Patent Publication Number: US-2016230452-A1

Title: Opening/closing apparatus for opening portion

Description:
TECHNICAL FIELD 
     The present invention relates to an opening/closing apparatus for an opening portion, such as a window blind apparatus or a shutter apparatus which is disposed in an opening portion such as a window or an entrance of a building and is used to open and close the opening portion. 
     BACKGROUND ART 
     As described in Patent Document 1, for example, a window blind apparatus comprises: a frame body which is disposed in an opening portion, such as a window, of a building; a plurality of slats juxtaposed to each other in an opening portion surrounded by the frame body; a suspending mechanism for suspending an uppermost slat among the plurality of slats; a link mechanism which links the plurality of slats to each other and is foldable; and a raising and lowering mechanism for raising and lowering the plurality of slats by raising them, starting with a lowermost slat among the plurality of slats, and by lowering them, starting with the lowermost slat. 
     PRIOR ART DOCUMENTS 
     Patent Documents 
     Patent Document 1: Republication of WO2011/09907 
     Patent Document 2: JP-A-2011432806 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     Incidentally, in such a window blind apparatus, the raising and lowering of the plurality of slats in the opening and closing of the opening portion is automatically effected by an electric motor. However, in both cases where, in substitution for the electric motor, a pulley is secured to a rotating shaft, a cord or a ball chain is wound around the pulley, and through the manual traveling of the cord or the ball chain for raising and lowering the slats, the opening portion closed by the plurality of slats is arranged to be opened by raising the slats, starting with a lowermost slat and where the opened opening portion is arranged to be closed by raising the slats, starting with an uppermost slat, the load of the slats increases in correspondence with the number of the slats being raised, so that it is necessary to apply a gradually larger raising force to the lowermost or uppermost slat as the opening degree or the closing degree increases. As a result, the operator who performs the manual traveling of the cord or the ball chain needs to apply a manual traveling force corresponding thereto to the cord or the ball chain and is made to feel such as a difficulty in performing the operation. In addition, it is difficult to perform a specific opening and closing operation of the opening portion by the plurality of slats through a specific manual operation of the cord or the ball chain by the operator, e.g., automatic opening and closing operation of the opening portion by the plurality of slats through an instantaneous manual operation of the cord or the ball chain by the operator. 
     Such a problem is not limited to the window blind apparatus and can also occur in a case where the cord or the ball chain is not used in a shutter apparatus which is provided with the cord or the ball chain or in a case where the lowermost slat is manually raised and lowered to open and close the opening portion in a shutter apparatus which is not provided with the cord or the ball chain. 
     The present invention has been devised in view of the above-described aspects, and its object is to provide an opening/closing apparatus for an opening portion which can be configured to be capable of overcoming the difficulty in manual operation by the operator, and which can also be configured to make it possible to perform a specific opening and closing operation with respect to the opening portion by the plurality of slats through a specific manual operation by the operator. 
     Means for Solving the Problems 
     An opening/closing apparatus for an opening portion in accordance with the present invention comprises: a frame body which is disposed in an opening portion of a building; a plurality of slats which are juxtaposed to each other in a vertical direction in the opening portion surrounded by the frame body and which open and close the opening portion; a connecting mechanism for mutually connecting vertically adjacent ones of the plurality of slats; and a reaction force generating mechanism for generating a reaction force which increases in correspondence with a change in the number of the slats being raised in the opening portion and is oriented in an opposite direction to a direction of a load of the slats in the opening portion, wherein the raising of the slats in the opening portion is effected by at least the increasing reaction force generated by the reaction force generating mechanism. 
     According to the opening/closing apparatus for an opening portion in accordance with the present invention, since a reaction force generating mechanism is provided, and the raising of the slats in the opening portion is effected by at least the increasing reaction force generated by the reaction force generating mechanism, it is possible to assist the manual operating force of the operator by that reaction force. In consequence, it is possible to overcome the difficulty in manual operation by the operator; furthermore, by setting a rate of increase of the reaction force, as desired, it becomes possible to perform a specific opening and closing operation with respect to the opening portion by the plurality of slats through a specific manual operation by the operator. 
     For example, in both cases where the arrangement provided is such that the plurality of slats in the opening portion closed by the plurality of slats are raised, starting with a lowermost slat, and upper slats are consecutively overlapped on the lowermost slat to thereby open the opening portion, and where the arrangement provided is such that the plurality of slats in the opened opening portion are raised, starting with an uppermost slat, and lower slats are consecutively lifted by the uppermost slat to thereby close the opening portion, by providing an arrangement in which a rate of increase of a reaction force generated by such a reaction force generating mechanism is made equal to a rate of increase of the load of the slats being raised and members which are raised in association with the slats being raised, even if the number of the slats being raised in the opening and closing of the opening portion increases, it is possible to perform the opening and closing of the opening portion with a substantially constant manual operating force without enlarging a manual operating force of an operator, thereby making it possible to overcome the difficulty in manual operation by the operator. In addition, by providing an arrangement in which the rate of increase of the reaction force generated by the reaction force generating mechanism is made greater than the rate of increase of the load of the slats being raised and the members which are raised in association with the slats being raised, in the case where the arrangement provided is such that the plurality of slats in the opening portion closed by the plurality of slats are raised, starting with the lowermost slat, and upper slats are consecutively overlapped on the lowermost slat to thereby open the opening portion, when an instantaneous operating force is imparted to the lowermost slat from outside to open the opening portion in the closed state of the opening portion, the slats can be consecutively raised automatically, starting with the lowermost slat. Meanwhile, in the case where the arrangement provided is such that the plurality of slats in the opened opening portion are raised, starting with the uppermost slat, and lower slats are consecutively lifted by the uppermost slat to thereby close the opening portion, when an instantaneous operating force is imparted to the uppermost slat from outside to close the opening portion in the open state of the opening portion, the slats can be consecutively raised automatically, starting with the uppermost slat. In either case, it becomes possible to effect the opening and closing of the opening portion automatically despite the manual operation. Furthermore, in a case where the arrangement provided is such that the plurality of slats in the opening portion closed by the plurality of slats are simultaneously raised and the uppermost slat and the following lower slats are consecutively wound up owing to this raising to thereby open the opening portion, when an instantaneous operating force is imparted from outside to the plurality of slats closing the opening portion to open the opening portion in the closed state of the opening portion, the winding of the slats can be effected automatically. Thus, it becomes possible to perform a specific opening and closing operation with respect to the opening portion by the plurality of slats through a specific manual operation by the operator. It should be noted that, in the present invention, the reaction force of the reaction force generating mechanism may be generated from halfway in the raising of the slats. 
     In one example of the opening/closing apparatus for an opening portion in accordance with the present invention, the opening/closing apparatus for an opening portion further comprises a raising and lowering mechanism for raising and lowering the plurality of slats in the opening and closing of the opening portion, the reaction force generating mechanism is adapted to impart to the raising and lowering mechanism the reaction force which increases in correspondence with an increase of the load in the opening portion corresponding to an increase in the number of the slats being raised by the raising and lowering mechanism in the opening portion, and the raising and lowering mechanism is adapted to effect the raising of the slats in the opening portion by the reaction force imparted by at least the reaction force generating mechanism. In such a case, the raising and lowering mechanism may be adapted to effect the raising of the slats in the opening portion also by a raising force imparted from an outside in addition to the reaction force. 
     In a preferred example, the reaction force generating mechanism is adapted to impart to the raising and lowering mechanism the reaction force which decreases in correspondence with a decrease of the load of the slats in the opening portion corresponding to an decrease in the number of the slats being lowered by the raising and lowering mechanism in the opening portion. In such an example as well, by providing an arrangement similar to the one described above, the configuration makes it possible to overcome the difficulty in manual operation by the operator in the lowering of the slats, and makes it possible to perform a specific opening and closing operation with respect to the opening portion by the plurality of slats through a specific manual operation by the operator. 
