Abstract:
A method and a device for straightening out irregularities in a flange by pressing a roller against a first side of the flange while supporting an opposite side thereof to preserve the angle between the flange and the part when undergoing compression loading by way of the roller.

Description:
TECHNICAL FIELD 
   The invention relates generally to engine parts and, more particularly, to an improved method for restoring a flange of an engine part and device for doing same. 
   BACKGROUND OF THE ART 
   A current approach for reworking flanges of various engine parts involves brute force bending the flange at discrete locations with a mechanical hand press. There are numerous disadvantages to the device and process involved. A first disadvantage is that it is significantly dangerous for employees to operate the hand press due to the excessive effort required to obtain the desired result. Several recorded accidents and numerous unrecorded incidents have occurred. Consequently, many operators refuse to do the job claiming that the working conditions are unacceptable. 
   A second disadvantage is that the quality of restoring flanges, within a particular tolerance, using the above-mentioned device is inconsistent. This is largely due to the fact that the pressure applied by the operator is not readily measurable, thus, results may vary considerably. More specifically, the application of pressure on a flange is determined by the effort applied on the handle of the device by the operator. In an attempt to gain the last thousandths of the tolerance, an operator may surpass the acceptable limit. Furthermore, the weight of the operator is a determining factor of the amount of pressure applied; hence, diverse operators yield varying outcomes resulting in inconsistent quality. 
   A third disadvantage is that the turn around time relevant to the use of the mechanical hand press and corresponding method involved is extensive due to the numerous secondary operations required known in the art. 
   Accordingly, there is a need to provide an improved device and method for restoring a flange of an engine part so as to overcome the disadvantages set forth of the presently known device. 
   SUMMARY OF THE INVENTION 
   It is therefore an object of this invention to provide a method of restoring a flange which addresses the above-mentioned concerns. 
   In one aspect, the present invention provides a method of restoring a flange which has become distorted over time, the flange projecting at an angle from a component part, the method comprising the steps of: a) providing a support element on a first side of the flange, rolling a load applying element over a second opposite side of the flange with said support element reacting the compressive loads applied by said load applying element on said flange; and maintaining the angle between the flange and the component part during load application by way of the support element. 
   In another aspect, the present invention provides a method of restoring a flange extending at an angle from a part, the method comprising the step of: straightening out irregularities in the flange by pressing a roller against a first side of the flange while supporting an opposite side thereof to preserve said angle between the part and the flange when undergoing compression loading by way of said roller. 
   In another aspect, the present invention provides a method of flattening a circular radial flange, comprising the steps of: a) applying a flattening load to one side of the flange sequentially around a circumference of the flange, and b) providing a plurality of ring segments on an opposite side of the flange to oppose the flattening load. 
   In another aspect, the present invention provides a device for straightening out irregularities in a flange projecting at an angle from a part, comprising a roller for applying a flattening load against a first side of the flange, and a fixture for holding the part to be reworked, the fixture having a seat against which a second opposed side of the flange is supported to preserve the angle of the flange relative to the part while undergoing compression loading by way of said roller, said roller and said seat being relatively movable towards and away from each other, said roller being displaceable relative to said seat in a plane parallel thereto once pressed against the flange to apply a compressive load perpendicularly to the seat along the perimeter of the flange. 
   Further details of these and other aspects of the present invention will be apparent from the detailed description and figures included below. 

