Abstract:
An apparatus for removing a root spring, the apparatus including a main body, a punch secured to the main body, and a driving mechanism coupled to the punch, wherein actuation of the driving mechanism moves the linear moving punch forward for engaging the root spring. The main body includes a front plate, a rear plate, a right side plate, a left side plate and an interior portion; wherein the right side plate and left side plate are substantially parallel with each other and each includes an elongated opening and a plurality of notches;

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims priority under 35 U.S.C. 119(e) to Provisional Application No. 62/111,392 filed Feb. 3, 2015, the contents of which are incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Field of Invention 
         [0003]    The present invention relates to a root spring removal tool and a method for using the tool to easily and conveniently remove a blade root spring from a blade root portion of a rotor assembly of a turbine. 
         [0004]    2. Description of Related Art 
         [0005]    As illustrated in  FIG. 1 , a blade  200  which is a turbine blade includes a blade part  201  and a blade root part  202  provided at one end of the blade part  201  on a rotor disk side. The rotor disk  203  includes a blade groove  204  which has a shape corresponding to the blade root part  202 . This blade groove  204  extends along an axial direction of a rotor. The blade  200  is supported by the rotor disk  203  by engaging the blade root part  202  to the blade groove  204 . A gap  205  is formed between the blade root part  202  and the blade groove  204 . In this gap  205 , a blade root spring  206 , as illustrated in  FIG. 2 , is inserted. The blade root spring  206  is configured to press the blade  200  outward in the radial direction of the blade groove  204  so that the blade root part  202  is brought into close contact with the blade groove  204  and the blade  200  is held there, as described in the U.S. patent application Ser. No. 13/847,554. 
         [0006]    As shown in  FIG. 2 , the root spring  206  is a leaf type spring with a narrow profile as viewed in the plane of displacement. This profile extends in the aforementioned plane for a distance approximately  20  the width profile. This geometry provides a large contact surface on both sides of the blade root spring  206 , which allows the blade root spring  206  to push the blade  200  outward in the radial direction with respect to the rotor disk  203 . However, this large contact surface creates a significant amount of friction when trying to remove the blade root spring  206 . 
         [0007]    Prior art techniques for removing a worn root spring include using a hammer to strike a narrow brass rod or similar material as a punch that is aligned by an operator with the root spring. However, it is difficult for the operator to align the punch so it is collinear with the axis of the root spring. Typically, the operator places the punch at an awkward angle to the root spring, which reduces the effectiveness of the punch, since the punch has the tendency to lose contact with the spring root when the punch is struck with the hammer. This causes the operator to spend additional time and effort to remove the root spring and increases the risk of the operator damaging the turbine disk or turbine blades during the removal process. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    In view of these circumstances, an aspect of the present invention is to provide a spring root removal tool that provides a collinear force to the root spring and mitigates the occurrence of the spring removal tool from losing contact with the root spring during removal. According to another aspect of the invention, the spring root removal tool is hand operated and designed to remove the root spring in a restricted space, i.e., between two adjacent rows of turbine blades. The spring root removal tool may be used in all types of turbine engines, including gas turbine engines, steam turbine engines, aircraft engines, and others. 
         [0009]    According to another aspect of the present invention for removing a root spring, the apparatus comprising: a main body; a punch secured to said main body; and a driving mechanism coupled to said punch, wherein actuation of said driving mechanism moves said linear moving punch forward for engaging the root spring. 
