US2915281A

US2915281A - Stator vane locking key

Info

Publication number: US2915281A
Application number: US663297A
Authority: US
Inventors: Ridley Oscar Earl; Walsh Edward Joseph
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1957-06-03
Filing date: 1957-06-03
Publication date: 1959-12-01
Anticipated expiration: 1976-12-01
Also published as: GB873759A; FR1208240A

Description

Dec- 1, 1959 o. E. RIDLEY m-AL 2,915,281

STATOR VANE LOCKING KEY Filed June 5, 1957 2 Sheets-Sheet l -L` ZW 6 f4 5 i 1 J E 1 4Z im O f 24 2a Dec. l, 1959 o. E. RIDLEY ErAL 2,915,281

sTAToR VANE LOCKING KEY Filed June s, 1957 2 sheets-sheet 2 A rue/vir- United Safes Patent The present invention relates to a stator vane assembly construction for use in'gascompressors or turbines the type used in gas turbo engines.

In -U.S. application No.` 629,075 led by Robert M. Oppenheimer on Dec.l 18, I1956 and assigned to the same assignee as the presentapplication there is described a stator vane assembly in which the stator vanes of each stage are carried by a statorfring made up of two halves. The casing is also made up of two halves and each half ofthe ring is supported in its half of the casing by meansy of cooperating ring land casing rabbets. The splits between the halves of each stator vane ring and the casing lie substantially in the-same plane. `A number of long thin locking strips are used to lock` the half rings against rotation in the casi-ng.

The particular stator vane assembly design described in the above mentioned application is particularly suitable for vusein very small turbo engines of the type described in application Serial No. 548,987- led by G. W. Lawson on November`25, 1955 and assigned to the same assignee as lthis application. It has been found, however, that-V this small engine design doesenot lend 2,915,281 atented Deliby l, 19,5?

rice

it requires a great deal of time thereby making-.manufacture'andmaintenance expensive. Y f' In accordance-with the-*present invention; a' locking mechanism for locking stator -vane rings-agains'trotation in their casing'is provided which Ye'mplo'ys'keys of1 the above mentioned type, in which eachke'y 'has an -interlocking portion movable into interlocking relationship with other interlocking partsvof the mechanism'to'lock it in its proper position at thetime itis-assembled-in that-position so that it cannot fall out into the casing l duringsubsequenti assembly land disassembly of theother parts of the unit, in which thekeys-imspite` oftheir small size can be easilyassembled in they unit without droppin-gv theminto the; casing unit,lin which-improper; assembly of the keys is.- avoided; which simplifies' and reduces the time required for'assembly and disassembly of the unit and which'thereby reduces the cost' of: manufacture' and maintenance. 'This is accomplished without additionalrseparate partssuch asvscrewsfor bolts orthe like.,4 'i.' .1. t.

Briefly stated and in accordance with #one aspectwoff the invention, the 'interlocking part of the key is fmovable into and out of-interlocked.relationship with a cooperating interlocking .part of the ring while such part vof the ringis removed Ifrom its casing segment,`the key. having a portion whichcan be grasped rmly in=the iingers-to move the interlocking part thereof intofand out of such itself to the use of the thin locking strips because with such engines the strips are so thin and small and fragile they are diicult to'handlei and manufacture and-are very easily assembled improperly resulting in damage to the rotor blades and possible failure of the engine.

These locking strips can be eliminated by designing the rings so that the edges of the halves thereof abut against each other with an individual locking key being provided for each casing rabbet and its associated ring rabbet or rabbets. The key is anchored or locked between the abutting edges of the halves of the casing rabbet and is located in aY recess in one of such edges. It extends between the abutting edges of the halves of the lring rabbet or' rabbets supported by' such casing rabbet into a recess in one of such edges 'to vthereby lock the ring halves against rotation in the casing.Y However, the use of such keys in small engines of the type described in the Lawson application presents a problem because the keys are so tiny that it is difficult to assembleI them without dropping them into the casing and theyl are very easily assembled improperly in their recesses. After the keys have been placed in their recesses and before the other half of the casing is moved into place there is nothing to hold them there and they are apt to fall out into the casing, especially when they have not been seated properly in 'the rst place. lFurthermore,

