendicular to the longitudinal direction is an almost U-shaped section. However, the end portions  26 A, on the side of the auxiliary member  8 , of the two connecting parts  26  open to the outside of the first connecting member  21  due to the torsion angles a described above. In other words, the end portions  26 A form an inverted V-shape that opens outward in the axial direction N of the central shaft  24 . 
       FIGS. 8A, 8B, and 8C  depict a state in which loads W in directions opposite to each other in the axial direction N of the central shaft  24  act on the end portions  26 A, on the side of the auxiliary member  8 , of the connecting parts  26 . A state like this occurs when the coupling fitting  25  shown in  FIG. 4  couples the end portions  26 A, on the side of the auxiliary member  8 , of the connecting parts  26 , with the auxiliary member  8 . When the loads W as described above act on the end portions  26 A on the side of the auxiliary member  8 , the torsion angles a shown in  FIGS. 7A and 7C  of the end portions  26 A on the side of the auxiliary member  8  reduce or disappear, and the influence of the loads W deforms, e.g., curves the bridge part  27  in a direction projecting to the outside of the first connecting member  21 , in the thickness direction of the bridge part  27  (the thickness direction of the whole first connecting member  21 ). The influence of the loads W also generates torsion angles β as angles inclining to the inside of the first connecting member  21  with respect to the axial direction N of the central shaft  24 , on the end portions  26 B on the side of the door frame  2 , which are connected to the end portions  26 A on the side of the auxiliary member  8  via the intermediate portion  26 C. The torsion angles β are torsion angles in directions opposite to each other with respect to the end portions  26 B on the side of the door frame  2 . 
     In the whole first connecting member  21 , therefore, the shape formed by the end portions  26 B, on the side of the door frame  2 , of the two connecting parts  26  is a V-shape that closes to the outside of the first connecting member  21  due to the torsion angles β. 
     Note that the elongated hole  31  is formed in the bridge part  27  and decreases the strength of the bridge part  27 , so the bridge part  27  is easily deformed, e.g., curved as described above, due to the loads W. Accordingly, the reduction or elimination of the torsion angles α of the end portions  26 A on the side of the auxiliary member  8  and the generation of the torsion angles β of the end portions  26 B on the side of the door frame  2  occur more reliably. 
       FIGS. 9A and 9B  show the second connecting member  22 .  FIGS. 9A and 9B  are respectively a side view and a rear view of the second connecting member  22 . Like the first connecting member  21 , the second connecting member  22  is a product obtained by punching and bending a metal plate. The second connecting member  22  also includes two connecting parts  35  opposing each other. The two connecting parts  35  are separated from each other in the axial direction N of the central shaft  24 , and coupled with each other by a bridge part  36  for which the axial direction N of the central shaft  24  is the widthwise dimension. The bridge part  36  is bridged between the end portions of the two connecting parts  35 , on the side of the thickness direction of the whole second connecting member  22  perpendicular to the axial direction N of the central shaft  24 . Also, assuming that a direction perpendicular to the axial direction N of the central shaft  24  and perpendicular to the thickness direction of the whole second connecting member  22  is the longitudinal direction of each connecting part  35 , the dimension of each connecting part  35  in the longitudinal direction is a dimension by which two end portions  35 A and  35 B of the connecting part  35  in the longitudinal direction reach the door frame  2  and the auxiliary member  8  as the skeleton of the wall  4 . 
     Also, of the two end portions  35 A and  35 B in the longitudinal direction of each connecting part  35 , the end portion  35 A on the side of the auxiliary member  8  slightly bends toward the inside of the second connecting member  22  with respect to the end portion  35 B on the side of the door frame  2 . Of the end portions  35 A and  35 B, the end portion  35 B on the side of the door frame  2  has a first hole  37  having a large diameter, as an insertion portion for inserting the central shaft  24 , and the end portion  35 A on the side of the auxiliary member  8  has a second hole  38  having a small diameter, as an insertion portion for inserting the coupling fitting  34  shown in  FIG. 4 . In addition, the connecting parts  35  have third holes  39  for inserting the coupling fittings  50  and  51  to be described later with reference to  FIGS. 19 and 20 . 
     Furthermore, the end portion  36 B, on the side of the door frame  2 , of the bridge part  36  has a projecting piece  40  that projects toward the central shaft  24 , in other words, projects toward the first connecting member  21 . The end portion  36 B of the bridge part  36  has notches  41  in portions close to the projecting piece  40 . In the end portion  36 B of this embodiment, two notches  41  are formed on the two sides of the projecting piece  40 . Note that as shown in  FIG. 9B , the projecting piece  40  of this embodiment is so formed as to slightly bend from the bridge part  36  to the inside of the second connecting member  22  in the thickness direction. 
