Abstract:
A multi-part pin remover for removing a pin from a hole of a component is provided. A holder of the pin remover that is supported on the component is equipped with a projection that aligns the pin remover with respect to the component in order to reliably prevent any twisting of the pin when removing the pin from the hole.

Description:
[0001]    This application is the US National Stage of International Application No. PCT/EP2008/053263, filed Mar. 19, 2008 and claims the benefit thereof. The International Application claims the benefits of European Patent Office application No. 07007216.0 EP filed Apr. 5, 2007, both of the applications are incorporated by reference herein in their entirety. 
     
    
     FIELD OF INVENTION 
       [0002]    The invention relates to a multi-part pin remover for removing a pin or stud from a hole of a component, said multi-part pin remover comprising a pull rod that is provided with a thread and a holder that accommodates the pull rod and can be supported on the component for releasing the pin from the component, wherein the pull rod is connectable in a positive locking manner to the pin to be released and, in the state connected to the pin, is displaceable in the pulling direction by rotating a screw nut that is supported on the holder. 
       BACKGROUND OF INVENTION 
       [0003]    Multi-part pin removers for removing a pin or stud from a hole of a component are known in general, such as, for example, in DE 18 53 600 U and DE 20 2006 014 177 U1. The pins usually sit securely in the component and are generally retained by means of friction. The pin, in this case, is frequently recessed so as to be flush and multi-part pin removers are used to release the recessed pin. As a rule, in this case, the pin remover comprises a pull rod that is screw-connectable to the pin to be removed, said pull rod being supportable on the holder and displaceable in its axial direction under the effect of a force to remove the pin. In this case when the pin is being pulled out, the holder of the pin remover is supported on the component, which consequently forms the thrust bearing for the force acting on the pull rod. 
         [0004]    It has proved disadvantageous that when the pin is being pulled out, the holder or the pull rod can tilt relative to the axial direction of the pin, which can result in damage to the component when the pin is being released. The damage can be widening in the region of the opening of the hole. When a replacement pin is inserted, this damage can result in a less secure friction fit between pin and component, which can cause the pin to be released in an unwanted manner from the component. 
         [0005]    If the pin to be extracted is screw-connectable to the pull rod, the thread chamfers of one of the two components can also abrade due to a non-axially parallel arrangement of pin and pull rod so that, where applicable, a pin to be released is no longer removable from the component. 
       SUMMARY OF INVENTION 
       [0006]    It is the object of the invention, consequently, to provide a multi-part pin remover, by means of which damage to the component, from which the pin or stud is to be removed, is reliably avoided. 
         [0007]    Accordingly, another object of the invention is to reduce the abrasive wear on the components of the pin and pull rod participating in the positive locking connection. 
         [0008]    This object is achieved according to the invention through a multi-part pin remover according to the features of the claims. 
         [0009]    The realization underlying the invention is that if the holder has means to align the pin remover relative to the component, both abrasive wear on the components of the pin and pull rod participating in the positive fit and tilting of the pull rod relative to the axial direction of the pin can be reliably avoided. Due to the means provided, the pull rod is always displaced in the pulling direction concentrically to the axial axis of the pin or stud so that abrasive wear at the component caused by tilting can be avoided. Abrasive wear at the components of the pin and the pin remover that form the positive fit can also be reliably avoided, as, on account of the predetermined fixed alignment and positioning of the pin remover relative to the pin, the positive fit can always be brought about as prescribed. 
         [0010]    The holder has a hook-shaped projection as means for aligning the pin remover. The hook-shaped projection, in this case, is matched to the groove depth so that displacement of the pin remover in this direction during the releasing of the pin can be reliably avoided. 
         [0011]    Advantageous developments are provided in the sub claims. 
         [0012]    In an expedient manner, the hook-shaped projection is insertable preferably almost free from play, that is with accuracy of fit, into a groove that is provided on the component. The wall thickness of the hook-shaped projection and the width of the groove are accordingly coordinated with one another. Consequently, there is an error-free alignment of the pin remover where the central longitudinal axis of the pin coincides with the pulling direction of the pin remover. In another advantageous development, the projection provided on the holder extends transversely to the pulling direction. This makes it possible for the holder not to be displaced relative to the component when the pin is being pulled out. 
         [0013]    In particular, it is not possible for the component to tilt about the central axis of the pin. As a result, the hole is not damaged when the pin is released so that pins inserted subsequently are insertable into the hole with unchanged quality, i.e. with an identically reliable friction fit. 
         [0014]    In the case of an advantageous further development of the invention, the projection has an opening for receiving the pin. This means that the projection is divided into two parts on the holder, between which the pin can extend if the groove extends transversely relative to the axial direction of the pin. To produce a simple positive fit between pull rod and pin, the pull rod has a thread that is screw-connectable to the pin. This means that a particularly positive and sufficiently reliable positive locking connection is produced between pin and pin remover in order to remove the pin from the hole. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The invention is explained by way of a drawing, in which: 
           [0016]      FIG. 1  shows an exploded representation of a multi-part pin remover and 
           [0017]      FIG. 2  shows a sectional representation of a pin remover as in  FIG. 1 , screw-connected to a pin. 
       
