Abstract:
To cause a door from being forced open or broken to gain access, a safety door comprises a central actuator and a plurality of bars radially extending at spaced apart locations from said central actuator sufficient in number and spacing to reinforce substantially the entire door. The central actuator is pivotally mounted within the door and each of the plurality of bars has one of its ends pivotally mounted to the actuator to cause the bars to be retracted or extended by rotation of the actuator. There are at least four bars with at least one bar extending in each of the four sides of the door framework.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to safety doors and more particularly to doors that resist forced entry from outside such as for example by forcing a deadbolt that is holding the door to the doorway frame to release or forcing the hinges from the door or doorway frame. 
     It is known to utilize multiple spaced apart deadbolts that resist forcible entry. This prior art technique has several disadvantages, such as for example: (1) the deadbolts only protrude a short distance into the frame of the door and thus can be forced free; (2) it is time consuming and inconvenient to individually move the deadbolts into place; and (3) the hinges can be forced out of the frame or the center of the door can be broken into such as by an axe. 
     U.S. Pat. No. 5,911,763 discloses a central actuator that moves a plurality of deadbolts into place at spaced apart locations around the periphery of the door through individual linkages, thus reducing the inconvenience of moving individual deadbolts into place one at a time. However, the lock disclosed in this patent relies upon linkages near the deadbolts at the periphery of the door that activate the three individual deadbolts and the deadbolts have only a short length within the door. It has several disadvantages, such as: (1) there are no deadbolts on the hinge side of the door so there are only a few short screws holding this side of the door in place against an impact that may pull the screws holding the hinges free; and (2) each of the linkage mechanisms includes three pivot points from the central actuator and provides little support for the door itself. Thus, in the case of some doors, an axe may be used to break the door itself. 
     It is known to use bars mountable on the inside of the door and held at several locations so that they extend across the door. While these bars provide overall strength, it is time consuming to put them in place and remove them when locking or unlocking the door. Moreover, they are unsightly. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the invention to provide a novel safety door. 
     It is a further object of the invention to provide a novel method for securing a door. 
     It is a further object of the invention to provide a novel door that resists forced entry from impact such as kicking, hitting with a sledge hammer or prying with crowbars or the like. 
     It is a still object of the invention to provide a door that resists entry by cutting or penetrating means such as saws and blowtorches and the like. 
     It is a still further object of the invention to provide a novel door with sufficient strength to resist entry over the entire entrance and yet may be opened and closed in a normal manner. 
     It is a still further object of the invention to provide a novel safety door without excessive external appliances such as extra cages or bars or the like that must be individually placed to prevent easy entry. 
     It is a still farther object of the invention to provide a relatively inexpensive yet strong safety door. 
     It is a still further object of the invention to provide a safety door that can be tailored to the needs in terms of strength and ability to easily lock and unlock it. 
     In accordance with the above and further objects of the invention, the safety door includes a central actuator and a plurality of bars extending substantially radially from the centrally located actuator sufficiently far to protrude into the frame of the door. In the preferred embodiment, the centrally located actuator is substantially cylindrical and rotatably mounted to a central location on the door. It pivotably receives one end portion of each of the bars at spaced apart locations. A turn of the centrally located actuator through a relatively short number of degrees forces the bars into the frame or withdraws them from the frame of the door. There are at least four radially extending bars and preferably six radially extending bars relatively evenly annularly spaced about the centrally located actuator so that substantially the entire door is reinforced by the bars and the bars extend a substantial distance into the doorway frame. 
     The door itself may be fabricated of any of several different materials including metal with a fire-resistant internal filling or a wooden frame with an internal powder filling or be entirely wooden. It has been found that it is most economical for the door to contain a large percentage of wood because this slows steel cutting saws. The door should also be sufficiently solid to support the centrally-located actuator and the radially-extending bars. For this purpose, the core of the door must be capable of being drilled and routered at least over a substantial area to allow placement of the component parts of the actuator and bars. One of the less expensive types of such doors is a frame filled with pressed wood particles. Cores of wood are hereinafter at times referred to as wooden door cores. 
