Abstract:
A screen extending frame including cut grooves formed from an inner side to an outer side thereof, or from the outer side to the inner side, or in both directions of joints of the screen extending frame, which is constituted by connecting four frame members in a rectangle shape. The cut grooves enable the joints to deform. The four frame members are individual bodies that are joined by corner members, and connecting portions are inclined with respect to the longitudinal direction of the frame members. Gaps are created in the connections. Elastic elements can be placed at the connections of the four frame members. Alternatively, the joint portions are orthogonal to the longitudinal direction, and elastic elements are placed at the joints.

Description:
[0001]    This application is a divisional of application Ser. No. 13/522,606, which is the National Stage of International Application No. PCT/JP2011/051722, filed Jan. 28, 2011. 
     
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
       [0002]    The present invention relates to a screen extending frame in which a screen for screen printing in a sheet shape or a mesh shape is extended and is mounted on a screen extending jig for adjusting tension of the screen in regard to manufacturing of printed circuit boards. 
       2. Description of the Related Art 
       [0003]    A printed circuit board in the subtractive process that is generally used in electric/electronic devices is configured to be formed with a conductive pattern by removing unnecessary portions of copper foil stuck to an insulating substrate, and active and passive elements are fixed to the conductive pattern by means of soldering, or the like. 
         [0004]    In the subtractive process, after holes are made on an insulating substrate, such as a glass epoxy plate, to which copper foil is stuck, unnecessary portions of the copper foil is removed by printing and etching, and then a conductive pattern is formed. When soldering is performed by a reflow method, solder cream is printed further on necessary portions. 
         [0005]    In screen printing, a screen board, which is a mesh-like sheet woven with a metal or a resin or a sheet made of a metal or a resin, is used by forming holes of image thereon and by extending the sheet in a frame with uniform tension, not making crinkles. 
         [0006]    With regard to a printed pattern, a metal mask where through holes are formed on a metal thin plate made of stainless steel or the like is extended in a screen extending frame with tension, ink is transferred onto the insulating substrate via the through holes using a squeegee, and thereby, a conductive pattern or a solder pattern is formed thereon. 
         [0007]    At this moment, if the screen board does not come into tight contact with the object to be printed, the ink runs over from a gap causing bleeding, which results in inaccurate printing. 
         [0008]    A planar shape is ideal for the object to be printed, but there may be warping or waviness thereon in some cases, and a material with flexibility is selected for the squeegee in order to keep the screen board in tight contact with the printed object, and the extending tension of the screen is not so tensed. 
         [0009]    However, since the screen is required to be as strongly extended as possible, a rigid and sturdy screen frame is prepared, the sheet is intensively pulled from four directions, and extended using a stretching property of the sheet material and using a repulsive force thereof. 
         [0010]    When a metal mesh is used, it can be extended since the mesh does not have a high stretching property but has a little. When a metal sheet with no stretching property is used, the sheet can be extended by connecting the outer circumference of the centered metal sheet to a resin sheet having the stretching property. 
         [0011]    The screen is used as attached to the screen extending frame. If there has slack, the location of the printed pattern is deviated or the pattern is warped when the screen is rubbed by the squeegee. In order to prevent such a situation, it is necessary to always give a certain degree of tension to the screen by exerting a tensile force thereto when printing is performed. 
         [0012]    For a screen extending frame, there are a tension fixed frame of which the size is fixed so as to maintain the tensile force of the screen constant, and a tension variable frame of which the size varies so as to be able to change the tensile force of the screen. Since both frames are required to have strength that gives a tensile force to the screen, the frames have to be robust and large. In addition, the tension variable frame of which the size varies includes a variable mechanism, and accordingly, the frame costs higher. 
         [0013]    The screen needs to be separated from the circuit board to be printed before and after printing, and to be brought into tight contact with the circuit board when printing is performed using a squeegee. For this reason, the screen is required to have the stretching property. However, since the metal mask does not have the stretching property, it is, in general, stuck to a mesh made of polyester strings, stainless steel strings, or the like and is used as a screen. There may be a case where a metal mask is used as it is, and in that case, any extending and reducing mechanism is provided in the mounting portion of the metal mask or in the screen extending frame. 
         [0014]    A screen using a mesh is attached to the screen extending frame mostly by using an adhesive agent, and such the screen is kept attached to the screen extending frame so long as the screen is necessary. For this reason, when being not in use, the heavy and bulky screen has to be stored or transported. 
         [0015]    There is a screen extending frame in a configuration where the end part of the screen using a mesh is attached thereto by means of winding, clamping, or the like. In a case of such the screen extending frame, it is possible to remove the screen from the screen extending frame for storage or transportation when the screen is not in use, but it is not easy to store or transport the screen without damaging the printing patterns that are precisely formed thereon as the screen is thin. 
         [0016]    Taking the circumstances into consideration, the present inventor has proposed in Patent Application No. 2002-556010 (refer to Publication No. WO2002/055304) a device for screen printing in which a screen extending frame is divided into a screen extending jig having a tensile force adjusting mechanism and a screen extending frame in a simple structure without the tensile force adjusting mechanism, which is provided with an engagement mechanism to connect the jig and the frame with each other, and thereby, the screen is attached to the screen extending frame. 
         [0017]    The screen printing device is described referring to  FIG. 1 . 
         [0018]    In  FIG. 1(A) , the reference numeral  1  is the screen extending jig, and the screen extending frame  2  having engagement grooves  4  is mounted on the screen extending jig  1 . To the screen extending frame  2 , a screen  3  is attached, which is a sheet that is a metal plate or a resin plate with conductive patterns formed by through holes, or is a mesh stuck a sheet with conductive patterns formed by through holes, not shown in the drawing, thereto. By extending and reducing the screen extending jig  1 , an appropriate tensile force is exerted on the screen  3 . 
         [0019]    The screen extending frame  2  is constituted by joining four plate-shaped, or rectangular tube-shaped frame members together by means of welding, or the like. 
         [0020]    In description hereinafter, on frame members constituting the screen extending frame, the length in the longitudinal direction of each frame member represents the “length”, the length from the outside to the inside thereof represents the “width”, and the length between a face to which the sheet is attached and a face to which the sheet is not attached represents the “thickness”. 
         [0021]      FIGS. 1(B)  and (C) illustrate mounting the screen extending frame  2  on the screen extending jig  1 .  FIG. 1(B)  shows the state of the screen extending frame  2  before being mounted on the screen extending jig  1 , and  FIG. 1(C)  shows the state of the screen extending frame  2  being mounted on the screen extending jig  1 . 
         [0022]    The engagement grooves  4  are formed on the mounting sides of the screen extending frame  2  along the longitudinal direction of the screen extending jig, and engagement elements  5  are formed on the mounting sides of the screen extending jig  1  along the longitudinal direction of the screen extending jig. 
         [0023]    The tensile force to the screen  3  is adjusted by extending or reducing the screen extending jig  1  in the arrow directions shown in the drawing where the engagement elements  5  are kept engaged with the engagement grooves  4 . 
         [0024]    Conductive patterns are formed using the screen by transferring ink with a squeegee not shown in the drawing via through holes. 
         [0025]    When the screen is not in use and to be stored, it is most ideal to store the screen extending frame  2  being mounted on the screen extending jig  1 , but since the screen extending jig  1  having an extending and reducing mechanism is not only expensive but also bulky, storage or transportation of the screen extending frame  2  attached with the screen being mounted on the screen extending jig  1  is not efficient. 
         [0026]    The screen is attached to the screen extending frame  2  by fixing means such as an adhesive agent, that is mounted on the screen extending jig  1 , and the tensile force is exerted thereon by the screen extending jig  1 . When not being mounted on the screen extending jig  1 , slack or the like occurs which may cause the screen deformation. It is, therefore, desirable for the screen to have a certain degree of tension even being attached only to the screen extending frame  2 . 
         [0027]    A screen printing device using a screen extending frame, in which the screen is attached to a screen extending frame, the screen extending frame is mounted on the screen extending jig, and the tension of the screen is adjusted by changing the size of the screen extending jig, is disclosed in Japanese Patent Laid-Open Publication Nos. 2006-212955, 2006-44180 and 2008-1010 by the present inventor, in addition to the publication WO2002/055304. Furthermore, Japanese Patent Laid-Open Publication No. 2000-15777 also describes a screen printing device using a screen extending frame. 
       RELATED ART REFERENCES 
       [0028]    Document 1: JP-A-2000-15777 
         [0029]    Document 2: WO2002/055304 
         [0030]    Document 3: JP-A-2006-44180 
       SUMMARY OF THE INVENTION 
       [0031]    These screen extending frames of the prior art can exert a certain degree of tension on the screen by exerting the tensile force to the screen when the screen is fixed thereto, but since the frame has no function of exerting the tensile force, it is not possible to exert a sufficient tension. For this reason, if the screen extending frame is removed from the bulky screen extending jig in order to effectively use the expensive screen extending frame to save space for storage and transportation, there is a concern that slack occurs in the screen, resulting in deformation of the screen. 
