Abstract: A fan blade retention device includes a retaining flange (18) located aft of the blade fixing element (7). The flange (18) abuts an outwardly facing circumferential groove (13) located between the flange (18) and the female half of the blade fixing element (10). The groove (13) is large enough to allow the blade fixing element (7) machining tool to be removed. The fan blade (28) includes an extension (21) of the blade root (11) on the aft side of the blade (28). When the blade root (11) is fully received within the female half of the blade fixing element (10), the blade extension (21) spans the width (20) of the groove and contacts the flange (18), thereby preventing the fan blade (28) from traveling aft.

Abstract: Steam turbine blades and buckles are attached to a rotor with pins which fit through dove-tailed connections. In one extremity of the blade and a mating position on the rotor. The pins are composed of a first material which is in a state of compression due to shot peening, a second metallic material being on the surface of the pins. The second metallic material is not as hard as the first material and provides a relative lubricating surface to facilitate removal from a mating aperture in the dove-tail formations.

Abstract: A device for locking the blade roots (3) in rotor disk alveoli (2) consists of a single split ring (9) with a Y shaped cross-section of which a radial upstream arm (9a) is inserted in the groove (7) of the downstream blade lips (6) the radial downstream arm (9b) of the ring (9) being pressed against the downstream part of the blade lips (6).

Abstract: A bladed disc of a turbomachine rotor comprising an array of blades evenly disposed around the rim of the disc and separate platforms secured to the disc between the blades, each platform comprising a plate and a mounting foot at each axial end of the plate by which the platform is secured to the rim of the disc, at least one of the feet being secured by a C-shaped clamp which rigidly connects the foot to a tooth-like element of the disc adjacent the rim and which is locked axially in position by a flange of an adjacent element of the rotor.

Abstract: A rotor for an axial flow turbomachine includes a disc, a rim on the disc having blade retention slots, and blades having roots in the slots and airfoils extending radially out from the rim. The airfoils project through correspondingly shaped slots in a cylindrical platform concentric with the rim of the rotor. A first annular flange at one end of the platform has a lip at its inside diameter which hooks under the inside diameter of a first annular flange on the rim for radial retention of the platform. A second annular flange at the other edge of the platform has a lip at its inside diameter which hooks under a lip at the outside diameter of an annular cover. The cover has another lip at its inside diameter which hooks under a second annular flange on the rim for radial retention of the cover and the platform.

Abstract: A balance weight for the rotor of a gas turbine engine is adapted to mount within the cavity formed between the innermost surface of the dovetail slots formed in the circumference of the rotor disk and the bottom of the dovetail root of the rotor blades inserted within the dovetail slots. The balance weight has a head portion formed with a bottom surface which mates with the innermost surface of the dovetail slots, and a lip connected to the head portion which engages the aft surface of the rotor disk. The balance weight is supported in an aft direction within the dovetail slots by an aft blade retainer having a shoulder or projection which contacts the balance weight.

Abstract: Each blade of a turbomachine rotor is secured to the drum of the rotor by upstream and downstream legs on the radially inner side of the blade platform cooperating with upstream and downstream annular beads on the periphery of the durm, and a locking plate holding the legs in position. The end of the upstream leg is received in an annular groove in the upstream bead, and the downstream leg has an aperture which receives a tongue projecting from a collar on the downstream bead. the downstream leg ends in a cylindrical bearing surface acting on a cylindrical bearing surface of the drum, and includes two hooks on its donwstream face. The locking plate is located in an annular groove of the drum at the downstream edge of the cylindrical bearing surface and has first tongues engaging with the hooks on the downstream leg and second locating tongues at each end.

Abstract: A rotor blade (1) is disclosed which recenters itself in relation to the rotatable hub in which it is installed. Imposition of an external force (A) upon the rotor blade (1) creates a moment (M) which acts about the rotor blade's root (2). Recentering is accomplished by centrifugal forces acting through an offset distance (C) resulting from rotation of the blade root (2) about a shaped retaining pin (6), achieving an enhanced opposing restorative moment (M') on the rotor blade (1). The rotor blade (1) contains an arcuate bearing suface (8) within a chordwisely disposed slot (7) in the rotor blade's root (2). This arcuate surface (8) bears against a mating arcuate surface (9) with a smaller radius of curvature lengthwise disposed on the shaped retaining pin (6).