     In fabricating the door, the door may be placed horizontally on a surface such as a table top. Drills on runners may be attached to the table or other surface and then caused to drill holes radially inwardly for the bars. At a central location where the drilled holes meet, an opening must be drilled through the plane of the door to support the rotatably mounted actuator on the inside of the door. In the preferred embodiment, the bars are internal to the door but it is possible to mount them externally by other slidable means on the inside of the door. However, in the preferred embodiment, access to the locking mechanism is provided only from inside the door and not from the external side. The openings for the bars can be accomplished with a router by forming the radial slots or by drilling. They should be slightly larger in at least one radial direction than the bars since they will move laterally to a slight extent as well as radially. 
     In the preferred embodiment, the central actuator is wheel-shaped and includes circumferentially spaced-apart metal pins perpendicular to the plane of the door. Each of the pins connects the opening in an end portion of a corresponding rod to a circumferentially spaced pin opening in the actuator. Preferably, there are four or more such pins and six or more rods. The radial movement of the pins with the centrally located actuator moves the rods outwardly and inwardly. The end plate on the wheel conceals the pins and the end connections in the preferred embodiment. In one embodiment, a handle is provided to actuate the wheel from the outside. The handle may contain a lock or may be removable to provide security. 
     Two problems had to be solved to provide an easy to use, adaptable safety door. 
     Firstly, because the bars that serve as deadbolts and reinforcement for the door are actuated by a rotary actuator, they move both longitudinally and at an angle to their longitudinal axes within a solid door in a plane parallel to the doorway. Thus the door must include unsymmetrical openings in the door, door frame and floor with space at an angle to the longitudinal axes of the rods within a plane parallel to the doorway to permit movement of the bars. Secondly, the actuator must be easily rotated by hand even though it may move several long bars along frictional paths in some applications. Once these two unobvious problems were appreciated, they were solved by designing the safety door so that a minor amount of rotation in degrees would move a sufficient number of bars a sufficient distance into the doorway frame and/or floor to provide the required strength and an adequate mechanical advantage was obtained by proper selection of the actuator diameters. The diameters are the diameter of the circle of rotation of the handle of the actuator and the circle of rotation of the driving element for the bars. 
     From the above summary, it can be understood that the safety door and method of securing a door of this invention has several advantages, such as: (1) it has overall strength so as to resist battering by any mechanisms at any place; (2) it is difficult to locate and to break the points of attachment of the door and the frame; (3) the points of attachment and reinforcement are throughout the periphery of the door and within the overall area of the door so as to provide relatively few weak portions; (4) it is easy to operate the door in a normal manner; and (5) the door is relatively inexpensive. Even with cutting the rods, the locking arms will extend into the frame, thus preventing opening. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above noted and other features of the invention will be better understood from the following detailed description when considered in connection with the accompanying drawings in which: 
         FIG. 1  is a simplified fragmentary elevational view of a safety door, doorway frame and building partly sectioned in accordance with an embodiment of the invention; 
         FIG. 2  is a simplified, fragmentary, partly-sectioned side view of an actuator mounted within the two faces of a door and having rods attached to the actuator for movement thereby as utilized in the safety door of  FIG. 1  in accordance with an embodiment of the invention; 
         FIG. 3  is a fragmentary, exploded perspective view of a portion of the actuator end plates, one of the posts and one of the rods used in the embodiment of  FIG. 1 ; 
         FIG. 4  is a simplified perspective view of a rod, end plates showing the parts of  FIG. 3  assembled together; 