   
     DESCRIPTION OF THE DRAWINGS 
     Reference is now made to the accompanying figures depicting aspects of the present invention, in which: 
       FIG. 1  is a perspective assembled view of the flange restoring device operated to straighten a flange of an engine part to be restored in accordance with an embodiment of the present invention; 
       FIG. 2  is a schematic view of the flange restoring device shown in  FIG. 1 ; 
       FIG. 3  is a perspective view of the engine part in a fixture on a rotary table forming part of the device shown in  FIG. 1 ; 
       FIG. 4  is a perspective view of a plurality of torus segments being installed underneath the flange to be reworked; 
       FIG. 5  is a sectional view of one of the torus segments shown in  FIG. 4 ; 
       FIG. 6  is a perspective view of a containment ring being installed about the torus segments; 
       FIG. 7  is a sectional view of the flange restoring device shown in  FIG. 1 ; 
       FIG. 8  is a perspective view of a hand wheel being operated to position a load applying roller over the flange of the engine part to be reworked; 
       FIG. 9  is a perspective view of the control box of the flange restoring device in  FIG. 1 ; and 
       FIG. 10  is a perspective view of a hydraulic hand pump of the flange restoring device in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  illustrates a device  10  for restoring a flange  12  of a gas turbine engine part  14 , such as a turbine exhaust duct. It is understood however that the present flange straightening method could be used for straightening out irregularities in flanges of a wide variety of component parts. In an exemplary embodiment of the present invention shown in  FIG. 2 , the engine part  14  is made up of a cylindrical body  16  and a bent circular radial flange  12  requiring straightening. In detail, the flange  12  has a rectangular cross section substantially perpendicular to the cylindrical body  16  as best illustrated in  FIG. 2 . The flange  12  can be described as having a first surface  18  opposing a second surface  20  circumscribed by a perimeter  22 . In this particular case, the first surface  18  is the top surface while the second surface  20  is the bottom surface or underneath of the flange  12 . It should be noted that alternative flange configurations are also possible. For example, the flange  12  could have a conical cross section or could be circular yet discontinuous around the circumference of the cylindrical body  16 . Moreover, the device  10  could be designed to accommodate engine parts of varying shape without departing from its inventive nature. 
   Essentially, the device  10  restores the flange  12  by cold reworking it to its original form within given tolerances without the removal of material. As shown in  FIG. 1 , the flange restoring device  10  includes an “H” frame press  24  similar to any conventional press known in the art, which supports a hydraulic roller  26  movable for proper positioning with respect to the flange  12  by way of a hand wheel  28  ( FIG. 8 ). The device  10  further includes a hydraulic hand pump  30  (as best shown in  FIG. 10 ) for generating a measurable amount of pressure required to straighten the flange  12  and a control box  32  ( FIG. 9 ) having a programmable logic controller (P.L.C.), a timer, failsafe cycle start controls and a power cut-off. 
   Referring to  FIGS. 1 and 3 , a turn table  34  with a vertical central axis  36  ( FIG. 3 ) of rotation is also included as part of the device  10  for restoring the flange  12 . The turn table  34  must be durable for repeatedly withstanding high loads that need to be sustained in order to rework the flange  12 . The rotary table  34  is preferably electrically driven and controllable by the control box  32 . 
   The device  10  further includes a fixture  38  adapted for receiving the engine part  14  and for permitting the straightening of the flange  12  in both the radial and the axial directions through the use of a pressure applied by the hydraulic roller  26  as illustrated in  FIG. 2 . More specifically, the fixture  38  as depicted in  FIG. 3  receives the cylindrical body  16  such that a portion of the cylindrical body  16  with the flange  12  protrudes upwardly therefrom. The fixture  38  is securely mounted on the rotary table  34 . It is preferably centered about the central axis  36  of the rotary table  34  allowing for the center of the engine part  14  to align therewith upon insertion into the fixture  38 . By aligning the centers of the rotary table  34 , the fixture  38  and the engine part  14  a balance and stability is created, which is beneficial when load application is involved. As an exemplary embodiment the fixture  38  is cylindrical for simplifying the inclusion of the cylindrical body  16 , the latter fitting snugly within the fixture  38 . 
   Referring now to  FIGS. 2 , the device  10  also includes at least one seat or support element  40  for supporting the second surface  20  or underneath of the flange  12  to react the load on the first surface  18  applied by the hydraulic roller  26  during operation of the device  10 , as will be described in detail hereinafter. The fixture  38  is adapted to receive the support element  40 , acting as a base configured to mate with the latter. 
   In the illustrated embodiment, the support element  40  comprises a discrete number of torus or toroidal segments  42  (see  FIGS. 4 ,  5  and  7 ). A primary feature of the torus segments  42  is that they permit for a flexible support of the flange  12 : yielding the flexibility required to bend the flange  12  in order to straighten it. More particularly, each torus segment  42  has the ability to flex or tilt towards or away from the central axis  36  of rotation and also expand in the tangential direction along the circumference of the cylindrical body  16  as the engine part  14  is rotated and the pressure is applied. In practice, the segments  42  themselves do not move outwards but rather (thru the use of an adequate lubricant) permit the flange  12  to slide across as required to straighten out the bends. Preferably, the torus segments  42  are spaced equidistantly around the circumference of the cylindrical body  16  as best illustrated in  FIG. 4 . If the spacing between the torus segments  42  is too great the flange  12  may potentially bend in an unwanted form when loaded, particularly at the locations lacking support. Hence, by equally spacing the torus segments  42  the possibility of having a gap that exceeds the acceptable limit is avoided. 