    
    
       [0018]    Identical components are provided with identical references in all the Figures. 
       DETAILED DESCRIPTION OF INVENTION 
       [0019]      FIG. 1  shows an exploded representation of a multi-part pin remover  10  according to the invention for removing a pin or stud from a hole of a component. The component can be a rotor disc or a gas turbine, for example, as is made known in the European Patent Application with the official number of 07 000 381.9. Through this reference, the object disclosed in the European Patent Application with the official number of 07 000 381.9 is explicitly incorporated into this Patent Application and consequently becomes part of the disclosure of this Patent Application. 
         [0020]    The pin remover  10  comprises a holder  16 , into the opening  14  of which a pull rod  12  can be inserted. The pull rod  12  is provided with at least one first thread portion  18 , to which a screw nut  20  can be screw-connected. 
         [0021]    Along with the opening  14 , the holder  16  comprises a contact face  22 , which can be positioned in a planar manner against the surrounding area of the hole, from which the pin is to be removed. In addition, the holder  16  comprises a hook-shaped projection  24  as means for aligning the pin remover  10  relative to the component, in which projection an additional opening  26  is provided. The free end of the hook-shaped projection  24  extends transversely relative to the pulling direction Z of the pull rod  12 . 
         [0022]    The pull rod  12  comprises a second section  19 , which is provided for producing a positive fit with the pin. The section  19  preferably has a second external thread, which is screw-connectable to a concentric internal thread provided on the pin. 
         [0023]      FIG. 2  shows a cross-sectional representation of the multi-part pin remover  10  in the assembled state and in the state screw-connected to a pin  32 . The pin  32  is recessed in a component  30 , for example in the rotor disc known in the aforementioned European Patent Application and serves to secure a sealing element against displacement in the circumferential direction. 
         [0024]    The pin  32 , in this case, sits in a hole  34 , which extends through a groove  36  that is open at one end and is provided in the component  30 . An internal thread  40  is provided on the end face  38  of the pin  32 , said internal thread being screw-connectable to the thread provided on the second section  19  of the pull rod  12 . The hook-shaped projection  24  of the holder  16 , in this case, is inserted approximately free from play into the groove  36 , the opening  26  provided in the projection  24  engaging the pin  32  at the side. The selected width of the opening  26  corresponds to the external diameter of the pin  32 . On account of the predetermined length of the two portions of the projection  24  flanking the opening  26 , it is possible to position the axis of rotation of the pull rod  12  in an axially parallel and congruent manner relative to the axis of symmetry of the thread  40  of the pin  32 . This reliably avoids the pull rod  12  tilting when being screw-connected to the thread  40  of the pin  32  so that both the external thread provided at the second section  19  and the internal thread  40  of the pin  32  remain undamaged. On account of the components being aligned in such a manner one relative to the other, the pull rod  12  can be screw-connected to the pin  34  in a particularly simple manner. 
         [0025]    Once a necessary screw-in depth has been obtained, the pull rod  12  can then be moved in the pulling direction with the help of the screw nut  20  by rotating the screw nut  20  relative to the pull rod  12 , the screw nut  20  being supported on the holder  16  and the holder  12  being supported on the component  30 . In order to prevent the pull rod  12  also being rotated when the screw nut  20  is rotated, said pull rod can be secured by means of a wrench that can be attached to the head  44  of the pull rod  12 . 
         [0026]    On account of the form-locked seat of the holder  16  in the component  30 , a tilting of the holder  16  can also be reliably avoided when the pin  30  is being pulled out. Consequently, damage to the hole  35  in the component  30  can be reliably excluded so that replacement pins inserted subsequently are retained to the same extent as the pins initially inserted and are retained free from play.