         [0010]    According to another aspect of the present invention, an apparatus, comprising: a main body including a front plate, a rear plate, a right side plate, a left side plate and an interior portion; wherein the right side plate and left side plate are substantially parallel with each other and each includes an elongated opening and a plurality of notches; a linkage mechanism attached to the main body and configured to slide along the elongated openings; a punch provided in the interior portion and configured to be attached to the linkage mechanism; a driving mechanism coupled to the linkage mechanism and configured to engage the plurality of notches, the driving mechanism drives the punch via the linkage mechanism by engaging at least one the plurality of notches in a ratchet like manner. According to another aspect of the present invention, the front plate, the rear plate, the right side plate and the left side plate are joined together at substantial right angles. According to another aspect of the present invention, the elongated openings extend across substantially the entire right and left side plates. According to another aspect of the present invention, the plurality of notches extend across substantially the entire right and left side plates. According to another aspect of the present invention, the elongated openings have substantially the same size and shape. According to another aspect of the present invention, the plurality of notches have substantially the same size and shape. According to another aspect of the present invention, the front plate included\s a through hole for receiving the punch. According to another aspect of the present invention, a handle configured to be attached to the driving mechanism. According to another aspect of the present invention, the front plate includes a recess portion. According to another aspect of the present invention, the rear plate includes a recess portion. According to another aspect of the present invention, the punch includes an opening, an end portion and a tip portion. According to another aspect of the present invention, the linkage mechanism includes a small through hole and a large through hole. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    Further characteristics and advantages of the present invention will be more readily apparent from the description of the preferred by non-exclusive embodiments of the root spring removal tool and method, illustrated by way of non-limiting examples in the accompanying drawings, in which: 
           [0012]      FIG. 1  shows a conventional a turbine blade that includes a blade part and a blade root part. 
           [0013]      FIG. 2  shows a conventional leaf type root spring with a narrow profile as viewed in the plane of displacement. 
           [0014]      FIGS. 3A and 3B  show a root spring removal tool according to an embodiment of the present invention. 
           [0015]      FIG. 4  shows a perspective view of right and left side plates according an embodiment of the present invention. 
           [0016]      FIGS. 5A and 5B  show a perspective view of a front plate according an embodiment of the present invention. 
           [0017]      FIGS. 6A and 6B  show a perspective view of a rear plate according an embodiment of the present invention. 
           [0018]      FIG. 7  shows a perspective view of a linear moving punch according an embodiment of the present invention. 
           [0019]      FIG. 8  shows a perspective view of a sliding bolt according an embodiment of the present invention. 
           [0020]      FIG. 9  shows a perspective view of a linkage mechanism according an embodiment of the present invention. 
           [0021]      FIG. 10  shows a perspective view of a driving mechanism according an embodiment of the present invention. 
           [0022]      FIG. 11  shows a perspective view of a securing bolt according an embodiment of the present invention. 
           [0023]      FIG. 12  shows a perspective view of a handle according an embodiment of the present invention. 
           [0024]      FIGS. 13-19  illustrate an example according to an aspect of the present invention of how an operator is able to remove a root spring using a root spring tool. 
       
    
    
       [0025]    The same reference numerals have used to identify similar elements in the Figures. 
       DESCRIPTION OF THE INVENTION 
       [0026]      FIGS. 3A and 3B  illustrates an embodiment of a root spring removal tool according to an aspect of the present invention. As shown in  FIGS. 3A and 3B , a root spring removal tool  1  includes a main body  2 , which is comprised of four plates, a right side plate  10 , a left side plate  30 , a front plate  50 , and a rear plate  70 . The front plate  50 , rear plate  70  and the right and left side plates  10  and  30  are attached (or welded) together at substantial right angles to form the main body  2 . 
         [0027]    As shown in  FIGS. 3B and 4 , the right side plate  10  has a top surface  11 , a rear surface  12 , a bottom surface  13 , a front surface  14 , an outer surface  15 , an inner surface  16 , an elongated opening  17  and a plurality of notches  18 . The elongated opening  17  is provided entirely within the lower half of the right side plate  10  and extends across substantially the entire right side plate  10  in an axial direction of the main body  2 . The plurality of notches  18  are provided in the upper half of the right side plate  10  in a ratchet like pattern. Each of the notches  18  may be of the same size and may be provided an equal distance a part from each other. As shown in  FIG. 3A and 4 , each of the notches  18  has a right side wall  19 , a left side wall  20  and a bottom portion  21 . The right and left side walls  18  and  19  extend in parallel to each other and are inclined towards the front plate  50  such that the side walls  18  and  19  form an acute angle with the top surface  11 . 
