Patent Publication Number: US-8533909-B2

Title: Door opening and closing device

Description:
PRIORITY CLAIM 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2009-141667, filed Jun. 12, 2009, the entire contents of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to a door opening and closing device with a mechanism that connects door panels of a folding door together and automatically closes the door, and particularly relates to a door opening and closing device with excellent durability that can easily be attached or removed from the door panels. 
     BACKGROUND OF THE INVENTION 
     The space in lavatories of aircraft and the like is severely restricted, so lavatories are required to be as compact as possible. Therefore, doors are folding doors that do not require a large space in which to move. The folding doors mounted on these lavatories have a mechanism that automatically closes an open door in order to ensure safety and to block unpleasant odors (see Japanese Unexamined Patent Application Publication No. H7-11836). 
     The folding door of Japanese Unexamined Patent Application Publication No. H7-11836 uses coil springs in a door closing mechanism that automatically closes open doors. Conventionally, door closing mechanisms that automatically close open doors, such as the invention of Japanese Unexamined Patent Application Publication No. H7-11836, use coil springs as so-called torsion springs. As such, when opening or closing the door, stress accumulates around regions where helical wound wires formed at top and bottom ends of the coil springs is stretched straight, and thus the top and bottom ends of the coil springs are easily damaged, which has been a cause of reduced durability. Furthermore, there is a demand for a door opening and closing device that can be more easily attached and removed from the door panels. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a door opening and closing device with a mechanism having superior durability that can automatically close a door, and that can be easily attached to or removed from door panels of a folding door. 
     In order to achieve the aforementioned object, the door opening and closing device is provided with coil springs incorporated with a longitudinal direction orientated in a vertical direction into each of a top end part and a bottom end part of hinge pieces that rotatably connect the door panels of the folding door together; pin plates, having a portion thereof inserted into the coil springs in a top end part and a bottom end part of the coil springs so as to protrude in the longitudinal direction of the coil springs, attached to the coil springs; and brackets that fix the hinge pieces to the pin plate protruding from the top end part of the coil spring incorporated into the top end part of the hinge piece and to the pin plate protruding from the bottom end part of the coil spring incorporated into the bottom end part of the hinge piece; wherein the folding door is closed by a restoring force generated by a twisting of the coil springs. 
     Here, a specification wherein a shaft is inserted into each of the coil springs is also possible. It is also possible to have a specification with a shaft divided partway in the longitudinal direction. A top part of the divided shaft is connected to the pin plate that is inserted into the top end part of the coil spring, and a bottom part of the divided shaft is connected to the pin plate that is inserted into the bottom end part of the coil spring. A specification where the top part of the divided shaft and the bottom part of the divided shaft can move relatively to each other in a shaft axial direction is also possible. 
     With the present invention, the coil springs that function to automatically close the door are incorporated with the longitudinal direction oriented vertically in two locations, namely the top end part and the bottom end part of the hinge pieces that rotatably connect the door panels of a folding door together. Also, the door opening and closing device according to the present invention can be relatively easily attached to and removed from the door panels of the folding door because the pin plates have a portion thereof inserted into the coil springs and protrude out in the longitudinal direction of the coil springs in both the top end part and the bottom end part of the coil springs; are fixed to the coil springs; and the pin plate protruding from the top end part of the coil spring that is incorporated into the top end part of the hinge piece and the pin plate protruding from the bottom end part of the coil spring that is incorporated into the bottom end part of the hinge piece are attached to the hinge pieces by the brackets. 
     Furthermore, when the coil springs are twisted by opening and closing the door, the portions of the pin plates that are inserted into the coil springs are constricted at the top end part and the bottom end part of the coil springs by a tightening of the coil springs. Therefore, the coil springs corresponding to these portions are integrated with the pin plates and are supported by the pin plates, enabling occurrences of excessive stress concentration in the coil springs to be avoided. As a result, premature breaking of the coil springs due to repeated opening and closing of the door can be prevented, and durability can be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view illustrating a folding door. 
         FIG. 2  is a top plan view of the folding door of  FIG. 1 . 
         FIG. 3  is an explanatory diagram illustrating a process of attaching a door opening and closing device of the present invention. 
         FIG. 4  is an explanatory diagram illustrating an internal construction of the door opening and closing device of the present invention. 
         FIG. 5  is an explanatory diagram illustrating a process of inserting a pin plate into a coil spring. 
         FIG. 6  is an explanatory diagram illustrating an engagement condition between a pin plate and a coil spring. 
         FIG. 7  is an explanatory diagram illustrating an insert shaft mechanism. 
         FIG. 8  is an explanatory diagram illustrating a process of inserting an insert shaft into a coil spring. 
     
    
    
     DETAILED DESCRIPTION 
     The door opening and closing device of the present invention is described below based on embodiments shown in the figures. 
