Abstract:
The security system has a control. The control is attached to an actuator for emergency crash landing purposes and a manual controller. The controller is attached to a plurality of tethers, each having a fork at its terminal end. The fork is attached to several types of security devices. When the control is actuated, tension on the tethers causes the forks to become dislodged from the mechanisms to which they attach. Once dislodged, the mechanism are disabled, allowing easy access through the cockpit door. In this manner, security of the cockpit is insured, yet will not inhibit the crew&#39;s safety in the event of an emergency.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention relates to a security system for aircraft doors.  
         BACKGROUND OF THE INVENTION  
         [0002]    There is always a need to secure the cockpit of an aircraft. The security system must allow easy access to authorized personnel, yet prevent all other access. Also, the system must allow quick exit by the cockpit crew in the event of a crash landing.  
           [0003]    Currently cockpit doors are not designed to be structurally sound. They are relatively thin and flexible, making them susceptible to forced entry. The doors are provided with conventional locks, including bolts entering the bulkhead at the end of a door, opposite the hinges. The hinges are of conventional structure, attaching the cockpit door to the bulkhead. While the conventional locking mechanism provides security to the cockpit door, they present a hindrance to the quick exit from the cockpit by the crew in the event of an emergency landing.  
           [0004]    The prior art discloses several types of bolts to secure a door. U.S. Pat. No. 4,379,577 (Robertson) discloses a latch bolt strike lock. The slidable bolt has a recess  62 . The bolt enters the door frame DF and is retained by a locking plate  40  having a tab  44  that fits into the recess. The locking plate is perpendicular to the sliding bolt.  
           [0005]    U.S. Pat. No. 3,591,219 (Graziosi) discloses a safety door lock having a swinging arm  12  with an aperture  42 . Locking bolts  56  have cylindrical section  60  spring biased through the aperture  42 . U.S. Pat. No. 4,746,152 (Wilcox) discloses a door lock having a sliding bolt  32  with an aperture  40 . A locking pin is spring biased through the aperture  40  to retain the sliding bolt in a locked position.  
         SUMMARY OF THE INVENTION  
         [0006]    The security system has a controller. The controller is attached to an actuator for emergency crash landing purposes and a manual override. A plurality of tethers, each having a fork at its terminal end, are attached to the controller. The forks are attached to several types of security devices. When the controller is actuated, tension is created on the tethers to cause the forks to become dislodged from the mechanisms to which they attach. Once dislodged, the mechanism are disabled, allowing easy access through the cockpit door. In this manner, security of the cockpit is insured, yet will not inhibit the crew&#39;s safety in the event of an emergency.  
           [0007]    A cockpit security device comprises a bulkhead having an entrance with a door closing said entrance. A pair of supports on the door slidably retain a bolt by said pair of supports. A rod rigidly connects to and extends between the pair of supports. A bracket rigidly connects to said bolt, the rod passing through the bracket. A stop is on said rod and a spring extends between one of the supports and the stop. A spring restrained from moving by the stop. The spring is able to move the stop and apply force against the bracket to disengage the bolt from said bulkhead.  
           [0008]    A cockpit security system comprises a motion sensing device and a plurality of tethers extending from the motion sensing device, each tether terminating in a fork. The forks are attachable to security devices.  
           [0009]    A cockpit security comprises a door for closing an entrance in a bulkhead and a hinge attached to the door to allow rotational motion of said door. The hinge comprises a knuckle having a diameter and a housing extends from the knuckle. The housing has a width smaller than said knuckle diameter. A pin retained in the knuckle has a reduced neck portion. The reduced neck portion has a width smaller than the housing width and a depth greater than the housing width. The pin is moved from the knuckle into the housing when the door is closed and a force is applied to the door.  
           [0010]    A cockpit security device comprises a bulkhead having an entrance and a door closing the entrance. A hinge attached to the door and the bulkhead allows rotational motion of the door. The hinge comprises a pair of cups, one of said cups located above the door and the other of the cups located below the door.  
           [0011]    A mounting housing is retained within each of said cups and a wire is retained by and extends between said mounting housings. A guide on said door retained the wire to attach the wire to the door so that the door pivots about the wire. The mounting housing are releasable from the cups.  
           [0012]    A hinge attached to the door to allow rotational motion of said door. The hinge comprises a knuckle having a diameter and a housing extends from the knuckle. The housing has a width smaller than said knuckle diameter. A pin retained in the knuckle has a reduced neck portion. The reduced neck portion has a width smaller than the housing width and a depth greater than the housing width. The pin is moved from the knuckle into the housing when the door is closed and a force is applied to the door.  