     In the opening/closing apparatus for an opening portion in accordance with the present invention, the raising and lowering mechanism may include a flexible elongated member, a traveling mechanism for causing the elongated member to travel, and a transmitting mechanism for transmitting the traveling of the elongated member to the slats, in which case the traveling mechanism includes a rotating body around which the elongated member is wound and which causes the elongated member to travel as the rotating body rotates and a rotational force imparting mechanism for imparting a rotational force to the rotating body to rotate the rotating body, and the transmitting mechanism connects to a slat one end of one suspended portion of the elongated member suspended from the rotating body, so as to transmit the traveling of the elongated member to the slats, wherein the reaction force generating mechanism includes a flexible elongated weight connected at one end thereof to another suspended portion, suspended from the rotating body, of the elongated member wound around the rotating body, and a supporting member for accommodating a moving portion of the weight which moved as the other suspended portion of the elongated member suspended from the rotating body travels in an upward direction, so as to support that moving portion. Further, the moving portion of the weight supported on the supporting member may be adapted to be drawn out from the supporting member as the other suspended portion of the elongated member suspended from the rotating body travels in a downward direction, so as to allow the support thereof on the supporting member to be gradually released, and the reaction force generating mechanism may be adapted to allow a load of a drawn-out portion of the weight being drawn out from the supporting member to be imparted to the raising and lowering mechanism as the reaction force. 
     In addition, in the opening/closing apparatus for an opening portion in accordance with the present invention, the raising and lowering mechanism may include a flexible elongated member, a traveling mechanism for causing the elongated member to travel, and a transmitting mechanism for transmitting the traveling of the elongated member to the lowermost slat, in which case the traveling mechanism includes a first rotating body around which the elongated member is wound, a rotating mechanism for rotating the first rotating body, and a rotational force imparting mechanism for imparting a rotational force to the rotation mechanism, and the transmitting mechanism connecting to a slat one end of one suspended portion of the elongated member suspended from the first rotating body, so as to transmit the traveling of the elongated member to the slats. Further, the reaction force generating mechanism includes a second rotating body and a flexible elongated weight wound around the second rotating body, one end of one suspended portion, suspended from the second rotating body, of the weight wound around the second rotating body being connected to one end of another suspended portion, suspended from the first rotating body, of the elongated member wound around the first rotating body, one end of another suspended portion, suspended from the second rotating body, of the weight wound around the second rotating body being formed as a free end. Furthermore, the reaction force generating mechanism may be adapted to allow a difference between a load of the one suspended portion, suspended from the second rotating body, of the weight wound around the second rotating body and a load of the other suspended portion, suspended from the second rotating body, of the weight wound around the second rotating body to be imparted to the raising and lowering mechanism as the reaction force. 
     In the present invention, the flexible elongated weight may be constituted by, for example, a plurality of weight elements which are connected to each other and are capable of generating a reaction force which increases or decreases in correspondence with an increase or decrease of the load of the slats corresponding to the number of the slats being raised or lowered. Preferably, the weight is constituted by a no-back chain having chain elements as the weight elements. Such weight elements may have a mutually identical mass, but may have mutually different masses, and in a case where a plurality of weight elements having such mutually different masses are used, weight elements whose masses consecutively increase from one end to the other end may be arrayed in a row of weight elements constituted by a plurality of mutually connected weight elements. 
     In the present invention, a vertically lowermost slat among the plurality of slats in the opening portion may be adapted to be precedingly raised to open the opening portion, and the lowermost slat is adapted to be precedingly lowered to close the opening portion. Alternatively, a vertically uppermost slat among the plurality of slats in the opening portion may be adapted to be precedingly raised to close the opening, and the uppermost slat may be adapted to be precedingly lowered to open the opening portion. 
     In another example of the present invention, the plurality of slats in the opening portion are adapted to be simultaneously raised or lowered to open or close the opening portion. In such an example, the opening/closing apparatus for an opening portion may further comprise a rotatable winding member. In the example in which the winding member is provided, when the opening portion is closed, the plurality of slats in the opening portion may be adapted to be consecutively wound up around the winding member, starting with an uppermost slat, whereas when the opening portion is opened, the slats wound up around the winding member may be adapted to be paid out, and the reaction force generating mechanism may be adapted to generate a reaction force which increases in correspondence with the number of the slats which are wound up around the winding member. 
     In the example of the opening/closing apparatus for an opening portion in accordance with the present invention in which the plurality of slats in the opening portion are adapted to be simultaneously raised or lowered to open or close the opening portion, the reaction force generating mechanism may include a flexible elongated weight capable of traveling; a rotatable rotating body around which the weight is wound, so as to allow the rotating body to be rotated as the weight travels; and a connecting mechanism which connects a slat in the opening portion to one suspended portion of the weight suspended from the rotating body, so as to transmit the raising of the slats in the opening portion to the one suspended portion. In this case, the connecting mechanism may be adapted to connect the one end of the suspended portion to a lowermost slat among the plurality of slats in the opening portion, and, in a state in which the opening portion is completely closed, another suspended portion of the weight suspended from the rotating body may have a mass which is equivalent to or greater than a mass (weight) of the one suspended portion of the weight suspended from the rotating body. Still further, one end of the other suspended portion of the weight suspended from the weight may be formed as a free end. 
     The opening/closing apparatus for an opening portion in accordance with the present invention is a shutter apparatus or a window blind apparatus, and in the case of the shutter apparatus, it may be disposed in an opening portion of a building such as an entrance, while in the case of the window blind apparatus, it may be disposed in an opening portion of a building such as a window. 
     Advantages of the Invention 
     According to the invention, it is possible to provide an opening/closing apparatus for an opening portion which can be configured to be capable of overcoming the difficulty in manual operation by the operator, and which can also be configured to make it possible to perform a specific opening and closing operation of the opening portion by the plurality of slats through a specific manual operation by the operator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an explanatory perspective view of a preferred embodiment of the invention; 
         FIG. 2  is an explanatory partial cross-sectional side view of the embodiment shown in  FIG. 1 ; 
         FIG. 3  is an explanatory cross-sectional plan view of a portion shown in  FIG. 1 ; 
         FIG. 4  is an explanatory partial cross-sectional front view of the embodiment shown in  FIG. 1 ; 
         FIG. 5  is an explanatory partial enlarged perspective view of the embodiment shown in  FIG. 1 ; 
         FIG. 6  is an explanatory partial enlarged cross-sectional side view of the embodiment shown in  FIG. 1 ; 
         FIG. 7  is an explanatory partial enlarged cross-sectional side view of the embodiment shown in  FIG. 1 ; 
         FIG. 8  is an explanatory diagram of a tilting mechanism and a suspending mechanism of the embodiment shown in  FIG. 1 ; 
         FIG. 9  is an explanatory partial enlarged cross-sectional side view of the embodiment shown in  FIG. 1 ; 
         FIG. 10  is an explanatory partial enlarged cross-sectional side view of the embodiment shown in  FIG. 1 ; 
         FIG. 11  is an explanatory partial enlarged cross-sectional front view of the embodiment shown in  FIG. 1 ; 
         FIG. 12  is an explanatory partial fragmentary perspective view of the embodiment shown in  FIG. 1 ; 
         FIG. 13  is an explanatory partial enlarged side view of a raising and lowering mechanism of the embodiment shown in  FIG. 1 ; 
         FIG. 14  is an explanatory partial enlarged side view of the raising and lowering mechanism of the embodiment shown in  FIG. 1 ; 
         FIG. 15  is an explanatory partial enlarged front view of the raising and lowering mechanism of the embodiment shown in  FIG. 1 ; 
         FIG. 16  is a partial diagram explaining the operation of the raising and lowering mechanism of the embodiment shown in  FIG. 1 ; 
         FIG. 17  is a diagram explaining the operation of the tilting mechanism shown in  FIG. 8 ; 
         FIG. 18  is a diagram explaining the operation of the tilting mechanism shown in  FIG. 8 ; 
         FIG. 19  is a diagram explaining the operation of the tilting mechanism shown in  FIG. 8 ; 
         FIG. 20  is a diagram explaining the operation of the raising and lowering mechanism of the embodiment shown in  FIG. 1 ; 
         FIG. 21  is a diagram explaining the operation of the embodiment shown in  FIG. 1 ; 
         FIG. 22  is a diagram explaining the operation of the embodiment shown in  FIG. 1 ; 
         FIG. 23  is an explanatory view of another preferred embodiment of the invention; and 
         FIG. 24  is an explanatory view of still another preferred embodiment of the invention. 
     
    
    
     MODE FOR CARRYING OUT THE INVENTION 
     Next, a more detailed description will be given of the mode for carrying out the invention on the basis of the preferred embodiments illustrated in the drawings. It should be noted that the present invention is not limited to these embodiments. 
