Abstract:
A stay for opening and closing of a door does not become a hindrance when the door is open and is visually uncluttered. The stay has: a main body mounted to a housing; an arm having one end rotatably connected to the main body; a biasing element on the main body and biasing the arm so the arm rotates in at least one direction; an arm slider mounted to the arm and slidable in the longitudinal direction of the arm; and a mounting seat installed on the door and rotatably connected to the slider. As the slider is slidable relative to the arm and rotatable relative to the mounting seat installed on the door, an opening and closing force can be transmitted to the door from the one arm without requiring two links. Thus, the stay does not become a hindrance to a user and is visually uncluttered.

Description:
TECHNICAL FIELD 
     The present invention relates to a stay for opening and closing of a door, which is capable of facilitating an opening and closing operation of the door or a cover installed on a housing via a hinge in an openable and closable manner. 
     BACKGROUND ART 
     As a conventional stay for opening and closing of a door which facilitates an opening and closing operation of the door or a cover, there is known a stay having a slider crank mechanism  5  inside as illustrated in  FIGS. 12(   a ) and  12 ( b ) (see PL 1). A main body  1  of the stay is rotatably connected to an end  2   a  of an arm  2 . The main body  1  is mounted on a housing  6  and the arm  2  is connected to the door  7 . A force for assisting the opening and closing operation is transmitted to the door  7  from the arm  2 . 
     The main body  1  is provided with a coil spring  8 . An end of a link  3  is rotatably connected to a main-body slider  4  biased downward by the coil spring  8 . The other end of the link  3  is connected to a pivot base part of the arm  2 . These main-body slider  4 , link and arm  2  form the slider crank mechanism  5 . When the main-body slider  4  moves back and forth, the arm  2  equivalent to a crank rotates via the link  3 . Amounting seat  10  is rotatably mounted to the other end  2   b  of the arm  2  via another link  9 . The door  7  is attached to this mounting seat  10 . 
     As illustrated in  FIG. 12(   a ), when the door  7  is closed, a torque T 1  acts on the arm.  2  in a clockwise direction by a biasing force of the coil spring  8 . Thus, as the torque in the closing direction still acts on the closed door  7 , the closed state of the door can be kept stable. Meanwhile, as illustrated in  FIG. 12(   b ), when opening the closed door  7 , the arm  2  rotates and the slider crank mechanism  5  goes beyond a change point. Then, a torque T 2  acts on the arm  2  in a counterclockwise direction by the biasing force of the coil spring  8 . As the door  7  is further acted upon by the torque in the opening direction, the opening operation of the door  7  can be facilitated and the open angle of the door can be kept constant. 
     CITATION LIST 
     Patent Literature 
     PL 1: Japanese Patent No. 3120212 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in the conventional stay, two links (arm  2  and link  9 ) are required between the housing  6  and the door  7  in order to open and close the door smoothly. Then, as illustrated in  FIG. 12(   b ), when the door  7  is open, the two links are arranged in a line and juts out like a diagonal bracing between the housing  6  and the door  7 . Therefore, there arises a problem that when the door  7  gets open, the two links become hindrance to storage and are visually unpleasant. 
     The present invention solves such a problem of the conventional stay for opening and closing of a door and has an object to provide a stay for opening and closing of a door, which does not become a hindrance to a user when the door is open and is visually uncluttered. 
     Here, for example, the above-described stay for opening and closing of a door gives an additional force in the closing direction to a closed door and gives an additional force in the opening direction to the open door. When the door is heavy, it is necessary to give a great torque in the opening direction to the door in order to keep the attitude of the open door fixed. On the other hand, in order to reduce the operational feed when opening the closed door, it is necessary to reduce the torque in the closing direction given to the closed door. 
     However, the conventional stay has the following problem. If the spring force of the coil spring  8  is strengthened in order to keep the attitude of the open door fixed, it becomes difficult to give the closed door a small torque in the closing direction. On the other hand, if the spring force of the coil spring  8  is reduced in order to reduce the operational feel in opening the closed door, it becomes difficult to give a large torque in the opening direction to the open door. 
     Then, another object of the stay for opening and closing of a door of the present invention is to provide a stay for opening and closing of a door that is capable of freely controlling an opening and closing force transmitted to the door when opening and closing the door. 
