Abstract:
An automatically-closing screen door is provided that is typically for enclosure with a conventional sliding glass door used for patio entry in residential and/or commercial dwellings. The automatically-closing screen door preferably has a counterweight that is employed to provide a controllable closing force to the door.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application Serial No. 60/319,397, filed Jul. 15, 2002, and U.S. Provisional Application Serial No. 60/319,752, filed Dec. 4, 2002, both entitled “Automatically-Closing Screen Door and Closing Speed Adjuster for the Same.” 
     
    
     
       BACKGROUND OF INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The invention relates to an automatically-closing screen door, typically for enclosure with a conventional sliding glass door used for patio entry in residential and/or commercial dwellings. More particularly, the invention relates to an automatically-closing screen door in which a counterweight is employed to provide a controllable closing force to the door.  
           [0004]    2. Description of the Related Art  
           [0005]    Sliding glass door assemblies have become commonplace in both residential and commercial dwellings. A sliding door is mounted on a horizontal track in offset alignment with a fixed door. When an occupant of a dwelling desires to enter or leave the dwelling, the occupant slides the sliding door along the track to open and close the sliding door with respect to the fixed door.  
           [0006]    In addition to having a sliding glass door, many sliding glass door assemblies have a sliding screen door as well mounted for sliding movement on a track that is generally parallel to the horizontal track for the sliding glass door. The sliding screen door allows the sliding glass door to be left in an opened position to allow airflow into the dwelling while preventing insects and other undesirable entities from entering the dwelling.  
           [0007]    Sliding screen doors are typically moved between opened and closed positions by an occupant grasping a handle on the screen door and manually sliding the sliding screen door between the opened and closed positions. This is acceptable if the sliding screen door is maintained in the closed position.  
           [0008]    However, if the sliding screen door is left in an open position, the sliding screen door does not return to the closed position on its own accord. This can be a problem if the occupant has young children who frequently forget to close the sliding screen door after entering or leaving the dwelling. In addition, if the occupant is entering or leaving the dwelling carrying an object or performing an activity that requires both of the occupant&#39;s hands (e.g., carrying trays of food), it may also be difficult to manually close the sliding screen door in an acceptable amount of time.  
           [0009]    One solution to these problems has been to add a spring (e.g., a coil spring or a bungee cord) which is attached at one end to the sliding screen door and at an opposite end to a frame surrounding the sliding screen door. The spring thereby biases the sliding screen door to the closed position.  
           [0010]    These spring-based automatic closure systems have some problems. First, the resistance on the screen door increases as you open the door since the return force of a spring-based system is proportional to the length it is extended (see Hooke&#39;s law where the spring force F=kx). Second, when a spring-based automatic closure system is released so that it travels from the opened position to the closed position, it can close very quickly as a result of the conversion of the potential energy stored in the extended spring into the kinetic energy as the sliding screen door moves toward the closed position. Third, repair of these so-called spring-based automatic closure systems can be difficult and costly. Fourth, the spring used in the so-called spring-based automatic closure system can lose elasticity over time and require replacement.  
         SUMMARY OF INVENTION  
         [0011]    In one aspect, the invention relates to an automatically-closing screen door, typically for enclosure with a conventional sliding glass door used for patio entry in residential and/or commercial dwellings. More particularly, the invention relates to an automatically-closing screen door in which a counterweight is employed to provide a controllable closing force to the door. In one embodiment, the sliding screen door described herein according to the invention includes an adjuster which allows an occupant to adjust a closing velocity of the door.  
           [0012]    Invention overcomes the limitations of the prior art by offering a simple manufacture, assembly and operation. It has a low profile relative to the doorjamb, has a low cost to manufacture and has little resistance when opening the sliding screen door.  
