Patent Publication Number: US-6705652-B2

Title: Security system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     This invention pertains to security systems. 
     More particularly, the invention pertains to a system for securing a door used to access a room. 
     In a further respect, the invention pertains to a security system that spans a door to a room and permits the door to be opened to a slightly ajar position to engage the security system without permitting the door to be opened an amount sufficient to see into or out of the room. 
     (2) Description of related Art including information disclosed under 37 CFR 1.97 and 1.98. 
     A variety of systems for securing a door are known in the art. U.S. Pat. No. 4,974,889 describes a fixed length cable that spans a door. The ends of the cable are secured on either side of the door such that the cable prevents the door from being opened. The cable is provided with sufficient slack to permit the door to be opened so the occupant of a room can view the person at the door. 
     U.S. Pat. No. 5,282,656 to Fizer discloses a telescoping door bar that spans a door. The ends of the telescoping bar are secured on either side of the door such that the telescoping bar prevents the door from being opened. The door can be opened far enough, however, or “cracked” so that a person can look between the door and the door jamb. 
     U.S. Pat. No. 4,429,911 to O&#39;Neal et al. discloses a door bar that spans a door. The ends of the bar are secured on either side of the door such that the telescoping bar prevents the door from being opened. The door can be opened far enough, however, or “cracked” so that a person can look between the door and the door jamb. 
     U.S. Pat. No. 4,067,598 to Mansour discloses a door bar that spans a door. The ends of the bar are secured on either side of the door such that the bar prevents the door from being opened. A spacer clip 70 is positioned intermediate the door and the bar to prevent the door from being opened. 
     U.S. Pat. No. 4,601,503 to Wicks, Sr. discloses a door bar that spans a door. The ends of the bar are secured on either side of the door such that the bar prevents the door from being opened. 
     One apparent disadvantage of the prior art security systems described above is that they appear to allow, unless a spacer is interposed between a bar and the door in the manner shown in the Mansour patent (U.S. Pat. No. 4,067,598), the door to be opened an amount sufficient for the individual opening the door to see into the room. If the individual can see into the room, he can determine visually the location of the security bar on the door and can attempt to cut or break the bar. 
     Another disadvantage of existing security systems is that they sometimes anchor supports into the molding and/or door jamb. Molding typically is not structurally strong, nor are door jambs. 
     A further disadvantage of existing security systems is that when a bar is secured to either side of the molding, the bar is spaced away from the molding, increasing the distance a door can be opened before the door contacts the molding. 
     Another disadvantage of existing security systems is that while the systems block or prevent movement of a door when the door is opened, the systems do not appear to develop a positive counteracting force that tends to push a door closed. 
     Accordingly, it would be highly desirable to provide a door security system which would prevent a door from being cracked without requiring the use of a spacer of the type disclosed in U.S. Pat. No. 4,067,598, which would not require that a bar be anchored in the door jamb or molding, and which would generate a positive counteracting force that would act to force a door back to a closed position. 
     Therefore, it is a principal object of the invention to provide an improved security system for a door. 
     Another object of the invention is to provide an improved door security system of the type including a bar that spans a door and is affixed at either end to prevent the door from being opened. 
     A further object of the invention is to provide an improved door security bar system of the type described which generates a force acting to close the door. 
     Still another object of the invention is to provide an improved door security bar system of the type described which prevents a person attempting to gain entry into a room from being able to see past a door into the room when the person attempts to force the door open. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
     These and other, further and more specific objects and advantages of the invention will be apparent to those skilled in the art from the following detailed description thereof, taken in conjunction with the drawings, in which: 
     FIG. 1 is perspective view illustrating the novel metal sleeve—cable construction utilized in the invention; 
     FIG. 2 is a perspective view illustrating the door security system of the invention; 
     FIG. 3 is a section view further illustrating details of the construction of FIG.  1  and taken along section lines  3 — 3  thereof; 
     FIG. 4 is a section view further illustrating the door security system of FIG.  2  and mode of operation thereof and taken along section lines  4 — 4  thereof; 
     FIG. 5 is a force vector diagram illustrating the forces generated by a door on the metal sleeve—cable construction; and, FIG. 6 is a force vector diagram illustrating the force generated by the metal sleeve-cable construction on a door to displace the door back toward the closed position. 
