Abstract:
This inventive concept discloses a door assembly comprising a custom-built doorframe housing a main door, which main door rotates within the doorframe by a major pivotal means. A spring-loaded leaf door is attached, by a minor pivotal means, within a cutout excised from the leading edge of the main door. As the main door rotates about its pivotal axis, the door is restrained from closing with full force upon human fingers or any other object that may be proximate the door jamb, or inner doorframe area. 
     The pivoting, or trailing, edge of the main door is abutted against elastomeric material affixed to the inner rear surface of the doorframe, thereby serving to prevent the insertion of fingers into what otherwise would be a hazardous gap. The optimal embodiment of this inventive concept features a doorframe having upper and lower ball bearing assemblies for containment and stable support of the main door pivotal means.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]      
         [0000]    
       
         
               
             
               
               
               
               
             
               
             
               
               
               
               
             
               
             
               
               
               
               
             
           
               
                   
               
             
             
               
                 U.S. Patent Documents 
               
             
          
           
               
                   
                 2,184,259 
                 Dec. 19, 1939 
                 Seaman 
               
               
                   
                 3,086,383 
                 Apr. 23, 1963 
                 Scott 
               
               
                   
                 3,141,204 
                 Jul. 21, 1964 
                 Wheeler 
               
               
                   
                 3,827,183 
                 Aug. 6, 1974 
                 Zimmerman, et al. 
               
               
                   
                 3,934,371 
                 Jan. 27, 1976 
                 Ulatowski, et al. 
               
               
                   
                 4,261,140 
                 Apr. 14, 1981 
                 McLean 
               
               
                   
                 4,290,233 
                 Sep. 22, 1981 
                 Hubbard 
               
               
                   
                 4,999,949 
                 Mar. 19, 1991 
                 Granlund 
               
               
                   
                 5,076,017 
                 Dec. 31, 1991 
                 Jacobs 
               
               
                   
                 5,092,077 
                 Mar. 3, 1992 
                 Teinturier-Milgram 
               
               
                   
                 5,765,311 
                 Jun. 16, 1998 
                 Kapler 
               
               
                   
                 6,141,909 
                 Nov. 17, 2000 
                 Hanson 
               
               
                   
                 6,311,432 
                 Nov. 6, 2001 
                 Watson 
               
               
                   
                 6,185,871 
                 Feb. 13, 2001 
                 Wang 
               
               
                   
                 6,434,888 
                 Aug. 20, 2002 
                 Shaw, et al. 
               
               
                   
                 6,832,450 
                 Dec. 21, 2004 
                 Shaharbani 
               
               
                   
                 7,047,694 
                 May 23, 2006 
                 Salzman 
               
               
                   
                 7,234,202 
                 Jun. 26, 2007 
                 Li 
               
               
                   
                 7,293,328 
                 Nov. 13, 2007 
                 Endres 
               
             
          
           
               
                 U.S. Patent Application Publications 
               
             
          
           
               
                   
                 2002/0046501 
                 Apr. 25, 2002 
                 Webb 
               
               
                   
                 2002/0157319 
                 Oct. 31, 2002 
                 Haq 
               
               
                   
                 2005/0108946 
                 May 26, 2005 
                 Shaharbani 
               
               
                   
                 2005/0183342 
                 Aug. 25, 2005 
                 Holden 
               
             
          
           
               
                 Foreign Patent Documents 
               
             
          
           
               
                   
                 WO 03/093622 
                 Nov. 13, 2003 (pub date) 
                 Garvey 
               
               
                   
                 JP 10072972 
                 Mar. 17, 1998 (pub date) 
                 Kogyo 
               
               
                   
                   
               
             
          
         
       
     
       OTHER REFERENCES 
       [0000]    
       
           Pediatrics, Vol.  27, No. 5, May, 1961, pg 842 
         www.fingershield.co.uk 
         The Martin Finger Shield™ Garage Door System 
         www.fingerkeeper.co.uk 
       
