Patent Publication Number: US-2007120012-A1

Title: Safe escape lock

Description:
TECHNICAL FIELD OF THE INVENTION  
      The present invention relates generally to watertight and airtight doors. More particularly, the present invention relates to locking mechanisms for such doors.  
     BACKGROUND OF THE INVENTION  
      A compartment, such as a sea vessel enclosure, has its opening closed in a watertight manner by a door panel hingedly mounted on the enclosure wall adjacent to the opening to form an opening closure door pivotally displaced to a closure position. Watertight doors are well known in the art. Such doors commonly are used to prevent water infiltration from one compartment of a ship to another or from one area of a building to another. Such doors also can be used to prevent infiltration of air or other gas or vapor from one volume to another. A watertight door assembly typically comprises a door; a door frame; a hinge mechanism for pivoting the door about the door frame; a resilient, compressible seal for affecting a watertight seal between the door and the door frame; and a sealing mechanism.  
      Sealing mechanisms used in shipboard marine applications must withstand extremely corrosive environments while maintaining watertight mechanical seals. In applications such as weatherproof deck doors, windows, hatches, and scuttles, watertight door sealing mechanisms (also known as dog latches) must provide a strong mechanical seal, must be operational through a wide range of temperature extremes, and must prevent the passage of water and air in heating ventilation and cooling systems.  
      Doors and hatches used in ships and analogous vessels often utilize quick-acting sealing mechanisms that allow the door or hatch to be sealed and unsealed by rotating a single handle. In many cases, the handle actuates a series of rack and pinion gears, ratchet gears, or levers, which in turn simultaneously actuate a series of dogs located around the periphery of the door. The dogs engage cam surfaces on the door frame or coaming, and pull the door against the frame to form a watertight seal between the door and the frame when the door is closed and sealed. Such sealing mechanisms are advantageous because they allow the door or hatch to be secured and sealed very rapidly.  
      In addition to being easily secured and sealed, a sealing mechanism for a watertight door must operate quickly to permit rapid opening and closing during a fire or other emergency situation. The just-described sealing mechanism is not easily and rapidly openable. This is especially true if the door is to be opened from the inside of the compartment. If a door cannot be quickly opened from the inside of a compartment, there may be a danger that personnel may be trapped in a compartment.  
      Coast Guard regulations require watertight doors to be locked to prevent unauthorized access to the compartment associated with the door. However, in the event of an emergency, personnel in the compartment should be able to exit the compartment in a rapid and orderly manner. Therefore, any lock used on such doors should be capable of being removed in a rapid and orderly manner under emergency conditions.  
     SUMMARY OF THE INVENTION  
      The above-discussed disadvantages of the prior art are overcome by a locking mechanism for a watertight door that has a threaded shaft on one side of a mounting plate and an eye element on the other side of the mounting plate. A locking chain is securely attached to the eye element to lock the door in position by means of a hasp mechanism on the door. The mounting plate is fixed to a bulkhead associated with the door and the threaded shaft extends through a bore defined through the bulkhead associated with the door into the interior of the compartment being closed by the door. A threadable nut, such as a wing nut, is threadably mounted on the threaded shaft to secure the mounting plate to the bulkhead associated with the door. In the event of an emergency, the threaded nut can be removed from the threaded shaft and the mounting plate will then be freed of the bulkhead associated with the door and can be removed from the door bulkhead. The door will then be freed from the bulkhead and openable from within the compartment.  
      Using the watertight door locking mechanism embodying the present invention will permit personnel who may otherwise be locked inside a compartment to free themselves from the compartment by removing the door locking mechanism from the bulkhead associated with the door to free the door even though the personnel are located inside the compartment and the lock on the door remains in place on the door. Freeing a watertight door in an emergency situation from inside a compartment is thus quick and easy.  
      Other systems, methods, features, and advantages of the invention will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the invention, and be protected by the following claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES  
      The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views.  
