Abstract:
An emergency floatation system for an aircraft includes an actuator box assembly that activates the floatation system either electrically or manually. The actuator box assembly is separated from a valve assembly of an inflation reservoir and provides an interface between an electromechanical trigger system and a redundant mechanical trigger system. The actuator box includes a pivot member that provides an interface for the redundant trigger systems and an output actuator. For normal operation a button in the cockpit is pressed which sends an electrical signal to an electromechanical actuator in the actuator box assembly. The electromechanical actuator rotates the pivot member, which operates the output actuator and opens the valve assembly. Alternatively, should the electrical system of the aircraft fail, the pilot or other occupant may activate the mechanical trigger system, thereby rotating the pivot member and activating the output actuator to open the valve assembly.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. Provisional Patent Application Ser. No. 60/776,348, filed Feb. 24, 2006, which is hereby incorporated in its entirety by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to triggers for emergency equipment used in aircraft. More specifically, the invention relates to redundant triggers for an inflation valve used to inflate emergency floatation devices used on aircraft. 
     BACKGROUND OF THE INVENTION 
     Emergency flotation devices are required on many aircraft to provide emergency assistance to passengers and to save the aircraft in the event the aircraft experiences an emergency situation and is forced down in water. Emergency flotation devices generally include systems designed to float the aircraft, systems for emergency life rafts and life vests for individual occupants. 
     One example of an airplane flotation system is shown in U.S. Pat. No. 1,776,865. The system includes inflatable bags located in a forward portion of an airplane and is manually operated by a pilot. The bags are stored in a non-inflated state within closed compartments. The system utilizes pressure cylinders to sequentially unlock doors of the compartments and inflate the inflatable bags. During operation, the pilot activates the pressure cylinder by pulling a first pull cord attached to a valve, thereby releasing pressurized fluid. After inflation, the pilot is required to second pull a cord that places the pressure cylinder into an intermediate position to block further fluid flow into the bags. The system provides no redundant trigger system. 
     U.S. Pat. No. 2,264,321 to Manson, describes a life-saving device that includes an inflatable life raft that is arranged in a compartment on the side of a vehicle such as an airplane. The compartment is closed by a pair of hinged doors that are spring-loaded to urge them into an opened position. The doors are held closed by pins that extend through meshing lugs that are included on the doors. A pull cord is secured to the pins and a valve on an inflating-fluid container so that pulling on the cord sequentially removes the pins from the lugs and operates the valve to permit the flow of fluid from the container to the raft. The cord fully disengages from the fluid container after the valve is operated. Similar to the previously described floatation system, this life-saving device provides no redundant trigger system. 
     In another example of a safety system that may be used for helicopters, described in U.S. Pat. No. 3,340,842 to Winslow, a plurality of balloons fluidly coupled to a pressurized tank of carbon dioxide are employed throughout a vessel. The tank includes an outlet valve fitting that may be operated either by an electrically operated control or a manually operated pull. Both the electrically operated control and the manual pull are coupled directly to the valve fitting on the tank. As a result, replacement of either of the electric control or manual pull would require that the tank be handled, which creates a risk of damaging the tank. In addition, a larger space is required to mount the tank in the vessel because that space must be large enough to accommodate the controls in addition to the tank. Furthermore, because the manual and electric control connect directly to the valve there is no mechanism to assure that one control will not hinder the operation of the other. For example, if the movement of manual control lever was restricted, there is no mechanism that would assure that electric control could be used to release the inflation fluid. 
     In view of the above, there exists a need for an actuator box assembly for an emergency flotation system that provides the combination of manual and electrical trigger systems all within one assembly that may be mounted separate from the inflation fluid source. 