the handling of the required large number of such small,

interlocked relationship. Slidingy 'movement' into as^4 sembledvposition in its casing segment oflsuch 'part-l of the ring with the key interlocked therewith movesfthekey intoA itsproper locking position =withrespecteto they ring and casingnsegment: ,A 'portion-of the casingseg--l ment overlyingtthe keyfwhen it is moved to vthis lposition locks the interlockingfpartsof ythe key and ringagainst moving out. of. v interlocked relationship. Movement of the interlockingI part of the ring out of-its casing segment carries thefy key with it to a'position in which the casingl segmentnoflonger locks together ther interlocking'parts and the key can be grasped byv the lingers and moved out of interlocked relationship with the ring.' 7

`Preferably'the key-.is` provided fwith `a locking=hook whichy comprises its .interlocking parti-andthe ring seg-L ment, has a`1.hookengagingfportion whichteorriprises` itsl interlocking part, s o that: the keyf can. be-'hookedontoV the ring segrrrenty while its :hook engaging portion isfremoved from its casing, segment.:'1he ring'segmentis then slid -intozits'easingfsegmenttand `.t'hegkey'whichl isi hookedato it. is moved withpitinto .the 1properlo'cking position with respect to theedgesfof the ring and casing segments. A portion 'of thecasing. segment overlying the key `when itis moved to .this position locks it inlitsf longer overlies it4 whereupon itr can be unhooked-from the'ring segment. The: above. and' 'others-advantages' lof the 'presente injvention will. be apparent from the` following descriptionvv v andY claims and the accompanying drawings `all=ofv'vhilchv describe by way of illustration only and without'lirriit'a tion'wha't now isconsidered to be a prefe'rred'embdi-'l ment vrof the present invention." I n,

Figi 1isaviewvin'elevation and partly in section y a pa'uftloffth'-e` lower'halfjof'a compressor which lis in construe ontfotheV compressor described in the,abovg mentined Oppenheimer application fand which an embodiment of the locking mechanism of the,presentz invention.,`

`Fis- VA2 is la, .View in perspective similar to.V thatshowiv in Fig. 1 with a lower half ring partially removed from its casing half to expose its ,hook engaging portion and with the key associated with such half ring removed therefrom. v

Fig. 3 is a view similar to Fig. 2 showing the key hooked to the half ring but with the half `ring still partially out of its casing half.

Fig. 4 is a view taken along the line 4-4 of Figx 3.

Fig. 5 is a section taken along the line 5 5 of Fig. 1, showing the key in its assembled position and showing in broken lines a portion of the edge of the top half of the casing and the top half ofthe ring.

Fig. 6 is a view taken along the line 6-6 of Fig. 5. ,Fig.` 7 shows another embodiment of the locking key of; the present invention. u

Fig. 8 is a View similar to Fig. 1 but showing a smaller portion and in which the key of Fig. 7 is installed.

Fig.,9 is a view similar to Fig. 1 showing another Yembodiment of t'hepresent invention.

Referring to the iigures, 2 is a compressor comprising a stator vane casing 4, having an upper half 6 and a lower half 8 joined by means of flanges 10 and bolts12 as shown in Fig. 5, and a rotor 14 comprising a rotor drum 16 and rotor blades 18.

Each of the halves of the casing 4 is made up of a relatively thin semi-cylindrical casing wall .having a plurality of spaced T-shaped rabbets 22 extending radially inwardly thereof and circumferentially therearound. Each T-shaped rabbet comprises a base portion 24 which extends radially inwardly into the narrow stem 26 of the T, which in turn extends into the flange or tongue portions 30 forming the web of the T and extendingat right angles from the stem 26 in opposite axial direction. Each tongue has a radially outwardly facing supporting surface 34 and forms with the stem 26 and the shoulder 32 between 24 and 26, a recess 42 so that each rabbet.

