Abstract:
A bladed disk assembly device includes a horizontal arm and a fixed vertical pivot bar that is perpendicularly attached to a first end of the horizontal rotating arm via a sliding coupling mechanism. A vibratory impact device is attached to a second end of the horizontal rotating arm and generates a vibrating motion via a power source. An impact shoe is attached to the vibratory impact device and drives a blade into a disk slot.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application discloses subject matter related to copending U.S. patent application entitled, “BLADED DISK ASSEMBLY METHOD AND ROLLER DEVICE”. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to the assembly of bladed disks. More specifically, the present disclosure relates to assembly methods and devices that aid in the installation of shrouded or other high aspect ratio blades in a compressor or turbine disk of aero or land based gas turbine engines. 
     2. Description of Related Art 
     Gas turbine engine blades have roots that are installed into broached slots in the outer diameter of a disk. The blades have a curved airfoil portion extending radially outward from the blade root and longer blades include a shroud on the distal end of the airfoil portion. When the blades are installed in the disk, the shrouds on the ends of the blades interlock with the shrouds of adjacent blades at a z-notch, which increases damping and thereby reduces blade dynamic response. The z-notches also restrict leakage flow around the blades. But, the shrouded blade design makes the blades difficult to install because they are designed to twist when being seated into the broached slots to provide loading on the shroud dampers. 
     The installation of shrouded blades in a disk is traditionally accomplished by manually hammering the roots of each of the blades into the disk with a non metallic mallet. The roots of the blades are seated in the disk slots by hammering them down into the broached slots, which may be configured as a fir tree shape. The blades are gradually driven into the broached slots in a circular manner by making multiple trips around a table/wheel that holds the disk in place while the blades are being installed. This method of manual blade installation is relatively time consuming and can cause impact damage to the blade root and/or broached disk slot. Root seal strip materials may require additional effort and force. 
     Accordingly, there is a need for a device to install unshrouded, shrouded or high aspect ratio blades into a disk that can improve the current assembly process. For example, a novel installation device that installs blades in a more controlled manner that prevents jamming and damaging of the blade roots or broached slots is needed. An improved installation method is also needed that is faster and does not require the repetitive manual hammering against the blade roots. 
     SUMMARY OF THE INVENTION 
     The present disclosure provides a blade installation device that includes a horizontal rotating arm and a fixed vertical pivot bar that is perpendicularly attached to a first end of the horizontal rotating arm via a sliding coupling mechanism. A vibratory impact device is attached to a second end of the horizontal arm that generates a vibrating motion via a power source. An impact shoe is attached to the vibratory impact device, which drives a turbine blade into a disk slot while simultaneously interlocking the outer shrouds at a z-notch. 
     The above-described and other features and advantages of the present disclosure will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a partial perspective view of a typical disk with shrouded blades installed according to the present disclosure; 
         FIG. 2  illustrates a perspective view of an embodiment of a blade installation device; and 
         FIG. 3  illustrates a partial side view of a vibratory impact device of the installation device and the rotational motion of the disk of the installation device according to the present disclosure, with the shroud portion of the blades removed for clarity. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings and in particular to  FIG. 1 , a disk, such as typically used in a turbine section of a gas turbine engine and generally referred to by reference number  10  is shown. The disk  10  has a plurality of shrouded blades  12  installed thereabout. The disk  10  has an outer rim  24  that receives a root portion  22  of blade  12 . The outer rim  24  of disk  10  has a plurality of fir tree shaped slots  14 , otherwise known as broached slots that receive the blade root  22  of blade  12 . Each blade  12  has an interlocking shroud  26  on the distal end  18  of blade  12 . The interlocking shrouds  26  of adjacent blades  12  mate at a matching z-notch  20 . The z-notch shrouds  20  aid in restricting leakage around the distal ends  18  of the blades  12  as well as provide blade vibratory damping. 
     The blade installation method of the present disclosure begins by loosely engaging blade root  22  of blade  12  with fir tree slot  14  so that blade root  22  has slack in the slot  14 . Blade  12  is not fully engaged with fir tree  14  so that the outer shroud  26  can be simultaneously twisted into position and interlocked at the z-notch  20 . Outer shroud  26  is designed to be twisted and loaded when being seated into place as blade  12  is fully engaged with disk  10 . 