     The projecting piece  40  formed in the second connecting member  22  as described above can be bent in the thickness direction of the whole second connecting member  22  if a load acts on the projecting piece  40  in this thickness direction. The two notches  41  of the end portion  36 B of the bridge part  36 , which are formed on the two sides of the projecting piece  40 , function as strength decreasing portions for decreasing the strength of the proximal end portion of the projecting piece  40  in the bridge part  27 . Therefore, the projecting piece  40  can easily be bent even if the abovementioned load acting on the projecting piece  40  is small. 
     In a factory for manufacturing the door frame  2 , the first connecting fitting  20 A including the first connecting member  21 , the second connecting member  22 , the bearing member  23 , and the central shaft  24  explained above is assembled into a structure shown in  FIG. 10  (a front view of the first connecting fitting  20 A) and  FIG. 11  (a side view of the first connecting fitting  20 A). This assembling is performed by, e.g., inserting the central shaft  24  as a common insertion member into the first holes  28  formed in the connecting parts  26  of the first connecting member  21  and the first holes  37  formed in the connecting parts  35  of the second connecting member  22 , further inserting the central shaft  24  into the hat-shaped bearing member  23 , and performing processing that forms the retaining portions  24 A on the two end portions of the central shaft  24  in order to prevent removal from the bearing member  23 . 
     Note that the central shaft  24  according to this embodiment is a male screw rod on the surface of which many projections and recesses are alternately formed in the axial direction by thread ridges and grooves. 
       FIG. 12  is a sectional view taken along a line S 12 -S 12  shown in  FIG. 11 .  FIG. 12  shows the sectional view of the first connecting fitting  20 A assembled by the first connecting member  21 , the second connecting member  22 , the bearing member  23 , and the central shaft  24  as described above. In the first connecting fitting  20 A assembled in a factory, the projecting piece  40  formed in the second connecting member  22  is in contact with a rear surface  27 A of the bridge part  27  formed in the first connecting member  21 . Therefore, the first and second connecting members  21  and  22  for which the central shaft  24  is a common insertion member is connected by the central shaft  24 . Also, the first and second connecting members  21  and  22  are parallel or almost parallel to each other in a direction perpendicular to the axial direction N of the central shaft  24 . 
     Accordingly, the projecting piece  40  forms a parallelizing means  45  that aligns the first and second connecting members  21  and  22  in the direction perpendicular to the axial direction N of the central shaft  24  and makes first and second connecting members  21  and  22  parallel or almost parallel to each other. Also, as will be described later, when the first connecting fitting  20 A is inserted into the gap between the door frame  2  shown in  FIG. 3  and the auxiliary member  8  as a construction material of the wall, the parallelizing function of the parallelizing means  45  can align the first and second connecting members  21  and  22  in a direction (the vertical direction for the first connecting fitting  20 A arranged in the side frame members  2 A and  2 B of the door frame  2 , and the horizontal direction for the first connecting fitting  20 A arranged in the upper frame member  2 C of the door frame  2 ) perpendicular to the direction of the interval between the door frame  2  and the auxiliary member  8 , and to the thickness direction of the door frame  2  (that is also the thickness direction of the wall  4  shown in  FIGS. 1 and 2 ), thereby making the first and second connecting members  21  and  22  parallel or almost parallel to each other. 
     As shown in  FIG. 4 , in the factory having manufactured the door frame  2 , the first connecting fitting  20 A described above is attached to the door frame  2  by fixing the bearing member  23  to the left and right side frame members  2 A and  2 B and the upper frame member  2 C of the door frame  2  by welding or the like. The second connecting fitting  20 B shown in  FIG. 3  includes the first connecting member  21 , the bearing member  23 , and the central shaft  24 . Accordingly, the second connecting fitting  20 B has a structure obtained by removing the second connecting member  22  from the first connecting fitting  20 A. The second connecting fitting  20 B as described above is also attached to the door frame  2  in the factory by fixing the bearing member  23  to the left and right side frame members  2 A and  2 B of the door frame  2 . 
     The door frame  2  to which the first and second connecting fittings  20 A and  20 B are attached in the factory is transported to a construction site where the hinged door apparatus shown in  FIG. 1  is to be installed. After that, before the face plates  6  (see  FIG. 4 ) of the wall  4  (see  FIG. 2 ) are attached to the core members  5 , the first and second connecting fittings  20 A and  20 B are inserted into the horizontal interval between the auxiliary member  8  and the left and right side frame members  2 A and  2 B of the door frame  2 , and the first connecting fitting  20 A is inserted into the vertical interval between the auxiliary member  8  and the upper frame member  2 C of the door frame  2 . Consequently, the door frame  2  and the first and second connecting fittings  20 A and  20 B are arranged inside the opening  4 A of the wall  4  shown in  FIGS. 1 and 2 . In this state, the auxiliary member  8  is attached to the reinforcing member  7  coupled with the core members  5 A,  5 B, and  5 C (see  FIG. 3 ), thereby forming the wall  4  shown in  FIG. 2 . Note that the work for attaching the auxiliary member  8  to the reinforcing member  7  is performed immediately before the work for arranging the door frame  2  and the first and second connecting fittings  20 A and  20 B inside the opening  4 A of the wall  4  as described above. 
