CA1128869A - Positive locking split-nut blade retaining assembly - Google Patents
Positive locking split-nut blade retaining assemblyInfo
- Publication number
- CA1128869A CA1128869A CA333,491A CA333491A CA1128869A CA 1128869 A CA1128869 A CA 1128869A CA 333491 A CA333491 A CA 333491A CA 1128869 A CA1128869 A CA 1128869A
- Authority
- CA
- Canada
- Prior art keywords
- split
- nut
- deformable portion
- diameter
- set screw
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000001737 promoting effect Effects 0.000 claims 2
- 230000001419 dependent effect Effects 0.000 claims 1
- 238000003780 insertion Methods 0.000 description 5
- 230000037431 insertion Effects 0.000 description 5
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 238000006748 scratching Methods 0.000 description 1
- 230000002393 scratching effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
- F01D5/32—Locking, e.g. by final locking blades or keys
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
- F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
- F01D5/3023—Fixing blades to rotors; Blade roots ; Blade spacers of radial insertion type, e.g. in individual recesses
- F01D5/303—Fixing blades to rotors; Blade roots ; Blade spacers of radial insertion type, e.g. in individual recesses in a circumferential slot
- F01D5/3038—Fixing blades to rotors; Blade roots ; Blade spacers of radial insertion type, e.g. in individual recesses in a circumferential slot the slot having inwardly directed abutment faces on both sides
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B35/00—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws
- F16B35/005—Set screws; Locking means therefor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B37/00—Nuts or like thread-engaging members
- F16B37/04—Devices for fastening nuts to surfaces, e.g. sheets, plates
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B37/00—Nuts or like thread-engaging members
- F16B37/08—Quickly-detachable or mountable nuts, e.g. consisting of two or more parts; Nuts movable along the bolt after tilting the nut
Abstract
ABSTRACT OF THE DISCLOSURE
A split-nut retaining assembly is provided wherein a set screw includes a deformable portion having a first diameter in a first mode whereby the set screw may be inserted into position. Upon complete tightening of the set screw the deformable portion has assumed a second diameter whereby the retaining assembly is locked into position.
A split-nut retaining assembly is provided wherein a set screw includes a deformable portion having a first diameter in a first mode whereby the set screw may be inserted into position. Upon complete tightening of the set screw the deformable portion has assumed a second diameter whereby the retaining assembly is locked into position.
Description
In general, this invention relates to a split-nut blade retaining or locking assembly and more particularly to a positive locking split~nut blade retaining assembly for securing a plurality of circumferentially spaced blades disposed about the periphery of a rotor disc.
In the axial flow compressor art, it is well known to dispose a plurality of circumferentially spaced blades about the outer periphery of a rotor disc element. Each blade so disposed includes a vane section extending outward from the periphery of the rotor disc and a root portion extending ~n a substantially inward radial direction from the periphery of the rotor disc. It is also well known in the art to radially and axially retain the blades in the rotor by means of a doveta;l groove around the outer periphery thereof.
The blade root po~tlons are thickened at the inner radial end to provide outwardly extending shoulders which abut the inwardly directed faces of the dovetail groove. Assembly of the blade roots into the dovetail groove is ordinarily accomplished by inserting a blade root through a narrow, 2Q entrance slot, cut into the dovetail groove at one or more discrete points along the circumference of the spool and then sliding the blades in the do~etail groove into their respective positions. Means must be provided ~or locking the blades in circumferential position along the periphery of the rotor disc. The locking means must be capable of withstanding the circumerential component of the aerodynamic load ; developed during compressor operation. At the same time, the locking device must be capable of permitting assembly and disassembly of the blade members to the spool with relative 3Q ease.
One pr;or art locking assembly, as shown in United States Patent No. 3,721,506 - dated March 20, 1973 -~nderson, was significant advancement in the art and for all , ~
~3~
intents and purposes has proved to be a satisfactory mechanism. However~ it has been found that under use in the environment of a gas turbine engine, various components of that locking assembly were subject to loosening due to the vibrations inherent in the engine itself. The present invention is directed to~ard an improvement to the invention described and claimed in the aforementioned patent.
It is therefore an object of this invention to provide a blade retaining assembly which permits ready assembly and disassembly of the blades of a rotor disc element.
It is another object of the present invention to proyide a blade retaining assembly which is positively locked in position whereby vibrations due to engine operations are ineffectiye to cause undesirable removal of the assembly.