         [0032]    The invention according to the present application aims to provide a screen extending frame that can prevent the above circumstance. 
         [0033]    The configuration overview of the invention for achieving the above aim is as follows. 
         [0034]    According to the invention provided in the present application, cut grooves are formed in the inner sides and/or outer sides of connections orthogonally connecting four frame members constituting a screen extending frame so that the angles of the connections change, allowing the frame members inwardly or outwardly change in shape, and accordingly, the size of the screen extending frame variable. 
         [0035]    The screen extending frame mounted with an elastic element is reduced by a jig such as a screen extending jig having an extending and reducing function, a screen is attached to the screen extending frame in that state, and when fixing work, such as adhesion, is completed, setting the extending or reducing degree of the screen extending jig to be optimum, then screen printing is performed. 
         [0036]    It is possible to extend and reduce the screen extending frame with an extending function by setting the function of extending the screen extending frame in a screen printing device. 
         [0037]    In addition, in order to achieve the object of the invention, a gap or an elastic element is provided in each joint of the four frame members so as to give an extending force to an end of a frame side in each connections of the frame members, whereby flexibility is given to the extending frame, according to the invention of the present application. 
         [0038]    For the elastic element to be provided, a solid elastic element such as natural rubber or synthetic rubber, or a non-solid spring such as a plate spring or a coil spring can be used, and it is also possible to further provide an elastic element in the gap in the joint. 
         [0039]    The screen extending frame mounted with the elastic element is reduced by a jig such as a screen extending jig having an extending and reducing function, a screen is attached to the screen extending frame in that state, and when fixing work, such as adhesion, is completed, setting the extending or reducing degree of the screen extending jig to be optimum, then screen printing is performed. 
         [0040]    It is possible to reduce the screen extending frame with a reducing function by setting the function of reducing the screen extending frame in a screen printing device. 
         [0041]    Specific configurations for achieving the above objective are described in the following (1) to (38). 
         [0042]    (1) A screen extending frame in a rectangular shape which is constituted by four frame members having the square-shape cross-section, and is used in such a way that a screen is attached to one face thereof, and the other face thereof is mounted on a screen extending jig having an extending and reducing function, in which joint of the four frame members have flexibility and elasticity. 
         [0043]    (2) The screen extending frame according to (1) above, in which the four frame members connect in the joint, and the joint have flexibility and elasticity. 
         [0044]    (3) The screen extending frame according to (2) above, in which the four frame members are solid bodies. 
         [0045]    (4) The screen extending frame according to (3) above, in which cut grooves are formed in the width direction of the joints. 
         [0046]    (5) The screen extending frame according to (3) above, in which cut grooves are formed in the direction connecting the outer corner and the inner corner each of the joints. 
         [0047]    (6) The screen extending frame according to (3) above, in which grooves are formed on both faces of the joints in the thickness direction. 
         [0048]    (7) The screen extending frame according to (6) above, in which the grooves in the thickness direction are formed in the width direction of the frame members. 
         [0049]    (8) The screen extending frame according to (6) above, in which the grooves in the thickness direction are formed in the direction connecting the outer corner and the inner corner each of the joints. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0050]      FIGS. 1(A)-1(C)  illustrate a screen extending jig and a screen extending frame of the related art. 
           [0051]      FIGS. 2(A)-2(C)  are illustrative configuration diagrams of a screen extending frame according to Embodiment 1. 
           [0052]      FIG. 3  is an illustrative function diagram of the screen extending frame according to Embodiment 1. 
           [0053]      FIGS. 4(A)-4(C)  are illustrative configuration diagrams of a screen extending frame according to Embodiment 2. 
           [0054]      FIG. 5  is an illustrative function diagram of the screen extending frame according to Embodiment 2. 
           [0055]      FIGS. 6(A)-6(C)  are illustrative configuration diagrams of a screen extending frame according to Embodiment 3. 
           [0056]      FIGS. 7(A)-7(C)  are illustrative configuration diagrams of a screen extending frame according to Embodiment 4. 
           [0057]      FIGS. 8(A)-8(C)  are illustrative configuration diagrams of a screen extending frame according to Embodiment 5. 
           [0058]      FIGS. 9(A)-9(C)  are illustrative configuration diagrams of a screen extending frame according to Embodiment 6. 
           [0059]      FIGS. 10(A)-10(C)  are illustrative configuration diagrams of a screen extending frame according to Embodiment 7. 
           [0060]      FIGS. 11(A)-11(C)  are illustrative configuration diagrams of a screen extending frame according to Embodiment 8. 
           [0061]      FIGS. 12  (A)- 12 (C) are illustrative configuration diagrams of a screen extending frame according to Embodiment 9. 
           [0062]      FIGS. 13(A)-13(C)  are illustrative configuration diagrams of a screen extending frame according to Embodiment 10. 
           [0063]      FIGS. 14(A)-14(C)  are illustrative configuration diagrams of a screen extending frame according to Embodiment 11. 
           [0064]      FIGS. 15(A)-15(C)  are illustrative configuration diagrams of a screen extending frame according to Embodiment 12. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0065]    Hereinafter, embodiments of the invention according to the present application are described with reference to the drawings. 
         [0066]    A screen extending frame to be shown in embodiments is a screen extending frame in a rectangular shape and used, when a screen is attached thereto, by being mounted on a screen extending jig having an extending and reducing function. It is constituted by a first frame member and a third frame member that are arranged in parallel and have the same length, and a second frame member and a fourth frame member that are arranged in parallel and have the same length, the cross-sections of the first, the second, the third and the fourth frame members are square, one faces of the first, the second, the third and the fourth frame members are plane to which the screen is attached. A rectangular screen extending frame is formed by connecting the first and the second frame members, the second and the third frame members, the third and the fourth frame members, and the fourth and the first frame members, and the corners of the screen extending frame are configured so as to have flexibility and elasticity. 
         [0067]    In screen extending frames of Embodiments 1 to 12 shown in  FIGS. 4 to 15 , four frame members constituting the frame each are formed in a single unit. 
         [0068]    In Embodiments 1 to 12 described with reference to  FIGS. 4 to 15 , flexibility of the joints of the solid screen extending frames is obtained through cut grooves formed in the joints of the frame members in the width direction. 
       EMBODIMENT 1 
       [0069]      FIG. 2  shows a configuration of Embodiment 1, and  FIG. 3  illustrates the function of Embodiment 1. 
         [0070]    In  FIG. 2 , (A) is an overall view of a screen extending frame  30 , (B) is an enlarged exploded view of a portion indicated by the dashed circle B in (A), and (C) is a cross-sectional view of the portion indicated by the dashed line C in (B). 
         [0071]    As shown in  FIG. 2(A)  of the overall view and  FIG. 2(B)  of the enlarged exploded view, the screen extending frame  30  is assembled with four frame members  31   a,    31   b,    31   c,  and  31   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0072]    On the four frame members  31   a,    31   b,    31   c,  and  31   d,  engagement grooves  32   a,    32   b,    32   c,  and  32   d  with which engagement elements formed in a screen extending jig are engaged each are formed. 
         [0073]    A cut groove  33   a  in the inner side of the joint of the frame members  31   a  and  31   b  from the inner corner to the outer corner; a cut groove  33   b  in the inner side of the joint of the frame members  31   b  and  31   c  from the inner corner to the outer corner; a cut groove  33   c  in the inner side of the joint of the frame members  31   c  and  31   d  from the inner corner to the outer corner; and a cut groove  33   d  in the inner side of the joint of the frame members  31   d  and  31   a  from the inner corner to the outer corner are formed. 
         [0074]    All of the four frame members  31   a,    31   b,    31   c,  and  31   d  have the same cross-sectional shape, the engagement groove  32   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  31   a  as shown by the cross-section in  FIG. 4(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0075]    When the screen is attached to the screen extending frame  30 , the engagement elements of the extending jig are engaged with the engagement grooves  32   a,    32   b,    32   c,  and  32   d,  and the extending jig is extended and reduced, the screen extending frame  30  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0076]    The function of the screen extending frame  30  is described referring to  FIG. 3  The screen extending frame  30  configured by the joined four frame members  31   a,    31   b,    31   c,  and  31   d  is pressed in the directions of the black arrows using a tool such as the screen extending jig, a clamp, a vise, or the like, not shown in the drawing. For this reason, as the open ends of the cut grooves  33   a,    33   b,    33   c,  and  33   d  reduce, the frame members  31   a,    31   b,    31   c,  and  31   d  inwardly bend, and the screen extending frame  10  is reduced, and resulted a reduced screen extending frame  30 ′ constituted by curved frame members  31   a ′,  31   b ′,  31   c ′, and  31   d′.    
         [0077]    Then, the screen is fixed to the reduced screen extending frame  30 ′ by means of adhesion, or the like. 