Abstract: In an arrangement for mounting a shrouded pivotable propfan blade at a rotor, the propfan blade is held in a dovetail mounting of a blade carrier and, by using a first securing device is fixed with respect to axial movements of the propfan blade. The blade carrier is secured with respect to radial movements by means of a second securing device, which is accessible from the outside. This permits a simple and fast mounting and demounting of the propfan blades.

Abstract: In a turbomachine, such as a turboshaft aero-engine, having a compressor casing composed of upstream and downstream casing rings, and a variably settable stage of stator blades which is mounted in one of said casing rings near the junction therebetween so that, in normal operation, the blades have their leading (or trailing) edges projecting into the other casing ring, the setting of the blades being adjusted by a control ring surrounding the casing, there is provided a locking system for temporarily locking the blades in an angular setting in which the leading (or trailing) edges are retracted clear of said other casing when the casing is to be dismantled or assembled.

Abstract: Rotor blades have feet engaged in axial grooves in a rotor disc and foot plates on the blades form with the surface of the rotor disc, axially and circumferentially extending intermediate spaces. Between sections of the blades and the rotor disc, overlaps of structural parts are developed at the intermediate spaces, by which the blades are fixed axially in the grooves in one direction. The overlaps of the structural parts can be formed between profiled or ground contours surfaces of the blade feet and profiled or broached contours surfaces of the rotor disc.

Abstract: An apparatus and method is provided for locking side entry blades, in a rotor, such as used in compressors, turbines and fans. The apparatus utilizes arcuate locking devices retained in a circumferential groove in the periphery of the rotor. Each locking device features a key which engages a keyway in the side of the blade root shank. Use of the locking devices does not require that the blades having abutting platforms.

Abstract: Method and apparatus for assembling integral platform blade groups to a rotor of a steam turbine in which the platform roots are skewed with respect to the axis of the turbine. The platform roots are formed to define a set of spaced grooves and steeples are formed on the rotor to mate with the platform roots. Grooves on the platform and in the rotor are alignable to accept a connecting member when the steeples are aligned in abutting relationship with platform roots. The connecting member joins the blade group to the rotor. In one form, the bearing surfaces of the steeples, roots and connecting member are formed to lie on one or more circles circumscribing the rotor axis.

Abstract: A boltless blade retainer for preventing forward axial movement of the rotor blades in a turbo machine relative to the rotor disk comprises an annular extension or hook formed on each dovetail post on the web of the rotor disk, an impeller or blade retainer formed with a flange which is carried against the web and dovetail posts and a retaining ring interposed between the hooks of the dovetail posts and the flange of the impeller. The retaining ring secures the impeller in a fixed axial position relative to the dovetail posts and rotor disk, and is positioned to engage the rotor blades carried in the axial slots between adjacent dovetail posts to prevent their movement in a forward axial direction.

Abstract: Damping of a turbine rotor is attained by a weighted member trapped between pockets formed in the neck of adjacent blades at one end and a space between the disk and TOBI rotor seal and forward extending blade lug at the other end. The feather seal which is a curved plate fits over the top of the weighted member and is trapped between nubs formed on the front and rear underside of the blade platform. The front face of the rim of the disk at the disk cavity is open ended and blocked off at the rear face. This assembly allows for individual blade removal and viewing from the rear face by removing a single rim cavity cover without disturbing the remaining components of the assembly. The inverted ring supports take up the axial loads alleviating the loads heretofore taken up by the TOBI rotor seal, allowing for a lighter weight installation.

Abstract: A rotor assembly for use in a rotodynamic machine comprises a rotor disc (10) with a plurality of blades (14) attached to its outer rim (12) and a seal plate (22) for substantially preventing the escape of blade cooling air. The rotor disc (10) is provided with a plurality of hooked restraining members (30) each including a radially inward directed abutment face (32) which in use restrain the seal plate from moving axially and from moving radially outward under centrifugal force by abutment with the seal plate. In this way the blades (14) are not subjected to additional loading by the seal plate (22).

Abstract: A rotor assembly (34) includes a disk (36) having an axially extending, unbroken annular spigot (38). The spigot (38) supports a plurality of radially extending lugs (42) which are juxtaposed with a corresponding plurality of dogs (14) integral with an annular sideplate (12). A smooth key (54) fits within the opening (44) formed between adjacent engaged dogs and lugs (14, 42) and is retained axially by a sheet metal retainer (46) received through a slot (52) disposed in the key (54).