           [0013]    One aspect, the invention relates to a door slidable between a door open position permitting travel therethrough and a door closed position obstructing travel therethrough comprising a door frame defining a central opening therein through which ingress and egress can occur; and an automatic closure system comprising: a cable with a first end and a second end, wherein the first end is mounted to an upper portion of the sliding door; a counterweight connected at the second end of the cable and movable between a counterweight open position when the sliding door is in the door open position and a counterweight closed position when the sliding door is in the door closed position, wherein the counterweight open position is above the counterweight closed position; and a pulley mounted to the door frame for redirecting the cable from a generally horizontal orientation near the first end to a generally vertical orientation near the second end; wherein when a force is applied to the sliding door to cause the sliding door to slide to the door open position, the counterweight is elevated from the counterweight closed position to the counterweight open position by virtue of the attachment of the cable to the sliding door via the pulley, and when the force is released, the counterweight descends to the counterweight closed position thereby returning the sliding door to the door closed position.  
           [0014]    Another aspect, the invention relates to a kit for adapting a sliding door mounted within a door frame to automatically move between a door open position permitting travel therethrough and a door closed position obstructing travel therethrough, the kit comprising: a cable with a first end and a second end, wherein the first end is adapted to be mounted to the sliding door; a counterweight adapted to be connected at the second end of the cable and movable between a counterweight open position when the sliding door is in the door open position and a counterweight closed position when the sliding door is in the door closed position; and a pulley adapted to be mounted to the door frame for redirecting the cable from a generally horizontal orientation near the first end to a generally vertical orientation near the second end; wherein, when the pulley is mounted to the door frame and when the first end of the cable is mounted to the sliding door, passed through the pulley and has its second end mounted to the counterweight, the sliding door will automatically move between the door open position and the door closed position after a force is applied to the sliding door to cause the sliding door to move to the door open position whereby when the force is released, the counterweight descends to the counterweight closed position thereby moving the sliding door to the door closed position.  
           [0015]    Embodiments of the invention are also contemplated. The automatic closure system further can comprise a bracket mounted to the upper portion of the sliding door, wherein the cable is mounted to the bracket. The sliding door can be a screen door. The cable can be made from nylon. The pulley can be a wheel-type pulley. The pulley can be a complex pulley system.  
           [0016]    The door frame can comprise a doorjamb and the automatic closure system can further comprise a cover mounted on the doorjamb to visually conceal the pulley, the second end of the cable, and the counterweight. The counterweight can have a thin profile so that the counterweight can easily be concealed under the cover. The counterweight can be at least one of a lead plate, a lead rod, a lead member, a lead-filled tube and a stainless steel member. The cover can have an opening to permit the cable to pass through the cover. The cover can have an elongated shape so that the cover can have an appearance similar to and blends in with the doorjamb.  
           [0017]    The automatic closure system can further comprise an adjuster to control movement of the counterweight between the counterweight open and counterweight closed positions. The adjuster can comprise a housing and a U-shaped member fastened to the housing, wherein the cable is received within the U-shaped member. The U-shaped member can be selectively moved toward the housing to constrict the cable between the U-shaped member and the housing, thereby restricting movement of the cable through the adjuster, retarding movement of the counterweight, and causing the sliding door to slide more slowly to the door closed position. The U-shaped member can be selectively moved away from the housing to loosen the cable, thereby causing the sliding door to slide at a faster rate to the door closed position. The adjuster can further comprise thumb screws to move the U-shaped member relative to the housing.  
           [0018]    The door frame can comprise a doorjamb, the automatic closure system can further comprise a cover mounted on the doorjamb to visually conceal the pulley, the second end of the cable, and the counterweight, and the adjuster is mounted to one of the doorjamb and the cover. The door frame can comprises a doorjamb; the automatic closure system further comprises a cover mounted on the doorjamb to visually conceal the pulley, the second end of the cable, the counterweight, and the adjuster; and wherein the adjuster comprises an arm having a first end mounted to the cover and a second end that extends towards the doorjamb and abuts the counterweight as it moves between the counterweight open and counterweight closed positions, wherein the second end of the arm imparts a damping force onto the counterweight as it moves between the counterweight open and counterweight closed positions, thereby causing the sliding door to move more slowly between the door open position and the door closed position.  
           [0019]    The adjuster can further comprise a bias adjuster to control the damping force imparted onto the counterweight by the arm. The bias adjuster can comprise a threaded fastener that is mounted through the cover and contacts the arm between the first and second ends of the arm so that movement of the threaded fastener towards the arm increases the amount of damping force exerted by the arm and movement of the threaded fastener away from the arm decreases the amount of damping force exerted by the arm. The arm can be comprised of a resilient material.  
