Abstract:
Embodiments of the present invention relate generally to door locking systems for use in connection with trash compactor systems for preventing inadvertent opening of the main door during a compaction cycle.

Description:
This application claims the benefit of U.S. Provisional Application Ser. No. 61/343,262, filed Apr. 26, 2010 titled “InFlight Trash Compactor Main Door Interlock,” the entire contents of which are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     Embodiments of the present invention relate generally to door locking systems for use in connection with trash compactor systems for preventing inadvertent opening of the main door during a compaction cycle. 
     BACKGROUND 
     Collecting and disposing of trash in confined conditions, particularly on-board passenger transport vehicles, such as aircraft, trains, ships, buses, RVs, and other water or air travel vessels can be challenging. However, a good deal of rubbish is generated on such vehicles. For example, after in-flight beverage service, unused items are collected, which often includes drink cups, napkins, newspapers, food wrappers, tea bags, beverage cans, other packaging or non-consumable items and the like, food wastes, or any other type of disposable item that a passenger may consume or bring on-board. 
     Trash compactors are thus often used in aircraft and other vehicle galleys in order to manage the amounts of trash generated. If the main door of the trash compactor is opened during a compaction cycle, there are built-in safety sensors on the main door that deactivate the downward movement of the platen (the plunger-like plate that raises and lowers in order to compress the trash in the compactor unit) to prevent harm to the user. Although this deactivation addresses a definite safety need, it fails to address the nuisance that occurs when the main door is opened before the trash container in the unit is full. 
     Because compaction applies a substantial load on the contents of the trash container in the compactor unit, the sides of the container exert a continuous force against the main door and walls of the compactor unit. This force causes the container to expand, press, or bulge outwardly against the door and walls—this is normally not of concern because the container is supported and contained by all sides of the compactor unit. However, if the main door is prematurely opened during the compaction cycle when the platen is applying pressure or force to the container contents, it causes the container to bulge out the front door opening. The container can also bulge out if the main door is opened at any time between one of the compaction cycles, but before the container is entirely full and ready to be removed from the unit. Once the container bulges out, it is difficult (if not impossible) to re-close the front door in order for the compression/compaction cycle to continue. Consequently, no more trash can be loaded, and no more compaction cycles can take place. The partially full box must be removed and replaced with an empty box. If the platen gets jammed where it can&#39;t be retracted, the attendant usually has to rip the trash container apart, empty its contents on the floor, position a new container in the compactor unit, re-load the trash into the new container, and being the compaction cycle again. This is a messy and time-consuming process. 
     Accordingly, it is desirable to provide a mechanism that prevents the main door of a trash compactor from being opened any time that a compaction cycle is taking place. 
     BRIEF SUMMARY 
     Embodiments of the present invention relate generally to door locking systems for use in connection with trash compactor systems for preventing inadvertent opening of the main door during a compaction cycle. They provide a trash compactor main door interlock, comprising an actuator configured to indicate that a compaction cycle has begun; and a lock system configured to be activated by the actuator and to restrain the main door from opening. The actuator may be mechanically or hydraulically activated. 
     In a specific embodiment, the lock system comprises a vertical rod, a hinge member, and a horizontal rod. The actuator causes the vertical rod to press against the hinge member, pressure on the hinge member causes the horizontal rod to extend toward a handle of the main door, and extension of the horizontal rod causes the rod to restrain a handle of the main door. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a front plan view of one embodiment of a main door interlock. 
         FIGS. 2 and 3  show a front view of the internal workings of a compactor unit with a mechanical actuator and main door interlock. 
         FIG. 4  shows a specific embodiment of a mechanical actuator. 
         FIGS. 5 and 6  show a mechanical actuator in place on a compactor unit. 
         FIG. 7  shows a view of an optional trash door lock. 
         FIG. 8  shows a side perspective view of a hydraulic interlock actuator. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments described provide a main door interlock that prevents the front main door handle of the trash compactor unit from being pulled open when the platen is in motion, thus preventing the door from opening. The main door interlock may be mechanically, electrically, or hydraulically activated. In either instance, the main door mechanisms are similar. Alternate embodiments provide a main door interlock that can prevent the handle from being opened at any time before the final compaction has taken place. This may be accomplished by an electrical circuit, a solenoid system that be insert and extract a pin from the door handle, or any other appropriate means. 
