US 3644057 A
A locking device utilizing a part-circular disc which, when rotated, serves to lock concentric cylindrical parts against axial or rotary movement or both, the disc then being retained in its rotated position to retain this locking arrangement.
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Description (OCR text may contain errors)
United States Patent Steinbarger 51 Feb. 22, 1972  LOCKING DEVICE 2,722,373 11/1955 Ledwith et a1. 415/218 2,766,693 10/1956 Zimmerman 415/218  Jay Steinbarge 3,069,135 12/1962 Welsh ....415/218  Assignee: General Motors Corporation, Detroit, 3,295,751 1/ 1967 Sceggel ..415/2l9 Mich. FOREIGN PATENTS OR APPLICATIONS  F11ed: Sept. 21, 1970 873,759 7/1961 Great Britain ..415/217  Appl. No.: 74,008
Primary Examiner-Henry F. Raduazo 52 us. 01... ..'......'.41s/21s, 415/199, 415/219 Arrorneylean L. Carpenter and Arthur Krein  Int. Cl ..F04d 29/40, F04d 29/00, FOld 9/00  Field otSearch ..415/ 193,194,199,216,217,  ABSTRACT 415/218" 219 A locking device utilizing a part-circular disc which, when rotated, serves to lock concentric cylindrical pans against  Reterences cued axial or rotary movement or both, the disc then being retained UNITED STATES PATENTS in its rotated position to retain this locking arrangement.
2,543,355 2/1951 Davis et a1. ..4l5/218 8 Claims, 6 Drawing Figures PAIENTEDFEB22 I912 3.644.057
7.2 1 W In 4 0, 0
A T TOPNEY LOCKING DEVICE This invention relates to a locking device and, in particular to a locking device for use in an axial flow turbine or similar device to lock concentric cylindrical parts against axial or rotary movement or both.
A known type of multistage axial flow gas turbine includes a plurality of external casing rings that are bolted together to form a turbine casing assembly in which are mounted a plurality of stator vane assemblies as by being peripherally flanged thereto for support. Such a gas turbine structure is disclosed in the US. Pat. No. 2,766,963, issued on Oct. 16, 1956, to Donald G. Zimmerman. In various such turbine assemblies, it has been difficult to mount the stator assemblies within the turbine casing to maintain a predetermined axial alignment of the stator assemblies within the engine housing or to fix the stator assemblies rotatively with respect to the turbine housing except by providing radially extending flanges on the stator assemblies which can be secured to suitable flanges formed on the turbine casing assembly, for example, as disclosed in the above identified U.S. Pat. No. 2,766,963.
Accordingly, the primary object of this invention is to provide a lock whereby to secure concentric cylindrical parts together against axial or rotary movement or both with respect to each other.
Another object of this invention is to provide a locking device of simple construction whereby to permit assembly and then locking together of concentric cylindrical parts.
These and other objects of the invention are obtained by means of a locking device in which a part-circular disc, having a semicircular aperture in the chord thereof is positioned in a semicircular spot-face opening in at least one flanged surface of a pair of radially extending flanges on outer tubular casings, the disc then being rotated to bring it into engagement with a groove, semicircular slot or semicircular spot-face opening in a concentric inner tubular mating piece. The flanges are bolted together with the bolt engaged in the semicircular aperture in the chord portion of the disc to lock it against rotation whereby the mating piece is thus secured by the part-circular disc against axial movement or rotary movement or both.
For a better understanding of the invention, as well as other objects and further features thereof, reference is had to the following detailed description of the invention to be read in connection with the accompanying drawings, wherein:
FIG. 1 is a sectional view of a portion of a turbine casing and stator assembly coupled together utilizing a locking device in accordance with the invention;
FIG. 2 is an enlarged view of a portion of FIG. 1 showing the locking device of the invention in locked position;
FIG. 3 is a sectional view taken along line 3-3 of FIG. 2 with a locking device being shown in locked position and another locking device being shown in an unlocked position;
FIG. 4 is an exploded perspective view of another embodiment of the locking arrangement of the invention;
FIG. 5 is a view similar to FIG. 2, but utilizing still another locking arrangement of the invention; and,
FIG. 6 is an exploded perspective view of the locking arrangement of FIG. 5.