           [0020]    The adjuster can further comprise a spring mounted between the cover and the second end of the arm, wherein the spring biases the arm towards the counterweight. The automatic closure system can further comprise a cable brake to stop movement of the cable to retain the sliding door in the door open position or in the door closed position. The cover can have an opening to permit the cable to pass through the cover, and the cable brake can comprise a flange mounted to the cover near the opening and a tab slidably mounted to the flange, wherein the tab is movable between a released position where the tab does not obstruct the cable from moving through the opening and an engaged position where the tab blocks the opening to prevent the cable from moving through the opening and thereby retain the sliding door in the door open position or in the door closed position.  
           [0021]    The damper can be provided, wherein the damper can selectively apply a drag force on at least one of the pulley, the cable, and the counterweight to control the travel of the sliding door during movement of the sliding door from the door open position to the door closed position. The damper can apply a compression force to the cable to control the movement of the sliding door. The damper can include a U-shaped member which surrounds the cable and pinches the cable between at least one of the damper, the cover, and the door frame. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0022]    [0022]FIG. 1 is a fragmentary, perspective view of a conventional sliding glass door in a closed position, wherein the sliding glass door includes an automatically-closing screen door according to the invention.  
         [0023]    [0023]FIG. 2 is a front elevational view of a first embodiment of the automatically-closing screen door of FIG. 1 in a closed position.  
         [0024]    [0024]FIG. 3 is a front elevational view of the first embodiment of the automatically-closing screen door of FIG. 1 in an open position.  
         [0025]    [0025]FIG. 4 is a side elevational view of a door jamb portion of the sliding glass door of FIG. 1 showing a portion of the first embodiment of the automatically-closing screen door of FIG. 1.  
         [0026]    [0026]FIG. 5 is a side elevational view of a closing force adjuster for use with the automatically-closing screen door of FIG. 1.  
         [0027]    [0027]FIG. 6 is a top plan view of the closing force adjuster of FIG. 5 for use with the automatically-closing screen door of FIG. 1.  
         [0028]    [0028]FIG. 7 is a top plan view of the closing force adjuster of FIG. 5 shown compressing a return cable, thus applying an additional drag to the closure of the screen door.  
         [0029]    [0029]FIG. 8 is a front elevational view of a second embodiment of the automatically-closing screen door of FIG. 1 in a closed position.  
         [0030]    [0030]FIG. 9 is a front elevational view of the second embodiment of the automatically-closing screen door of FIG. 1 in an open position.  
         [0031]    [0031]FIG. 10 is a cross-sectional view from a front elevational orientation in which a cover for the automatically-closing door of either the first or second embodiments is shown having a cable brake movably mounted thereto, wherein the cable brake is shown in a released position with respect to a cable therefor.  
         [0032]    [0032]FIG. 11 is a cross-sectional view in an orientation similar to that of FIG. 10 in which the cable brake is shown in an engaged position thereby restricting movement of the cable with respect to the cover for the automatically-closing screen door of either the first or second embodiments. 
     
    
     DETAILED DESCRIPTION  
       [0033]    Referring now to the drawings and to FIGS.  1 - 3  in particular, a sliding door assembly  10  (often referred to by those skilled in the art as a “patio” door) is shown comprising a fixed door  12 , a sliding glass door  14  and a sliding screen door  16  mounted within a door frame  18 . It will be understood that the sliding glass door  14  and the sliding screen door  16  are mounted for slidable movement with respect to the door frame  18  in any suitable fashion which will be apparent to one skilled in the art so that further description of the particulars of the slidable mounting of the doors  14  and  16  is not necessary.  
         [0034]    With particular reference to FIGS. 2 and 3, the screen door  16  is shown in greater detail in a closed position and an open position, respectively. The screen door  16  is a conventional door comprising a generally rectangular frame  20  with a taut mesh screen  22  therebetween.  
