Improvements in or relating to blade structures for axial flow compressors, turbinesor the like

702,549. Turbine and compressor blades. BRISTOL AEROPLANE CO., Ltd. April 21 1952 [April 20, 1951], No. 9315/51. Class 110 (3) An axial-flow turbine or compressor blade comprises a blade working portion and a hollow sheet metal root portion extending therefrom, the root portion having a pair of opposite divergent sides with one or more stiffening members extending therebetween to prevent lateral movement of the sides. The blade working portion may be hollow and of sheet metal, the divergent sides of the root portion being made integral therewith. In Figs. I and II, the blade root portion comprises a platform 4 having divergent sides 7, 8 which are connected by a stiffening member 9, the flanges 10, 11 of which are connected to the inner faces of the sides 7, 8. The blade working portion extends through the platform 4 and stiffener 9 and the remaining sides 5, 6 and blade are cut away at 13, 12 for lightening purposes or to allow the passage of cooling or heating fluid. The blade root portions may be accommodated in axial, circumferential or oblique slots. In Fig. III, the rotor blades 24 pass through a. ring 18 comprising a frustoconical surface 19, having divergent sides 20, 21 which are connected by a sheet metal stiffening ring 23 having upward-turned flanges 26, 27. Down-turned lugs 31, 32 also extend from the ring 25 and correspond to lugs extending from the sides 20, 21, and U-shaped stiffeners 33 extend therebetween. Bolts 30 secure the blades between the rotor discs 28, 29 In Fig. VI the root portion comprising the divergent sides 35, 36 is formed integral with the blades and the ends of the roots are closed either by integrally pressed-out parts or by additional parts brazed in position, these parts constituting the stiffening members. Tray-like distance pieces 37 having sides 38, 39 contiguous with the sides of the roots 36, 35 ate disposed between the blade roots. A platform ring member 18 with downward-turned side flanges surrounds the root portions and distance pieces.