Abstract:
A self indexing portable automated tenon peening device including: a peening machine in operable communication with a mounting arm; a circumferential slide assembly including a circumferential rail in operable communication with the mounting arm; an axial slide assembly including a axial slide rail in operable communication with the circumferential slide assembly; a base in operable communication with the axial slide assembly; and a programmable logic controller for controlling a position of the circumferential slide assembly and the axial slide assembly.

Description:
BACKGROUND 
   The present disclosure relates to a portable automated peening apparatus for automatically peening steam turbine bucket tenons and a method for automated peening steam turbine bucket tenons. 
   In the construction of turbines, for example, steam turbines, cover plates are employed for a variety of reasons and are generally secured to the tips of the turbine buckets by peening tenons formed on the buckets or the cover plates. As used herein the term peen refers to the end of a hammerhead such as a spherical or flat striking surface, often wedge-shaped or ball-shaped and used for chipping, indenting. Radial peening is oftentimes used in certain bucket constructions. Not only is the riveting operation loud but there is substantial variation from tenon to tenon based on operator action. It should be appreciated that the terms peening and riveting are interchangeably used herein. While certain automated peening tools, including reciprocating, orbital and radial tools are available; no currently available portable automated peening apparatus automatically peens a tenon as well as a tenon peened by a manual operation. Accordingly, it is desirable to provide a portable automated machine and methods for peening tenons for securing cover plates and adjacent bucket tips of a turbine wheel to one another. 
   BRIEF DESCRIPTION 
   Disclosed herein is a portable automated tenon peening device including: a peening machine in operable communication with a mounting arm; a circumferential slide assembly including a circumferential rail in operable communication with the mounting arm; an axial slide assembly including a axial slide rail in operable communication with the circumferential slide assembly; a base in operable communication with the axial slide assembly; and a programmable logic controller for controlling a position of the circumferential slide assembly and the axial slide assembly. 
   Also disclosed herein is a tenon peening method including: positioning a portable automated peening device relative to a turbine wheel; securing the portable automated penning device; measuring a distance from a peening machine to a tenon; positioning a peening machine to peen the tenon with a circumferential slide assembly and an axial slide assembly; and peening said tenon with said peening machine. 
   Other systems, methods, and/or computer program products according to exemplary embodiments will be or become apparent to one with skill in the art upon review of the following drawings and detailed description. It is intended that all such additional systems, methods, and/or computer program products be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying figures, wherein: 
       FIG. 1  is a fragmentary axial view illustrating a plurality of buckets with an attached cover; 
       FIG. 2  is a fragmentary enlarged view illustrating the tenons and openings through the cover prior to assembly; 
       FIG. 3  is a fragmentary cross-sectional view illustrating a flush tenon cover/bucket connection; 
       FIG. 4  is a schematic view of an exemplary embodiment of a portable automated peening device; 
       FIG. 5  is a schematic view of an exemplary embodiment of a circumferential slide assembly; 
       FIG. 6  is a schematic view of an exemplary embodiment of a axial slide assembly; and 
       FIG. 7  is an alternate schematic view of the portable automated peening device shown in  FIG. 4 . 
   

   DETAILED DESCRIPTION 
   Referring now to  FIG. 1 , there is illustrated a plurality of buckets  10  forming part of a rotating component of a turbine, generally indicated  12 , of a steam turbine. Covers  14  are secured to outer tips of the buckets, the covers extending in a circumferential direction. As illustrated in  FIGS. 2 and 3 , the tips of the buckets  10  have one or more tenons  16  projecting radially outwardly of the tips. Each cover  14  is typically provided in an arcuate circumferentially extending segment for spanning a plurality of buckets, for example, four or five buckets, and has openings  18  for receiving the tenons. The tenons are received in the openings  18  and peened to form a flush cover design, as illustrated in  FIG. 3 . 
   Turning now to  FIG. 4 , an exemplary embodiment of a portable automated peening device is depicted generally as  32 . The portable automated peening device  32  includes a peening machine  34 , which is in operable communication with a mounting arm  36 . The mounting arm  36  includes a radial slide assembly  66 , the radial slide assembly includes, but is not limited to a, a wheel, a gear, any other suitable device. The mounting arm is slidably disposed upon a circumferential slide assembly  40 . The peening machine  34  may be slidably mounted to the mounting arm  36  such that the position of the peening machine  34  may be adjusted with respect to the mounting arm  36 . The circumferential slide assembly  40  is slidably disposed upon an axial slide assembly  44 . The circumferential slide assembly  40  and the axial slide assembly  44  are used to properly position the peening machine  34  to peen the tenons  16  ( FIG. 2 ) to the bucket tips. The movements of the peening machine  34 , the circumferential slide assembly  40 , and the axial slide assembly  44  are controlled by a programmable logic controller (not shown). 
   Continuing now with reference to  FIG. 5 , an exemplary embodiment of the circumferential slide assembly is depicted generally as  40 . The circumferential slide assembly includes a circumferential rail  38 , which is mounted to a circumferential slide body  42 . The circumferential slide body  42  may be constructed of any material suitable to support the weight of the mounting arm  36  and the peening machine  34  and also the force exerted by the peening machine  34 . Additionally, one side of the circumferential slide body  42  has a generally curved shape with an arc similar to that of the circumferential slide rail  38 . 