22 has a pair of recesses 42 on opposite sides thereof. j A plurality of4 stages or rows of stator vanes 58 are mounted on a plurality of tiexible halt` rings 60 made of a thin flexible and resilient steel and the ring halves are in turn mounted on the casing halves in spaced relationship with casing wall 20 by means of a pair of otset, semi-annular rabbet portions 64 which are located along opposite sides of each ring 60, each of which comprises a portion 67 extending radially outwardly and a portion 68 extending in an axial direction from portion 67, and which are received in oppositely facing recesses or spaces 42 of adjacent rabbets 22, as shown, with the radially inwardly facing surfaces 69 of the portion 68 thereof engagingand rigidly supported .by the radially outwardly f facing surfaces 34 of the adjacent rabbets 22. The casing rabbet recesses 42 Vare radially wider than the thickness of portion 68 (Fig. 1). Rotor blades 18 extend between adjacent rows of vanes and a chamber 70 is defined by adjacent casing rabbets, the ring located between the adjacent casing rabbets and the inner surface of. shell 20 located between the adjacent casing rabbets.

All. of the above is described in detail in the above mentioned yOppenheimer application.

- In accordance with the present invention the edge 71 of each semi-annular T-shaped casing rabbet 22 inthe lower half of the casing has a recess 72 extending axially thereacross, such recess having a bottom surface, a radially inwardly facing wall 74 and a radially outwardly facing wall 76. V'I'he corresponding edge of the axially extending portion 68 of each ring rabbet also has a cooperating recess 78 therein, having a bottom surfacel 80 and a side wall 82. The depth of the ring rabbet recess 78 is the sarneas the depth of the casing rabbet recess 72 and when the half rings are in assembled'position in the casing half, the recess 72 in the edge of the T-shaped casing rabbet 22 and the recesses 78 in the corresponding edges of the two ring rabbets being supported by such casing rabbet form a single recess deiined by a bottominade up of bottom surface of the casing rabbet recess and the two bottom surfaces 80 of the recesses in the two ring rabbets, a wall 74, a wall 76, a wall 82 of the recess in one ring rabbet and a Wall 82 of the recess in the other ring rabbet. The non-recessed portion 84 of the edge of the lower half 60 of each ring including the edge of portion 67 is flush with the coresponding non-recessed portion 88 of the edge of the lower casing half, the portion 88 also including the non-recessed portion of edge 71 of the casing rabbet.

One of the rabbet portions 68 of the two ring rabbets 64 supported by each casing rabbet 22 has a notch or slot 92 therein spaced from the recess 78 as shown, the portion of 68 between the recess and notch being designated as 94.

Associated with the edge 71 of each T-shaped casing rabbet is a locking key 96 having a locking portion 98 which is received in the recess formed by recess 72 in the edge of the casing rabbet and the two recesses 78 in the edges of the two ring rabbets supported byy such casing rabbet, as shown, and which has a leg 108 extending from the lower surface thereof. The leg 100 in turn extends into a hook or foot 1Q2 which is received in the notch 92 as shown in Figs. 3 to 5. The thickness of portion 98 is the same as the depth of the recesses 72 and 78 so that the top surface of 98 is ush with the

non-recessed edges

84 and 88 of the lower half rings and lower casing half respectively when the lower half rings are in assembled position in their casing half as shown in Figs. 1, 5 and 6.

When the two halves of the casing are bolted together the edges 84 of the lower halves of the rings and edge 88 of the lower casing half abut snugly against the nonf recessed edges 86 of the upper halves of the rings and the non-recessed edge of the upper casing half respectively (see Figs. 5 and 6). The locking portion 98' is held rmly between the bottom surface of the vrecess 72 in the edge of the'lowercasing rabbet half and tho adjacent edge 90 of the other half of the rabbet in the upper casing half, as shown in Figs. 5 and 6. Since the bottom surface of the recess 78 in the edgeof the portion 68 of the lower half of each of the two ring rabbets supported by the casing rabbet abut against the lower surface of portion 98 and the edge 86 of theportion 68 of the upper half of each of such ring rabbets in the upper casing half abut against the upper surface of the portion 98, the half rings are locked against rotation in the casing.

When the two casing halves containing the ring halves assembled therein are removed from each other the locking key 96 cannot fall out of position because of the hook 102 in the notch 92. The engagement of the edge 186 of portion 98 with the Wall 74 of recess 72 and the leg 100 with the shoulder 32 o f the casing rabbet prevents the key from being moved radially loutwardly and consequently prevents the hook 162l from being removed from the notch'92 when the lower half ring'is assembled in the lower casing half as shown.