Referring now to the drawings in detail, the turbine assembly comprises two major components, a turbine rotor assembly and a turbine casing assembly. The turbine casing assembly includes an outer casing structure that encircles the blade system of the turbine and an inner casing structure supported thereby and defining therewith the inlet and exhaust portions of the turbine and providing bearing support for the turbine rotor assembly. The outer casing structure includes a rigid multi-part external casing structure and a segmented, relatively flexible, stator-vane internal casing structure secured thereto. The turbine rotor assembly includes a bladed drum built up from alternating bladed discs and nonbladed spacer discs. The forenoted turbine construction may be conventional and therefore only so much of the structure as is necessary to enable one skilled in the art to understand the invention as illustrated.
A rear casing 10, an intermediate casing 12 and a forward casing 14 which comprise the primary structure components of the turbine casing assembly are bolted together at 16 and 18, the rear casing 10 supporting an exhaust casing structure, not shown. The forward casing 14 forms part of an inlet casing structure which includes an inner casing 20 and a forward bearing support plate 22 supported therefrom by radial construction, not shown. The turbine rotor assembly 24 includes blade discs 26 and spacer discs 28 suitably secured together for rotation in the turbine casing in the usual manner. The outer casing structure includes stator-vane assemblies supported from the casing 10, 12 and 14 by peripheral tongue and groove structures and held in axial alignment by a locking device in accordance with the invention, to be described hereinafter.
The stator-vane assemblies form the fixed blading for the turbine and an internal casing structure for the turbine casing assembly. The stator-vane assemblies include the outer shroud rings 30, 32, 34 and 36 and the inner shroud rings 38 secured thereto by the stator-vanes 40, the first stage inner shroud ring being additionally supported by the inner casing 20 and the remaining inner shroud rings serving as gas seals between the blading stages of the turbine rotor. Preferably, a heat shield 42 encircles the outer shroud 36.
The turbine unit is assembled with the outer shroud rings secured to the turbine casing in a manner to be described. As shown, the external casings 10 and 14 are formed with peripheral tongues 44, 46 and 48 that extend axially to support the stator-vane assemblies. The outer shroud 30 is formed at one end with a peripheral flange 50 received in the annular groove formed by tongue 44 of casing 10 and the inner surface of casing 12, and at its other end with a peripheral groove 52. Shroud 32 is also provided at opposite ends with a peripheral flange 54 received in groove 52 of shroud ring 30 and a peripheral groove 56. Outer shroud ring 34 is also provided at one end with a peripheral flange 58 received in the peripheral groove 56 of shroud ring 32 and at its other end with an axially extending shoulder portion 60 and peripheral groove 62, the shoulder portion 60 being received in the groove formed by tongue 46 of casing 14. Outer shroud ring 36 is provided with peripheral flanges 64 and 66 received in the groove 62 of shroud ring 34 and in the groove formed by tongue 48 of forward casing 14, respectively, the heat shield 42 also being engaged in these same grooves. Because a considerable tempera ture differential exists between the shroud ring assemblies and the external casing during engine operation, suitable clearances are provided between the tongue and groove fittings, just described, to permit for limited axial and radial expansion of the various assemblies with respect to each other.
At least one shroud ring, preferably an intermediate outer shroud ring such as ring 34, is fixed at one end axially with respect to the external casing and may, if desired, also be locked to prevent relative rotation with respect to the external casing by the use of circumferentially spaced apart locking devices 70, in accordance with the invention, engaged in suitable key slots formed in the outer shroud ring.
Referring now in part to FIGS. 1, 2 and 3, each locking device 70 is in the form of a part-circular disc or key having a circular edge portion 72 and a flat or chord portion 74 provided with semicircular notch 76 in the center thereof.
Each of the locking devices 70 is mounted in a semicircular spot-face 78 in the end wall of the flange 68 of intermediate casing 12 such that, when in an unlocked position, as shown by the right-hand locking device in FIG. 3, the chord portion 72 of the locking device is positioned out of engagement with the outer periphery of the outer shroud ring 34. To effect locking of the outer shroud ring 34 to the outer casing, the locking device 70 is rotated so that the circular edge portion 72 is rotated into a key slot 80 provided in the outer shroud ring 34. As shown in the embodiment of FIG. 3, the key slot 80 in this particular embodiment is in the form of a continuous annular slot of a suitable depth and width to receive the locking device 70. To facilitate rotation of the locking devices 70 from the unlocked to the locked position, a suitable screw driver slot 82 or other suitable aperture can be provided in each locking device70 to receive a tool such as a screw driver for convenience in rotating the disc.
