Abstract:
A tool for assembling and disassembling a plasma spray gun comprises a first removal and installation head, including a body, a drive socket and first and second prongs, which are spaced to mate with corresponding sockets disposed in a first plasma spray gun component, such as a cathode holder. In addition, the tool may comprise a second removal and installation head, including a body and first and second prongs, which are spaced to mate with corresponding sockets disposed in a second plasma spray gun component, such as a locking ring. The second removal and installation head is configured to attach to the first removal and installation head. The tool is ergonomically designed and easily allows the removal and/or installation of plasma spray gun components.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a tool for assembling and disassembling a plasma spray gun. More specifically, the present invention relates to an ergonomic tool, which easily and comfortably removes and/or installs plasma spray gun components. 
         [0002]    Gas turbine engine components are exposed to extreme temperatures and pressures during the course of operation. Therefore, coatings are typically applied to gas turbine engine components in order to protect the underlying component from degradation and wear. Conventional spray technology for applying the coatings typically utilizes standard plasma spray guns, such as the Sulzer-Metco 3 MB or a similar design. The materials which comprise the coating composition are rapidly heated in the plasma flame and accelerated at a high velocity onto the engine component, such that the heated composition adheres to the component&#39;s surface and forms the coating. 
         [0003]    Conventional plasma spray guns are basically formed of an electrically conductive rear gun component, a front gun component and an electrical insulator sandwiched between the front and rear gun components. Due to the design of conventional plasma spray gun mounting hardware, removal and installation of plasma gun components is difficult. In an effort to access the closely spaced components, current plasma gun wrench designs do not offer superior mechanical advantage. Also, the removal problem is further exacerbated when the plasma gun components are overtightened during assembly. Since the configuration of the plasma spray gun prevents current wrench designs from providing enough torque to remove overtightened components, a hammer must sometimes be used to apply additional force to the handle of the wrench to achieve removal. Use of a hammer is undesirable because the force applied can damage both the wrench and the plasma spray gun components themselves. 
         [0004]    Therefore, there is a need in the art for an ergonomically designed plasma spray gun tool, which allows for plasma spray gun components to be easily and efficiently removed. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    The present invention is tool for assembling and disassembling a plasma spray gun. The tool comprises a first removal and installation head, including a body, a drive socket and first and second prongs, which are spaced to mate with corresponding sockets disposed in a first plasma spray gun component, such as a cathode holder. In addition, the tool may comprise a second removal and installation head, including a body and first and second prongs, which are spaced to mate with corresponding sockets disposed in a second plasma spray gun component, such as a locking ring. The second removal and installation head is configured to attach to the first removal and installation head. The tool is ergonomically designed and easily allows the removal and/or installation of plasma spray gun components. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective side view of a first removal and installation head configured for use with a rear component of a plasma spray gun. 
           [0007]      FIG. 2  is a perspective front view of a second removal and installation head configured for use with a front component of a plasma spray gun. 
           [0008]      FIG. 3  is a perspective view of the second removal and installation head positioned for attachment to the first removal and installation head. 
           [0009]      FIG. 4  illustrates the first removal and installation head coupled to a wrench and positioned to mate with a cathode holder. 
           [0010]      FIG. 5  illustrates the second removal and installation head attached to the first removal and installation head and positioned to mate with a locking ring. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]      FIG. 1  is a perspective side view of first removal and installation head  10 , which is configured for use with a rear component of a plasma spray gun. First removal and installation head  10  includes body  12 , first and second prongs  14 A and  14 B, and drive socket  16 . First and second prongs  14 A- 14 B extend outward from a distal surface of body  12 . Drive socket  16  is attached to a proximal surface of body  12  and includes recess  18 . 
         [0012]    As shown in  FIG. 1 , first removal and installation head  10  is specifically configured for compatibility with a cathode holder located on the rear component of a conventional plasma spray gun, such as the Sulzer-Metco 3 MB or a similar design. (Use of first removal and installation head  10  in conjunction with a cathode holder is described in detail with respect to  FIG. 4 .) However, the invention is not so limited and first removal and installation head  10  may be configured for use with another plasma spray gun component. 
