Abstract:
A repair jig for drilling and retapping bores provided in a marine engine distributor is disclosed. The repair jig includes a frame having a plurality of alignment mechanisms operatively associated therewith. Bores formed in the alignment mechanisms are alignable with bores of the marine engine distributor. Once aligned, drill bits and taps can be sequentially inserted through the repair jig and into the distributor for removing broken fasteners and retapping the distributor bores, respectively.

Description:
FIELD OF THE INVENTION 
     The invention generally relates to repair jigs and, more particularly, relates to repair jigs and other apparatus for repairing marine engine distributors. 
     BACKGROUND OF THE INVENTION 
     In the repair or maintenance of marine engine distributors, it is necessary to remove the engine distributor cap from the distributor housing. With certain marine engines, the distributor cap is manufactured from plastic, and is attached to an aluminum distributor housing with steel screws. For example, the Mercruiser Thunderbolt™ series of engines is one example of a distributor comprised of multiple materials. 
     Due to the interaction between the steel and aluminum, as well as the wet environment in which the engine operates, the steel screws attaching the distributor cap to the distributor housing can often corrode. As a result, when an engine mechanic attempts to remove the screws for removal of the cap, the screws tend to seize and break off within a bore of the distributor housing. 
     When such screws break, this necessitates that the mechanic drill the broken screw or screws from the distributor housing, which in turn requires that the distributor housing be retapped to provide the threads necessary for a new screw to be used during reinstallation of the distributor cap. This process has proven to be extremely difficult to accomplish without damaging the distributor cap and/or housing. Even if the distributor housing is not damaged, the process is time consuming and costly. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the invention, a repair jig for drilling and retapping bores provided in a marine engine distributor is provided which comprises a frame, a plurality of alignment collets extending from the frame, and a registration surface provided on each alignment collet. Each collet includes an aperture therethrough. Each registration surface is adapted to engage a receiving surface of the marine engine distributor, such that the collet apertures are aligned with the engine bores upon engagement of the collet registration surfaces with the marine engine distributor receiving surfaces. 
     In accordance with another aspect of the invention, a method of redrilling and tapping bores of a marine engine distributor is provided which comprises the steps of placing a repair jig atop the distributor wherein the repair jig has at least one drill bit alignment opening sized to receive a drill bit and at least one tap alignment opening sized to receive a tap, aligning the drill bit opening with a fastener to be removed from the marine engine distributor, inserting a rotating drill bit through the drill bit opening to remove the fastener from a bore of the distributor, aligning the tap opening with the bore, and inserting a rotating tap into the tap opening and into the distributor bore to retap the bore. 
     In accordance with another aspect of the invention, a kit for repairing a marine engine distributor having at least one distributor cap attachment fastener broken off within a distributor bore is provided which comprises a frame, an alignment mechanism, a drill bit, and a tap. The frame includes at least one drill bit receiving bore and at least one tap receiving bore. The alignment mechanism is operatively associated with the frame and is adapted to align the drill bit receiving bore and the tap receiving bore with the distributor bore. The drill bit is sized to remove the broken fastener, and the tap is sized to rethread the distributor bore. 
     These and other aspects and features of the invention will become more apparent from following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of an engine distributor with a distributor cap attached thereto; 
     FIG. 2 is a top view of the distributor of FIG. 1 illustrated with the distributor cap removed; 
     FIG. 3 is a top view of the repair jig constructed in accordance with the teachings of the invention; 
     FIG. 4 is an exploded view of a distributor, a repair jig, and a drill bit and/or tap; 
     FIG. 5 is a cut-away sectional view of the repair jig placed atop the distributor with a drill bit extending therethrough; 
     FIG. 6 is a top view of an alternative embodiment of a repair jig constructed in accordance with the teachings of the invention; and 
     FIG. 7 is a top view of a second alternative embodiment of a repair jig constructed in accordance with the teachings of the invention. 
    
    
     While the invention is susceptible to various modifications and alternative constructions, certain illustrative embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed but, on the contrary, the intention is to cover all modifications, alternative constructions and equivalents falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, and with specific reference to FIG. 1, an engine distributor, the repair of which is the general field of the invention, is generally depicted by reference numeral  20 . While the distributor  20  is generally depicted as a distributor for a marine engine (not shown), it is to be understood that the teachings of the invention can be employed with respect to additional types of engines as well. 
     As is conventional, the distributor  20  includes a housing  22  to which a distributor cap  24  is secured with threaded fasteners  26 . A shaft  28  extends through the housing  22 . 