     Solution to Problem 
     In order to solve the above-mentioned problems, one aspect of the present invention is a stay for opening and closing of a door, comprising: a main body mounted to a housing; an arm having one end rotatably connected to the main body; biasing means provided to the main body for biasing the arm so that the arm can rotate in at least one direction; an arm slider mounted to the arm so as to be slidable in a longitudinal direction of the arm; and a mounting seat installed on the door or cover and rotatably connected to the arm slider. 
     Another aspect of the present invention is a stay for opening and closing of a door, comprising: a main body mounted to a housing; an arm having one end rotatably connected to the main body; a main-body slider slidably provided on the main body and being biased in one direction by an elastic body; and a link rotatably connected to the main-body slider and the arm, wherein there are at least two pivots of the link relative to the arm or the main-body slider and when the link rotates, the pivots of the link relative to the arm or the main-body slider are changed from one pin to an opposite pin. 
     Advantageous Effects of Invention 
     According to the one aspect of the present invention, as the arm slider is provided slidable on the arm and the slide member can rotate relative to the mounting seat attached to the door, it is possible to transmit an opening and closing force to the door from one arm without requiring two links (arm and connecting link). Therefore, the obtained stay for opening and closing of a door does not become a hindrance to a user and is visually uncluttered. 
     According to the other aspect of the present invention, as the pins as pivot of the link are changed by rotating the link relative to the main-body slider or arm, it is possible to change at one stroke the biasing force of the elastic body transmitted from the main-body slider to the arm via the link. Therefore, it is possible to freely control the opening and closing force transmitted to the door when opening and closing the door. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is perspective view of a door and a housing on which is mounted a stay for opening and closing of a door according to a first embodiment of the present invention; 
         FIGS. 2(   a ) to  2 ( c ) are cross sectional views each illustrating relation between the open and closed state of the door and the operation of the stay; 
         FIG. 3  is a substantial part cross sectional view of the stay for opening and closing of the door; 
         FIG. 4  is an exploded perspective view of the stay for opening and closing of the door; 
         FIG. 5  is an exploded perspective view of an arm slider; 
         FIG. 6  is a cross sectional view of an arm and a slider; 
         FIGS. 7(   a ) and  7 ( b ) are cross sectional views of the arm installed on the door and the slider ( FIG. 7(   a ) illustrates a space provided between an arm main body and a friction plate and  FIG. 7(   b ) illustrates the arm main body and the frictional plate that are in close contact with each other); 
         FIGS. 8(   a ) to  8 ( c ) are operational views of a slider crank mechanism ( FIG. 8(   a ) illustrates the door in the open state,  FIG. 8(   b ) illustrates the slider crank mechanism that has reached a change point, and  FIG. 8(   c ) illustrates the door in the closed state); 
         FIGS. 9(   a ) and  9 ( b ) are views each illustrating a torque that acts on the arm by the slider crank mechanism in which the pins are changed ( FIG. 9(   a ) illustrates an example of the present embodiment and  FIG. 9(   b ) illustrates a comparative example); 
         FIG. 10  is a substantial part cross sectional view of a stay for opening and closing of a door according to a second embodiment of the present invention; 
         FIG. 11  is a substantial part cross sectional view of a stay for opening and closing of a door according to a third embodiment of the present invention; and 
         FIGS. 12(   a )  12 ( b ) are cross sectional views of a conventional stay for opening and closing of a door ( FIG. 12(   a ) illustrates the door in the closed state and  FIG. 12(   b ) illustrates the door in the open state). 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     With reference to the attached drawings, a stay for opening and closing of a door (hereinafter referred to as “stay”) according to the first embodiment of the present invention will be described in detail below.  FIG. 1  is a perspective view of a housing  11  and a door  12  on which the stay for opening and closing of a door is mounted. The stay has a main body  15  fixed to the housing  11  and an arm  14  connected to the door  12  side. The arm  14  is mounted to the main body  15  rotatable in the vertical plane. When opening and closing the door  12 , the arm  14  gives the door  12  a biasing force for assisting opening and closing of the door  12 . Between the housing  11  and the door  12 , a slid hinge  13  is mounted in addition to the stay. The rotation orbit of the door  12  is determined by the slide hinge  13 . Here, the slide hinge  13  is a well-known hinge which rotation axis moves when the door  12  gets open. As the rotation axis of the slide hinge  13  moves, when the door  12  gets open, the clearance between the frame of the housing  11  and the door  12  can be made smaller. 
