Abstract:
A fusion welding device including a first holder and a second holder where the respective holders are adapted to hold an end portion of a first work and a second work, respectively, such that the works are moveable in a longitudinal direction; a heater, operable to heat the first and second works; two movers adapted to move the first and second holders close to or apart from each other; and a third mover adapted to move the first and second holders in synchronization with each other in a direction along the first and second faces. The first and second holders are moved by the third mover where the first and second faces are in contact with each other, whereby end faces of the end portions of the first and second works are pressed to each other.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Japanese Application No. 2007-063167, filed Mar. 13, 2007, which is hereby incorporated herein in its entirety by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a fusion welding device of works for joining by fusion welding the works such as resin frame members which form a resin frame of a resin sash, a resin frame of a resin screen, etc., and an assembling apparatus of the resin frame for assembling the resin frame such as a resin window frame, a resin screen frame, etc. using the fusion welding device. 
     A window frame is assembled by connecting four pieces of frame members in a shape of bar (an upper frame, a lower frame, and vertical frames at right and left sides) into a rectangular shape. A sash is formed by fitting a screen to this window frame. 
     A screen frame is assembled by connecting four pieces of frame members in a shape of bar (an upper frame, a lower frame, and vertical frames at right and left sides) into a rectangular shape. 
     A screen is formed by fitting a glass panel or the like to this screen frame. 
     As the aforesaid window frame and screen frame, a metal frame employing frame members formed of metal (hereinafter referred to as metal frame members), and a resin frame employing frame members formed of resin (hereinafter referred to as resin frame members) have been known. 
     In case of the aforesaid metal frame, the frame is assembled by connecting end portions of the metal frame members to each other with small screws or the like. 
     On the other hand, in case of the aforesaid resin frame, the frame is assembled by cutting end portions of the resin frame members at 45 degree, and joining them by fusion welding. 
     As described above, in order to join the end portions of the resin frame members by fusion welding, the end portions to be joined are fused with heat of a heater, as a first step, and then, the end portions are joined to each other by abutting and pressing their end faces which have been fused to each other, and thereafter, cooled, whereby the fused parts are hardened to make an integral member. 
     In case where the resin frame members are joined by fusion welding as described above, the end portions of the resin frame members are pressed when they are fused by the heater, or when the fused end portions are joined. Consequently, the end portions protrude outward, and fins may occur. 
     Generally, these fins are removed by cutting with a cutter or the like after the end portions have been joined. 
     Such being the circumstances, a process for removing the fins is required, and therefore, assembling cost for the resin frame is increased. 
     Moreover, those regions where the fins have been removed by cutting may be sometimes different in color from other regions, and hence, an outer appearance is deteriorated. 
     In view of the above, a related-art fusion welding device for preventing occurrence of fins in the regions which have been joined by fusion welding (a heat-fusion joining and working device) is disclosed in JP-A-2001-150552. 
     This related-art fusion welding device includes a pair of work grasping units which grasp the work to move it between a waiting position and a heat fusing position, and a heater unit. A mold assembly of the work grasping unit includes a fixed side mold assembly and a movable side mold assembly. The movable side mold assembly is movable toward the fixed side mold assembly when pressed at a time of joining. Because end portions of the work are fused and joined by fusion welding in a state where the end portions have entered in the movable side mold assembly, the end portions will not protrude outward, and occurrence of fins can be prevented. 
     In the above described related-art fusion welding device, when the end portions of the works are fused and joined by fusion welding, fusion and fusion welding are carried out, by moving the movable side mold assembly toward the fixed side mold assembly. However, because the movable side mold assembly is supported by a resilient member such as a spring, and the mold assembly is closed with a spring force, there is such anxiety that the mold may be opened with pressure of fins which apt to protrude outward, and the fins may occur. 
     Moreover, in order to press the end portions of the two works, the works are moved in respective longitudinal directions thereof together with the respective work grasping units (the mold assembly) in a state where the end portions of the works are grasped by the respective work grasping units, whereby the end portions come close to each other to be pressed. 
     For this reason, in order to assemble a frame, fusion welding operation must be conducted at every corner of the frame, and hence, assembling work of the frame requires a considerable time. 
     For example, in case where the frame in a rectangular shape is assembled, fusion welding operations must be sequentially conducted four times at the four corners of the frame, and the assembling work requires a lot of time. 
