Patent Abstract:
Disclosed is a door assembly comprising a custom-built doorframe housing a main door which carries an integrally mounted, rectangularly-shaped leaf door. The trailing edge of the main door rotates about a vertical axis which is parallel to, and proximate the inner rear surface of the doorframe. The leaf door is rotatably attached, by a spring mechanism, to a cutout excised from the leading edge of the main door. As the main door rotates about its vertical axis, the leaf door is restrained, by tension of the spring mechanism, 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 may be abutted against elastomeric material affixed to the inner rear surface of the doorframe, thereby preventing the insertion of fingers into what otherwise would be a hazardous gap.

Full Description:
CROSS-REFERENCES TO RELATED APPLICATIONS AND PRIORITY CLAIM 
     This application claims the benefit of provisional patent application No. 61/008,027, filed on Dec. 18, 2007, and further claims the benefit of non-provisional application Ser. No. 12/316,631 filed on Dec. 15, 2008. The content, disclosures, and descriptions in each of these applications are incorporated herein by reference. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
     There is no joint research agreement in conjunction with this invention. 
     REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     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. 
     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. 
     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. 
     (2) Description of the Related Art 
     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. 
     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. 
     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. 
     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. 
     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. 
     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. 
     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. 
     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. 
     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 
     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, and a leaf door, attached to the leading edge of the main door by a minor pivotal means. A further developed embodiment of the inventive concept includes a resilient padding which fills the exposed gap along the pivotal side (or trailing edge) of the main door. 
     An elongated rectangular portion of the leading edge of the main door is excised and the section of the main door where the cutout is made 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 minor pivotal means, which may be an adequately tensioned spring mechanism. The pivotal axis of the leaf door is vertically oriented and 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, in which event, the leaf door is forced open slightly, thereby negating the full impact of the closing force on the object. 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. 
     Several embodiments of the door assembly concept may feature a main door with a rounded or concave surface the entirety of the trailing edge. With such trailing edge, an axle or concentric upper and lower dowels form the major pivotal means. 
     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. 
     INDEX TO COMPONENTS OF BASIC DOOR ASSEMBLY 
     
         
           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 Doorframe 
           12 . Doorframe Exterior Exposure 
           13 . Doorframe 
           14 . Entry Side of Frame 
           15 . Leaf Door 
           15 ( a ) Leading edge of 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 
           31 ( a ) Top Surface of Main Door 
           32 . Leading Edge of Main Door 
           32 ( a ) Bottom Surface 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 
           48 ( a ) Not applicable 
           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 
       
    
    
    
     
       BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWINGS 
         FIG. 1  presents a simplified view of the main door and a generic leaf door attached to the lower front quarter of the main door. 
         FIG. 2  is a semi-exploded view of the doorframe, including the locations of supporting ball bearing assemblies. 
         FIG. 3  is a side view of the top portion of the door assembly, showing the upper ball bearing assembly, strike plate, and the upper strike box. 
         FIG. 4  is a view looking downward through the top of the doorframe and observing the enhanced main door, further depicting the upper ball bearing assembly. 
         FIG. 5  gives a side view of the lower segment of the door assembly, indicating positions of the circular lower housing, lower ball bearing assembly, and the lower security rod. 
         FIG. 6  presents a view of a pair of “U” spring mechanisms which may be utilized to operate the leaf door. 
         FIG. 7  is an illustration of a view looking upward through the threshold with the main door partly open and the leaf door unlatched from its normal flush relationship with the main door. 
         FIG. 8  is a rendering of an embodiment wherein the leaf door revolves upon a lower ledge of the main door. 
         FIGS. 9 ,  9 ( a ), and  9 ( b ) show a perspective rendering of the latching mechanisms associated with an enhanced main door, including two vertical security rods, and a dual-action deadbolt. 
         FIG. 10  is a cutaway view depicting the operation of the upper, middle, and lower security rods. 
         FIG. 11  presents an embodiment of a main “axle-door” in which the door contains upper and lower spindles which are embedded in, and co-axially aligned with, a rigid vertical rod, referred to as an “axle.” 
         FIG. 11(   a ) is a top cutaway view showing the main axle-door and doorframe support element, as seen from the cutaway line B-B. 
         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 
     Initially, it is necessary to clarify the principle terms and phrases used in referring to or describing the function of this inventive concept. The term “doorframe”  13  means a generally rectangular-shaped assemblage comprising four oblong panels which have been joined together. These four panels consist of eight surfaces, which are more precisely depicted by reference to  FIG. 2 . Proceeding in a clockwise fashion, the doorframe  13  is described as follows: 
     (1) a first panel comprising a vertically-oriented oblong structure having a flat outer rear surface  55  and a concave inner rear surface  54 ; 
     (2) a second panel comprising a horizontally-oriented oblong structure having a flat outer top surface  53  and a flat inner top surface  52 ; 
     (3) a third panel comprising a vertically-oriented oblong structure having a flat outer front surface  59  and a flat inner front surface  58 ; and 
     (4) a fourth panel comprising a horizontally-oriented oblong structure having a flat bottom threshold  57  and flat top threshold  56 . 
     The endmost parts of each of the foregoing panels are joined orthogonally, as illustrated, so that their inner surfaces form four inner corners, or junctions. The interior perimeter of the doorframe consists of a dimension approximately equal to the total exterior perimetral dimension of the main door. A further design feature of the door assembly includes a resilient padding  30  which may be attached to the entire surface of the concave inner rear surface  54  of the doorframe. 
     As further clarification of the features of the door assembly, the term “leading edge,” as applicable to either the main door or the leaf door, means that portion of the door which, when closed, abuts the doorframe inner front surface. The term, “trailing edge” means that portion of the surface of either the main door or the leaf door which contains or is attached to the major pivotal means or the minor pivotal means, respectively. When the main door  1 ,  61  is fully closed within the doorframe  13 , the leading edge of the main door abuts the doorframe inner front surface  58 , the top surface (horizontally-oriented) of the main door  1 ,  61  abuts the doorframe inner top surface  52 , and the bottom surface (horizontally-oriented) of the main door  1 ,  61  abuts the doorframe top threshold  56 . 
     A generalized view and summation of the operation of this inventive concept can be presented, 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 . The cutout is further defined by a “horizontal segment” and a “vertical segment.” Moving to  FIG. 2 , there is illustrated 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. 
       FIG. 1  also depicts major pivotal means comprised of an upper main spindle  2  and a lower main spindle  3 , which define the main spindles rotational axis  4  about which the main door  1  revolves. A semi-compacted material, forming a resilient padding  30 , traverses the length of the doorframe inner rear surface  54 , said resilient padding  30  filling the gap which is normally exposed at the hinged area of a standard door. The resilient padding  30  is attached to the doorframe inner rear surface  54  by an adhesive or other suitable means. The resilient padding  30  serves to prevent the insertion of fingers in the space between the trailing edge  31  of the main door  1  and the doorframe inner rear surface  54 . 
     Although not shown in  FIG. 1 , the bottom surface  32 ( a ) of the main door  1  and the doorframe top threshold  56  may be overlaid with a layer of grooved hard rubber material. The hard rubber material may be applied to the bottom surface  32 ( a ) of the main door  1  and the doorframe top threshold  56  such that the small grooves of the hard rubber material will run lengthwise and parallel along both surfaces. Thereby, 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. 
     The doorframe features a built-in circular upper housing  5 . The circular upper housing  5  is structured so as to contain a ball bearing assembly designed to accept the upper main spindle  2 . An appropriate ball bearing assembly may be comprised of spindle bearings or any other type of bearings particularly suitable for both rotational guidance of a shaft, and exhibiting a moderate capacity for radial load bearing. The doorframe inner top surface  52  and doorframe outer top surface  53  are shown in a more advanced embodiment of the inventive concept, as detailed in  FIG. 3  and  FIG. 4  herein. 
     In order to describe a practical operating system for the door assembly, including latching of the main door  1  and leaf door  15 , the reader is now referred to  FIGS. 9 ,  9 ( a ), and  9 ( b ). This set of drawings illustrates an enhanced main door  61  along with compatible latching mechanisms. 
     In viewing  FIGS. 9 ,  9 ( a ), and  9 ( b ), enhancements to the basic embodiment of the door assembly are shown. The following is a supplemental index to components of the enhanced main door  61  and other advanced embodiments of the basic door assembly:
       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     82 . Left Mechanical Linkage     83 . Right Mechanical Linkage     84 . Upper Strike Box     85 . Spring Mechanism for Leaf Door     86 . Vertical Deadbolt Pin     87 . Horizontal Deadbolt Pin     88 . Interior Surface of Main Door     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     110 . Open Position     111 . Coil     112 . Spring Rod     113 . Prong     114 . Mounting Plate     115 . Leading Edge of Leaf Door     116 . Trailing Edge of Leaf Door     117 . Top of Leaf Door     118 . Bottom of Leaf Door   