   Referring concurrently to  FIGS. 4 ,  5  and  7 , the torus segments  42  will now be described in detail. As depicted in the above-specified Figures, the torus segments  42  each include a core  44  with a radially outwardly protruding piece  46  attached thereto. The core  44  has a toroidal cross section (somewhat semicircular cross section) and can be further defined as having a flat top, a curved bottom, an inside and an outside surface  48 ,  50 ,  52  and  54  respectively. The protruding piece  46 , whose function will become clear later on, is attached to the outside surface  54  of the core  44 . 
   In this exemplary embodiment, the piece  46  is attached by way of being press fit and bolted into an aperture (not shown) present in the outside surface  54  of the core  44  and is preferably centered with respect to the outside surface  54  ( FIG. 7 ). However, it should be noted that alternatives attachment means and locations are also possible so long as the flexibility of the torus segments  42  is not hindered. Similarly, the shape of the protruding piece  46  can also vary. In this embodiment it is depicted as a cylindrical type piece, but other configurations could work as well. 
   Referring now particularly to  FIGS. 5 and 7 , it can be seen that the bottom surface  50  of the core  44  has a convex curvature designed to sit atop the fixture  38  that has a matching concavity for receiving the bottom surface  50 . The top surface  48  of the core  44  is shaped to contact the second surface  20  or underneath of the flange  12  such that the top surface  48  is flush with the flange  12 . Hence, the core  44  is designed to achieve the greatest number of contact points possible with the flange  12  so as to maximize the support capabilities. 
   Furthermore, the inside surface  52  of the core  44  is also designed to mate with the portion of engine part  14  protruding from the fixture  38  as can be seen in  FIG. 5 . In the illustrated case, the inside surface  52  has a slot  56  along the longitudinal axis of the core  44  to engage with a male feature of the cylindrical body  16  particular to the exemplified engine part  14  illustrated in  FIGS. 4 and 7 . Notably, this is merely an example of the configuration of the core  44  as the engine part  14  requiring work can vary in shape. Thus, it can be stated that the core  44  is propitiously suited for engagement with the fixture  38  and the protruding engine part  14  so as to maximally support the flange  12 , whereby the support in mention is a flexible type of support. 
   In addition,  FIGS. 4 ,  5  and  7  show the core  44  as having a bore  58  along its longitudinal axis. The bore  58  is adapted to receive a large O&#39;ring to be threaded thru the segments  42  to keep them together as a unit. Bore  58  is optional only. 
   It should be understood that the engine parts to be reworked are analyzed on a case-by-case basis to determine the type of tooling required to yield the greatest efficiency. Thus, depending on the type of material and the nature of the rework requirements, a simple flat ring could be used instead of the torus segments  42  above-described to support the flange  12 . 
   Now referring concurrently to  FIGS. 2 ,  6  and  7 , containment ring  60  included as part of the flange restoring device  10  is illustrated. The containment ring  60  is multifunctional in that it: acts to prevent the expansion by centrifugal force of the flange  12  in an outer radial direction after the engine part is loaded into the fixture, it serves to ensure that the torus segments  42  are equidistantly spaced, preventing an excessive gap at any one spot along the circumference of the cylindrical body  16 , and it also contains the segments  42  in the event of a catastrophic failure. 
   The containment ring  60  is adapted to engage the torus segments  42  upon installation thereby circumscribing the perimeter  22  of the flange  12 . In this exemplary embodiment, the containment ring  60  is provided in the form of a circular member having an inner side  62  and an outer side  64  defining a discrete number of downwardly open ended apertures  66  therebetween: The number of apertures  66  corresponds to the number of torus segments  42  each having a cylindrical protruding piece  46 . Particularly, the apertures  66  are of a U-shape so as to engage with the protruding cylindrical pieces  46  such that the latter slot into the apertures  66  upon proper positioning of the containment ring  60 . 