         [0013]    In an exemplary embodiment, body  12  of first removal and installation head  10  is generally circular and has a diameter of about 1.250 inches (3.175 centimeters). Drive socket  16  is integrally formed with or welded onto the center of the proximal surface of body  12 . Drive socket  16  is a standard ⅜ inch drive socket and includes square recess  18  at one end, which allows drive socket  16  to couple with a wrench (as described in detail with respect to  FIG. 4 ). In an exemplary embodiment, prongs  14 A and  14 B are about 0.3 inches (0.762 centimeters) in length and about 0.190 inches (0.483 centimeters) in diameter. Prongs  14 A and  14 B extend from the distal surface of body  12  and are positioned along a center line extending across the diameter of body  12 . Prongs  14 A and  14 B are spaced about 0.650 inches (1.65 centimeters) apart. However, it should be understood that the dimensions of first removal and installation head  10  may vary depending on the configuration of the corresponding plasma spray gun component. For instance, in an exemplary embodiment, the length of prongs  14 A and  14 B could range from about 0.1 inches (0.254 centimeters) to about 0.5 inches (1.27 centimeters) and the distance between prongs  14 A and  14 B could range from about 0.25 inches (0.635 centimeters) to about 1 inch (2.54 centimeters). 
         [0014]    First removal and installation head  10  may be comprised of a metal, such as carbon steel or any other suitable material. In addition, first removal and installation head  10  may be formed of individual parts, which are welded together or first removal and installation head  10  may also be formed, for example, of a single unitary piece of molded or forged metal. 
         [0015]      FIG. 2  is a perspective side view of second removal and installation head  20 , which is configured for use with a front component of a plasma spray gun. Second removal and installation head  20  includes body  22 , first and second prongs  24 A and  24 B, attachment holes  26 A and  26 B and magnetic layer  28 . First and second prongs  24 A- 24 B extend outward from a distal surface of body  22 . Attachment holes  26 A and  26 B extend through body  22 . Magnetic layer is attached to a proximal surface of body  22 . 
         [0016]    As shown in  FIG. 2 , second removal and installation head  20  is specifically configured for compatibility with a linking ring located on the front component of conventional plasma spray gun, such as the Sulzer-Metco 3 MB or a similar design. (Use of second removal and installation head  20  in conjunction with a linking ring is described in detail with respect to  FIG. 5 .) However, the invention is not so limited and second removal and installation head  20  may be configured for use with another plasma spray gun component. 
         [0017]    In an exemplary embodiment, body  22  of second removal and installation head  20  is generally rectangular and has a length of about 1.90 inches (4.826 centimeters) and a width of about 1.250 inches (3.175 centimeters). Attachment holes  26 A and  26 B are positioned though a center line extending across the width of body  22  and are spaced about 0.650 inches (1.65 centimeters) apart. (The function of attachment holes  26 A and  26 B will be described in detail with respect to  FIG. 3 ). Also, in an exemplary embodiment, prongs  24 A and  24 B are about 0.80 inches (2.032 centimeters) in length and about 0.190 inches (0.483 centimeters) in diameter with an outer tip having a diameter of about 0.120 inches (0.301 centimeters). Prongs  24 A and  24 B extend from the distal surface of body  22  and are positioned through a center line extending across the length of body  22 . Prongs  24 A and  24 B are spaced about 1.25 inches (3.175 centimeters) apart. However, it should be understood that the dimensions of second removal and installation head  20  may vary depending on the configuration of the corresponding plasma spray gun component. For instance, in an exemplary embodiment, the length of prongs  24 A and  24 B could range from about 0.5 inches (1.27 centimeters) to about 1 inch (2.54 centimeters) and the distance between prongs  24 A and  24 B could range from about 0.75 inches (1.905 centimeters) to about 1.5 inches (3.81 centimeters). 
         [0018]    Second removal and installation head  20  may be comprised of a metal, such as carbon steel or any other suitable material. In addition, second removal and installation head  20  may be formed of individual parts, which are welded together. In addition, second removal and installation head  20  may also be formed, for example, of a single unitary piece of molded or forged metal. 
         [0019]      FIG. 3  is a perspective view of the second removal and installation head  20  positioned for attachment to first removal and installation head  10 . As described with reference to FIG.  1 , first removal and installation head  10  includes drive socket  16  attached to the proximal surface, which allows drive socket  16  to couple with a wrench (as described in detail with respect to  FIG. 4 ). While first removal and installation head  10  has the ability to couple with a wrench, second removal and installation head  20  has the ability to couple with first removal and installation head  10 . 