     EMBODIMENTS 
     In  FIGS. 1 to 15 , a window blind apparatus  1  in accordance with this embodiment is comprised of a frame body  3  which is disposed in an opening portion  2  of a building such as a window; a plurality of slats  4  which are juxtaposed to each other in a vertical direction V in the opening portion  2  surrounded by the frame body  3  and which opens and closes the opening portion  2 ; a link mechanism  5  serving as a connecting mechanism for mutually connecting the slats  4  adjacent to each other in the vertical direction V among the plurality of slats  4 ; a raising and lowering mechanism  9  which has a suspending mechanism  7  for suspending from the frame body  3  an uppermost slat  6  among the plurality of slats  4  connected by the link mechanism  5 , and which raises and lowers the plurality of slats  4  in opening and closing the opening portion  2 , by raising the slats  4 , starting with a lowermost slat  8  among the plurality of slats  4 , and by lowering the slats  4 , starting with that lowermost slat  8 , so as to open and close the opening portion  2  by the plurality of slats  4  connected by the link mechanism  5 ; a reaction force generating mechanism  10  for imparting to the raising and lowering mechanism  9  a reaction force which is oriented in a direction opposite to the direction of the load of the slats  4  in the opening portion  2  and which increases or decreases in correspondence with an increase or decrease of the load of the slats  4  in the opening portion  2  corresponding to the number of the slats  4  being raised or lowered by the raising and lowering mechanism  9  in the opening portion  2 ; and a tilting mechanism  11  for tilting the plurality of slats  4  in the raising and lowering of the plurality of slats  4  by the raising and lowering mechanism  9 . 
     The frame body  3  includes a pair of vertical frames  15  and  16  juxtaposed to each other, an upper frame  17  disposed in such a manner as to bridge upper portions of the vertical frames  15  and  16 , and a lower frame  19  disposed in such a manner as to bridge lower portions of the vertical frames  15  and  16 . 
     The vertical frame  15 , which is formed in the same way as the vertical frame  16 , is integrally formed by including an outer side wall portion  21 , an inner side wall portion  22  disposed in face-to-face relation to the outer side wall portion  21 , and a front wall portion  23  and a rear wall portion  24  disposed in such a manner as to bridge the outer side wall portion  21  and the inner side wall portion  22  and oppose each other. The outer side wall portion  21  has a side wall plate portion  25  and three pairs of holding wall portions  29 ,  30 , and  31  which are formed integrally with the side wall plate portion  25  and define three holding grooves  26 ,  27 , and  28  extending in the vertical direction V. The inner side wall portion  22  has a slit  32  extending in the vertical direction V. 
     The upper fame  17  includes a roof portion  36  integrally having a rear plate portion  35 , a pair of side plate portions  37  attached to the roof portion  36  and the respective outer side wall portions  21  of the vertical frames  15  and  16 , and a latticed front wall portion  38  suspended from a front portion of the roof portion  36  in such a manner as to bridge the pair of side plate portions  37  below the roof portion  36 . 
     Each of the slats  4  includes a slat body  41  and an attachment  43  for attaching one longitudinal end portion  42  of the slat body  41  to the link mechanism  5 . Each attachment  43  is fixed at one end to the end portion  42  of the corresponding slat body  41  through a fastener  44 , and projects at the other end through the slit  32  into the vertical frame  15 . 
     The link mechanism  5  includes a plurality of front edge link members  51  which are rotatably connected to each other through shaft members  50  and are foldable; a plurality of rear edge link members  53  which are rotatably connected to each other through shaft members  52  and are foldable; uppermost and lowermost transverse members  55  which are rotatably connected to upper end portions of the uppermost front edge link member  51  and rear edge link member  53  and to lower end portions of the lowermost front edge link member  51  and rear edge link member  53 , respectively, through shaft members  54 ; transverse members  55  which are respectively rotatably connected to every other shaft member  50  and  52  on the front edge link member  51  side and the rear edge link member  53  side, to a substantially central portion of which the other end of a corresponding attachment  43  projecting into the vertical frame  15  through the slit  32  is secured; and bent portions  56  which are integrally formed on respective ones of every other front edge link member  51  and rear edge link member  53  so as to determine respective folding directions of the plurality of front edge link members  51  and the rear edge link members  53  which are respectively rotatably connected to each other through the shaft members  50  and  52 . 
     In the raising of the lowermost front edge link member  51 , adjacent ones of the front edge link members  51  which are rotatably connected to each other by the shaft members  50  with the transverse members  55  not connected thereto are adapted to be folded by being restricted by the bent portions  56  such that the shaft members  50  are directed toward the rear wall portion  24 . Similarly, in the raising of the lowermost rear edge link member  53 , adjacent ones of the rear edge link members  53  which are rotatably connected to each other by the shaft members  52  with the transverse members  55  not connected thereto are adapted to be folded by being restricted by the bent portions  56  such that the shaft members  52  are directed toward the front wall portion  23 . The folded front edge link members  51  and rear edge link members  53  are adapted to be alternately positioned in the vertical direction V. 
     The suspending mechanism  7  includes a suspending plate  62  secured to a swingable member  61  of the tilting mechanism  11  in an upper portion of the vertical frame  15 ; a flexible cord-like member  66 , such as a wire, a rope, or a belt, which is rotatably connected at one end to a shaft member  64  at a distal end portion of one arm portion  63  of the suspending plate  62 , and is rotatably connected at the other end to the shaft member  54  at an upper end portion of the uppermost front edge link member  51 , which serves as one end portion  65  of the uppermost link mechanism  5 ; and a flexible cord-like member  70 , such as a wire, a rope, or a belt, which is rotatably connected at one end to a shaft member  68  at a distal end portion of the other arm portion  67  of the suspending plate  62 , and is rotatably connected at the other end to the shaft member  54  at an upper end portion of the uppermost rear edge link member  53 , which serves as the other end portion  69  of the uppermost link mechanism  5 . The swingable member  61  is swingably (rotatably) attached to a rotating shaft  82  of the raising and lowering mechanism  9 , and the rotating shaft  82  is rotatably supported at both ends by a pair of bearing plates  81  respectively mounted on the outer side wall portions  21  of the vertical frames  15  and  16 . Thus, the suspending mechanism  7  is adapted to allow the uppermost slat  6  among the plurality of slats  4  connected by the link mechanism  5  to be suspended from the frame body  3  through the cord-like members  66  and  70 , the swingable member  61 , the rotating shaft  82 , and the bearing plates  81 . 
     The raising and lowering mechanism  9  includes an ended chain  73  serving as a flexible elongated member which has ends  71  and  72  on both sides and is held in an undeflected manner; a traveling mechanism  74  for causing the chain  73  to travel in one direction A and the other direction B which is an opposite direction to the one direction A; and a transmitting mechanism  75  for transmitting the traveling of the one end  71  of the chain  73  in the directions A and B to the lowermost slat  8 . 
     The traveling mechanism  74  includes a sprocket wheel  76  serving as a rotating body around which the chain  73  is wound and which causes the chain  73  to travel as the sprocket wheel  76  rotates, and a rotational force imparting mechanism  77  for imparting a rotational force to the sprocket wheel  76  to rotate the sprocket wheel  76 . 
     The traveling mechanism  74  is adapted to cause the chain  73  to travel in the directions A and B by the rotation of the sprocket wheel  76  due to the rotational force imparted thereto. 
     The rotational force imparting mechanism  77  includes the rotating shaft  82  which is rotatably supported at both ends by the pair of bearing plates  81  respectively mounted on the outer side wall portions  21  of the vertical frames  15  and  16 , and to which the sprocket wheel  76  is secured; a wheel  83  for a ball chain which is secured to the rotating shaft  82  on the vertical frame  15  side; an endless ball chain  84  which is wound around the wheel  83 , is suspended on the indoor side of the building, and can be manually caused to travel; and an unillustrated known ratchet mechanism for temporarily inhibiting the traveling of the ball chain  84  by the manual operation of the ball chain  84 . 
     The rotational force imparting mechanism  77  is adapted to cause the rotating shaft  82  mounted rotatably on the respective outer side wall portions  21  of the vertical frames  15  and  16  via the bearing plates  81  to rotate by the imparting of the rotational force to the wheel  83  due to the traveling of the ball chain  84  by the manual operation of the ball chain  84 , to thereby impart the rotational force to the sprocket wheel  76  by the rotation of the rotating shaft  82 . 