     As illustrated in  FIG. 1 , a main body  15  of the stay is mounted on an upper part of a side plate  11   a  of the housing  11 . A side  11   a   1  at the ceiling side of the side plate  11   a  is orthogonal to a side  11   a   2  at the frame side and the main body  15  is mounted to be positioned at the corner of these sides. In the arm  14 , an arm slider  16  is mounted slidable in the longitudinal direction of the arm  14 . A mounting seat  17  is rotatably connected to the arm slider  16 . The door  12  is attached to this mounting seat  17 . 
     As illustrated in  FIGS. 2(   a ) to  2 ( c ), the arm  14  of the stay extends in approximately parallel to the door  12 . When opening and closing the door  12 , the arm  14  rotates relative to the main body  15  while it is kept in approximately parallel to the door  12 . As illustrated in  FIG. 12(   a ), when the door  12  is in the closed state, the arm  14  gives the door  12  an additional force in the closing direction. Therefore, the door  12  is kept stable in the closed state. As illustrated in  FIG. 2(   b ), when the closed door  12  gets open, for example, 20 degrees or more, then, the arm  14  gives the door  12  a force in the opening direction. This force of the arm  14  in the opening direction facilitates the opening operation of the door  12  and makes it possible to keep any open angle of the door fixed. As illustrated in  FIG. 2(   c ), the door  12  can open 90 degrees at the maximum. When closing the open door  12 , if the door  12  gets closed up to 20 degrees, for example, ( FIG. 2(   c ) to  FIG. 2(   b )), the door  12  closes automatically ( FIG. 2(   a )). In this embodiment, the door  12  is set out of the frame of the housing  11 , or it is provided to cover the frame of the housing  11 . 
       FIG. 3  is a substantial part cross sectional view of the stay and  FIG. 4  is an exploded perspective view of the stay. As illustrated in  FIG. 3 , the slider crank mechanism  21  is built in the main body  15 . The slider crank mechanism  21  has the arm  14 , a link  23  connected to an arm holding plate  22  of the arm  14 , and a main-body slider  24  provided at the main body  15  to be slidable in one direction. The weight of the door  12  is supported by the biasing force of a coil spring  25  as an elastic body contained in the main body  15 . In other words, the biasing force F 1  of the coil spring  25  is converted to a torque T 1  of the arm  14  by the main-body slider  24  and the link  23 . The weight of the door can be supported by the torque T 1  of the arm  14 . 
     As illustrated in  FIG. 2(   c ), when the door  12  is in the open state, the arm  14  is given a torque in the clockwise direction (in the opening direction of the door  12 ) by the biasing force of the coil spring  24 . When the door  12  gets closed, for example, 20 degrees or less, the slider crank mechanism reaches the change point. As illustrated in  FIG. 2(   a ), when the door  12  gets further closed, the arm  14  is given a torque in the counterclockwise direction (in the closing direction of the door  12 ) by the biasing force of the coil spring  25 . This torque can be used by a catch force of the closed door  12 . 
     As illustrated in  FIG. 4 , the main body  15  is combination of two-divided case half bodies  15   a  and  15   b . Each of the case half bodies  15   a  and  15   b  is formed by bending a thin plate. The case half bodies  15   a ,  15   b  have guide walls  27   a  and  27   b  jutting to the inside. In the guide walls  27   a  and  27   b , approximately box-shaped main-body slider  24  and spring receiver  28  are accommodated to be slidable in one direction along the guide walls  27   a  and  27   b . A pin P 1  as a pivot of the arm  14  is provided to run between the paired case half bodies  15   a  and  15   b . For improve the appearance, the main body  15  is covered with a decorated cover  29 . 
     An end of the arm  14  is rotatably connected to the main body  15  via the pin P 1 . The pin P 1  is a pivot of the arm relative to the main body  15 . The arm  14  has an elongating and hollow arm main body  30 , a pair of arm holding plates  22  mounted to an end of the arm main body  30  and a cylindrical bearing  19  provided between the paired arm holding plates  22 . 