           [0013]    A cockpit security device comprises a bulkhead having an entrance and a cockpit door closing the entrance. A bolt is slidable mounted on the door. A guide tube in the bulkhead houses a spring within the guide tube. The spring is biased against the bolt. The guide tube allows for limited motion of the door in response to a force applied to the door. The spring returns the door to its original position upon removal of the force.  
           [0014]    A cockpit security device comprises a bulkhead having an entrance and a cockpit door closing said entrance. At least one connection between the bulkhead and the cockpit door retains the door in a closed position. There are means for removing the at least one connection to allow for the door to fall from the entrance.  
           [0015]    It is an object of the invention to provide a security system for aircraft doors.  
           [0016]    It is another object of the invention to provide a security system which disables the safety mechanisms in the event of an emergency landing.  
           [0017]    It is another object of the invention to provide a security system preventing unauthorized access to the cockpit.  
           [0018]    It is yet another object of the invention to provide a security system which utilizes several mechanisms for providing security.  
           [0019]    It is still another object of the invention to provide a security system that is easy to install and retrofit existing aircraft.  
           [0020]    These and other objects of the invention will become apparent to one of ordinary skill in the art after reviewing the disclosure of the invention.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]    [0021]FIG. 1 is a view of the control for the security system;  
         [0022]    [0022]FIG. 1A is a detailed view of the end of the controller;  
         [0023]    [0023]FIG. 2 is a view of the actuator for the controller;  
         [0024]    [0024]FIG. 3 is a view of the bolt for securing the cockpit door;  
         [0025]    [0025]FIG. 4 is a top view of the bolt for the cockpit door with the securing device;  
         [0026]    [0026]FIG. 5 is a side view of the bolt for the cockpit door;  
         [0027]    [0027]FIG. 6 is a view of a hinge wire for the cockpit door;  
         [0028]    [0028]FIG. 7 is a detailed view of the housing for the wire hinge;  
         [0029]    [0029]FIG. 8 is a cross-sectional top view of a hinge knuckle for a cockpit door;  
         [0030]    [0030]FIG. 9A is a side view of the hinge pin for the cockpit door; and  
         [0031]    [0031]FIG. 9B is a front view of the hinge for the cockpit door.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0032]    The invention prevents unauthorized entry into the cockpit of an aircraft. The combination of the bolt lock and hinge of the invention allows the cockpit door to linearly move a short distance under the application of force. When the force is removed, the door returns to its original position under the force of springs. The invention also provides for the removal of all connections between the cockpit door and bulkhead to allow for the quick exit of the flight crew under emergency conditions. A motion detector governs the removal of the connections.  
         [0033]    [0033]FIG. 1 shows the controller for the security system. The controller has a block  12  retained for reciprocal motion within sliders  14 . The block is retained in a right-most position by the bias of a spring  16 .  
         [0034]    A plurality of tethers  20  extend from the right side of the block. Each tether is attached to a fork  22 . The purpose and function of the fork is described hereinafter. The block  12  can be moved to the left by one of two mechanism. A lanyard  18  extends from the left side of the block and can be manually grasped and pulled to move the block to the left. Also, a tether  20  extends to an actuator  30 . The function and structure of the tether is described later. When a force is applied by either the lanyard or by the actuator, the bias of the spring  16  is overcome and the block moves to the left. The movement of the block creates tension on the tethers  20  to dislodge the fork  22 .  
         [0035]    The connection of the tethers to the block  12  is shown in FIG. 1A. The block  12  has a series of recesses into which plungers  26  are threadedly received. The plunger  26  has a central passage through which a tether passes. The tether  20  terminates in a bead  24  retained at the bottom of the plunger  26 . When the plunger  26  is threadedly engaged with the recess of the block  12 , the tethers  20  are secured. A lock nut  28  attached to the body of the plunger  26  inhibits the movement of the plunger  26  over time.  
         [0036]    The structure of the actuator  30  is clearly seen in FIG. 2. The actuator  30  has a housing  32  into which a tether  20  extends. A bead  24  is suspended between supports  34  and an arm  36 . The arm  36  is pivotally attached to the side of the housing  32 . Under forces exerted by such action as a emergency landing, the bead  34  will be displaced from its equilibrium position due to the movement of the arm  36 . The bead  26  will drop and apply tension to the tether  20 . This tension causes the block  12  to move to the left.  
         [0037]    A top view of a cockpit door and bulkhead is seen in FIG. 3. In the view, the door  50  is provided with ballistic resistant material  56 . On the inside of the door, a pair of supports  54  support a bolt  52 . The bolt  52  is free for reciprocal motion within the supports  54 . The end of the bolt  52  extends into bulkhead  40 . The bolt  52  extends through a slot in the edge of the bulkhead  40 . The bulkhead  40  has a guide tube  42  housing a spring  44 . The spring  44  terminates in a strike plate  46 . The spring biases the strike plate against the bolt  52 . If force is applied against the outside of the door, the door will move into the cockpit compressing the spring  44  until the bolt  52  reaches the end of the slot. In this manner, the door  50  will move a small distance in reaction to an external force. However, the travel distance of the door is limited by the bolts traveling within the slot.  