     The chain  73  at one suspended portion  86  thereof suspended from the sprocket wheel  76  and having the one end  71  is partially disposed in the holding groove  26  movably in the directions A and B, while the chain  73  at the other suspended portion  87  thereof suspended from the sprocket wheel  76  and having the one end  72  is partially disposed in the holding groove  27  movably in the directions A and B. The chain  73  at a wound-around portion  88  thereof wound around the sprocket wheel  76  is disposed movably in the directions A and B in a holding passage  90  between the sprocket wheel  76  and a holding member  89  mounted on the bearing plate  81 . The deflection of the chain  73  is prevented by the holding wall portions  29  and  30  and the holding member  89  respectively forming the holding grooves  26  and  27  and the holding passage  90 . Thus, the chain  73  is held in an undeflected state by the holding wall portions  29  and  30  and the holding member  89 . 
     The transmitting mechanism  75  includes a traveling member  91  connected to the one end  71  of the chain  73  so as to travel in the directions A and B by the traveling of the chain  73  in the same directions A and B; a movable body  92  which is connected to the lowermost slat  8  by means of the lowermost transverse member  55  and the attachment  43 , and which is movable in the directions A and B; a rotating arm member  95  having one end  93  rotatably and linearly movably connected to the traveling member  91  and the other end  94  rotatably connected to the movable body  92 , so as to undergo rotation in an R 1  direction which allows the lowering of the traveling member  91  with respect to the movable body  92 ; and a torsion spring  96  serving as a resiliency imparting member for imparting to the rotating arm member  95  a resilient rotational force in an R 2  direction resisting the rotation of the rotating arm member  95  in the R 1  direction, so as to stop the lowering of the traveling member  91  with respect to the movable body  92 . 
     The traveling member  91  includes a main body portion  100  which is disposed in the holding groove  26  and fitted to the pair of holding wall portions  29 , and which is connected at an upper end portion thereof to the one end  71  of the chain  73  by means of a retainer  99  and a connector  98  having a pair of connecting pins  97 , so as to be movable in the directions A and B in the same way as the chain  73 ; and a pin  102  secured to a lower end portion of the main body portion  100  and having an enlarged head portion  101 . 
     The movable body  92  includes a linearly movable member  103  which is supported by the frame body  3  linearly movably in the directions A and B, and to which the other end  94  of the rotating arm member  95  is rotatably connected; a swingable member  105  connected to the lowermost slat  8  through the transverse member  55  and connected to the linearly movable member  103  through a shaft member  104  swingably in an R 3  direction and an R 4  direction; and a coil spring  106  serving as a resilient body and having one end connected to the linearly movable member  103  and the other end connected to the swingable member  105 . 
     The linearly movable member  103  includes a main body  111  disposed between the holding wall portions  29  and  30  and extending in the vertical direction V; a rolling roller  112  which is fitted to an upper portion of the main body  111  and is rollably brought into contact with the pair of holding wall portions  30 ; a rolling roller  113  which is fitted to a lower portion of the main body  111  and is rollably brought into contact with the side wall plate portion  25 ; a pin  114  which is provided on the main body  111  between the rolling rollers  112  and  113 , and to which the other end  94  of the rotating arm member  95  is rotatably fitted; a contact portion  115  formed on the main body  111  above the rotating arm member  95  so as to restrict by contact the rotation of the rotating arm member  95  in the R 2  direction by more than a predetermined amount; a support  118  secured to a lower portion of the main body  111  through screws  117  and adapted to swingably support the swingable member  105 ; and a contact portion  116  formed on the support  118  below the rotating arm member  95  so as to restrict by contact the rotation of the rotating arm member  95  in the R 1  direction by more than a predetermined amount. The support  118  is provided with the shaft member  104  and a pin  119  which is disposed in a slit  121 . 
     The swingable member  105  includes a main body portion  122  which has the slit  121  of a circular arc shape with an end portion of the pin  119  disposed therein and to which the other end of the coil spring  106  is connected, as well as a turned-back portion  123  which is integrally formed with the main body portion  122  and is turned back. 
     The swingable member  105  is swingably attached at the main body portion  122  thereof to the support  118  of the linearly movable member  103  through the shaft member  104 . The swingable member  105  is rotatably connected at one end of the main body portion  122  to a lower end portion of the lowermost front edge link member  51  and to one end portion of the lowermost transverse member  55  through the shaft member  54 . The swingable member  105  is rotatably connected at one end of the turned-back portion  123  to a lower end portion of the lowermost rear edge link member  53  and to the other end portion of the lowermost transverse member  55  through the shaft member  54 . 
     The coil spring  106  resiliently pulls the swingable member  105  to rotate the swingable member  105  about the shaft member  104  secured to the support  118 , such that the swingable member  105  is set in an initial swinging position, i.e., in a position where the slat  4  is rotated in the R 3  direction to a horizontal state, as shown in  FIGS. 5 and 6 , without being rotated in the R 4  direction to a vertical state, as shown in  FIG. 22 . The swinging motion (rotation) of the swingable member  105  about the shaft member  104  is adapted to be guided by the movement of the pin  119  along the slit  121 , and the range of the swinging motion (rotation) of the swingable member  105  is restricted by both ends of the slit  121 . 
     An elongated hole  125 , in which the pin  102  is fitted rotatably and linearly movably along the longitudinal direction of the rotating arm member  95 , is formed in the one wide end  93  of the rotating arm member  95 . An enlarged hole portion  127 , into and from which the enlarged head portion  101  of the pin  102  can be inserted and withdrawn, is formed in an end portion  126  of the elongated hole  125  located on the other end  94  side of the rotating arm member  95 . The other end  94  of the rotating arm member  95  is connected to the pin  114  rotatably in the R 1  direction and the R 2  direction. 
     The rotating arm member  95  is disposed on the linearly movable member  103  such that, in the rotation of the rotating arm member  95  in the R 1  direction, the pin  102  of the traveling member  91  moves through the elongated hole  125  from the one end  93  side toward the other end  94  side of the rotating arm member  95  to an extent of not reaching the enlarged hole portion  127 , while, in the rotation of the rotating arm member  95  in the R 2  direction, the pin  102  of the traveling member  91  moves through the elongated hole  125  from the other end  94  side toward the one end  93  side of the rotating arm member  95 . 
     The torsion spring  96  wound around the pin  114  is retained at one end thereof to the rotating arm member  95  and at the other end thereof to the linearly movable member  103 . The torsion spring  96  is disposed so as to impart to the rotating arm member  95  a resilient rotational force in the R 2  direction resisting the rotation of the rotating arm member  95  in the R 1  direction. 
     The transmitting mechanism  75  may be provided with a stopper (not shown) which is attached to the frame body  3  so as to be brought into contact with a lower portion of the linearly movable member  103  in the closed state of the opening portion  2 . 
     In the transmitting mechanism  75  for connecting to the lowermost slat  8  the end  71  of the one suspended portion  86 , suspended from the sprocket wheel  76 , of the chain  73  serving as the elongated member wound around the sprocket wheel  76  serving as the rotating body, when, in the lowering of the lowermost slat  8  due to the traveling of the chain  73  in the direction B, the lowermost slat  8  has collided against a foreign object, e.g., a person, and the collision has made it impossible for the lowermost slat  8  to be lowered, the traveling member  91  is lowered relative to the movable body  92 . At the time of this lowering, the rotating arm member  95  rotates in the R 1  direction from the position shown in  FIG. 13  to the position shown in  FIG. 16  against the resiliency of the torsion spring  96 . Hence, the lowering of the traveling member  91  relative to the movable body  92  is stopped by the resilient rotational force of the torsion spring  96  in the R 2  direction which gradually increases. Therefore, in the event that an abnormality has occurred in which the lowering of the lowermost slat  8  is hampered, the transmitting mechanism  75  is adapted to resiliently prevent the lowering of the lowermost slat  8  by the rotation of the rotating arm member  95  against the resiliency of the torsion spring  96  owing to the relative displacement of the movable body  92  in the vertical direction V relative to the traveling member  91 . When a rotation in the R 1  direction by more than a predetermined amount has occurred to the rotating arm member  95 , the contact portion  116  is adapted to be brought into contact with the rotating arm member  95  to forcibly stop that rotation, thereby forcibly stopping the lowering of the traveling member  91  relative to the movable body  92 . In addition, even if the operation of the chain  73  is not stopped immediately and the chain  73  is caused to travel slightly further in the downward direction A although the opening portion  2  is completely closed and the aforementioned stopper has been brought into contact with the lower portion of the linearly movable member  103 , the rotating arm member  95  is adapted to be stopped while rotating in the same way as described above. In other words, the rotating arm member  95  itself, which is rotatably and linearly movably connected to the one end  71  of the chain  73  through the traveling member  91 , is adapted to rotate about the pin  114  against the resiliency of the torsion spring  96  and to linearly move relative to the traveling member  91  so as not to cause further downward movement of the movable body  92 . Therefore, disadvantages cease to occur such as those in which the wholly extended link mechanism  5  is further extended and the slats  4  set in the completely closed state are further tilted, thereby making it possible to avoid causing damage to the link mechanism  5  and the slats  4 . 