Briefly stated these and other objects which will become apparent from the following detailed description and accompanying drawings are accomplished by the present inyention which in one form provides a split-nut locking assembly for attachment to a groove wherein the split-nut includes a collar having two arcuate segments each having threaded portions spaced from each other by a minor diametrical distance between peaks of opposed threads on each of said segment. The split-nut further includes an undercut adjacent said threaded portions, the undercut having a diameter greater than the a~orementioned minor diameter. A
wrenching set screw having a deformable portion is disposed in a first mode wherein the deformable portion has a first diameter less than the minor diameter. The deformable portion is deformable to a second diameter greater than the minor diameter.
~hile the specification concludes with claims distinctly claiming and particularly pointing out the ~P2,~æ~
invention described herein, it is believed that the invention will be more readily understood by reference to the discussion below and the accompanying drawings in which:
FIG. 1 is a perspective view showing the locking assembly of this invention as assembled within a portion of a rotor disc.
FIG. 2 is an exploded perspective view showing the locking assem~ly of FIG. 1 in combination with a portion of a rotor disc.
FIG. 3 is a cross-sectional view showing a split-nut disposed within the rotor groove.
FIG. 4 is a cross-sectional view of FIG. 1 taken along the line 5-5 with the wrenching set screw only partially inserted.
FIG. 5 is a cross~sectional view of FIG. 4 with the wrenching set screw fully inserted.
FIG, 1 shows a portion of a rotor assembly 10 of the type commonly includes in an axial flow compressor which may form an integral part o~ a gas turbine engine. The rotor assembly 10 is shown as including a rotor disc 11 having axially spaced apart, opposed faces 12 and 14, both of which are substantially normal to the axis of rotor rotation.
The rotor disc 11 includes a plurality of circumfexentially spaced apart blade 22 and 24 disposed about its periphery. The blades 24 are end locking blades specially adapted to acc~mmodate the split nut blade locking assembly of this inYention shown generally at 37 and which will hereinafter be described in full detail. Each of the blades 22, 24 includes an airfoil vane section 26 between which gas 3~ flow may be directed for compression in a manner well known to the art. The blades 22, 24 also include platforms 28, 30 respectively from which dovetail root portions 32 extends substantially inward in the radial direction. The platforms 28 and 30 generally overhang the root portions 32.
The blades 22, 24 are radially and axially retained by means of a circumferential dovetail groove 16 extending around the outer periphery of the rotor disc 11. The dovetail groove 16 includes a pair of side walls 18 which are undercut to provide inwardly directed abutment faces 20. Each dovetail root portion 32 is thickened at the inner radial end to provide outwardly extending shoulders 34 which abut the inwardly directed faces 20 of the dovetail groove, thereby radially retaining the blades under centrifugal loading.
Referring now to FIG. 2, the circumferential dovetail groove 16 includes a circular entrance slot 36 therein, to accommodate insertion of the individual blade root portions 32 into the dovetail groove 16. Each blade root portion 32 is individually inserted through the circular entrance slot 36 for engagement with the opposing surfaces of the dovetail groove 16. After insertion each blade 22 is circumferentially slid around the dovetail groove 16 into platform abutting
In the axial flow compressor art, it is well known to dispose a plurality of circumferentially spaced blades about the outer periphery of a rotor disc element. Each blade so disposed includes a vane section extending outward from the periphery of the rotor disc and a root portion extending ~n a substantially inward radial direction from the periphery of the rotor disc. It is also well known in the art to radially and axially retain the blades in the rotor by means of a doveta;l groove around the outer periphery thereof.
The blade root po~tlons are thickened at the inner radial end to provide outwardly extending shoulders which abut the inwardly directed faces of the dovetail groove. Assembly of the blade roots into the dovetail groove is ordinarily accomplished by inserting a blade root through a narrow, 2Q entrance slot, cut into the dovetail groove at one or more discrete points along the circumference of the spool and then sliding the blades in the do~etail groove into their respective positions. Means must be provided ~or locking the blades in circumferential position along the periphery of the rotor disc. The locking means must be capable of withstanding the circumerential component of the aerodynamic load ; developed during compressor operation. At the same time, the locking device must be capable of permitting assembly and disassembly of the blade members to the spool with relative 3Q ease.