         FIG. 5  is a simplified fragmentary exploded perspective view of an actuator used in the embodiment of  FIG. 1  in accordance with an embodiment of the invention; 
         FIG. 6  is a simplified fragmentary perspective view of the actuator of  FIG. 5 ; 
         FIG. 7  is a sectional view of the actuator of  FIG. 2  taken through lines  7 - 7  of  FIG. 2 ; 
         FIG. 8  is an simplified perspective view of another embodiment of handle for actuating the lock of a safety door in accordance with another embodiment of the invention; 
         FIG. 9  is a simplified perspective view of another embodiment of safety door in accordance with another embodiment of the invention; 
         FIG. 10  is a simplified fragmentary view of the embodiment of  FIG. 9  showing an arrangement for unlocking a safety door from outside the door; and 
         FIG. 11  is a simplified fragmentary elevational sectional view of another embodiment of actuator in accordance with an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 1 , there is shown a simplified fragmentary elevational view of a combination  10  of a safety door  12 , a doorway frame  14 , and a building wall  16  mounted together with the door  12  being a safety door. The safety door  12  has within it a centrally located actuator  24 , a plurality of rods or bars  26 A- 26 F, three hinges  18 A- 18 C and a door knob  22 . In the embodiment of  FIG. 1 , the central actuator  24  is rotatably pinned to the door by a pin  28  ( FIG. 2 ). The rods  26 A- 26 F are in communication at one of their ends (hereinafter referred to as a first end) with the actuator  24  so that rotation of the actuator  24  in one direction (clockwise in the embodiment of  FIG. 1 ) forces the rods outwardly into the doorway frame  14  and/or floor to lock the door and rotation in the other direction (counterclockwise in the embodiment of  FIG. 1 ) withdraws the rods  26 A- 26 F from the frame  14  or floor so that the door  12  can be opened. The actuator  24  is activated in the preferred embodiment by gripping the edge  31  and moving it through an arc. However, other handles can be used as shown in the embodiment of  FIG. 7  and described hereunder. 
     When the door  12  is closed, the bars  26 A- 26 F resist the forcing of the door open. For this purpose, the bars have a thickness of at least 6 mm in their thickest dimension at an angle to their longitudinal axes, have a modulus of elasticity of at least 5,000,000 psi, and a yield point of at least 1,000 psi. In the preferred embodiment, they are solid aluminum cylindrical bars having a diameter of 12 mm but may be of many other materials and sizes. In the preferred embodiment, there are six rods although there may be between four and ten rods. With this arrangement, it is difficult to batter the door down. It can be secured from inside the building by simple rotation of the actuator  24  in one direction and can be placed in a rest condition where the door can be opened by simple rotation in the other direction of less than 90 degrees. In the preferred embodiment, the rotation is between 5 and 40 degrees. In most designs for doors, the rotation needed to insert the bars one inch into the doorway frame and a joist  58  in the floor is approximately 13 degrees and the angle increases in a manner substantially but not exactly proportionally to the distance. 
     In  FIG. 2 , there is shown a simplified, fragmentary partially sectional side view of the actuator  24 , door  12  and rods  26 A- 26 F (rods  26 A,  26 C,  26 E and  26 F only being shown in  FIG. 2 ). As shown in this view, the actuator  24  includes two flat circular parallel spaced apart end plates  30  and  32  and a handle  31 . It is mounted within a front face  10 A and a rear face  10 B of the door  12 . The handle  31  in the embodiment of  FIG. 2  is a wheel connected to the center of the end plate  30  by a pivot pin or connecting rod  28  that extends through a hole in the rear face  10 B of the door  12  for rotation with the end plates. However, the edge of an end plate could serve as the handle with access being provided to the edge through an opening in the door or the handle may have another shape such as being L-shaped. The actuator rods  26 A- 26 F are pivotally connected between the end plates  30  and  32  so that they are moved by rotation of the end plates  30  and  32 . The end plates  30  and  32  rotate between two centrally located bearing plates  46  and  48  on the inside of the front and rear faces  10 A and  10 B respectively of the door  12 . 