         [0028]    As illustrated in  FIG. 3B and 4 , the left side plate  30  has the same configuration as the right side plate  10  and is provided in parallel with the right side plate  10  in the main body  2 . That is, the left side plate  30  includes a top surface  31 , a rear surface  32 , a bottom surface  33 , a front surface  34 , an outer surface  35 , an inner surface  36 , an elongated opening  37  and a plurality of notches  38 . In addition, the elongated opening  37  of the left side plate  30  has substantially the same size and shape as the elongated opening  17  of the right side plate  10  and the elongated openings  17  and  37  are provided in parallel with each other in the main body  2 . Similarly, the notches  38  of the left side plate  30  each have substantially the same size and shape as the notches  18  of the right side plate  10  and are provided in parallel with each other in the main body  2 . 
         [0029]    As illustrated in  FIGS. 5A and 5B , the front plate  50  has a top surface  51 , a rear (inner) surface  52 , a bottom surface  53 , a front surface  54 , a right side surface  55  and a left side surface  56 . As also illustrated in  FIGS. 5A and 5B , the front plate  50  includes a front recessed portion  57 , which is formed along the bottom of the front plate  50 ; and the inner surface  52  includes right and left recessed portions  58  and  59 , which are formed along the right and left edges of the inner surface  52 , respectively. The front recessed portion  57  is configured such that the front plate  50  of the main body  2  can be positioned on the appropriate hardware of the rotor disk during removal of a root spring. The right and left recessed portions  58  and  59  are provided for welding the front plate  50  to the front surfaces  14 ,  34  of the right and left side plates  10  and  30 , respectively. 
         [0030]    In addition, as shown in  FIGS. 5A and 5B , the front plate  50  includes a through hole  60 , for example, having a rectangular shape that extends from the rear inner surface  52  to the front surface  54 . The through hole  60  is provided just above the front recessed portion  57  and at a substantially equal distance away from the right and left side surfaces  55  and  56 . As illustrated in  FIGS. 3B and 5A , the front surface  54  is offset at an acute angle from the inner surface  52 , such that the left side surface  56  has a longer length than the right side surface  55 , in order for the front surface  54  to have the same angle as the blade grooves in the rotor disc, as discussed more fully below. 
         [0031]    As illustrated in  FIGS. 6A and 6B , the rear plate  70  includes a top surface  71 , a rear surface  72 , a bottom surface  73 , a front (inner) surface  74 , a right side surface  75  and a left side surface  76 . As also illustrated in  FIGS. 6A and 6B , the rear plate  70  includes a rear recess portion  77  and an incline surface  80 , which are both formed on the rear surface  72 . The rear recess portion  77  is formed on the top half of the rear surface  72  and the incline surface  80  is formed at the corner of the rear surface  72  and the bottom surface  73 . Both the rear recess portion  77  and the incline surface  80  are configured such that the rear plate  70  of the main body  2  can be positioned on the appropriate hardware of the rotor disk during removal of a root spring. 
         [0032]    Further, as illustrated in  FIG. 6A and 6B , the inner surface  74  includes right and left recessed portions  78  and  79 , which are formed along the right and left edges of the inner surface  74 , respectively. The right and left recessed portions  78  and  79  are provided for welding the rear plate  70  to the rear surfaces  12 ,  32  of the right and left side plates  10  and  30 , respectively. 
         [0033]    As illustrated in  FIGS. 3B and 6B , the rear surface  72  is offset at an acute angle from the inner surface  74 , such that the right side surface  75  has a longer length than the left side surface  76 . That is, as shown in  FIG. 3B , the rear surface  72  is substantially in parallel with the front surface  54  of the front plate  50  in the main body  2  in order for the offset front surface  54  and rear surface  72  to have the same angle as the blade grooves in the rotor disc, as discussed more fully below. In addition, as shown in  FIG. 3B , the inner surface  52  of the front plate  50  and the inner surface  74  of the rear plate  70  are substantially in parallel with each other in the main body  2 . 