Abstract: A blade support and blade assembly has a cylindrical blade support with a slot in the outer periphery, the root of a blade disposed in the slot. The blade root has a groove in the bottom surface into which a locking pin, biased by a spring, is biased into the groove to lock the blade to the blade support. A bore is formed completely through the blade base extending from the outer surface thereof to the location of the locking pin, and a pin displacement, which may be a rod or a supply of pressurized fluid is operative to displace the pin from the groove in the blade base to permit removal of the blade root from the slot in the blade support. Hardened inserts may also be provided, either in the blade root or the blade support slot to strengthen the area of contact of the locking pin with the blade support and/or the blade root.

Abstract: Two-part turbine-blade retainer structures are disclosed for axial retention of each of a plurality of turbine blades to a rotor wheel, wherein radial retention is via fir-tree engagement of individual blade roots to the wheel. In a preferred embodiment, a male or bolt element of the retainer has a shank which is characterized by a smoothly cylindrical portion adjacent at one end to one of the heads; this cylindrical portion terminates at a shoulder, beyond which the shank is reduced and externally threaded. A sleeve or nut element of the retainer has an elongate threaded bore and is characterized by an outer cylindrical surface which extends to the second head. The two elements are proportioned to be inserted through opposite ends of a passageway and to be screwed together into firm engagement at the shoulder (i.e., at a location intermediate the two heads), with the sleeve covering the threads of the male element and the heads preventing the turbine blade from axial motion with respect to the wheel.

Abstract: A process provides a method for attaching a turbine blade to a blade support such as a rotor or rotor disc of a turbine. The root portion of the blade is formed to a shape approximately that of a groove in the surface of the rotor or rotor disc and the root portion of the blade is inserted within the groove. A composition comprising a particulate compound selected from the group consisting of a ceramic, graphite metal, metal alloy and mixtures thereof is positioned between the root portion of the blade and steeples, located one on either side of the groove.

Abstract: A steam turbine of the type employing a plurality of axial entry blades has a first annular plate juxtaposed one side of the disc that overlays the grooves in the disc and faces of the platforms of the blades. If desired, a second similar annular plate may be provided on the other side of the disc. The annular plates reduce windage and leakage.

Abstract: Two-part turbine-blade retainer structures are disclosed for axial retention of each of a plurality of turbine blades to a rotor wheel, wherein radial retention is via fir-tree engagement of individual blade roots to the wheel. In a preferred embodiment, a male or bolt element of the retainer has a shank which is characterized by a smoothly cylindrical portion adjacent at one end to one of the heads; this cylindrical portion terminates at a shoulder, beyond which the shank is reduced and externally threaded. A sleeve or nut element of the retainer has an elongate threaded bore and is characterized by an outer cylindrical surface which extends to the second head. The two elements are proportioned to be inserted through opposite ends of a passageway and to be screwed together into firm engagement at the shoulder (i.e., at a location intermediate the two heads), with the sleeve covering the threads of the male element and the heads preventing the turbine blade from axial motion with respect to the wheel.

Abstract: A retainer ring clamps, for example, a turbine cooling plate to a rotatable turbine disc. The retainer ring has a wedge-shaped channel that engages annular flanges on the cooling plate and the disc. The wedge-shaped channel converts radial forces on the ring to axial clamping forces which secure the cooling plate to the disc. Special tooling is not required to assemble the retainer ring to the cooling plate and turbine disc, and preloading of the cooling plate against the disc is not necessary. An angled or slanted gap in the ring eases assembly and disassembly of the retainer ring onto the annular flanges of the cooling plate and turbine disc and ensures that axial and radial movement of the retainer ring is required for disassembly of the ring from the flanges.

Abstract: A steam turbine of the type employing axial entry blades is provided with a plurality of generally tangentially oriented slots in the rotor steeples. Resilient, deformable pins are driven into the slots under the blade platforms so as to urge the blade roots radially outward.

Abstract: A redundant locking system for the closing blades of a circular array of curved Christmas tree-shaped roots of side entry freestanding steam turbine blades which have registering holes in the platform of the closing blades and the blades adjacent to the closing blades which receive pins, the pins fit tightly into the through holes and loosely into the hole in the adjacent blade to lock the closing blades in place and allow each blade to vibrate independently.