     The rods  26 A- 26 F (only rods  26 A,  26 C,  26 F and  26 E being shown in  FIG. 2 ) are pivotally connected to the actuator  24  by six cylindrical equally spaced apart tubular posts  34 A- 34 F (not shown in  FIG. 2  between the end plates  30  and  32 . Although, in the preferred embodiment, the actuator  24  is cylindrical, it may take any other shape that can be moved to actuate the bars  26 A- 26 F ( FIG. 1 ). In the preferred embodiment, the actuator  24  is designed to actuate six bars and for that purpose each of the equally spaced apart cylindrical tubular connecting posts  34 A- 34 F (not shown in  FIG. 2 ) fits within a corresponding one of openings  21 A- 21 F (not shown in  FIG. 2 ) in corresponding ones of right regular parallelepiped bosses  20 A- 20 F (only  20 A,  20 F and  20 E being shown in  FIG. 2 ). In the preferred embodiment, the posts  34 A- 34 F are 0.5 inches aluminum tubes, the plates  30  and  32  are 8¾ inches in diameter and the posts are set in from the periphery by ¼ inch. 
     The ease of rotating the actuator  24  is reduced by the length of the rods and the number of the rods and increased by any mechanical advantage provided. The mechanical advantage is: (1) increased by the ratio of the distance of the handle  31  from the center of rotation to the distance of the ends of the rods  26 A- 26 F from the center of rotation; (2) reduced by the sine of the angle between the rods  26 A- 26 F and the radius of the center of rotation of the posts  34 A- 34 F; and (3) increased proportionally to the diameter of the circle of rotation of the posts  34 A- 34 F. 
     In  FIG. 3 , there is shown a fragmentary, exploded perspective view of a portion of the actuator end plate  30 , a portion of the actuator end plate  32 , one of the posts  34 A, one of the rods  26 A having a corresponding boss  20 A and a machine screw  36 A. The post  34 A fits within an opening  21 A and thus holds the rod  26 A pivotally to the end plate  30 . An opening  54  in the end plate  32  is aligned with an opening  35 A in the post  34 A. The opening  35 A is tapped and a machine screw  36 A holds the end plate  32 , the boss  20 A, the post  34 A and the end plate  30  together. In the preferred embodiment, the rods are solid cylindrical 12 mm (millimeter) aluminum bars. The rods are relatively inexpensive and light in weight for easy assembly to the actuator. 
     In  FIG. 4 , there is shown a simplified perspective view of the rod  26 A, the end plate  30 , the end plate  32  and the screw  36 A showing the parts of  FIG. 3  assembled together. Thus, the rods  26 A- 26 F are pivotally bolted at locations that place the rods  26 A- 26 F within the doorway in the preferred embodiment or inside the room into which the safety door  12  opens. The machine screw  36 A has a head larger than the opening  54  ( FIG. 3 ) in the end plate  32 . Each of the rods  26 A- 26 F is connected to a corresponding one of the posts  34 A- 34 F in a similar manner. This manner of connection permits the rods  26 A- 26 F to move in a plane parallel to the doorway and outwardly within slightly elongated slots in the door and door frame. Although a specific mode of connection has been described, there are many other modes possible and known in the fastener art and the universal joint arts. 
     In  FIG. 5 , there is shown a simplified fragmentary exploded perspective view of the actuator  24  with the six rods  26 A- 26 F being adapted to be pivotally mounted between the end plates  30  and  32  with their respective central cylindrical openings  21 A- 21 F in the corresponding bosses  20 A- 20 F receiving the cylindrical posts  34 A- 34 F. With this arrangement, as the actuator  24  rotates with the pivot pin  28  in the safety door  12 , the bosses  20 A- 20 F orbit about the pivot pin  28  and rotate about the corresponding posts  34 A- 34 F over which they fit. To hold the end plates  30  and  32  together, the posts  34 A- 34 F are attached to the end plate  30  and receive their corresponding machine screws  36 A- 36 F in their tapped holes. The screw heads are outside of the actuator  24  and their shanks extending through the openings  50 A- 50 F in the end plate  32  so that the end plate  32  is held to the posts  34 A- 34 F to confine the bosses  20 A- 20 F within the actuator  24 . 
     In  FIG. 6 , there is shown a simplified perspective view of the actuator  24  showing the manner in which the actuator  24  is held together with the pivot pin  28  extending outward from the end plate  32  to rest moveably against the bearing plate  46  ( FIG. 2 ). The bearing plate  48  ( FIG. 2 ) has a central opening to permit the pivot pin to extend to the handle  31  ( FIG. 2 ) for rotation therewith. 
