EMERGENCY OXYGEN SUPPLY SYSTEM FOR PASSENGERS IN AIRCRAFT

Abstract: An oxygen generator of an emergency chemical oxygen generating system is mounted on a sliding mechanism that displaces the oxygen generator vertically and horizontally away from the walls of the oxygen generator container when the door of the module is opened, in order to reduce the heating of the container walls and the surrounding areas. The sliding mechanism can be a telescoping assembly having multiple sliding segments, a slot in the side of the module wall with a tab attached to the generator such that the tab slides within the slot allowing for downward sliding of the generator, or an arrangement of channels and rollers. The movement of the generator from a stowed position to a use position can also initiate the flow of oxygen.

Description: EMERGENCY OXYGEN SUPPLY SYSTEM FOR PASSENGERS IN AIRCRAFT BACKGROUND OF THE INVENTION Field of the Invention: This invention relates generally to passenger oxygen modules equipped with chemical oxygen generators, and more particularly concerns an oxygen generator mounting structure that permits the oxygen generator to be deployed to a safe position to improve heat dissipation from the chemical oxygen generator away from the chemical oxygen generator container and structures surrounding the oxygen container. Description of Related Art: Chemical oxygen generators are used in passenger aircraft as a source of oxygen for use by the cabin occupants to protect them from hypoxia in the event of a decompression or depressurization of the passenger cabin. However, the chemical reactions that release oxygen in such chemical oxygen generators are typically highly exothermic, producing a significant amount of heat when the generator is actuated during an emergency. Such heat can damage adjacent airplane structures, especially when those structures are made from lightweight aerospace composite materials. While such structures can be protected from the heat produced by a chemical oxygen generator by installation of thermal insulation, doing so increases the weight of the installed equipment, which is undesirable for use on airplanes. While insulation can also be achieved by installation of the chemical oxygen generator with a greater air space from the walls of the oxygen module, this approach unfortunately results in oxygen modules that occupy more space, decreasing useful cabin space. Chemical oxygen generating modules are commonly installed beneath the overhead luggage bins, so that if space is added to oxygen modules to facilitate heat management, the oxygen modules are thicker, and the clearance between the heads of the cabin occupants and the module is reduced, which is also undesirable for airlines. With reference to the prior art illustrated in Figs . 1 A and 1 B , one presently known conventional oxygen generator mounting system mounts an oxygen generator 10 on a pivoting arm 12 in an oxygen generator container 14, and pivots the oxygen generator to a lowered position 16 to improve heat dissipation when the oxygen generator container lid is opened to deploy an oxygen mask. As is shown in FIG. 1 A, when the pivoting type of oxygen generator is deployed at some angle θ , at any angle θ between 0° and 90°, the horizontal coordinate x of the generator is given by the expression: r cos (θ), and the vertical coordinate y is given by the expression: r sin (θ). However, for a pivoting movement of any given angle θ, the extent of displacement of the oxygen generator is limited by the length of the pivot arm, which is in turn limited by the dimensions of the oxygen module. Thus, while such a system enjoys the benefits of simplicity associated with a pivoting system, such a system imposes restraints on the packaging and deployment enveloper of emergency oxygen systems. It would be desirable to provide an emergency chemical oxygen generating system for passenger aircraft with a mounting mechanism that would allow the oxygen generator to reach a position that lies outside this limited envelope of positions that can be reached by use of a pivoting mounting system for the oxygen generator. The present invention meets these needs. SUMMARY OF THE INVENTION Briefly, and in general terms, the present invention provides for an emergency chemical oxygen generating system for passenger aircraft in which the oxygen generator is mounted on a structure that permits the oxygen generator to be displaced vertically and horizontally away from the walls of the container for the oxygen generator when the door of the module is opened, in order to reduce the heating of the container walls, the air gap surrounding the container walls, and the surrounding structures behind the oxygen container. By causing the generator to translate downward and sideways, the choice of positions in which the generator comes to rest can be selected over a wider range of possibilities than if a pivoting repositioning mechanism is employed. The use of a sliding mounting mechanism allows the generator to reach a position outside the envelope of positions that can be reached by use of a pivoting mounting mechanism. The horizontal and vertical displacements are defined by the angle at which the sliding mounting mechanism is installed, and by the extent of the sliding displacement accomplished by the sliding mounting mechanism. The invention accordingly provides for an emergency oxygen supply system utilizing