     SUMMARY OF THE INVENTION 
     The floatation system includes an emergency inflatable device, a source of pressurized inflation fluid, redundant trigger systems and an actuator box assembly that provides an interface between the redundant trigger systems. The actuator box assembly consists of a housing assembly, redundant input actuators which form parts of the redundant trigger systems, an output actuator and a pivot member that mechanically couples the actuators. The input actuators and the output actuator are mechanically coupled by the pivot member so that actuation of either input actuator activates the output actuator to deploy the floatation system. The input actuators may include both electromechanical and purely mechanical actuators. For example the actuator box assembly may serve as a way to trigger the discharge of the pressurized inflation fluid electrically as well as manually, if needed. In an embodiment, the electromechanical actuator is a linear actuator that includes an arm that translates when electrically activated and engages a portion of the pivot member. The linear actuator can apply a large amount of force on the pivot member to ensure valve activation and the dimensions of the pivot member may be selected to provide a mechanical advantage when utilizing the manual trigger assembly. 
     The actuator box assembly is configured so that it may be placed anywhere in the vessel between the trigger controls and the inflation fluid source. The actuator box assembly is primarily designed to provide an interface between the redundant trigger systems and the source of inflation fluid and to initiate inflation of the emergency inflatable by actuating a valve to allow the flow of pressurized fluid from the fluid source to the inflatable. In an embodiment, the primary trigger system is electrically activated. However, if the primary trigger system fails, the system includes a means to manually actuate the valve so that the inflatable may be deployed. 
     Such a manual backup trigger system may be especially important for situations where there is an electrical failure and the electrical firing of the system is not possible. For example, if a helicopter is forced to land in the water and deploy emergency floats, the pilot can actuate the valve electrically to discharge the inflation fluid to inflate the inflatable by simply pushing a button in the cockpit. However in the event that the electrical system on the helicopter fails, the pilot can also activate the valve to discharge the inflation fluid manually by pulling a pull cable or a lever or by squeezing a mechanical trigger. 
     These and other features and advantages of the present invention will be appreciated from review of the following detailed description of the invention, along with the accompanying figures in which like reference numerals refer to like parts throughout. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is schematic of the actuator box assembly in an emergency floatation system. 
         FIG. 2  is an isometric partial exploded view of the actuator box assembly. 
         FIG. 3  is another isometric exploded view of the actuator box assembly. 
         FIG. 4  is a top view of the assembled actuator box assembly with the lid removed to show the contents as they are assembled in a non-deployed state. 
         FIG. 5  is a top view of the assembled actuator box assembly with the lid removed to show the contents as they are assembled in a deployed state. 
         FIG. 6  is a top view of the assembled actuator box assembly with the lid removed to show the contents as they are assembled in a manually deployed state. 
         FIG. 7  is a top view of an alternative embodiment of the assembled actuator box assembly with the lid removed to show the contents as they are assembled in a manually deployed state. 
         FIG. 8  is a top view of an alternative embodiment of the assembled actuator box assembly with the lid removed to show the contents as they are assembled in a manually deployed state. 
         FIG. 9  is a top view of an alternative embodiment of the assembled actuator box assembly with the lid removed to show the contents as they are assembled in a manually deployed state. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an emergency flotation system  10  in accordance with the present invention will be described. Emergency flotation system  10  generally includes a pressurized fluid source, such as an inflation reservoir  12 , that stores a pressurized fluid for selectively inflating an emergency inflatable device  14 , such as a life raft. The pressurized fluid may be any fluid capable of inflating an inflatable device, such as air, nitrogen or carbon dioxide. A pressure line  16  fluidly links inflation reservoir  12  with inflatable device  14  through a valve  20  and a latching assembly  18 . Valve  20  is normally closed so that fluid communication between inflation reservoir  12  and inflatable device  14  is prevented. 
     Emergency inflatable device  14  is preferably stored in an emergency compartment  15  and latching assembly  18  includes a plurality of latches  19  that are used to maintain emergency compartment  15  in a locked state. In the present embodiment, latches  19  may be configured so that they are activated and unlocked when valve  20  is opened and fluid is released from inflation reservoir  12 . The inflation fluid is free to flow to inflatable device  14  after latches  19  are unlocked. It should be appreciated, however, that any latches known in the art may be employed and it is not necessary that the latches be pressure activated. For example, separate manual or electromechanical latches may be used and pressure line  16  may extend directly from valve  20  to inflatable device  14 . 
