US972411A

US972411A - Blade-holding means.

Info

Publication number: US972411A
Application number: US42907708A
Authority: US
Inventors: Charles E Sweet
Original assignee: Westinghouse Machine Co
Current assignee: Westinghouse Machine Co
Priority date: 1908-04-24
Filing date: 1908-04-24
Publication date: 1910-10-11
Anticipated expiration: 1927-10-11

Description

' WITNESSES.-

0. E. SWEET. BLADE HOLDING MEANS.

- APPLICATION FILED APR. 24,1908. 972,41 1 Patented Oct. 11,1910.

2 SHEETS- SHEET l.

A ORNEY IN FACT.

c. E. SWEET. BLADE HOLDING MEANS.

APPLIOATION FILED APB.24, 1908. I

Patented Oct. 11,1910.

32 I nmiiiii UNITED STATES PATENT OFFICE.

CHARLES E. SWEET, 0F WILKINSBURG, PENNSYLVANIA, ASSIGNOB TO THE WESTING- HOUSE MACHINE COMPANY, A CORPORATION GF PENNSYLVANIA.

BLADE-HOLDING MEANS.

To all whom it may concern:

Be it known that I, CHARLES E. SWEET, a citizen of the United States, and a resident of \Vilkinsburg, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Blade Holding Means, of which the following is a specification.

This invention relates to elastic fluid turbines and more particularly to blading for such turbines.

Various methods are employed in the manufacture of turbines for securing the stationary and moving blades to the bladecarrying elements of the turbines, for the reason that various kinds, weights and sizes of blades are utilized in turbines and also because these various kinds of blades encounter different strains, which tend to dislodge them from the mounting elements.

My invention relates specifically, although I do not wish to so limit it, to blades which are secured by means of separate calking or spacing pieces into grooves or slots formed in the blmle-carrying elements of the turbine.

Blades have heretofore been secured into grooves, formed in the blade-carrying elements and provided with either straight or undercut walls, by means of separate spacing or calking pieces which are inserted between the base portions of adjacent blades and expanded transversely, and thereby caused to grip both the walls of the mounting slot and the faces of the adjacent blade bases.

The object of my invention is the production of a simple means for securing the blades to the blade-carrying element, which will effectively resist the dislodging strains due to centrifugal force and encountered by the moving blades. This and other objects I attain in the embodiment of my invention herein described and illustrated.

In the drawings accompanying this application, and forming a part thereof: Figure 1 is a fragmental sectional elevation of a blade-carrying element shown in connection with means for securing the last few blades of a row; Fig. 2 is a longitudinal section along the line AA of Fig. 3 and illustrates an embodiment of my invention; Fig. 3 is a plan view of blades mounted in accordance with my invention; Fig. 4 is an end elevation of a calking and spacing piece forming Specification of Letters Patent.

Application filed April 24, 1908.

Patented Oct. 11, 1910.

Serial No. 429,077.

I a detail of my invention; Fig. 5 is a perspective view of a blade which forms a detail of my invention; Fig. 6 is a fragmental section of a blade-carrying element and illustrates, in connection with means for mounting the last few blades of a row, a modification of my invention; Fig. 7 is a plan view of Fig. 6; Fig. 8 is a section along the line B-B of Fig. 7; and, Fig. 9 is a perspective view of a detail of my invention.

Referring particularly to Sheet 1 of the drawings: the blade-carrying element 10, which term is used to include both the stationary casing and the rotating spindle of the turbine, is provided with undercut slots 11, which extend circnmferentially of the element with respect to the axis of the turbine. The bases of blades 12 are inserted into the slots 11 and each blade is provided at its mounting end with a slot 13, which extends transversely across its convex face. Separate calking pieces 15 are mounted between the bases of adjacent blades and each piece is so constructed that one of its end faces is concave and conforms in contour to the convex faces of the blades while the other face is convex and conforms in contour to the concave faces of the blades; it being understood that the contours of the respective faces of the blades mounted in one slot are substantially the same and that each blade is of substantially the same crosssection throughout its length.

The lateral faces of each spacing piece 15 are inclined to conform with the inclination of the lateral faces of the mounting slot 11 and consequently each piece fits more or less snugly within the slot between two adjacent blades.

A transversely-extending hole 17 is provided in each calking piece 15 and is so located in the piece as to cut the concave face of the piece which corresponds in contour to the convex face of the blades, and to there expose a pin 18, which is either loosely or securely mounted in the hole 15. The hole 15 is also so located in the piece that the exposed portion of the pin 18 is adapted to cooperate with the slot 13 out in the convex face of the next adjacent blade and to positively lock the blade and the piece together after they are mounted in the mounting slot 11.

The blades are mounted in the slot 11 by first calking one of the calking pieces 15 into place, then introducing the base portion of a blade into the slot adjacent to the calking piece and then securing the blade in place by driving a second calking piece home against the blade and calking it in place within the slot. Alternate blades and calking pieces are thus introduced into the slot and the calking operation continued until all but two or three of the blades are secured in the slot. It is impossible to insert the last few calking pieces and blades into the slot 11 because of its undercut walls and because of the shape of the calking pieces. For this reason I cut away a portion of the undercut wall of each slot and replace it by a removable piece which may be secured to the blade-carrying element of the turbine in any suitable manner.

In Fig. 1 and also in Figs. 6,7 and 8, I illustrate means for mounting the last few blades in a row. A portion of one wall of each of two adjacent slots 11 is removed by drilling or otherwise cutting away a portion of the blade-carrying element and the cutaway portion is replaced by the substantially cylindrical piece 20 (Fig. 1), which is secured to the blade-carrying element by a screw 21 and which is shown machined to replace the cut-away portion of the undercut walls of the two adjacent slots. Vith such an arrangement the last few blades and call:- ing pieces are placed in the slot and then secured in place by firmly securing the piece 20 to the element 10.

