Patent Application
20150144201
The subject matter disclosed herein relates to engine inlets, more specifically, to installation of engine inlet ducts and/or cowling.
Engines for, for example, aircraft such as helicopters or other rotorcraft utilize engine inlet ducting to direct airflow into the compressor of the engine. Some systems, for example, single engine systems, utilize a bifurcated inlet duct, which takes two airflow streams and directs them to the compressor inlet. In such ducts, fastening of the two duct legs to each other is required both inside and outside of the duct to ensure a proper seal and prevent leakage into the duct.
Typically, the inside of the annulus is accessible, so that a traditional bolted flange joint between the two duct halves, can be tightened via traditional tools, such as wrenches, to install the inlet duct. In particular systems, however, a position of engine components, such as an engine shaft, prevents access via hands or traditional tools to the fastening locations necessary to provide the desired seal between the two duct halves.
In one embodiment, a method of securing two components to each other includes locating a mounting strip at a first mounting flange of a first component. The mounting strip is slidably affixed to the first component and includes a plurality of strip openings and a tightening ramp located at each strip opening of the plurality of strip openings. A second component is located such that a second mounting flange of the second component abuts the first mounting flange. A plurality of pre-set fasteners are located at the second mounting flange. A fastener of the plurality of fasteners extends through each strip opening of the plurality of strip openings. The mounting strip is slid in a direction to increase tension on the plurality of fasteners via an increasing height of the tightening ramp under a fastener head of the fastener, thereby securing the first mounting flange to the second mounting flange.
In another embodiment, an inlet duct assembly includes a first inlet duct leg. The first inlet duct leg includes a first mounting flange and a fastener extending from the first mounting flange. The fastener has a fastener head located at a selected distance from the mounting flange. A second duct leg includes a second mounting flange configured to abut the first mounting flange and a slidably located mounting strip having a strip opening. The fastener extends therethrough. The mounting strip includes a tightening ramp having an increasing height in one direction. Sliding the mounting strip along the second mounting flange increases a tension on the fastener and thus secures the first mounting flange to the second mounting flange.
In yet another embodiment, a method of installing an inlet duct assembly to a rotary winged aircraft includes locating a first inlet duct leg at an engine inlet of a rotary winged aircraft. The first inlet duct leg includes a first mounting flange and a fastener extending from the first mounting flange. The fastener has a fastener head disposed at a preselected distance from the mounting flange. A second inlet duct leg is located at the engine inlet such that a second mounting flange of the second inlet duct leg abuts the first mounting flange. The second inlet duct leg includes a slidably located mounting strip having a strip opening, the fastener extending therethrough, and a tightening ramp having an increasing height in one direction. The mounting strip is slid to increase tension on the fastener thereby securing the second mounting flange to the first mounting flange.
In still yet another embodiment, a method of installing an inlet duct assembly to a rotary winged aircraft includes locating a first inlet duct leg at an engine inlet of a rotary winged aircraft. The first inlet duct leg includes a first mounting flange and one or more fasteners extending from the first mounting flange. The fastener head(s) disposed at a preselected distance from the mounting flange. A second inlet duct leg is located at the engine inlet such that a second mounting flange of the second inlet duct leg abuts the first mounting flange. The second inlet duct leg includes a fixed mounting strip attached to the flange, having a strip opening, the fastener extending therethrough, and a tightening ramp having an increasing height in one direction. The insertion of the fastener of the first inlet leg into the lower ramp portion of the fixed mounting strip on the second inlet half, then, when the two inlet legs are moved relative to one another into final position, the fastener head is slid up the ramp to increase tension on the fastener thereby securing the second mounting flange to the first mounting flange.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
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Due to the location of the mount shaft 32 and the shape of the inlet duct 24, typical methods used to secure the duct legs 34 to each other are unable to be used, as the area between the duct legs 34, as well as an interior of the inlet duct 24 is inaccessible with conventional tools.
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In an alternate embodiment, the mounting strip 54 is affixed to the flange of the second mounting flange. In such manner that when the fastener heads 48 are inserted into the strip openings 58, the flanges of the two inlet halves can be moved relative to one another axially in which the height of the tightening ramps 60 under the fastener heads increase, in turn increasing the tension on the fasteners 44 drawing the second mounting flange 42b toward the first mounting flange 42a as in the above.
The structure and method described herein provides for remote fastening between two components via the sliding mounting strip 54 relative to fasteners 44 through the use of the axially directed tightening bolt 66 to cause movement of the mounting strip 54. While described herein relative to engine inlet ducts, it is to be appreciated that the structure and method described would be useful in other applications, such as fastening components of cowlings or fairings to one another.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