Abstract: A locking and sealing system is disclosed for attaching a rotor blade to a rotor blade disk in a turbojet engine. The system has a first split ring member which locks the rotor blade foot portion onto the rotor blade disk. A second split ring member is inserted between the first split ring member in a downstream flange of the rotor blade foot portions to provide a positive seal to prevent air leakage between the foot portions and the notches formed in the rotor disk.

Abstract: A turbomachine rotor disc assembly includes a rotor disc having a plurality of blade-root grooves in its periphery, each two adjacent grooves defining a lobe lug between them. Rotor blades each include an aerofoil portion, a root portion, a platform defining the radially inner boundary of the aerofoil portion, and a stilt portion interconnecting the radially inner face of the platform and the root portion, a free space being defined between each adjacent pair of blades. The angular clearance of each blade in its groove is limited by wedges operative between adjacent blades on the stilts thereof and connecting members carrying the wedges secured to the rotor disc and capable of transmitting shock loads and distributing resultant forces over an adjacent sector of the rotor. The wedges are so dimensioned in relation to the dimensions of the stilts of adjacent blades that the angular clearance is limited to the permissible angular clearance of each blade during auto-rotation of the rotor.

Abstract: A turbine rotor disk assembly for an axial flow gas turbine engine includes a rotor disk (18) and a faceplate (22) axially engaged therewith by rotationally engaged securing means such as a pair of corresponding hooked members (42, 44). Disengagement of the faceplate (22) and the rotor disk (18) is prevented by the cooperation of an axially projecting tab (58), integral with the turbine blade, (20) and a corresponding faceplate recess (60).

Abstract: A multifunctional labyrinth seal support disk for a turbojet engine rotor is disclosed which also serves to axially lock the rotor blades onto the rotor wheel. A radial support disk has a generally conical, labyrinth seal means extending from the disk in an upstream direction and a conical collar extending from the disk in a downstream direction. The collar has a generally annular bearing surface which bears against an upstream side of the rotor blade roots. Several blade-retaining teeth extend from the collar in a downstream direction and are dimensioned so as to fit within axial grooves between the blade root and the rotor blade wheel. Radially extending spurs bear against the downstream portion of the rotor blade root to axially lock the rotor blade onto the disk. An attaching ring is interposed between the blade retaining teeth and the rotor blade wheel so as to axially lock the multifunctional disk with respect to the rotor blade wheel.

Abstract: The cover plates defining windage covers adjacent the broached rim of the turbine disk has the dual function of insulating the disk rim by defining a gap between the rim and turbine blades for receiving cooler air and insulating the disk from the gas path resulting in a cooler disk.

Abstract: The invention comprises a retrofit turbine blade cooling apparatus for replacing non-cooled turbine blades in presently existing combustion turbines. The cooling apparatus comprises a turbine blade structured for fluid cooling and a sealing apparatus structured to cooperate with a root portion of the turbine blade and a subadjacent portion of a turbine disc to force cooling fluid into the turbine blade. Use of the cooling apparatus requires no modification or disassembly of the rotor assembly.

Abstract: A seal means 66 for a blade attachment slot of a rotor assembly 12 is disclosed. Various construction details which adapt the rotor assembly to block the leakage of cooling air from the blade attachment slot 40 as the cooling air is flowed to a rotor blade 22 are developed. In one embodiment, the seal means has a seal plate 68 and baffles 70,72 integral with the seal plate which define a cooling air chamber for receiving cooling air from a passage way 38 in a rotor disk 20. The seal plate extends axially and laterally to block the leakage of cooling air in the radial direction. Baffles extend radially from the plate for blocking the leakage of cooling air in the axial direction.

Abstract: A device for axially locking a turbine blade onto a rotor disk includes a foot portion of the blade which is slidably retained in a slot provided on the periphery of the rotor disk. An axial projection extends from the foot portion so as to engage a locking ring attached to the rotor disk when the blade is moved in a radially outward direction. A block inserted between the foot portion of the blade and the rotor disk serves to impart such movement to the rotor blade. Brackets on a downstream compressor drum and an upstream cover portion serve to axially lock the block in position.