   Furthermore, upon installation of the containment ring  60 , the inner side  62  thereof comes into contact with the perimeter  22  of the flange  12  and the torus segments  42  ( FIG. 2 ). Notably, the containment ring  60  could alternatively be designed to additionally come into contact with the fixture  38  as best demonstrated in  FIG. 7 . 
   Now referring concurrently to  FIGS. 2 and 7 , a wear pad  68  of the type commonly known in the art is included to act as an intermediary load distributing element. The wear pad  68  ensures that the pressure applied by the hydraulic roller  26  to the first surface  18  of the flange  12  does not mark the engine part  14  and that the load is distributed evenly thereacross. The wear pad  68  is placed between the hydraulic roller  26  and the flange  12  on top of the first surface  18  of the flange  12 . 
   It is preferable that the wear pad  68  be at least as wide as the first surface  18  of the flange  12  to cover the entire flange  12  for protection. Also, for security purposes the wear pad  68  should abut the inner side  62  of the containment ring  60  as illustrated in  FIGS. 2 and 7 . The wear pad  68  can be made of a variety of materials able to repeatedly withstand loading: steel being commonly utilized. 
   METHOD OF RESTORING A FLANGE OF AN ENGINE PART 
   The principal function of the flange restoring device  10  is to rework the flange of an engine part without the removal of material so that the engineering requirements for repair are met. 
   Firstly, the engine part  14  is properly inserted in the fixture  38  followed by the instalment of the support element  40  ( FIGS. 3 and 4 ). In the case where the torus segments  42  are utilized, they are each individually inserted between the underneath  20  of the flange  12  and the portion of the fixture  38  configured for mating therewith. Also, the torus segments  42  are positioned against the portion of the cylindrical body  16  protruding from the fixture  38 . 
   Next, the containment ring  60  is installed so as to sit on the radially protruding pieces  46  of the torus segments  42  by way of the U-shaped apertures  66 . The latter, being equidistantly spaced around the containment ring  60  ensure that the torus segments  42  are accurately placed and keep them in position ( FIG. 6 ). 
   Next, the wear pad  68  is installed over the flange  12  abutting the containment ring  60  to act as an intermediary load distributing element. The hydraulic roller  26  is then moved into position over the flange  12  by way of the hand wheel  28  ( FIG. 8 ). The hydraulic roller  26  is then lowered to come into contact with the wear pad  68  ( FIG. 1 ). At this point the controls in the control box  32  are activated appropriately ( FIG. 9 ). And finally a measurable amount of hydraulic pressure is manually applied by way of a hydraulic hand pump  30  ( FIG. 10 ). Pressures between 1000 to 1500 lbs are applied depending on the condition of the part to be reworked. 
   In restoring the flange  12 , the hydraulic roller  26  applies a force that is preferably perpendicular to the flange  12  as illustrated in  FIG. 2 . The turn table  34  is electrically driven to rotate the engine part  14  about its central axis  36  at a constant speed, thereby causing the roller  26  to roll over the flange  12 . 
   As the force is applied sequentially around the circular radially flange  12 , the torus segments  42  provide a flexible support to the flange  12  throughout the reworking process. In further detail the torus segments  42  have the ability to individually tilt towards or away from the central axis  36  of rotation as they have a convex curvature that is seated on a concave portion of the fixture  38 . The segments  42  tilt to allow the flange  12  to slide across the flat surface on the top of the segments  42 . Thus, a flexible means of supporting the flange  12  is advantageous in reworking particular materials such as Inconel 600 or 625 that are very tough to work having been distorted by heat and hardened by repeated stresses. 
   The new method of restoring a flange of an engine part is advantageous in that a significant number of operations have been eliminated permitting to process engine parts within a controlled environment yielding improved results. Furthermore, engine parts can be processed within a given time frame while still reducing the overall cost of the rework thereby ensuring customer satisfaction. Moreover, the above-described method also ensures the safety of the employees.
         The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without department from the scope of the invention disclosed. For example, the hydraulic roller could potentially be rotated around the flange rather than having the turn table rotates the engine part. In another example, the flange restoring device above described could be modified to accommodate engine parts and flanges of various shapes. In a further example, the entire process of restoring a flange could be automated thus eliminating the necessity of an individual applying pressure by a hydraulic hand pump or installing the torus segments and containment ring. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.