     In a first mechanical embodiment, the mechanical design allows the movement of the trash compacting platen to activate the interlock. This way, any time a compaction cycle occurs, the main door cannot be opened. In a second hydraulic embodiment, the hydraulic pressure used to push the cylinders behind the platen is secondarily used to activate the interlock. Activation of the interlock will thus lock the main door any time a compaction cycle takes place. Although not shown, it is understood that any other mechanisms may be used to ensure that the main door remains closed for the desired duration, either when the platen is in motion or until the final compaction cycle has occurred. 
     In the embodiment shown in  FIG. 1 , trash compactor unit  10  is shown having its front cover removed so that the inner workings are visible. Unit  10  has a main door  12  with a handle  14  and a waste flap  15 . In use, trash is delivered to the interior of the unit through waste flap  15  (which is typically a trash door that opens outwardly to create a trash chute), into a trash container (which is typically a specially designed cardboard box) positioned in the interior of the unit  10 . 
     An actuator  16  or  18  is provided that is configured to indicate that a compaction cycle has begun. For example, the actuator  16  may be a mechanical actuator that physically actuates or moves or otherwise alerts the door locking system that the platen has begun movement. In one embodiment, actuator  16  may have a portion that provides an internal feature or hinge that cooperates with a portion of the platen, such that when the platen physically moves against or pushes the feature or hinge, it indicates that the compaction cycle is in progress. When the actuator  16  is not being pushed or moved by the platen, the remaining portions of the main door interlock (described below) maintain a default open position and the main door remains in its unlocked position. 
     One specific mechanical actuator  16  is shown in  FIGS. 2-4 . In this specific embodiment, the actuator  16  engages the main door interlock (to restrict access to the main door) by actuating a lock-activating plunger upon movement of the compaction platen  50 . As shown in  FIG. 2 , when the platen  50  is in its upward-most position (i.e., when a compaction cycle is not underway), the compaction platen  50  presses up against or otherwise lifts an arm member  54  that keeps the lock-activating plunger raised. When the plunger is raised, it does not engage the main door interlock. In other words, without the activation of the lock-activating plunger against the main door interlock, the main door interlock maintains a default open position. When the platen  50  begins movement (i.e., when a compaction cycle is underway), the motion of the arm  54  causes the mechanical actuator  16  system to extend a plunger to interact with the main door interlock system in order to cause the door to lock and remain in a locked position (as shown in  FIG. 3 ). 
     As shown in schematic  FIG. 2 , when the platen  50  is in its raised position, it causes actuator  16  to take a first platen-contacting position. In this position, a roller ball feature  52  positioned at and end of an arm  54  contacts the platen, which indicates to the system that the platen is in its home position (i.e., that a compaction cycle is not currently underway). Arm  54  may be a movable (e.g., translatable and rotatable) arm that is a part of a spring-loaded linkage  56 . Arm  54  may have its non-roller ball end fixedly secured to an internal portion of the unit  10  to provide a lever force. In its home (uppermost) position, the platen  50  exhibits an upward force on the arm  54  and the linkage  56 , keeping the main door open. In other words, when the platen  50  is up, the lock is open. 
     As shown in schematic  FIG. 3 , when the platen  50  is in a lowered position (or begins the lowering process for a compaction cycle), actuator  16  takes a second platen-distanced position (referred to as “d”). In this position, the movement of the roller ball feature  52  and arm  54  indicates to the system that the platen has moved away from the home position and that a compaction cycle is underway. This causes arm  54  to scissor downwardly against the spring-loaded linkage  56 , which also causes downward movement of a translatable bar  60 , which causes a plunger  58  (shown in  FIG. 4 ) to extend downwardly and activate the door lock system (described in more detail below). When the platen moves back up, it pulls the roller ball arm back up, and consequently raises the translatable bar  60 , which pulls the plunger back up, which releases the main door interlock components described below, allowing the door to be opened. 
     A specific embodiment of one mechanical actuator  16  is shown in  FIG. 4 . Roller ball feature  52  is connected to arm  54 , and the spring loaded linkage  56  provides a pivot point to allow the arm  54  to navigate movement against the platen  50 . Linkage  60  translates the motion from arm  54  into downward movement of actuator  16 . Thus, movement of arm  54  against platen  50  causes movement of the linkage bar  60 , which causes movement of the plunger  58 .  FIG. 4  also shows an override switch  62  that may extend to the outside of the compactor to allow a user to lock or unlock the main door independently from the main door interlock system. 