     Floatation system  10  includes redundant triggering systems for activating the system and deploying inflatable device  14 . In the present embodiment, an electromechanical (EM) triggering system  27  is provided that may draw power from either a main power system  26  or an emergency power supply  24  included in the vessel. A purely mechanical backup triggering system  28  is also provided for redundancy. As will be described in greater detail below, the redundant triggering systems interface at an actuator box assembly  30  so that operation of either will trigger deployment of the floatation system  10  and so that operation of one trigger system is not hindered by the other. 
     EM triggering system  27  includes a switch  22 , a communication line  23  and an electromechanical input actuator  34  that is located within actuator box assembly  30 . Switch  22 , which may alternatively be a button or knob, preferably is located in the cockpit of the vessel. Switch  22  is configured so that toggling, pushing or turning it results in an electrical signal being sent through communication line  23  to EM input actuator  34 . The electrical signal may be any signal capable of activating EM input actuator  34 , such as a DC current. 
     Mechanical triggering system  28  includes a handle (not shown) that is coupled to a purely mechanical input actuator  32 , such as a pull cord or mechanical linkage or a combination thereof. Mechanical triggering system  28  is provided so that if EM triggering system  27  is inoperative (e.g., due to a power failure), floatation system  10  may still be deployed. It should be appreciated that the handle of mechanical triggering system  28  may be replaced by a lever or squeeze trigger if desired. 
     Actuator box assembly  30  provides an interface between EM triggering system  27  and mechanical triggering system  28  so that either may be used to deploy floatation system  10 . In particular, actuator box assembly  30  provides a mechanical coupling between EM input actuator  34  and mechanical input actuator  32 . It is desired to provide such an interface so that both trigger systems are not required to extend the full distance between the trigger device (i.e., switch  22  or the handle) and valve  20  of inflation reservoir  12 . Actuator box assembly  30  also allows the associated EM and mechanical actuators  34 ,  32  to be mounted anywhere on the vessel separate from inflation reservoir  12 . 
     Referring to  FIGS. 2-4 , an embodiment of actuator box assembly  30  according to the present invention will be described. Actuator box assembly  30  generally includes a housing assembly, mechanical input actuator  32 , electromechanical input actuator  34  and a mechanical output actuator  36 , which are coupled together through a pivot member  38 . The three actuators are coupled to each other within actuator box assembly  30  so that operation of either input actuator  32 ,  34  is sufficient to activate output actuator  36  and so that each input actuator is free to activate output actuator  36  without being hindered by the other input actuator. 
     The housing assembly includes a housing body  33 , a cover  35  and a cover seal  37 , such as a gasket. EM actuator  34 , pivot member  38  and portions of mechanical input actuator  32  and mechanical output actuator  36  are mounted within housing body  33  and cover  35  is mounted to housing body  33  to enclose the components. Cover seal  37  is placed between housing body  33  and cover  35  during assembly so that the housing assembly is substantially watertight. 
     Housing body  33  includes boss  42  that is configured so that pivot member  38  may be rotatably mounted within the housing assembly. Boss  42  is generally cylindrical and extends from an inside bottom surface of housing body  33 . In addition, a plurality of actuator mounting features  39 , such as apertures, or threaded holes, are included in housing so that electromechanical actuator  34  may be mounted inside housing body  33  with mechanical fasteners, such as screws. 
     A connector mount  44  is also included so that an electric connector  46 , preferably a military standard waterproof connector, may be mounted to housing body  33  to provide an electric connection between portions of communication line  23  inside and outside of the housing assembly allowing actuator box assembly  30  to be easily removed from floatation system  10 . The housing assembly also includes through holes  49  so that portions of mechanical input actuator  32  and mechanical output actuator  36  may pass through the wall of housing body  33 . Preferably, seals are provided at each of through holes  49  so that the mechanical actuators may pass through housing body  33  without affecting the water resistance of the housing assembly. Housing body  33  also includes mounting pads  50  that allow actuator box assembly  30  to be fastened to the vessel. 
