GB731329A - Improvements in and relating to the buckets of axial-flow machines of the turbine and compressor kind - Google Patents

Abstract

731,329. Turbine and compressor blades. GENERAL ELECTRIC CO. June 29, 1953 [July 9, 1952], No. 17954/53. Class 110 (3). In a machine such as an axial-flow turbine or a compressor, a blade root portion comprises a plurality of axially-spaced fingers which engage circumferential grooves formed in the rim of the rotor, at least one dowel-pin passing through co-operating holes formed in the fingers and in the tongues formed by the circumferential grooves in the rotor run. The fingers on the root portion comprise a first set which include a pair of side fingers, and a second set comprising at least one intermediate finger disposed between the side fingers and circumferentially displaced relative to the side fingers by a distance equal to half the circumferential thickness of the blade root. The dowel pin is located substantially at the middle of one of the sets of fingers while other portions of the dowel are disposed in circular recesses formed half in one finger of the other set and half in the corresponding abutting finger of the next adjacent blade. In the embodiment described, the blade root is channel-shaped in plan view and is formed with four intermediate fingers 2b, 2c, 2d, 2e, the axial thickness of which is reduced in steps towards the radially inner end of the blade the side flanges 2a, 2f are offset in the circumferential direction. Three dowel pins 4a, 4b, 4c pass through bores formed in the fingers on the blade root and the tongues on the rotor. The small side flanges 3a, 3b prevent axial deflection of the end tongues 1a, 1g of the rotor. The two intermediate fingers 2b, 2e are of trapezoidal section in plan view whereas the fingers 2c, 2d are of rectangular section.