A sliding panel structure. The sliding panel structure includes a frame having an upper support track and a lower guide rail. At least one sliding panel is connected between the upper support track and the lower guide rail. The sliding panel includes a sliding panel pivot axis and an extension for riding in the lower guide rail. The extension prevents undesired pivoting of the sliding panel about the sliding panel pivot axis. A mutual attraction device is connected between the sliding panel and the frame with a first mutual attraction part connected to the frame and the second mutual attraction part connected to the sliding panel. A fulcrum is utilized for tilting the sliding panel whenever the first mutual attraction part engages the second mutual attraction part.

The present invention relates to door panel structures, and in particular, to door panel structures having sliding doors and pivoting doors. This application is a Continuation-in-Part (CIP) of U.S. application Ser. No. 12/912,716, filed Oct. 26, 2010 and issued as U.S. Pat. No. 8,806,807 on Aug. 19, 2014, which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Various types of track-suspended door structures are known. For example, U.S. Pat. No. 3,266,189 shows a typical power-operated arrangement. It is known to so arrange sliding doors that the doors can move not only in direction of a suspension track, for example in a straight line to and from each other, but additionally include panel members which are arranged for swinging movement transverse to the direction of sliding movement. Such additional swinging movement is desirable particularly in installations where a maximum panel opening is desired, for example to permit a large number of people to rapidly leave a building, or to provide an opening of increased width for vehicular traffic. Residential applications whereby the user desires maximum view and ventilation are also to be appreciated. However, sliding doors which are so arranged cause difficulties since swinging movement of the door panels or door elements of sliding doors does not permit attaching of hinges about which the doors can swing to a fixed frame. The attachment point for the hinges are movable and for swinging movement the doors can no longer be supported along their width from the top. For example, the hinge attachment on a sliding frame portion will shift, causing the door, as it swings, to bind against a floor structure. It is customary to provide sliding doors with a downwardly projecting guide element, typically a bolt, or the like, which slides in a guide track or rail. This bolt, however, is movable longitudinally in a sliding direction and will shift its position upon release of a swinging door element from the sliding door structure, so that it is suspended only on the hinges, due to the force moment which the door exerts on the hinge structure. It is undesirable to foreshorten the door so that the tilting of the door frame, upon swinging movement of the door, is compensated, since, then, when the door is closed, a gap will permit exchange of heated or cooled air, and otherwise interfere with the purposes of a door, which is to close off an opening. 
     U.S. Pat. No. 4,438,594 uses a massive metal angle element to provide a pre-stressing force and keep the door panel from binding with the floor structure ort to counteract the weight as the panels swing open. This type of counterweight would add considerably to the weight of the door and require more strength to push the panel open or closed. Massive counterweights require reinforcements in the building frame and door jamb to hold the additional weight. A massive counterweight would require heavy duty bogies, guide tracks, and pivot hinges to carry the weight. Shipping would also be more expensive due to the additional weight. Installation of the door panels would require more manpower to hold up the “massive counterweight” while installers secure the panels to the bogies. The added shipping weight, manufacturing cost and labor would be cost prohibitive. 
     U.S. Pat. No. 5,272,839 uses a toothed apparatus and hinge pins to eliminate friction and weight transfer. The '839 patent also suggests a wing shaped bracket to prevent the pane from tilting. Brackets springs, and toothed apparatus require precision manufacturing and highly trained installers because the panels would need to be aligned perfectly. Toothed apparatuses and wing shaped brackets can wear out easily with repeated use. These disadvantages would add to the cost of manufacturing and installation as well as allowing for more points of failure in the closure. 
     Bi-folds closure, which are known and have been around since the 1950's. The Nana bi-fold doors manufactured by NanaWall Systems, Inc. or the lanai bi-fold doors, manufactured by Lanai Doors Incorporated, require four to eight hinge mechanisms per panel to stabilize and transfer the weight of the attached open panels to the frame of the building. These many hinges keep the panels from binding against a floor structure. These hinge mechanisms require precise manufacturing and installation because many of the panels are attached together like a train and a failure at one hinge or wheeled carriage bogie effects all the attached panels rendering the door inoperable. With many parts that need to be manufactured and assembled precisely and difficult installation, the costs for these bi-fold closure systems tend to be in the high end or Luxury category. More hinges also create more failure points for these bi-fold closures. Bi-fold closures are limited in their width due to the fact that the more panels that are attached together, the heavier the closure becomes and the harder it is for the consumer to push open a multi panel bi-fold closure because they need to move all the attached weight. 
