Abstract:
An emergency exit system for use on a helicopter or other aircraft includes a frame ( 4 ) defining an opening ( 6 ) for receiving a panel ( 8 ) to close the opening ( 6 ); a plurality of latches ( 10, 117 ) for releasably securing the panel ( 8 ) in the opening ( 6 ); a plurality of release mechanisms ( 12 ); a cable ( 45, 118 ) extending around at least a major portion of the frame ( 4 ) for releasing the panel ( 8 ); and a plurality of actuators ( 14 ) strategically located around the opening and connected to the cable ( 45, 118 ), whereby actuation of any one of the actuators ( 14 ) causes simultaneous release of all of the latches ( 10, 117 ) so that the panel ( 8 ) can be jettisoned.

Description:
This application claims the benefit of provisional application 60/054,794 filed Aug. 5, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to an emergency exit system and in particular to an emergency exit system for use on a helicopter or other aircraft. 
     Vehicle accidents occurring in water have a lower survival rate than accidents occurring on land. In water accidents, the vehicles usually sink very rapidly, either in an upright or inverted position. Underwater conditions are drastically different from land based conditions. Visibility is reduced—the majority of people can see only 1.5 meters underwater and 3.1 meters in the best lit conditions. Survivors of a crash or forced landing must depend on their breath-holding ability to make a successful escape. Generally, a person&#39;s breath-holding ability is reduced 25-50% in water under 15° C. Maximum breath-holding time can be as short as 10 seconds. Survivors are often disoriented due to the sudden immersion in water, loss of gravitational references, poor depth perception, nasal inhalation of water and darkness. Disorientation is magnified when the vehicle is inverted. Under the latter condition, finding a handle to jettison an escape door or window, which is a simple procedure to execute in an upright position on dry land, can be a most challenging task even if the handle is only a few centimeters away from the survivor&#39;s hand. 
     Usually handles for open escape doors or windows are small, and are positioned between knee and chest level. The various positions would not be obvious to the survivor unless he or she is familiar with the particular escape system Most existing mechanisms are adapted to remove an entire door or window, including the frame, requiring a complicated jettison mechanism, which is not always dependable. Moreover, existing systems do not provide feedback to indicate that the door, window or hatch as been successfully jettisoned. 
     GB-A-761 627 and U.S. Pat. No. 3,851,845 disclose systems for the jettisoning of aircraft canopies or doors which are inappropriate for use in a door or window release. The U.S. reference teaches the use of lever or a lever and a handle combination for releasing a door. When submerged in water such a system could be difficult to operate, particularly when it is necessary to operate a handle and a separate lever to effect release of the door. 
     BRIEF SUMMARY OF THE INVENTION 
     The object of the present invention is to provide an emergency exit system of the type which includes a plurality of actuators adapted&#39;to operate independently of one another to effect release of a window or door panel to provide an escape exit. 
     Accordingly, the present invention relates to an emergency exit system including a frame for mounting in a vehicle, said frame having an opening for closing by a panel, a plurality of spaced apart latch means for releasably latching said panel in the frame; release means for simultaneously releasing all of said latch means; and principal actuation means located at a plurality of locations around the periphery of said frame for actuating said release means when any of said actuation means is actuated, characterised by cable means forming part of said release means and extending around a substantial portion of said frame to interconnect the release means associated with each said latch means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described below in greater detail with reference to the accompanying drawings, which illustrate preferred embodiments of the invention, and wherein: 
     FIG. 1 is a perspective view of a window emergency exit system in accordance with the invention; 
     FIGS. 2 and 3 are front elevation views of the interior of the exit system of FIG. 1 with parts removed and showing the plungers in the panel latching and panel release positions, respectively; 
     FIG. 4 is a isometric view of portions of actuation and release mechanisms used in the exit system of FIG. 1; 
     FIG. 5 is a schematic, partly a sectioned view taken along line  5 — 5  of FIG. 1; 
     FIG. 6 is an elevation view of the interior of the exit system of FIG. 1 with parts removed; 
     FIG. 7 is a front elevation view of the interior of a door emergency exit system; 
     FIG. 8 is a front elevation view of the door exit system of FIG. 7 with parts removed; 
     FIG. 9 is a schematic, cross section taken generally along line,  9 — 9  of FIG. 7; 
     FIG. 10A is a front view of a hinge assembly used in the exit system of FIG. 7; and 
     FIG. 10B is a front view of a plate and a section of cable for releasably retaining the hinge assembly of FIG.  1   
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 to  3 , one embodiment of the emergency exit system, which is generally indicated at  2 , is a window for mounting in the fuselage of an aircraft such as a helicopter (not shown). However, the system may also be a door, a hatch or any other type of exit adapted for mounting in a closed body such as the body of a vehicle, e.g. a car, bus or truck, the fuselage of an airplane or a wall of a building. 
