GB334405A - Improvements in or connected with frame structures particularly suitable in aircraft construction - Google Patents

Abstract

334,405. Wallis, B. N. Sept. 26, 1929. Framework; fuselages; planes, construction of. - Frame structures for wings and fuselages comprise longitudinal members composed of thin tubular members arranged in bays some or all of which are non- rectangular; each tubular member terminates in a strengthening sleeve adapted to connect the tubular member in one bay to the continuing tubular member of the adjacent bay, the sleeve being formed with terminal flanges, all the opposed flanges at the end of each bay being contained in a single plane transverse to the structure and being clamped together. Lateral members have their ends connected to and located by the flanges and each joint is so arranged that the forces in the longitudinal and lateral members are all directed to a common point of intersection between the flanges. In a fuselage or wing structure comprising upper and lower pairs of spaced longitudinals connected by lateral members dividing the structure into bays of irregular shape, longitudinal tubular members 1, Fig. 4, which may be formed from helically-wound tubular strips, have sleeves 2 at each end formed with flanges 3, the outer surfaces of which subtend predetermined angles to the axis of the tubes so that these can extend at any desired angle relatively to each other. Lateral members 4 may be clamped between the flanges 3 or, as shown, be provided with bifurcated end fittings 13 clamped to the flanges 3 by one of the bolts 12 securing the flanges to each other. Diagonal bracing-members 5 pass through holes 9, 10 in sleeve and tube respectively, and are attached by internal cups 14 formed with coned surfaces 15 bearing on similar surfaces 16 on the flanges. In a modified form, Fig. 5, the sleeves 2 have internal flanges 18 threaded internally at 19, the threads of adjacent flanges being left and right handed respectively. These are clamped together by an externally-threaded ferrule 20, Fig. 8, upon which is mounted a key-plate 23, Fig. 9. A bearing- plate 26 is clamped between the key-plate and a flange 18 on assembly and serves for the connection of lateral members. Cups 31 for receiving diagonal bracing members 33 are threaded externally to opposite hands to engage with internal screw-threads 29, 30 on the ferrule 20. The screw-threads 19 in the sleeves are normal to the flanges 18, which may in addition be extended outwardly. The bearing-plate 26 may be omitted and lateral members be attached to the key-plate. The bearing-plates and lateral members may be employed for connection of other framing members such as those for supporting engine or petrol tank and the internal cups may serve also for attachment of stavs for these members. Alternatively, the cups may be omitted and diagonal members be attached to external flanges on the sleeves. A wing spar is illustrated built up from longitudinal built-up tubular booms having square transverse panels comprising vertical, and cruciform diagonal, struts, and diagonal bracing members between the transverse panels; the outer bays of the spar are shown as tapering to the wing tips and embody tubular members of progressively reduced diameter. According to the first Provisional Specification, transverse frames of apertured and corrugated metal sheet mav be secured at their borders to the flanges of the strengthening sleeves. According to the second Provisional Specification, in a wing having tubular open members, ribs or formers of angle or T-section may be attached to the key-plates 23 by means of bearers disposed on opposite sides of the plate and projecting beyond it to receive the inturned flange of the rib between them.