         [0035]    In accordance with the invention, a first embodiment of an automatic closure system  24  is mounted between the sliding glass door frame  18  and the screen door  16 . The automatic closure system  24  comprises a bracket  26 , a cable  28 , a pulley  30 , a counterweight  32  and a cover  34 .  
         [0036]    The bracket  26  is preferably mounted to an upper portion of the screen door  16 . The pulley  30  is preferably mounted to the cover  34  in generally horizontal planar alignment with the bracket  26 . A first end  36  of the cable  28  is mounted to the bracket  26  at the upper portion of the screen door  16 . A second end  38  of the cable  28  is mounted to the counterweight  32 . As can be seen in FIGS. 2 and 3, the cable  28  is fed over the pulley  30  so that the counterweight is hung generally vertically by the second end  38  of the cable  28  and the first end  36  of the cable imparts a closure force on the screen door  16 . The cover  34  is mounted over the pulley  30 , the second end  38  of the cable  28 , and the counterweight  32 . Preferably, the cover  34  has an opening  40  at an upper end thereof for uninterrupted passage of the cable  28  as the door moves between the open and closed positions.  
         [0037]    The bracket  26  can be any suitable bracket or fastener for connecting the first end  36  of the cable  28  to the screen door.  
         [0038]    The cable  28  can be made of any suitable material including, but not limited to, nylon.  
         [0039]    The pulley  30  can be any conventional wheel-type pulley or other suitable member, such as an eyelet, looped fastener, sleeve, etc. which performs the function of redirecting the cable  28  from a generally horizontal orientation at the first end  26  to a generally vertical orientation at the second end  38  thereof.  
         [0040]    The counterweight  32  is any suitable weight, although it has been found that an elongated, thin weight member (e.g., a thin lead plate or rod) works best because it has a thin profile and can be mounted within the cover  34  without interrupting the visual aesthetics or functional operation of any components of the door assembly  10 .  
         [0041]    The cover  34  is preferably a low-profile sheath that conceals the interior components of the automatic closure system  24 . The cover  34  is also preferably elongated a sufficient extent to conceal the interior components of the automatic closure system  24  regardless of the length of travel of the counterweight  32  (e.g., at least three feet for a 36-inch screen door  16  plus the length of the counterweight  32 ). It will also be understood that complex pulley arrangements can be substituted for the pulley  30  without departing from the scope of this invention. For example, a complex pulley system (such as that found in compound bows) can be substituted for the pulley  30  whereby a shorter cover  34  can be employed because the length of travel of the cable  28  would be reduced as a result of the complex pulley arrangement.  
         [0042]    The mounting of the cover  34  is also shown in FIG. 4 on a portion of the door frame  18  comprising a sliding glass doorjamb  18   a , a fixed glass doorjamb  18   b , a screen doorjamb  18   c  and an exterior doorjamb portion  18   d . As can be seen, while any location on the door frame  18  would be appropriate, it is preferred that the cover  34  (and the associated automatic door closure system  24 ) be located on the fixed glass doorjamb  18   b  since the offset nature of the fixed glass door  12  with respect to the slidable glass door  14  provides a degree of clearance into which the automatic door closure system  24  can be mounted.  
         [0043]    The use of the automatic closure system  24  associated with the screen door  16  is simple. When the screen door  16  is in the closed position (see FIG. 2), an occupant may grasp a suitable handle portion (not shown) on the screen door and laterally slide the screen door  16  with respect to the door frame  18  to the open position as shown in FIG. 3. The occupant moves the screen door  16  to the open position as shown in FIG. 3 against the counterweight  32  which is moved to a raised position as shown in the drawings. When the occupant has entered or exited through the door frame  18  as desired (i.e., by passing through the void left by the opened screen door  16 ), the occupant need merely release the occupant&#39;s grasp on the screen door  16  at which time the counterweight falls by gravity to a lowered position, returning the screen door  16  to the closed position as shown in FIG. 2.  