   The mounting arm  36  may be moved along the circumferential rail  38  by a first actuator  54 . The first actuator  54  may be, but is not limited to, a hydraulic actuator, an electric actuator, or a pneumatic actuator. A programmable logic controller (not shown) may control the first actuator  54 . The circumferential slide assembly  40  also includes an operator-swinging pendant  58 , which includes the control interface for the operator to use the portable automated peening device  32 . The circumferential slide assembly  40  further includes a second slide device  60  disposed on the circumferential slide body  42 , the second slide device includes, but is not limited to a, a wheel, a gear, any other suitable device. 
   Referring now to  FIG. 6 , an exemplary embodiment of the axial slide assembly is depicted generally as  44 . The axial slide assembly  44  includes an axial rail  46 , a vertical support  50 , a clamp  52 , and an axial slide body  68 . The circumferential slide assembly  40  ( FIG. 4 ) is moved along the axial rails  46  by a second actuator  56 . In another exemplary embodiment, the axial slide assembly  44  may include a plurality of axial rails  46 . The second actuator  56  may be, but is not limited to, a hydraulic actuator, an electric actuator, or a pneumatic actuator. The programmable logic controller may control the movement of the second actuator  56 . In alternative exemplary embodiments, a user may move the circumferential slide assembly  40  along the axial rails  46  manually. 
   Continuing with reference to  FIG. 6 , the vertical support  50  is disposed on the opposite side of the axial slide body  68  from the axial rail  46  and the vertical support is designed to allow a user to move the portable automated peening device  32  without the use of additional equipment, such as an overhead crane system. In an exemplary embodiment the vertical support  50  may be an air caster. Additionally, the clamp  52 , which is disposed on the axial slide body  68 , allows the portable automated peening device  32  to be securely positioned before the peening machine  34  ( FIG. 4 ) is activated. The axial slide assembly  44  further includes a support member  62 , which is designed to support the turbine rotor  10  during peening. The support member  62  may be of a fixed height or in an alternative exemplary embodiment the height of the support member  62  may be adjustable. Additionally, the support member  62  may be slidably disposed upon the axial slide body  68  such that the position of the support member  62  may be adjusted. 
   Returning now to  FIG. 4 , in an exemplary embodiment the automated peening device  32  includes a distance finder  64  that is capable of accurately measuring the distance to the tenon to be peened. The distance finder  64  may be affixed to the peening machine  34  or to the mounting arm  36 . In an exemplary embodiment, the distance finder  64  is a laser distance finder. The laser distance finder  64  communicates the measured distance to the programmable logic controller, which responsively controls the position of the peening machine  34  by controlling the first actuator  54  and the second actuator  56 . It is contemplated that the circumferential slide assembly  40  can be designed to provide for a wide range of circumferential movement. Likewise, the axial slide assembly  44  can be designed to provide for a wide range of axial movement depending upon the size of the axial slide body  68 . In exemplary embodiments, the mounting arm  36  may include a radial positioning table that allows for angular adjustment of the peening machine  34  relative to the orientation of the tenons. The radial positioning table facilitates the peening of angled tenons. 
   Turning now to  FIG. 7 , an alternate schematic view of the portable automated peening device  32  is depicted. As illustrated, the circumferential slide assembly  40  is slidably disposed upon the axial rail  46 , which is affixed to the axial slide body  68 . The axial slide assembly  44  includes the vertical support  50  disposed on the opposite side of the axial slide body  68  from the axial rail  46 . The vertical support  50  is used to properly position the automated peening device  32  for peening of the turbine  12 . After the automated peening device  32  is properly positioned it is secured using the clamp  52  ( FIG. 6 ). The clamp  52  is disposed on the axial slide body  68 . The axial slide assembly  44  and the circumferential slide assembly  40  are used to properly position the peening machine  34  for peening. In exemplary embodiments, the peening machine  34  is affixed to a second axial slide assembly  70 , which is also affixed to the mounting arm  36 . The second axial slide assembly  70  allows for adjustment of the peening machine in the axial direction with respect to the turbine  12 . 
   In another exemplary embodiment, the programmable logic controller, which controls the movements of the first actuator  54  and the second actuator  56  and thereby the position of the peening machine  34 , includes a safety function. The safety function is designed to ensure that the portable automated peening device  32  is secured before the peening machine  34  is used. The programmable logic control may sense the state to the clamp  52  to determine if the portable automated peening device  32  is properly secured. 
   In exemplary embodiments the portable automated peening device  32  is operable to sweep multiple locations, in other words the portable automated peening device  32  can slide along the linear axis of the turbine  12 , and peen several rows of tenons  16  without moving the portable automated peening device  32 . Additionally, the portable automated peening device  32  can peen several tenons  16  radially while the portable automated peening device  32  remains stationary. It is also contemplated that the portable automated peening device  32  may be indexed around the turbine  12 , in the case that the turbine  12  is mounted on a lathe. However, the portable automated peening device  32  is designed to be portable and is intended to be shipped to various locations. 
   While the invention has been described with reference to an exemplary embodiment, 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 invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.