The key can be removed simply by sliding thelower half ring containing the recess and notch partially out of the casing half to the position shown in Figs. 2, 3`

and 4 whereupon the key can be easily removed bymcre ly moving it in a radially outward direction.

The assembly of the unit is simple, requiring only that one end of each half ring with the vanes attached thereto be inserted into one nend of a space 70 with the rabbets 64 of the ring being inserted `into the oppositely facing recesses 42 of adjacent rabbets 22 whereafter the half ring is slid circumferentially around the recess into the positions shown in Fig. 2. Then the key can be easily grasped by the fingers and slipped into place cn the half ring partially removed from the casing and having the notch by moving it radially inwardly thereby moving the hook 102 into the notch 92 and at the saine time the locking portion 98 into the recess 78, thereby hooking the key on the ring rabbet and interlocking them together, as shown in Figs. 3 and 4. Thereafter the half ring with the locking key hooked thereto is slid all the Way into assembled position in the casing, as shown in Fig. 5, the locking portion 98 moving into locking position in the recess 72 in the edge of the casing rabbet and the recess 78 in the edge of the portion 68 of the other half ring. The key associated with the other edge of the lower half of the casing rabbet 22, shown in Fig. 3, and the other corresponding edges of the lower halves of the ring rabbets supported by such casing rabbet is hooked in the same way to the ring rabbet of the lower half ring shown in assembled position in the casing half -in Fig. 3 while it is partially removed from the other edge of the casing half since'the half ring shown in Fig. 3 partially removed from the casing half cannot be slid out of the other edge of the casing halfonce the key is hooked thereto. Another alternate construction of these other edges is to make them non-recessed, the recesses and notch being provided in the edge of the upper half of the casing rabbet and the corresponding edges of the.

upper halves of the ring rabbets abutting such other edges. However, only one key is needed for each cornplete ring so that it is not essential to provide another key for these other edges. 'After all the half rings and keys are assembled in their casing halves, the two halvesY ber of such tiny discs being held in place only by gravity it will be realized that it is very easy for some of them;

to fall out of their recesses into the casing during assembly, in many cases without the assembler even knowing that it has happened. These loose keys which have fallen into the casing are apt to cause `damage during operation of the compressor and furthermore the particular rings with which they were intended to be associated are not locked against rotation around the casing. Even Aif the assembler is aware that the keys have fallen into the casing it is time consuming to remove them. Furthermore, it is difcult to handle such small parts since there is very little to hold onto and consequently while they are being assembled in their recesses they are prone to slip out of the lingers into the cas-ing. They have to be dropped into the recesses and consequently they are prone to assume improper positions. This also increases the tendency of the small keys to fall into the casing interior.

In accordance with the present invention each key is like a clip or hook and is in effect very easily clipped or hooked on the ring segment in the position shown in Fig. 3. It can be firmly held in the lingers while it is being so hooked or clipped so that the danger of its slipping out of the lingers is reduced. Once -it is hooked or clipped on the ring segment there is very little danger of it falling out during the time it takes to move the ring segment with the key hooked thereto into place in its casing segment. It can be kept in its hooked position on the ring segment very easily merely by the pressure of the finger while the ring segment is being slid into place. Furthermore, the key is always assembled in the proper position in its recess since once it is pushed into the notch and recess it cannot help but be moved into proper position when the ring segment is slid into place. Although it cannot be removed when the ring segment is assembled in its casing half because of the casing recess wall 74 and the shoulder 32 of the casing rabbet it is easily removed by merely sliding par-t of the ring segment from the casing half. It is locked in place by an interlocking of the parts of the key, the ring segment and the casing segment and without anyadditional separate part such as a screw or bolt.

As described in the above mentioned Oppenheimer application the half rings are supported rigidly by the supporting surfaces 34 of the casing rabbets 22 but are 6 spacedfrom the shell 20 of the casing and the shoulders 32 so that they are not rigidly supported against movement in a radially outward direction, the rin-g rabbets being yieldablyheld against the 'radially outwardly fac-A ing supporting surfaces of the casing rabbet rby air presi sure in chambers 70. The keys are so designed that the radially inwardly facing surface of the'leg 100 is Vspaced a sufficient distance from therradially outwardly facing surface 34 of the tongue 30 so that the key`does not interfere with this feature. That is, the sum of the radial thicknesses of the leg and portion 68 of thefring rabbet is less than the radial width of space 42. Further` with respect to the more, the key has some radial play casing rabbet.