     Generally, the emergency exit system  2  includes a rectangular frame  4  defining a central opening  6 , a closure panel  8  such as a metal sheet or window releaseably secured in the opening  6  by a plurality of latches  10  extending from the frame  4 ; a release mechanism  12  (FIGS. 2 and 3) in the frame  4  and an actuation mechanism on the inner side of the frame  4  including four bars  14  (FIG.  1 ), which are independently operable to simultaneously effect the release of all of the latches  10  to enable jettisoning of the closure panel  8  to provide an emergency exit. 
     The frame  4  includes interconnected exterior and interior panels  16  and  18 , respectively. The interior panel  18  is sufficiently thick to contain the actuation mechanism  12  (FIG. 2 or  3 ). Four closed compartments  20  extend from the corners of the inner panel  18  for receiving the bars  14  therebetween. The compartments  20  contain parts of the release mechanism  12  and an emergency lighting assembly  21  (FIG.  6 ), both of which are described in detail below. 
     In contrast to prior art emergency exit systems, the exit system  2  of the present invention includes a plurality of actuation bars  14 . The bars  14  are mounted in obvious locations, i.e. they extend along the interior of the sides  22  and the top and bottom ends  23  and  24 , respectively of the frame  4 , so that they can be easily located and accessed, thus significantly improving the chances of escape and survival of trapped survivors. Each bar  14  includes an elongated cylindrical body  25  with a press fitted lever  26  at one end thereof. The bars  14  are individually connected to the release mechanism  12  in such a manner as to be independently operable. Actuation of any one of the bars  14  will simultaneously disengage all of the latches  10  to release the panel  8  from the frame  4 . This minimizes the number of operations and amount of energy required by the survivor to release the panel  8 . All of the energy of the operator will be applied to the release of the panel  8  rather than for actuation of the remaining bars  14 . Moreover, if one bar  14  malfunctions, another may be used to serve the same function. The panel  8  is jettisoned by pulling any one of the bars  14  towards the operator and away from the frame  4 . 
     The bars  14  are rotatably mounted relative to the compartments  20  between first and second limit positions. In the first limit position, the panel  8  is secured in the opening  6 . In the second limit position, the panel  8  is released from the frame  4 . 
     Each release mechanism  12  is connected to one end of each bar  14 . Referring to FIGS. 2 to  4 , rotation of one bar  14  is transmitted to its associated release mechanism  12  and then to the plurality of latches  10  to simultaneously retract each latch  10  inwardly into the frame  4  to release the panel  8 . The release mechanism  12  is switchable between a locked or latched position (FIG. 2) in which the latches  10  extend inwardly from the frame  4  and a release position (FIG. 3) in which the latches  10  are retracted into the frame  4 . 
     Each release mechanism  12  is designed to translate rotational movement of the bar  14  and a lever  26  at one end of the bar into movement necessary to disengage the latches  10 . Referring to FIG. 4, each release mechanism  12  includes a helical gear or rack  28  mounted on a shaft  29  near one end thereof. The gear  28  is connected by a gear or pinion  30  and a shaft  31  to a lever  26 . Rotation of the lever  26  around the longitudinal axis of the shaft  31  results in a corresponding rotation of the shafts  29  and  31 . The shaft  29  is rotatably mounted in ball bearings (not shown) in arms  33  and  34  of a generally C-shaped bracket  35 . The shaft  31  is also mounted in the bracket  35  perpendicular to the shaft  29 . It will be appreciated that the bracket  35  and the shafts  29  and  31  are housed in the compartments  20 . The end of the shaft  29  extending through the arm  34  of the bracket  35  extends through an opening in the frame  4  and carries a pinion  40 . The pinion  40  meshes with a rack  42  for imparting longitudinal movement thereto when the pinion is rotated. The pinion  40  is retained on the shaft  29  by a key (not shown) and a nut  44 . 
     A cable  45  extends through and is freely slidable in the rack  42 . The cable  45  extends around idler pulleys  47  located at the corners of the frame  4 . A conventional cable tensioner  48  (FIGS. 2 and 3) maintains the cable  45  under the desired tension. A stop  50  is fixedly mounted on the cable  45  for engaging one end of the rack  42 . When the rack  42  is moved in one direction (indicated by arrows A in FIG.  2 ), it pushes against the stop  50  to move the cable  45  in the same direction. Movement of the cable  45  causes rotation of a second lever  54  (FIG. 4) mounted in the frame for operating a latch  10 . The lever  54  includes a tapering body  56  with a generally U-shaped notch  57  in an outer end thereof for receiving a pin  59  attached to the cable  45 . Thus, movement of the cable  45  will cause rotation of the lever  54 , the inner end  60  of which is rotatably mounted in the frame  4 . Such inner end  60  of the lever  54  includes teeth defining a pinion for engaging a rack  62  slidably mounted in the frame  4 . The rack  62  forms part of the latch  10 . A pin  63  with a tapered outer end extends outwardly from the rack  62  for retaining the panel  8  in the frame  4 . When the pin  63  is retracted, the panel  8  is released for jettisoning. 
     It is readily apparent that rotation of one lever  26  will cause movement of the cable  45 , and consequently simultaneous release of all of the latches  10 . Movement of the lever  26  and the cable  45  in the opposite direction will result in extension of the pin  63  to the latched or locking position (FIG.  4 ). In the locked position the pins  63  engage grooves or indentations  65  (FIG. 2) in the panel  8 . From FIGS. 2 and 3, it will be noted that a rack  42  and pinion  40  arrangement is associated with each bar  14 , so that rotation of any bar  14  results in the release of all of the latches  10 . 
     Once the latches  10  have been release, the bars  14  are locked in the release position by a locking mechanism generally indicated at  68  in FIG.  5 . Each locking mechanism  68  includes a lever  69  (FIGS. 1 and 5) mounted on the end of each bar  14  opposite to the end carrying the lever  26 . The lever  69  is mounted on one end of a shaft  70 , which is rotatably mounted in one end  71  of the compartment  20  and in an L-shaped bracket  73 . An arm  74  is mounted on the inner end  75  of the shaft  70  for rotation therewith. The arm  74  is guided between the panel latched and release positions by a pin  77  extending inwardly from the bracket  73  into an arcuate slot  78  in the arm. The arm  74  and consequently the lever  69  are releasably retained in the panel latched position by a detent pin  80 , which extends into a shallow conical depression  81  in the bracket  73 . The pin  80  extends outwardly from a cylindrical barrel  81  mounted in the end of the arm  74  opposite to the end  75  receiving the shaft  70 . A helical spring  83  bears against the head  84  of the pin  80  for biasing the outer end thereof into the depression  81 . When the bar  14  is rotated from the panel latching position (shown in solid lines in FIG. 5) to the panel release position (shown in phantom outline in FIG. 5) the arm  74  is also rotated. The pin  80  escapes from the depression  81  and is rotated with the arm  74  to the panel release position in which the pin  80  encounters a hole  86  extending through the bracket  73  and the end  71  of the compartment  20 . Thus, the arm  74  and consequently the lever  69  and the bar  14  are locked in the panel release position. 