One pr;or art locking assembly, as shown in United States Patent No. 3,721,506 - dated March 20, 1973 -~nderson, was significant advancement in the art and for all , ~
~3~
intents and purposes has proved to be a satisfactory mechanism. However~ it has been found that under use in the environment of a gas turbine engine, various components of that locking assembly were subject to loosening due to the vibrations inherent in the engine itself. The present invention is directed to~ard an improvement to the invention described and claimed in the aforementioned patent.
It is therefore an object of this invention to provide a blade retaining assembly which permits ready assembly and disassembly of the blades of a rotor disc element.
It is another object of the present invention to proyide a blade retaining assembly which is positively locked in position whereby vibrations due to engine operations are ineffectiye to cause undesirable removal of the assembly.
Briefly stated these and other objects which will become apparent from the following detailed description and accompanying drawings are accomplished by the present inyention which in one form provides a split-nut locking assembly for attachment to a groove wherein the split-nut includes a collar having two arcuate segments each having threaded portions spaced from each other by a minor diametrical distance between peaks of opposed threads on each of said segment. The split-nut further includes an undercut adjacent said threaded portions, the undercut having a diameter greater than the a~orementioned minor diameter. A
wrenching set screw having a deformable portion is disposed in a first mode wherein the deformable portion has a first diameter less than the minor diameter. The deformable portion is deformable to a second diameter greater than the minor diameter.
~hile the specification concludes with claims distinctly claiming and particularly pointing out the ~P2,~æ~
invention described herein, it is believed that the invention will be more readily understood by reference to the discussion below and the accompanying drawings in which:
FIG. 1 is a perspective view showing the locking assembly of this invention as assembled within a portion of a rotor disc.
FIG. 2 is an exploded perspective view showing the locking assem~ly of FIG. 1 in combination with a portion of a rotor disc.
FIG. 3 is a cross-sectional view showing a split-nut disposed within the rotor groove.
FIG. 4 is a cross-sectional view of FIG. 1 taken along the line 5-5 with the wrenching set screw only partially inserted.
FIG. 5 is a cross~sectional view of FIG. 4 with the wrenching set screw fully inserted.
FIG, 1 shows a portion of a rotor assembly 10 of the type commonly includes in an axial flow compressor which may form an integral part o~ a gas turbine engine. The rotor assembly 10 is shown as including a rotor disc 11 having axially spaced apart, opposed faces 12 and 14, both of which are substantially normal to the axis of rotor rotation.
The rotor disc 11 includes a plurality of circumfexentially spaced apart blade 22 and 24 disposed about its periphery. The blades 24 are end locking blades specially adapted to acc~mmodate the split nut blade locking assembly of this inYention shown generally at 37 and which will hereinafter be described in full detail. Each of the blades 22, 24 includes an airfoil vane section 26 between which gas 3~ flow may be directed for compression in a manner well known to the art. The blades 22, 24 also include platforms 28, 30 respectively from which dovetail root portions 32 extends substantially inward in the radial direction. The platforms 28 and 30 generally overhang the root portions 32.
The blades 22, 24 are radially and axially retained by means of a circumferential dovetail groove 16 extending around the outer periphery of the rotor disc 11. The dovetail groove 16 includes a pair of side walls 18 which are undercut to provide inwardly directed abutment faces 20. Each dovetail root portion 32 is thickened at the inner radial end to provide outwardly extending shoulders 34 which abut the inwardly directed faces 20 of the dovetail groove, thereby radially retaining the blades under centrifugal loading.
Referring now to FIG. 2, the circumferential dovetail groove 16 includes a circular entrance slot 36 therein, to accommodate insertion of the individual blade root portions 32 into the dovetail groove 16. Each blade root portion 32 is individually inserted through the circular entrance slot 36 for engagement with the opposing surfaces of the dovetail groove 16. After insertion each blade 22 is circumferentially slid around the dovetail groove 16 into platform abutting
2~ relation with an adjacent blade until all the inserted blades circumferentially fill the dovetail groove. The last two blades to be inserted are the end locking blades 24.
Again re~erring to FIÇ. 2 there is shown the last inserted locking blade 24 adjacent within the circular entrance slot 36 and aligned for sliding engagement with the dovetail groove 16. As may be readily observed, the circular entrance slot 36 is of su~ficiently large radius to accommodate insertion o~ the substantially rectangular cross-sectional root portion 32 o~ the end locking blade 24. The root portions of the conyentional blades 22 are identical to the root portions of the end locking blades 24, and are inserted into the entrance slot for engagement with the dovetail groove in like manner. All of the root portions 32 include opposing transverse faces 35, 35' extending across the dovetail groove.