     In the state in which the transmitting mechanism  75  is disposed inside the frame body  3 , the enlarged head portion  101  of the pin  102  is not disposed in the enlarged hole portion  127  of the elongated hole  125 , so that the rotating arm member  95  does not come off the traveling member  91  unintentionally. In the state in which the traveling member  91  and the movable body  92  of the transmitting mechanism  75  are removed from within the frame body  3 , mutual positions of the traveling member  91  and the movable body  92  can be altered freely, so that the enlarged head portion  101  of the pin  102  can be easily inserted into and withdrawn from the enlarged hole portion  127  of the elongated hole  125 . 
     The raising and lowering mechanism  9  is adapted to raise and lower the lowermost slat  8  among the plurality of slats  4  through the transmitting mechanism  75  owing to the traveling of the chain  73  in the directions A and B by the rotation of the sprocket wheel  76  through the wheel  83  and the rotating shaft  82  due to the manual operation of the ball chain  84 , to thereby effect the raising and lowering, starting with the lowermost slat  8  among the plurality of slats  4 . In the raising and lowering mechanism  9 , the load in the direction B of the slats  4 , the front edge link members  51 , the rear edge link members  53 , the transverse members  55 , and the chain  73 , which increases or decreases according to the number of the slats  4  to be raised or lowered, the numbers of the front edge link members  51  and the rear edge link members  53  which are thereby folded and the transverse members  55  associated therewith, and the difference in length between the suspended portion  86  and the suspended portion  87  of the chain  73  which is made to travel, is applied to the one end  71  of the suspended portion  86  of the chain  73 . 
     The reaction force generating mechanism  10  includes a no-back chain  133  which serves as a flexible elongated weight and is connected at one end  131  through a connecting mechanism  132  to the one end  72  of the other suspended portion  87 , suspended from the sprocket wheel  76 , of the chain  73  wound around the sprocket wheel  76 ; and a supporting plate  135  serving as a supporting member for accommodating a moving portion  134  of the no-back chain  133  which moved in the direction B as the other suspended portion  87  of the chain  73  suspended from the sprocket wheel  76  travels in the same direction B, so as to support that moving portion  134 . 
     The connecting mechanism  132  includes a connecting plate  143  which is mounted by means of a pair of shaft pins  141 , i.e., chain elements, disposed at the one end  72  of the chain  73  and by means of a retainer  142  for the shaft pins  141 ; and a bobbin-like piece member  144  which is rotatably mounted on the connecting plate  143  and is disposed in the holding groove  28  movably in the directions A and B. Chain elements at the one end  131  of the no-back chain  133  are secured to the connecting plate  143 . 
     The no-back chain  133  consists of a row of chain elements in which chain elements serving as a plurality of weight elements having a mutually identical mass are rotatably connected to each other in series so as to be capable of being deflected (bent) only in one direction. The load of the chain elements of the no-back chain  133  is set to correspond to a total load combining the load of the slats  4 , the load of the front edge link members  51  and the rear edge link members  53 , and the load of the transverse members  55  associated therewith, which increases each time the chain elements are accommodated on the supporting plate  135  or drawn out from the supporting plate  135 , but load of the chain elements of the no-back chain  133  may be set by incorporating thereinto the load of the chain  73  corresponding to a difference in length between the suspended portion  86  and the suspended portion  87  of the chain  73  which increases or decreases. 
     The supporting plate  135  is secured at end portions thereof to the respective upper portions of the vertical frames  15  and  16  in such a manner to bridge those upper portions, and the chain elements at the other end  145  of the no-back chain  133 , which is adapted to be bendable only to one side, are secured to the supporting plate  135 . As the suspended portion  87  of the chain  73  suspended from the sprocket wheel  76  travels in the direction A, i.e., the downward direction, the moving portion  134  of the no-back chain  133  supported on the supporting plate  135  is adapted to be drawn out from the supporting plate  135 , so as to allow the support thereof on the supporting plate  135  to be gradually released. Thus, the reaction force generating mechanism  10  is adapted to allow the load in the direction A of a drawn-out portion  146  of the no-back chain  133  being drawn out from the supporting plate  135  to be imparted to the one end  72  of the chain  73  through the connecting mechanism  132  as a reaction force, acting in the direction A opposite to the direction B, to the load applied in the direction B to the one end  71  of the chain  73 , i.e., the load transmitted in the direction B to the one end  72  of the chain  73  through the chain  73 . 
     The tilting mechanism  11  includes the swingable member  61  which is provided on the rotating shaft  82  so as to be swingable (rotatable) about the rotating shaft  82  with respect to the rotating shaft  82  through a bearing  151  and which has a recess  152  and a projection  153 ; a projection  154  attached to the chain  73  and fitting in the recess  152  in the traveling of the chain  73  in the direction B; a latch member  156  which has a recess  155  and which, when the projection  154  is not fitted in the recess  152 , as shown in  FIGS. 8 and 17 , is engaged with the projection  153  at that recess  155  so as to be set in a swinging inhibiting state, shown in  FIG. 8 , to inhibit the swinging (rotation) of the swingable member  61  about the rotating shaft  82 , whereas, when the projection  154  is fitted in the recess  152 , as shown in  FIG. 18 , the latch member  156  is rotated by the projection  154  and cancels the engagement of the recess  155  with the projection  153 , so as to be set in a swinging allowing state, shown in  FIG. 18 , to allow the swinging of the swingable member  61 ; and a resilient means  157  for imparting resiliency to the latch member  156  so as to set the latch member  156  in the swinging motion inhibiting state. 
     The swingable member  61  is disposed concentrically with the sprocket wheel  76 . The latch member  156  having a pawl portion  161  (see  FIG. 17 ) at one end thereof is attached at the other end  162  thereof to a support plate  164  through a shaft member  163  rotatably about the shaft member  163 . The support plate  164  is attached to an upper end of the vertical frame  15  between the swingable member  61  and the sprocket wheel  76 . The resilient means  157  is constituted by a coil spring which is disposed with one end retained by the support plate  164 , the other end retained by the latch member  156 , and a central portion wound around the shaft member  163 , and the resilient means  157  imparts resiliency to the latch member  156  so as to rotate the latch member  156  about the shaft member  163  to thereby allow the pawl portion  161  to move toward the recess  152 . 
     The tilting mechanism  11  is configured as follows: As the chain  73  travels in the direction B, the projection  154  is fitted into the recess  152 , as shown in  FIG. 18 , to rotate the latch member  156  against the resiliency of the resilient means  157 , to thereby cancel the engagement of the projection  153  with the recess  155 . As a result of this cancellation, the swingable member  61  is swung in conjunction with the movement of the projection  154 , as shown in  FIG. 19 . The series of rear edge link members  53  are relatively raised with respect to the series of front edge link members  51  against the resiliency of the coil spring  106  by means of the cord-like member  70  which is pulled upward by this swinging motion. Meanwhile, the series of front edge link members  51  are relatively lowered with respect to the series of rear edge link members  53  by means of the cord-like member  66  which is lowered downward. The slats  4  are thus adapted to be synchronously tilted to a vertical state, as shown in  FIG. 22 , by means of the transverse members  55  which are connected to the front edge link members  51  and the rear edge link members  53  so as to close the opening portion  2  by the slats  4 . When the opening portion  2  is closed by the slats  4 , the swingable member  105  is swung in the R 4  direction from the position shown in  FIG. 14  to the position shown in  FIG. 20 . 