     The embodiment of the door assembly 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 , a middle security rod  94 , a lower security rod  95 , and a dual action latching deadbolt  9 ,  69 . With the enhanced main door  61  shown partially open, as in  FIG. 9 , the upper  93 , middle  94 , and lower security rod  95  are all indicated by dashed lines. In the operating embodiment of the door assembly, metal tubes, slightly larger in diameter than the aforementioned security rods will enclose the entire length of each the upper, middle, and lower security rods  93 ,  94 , and  95 . 
     As we view  FIGS. 9 ,  9 ( a ), and  9 ( b ), security latching mechanisms applicable to the enhanced main door  61  are presented. The leaf door (either  15  or  75 ) may be latched to the main door  1 ,  61 , by means of the latching deadbolt  69 . The dual action deadbolt  69  is connected to an upper security rod  93 , a middle security rod  94 , and a horizontal deadbolt pin  87 . For further clarification,  FIG. 10  also presents close-up views of the functioning of these components. When the latching deadbolt  69  is turned to its “latched” position, it will simultaneously move 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 a lower strike box  96 . The lower strike box  96  (shown in  FIG. 5  and  FIG. 10 ) is built into the frame threshold  11 ,  71  to provide an extra measure of security and leaf door stability. This turning of the latching deadbolt  9 ,  69  also simultaneously pushes the horizontal deadbolt pin  87  into a side strike box  23  (not shown) built into the doorframe inner front surface  58 . 
     To secure the upper portion of the enhanced main door  61 , a main latching rod  99 , operated by an industry standard doorknob  8 ,  68  is shown in  FIG. 9 . The upper end of the main latching rod  99  is shown in  FIG. 9(   a ), extending above the top surface  31 ( a ) of the enhanced main door  61 . This is the normal operational position of the main latching rod  99 , whether the enhanced main door  61  is open or closed. As the enhanced main door  61  is pushed to the closed position, the upper end of the main latching rod  99  engages a strike plate  98 . 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 operating a horizontally-oriented deadbolt in a doorknob and strike plate combination. 
     To further illustrate the functioning of the upper security rod  93  and the lower security rod  95 , we may refer to  FIG. 10 . The upper security rod  93  and the lower security rod  95  are both shown extended into their “latched” positions by virtue of operation of the latching deadbolt  9 ,  69 . 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  82 ,  83  connected to the upper security rod  93  and the lower security rod  95 , respectively, to be displaced. Movement of the mechanical linkages  82 ,  83  forces the upper security rod  93  upward into the upper strike box  84  (shown in  FIG. 9 ), and the lower security rod  95  into its lower strike box  96 . 
     In viewing  FIG. 3 , there is depicted a rendering of a side view of the upper segment of the door assembly with the enhanced main door  61  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 top of the frame  73 . The upper circular housing  65  housing also contains an upper ball bearing assembly  79  which supports and guides the radial motion of the upper main spindle  62 . 
       FIG. 4  illustrates a view of the door assembly looking downward through either the top of the doorframe  73 , or the doorframe outer top surface  53 , as depicted by cross-sectional line A-A. The main door  1 , or enhanced main door  61 , is shown closed. 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 contains the upper ball bearing assembly  39 , is also shown. 
     In viewing  FIG. 5 , the lower segment of the door assembly is shown. The circular lower housing  66  is shown as it is embedded in the doorframe threshold  11 ,  71 . The circular lower housing  66  contains the lower ball bearing assembly  80 . The lower ball bearing assembly 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 enhanced main door  61 . 
     Continuing in the examination of  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 . 
       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 . 
       FIG. 7  illustrates the coordinated operation of the leading edge  32 , of the main door, the main door  1 , and the leaf door  15 , as seen looking from the floor upwards through the doorframe bottom threshold  57 . The main door  1  is shown partly open. The leaf door  15  is illustrated with the leaf door security rod  21  unlatched, and for demonstrative purposes only, the leaf door  15  is shown lagging slightly behind its normal position of flush alignment with the main door  1 . The resilient padding  30  is shown compressed toward the trailing edge of the main door  31 . 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  (not shown). 
     When the main door  1  is pushed closed, in the direction of its arc of movement  10 , the leaf door  15  also travels in its normally flush relationship with the main door  1 . Once the main door  1  is fully closed the leaf door  15  may then be latched by a turn of the dual action latching deadbolt  9  (not shown) pushing the leaf door security rod  21  downward into its fitted receptacle  36 , which is located in the threshold  11 . These operations are more fully depicted in  FIG. 8 . 
       FIG. 7  also serves to demonstrate that the leaf door  15  provides protection against accidental crushing of, for example, 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  makes 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 . In fact, the main door  61  may continue its travel to become fully flush with the doorframe inner front surface  58 . Thus, the leaf door  15  has prevented serious injury. Assuming normal door operation, and not contact having been made, once the main door  1  is fully closed, the leaf door  15  may then be secured by operation of the dual action dead bolt lock  9  as it moves the leaf door security rod  21  downward. 
     As we move to  FIG. 8 , an alternative embodiment of the leaf door  15  is shown, along with a different method of attachment to the main door  1 . The embodiment in  FIG. 8  depicts an a mechanical 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 doorframe threshold  11  when the leaf door  15  is closed flush with the main door. 
     Also pictured in  FIG. 8  is a 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 . 
       FIG. 8  shows an effective location of one or more spring mechanisms  25  for retention of 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 . 
       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 , 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 . The latched position of the latching deadbolt  69  has also places the retraction spring  97  into tension, which, in turn, forces the lower security rod  95  to remain inserted into the lower strike box  96 . 
     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 with the normal closing of the main door  1 ,  61 . 
     Other Embodiments and Applications of the Door Assembly 
     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 . 
     Referring again to  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 . 
     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 . 
     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   
     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 
     In referring to  FIG. 11 , an embodiment of this inventive concept is shown with a major pivotal means comprising 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, a 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. 
     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 . 
     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 
     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 . 
     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 . 
     Having described the basic and the enhanced embodiments of the door assembly inventive concept, 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.

Technology Classification (CPC): 4