Patent GB-1179009-A (GB)
Title: Improvements in Gas Turbine Jet Engine Support Structure
Inventor: HOWALD WERNER ERNST
IPC: F02C7/20
Filed: 1967-10-30
Abstract: 1,179,009. Gas turbine jet engines - exhaust cone mounting. GENERAL ELECTRIC CO. Oct.30, 1967, No.49190/67. Headings F1G and F1J. The invention relates to means for supporting an inner member within the exhaust duct of a gas turbine engine, the inner member being supported from the outer casing by a plurality of pairs of struts, the struts being angled from the casing to the inner member in a direction downstream of the gas flow, the ends of each strut being circumferentially displaced, each strut of each pair being displaced in a different direction. Spherical seating means are provided for securing the ends of the struts to the casing and the inner member. The gas turbine engine exhaust system shown comprises an outer casing 1 and an inner fairing member 12, the member 12 being supported from the casing by a plurality of pairs of struts 26, the struts extending between an outer ring member 22 secured to the outer casing 1 and an inner ring member 24 to which is secured the inner fairing member 12. The outer ring member 22 comprises a casting 35 to which are secured ring members 36, 37, 38, the member 36 having a flange by which the assembly is secured to the outer casing 1. The casting 35 is formed with, openings in which the outer ends of the struts 26 are received. Each opening is formed with a part-spherical seat 50 and the outer end of each strut is formed with a corresponding part-spherical seat 52, the strut being secured with the seats 50, 52 in abutment by means of a ring member 56 which is locked in position by means of a locking washer 60, partspherical seating surfaces being formed on the end of the strut 26 and the ring member 56. The inner ring member 24 also comprises a casting 44 and ring members 45, 46, 47 the casting being formed with openings to receive the inner ends of the struts 26, a nut member 72 being secured at the inner end of the strut, the casting 44 and the inner end of the nut member being formed with part-spherical seating surfaces 66 which abut. The casting and the inner end of the strut are also formed with part-spherical seating surfaces 68, 70. The opening in the casting is formed with a recess 76 in which engages a lug 77 on the strut so as to prevent rotational movement of the strut in the opening. The struts are hollow for flow of cooling air therethrough from the space 104 between the outer casing 1 and the wall 34 to the space within the inner fairing 12. Some of the air passes through openings 106, 108, 114, 116, in the strut and into the spaces 110, 112, 118, 120 as shown. Cooling air is also supplied to spaces 124, 126, 134, 138 and discharges through outlets 130, 140 as indicated. The struts are of aerofoil section where they extend across the gas flow passage and of circular form at their ends. In a second embodiment, Fig. 6, the outer end of the strut 26a is screwed and a nut member 85 is engaged thereon; also the opening in the casting 81 is screwed internally and a nut member 87 is engaged thereon. The nut member 87 is formed with part-spherical seats 86, 92 which engage corresponding partspherical seats formed on the nut member 85 and the strut 26a respectively. The inner end of the strut is formed as a part-spherical member 98 which is engaged within a corresponding recess formed in ther inner ring member 82, the member being formed in two parts 82a, 82b which are secured together along the face 82c. The screwed members 85, 87 also the strut 26a are locked against rotation by means of a tabbed washer 99. The strut is again hollow for flow of cooling air. A frustoconical member 28 is secured to the inner ring 24, Fig. 4, the member 28 supporting a shaft bearing of the gas turbine engine.