     Referring now to  FIG. 2 , a blade installation device according to an embodiment of the present disclosure is shown, generally referred to by reference number  28 . A disk  10  is not shown installed for clarity. Installation device  28  has a fixed vertical pivot bar  30  that is mounted onto the fixed base of a rotary table  50 . A horizontal arm  34  is connected to vertical pivot bar  30  via a sliding coupling mechanism  32  that is adjustable in height by loosening locking knob  72 . Sliding coupling mechanism  32  allows for vertical height adjustment  46  and radial movement  70 , in relation to a disk  10 , to accommodate various diameter disks. Sliding coupling mechanism  32  is adjustable for angle  48  that allows installation device  28  to rotate about a longitudinal axis of vertical pivot bar  30  which allows it to move out of the way as the disk  10  is lowered from above onto rotary table  50 , as well as provide proper contact of shoe  56  with blade root  22 . 
     Rotary table  50  is rotationally driven by a stepping motor  60 , or other drive device, that can be set to rotate table  50  at variable speeds or discrete positions, in a stepwise fashion, in either direction. Rotary table  50  may have a non-slip surface, a protective surface, a vibration absorbing surface, guide pins and/or drive pins to properly locate and secure the disk to the table and prevent slipping of or damage to the disk. An interchangeable, spring loaded centering cone  52  is located in the center of rotary table  50  and functions to load the disk onto a self-centering mandrel  62 . Each interchangeable cone is sized to fit a particular disk. Spring loaded centering cone  52  is used when installation device  28  is positioned in a way such that horizontal arm  34  reaches from the outside of the disk toward the inside of the disk to make it easier to load the disk onto rotary table  50 . The device may also include a lockdown coupling (not shown) that clamps the disk against the table through threads on mandrel  62  or clamps on rotary table  50 . 
     A vibratory impact device  54  is attached to the distal end of horizontal arm  34  via a pivot coupling. Impact device  54  has variable load and/or variable frequency adjustments. Impact device  54  has an impact shoe  56  that drives the blades into the slots  14  automatically without damaging the blades  12  or the disk  10 . Electric, hydraulic, pneumatic, or any other type of power can drive the impacting device  54 . The impact provided by impact device  54  is created by either a spring loaded preload, a dead weight, an actuated piston, an electromechanical actuator, an impact loading and gravity, or any combinations thereof. Impact device  54  is capable of radial adjustment  40  and angular adjustment  42  via a pivot coupling, which allows the angle of incidence of impact shoe  56  to be adjusted. 
     Impact shoe  56  may be stiff or flexible as along as it has an adjustable shoe angle  58  so that it is capable of rotation about an axis of impact. Impact shoe  56  is composed of a hard, smooth and non-marring material such as raw hide, plastic, soft metals, coated metals, urethane rubber, or various combinations thereof. 
     The horizontal arm  34  of installation device  28  may be automated or may be operated manually. Horizontal arm  34  may have an adjustable sliding weight  36  thereon that functions to counterbalance the action of impact shoe  56 . 
     The blade installation method of the present disclosure simulates manual installation using a blade installation device  28 . Installation device  28  drives blades  12  into slots  14  using light single-blade or multi-blade impact combined with either manual or automated rotation of the turbine disk  10  on the rotary table  50 . An angle of incidence of impact shoe  56  relative to the blade root  22  and slot  14  imparts a twist on the blade when it is driven into the disk, which enables the outer shrouds to interlock. The vertical pivot bar  30  can also be centered inside the disk so that the horizontal arm  34  extends from the inner diameter of the disk, also known as the bore, toward an outer rim (not shown). As shown, the horizontal arm  34  may extend from an outer edge of rotary table  50  toward the center of the disk. 
     Variables such as table rotation speed, vibratory load, frequency, stepped position, rotation direction, angle of incidence and shoe pivot are developed on a case by case basis and are stored for later recall. A controller may also be used to synchronize the impact of impact shoe  56  with the rotation or positioning of rotary table  50  to completely automate the installation process. The rotation of the rotary table  50  may be in discrete steps via a stepper motor or continuous. 
     Referring now to  FIG. 3 , the interaction of vibratory impact device  54  with the blade roots according to the present disclosure is shown.  FIG. 3  illustrates impact shoe  56  of impact device  54  applying a force at an incidence angle theta (θ) while the turbine disk  10  rotates in direction  68 . The opposing force allows impact shoe  56  to adjust to its preferred angle of incidence so that the blade roots  22  are properly seated in fir tree slots  14 . The vibratory impact of the shoe  56  against the roots  22  along with the rotation of the disk  10  causes the outer shrouds  26  to interlock and load at the z-notches  20 . Impact shoe  56  may impact with a single blade individually or alternatively, impact shoe  56  may operate in a continuous motion such that it impacts multiple blades simultaneously. 
     While the present disclosure has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. For example, the methods and devices disclosed may be used to assemble bladed disks for compressor or turbine sections of aero, marine or land based turbines. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment(s) disclosed as the best mode contemplated, but that the disclosure will include all embodiments falling within the scope of the appended claims.