     SUMMARY 
     It is therefore an object of the invention to provide a fusion welding device in which occurrence of fins can be reliably prevented when end portions of works are joined by fusion welding, and moreover, end portions of a plurality of works are joined by fusion welding at the same time in all corner parts of a frame, when the frame is formed by joining the end portions of the works by fusion welding, and an assembling apparatus of a resin frame. 
     In order to achieve the object, according to the invention, there is provided a fusion welding device, comprising: 
     a first holder, having a first face, and adapted to hold at least an outer peripheral face of an end portion of a first work in a state where the first work is movable in a longitudinal direction thereof; 
     a second holder, having a second face opposed to the first face, and adapted to hold at least an outer peripheral face of an end portion of a second work in a state where the second work is movable in a longitudinal direction thereof; 
     a heater, operable to heat the first work and the second work; 
     a first mover and a second mover, adapted to move the first holder and the second holder in such directions that the first face and the second face come close to or apart from each other; and 
     a third mover, adapted to move the first holder and the second holder in synchronization with each other in a direction along the first face and the second face, 
     wherein the first holder and the second holder are moved by the third mover in a state where the first face and the second face are in contact with each other, whereby end faces of the end portions of the first and second works are pressed to each other in the longitudinal directions thereof in the first and second holders. 
     The fusion welding device may further include a fourth mover. The heater may have a third face and a fourth face. When the heater is disposed in a first position, the third face can be contacted with the first face of the first holder and the fourth face can be contacted with the second face of the second holder. When the heater is disposed in a second position, the third face cannot be contacted with the first face and the fourth face cannot be contacted with the second face. The fourth mover may move the heater between the first position and the second position. When the first and second holders are moved by the third mover, the heater may be moved together with the first and second holders. 
     The first holder, the second holder, the heater, the first mover, the second mover, and the fourth mover may be provided on a moving body. The third mover may include a base member and the moving body mounted on the base member so as to move in the direction along the first face and the second face. 
     According to the invention, there is provided an assembling apparatus, incorporating a plurality of the fusion welding device respectively mounted to corner parts of a resin frame to be assembled. 
     According to the invention, there is also provided an assembling apparatus, comprising: 
     a body, including a first body, a second body attached to the first body so as to move in a lateral direction, and a third body attached to the first body, the second body provided with a first fusion welding device and a second fusion welding device which can move in a vertical direction, the third body provided with a third fusion welding device and a fourth fusion welding device which can move in a vertical direction, wherein 
     each of the first, second, third and fourth fusion welding devices is provided with a first and second holders adapted to hold at least outer peripheral faces of end portions of resin frame members in a state where the frame members are movable in longitudinal directions thereof, a heater operable to heat the frame members, a first and second mover operable to move the first and second holders in such directions that contact faces of the first and second holders, which are opposed to each other, come close to or apart from each other, 
     the first, second, third and fourth fusion welding devices are positioned in respective corner parts of a frame, and both of the end portions of each of the frame members are respectively held by the first and second holders of adjacent two of the first, second, third and fourth fusion welding devices, and 
     the first, second, third and fourth fusion welding devices are moved, in a state where the contact firsts are in contact with each other, in such directions that distances of adjacent two of the first, second, third and fourth fusion welding devices are reduced, so that the end portions of the frame members are joined by fusion welding. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic front view of an assembling apparatus of a resin frame in an embodiment according to the invention. 
         FIGS. 2A and 2B  are views for explaining an angle of inclination of end faces of works. 
         FIG. 3  is an enlarged front view showing a fusion welding device. 
         FIGS. 4A and 4B  are views for explaining a holding unit. 
         FIG. 5  is a sectional view taken along a line A-A in  FIG. 3 . 
         FIG. 6  is a sectional view taken along a line B-B in  FIG. 3 . 
         FIG. 7  is a sectional view taken along a line C-C in  FIG. 3 . 
         FIG. 8  is a view for explaining operation for joining the works by fusion welding. 
         FIG. 9  is a view for explaining the operation for joining the works by fusion welding. 
         FIG. 10  is a view for explaining the operation for joining the works by fusion welding. 
         FIG. 11  is a view for explaining the operation for joining the works by fusion welding. 
         FIG. 12  is a view for explaining assembling operation of a resin frame. 
         FIG. 13  is a front view of an assembling apparatus of a resin frame in another example of the first embodiment according to the invention. 