IVhen the blades and calking pieces are secured in place, the calking pieces are positively held in 'place by the undercut walls of the slot 11 and also by the frictional contact with these walls, and the bases of the blades are secured both by the frictional contact of the calking pieces against the blade bases and by the cooperating pins 18 and slots 18, which positively lock the adjacent blades and calking' pieces together.

On Sheet 2 of the drawings I have shown a modification of my invention. The mounting slots 11 formed in the blade-carrying element 10 are not undercut as in Fig. 1 but have straight walls and each wall is provided with a slot 22 of a semi-circular crosssection and extends longitudinally of the slot 11. A wire 23 is located in each slot 22 and extends longitudinally of the slot 11. These wires take the place of the undercut walls of the slot 11 of Fig. 1, previously described, and are utilized as a locking means for positively securing the calking pieces and also the blades into the mounting slot.

Each calking piece 24 is so formed that one end face corresponds in contour with the convex faces of the blades 12 and the other corresponds with the concave faces of the blades. A pin 25 is located in a hole 26, which extends transversely through-the calking piece and which is so located relative to mean the piece that it cuts the concave face and there exposes the pin 25. A slot 27 is cut across the convex face of each blade 12 near' its mounting end and is adapted to cooperate with the exposed portion of the pin 25 of the next adjacent calking piece to positively lock the blade and the calking piece together after they are secured in the slot 11. A slot 28 extends across each lateral face of the calking pieces 24 and each blade is provided with a notch 29,cut in each lateral edge. which, with the slots 28 of the calking pieces, are adapted to cooperate with the slots 22 formed in the walls of the slots 11 in holding the wires 23 in place when the blades are secured to the mounting element. lVitb such a construction the wires 23 cooperate with the slots 28 and the notches 29 to positively secure the pieces 2-1-v and the blades 12 in place in the slots 11.

In mounting the blades one callting piece is located in the slot in the proper position to secure the wires 23 in place in the slots 22. The piece is then secured in place by call ing or by expanding it transversely, thereby causing it to grip the sides of the slot. The base of a blade is then introduced into the slot, adjacent to the piece which has been calked in place, and a second calking piece is driven home against the base of the blade, and is, after the wires are in position in the slots 28, calked into place and caused to grip the walls of the slot and the adiacent face of the base of the blade. The calking action also forces the base of the blade into gripping contact with the first calking piece introduced into the slot. Alternate blades and calking pieces are then introduced into the slot and secured in place in the manner described until all but the last two or three blades are in place.

It would be impossible to insert the last few calking pieces and blades into the slots 11 on account of the wires 23 and for this reason I employ means similar to the means shown in Fig. 1 for securing the last few blades and calking pieces to the mounting element. A portion of the blade-holding element is drilled or otherwise cut away in such a manner as to remove a portion of one wall of each of two adjacent slots 11. A portion of the element so removed is replaced by a piece 30, which is so constructed as to re placed the removed portions of the sides of the slots 11 and is provided with slots 31 which connect the broken ends of the respective slots 22. The last few blades and call:- ing pieces of each row are inserted into their respective mounting slots and then are secured in place by inserting a short section 32 of wire into the

slots

28 and 29 and then securing the piece 30 firmly to the bladecarrying element.

All the calking pieces except the last few are then held in place by the gripping contact caused by the calking and all of them are positively held in place by the cooperating wires and slots. The blades are held in place by the gripping contact between the faces of their bases and the adjacent faces of the calking pieces and each blade is positively locked to an adjacent calking piece by means of the cooperating slots 26 and pins 27, and is positively locked into the slots 11 by means of the cooperating slots 29 and wires 23.

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

lVhat I claim as new and useful and desire to secure by Letters Patent is:

1. In combination in a turbine, a bladeholding element provided with a blade- 1nounting slot, blades mounted in said slot,

- spacing pieces located in the slot between the blades and transversely extending means independent of the blades and spacing pieces for locking each of said blades to an adjacent spacing piece.

2. In combination in a turbine, a bladeholding element provided with a blademounting slot, blades mounted in said slot, spacing pieces located within said slot between the ends of adjacent blades, and transversely extending means independent of the blades and spacing pieces for securing said pieces into said slots and said blades to said pieces.

3. In combination in a turbine, a bladeholding element provided with a blademounting slot, a plurality of blades, the base portions of which project into said slot, spacing pieces located in said slot between said blades and means, comprising a slot formed on each of said blades, and a pin mounted on each of said pieces for positively locking each of said blades to an adjacent piece.

4. In combination in a turbine, a bladeholding element, a slot provided in said element, blades, the bases of which are located in said slot, spacing pieces located in said slot between adjacent blades, and transversely extending means independent of the blades and spacing pieces, carried by said spacing pieces, for locking adjacent blades and spacing pieces together.

5. In combination in a turbine, a bladeholding element provided with an undercut blade-mounting slot, a plurality of radiallyextending blades, the bases of which are mounted in said slot, substantially dovetailed spacing pieces secured in said slot between the bases of adjacent blades, and transversely extending means for locking each of said blades to one of the adjacent spacing pieces.

6. A blade-holding element provided with a slot, a plurality of blades in the slot, distance pieces alternating with the blades, and a pin extending transversely through each distance piece and engaging notches in the blades with which said distance piece alternates.

In testimony whereof, I have hereunto subscribed my name this 21st day of April, 1908.

CHARLES E. SWEET.

Witnesses:

CHARLES W. MOGHEE, E. W. MCGALLISTER.-