     The sprocket wheel on the vertical frame  16  side, which is constructed in the same way as the sprocket wheel  76 , is secured to the rotating shaft  82  extending from the vertical frame  15  to the vertical frame  16 , and, as for the window blind apparatus  1 , the vertical frame  16  side is constructed in the same way as the vertical frame  15  side. 
     In the above-described window blind apparatus  1 , in the state in which the plurality of slats  4  are tilted vertically so as to close the opening portion  2 , as shown in  FIG. 22 , the projection  154  provided on the chain  73  is disposed in the recess  152 , as shown in  FIG. 19 , such that the engagement between the projection  153  and the recess  155  is canceled, and the latch member  156  is brought into contact with an outer peripheral edge  165  of the swingable member  61  and thereby holds the swinging motion allowing state with respect to the swingable member  61 . In such a state, when the ball chain  84  is manually operated for traveling in one direction to rotate the sprocket wheel  76  by means of the wheel  83  and the rotating shaft  82 , and the chain  73  is rotated in the direction A by this rotation, the projection  154  also moves about the rotating shaft  82  in conjunction with the traveling of the chain  73  in the direction A, and the swingable member  61  is also rotated in the same direction by the movement of the projection  154 . This rotation of the swingable member  61  causes the uppermost front edge link member  51  and the series of lower front edge link members  51  connected below the uppermost front edge link member  51  to be relatively raised with respect to the series of rear edge link members  53  by means of the cord-like member  66 . Meanwhile, the uppermost rear edge link member  53  and the series of lower rear edge link members  53  connected below the uppermost rear edge link member  53  are relatively lowered with respect to the series of front edge link members  51  by means of the cord-like member  70  while being assisted by the resiliency of the coil spring  106 . As a result, the plurality of slats  4  are synchronously tilted and are set in the substantially horizontal state, as shown in  FIG. 21 . When the plurality of slats  4  are set in the substantially horizontal state, the swingable member  105  is swung in the R 3  direction from the position shown in  FIG. 20  to the position shown in  FIG. 14 . 
     When the chain  73  is further made to travel in the direction A, the projection  154  starts to be disengaged from the recess  152 . As the projection  154  is disengaged from the recess  152 , the latch member  156  is rotated about the shaft member  163  by the resiliency of the resilient means  157 , and the projection  153  and the recess  155  are engaged, as shown in  FIGS. 8 and 17 , which engagement hampers the rotation of the swingable member  61 . As the one end  71  of the chain  73  is raised by the further traveling of the chain  73  in the direction A, the lower front edge link members  51  and the rear edge link members  53  of the link mechanism  5  which is connected to the one end  71  of the chain  73  through the transmitting mechanism  75  start to be folded. As a result of this folding, the plurality of slats  4  connected by the link mechanism  5  are sequentially overlapped from below, as shown in  FIG. 21 , until all the plurality of slats  4  are raised and overlapped with each other. As the connecting plate  143  collides against the unillustrated stopper provided on the outer side wall portion  21 , the manual operation of the ball chain  84  with respect to traveling in one direction is inhibited, and the ratchet mechanism is actuated by the manual operation of the ball chain  84 , as required, to maintain the open state of the opening portion  2 . 
     In the traveling of the chain  73  in the direction A, the one end  131  of the no-back chain  133  connected to the one end  72  of the chain  73  through the connecting mechanism  132  is pulled by the one end  72  of the chain  73  and is hence made to travel in the same direction A. As a result, the moving portion  134  of the no-back chain  133  supported on the supporting plate  135  is drawn out from the supporting plate  135 , the load in the direction A of this drawn-out moving portion  134  is gradually applied to the one end  72  of the chain  73 , and the applied load of the direction A of the drawn-out portion  146  acts as a reaction force to the increasing load in the direction B of the slats  4 , the front edge link members  51 , the rear edge link members  53 , and the transverse members  55 . Thus, it becomes possible to assist the traveling of the chain  73  in the direction A and reduce the manual force with respect to the ball chain  84 , thereby making it possible to effect the opening of the opening portion  2  with a light manual operating force. 
     When the ratchet mechanism is released and the ball chain  84  is manually operated reversely to the above in the open state of the opening portion  2 , the chain  73  is made to travel in the direction B, and this traveling causes the folding to be sequentially canceled, starting with the upper front edge link members  51  and rear edge link members  53 , which start to be extended. As a result, the overlapping of the plurality of slats  4  is sequentially canceled, starting with the upper slats  4 . When all the link mechanism  5  is extended, and all the overlapping of the plurality of slats  4  is also canceled, the projection  154  passes through a guide wedge space  166  and is fitted into the recess  152 , as shown in  FIG. 18 . This fitting-in causes the projection  154  to rotate the latch member  156  against the resiliency of the resilient means  157  to thereby cancel the engagement of the projection  153  with the recess  155 . As a result of this cancellation, the swingable member  61  is rotated in conjunction with the movement of the projection  154 . The rear edge link members  53  are relatively raised with respect to the front edge link members  51  by means of the cord-like member  70  which is pulled in the upward direction A by this rotation. At the same time, the front edge link members  51  are relatively lowered with respect to the rear edge link members  53  by means of the cord-like member  66  which is lowered downward. The plurality of slats  4  are thus synchronously rotated, and the opening portion  2  is set in the closed state by the series of slats  4  which are tilted in the vertical direction, as shown in  FIG. 22 . Subsequently, as the connecting plate  143  collides against the unillustrated stopper provided on the outer side wall portion  21 , the manual operation of the ball chain  84  with respect to traveling in one direction is inhibited, and the ratchet mechanism is actuated by the manual operation of the ball chain  84 , as required, to maintain the closed state of the opening portion  2 . 
     Midway in the opening or closing of the opening portion  2 , if the traveling of the ball chain  84  is temporarily stopped by the ratchet mechanism, it is possible to effect half opening of the opening portion  2  by the plurality of slats  4 . 
     In the traveling of the chain  73  in the direction B, the one end  131  of the no-back chain  133  is made to travel in the same direction B by being pushed by the one end  72  of the chain  73 , with the result that the drawn-out portion  146  of the no-back chain  133  suspended from the supporting plate  135  is accommodated toward the supporting plate  135  and is sequentially supported on the supporting plate  135 . Hence, as the moving portion  134  is supported on the supporting plate  135 , the load in the direction A of the drawn-out portion  146  applied to the one end  72  of the chain  73  gradually decreases together with the decreasing load in the direction B of the slats  4 , the front edge link members  51 , the rear edge link members  53 , and the transverse members  55 . Thus, it becomes possible to effect the closing of the opening portion  2  with a light constant operating force without hampering the traveling of the chain  73  in the direction B and without affecting the manual force with respect to the ball chain  84 . 
     Thus, with the window blind apparatus  1  in accordance with this embodiment, the raising and lowering of the lowermost slat  8  in the vertical direction V by the raising and lowering mechanism  9  is adapted to be effected by the reaction force imparted from the reaction force generating mechanism  10  and by the raising and lowering force imparted to the raising and lowering mechanism  9  from outside by the ball chain  84  of the rotational force imparting mechanism  77 . As the other suspended portion  87  of the chain  73  suspended from the sprocket wheel  76  travels in the direction A, i.e., the downward direction, the moving portion  134  of the no-back chain  133  supported on the supporting plate  135  is drawn out from the supporting plate  135 , so that the support thereof on the supporting plate  135  is adapted to be gradually released. Thus, the reaction force generating mechanism  10  is adapted to allow the load of the drawn-out portion  146  being drawn out from the supporting plate  135  in the no-back chain  133  to be imparted to the raising and lowering mechanism  9  as a reaction force. Consequently, even if the number of the slats  4  being raised in the opening of the opening portion  2  by the plurality of slats  4  increases, the opening of the opening portion  2  by the plurality of slats  4  can be effected with a substantially constant manual operating force without enlarging the raising and lowering force imparted to the raising and lowering mechanism  9 , i.e., the operator&#39;s manual operating force with respect to the ball chain  84 , thereby making it possible to overcome the difficulty of manual operation by the operator. 
     In addition, in the window blind apparatus  1  in accordance with this embodiment, since the enlarged hole portion  127 , into and from which the enlarged head portion  101  of the pin  102  can be inserted and withdrawn, is formed in the end portion  126  of the elongated hole  125  located on the other end  94  side of the rotating arm member  95 , the rotating arm member  95  can be easily connected and disconnected, so that maintenance and inspection, in addition to fabrication and assembly, of the apparatus can be facilitated. 