         [0078]    In the state where fixation of the screen to the reduced screen extending frame  30 ′ is completed, the pressing force to the reduced screen extending frame  30 ′ exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0079]    When the pressing force to the reduced screen extending frame  30 ′ is released, the curved frame members  31   a′ ,  31   b′ ,  31   c′ , and  31   d′  that inwardly bend will return to the shape of the state of not being compressed, and as the open ends of the cut grooves  33   a′   33   b′ ,  33   c′ , and  33   d′  open widely, the reduced screen extending frame  30 ′ extends, and accordingly, a tensile force is exerted on the screen attached to the screen extending frame thus extended. 
         [0080]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
         [0081]    As is obvious from the above description of the function, the screen extending frame gives a tensile force on the screen even when the extending jig is not used, and therefore, it is possible to perform screen printing only with the screen extending frame alone without using the screen extending jig. 
         [0082]    Insertion of a solid elastic element such as natural rubber or synthetic rubber or a non-solid spring such as a plate spring or a coil spring into the cut grooves  33   a,    33   b,    33   c,  and  33   d  enables protection of the open ends and supplementation of elasticity. 
       EMBODIMENT 2 
       [0083]    Embodiment 2 obtained by modifying Embodiment 1 is shown in  FIG. 4 , and the function of Embodiment 2 is described referring to  FIG. 5 . 
         [0084]    In the drawing, (A) is an overall view of a screen extending frame  40 , (B) is an enlarged exploded view of a portion indicated by a dashed circle B in (A), and (C) is a cross-sectional view of a portion indicated by a dashed line C in (B). 
         [0085]    As shown in  FIG. 5(A)  of the overall view and  FIG. 5(B)  of the enlarged exploded view, the screen extending frame  40  is assembled with four frame members  41   a,    41   b,    41   c,  and  41   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0086]    On the four frame members  41   a,    41   b,    41   c,  and  41   d,  engagement grooves  42   a,    42   b,    42   c,  and  42   d  with which engagement elements formed in screen extending jig are engaged each are formed. 
         [0087]    An inclined cut groove  43   a  in the inner side of the joint of the frame members  41   a  and  41   b  from the inner corner to the outer corner; a narrow inclined cut groove  43   b  in the inner side of the joint of the frame members  41   b  and  41   c  from the inner corner to the outer corner; a narrow inclined cut groove  43   c  in the inner side of the joint of the frame members  41   c  and  41   d  from the inner corner to the outer corner; and a narrow inclined cut groove  43   d  in the inner side of the joint of the frame members  41   d  and  41   a  from the inner corner to the outer angle are formed. 
         [0088]    Furthermore, there are formed on the frame member  41   a  a narrow cut groove  44   ab  from the outer side orthogonally toward the inner side at the joint with the frame member  41   b  and a narrow cut groove  44   ad  from the outer side orthogonally toward the inner side at the joint thereof with the frame member  41   d;  on the frame member  41   b  a narrow cut groove  44   ba  from the outer side orthogonally toward the inner side at the joint with the frame member  41   a  and a narrow cut groove  44   bc  from the outer side orthogonally toward the inner side at the joint thereof with the frame member  41   c;  on the frame member  41   c  a narrow cut groove  44   cb  from the outer side orthogonally toward the inner side at the joint with the frame member  41   b  and a narrow cut groove  44   cd  from the outer side orthogonally toward the inner side at the joint thereof with the frame member  41   d;  and on the frame member  41   d  a narrow cut groove  44   dc  from the outer side orthogonally toward the inner side at the joint with the frame member  41   c  and a narrow cut groove  44   da  from the outer side orthogonally toward the inner side at the joint thereof with the frame member  41   a.    
         [0089]    All of the four frame members  41   a,    41   b,    41   c,  and  41   d  have the same cross-sectional shape, the engagement groove  42   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  41   a  as shown by the cross-section in  FIG. 6(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0090]    When the screen is attached to the screen extending frame  40 , the engagement elements of the extending jig are engaged with the engagement grooves  42   a,    42   b,    42   c,  and  42   d,  and the extending jig is extended and reduced, the screen extending frame  40  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0091]    The function of the screen extending frame  40  is described referring to  FIG. 5 . In the drawing, the screen extending frame  40  configured by the joined four frame members  41   a,    41   b,    41   c,  and  41   d  is pressed in the directions of the black arrows using a tool such as the screen extending jig, a clamp, a vise, or the like, not shown in the drawing. For this reason, as the open ends of the cut grooves  43   a,    43   b,    43   c,  and  43   d  are reduced, resulting in reduced open ends  43   a′ ,  43   b′ ,  43   c′ ,  43   d′ ,  43   ab′ ,  43   ba′ ,  43   bc′ ,  43   cb′ ,  43   cd′ ,  43   dc′ ,  43   da′ , and  43   ad′ , the frame members  41   a,    41   b,    41   c,  and  41   d  inwardly shift, causing the screen extending frame  40  to be reduced, and resulted a reduced screen extending frame  40 ′ constituted by reduced frame members  41   a′ ,  41   b′ ,  41   c′ , and  41   d′.    
         [0092]    The screen is, then, fixed to the screen extending frame  40 ′ by means of adhesion, or the like. 
         [0093]    In the state where fixation of the screen to the reduced screen extending frame  40 ′ is completed, the pressing force to the reduced screen extending frame  40 ′ exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0094]    When the pressing force to the reduced screen extending frame  40 ′ is released, the frame members  41   a′ ,  41   b′ ,  41   c′ , and  41   d′  that inwardly shift will return to the shape of the state not being compressed, and as the open ends of the cut grooves  43   a′ ,  43   b′ ,  43   c′ ,  43   d′ ,  43   ab′ ,  43   ba′ ,  43   bc′ ,  43   cb′ ,  43   cd′ ,  43   dc′ ,  43   da′ , and  43   ad′  open widely, the reduced screen extending frame  40 ′ extends, and a tensile force is exerted on the screen fixed to the screen extending frame thus extended. 
         [0095]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
         [0096]    As is obvious from the above description of the function, the screen extending frame gives the tensile force on the screen even when the extending jig is not used, and therefore, it is possible to perform screen printing only with the screen extending frame alone without using the screen extending jig. 
         [0097]    Insertion of a solid elastic element such as natural rubber or synthetic rubber or a non-solid spring such as a plate spring or a coil spring into the cut grooves  43   a,    43   b,    43   c,    43   d,    43   ab,    43   ba,    43   bc,    43   cb,    43   cd,    43   dc,    43   da,  and  43   ad  enables protection of the open ends and supplementation of elasticity. 
       EMBODIMENT 3 
       [0098]    Embodiment 3 that is another Embodiment obtained by modifying Embodiment 1 is shown in  FIG. 6 . 
         [0099]    In the drawing, (A) is an overall view of a screen extending frame  50 , (B) is an enlarged exploded view of a portion indicated by a dashed circle B in (A), and (C) is a cross-sectional view of a portion indicated by a dashed line C in (B). 
         [0100]    As shown in  FIG. 8(A)  of the overall view and  FIG. 8(B)  of the enlarged exploded view, the screen extending frame  50  is assembled with four frame members  51   a,    51   b,    51   c,  and  51   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0101]    On the four frame members  51   a,    51   b,    51   c,  and  51   d,  engagement grooves  52   a,    52   b,    52   c,  and  52   d  with which engagement elements formed in a screen extending jig are engaged each are formed. 
         [0102]    There are formed a narrow inclined cut groove  53   a  in the inner side of the joint of the frame members  51   a  and  51   b  from the inner corner to the outer corner; a narrow inclined cut groove  53   b  in the inner side of the joint of the frame members  51   b  and  51   c  from the inner corner to the outer corner; a narrow inclined cut groove  53   c  in the inner side of the joint of the frame members  51   c  and  51   d  from the inner corner to the outer corner; and a narrow inclined cut groove  53   d  in the inner side of the joint of the frame members  51   d  and  51   a  from the inner angle to the outer angle. 
         [0103]    Furthermore, there are formed on the frame member  51   a  a cut groove  54   ab  that is orthogonal to the outer side from the inner side of the joint with the frame member  51   b  and a narrow cut groove  54   ad  that is orthogonal to the outer side from the inner side of the joint thereof with the frame member  51   d;  on the frame member  51   b  a narrow cut groove  54   ba  that is orthogonal to the outer side from the inner side of the joint with the frame member  51   a  and a narrow cut groove  54   bc  that is orthogonal to the outer side from the inner side of the joint thereof with the frame member  51   c;  on the frame member  51   c  a narrow cut groove  54   cb  that is orthogonal to the outer side from the inner side of the joint with the frame member  51   b  and a narrow cut groove  54   cd  that is orthogonal to the outer side from the inner side of the joint thereof with the frame member  51   d;  and on the frame member  51   d  a narrow cut groove  54   dc  that is orthogonal to the outer side from the inner side of the joint with the frame member  51   c  and a narrow cut groove  54   da  that is orthogonal to the outer side from the inner side of the joint thereof with the frame member  51   a.    