         [0034]    As discussed above, the front plate  50 , the rear plate  70  and the right and left side plates  10  and  30  are welded together at substantial right angles to form the main body  2 . More specifically, the right and left recessed portions  78  and  79  of the rear plate  70  are welded to the rear surfaces  12 ,  32  of the right and left side plates  10  and  30 , respectively; such that the top surface  71 , the bottom surface  73  and the right and left side surfaces  75  and  76  of the rear plate  70  are substantially flush with the top surfaces  11 ,  31 , the bottom surfaces  13 ,  33  and the outer surfaces  15 ,  35 , of the left and right side plate  10  and  20 , respectively. And, the right and left recessed portions  58  and  59  of the front plate  50  are welded to the front surfaces  14 ,  34  of the right and left side plates  10  and  30 , respectively; such that the top surface  51 , the bottom surface  53  and the right and left side surfaces  55  and  56  of the front plate  50  are substantially flush with top surfaces  11 ,  31 , the bottom surfaces  13 ,  33  and the outer surfaces  15 ,  35 , of the right and left side plates  10  and  30  respectively. 
         [0035]    As illustrated in  FIG. 3B , the main body  2  has an interior portion  85 , which is formed by welding the front and rear plates  50  and  70  to the right and left side plates  10  and  30 . A linear moving punch  80  is provided to move within the interior portion  85 . As shown in  FIG. 7 , the linear moving punch  80  has a ram portion  81  and an end portion  82 . The ram portion  81  has a tip portion  84  and the end portion  82  has an opening  83 , which is provided on two opposite sides of the end portion  82  and passes completely through the center of the end portion  82 . The opening  83  is configured to receive a sliding bolt  140 , which is used to secure the linear moving punch  80  to the main body  2  via the elongated openings  17  and  37 . 
         [0036]    As illustrated in  FIG. 8 , the sliding bolt  140  includes a bolt head portion  141 , a main portion  142  and a groove portion  143 , which is able to receive a retainer spring (not shown). The bolt head  141  has a larger diameter than the main portion  142  and is provided at an opposite end from the groove portion  143 . The main portion  142  has a cylindrical shape with a diameter slightly less than the width of the elongated holes  17 ,  37 , which allows the main portion  142  to move freely along the elongated holes  17 ,  37 . 
         [0037]    Right and left linking mechanisms  90 R,  90 L are provided, as shown in  FIGS. 3B and 9 , in order secure the linear moving punch  80  to the elongated holes  17  and  37  of the main body  2 . As illustrated in  FIG. 9 , the right linking mechanism  90 R has an oval type shape and includes a small (diameter) through hole  91  and a large (diameter) through hole  92 . The left linking mechanism  90 L has the same configuration as the right linking mechanism  90 R. 
         [0038]    In order to secure the moving punch  80  to the main body  2 , the large through holes  92  of the linking mechanisms  90 R,  90 L are aligned with the elongated holes  17 ,  37 , respectively, and the sliding bolt  140  is provided through the left linking mechanism  90 L, the elongated hole  37 , the opening  83  of the moving punch  80 , the elongated hole  17  and the right linking mechanism  90 R and is then secured by placing a retainer spring ring (not shown) in the groove portion  143 . 
         [0039]    Once the moving punch  80  is secured to the main body  2 , the ram portion  81 , which extends from the center of the end portion  82  in the axial direction and has the same shape as the through hole  60 , is able to pass through the through hole  60  of the front plate  50  and remove a root spring as the linear moving punch  80  is advanced forward along the elongated openings  17  and  37 , as discussed more fully below. 
         [0040]    The linking mechanisms  90 R,  90 L are also configured to be secured to driving mechanism  100 R,  100 L, respectively, by using securing bolt  110 , as shown in  FIG. 3A . As illustrated in  FIG. 10 , the right driving mechanism  100 R has an elongated oval shape and includes first, second, third and fourth through holes  101 - 104  all of which have substantially the same diameter as each other as well as that of the small through holes  91  of the linking mechanisms  90 R,  90 L. The left driving mechanism  100 L has the same configuration as the right driving mechanism  100 R. 