     
       PRIORITY CLAIM 
       [0006]    This application claims the benefit of provisional patent application No. 61/008,027, filed on Dec. 18, 2007. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0007]    Not applicable. 
       NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0008]    There is no joint research agreement in conjunction with this invention. 
       REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX 
       [0009]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0010]    (1) Field of the Invention 
         [0011]    This inventive concept is directed toward enhancing safety in residences and commercial establishments where the possibility of injury exists due to fingers of children or adults being caught in door closings. Each year approximately 30,000 people, both children and adults are rushed to hospital emergency rooms in the United States because they have accidentally crushed or amputated a finger. The two most common causative factors in severe finger injuries are (1) the use of power tools and (2) closing of doors. According to the National Center for Injury Prevention and Control (NCIPC) in Atlanta, Ga., children aged 4 and younger and men aged 55 and older are the two age groups found to be most at risk for these type injuries. It is estimated that over 1500 door-caused finger injuries are so severe that the injured person requires reconstructive surgery. Fifty-five percent of these accidents occur at home. Car doors and garage doors are also included in these statistics, along with finger injuries caused by revolving doors. 
         [0012]    There have been several types of finger guards or door guards marketed, the most common being some type of flexible blocking device attached to the vertical edge of the latching side of a door to prevent it from closing fully. Other devices include concepts such as “gate for doors,” which is an actual gate used in doorways, hallways, and at the top of stairs in order to prevent toddlers from going past a certain point or playfully opening or closing a co-located door. Practically all of these inventions are designed and marketed for the protection of children, but not specifically for adults, who are taller and heavier. 
         [0013]    Door guards, which are also known as hinge guards, anti-finger trapping devices, and/or finger guards, protect fingers in door hinges. A closing door can exert up to 40 tons per square inch of pressure between the hinges. Door guards normally cover the gap which exposes the hinges as a door is opened. The most common form of door guard is a length of rubber or other resilient material that attaches either to the trailing edge of a door, or to both the door and the frame, and is flexible enough to cover the hinged gap should the door be fully opened. 
         [0014]    (2) Description of the Related Art 
         [0015]    The prior art contains a number of door guards and protective devices, either for the hinged trailing edge or the latching, (leading) edge of a door. One notable example is in U.S. Pat. No. 2,184,259, where disclosures similar to embodiments of this invention are made. In particular, there is disclosed the design of a concave frame shape to accommodate the convex end of a door which pivots about a vertical axis defined by upper and lower pins. However, no claims to the safety features of this invention were made. 
         [0016]    U.S. Pat. No. 3,141,204 has a uniquely designed door jamb in which the side frame member has transversely movable or flexible pressure plates which will yield in the event an object such as a finger is caught between the edge of a closing door and the side frame. 
         [0017]    Several devices are designed to provide a protective shield or covering over the gap in the area of the door hinges when a door is opened. For example, U.S. Pat. No. 4,261,140 features a flexible, retractable shield overlying the front, or outward gap of the hinged area, and a flexible shield overlying the rear or inward gap at the door. This invention also features a door stop device mounted to the front surface of the door which, as the door is moved toward closed, said device is activated to drop into position and block the door from closing, thereby providing protection against injury which might occur between the leading edge of the door and the jamb. 
         [0018]    U.S. Pat. No. 4,290,233 features a “detachable finger protector for continuously closing the gap formed between the heel of the door and the abutting adjacent jamb surface whenever the door is opened.” This patent also provides for a device to cover and enclose the hinges of the door by a finger protecting safety shield. 
         [0019]    An elongated safety hinge which is extended horizontally outward from the door jamb is the primary feature of U.S. Pat. No. 5,076,017. Further, a resilient end cap is secured to the “swing” edge of the door in order to minimize the risk of fingers being injured if caught between the door stile and the door jamb. The invention also discloses latching rods extending from the upper and lower extremities of the door. 
         [0020]    U.S. Pat. No. 5,092,077 utilizes a variable geometry semi-rigid piece to attach to both the hinged vertical edge of the door and the door jamb. This provides finger protection in the hinged area along the length of the door. 
         [0021]    The gap between the hinge portion of a door and the door edge is protected by an elongated finger door guard device which automatically covers the hazardous gap when the door is opened in U.S. Pat. No. 5,765,311. A similar device is used in U.S. Pat. No. 6,141,909. 
         [0022]    U.S. Pat. No. 6,311,432 has a unique safety device designed to be fitted to the side of a door stile adjacent to the jamb, which device serves to sweep the zone between the jamb and the adjacent stile as the door is pivoted closed. The door jamb is also fitted with a pair of vertically extending shielding strips, serving to form a blocked safety area as the door swings into the closing zone. 
         [0023]    U.S. Pat. Nos. 6,434,888, 6,832,450, and 7,047,694 all have similar elongated hinge area door guards. 
       BRIEF SUMMARY OF THE INVENTION 
       [0024]    Several unique features of this inventive concept evidence the fact that safety and ease of operation are coordinated throughout the design. The basic invention is a Door Assembly comprised of a main door, which can be of a variety of sizes and materials, a four-sided doorframe for housing the main door via a major pivotal means, a leaf door, attached to the leading edge of the main door by a minor pivotal means, and a resilient padding which fills the exposed gap along the hinged side (or trailing edge) of the main door. 
         [0025]    An elongated rectangular portion of the leading edge of the main door is excised and the main door proximate the cutout is reinforced to support a pivoting function of the leaf door. The leaf door is a virtual miniature door designed to rotate, upon its own pivotal means, which may be an adequately tensioned spring mechanism. The pivotal axis of the leaf door is parallel to the leading edge of the main door. The leaf door normally remains flush with the main door, unless it is impeded by an object inserted at the inside front doorframe. The primary object of all the embodiments of this inventive concept is to produce a door that minimizes the danger of the fingers of a child, adult, or a small pet being (1) crushed between the leading edge of the main door and the doorframe, or (2) severely injured in the gap in the vicinity of what normally would be the hinged area, or trailing edge of a door. 
         [0026]    Several embodiments of the Door Assembly concept feature a main door with a rounded or concave trailing edge. With such trailing edge, an axle or concentric upper and lower dowels form the major pivotal means. The present inventive concept may also utilize a length of compressible elastomeric material to fill the longitudinal gap proximate the trailing edge of the main door, where hinges would normally be located. 
         [0027]    One aspect of the door assembly is the ability to latch the leaf door into the threshold of the doorframe as a security measure when the main door is fully closed. In a different embodiment, the main door cutout contains a lower ledge which can accommodate the latching of the leaf door, again as a security provision. When unlatched, the leaf door may rotate approximately 20 to 30 degrees by virtue of its minor pivotal means. 
     
