US3039739A

US3039739A - Pinned blade connecting means

Info

Publication number: US3039739A
Application number: US776926A
Authority: US
Inventors: Frank G Leland
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1958-11-28
Filing date: 1958-11-28
Publication date: 1962-06-19
Anticipated expiration: 1979-06-19
Also published as: GB870643A

Description

June 19, 1962 F. G. LELAND 3,039,739

PINNED BLADE CONNECTING MEANS Filed Nov. 28, 1958 IN VEN TOR.

United States This invention relates to a pinned connecting means.

More specifically, this invention relates to a retaining means for preventing axial movement of pins used to connect the blades to the rotor wheels in a gas turbine engine compressor or turbine assembly. The invention accomplishes this by providing a distortable ring engaging the individual pins for each blade connection to retain the pins in an axial position.

It is therefore the object of this invention to provide an axial retaining means for the pins in a pinned blade connection of a turbine or compressor rotor and blade assembly.

Other features, advantages and objects will become apparent by reference to the detafled description of the invention and to the drawings wherein the preferred embodiment of this invention is illustrated.

In the drawings:

FIGURES l and 2 are enlarged perspective cross-sectional views of portions of a rotor assembly embodying this invention in diiferent stages of assembly,

FIGURE 3 is a side elevational view of a detail,

FIGURE 4 is a perspective view of another detail, and

FIGURE 5 is a cross-sectional view on a reduced scale of a portion of a rotor assembly embodying this invention.

Referring now to the drawings, and more particularly to FIGURE 5, there is shown therein schematically a portion of a rotor wheel assembly 10, which may be for use in either a compressor or turbine as a matter of choice, having a plurality ofabutting blade assemblies 12 circumferentially surrounding a rotor 14 and secured thereto by means to be described constituting the subject of this invention.

Referring more particularly to FIGURES 1 and 2, it will be seen that each of the blade assemblies 12 includes a blade 16 having a platform 18 and two axially spaced tangs or flanges 29 depending therefrom so as to straddle the rim portion 22 of rotor 14 in a known manner, the abutting blade platforms 18 as shown providing a sub stantially continuous circumferential surface around the rotor. While two tangs are provided for straddling the single rotor rim portion 22, it will be clear that this assembly could be reversed to provide a rim on the rotor straddling a single tang depending from the platform without departing from the scope of the invention.

Referring now to the connecting means for joining the blades to the rotor, each of the tangs 20 has a hole 24 axially aligned with a hole 26 provided in the rotor rim 22 for the slideable insertion therein of a pin 28 for connectin g the blade to the rotor wheel.

Insertion of pin 28 into the

holes

24 and 26 prevents radial movement of the tangs with respect to the rotor, and the enlarged head 30 of the pin prevents axial movement of the pin in one direction; however, some means must be provided for preventing axial movement of the pin in the opposite direction, which will now be described.

Each of the blade platforms has an upstream edge 32 overhanging the tangs 20 and is circumferentially milled to provide a circumferentially extending slot 34 between the edges of the tang and the platform for receiving therein the radially outermost portion of a retaining ring 36 of L-shaped cross-section. The ring 36 may be of sheet metal of a thickness slightly less than the thickness of slot 34 and flanged at its radially inner portion as shown tent ice

to conform to the radial and axial contours of the tangs 20 as seen in FIGURE 2. Ring 36 is furthermore partially segmented by a number of slots 38- and 40 and connecting apertures or openings 42 and 44 to provide circumferentially separated flexible finger portions for a purpose to be described, the, apertures or holes 42 being of a size slightly greater than the diameter of the body 46 of the pin 28, equal in number to the number of holes in the tangs and rotor, and having the same circumferential spacing as that of the rotor and tang apertures. The holes 42, however, are spaced a slightly greater radial distance from the rotor axis than the rotor and tang holes so as to be radially misaligned with respect to the other apertures in the normal position of the retaining ring 36 as shown in FIGURE 3, which position prevents entry of the end of the pin 28 into the holes 42, while, however, fitting the outermost radial portion of the ring into the slot 34 and the flanged or bent portion 47 surrounding and abutting the end of the tang 20.