    
    
     BRIEF SUMMARY OF THE INVENTION 
     Briefly, in accordance with the invention, I provide an improved security system. The security system includes apparatus defining a door opening for a room. The apparatus includes at least a pair of vertically oriented spaced apart support members, a door jamb intermediate the support members, and a pair of vertically oriented molding members each adjacent and extending outwardly from the door jamb. The security system also includes a door coupled to the door jamb for opening and closing the opening; a hollow substantially rigid flexible metal rod spanning the door opening and having a pair of opposing ends; at least one cable extending into the metal rod; and, two fixing members each secured to a different one of the support members. The cable and rod are securable at each end of the rod to one of the fixing members such that the rod contacts each of said molding members so that the door can be moved from a closed position to a slightly ajar position in which the door engages and flexes the bar without permitting a person at the door to view through the opening the room and the rod. The flexed bar generates a force against the door acting to displace the door to the closed position. 
     In another embodiment of the invention, I provide an improved method for securing a doorway to a room. The doorway includes a door opening for the room. The door opening includes at least a pair of vertically oriented spaced apart support members; a door jamb intermediate the support members; a pair of vertically oriented molding members each adjacent and extending outwardly from the doorjamb; and, a door coupled to the door jamb for opening and closing the opening. The method includes the steps of providing a security system including a hollow substantially rigid flexible metal rod spanning the door opening and having a pair of opposing ends; at least one cable extending into said metal rod; and, two fixing members. The cable and rod being securable at each end of the rod to one of the fixing members. The method also includes the steps of installing one of the fixing members adjacent one of the molding members and extending into one of the support members; installing the other of the fixing members adjacent the other of the molding members and extending into the other of the support members; and, securing each end of the rod to a different one of the fixing members such that the rod contacts each of the molding members so that the door can be moved from a closed position to a slightly ajar position in which the door engages and flexes the bar without permitting a person at the door to view through the opening the room and the rod. The flexed bar generates a force against the door acting to displace the door to the closed position. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to the drawings, which depict the presently preferred embodiments of the invention for the purpose of illustrating the practice thereof and not by way of limitation of the scope of the invention, and in which like reference characters refer to corresponding elements throughout the several views, FIG. 1 illustrates a security bar used in the security system of the invention and generally indicated by reference character  10 . Bar  10  includes a hollow substantially rigid flexible rod  12 . While the material utilized to fabricate rod  12  can vary, metal is presently preferred. Rod  12  presently consists of extruded aluminum. A pliable cable  11  extends into rod  12 . The construction of cable  11  can vary as desired. Cable  11  presently consists of {fraction (3/16)} inch diameter 7×19 aircraft cable. Cable  11 , while pliable, has little elasticity and can not flex. 
     As used herein, a material has the ability to flex if the material, when bent or compressed, elastically attempts to return to its normal configuration. If the ends of a straight substantially rigid elastic rubber rod are held and the ends of the rod are displaced such that the rod takes on a curved or bowed shape, forces are developed which act to return the rod to its normal straight configuration. Consequently, the rubber rod is elastic and can be flexed. One advantage of the invention is that it combines in a security bar  10  a length of substantially rigid flexible metal rod with a length of strong pliable cable. Regardless of whether the cable is flexible (and the presently preferred cable does not have any significant flexibility) the combination of the cable and metal rod produces an unusually strong, but flexible, structural member that not only resists shear forces but also, as will be described below, generates a force F 4  that acts to return a door to a closed position. 
     The width, indicated by arrows A in FIG. 5, of the wall of rod  12  can vary as desired, but is presently {fraction (3/16)} inch and is preferably in the range of about {fraction (1/16)} inch to ½ inch. 
     Cable  11  is threaded through adjacent cylindrical openings  40  and  41  formed in rod  12 . Openings  40  and  41  have a diameter that is about 0.0005 to 0.005 inch greater than the outside diameter of cable  11  so that cable  11  slides snugly into openings  40  and  41 . A single length of cable  11  is presently preferred, with each end  14 ,  15  of the cable inserted in opening  41  in the manner shown in FIG. 1 to form loops  16 ,  17 . Each loop is at one end  42 ,  43  of rod  12 . The intermediate portion  13  of cable  11  extends through opening  40  of rod  12 . 
     Cable  11  is doubled over on itself both to form loops  16  and  17  and to insure that a pair of parallel lengths  13  and  15  of cable each extend through one of openings  40  and  41  adjacent the point  28  at which a door edge  22  will bear against bar  10 . Cable lengths  13  and  15  significantly increase the strength of bar  12 , especially when bar  12  is oriented in the manner shown in FIG. 4 with the parallel cable lengths  13  and  15  not stacked one on top of the other lying in a vertically oriented plane, but instead oriented side-by-side lying in a generally horizontally oriented plane. In the configuration illustration in FIG. 4, cable length  13  is closer to edge  22  than cable length  15 . 
