Patent Abstract:
A retractable screen door for drawing a flexible screen panel across an opening, including a flexible screen wound around a spring biased take-up shaft, and guide rails for guiding the screen as it is moved across the opening. A unique latch mechanism is disclosed, said latch mechanism being located in the guide rails. Further, the screen may include an adjustable gear assembly for changing the tension on the spring. The retractable screen is optionally designed to have the appearance of a common door casing.

Full Description:
BACKGROUND OF THE INVENTION 
     This invention relates to door screens. More specifically, this invention relates to horizontally movable door screens rotatably mounted on a take-up shaft and capable of being rolled and unrolled from a vertically oriented storage member. 
     There are a number of examples in the prior art of rolling screens for use with doors. In general, these screens consist of a latch member and a vertically oriented take-up roll located in front of a door frame member. The latch member tends to be vertically oriented on the door frame member opposite the take-up roll. The take up roll has a screen rotatably mounted on it, which can be extended and retracted according to the users needs. Though functional, the prior art screens do have some significant problems. 
     The most common problem is that many screens are open at the upper and lower edges. With these designs the screen is only connected to the latch member and the take-up shaft, thus leaving the upper and lower portion of the screen open. This allows insects and other debris to enter the building through the screen, which decreases the effectiveness of the screen. 
     Some designs solve this problem by placing guide rails on the top and bottom of the door opening. The screen moves within these guide rails as it is extended across the opening, thus creating a better seal. However, the screen is easily dislodged from the typical guide rail. Minimal twisting of the screen as it is moved through the screen door assembly can cause the screen to be removed from the rails, thus making use of the screen more difficult. 
     Another problem comes with the latch mechanism for the screen. Latching a screen in place often involves time consuming steps. A typical screen will have either a handle or hook-and-eye latch mechanism. A handle latch will have a handle portion that locks within a latch portion. This can be done by placing a retainer mechanism, or latch portion, for the handle portion within a vertical member. The vertical member will be located on the opposite side of the opening from the take-up shaft. These latch mechanisms can be tedious to use and are prone to breaking. In addition, latching and unlatching these assemblies can be time consuming. 
     The hook-and-eye latch requires holes, or eyes, within the screen to be aligned with hooks located on the vertical member. The hooks, which operate as the latch portion, are then placed through the eyes to hold the screen in place. Again, this process can be tedious and time consuming. The inconvenience of aligning the hooks and eyes every time the screen must be closed discourages use of the screen. 
     A further problem with prior rolling screen designs is that there is no way for a user to easily adjust the winding speed of the screen. To change the speed at which the screen winds, the torque on an internal spring must be changed. To do this on most screens, the take-up shaft must be disassembled to gain access to the spring. Even if access is gained, there is often no mechanism for adjusting the tension of the spring within the take-up shaft. The process of changing the tension on the spring is too difficult for an average consumer to do, so as a practical matter the speed of winding can not be changed on a typical rolling screen. Additionally, on prior art screen doors it is possible to over tension the coil spring causing a dangerous high speed return of the handle portion. 
     Finally, most rolling screens require a large housing to conceal the take-up shaft and screen. The vertical members, if used, are much smaller than the take-up shaft housings, so the door opening will not be symmetrical. In addition, the large housing and vertical member are very different in size from normal door moldings, so they tend to make the building unattractive. If guide rails are used on the top and bottom, these again detract from the appearance of the door opening. The lower rail can also create a tripping hazard if it is unnoticed by a user. As a result of these problems, many people will choose not to use rolling screens for aesthetic and safety reasons. 
     SUMMARY OF INVENTION 
     The aforementioned problems are overcome by the present invention wherein a screen door is provided which includes a take-up shaft attached to an adjustable gear assembly for winding the spring, a screen rotatably wound on the take-up shaft, a screen case which encloses the screen and take-up shaft, a handle, preferably with endcaps, attached to the screen, and upper and lower guide rails possibly containing a unique latch mechanism. 
     The upper and lower guide rails may have ribs for guiding the screen as it is extended. The endcaps of the handle, which should be wider than the opening for the screen in the guide rails, ride along the ribs as the handle is pulled from the screen case. Since the endcaps are wider than the opening in the guide rails, the handle, and thus the screen, is positively retained within the rails as the screen is extended. 