     In this embodiment, when performing the work for arranging the door frame  2  and the first and second connecting fittings  20 A and  20 B inside the opening  4 A of the wall  4  as described above, for the first connecting fitting  20 A, among the plurality of first connecting fittings  20 A, which is inserted into the horizontal interval between the auxiliary member  8  and the side frame members  2 A and  2 B of the door frame  2 , the parallelizing function of the parallelizing means  45  described above can make the first and second connecting members  21  and  22  parallel or almost parallel to each other while aligning the first and second connecting members  21  and  22  in the vertical direction perpendicular to the horizontal direction as the interval between the reinforcing member  7  and the side frame members  2 A and  2 B, and to the thickness direction of the door frame  2 , even when the first and second connecting members  21  and  22  can pivot around the central shaft  24 . Also, for the first connecting fitting  20 A to be inserted into the vertical interval between the upper frame member  2 C of the door frame  2  and the auxiliary member  8  attached to the reinforcing member  7  coupled with the core member  5 C, the parallelizing function of the parallelizing means  45  can make the first and second connecting members  21  and  22  parallel or almost parallel to each other while aligning the first and second connecting members  21  and  22  in the horizontal direction perpendicular to the vertical direction as the interval between the upper frame member  2 C and the reinforcing member  7 , and to the thickness direction of the door frame  2 . 
     As described above, therefore, even when the first and second connecting members  21  and  22  of the first connecting fitting  20 A are pivotable around the central shaft  24 , and the horizontal interval between the reinforcing member  7  and the side frame members  2 A and  2 B and the vertical interval between the upper frame member  2 C and the reinforcing member  7  are small, the first connecting fitting  20 A can effectively be inserted into these intervals. This insertion work can be performed by standing up only the first connecting member  21  of the second connecting fitting  20 B around the central shaft  24  of the second connecting fitting  20 B. Since a few workers can easily finish the insertion work within a short time period, the workability can be improved. 
     After inserting the plurality of first connecting fittings  20 A into the horizontal interval between the auxiliary member  7  and the side frame members  2 A and  2 B and into the vertical interval between the upper frame member  2 C and the reinforcing member  7  as described above, the worker performs the work for pivoting at least one of the first and second connecting members  21  and  22  of the first connecting fittings  20 A toward the side frame members  2 A and  2 B and the upper frame member  2 C around the central shaft  24  with respect to the other connecting member. This pivoting work can be performed by, e.g., inserting a tool or the like into the second and third holes  29  and  30  of the first connecting member  21  shown in  FIGS. 7A, 7B, and 7D , and into the second and third holes  38  and  39  of the second connecting member  22  shown in  FIGS. 9A and 9B . 
       FIG. 13  shows the side view of the first connecting fitting  20 A after this pivoting work is performed.  FIG. 14  is the sectional view of the first connecting fitting  20 A taken along a line S 14 -S 14  shown in  FIG. 13 . As shown in  FIG. 14 , when the above-described pivoting work is performed, the projecting piece  40  formed in the second connecting member  22  and in contact with the rear surface  27 A of the bridge part  27  of the first connecting member  21  bends from the portion connected to the bridge part  36  of the second connecting member  22  due to the load of the pivoting work by the worker, and this eliminates the parallelizing function of the parallelizing means  45 . Consequently, for the first connecting fitting  20 A, among the plurality of connecting fittings  20 A, which is inserted into the interval between the reinforcing member  7  and the side frame members  2 A and  2 B, the first and second connecting members  21  and  22  are pivoted around the central shaft  24 , as indicated by the alternate long and two short dashed lines shown in  FIG. 10 , such that inclination angles  01  and  02  with respect to a horizontal direction M as the direction of the interval between the reinforcing member  7  and the side frame members  2 A and  2 B are angles in directions opposite to each other. This makes it possible to insert (see  FIG. 15 ) the auxiliary member  8  between the end portions  26 A and between the end portions  35 A, on the side of the auxiliary member  8 , of the two connecting parts  26  and  35  (see  FIGS. 7A to 7D  and  FIG. 9B ) of the first and second connecting members  21  and  22 . Also, for the first connecting fitting  20 A inserted into the interval between the upper frame work  2 C and the auxiliary member  8 , the first and second connecting members  21  and  22  are pivoted around the central shaft  24  such that inclination angles with respect to the vertical direction as the direction of the interval between the upper frame member  2 C and the reinforcing member  7  are angles in directions opposite to each other. This makes it possible to insert the auxiliary member  8  between the end portions  26 A and between the end portions  35 A, on the side of the auxiliary member  8 , of the two connecting parts  26  and  35  of the first and second connecting members  21  and  22 . 