     In the window blind apparatus  1 , the rotating arm member  95  is disposed such that, in the rotation in the R 1  direction, the pin  102  of the traveling member  91  moves through the elongated hole  125  from the one end  93  side toward the other end  94  side of the rotating arm member  95  to an extent of not reaching the enlarged hole portion  127 . Therefore, it is possible to eliminate the possibility of the pin  102  from coming off the enlarged hole portion  127  when the traveling member  91  is displaced in the vertical direction V with respect to the movable body  92  on the basis of the traveling of the chain  73 . Meanwhile, when the traveling member  91  and the movable body  92  are removed from the window blind apparatus  1 , as the enlarged head portion  101  of the pin  102  is withdrawn from or inserted into the enlarged hole portion  127  of the elongated hole  125 , it is possible to easily effect the connection and disconnection of the rotating arm member  95  with respect to the traveling member  91 . 
     Although, in the window blind apparatus  1  in accordance with the above-described embodiment, the reaction force generating mechanism  10  is configured by including the no-back chain  133  and the supporting plate  135 , the reaction force generating mechanism  10  may alternatively be configured by including another rotating body equivalent to the sprocket wheel  76  and a flexible elongated weight which is equivalent to the chain  73  or the no-back chain  133  and is wound around this other rotating body. In this case, the one end  71  of the one suspended portion  86 , suspended from the sprocket wheel  76 , of the chain  73  wound around the sprocket wheel  76  is connected to the lowermost slat  8  among the plurality of slats  4 , while one end of one suspended portion, suspended from the other rotating body, of the weight equivalent to the chain  73  or the no-back chain  133  and wound around the other rotating body is connected to the one end  72  of the other suspended portion  87 , suspended from the sprocket wheel  76 , of the chain  73  wound around the sprocket wheel  76 , while one end of the other suspended portion, suspended from the other rotating body, of the weight wound around the other rotating body is formed as a free end. Thus, the reaction force generating mechanism  10  may be so adapted that a difference between the load of the one suspended portion, suspended from the other rotating body, of the weight wound around the other rotating body and the load of the other suspended portion, suspended from the other rotating body, of the weight wound around the other rotating body is imparted to the raising and lowering mechanism  9  as a reaction force. 
     In addition, the window blind apparatus  1  is so adapted that the lowermost slat  8  in the vertical direction V among the plurality of slats  4  in the opening portion  2  is precedingly raised to open the opening portion  2 , while that lowermost slat  8  is precedingly lowered to close the opening portion  2 . However, as described in JP-A-2011-132806, the window blind apparatus may be may be configured as follows: The lowermost slat  8  among the plurality of slats is connected and fixed to the lower frame  19  of the frame body  3 , and in the open state of the opening portion  2 , the plurality of slats  4  are disposed in such a manner as to overlap with each other on the lower side of the opening portion  2 . At the time of closing the opening portion  2 , the opening portion  2  is closed by precedingly raising the uppermost slat  6  in the vertical direction V among the plurality of slats  4  overlapped with each other in the opening portion  2  and by consecutively raising the remaining lower slats  4  in a drawing manner through the link mechanism  5  as the uppermost slat  6  is raised, whereas, at the time of opening the opening portion  2 , the opening portion  2  is opened by precedingly lowering the aforementioned uppermost slat  6  and by consecutively lowering the remaining lower slats  4  in a drawing manner through the link mechanism  5  as the uppermost slat  6  is lowered. In such a window blind apparatus, the one suspended portion  86  of the chain  73  suspended from the sprocket wheel  76  also serves to perform the function of the above-described suspending mechanism  7 . 
     Further, instead of the link mechanism  5  which connects the respective longitudinal end portions  42  of the slat bodies  41  adjacent to each other in the vertical direction V and has the front edge link members  51 , the rear edge link members  53 , and the like, the connecting mechanism may be a kind of hinge mechanism configured in such a manner as to rotatably connect upper and lower longitudinal edges of the slat bodies  41  adjacent to each other in the vertical direction V and to be able to specify the alternate folding direction (rotating direction) of such mutually connected slat bodies  41 . In addition, as shown in  FIG. 23 , the opening/closing apparatus for an opening portion may be, instead of the window blind apparatus  1 , a shutter apparatus  173  in which the series of slats  4  constituted by the plurality of slat bodies  41  connected to each other by hinge mechanisms  171  of the above-described kind are folded and accommodated in the lower frame  19  of the frame body  3 , and the slat  4  at one of the series of the plurality of slats  4  folded and accommodated in such a lower frame  19  is connected to the one end  71  the one suspended portion  86 , suspended from the sprocket wheel  76 , of the chain  73  of the raising and lowering mechanism  9 . With this shutter apparatus  173  as well, the raising and lowering of the slats  4  in the vertical direction V is adapted to be effected by the reaction force imparted from the reaction force generating mechanism  10  and the raising and lowering force imparted to the raising and lowering mechanism  9  from outside by the ball chain  84  of the rotational force imparting mechanism  77 , and the tilting mechanism  11  can be omitted in such a shutter apparatus  173 . 
     As shown in  FIG. 24 , the opening/closing apparatus for an opening portion may be, instead of the shutter apparatus  173  shown in  FIG. 23 , a shutter apparatus  201  in which the opening portion  2  is adapted to be opened or closed by simultaneously raising or lowering the plurality of slats  4  in the opening portion  2 . The shutter apparatus  201 , which has the frame body  3  (see  FIG. 1 ) defining the opening portion  2  and the plurality of slats  4  in the same way as described above, includes a connecting mechanism  202  for connecting the slats  4  to each other, a rotatable winding member  203  for winding up the plurality of slats  4 , and a reaction force generating mechanism  204  for generating a reaction force which increases in correspondence with a change of the number of the slats  4  being raised in the opening portion  2  and is oriented in an opposite direction to the direction of the load of the slats  4  in the opening portion  2 . 
     The connecting mechanism  202  is constituted by a publicly known interlocking type connecting mechanism or overlapping type connecting mechanism which is known by interlocking type slats or overlapping type slats. Such a connecting mechanism  202  is adapted to inhibit the rotation of one slat  4  between the mutually connected adjacent pair of slats  4  in excess of approximately 180° with the connecting mechanism  202  of the other slat  4  as an axis and to allow the rotation of the other slat up to approximately 360°, thereby providing directionality to the bending of the mutually connected slats by more than approximately 180°. 
     The winding member  203  disposed inside the upper frame  17  between the vertical frames  15  and  16  is constituted by a cylindrical body mounted on the rotating shaft  82  rotatably in the directions A and B about an axis  206  of the rotating shaft  82 . The winding member  203  is adapted to consecutively wind up the plurality of slats  4  in the opening  2 , starting with the uppermost slat  6  side by the rotation in the direction A in the closing of the opening portion  2  and, meanwhile, to pay out the wound slats  4 , starting with the lowermost slat  8  side, to the opening portion  2  by the rotation in the direction B in the opening of the opening portion  2 . One edge of the uppermost slat  6  among the plurality of mutually connected slats  4  is secured to the winding member  203 . 
     The reaction force generating mechanism  204  disposed inside the vertical frame  15  includes a chain  211  serving as a flexible elongated weight capable of traveling; a sprocket wheel  212  serving as a rotating body around which the chain  211  is wound and is mounted on the rotating shaft  82  rotatably in the directions A and B so as to be rotated in the directions A and B as the chain  211  travels in the directions A and B; a connecting mechanism  214  which connects one end, i.e., a lower end, of one suspended portion  213  of the chain  211  suspended from the sprocket wheel  212  to the lowermost slat  8  among the plurality of slats  4  in the opening portion  2 , so as to transmit the movement in the directions A and B of the suspended portion  213  to the lowermost slat  8  among the plurality of slats  4  in the opening portion  2  and, meanwhile, to transmit the movement in the directions A and B of the plurality of slats  4  in the opening portion  2  to the suspended portion  213 ; and an inhibiting mechanism  216  for inhibiting unintentional deflection of the suspended portion  213  of the chain  211  and unintentional radial projection of a wound-around portion  215  of the chain  211  around the sprocket wheel  212 . 