     As illustrated in  FIG. 1  and  FIG. 2 , a door opening and closing device  4  of the present invention is attached to a folding door  2  (hereinafter referred to as door  2 ) that is used on an aircraft lavatory  1 . Two door panels  2   a ,  2   b  that constitute the door  2  are connected by the door opening and closing device  4 . Each of the door panels  2   a ,  2   b  has a curved surface expanding outward in an arc shape. By forming the door panels  2   a ,  2   b  with outward-expanding curved surfaces, a large space can be secured inside of the door  2 . The present invention is not limited to the door panels  2   a ,  2   b  with curved surfaces, and can also be applied to flat door panels. 
     A guide shaft  3   a  inserted into a top surface of the first door panel  2   a  slides in left and right directions along a guide rail provided on a top edge of an attachment frame  16 , and a second door panel  2   b  has a construction that is axially supported by the top edge and a bottom edge of the attachment frame  16  by a rotating shaft  3   b.    
     The door opening and closing device  4  has hinge pieces  5   a ,  5   b  that are fixed to opposing side surfaces of the door panels  2   a ,  2   b . The hinge pieces  5   a ,  5   b  have a construction such that the top and bottom end parts thereof are mutually interlocked. Attachment holes  6   a ,  6   b  are formed in the mutually interlocked regions. 
     The hinge pieces  5   a ,  5   b  are assembled so that the attachment holes  6   a ,  6   b  are vertically aligned. Furthermore, as illustrated in  FIG. 3 , housings  12  that incorporate the coil springs  11  are made to pass through the attachment holes  6   a ,  6   b , and are attached to the hinge pieces  5   a ,  5   b . As the housings  12  incorporating the coil springs  11  are attached to the top end part and the bottom end part of the hinge pieces  5   a ,  5   b  in a similar fashion, a description of the housing  12  attached to the top end part will be serve to illustrate both. 
     As illustrated in  FIG. 4  through  FIG. 6 , the coil spring  11  into which the pin plates  10  are inserted in the top and bottom end parts is incorporated into the housing  12 . Elongate holes  10   a  and vertically extending engagement grooves  10   b  are formed in the pin plates  10 . The pin plates  10  are attached to the coil spring so that the engagement grooves  10   b  engage with the inner circumferential surface of the coil spring  11  with the elongate holes  10   a  protruding from the coil spring  11 . End surfaces of vertical ends of a helical wire that forms the coil spring  11  are constructed so as to be in contact with the surfaces of the pin plates  10  in order to lock to the coil spring  11  and the pin plates  10  together. 
     An outer diameter of the coil spring  11  is, for example, from approximately 9 mm to 15 mm, and a length is from approximately 100 mm to 120 mm. A length of the portion of the pin plates  10  inserted into the coil spring  11  (portion corresponding to the engagement grooves  10   b ) is, for example, from approximately 10 mm to 15 mm. 
     The portion of the elongate hole  10   a  of the pin plate  10  provided in the top end part of the coil spring  11  is inserted into slots  9   a  of a fitting  9 . The fitting  9  and the pin plate  10  are connected by a pin  9   b  that passes through the elongate hole  10   a . A cam  8  is interposed in a top part of this fitting  9 , and a bracket  7  is attached by a screw  7   a . In this manner, the pin plate  10  and the bracket  7  are integrated. The bracket  7  is fixed to the door panel  2   a  by a separate screw  7   b.    
     A fan shaped cutaway is formed in the cam  8 , and a cutaway is also formed in a top end part of the housing  12 . These cutaways are interlocked so that an angle of rotation of the cam  8  (door panels  2   a ,  2   b ) is restricted. 
     A portion of the elongate hole  10   a  of the pin plate  10  provided in the bottom end part of the coil spring  11  is similarly inserted into the slots  9   a  of the fitting  9 . Furthermore, the fitting  9  and the pin plate  10  are connected by a screw  9   c  that passes through the elongate hole  10   a  and the elongate hole  12   a  of the housing  12 . At this time for example, the fitting  9  of the bottom side (pin plate  10 ) is fixed to the housing  12  in a position that rotates 180 degrees around the coil axial center with respect to the top side fitting  9  (pin plate  10 ). 
     In this way, the housing  12  incorporating the coil spring  11  and the like is attached to the hinge pieces  5   a ,  5   b  with the attachment holes  6   a ,  6   b  in an aligned state. The bottom end part of the hinge pieces  5   a ,  5   b  also have the same construction, and herein, the pin plate  10  that is inserted into a bottom end part of the coil spring  11  is fixed to the hinge piece  5   a  by the bracket  7 . 
     When the first door panel  2   a  is pressed from the outside, the door panels  2   a ,  2   b  will rotate around the door opening and closing device  4 , and the door  2  will open. At this time, the coil springs  11  are twisted by the brackets  7  that are connected to the door panel  2   a . Thus, when pressure on the door panel  2   a  is released, the brackets  7  and the door panel  2   a  will return to their original positions due to of the restoring force of the twisted coil springs  11 , and the door  2  will automatically close. 