         [0038]    [0038]FIG. 4 shows a security system for the door bolt. The bolt  52  is provided with a handle  57  for the manual retraction of the bolt  52  from the bulkhead. A rod  60  is rigidly attached and extends between the two supports  54 . The rod  60  has a collar  62  and a notch  64 . The collar  62  freely moves along the bolt  52 . The notch  64  retains a fork  22 . When the fork is in place, the collar  62  is impeded from movement. A spring  66  extends between a support  54  and the collar  62 . When the fork is removed by increased tension in its tether  20  as described earlier, the spring extends and pushes the collar until it reaches bracket  68  rigidly attached to the bolt  52 . When the collar  62  reaches the bracket  68 , force provided by the spring  66  pushes the bracket  68 , and therefore pushes the bolt  52 , to retract the bolt from the bulkhead. The side view of the bolt, supports and rod, are seen in FIG. 5.  
         [0039]    Turning now to FIG. 6, a hinge mechanism for a cockpit door is illustrated. The system uses a pair of housings  70  located in the floor and bulkhead of the cockpit. A wire  80  extends between the upper and lower housings  70 . The door has at least one guide through which the wire  80  passes so that the door is able to pivot about the wire which acts as a hinge. The guide consists of a bolt  82  through which the wire  80  passes. The bolt is retained to the door by supports  83 . A bead  24  allows tension to be applied to the bolt  82 .  
         [0040]    The detail of the upper and lower housing is seen with reference to FIG. 7. The housing has a cup  72  provided with a central aperture  73 . A mounting housing  74  is received within the cup  72 . A stem  75  on the mounting housing extends through the central aperture  73  of the cup  72 . A plunger  76  is retained within the mounting housing  74 . A spring  77  provides tension on the plunger to bias it in the direction of the stem  75 . The plunger retains the wire  80  terminating in a bead  24 . A set screw  78  within the body of the plunger prevents rotation of the wire  80 .  
         [0041]    The stem  73  is provided with notches. A fork engages the notches and retains the mounting housing in its position relative to the cup  72 . In the event of an emergency landing that causes tension on the tethers  20  to dislodge the fork  22 , the assembly of the mounting housing  74  and plunger  76  separate from the cup. All tension on the wire  80  will thereby be lost and the cockpit door would no longer be provided any support from the wire  80 . This allows the cockpit crew to easily move the cockpit door from the access opening. If the door is provided with a series of bolts  52  as described earlier, no support at all will be provided to the door and it will simply fall to the floor and out of the way of the cockpit crew wishing to leave the cockpit.  
         [0042]    A second type of hinge that can be used on the cockpit door is shown in FIG. 8. FIG. 8 is a cross-sectional top view of knuckle  84  having a housing with smaller dimensions than the knuckle  84  extending from the knuckle  84 . In use, the housing would be perpendicular to the door. Within the housing is a spring  88  whose function will be described hereinafter. Brackets  89  extend from the knuckle for attaching the hinge to the bulkhead and the cockpit door.  
         [0043]    The hinge pin  90  useable with the knuckle of FIG. 8 is shown in FIG. 9A. FIG. 9A shows the side view as is seen at the pin  90  has a head  92 , a top section  94  having a square cross-section, a middle neck portion having a width smaller than the top section and slightly smaller than the width of the housing  86 . Bottom section  98  has a round cross-section.  
         [0044]    The side view of the pin is seen in FIG. 9B. In this view, it is seen that the middle neck portion  96  has a depth equal to both the top square section  94  and bottom round section  98 . The import of this is that when the door is in the closed position, the width of the middle neck portion is aligned with the housing  86 . When in the open position, the pin is rotated so that the depth of the middle neck portion  96  prevents the entry of the pin into the housing  86 . In the event that a force is applied to the exterior of the cockpit door when closed and the bolt  52  travels within the slot, as previously described, the edge of the door opposite the bolt  52  with the hinge will also be able to travel a lateral distance into the cockpit. The spring  88  in the housing  86  returns the pin to its original position within the knuckle  84 .  
         [0045]    The various systems useable with the forks  22  actuated by the controller  10  previously described result in a security system for preventing unauthorized access to a cockpit, but allowing the quick exit of the cockpit crew in the event of an emergency landing. The various components can be used alone or in combination as the user desires.  
         [0046]    While the invention has been described with reference to preferred embodiments, variations and modifications would be apparent to one of ordinary skill in the art without departing from the scope of the invention. Consequently, the invention is not to be limited to the exact embodiments but encompasses these variations and modifications and by the appended claims.