     In  FIG. 7 , there is shown a fragmentary elevational sectional view of the actuator  24  and door  12  taken through lines  7 - 7  of  FIG. 2  having the end plate  30 , rods  26 A- 26 F, pivot pin  28 , door  12  and slots  27 A- 27 F through which the rods  26 A- 26 F extend. The slots  27 A- 27 F are vertically elongated to permit the rods  26 A- 26 F to move both radially outwardly from the actuator  24  through the door  12  and into the door frame  14  ( FIG. 1 ) and floor joist  58  ( FIG. 1 ) and at an angle to their longitudinal axes. This is necessary because the actuator  24  moves the inner end of the rods  26 A- 26 F in an orbital curved path rather than only linearly along the direction of their longitudinal axes. 
     In  FIG. 8 , there is shown a simplified perspective view of an embodiment of handle  31 A and an end plate  30 A for an actuator in accordance with an embodiment of the invention. In the embodiment of  FIG. 8 , supporting bars  50 A- 50 D are connected to the end plate  30 A and the handle  31 A is connected to the supporting bars  50 A- 50 D. The supporting bars  50 A- 50 D meet at the center of the end plate  30 A opposite from the pivot pin. The pivot pin is welded at the opposite side of the end plate  30 A and extends perpendicularly therefrom through the opposite end plate to rest against a bearing plate in a manner similar to the embodiment of  FIG. 1 . The handle  31 A extends perpendicularly from the intersection of the supporting bars  50 A- 50 D to which it is welded through the back face of the door  12  and ends in a handle at an angle to the perpendicular to provide mechanical advantage sufficient to permit easy turning of the actuator  24  to lock the door. 
     In  FIG. 9 , there is shown a simplified perspective partly exploded away view of another embodiment of door  12 A similar to the embodiment  10  of  FIG. 1  but being adapted to be locked and unlocked from outside the door. Generally, it is preferable to utilize the embodiment of  FIG. 1  for security reasons, but under some circumstances it may be desirable to secure the door from outside against battering. For this purpose, a key  38  is provided in the form of a crank having a handle  60  for leverage. The key  38  is insertible through the front (outer) wall of the door  12 A into an actuator  24 A which is modified to receive the key  38 . With this embodiment, the rods  26 A- 26 F may be retracted or extended utilizing the key  38 . 
     As best shown in  FIG. 9 , openings  54 A- 54 F at the locations where the slots  27 A- 27 F (herein sometimes referred to as laterally extending door slots) exit the safety doors  12  and  12 A of  FIGS. 1 and 9 , are elongated in a plane parallel to the plane of the doorway. A corresponding one of the bushings  56 A- 56 F is inserted into each of the openings  54 A- 54 F. The bushings  56 A- 56 F and the openings  54 A- 54 F (herein sometimes referred to as doorway openings) in the doorway frames also have elongated slots. The elongated slots  27 A- 27 F are necessary to accommodate the motion of the rods  26 A- 26 F as the inner ends at the bosses  20 A- 20 F ( FIG. 7 ) are moved in an arcuate path by the actuator  24 . The larger the angle through which the actuator  24  rotates the larger the slots must be. The angle is affected by the diameter of the circle formed by the posts  34 A- 34 F ( FIG. 5 ) which is selected to determine the mechanical advantage obtained by rotating the larger diameter handle  31 . The distance the rods  26 A- 26 F move into and out of the doorway frame  14  ( FIG. 1 ) is determined by the angle of rotation of the actuator  24  and the diameter of the posts  34 A- 34 F ( FIG. 9 ). The bushings and slots are best illustrated at  56 D,  52 D and  54 D where the bushing  56 D is shown exploded away from the opening  54 D. 
     In  FIG. 10 , there is shown the key  38  and an embodiment  28 A of pin for the actuator  24 A ( FIG. 9 ). The pin  28 A has on its end a uniquely shaped point which is shaped to correspond to the key  38 . The key  38  has an opening  42  with a shape to match the uniquely shaped end  40  and thus permit engagement uniquely between the key  38  and the pin  28 A for turning the pin to retract or extend the bars  26 A- 26 F ( FIG. 9 ) and thus lock or unlock the door  12 A. 