         [0041]    As shown in  FIG. 11 , the securing bolt  110  has a bolt head portion  111 , a cylinder portion  112  and a flange portion  113 . The head portion  111  has a diameter larger than the cylinder portion  112  and the cylinder portion  112  has a diameter just slightly smaller than the fourth through hole  104  of the driving mechanisms  100 R,  100 L and the small through hole  91  of the linking mechanisms  90 R,  90 L. As shown in  FIG. 3A , the securing bolt  110  is inserted through the small through hole  91  of the linking mechanism  90 R and into the fourth through hole  104  of the driving mechanism  100 R, such that the linking mechanism  90 R is attached to the driving mechanism  100 R. The same procedure is provided for attaching the linking mechanism  90 L to the driving mechanism  100 L. 
         [0042]    As shown in  FIG. 3A , the driving mechanisms  100 R,  100 L extend in a radial direction and are attached to each other via their respective first, second and third and through holes  101 - 103 . As shown in the  FIG. 3A , a lever handle  120  is secured between the driving mechanisms  100 R,  100 L at the first and second through holes  121  and  122 . That is, as shown in  FIG. 12 , the handle  120  has a rectangular cuboid shape and includes first and second holes  121 ,  122  provided on two opposite sides of the handle  120 . The first and second holes  121  and  122  are provided the same distance apart as the first and second through holes  101  and  102  such that the first and second holes  121  and  122  can be aligned with the first and second through holes  101  and  102  and the driving mechanisms  100 R,  100 L can be attached to each other with the handle  120  in between via two screws. In addition, washers  130 , as shown in  FIG. 3A , are provided between the handle  120  and each of the driving mechanism  100 R,  100 L in order to for the handle  120  to be securely position between the driving mechanisms  100 R,  100 L. Also, the first and second through holes  101  and  102  of the right driving mechanism  100 R each have internal threads for receiving the screws used to attach the handle  120  to the driving mechanisms  100 R,  100 L. 
         [0043]    In addition, as shown in  FIG. 3A , a ratchet screw  150  is provided between the third through holes  103  of the driving mechanism  100 R,  100 L. The ratchet screw  150  is configured to screw into the internal threads of the right driving mechanism  100 R and is provided at a height such it is able to engage with the plurality of notches  18  and  38  of the main body  2  in a ratchet like manner, as discussed more fully below. 
         [0044]      FIGS. 13-19  illustrate an example according to an aspect of the invention of how an operator is able to remove a root spring using the root spring tool  1 . First, as shown in  FIG. 17 , the main body  2  is provided between two adjacent rows of turbine blades. For example, if the fourth row of turbine blade has a root spring, then the main body will be positioned between the third  160  and fourth  170  rows. Specially, the incline surface  80  and the rear recess portion  77  of the rear plate  70  are configured such that the rear plate  70  can be positioned on the radius surface of the turbine disc of the third row  160  without interfering with the disc&#39;s radius circumferential surface and its downstream locking screws, respectively. And, the front plate  50  of the main body  2  can be positioned on the appropriate hardware of the rotor disk of the fourth row  170  based on the configuration of the front recessed portion  57 , as shown in  FIG. 17 . 
         [0045]    Next, after the main body  2  is properly installed between the third  160  and fourth  170  rows of turbine blades, the tip portion  84  of the moving punch  80  is then align with the root spring that is to be removed. That is, the main body  2  is configured such that once it is install between the rows, the moving punch  80  is provided at substantially the same height as the root spring that is to be removed. Further, since the front surface  54  and the rear surface  72  are offset to have the same angle as the blade groove in the rotor disc, as discussed above, the moving punch  80  is provided to be collinear with the axis of the root spring. 
