US1073987A - Blade-securing means. - Google Patents

Description

F. HODGKINSON.

BLADE SECURING MEANS.

APPLIOATIOH 21mm JULY 24, 1911.

Patented Sept. 23, 1913.

IN VE'NTOR.

ceive the blade root. The packing pieces STATES PATENT OFFICE. rnANcIs HoneKINs oN, or nncnwoon PARK, PE NSYLVANIA, ASSIGNOR T0 ma WESTINGHOUSE MACHINE coMrANY, A CORPORATION on PENNSYLVANIA.

BLADE-SECURING MEANS;

Specifloation ofLetters Patent. Application filed July 24, 1911. Serial No. 640,250.

Patented Sept. 23, 1913.

To all whom it may concern.

Be it known that I, FRANCIS HODGKINSON, a subject of the King of Great Britain and Ireland, and a resident of Edgewood Park, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Blade- Securing Means, of which the following is a specification.

This invention relates to. turbines, and particularly to means for securing the bases or roots of blades to the blade carrying elements.

As is well known, turbine blades are subjected to considerable centrifugal force due to the high rotative speed at which they operate, and in certain types of blades, particularly those usually employed in connection with turbines of the Parsons type, the centrifugal force upon the blades is liable to cause them to become loose and, mani; festly, a loose blade in a turbine is a very serious menace to the rest of the blades.

It is one 'of the objects of my invention to provide a blade-securing means, which will efficiently hold the blades in place and prevent their becoming loose in the actual operation of the turbine.

In carrying out my invention, I preferably construct the blade of a stri of metal, drawn to blade shape, and provi e a lip or foot at one end thereof, which may be formed by a die and bulldozer by upsetting the end of the blade. The u set root or foot of the blade is considerably stronger than the bent over portion would be for, manifestly, the upsetting of the blade root forces the molecules of the metal close to.- gether, and the'roots may be made of any desired thiclmesses. The blade root is preferably of less width than the width of the blade, so that it may fit into a groove in the wall'of the ordinary turbine blade receiving groove. 1 V

The thickness of the root is referably that of the height of'the wall 0? the supplemental groove, so, that the packing pieces may rest firmly upon the floor of the groove and over the root of the blade, so that it will not be necessary to weaken the packing pieces by cutting out portions thereof to reare preferably inserted in undercut portions "in the turbine grooves, so that a tendency of a longitudinal bodily movement of the blade will not displace the packing piece, but will be resisted successfully thereby.

In the drawings forming a art of this specification: Figure 1 IS a ragmentary perspective view of a portion of a bladeholding element as, for example, a rotor to which the blades and packing pieces are secured. Fig. 2 is a cross-sectional view through a portion of a row of blades and blade-holding element. Fig. 3 is a detailed perspective view of one of the blades. Fig. 4 is a detailed perspective view of one of the packing pieces. Fig. 5 is a top view of a row of blades in place; Fig. 6 is a sectional view on line 60 of Fig. 5; and Fig. 7 is a sectional view on the line 77 of Fig. 5 with some blades in place.

Referring now to the drawings b numerals of reference, 10 designates a ladeholding element provided with a groove 11, inwhich is a subjacent groove 12 in the floor thereof. The sides of the groove 11 are preferably inclined as at 13 and 14, and to provide undercut ortions for the respective packin pieces to e interposed between the respective blades. The blade is best illustrated in Fig. 3. It is shown as comprising the portion 15 having a foot or root 16 at one end thereof, which foot may be formed by being die struck in a bulldozer, so as to upset the metal. In actual practice the upsetting of the end of the blade may extend entirely across the blade, but portions of the root or foot may be cut away so that said foot may benarrower than the width of the blade. v

In the practical application of the blade it may be found desirable to have the foot of space 18 is provided between the bottom of the root and the floor of the groove 12 to allow for contraction and-expansion of the root due to difi'erence in temperatures.

After the blade is put in place a packing piece 19 may be inserted, which is of greater within the undercut portion ofthe groove,

width than the width of the an, 15, and which has an inclined portion 20 fitting 11 formed by the side wall 13. The opposite side of the packing piece is similarly inclined, as indicated at 21, to be received in the undercut portion 14; ofthe groove 11. The packing piece 19 may be provided with a shoulder l9 so that the blade may fit against the curved portion 19 while that portion beyond the shoulder l9 may fit into .the groove 14. The blades and packing packing piece. The packing pieces cannotbe removed in a radial direction because the r two nclined sides engage mundercut portions of the slot or groove in which they are secured.

If it becomes necessary to remove any blade or a number of bladesfrom the groove 11, the, lip 24E may be cut offer bent back so that the wedge 23 can beremoved, then, the wedge 24 can be removed and packing pieces and blades may beslid along until they'are adjacent the cutaway portion, when they may be readily taken out. New blades The packing pieces and packing pieces may be then inserted, and after the groove 11 is filled, the wedges 24 and 23 may be inserted, and by bending over the lip 24?, as indicated in Fig. 7, all of the blades and packing pieces place.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention together with the device which I now consider to represent the best embodiment thereof, but I desire to have it understood that the device shown is only illustrative and that the invention can be carried out in other ways.

Having thus described my invention, what I claim is: I

In combination with a. grooved bladeholding element having a groove in the floor of the first named groove, a removable blade will be held in having a projection at right angles with its body portion and in the second mentioned groove, apacking piece in the first mentioned groove and beneath which the projection on the blade extends, and wedges on the side of the blade and packing piece for holding the packing piece in the groove.

In testimony whereof, I have hereunto subscribed my name this 18th day of July, 1911.

I FRANCIS HODGKINSON. Witnesses:

,B. B. HINES, B. F. FUNK.

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