To align the holes 42 with the

holes

24 and 26, to thereby permit the insertion of the pins 28 therethrough, a camming wrench 48, provided with dowels 50 spaced apart a distance equal to the distance between adjacent holes 44 of the ring 36, is inserted into holes 44 to deform the ring in a manner to be described. The slots 38 and 40 permit deformation of the retaining ring as shown in FIGURE 1, where the edge 32 of the platform has been removed for clarity, by the arcuate movement of the edges 52 and 54 of adjacent segments towards each other upon a radially inward force being applied to the ring in hole 44, thereby moving hole 42 radially inwardly until it is aligned with 26 and 24 upon rotational movement of the camming wrench. Cooperating with the retaining ring, the pin 28 is provided at its one end with an annular notch 56 of a width slightly greater than the thickness of the retaining ring 36. As will be evident, therefore, the insertion of the camming pins or dowels 50 of the carnrning wrench into the holes 44, and turning of the wrench in one direction or the other will cam the retaining ring to the position shown in FIGURE 1 axially aligning the

holes

42, 26 and 24 and permitting the insertion therein of the pins 28 therethrough, whereupon the notch 56 is aligned with the retaining ring aperture 42. Release of the camming wrench 48 to its original unstressed position returns the retaining ring segments to their undeformed or original positions with the portion of the retaining ring defined by the outline of the aperture 42 entering the notch '56 in the pin and therefore axially retaining the pin from movement.

While the assembly of the rotor will be clear from a consideration of FIGURES 1 and 2, a brief rsum of this assembly is as follows: first, the platforms of the individual blade assemblies 12 with their tangs 20 are hooked over the edge of the retaining ring 36 with the edge of the ring in the slots 34-; secondly, the retaining ring and blade segments are straddled over the rim portion 22 of the rotor wheel with the

holes

26 and 24 aligned; thirdly, the pins 28 are inserted through the holes into abutment with the retaining ring 36; tourthly, the carnming wrench 48 is inserted into adjacent apertures 44 of the camrning ring 36, and the cannning wrench is forced clockwise or counterclockwise to axially align the holes 42 with the

apertures

26 and 24 so that the pins 28 may be inserted into the holes 42 with notches 56 aligned with the retaining ring; fifthly, the camming wrench is released or returned to its original position returning the retaining ring 36 in its undistorted original shape causing the ring to enter the pin notch 56 thereby retaining the pin from axial movement. The assembly could alternately be made without departing from the scope of the invention by initially abutting the portion 47 of the retaining ring 3 against the rotor rim portion 22 and dropping the blade assembly with its tangs 20 into the slot created until the platform is engaged with the ring 36, and then proceeding as described.

From the foregoing it will therefore be seen that the invention provides a simple, inexpensive and efiicient means for axially retaining and locating the pins used to connect the blades to a rotor in a gas turbine compressor or turbine assembly. While the invention has been illustrated in its preferred embodiments in FIGURES 1-5 in connection with a gas turbine engine compressor or turbine, it will be obvious to those skilled in the art that many modifications can be made thereto without departing from the scope of the invention.

I claim:

l. A rotor assembly comprising, in combination, an apertured rotor, an apertured blade member, a pin insertable through said rotor and blade member apertures upon alignment thereof, and an annular deformable pin retaining element engaging and cooperating with said blade member and rotor and pin and having an aperture therein normally misaligned with said rotor and blade member apertures in its normal undeformed shape preventing insertion of said pin through said rotor and blade member and element apertures, deformation of said element aligning said apertures for the insertion of said pin there- 'thr'ough, and means on said pin and element engageable ,upon the return of said element to its normal undeformed shape securing said pin against axial movement relative to said element.

2. A rotor assembly comprising, in combination, an apertured rotor, a plurality of apertured blade elements adapted to be secured thereto, a plurality of pin means for securing said elements to said rotor, and means to secure said pin means against relative axial movement with respect to said rotor and blade elements, the apertures of each of said elements and said rotor being axially aligned for the insertion therethrough of said pin means, said means to secure said pin means comprising an annular deformable member abutting said blade elements and rotor and having a plurality of apertures therein adjacent to and normally misaligned with the blade element and rotor apertures preventing the insertion of said pin means through said blade element and rotor and member apertures, said annular deformable member being deformable to a shape axially aligning its apertures with the apertures in said rotor and blade elements for the insertion therethrough of said pin means, and means on said pin means and deformable member engagea-ble upon return of said member to its undeformed shape preventing axial movement of said pin means relative to said member.

3. A rotor assembly comprising, in combination, an apertured rotor, an apertured blade assembly adapted to be secured to said rotor, a pin insertable through said apertures upon the axial alignment thereof with each other for securing said rotor and blade assembly together, and a pin retainer therefor comprising a deformable annular apentured resilient plate adapted to abut one edge of said blade assembly and rotor in the assembled position of said rotor and blade assembly and plate, said pin being insertable through the apertures of said plate, said plate in its normal undeformed position having portions thereof blocking entry of said pin through said plate apertures, said plate being deformable to a shape and position removing said portions from blocking position and aligning said plate apertures and said rotor and blade assembly apertures for the insertion of said pin therethrough, the resiliency of said plate returning said plate to its normal undeformed shape and position, and means on said pin and said plate engagea-ble upon return of said plate to its normal position preventing axial relative movement of said pin.

4. A rotor assembly comprising, in combination, an apertured rotor, a blade assembly having an apertured tang portion depending therefrom, a pin insertable through said apertures upon axial alignment thereof for securing said blade assembly to said rotor, and a pin locating and retaining member comprising a deformable annular apertured resilient plate abutting said blade assembly and rotor upon assembly of said member, blade assembly and rotor, the apertures of said plate being adjacent to and normally misaligned with said tang portion and rotor apertures to normally prevent entry of said pin through said rotor and tang portion and member apertures, said plate including a plurality of relatively movable portions normally blocking the movement of said pin through said element apertures and movable to other positions upon deformation of said plate to align said apertures permitting the insertion therethrough of said pin, the resiliency of said plate returning said plate to its normal undeformed shape, and means on said pin and said plate engageable after insertion of said pin through said apertures and upon return of said plate to its undeformed shape for locking said pin against axial movement relative to said plate.

5. A rotor assembly as in claim 3, wherein said plate portions comprise a plurality of normally separated resilient finger portions, adjacent finger portions being apertured to together define said plate apertures therein and therebetvveen, the deformation of said plate moving the finger portions to change the position of said plate apertures to align them with the rotor and blade assembly apertures.

6. A rotor assembly as in claim 3, 'wherein the periphery of said pin retaining plate is radially notched at circumferentially spaced locations to provide normally separated resilient finger portions constituting said pin blocking portions, adjacent finger portions being slotted to together define said plate apertures therein and therebetween, the deformation of said plate circumferentially moving the finger portions to change the position of said plate apertures to align them with the rotor and blade assembly apertures.

7. A rotor assembly as in claim 3, wherein the periphcry of said pin retaining plate is radially notched at circumferentially spaced locations to provide normally separated resilient finger portions constituting said pin blocking portions, adjacent edges of said finger portions being oppositely slotted to together define said plate apertures therein and therebetween, the deformation of said plate moving the adjacent finger portions to change their relative circumferential positions to align said plate apertures with the rotor and blade assembly apertures.

8. A rotor assembly as in claim 3, wherein said pin retaining plate portions comprise a plurality of arcuately movable normally separated resilient finger portions, adjacent edges of said finger portions being apertured to together define said plate apertures therein and therebetween, the deformation of said plate arcuately moving the adjacent finger portions to change the position of said plate apertures to align them with the rotor and blade assembly apertures.

9. A rotor assembly as in claim 8, wherein said engageable means on said pin and said plate comprises a groove in said pin adapted to receive a portion of said plate therein to prevent relative axial movement therebetween after insertion of said pin through said plate aperture and the return of said finger portions to their normally separated positions.

10. A rotor assembly as in claim 9, wherein said plate finger portions in the deformed position of said plate are withdrawn from said groove to permit the insertion or withdrawal of said pin from said plate aperture.

11. A rotor assembly as in claim 3, wherein said blade assembly has means thereon cooperating with said plate in its normal undeformed shape securing said plate against axial movement relative thereto.

12. A rotor assembly as in claim 11, wherin said last mentioned means comprises a groove adapted to receive the periphery of said plate portions therein in the normal undeformed shape of said plate, the deformation of said plate withdrawing said portions from said groove permitting the axial movement of said plate relative to said assembly.

13. A rotor assembly as in claim 9, wherein said blade assembly has means thereon cooperating with said plate in its normal undeformed shape securing said plate against axial movement relative thereto.

14. A rotor assembly as in claim 13, wherein said last mentioned means comprises a groove adapted to receive the periphery of said plate portions therein in the normal undeformed shape of said plate, the deformation of said plate Withdrawing said portions from said blade assembly and pin groove permitting the axial movement or" said plate relative to said assembly.

References tilted in the file of this patent UNITED STATES PATENTS 2,559,131 Oestrich July 3, 1951 FOREIGN PATENTS 745,073 Great Britain Feb. 22, 1956 1,136,390 France Dec. 29, 1956