     At the end of the guide rails, the ribs are removed. In this configuration when the handle reaches the end of the rails, the endcaps slip off the ribs. The endcap at the top of the handle then rests on a shelf within the upper guide rail. This simple procedure latches the screen in place. 
     The take-up shaft is attached to a gear assembly with a front access hole. A simple tool, such as a hexagonal wrench, can be inserted into the gear assembly to adjust the tension on the spring attached to the take-up shaft. This will change the force on the spring and effect the speed with which the screen is retracted into the screen case when it is unlatched. The gear assembly also includes a clutch mechanism that limits the maximum torque applied to the spring by the gear assembly. 
     In addition, the screen case is preferably molded to have the appearance of a typical door molding. A similar molding may be placed opposite the screen case to give the appearance of a normal door casing. The mantle can also be molded in a similar manner. The upper guide rail will be added to or incorporated into the mantle. 
     The lower guide rail is incorporated into a typical doorsill, which reduces the risk of tripping over the guide rail when entering or leaving through the door. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of a rolling screen according to a preferred embodiment of the invention; 
     FIG. 2 is an exploded view of the rolling screen; 
     FIG. 3 is an exploded fragmentary view of the upper portion of the pillar housing and rolling screen; 
     FIG. 4 is an exploded fragmentary view of the base of the pillar housing, rolling screen and gear assembly; 
     FIG. 5 is a side view of the upper rail; 
     FIG. 6 is a side view of the lower rail and novel latch mechanism; 
     FIG. 7 is a side view of the upper rail and handle; 
     FIG. 8 is a side view of the lower rail detail and doorsill; 
     FIG. 9 is a side view of the upper rail and novel latch mechanism; 
     FIG. 10 is a side view of the lower rail detail and doorsill; 
     FIG. 11 is an exploded view of the gear assembly; and 
     FIG. 12 is an exploded view of the worm and clutch assembly. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A retractable screen door constructed in accordance with a preferred embodiment of the invention is illustrated in the drawings and designated  10 . While the screen will be explained for use with a door, it is to be understood that the retractable screen may be used for any opening. In addition, while the screen will be explained in relation to exterior use, it is to be understood that the design is suitable for both interior and exterior use. 
     A screen  16  is pulled from a pillar housing  11  by handle  12  across an opening. The screen  16  is guided by upper and lower guide rails,  13  and  14  respectively, as it is pulled from pillar housing  11 . Lower rail  14  is incorporated into doorsill  15  and forms part of the door casing. 
     FIG. 2 shows the major components of the screen door  10 . The screen door  10  has four basic framing members. In the preferred embodiment the four framing members are connected to the doorjamb. It is required is that the framing members be in contact in the configuration specified. A pillar housing  11  is a hollow pillar designed to be vertically mounted on one side of a door opening. A solid pillar  17  is designed to be vertically mounted on the side of a door opening opposite the pillar housing  11 . A mantle  18  is a molding, including a guide rail  13  to be explained later, designed to be abutted to, and mounted horizontally above, the pillar housing  11  and solid pillar  17 . Lower rail  14  is designed to be mounted horizontally between the pillar housing  11  and the solid pillar  17 . The lower rail  14  is preferably mounted to doorsill  15 . The sill  15  is a typical doorsill. The design of the combined doorsill  15  and lower rail  14  will be discussed in further detail below. 
     The exemplified screen door  10  further includes a take-up shaft  21 . The screen  16  is made of a flexible material, attached to the take-up shaft  21  along one edge, and wound around the take-up shaft  21 . A handle  12  is attached to the screen  16  in such a way as to allow the screen  16  to be extended across a door opening by the handle  12 . The screen  16  is centered on the handle  12 . 