         FIG. 14  is a front view of an assembling apparatus of a resin frame in a second embodiment according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIG. 1  shows an assembling apparatus of a resin frame in which a plurality of fusion welding devices  2  are mounted on a body  1  to assemble a frame  3 . 
     Each of the fusion welding devices  2  joins end portions in a longitudinal direction of two works at a determined angle by fusion welding, and provided at every corner of the frame  3 . 
     In this embodiment, the fusion welding device  2  joins the end portions of the two works at 90 degree, and the frame  3  has a rectangular shape. 
     The body  1  includes a laterally directed first body  1   a  which is longer in a lateral direction (a direction X), a second body  1   b  which is longer in a vertical direction (a direction Y) and moves in the lateral direction along this first body  1   a , and a third body  1   c  which is longer in the vertical direction and fixed to the first body  1   a.    
     For example, a pair of first guide rails  4  are provided on the first body  1   a  which is laterally longer, and the second body  1   b  which is vertically longer is mounted on these first guide rails  4  so as to move in the lateral direction. A laterally directed first cylinder  5  is mounted across the second body  1   b  and the first body  1   a , so that the second body  1   b  can move in the lateral direction by extending and contracting the first cylinder  5 . 
     The fusion welding device  2  includes a first fusion welding device  2   a  which is attached to a lower part of the second body  1   b , a second fusion welding device  2   b  which is attached to an upper part of the second body  1   b  so as to move in the vertical direction, a third fusion welding device  2   c  which is attached to a lower part of the third body  1   c , and a fourth fusion welding device  2   d  which is attached to an upper part of the third body  1   c  so as to move in the vertical direction. 
     The first to fourth fusion welding devices  2   a  to  2   d  are respectively positioned in the four corner parts of the frame  3  in the rectangular shape. 
     Second guide rails  6  are respectively provided in the upper parts of the second and third bodies  1   b ,  1   c  in the vertical direction. The second and fourth fusion welding devices  2   b ,  2   d  are respectively mounted so as to move along the second guide rails  6 . Vertically directed second cylinders  7  are mounted across the second and third bodies  1   b ,  1   c  and the second and fourth fusion welding devices  2   b ,  2   d , so that the second and fourth fusion welding devices  2   b ,  2   d  can move in the vertical direction by extending and contracting the second cylinders  7 . When the second and fourth fusion welding devices  2   b ,  2   d  move, they come close to or move apart from the first and third fusion welding devices  2   b ,  2   c.    
     The first and second moving units are not limited to the cylinder, but may be a rack-and-pinion, or a feed screw and a nut. 
     In this manner, by moving the second body  1   b  in the lateral direction, the first and second fusion welding devices  2   a ,  2   b  move in the lateral direction, and it is possible to assemble the frames  3  having different sizes in the lateral direction. 
     Moreover, by moving the second and fourth fusion welding devices  2   b ,  2   d  with respect to the second body  1   b  and the third body  1   c  in the vertical direction, it is possible to assemble the frames  3  having different sizes in the vertical direction. 
     Further, by moving the second body  1   b  in the lateral direction, and by moving the second and fourth fusion welding devices  2   b ,  2   d  in the vertical direction, it is possible to assemble the frames  3  having different sizes both in the lateral direction and in the vertical direction. 
     As shown in  FIGS. 2A and 2B , end faces  8   a  in the longitudinal direction of works  8  (resin frame members which are components of the frame  3 ) to be joined by fusion welding with the fusion welding device  2  are inclined with respect to a right angle with the longitudinal direction. 
     An angle of inclination θ 1  of the end faces  8   a  of the works  8  is a half of a corner angleθ 2  of the frame  3 . 
     For example, in case where the corner angle θ 2  of the frame  3  is 90 degree, as shown in  FIG. 2A , the angle of inclination θ 1  is 45 degree. In case where the corner angle θ 2  is 60 degree, as shown in  FIG. 2B , the angle of inclination θ 1  is 30 degree. 
     Then, the fusion welding device  2  ( 2   a ,  2   b ,  2   c ,  2   d ) will be described referring to  FIGS. 3 to 7 . 
     The fusion welding device  2  includes a first holding unit  10 , a second holding unit  20 , and a heating unit  30 , as shown in  FIG. 3 . 