     A cross section of the arm main body  30  is a flat box. At an end of the arm main body  30 , a mounting hole  30   a  is formed for mounting the paired arm holding plates  22 . Each of the paired arm holding plates  22  has a connecting part  22   a  elongating in accordance with the arm main body  30  and an enlarged part  22   b  which is enlarged relative to the connecting part  22   a . The connecting part  22   a  of each arm holding plate  22  is inserted to an end of the arm main body  30 . After the paired arm holding plates  22  and the arm main body  30  are connected to each other with the pin  18 , an end of the arm main body  30  is covered with a frame-shaped fixation piece. An end in the opposite direction of the arm main body  30  is covered with a plug  35 . 
     On the inner circumference of the bearing  19 , the pin P 1  is fit therein. Rotation of the arm  14  relative to the pin P 1  is guided by this bearing  19 . A link  23  is rotatably connected to the arm holding plates  22  via a pin P 2 . The pin P 2 , which is a pivot of the link  23  relative to the arm  14 , is positioned in the arm holding plates  22  to be shifted in a plane from the pin P 1  which is the pivot of the arm  14  relative to the main body  15 . 
     Between the main-body slider  24  and the spring receiver  28 , a plurality of coil springs  25  is accommodated. The plural coil springs  25  have one longitudinal ends inserted into plural cylindrical recesses of the main-body slider  24 . The other ends are into plural cylindrical recesses of the spring receiver  28 . The coil springs  25  are sandwiched between the main-body slider  24  and the spring receiver  28 . The main-body slider  24  and the spring receiver  28  are slidable in one direction by the guide walls  27   a  and  27   b  of the case half bodies  15   a  and  15   b . A pin P 5  for restricting sliding of the spring receiver  28  is provided to run between the paired case half bodies  15   a  and  15   b . In the spring receiver  28 , a long hole  28   a  is formed for insertion of the pin P 5 . By the coil spring  25 , the spring receiver  28  is acted upon by a biasing force in the right and back direction in the figure. Sliding in the right and back direction of the spring receiver  28  is restricted by the pin P 5 . Here, the main-body slider  24  and the spring receiver  28  take identical shapes. This is because a single die is used in injection molding of both of the main-body slider  24  and the spring receiver  28 . 
     At an end of the main-body slider  24 , a mountain-shaped projection  24   a  is formed. In this projection  24   a , a recess  24   b  and a long hole  24   c  are formed as two pin receivers corresponding to the two pins P 3  and P 4  of the link  23 . Out of the two pins, the pin P 4  is inserted into the long hole  24   c  and the other pin P 3  is fit in the recess  24   b.    
     The link  23  is combination of two parallel link plates connected by a bottom plate and has a U-shaped cross section. An end of the link  23  is rotatably connected to the arm holding plates  22  via the pin P 2 . At the other end of the link  23 , the above-mentioned two pins P 3  and P 4  are provided. 
     To the arm main body  30 , the arm slider  16  is mounted slidable in the longitudinal direction of the arm main body  30 . As illustrated in  FIG. 5 , the arm slider  16  has a frame-shaped slider main body  31  surrounding the arm main body  30 , a position adjusting screw  32  fit in the slider main body  31  and a friction plate  33  provided between the arm main body  30  and slider main body  31 . 
     In the slider main body  31 , a mountain-shaped projection  31   a  is formed. The mounting seat  17  is rotatably mounted to this projection  31   a  via a pin P 6 . The mounting seat  17  has a plate-shaped plate main body  17   a  and an approximately triangular projection plate  17   b  projecting downward from the plate main body  17   a . In the plate main body  17   a , a through hole  17   d  is formed for installing on the door  12 . In the projection plate  17   b , a hole  17   c  is formed for insertion of the pin P 6 . The mounting seat  17  rotates around the pin P 6 . 