     To install the door opening and closing device  4  of the present invention to the door panels  2   a ,  2   b , the coil springs  11  with inserted pin plates  10  in the top and bottom end parts as described above need only be attached at two locations, namely the top end part and the bottom end part of the hinge pieces  5   a ,  5   b  and the corresponding brackets  7  affixed to the door panel  2   a , so the operation can be completed in a relatively few number of steps, with no complicated processes. Furthermore, to remove the door opening and closing device  4 , a procedure that is the reverse of the installation operation need only be performed, so the operation can be completed in a relatively few number of steps, with no complicated processes. As such, the components constituting the door opening and closing device  4 , such as the coil springs  11 , brackets  7 , and the like, can be quickly replaced. 
     In this embodiment, a unit that incorporates the coil springs  11 , the pin plates  10 , the fittings  9 , and the cam  8  in the housing  12  can simply be attached to the attachment holes  6   a ,  6   b  of the hinge pieces  5   a ,  5   b , further simplifying the installation process. 
     In the present invention, when the coil springs  11  are twisted by the opening and closing of the door  2 , the portions of the pin plates  10  that are inserted in the top end part and the bottom end part of the coil springs  11  (portions corresponding to the engagement grooves  10   b ) are constricted by the tightening coil springs  11 . Specifically, when the coil springs  11  are twisted by the pin plates  10  that are attached to the coil springs  11 , the tightening of the coil springs  11  will gradually proceed from the end parts toward a center part in an coil axial direction. 
     If both end parts of the coil springs  11  are twisted without the pin plates  10  inserted, excessive stress concentration will occur at both end parts of the coil springs  11 , the axial direction of the coil springs  11  will not be able to maintain a straight line, and warping or other effects will occur, leading to a risk of premature damage. In the present invention, the portions of the coil springs  11  that constrict the pin plates  10  are integrated with and supported by the pin plates  10 , thus preventing the accumulation of excessive stress in the coil springs  11 . Therefore, the occurrence of premature damage to the coil springs  11  due to repeated openings and closings of the door  2  will be reduced, thus improving durability. 
     As illustrated in  FIG. 7  and  FIG. 8 , an insert shaft  13  can be inserted into the coil springs  11 . In this embodiment, the insert shaft  13  has a construction such that it is divided into a top part of the divided shaft  14  and a bottom part of the divided shaft  15 . The top part of the divided shaft  14  has a protruding part  14   a  in a bottom end part and a cutaway part  14   b  in a top end part. The bottom part of the divided shaft  15  has a recessed part  15   a  in a top end part and a cutaway part  15   b  in a bottom end part. The protruding part  14   a  and the recessed part  15   a  are rotatably mated. 
     The pin plates  10  are inserted into the cutaway parts  14   b ,  15   b  of the top part of the divided shaft  14  and the bottom part of the divided shaft  15 , respectively, the top part of the divided shaft  14  is connected to the pin plate  10  that is inserted in the top end part of the coil spring  11 , and the bottom part of the divided shaft  15  is connected to the pin plate  10  that is inserted into the bottom end part of the coil spring  11 . The top part of the divided shaft  14  and the bottom part of the divided shaft  15  rotate relatively to each other around the shaft axis and can move along the shaft axial direction inside the coil springs  11 . 
     When the coil springs  11  are twisted due to the opening and closing of the door  2 , the coil springs  11  will constrict the insert shaft  13  in addition to the pin plates  10  due to the insert shaft  13  being inserted into the coil springs  11 . Thus, the coil springs  11  are supported by the pin plates  10  as well as the insert shaft  13 . Therefore, the stress generated in the coil springs  11  is dispersed across a wider region, and durability of the coil springs  11  can be further improved. 
     In order to effectively increase the durability of the coil springs  11 , an outer diameter of the insert shaft  13  is set, for example, within a range from approximately 85% to 90% of an inner diameter of the coil spring  11 . 
     As shown in  FIG. 8 , because the top part of the divided shaft  14  and the bottom part of the divided shaft  15  are connected to the pin plates  10 , when the pin plates  10  rotate due to the opening and closing of the door  2  (i.e. when the coil spring  11  is twisted), the top part of the divided shaft  14  and the bottom part of the divided shaft  15  will rotate in conjunction with the pin plates  10 . In this manner, the top part of the divided shaft  14  and the bottom part of the divided shaft  15  will rotate in the same direction as the twisted coil spring  11 , reducing the amount of friction between the top part of the divided shaft  14 , the bottom part of the divided shaft  15 , and the coil spring  11 . 
     Furthermore, the coil springs  11  shrink in length when twisted. Thus, if the top part of the divided shaft  14  and the bottom part of the divided shaft  15  are made so as to be able to move relatively to each other in the shaft axial direction, there will be no additional stress generated in the coil springs  11 , leading to even greater advantageousness for improving durability. 
     The door opening and closing device  4  of the present invention can be used for folding doors installed on lavatories of vehicles such as buses, trains, and ships and the like, in addition to being used in the folding door installed on the aircraft lavatory  1 . Furthermore, the present invention is not limited only to the lavatory  1 , but can also be used for folding doors installed in various locations such as residential unit bathrooms and the like.