The recesses and notches can be located in the top halves of the casing and rings, in which case the keys are clipped or hooked on the top halves of the rings andl the top half of the casing holds the keys in clipped position. Furthermore, the notch can be in the lower half' of the ring and the cooperating ring and casing recesses inthe top halves of the rings and casing, or the casing recess can be in the lower half lof the casing and the" ring recesses and notch in the upper half or vice versa or the casing recess can be in the top casing half, the notch in the top ring half and the ring recesses in the lower ring half. Furthermore, both the adjacent edges of the top andvbottom halves of the rings and casing can be recessed so that the portion 98 is located partly in the recesses in the edges of the top halves `and partly in the recesses in the edges of the bottom halves. The terms bottom and top and upper and lower are used herein only for the purpose of simplifying the description;y and they are not intended to limit the invention in any way because what is Ifbottom and lower becomes top and upper and vice versa whenv the unit is turned upside down. Although a compressor has been described having two halves, thepresent invention is invention in which the locking portion of the key has a` pair of

legs

112 and 114 each of which has a locking hook 116 and 118 respectively and the portion 68 of the ring rabbets of both of the ring halves associated with each casing rabbet have notches similar to notch 92. In such case, in clipping the key in place, both-of these ring halves must be partially removed from the casing half to positions similar to the position occupied by the single partially removed half ring in Fig. 3 whereupon the key is slipped in place by sliding each foot into its notch and the locking portion `98 into the recesses 78 in the edges of the rabbets of both half rings whereafter both rings are pushed into place at the same time and occupy the positions shown in Fig. 8. The locking portion 98 is moved into locking position in recess 72 when the half rings are pushed into place. In such case the key associated with the other adjacent edges of the half rings and casing halves mus-t be clipped to the edges of the top halves of the ring rabbets and the recesses are located in the top halves of the casing and ring rabbets.

Fig. 9 shows a ring and casing construction exactly like that shown in the above mentioned Oppenheimer application in that each ring has two stages of vanes and has a radially outwardly extending steadying rim or rabbet "1-20 intermediate thereof between the two stages of varies. This rim cooperates with a steadying rim or rabbet 122 extending radially kinwardly from the casing shell' bei tween adjacent T-shaped rabbets, all as described in the 7 above mentioned application. In the construction of Fig. 1 these steadying rims or rabbets are omitted. However, this does not affect the operation of the compressor or the locking mechanism of the present invention.

We claim:

l. A stator vane assembly comprising an annular casing made up of at least two casing segments, an annular stator vane ring mounted in said casing, said ring being made up of at least two ring segments, said ring having an annular segmented rabbet, said casing having an annular segmented casing rabbet cooperating in circumferential engagement with the ring rabbet to support said ring in said casing, a looking key having a locking portion located between the adjacent edges of adjacent ring segments and the corresponding adjacent edges of the casing segments containing said ring segments for locking said ring segments against rotation around said casing, said locking key and one of said ring segments having a hook and the other a hook engaging portion for engaging said hook and securing said key on said one of said ring segments and against falling out of locking position with respect to the edge of said ring segment when said ring segment is disassembled from said casing segment, a portion of the casing segment in which said one of said ring segments is located overlying said key when said ring -segment is in assembled position in said casing segment to lock said hook against moving out of engaged relationship with said hook engaging portion.

2. An assembly according to claim 1, said one of said ring segments having said hook engaging portion which comprises a notch therein spaced circumferentially from the edge thereof and said =key having said hook which is receivable in said notch to hold said `key on said ring segment with said locking portion in looking position with respect to the edge of said ring segment, said hook and looking portion of said key being slidable into and out of said notch and said locking position respectively lto hook and unhook said key to and from said ring segment respectively when the portion of said ring segment having said notch is removed from its casing segment.

3. An assembly according to claim 2 wherein each of said casing segments together with its ring segment assembled therein comprises a casing and ring segment assembly, said adjacent edges of said adjacent ring segments and adjacent casing segments abutting against each other when the casing and ring segment assemblies are assembled, a recess in at least one of the abutting edges of the rabbets of adjacent casing segments, a recess in at least one of the corresponding abutting edges of the rabbets of the adjacent ring segments contained in said adjacent casing segments, said locking portion of said key lying in said recesses.