         [0104]    All of the four frame members  51   a,    51   b,    51   c,  and  51   d  have the same cross-sectional shape, the engagement groove  52   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  51   a  as shown by the cross-section in  FIG. 8(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0105]    When the screen is attached to the screen extending frame  50 , the engagement elements of the extending jig are engaged with the engagement grooves  52   a,    52   b,    52   c,  and  52   d,  and the extending jig is extended and reduced, the screen extending frame  50  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0106]    When the screen extending frame  50  configured by combining the four frame members  51   a,    51   b,    51   c,  and  51   d  is pressed in the inward direction using a tool such as the screen extending jig, a clamp, a vise, or the like, the open ends of the cut grooves  53   a,    54   ab,    54   ba,    53   b,    54   bc,    54   cb,    53   c,    54   cd,    54   dc,    53   d,    54   da,  and  54   ad  that are formed inner side are reduced, the frame members  51   a,    51   b,    51   c,  and  51   d  inwardly bend, and accordingly, the screen extending frame  50  is reduced. 
         [0107]    The screen is, then, fixed to the screen extending frame by means of adhesion, or the like. 
         [0108]    In the state where fixation of the screen to the reduced screen extending frame is completed, the pressing force to the reduced screen extending frame exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0109]    As a result of releasing the pressing force to the reduced screen extending frame, the frame members that inwardly bend will return to the shape of the state not being compressed, and as the open ends of the cut grooves  53   a,    54   ab,    54   ba,    53   b,    54   bc,    54   cb,    53   c,    54   cd,    54   dc,    53   d,    54   da,  and  54   ad  open widely, thereby the frame members  51   a,    51   b,    51   c,  and  51   d  outwardly extend, causing the screen extending frame  50  to extend, and a tensile force is exerted on the screen attached to the extended screen extending frame. 
         [0110]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
         [0111]    Insertion of a solid elastic element such as natural rubber or synthetic rubber or a non-solid spring such as a plate spring or a coil spring into the cut grooves  53   a,    53   b,    53   c,    53   d,    54   ab,    54   ba,    54   bc,    54   cb,    54   cd,    54   dc,    54   da,  and  54   ad  enables protection of the open ends and supplementation of elasticity. 
       EMBODIMENT 4 
       [0112]    Embodiment 4 that is another Embodiment obtained by modifying Embodiment 1 is shown in  FIG. 7 . 
         [0113]    Description of the function corresponding to that of  FIG. 3  or  FIG. 5  is omitted. In  FIG. 9 , (A) is an overall view of a screen extending frame  60 , (B) is an enlarged exploded view of a portion indicated by a dashed circle B in (A), and (C) is a cross-sectional view of a portion indicated by a dashed line C in (B). 
         [0114]    As shown in  FIG. 9(A)  of the overall view and  FIG. 9(B)  of the enlarged exploded view, the screen extending frame  60  is assembled with four frame members  61   a,    61   b,    61   c,  and  61   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0115]    On the four frame members  61   a,    61   b,    61   c,  and  61   d,  engagement grooves  62   a,    62   b,    62   c,  and  62   d  with which engagement elements formed in a screen extending jig are engaged each are formed. 
         [0116]    There are formed a narrow inclined cut groove  63   a  in the outer side of the joint of the frame members  61   a  and  61   b  from the outer corner to the inner corner; a narrow inclined cut groove  63   b  in the outer side of the joint of the frame members  61   b  and  61   c  from the outer corner to the inner corner; a narrow inclined cut groove  63   c  in the outer side of the joint of the frame members  61   c  and  61   d  from the outer corner to the inner corner; and a narrow inclined cut groove  63   d  in the outer side of the joint of the frame members  61   d  and  61   a  from the outer corner to the inner corner. 
         [0117]    Furthermore, there are formed on the frame member  61   a  a narrow inclined cut groove  64   ab  from the outer side toward the inner side of the joint with the frame member  61   b  and a narrow inclined cut groove  64   ad  from the outer side toward the inner side of the joint thereof with the frame member  61   d;  on the frame member  61   b  a narrow inclined cut groove  64   ba  from the outer side toward the inner side of the joint with the frame member  61   a  and a narrow inclined cut groove  64   bc  from the outer side toward the inner side of the joint thereof with the frame member  61   c;  on the frame member  61   c  a narrow inclined cut groove  64   cb  from the outer side toward the inner side of the joint with the frame member  61   b  and a narrow inclined cut groove  64   cd  from the outer side toward the inner side of the joint thereof with the frame member  61   d;  and on the frame member  61   d  a narrow inclined cut groove  64   dc  from the outer side toward the inner side of the joint with the frame member  61   c  and a narrow inclined cut groove  64   da  from the outer side toward the inner side of the joint thereof with the frame member  61   a.    
         [0118]    All of the four frame members  61   a,    61   b,    61   c,  and  61   d  have the same cross-sectional shape, the engagement groove  62   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  61   a  as shown by the cross-section in  FIG. 9(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0119]    When the screen is attached to the screen extending frame  60 , the engagement elements of the extending jig are engaged with the engagement grooves  62   a,    62   b,    62   c,  and  62   d,  and the extending jig is extended and reduced, the screen extending frame  60  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0120]    When the screen extending frame  60  configured by combining the four frame members  61   a,    61   b,    61   c,  and  61   d  is pressed in the inward direction using a tool such as the screen extending jig, a clamp, a vise, or the like, the open ends of the cut grooves  63   a,    63   b,    63   c,  and  63   d  that are formed in the inner side are reduced, the open ends of the cut grooves  64   ab,    64   ba,    64   bc,    64   cb,    64   cd,    64   dc,    64   da,  and  64   ad  that are formed in the outer side open widely, and accordingly, the frame members  61   a,    61   b,    61   c,  and  61   d  inwardly bend, causing the screen extending frame  60  to be reduced. 
         [0121]    The screen is, then, fixed to the reduced screen extending frame by means of adhesion, or the like. 
         [0122]    In the state where fixation of the screen to the reduced screen extending frame is completed, the pressing force to the reduced screen extending frame exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0123]    As a result of releasing the pressing force to the reduced screen extending frame, the frame members that inwardly bend will all return to the shape of the state not being compressed, and as the open ends of the cut grooves  63   a,    63   b,    63   c,  and  63   d  that are formed in the inner side are widely open and the open ends of the cut grooves  44   ab,    64   ba,    64   bc,    64   cb,    64   cd,    64   dc,    64   da,  and  64   ad  that are formed in the outer side are reduced, thereby the frame members  61   a,    61   b,    61   c,  and  61   d  extend to the outer side to extend the screen extending frame  60 , and therefore, a tensile force is exerted on the screen attached to the extended screen extending frame. 
         [0124]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
         [0125]    Insertion of a solid elastic element such as natural rubber or synthetic rubber or a non-solid spring such as a plate spring or a coil spring into the cut grooves  63   a,    63   b,    63   c,    63   d,    64   ab,    64   ba,    64   bc,    64   cb,    64   cd,    64   dc,    64   da,  and  64   ad  enables protection of the open ends and supplementation of elasticity. 
       EMBODIMENT 5 
       [0126]    Embodiment 5 that is another example obtained by modifying Embodiment 1 is shown in  FIG. 8 . 
         [0127]    Description of the function corresponding to that of  FIG. 3  or  FIG. 5  is omitted. In  FIG. 8 , (A) is an overall view of a screen extending frame  70 , (B) is an enlarged exploded view of a portion indicated by a dashed circle B in (A), and (C) is a cross-sectional view of a portion indicated by a dashed line C in (B). 
         [0128]    As shown in  FIG. 10(A)  of the overall view and  FIG. 10(B)  of the enlarged exploded view, the screen extending frame  70  is assembled with four frame members  71   a,    71   b,    71   c,  and  71   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0129]    On the four frame members  71   a,    71   b,    71   c,  and  71   d,  engagement grooves  72   a,    72   b,    72   c,  and  72   d  with which engagement elements formed in a screen extending jig are engaged each are formed. 
         [0130]    There are formed a narrow inclined cut groove  73  a in the outer side of the joint of the frame members  71   a  and  71   b  from the outer corner to the inner corner; a narrow inclined cut groove  73   b  in the outer side of the joint of the frame members  71   b  and  71   c  from the outer corner to the inner corner; a narrow inclined cut groove  73   c  in the outer side of the joint of the frame members  71   c  and  71   d  from the outer corner to the inner corner; and a narrow inclined cut groove  73   d  in the outer side of the joint of the frame members  71   d  and  71   a  from the outer corner to the inner corner. 
         [0131]    Furthermore, there are formed on the frame member  71   a  a narrow inclined cut groove  74   ab  from the inner side toward the outer side of the joint with the frame member  71   b  and a narrow inclined cut groove  74   ad  from the inner side toward the outer side of the joint thereof with the frame member  71   d;  on the frame member  71   b  a narrow inclined cut groove  74   ba  from the inner side toward the outer side of the joint with the frame member  71   a  and a narrow inclined cut groove  74   bc  from the inner side toward the outer side of the joint thereof with the frame member  71   c;  on the frame member  71   c  a narrow inclined cut groove  74   cb  from the inner side toward the outer side of the joint with the frame member  71   b  and a narrow inclined cut groove  74   cd  from the inner side toward the outer side of the joint thereof with the frame member  71   d;  and on the frame member  71   d  a narrow inclined cut groove  74   dc  from the inner side toward the outer side of the joint with the frame member  71   c  and a narrow inclined cut groove  74   da  from the inner side toward the outer side of the joint thereof with the frame member  71   a.    