     At the bottom of the slider main body, a female screw part  36  is fit therein. The female screw part  36  has a cylindrical female screw main body  36   a  having an inner circumference on which a female screw is formed and a square-shaped flange  36   b  provided integrally at the upper end of the female screw main body  36   a . As illustrated in  FIG. 6 , the female screw main body  36   a  of the female screw part  36  is fit in the hole  31   b  at the bottom of the slider main body  31 . The flange  36   b  of the female screw part  36  is placed on the upper surface of the bottom of the slider main body  31 . In the female screw part  36 , a position adjusting screw  32  is turned from the outside. The position adjusting screw  32  is cove red with a decorated plate  37  for improving the appearance and preventing the position adjusting screw  32  from turning carelessly. The decorated plate  37  is pressed and fixed to a hook  31   c  of the slider main body  31 . 
     The friction plate  33  is provided between the arm main body  30  and the slider main body  31 . The friction plate  33  is made of springy synthetic resin. On a contact surface of the friction plate  33  with the arm main body  30 , a one-step raised contact part  33   a  (see  FIG. 5 ) is formed. On a back surface of the friction plate  33 , a notch  33   b  is formed corresponding to the flange  36   b  of the female screw part  36 . As the flange  36   b  of the female screw part  36  is fit in the notch  33   b  of the friction plate  33 , the friction plate  33  is able to slide together with the slider main body  31 . 
     The friction plate  33  goes back and forth toward the arm main body  30  by the action of feed screw of the position adjusting screw  32 . By adjusting a contact pressure of the friction plate  33  with the arm main body  30 , the resistance when the slider main body  31  slides relative to the arm main body  30  is adjusted. As illustrated in  FIG. 7(   a ), in order to facilitate opening of the door  12 , a space is provided between the arm main body  30  and the friction plate  33 . On the other hand, as illustrated in  FIG. 7(   b ), in order to make it difficult to open the door  12 , the space between the arm main body  30  and the friction plate  33  is removed so that the arm main body  30  is in close contact with the friction plate  33 . 
     As illustrated in  FIG. 4  again, a damper  41  for generating a damping force by viscosity resistance of a fluid is build in the main body  15 . When the arm  14  rotates a predetermined angle or more, the arm  14  comes into contact with a movable part  42  of the damper  41  and the damper  41  is compressed. With compression of the damper  41 , a force of damping rotation is given to the arm  14 . As the damper  41  is provided, it is possible to reduce the impact of the door  12  when it gets closed and comes into collision with the housing  11 . 
     As illustrated in  FIGS. 8(   a ) to  8 ( c ), the arm  14 , the link  23  and the main-body slider  24  of the stay form the slider crank mechanism  21 . As illustrated in  FIG. 8(   a ), when the door  12  is open, the pin P 4  of the link  23  is fit at the right end of the long hole  24   c  of the main-body slider  24 . In this state, the pivot of the link  23  relative to the main-body slider  24  is the pin P 4 . The biasing force of the coil springs  25  contained in the main body  15  is transmitted, as a torque, via the pin P 4 , the link  23  and the pin P 2  to the arm  14  which is equivalent to a crank. When the door  12  is open, an additional torque in the opening direction of the door  12  acts on the arm  14 . 
     As illustrated in  FIG. 8(   b ), when the door  12  is rotated in the closing direction (the arm  14  is rotated in the counterclockwise direction relative to the main body  15 ), the slider crank mechanism  21  reaches the change point. In other words, the arm  14  can rotates both in the counterclockwise direction and in the clockwise direction, and the torque from the coil springs  25  is not transmitted to the arm  14 . 
     As illustrated in  FIG. 8(   c ), when the door  12  is further rotated in the closing direction (the arm  14  is further rotated in the counterclockwise direction relative to the main body  15 ), the slider crank mechanism goes beyond the change point and the torque in the closing direction of the door  12  acts on the arm  14  by the biasing force of the coil springs  25 . 
     In the stay using the slider crank mechanism  21  like in the present embodiment, the weight of the door  12  is supported by the biasing force of the coil springs  25 . Then, the biasing force of the coil springs  25  is also used in a catch force in the closing direction of the door  12  by using the change point of the slider crank mechanism  21 . When the door  12  is heavy, it is necessary to support the door  12  by strengthening the biasing force of the coil springs  25 . However, if the biasing force is strengthened, the catch force is strengthened thereby to increase the load of opening the door  12 . In order to prevent this, in the present embodiment, as illustrated in  FIGS. 8(   b ) and  8 ( c ), the pivot of the link  23  relative to the main-body slider  24  is changed from the pin P 4  to the pin P 3 . That is, as illustrated in  FIG. 8(   c ), when the link  23  rotates, the pin P 4  fit in the right end of the long hole  24   c  of the main-body slider  24  is lifted up and instead, the pin P 3  is fit in the recess  24   b  of the main-body slider  24 . Then, the pivot of the link  23  relative to the main-body slider  24  is changed from the pin P 4  to the pin P 3 . 