4. A stator vane assembly comprising a casing made up of at least two segments, a stator vane ring in said casing made up of at least two corresponding segments, said ring having an annular ring rabbet, said casing having an annular casing rabbet for cooperating with said ring rabbet to support said ring in said casing, each of said casing segments together with its ring segment assembled therein comprising a casing and ring segment assembly, the adjacent edges of adjacent ring and casing segments abutting against each other when the casing is assembled, a recess in the edge of the casing rabbet of a casing segment and in the corresponding edge of the ring rabbet of a ring segment mounted in said casing segment, a locking key having at least a portion thereof receivable in said recess and fitting snugly between the bottom of the recess and the adjacent edges of the ring and casing rabbets of the adjacent ring and casing segments, a notch in the rabbet of the ring segment having said recess, said notch being spaced circumferentially from said recess in said ring segment, said key having a locking hook extending into said notch to prevent said looking portion of said key from accidentally falling out o'f 'said recess in said ring segment during assembly and disassembly and While the casing and ring segment as# in which said recess and notch are located is moved out of its casing segment, said locking portion of said key being movable with said ring segment while it is hooked thereto, into and out of said recess in said casing rabbet when said portion of said ring segment is moved into and out of said casing segment respectively, a portion of said casing segment which contains said ring segment overlying said key and thereby locking said key against movement of said hook in a radial direction out of said notch when said ring segment is in assembled position in said casing segment, said movement of said locking portion of said key into and out of said casing recess moving said lkey into and out of overlying relationship with said portion of said casing segment respectively.

5. A stator vane assembly comprising an annular casing made up of at least two casing segments, an annular stator vane ring mounted in said casing, said ring being made up of at least two ring segments, said ring having an annular segmented ring rabbet, said casing having an annular segmented casing rabbet for cooperating in circumferential engagement with said ring rabbet to support said ring in said casing, each of said casing segments together with a ring segment assembled therein comprising a casing and ring segment assembly, a locking key formed with a locking portion located in a recess in one of the abutting edges of at least one of the casing rabbet segments and in a recess in a corresponding abutting edge of at least one of the ring rabbet segments, said locking portion cooperating with an abutting edge of an adjacent ring rabbet segment and with an abutting edge of an adjacent casing rabbet segment for locking said ring segments against rotation around said casing, said locking key formed with a hook, a notch spaced circumferentially from said abutting edge formed in one of said ring rabbet segments, such that said locking key is movable into and out of interlocking relationship with said one of said ring rabbet segments when the ring segment associated therewith is disassembled from the correspondfing one of said casing segments, said one of said casing segments securing said locking key against movement relative to said one of said ring rabbet segments when said ring segment associated therewith is assembled with said one of said casing segments.

6. A stator vane assembly comprising an annular casing made up of at least two casing segments, at least two annular stator vane rings mounted in said casing, each of said rings being made up of at least two ring segments, each of said rings having an annular segmented -ring rabbet, said casing having annular segmented casing rabbets for cooperating in circumferential engagement with said ring rabbets to support said rings in said casing, each of said casing segments together with the ring segments assembled therein comprising a casing and ring segment assembly, a locking key formed with a locking portion located in a recess in an edge of at least one of the casing rabbet segments and in a recess in a corresponding edge of at least one of the ring rabbet segments of each of said rings, said locking portion cooperating with an edge of an adjacent ring rabbet segment of each of said rings and with an edge of an adjacent casing rabbet segment for locking said ring segments against rotation around said casing, said locking key formed with at least two hooks, a notch formed in said one of said ring rabbet segments of each of said rings and spaced circumferentially from said edge thereof, such that said locking key is movable into and out of interlocking relationship with said one of said ring rabbet segments of each of said rings when said ring segments are disassembled from a corresponding one 'of said casing segments, 'said one of 'said casing segments securing said locking key against movement relative to said one of said ring segments of each of said rings when said ones of said ring and casing segments are assembled.

Cil

References Cited in the file of this patent UNITED STATES PATENTS Howard Jan. 13, 1953 Wheatley et al Lune 2, 1953 10