         [0132]    All of the four frame members  71   a,    71   b,    71   c,  and  71   d  have the same cross-sectional shape, the engagement groove  72   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  71   a  as shown by the cross-section in  FIG. 10(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0133]    When the screen is attached to the screen extending frame  70 , the engagement elements of the extending jig are engaged with the engagement grooves  72   a,    72   b,    72   c,  and  72   d,  and the extending jig is extended and reduced, the screen extending frame  70  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0134]    When the screen extending frame  70  configured by combining the four frame members  71   a,    71   b,    71   c,  and  71   d  is pressed in the inward direction using a tool such as the screen extending jig, a clamp, a vise, or the like, the open ends of the cut grooves  73   a,    73   b,    73   c,    73   d,    74   ab,    74   ba,    74   bc,    74   cb,    74   cd,    74   dc,    74   da,  and  74   ad  are reduced, and accordingly, the frame members  71   a,    71   b,    71   c,  and  71   d  inwardly bend, causing the screen extending frame  70  to be reduced. 
         [0135]    The screen is, then, fixed to the reduced screen extending frame by means of adhesion, or the like. 
         [0136]    the state where fixation of the screen to the reduced screen extending frame is completed, the pressing force to the reduced screen extending frame exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0137]    As a result of releasing the pressing force to the reduced screen extending frame, the frame members that inwardly bend will all return to the shape of the state not being compressed, and as the open ends of the cut grooves  73   a,    73   b,    73   c,    73   d,    74   ab,    74   ba,    74   bc,    74   cb,    74   cd,    74   dc,    74   da,  and  74   ad  are widely open, the frame members  71   a,    71   b,    71   c,  and  71   d  extend to the outer side to extend the screen extending frame  70 , and therefore, a tensile force is exerted on the screen attached to the screen extending frame thus extended. 
         [0138]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
         [0139]    Insertion of a solid elastic element such as natural rubber or synthetic rubber or a non-solid spring such as a plate spring or a coil spring into the cut grooves  73   a,    73   b,    73   c,    73   d,    74   ab,    74   ba,    74   bc,    74   cb,    74   cd,    74   dc,    74   da,  and  74   ad  enables protection of the open ends and supplementation of elasticity. 
       EMBODIMENT 6 
       [0140]    The configuration of Embodiment 6 is shown in  FIG. 9 . Description of the function corresponding to that of  FIG. 3  or  FIG. 5  is omitted. In  FIG. 8 , (A) is an overall view of a screen extending frame  80 , (B) is an enlarged exploded view of a portion indicated by a dashed circle B in (A), and (C) is a cross-sectional view of a portion indicated by a dashed line C in (B). 
         [0141]    As shown in  FIG. 11(A)  of the overall view and  FIG. 11(B)  of the enlarged exploded view, the screen extending frame  80  is assembled with four frame members  81   a,    81   b,    81   c,  and  81   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0142]    On the four frame members  81   a,    81   b,    81   c,  and  81   d,  engagement grooves  82   a,    82   b,    82   c,  and  82   d  with which engagement elements formed in a screen extending jig are engaged each are formed. 
         [0143]    There are formed a narrow cut groove  83   a  in the outer side of the joint of the frame members  81   a  and  81   b  from the outer corner toward the inner corner; a narrow cut groove  83   b  in the outer side of the joint of the frame members  81   b  and  81   c  from the outer corner toward the inner corner; a narrow cut groove  83   c  in the outer side of the joint of the frame members  81   c  and  81   d  from the outer corner toward the inner corner; and a narrow cut groove  83   d  in the outer side of the joint of the frame members  81   d  and  81   a  from the outer corner toward the outer corner. 
         [0144]    All of the four frame members  81   a,    81   b,    81   c,  and  81   d  have the same cross-sectional shape, the engagement groove  82   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  81   a  as shown by the cross-section in  FIG. 11(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0145]    When the screen is attached to the screen extending frame  80 , the engagement elements of the extending jig are engaged with the engagement grooves  82   a,    82   b,    82   c,  and  82   d,  and then the extending jig is extended and reduced, the screen extending frame  80  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0146]    When the screen extending frame  80  configured by combining the four frame members  81   a,    81   b,    81   c,  and  81   d  is pressed in the inward direction using a tool such as the screen extending jig, a clamp, a vise, or the like, the open ends of the cut grooves  83   a,    83   b,    83   c,  and  83   d  are reduced, and accordingly, the frame members  81   a,    81   b,    81   c,  and  81   d  inwardly bend, causing the screen extending frame  80  to be reduced. 
         [0147]    The screen is, then, fixed to the reduced screen extending frame by means of adhesion, or the like. 
         [0148]    In the state where fixation of the screen to the reduced screen extending frame is completed, the pressing force to the reduced screen extending frame exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0149]    As a result of releasing the pressing force to the reduced screen extending frame, the frame members that inwardly bend will all return to the shape of the state of not being compressed, and as the open ends of the cut grooves  83   a,    83   b,    83   c,  and  83   d,  are widely open, the frame members  81   a,    81   b,    81   c,  and  81   d  extend to the outer side to extend the screen extending frame  80 , and therefore, a tensile force is exerted on the screen attached to the extended screen extending frame. 
         [0150]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
       EMBODIMENT 7 
       [0151]    Embodiment 7 that is obtained by modifying Embodiment 6 is shown in  FIG. 10 . Description of the function corresponding to that of  FIG. 3  or  FIG. 5  is omitted. In  FIG. 10 , (A) is an overall view of a screen extending frame  90 , (B) is an enlarged exploded view of a portion indicated by a dashed circle B in (A), and (C) is a cross-sectional view of a portion indicated by a dashed line C in (B). 
         [0152]    As shown in  FIG. 10(A)  of the overall view and  FIG. 10(B)  of the enlarged exploded view, the screen extending frame  90  is assembled with four frame members  91   a,    91   b,    91   c,  and  91   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0153]    On the four frame members  91   a,    91   b,    91   c,  and  91   d,  engagement grooves  92   a,    92   b,    92   c,  and  92   d  with which engagement elements formed in a screen extending jig are engaged each are formed. 
         [0154]    There are formed a narrow inclined cut groove  93   a  in the outer side of the joint of the frame members  91   a  and  91   b  from the outer corner toward the inner corner; a narrow inclined cut groove  93   b  in the outer side of the joint of the frame members  91   b  and  91   c  from the outer corner toward the inner corner; a narrow inclined cut groove  93   c  in the outer side of the joint of the frame members  91   c  and  91   d  from the outer corner toward the inner corner; and a narrow inclined cut groove  93   d  in the outer side of the joint of the frame members  91   d  and  91   a  from the outer corner to the inner corner. 
         [0155]    Furthermore, there are formed on the frame member  91   a  a narrow cut groove  94   ab  that is orthogonal to the outer side from the inner side at the joint with the frame member  91   b  and a narrow cut groove  94   ad  that is orthogonal to the outer side from the inner side at the joint thereof with the frame member  91   d;  on the frame member  91   b  a narrow cut groove  94   ba  that is orthogonal to the outer side from the inner side at the joint with the frame member  91   a  and a narrow cut groove  94   bc  that is orthogonal to the outer side from the inner side at the joint thereof with the frame member  91   c;  on the frame member  91   c  a narrow cut groove  94   cb  that is orthogonal to the outer side from the inner side at the joint with the frame member  91   b  and a narrow cut groove  94   cd  that is orthogonal to the outer side from the inner side at the joint thereof with the frame member  91   d;  and on the frame member  91   d  a narrow cut groove  94   dc  that is orthogonal to the outer side from the inner side at the joint with the frame member  91   c  and a narrow cut groove  94   da  that is orthogonal to the outer side from the inner side at the joint thereof with the frame member  91   a.    
         [0156]    All of the four frame members  91   a,    91   b,    91   c,  and  91   d  have the same cross-sectional shape, the engagement groove  92   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  91   a  as shown by the cross-section in  FIG. 12(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0157]    When the screen is attached to the screen extending frame  90 , the engagement elements of the extending jig are engaged with the engagement grooves  92   a,    92   b,    92   c,  and  92   d,  and the extending jig is extended and reduced, the screen extending frame  90  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0158]    When the screen extending frame  90  configured by combining the four frame members  91   a,    91   b,    91   c,  and  91   d  is pressed in the inward direction using a tool such as the screen extending jig, a clamp, a vise, or the like, the open ends of the cut grooves  93   a,    93   b,    93   c,  and  93   d  that are formed in the outer side are open wide, the open ends of the cut grooves  94   ab,    94   ba,    94   bc,    94   cb,    94   cd,    94   dc,    94   da,  and  94   ad  that are formed in the inner side are reduced, and accordingly, the frame members  91   a,    91   b,    91   c,  and  91   d  inwardly bend, causing the screen extending frame  10  to be reduced. 