     In each first connecting fitting  20 A, therefore, the first connecting member  21  forms an inclination angle with respect to the direction of the interval between the auxiliary member  8  and the side frame members  2 A and  2 B, and to the direction of the interval between the upper frame member  2 C and the auxiliary member  8 , and the second auxiliary member  22  forms an inclination angle in a direction opposite to that of the inclination angle of the first auxiliary member, with respect to the direction of the interval between the auxiliary member  8  and the side frame members  2 A and  2 B, and to the direction of the interval between the auxiliary member  8  and the upper frame member  2 C. 
     Note that in the first connecting fittings  20 A, the second connecting member  22  has the two notches  41  formed on the two sides of the projecting piece  40  of the second connecting member  22  as described above. Therefore, the worker can reliably bend the projecting piece  40  even when the load of the above-described pivoting work for bending the projecting piece  40  from the portion connected to the bridge part  36  of the second connecting member  22  is small. 
     Furthermore, in this embodiment, the central shaft  24  as the constituting member of the first connecting fitting  20 A is an insertion member inserted into both the first and second connecting members  21  and  22  of the first connecting member  20 A in order to make the first and second connecting members  21  and  22  pivotable. Accordingly, the number of members constituting the first connecting fitting  20 A can be reduced compared to a case in which a central shaft for making each of the first and second connecting members  21  and  22  pivotable is used for each of the first and second connecting members  21  and  22 . This makes it possible to simplify the structure and reduce the manufacturing cost. 
       FIG. 15  shows a state in which the auxiliary member  8  is inserted between the end portions  26 A and between the end portions  35 A, on the side of the auxiliary member  8 , of the two connecting parts  26  and  35  in the first and second connecting members  21  and  22  of the first connecting fitting  20 A as described above. 
     After performing the above-described work, the worker inserts the two coupling fittings  25  (see  FIGS. 4 and 13 ) into the second holes  29  (see  FIGS. 7A, 7B, and 7C ) formed in the connecting part  26  of the first connecting member  21  of the first connecting fitting  20 A (see  FIG. 3 ), and screws the two coupling fittings  25  into the auxiliary member  8 , thereby coupling the end portion, on the side of the auxiliary member  8 , of the first connecting member  21  with the auxiliary member  8  as shown in  FIGS. 16 and 17 . Also, the worker inserts the two coupling fittings  34  (see  FIGS. 4 and 13 ) into the second holes  38  (see  FIGS. 9A and 9B ) formed in the connecting part  35  of the second connecting member  22  of the first connecting fitting  20 A, and screws the two coupling fittings  34  into the auxiliary member  8 , thereby coupling the end portion, on the side of the auxiliary member  8 , of the second connecting member  22  with the auxiliary member  8  as shown in  FIGS. 16 and 17 . 
     Furthermore, for each of the two second connecting fittings  20 B (see  FIG. 3 ) arranged in the lowermost portions of the left and right side frame members  2 A and  2 B of the door frame  2 , the worker pivots the first connecting member  21  around the central shaft  24 , and makes the angle (see  FIG. 10 ) of the first connecting member  21  in above-described horizontal direction M the same as or almost the same as the inclination angle θ 1  of the first connecting member  21  of the first connecting fitting  20 A described above, and couples the end portion, on the side of the auxiliary member  8 , of the first connecting member  21  with the auxiliary member  8  by using the two coupling fittings  25 . 
     Note that the second connecting fittings  20 B are formed without using the second connecting member  22  because the second connecting fittings  20 B can effectively be arranged in the lowermost portions of the left and right side frame members  2 A and  2 B by omitting the second connecting member  22  that is supposed to be arranged below the first connecting member  21 . 
     When the coupling work for coupling the first and second connecting fittings  20 A and  20 B by using the coupling fittings  25  and  34  as described above, the door frame  2  is connected to the auxiliary member  8  via the two connecting portions  26  of the first connecting member  21  and the two connecting parts  35  of the second connecting member  22  of the plurality of first connecting fittings  20 A, and connected to the auxiliary member  8  via the two connecting parts  35  of the first connecting member  21  of the two connecting fittings  20 B. In this connecting work for connecting the door frame  2  to the auxiliary member  8 , the first connecting fitting  20 A inserted into the gap between the reinforcing member  7  and the side frame members  2 A and  2 B has a posture by which the inclination angle θ 1  made by the first connecting member  21  in the horizontal direction M as the direction of the gap between the reinforcing member  7  and the side frame members  2 A and  2 B and the inclination angle θ 2  made by the second connecting member  22  in the horizontal direction M are in opposite directions (see  FIG. 10 ). The door frame  2  is connected to the auxiliary member  8  so as to be vertically immobile. Also, in the abovementioned connecting work, the first connecting fitting  20 A inserted into the gap between the upper frame member  2 C and the auxiliary member  8  has a posture by which the inclination angle made by the first connecting member  21  in the vertical direction as the direction of the gap between the upper frame member  2 C and the reinforcing member  7  and the inclination angle made by the second connecting member  22  in the vertical direction are in opposite directions. Accordingly, the door frame  2  is connected to the auxiliary member  8  so as to be immobile in the horizontal direction as well. 