       FIG. 5  shows a mechanical actuator  16  (with arm  54 ) in place on the unit  10 .  FIG. 6  shows a cut-away view which illustrates the plunger  58  in more detail. The plunger  58  may be associated with a spring  66  (as well as with the bar  60 ), which spring loads actuator  16  elements  56 ,  54 , and  52  downwards. As shown in  FIG. 7 , plunger  58  navigates the division between an upper control box and the main door  12 . A trash door lock  64  may also be associated with the plunger  58 , such that when the main door interlock is activated in order to lock the main door, the trash door (or waste flap)  18  is also locked. This adds one additional layer of safety to the system. 
     Although one specific actuator system  16  is described, it should be understood that other mechanical means for accomplishing the actuator function may be used and are considered within the scope of the invention. The general concept is that movement of the platen  50  causes an actuator system  16  to activate a lock for the main door (and optionally, activate a lock for the trash door), and other mechanical interfaces may be used. 
     Alternatively, the actuator may be a hydraulic actuator  18 , as shown in  FIG. 8 . In this embodiment, the main door interlock restricts access to the main door by using hydraulic fluid to activate the hydraulic actuator  18 . In a specific embodiment, there is provided a hydraulic fluid connection  20 , a body actuator  22 , and a plunger  24 . The hydraulic pressure used to push the cylinders behind the platen is also used to activate the remaining interlock portions. When the platen is activated, the hydraulic actuator extends the plunger  22  to interact with the main door interlock portions, which indicates that the compaction cycle is in progress. When the plunger is not activated, the main door interlock portions maintain a default open position and the main door remains in its unlocked position. 
     In either embodiment, the actuator  16  or  18  indicates to the system that a compaction cycle is in progress by detecting movement of the platen. It should be understood that there may be other ways to indicate to the system that the compaction cycle is in progress, such as an electrical switch, a solenoid, or any other appropriate indicator or notifier system. 
     Once the actuator is pushed down or otherwise activated, the main door interlock system  20  locks the main door  12 . In a specific embodiment, system  20  is configured to restrict movement (e.g., opening) of the main door handle  14 . Although one specific interlock system  20  is described with relating portions below, it should be understood that other mechanical means for accomplishing the locking function may be used and are considered within the scope of the invention. 
     In a specific embodiment, the locking system  20  may include a vertical rod  26 , a hinge member  28 , and a horizontal rod  30 , all of which are associated with one another or otherwise mechanically engaged. Once actuator  16  or  18  is activated by the beginning of a compression cycle, it applies pressure to the vertical rod  26 . This pressure may either be applied by an end of the actuator  16  or by the plunger  22 ,  58 . The pressure from the actuator causes the vertical rod  26  to move down (in the embodiment shown, but it should be understood that the actuator  16  or  18  may be below the vertical rod and thus cause the rod to move up) and press against the hinge member  28 . 
     In a specific embodiment, hinge member  28  comprises two hinge legs  32 ,  34  connected at a point  36 . Point  36  changes the vertical force “V” from the vertical rod  26  into a horizontal force “H.” Pressure on hinge member  28  thus causes the horizontal rod  30  to extend toward the handle  14  of the main door  12 . Horizontal rod  30  may have a first securing feature  38  and handle  14  may have a corresponding second securing feature  40 . In a particular embodiment, the first securing feature  38  on the rod  30  is a pin or other protrusion that extends from the end of rod  30 , and the corresponding second securing feature  40  on the handle  14  is an opening or indentation. It should be understood that either of pin or opening may be positioned on either of the rod  30  or the handle  14 . It should further be understood that alternate securing features may be used, as long as cooperation therebetween restricts movement of the handle or the door. Features  38  and  40  are dimensioned and configured such that when they are engaged, the handle  14  cannot be pulled and the main door  12  cannot be opened. In the embodiment shown, extension of the horizontal rod  30  causes the rod  30  to restrain the handle  14  of the main door. 
     Thus, for the mechanical version of the embodiments shown and described, there may be two hinged interfaces. A first hinged interface provides the actuator  16  (which indicates that the compaction process has begun and activates the interlock system) and a second hinged interface  28  provides the main door interlock (which secures the main door handle from being opened). The spacing and positioning of these hinges is intended to maximize space considerations on the trash compactor unit  10 , while providing the functional advantages described. 
     Changes and modifications, additions and deletions may be made to the structures and methods recited above and shown in the drawings without departing from the scope or spirit of the invention and the following claims.