         [0044]    It will be understood that the particular poundage making up the counterweight  32  can be selected to return the screen door  16  from the open position to the closed position at a predetermined rate. In addition, the counterweight  32  can be preselected or optionally adjusted with additional or fewer weights depending upon the friction imparted by the screen door  16  on its associated track during slidable movement of the screen door  16  relative to the door frame  18 . That is, the smoother or rougher the movement of the screen door  16  relative to its associated track, the less or more weight may be required for the counterweight  32  to close the door in a desirable rate and fashion.  
         [0045]    In addition to varying the weight of the counterweight  32 , the invention also contemplates the provision of an adjuster  42  which varies the drag encountered by the cable  28  as the screen door  16  moves between the opened and closed positions. The adjuster  42  is shown in FIGS. 2 and 3 and in greater detail in FIGS.  5 - 7 .  
         [0046]    The adjuster  42  comprises a U-shaped member  44  which is fastened to a housing  46  which, in turn, is mounted to the door frame  18  or the cover  34 . The U-shaped member  44  can be selectively moved toward or away from the housing  46 . In assembly, the cable  28  is passed through the arms of the U-shaped member  44  so that the cable  28  is selectively intertwined with the U-shaped member  44 . As the U-shaped member  44  is tightened onto the housing  46  (such as by thumb screws  48  shown in FIG. 5), the cable  28  is trapped between the housing  46  and an interior surface of the U-shaped member  44 . The varying force of the adjuster  42  is shown by the various positions of the U-shaped member  44  with respect to the housing  46  in FIGS. 6 and 7.  
         [0047]    As the U-shaped member  44  is further tightened against the housing  46 , the U-shaped member  44  restricts the movement of the cable  28  therethrough, causing the screen door  16  to close more slowly (see FIG. 7). Conversely, as the U-shaped member  44  is positioned away from the housing  46  (such as by loosening the thumb screws  48  as shown in FIG. 6), the U-shaped member does not contact the cable  28 , causing the screen door  16  to close with the weight of the counterweight  32  and thus close more quickly than if the adjuster  42  was applying drag to the cable  28  as described.  
         [0048]    Of course, the U-shaped member  44  can also be positioned sufficiently far from the housing  46  so that the U-shaped member  44  and the housing  46  do not contact the cable  28  whatsoever, thus providing no additional drag to the cable  28 .  
         [0049]    Also in accordance with the invention, a second embodiment of an automatic closure system  24  is shown in FIGS.  8 - 9  in which elements of the second embodiment of FIGS.  8 - 9  which have a corresponding structure and/or function in FIGS.  1 - 7  are referred to by like reference numerals.  
         [0050]    The second embodiment of the automatic closure system  24  also includes a counterweight  32  located within a suitable cover  34 , however, in this embodiment, the adjuster  42  for controlling the closing speed of the screen door  16  comprises an arm  60  having a first end  62  mounted to an interior portion of the cover  34  and a second end  64  extending inwardly therefrom in register with an axial path of travel of the counterweight  32  between the open and closed positions of the door.  
         [0051]    Preferably, the arm  60  is mounted so that the second end  64  thereof is positioned to abut the counterweight  32  as it moves toward the closed position of the screen door  16 . The second end  64  of the arm  60  can be biased into the counterweight travel path by a spring  66 , preferably mounted between the second end  64  of the arm  60  and the cover  34 . Preferably, the arm  60  is mounted to the cover  34  at a desirable vertical height so that the counterweight  32  contacts the arm  60  during its travel as the screen door  16  moves between the open and closed positions.  
         [0052]    It will be understood that the spring  66  is optional, and that the arm  60  can also be made from a material which has an inherent resiliency so that some resistance/damping is imparted to the counterweight  32  by the arm  60  when the screen door, and thus the counterweight  32 , moves between the open and closed positions.  
         [0053]    A bias adjuster  68  is provided with the arm  60  for adjusting the amount of bias, and thus the amount of damping force, applied against the movement of the counterweight  32  between the open and closed positions. An example of the bias adjuster  68  is shown in FIGS.  8 - 9  as a threaded fastener passed through the cover  34  and contacting the arm  60  between the first and second ends  62  and  64  thereof. Thus, it can be seen that inward and outward axial movement of the bias adjuster  68  relative to the arm  60  can increase and decrease, respectively, the amount of force required by the counterweight  32  to deflect the arm  60  during movement of the screen door  16  between the open and closed positions.  