a sliding mechanism for mounting of a chemical oxygen generator. The sliding mechanism advantageously slides and may also pivot, for moving the chemical oxygen generator away from the walls of an oxygen module during operation of the generator. Such a capability enhances the ability to avoid heat damage to the oxygen module from the generator and improves the space utilization of the module within the passenger compartment. In one presently preferred embodiment, the sliding mechanism comprises a telescoping assembly having one end secured to the container and the other end secured to the generator, and having multiple sliding segments producing a total sliding displacement (L) that results in a greater horizontal or vertical displacement than can be accommodated by a pivoting means having dimensions to fit into the confines of the oxygen module. In an alternate embodiment, the sliding mechanism comprises a slot in the side of the module wall, with a tab attached to the generator, such that the tab slides within the slot, allowing for downward sliding of the generator. In another alternate embodiment, the sliding mechanism can comprise an arrangement of channels and rollers analogous to those used to permit a file drawer to be moved from a stored position to a position in which the drawer's contents can readily be accessed. In another aspect of the invention, the movement of the generator from a stowed position to a use position can also initiate the flow of oxygen. For example, the actuation pin of the oxygen generator can be attached to one end of a short lanyard, while the other end of the lanyard can be attached to the module structure, so that when the oxygen generator slides downwardly in relation to the oxygen module structure, the lanyard will withdraw the actuation pin, initiating oxygen flow. These and other aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings, which illustrate by way of example the features of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 A is a schematic diagram of a prior art pivoting generator in a stowed position; Fig. IB is a schematic diagram of the prior art pivoting generator of Fig. 1 A in a deployed position; Fig. 2A is a schematic diagram of a sliding generator according to the principles of the invention in a stowed position; Fig. 2B is a schematic diagram of the sliding generator of Fig. 2A in a deployed position; Fig. 3 is a cross-sectional view of a first embodiment of a telescoping sliding generator according to the invention mounted in an oxygen module showing deployment of the oxygen generator; Fig.4A is a cross-sectional view of a second embodiment of a telescoping sliding generator according to the invention mounted in an oxygen module in a stowed position; Fig. 4B is a cross-sectional view of the sliding telescoping generator of Fig. 4A in an intermediate position; Fig 4C is a cross-sectional view of the sliding telescoping generator of Fig. 4A in a lowered position; Fig. 5A is a cross-sectional view of a third embodiment of a sliding oxygen generator in a stowed position; Fig. 5B is a cross-sectional view of the sliding oxygen generator of Fig. 5 A in an open position; Fig. 6A is a cross-sectional view of a fourth embodiment of a sliding oxygen generator in a stowed position; Fig. 6B is a cross-sectional view of the sliding oxygen generator of Fig. 6 A in an open position; and Fig. 7 is an enlarged partial sectional view of a release mechanism for an actuation pin of the ignition assembly of an oxygen generator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Chemical oxygen generators used in passenger aircraft produce heat that can damage adjacent airplane structures. Those structures canbe insulated by thermal insulation or by an air space, but the use of insulation results in increased weight, and the provision of an insulating air space results in a decrease of useful cabin space. While mounting the oxygen generator to pivot to a lowered position when deployed can improve heat dissipation, the extent of useful displacement of the oxygen generator is limited by the length of the pivot arm and the dimensions of the oxygen module. The present invention addresses these issues while remaining capable of economical manufacture and servicing, and reliable operation. As is illustrated in the drawings, the invention is embodied in an emergency oxygen supply system having a sliding mounting mechanism for mounting a chemical oxygen generator, to allow the oxygen generator to slide and pivot, for vertical and horizontal displacement of the chemical oxygen generator away from the walls of an oxygen module during operation of the generator. With reference to Figs. 2 A and 2B, an emergency chemical oxygen generator system 20 according to the invention includes an oxygen generator 22 and a sliding assembly 24 mounted in the oxygen generator container 26, for sliding at an angle θ to a lowered position 28. As is illustrated in Figs. 2A and 2B, the horizontal coordinate x for the sliding generator is given by the expression L cos (θ), and the vertical coordinate y is given by the expression L sin (θ). Referring to Fig. 3, in a presently preferred embodiment, the oxygen module container 30 includes a lid 32 shown in an open position. The oxygen generator 34 is mounted by a sliding mechanism 36 in the container for sliding movement at an angle θ to a lower horizontally and vertically displaced position. In