After rotation of all of the locking devices to the locked position, the position of the left-hand lock disc of FIG. 3, the rear casing 14 can then be secured to the intermediate casing 12 by means of bolts 18 with a bolt 18 being engaged in the semicircular notch 76 of the locking device to lock the disc against rotation. With this arrangement, the outer shroud ring 34 is secured to the outer casing to prevent axial movement in both directions relative thereto while still being free to rotate relative to the external casing.
Referring now to the embodiment shown in FIG. 4, instead of the annular key slot 80, previously described, individual key slots 800 are provided in the outer shroud ring 34. In this embodiment, each of the key slots 80a are in the form of semicircular recesses of the desired diameter and width for the locking device 70 to be used therein. With this arrangement, the outer shroud ring 34 is secured against axial movement in both directions and against rotation with respect to the outer casing.
In the embodiment illustrated in FIGS. 5 and 6, the key slot is in the form of individual spot-face slots 80b for each of the locking devices 70 provided in the outer edge of the outer shroud ring 34, each spot-face being of the appropriate diameter and width to accommodate a locking device 70 when in the locked position, as seen in FIG. 5. This configuration of the key slot to receive the locking device will prevent axial movement of the outer shroud ring 34 in one direction only but will prevent rotation in both directions of the outer shroud ring with respect to the outer casing.
Although the spot-faces 78 have been shown as being formed in only one of the two mating flanges of the casings l2 and 14, it is to be realized that if so desired, both flanges can be spot-faced to the desired depth to accommodate the locking devices between the two flanges.
What is claimed is:
1. An elastic fluid turbine including a plurality of flanged casing rings secured together by bolts to provide an annular casing, a stator-vane shroud ring assembly disposed in said casing, a peripherally extending tongue and groove structure on said casing and said shroud ring assembly for mounting said shroud ring assembly in said casing, a plurality of circumferentially spaced apart semicircular spot-face openings in the end surface of one of said flanged casing rings, key slot means in the peripheral surface of said shroud ring assembly, and
particularly key discs positioned in said spot-face openings in engagement in said key slot means, said key discs including retaining means thereon engaged by said bolts to secure said particular key discs in engagement in said key slot means.
2. An elastic fluid turbine according to claim 1 wherein each of said part-circular key discs is provided with a circular edge portion and a chord portion with a semicircular notch in the center thereof and each of said key discs is adapted to be rotatively positioned in one of said spot-face openings for movement from a position in which said circular edge portion is out of engagement with said shroud ring assembly to a position in which said circular edge portion is in engagement with said key slot means in said shroud ring assembly.
3. An elastic fluid turbine according to claim 2 wherein said key slot means is an annular groove in said shroud ring assembly.
4. An elastic fluid turbine according to claim 2 wherein said key slot means is a plurality of circumferentially spaced apart semicircular recesses in said shroud ring assembly of a diameter and width to receive said circular edge portions of said key discs.
5. An elastic fluid turbine according to claim 2 wherein said retaining means is provided by said semicircular notch in said chord portion being engaged by one of said bolts in said flanged casing rings.
A locking device for securing concentric cylindrical outer and inner parts together, the outer part including a pair of flanged hollow members secured together by bolts, a plurality of circumferentially spaced apart semicircular spot-face openings in the end surface of one of said flanged hollow members, key slot means in the peripheral surface of said inner part, a plurality of part-circular key discs each provided with a circular edge portion and a chord portion with a semicircular notch inthe center of said chord portion positioned in said spot-face openings for movement from a position in which said circular edge portion is out of engagement with said inner part to a position in which said circular edge portion is in engagement with said key slot means in said inner part, one of said bolts engaging said semicircular notch in said chord portion when said circular edge portion is in engagement with said key slot means to retain said part-circular key disc against rotative movement in said spot-face opening.
7. A locking device according to claim 6 wherein said key slot means is an annular groove in said inner part.
8. A locking device according to claim 6 wherein said key slot means is a plurality of circumferentially spaced apart, semicircular recesses in said inner part of a diameter and width to receive said circular edge portions of said key discs.