     The first holding unit  10  and the second holding unit  20  can move along outer peripheral faces of the works  8  in the longitudinal directions thereof and hold the end portions of outer peripheral faces with almost no clearance. The first holding unit  10  and the second holding unit  20  respectively have contact faces  11  and  21  opposed to each other. Expression “with almost no clearance” means both a case where the contact face is in contact with the outer peripheral face of the work  8 , and a case where the contact face is slightly apart from the outer peripheral face of the work  8 . 
     For example, the first holding unit  10  and the second holding unit  20  have respective holding spaces  12 ,  22  which have substantially the same shape as a cross sectional shape of the work  8  (a sectional shape at a right angle with respect to the longitudinal direction). These holding spaces  12 ,  22  are open on end faces  13 ,  23  at the opposite side to the contact faces  11 ,  21 . 
     Specifically, as shown in  FIG. 4A , the holding space  12  or  22  is formed by combining a recess  14   a ,  24   a  of a lower mold  14 ,  24  and a recess  15   a ,  25   a  of an upper mold  15 ,  25 . The outer peripheral face  8   b  of the work  8  is held on an inner peripheral face of the holding space  12 ,  22  with almost no clearance, but can move in the holding space  12 ,  22 . 
     As shown in  FIG. 4B , by separating the upper mold  15 ,  25  from the lower mold  14 ,  24 , it is possible to set or remove the work  8  in or from the recess  14   a ,  24   a  in the lower mold  14 ,  24 . 
     The contact faces  11 ,  21  of the first and second holding units  10 ,  20  which are opposed to each other have the same angle as the angle of inclination of the end faces  8   a  of the works  8 . When the works  8  are held by the first and second holding units  10 ,  20 , the contact faces  11 ,  21  and the end faces  8   a  of the works  8  can be continued to be flush with each other. 
     The first and second holding units  10 ,  20  respectively move in parallel with each other between a first position where the contact faces  11  and  21  are in contact with each other, and second and third positions where the contact faces  11 ,  21  are separated from each other. 
     For example, the first and second holding units  10 ,  20  are respectively moved by first and second parallel moving units  40 ,  50  in parallel with each other. These movements by the first and second parallel moving units  40 ,  50  are effected in a direction perpendicular to the longitudinal direction of the works  8  which are respectively held by the holding units. 
     Moreover, the first and second holding units  10 ,  20  are respectively moved synchronously in a direction along their contact faces  11  and  21 . 
     For example, the first and second holding units  10 ,  20  are moved synchronously in the direction along their contact faces  11  and  21  by a synchronous moving unit  60 . In short, both the first and second holding units  10 ,  20  are moved at the same time. 
     The aforesaid heating unit  30  has a first heating face  31  which is contacted with the contact face  11  of the first holding unit  10 , and a second heating face  32  which is contacted with the contact face  21  of the second holding unit  20 . These first and second heating faces  31 ,  32  are flat. 
     The heating unit  30  is moved between a heating position which is located between the first and second holding units  10  and  20  (between the contact faces  11  and  21 ), and a retreating position where it has retreated from the position between the first and second holding units  10 ,  20 . 
     For example, the heating unit  30  is moved by a moving unit  70  between the heating position and the retreating position. 
     In other words, the heating position is a position where the first heating face  31  can be contacted with the contact face  11  of the first holding unit  10  and the second heating face  32  can be contacted with the contact face  21  of the second holding unit  20 , when the heating unit  30  is disposed in the position. On the other hand, the retreating position is a position where the first heating face  31  cannot be contacted with the contact face  11  of the first holding unit  10  and the second heating face  32  cannot be contacted with the contact face  21  of the second holding unit  20 , when the heating unit  30  is disposed in the position. 
     Referring to  FIGS. 5 and 6 , a specific embodiment of the aforesaid first and second parallel moving units  40 ,  50  will be described. 
     A first rail  41  and a second rail  51  are provided on a moving body  80 . Then, a first guide  42  and a second guide  52  which are respectively provided on the first and second holding units  10 ,  20  (the lower molds  14 ,  24 ) are slidably engaged with the first and second rails  41 ,  51  so that the first and second holding units  10 ,  20  can move in the directions perpendicular to the longitudinal directions of the works  8  which are held. 
     For this reason, when the holding units move between the first position and the second and third positions, they can move to determined positions, even though the works  8  are movably held by the holding units. 