     A first length of cable can be used to make loop  16 . A second length of cable can be used to make loop  17 , where the first and second lengths of cable are not attached to one another, but are separate from one another. Or, a length of cable can be utilized that extends only through opening  40  (or  41 ), so there is not any cable in opening  41  (or  40 ). The number of pieces of cable used to fabricate bar  10  and the length of each piece of cable can vary as desired. A clip of other fastening means can be secured to the end of rod  12  or to the ends of cable  11  and used to fasten bar  10  to hook  19 ,  20  instead of using loops  16  and  17 . Fastening means other than hooks  19  and  20  and loops  16  and  17  can be utilized to secure bar  10  in place adjacent a door  21 . 
     Hooks  19 ,  20  presently include externally threaded wood screw ends that are turned into a king stud  36 ,  38  or jack stud  37 ,  39 . As noted, any desired fastening means other than hooks  19 ,  20  can be utilized to secure the ends of bar  10  in place. Hooks  19 ,  20  are positioned to receive loops  16  and  17  in the manner illustrated in FIGS. 2 and 4 such that bar  10  is adjacent or preferably bears against and contacts molding members  23  and  24 . 
     As shown in FIGS. 2 and 4, the door opening includes vertically oriented jack studs  39  and  37 , vertically oriented king studs  36  and  38 , vertically oriented molding strips  23  and  24 , a doorjamb mounted intermediate king studs  36  and  38  and including vertically oriented members  30  and  31 , and sheet rock or other wall panels, boards, coverings, etc.  44 ,  45 ,  46 ,  47 . Door  21  is hung on hinges  25  in the door opening on member  30 . Door  21  includes front rectangular surface  38  and rear rectangular surface  39 . Surface  38  is parallel to surface  39 . 
     Door  21  includes front vertically oriented edge  22  and back vertically oriented edge  33 . Edges  22  and  33  are parallel. 
     As illustrated in FIG. 4, when the security bar  10  is installed with loops  16  and  17  secured to hooks  19  and  20 , bar  10  preferably rests against a portion of each of molding strips or members  23  and  24 . Member  23  includes vertically oriented edge  35 . 
     When door  21  is opened in the direction of arrow B, edge  22  contacts bar  10  at point  28 . If a force F 1  of at least about ten pounds per square inch is applied to door  21  when edge  22  contacts bar  10 , then bar  10  bows, or flexes, in the manner indicated by ghost outline  10 A. When bar  10  flexes, a force F 4  is generated by bar  10  against edge  22  of door  21  as bar  10  attempts to elastically return to its normal linear configuration illustrated in FIG.  1  and indicated in FIG. 4 by reference character  10 . While the force F 1  that needs to be applied to point  28  on bar  10  by edge  22  to cause bar  10  to flex can vary as desired, it is presently preferred that the force be at least ten pounds per square inch. The flexing of bar  10  to produce force F 4  is important in the practice of the invention because force F 4  actively opposes an individual attempting to force door open  21  in the direction of arrow B. In contrast, if bar  10  is perfectly rigid and does not flex, bar  10  prevents door  21  from opening but does not generate a force that functions to close door  21  in a direction opposite the direction indicated by arrow B. 
     When door  21  is pressed against bar  10  in the direction of arrow B, a force F 1  is generated. F 1  includes a component F 2  acting in a direction generally parallel to bar  10  and a component F 3  acting in a direction generally perpendicular to bar  10 . When the magnitude of component F 3  is great enough, bar  10  flexes, or bows, in the manner indicated by dashed lines  10 A. The magnitude of F 3  necessary to flex bar  10  can vary in accordance with the construction of bar  10  but presently the force F 3  necessary to flex bar  10  is at least ten pounds per square inch. 
     In the practice of the invention, hooks  19  and  20  are installed so that bar  10  is, when mounted on hooks  19  and  20 , positioned in contact with, or sufficiently near, molding members  23  and  24  to prevent door  21  from opening far enough in the direction of arrow B to enable an individual to view  32  between edge  33  and edge  35  into room  50 . Preventing an individual from being able to see between edge  33  and edge  35  also prevents an individual from visually identifying the location at which bar  10  spans the distance from edge  22  to molding piece  23 , which makes it more difficult for the individual to cut or otherwise disable bar  10  and gain entry into room  50 .