       FIG. 1  is a perspective view of a watertight door locking mechanism embodying the present invention.  
       FIG. 2  is a side elevational view taken along line  2 - 2  of the watertight door locking mechanism shown in  FIG. 1 .  
       FIG. 3  is a schematic showing the lock mechanism mounted in place on a watertight door and on a bulkhead associated with the door. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to the figures, it can be understood that the present invention is embodied in a watertight door locking mechanism  10  which permits personnel located inside a compartment of a ship to easily and quickly open a door that may be locked on the outside of the door.  
      Mechanism  10  comprises a watertight door  12  for use on a compartment of a vessel. Watertight door  12  has a bulkhead  14  associated with the door. Bulkhead  14  has a bore  16  defined therethrough with the bore being in communication with an interior of the compartment.  
      A mounting plate  20  has a first surface  22  which is located adjacent to bulkhead  14  when the mounting plate is in place on the bulkhead and a second surface  24  which is interposed between first surface  22  and bulkhead  14  when the mounting plate is in place on bulkhead  14 .  
      A sealing element  26  is mounted on second surface  24  of the mounting plate to be interposed between second surface  24  of the mounting plate and bulkhead  14  when the mounting plate is in place on the bulkhead. Sealing element  26  ensures that water or other fluids will not bypass door  12  in an undesirable manner.  
      An eye element  30  is securely mounted on first surface  22  of the mounting plate to be one piece with the mounting plate.  
      A locking chain  34  is securely fixed at one end  36  thereof to eye element  30 . A second end  38  of chain  34  is adapted to be locked to a locking unit  40  on door  12 . A padlock  44 , or the like, can be used to affect the locking function between chain  34  and door  12 .  
      When chain  34  is locked to locking unit  40  and to mounting plate  20 , door  12  is locked against unauthorized entry into a compartment associated with door  12 . The door is opened in the normal manner from outside the compartment by unlocking padlock  44  and removing chain  30  from locking unit  40  to free the door from the bulkhead.  
      A threaded post  50  has a first end  52  which is unitary and one-piece with second surface  24  of mounting plate  20  and a second end  54  which is spaced apart from first end  52 . Threaded post  50  is accommodated in bore  16  defined through bulkhead  14  associated with the door when mounting plate  20  is in place on the bulkhead. The one piece construction of plate  20  and post  50  ensures that the plate and post will be strong and not easily defeated.  
      A threaded nut  60  is threadably mounted on threaded post  50  and is located in the interior volume of the compartment when threadably engaged with the threaded post when mounting plate  20  is in place on the bulkhead associated with door  12  to hold the mounting plate in place on bulkhead  14 . Mounting plate  20  will be freed of bulkhead  14  when threaded nut  60  is removed from threaded post  50  whereby mounting plate  20  can be removed from bulkhead  14  after threaded nut  60  is removed from threaded post  50 .  
      Use of mechanism  10  can be understood from the teaching of the foregoing disclosure and thus will not be presented in detail. A door is locked closed by attaching chain  34  to lock  40  on the door and placing an appropriate lock on lock  40 . The other end of chain  34  is securely attached to eye element  30  which is securely fixed to bulkhead  14  via mounting plate  20 . Mounting plate  20  is located with respect to door  12  whereby access to threaded nut  60  is not possible when chain  34  is locked to the door. The door is thus locked against unauthorized entry. However, in the event personnel inside the compartment associated with door  12  must exit that compartment via door  12 , even when the door is locked on the outside by means of chain  34 , such exit can be made by removing threaded nut  60  from threaded post  50  thereby freeing post  50  and mounting plate  20  associated therewith from bulkhead  14 . Once mounting plate  20  is free of the bulkhead, the lock effected between the mounting plate and the door is free of the bulkhead, and the door can be opened from the inside even if lock  44  remains in place.  
      While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of this invention. For instance, the mounting plate can be attached to the outer surface of the door  12  and the threaded nut  60  can be coupled to the thread post  50  on the inner surface of the door  12 . Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.