     First and second electric motors  43 ,  53  are mounted on the moving body  80 . Then, feed screw rods  44 ,  54  which are rotated by the first and second motors  43 ,  53  are screwed with nuts  45 ,  55  which are fitted to the first and second holding units  10 ,  20  so as to rotate but not to move. When the first and second electric motors  43 ,  53  are driven, the first and second holding units  10 ,  20  are moved. In this manner, the first and second parallel moving units  40 ,  50  are constructed. 
     The first and second parallel moving units  40 ,  50  are driven to move the first and second holding units  10 ,  20  for the same distance, and controlled so that the first and second holding units  10 ,  20  may be at symmetrical positions with respect to a corner part of the frame  3 . 
     For example, the first electric motor  43  and the second electric motor  53  are synchronously controlled so that the first and second holding units  10 ,  20  can move for the same distance. 
     The first and second parallel moving units  40 ,  50  are not limited to those as described above, but a cylinder or a rack-and-pinion may be employed as the parallel moving units. 
     Referring to  FIG. 7 , a specific embodiment of the synchronous moving unit  60  will be described. 
     Guides  61  provided on the moving body  80  are slidably engaged with rails  62  provided on a base member  81 . Then, an electric motor  63  is mounted on the base member  81 , and a feed screw rod  64  rotated by the electric motor  63  is screwed with a nut  65  which is fitted to the moving body  80  so as to rotate but not to move. When the electric motor  63  is driven, the moving body  80  is moved with respect to the base member  81 . In this manner, the synchronous moving unit  60  is constructed. This movement by the synchronous moving unit  60  is called as synchronous movement, because the first and second holding units  10 ,  20  are moved at the same time. 
     In the above described structure, because it would be sufficient to drive and control the only one electric motor  63 , the structure is simple and can be easily controlled. 
     The synchronous moving unit  60  is not limited to the structure as described above, but a cylinder or a rack-and-pinion may be employed for moving the moving body  80 . 
     Moreover, the first and second holding units  10 ,  20  may be moved by separate moving units, provided that the separate moving units are synchronously driven. 
     A specific embodiment of the moving unit  70  will be described. 
     A rail  71  is mounted on the aforesaid moving body  80 , and a guide  72  engaged with this rail  71  is fitted to the heating unit  30 . 
     A cylinder  74  is mounted on the moving body  80  by way of a bracket  73 , and a piston rod  75  of the cylinder  74  is coupled to the heating unit  30 . By extending and contracting the piston rod  75  of the cylinder  74 , the heating unit  30  moves between the heating position and the retreating position. In this manner, the moving unit  70  is constructed. 
     As this moving unit  70 , a cylinder, and a rack-and-pinion may be employed. 
     As shown in  FIG. 1 , the base member  81  of the first fusion welding device  2   a  is attached to the lower part of the second body  1   b , and the base member  81  of the second fusion welding device  2   b  is attached to the upper part of the second body  1   b  so as to move in the vertical direction. 
     The base member  81  of the third fusion welding device  2   c  is attached to the lower part of the third body  1   c , and the base member  81  of the fourth fusion welding device  2   d  is attached to the upper part of the third body  1   c  so as to move in the vertical direction. 
     Then, the moving body  80  of the first fusion welding device  2   a  and the moving body  80  of the fourth fusion welding device  2   d  move in the respective directions opposed to each other. The moving body  80  of the second fusion welding device  2   b  and the moving body  80  of the third fusion welding device  2   c  move in the respective directions opposed to each other. 
     Specifically, the first and fourth fusion welding devices  2   a ,  2   d  are positioned in the two corner parts of the frame  3  which are opposed to each other on a diagonal line, while the second and third fusion welding devices  2   b ,  2   c  are positioned in the remaining two corner parts of the frame  3  which are opposed to each other on a diagonal line. 
     Then, operation of the fusion welding device  2  for joining the two works  8  to each other by fusion welding will be described. 
     As shown in  FIG. 8 , the first and second holding units  10 ,  20  are positioned in the third position where their contact faces  11 ,  21  are remarkably separated, and the end portions of the works  8  are respectively held in the holding spaces  12 ,  22 . 
     In this state, the heating unit  30  is moved to the heating position, as shown by a phantom line in  FIG. 8 . 
     As shown in  FIG. 9 , the first and second holding units  10 ,  20  are moved, in parallel, to the second position where the contact faces  11 ,  21  are separated, and the contact faces  11 ,  21  are brought into contact with the first and second heating faces  31 ,  32  of the heating unit  30 . 