     Also, as shown in  FIGS. 16 and 17 , when the end portion (see  FIGS. 4 and 13 ), on the side of the auxiliary member  8 , of the first connecting member  21  of the first connecting fitting  20 A is coupled with the auxiliary member  8  by the two coupling fittings  25  inserted into the second holes  29  (see  FIGS. 7A, 7B, and 7D ) formed in the connecting parts  26  of the first connecting member  21 , the loads W from the coupling fittings  25  act on the end portions  26 A, on the side of the auxiliary member  8 , of the connecting parts  26  as explained above with reference to  FIGS. 8A, 8B, and 8C . This action of the loads W reduces or eliminates the torsion angle α having existed in the end portions  26 A on the side of the auxiliary member  8 , and generates the torsion angles β in the end portions  26 B, on the side of the door frame  2 , as the end portions opposite to the end portions  26 A as described previously. 
       FIG. 18  is an enlarged sectional view of the end portions  26 B, on the side of the door frame  2 , of the connecting parts  26  of the first connecting member  21 , and shows that the torsion angles β as described above form in the end portions  26 B. As shown in FIG.  18 , when the torsion angle β forms in the end portion  26 B, on the side of the door frame  2 , of the connecting part  26  of the first connecting member  21 , the torsion angle β is an angle inclining to the axial direction N of the central shaft  24 , so the hole  28  formed as an insertion portion in the end portion  26 B on the side of the door frame  2  in order to insert the central shaft  24  also inclines to the axial direction N of the central shaft  24 , and a corner  28 A of the hole  28  locks on the surface of the central shaft  24 . In other words, the central shaft  24  functions as a locked member on which the corner  28 A of the hole  28  locks. This locking of the hole  28  onto the locked member makes the first connecting fitting  20 A including the first connecting member  21  as a constituting member immobile in the thickness direction of the door frame  2  as the axial direction N of the central shaft  24 . Therefore, the door frame  2  is connected to the auxiliary member  8  as a skeleton-side construction material so as to be immobile in the thickness direction of the door frame  2 . 
     In particular, the central shaft  24  as the locked member of this embodiment is a male screw rod on the surface of which many projections and recesses are alternately formed in the axial direction by thread ridges and grooves, the corner  28 A of the hole  28  locks on the surface of the central shaft  24  more reliably as described above. Consequently, the door frame  2  can be connected to the auxiliary member  8  such that the door frame  2  is immobile more reliably in the thickness direction of the door frame  2 . 
     In this embodiment, the first and second connecting members  21  and  22  are coupled with the auxiliary member  8  by the coupling fittings  25  and  34  described above. The auxiliary member  8  is attached to the reinforcing member  7  by being set in a predetermined position in the thickness direction of the door frame  2  by the positioning member  10  shown in  FIG. 4 . Since, therefore, the corner  28 A of the hole  28  locks on the surface of the central shaft  24 , the door frame  2  is arranged by being set in the predetermined position in the thickness direction of the door frame  2 . 
     In this embodiment as described above, when the load W (see  FIGS. 8A and 8B ) from the coupling fitting  25  shown in  FIG. 4  acts on the end portion  26 A, on the side of the auxiliary member  8 , of each of the two connecting parts  26  of the first connecting member  21 , the bridge part  27  formed in the first connecting member  21  deforms, e.g., curves in a direction projecting to the outside of the first connecting member  21 , in the thickness direction of the bridge part  27 , and this forms the torsion angle β in the end portion  26 B, on the side of the door frame  2 , of the first connecting member  21 , as described with reference to  FIGS. 8A, 8B, and 8C . In this embodiment, the elongated hole  31  as a strength decreasing portion for decreasing the strength of the bridge part  27  is formed in the bridge part  27 . Accordingly, the load W causes deformation, e.g., curving of the bridge part  27  more reliably, and this forms the torsion angle β of the end portion  26 B on the side of the door  2 . 
