Patent Application
20070057128
The present invention relates to a case flange on an auxiliary power unit and, more particularly, to an adapter that serves as an interface between the case flange and a support structure for the auxiliary power unit.
Auxiliary power units (“APU”) are used in aircraft to provide electrical power and compressed air to various aircraft systems during both ground and in flight operations. For example, when an aircraft is on the ground, the APU may provide electrical power to the electrical system, and compressed air to the environmental control systems, air drive hydraulic pumps, and starting air for the main engines.
Typically, an APU is located in the aft section of the aircraft, at or near the tailcone section. The APU may be mounted within the tailcone section via struts that extend between the APU and airframe structure within the tailcone. In many cases, a strut adapter may be used to couple the struts to an APU attachment interface, such as a gearbox pad. To meet weight restrictions, the APU attachment interface, and various other parts of the APU are typically constructed from lightweight materials, such as aluminum.
Recently, regulatory authorities have implemented regulations related to improved fire-resistance. To implement these new regulations, many aircraft may need to include more fire-resistant parts. Consequently, various solutions have been proposed to reconfigure various sections of the aircraft, including the above-identified APU mount structure. One of the proposed solutions includes shielding the APU attachment interface with a fireproof material and changing the material from which the APU attachment interface is constructed. However, because the fireproof material typically weighs more than previously used lightweight material, the overall weight of the aircraft may undesirably increase. Additionally, the material change or addition of material may increase the cost of manufacturing the aircraft.
Thus, there is a need for an APU mount system that is fireproof. Additionally, it is desirable for the system to be lightweight. Moreover, it is desirable for the system to be relatively inexpensive to implement.
The present invention provides a mount adapter configured to couple a case flange of an auxiliary power unit to a stud adapter, the case flange having a plurality of spaced apart fastener openings formed therethrough. The mount adapter comprises a first rib and a mount plate. The first rib has a portion configured to extend substantially parallel to at least a portion of the case flange and includes a plurality of openings formed therethrough. The openings are disposed in a pattern such that at least selected ones correspond to one or more of the case flange fastener openings. The mount plate has a first side integrally formed on the first rib, a second side, and a plurality of apertures extending therebetween. The first rib and the mount plate comprise fireproof material.
In one embodiment, and by way of example only, the mount adapter includes a first and a second rib and a mount plate. The first rib is configured to extend substantially parallel to at least a portion of the case flange, and includes a plurality of openings formed therethrough and disposed in a pattern such that at least selected ones correspond to one or more of the case flange fastener openings. The second rib is disposed substantially parallel to the first rib, and includes a plurality of openings formed therethrough and disposed in a pattern such that at least selected ones correspond to one or more of the case flange fastener openings. The mount plate is disposed between and integrally formed with the first rib and the second rib, and has a first side, a second side, and a plurality of apertures extending therebetween. The first rib, the second rib, and the mount plate comprise fireproof material.
In still another embodiment, and by way of example only, a mount system is provided for coupling a strut and an auxiliary power unit, where the auxiliary power unit includes a case flange having a plurality of spaced apart fastener openings formed therethrough. The system comprises a finger adapter, a mount adapter, and a stud adapter. The finger adapter has a first section and a second section, where the first section is configured to couple to the strut. The mount adapter is coupled to the finger adapter second section and comprises a first rib and a mount plate. The first rib is configured to extend substantially parallel to at least a portion of the case flange, and includes a plurality of openings formed therethrough and disposed in a pattern such that at least selected ones correspond to one or more of the case flange fastener openings. The mount plate has a first side integrally formed on the first rib, a second side, and a plurality of apertures extending therebetween. The first rib and the mount plate comprise fireproof material. The stud adapter is disposed between the finger adapter and the mount adapter.
Other independent features and advantages of the preferred mount system will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.
With reference now to
An isometric view of the APU 100 and the APU mount system 106 are provided in
The APU mount system 106 is coupled to at least one of the case flanges 128, 130 and includes a finger mount adapter 137, a stud adapter 138, and a case mount adapter 140. The finger mount adapter 137 is configured to receive and retain ends of the struts 108 and may have any one of numerous conventionally used configurations. The stud adapter 138 is coupled between the finger mount adapter 137 and case mount adapter 140, and may additionally have any one of numerous conventionally used configurations.
The case mount adapter 140 is preferably a unitary component including at least one rib 142 and a mount plate 144 that are integrally formed with each other. The rib 142 is configured to mate with a case flange 128, and at least a portion of the rib 142 extends parallel thereto. Although described herein as being mounted to a particular case flange 128, it will be appreciated that the rib 142 may alternatively be configured to mount to other case flanges 130, 132, 134 instead. Additionally, the rib 142 includes a plurality of openings 146 that are disposed in a pattern such that at least selected ones correspond with one of the case flange fastener openings.
The mount plate 144 interfaces with the stud adapter 138 and therefore, may have any one of numerous suitable configurations. In one exemplary embodiment, and as shown in
Returning to
The plurality of apertures 150 may extend between the plate first and second sides 147, 148, and each aperture 150 is appropriately sized and configured to receive a threaded fastener to fasten the stud adapter 138 to the mount plate 144. Preferably, the plurality of apertures 150 is disposed in a pattern such that each is collocated with an aperture on the stud adapter 138. A bearing hole 152 is formed substantially in the middle of the mount plate 144 to mate with a portion of the stud adapter 138.
In another exemplary embodiment of the mount adapter 140, as shown in
The second rib 154 extends substantially parallel to the first rib 142, and is suitably spaced apart therefrom to define a space 155 in which the case flanges 128, 130 may fit. Preferably, the ribs 142, 154 are spaced such that a close tolerance fit is provided when the case flanges 128, 130 are disposed therebetween. To provide sufficient strength for the mount adapter 140 when coupled to the strut 108, the ribs 142, 154 are preferably substantially similar in length.
Similar to the first rib 142, the second rib 154 includes a plurality of openings 158 that are disposed in a pattern such that at least selected ones correspond with one of the case flange fastener openings. Preferably, however, the second rib openings 158 are sized larger than the first rib openings 146. In one exemplary embodiment, the second rib openings 158 have a diameter suitable to retain plain bushings 160. The bushings 160 may be used for installing the fasteners 136 in the case flanges 128, 130 and for clamping the case flanges 128, 130 to each other.
With reference to
The hoist tabs 156 preferably extend radially away from the second rib 154 and substantially perpendicular from the mount plate 144. It will be appreciated, however, that the hoist tabs 156 may be formed in any other sections of the rib 154 and, in other embodiments, may not be coupled to the mount plate 144. Preferably, the hoist tabs 156 include openings 164 that facilitate installation and removal of the APU 100 from the aircraft 104.
A fireproof mounting system has now been provided that is relatively lightweight and easy to install. The system can be configured to be installed on any conventional APU case flange and thus, may be retrofitted into any aircraft.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