     In this state, the heating unit  30  is heated, and the moving body  80  is moved in a direction of an arrow mark a. 
     With this movement, the first and second holding units  10 ,  20  synchronously move in the direction along their contact faces  11 ,  21  (the direction of the arrow mark a), and at the same time, the heating unit  30  also moves. Accordingly, the works  8  move with respect to the first and second holding units  10 ,  20  in their longitudinal directions opposed to each other, so as to project from the contact faces  11 ,  21 . 
     Specifically, the end portion of the work  8  at an opposite side to the end portion which is held by one of the fusion welding devices  2   a  to  2   d  tends to move so as to project from the contact faces  11 ,  21  of the first and second holding units  10 ,  20  of the other fusion welding device  2   a  to  2   d , whereby the end faces  8   a  of the works  8  are strongly pressed to the first and second heating faces  31 ,  32  of the heating unit  30 , and thus, the end portions of the works  8  are fused. 
     In this manner, the end portions of the works  8  are pressed onto the heating unit  30  (the first and second heating faces  31 ,  32 ) in a state held in the holding spaces  12 ,  22  of the first and second holding units  10 ,  20 , thereby to be fused. Therefore, the end portions of the works  8  will not protrude outward, when they are fused, and fins will not occur. 
     In this embodiment, the works  8  are hollow-shaped, and are fused in such a manner that their end portions enter into the hollow spaces. Therefore, a region to be fused is elongated, and it is possible to enlarge the region to be joined by fusion welding. 
     Moreover, when the end portions of the works  8  are fused, as described above, the works  8  do not move in their longitudinal directions in a state held in the holding spaces. Therefore, in case of assembling the frame  3 , it is possible to fuse the end portions of the works  8  at the same time in the respective corner parts. 
     Thereafter, the first and second holding units  10 ,  20  are moved, in parallel, to the above described third position, and the heating unit  30  is moved to the retreating position. 
     In this state, the first and second holding units  10 ,  20  are moved to the first position where the contact faces  11 ,  21  are in contact, as shown in  FIG. 11 , whereby the contact faces  11  and  12  are brought into contact with each other. 
     In this state, the moving body  80  is further moved in the direction of the arrow mark a, in the same manner as described above, whereby the end faces  8   a  of the works  8  are pressed to each other and joined together. 
     As described above, the end faces  8   a  of the works  8  are pressed to each other and joined by fusion welding, in a state where the end portions are held in the holding spaces  12 ,  22  of the first and second holding units  10 ,  20 . Therefore, fins will not occur in the joined region. 
     Moreover, the works  8  are moved in the respective longitudinal directions in a state opposed to each other, when the first and second holding units  10 ,  20  are moved by the synchronous moving unit  60 , and when the end faces  8   a  of the works  8  are in contact with each other, the works  8  do not move in the longitudinal directions in a state held in the holding spaces. Therefore, in case of assembling the frame  3 , it is possible to join the respective corner parts at the same time. 
     In the above described embodiment, the first and second holding units  10 ,  20  and the heating unit  30  are mounted on the moving body  80  so that the heating unit  30  may move at the same time with the first and second holding units  10 ,  20 , when the end portions of the works  8  are fused. However, the structure is not limited to the above described. In case where the first and second holding units  10 ,  20  are moved by separate moving units as described above, it is possible to drive and control the moving unit  70  synchronously with the separate moving units or to move the heating unit  30  by an external force. 
     In short, it would be sufficient that the heating unit  30  moves with the first and second holding units  10 ,  20 , when the first and second holding units synchronously move. 
     Moreover, a manner of fusing the end portions of the works  8  is not limited to the above-described manner. For example, it is possible to fuse the end portions of the works  8  by butting the heating unit  30  against the end portions. 
     Then, operation for assembling a resin frame, employing the assembling apparatus of the resin frame as shown in  FIG. 1  will be described. The work  8  is described as a resin frame member  8 . 
     As shown in  FIG. 12 , both end portions in a longitudinal direction of a first resin frame member  8  are set and held between the holding space  22  of the second holding unit  20  of the first fusion welding device  2   a  and the holding space  12  of the first holding unit  10  of the second fusion welding device  2   b , as described above, and both end portions in a longitudinal direction of a second resin frame member  8  are set and held between the holding space  12  of the first holding unit  10  of the first fusion welding device  2   a  and the holding space  22  of the second holding unit  20  of the third fusion welding device  2   c.    