The opposing transverse faces 35, 35' generally lie in the plane of intersection of a rotor radius with the central axis of rotation, and are normal to the side walls 18 of the circumferential dovetail groove 16. The opposing transverse faces 35, 35' however, are not inherently limited to any particular plane and may be skewed in relation to the side walls 18 of the dovetail groove 16.
The split-nut loc~ing assembly is also shown in FIG. 2 at 37 as including aSplit nut 38 and an internal wrenching set screw 46. A sacrificial washer 33 is disposed at the bottom of entrance slot 36 for purposes hereinafter to be described. The split-nut 38 includes a split collar 39 haviny two arcuate segments 40, 40'. Outside surfaces 41, 41' of arcuate segments 40, 4QI respectively are proportioned for abutting en~agement with the inside surfaces of the circular entrance slot 36. Arcuate segments 40, 40' of the split collar 39 respectively include flange members 43, 43' respectively. The flange members 43, 43' respectively have outwardly extending shoulders 44, 44' for engagement with the inwardly directed abutment faces 20 of the sidewalls 18 of the doYetail grooves 16. The ends of the flange members 43, 43' cooperate together to form split transverse abutment faces 54, 54'. Arcuate segments 40~ 40' include internal enlarged recesses or undercuts 58, 58' respectively disposed immediately adjacent internal threaded portion 56, 56', respectively.
~n one form of the in~ention undercuts 58, 58' extend to the same depth as the ma~or diameter of the threads in internal portion 56, 56'.
The arcuate segments 40, 40' includes internal screw thread portions 56, 56' adapted to threadably engage ~8~
external screw thread 57 of the wrenching set screw 46. Set screw 46 includes a conically shaped deformable portion 60 extending from thread portion 57 at one end thereof. Relief slot 62 is disposed in deformable portion 60 so as to promote deformation of portion 60 in manner hereinafter to be described. Portion 60 further includes a generally conical surface 64 which terminates at outer edge 66 remote from thread pxtion 57.
As yiewed in FIG. 3 thread portions 56 and 56l are sho~n in alignment and have a minor diameter "a" and a major diameter "b". Minor diameter "a" is the diameter taken across threaded portions 56 and 56' at the peaks of the thread teeth while major dlameter "b" is the diameter taken across threaded portions 56 and 56' at the valleys of the threads teeth.
Additionally, undercut 58 is sho~n in this preferred embodiment to h.ave a diameter greater than minor diameter "a~
and substantially equal to major diameter "b".
Deformable portion 60 is disposed in an undeformed state or mode wherein the diameter of edge 66 is slightly less 2Q than the mlnor d~ameter "a". Disposed in this mode set screw 46 may be threadably inserted between segments 40 and 40' with.out interference between edge 66 and thread portions 56 and 56' of split collar 39.
In order to lock the blades into fixed position on the ci~cumference of the rotor disc 11 after all the blades ha~e been inserted into the groove, the split-nut 38 is inserted into the area of the circular entrance slot 36 and dovetail groo~e 16 in a manner so that the outer surfaces 41, 41' o~ the arcuate segments of the split collar 39 abut the interior sur~aces of th.e circular entrance slot and each outwardly extending shoulder 44, 44' engages a corresponding inwardly directed abutment face 20 of the dovetail groove 16.
-- 6- ~
~ ~8~
The split-transverse abutment faces 35, 35' engage the respectlve transverse faces 35, 35' of the root portions 32 of the locking blades 24. The split halves of the nut 38 are spread apart and maintained in abutting and engaging relation with the dovetail groove 16 by insertion of wrenching set screw 46 which engages the split nut 38.
With reference to FIGS. 4 and 5, the self-locking features of the present invention will now be described.
FIG. 4 exhibits a cross-sectional view of set screw 46 partially inserted between the split halves of nut 38. In this position, set screw 46 has been inserted until edge 66 abuttingly engages sacrificial washer 33 which serves to prevent edge 66 of set screw 46 from scratching the bottom of dovetail groove 16 as set screw 46 is rotated. Additionally, as shown in FIG. 4, conical deformable portion 60 is disposed in a first or undeformed mode wherein the diameter of edge 66 is slightly less than the minor diameter "a" of thread portions 56 and 56l. Consequently, during insertion edge 66 did not interfer with internal screw threads 56 and 56' or split nut 38.