     Referring to FIGS. 2 and 3, a plurality of ejectors  88  are provided on the interior of the frame  4 . The ejectors  88  are spring loaded plungers for biasing the panel  8  outwardly from the frame  4 . Immediately following release of the panel  8  by the latches  10 , the ejectors  88  push the panel  8  outwardly to clear the opening  6 . 
     In operation, one or more bars of the actuation mechanism is pulled towards the operator and away from the limit positions defined by the detent pin  80 , the depression  81  and the hole  86 . Rotation of a bar  14  causes pivoting of a lever  26  on one end of the bar  14 , and consequently rotation of the shafts  31  and  29 , and the pinion  40 . Rotation of the pinion  40  results in movement of the rack  42  and the cable  45  which translates into rotation of all of the levers  54  to release the latches  10 . The panel  8  is thus free to move and is pushed out of the frame  4  by the ejectors  88 . 
     An auxiliary actuator generally indicated at  89  (FIGS. 2 and 3) for the panel  8  includes a pulley  90  rotatably mounted in one corner of the frame  4 . A notch in the pulley  90  engages a pin  91 , which is attached to the cable  45 . The auxiliary actuator can override the release mechanism  12 . The pulley  90  is rotated by either of two levers defined by handles  94  (one shown—FIG. 1) mounted on the ends of a shaft carrying the pulley. The handles  94  are located on the interior and exterior lower corners of the frame  4  (i.e. inside and outside the window). Rotation of either handle  94  results in simultaneous release of all latches  10 . 
     With reference to FIG. 1, a preferred form of panel  8  includes a sash  96  carrying a panel, which is sealed in the sash  96  by a rubber molding  98 . The panel  8  can be removed from the sash  96  by removing the molding  98 . 
     Once removed, the panel  8  can be re-installed in the opening  6  by pushing the panel as far as possible into the opening to compress the plungers of the ejectors  88 . The detent pins  80  are pushed out of the holes  86 , and the bars  14  are rotated to return the pins  80  to the latched position in the recesses  81 . The panel  8  is secured in the opening  6  by rotating either one of the handles  94  to return the latches  10  to locked position. 
     Referring to FIG. 6, the emergency lighting assembly  21  is used to illuminate the opening  6  and to provide an indication where the exit system is located and whether the panel  8  is latched or released. When the lighting is constant, the panel  8  is in the latched condition, and strobe lighting indicates that the panel  8  has been released. The lighting system  21  includes a plurality of high intensity light emitting diodes (LEDS)  100  in the bars  14  and on the auxiliary release  89 , a strobe switch  102  on the frame  4  to indicate when the panel  8  has been jettisoned, light actuation elements (not shown) and a power pack  103  external to the frame  4 . The power pack  103  is connected to the remainder of the lighting system by a cable  105 . The power pack  103  includes a microprocessor (not shown) for controlling the lighting system. 
     The light actuation elements include an immersion sensor, an impact sensor, a roll over sensor and a pilot operated on-off switch (none of which are shown). The sensors are mounted on the aircraft fuselage or incorporated in the power pack  103 . The immersion sensor is triggered when the aircraft is submerged in water, the impact sensor is triggered when a predetermined impact force has been exceeded, and the roll over sensor is triggered when the aircraft rolls over. The pilot switch is mounted on the console of the aircraft, permitting manual activation of the lighting system. All of the sensors and the switch are wired in parallel so that any one of them can be used to activate the emergency lighting system. 
     When the lighting system is activated, the LEDs  100  will be simultaneously activated to illuminate the release bars  14  and the handles  94 . The bars  14  and the handles  94  will remain illuminated until the system is deactivated, or until the panel  8  is released and jettisoned. The strobe mode is activated by one of the spring loaded ejectors  88  which closes the strobe switch  102 . Strobe lighting will continue as long as the panel  8  is free of the frame  4 . 
     A second embodiment of the emergency exit system for use in a door is illustrated in FIGS. 7 to  10 . The second embodiment of the system includes a frame  4  with an opening  6  therein which is closed by a panel  8  (in this case defining a door). The panel  8  includes a window  110 , and flanges  111  extending along the periphery thereof for sealing against the fuselage  112  (FIG. 9) of a helicopter in the closed position. 
     The panel  8  is mounted in the frame  4  by means of hinges  113 , which permit rotation of the panel  8  between the open and closed positions. The panel  8  is normally opened and closed using a handle  114  and latch pins  115  (FIG.  7 ), all of which are connected to the handle  14 . An actuating mechanism similar to the same mechanism in FIGS. 1 to  4  includes a plurality of independently operated bars  14  for initiating release of the door panel  8 . The bars  14  are connected to a release mechanism generally indicated at  12  (FIG. 8) housed in compartments  116  in the manner described above in connection with FIGS. 1 to  4 . In the embodiment of the invention, movement of one of the bars  14  to the release position causes actuation of the release mechanism, which includes the latches  117 . The release mechanism also releases the hinges  113  to release the panel  8  completely from the frame  4 . The latches  117  are interconnected by a cable  118  (FIG.  8 ), which extends around pulleys  119  at the bottom corners of the frame  4  and returns around the top end thereof, i.e. the cable  118  extends in two rows around the top and sides of the frame  4 . Grooved rollers  122  are provided in the frame  4  for guiding the cable  118  around the frame. 
     Each latch  117  is pivotally mounted on the frame  4  to secure the panel  8  in the opening  6 . An associated plunger  115  is mounted in the panel  8  adjacent the latch  117  to permit latching and unlatching of the door panel  8  during normal operation. More specifically, during normal operation, the door panel is latched by rotating the handle  114  (counterclockwise as shown in FIG. 7) to cause the plunger  115  to extend outwardly from the side of the panel into engagement with the latches  117 . Rollers  122  on the outer ends of the plunger  115  engage the inner sides of the latches  117  (FIGS. 7 and 9. By rotating the handle  114  in the opposite direction, the plungers  115  are retracted into the panel  8  to unlatch the panel permitting swinging of the door panel on the hinges  113  to the open position (FIG.  8 ). 
     As best shown in FIG. 8 each latch  117  includes an arm  123  connected to a pinion  124  (FIG. 8) rotatably mounted in the frame  4 . The pinion  124  meshes with a rack  125  mounted on the cable  118 . The rack  125  is engaged by a stop  127  (similar to the stops  50 ). When the cable  118  moves, the stop  127  moves the rack  125  to rotate the pinion  124  which in turn causes pivoting of the tab  123  through  45  to release the latch  115 . 
     Referring to FIGS. 10A and 10B, each hinge assembly  113  includes an arm  130  with holes therein for receiving bolts  131 . A narrow end  133  of the arm  130  is rotatable mounted on a pin defined by a bolt  134  in a clevis  136 . The bolt  134  is retained in the clevis  136  by nut  137 . The body  139  of the clevis  136  tapers to an annular groove  140  and a head  141 . The head  141  is inserted into the large end  143  of a keyhole slot  144  in a plate  145  mounted on the cable  120 . By moving the head  141  into the narrow end  146  of the slot  144 , the clevis  136  and the plate  130  are retained in engagement with the cable  120 . When the cable  120  moves (upwardly in FIG.  10 B), the clevis  136  and consequently the entire hinge is release. At the same time, the arms  123  of the latches  117  rotate  45  to release the plungers  115 , whereby the entire door panel  8  is released for jettisoning. 
     The second embodiment of the invention also includes an auxiliary release mechanism  89  similar to the same mechanism in the first embodiment of the invention.