Patent Application
20080149804
The present invention relates to seat track assemblies for passenger aircraft. More particularly, the present invention relates to a seat track assembly which is lightweight and has an optimum load bearing configuration.
Seat tracks are used in passenger aircraft to anchor passenger seats to the airframe of the aircraft. Conventional seat tracks typically have a “hat” design (a pair of outwardly-extending top flanges and a pair of outwardly-extending middle flanges which together form a top cord and a pair of outwardly-extending bottom flanges which form a bottom cord). The middle flanges are used to attach the track to the airframe.
Seat tracks are used in Passenger Aircraft to attach seats and interior furnishings (e.g. Lavs, galleys, closets). Conventional seat tracks typically have higher internal loads between supports so it is usually advantageous that the track be designed with minimum height at the supports and increased height between supports. Typical extrusion processes for seat track design usually prevent consideration of variable height designs due to the cost of the excess material and its removal. In addition, conventional seat tracks typically are designed as an open I or Pi cross section. These open sections are subject to instability related failures and usually require excess material to react these instability loads.
One of the limitations of the conventional aircraft seat tracks is that the top, middle and bottom flanges are thick to overcome load instability. Moreover, seat tracks are typically extruded. Extrusion is optimal for objects which have a constant or uniform cross-sectional geometry; because an optimized seat track would be thicker at the middle than at the ends of the track since loads are greater at the middle, fabrication of an optimized extruded track would require extensive machining of a large block of metal such as titanium.
The present invention is generally directed to a seat track assembly. An illustrative embodiment of the seat track assembly includes a seat track having an elongated track plate and a pair of generally elongated, parallel, spaced-apart track flanges extending from the track plate. Each of the track flanges is variable in depth. The term Pi-Box is derived from the Greek letter pi and the lower plate attached creating a closed box. This invention reduces weight by allowing variable height geometry and using an enclosed section. Variable height allows optimization of the cross section height to match internal loads, and the box section reduces instability created by thin gauge materials. A method of fabricating a seat track assembly is also disclosed.
The present invention is further generally directed to a method of fabricating a seat track assembly. An illustrative embodiment of the method includes providing a seat track having an elongated track plate and a pair of generally elongated, parallel, spaced-apart track flanges extending from the track plate, wherein each of the track flanges is variable in depth; and welding a base flange to the track flanges of the seat track.
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Referring to the drawings, an illustrative embodiment of the seat track assembly is generally indicated by reference numeral 1. The seat track assembly 1 includes a generally elongated base flange 2 which is typically titanium. In some embodiments, the base flange 2 is a constant gauge base flange 2; in other embodiments, the base flange 2 is a variable gauge base flange 2. The base flange 2 includes a generally elongated, curved center segment 3. A generally straight end segment 4 terminates each end of the center segment 3. In some embodiments, multiple lightening apertures 5 are provided in the center segment 3 in adjacent, spaced-apart relationship with respect to each other. Each lightening aperture 5 typically has a generally elongated, rectangular shape.
A Pi-Box type seat track 10 is provided on the base flange 2. The seat track 10 is typically titanium and includes a generally elongated, rectangular track plate 11. In some embodiments, the seat track 10 is extruded; in other embodiments, the seat track 10 is machined from a block of metal such as titanium. The track plate 11 has a pair of opposite edge portions 12. As shown in
A pair of elongated track flanges 16 extends from the track plate 11 of the seat track 10 in generally parallel, spaced-apart relationship with respect to each other. Each of the track flanges 16 is welded and/or otherwise attached to the base flange 2. As shown in
As shown in
Although this invention has been described with respect to certain exemplary embodiments, it is to be understood that the specific embodiments are for purposes of illustration and not limitation, as other variations will occur to those of ordinary skill in the art.