     What is needed is a better sliding door structure. 
     SUMMARY OF THE INVENTION 
     The present invention provides a sliding panel structure. The sliding panel structure includes a frame having an upper support track and a lower guide rail. At least one sliding panel is connected between the upper support track and the lower guide rail. The sliding panel includes a sliding panel pivot axis and an extension for riding in the lower guide rail. The extension prevents undesired pivoting of the sliding panel about the sliding panel pivot axis. A mutual attraction device is connected between the sliding panel and the frame with a first mutual attraction part connected to the frame and the second mutual attraction part connected to the sliding panel. A fulcrum is utilized for tilting the sliding panel whenever the first mutual attraction part engages the second mutual attraction part. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1-1D  show a preferred embodiment of the present invention. 
         FIGS. 2A-2B  show the stationary door opened. 
         FIGS. 2C-2G  show the sliding door moving towards the stationary door. 
         FIG. 2H  shows the operation of the fulcrum. 
         FIGS. 3A-3B  show the first sliding door opened. 
         FIGS. 3C-3E  show the second sliding door moving towards the first sliding door. 
         FIG. 3F  shows the operation of the fulcrum on the second sliding door. 
         FIGS. 3G-3H  show the second sliding door opened. 
         FIG. 4  shows another preferred embodiment of the present invention. 
         FIGS. 5-6  show another preferred embodiment of the present invention. 
         FIGS. 7-9H  show another preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1 and 1A  show a right prospective and front view of sliding door structure  33 . Sliding door structure  33  is shown in the closed position and includes upper support track  110  and a lower guide rail  112 . In a preferred embodiment both upper support track  110  and lower guide rail  112  are aluminum extrusions. Upper support track  110  is preferably fastened to ceiling  24  and a lower guide rail  112  is preferably attached to floor  25 . Door jambs  118  are located as shown on both sides of sliding door structure  33 . Sliding door structure  33  preferably includes one stationary door  114  and two sliding doors  116 A and  116 B. The frames of doors  114 ,  116 B and  116 A are preferably constructed of aluminum extrusions. Also, preferably, panels  114  and  116  include an insulated glazing unit (not shown). 
     Sliding door structure  33  preferably utilizes dual point shoot bolt locking hardware  4  ( FIG. 1C ). Stationary door  114  is secured in the position shown in  FIGS. 1 and 1A  by the extension of shoot bolt  2  into upper support track  110  and the extension of shoot bolt  3  into lower guide rail  112  ( FIG. 1C ). As the user turns handle  120  forty-five degrees ( FIGS. 1B and 1D ), shoot bolts  2  and  3  are retracted. This disengages door  114  from upper support track  110  and lower guide rail  112  so that the door can be easily opened. 
     As shown in  FIGS. 2A and 2B  the user has pulled stationary door  114  so that it has pivoted 90 degrees and is opened. In  FIG. 2C  the user has grabbed retractable handle  5  and has pulled sliding door  116 A to the left with sufficient force to overcome the magnetic attraction of door magnets  6 . In a preferred embodiment, the magnetic attraction force between magnets  7  is greater than the magnetic attraction force between magnets  6 . Therefore, as the user pulls handle  5 , door  116 A moves leftward but door  116 B remains in place. 
     As shown in  FIGS. 2D ,  2 E and  2 F the user has pulled sliding door  116 A all the way leftward.  FIG. 2F  shows a close up perspective view of the tops of stationary door  114 , sliding door  116 A and upper support track  110 . 
     As shown in  FIG. 2F , upper pivot hinge  210  extends downward from stationary upper anchor  208 . Stationary door magnet  212  is housed inside stationary upper anchor  208 . Likewise, upper pivot hinge  216  extends downward from upper bogie  214 . Sliding door magnet  218  is attached to upper bogie  214 . Upper bogie  214  is supported by wheels  9 . Wheels  9  are configured to roll inside upper support track  110 , thereby allowing sliding door  116 A to slide leftward and rightward. 
     As shown in  FIG. 2F  stationary door  114  is pivoted 90 degrees open and sliding door  116 A has been slid toward stationary door  114  so as to engage stationary door magnet  212  with sliding door magnet  218 . Preferably magnets of an industrial strength and quality are utilized. 