this first preferred embodiment, the sliding mechanism comprises a telescoping assembly having one end 38 secured to the container and the other end 40 secured to the generator, with multiple sliding segments 42 producing a total sliding displace¬ ment L. Referring to Figs. 4A, 4B and 4C, in a presently preferred embodiment, the oxygen module container 30' includes a lid 32' shown in a stowed or closed position in Fig.4A. The oxygen generator 34' is mounted by a sliding mechanism 36' in the container for sliding movement to a lower horizontally and vertically displaced position. In this second preferred embodiment, the sliding mechanism comprises a telescoping assembly having one end 38' secured to the container and the other end 40' secured to the generator, with multiple sliding segments 42' producing a total sliding displacement as shown in Fig. 4C. The telescoping assembly 36' can be connected to the container by a pivot pin 44, and can be supported by a retractable pin 46 that can be retracted when the lid opens and the oxygen generator is to be activated, allowing the telescoping assembly to pivot and slide the oxygen generator to a lower intermediate position with the telescoping assembly resting on a lower stop 48, as is shown in Fig. 4B. When the telescoping assembly reaches the lower position of Fig. 4B, the telescoping assembly segments can fully extend to allow the oxygen generator to slide to the fully lowered horizontally and vertically displaced position shown in Fig.4C . Alternatively, instead of supporting the telescoping assembly by a retractable pin, the oxygen generator can be supported by other similar means, or by the oxygen module container lid in its closed position, so that the oxygen container and telescoping assembly can be released to slide to the intermediate and lowered positions by opening of the lid. With reference to Figs. 5 A and 5B, in a second preferred embodiment, an oxygen module 50 having a lid 52, shown in the closed position in Fig. 5A, includes an oxygen generator 54 mounted by a sliding mechanism 56 in the container for sliding movement to a lower horizontally and vertically displaced position. In this embodiment, the sliding mechanism comprises a slot 58 in the side of the module container wall, with a tab 60 attached to the generator, such that the tab slides within the slot, allowing for downward sliding of the generator, producing a total sliding displacement shown in Fig. 5B. Alternatively, instead of supporting the oxygen generator by a retractable pin, the oxygen generator can be supported in the upper position by the oxygen module lid in its closed position, so that the oxygen generator can be released to slide to the lowered position by opening of the lid. As is illustrated in Figs. 6 A and 6B, in a third preferred embodiment, an oxygen module container 70 has a lid 72, shown in a closed position in Fig. 6A. An oxygen generator 74 is mounted in the container by a sliding mechanism 76 to lower the oxygen generator horizontally and vertically. In this embodiment, the sliding mechanism can comprise an arrangement of channels and rollers analogous to those used to permit a file drawer to be moved from a stored position to an open position. The oxygen generator can thus be connected on each side by a bracket 78 between a pair of rollers 80 journalled in a sliding channel member 82 on each side of the oxygen module container. The channel member is in turn mounted on a pair of rollers 84 mounted on each side of the oxygen module container at a downwardly directed angle, and can be retained in this position by a retractable pin 86, disposed in the oxygen module container at the lower end of the channel member. The retractable pin can be retracted when the lid opens, and the oxygen generator is to be activated, allowing the sliding roller assembly and oxygen generator to slide at a lower horizontally and vertically displaced position. Alternatively, instead of supporting the roller assembly and oxygen generator by a retractable pin, the roller assembly and oxygen generator can be supported by the lid in its close position, so that the oxygen generator can be released to slide to the lower position by opening of the lid. In another aspect of the invention, the movement of the generator from a stowed position to a use position can also initiate the flow of oxygen, as is shown in Fig. 7. The oxygen generator 90 typically has an actuation pin 92 disposed in the actuator pin sleeve 94 of the oxygen generator. A coil spring 96 supported in the actuation pin sleeve presses against the end piece 98 of the actuation pin and biases the actuation pin toward the percussion primer 100. The actuation pin can be secured from striking the percussion primer by a locking pin 102 extending through an aperture in the actuation pin. The locking pin of the oxygen generator, for example, can be attached to one end of a short lanyard 104, while the other end of the lanyard (not shown) can be attached to the module structure, so that when the oxygen generator slides downwardly in relation to the oxygen module structure, the lanyard will withdraw the locking pin from the actuation pin to strike the percussion primer, initiating oxygen flow. -l i¬ lt will be apparent from the foregoing that while particular forms of the invention have been illustrated and described, various modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims.