    
     
       BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWINGS 
       Index to Components of Door Assembly 
         [0000]    
         
             1 . Main Door 
             2 . Upper Main Spindle 
             3 . Lower Main Spindle 
             4 . Main Spindles Rotational Axis 
             5 . Circular Upper Housing 
             6 . Circular Lower Housing 
             7 . Main Door Cutout 
             8 . Door Knob 
             9 . Dual Action Deadbolt 
             10 . Direction of Movement of Main Door 
             11 . Threshold of Frame 
             12 . Doorframe Exterior Exposure 
             13 . Doorframe 
             14 . Entry Side of Frame 
             15 . Leaf Door 
             16 . Leaf Door Upper Dowel 
             17 . Leaf Door Lower Dowel 
             18 . Leaf Door Pivotal Axis 
             19 . Leaf Door Upper Circular Notch 
             20 . Leaf Door Lower Circular Notch 
             21 . Leaf Door Security Rod 
             22 . Range of Movement of Leaf Door 
             23 . Side Strike Box 
             24 . Lower Strike Box 
             25 . Spring Mechanism for Leaf Door 
             26 . Vertical Deadbolt Pin 
             27 . Horizontal Deadbolt Pin 
             28 . Interior Surface of Main Door 
             29 . Exterior Surface of Main Door 
             30 . Resilient Padding 
             31 . Trailing Edge of Main Door 
             32 . Leading Edge of Main Door 
             33 . Upper Reinforced Ledge 
             34 . Lower Reinforced Ledge 
             35 . Receptacle for Security Rod 
             36 . Lower Strike Box 
             37 . Retracting Spring 
             38 . Strike Plate 
             39 . Upper Ball Bearing Assembly 
             40 . Lower Ball Bearing Assembly 
             41 . Revolving Wing 
             42 . Wing Leaf Door 
             43 . Power-Driven Shaft 
             44 . Upper Dowel 
             45 . Lower Dowel 
             46 . Upper Circular Metallic Notch 
             47 . Lower Circular Metallic Notch 
             48 . Spring Loading Device 
             49 . Wing Upper Ledge 
             50 . Wing Lower Ledge 
             51 . Revolving Door 
             52 . Doorframe Inner Top Surface 
             53 . Doorframe Outer Top Surface 
             54 . Doorframe Inner Rear Surface 
             55 . Doorframe Outer Rear Surface 
             56 . Doorframe Top Threshold 
             57 . Doorframe Bottom Threshold 
             58 . Doorframe Inner Front Surface 
             59 . Doorframe Outer Front Surface 
             60 . “U”-Spring Mechanism 
         