       FIG. 2F  shows upper support track  110  having the approximate shape of an upside down “u” with flanges pointing inward toward the center and a grove running down the middle so that bogie  214  can run horizontally within upper support track  110 . Stationary door  114  is attached to stationary upper anchor  208  via fixed pivot hinge  210 . Preferably, stationary upper anchor  208  is fabricated from aluminum. 
       FIG. 2G  shows a close up perspective view of the bottom of stationary door  114 , sliding door  116 A and lower guide rail  112 . As shown in  FIG. 2G , lower pivot hinge  312  extends upward from bottom stationary anchor  310 . Likewise, lower pivot hinge  316  extends upward from lower bogie  314 . Lower bogie  314  is supported by wheels  9 . Wheels  9  are configured to roll inside lower guide rail  112 , thereby allowing sliding door  116 A to slide leftward and rightward. 
     Lower guide rail  112  has a cross section that is fabricated in the general shape of a “u” with flanges pointing inward toward the center and a grove running down the middle so lower pivot hinge  316  can run horizontally within the lower guide rail  112 . Lower bogie  314  is constructed similar to upper bogie  214 . 
     Roller  318  is attached to sliding door  116 A via axis  12 . Roller  318  includes center extension  11  that fits into groove  13  of lower guide rail  112 . Roller  318  is wider than the groove  13  and rides on the top of lower guide rail  112 . Preferably, roller  318  is made from a heavy duty convex nylon. Roller  318  is attached to sliding door  116 A in such a way as to enable sliding door  116 A to be slid horizontally left or right while keeping sliding door  116 A square in the closure. Center extension  11  holds sliding door  116 A parallel to upper support track  110  and lower guide rail  112  while sliding door  116 A is being slid leftward or rightward. 
     Fulcrum 
     As shown in  FIGS. 2G and 2H , fulcrum  311  is rigidly connected to stationary bottom anchor  310  so as to stop lower bogie  314  just before stationary door magnet  212  and sliding door magnet  218  are drawn together via magnetic force. Fulcrum  311  is installed in such a way as to work in unison with stationary door magnet  212  and sliding door magnet  218  and lower bogie  314  to tilt sliding door  116 A so as to lift center extension  11  clear of groove  13  of lower guide track  112  (see also  FIG. 2H ). 
     As shown in  FIGS. 3A and 3B , because extension  11  is clear of groove  13  ( FIG. 2H ), the user is able to pull on sliding door  116 A causing it to pivot about the axis formed by upper pivot hinge  216  ( FIG. 2F ) and lower pivot hinge  316  ( FIG. 2G ). 
     In  FIG. 3C  the user has grabbed retractable handle  5  of sliding door  116 B overcoming the magnetic attractive force of magnets  7 . 
     In  FIG. 3D , the user has pulled sliding door  116 B so that it is very close to opened sliding door  116 A. Extension  11  is inside groove  13  ( FIG. 2G ) of lower guide track  112 . 
     In  FIG. 3E , lower bogie  414  has made contact with fulcrum  311 . Inside upper support track  110  magnet  418  has not made contact with magnet  99 . However, the magnets are of sufficient strength and distance so that a magnetic force is drawing them together. 
     In  FIG. 3F , magnetic force has drawn magnet  418  and magnet  99  together. Fulcrum  311  has caused sliding door  116 B to pivot as shown so that extension  11  has cleared groove  13  ( FIG. 2G ) of lower track guide  112 . Now the user may easily open sliding door  116 B so that it can pivot about the axis formed by upper pivot hinge  416  and lower pivot hinge  516 , as shown in  FIGS. 3G and 3H . 
     Other Preferred Embodiments 
     Multiple Sliding Doors 
     The above described preferred embodiment showed a preferred embodiment having one stationary door  114  and two sliding doors  116 A and  116 B. It is possible to modify the present invention to include as many sliding doors as desired and to include another stationary door if desired. For example,  FIG. 4  shows sliding door structure  34  having stationary doors  201  and  202 . Sliding door structure  34  also has four sliding doors  203 ,  204 ,  205  and  206 . Doors  203  and  204  are configured to slide to the left and doors  205  and  206  are configured to slide to the right. 