     In  FIG. 11 , there is shown an elevational, fractionated sectional view, partly broken away, of another embodiment of actuator  24 B having end plates  30 B and  32 B, rods  52 A- 52 F, and a pivot pin  28 B. The end plate  32 B includes cut away portions showing the end plate  30 B. The rods include flattened ends  62 A- 62 F pivotally pinned to the end plate  30 B. With this arrangement, the handle  31 A (not shown in  FIG. 11 ) may be rotated to lock and unlock the safety door. The rods are rotatably pinned directly to the actuator plate, thus reducing the depth of the actuator. 
     In operation, the safety door  12  is secured against battering or breaking to gain entrance to a room by turning the actuator  24  in a first direction and unlocked by turning it in the opposite or second direction. Turning the actuator  24  in the first direction moves the bars  26 A- 26 F in a radially outward direction from their central location around the actuator  24  a sufficient distance so that their ends (herein sometimes referred to a second ends) extend into the doorway frame  14  far enough to prevent the door from being forcibly dislodged from the frame of the doorway. When locked, the safety door  12  resists breaking or cutting to gain entrance into a room. Turning the actuator in the second direction retracts the ends of the rods  26 A- 26 F from the doorway frame  14  and permits the door to be opened by swinging it on its hinges  18 A- 18 C such as by the door knob  22 . In this specification, the floor including the joist  58  at the bottom of the doorway is considered part of the doorway frame  14 . The bars  26 A- 26 F extend at least one inch but preferably 1½ inches or more into the doorway frame  14  at six spaced apart locations on the door and extend all the way to a common point at an actuator  24  at the center so as to perform reinforcement throughout the door. 
     To permit the easy turning of the actuator  24  by hand to lock or unlock the door  12 , the actuator  24  is pivotally pinned to the door  12  by the pin  28  ( FIG. 2 ) at a central location on the door  12 . A handle  31  ( FIG. 2 ) extends from the actuator  24  inwardly into the room far enough to be easily grasped to manually turn the actuator. In the preferred embodiment, the handle  31  is “L” shaped but may be wheel shaped as shown in  FIG. 2  or any other shape that can be easily grasped is adequate. 
     The handle is spaced at a sufficient distance from the pin  28  about which it and the rods  26 A- 26 F rotate to provide enough mechanical advantage for easy turning against the resistance to motion of the bars. The larger the number of bars and the greater the length, the greater the resistance and the larger the distance between the pin  28  and the handle  31  to which force is applied to lock or unlock the safety door  12 . The mechanical advantage is the ratio between a first distance, which is the distance between the handle  31  and the pin  28 , and a second distance which is the effective distance between the points at which the inner ends of the bars  26 A- 26 F are attached to the posts  34 A- 34 F. In the preferred embodiment, the bars  26 A- 26 F are all pivoted about points that are at the same distance from the pin  28  and so the effective distance is the actual distance. However, in this specification, the effective distance is that distance that would provide the same mechanical advantage if the distances were all the same and the resistance to motion provided by each bar is the same. If the resistance provided by each bar is the same, the effective distance is generally the average distance. 
     In the preferred embodiment, the actuator  24  is rotated through 15 degrees in a first direction to lock the door and 15 degrees in the opposite direction to unlock the door. However, it may be designed for different amounts of rotation depending on the distance into the doorway frame the rods  26 A- 26 F are to extend and the diameter of the rotary member. In one embodiment, the door is only locked and unlocked from inside. However, in other embodiments, a key  38  with a hollow specific shape on its outer end may be inserted through the door into a special pin  28 A with a correspondingly shaped end so as to move the actuator  24  from outside the door. The pin is fastened to the plates  30  and  32  for movement therewith. 
     Although a preferred embodiment of the invention has been described with some particularity, many modifications and variations in the invention are possible in the light of the above teachings. Therefore, it is to be understood, that, within the scope of the appended claims, the invention may be practiced other than as specifically described.