     FIG. 3 shows an exploded view of the upper portion of the screen door assembly, including a damper housing  27  which is attached to the top of the take-up shaft  21 , and a damper  28  is inserted into the damper housing  27 . The damper  28  and damper housing  27  can be any damper assembly known in the art, and can be attached at either end of the take-up shaft  21 . The take-up shaft  21 , screen  16 , coil spring  24 , and damper housing  27  should be concealed within the pillar housing  11 . The damper  28 , if present, or take-up shaft  21  is rotatably mounted to the pillar cap  29 . The pillar cap  29  can be attached to the structure where the screen door is mounted by use of fastener  20 . Fastener  20  can be any fastener capable of securing the pillar cap  29  to a structure, such as a wood screw. The pillar cap  29  can be attached to the pillar housing  11  by any reasonable fastening means, for example screws  22  (one of which is not shown). 
     The take-up shaft  21  is preferably located approximately in the center of the pillar housing  11 . When wound around the take-up shaft  21 , the screen  16  fits within the pillar housing  11 . The handle  12  is attached along the free edge of the screen  16 , as previously shown. The handle  12  preferably fits within a pillar slot  30  in the pillar housing  11 . The handle  12  protrudes from the pillar slot  30  sufficiently to allow a user to grasp the handle  12  when he wishes to extend the screen  16 . The screen  16  is positioned so that, as the handle  12  is pulled, the screen  16  is extended through pillar slot  30 . 
     FIG. 4 shows a coil spring  24  wound around a spring subassembly  25 , which is attached to the take-up shaft  21  near the base of the take-up shaft  21 . The coil spring  24  and spring subassembly  25  can be attached at either end of the take-up shaft  21 , but should be attached at the end of the take-up shaft  21  opposite the damper  28 , if present. The spring subassembly  25  is also attached to the gear assembly  26 , which is used to adjust the tension on the coil spring  24 . A protrusion at the base of the spring subassembly  25  is designed to fit within a slot in the gear assembly  26 . The gear subassembly  26  is attached to the pillar housing  11  using any reasonable fastening means, such as screws  22 . A fastener  20  can also be used to attach the gear assembly  26  to the structure the screen door  10  is mounted on. 
     The screen  16  is extended past a door opening by pulling handle  12 . As handle  12  is pulled, the screen  16  moves though upper rail  13  and lower rail  14 . The screen  16  can be maintained in the extended position by use of a latch mechanism. This can be by a conventional latch mechanism, many of which are known in the art, or by the novel latch mechanism discussed further in this application. When the screen  16  is latched, it preferably covers the entire door opening. 
     The upper rail  13 , which can be seen in FIG. 5, has a screen opening  35  through which the screen  16  advances. A guide ledge  36  is located above the screen opening  35 . Optionally ribs  37  are located on the guide ledge  36  and run the length of the upper rail  13 . While the ribs  37  can run the entire length of the upper rail  13 , in an exemplified embodiment the ribs  37  stop before the end of the upper rail  13  that is abutted to the solid pillar  17 . This latter configuration of the ribs  37  forms part of the unique latch mechanism to be discussed further in this application. Additionally, brushes  38  can be inserted into brush slots  39  in the upper rail  13 . The brushes  38  keep insects and debris from entering the upper rail  13 . 
     FIG. 6 shows the lower rail  14  and doorsill  15 , the lower rail  14  being incorporated into the doorsill  15 . The doorsill  15  is designed to function like a typical doorsill. The doorsill  15  is usually a wedge shape, which is designed to slope down from the doorway, having an upper end  40  and a lower end  41 . The lower rail  14  is designed to have a low profile so it will align with the lower end  41  of the doorsill  15 , the lower end  41  being the end farthest from the doorway. The lower rail  14  is preferably attached to the doorsill  15  at the lower end  41 . Since the lower rail  14  aligns with the lower end  41 , the possibility of tripping over the lower rail  14  is minimized. 
     The lower rail  14  has a screen opening  35  through which the screen  16  advances. The lower rail includes ribs  37  along the bottom  42 . These ribs  37  run most of the length of the lower rail  14 , but the ribs  37  stop near the end of the lower rail  14  abutted to the solid pillar  17 . This latter configuration of the ribs  37  forms part of the unique latch mechanism to be discussed further in this application. Additionally, brushes  38  are included in brush slots  39  in the lower rail  14 . These brushes  38  perform similar functions to the brushes  38  in the upper rail  13 . Additionally, the lower rail  14  can include weep holes  52 . The weep holes  52  allow water to drain from the screen door  10 , for instance after a rainstorm. The weep holes  52  are preferably are slot shaped and are placed very low on the side of the lower rail  14  to allow the maximum amount of water to drain through the weep holes  52 . 