     As illustrated in  FIG. 9(   a ), a force F is transmitted from the link  23  to the arm  14  in a direction connecting the pin P 3  of the link  23  to the pin P 2 . The torque transmitted to the arm  14  is expressed by the force F×the arm length L. The arm length L′ is expressed by a distance from the pivot of the arm  14  (pin P 1 ) to the line L 1  connecting the pin P 3  and the pin P 2  of the link  23 . As the pin as pivot of the link  23  relative to the main-body slider  24  is changed from P 4  to P 3 , the arm length L′ can be shortened. This makes it possible to reduce the torque on the arm  14  and to reduce the catch force of the door  12  in the closed state. 
       FIG. 9(   b ) illustrates a comparative example when the pin is not changed. If the pin is not changed, the arm length L gets longer. Therefore, F×L cannot be reduced and the torque that acts on the arm  14  also cannot be reduced. 
       FIG. 10  is a substantial part cross sectional view of a stay for opening and closing of a door according to a second embodiment of the present invention. In this embodiment, like the stay for opening and closing of a door according to the first embodiment described above, a slider crank mechanism  52  is built in a main body  51 . The slider crank mechanism  52  has an arm  52 , a link  55  connected to arm holding plates  54  of the arm  53  and a main-body slider  56  provided on the main body  51  to be slidable in one direction. However, in the stay according to the second embodiment, two pins  57  are provided on the main-body slider  56  and two pin receivers  58  are provided on the link  55  corresponding to the two pins  57 , which is different from that in the stay according to the above-described first embodiment. The pivot of the link  55  is switched between the pins  57  by rotation of the link  55  relative to the main-body slider  56 , like in the above-described first embodiment. 
       FIG. 11  is a substantial part cross sectional view of a stay for opening and closing of a door according to a third embodiment of the present invention. In this embodiment, like the stay for opening and closing of a door according to the first embodiment described above, a slider crank mechanism  62  is built in a main body  61 . The slider crank mechanism  62  has an arm  62 , a link  65  connected to arm holding plates  64  of the arm  63  and a main-body slider  66  provided on the main body  61  to be slidable in one direction. However, in the stay according to the third embodiment, two pins  67  are provided on the arm holding plates  64  and two pin receivers  68  are provided on the link  65  corresponding to the two pins  67 , which is different from those in the stays according to the above-described first and second embodiments. The pivot of the link  65  is switched between the pins  67  by rotation of the link  65  relative to the arm holding plates  64 , like in the above-described first and second embodiments. 
     Here, the present invention is not limited to the above-described embodiments and may be embodied in various forms without departing from the scope of the present invention. For example, the direction of the torque that acts on the arm and the open and closed state of the door can be determined freely. Irrespective of the open and closed state of the door, the toque may always act in opening or closing direction. Besides, the torque in closing direction may act when the door is open, and the torque in opening direction may act when the door is closed. 
     Further, three or more pins may be provided as axes of rotation in the arm, link and main-body slider, or two pins may be provided in the arm and link or the link and main-body slider. 
     The present specification is based on Japanese Patent Applications No. 2009-045498 filed on Feb. 27, 2009, the entire contents of which are expressly incorporated by reference herein.
           11  . . . housing     12  . . . door     14 ,  53 ,  63  . . . arm     15 ,  51 ,  61  . . . main body     16  . . . arm slider     17  . . . mounting seat     23 ,  55 ,  65  . . . link     24   b  . . . recess (pin receiver)     24   c  . . . long hole (pin receiver)     24 ,  56 ,  66  . . . main-body slider     31  . . . slider main body     32  . . . position adjusting screw     33  . . . friction plate   P 1  to P 5  . . . pin