       
           [0088]      FIG. 1  presents a simplified view of the main door and a generic leaf door proximate the lower front quarter of the main door. 
           [0089]      FIG. 2  is an exploded of the doorframe, including the locations of supporting ball bearing assemblies. 
           [0090]      FIG. 3  is a view looking downward through the top of the doorframe and observing the enhanced main door, further depicting the upper ball bearing assembly. 
           [0091]      FIG. 4  is a side view of a cutaway of the top portion of the Door Assembly, showing the upper ball bearing assembly, strike plate, and the upper strike box. 
           [0092]      FIG. 5  gives a cutaway side view of the Door Assembly, showing the circular lower housing, lower ball bearing assembly, and the lower strike box. 
           [0093]      FIG. 6  presents a view of the “U” spring mechanism which may be utilized to operate the leaf door. 
           [0094]      FIG. 7  is a presentation of a bottom view looking upward through the threshold and observing the main door opened while the leaf door is unlatched and ajar from its flush position with the main door. 
           [0095]      FIG. 8  is a rendering of an embodiment wherein the leaf door revolves upon a lower ledge of the main door. 
           [0096]      FIGS. 9 ,  9 ( a ), and  9 ( b ) show a perspective rendering of an enhanced embodiment of the invention, including two vertical security rods, a horizontal dead bolt, and the receptacles for each of these devices 
           [0097]      FIG. 10  is a cutaway view of the operation and interrelationship among the upper, middle, and lower security rods as they are latched and/or unlatched. 
           [0098]      FIG. 11  presents an embodiment in which the main door contains upper and lower spindles which are embedded in, and aligned with, a rigid vertical rod, referred to as an “axle.” 
           [0099]      FIG. 11(   a ) is a top view showing the main axle-door and doorframe support element. 
           [0100]      FIG. 12  illustrates an embodiment of the leaf door concept in which all four wings of a revolving door are equipped with integral spring-actuated leaf doors. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0101]    It is important to present, initially, a generalized view and summation of the operating concept of this invention. Beginning with  FIG. 1 , there is shown a perspective view of a generic “main door”  1 , including a rectangular cutout  7 , said cutout  7  precisely sized to accommodate the leaf door  15 .  FIG. 2  presents an exploded view of the doorframe  13 . The threshold of the door frame  11 , doorframe inner rear surface  54 , outer top surface of door frame  53 , upper strike box  83 , strike plate  98 , and the location of upper and lower ball bearing assemblies,  39 ,  40 , respectively, are shown. 
         [0102]      FIG. 1  also depicts major pivotal means comprised of an upper main spindle  2  and a lower main spindle  3 , which define the rotational axis  4  about which the main door  1  revolves. The resilient padding  30  traverses the length of the doorframe inner rear surface  54 , said padding covering the gap which normally exposes the hinged area of a standard door. The padding  30  is attached to the doorframe inner rear surface  54  by an adhesive or other suitable means. The padding  30  serves to prevent the insertion of fingers in the space between the main door  1  and the doorframe inner rear surface  54 . 
         [0103]    Although not shown in  FIG. 1 , the bottom surface of the main door  1  and the doorframe top threshold  56  may be overlaid with a layer of grooved hard rubber material. The said material may be applied to the bottom surface of the main door  1  and the doorframe top threshold  56  such that the small grooves will run lengthwise and parallel along both surfaces with the result that the grooves are relatively interlocking with each other when the main door  1  is closed. This feature will further serve as a weather-tight barrier against the elements. 
         [0104]    The top of the frame  53  features a built-in circular upper housing  5 . This housing contains a ball bearing assembly designed to accept the upper main spindle  2 . An appropriate assembly may be comprised of spindle bearings or any other type of bearings particularly suitable for both rotational guidance of a shaft, and a moderate capacity for radial load bearing. The top frame member  53  is explained with more detail in  FIG. 7 , below. 