Referring to FIG~ 5, further tightening of set screw 45 causes ed~e portion 66 to move tightly, engage sacrifical washer 33. This wrenching action causes de$ormable portion 60 to spread to a de$ormed mode wherein the diameter of edge ~` 66 expands to a second diameter greater than the minor diameter "a". In this mode then edge 66 fills undercuts 58 and 58' to overlap threaded portions 56 and 56'. In this ; manner then set screw 46 is prevented by the interference of edge 66 with threaded portions 56 and 56' from undesirable egress which might be otherwise caused by vibration during
Again re~erring to FIÇ. 2 there is shown the last inserted locking blade 24 adjacent within the circular entrance slot 36 and aligned for sliding engagement with the dovetail groove 16. As may be readily observed, the circular entrance slot 36 is of su~ficiently large radius to accommodate insertion o~ the substantially rectangular cross-sectional root portion 32 o~ the end locking blade 24. The root portions of the conyentional blades 22 are identical to the root portions of the end locking blades 24, and are inserted into the entrance slot for engagement with the dovetail groove in like manner. All of the root portions 32 include opposing transverse faces 35, 35' extending across the dovetail groove.
The opposing transverse faces 35, 35' generally lie in the plane of intersection of a rotor radius with the central axis of rotation, and are normal to the side walls 18 of the circumferential dovetail groove 16. The opposing transverse faces 35, 35' however, are not inherently limited to any particular plane and may be skewed in relation to the side walls 18 of the dovetail groove 16.
The split-nut loc~ing assembly is also shown in FIG. 2 at 37 as including aSplit nut 38 and an internal wrenching set screw 46. A sacrificial washer 33 is disposed at the bottom of entrance slot 36 for purposes hereinafter to be described. The split-nut 38 includes a split collar 39 haviny two arcuate segments 40, 40'. Outside surfaces 41, 41' of arcuate segments 40, 4QI respectively are proportioned for abutting en~agement with the inside surfaces of the circular entrance slot 36. Arcuate segments 40, 40' of the split collar 39 respectively include flange members 43, 43' respectively. The flange members 43, 43' respectively have outwardly extending shoulders 44, 44' for engagement with the inwardly directed abutment faces 20 of the sidewalls 18 of the doYetail grooves 16. The ends of the flange members 43, 43' cooperate together to form split transverse abutment faces 54, 54'. Arcuate segments 40~ 40' include internal enlarged recesses or undercuts 58, 58' respectively disposed immediately adjacent internal threaded portion 56, 56', respectively.
~n one form of the in~ention undercuts 58, 58' extend to the same depth as the ma~or diameter of the threads in internal portion 56, 56'.
The arcuate segments 40, 40' includes internal screw thread portions 56, 56' adapted to threadably engage ~8~
external screw thread 57 of the wrenching set screw 46. Set screw 46 includes a conically shaped deformable portion 60 extending from thread portion 57 at one end thereof. Relief slot 62 is disposed in deformable portion 60 so as to promote deformation of portion 60 in manner hereinafter to be described. Portion 60 further includes a generally conical surface 64 which terminates at outer edge 66 remote from thread pxtion 57.
As yiewed in FIG. 3 thread portions 56 and 56l are sho~n in alignment and have a minor diameter "a" and a major diameter "b". Minor diameter "a" is the diameter taken across threaded portions 56 and 56' at the peaks of the thread teeth while major dlameter "b" is the diameter taken across threaded portions 56 and 56' at the valleys of the threads teeth.
Additionally, undercut 58 is sho~n in this preferred embodiment to h.ave a diameter greater than minor diameter "a~
and substantially equal to major diameter "b".
Deformable portion 60 is disposed in an undeformed state or mode wherein the diameter of edge 66 is slightly less 2Q than the mlnor d~ameter "a". Disposed in this mode set screw 46 may be threadably inserted between segments 40 and 40' with.out interference between edge 66 and thread portions 56 and 56' of split collar 39.