     The chain  211  consists of a row of chain elements in which chain elements serving as a plurality of weight elements having a mutually identical mass are rotatably connected to each other in series. One end of the other suspended portion  221  of the chain  211  suspended from the sprocket wheel  212  is formed as a free end. In a state in which the opening portion  2  is completely closed by the plurality of slats  4 , the chain  211  is wound around the sprocket wheel  212  such that the suspended portion  221  has a length equivalent to the length of the suspended portion  213 . Thus, in the state in which the opening portion  2  is completely closed by the plurality of slats  4 , the chain  211  is adapted to not cause the movement of the suspended portion  213  and the suspended portion  221  in the directions A and B. 
     The sprocket wheel  212  mounted on the rotating shaft  81  rotatably in the directions A and B meshes with the chain  211  at the wound-around portion  215 . 
     The connecting mechanism  214  has a connecting rod  225  which has end secured to a lower end of the suspended portion  213  and the other end secured to a lateral end of the lowermost slat  8  among the plurality of slats  4  for closing the opening portion  2  and is passed through the slit  32 . The connecting mechanism  214  is adapted to transmit the manual lifting movement and lowering movement of the lowermost slat  8  among the plurality of slats  4  to the lower end of the suspended portion  213  and to transmit the movement of the suspended portion  213  in the directions A and B to the lowermost slat  8  among the plurality of slats  4 . 
     The inhibiting mechanism  216  has one guide plate  226  mounted on the outer side wall portion  21  by being disposed along the suspended portion  213  and the wound-around portion  215  and one guide plate  227  mounted on the outer side wall portion  21  by being disposed along the suspended portion  213  in such a manner as to sandwich the suspended portion  213  in cooperation with the guide plate  226 . The guide plates  226  and  227  opposed to each other with a gap therebetween forms a traveling path for the suspended portion  213  by that gap. The guide plates  226  opposed to each other with the gap therebetween and the sprocket wheel  212  form a traveling path for the wound-around portion  215  by that gap. The suspended portion  213  and the wound-around portion  215  of the chain  211  are adapted to be caused to travel and moved in the directions A and B while being guided and restricted by such traveling paths. 
     The reaction force generating mechanism  204  may be provided on the vertical frame  16  side as well. In addition, in the shutter apparatus  201  in accordance with this embodiment, unillustrated guiding and restricting members for restricting the displacement in the back-and-forth direction of both side ends of the plurality of slats  4  in the opening portion  2  and guiding the movement of the both side ends in the vertical direction V and for guiding the winding up of the plurality of slats  4  onto the winding member  203  are respectively provided on the inner side wall portions  22  of the vertical frames  15  and  16  and the upper frame  17  so that the plurality of mutually connected slats  4  in the opening portion  2  will not be deflected in the back-and-forth direction and the plurality of slats  4  wound around the winding member  203  will not bulge radially outwardly from the winding member  203  when the lowermost slat  8  among the plurality of slats  4  is lifted and raised manually and by the reaction force generating mechanism  204 . 
     With the above-described shutter apparatus  201 , when the lowermost slat  8  among the plurality of slats  4  for closing the opening portion  2  is manually lifted in the direction A in the state in which the opening portion  2  is completely closed by the plurality of slats  4 , the plurality of slats  4  in the opening portion  2  are simultaneously raised to gradually open the opening portion  2 . Simultaneously therewith, the lower end of the suspended portion  213  is also moved in the direction A through the connecting mechanism  214 , and the suspended portion  213  is thereby also made to travel in the direction A. As the sprocket wheel  212  rotates in the direction A in the traveling of the suspended portion  213  in the direction A, the suspended portion  221  is similarly moved in the direction A, and the one end side of the suspended portion  221 , which is a free end, starts to be stacked inside the lower frame  19 . When the one end side of the suspended portion  221 , i.e., the free end, thus starts to be stacked inside the lower frame  19  and, meanwhile, the lower end of the suspended portion  213  is moved in the direction A, the load in the direction A based on the mass of the suspended portion  221  becomes gradually larger as compared with the load in the direction B based on the mass of the suspended portion  213 . The force acting in the direction A based on this load difference which becomes gradually larger is transmitted through the connecting mechanism  214  to the lowermost slat  8  among the plurality of slats  4  for closing the opening portion  2 . Thus, the raising of the plurality of slats  4  in the opening portion  2  is adapted to be effected by the force generated by the reaction force generating mechanism  204  in the direction A on the basis of the increasing load difference, namely, the reaction force in the opposite direction to the load of the plurality of slats  4  in the opening portion  2 . 
     Further, with the shutter apparatus  201 , since the plurality of slats  4  in the opening portion  2  are wound up onto the winding member  203  at the same time as they are raised, the load of the plurality of slats  4  in the opening portion  2  becomes gradually smaller, with the result that the plurality of slats  4  in the opening portion  2  are quickly raised and are wound up onto the winding member  203  even if a large manual force is not applied to the lowermost slat  8  among the plurality of slats  4 , for example, allowing the opening portion  2  to be fully opened. The opening operation of the opening portion  2  is stopped by the collision of the connecting rod  225  against an unillustrated stop mechanism, and the open state of the opening portion  2  is thereby maintained. 
     If the lowermost slat  8  suspended from the winding member  203  among the plurality of slats  4  wound up around the winding member  203  is manually pulled downward in the direction B in the state in which the opening portion  2  is fully open, the lower end of the suspended portion  213  is pulled downward and moved in the direction B through the connecting mechanism  214 . As a result, the load in the direction A based on the mass of the suspended portion  221  becomes gradually smaller as compared with the load in the direction B based on the mass of the suspended portion  213 , while the lowering force in the direction B based on the increase in the number of the slats  4  paid out from the winding member  203  increases. Hence, the opening portion  2  can be brought to the closed state by the manual pulling down force in the direction B which is made gradually smaller owing to the decrease in the load in the direction A based on the mass of the suspended portion  221  and the increase in the lowering force in the direction B based on the increase in the number of the slats  4 . Finally, the opening portion  2  is completely closed as the lowermost slat  8  is brought into contact with the lower frame  19 . 
     As described above, according to the shutter apparatus  201 , it is possible to overcome the difficulty in the operator&#39;s manual operation in both the opening and closing of the opening portion  2 . 
     Although, in the shutter apparatus  201 , both of the winding member  203  and the sprocket wheel  212  are rotatably mounted on the rotating shaft  82 , one of the winding member  203  and the sprocket wheel  212  may be secured to the rotating shaft  81 , and the other one thereof may be rotatably mounted on the rotating shaft  81 . In this case, if the other one of the winding member  203  and the sprocket wheel  212  is mounted on the rotating shaft  82  with appropriate sliding friction, the rotation of one of the winding member  203  and the sprocket wheel  212  can be transmitted to the other one of the winding member  203  and the sprocket wheel  212  with a appropriate frictional force, making it possible to assist the rotation of the other one of the winding member  203  and the sprocket wheel  212 , and a difference between the amount of rotation of one of the winding member  203  and the sprocket wheel  212  and the amount of rotation of the other one of the winding member  203  and the sprocket wheel  212  can be favorably overcome by sliding between the rotating shaft  82  and the other one of the winding member  203  and the sprocket wheel  212 . 
     Furthermore, in the shutter apparatus  201 , in a case where both of the winding member  203  and the sprocket wheel  212  are rotatably mounted on the rotating shaft  82 , the rotating shaft  82  may be a fixed shaft secured to one end of each of the vertical frames  15  and  16 . Also, the chain  211  may be a row of chain elements in which chain elements having mutually different masses are connected in series in the order of the magnitude of mass, instead of the row of chain elements in which chain elements having a mutually identical mass are connected in series. Additionally, the suspended portion  221  may be shorter than the suspended portion  213  in the state in which the opening portion  2  is completely closed by the plurality of slats  4 . 
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
           1 : window blind apparatus 
           2 : opening portion 
           3 : frame body 
           4 ,  6 ,  8 : slat 
           5 : link mechanism 
           7 : suspending mechanism 
           9 : raising and lowering mechanism 
           10 : reaction force generating mechanism 
           11 : tilting mechanism 
           72 : one end 
           73 : chain 
           76 : sprocket wheel 
           86 ,  87 : suspended portion 
           131 : one end 
           132 : connecting mechanism 
           133 : no-back chain 
           134 : moving portion 
           135 : supporting plate