         [0105]      FIG. 3  illustrates a view of the Door Assembly looking downward through the top of the frame  73 . The main door  1 , or enhanced main door  61 , is shown closed and the leaf door security rod  21  has been unlatched, allowing the leaf door  15  to pivot slightly ajar. Should an object, such as a finger, become lodged between the leaf door  15  and the doorframe inner front surface  58 , the leaf door  15  is prevented from closing with its full weight and rigidity as it approaches doorframe inner front surface  58 , and thus severe injury is be avoided. Observing the leftmost portion of  FIG. 3 , the padding  30 ,  90  adhering to the doorframe inner rear surface  54  is depicted. The circular upper housing  5 ,  65 , which will contain the upper ball bearing assembly  39 , is also shown. 
         [0106]      FIG. 4  depicts a cutaway rendering of a side view of the top of the frame  73 . The enhanced main door  61  is presented in the closed position. Both the main latching rod  99  and the upper security rod  93  are latched into the strike plate  98  and the upper strike box  84 , respectively. The bottom end of the upper main spindle  62  is shown as anchored into the enhanced main door  61 . The main door&#39;s upper circular housing  65  is shown as it fits into the upper frame  73 . The said housing also contains the upper ball bearing assembly  79  which supports and guides the radial motion of the upper main spindle  62 . 
         [0107]    As we examine  FIG. 5 , a cutaway of the side view of the frame threshold  11  is shown, as well as contiguous portions of the concave mounting side of the frame  72  and the entry side of the frame  74 . The circular lower housing  66  is shown as it is embedded in the threshold  71 . This housing contains the lower ball bearing assembly  80 , which in turn provides load support for the enhanced main door  61 , radial stability for the lower main spindle  63 , and a relatively friction-free rotational platform for the lower main spindle  63 . The lower security rod  95  is depicted as being inserted into the lower strike box  96 , thus providing a secure latching condition for the door assembly. 
         [0108]    Continuing to examine  FIG. 5 , it is seen that the leftmost portion of the threshold  11  is constructed with a built-in circular lower housing  66 . This housing contains a customized ball bearing assembly  80  designed to accept the lower main spindle  63  and also support the weight and rotation of the enhanced main door  61 . An appropriate ball bearing assembly  80  may be comprised of any of a selection of axial spherical roller bearings, axial cylindrical roller bearings, or axial deep groove ball bearings. Each of these species of ball bearing assemblies has high load carrying capacity, excellent durability, and is suitable for guiding the lower main spindle  63 . 
         [0109]      FIG. 6  presents a pair of “U” springs  60  that are of practical consideration for use in the operation of the leaf door  15 ,  75 . The coil  111  of each of the U-springs  60  is partially welded to a vertical spring rod  112  which is affixed to a recess within the rounded leading edge  32  of the main door  1 ,  61 . The extended prongs  113  of each U-spring  60  are in turn welded to a mounting plate  114  which is attached by appropriate means to the leaf door  15 ,  75 . 
         [0110]      FIG. 7  illustrates the coordinated operation of the trailing edge of the door  32 , the main door  1 , and the leaf door  15 , as seen looking from the floor, upwards through the threshold of the frame  11 . The main door  1  is shown open and the leaf door  15  is depicted unlatched and lagging slightly behind the position of flush alignment with the main door  1 . The resilient padding  30  is shown compressed toward the interior surface  28  of the door. The main door  1  has been opened by pushing it about its rotational axis  4 , the lower line of said axis extending coaxially through the lower main spindle  3  and the circular lower housing  6 . 
         [0111]    When the main door  1  is pushed closed, in the direction of its arc of movement  10  shown, the leaf door  15  in turn may be pushed fully closed and flush with the main door  1 . The leaf door  15  may then be latched by a turn of the dual action deadbolt  9  pushing the leaf door security rod  21  downward into its fitted receptacle  36 , which is located in the threshold  11 . 