In order to lock the blades into fixed position on the ci~cumference of the rotor disc 11 after all the blades ha~e been inserted into the groove, the split-nut 38 is inserted into the area of the circular entrance slot 36 and dovetail groo~e 16 in a manner so that the outer surfaces 41, 41' o~ the arcuate segments of the split collar 39 abut the interior sur~aces of th.e circular entrance slot and each outwardly extending shoulder 44, 44' engages a corresponding inwardly directed abutment face 20 of the dovetail groove 16.
-- 6- ~
~ ~8~
The split-transverse abutment faces 35, 35' engage the respectlve transverse faces 35, 35' of the root portions 32 of the locking blades 24. The split halves of the nut 38 are spread apart and maintained in abutting and engaging relation with the dovetail groove 16 by insertion of wrenching set screw 46 which engages the split nut 38.
With reference to FIGS. 4 and 5, the self-locking features of the present invention will now be described.
FIG. 4 exhibits a cross-sectional view of set screw 46 partially inserted between the split halves of nut 38. In this position, set screw 46 has been inserted until edge 66 abuttingly engages sacrificial washer 33 which serves to prevent edge 66 of set screw 46 from scratching the bottom of dovetail groove 16 as set screw 46 is rotated. Additionally, as shown in FIG. 4, conical deformable portion 60 is disposed in a first or undeformed mode wherein the diameter of edge 66 is slightly less than the minor diameter "a" of thread portions 56 and 56l. Consequently, during insertion edge 66 did not interfer with internal screw threads 56 and 56' or split nut 38.
Referring to FIG~ 5, further tightening of set screw 45 causes ed~e portion 66 to move tightly, engage sacrifical washer 33. This wrenching action causes de$ormable portion 60 to spread to a de$ormed mode wherein the diameter of edge ~` 66 expands to a second diameter greater than the minor diameter "a". In this mode then edge 66 fills undercuts 58 and 58' to overlap threaded portions 56 and 56'. In this ; manner then set screw 46 is prevented by the interference of edge 66 with threaded portions 56 and 56' from undesirable egress which might be otherwise caused by vibration during
3~ operation of the engine.
Removal of set screw 46 may be accomplished simply by turning the screw 46 in the opposite direction. The torque applied to the set screw will cause threaded portion ~6 and 56' to cut into edge portion 66 so as to form external threads thereon whereby set screw 46 may be easily withdrawn.
While a preferred embodiment of the present invention has been depicted and described, it will be appreciated by those skilled in the art that modifications, substitutions and changes may be made thereto without deviating from the scope of the invention as set forth in the appended claims .
Removal of set screw 46 may be accomplished simply by turning the screw 46 in the opposite direction. The torque applied to the set screw will cause threaded portion ~6 and 56' to cut into edge portion 66 so as to form external threads thereon whereby set screw 46 may be easily withdrawn.
While a preferred embodiment of the present invention has been depicted and described, it will be appreciated by those skilled in the art that modifications, substitutions and changes may be made thereto without deviating from the scope of the invention as set forth in the appended claims .
Claims (5)
1. A split-nut locking assembly for attachment to a groove comprising:
a split-nut including a split collar having two arcuate segments, said segments having threaded portions spaced from each other by a minor diametrical distance between the peaks of opposed threads on each of said segments, said split-nut having an undercut adjacent said threaded portions, said undercut having a diameter greater than said minor diameter;
and a wrenching set screw compatible with said split-nut and including a dependent conically-shaped deformable portion terminating at a base edge having a first diameter not greater than said minor diameter but being deformable to a second diameter greater than said minor diameter.
a split-nut including a split collar having two arcuate segments, said segments having threaded portions spaced from each other by a minor diametrical distance between the peaks of opposed threads on each of said segments, said split-nut having an undercut adjacent said threaded portions, said undercut having a diameter greater than said minor diameter;
and a wrenching set screw compatible with said split-nut and including a dependent conically-shaped deformable portion terminating at a base edge having a first diameter not greater than said minor diameter but being deformable to a second diameter greater than said minor diameter.
2. The invention as set forth in claim 1 wherein said deformable portion includes a relief slot for promoting deformation of said deformable portion.
3. The invention as set forth in claim 2 further comprising:
a sacrificial element disposed in said groove, said deformable portion adapted to abuttingly engage said sacrificial element.
a sacrificial element disposed in said groove, said deformable portion adapted to abuttingly engage said sacrificial element.