     FIG.  7  and FIG. 8 show the screen  16  as it is being advanced through the upper rail  13  and lower rail  14 . The handle  12  preferably has a top cap  45  and bottom cap  46 . The top cap  45  and bottom cap  46  are preferably larger than the screen openings  35  in the upper rail  13  and lower rail  14 . If the top cap  45  and bottom cap  46  are larger than the screen openings  35 , it will not be possible to accidentally remove the screen handle  12  during use, since the top cap  45  and bottom cap  46  are attached to the screen handle  12  and can not be removed from the upper rail  13  or lower rail  14 . The top cap  45  and bottom cap  46  glide along ribs  37  in the upper rail  13  and lower rail  14 , if ribs  37  are present. 
     FIG.  9  and FIG. 10 show the latch mechanism referred to earlier. In the preferred embodiment of the latch mechanism ribs  37  are present in both the upper rail  13  and lower rail  14 . The ribs  37  in the upper rail  13  run from the housing end  50  almost to the pillar end  51 . The ribs  37  end before reaching the pillar end  51 , leaving enough space for the top cap  45  to slip off the ribs  37  and rest on the guide ledge  36 . The ribs  37  in the lower rail  14  similarly run from the housing end  50  almost to the pillar end  51 . The ribs should end prior to the pillar end  51 , leaving enough space for the bottom cap  46  to slip off the ribs  37 . 
     In an exemplified embodiment, the height of the ribs  37  in the upper rail is ⅛″ and the height of the ribs  37  in the lower rail is ¼″. In this configuration the top cap  45  will rest on the guide ledge  36  and the bottom cap  46  will hang suspended within the lower rail  14 . It is possible to have the heights of the ribs  37  be equal in the upper rail  13  and lower rail  14 , which would allow the bottom cap  46  to rest on the bottom  42  of lower rail  14  and the top cap  45  to rest on the guide ledge  36 . 
     As can be seen from FIG.  9  and FIG. 10 the top cap  45  and bottom cap  46 , after slipping from the ribs  37 , will be blocked from retracting by the ribs  37 . This will keep the screen  16  in an extended position when in the latched position. When the user wishes to retract the screen  16 , the handle is lifted so the ribs  37  no longer block the top cap  45  and bottom cap  46 . If the handle  12  is released in this position, the coil spring  24  will retract the screen  16 . 
     FIG. 11 shows the gear assembly  60 , which includes a gear subassembly  61 , worm  62 , and worm gear  63 . The worm  62  has teeth  64  that lock with the teeth  65  of the worm gear  63 . There is also a cap  69  for keeping the worm  62  and worm gear  63  in contact, which can be attached to the gear subassembly  61 . The worm gear  63  also has a spring slot  66  for insertion of the spring subassembly  25 . As the pictured worm  62  is rotated in one direction, the teeth  65  of the worm gear  63  are advanced. The worm gear  63  then rotates, causing the spring subassembly  25  to rotate, and increasing the degree to which the coil spring  24  is compressed. The greater the compression of the coil spring  24 , the greater the speed and force with which the screen  16  will be retracted. Similarly, if the worm  62  is rotated in the opposite direction, the rotary gear  63  rotates in such a manner as to reduce the compression of the coil spring  24 . 
     The gear subassembly  61  has an access hole  67  on one side. This access hole  67  is accessible to a user after construction of the screen door  10 . The head  68  of the worm  62  should be designed to be rotated by an appropriate tool, thus allowing a user to adjust the tension on the coil spring  24 . The access hole  67  should be large enough to allow insertion of a tool to rotate the worm gear  62 . This will allow the user to determine the tension of the coil spring  24 , and thus the speed of retraction of the screen  16 . The location of the gear assembly  60  on the screen door  10  should allow easy access to the access hole  67 . 