         [0112]      FIG. 7  demonstrates that, in the unlatched position, the leaf door  15  provides protection against accidental crushing of a finger which may be accidentally caught between the leading edge of the main door  32  and the inner front surface  58  of the doorframe. As the main door  1  closes, the leaf door  15 , being unlatched, lags slightly behind the surface of the main door  1 , and may make blunted contact with the finger. As the contact takes place, it will be with substantially reduced force since the spring mechanism  25  does not permit the leaf door  15  to contact the inner front surface  58  of the doorframe with the same rigidity as the main door  1 . Thus, serious injury is avoided. Once the main door  1  is safely closed, the leaf door  15  may then be secured by operation of the dual action dead bolt lock  9  as it activates the leaf door security rod  21 . 
         [0113]      FIG. 8  depicts an alternative embodiment of the leaf door  15  and a different method of attachment to the main door  1 . The embodiment in  FIG. 8  depicts an alternative arrangement whereby the leaf door  15  is mounted between an upper reinforced ledge  33  and a lower reinforced ledge  34  within the main door cutout  7 . For clarity, the leaf door  15  is shown separated from its junction with the main door  1 . As a means of security, a leaf door latch (not shown) may be used to operate, in a vertical orientation, an internal leaf door security rod  21  which snugly fits into a lower strike box  36  within the threshold  11  when the leaf door  15  is closed flush with the main door. 
         [0114]    Also pictured in  FIG. 8  is the leaf door upper circular notch  19 , which is built into the upper portion of the main door cutout  7  so as to provide both a form-fitted recess and rotational stability for the leaf door upper dowel  16 . The leaf door lower circular notch  20  is cut into the main door lower reinforced ledge  34  and serves to accommodate and provide rotational stability for the leaf door lower dowel  17 . As the leaf door  15  is operated to and from the latched and/or unlatched positions, it pivots about its pivotal axis  18 , which axis is defined by the co-located centerlines of the upper and lower circular notches  19 ,  20 . 
         [0115]      FIG. 8  shows an effective location of one or more spring mechanisms  25  for the leaf door  15 , which is a position firmly affixed to mid-length of the main door cutout  7 . It is anticipated that a number of variations of spring means will prove to be effective as the inventive concept is modified. Another possible spring mechanism  25  includes the use of matching upper and lower helical torsion springs. One end of the upper helical torsion spring affixed to the upper circular notch  19  and one end of the lower helical torsion spring affixed to the lower circular notch  20  of the leaf door  15 . The remaining end of each respective helical torsion spring will be attached at a point on the leaf door  15  so as make the axis of each helical torsion spring co-located with the pivotal axis  18  of the leaf door  15 . 
         [0000]    Door Assembly with Enhanced Security Features 
         [0116]    In referring to several of the figures, enhancements of the basic embodiment of the Door Assembly are shown. A supplemental Index to Components follows:
     61 . Enhanced Main Door     62 . Upper Main Spindle     63 . Lower Main Spindle     64 . Main Spindles Rotational Axis     65 . Circular Upper Housing     66 . Circular Lower Housing     67 . Main Door Cutout     68 . Door Knob     69 . Latching Deadbolt     70 . Direction of Movement of Main Door     71 . Frame Threshold     72 . Concave Mounting Side of Frame     73 . Top of Frame     74 . Entry Side of Frame     75 . Leaf Door     76 . Leaf Door Upper Dowel     77 . Leaf Door Lower Dowel     78 . Leaf Door Pivotal Axis     79 . Upper Ball Bearing Assembly     80 . Lower Ball Bearing Assembly     81 . Tubular Housing     89 . Exterior Surface of Main Door     90 . Resilient Curtain/Padding     91 . Convex Trailing Edge of Door     92 . Leading Edge, Main Door     93 . Upper Security Rod     94 . Middle Security Rod     95 . Lower Security Rod     96 . Lower Strike Box     97 . Retraction Spring     98 . Strike Plate     99 . Main Latching Rod     100 . Doorframe Inner Curvature     101 . Main Axle-Door     102 . Upper Spindle     103 . Lower Spindle     104 . Casing     105 . Bolt     106 . Threaded Shaft     107 . Doorframe Support Element     108 . Axle     109 . Inner Angle  82 . Left Mechanical Linkage  110 . Open Position  83 . Right Mechanical Linkage  111 . Coil  84 . Upper Strike Box  112 . Spring Rod  85 . Spring Mechanism for Leaf Door  1113 . Prong  86 . Vertical Deadbolt Pin  114 . Mounting Plate  87 . Horizontal Deadbolt Pin  88 . Interior Surface of Main Door   
 