Claims: WHAT IS CLAIMED IS: 1. An emergency oxygen supply system for passengers in aircraft, comprising: an oxygen module container; an oxygen generator; and a sliding assembly in the oxygen module container for mounting said oxygen generator, said sliding assembly providing said oxygen generator with a first position disposed in said oxygen module container and for moving said oxygen generator by a sliding movement to a second position displaced lower relative to said first position. 2. The emergency oxygen supply system of Claim 1 , wherein said sliding assembly comprises a telescoping assembly having one end secured to the container and the other end secured to the oxygen generator to provide for sliding movement of said oxygen generator. 3. The emergency oxygen supply system of Claim 2, wherein said telescoping assembly comprises multiple sliding segments. 4. The emergency oxygen supply system of Claim 1 , wherein said sliding assembly comprises a telescoping assembly having one end secured to the container and the other end secured to the oxygen generator to provide for pivoting and sliding movement of said oxygen generator. 5. The emergency oxygen supply system of Claim 1 , wherein said sliding assembly comprises a slot in the side of the module wall, with a tab attached to the generator, such that the tab slides within the slot, allowing for downward sliding of the generator. 6. The emergency oxygen supply system of Claim 1, wherein said the sliding assembly comprises an assembly of channel members and rollers. 7. The emergency oxygen supply system of Claim 1 , further comprising means for initiating the flow of oxygen from said oxygen generator when said oxygen generator moves from said first position to said second position. 8. The emergency oxygen supply system of Claim 7, wherein said oxygen generator comprises an actuation pin and an percussion primer, said actuation pin being biased toward striking the percussion primer, and said actuation pin being secured from striking the percussion primer by a locking pin, said locking pin being connected to said oxygen module container, such that when the oxygen generator slides downwardly in relation to the oxygen module container, the locking pin will release the actuation pin to strike the percussion primer, initiating oxygen flow. 9. An emergency oxygen supply system for passengers in aircraft, comprising: an oxygen module container; an oxygen generator; and a sliding assembly to displace the oxygen generator on a predetermined path downward and away from said oxygen module container. 10. The emergency oxygen supply system of Claim 9, further comprising: a pivoting member hinged to said container to allow said sliding assembly to rotatably move downward from said container. 11. The oxygen supply system of Claim 10, further comprising means for initiating a flow of oxygen from said oxygen generator upon said generator being deployed from said container. 12. The emergency oxygen supply system of Claim 11, wherein said oxygen generator comprises an actuation pin and a percussion primer, said actuation pin being biased toward striking the percussion primer, and said actuation pin being secured from striking the percussion primer by a locking pin, said locking pin being connected to said oxygen module container, such that when the oxygen generator slides downwardly in relation to the oxygen module container, the locking pin will release the actuation pin to strike the percussion primer, initiating oxygen flow.

Inventors: CANNON JAMES C, CANNON, JAMES, C.
Applicants: BE AEROSPACE INC, B/E AEROSPACE, INC.
Application year: 1999
Main classification: A62B25
IPC codes: A62B25, B64D10