     Housing body  33  and cover  35  may be constructed from any material sufficient to protect the actuators and pivot member  38  from damage caused by ingress of liquid or mechanical shock. For example, suitable materials include plastics such as polycarbonate, composite materials such as carbon fiber, and metals such as aluminum, titanium and steel. Housing body  33  and cover  35  may be molded, machined or die cast. 
     Pivot member  38  is an elongate lever arm that includes a pivot collar  60  that is configured to be mounted on boss  42 . Pivot collar  60  is configured to receive a reduced diameter mounting portion  63  of boss  42 . A threaded bore  61  extends into boss  42  so that a fastener is inserted into boss  42  through pivot member  38  to retain pivot member  38  on boss  42 . It should be appreciated that any type of fastener may be used, such as screws, clips, cotter pins, etc. Furthermore, it should be appreciated that although the fastener preferably is removable, a permanent fastener may be employed if desired. 
     In the present embodiment, pivot member  38  is generally Z-shaped and includes a first portion  65  configured to interface EM input actuator  34  and a second portion  66  configured to interface mechanical input actuator  32 . Pivot collar  60  is located between first and second portions  65 ,  66  of pivot member  38 . When pivot member  38  is mounted in housing body  33  pulling on one portion of pivot member  38  causes rotation of pivot member  38  in the same direction as pushing on the other portion. It should be appreciated that easy rotation of pivot member  38  relative to boss  42  may be assured by bearings, bushings or any lubrication desired. 
     It should also be appreciated that the pivot member may be any shape and may include arcuate camming surfaces. For example, as shown in  FIG. 7  the pivot member may be a disk  71  that is mounted at its center (not shown), or mounted eccentrically (shown), to boss  42 . As a further example, pivot member may be triangular or any other polygonal shape rotatably coupled to boss  42 . As a still further alternative, the pivot member may be a cart that translates linearly on guides or tracks. In addition, pivot member  38  may be dimensioned so that a mechanical advantage is provided to any particular actuator. For example, as shown, mechanical input actuator  32  is coupled to pivot member or disk  71  further radially outward than output actuator  36 , which results in greater force applied to output actuator  36  than is input to input actuator  32 . 
     Referring again to  FIGS. 2-4 , a biasing assembly  67  is also included in actuator box assembly  30  that biases the rotation of pivot member  38  away from the direction of rotation used to deploy floatation system  10 . Biasing assembly  67  includes a spring  68  that extends between a boss  69  of housing body  33  and pivot member  38 . The spring rate of spring  68  is selected so that during operation the force exerted by input actuators  32 ,  34  on pivot member  38  can overcome the counteracting force exerted by biasing assembly  67  on pivot member  38 . Biasing assembly  67  may be any device capable of biasing the rotation of pivot member  38 . In the present embodiment, spring  68  of biasing assembly  67  is a helical spring, but it should be appreciated that spring  68  may be any spring device such as a torsional spring. 
     EM input actuator  34  is a linear actuator that includes an electric motor  70 , an optional gear box  72  and a linear drive  74  that includes an extendable actuator arm  76 . A pivot member connector  78  of actuator arm  76  is configured to be engageable with pivot member, i.e., by abutting pivot member  38  so that extension of actuator arm  76  causes pivot member  38  to rotate. Pivot member connector  78  also includes guide arms  80  that prevent disengagement between pivot member  38  and connector  78  when actuator arm  76  is extended but allow disengagement when pivot member  38  is rotated by mechanical trigger system  28 , as described in greater detail below. It should be appreciated that EM input actuator  34  may be custom made or any of a number of commercially available actuators sufficient to rotate pivot member  38  as required. 
     Linear drive  74  converts the rotational movement provided by electric motor  70  and gear box  72  into linear motion of actuator arm  76 . Linear drive  74  may be any type of linear drive known in the art such as a lead screw, a ball screw, an acme screw or a rack and pinion. An embodiment of the present invention including a lead screw  81  is shown in  FIG. 8 . It should also be appreciated that the linear actuator may be any type of linear actuator and need not include a rotating electric motor. For example, as shown is  FIG. 9 , the EM input actuator may be a solenoid  83  including an armature  85  similarly coupled to pivot member  38 . It should further be appreciated that the linear actuator may be replaced by any electromechanical actuator that is configured to rotate pivot member  38 . For example, any type of electric motor, such as a stepper motor or constant reluctance motor, may be coupled directly, or through a gear drive, to pivot member  38  without utilizing linear drive  74 . 