         [0159]    The screen is, then, fixed to the reduced screen extending frame by means of adhesion, or the like. 
         [0160]    In the state where fixation of the screen to the reduced screen extending frame is completed, the pressing force to the reduced screen extending frame exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0161]    As a result of releasing the pressing force to the reduced screen extending frame, the frame members that inwardly bend will all return to the shape of the state of not being compressed, and as the open ends of the cut grooves  93   a,    93   b,    93   c,  and  93   d  are reduced and the open ends of the cut grooves  94   ab,    94   ba,    94   bc,    94   cb,    94   cd,    94   dc,    94   da,  and  94   ad  are widely open, the frame members  91   a,    91   b,    91   c,  and  91   d  extend to extend the screen extending frame  90 , and therefore, a tensile force is exerted on the screen attached to the extended screen extending frame. 
         [0162]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
         [0163]    Insertion of a solid elastic element such as natural rubber or synthetic rubber or a non-solid spring such as a plate spring or a coil spring into the cut grooves  93   a,    93   b,    93   c,    93   d,    94   ab,    94   ba,    94   bc,    94   cb,    94   cd,    94   dc,    94   da,  and  94   ad  enables protection of the open ends and supplementation of elasticity. 
       EMBODIMENT 8 
       [0164]    Embodiment 8 that is another example obtained by modifying Embodiment 6 is shown in  FIG. 11 . 
         [0165]    Description of the function corresponding to that of  FIG. 3  or  FIG. 5  is omitted. In  FIG. 11 , (A) is an overall view of a screen extending frame  100 , (B) is an enlarged exploded view of a portion indicated by a dashed circle B in (A), and (C) is a cross-sectional view of a portion indicated by a dashed line C in (B). 
         [0166]    As shown in  FIG. 11(A)  of the overall view and  FIG. 11(B)  of the enlarged exploded view, the screen extending frame  100  is assembled with four frame members  101   a,    101   b,    101   c,  and  101   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0167]    On the four frame members  101   a,    101   b,    101   c,  and  101   d,  engagement grooves  102   a,    102   b,    102   c,  and  102   d  with which engagement elements formed in a screen extending jig are engaged each are formed. 
         [0168]    There are formed a narrow inclined cut groove  103   a  in the outer side of the joint of the frame members  101   a  and  101   b  from the outer corner to the inner corner; a narrow inclined cut groove  103   b  in the outer side of the joint of the frame members  101   b  and  101   c  from the outer corner to the inner corner; a narrow inclined cut groove  103   c  in the outer side of the joint of the frame members  101   c  and  101   d  from the outer corner to the inner corner; and a narrow inclined cut groove  103   d  in the outer side of the joint of the frame members  101   d  and  101   a  from the outer corner to the inner corner. 
         [0169]    Furthermore, there are formed on the frame member  101   a  a cut groove  104   ab  that is orthogonal to the inner side from the outer side at the joint with the frame member  101   b  and a cut groove  104   ad  that is orthogonal to the inner side from the outer side at the joint thereof with the frame member  101   d;  on the frame member  101   b  a cut groove  104   ba  that is orthogonal to the inner side from the outer side at the joint with the frame member  101   a  and a cut groove  104   bc  that is orthogonal to the inner side from the outer side at the joint thereof with the frame member  101   c;  on the frame member  101   c  a cut groove  104   cb  that is orthogonal to the inner side from the outer side at the joint with the frame member  101   b  and a cut groove  104   cd  that is orthogonal to the inner side from the outer side at the joint thereof with the frame member  101   d;  and on the frame member  101   d  a cut groove  104   dc  that is orthogonal to the inner side from the outer side at the joint with the frame member  101   c  and a cut groove  104   da  that is orthogonal to the inner side from the outer side at the joint thereof with the frame member  101   a.    
         [0170]    All of the four frame members  101   a,    101   b,    101   c,  and  101   d  have the same cross-sectional shape, the engagement groove  102   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  101   a  as shown by the cross-section in  FIG. 13(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0171]    When the screen is attached to the screen extending frame  100 , the engagement elements of the extending jig are engaged with the engagement grooves  102   a,    102   b,    102   c,  and  102   d,  and the extending jig is extended and reduced, the screen extending frame  100  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0172]    When the screen extending frame  100  configured by combining the four frame members  101   a,    101   b,    101   c,  and  101   d  is pressed in the inward direction using a tool such as the screen extending jig, a clamp, a vise, or the like, the open ends of the cut grooves  103   a,    103   b,    103   c,  and  103   d  are widely open, and open ends of the cut grooves  104   ab,    104   ba,    104   bc,    104   cb,    104   cd,    104   dc,    104   da,  and  104   ad  are reduced, and accordingly, the frame members  101   a,    101   b,    101   c,  and  101   d  inwardly bend, causing the screen extending frame  100  to be reduced. 
         [0173]    The screen is, then, fixed to the reduced screen extending frame by means of adhesion, or the like. 
         [0174]    In the state where fixation of the screen to the reduced screen extending frame is completed, the pressing force to the reduced screen extending frame exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0175]    As a result of releasing the pressing force to the reduced screen extending frame, the frame members that inwardly bend will all return to the shape of the state of not being compressed, and as the open ends of the cut grooves  103   a,    103   b,    103   c,  and  103   d  are reduced and the open ends of the cut grooves  104   ab,    104   ba,    104   bc,    104   cb,    104   cd,    104   dc,    104   da,  and  104   ad  are reduced, the frame members  101   a,    101   b,    101   c,  and  101   d  outwardly extend to extend the screen extending frame  100 , and therefore, a tensile force is exerted on the screen attached to the screen extending frame thus extended. 
         [0176]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
         [0177]    Insertion of a solid elastic element such as natural rubber or synthetic rubber or a non-solid spring such as a plate spring or a coil spring into the cut grooves  103   a,    103   b,    103   c,    103   d,    104   ab,    104   ba,    104   bc,    104   cb,    104   cd,    104   dc,    104   da,  and  104   ad  enables protection of the open ends and supplementation of elasticity. 
       EMBODIMENT 9 
       [0178]    Embodiment 9 that is another example obtained by modifying Embodiment 6 is shown in  FIG. 12   
         [0179]    Description of the function corresponding to that of  FIG. 3  or  FIG. 5  is omitted. In  FIG. 12 , (A) is an overall view of a screen extending frame  110 , (B) is an enlarged exploded view of a portion indicated by a dashed circle B in (A), and (C) is a cross-sectional view of a portion indicated by a dashed line C in (B). 
         [0180]    As shown in  FIG. 12(A)  of the overall view and  FIG. 12(B)  of the enlarged exploded view, the screen extending frame  110  is assembled with four frame members  111   a,    111   b,    111   c,  and  111   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0181]    On the four frame members  111   a,    111   b,    111   c,  and  111   d,  engagement grooves  112   a,    112   b,    112   c,  and  112   d  with which engagement elements formed in a screen extending jig are engaged each are formed. 
         [0182]    There are formed a narrow inclined cut groove  113   a  in the outer side of the joint of the frame members  111   a  and  111   b  from the outer corner to the inner corner; a narrow inclined cut groove  113   b  in the outer side of the joint of the frame members  111   b  and  111   c  from the outer corner to the inner corner; a narrow inclined cut groove  113   c  in the outer side of the joint of the frame members  111   c  and  111   d  from the outer corner to the inner corner; and a narrow inclined cut groove  113   d  in the outer side of the joint of the frame members  111   d  and  111   a  from the outer corner to the inner corner. 
         [0183]    Furthermore, there are formed on the frame member  111   a  a narrow inclined cut groove  114   ab  that leads to the outer side from the inner side of the joint with the frame member  111   b  and a narrow inclined cut groove  114   ad  that leads to the outer side from the inner side of the joint thereof with the frame member  111   d;  on the frame member  111   b  a narrow inclined cut groove  114   ba  that leads to the outer side from the inner side of the joint with the frame member  111   a  and a narrow inclined cut groove  114   bc  that leads to the outer side from the inner side of the joint thereof with the frame member  111   c;  on the frame member  111   c  a narrow inclined cut groove  114   cb  that leads to the outer side from the inner side of the joint with the frame member  111   b  and a narrow inclined cut groove  114   cd  that leads to the outer side from the inner side of the joint thereof with the frame member  111   d;  and on the frame member  111   d  a narrow inclined cut groove  114   dc  that leads to the outer side from the inner side of the joint with the frame member  111   c  and a narrow inclined cut groove  114   da  that leads to the outer side from the inner side of the joint thereof with the frame member  111   a.    