     In the same manner, both end portions in a longitudinal direction of a third resin frame member  8  are set and held between the holding space  12  of the first holding unit  10  of the third fusion welding device  2   c  and the holding space  22  of the second holding unit  20  of the fourth fusion welding device  2   d , and both end portions in a longitudinal direction of a fourth resin frame member  8  are set and held between the holding space  12  of the first holding unit  10  of the forth fusion welding device  2   d  and the holding space  22  of the second holding unit  20  of the second fusion welding device  2   b.    
     In short, the first fusion welding device  2   a  is adjacent to the second fusion welding device  2   b  and the third fusion welding device  2   c , while the fourth fusion welding device  2   d  is adjacent to the second fusion welding device  2   b  and the third fusion welding device  2   c . Both the end portions in the longitudinal direction of the resin frame member  8  are held between the holding spaces  12  and  22  of the first and second holding units  10 ,  20  of the adjacent fusion welding devices. 
     In this state, the first to fourth fusion welding devices  2   a  to  2   d  are operated at the same time, in the same manner as shown in  FIGS. 8 to 11 , and the end portions of the resin frame members  8  are joined by fusion welding in the corner parts as shown in  FIGS. 2A and 2B . In other words, the first to fourth fusion welding devices  2   a  to  2   d  are moved, in a state where the contact faces  11 ,  21  are in contact with each other, in such directions that distances of adjacent two of the first to fourth fusion welding devices  2   a  to  2   d  are reduced, so that the end portions of the frame members  8  are joined by fusion welding. 
     In this case, the end faces  8   a  of the four resin frame members  8  are pressed to each other in the respective corner parts, and hence, the end faces  8   a  can be effectively joined by fusion welding. 
     In the above described embodiment, the frame  3  in a rectangular shape is assembled. However, the frame  3  is not limited to the rectangular shape. It is possible to assemble the frame  3  of a desired shape, such as a triangular shape, a pentagonal shape. 
     For example, as shown in  FIG. 13 , it is possible to assemble the frame  3  in a triangular shape by fusion welding, by providing the first, second and third fusion welding devices  2   a ,  2   b ,  2   c  in the respective corner parts of the frame  3  in a triangular shape. 
     In this case, the corner angle θ 2  is 60 degree, and so, the angle of inclination of the end faces  8   a  of the works  8  is 30 degree. 
     Then, a second embodiment of the assembling apparatus of the resin frame will be described referring to  FIG. 14 . 
     In the same manner as the aforesaid body  1  as shown in  FIG. 1 , the body  1  includes the first body  1   a , the second body  1   b , and the third body  1   c . The second body  1   b  moves in a lateral direction with respect to the first body  1   a.    
     The first and second fusion welding devices  2   a ,  2   b  are mounted on the second body  1   b , in the same manner as in the apparatus as shown in  FIG. 1 . 
     The third and fourth fusion welding devices  2   c ,  2   d  are mounted on the third body  1   c , in the same manner as in the apparatus as shown in  FIG. 1 . 
     The first to fourth fusion welding devices  2   a  to  2   d  have the same structure as the fusion welding device  2  as shown in  FIG. 3 , except that they are not provided with the synchronous moving unit  60  in the fusion welding device  2  as shown in  FIG. 3 . 
     In short, each of the first to fourth fusion welding devices  2   a  to  2   d  includes the first and second holding units  10 ,  20 , the heating unit  30 , the first and second parallel moving units  40 ,  50 , and the moving unit  70 . These units are mounted on the first moving body  80 . 
     In this embodiment, in the second and fourth fusion welding devices  2   b ,  2   d , the moving body  80  is attached to the second guide rail  6  so as to move up and down, and the first and third fusion welding devices  2   a ,  2   c  are attached to the respective lower ends of the second and third bodies  1   b ,  1   c . When the second body  1   b  moves along the direction X so as to come close to or apart from the third body  1   c , the first fusion welding device  2   a  moves close to or apart from the third fusion welding device  2   c.    
     Then, operation for assembling the frame  3  will be described. It is to be noted that the work  8  is described as the resin frame member  8 . 