     Referring now to FIG. 2, the distributor housing  22  is shown to include a substantially cylindrical opening  30  having a circular flange  32  which mates with a similarly shaped flange  33  of the distributor cap  24  (FIG.  1 ). Spaced around the perimeter of the flange  32  are a plurality of semicircular recesses  34 . Mounting feet  36  radially extend from the distributor housing  22  proximate each of the recesses  34 . The mounting feet  36  include internal threads  38  which are adapted to mate with external threads (not shown) provided on each threaded fastener  26  in order to secure the distributor cap  24  to the distributor housing  22 . 
     In the event that one of the threaded fasteners  26  breaks off within one of the mounting feet  36 , a repair jig  42  constructed in accordance with the teachings of the invention can be employed. As shown in FIG. 3, the repair jig  42  includes a frame  44  with a plurality of alignment mechanisms  46 . In the preferred embodiment, the frame  44  is substantially circular or annular in shape and includes planar top surface  48 , planar bottom surface  50 , circular outer diameter surface  52  and circular inner diameter surface  54 . It is to be understood that in alternative embodiments, alternative shapes for the frame  44  can be used including the semicircular shape depicted later herein. 
     In the preferred embodiment, the alignment mechanisms  46  are provided in the form of collets  56 . Each collet  56  is substantially cylindrical in shape and includes a central bore  58  therethrough. In horizontal cross-section, each collet  56  is therefore annular in shape. Each collet  56  includes a planar top surface  60 , a planar bottom surface  62 , a circular outer diameter surface  64 , and a circular inner diameter surface  66 . 
     In the preferred embodiment, four such collets  56  are employed, although it is to be understood that in alternative embodiments, a different number of collets  56  may be used, with as few as two collets  56  being possible. In the depicted embodiment, two of the collets  56  include bores  58  which are sized to receive a drill bit  68 , while two of the bores  58  are sized to receive a tap  70 . 
     In order to store the drill bit  68  and tap  70  in a convenient manner, the frame  44  may include first and second storage compartments  72  and  74  (FIG.  4 ). In the preferred embodiment, the storage compartments  72  and  74  are provided in the form of recesses bored into the frame  44  and which are sized to frictionally receive the drill bit  68 , and tap  70 , respectively. Additionally, an elastomeric member such as a rubberband may be secured around the circumference of the frame  44  to additionally secure the drill bit  68  and tap  70  within the frame  44 . 
     In operation, when it is desired to remove a threaded fastener  26 , the repair jig  42  can be positioned onto the distributor housing  22  as shown best in FIG.  4 . The repair jig  42  is rotated appropriately to align the alignment mechanisms  46  with the recesses  34 . In so doing, the bores  58  within each collet  56  automatically align with the threaded opening of each mounting foot  36 . Initially, one of the collets  56  having a bore  58  sized to receive the drill bit  68  is aligned with the threaded fastener  26  and the drill bit  68 , powered by a source of rotational power, such as a power or hand drill is inserted through the bore  58  and through the housing  22  to remove the threaded fastener  26 . Once the distributor fastener  26  is removed, the repair jig  42  is rotated to align one of the collets  56  having a bore  58  sized to receive the tap  70  into alignment with the bore created by the drill bit  68 . The tap  70  therefore forms threads in the mounting foot  36  as best shown in FIG.  5 . 
     The repair jig  42 , drill bit  68 , and tap  70  may be provided in a single package or kit  76  to facilitate storage and usage. 
     Referring now to FIG. 6, an alternative embodiment of the invention is depicted. The alternative embodiment includes a frame  78  which is substantially semicircular in shape. Semicircular frame  78  includes first and second collets  80  which are identical to the collets depicted in FIGS. 2-5. Accordingly, the outer surface  82  of each collet  80  defines a registration surface which is adapted to engage the complementary shaped recess  34  provided in the distributor housing  22 . Such an arrangement provides a convenient mechanism by which the repair jig  42  can be easily aligned with the distributor housing  22 . 
     Referring now to FIG. 7, a second alternative embodiment of the invention is depicted wherein a frame  83  is provided with a plurality of alignment openings  84 . Rather than employing collets  56 , the alternative embodiment aligns the frame  82  with the distributor housing  22  simply by inserting fasteners, such as threaded screws and bolts, through the openings  84  and into an opening of one of the mounting feet  36  in repair. In so doing, one of the openings  84  will be aligned with the foot  36  needing repair. The drill bit  68  and tap  70  then can be sequentially inserted as described above. 
     From the foregoing, one of ordinary skill in the art will appreciate that the invention provides an apparatus and method for repairing a marine engine distributor which improves accuracy, reduces distributor damage, and lessens repair time and cost.