Abstract: An impeller for an axial fan, this impeller comprising a hub transversally split into two parts each defining recesses into root portions of a plurality of impeller blades are inserted and locked by means of key-pieces when the two parts are joined together. Each key-piece has two spaced projections on one side for engaging two corresponding recesses diametrically located in the end surface of the root of each impeller blade close to the periphery of this end surface, and two equally spaced projections on its other side for engaging two corresponding recesses provided in the bottom surface of the recess in the hub. These pairs of projections on both sides of the key-piece which is preferably ring-shaped, are advantageously shifted from a certain angle along the circumference of the ring. The amount of angular displacement of the projections can be determined by mere adjustment of the mold in which the key-pieces are produced.

Abstract: A rotor stage assembly 20 of the type adapted for use in an axial flow gas turbine engine is disclosed. The assembly includes a rotor disk 36, at least two rotor blades 42 and a scalloped lock pin 52. The scalloped lock pin has lugs 54. The disk is adapted by a groove 40 and each blade is adapted by a groove 48 to receive the scalloped lock pin. During assembly the scalloped lock pin is alignable with blade attachment slots 44 in the disk to enable insertion of the blades and is slidable in the grooves 40, 48 to bring each lug 54 on the scalloped pin into engagement with a corresponding groove in a rotor blade.

Abstract: A device for securing an annular blade retaining plate to a rotor disk includes an annular groove around the disk for receiving an off-set annular flange on the inner end of said blade retaining plate. A split retainer ring extends from a second groove intersecting said first groove to fix the blade retainer ring to the disk. A locking ring is positioned between said split retainer ring and said blade retaining plate to maintain said split retainer ring in its groove.

Abstract: The rim of the rotor disk has teeth formed by axial grooves. The grooves accept the bases of the blades, which are radially locked by wedges placed between the root and the bottom of the groove. The blade base is extended by a shank bearing the platform and the blade. The locking device comprises locks provided on at least part of the sides of the spindle, and housing provided in the teeth and shaped in such a way that they interact with the locks when the wedge is placed between the blade base and the bottom of the groove. According to one embodiment, the locks are formed by the portions which extend from a locking part lodged in a notch of the blade base and of the shank.

Abstract: An end seal for cooling air manifolds below the bases of a stage of air cooled turbine blades on a turbine wheel, the end seal including a seal ring having an annular planar portion abutting an end face of the turbine wheel inboard of the air manifolds and a right cylindrical flange perpendicular to the planar portion and underlying a corresponding cylindrical shoulder on the wheel and on the blade bases outboard of the air manifolds, and a plurality of end plates on the wheel having lugs underlying the cylindrical flange. The planar portion is axially clamped to the wheel to define a 360.degree. inboard seal while centrifugal forces developed by the end plates during rotation of the wheel cause the lugs to radially clamp the cylindrical flange against the cylindrical shoulder on the wheel and blade bases to define a 360.degree. outboard seal.

Abstract: An axial locking device for blades of a fan, each blade including a root of dovetail or other re-entrant form engageable by axial sliding in corresponding grooves of the rim of the fan disc. A locking member is provided in the form of a key of parallelepiped form abutting the root of the blade. The key is locked against radially outward motion by a peripheral extension from one longer edge which engages a tab member having a portion which is secured to a front face of the fan rim. The key engages radial slots in the rim and in an alternative embodiment, the key is secured radially by a bolt which passes through a forward part of the rim, an end portion of the key and into a tapped bore of the main body of the rim.

Abstract: Gas turbine engines are used as powerplants for aircraft. When the aircraft are parked on the ground, the wind can blow through the engines and set fans and rotors into motion, i.e., windmill them. Given that the blades of the fans and rotors are loosely fastened to their rotors, the low speed rotation caused by windmilling causes the blades to clatter or clank, thus causing wear. The present invention provides means for clamping blades into position during this low speed rotation for reducing clanking.

Abstract: The Assembly has a submerged root, turbine-wheel-blading configuration, and utilizes circumferentially oriented, buried, friction damping wires, and continuous, overlapping, tip shrouds to minimize vibratory response. The wires, in the presence of blade vibration, simultaneously rub on both the blades and surfaces of a recess in the wheel in which the blade roots are fixed. The continuous tip shrouding provides additional damping through shroud-to-shroud interface rubbing. The assembly has a stack of identical blades, obviating any need for relatively weak locking blades or pieces. The method defines the steps of forming a peripheral recess in a wheel, in which to secure root ends of blades, and setting the damping wires (or wire) therein prior to installing the blade root ends, and uniformly spacing-apart the blades after securing the same to the wheel.

