US1539574A - Turbine-blade fastening - Google Patents

Description

Q ITNE ill lgrz. INVENTOR May 26, 1925. 1,539,574

A. T. KASLEY TURBINE BLADE FASTENING Filed April 18, 1922 ATTORNEY Patented May 26, 1925.

UNITED STATES ALEXANBEB '1. KASLEY, OF ESSINGTON,

PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTBIC AND MANUFACTURING cOMlANY, .A. COBPOBATION OF PENN- SYLVANIA.

TURBINE-BLADE FASTENING.

Application filed April 18, 1922. Serial No. 554,890.

To all whom it may concern:

Be it known that I, ALEXANDER T. KAS- mar, a citizen of the United States, and a resident of Essington, in the county of Delaware and State of Pennsylvania, have invented a new and useful Improvement in T urbine-Blade Fastenings, of which the following is a specification.

My invention relates to turbine blading, and more particularly to fastening means therefor, and it has for its object to provide apparatus of the character designated which shall be simple in construction, which shall be capable of ready insertion and removal, and which shall insure a tight joint between a blade root and a turbine rotor.

Apparatus embodying the features of my invention is illustrated on the accompanying drawings, forming a part of this application, in which: Fig. 1 is a sectional detail view showing a turbine blade with my improved fastening means applied thereto; Fig. 2 is a sectional view taken along the line II II of Fig. 1. and Figs. 3 and 4 are detail views showing different forms of fastening wedge elements, Fig. 3 showing a convenient means for removing wedges.

In my application, Serial l86,517, filed July 19, 1921, assigned to the lVestinghouse Electric & Manufacturing Company, there is disclosed and claimed blading of the wide exhaust type adapted to receive steam laterally and to discharge it peripherally or at the tips. Owing to the extreme Width of blading of this type, it is necessary to provide longitudinal slots in the rotor to receive the blade roots. In my application, Serial No. 527 ,674, filed January 7 1922, also assigned to the Westinghouse Electric & Manufacturing Company, I disclose and claim a dove-tail type of .connection between the roots of the blading of the type referred to and the rotor; and, in order to secure a tight fit between the elements of each joint,

' key means are provided to be driven in between the bottom of the root portion of each blade and the bottom of the root-receiving slot.

My present invention relates to an improved form of wedge or key mechanism to be interposed between the root of each blade and the bottom of its corresponding slot in order to insure that the dovetail surfaces on the sides of the root and at the sides of the slot shall be maintained in contact, The

wedging or keying means for each blade comprises a plurality of upper and lower wedge elements contacting alternately and in series, and adapted to be forced in position between the bottom of a slot and the bottom surface of a blade root in order to maintain the inclined surfaces of a root and a slot firmly in contact.

Referring now to the drawings for a more detailed description of my invention, I show a turbine blade 10 of the wide type having a dovetail root portion 11 adapted to it in a dovetail slot 12 provided in the turbine rotor 13. A countersunk slot or groove 14 is provided at the bottom of the dovetail slot 12 to receive the wedging means which serve to force the inclined surfaces of the dovetail root portion 11 tightly into contact.

tail connection tight preferably comprises a series of upper and lower wedge elements 16 and 17, respectively, which contact 'alternately with the bottom of the root portion 11 and with the bottom of the slot 14. The wedge blocks 16 and 17 are preferably similar and interchangeable. The wedgeelements 16 and 17 have cooperating inclined surfaces 18 and 19, respectively. After a blade 10 is inserted in a slot, a bottom wedge 17 is then placed at the back end of the slot and a top wedge 16 is then inserted between the bottom wedge and the bottom of the root portion 11 and is then drivenin position, the cooperating inclined surfaces 18 and 19 insuring that the upper surface of the wedge block 16 shall cooperate with the root portion 11 in order to secure a tight fit of the dovetail connection. Thereafter, succeeding blocks 17 and 16 are inserted in the same manner, each block 16 being driven tightly in place in the manner and for the purpose stated. After all of the blocks are inserted,

a suitable end plate member 20 is secured in position with respect to the rotor 13 by any suitable means, the end plate member being adapted to contact with the last wedge 16 of each series in order to hold said Wedges in position.

Any suitable means may be used in order to insure that each of the last wedge blocks 16 shall contact with the plate 20, for example, I show set screws 21 which are adapted to be adjusted for this purpose.

Lit)

The lastblock .16 may. also be maintained in positionfimerely by properly adjusting the tap screws 23 shown for holding the plate on the rotor 13. If the latter mode of holding the last blocks is resorted to, tl1en such'blocks may be ground or shims may be provided in order to insure firmpontact ,between the blocks and the blade.