         [0054]    The use of the second embodiment of the automatic closure system  24  for a screen door  16  will now be described. Initially, the door is typically in a closed position as shown in FIG. 8. A user will open the door by slidably moving the screen door  16  (in a rightward direction in the orientation shown in FIGS.  8 - 9 ), thus causing the cable  28  to lift the counterweight  32  via the pulley  30 . The screen door  16 , once opened, is in the position as shown in FIG. 9. Once the user has egressed through the door opening, the user can release the screen door  16  which causes gravity to act on the counterweight  32 , pulling the screen door  16  back toward the closed position as shown in FIG. 8.  
         [0055]    During the travel of the screen door  16  from the open position (FIG. 9) to the closed position (FIG. 8), the counterweight  32  encounters the arm  60 , typically some portion of the arm  60  between the first and second ends  62  and  64  thereof, depending upon the position of the bias adjuster  68 . The counterweight  32  bears against the arm  60 , and thus against the bias of the optional spring  66 , which causes the second end  64  of the arm  60  to deflect toward the cover  34 . The action of the arm  60  against the movement of the counterweight  32  slows the movement of the counterweight  32 , and thus slows the closure movement of the screen door  16  to a desirable speed, which can be set by the user by position of the bias adjuster  68 .  
         [0056]    In the example shown in FIGS.  8 - 9 , the closure speed of the screen door can be easily set by threadably rotating the fastener making up the bias adjuster  68 . This threadable rotation of the bias adjuster  68  increases or decreases (depending upon the direction of rotation of the bias adjuster  68 ) the force applied by the arm  60  on the counterweight  32 .  
         [0057]    Another feature of the automatic closure system  24  according to the invention is shown in FIGS.  10 - 11  in the form of a cable brake  50 . The function of the cable brake  50  is to halt movement of the cable  28 , preferably when the screen door  16  is in the open position. Thus, the counterweight  32  cannot draw the screen door  16  closed, allowing a user to essentially prop the screen door in the open position, such as during times when a large amount of item(s) need to be transported into and out of the screen door opening.  
         [0058]    The cable brake  50  can be used with either of the first embodiment of FIGS.  1 - 7  or the second embodiment of FIGS.  8 - 9 . As shown in FIGS.  10 - 11 , the cable brake  50  comprises a tab  52  slidably mounted via a flange  54  to the cover  34 . The tab  52  of the cable brake  50  is preferably movable between a released position as shown in FIG. 10 and an engaged position as shown in FIG. 11. In the released position, the tab  52  does not obstruct the cable  28  from passing through the opening  40  in the cover  34 . In the engaged position, the tab  52  is slid upwardly so that the cable  28  is prevented from further travel through the opening  40 , preferably by blocking the opening  40 .  
         [0059]    The tab  52  can be maintained in the engaged position of FIG. 11 by engagement of detents (not shown) on the tab  52  within recesses on the cover  34 , although, as shown in FIG. 11, the tab  52  can simply create a friction lock of the cable  28  between the tab  52  and the cover  34  so that the cable  28  does not move into the opening  40  of the cover  34 .  
         [0060]    In use, if a user desires to prevent the automatic closure system  24  from operating, i.e., to prevent the counterweight  32  from drawing the screen door  16  from the open position to the closed position via the cable  28 , the tab  52  is slid from the released position (FIG. 10) to the engaged position (FIG. 11) in which the cable  28  is prevented from traveling into the opening  40  of the cover  34 . Thus, the screen door  16  stays in the open position. Once the user desires to close the screen door  16 , the tab  52  is returned to the released position, thus loosening the grip on the cable  28  and permitting the counterweight  32  to continue drawing the screen door  16  to the closed position via the cable  28 .  
         [0061]    The invention overcomes the limitations of the prior art by offering simple manufacture, assembly and operation. It has a low profile relative to the door frame  18 , has a low cost to manufacture and has little resistance when opening the sliding screen door unless the adjuster  42  or  68  and/or cable brake  50  is employed to provide additional resistance.  
         [0062]    While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.