Abstract: A dovetail of a rotor blade is preferentially remove to thereby modify the support given to the root of a rotor blade. The modified support changes the vibrational characteristics of the rotor blade for reducing the tendency toward crack initiation. In one embodiment of the invention, one or more damping masses are fitted into the dovetail slot within the removed portion of the dovetail. The damping masses are loaded outward against the base of the rotor blade by centrifugal force and frictionally damp some of the vibrational energy of the rotor blade.

Abstract: A blade retainer for holding a turbine blade on a turbine rotor disc and sealing a cooling cavity formed between the disc and blade has a two-piece construction. The first piece performs the blade loading function, while the second piece performs the cavity sealing function. The two pieces are attached to the disc by a common set of fasteners, such as bolts.

Abstract: A device for damping vibrations of mobile turbine blades, in which the roots of the blades are engaged in recesses distributed over the periphery of a rotor disk on which is anchored, under the rim of the disk, a leading edge flange consisting of sections and a trailing edge flange consisting of a single annular part against which the blade roots and the teeth of the disk rest. Between the root of a blade and the bottom of the recess of the disk is placed, behind the forward flange, a shim in the shape of a wedge which, under the action of centrifugal force, exerts on the blade a force that causes the blade to slide axially so that it contacts trailing edge retaining flange.

Abstract: Axial and radial fan blade retention device, the blade comprising a root of dovetail or other re-entrant form capable of being engaged by axial sliding in corresponding bores of the rim of the disc.It comprises a member of elastomer material in the form of a trough extending axially and interposed between a wedge and the flanks and the base of a groove, the trough having an opening in which is engaged an abutment of the wedge constituting a central seating of the wedge on the base of the groove.

Abstract: Dovetail spacers containing slots enable final balancing of a turbine or compressor rotor or wheel without employing grooves or drilling holes in the wheel itself. The spacers are installed in the normal fashion and, when final balancing is performed, appropriate weights are inserted into the slots in selected ones of the spacers. Fine tuning can be performed by drilling or grinding the weights. In one embodiment, the spacer is provided with a radial hole which joins an axial hole. After the turbine or compressor rotor is assembled, additional counterweight material can be added through the radial hole and then be held in place by suitable means such as a setscrew. In this embodiment, weights of suitable material can also be removed as necessary.

Abstract: A blade holding system including a block 13 formed of an elongated part 15 having a lengthwise slot 18 extending over virtually its entire length. The longitudinal sides 181, 182 have openings 23 that receive an axle 17 holding a flexible strip 16 partially lodged in the slot. The flexible strip has two shanks 25, 26. The end 29 of one of the shanks 26 rests on one end 21 of the elongated part 15, the end 28 of the other shank 25 juts out from the lower plane of the elongated part 15 and, when the block 13 is in place between the blade foot 6 and the dovetail groove 2, is able to rest against the bottom 14 of the groove 2.

Abstract: The sideplates of a turbine rotor assembly that seal between turbine stages are retained by a retention assembly that hooks onto the front sideplate and is riveted onto the rear plate negating the necessity of rivet holes in the front sideplate. A plurality of segmented sideplates circumscribe the full hoop of the rotor and each sideplate carries a retention assembly rather than providing a retention assembly for each blade which is greater in number.

Abstract: The device has two ring segments (13) held in a circumferential score (11) provided in one edge of the upper surface (8) of the rotor disk. These ring segments consist of a portion of a cylindrical band (17) on whose edges are provided two collars (18, 19) of unequal thickness. The thicker collar (18) is placed between the upper wall of the transverse score (7) made in the projection (6) and the upper wall (8) of the rotor (1). The cylindrical band (17) works in conjunction with the bottom of the circumferential score (11). The thinnest collar (19) leans against the upper wall of the groove. The two segments placed end to end leave between them a space corresponding to the width of one axial notch. By displacing the ring segments in the score, the space is brought opposite the blade to be changed. The locking ring has two pins (21) which engage between the ends of the ring segments and block them in position. Other types of applications are described.

Abstract: The device is composed of a conical section located on the edge of the disk rim. The greatest radius of the conical section is at least equal to the radius of the circumference passing through the bottom of the axial grooves into which the blade roots are inserted. A groove is formed in the end of the lower part of the root, this groove having a right angle triangular section. A locking part has one face pressed against the bearing and two other faces against the sides of the groove in the root. A blade extending longitudinally in the locking part works together with a groove in the slot of the blade root to keep the locking part in place.