     FIG. 12 shows a preferred embodiment of the worm  62 , including a gear member  70  and adjustment member  71 . A tool aperture  72  is formed in the head of the adjustment member  71 , into which a tool can be inserted through access hole  67  to rotate adjustment member  71 . The adjustment member  71  includes adjustment teeth  73 . Gear teeth  74  on the gear member  70  are designed to lock with the adjustment teeth  73  so as to allow rotation of the gear member  70  and adjustment member  71  together when a tool is inserted into the tool aperture  72 . When the adjustment member  71  is rotated in one direction the frictional force between the adjustment member  71  and the gear member  70  causes the gear member  70  to rotate in the same direction. This rotation compresses the coil spring  24  as explained above. 
     A ramped engagement between gear member  70  and adjustment member  71  limits the maximum torque that can be transmitted from adjustment member  71  to gear member  70 . The maximum spring compression is defined by the frictional force between the gear member  70  and adjustment member  71 . After the coil spring  24  has been compressed a certain amount, the force required to compress the coil spring  24  will be greater than the frictional force between the adjustment member  71  and the gear member  70 . At this point the adjustment member  71  slides along the gear member  70 , the gear member  70  will not be rotated, and thus the coil spring  24  will not be further compressed. This maximum spring compression will vary depending on the spring used, and the shape of the interlocking adjustment teeth  73  and gear teeth  74 . This feature increases the safety of the screen door  10  because the retraction force and speed is limited by the maximum spring compression. 
     In addition, due to the configuration of the preferred worm  62 , no matter how tight the coil spring  24  is compressed, it can always be loosened. When rotated in the opposite direction, the front face  75  of each adjustment tooth  73  pushes against the back face  76  of a gear tooth  74 , thus locking together the gear member  70  and adjustment member  71 . Since the force required to unlock the teeth when rotated in the opposite direction is greater than the frictional force used to compress the coil spring  24 , even if the coil spring  24  is at the maximum spring compression, the compression of the coil spring  24  should be easily reduced. 
     In an alternative embodiment, there are two pillar housings  11  and no solid pillar  17 . One pillar housing  11  is located on each side of a door opening. Each pillar slot  30  should face the door opening. In this configuration, when a handle  12  is pulled from the corresponding pillar slot  30  it will extend the screen  16  across the door opening. Each pillar housing  11  is abutted to an upper rail  13  and a lower rail  14 . These will be located in the same positions as in the previous embodiments. When the screens  16  are fully extended the handles  12  will butt against each other and form a seal. The handles  12  can latch together using a traditional latch mechanism, or can latch using the novel latch mechanism previously disclosed. If the novel latch mechanism is used, each pillar housing  11  can have corresponding upper and lower rails,  13  and  14  respectively, with the ribs  37  removed at the end where the rails come in contact. Alternatively there can be one upper rail  13  and one lower rail  14  with ribs  37  removed in the middle. This configuration is useful when installing the retractable screen in front of double doors, such as French doors. 
     Preferably the framing members are designed to appear to be a symmetrical door casing. The pillar housing  11  and solid pillar  17  have the same outward appearance, and this appearance is that of door molding. The pillar housing  11  has an interior opening to house the screen assembly previously discussed. Additionally, the mantle  18  is molded into the shape of a normal door mantle. These members preferably have the shape shown or the shape of copending design application for DOOR MOLDING filed the same day as this application with inventors David A. DeBlock, Michael J. Kowalczyk and Michael S. Eveland. The lower rail  14  will blend with the door casing if attached to the doorsill  15  in the manner previously described. 
     There are many methods known in the art for producing the desired shape for the pillar housing  11 . For example, the pillar housing  11  could be either an aluminum or plastic extrusion. Any method suitable for producing the pillar housing  11  could also be used to produce upper rail  13  and lower rail  14 . Many methods are known in the art for producing the solid pillar  17  and mantle  18  as well. For example, the solid pillar  17  and mantle  18  could be plastic extrusions or milled from wood. 
     The above descriptions are those of preferred embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the Doctrine of Equivalents.

Technology Classification (CPC): 8