4. A split-nut locking assembly for attachment to a groove comprising:
a wrenching set screw having an external screw thread portion and a conically-shaped deformable portion extending from said external screw thread portion, and a split-nut including a split collar having two arcuate segments the inside surfaces of which are threaded for threadably engaging said external thread portion of said set screw, said threaded inside surfaces having a minor diameter, said arcuate segments integrally connected to flange members having sides which extend outwardly into shoulders adapted for engagement with the side walls of the groove when the said set screw is threadably engaged within the split-nut so as to spread apart the halves of the split-nut, said conically-shaped deformable portion disposed in a first mode wherein said deformable portion has a first diameter less than said minor diameter, said deformable portion being deformable to a second position wherein said deformable portion has a second diameter greater than said minor diameter.
a wrenching set screw having an external screw thread portion and a conically-shaped deformable portion extending from said external screw thread portion, and a split-nut including a split collar having two arcuate segments the inside surfaces of which are threaded for threadably engaging said external thread portion of said set screw, said threaded inside surfaces having a minor diameter, said arcuate segments integrally connected to flange members having sides which extend outwardly into shoulders adapted for engagement with the side walls of the groove when the said set screw is threadably engaged within the split-nut so as to spread apart the halves of the split-nut, said conically-shaped deformable portion disposed in a first mode wherein said deformable portion has a first diameter less than said minor diameter, said deformable portion being deformable to a second position wherein said deformable portion has a second diameter greater than said minor diameter.
5. The invention as set forth in claim 4 wherein said deformable portion includes a relief slot for promoting deformation of said deformable portion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US93790778A | 1978-08-29 | 1978-08-29 | |
| US937,907 | 1978-08-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1128869A true CA1128869A (en) | 1982-08-03 |
Family
ID=25470549
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA333,491A Expired CA1128869A (en) | 1978-08-29 | 1979-08-09 | Positive locking split-nut blade retaining assembly |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5549508A (en) |
| AU (1) | AU4816179A (en) |
| CA (1) | CA1128869A (en) |
| DE (1) | DE2934298A1 (en) |
| IL (1) | IL57560A0 (en) |
| IT (1) | IT1122868B (en) |
| SE (1) | SE7907160L (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58192462A (en) * | 1982-05-04 | 1983-11-09 | Matsushita Electric Ind Co Ltd | Linear motor |
| JPS61295858A (en) * | 1985-06-24 | 1986-12-26 | Matsushita Electric Works Ltd | Linear pulse motor |
| EP1803899A1 (en) * | 2006-01-02 | 2007-07-04 | Siemens Aktiengesellschaft | Blade locking assembly for a turbomachine |
| EP1803900A1 (en) * | 2006-01-02 | 2007-07-04 | Siemens Aktiengesellschaft | Closure unit for the remaining space between the first and the last blades of a bladed ring inserted in a circumferencial slot of a turbomachine, and corresponding turbomachine |
| US8523529B2 (en) * | 2009-11-11 | 2013-09-03 | General Electric Company | Locking spacer assembly for a circumferential entry airfoil attachment system |
| FR2971541B1 (en) * | 2011-02-16 | 2013-03-22 | Snecma | AUTON CIRCONFERENTIAL BLOCKING DEVICE FOR TURBOMACHINE WITH RADIAL DEPLOYMENT BY DEPLIING A U |
| US9127563B2 (en) * | 2011-04-05 | 2015-09-08 | General Electric Company | Locking device arrangement for a rotating bladed stage |
-
1979
- 1979-06-14 IL IL57560A patent/IL57560A0/en unknown
- 1979-06-19 AU AU48161/79A patent/AU4816179A/en not_active Abandoned
- 1979-08-09 CA CA333,491A patent/CA1128869A/en not_active Expired
- 1979-08-21 IT IT25256/79A patent/IT1122868B/en active
- 1979-08-24 DE DE19792934298 patent/DE2934298A1/en not_active Withdrawn
- 1979-08-28 JP JP10870079A patent/JPS5549508A/en active Pending
- 1979-08-28 SE SE7907160A patent/SE7907160L/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| SE7907160L (en) | 1980-03-01 |
| IT1122868B (en) | 1986-04-30 |
| JPS5549508A (en) | 1980-04-10 |
| IL57560A0 (en) | 1979-10-31 |
| IT7925256A0 (en) | 1979-08-21 |
| DE2934298A1 (en) | 1980-03-13 |
| AU4816179A (en) | 1980-03-06 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |