MXPA01003253A - Shim removing tool and method - Google Patents

Abstract

A tool for removing a shim from a dovetail of a fan blade for a turbine engine rotor includes a clip and a handle. The clip includes a release edge configured to engage a flared lip of a dovetail shim. The handle extends from the clip and contacts the exterior surface of the shim. When the handle and the clip are rotated about a longitudinal axis of the handle, the release edge separates the flared lip of the shim from the dovetail and the handle applies a downward force to easily remove the shim from the dovetail.

Description

TOOL AND METHOD TO REMOVE WEDGES DECLARATION OF GOVERNMENT RIGHTS The government of the United States has rights in this invention in accordance with contract No. F33657-95-C-0055 issued by the Department of the Air Force.

BACKGROUND OF THE INVENTION This invention relates generally to tools and, more particularly, to a tool for removing a wedge from a stage 2 fan blade for an aircraft engine rotor. Gas turbine engines typically include a multistage axial flow high pressure compressor, which supplies high pressure air to a combustor, and a high pressure turbine downstream from the combustor. The compressor and the turbine include multiple stages, and each stage includes a stationary member referred to as a stator and a rotational member referred to as a rotor. A "stage 2" turbine stage includes a plurality of fan blades attached to and extending radially from a fan disk. Each paddle includes a thin wing and a dovetail that is fixed in a dovetail slot on a fan disc surface. Dovetail wedges are used to provide a proper fit between the dovetail and the dovetail slot. The thin wings extend from the grooves of the dovetail in a radial direction with respect to a central axis of the turbine engine, and define a flow path for the combustion gases. During maintenance and repair, removal of a dovetail wedge from a stage 2 fan blade is difficult. Due to the dovetail shape, conventional tools are not well equipped for the removal of dovetail wedges. In this way, removing a wedge from a dovetail is usually difficult and time consuming. Therefore, it may be desirable to provide a non-expensive tool that facilitates the quick and easy removal of dovetail wedges from stage 2 fan blades without damaging the dovetails.

COMPENDIUM OF THE INVENTION In an illustrative embodiment of the invention, a tool for removing a dovetail wedge from the blade of a rotor fan disc includes a fastener and a handle. The fastener includes a base and opposite sides extending from the base. A release edge is located at one end of a side and is configured to be located between the dovetail and the wedge. The handle is configured to be placed between opposing sides of the fastener and cooperates with the release edge to remove a dovetail wedge from the dovetail when the handle and fastener are rotated together about a shaft of the handle. More specifically, the wooden handle has a longitudinal axis and a substantially square transverse shape. The handle is inserted between the opposite sides of the fastener and extends from the fastener so that the longitudinal axis of the handle is substantially parallel to the longitudinal axis of the sides of the fastener. The tool is positioned so that the release edge is engaged with a lip of the dovetail wedge, and the handle contacts the outer surface of the wedge. When the handle and the fastener are rotated about the axis of the handle, the release edge separates the wedge lip from the dovetail, and the handle applies a frictional force to the outside of the wedge which facilitates the removal of the wedge without damage the dovetail.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a partially assembled aircraft fan rotor; Figure 2 is a perspective view of a fan blade; Figure 3 is a perspective view of a wedge used to secure the fan blade shown in Figure 2 to the rotor shown in Figure 1; Figure 4 is a side elevation view of one embodiment of a tool for removing the wedge shown in Figure 3 of the fan blade shown in Figure 2; Figure 5 is a front elevation view of the tool shown in Figure 4; Figure 6 is an illustration of the tool shown in Figure 4 during use; Figure 7 is a partial side view of the tool shown in Figure 4 positioned to remove a wedge from the pallet; Figure 8 is a partial side view of the tool and vane shown in Figure 7 after the tool has been turned slightly; and Figure 9 is a side elevational view of an alternative embodiment of a wedge removal tool.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 is a perspective view of a portion of a stage 2 fan rotor 20 for a turbine engine (not shown). The rotor 20 includes a fan disc 22 including a plurality of dovetail grooves 24. A fan blade 26 is inserted into each dovetail groove 24, so that the blade 26 extends radially from a central axis 28. of the rotor 20. The disk 22 further includes a front flange 30 and a paddle retaining ring 32. Figure 2 is a perspective view of the fan blade 26 including a thin wing 34, a platform 36 and a dovetail 38. The platform 36 is inclined relative to a bottom 40 of the dovetail 38. The thin wing 34 extends above the platform 36, includes a tip handle 42 and is aerodynamically configured to direct the combustion gases to through the rotor 20 (shown in Figure 1). The dovetail 38 extends below the platform 36 and includes an upper portion 44 of substantially constant width and a rounded lower portion 46 including a maximum width near a lower portion mid section and a decreased width above and below of its middle section. The dovetail 38 further includes a pair of side surfaces 48 that include a pressure face 50 extending substantially parallel to the bottom 40 of the dovetail and between the midsection of the lower portion of the dovetail and the upper portion 44 of the dovetail. An aluminum-bronze coating is applied to the pressure face 50 of the dovetail. Figure 3 shows a wedge 52 of the dovetail configured to be inserted in the lower portion 46 of the dovetail (shown in Figure 2). The wedge 52 of the dovetail includes top flares 54 having side walls curved outward, i.e., convex towards a central axis 56 of the wedge 52, and a lower portion 58 having inwardly curved side walls, i.e., concave with respect to the central axis 56. The wedge 52 is generally configured as an hourglass with an open top. In addition, the wedge 52 includes an inner surface 60 and an outer surface 62. The inner surface 60 includes a pressing face 64 and the upper flares 54 include flared lips 66. After the wedge 52 is installed in the dovetail 38 , the pressure face 64 makes contact with the pressure face 50 of the dovetail and the upper flares 54 are separated through the upper portion 44 of the dovetail (shown in Figure 2). Figures 4 and 5 are side elevation and front elevation views, respectively, of a tool 68 for removing the wedge 52 from the dovetail (shown in Figure 3) of the dovetail 38 (shown in Figure 2) ). The tool 68 includes a fastener 70 including a first short side 72, a second long side 74 and a base 76. The long side 74 extends a greater distance from the base 76 than does the short side 74. The long side 74 includes an adjacent base 76 to the first end 78 and a second end 80. A cable handle 82 extends from, and is connected to the second end 80. The short side 72 includes an adjacent base 76 to the first end 84 and a second end 86 including a release edge 88. Opposite sides 72 and 74 form a channel 90 therebetween having an inner surface 92. In an alternative embodiment, the fastener 70 is continuously curved or spiral. In a further alternative embodiment, the fastener 70 includes three sides substantially perpendicular to each other and a fourth side having a release edge. A substantially square handle 94 is configured to be inserted into the channel 90 of the tool 68. The handle 94 includes a longitudinal axis 96 and is positioned in the channel 90 so that the longitudinal axis 96 is substantially parallel to the long side 74. In addition, an outer surface 98 of the square handle 94 is embedded in the long side 74, makes contact with the base 76 and is separated from the second side and the release edge 88. A portion of the handle 94 exits from the channel 90 and the handle 94 it occupies only a portion of the channel 90. In an alternative embodiment, the handle 94 has a partially curved cross section. In a further alternative embodiment, the handle 94 has a cross section with two or more sides of unequal length, such as a generally triangular or rectangular transverse shape. Figure 6 illustrates the removal of the wedge 52 from the dovetail 38 using the tool 68. The tool 68 is shown in an orientation to the right. The handle 94 extends from the fastener 70 to the right as the fastener is viewed from the long side 74. The handle 94 is grasped with a right hand 100 and a thumb 102 is placed on the fastener 70, holding in this manner the handle 94 appropriately positioned with respect to the fastener 70. The fan blade 26 is held in the left hand 104 and the fastener 70 and the handle 94 are rotated together counterclockwise about the longitudinal axis 96 of the handle 94 to remove the wedge from the dovetail 38. In an alternative embodiment, the tool 68 has a left-hand orientation and the handle 94 extends to the left as the fastener 70 is viewed from the long side 74. The tool 68 is grasped with the left hand 104, and the paddle 26 is in the right hand 100. In a further alternative embodiment, the handle 94 is fixed to the fastener 70. Figures 7 and 8 illustrate, with greater detail e, the removal of the wedge 52 by turning the tool 68, which has the orientation to the right. The release edge 88 of the fastener 70 is brought into contact with the enlarged lip 66 of the wedge 52, and the outer surface 98 of the handle 94 is brought into contact with the outer surface 62 of the wedge 52. The rotation of the handle 94 and the fastener 70 about the handle longitudinal axis 96 (shown in Figure 8) separates the enlarged lip 66 from the dovetail pressing face 50 and pulls the wedge 52 from the dovetail 38. Meanwhile, the outer surface 98 of the handle 94 pushes the outer surface 62 of the wedge 52, and the wedge 52 slides from the lower dovetail portion 46. In this way, the wedge 52 is removed quickly and easily, and damage to both the dovetail 38 and the wedge 52 is prevented. Figure 9 illustrates an alternative orientation of the tool 68. The handle 94 is rotated approximately 90 ° around the fastener 70, so that the longitudinal axis 96 is parallel to the long side 74 of the fastener 70, but is transverse to the base 76 and the short side 72, so that the longitudinal axis 96 crosses the interior surface 92 of the 90 channel fastener. Tool 68 has the orientation on the right. The handle 94 is grasped with the right hand (not shown) with the thumb placed on the wire handle 82. The release edge 88 is engaged with the flared lip 66 of the wedge (shown in Figure 7) and pressure is applied to the handle 94 towards the wedge 52, that is, to the left in Figure 9, causing the fastener 70 to rotate and separate the wedge 52 from the dovetail 38 (shown in Figure 8). In an alternative embodiment, the tool 68 is used in a left hand orientation by positioning the tool 68 and the handle 94 as a mirror image of Figure 9. The fastener 70 is fabricated from a spring steel fastener binder of 2.54 cm capacity such as a fastener in accordance with Federal Supply Service Manufacturing No. AC072100 or a Large Binder Bracket No. 10220 manufactured by United Stationers Supply Company of Des Plaines, Illinois, and sold under the trade name of UNIVERSAL . One side of the binder fastener is cut to form the short side 72 extending to 0.635 cm measured perpendicular from the base 76. The stiff ends of the short side 72 are polished and then sharpened with stone to form the release edge 88. A 1.905 cm square piece of non-metallic material, such as wood, is cut to a length of approximately 17.78 cm to form the handle 94, and the exterior of the handle 94 is beveled and smoothed with an abrasive cloth. The wire handle 82 can be removed from the long side 74 of the fastener 70 or used to facilitate the positioning of the handle 94 within the fastener 70. The tool 68 is inexpensive, simple to manufacture, and simple to use. Since the fastener 70 is made of carbon steel, the tool 68 is reliable since the fastener 70 will not weaken after repeated use. A worker can easily and quickly remove dovetail wedges from a full set of forty-six fan blades while using the tool 68. Damage to both the dovetail 38 and the wedge 52 is prevented. In this way, considerable time and expense is saved in the maintenance and repair of aircraft. Although the invention has been described in terms of several specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.

Claims (20)

1. - A tool for removing a dovetail wedge from a rotor fan blade paddle, the paddle including a dovetail, the wedge including an outer surface and first and second pressure faces attached to the dovetail portion , each of the pressure faces having a flared lip extending therefrom, the tool comprising a fastener comprising a base and opposing sides extending from the base, and a release edge at one end of a side to be located between the dovetail and wedge.

2. A tool according to claim 1, wherein one of the sides extends a greater distance from the base than the other side.

3. A tool according to claim 1, wherein the release edge is separated from the opposite side.

4. A tool according to claim 1, further comprising a handle configured to be positioned so as to extend from the inner surface of the fastener.

5. A tool according to claim 4, wherein the handle includes a longitudinal axis, the fastener comprises a channel and the axis of the handle extends through said channel.

6. A tool according to claim 5, wherein the handle partially fills the channel.

7. - A tool according to claim 6, wherein the handle has a substantially square cross section.

8. A tool according to claim 7, wherein the handle comprises a non-metallic material.

9. A tool according to claim 4, wherein the handle is fixed to the channel.

10. A tool for removing a dovetail wedge from a rotor fan blade paddle, the paddle including in a dovetail portion, the wedge including on an outer surface and first and second pressure faces fastened to the dovetail portion, each of the pressure faces having a flared lip extending therefrom, the tool comprising a fastener comprising a side and a release edge configured to make contact with the flared lip as said side it is rotated around an external axis to the side.

11. A tool according to claim 10, wherein the fastener comprises a second releasably releasable side of the release edge.

12. A tool according to claim 11, wherein the fastener comprises metal.

13. A tool according to claim 12, wherein the fastener further comprises a cable handle connected to the second side.

14. - A tool according to claim 10, further comprising a handle of substantially square cross section.

15. A tool according to claim 14, wherein the handle is fixed to the fastener.

16. A tool according to claim 14, wherein the longitudinal axis of the handle is transverse to the side of the fastener.

17. A method for removing a dovetail wedge from a rotor fan blade paddle with a tool, the paddle includes in a thin wing portion and a dovetail portion, the wedge including an outer surface and first and second pressure faces fastened to the dovetail portion, each of the pressure faces having a flared lip extending therefrom, the tool including a fastener having a release edge configured to couple the flared lip to the wedge, and the handle inserted into, and extending from the fastener, the handle detached from the release edge and having a longitudinal axis, the method comprises the steps of: inserting the release handle of the fastener between the enlarged lip of the wedge and the dovetail; and rotating the handle about the longitudinal axis of the handle, so that the handle tangentially makes contact with the outer surface of the wedge and the release edge separates a pressure face from the wedge of the dovetail.

18. A method according to claim 17, wherein the fastener further includes an interior surface, the method further comprising the step of: extending the fastener handle so that the axis extends through the fastener substantially parallel to the surface.

19. A method according to claim 17, wherein the fastener further comprises an interior surface, the method further comprising the steps of: pivoting the handle around the fastener, so that the longitudinal axis of the handle is transverse to the surface of the bra; grab the handle; and push the handle towards the dovetail.

20. A method according to claim 19, wherein the method further comprises the steps of: holding the pallet with a first hand; place the thumb of a second hand on the tool holder; and grasp the handle with the rest of the second hand.