     Windows 
     Although the above preferred embodiments described the present invention as being utilized for doors, it is also possible to utilize the present invention for other panel devices. For example,  FIG. 5  shows the utilization of the present invention for windows.  FIG. 5  shows stationary window  601  and sliding windows  602  and  603  mounted onto wall  701 . 
     In  FIG. 6 , the user has opened stationary window  601  and sliding window  602  in a fashion similar to that described above. The user has grabbed retractable handle  5  and is pulling sliding window  603  leftward. If the user desires, he can also open sliding window  603  by utilization of a fulcrum in a fashion similar to that described above. 
     Other Preferred Embodiment 
       FIGS. 7 and 7A  show a right prospective and front view of sliding door structure  433 . Sliding door structure  433  is shown in the closed position and includes upper support track  410  and a lower guide rail  412 . In a preferred embodiment both upper support track  410  and lower guide rail  412  are aluminum extrusions. Upper support track  410  is preferably fastened to ceiling  424  and a lower guide rail  412  is preferably attached to floor  425 . Door jambs  418  are located as shown on both sides of sliding door structure  433 . Sliding door structure  433  preferably includes one stationary door  414  and two sliding doors  416 A and  416 B. The frames of doors  414 ,  416 B and  416 A are preferably constructed of aluminum extrusions. Also, preferably, doors  414  and  416 B and  416 A include an insulated glazing unit (not shown). 
     Sliding door structure  433  preferably utilizes looking door latch  404  ( FIG. 7C ). Stationary door  414  is secured in the position shown in  FIGS. 7 and 7A  by the extension of locking bolt  421  into door  416 A. As the user turns handle  420  forty-five degrees ( FIGS. 7C and 7D ), locking bolt  421  is retracted. This disengages door  414  from door  416 A so that door  414  can be easily opened. 
     As shown in  FIGS. 8A and 8B  the user has pulled stationary door  414  so that it has pivoted 90 degrees and is opened. In  FIG. 8C  the user has grabbed handle  405  and has pulled sliding door  416 A to the left. It should be noted that handle  405  is also useful in providing the user with sufficient leverage to overcome the magnetic attraction between magnets  512  and  518  ( FIG. 8F ) when sliding the doors apart. 
     As shown in  FIGS. 8D ,  8 E and  8 F the user has pulled sliding door  416 A all the way leftward.  FIG. 8F  shows a close up perspective view of the tops of stationary door  414 , sliding door  416 A and upper support track  410 . 
     As shown in  FIG. 8F , upper pivot hinge  510  extends downward from stationary upper anchor  508 . Stationary door magnet  512  is housed inside stationary upper anchor  508 . Likewise, upper pivot hinge  516  extends downward from upper magnet holder  514  through slot  555 . Sliding door magnet  518  is attached to upper magnet holder  514 . 
     As shown in  FIG. 8F  stationary door  414  is pivoted 90 degrees open and sliding door  416 A has been slid toward stationary door  114  so as to engage stationary door magnet  512  with sliding door magnet  518 . Preferably magnets of an industrial strength and quality are utilized. 
       FIG. 8F  shows upper support track  410  having the approximate shape of an upside down “u” with flanges pointing inward toward the center and groove  555  running down the middle so that upper magnet holder  514  can run horizontally within upper support track  410 . Stationary door  414  is attached to stationary upper anchor  508  via fixed pivot hinge  510 . Preferably, stationary upper anchor  508  is preferably fabricated from aluminum. 
       FIG. 8G  shows a close up perspective view of the bottom of stationary door  414 , sliding door  416 A and lower guide rail  412 . As shown in  FIG. 8G , lower pivot hinge  612  extends upward from bottom stationary anchor  610 . Likewise, lower pivot hinge  616  extends upward from lower fulcrum contact piece  614 . Lower fulcrum contact piece  614  is slidable within slot  618 . 
     Lower guide rail  412  has a cross section that is fabricated in the general shape of a “u” with flanges pointing inward toward the center and groove  618  running down the middle so lower pivot hinge  616  can run horizontally within the lower guide rail  412 . 