In order to assure ready removalof then blocks 16 and 17 when it is desired to remove a;blade, ;the. top; series ofblocks 16 may be; providedwiththreaded openings to receive thescrew threaded:end 26,0f a tool-27 which may -be.-inserted in the slot 14 for; thepurpose of pulling outeach of. the top wedge blocks-16. In Figure l, I "show a modified. form of-weclge-blwkr116 ,providejd {with a T-head portion 28 which-may beengaged bya hook, pinchers;,-;or the, like, for. removal.

From the! foregoing, .itwill be;apparent. that Ihave devised wedging mechanisn'i for use inyconnectionwi th a dovetail =j ointwhich shall insure-that the :members of such-joint shallcat all times .;be lrrraintained firmly in, contact,-. the, edging mechanism being par: ticulairlyauseful; for maintaining ,tl1e= dove-i tailroot portionof wide turbine blades firn1-; ly in contact with w correspondingly \formed slots-inra rotors,

While I have shown my invention in but one .form, it will.- bewobvious; to those skilled in itheart-that itfis-notl so limited, but :is susceptibleof various, other changes and modifications-,\vitlioutdeparting vfrom the spirit thereof, and I desire, therefore, that ,0111) such limitations shall beeplaced thereupon as: arepimposedby thepriorart or-asare specifically set forth 'in-theappended claims;

What- 1 claim is. 1

1. The combination swith a turbinea rotor; a 1 having a :plurality of longitudinal slots .withi; outwardly. converging sideszand blades having 3 Y complementally formed {root portions fittingatheslots', ofia plurality of ruedgerl blockscontacting .;in series and. alternatelywith the bottoms of each slot and its corre-.- spondingybladc root .portionand means carried bythe (blocks havingtheirithick ends" disposed towardthe outer endzofdtlie rotoru slot ,twhereby=the-ablolcks may be; readily T81 moved. i

2.2.Th'e combination with a a :turbine. rotor h aving a plurality .OI" longitudinal; slots-with outward-1y converging sides andblades haw-.-

fitting 'rthfi i slots, 5 of, :a pluralityg of, wedge means carried by the blocks having their thick ends disposed toward the outerend of the rotor slot adapted to connect wi tli a suitable retracting tool when it isdesired to remove the wedge blocks.

3.;In aturbine,.t he combination of a rotor having a plurality of longitudinal slots with outwardly converging sides, each j of "said 4 slots being closedat one endi'flnd open; at the oppositeendlforrthe lIlSBItlQIbOfblflCh-ES therein a plurality of blades having complementally formed; root portions fitting into said slots,,-a1plurality of; wedge blocks contacting in series and. alternately ,with the bottoms of each slot and its corresponding blade rootportion, ;and1means.;.coacting with the blades 1 and the rotor :for, preventing lat-; eralimovementiof the blades in the Sl0liS.e3

4. Ina turbine, the combinationlota rotor; having a plurality of longitudinal slots with outwardly converging i sides, each of. said slots being closed at oneiendandiopenjat the t opposite end. for ithewinsertion: of blades 1 therein, a plurality of blades having ,com plementally formed root; portions fitting ,into i said I slots, a plurality of: wedge iblocks; .con 85 tacting lllg SGI'lQS and alternately with? he!" bottomsofieachslot and its corresponding blade root portion, andan end plate secured. to .1 ,the a rotor ;and bearing; against :the sides otthe blades .for preventingol iteralmoves 0 ments ofzthe blades in the. slots.

5: In a turbine, the combination of arotor}, liavingiaplural-ity of longitudinalislots with; outwardly converging .lside'sy; each nofi 5 said slots being closed at one endiand openat the; 95 opposite end.;for thetinsertioen1;of blades,-; therei-n, a plurality ofr'blades having;complementallyv formed. root pertions fitting into said slots arpluralit of WBdgBblQClISuCOIHw tacting ,in seriesv and alternately .with theo bottomsiofleach-slot and-itsrcorrespondingr. blildGTOOtJPOltlOH, amend plate secured to therotor and bearing against the sides ofu the blades for preventinglateral movements ofgthebladesin thes1ots,;:and means assov; 105 ciated :with the end plates afar-holding saidI wedge blocks, in ,place.

In testimony whereof I 5 have hereunto; subscribed my name this =17,th day of April 1922.; ingg complemcntally 1 :formed; 5 root: portions

Images