     In the embodiment explained above, the end portions  26 A and  35 A, on the side of the auxiliary member  8 , of the two connecting parts  26  and  35  of the first and second connecting members  21  and  22  of the first connecting fitting  20 A are coupled with the auxiliary member  8  by the two coupling fittings  25  and the two coupling fittings  34 . As shown in  FIGS. 16 and 17 , the coupling fittings  25  and  34  are arranged on the opposite sides in the axial direction N of the central shaft  24  with respect to the first and second connecting members  21  and  22 , and couple the end portions  26 A and  35 A on the side of the auxiliary member  8  with the auxiliary member  8  in opposite directions in the axial direction N of the central shaft  24 . 
     On the other hand, another embodiment shown in  FIGS. 19 and 20  uses one coupling fitting  25  and another coupling fitting  50  different from the coupling fitting  25 , in order to couple end portions  26 A, on the side of an auxiliary member  8 , of two connecting parts  26  of a first connecting member  21  of a first connecting fitting  20 A, with the auxiliary member  8 . The coupling fittings  25  and  50  are arranged on the same side in an axial direction N of a central shaft  24  with respect to the first connecting member  21 , and in the same direction along the axial direction N. As shown in  FIG. 19 , the coupling fitting  50  is a coupling fitting that is inserted into a connecting part  26 D, of two connecting parts  26 D and  26 E, which is arranged on a side opposite to the side on which the coupling fittings  25  and  50  are arranged in the axial direction N of the central shaft  24 , and draws the connecting part  26 D toward the connecting part  26 E. In addition, one coupling fitting  34  and another coupling fitting  51  different from the coupling fitting  34  are used to couple end portions  35 A, on the side of the auxiliary member  8 , of two connecting parts  35  of a second connecting member  22 , with the auxiliary member  8 . The coupling fittings  34  and  51  are also arranged on the same side in the axial direction N of the central shaft  24  with respect to the second connecting member  22 , and in the same direction along the axial direction N. As shown in  FIG. 19 , the coupling fitting  51  is a coupling fitting that is inserted into a connecting part  35 D, of two connecting parts  35 , which is arranged on a side opposite to the side on which the coupling fittings  34  and  51  are arranged in the axial direction N of the central shaft  24 , and draws the connecting part  35 D toward a connecting part  35 E. 
     As shown in, e.g.,  FIG. 19 , the coupling fittings  50  and  51  are tapping screws including head portions  50 A and  51 A, small-diameter shaft portions  50 B and  51 B extending forward from the head portions  50 A and  51 A, and large-diameter male screw portions  50 C and  51 C extending forward from the small-diameter shaft portions  50 B and  51 B. The diameter of third holes  30  and  39  formed in the first and second connecting members  21  and  22  shown in  FIGS. 7A to 7D  and  FIG. 9B  is smaller than that of the large-diameter male screw portions  50 C and  51 C and larger than that of the small-diameter shaft portions  50 B and  51 B. 
     Accordingly, when the coupling fittings  50  and  51  are inserted into the third holes  30  and  39  of the connecting parts  26 E and  35 E, of the pair of connecting parts  26 D and  26 E and the pair of connecting parts  35 D and  35 E of the first and second connecting members  21  and  22 , and advanced by being rotated by using a tool, female screws are formed on the inner surfaces of the third holes  30  and  39  by the large-diameter male screw portions  50 C and  51 C. When the coupling fittings  50  and  51  are further advanced by being rotated by using the tool, the large-diameter male screw portions  50 C and  51 C form female screws in the third holes  30  and  39  of the connecting parts  26 D and  35 D on the side opposite to the side on which the coupling fittings  25 ,  34 ,  50 , and  51  are arranged in the axial direction N of the central shaft  24 . In this state, the small-diameter shaft portions  50 B and  51 B of the coupling fittings  50  and  51  have reached the third holes  30  and  39  of the connecting parts  26 E and  35 E on the same side as the side on which the coupling fittings  25 ,  34 ,  50 , and  51  are arranged, and the small-diameter shaft portions  50 B and  51 B are idling in the third holes  30  and  39 . On the other hand, the large-diameter male screw portions  50 C and  51 C draw the connecting parts  26 D and  35 D on the side opposite to the side on which the coupling fittings  25 ,  34 ,  50 , and  51  are arranged, toward the connecting parts  26 E and  35 E on the same side as the side on which the coupling fittings  25 ,  34 ,  50 , and  51  are arranged. 
     Consequently, of the end portions  26 A and  35 A, on the side of the auxiliary member  8 , of the two connecting parts  26  and the two connecting parts  35  of the first and second connecting members  21  and  22 , the end portions  26 A and  35 A on the side opposite to the side on which the coupling fittings  25 ,  34 ,  50 , and  51  are arranged are strongly pressed against the auxiliary member  8 . This sets the end portions  26 A and  35 A in the same state as that when they are coupled with the auxiliary member  8 . 