     Rollers  618 A and  618 B are attached to sliding door  116 A via axes  312 . Roller  618 A includes center extension  311  that fits into groove  618  of lower guide rail  412 . Rollers  618 A and  618 B are wider than the groove  618  and both ride on the top of lower guide rail  412 . Preferably, rollers  618 A and  618 B are made from a heavy duty convex nylon. Rollers  618 A and  618 B are attached to sliding door  416 A in such a way as to enable sliding door  416 A to be slid horizontally left or right while keeping sliding door  416 A square in the closure. Center extension  311  holds sliding door  416 A parallel to upper support track  410  and lower guide rail  412  while sliding door  416 A is being slid leftward or rightward. 
     Fulcrum 
     As shown in  FIGS. 8G and 8H , fulcrum  611  is rigidly connected to stationary bottom anchor  610  so as to stop lower fulcrum contact piece  614  just before stationary door magnet  512  and sliding door magnet  518  ( FIG. 8F ) are drawn together via magnetic force. Fulcrum  611  is installed in such a way as to work in unison with stationary door magnet  512  and sliding door magnet  518  and lower fulcrum contact piece  614  to tilt sliding door  416 A so as to lift center extension  311  clear of groove  618  of lower guide track  412  (see also  FIG. 8H ). 
     In  FIG. 8I , the user has pulled downward on spring loaded door latch  473 . This clears latch  473  from slot  555  ( FIG. 8F ) and allows the user to swing door  416 A open. 
     As shown in  FIGS. 9A and 9B , because extension  311  is clear of groove  618  ( FIGS. 8G and 8H ) and latch  473  is clear from slot  555 , the user is able to pull on sliding door  416 A causing it to pivot about the axis formed by upper pivot hinge  516  ( FIG. 8F ) and lower pivot hinge  616  ( FIG. 8G ). 
     In  FIG. 9C  the user has grabbed handle  405  of sliding door  416 B and has pulled door  405  to the left. 
     In  FIG. 9D , the user has pulled sliding door  416 B so that it is very close to opened sliding door  416 A. Extension  311  is inside groove  618  ( FIG. 8G ) of lower guide track  412 . Latch  473  is riding in slot  555 . 
     In  FIG. 9E , lower fulcrum contact piece  714  has made contact with fulcrum  711 . Inside upper support track  410  magnet  718  has not made contact with magnet  799 . However, the magnets are of sufficient strength and distance so that a magnetic force is drawing them together. 
     In  FIG. 9F , magnetic force has drawn magnet  718  and magnet  799  together. Fulcrum  711  has caused sliding door  416 B to pivot as shown so that extension  311  has cleared groove  618  ( FIG. 8G ) of lower track guide  412 . The user has pulled downward on spring loaded door latch  473 . This clears latch  473  from slot  555  ( FIG. 8F ). Now the user may easily open sliding door  416 B so that it can pivot about the axis formed by upper pivot hinge  716  and lower pivot hinge  816 , as shown in  FIGS. 9G and 9H . 
     Tongue and Groove Door Connection 
       FIG. 9G  shows another preferred embodiment of the present invention. In  FIG. 9G , there is a press-fit tongue and groove connection between doors  416 A and  416 B and also between door  416 B and door jam  418 . As shown in  FIG. 9G , tongue  963  is press-fit into groove  964 . In  FIG. 9H , tongue  965  press-fits into groove  966 . For example, to slide doors  416 A and  416 B horizontally the user will grab handle  405   s  to overcome the friction force between the tongue and groove connections. The friction force is preferably greater between door  416 B and door jam  418 , than it is between doors  416 A and  416 B. 
     Although the above-preferred embodiments have been described with specificity, persons skilled in this art will recognize that many changes to the specific embodiments disclosed above could be made without departing from the spirit of the invention. For example, although the above preferred embodiments specifically disclose the utilization of magnetic force to attract the upper bogie to the upper anchor, it should be understood that a variety of other mutual attraction devices could also be utilized. For example, some of these include a rotating cam, a plethora of gears, a winged apparatus, a hook and latching pin, and a hollow cam and a solid cam that pivot and interlock. Also, although the above described preferred embodiments disclosed extension  11  attached to roller  318 , it is possible to utilize other extension types. For example any extension shape will work so long as it is able to clear grove  13  when the sliding door is tilted by the fulcrum. Also, although it was shown that upper bogie  214  and lower bogie  314  utilized wheels  9  for rolling, it is possible to omit the wheels and utilize bogies that slide within the upper support track and lower guide rail. Therefore, the attached claims and their legal equivalents should determine the scope of the invention.