         [0159]    As we view  FIGS. 9 ,  9 ( a ), and  9 ( b ), security latching mechanisms of an embodiment of the door assembly are presented. The leaf door  15 ,  75  may, during normal use, be latched to the main door  1 ,  61 , by means of the dual action deadbolt  69 . The dual action deadbolt  69  is connected to an upper security rod  93  and a horizontal deadbolt pin  87 .  FIG. 10  also presents close-up view of the functioning of the various mechanisms. When the dual action deadbolt  69  is turned to the latched position, it will simultaneously force the middle security rod  94  downward, forcing the lower security rod  95  (also referred to as the leaf door security rod  21  in the basic embodiment) into the lower strike box  96  and simultaneously pushing the horizontal deadbolt pin  87  into the side strike box  23  (not shown). The leaf door security rod receptacle  96  is cut into the threshold  71  and thus provides an extra measure of security and leaf door stability. 
         [0160]    The embodiment shown in  FIGS. 9 ,  9 ( a ), and  9 ( b ) operates in much the same manner as the basic embodiment. The most noticeable modification in the enhanced embodiment as shown is the inclusion of an upper security rod  93 , middle security rod  94 , and lower security rod  95 . With the enhanced main door  61  shown partially open, the upper  93 , middle  94 , and lower security rod  95  are all indicated by dashed lines. In the operating embodiment of this invention, metal tubes, slightly larger in diameter than the aforementioned security rods will envelope the entire length of each of the said rods. The tip of the main latching rod  99  is shown extending above the top edge of the door. This is the normal functional position of the main latching rod  99  whether the enhanced main door  61  is open or closed. The door knob  8 ,  68  controls the operation of the main latching rod  99  in a manner comparable to the spindle of a conventional doorknob controlling the sidewise-oriented deadbolt in a doorknob and strike plate combination. 
         [0161]    For illustrative purposes only, the upper security rod  93  and the lower security rod  95  are both shown extended into their “latched” position. However, the enhanced main door  61  may only be latched for security purposes when the door is fully closed. After closing the enhanced main door  61 , the latching deadbolt  69  is rotated clockwise, causing mechanical linkages connected to both the upper security rod  93  and the lower security rod  95  to be displaced. Movement of the linkages forces the upper security rod  93  upward into the upper strike box  84 , and the lower security rod  95  into its lower strike box  96 . 
         [0162]      FIG. 10  presents a closer view of the operation of the upper and lower security rods  93 ,  95 . Shown is a cutaway view of the relevant portions of the enhanced main door  61  and the leaf door  75  with both the upper and lower security rods  93 ,  95  in the latched position. The upper security rod  93  and the lower security rod  95  are each enclosed in similar tubular housings  81 ,  81 ( a ),  81 ( b ) to guide their vertical movement within the enhanced main door  61 . The latching deadbolt  69  is pictured as having been turned clockwise to its vertical position. This action has caused the left mechanical linkage  82  to move the upper security rod  93  into the upper strike box  84  (not shown). This position of the latching deadbolt  69  has also caused the right mechanical linkage  83  to move a middle security rod  94  downward against the lower security rod  95 , thereby forcing the lower security rod  95  into the lower strike box  96 . Further, the latching position of the latching deadbolt  69  has also placed the retraction spring  97  into tension. 
         [0163]    Upon turning the latching deadbolt  69  counter-clockwise to its horizontal unlatched position, the left mechanical linkage  82  retracts the upper security rod  93  from the upper strike box  84  and causes the rod  93  to be stowed within the enhanced main door  61 . Simultaneously, the right mechanical linkage  83  retracts the middle security bolt  94  upward, which relieves the downward pressure on the lower security rod  95 . Thereupon, the retraction spring  97  compresses and pulls the lower security rod  95  out of the lower strike box  96 . The leaf door  15 ,  75  is then free to pivot in its injury-preventing mode. 
       Other Embodiments and Applications of the Door Assembly 
       [0164]    Again referring to  FIG. 1 , a number of modifications and additions to the basic door assembly can be projected. For instance, a different embodiment of this invention would entail increasing the relative size of the leaf door  15  by extending its length vertically so as to encompass all, or a portion of, the leading edge of the main door  1  above the door knob or handle. The increased size of the leaf door  15  may require a series of spring mechanisms  25  in order to provide sufficient tension, symmetry, and balance to properly position the leaf door  15  throughout the operating range of the enhanced main door  1 . 
         [0165]    In reviewing FIG.  8 ., it must be noted that, although not shown in the present embodiments, design features may be incorporated whereby both the upper circular housing  65  and the lower circular housing  66  are constructed with a “quick release” feature built into the frame which feature will allow an effective means of removal of either housing for lubrication of the components or replacement of the ball bearing assemblies  79 ,  80 . 