     In this embodiment, all the coupling fittings  25 ,  34 ,  50 , and  51  for coupling the end portions  26 A and  35 A, on the side of the auxiliary member  8 , of the connecting parts  26  and  35  of the first and second connecting members  21  and  22  of the first connecting fitting  20 A, with the auxiliary member  8  can be arranged on the same side in the axial direction N of the central shaft  24 . Therefore, the work for rotating and advancing the coupling fittings  25 ,  34 ,  50 , and  51  by using a tool can be performed by a worker on the same side in the axial direction N of the central shaft  24 . This makes it possible to facilitate the work, shorten the time of the work, and improve the workability of the work. 
     Note that in the embodiment shown in  FIGS. 19 and 20 , coupling fittings similar to the coupling fittings  25  and  50  are used to couple the end portions  26 A, on the side of the auxiliary member  8 , of the two connecting parts  26  of the first connecting member  21  forming the second connecting fitting  20 B (see  FIG. 3 ), with the auxiliary member  8 . 
     In this embodiment, the third holes  30  are formed in the two connecting parts  26 D and  26 E of the first connecting member  21  of the first and second connecting fittings  20 A and  20 B. Also, the third holes  39  are formed in the two connecting parts  35 D and  35 E of the second connecting member  22  of the first connecting fitting  20 A. Unlike the example shown in  FIG. 19 , therefore, the coupling fittings  25 ,  34 ,  50 , and  51  can also be arranged on the side of the connecting part  26 D of the first connecting member  21 , and on the side of the connecting part  35 D of the second connecting member  22 . Accordingly, the side on which the coupling fittings  25 ,  34 ,  50 , and  51  are arranged can freely be selected in accordance with the state of each installation site of the hinged door apparatus. In addition, the work for connecting the door frame  2  to the auxiliary member  8  of the wall  4  can be performed by arranging the coupling fittings  25 ,  34 ,  50 , and  51  on the same side in the thickness direction of the door frame  2 , for the first and second connecting fittings  20 A and  20 B to be arranged in the left and right side frame members  2 A and  2 B and the upper frame member  2 C of the door frame  2  shown in  FIG. 3 . 
       FIG. 21  is a plan sectional view showing the structure of a building or the like in which it is effective to arrange all the coupling fittings  25 ,  34 ,  50 , and  51  on the same side in the axial direction N of the central shaft  24  as explained with reference to  FIGS. 19 and 20 . In this structure, a fire door  61  that normally opens a doorway  60  inside a door frame  62  is openable/closable around a hinge  63  between the door frame  62  and a door case  65  for accommodating the closed fire door  61 . The door case  65  is connected to a back wall  64  having a large thickness. The first and second connecting fittings  20 A and  20 B and the coupling fittings  25 ,  34 ,  50 , and  51  shown in  FIGS. 19 and 20  are used to connect the door case  65  to the back wall  64 . Therefore, even in the structure in which one surface of the door case  65  in the thickness direction is covered with the wall  64 , the work for connecting the door case  65  to the back wall  64  can effectively be performed by using the first and second connecting fittings  20 A and  20 B and the coupling fittings  25 ,  34 ,  50 , and  51 . 
       FIGS. 22A and 22B  show a first connecting member  121  according to another embodiment.  FIGS. 22A and 22B  are respectively a side view and a rear view of the first connecting member  121 . Like the first connecting member  21  shown in  FIGS. 7A to 7D , the first connecting member  121  as a product obtained by punching and bending a metal plate includes two connecting parts  126  separated from each other in an axial direction N of a central shaft  24  and opposing each other, and a bridge part  127  is bridged between the end portions of the two connecting parts  126 , in the thickness direction of the whole first connecting member  121  on the side perpendicular to the axial direction N of the central shaft  24 . Therefore, the two connecting parts  126  are coupled with each other by the bridge part  127  for which the axial direction N of the central shaft  24  is the widthwise dimension. In addition, each connecting part  126  has a lengthwise dimension in a direction perpendicular to the axial direction N of the central shaft  24  and to the thickness direction of the whole first connecting member  121 , and this lengthwise dimension is a dimension by which two end portions  126 A and  126 B in the longitudinal direction reach a door frame  2  and an auxiliary member  8  as the skeleton of a wall  4 . 
     Also, in the first connecting member  121  of this embodiment, as shown in  FIG. 22A , the end portion  126 A on the side of the auxiliary member  8 , of the two end portions  126 A and  126 B in the longitudinal direction of each connecting part  126 , extends outward in the axial direction N of the central shaft  24  while extending outward in the longitudinal direction of the connecting part  126 . Therefore, the two end portions  126 A on the side of the auxiliary member  8  form an inverted V-shape that opens outward in the longitudinal direction of the connecting parts  126 . On the other hand, the end portion  126 B on the side of the door frame  2 , of the two end portions  126 A and  126 B in the longitudinal direction of each connecting part  126 , extends in the direction perpendicular to the axial direction N of the central shaft  24  while extending outward in the longitudinal direction of the connecting part  126 , so the two end portions  126 B of the door frame  2  are parallel to each other. 