         [0046]    In an initial position, as shown in  FIG. 13 , the end portion  82  of the moving punch  80  is provided near the rear plate  30  and the tip portion  84  does not extend beyond the front surface  54  of the front plate  50 . In this initial position, an operator places the ratchet screw  150  in a pair of parallel notches  18  and  38  located slightly downstream of the linkage mechanisms  90 R,  90 L and positions the driving mechanisms  100 R,  110 L and the lever handle  120  slightly forward at an angle this is equal to or less than the right and left side walls  19  and  20  the notches  18 . 
         [0047]    Next, the operator pulls the lever handle  120  towards the rear plate  70  into an intermediate position, as shown in  FIG. 14 , such that the driving mechanisms  100 R,  110 L and handle  120  rotate about the axes of the notches  18  and  38 , which drives the linear moving punch  80  forward along the elongated grooves  17 ,  37 , and finally into a pulled position, as shown in  FIGS. 15 and 18 . This movement causes the end portion  82  to advance downstream in the grooves  17 ,  37 , as shown in  FIGS. 14 and 15 , which allows the tip portion  84  of the punch  80  to advance through the passage  60  and to extend beyond the front surface  54  of front plate  50 , as shown in  FIG. 15 . 
         [0048]    After the operator finishes with the pull action, the operator then advances the ratchet screw  150  into the next downstream pair of notches  18 ,  38  and begins again at the initial position as shown in  FIG. 16 . As this sequence is repeated for each of the subsequent pairs of downstream notches  18 ,  38 , the moving punch  80  advances into the blade root portion as shown in  FIG. 19  and the blade root is pushed out of the blade root accordingly. That is, the multiple axes of the notches  18 ,  38  are laid out in a ratchet-like manner and the spacing of these multiple axes are designed to allow successive actuations of the handle  120  in the restricted operating area between two rows of turbine blades. 
         [0049]    From the above description of preferred embodiments of the invention, those skilled in the art will perceive improvements, changes and modifications. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims. Further, it should be apparent that the foregoing relates only to the described embodiments of the present application and that numerous changes and modifications may be made herein without departing from the spirit and scope of the application as defined by the following claims and the equivalents thereof. 
       REFERENCE LIST 
       [0050]    Root spring removal tool  1 , Main body  2 . 
         [0051]    Right side plate  10 , top surface  11 , rear surface  12 , bottom surface  13 , front surface  14 , outer surface  15 , inner surface  16 , elongated opening  17 , notches  18 , right and left side walls  19  and  20 , bottom portion  21 . 
         [0052]    Left side plate  30 , top surface  31 , rear surface  32 , bottom surface  33 , front surface  34 , outer surface  35 , inner surface  36 , elongated opening  37 , notches  38 . 
         [0053]    Front plate  50 , top surface  51 , rear surface  52 , bottom surface  53 , front surface  54 , right side surface  55 , left side surface  56 , front recessed portion  57 , right recessed portion  58 , left recessed portion  59 , front through hole  60 . 
         [0054]    Rear plate  70 , top surface  71 , rear surface  72 , bottom surface  73 , front (inner) surface  74 , right side surface  75 , left side surface  76 , rear recess portion  77  and incline surface  80 , right and left recessed  78 ,  79 , interior portion  85 . 
         [0055]    Linear moving punch  80 , ram portion  81 , end portion  82 , opening  83 , tip portion  84  ( FIG. 7 ). 
         [0056]    Sliding bolt  140 , bold head portion  141 , main portion  142 , and groove portion  143  ( FIG. 8 ). 
         [0057]    Linkage mechanism  90 R,  90 L, small through hole  91 , large through hole  92  ( FIG. 9 ). 
         [0058]    Driving mechanism  100 R,  100 L, first through hole  101 , second through hole  102 , third through hole  103  and fourth through hole  104  ( FIG. 10 ). 
         [0059]    Securing bolt  110 , bold head portion  111 , cylinder portion  112  and flange portion  113  ( FIG. 11 ). 
         [0060]    Lever handle  120 , first and second through hole  121 ,  122  ( FIG. 12 ) 
         [0061]    Washer  130 , Ratchet screw  150 , Third row of turbine blades  160 , Fourth row of turbine blades  170