         [0166]    A variety of spring means  25  ( FIG. 2 .) may be incorporated into the different embodiments of this inventive concept. One type of spring mechanism consists of a continuous spring-loaded hinge, similar to a piano hinge. This hinge runs the entire length of the pivoting edge of the leaf door  15  and thus serves to define the leaf door pivotal axis  18 . A second possible type of spring is the commonly used auto-locking bifold spring which also can operate effectively in this invention when it is appropriately attached to both the enhanced main door  61  and the leaf door  15 . 
         [0167]    As another consideration for effective functioning of the invention, manufacture of the door assembly may be enhanced by incorporating miniature spring-loaded cabinet hinges or Euro-hinges as the spring mechanism  25  in the design of the leaf door  15 . As further consideration,  FIG. 6  presents a combination of two “U”-springs connecting the leaf door  15  and the enhanced main door  61   
         [0168]    A further improvement to this inventive concept comprises the application of an optimum thickness of rubberized or plastic-type material along the entire leading edge  32  of the main door and also application of the same material along the entry side of the doorframe  14 . Such material further serves the primary object of the invention, which is to minimize the possibility of serious injury in the event a finger is caught between the leaf door  15  and the entry side of the doorframe  14 . 
       Embodiment 
     Door Assembly With Integral Axle 
       [0169]    In referring to  FIG. 11 , an embodiment of this inventive concept is shown with a main axle-door  101  constructed with an integral door axle  108  and the previously disclosed leaf door  75 . The door axle  108  is of a diameter slightly larger than the main axle-door  101  thickness and additionally has embedded in it, at opposite ends, the spindle  102  and lower spindle  103  of the main axle-door  101 . The door axle  108  is of sufficient strength and rigidity as to provide a durable and steady axis for opening and closing of the main axle-door  101 . Owing to the increased diameter of the door axle  108  relative to the thickness of the main axle-door  101 , a variable-shaped doorframe  107  is required to support the pivotal functioning of the main axle-door  101 , in which the inner back surface of the previously disclosed doorframe is modified. A top view of the cross-section of such modified inner back surface is shown in  FIG. 11 . The door axle  108  may further be tightly enclosed in a casing  104 , composed of metal or other suitable material. The casing  104  may be press-fitted against the door axle  108  or secured with bolts  105  along the length of the main axle-door  101 . The casing enhances endurance, security, and all-weather protection. 
         [0170]    In viewing  FIG. 11(   a ), a top view of the main axle-door  101  and variable-shaped doorframe  107  is presented. The upper spindle  102  and a portion of the main axle-door  101  are shown in the door closed position. The dashed lines indicate the position of the main axle-door  101  were it fully opened  110 . In the fully open position  110  sufficient clearance from the doorframe support element  107  is provided by a beveled angle  109 , which allows sufficient room for pivoting of the main axle-door  101 . 
         [0171]    It can be seen that, as the main axle-door  101  revolves open or closed, the door axle  108  rotates in close proximity to the inner curvature  100  of the doorframe support element  107 . This close spacing between the main door axle  108  and the inner curvature  100  of the doorframe support element  107  serves a critical safety function in that the close tolerance prevents the insertion of a finger into what would normally have been the gapped hinged area of a conventional door. 
       Office and/or Commercial Embodiment 
       [0172]    In  FIG. 12 , a commercial application of this invention is shown wherein each of the four wings  41 , of a revolving door  51  is designed to function utilizing the leaf door concept. This embodiment of the safety door design is particularly applicable to public or commercial buildings equipped with revolving doors. As shown in  FIG. 12 , each of the wings  41  is attached to a common door shaft  43 . The door shaft  43  may be electrically or mechanically powered to simultaneously rotate the wings, normally counter-clockwise, in response to pedestrian traffic moving through the door. Each wing  41  contains a leaf door  42 , which may pivot, by means of an upper dowel  44  and a lower dowel  45  embedded in the respective leaf door  42 , about an axis running concentrically through each paired upper and lower dowel  44 ,  45 . Each upper dowel  44  is contained in an upper circular metallic notch  46  and each lower dowel  45  rests in a lower circular metallic notch  47 . The circular notches are built into the respective upper ledge  49  and lower ledge  50 , with each ledge being an integral part of the structure of each wing  41 . 
         [0173]    A plurality of spring-loading devices  48  are regularly spaced along the junction of each leaf door  42 , and its respective wing  41 . The spring-loading devices  48  assist in moderating the closing force of their respective leaf doors  42  in the event an obstruction is encountered during closing of the revolving door  51 . Each leaf door  42  is generally 75% to 90% of the height of its respective wing  41 . 
         [0174]    Having described the basic and the enhanced embodiments of this Safety Door Assembly, it is believed that other modifications, improvements, and changes will be suggested to those skilled in the art in view of the teachings set forth herein. It is therefore to be understood that all such variations, improvements, and changes are encompassed within the scope of the present invention.