         [0020]    As shown in  FIG. 3 , attachment holes  26 A and  26 B extend though body  22  of second removal and installation head  20  and are spaced to receive prongs  14 A and  14 B of first removal and installation head  10 . As a result, prongs  14 A and  14 B may be inserted into attachment holes  26 A and  26 B, which brings the distal surface of first removal and installation head  10  flush with the proximal surface of second removal and installation head  20 , essentially holding first removal and installation head  10  and second removal and installation head  20  in position against each other. In addition, since first removal and installation head  10  is formed of a metal, magnetic layer  28 , which is attached to the proximal surface of second removal and installation head  20 , securely adheres to the distal surface of first removal and installation head  10 . However, the invention is not so limited and second removal and installation head  20  may be attached to first removal and installation head  10  with any suitable method. Once attached, second removal and installation head  20  is positioned so that prongs  24 A and  24 B extend outward. Therefore, second removal and installation head  20  can be utilized as described with reference to  FIG. 5 . 
         [0021]      FIG. 4  illustrates first removal and installation head  10  in use. Wrench  30  is shown coupled to wrench extender  32 . Also shown is rear gun component  40 , which includes cathode  42 , cathode holder  44  and cavities  46 A and  46 B. 
         [0022]    Wrench  30 , which is a standard ⅜-drive ratchet wrench, is coupled to wrench extender  32 . Wrench  30  includes a ratcheting mechanism, which allows a component to be tightened or loosened with a continuous motion. This eliminates the user from having to remove wrench  30  and refit it after each turn. The design of wrench  30  also provides enough torque to remove overtightened components, which eliminates excessive force being applied to the tool. Since removal and installation of plasma gun components is difficult due to the design of conventional plasma spray gun mounting hardware, wrench extender  32  is coupled to wrench  30 , which enables access to difficult to reach components. First removal and installation head  10  is attached to wrench extender  32  by inserting the tip of wrench extender  32  into recess  18  inside drive socket  16 . 
         [0023]    In an exemplary embodiment, first removal and installation head  10  is configured to disassemble and/or assemble rear gun component  40 , which includes cathode  42  and cathode holder  44 . Cavities  46 A and  46 B are positioned in the center of cathode holder  44  and, upon engagement, allow cathode holder  44  to be removed and/or installed. Prongs  14 A and  14 B extend outward from first removal and installation head  10  and are configured to mate with cavities  46 A and  46 B, respectively. As indicated in  FIG. 4  by dashed lines, first removal and installation head  10  is engaged with cathode holder  44  by inserting prongs  14 A and  14 B into cavities  46 A and  46 B. Upon insertion of prongs  14 A and  14 B, body  12  of first removal and installation head  10  fits securely against cathode holder  44 . Wrench  30  can then be used to rotate cathode holder  44  in a clockwise direction if installation is desired or in a counterclockwise direction if removal is desired. The handle of wrench  30  is comfortable for the user to grasp and offers superior mechanical advantage. Once cathode holder  44  is properly installed or removed, first removal and installation head  10  may be disengaged from cathode holder  44 . 
         [0024]      FIG. 5  illustrates second removal and installation head  20  in use. Wrench  30  is shown coupled to wrench extender  32  and first removal and installation head  10  is shown coupled to wrench extender  32 , as described with reference to  FIG. 4 . In addition, second removal and installation head  20  is shown attached to first removal and installation head  10 , as described with reference to  FIG. 3 . Also shown is front gun component  50 , which includes front gun body  52 , nozzle  54 , locking ring  56  and cavities  58 A- 58 D. 
         [0025]    In an exemplary embodiment, second removal and installation head  20  is configured to disassemble and/or assemble front gun component  50 , which includes front gun body  52 , nozzle  54  and locking ring  56 . Cavities  58 A- 58 D are positioned evenly around locking ring  56 , which surrounds nozzle  54 , and upon engagement allow locking ring  56  to be removed and/or installed. Prongs  24 A and  24 B extending from first removal and installation head  10  are configured to mate with cavities  58 A and  58 C or cavities  58 B and  58 D, respectively. As indicated in  FIG. 5  by dashed lines, second removal and installation head  20  may be engaged with locking ring  56  by inserting prongs  24 A and  24 B into cavities  58 A and  58 C. (Second removal and installation head  20  may also be engaged with locking ring  56  by inserting prongs  24 A and  24 B into cavities  58 B and  58 D.) Upon insertion of prongs  24 A and  24 B, body  22  of second removal and installation head  20  fits securely against locking ring  56 . Wrench  30  can then be used to rotate locking ring  56  in a clockwise direction if installation is desired or in a counterclockwise direction if removal is desired. Once locking ring  56  is properly installed or removed, second removal and installation head  20  may be disengaged from locking ring  56 . 
         [0026]    Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.