         [0184]    All of the four frame members  111   a,    111   b,    111   c,  and  111   d  have the same cross-sectional shape, the engagement groove  112   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  111   a  as shown by the cross-section in  FIG. 14(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0185]    When the screen is attached to the screen extending frame  110 , the engagement elements of the extending jig are engaged with the engagement grooves  112   a,    112   b,    112   c,  and  112   d,  and the extending jig is extended and reduced, the screen extending frame  110  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0186]    When the screen extending frame  110  configured by combining the four frame members  111   a,    111   b,    111   c,  and  111   d  is pressed in the inward direction using a tool such as the screen extending jig, a clamp, a vise, or the like, the open ends of the cut grooves  113   a,    113   b,    113   c,  and  113   d  that are formed in the outer side are widely open, and open ends of the cut grooves  114   ab,    114   ba,    114   bc,    114   cb,    114   cd,    114   dc,    114   da,  and  114   ad  that are formed in the inner side are reduced, and accordingly, the frame members  111   a,    111   b,    111   c,  and  111   d  inwardly bend, causing the screen extending frame  110  to be reduced. 
         [0187]    The screen is, then, fixed to the reduced screen extending frame by means of adhesion, or the like. 
         [0188]    In the state where fixation of the screen to the reduced screen extending frame is completed, the pressing force to the reduced screen extending frame exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0189]    As a result of releasing the pressing force to the reduced screen extending frame, the frame members that inwardly bend will all return to the shape of the state not being compressed, and as the open ends of the cut grooves  113   a,    113   b,    113   c,  and  113   d  that are formed in the outer side are reduced and the open ends of the cut grooves  114   ab,    114   ba,    114   bc,    114   cb,    114   cd,    114   dc,    114   da,  and  114   ad  that are formed in the inner side are widely open, the frame members  111   a,    111   b,    111   c,  and  111   d  extend outwardly to extend the screen extending frame  110 , and therefore, a tensile force is exerted on the screen attached to the screen extending frame thus extended. 
         [0190]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
         [0191]    Insertion of a solid elastic element such as natural rubber or synthetic rubber or a non-solid spring such as a plate spring or a coil spring into the cut grooves  113   a,    113   b,    113   c,    113   d,    114   ab,    114   ba,    114   bc,    114   cb,    114   cd,    114   dc,    114   da,  and  114   ad  enables protection of the open ends and supplementation of elasticity. 
       EMBODIMENT 10 
       [0192]    Embodiment 10 that is another example obtained by modifying Embodiment 6 is shown in  FIG. 13 . 
         [0193]    Description of the function corresponding to that of  FIG. 5  or  FIG. 7  is omitted. In  FIG. 13 , (A) is an overall view of a screen extending frame  120 , (B) is an enlarged exploded view of a portion indicated by a dashed circle B in (A), and (C) is a cross-sectional view of a portion indicated by a dashed line C in (B). 
         [0194]    As shown in  FIG. 13(A)  of the overall view and  FIG. 13(B)  of the enlarged exploded view, the screen extending frame  120  is assembled with four frame members  121   a,    121   b,    121   c,  and  121   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0195]    On the four frame members  121   a,    121   b,    121   c,  and  121   d,  engagement grooves  122   a,    122   b,    122   c,  and  122   d  with which engagement elements formed in a screen extending jig are engaged each are formed. 
         [0196]    There are formed a narrow inclined cut groove  123   a  in the outer side of the joint of the frame members  121   a  and  121   b  from the outer corner to the inner corner; a narrow inclined cut groove  123   b  in the outer side of the joint of the frame members  121   b  and  121   c  from the outer corner to the inner corner; a narrow inclined cut groove  123   c  in the outer side of the joint of the frame members  121   c  and  121   d  from the outer corner to the inner corner; and a narrow inclined cut groove  123   d  in the outer side of the joint of the frame members  121   d  and  121   a  from the outer corner to the inner corner. 
         [0197]    Furthermore, there are formed on the frame member  121   a  a narrow inclined cut groove  124   ab  that leads to the inner side from the outer side at the joint with the frame member  121   b  and a narrow inclined cut groove  124   ad  that leads to the inner side from the outer side at the joint thereof with the frame member  121   d;  on the frame member  121   b  a narrow inclined cut groove  124   ba  that leads to the inner side from the outer side at the joint with the frame member  121   a  and a narrow inclined cut groove  124   bc  that leads to the inner side from the outer side at the joint thereof with the frame member  121   c;  on the frame member  121   c  a narrow inclined cut groove  124   cb  that leads to the inner side from the outer side at the joint with the frame member  121   b  and a narrow inclined cut groove  124   cd  that leads to the inner side from the outer side at the joint thereof with the frame member  121   d;  and on the frame member  121   d  a narrow inclined cut groove  124   dc  that leads to the inner side from the outer side at the joint with the frame member  121   c  and a narrow inclined cut groove  124   da  that leads to the inner side from the outer side at the joint thereof with the frame member  121   a.    
         [0198]    All of the four frame members  121   a,    121   b,    121   c,  and  121   d  have the same cross-sectional shape, the engagement groove  122   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  121   a  as shown by the cross-section in  FIG. 15(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0199]    When the screen is attached to the screen extending frame  120 , the engagement elements of the extending jig are engaged with the engagement grooves  122   a,    122   b,    122   c,  and  122   d,  and the extending jig is extended and reduced, the screen extending frame  120  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0200]    When the screen extending frame  120  configured by combining the four frame members  121   a,    121   b,    121   c,  and  121   d  is pressed in the inward direction using a tool such as the screen extending jig, a clamp, a vise, or the like, the open ends of the cut grooves  123   a,    123   b,    123   c,    123   d,    124   ab,    124   ba,    124   bc,    124   cb,    124   cd,    124   dc,    124   da,  and  124   ad  are widely open, and accordingly, the frame members  121   a,    121   b,    121   c,  and  121   d  inwardly bend, causing the screen extending frame  120  to be reduced. 
         [0201]    The screen is, then, fixed to the reduced screen extending frame by means of adhesion, or the like. 
         [0202]    In the state where fixation of the screen to the reduced screen extending frame is completed, the pressing force to the reduced screen extending frame exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0203]    As a result of releasing the pressing force to the reduced screen extending frame, the frame members that inwardly bend will all return to the shape of the state not being compressed, and as the open ends of the cut grooves  123   a,    123   b,    123   c,    123   d,    124   ab,    124   ba,    124   bc,    124   cb,    124   cd,    124   dc,    124   da,  and  124   ad  are reduced, the frame members  121   a,    121   b,    121   c,  and  121   d  extend outwardly to extend the screen extending frame  120 , and therefore, a tensile force is exerted on the screen fixed to the extended screen extending frame. 
         [0204]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
         [0205]    Insertion of a solid elastic element such as natural rubber or synthetic rubber or a non-solid spring such as a plate spring or a coil spring into the cut grooves  123   a,    123   b,    123   c,    123   d,    124   ab,    124   ba,    124   bc,    124   cb,    124   cd,    124   dc,    124   da,  and  124   ad  enables protection of the open ends and supplementation of elasticity. 
       EMBODIMENT 11 
       [0206]    Embodiment 11 is shown in  FIG. 14   
         [0207]    Description of the function corresponding to that of  FIG. 3  or  FIG. 5  is omitted. 
         [0208]    In  FIG. 14 , (A) is an overall view of a screen extending frame  130 , (B) is an enlarged exploded view of a portion indicated by a dashed circle B in (A), and (C) is a cross-sectional view of a portion indicated by a dashed line C in (B). 
         [0209]    As shown in  FIG. 14(A)  of the overall view and  FIG. 14(B)  of the enlarged exploded view, the screen extending frame  130  is assembled with four frame members  131   a,    131   b,    131   c,  and  131   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0210]    On the four frame members  131   a,    131   b,    131   c,  and  131   d,  engagement grooves  132   a,    132   b,    132   c,  and  132   d  with which engagement elements formed in a screen extending jig are engaged each are formed. 
         [0211]    There are formed on the frame member  131   a  a narrow cut groove  134   ab  that leads to the inner side orthogonally from the outer side at the joint with the frame member  131   b  and a narrow cut groove  134   ad  that leads to the inner side orthogonally from the outer side at the joint thereof with the frame member  131   d;  on the frame member  131   b  a narrow cut groove  134   ba  that leads to the inner side orthogonally from the outer side at the joint with the frame member  131   a  and a narrow cut groove  134   bc  that leads to the inner side orthogonally from the outer side at the joint thereof with the frame member  131   c;  on the frame member  131   c  a narrow cut groove  134   cb  that leads to the inner side orthogonally from the outer side at the joint with the frame member  131   b  and a narrow cut groove  134   cd  that leads to the inner side orthogonally from the outer side at the joint thereof with the frame member  131   d;  and on the frame member  131   d  a narrow cut groove  134   dc  that leads to the inner side orthogonally from the outer side at the joint with the frame member  131   c  and a narrow cut groove  134   da  that leads to the inner side orthogonally from the outer side at the joint thereof with the frame member  131   a.    