     In addition, in each connecting part  126 , a large-diameter first hole  128  is formed as an insertion portion for inserting the central shaft  24  in the end portion  126 B on the side of the door frame  2 , and a small-diameter second hole  129  for inserting the coupling fitting  25  shown in  FIG. 4  is formed in the end portion  126 A on the side of the auxiliary member  8 . In each of the connecting parts  126 , a third hole  130  is also formed for inserting a coupling fitting  50  as the tapping screw explained with reference to  FIGS. 19 and 20  in the end portions  126 A which form the inverted V-shape that opens outward in the longitudinal direction of the connecting parts  126 . 
     Furthermore, the bridge part  127  include notches  131  and  132  cut inward in the longitudinal direction of the connecting parts  126  from end portions  127 A and  127 B of the bridge part  127  in the longitudinal direction of the connecting parts  126 . The notches  131  and  132  function as strength decreasing portions formed in the bridge part  127  in order to decrease the strength of the bridge part  127 . 
       FIG. 23  shows a state in which loads W in opposite directions in the axial direction N of the central shaft  24  act on the end portions  126 A on the side of the auxiliary member  8  in order to couple the end portions  126 A, on the side of the auxiliary member  8 , of the connecting parts  126  with the auxiliary member  8  by using the coupling fitting  25  shown in  FIG. 4  or the coupling fitting  50  shown in  FIGS. 19 and 20 . When the loads W act on the end portions  126 A on the side of the auxiliary member  8 , the end portions  126 A on the side of the auxiliary member  8  become parallel to each other, and the end portions  126 B of the door frame  2  form an inverted V-shape that opens outward in the longitudinal direction of the connecting parts  126  under the influence of the loads W. Consequently, the end portions  126 B of the door frame  2  and the first holes  128  formed in the end portions  126 B make inclination angles γ to the axial direction N of the central shaft  24 . 
     Consequently, similar to the state shown in  FIG. 18 , the corner of the first hole  128  locks on projections and recesses formed by thread ridges and grooves formed on the surface of the central shaft  24 , in the first connecting member  121  of this embodiment as well. This renders the first connecting member  121  immobile in the thickness direction of the door frame  2  as the axial direction N of the central shaft  24 . 
     Also, in the first connecting member  121  of this embodiment, the notches  131  and  132  are formed as the strength decreasing portions in the bridge part  127 . Therefore, when the above-described loads W act on the end portions  126 A on the side of the auxiliary member  8 , the end portions  126 B of the door frame  2  and the first holes  128  formed in the end portions  126 B make the inclination angles γ more reliably with respect to the axial direction N of the central shaft  24 . This makes it possible to more reliably cause the corners of the first holes  128  to lock on the projections and recesses formed by the thread ridges and grooves formed on the surface of the central shaft  24 . 
     The first connecting member  121  explained above can be used in the first and second connecting fittings  20 A and  20 B, instead of the first connecting member  21  described earlier. Accordingly, the parallelizing means  45  formed by the projecting piece  40  formed in the second connecting member  22  is also applicable to the first connecting member  121  shown in  FIGS. 22A, 22B, and 23 . 
     INDUSTRIAL APPLICABILITY 
     The present invention can be used to connect two construction materials spaced apart from each other, more specifically, to connect a construction material of a skeleton such as a wall to an apparatus-side construction material, e.g., an opening frame such as a door frame of a hinged door apparatus, a sliding door apparatus, or the like. 
     EXPLANATION OF THE REFERENCE NUMERALS AND SIGNS 
       1  . . . hinged door,  2  . . . door frame as construction material of hinged door apparatus,  2 A,  2 B . . . side frame member of door frame,  2 C . . . upper frame member of door frame,  4  . . . wall as skeleton,  7  . . . reinforcing member as skeleton-side construction material,  8  . . . auxiliary member as skeleton-side construction material,  20 ,  20 A,  20 B . . . connecting fitting,  21 ,  121  . . . first connecting member,  22  . . . second connecting member,  23  . . . bearing member,  24  . . . central shaft,  25 ,  34 ,  50 ,  51  . . . coupling fitting,  26 ,  126  . . . connecting part,  26 A,  126 A . . . auxiliary-member-side end portion,  26 B,  126 B . . . door-frame-side end portion,  27  . . . bridge part,  40  . . . projecting piece,  41  . . . notch as strength decreasing portion,  45  . . . parallelizing means, M . . . horizontal direction as direction of interval, N . . . axial direction, θ 1 , θ 2  . . . inclination angle