     In the same manner as described above, both the end portions in the longitudinal direction of the resin frame member  8  are set between the holding spaces  12 ,  22  of the first and second holding units  10 ,  20  of the fusion welding devices which are adjacent to each other, and held so as to move in the longitudinal direction. 
     In the above described state, the first and second holding units  10 ,  20  of the respective fusion welding devices  2  are positioned in the third position where they are separated, and the heating unit  30  is moved to the heating position. 
     Then, the first and second holding units  10 ,  20  are moved to the second position, and the contact faces  11 ,  21  are brought into contact with the heating unit  30  (the first and second heating faces  31 ,  32 ). 
     In this state, the second body  1   b  is moved in the lateral direction toward the third body  1   c , and the second and fourth fusion welding devices  2   b ,  2   d  (the first moving body  80 ) are respectively moved in the vertical direction toward the first and third fusion welding devices  2   a ,  2   c.    
     In this manner, a distance between the first fusion welding device  2   a  and the third fusion welding device  2   c , and a distance between the second fusion welding device  2   b  and the fourth fusion welding device  2   d  in the lateral direction are reduced. At the same time, a distance between the first fusion welding device  2   a  and the second fusion welding device  2   b , and a distance between the third fusion welding device  2   c  and the fourth fusion welding device  2   d  in the vertical direction are reduced. 
     In other words, the frame  3  in a rectangular shape is reduced in size keeping similarity, and the end faces  8   a  of the adjacent resin frame members  8  are pressed to the heating unit  30  thereby to be fused. 
     Because this pressing force acts as a counteraction on the end faces  8   a  at the opposite side, the end faces  8   a  at the opposite side are also pressed to the heating unit  30  to be fused. 
     Thereafter, the first and second holding units  10 ,  20  are moved to the third position where they are separated, and the heating unit  30  is moved to the retreating position. 
     Then, the first and second holding units  10 ,  20  are moved to the first position to bring the contact faces  11 ,  21  into contact. 
     In this state, the second body  1   b , and the second and fourth fusion welding devices  2   b ,  2   d  are moved in the same manner as described above, whereby the end faces  8   a  of the resin frame members  8  are pressed to each other thereby to be joined by fusion welding. 
     In the above described first and second embodiments, the second body  1   b  moves so as to approach and separate from the third body  1   c . Alternatively, it is possible to move the third body  1   c  or to move both the second and third bodies. 
     According to an aspect of the present invention, the end portions of the works  8  which have been fused with the heating unit  30  are held by the first and second holding units  10 ,  20 , and the first and second holding units  10 ,  20  are synchronously moved by the synchronous moving unit  60  in a state where the contact faces  11 ,  21  are in contact with each other, whereby the end faces  8   a  of the works  8  are pressed in the longitudinal directions thereof inside the first and second holding units  10 ,  20  to be joined. 
     Therefore, occurrence of fins can be reliably prevented, when the end portions of the works  8  are joined by fusion welding. 
     Moreover, there is no necessity of moving the works  8  in the longitudinal directions, because the works  8  are joined by moving the first and second holding units  10 ,  20 . Therefore, when the end portions of a plurality of the works  8  are joined by fusion welding to form the frame, it is possible to join the end portions of the works by fusion welding at the same time in the respective corner parts of the frame. 
     According to an aspect of the present invention, the first and second holding units  10 ,  20  are moved by the synchronous moving unit  60  in a state where the contact faces  11 ,  21  of the first and second holding units are in contact with the first and second heating faces  31 ,  32  of the heating unit  30 , whereby the end faces  8   a  of the works  8  are pressed to the first and second heating faces  31 ,  32  of the heating unit, and the end portions of the works  8  are fused inside the first and second holding units  10 ,  20 . 
     Therefore, when the end portions of the works  8  are fused, fins will not occur. 
     According to an aspect of the present invention, the moving body  80  is moved with respect to the base member  81 , whereby the first and second holding units  10 ,  20  are synchronously moved, and the heating unit  30  is also moved at the same time. 
     Therefore, the synchronous moving unit  60  is simple in structure, and can be easily operated and controlled. 
     According to an aspect of the present invention, the resin frame can be assembled by joining the end portions of the resin frame member by fusion welding, and fins will not occur at a time of joining by fusion welding. 
     Moreover, because the end portions of the resin frame members  8  can be joined by fusion welding at the same time in the respective corner parts of the resin frame, it is possible to assemble the resin frame efficiently in a short time.