         [0212]    All of the four frame members  131   a,    131   b,    131   c,  and  131   d  have the same cross-sectional shape, the engagement groove  132   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  131   a  as shown by the cross-section in  FIG. 16(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0213]    When the screen is attached to the screen extending frame  130 , the engagement elements of the extending jig are engaged with the engagement grooves  132   a,    132   b,    132   c,  and  132   d,  and the extending jig is extended and reduced, the screen extending frame  130  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0214]    When the screen extending frame  130  configured by combining the four frame members  131   a,    131   b,    131   c,  and  131   d  is pressed in the inward direction using a tool such as the screen extending jig, a clamp, a vise, or the like, the open ends of the cut grooves  134   ab,    134   ba,    134   bc,    134   cb,    134   cd,    134   dc,    134   da,  and  134   ad  that are formed in the outer side are reduced, and accordingly, the frame members  131   a,    131   b,    131   c,  and  131   d  inwardly bend, causing the screen extending frame  130  to be reduced. 
         [0215]    The screen is, then, fixed to the reduced screen extending frame by means of adhesion, or the like. 
         [0216]    In the state where fixation of the screen to the reduced screen extending frame is completed, the pressing force to the reduced screen extending frame exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0217]    As a result of releasing the pressing force to the reduced screen extending frame, the frame members that inwardly bend will all return to the shape of the state not being compressed, and as the open ends of the cut grooves  134   ab,    134   ba,    134   bc,    134   cb,    134   cd,    134   dc,    134   da,  and  134   ad  that are formed in the outer side are widely open, the frame members  131   a,    131   b,    131   c,  and  131   d  extend outwardly to extend the screen extending frame  110 , and therefore, a tensile force is exerted on the screen attached to the extended screen extending frame. 
         [0218]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
         [0219]    Insertion of a solid elastic element such as natural rubber or synthetic rubber or a non-solid spring such as a plate spring or a coil spring into the cut grooves  134   ab,    134   ba,    134   bc,    134   cb,    134   cd,    134   dc,    134   da,  and  134   ad  enables protection of the open ends and supplementation of elasticity. 
       EMBODIMENT 12 
       [0220]    Embodiment  12  is shown in  FIG. 15 . 
         [0221]    Description of the function corresponding to that of  FIG. 3  or  FIG. 5  is omitted. 
         [0222]    In the drawing, (A) is an overall view of a screen extending frame  140 , (B) is an enlarged exploded view of a portion indicated by a dashed circle B in (A), and (C) is a cross-sectional view of a portion indicated by a dashed line C in (B). 
         [0223]    As shown in  FIG. 15  (A) of the overall view and  FIG. 15  (B) of the enlarged exploded view, the screen extending frame  140  is assembled with four frame members  141   a,    141   b,    141   c,  and  141   d  to be formed in a rectangular shape, and structured by fixedly joined by means of welding, or the like. 
         [0224]    On the four frame members  141   a,    141   b,    141   c,  and  141   d,  engagement grooves  142   a,    142   b,    142   c,  and  142   d  with which engagement elements formed in a screen extending jig are engaged each are formed. 
         [0225]    There are formed on the frame member  141   a  a narrow cut groove  144   ab  that leads to the outer side orthogonally from the inner side at the joint with the frame member  141   b  and a narrow cut groove  144   ad  that leads to the outer side orthogonally from the inner side at the joint thereof with the frame member  141   d;  on the frame member  141   b  a narrow cut groove  144   ba  that leads to the outer side orthogonally from the inner side at the joint with the frame member  141   a  and a narrow cut groove  144   bc  that leads to the outer side orthogonally from the inner side at the joint thereof with the frame member  141   c;  on the frame member  141   c  a narrow cut groove  144   cb  that leads to the outer side orthogonally from the inner side at the joint with the frame member  141   b  and a narrow cut groove  144   cd  that leads to the outer side orthogonally from the inner side at the joint thereof with the frame member  141   d;  and on the frame member  141   d  a narrow cut groove  144   dc  that leads to the outer side orthogonally from the inner side at the joint with the frame member  141   c  and a narrow cut groove  144   da  that leads to the outer side orthogonally from the inner side at the joint thereof with the frame member  141   a.    
         [0226]    All of the four frame members  141   a,    141   b,    141   c,  and  141   d  have the same cross-sectional shape, the engagement groove  142   a  with which an engagement element of the screen extending jig is engaged is formed on one face of the frame member  141   a  as shown by the cross-section in  FIG. 17(C) , and the opposite face is set to be a plane in order to attach the screen thereto. 
         [0227]    When the screen is attached to the screen extending frame  140 , the engagement elements of the extending jig are engaged with the engagement grooves  142   a,    142   b,    142   c,  and  142   d,  and the extending jig is extended and reduced, the screen extending frame  140  extends and reduces, and accordingly, the tensile force to the screen is adjusted. 
         [0228]    When the screen extending frame  140  configured by combining the four frame members  141   a,    141   b,    141   c,  and  141   d  is pressed in the inward direction using a tool such as the screen extending jig, a clamp, a vise, or the like, the open ends of the cut grooves  143   ab,    143   ba,    143   bc,    143   cb,    143   cd,    143   dc,    143   da,  and  143   ad  that are formed in the inner side are reduced, and accordingly, the frame members  141   a,    141   b,    141   c,  and  141   d  inwardly bend, causing the screen extending frame  140  to be reduced. 
         [0229]    The screen is, then, fixed to the reduced screen extending frame by means of adhesion, or the like. 
         [0230]    In the state where fixation of the screen to the reduced screen extending frame is completed, the pressing force to the reduced screen extending frame exerted by the screen extending jig, the clamp, the vice, or the like is released. 
         [0231]    As a result of releasing the pressing force to the reduced screen extending frame, the frame members that inwardly bend will all return to the shape of the state not being compressed, and as the open ends of the cut grooves  144   ab,    144   ba,    144   bc,    144   cb,    144   cd,    144   dc,    144   da,  and  144   ad  that are formed in the inner side are widely open, the frame members  141   a,    141   b,    141   c,  and  141   d  extend outwardly to extend the screen extending frame  140 , and therefore, a tensile force is exerted on the screen attached to the extended screen extending frame. 
         [0232]    Since the tensile force is exerted even in the state of not using the extending jig, it is possible to keep the screen to be in tension even in the state where the screen is simply fixed to the screen extending frame, and there occurs no sagging in the screen. 
         [0233]    Insertion of a solid elastic element such as natural rubber or synthetic rubber or a non-solid spring such as a plate spring or a coil spring into the cut grooves  144   ab,    144   ba,    144   bc,    144   cb,    144   cd,    144   dc,    144   da,  and  144   ad  enables protection of the open ends and supplementation of elasticity. INDUSTRIAL APPLICABILITY 
         [0234]    As understood from the above description, according to the screen extending frame of the present invention, since a tensile force is exerted on the screen thus attached thereto, even in the state of not using an extending jig, it is possible to keep the screen to be in tension even when the screen is simply fixed in the screen extending frame, and printing is possible without using the screen extending jig with no sagging in the screen. 
         [0235]    Therefore, it is possible to safely store and transport the screen even after being taken out from a screen extending jig that is heavy, bulky, and expensive, with regard to storage and transportation. That is useful for managing the screen to be used in screen printing. 
         [0236]    In addition, installation of a mechanism for mounting a screen extending frame on a screen printing machine and a mechanism for expanding and reducing the mounted screen extending frame makes an overall configuration of the printing machine simple. 
         [0237]    REFERENCE NUMERALS 
         [0238]      1  screen extending jig 
         [0239]      2  screen extending frame 
         [0240]      3  screen 
         [0241]      4 ,  32   a ˜ 32   d,    42   a ˜ 42   d,    52   a ˜ 52   d,    62   a ˜ 62   d,    72   a ˜ 72   d,    82   a ˜ 82   d,    92   a ˜ 92   d,    102   a ˜ 102   d,    112   a ˜ 112   d,    122   a ˜ 122   d,    132   a ˜ 132   d  engaging grooves 
         [0242]      5  engaging element 
         [0243]      10 ,  20 ,  30 ,  40 ,  50 ,  60 ,  70 ,  80 ,  90 ,  100 ,  11 - 0 ,  120 ,  130 ,  1401  screen extending frame 
         [0244]      11   a ˜ 11   d,    21   a ˜ 21   d,    31   a ˜ 31   d,    41   a ˜ 41   d,    51   a ˜ 51   d,    61   a ˜ 61   d,    71   a ˜ 71   d,    81   a ˜ 81   d,    91   a ˜ 91   d,    101   a ˜ 101   d,    111   a ˜ 111   d,    121   a ˜ 121   d,    131   a ˜ 131   d,    141   a ˜ 141   d  frame members 
         [0245]      13   a,    23   a ˜ 23   d,    163   a,    173   a ˜ 173   d,    43   a  corner member 
         [0246]      33   a ˜ 33   d,    43   a ˜ 43   d,    53   a ˜ 53   d,    63   a ˜ 63   d,    73   a ˜ 73   d,    83   a ˜ 83   d,    93   a ˜ 93   d,    103   a ˜ 103   d,    123   a ˜ 123   d  cutting groove