     Mechanical input actuator  32  is a pull cable. A first end of actuator  32  is coupled to the mechanical trigger (i.e., the handle) of mechanical trigger system  28  that is mounted in the vessel so that it is accessible to the operator. A second end of actuator  32  is coupled to pivot member  38  inside actuator box assembly  30  so that pulling the handle rotates pivot member  38 . The pull cable is preferably housed in a cable housing that protects the cable from damage. In addition, the cable housing preferably includes a friction reducing lining so that the pull cable may freely slide within the cable housing. 
     Mechanical output actuator  36  is also a pull cable in the present embodiment. A first end of output actuator  36  is coupled to pivot member  38  so that rotation of pivot member  38  by either input actuator  32 ,  34  pulls output actuator  36 . A second end of output actuator  36  is coupled to valve  20  so that pulling output actuator  36  causes valve  20  to open so that floatation system  10  is deployed. 
     Referring to  FIGS. 4-6 , operation of actuator box assembly  30  will be described. During normal operation of the vessel, inflation device  14  of floatation system  10  remains stowed and actuator box assembly is in a non-deployed state, as shown in  FIG. 4 . In the non-deployed state, actuator arm  76  is in a retracted position and pivot member  38  abuts connector  78  under the influence of biasing assembly  67 . The abutment between pivot member  38  and connector  78  limits the rotation of pivot member  38  in the counter-clockwise direction. The force applied by biasing assembly  67  assures that pivot member  38  remains in contact with connector  78  and that pivot member  38  will not rotate under the influence of small movements of mechanical input actuator  32  or mechanical shocks exerted on actuator box assembly  30 . 
     In an emergency, floatation system  10  is preferably electrically activated by EM trigger system  28 . An operator utilizes EM trigger system  28  by activating switch  22 , which causes an electrical signal to travel through communication line  23  to EM input actuator  34 . The electrical signal causes EM input actuator  34  to extend actuator arm  76  which forces pivot member  38  to rotate in the clockwise direction as shown in  FIG. 5 . In particular, extension of actuator arm  76  and engagement of connector  78  with pivot member  38  causes forcible abutment between connector  78  and pivot member  38 , thereby causing pivot member  38  to rotate. Clockwise rotation of pivot member  38  causes pivot member  38  to pull output actuator  36 , which activates valve  20  to deploy floatation system  10 . 
     In the event that the electrical triggering of valve  20  is not successful, for example during a complete electrical failure, mechanical trigger system  28  may be used to deploy floatation system  10 . The operator may utilize mechanical trigger system  28  by pulling the pull cable (i.e., mechanical input actuator  32 ) by grasping and pulling the handle. Pulling the pull cable causes pivot member  38  to rotate in the clockwise direction, as shown in  FIG. 6 . Rotation of pivot member  38  causes output actuator  36  to be pulled which causes valve  20  to switch to an open position. Once open, valve  20  allows pressurized fluid to flow from the inflation reservoir and into emergency inflatable device  14 . 
     Each input actuator  32 ,  34  is free to operate without being hindered by the other. When EM trigger system  27  is utilized, it causes pivot member  38  to rotate clockwise which makes the pull cable of mechanical input actuator  32  less taut. On the other hand, when mechanical trigger system  28  is utilized, pivot member  38  rotates and because EM input actuator  34  is engageable but not fixedly coupled with pivot member  38 , pivot member  38  is free to rotate away from connector  78  without hindrance. 
     While actuator box assembly  30  is described in the context of a trigger for an emergency floatation system, those skilled in the art will appreciate that many additional uses for actuator box assembly  30  are readily identifiable. Actuator box assembly  30  could be used in any electromechanical trigger system where a fully manual backup system is advantageous.