Abstract:
A tool for the removal of a broken heater hose coupler from an engine block includes a symmetrical driving tool with twelve teeth or splines for engagement with the broken coupler so that a wrench may be applied to the opposite end of the tool to twist and unthread the coupler from the engine block.

Description:
BACKGROUND OF THE INVENTION 
     In a principal aspect, the present invention relates to a specialized tool for removal of a broken heater hose coupler from an engine block. The tool is formed with a special array of splines that may be driven into the broken heater hose coupler to provide for gripping of the coupler in a manner which facilitates rotation and removal of the broken coupler from the block. 
     The heater hose connection for many motor vehicles is often attached to the engine block by means of a coupler. Some couplers are made from steel, but most are made of die cast zinc. Typically, couplers are in the form of a tube with outside threads at one end that screw into the block. The opposite end typically includes a hose clamp or bayonet connection for a hose. 
     The die cast zinc couplers often corrode and break along the thread line where the coupler is attached to the engine block. A broken coupler must, therefore, be replaced, but cannot be removed in a conventional manner by unscrewing the coupler from the block inasmuch as the threaded section of the coupler is lodged in the block and the portion projecting from the box has been broken and removed. Thus, there has developed a need to provide a means and tool for removal of a die cast zinc, threaded coupler section remaining within the threaded opening in the engine block. 
     SUMMARY OF THE INVENTION 
     Briefly, the present invention comprises a tool for removal of a broken heater hose coupler from an engine block. A projecting portion of the coupler has been broken and a threaded section remains in the block but cannot be removed by conventional means, for example, unthreading by means of a wrench, pliers or the like. The tool of the invention comprises an elongate rod having a polygonal shank at one end and a plurality of substantially identical splines at the other end. Twelve splines are symmetrically arranged around a longitudinal axis at the working end of the tool. The spline, working end portion of the tool is divided into two sections; namely, a mid region and an end region. The splines in the mid region are crested by walls joined at an apex and having a triangular cross section; whereas the splines in the end region have a truncated cross section. The opposite polygonal end of the tool includes a surface for driving the tool into the portion of the coupler remaining in the engine block. The shape or configuration of the splines enables the tool to effectively and efficiently interface and grip the coupler section so that a wrench or other tool may be applied to the polygonal end of the tool to impart rotation and removal of the coupler section. 
     Thus, it is an object of the invention to provide an improved tool for removal of a broken heater hose coupler from an engine block. 
     It is a further object of the invention to provide a tool for removal of a broken heater hose coupler from an engine block which may be driven into the coupler section in the engine block to thereby grip the coupler section so that it may be twisted or turned and unthreaded from the block. 
     Another object of the invention to provide a tool for removal of a broken heater hose coupler from an engine block which includes twelve, symmetrical splines arranged a uniform radial distance from the center line longitudinal axis of the tool and wherein each of the splines has a substantially identical construction thus providing a symmetric configuration and cross section. 
     It is a further object of the invention to provide a rugged, inexpensive and highly efficient tool for removal of a broken heater hose coupler from an engine block. 
     These and other objects, advantages and features of the invention will be set forth in the detailed description which follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In the detailed description which follows, reference will be made to the drawing comprised of the following figures: 
     FIG. 1 is a side elevation of the tool of the invention; 
     FIG. 2 is an end view of the tool of FIG. 1; 
     FIG. 3 is a cross sectional view depicting the configuration of the splines in the mid region of the tool; 
     FIG. 4 is a cross sectional view taken along the line of  4 — 4  in FIG. 1; 
     FIG. 5 is an isometric view of the tool of FIG. 1; and 
     FIG. 6 is an isometric view illustrating the use of the tool of FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the figures, the tool is generally symmetrical around a longitudinal, center line axis  10 . The tool thus includes a shank end  12  having a generally polygonal cross section, for example, a hexagonal cross section, so that it may be easily driven or turned by a wrench or similar tool. A transverse planar flat driving surface  14  is preferably perpendicular to the axis  10 . Preferably, the tools are approximately two (2) inches in length along the longitudinal axis  10  and the shank section or shank  12  comprises approximately one-half of that dimension, or one (1) inch. 
     The opposite end of the tool comprises a spline section  16  which is adapted to engage the broken portion of a hose coupler in an engine block as described hereinafter. The spline section  16  is symmetric about the center axis  10  and includes a mid section  18  and an end section  20 . The mid section  18  and end section  20  comprise twelve identical splines, for example, spline  22 . In the mid section as depicted in FIG. 3, the spline  22  includes an apex  24 , a first diverging sidewall or face  26  and a second diverging sidewall or face  28 . Adjacent diverging faces  29 ,  28  of adjacent splines  22  intersect at a 90° angle or a right angle. Adjacent converging faces  26 ,  28  intersect at a 60° angle. Thus, the splines  22  comprise pointed teeth or ribs in cross section in the mid region  18 . The ribs, teeth or splines  22  are arrayed symmetrically about the center line axis  10 . Thus, each quarter section of the cross section of the tool includes three splines or teeth  22 . The apex, crest or peaks  24  of each of the teeth  22  have equal radii, R 2 . The valley  25  between each tooth  22  is defined by a second radius R 1 . 
     FIG. 4 depicts the cross section of the construction associated with the end section or portion  20  of the spline section  16 . Thus, FIG. 4, as well as FIG. 2, illustrates the cross sectional shape of the tool along the line  4 — 4 . The splines or teeth, or ribs  22  of end section  20  are extensions or continuations of the teeth  22  associated with the mid section  16 , except that the teeth  22  in end section  20  are truncated in cross section by virtue of a radius surface  40  having radius R 3  which connects opposite faces  26 ,  28  of each tooth or spline  22 . The amount of truncation is approximately ⅓ of the depth of the rib or tooth  22  to define a radius R 2 . Thus, the truncated section  42  of tooth  22  is defined by three surface facets, or faces; namely, the partial faces  26 ,  28  and the truncated face  40 . 
     The longitudinal extent of the end section or truncated tooth section  20  is approximately one-half of the longitudinal extent of the midsection  18 . A typical radius R 2  associated with the apex  24  is in the range of 0.23±0.005 inches. 
     As depicted in FIG. 6, the manner of use of the tool requires positioning the ribbed or splined sections  18 ,  20  into the portion of the broken coupler  50  retained within the engine block  52  in a manner which aligns the axis  10  with the center line axis  54  of the coupler  50 . The tool is then driven down into the coupler  50  in a manner which engages the crests of the peak  24  of the teeth  22  with the coupler  50 . That is, the truncated portions or section  20  of the ribs, teeth or crest  22  form an initial guide mechanism or pathway for movement of the tool into the opening defined by the broken coupler  50 . The crest  24  of the teeth  22  then will be driven into the coupler  50  by engaging a hammer  53  against the surface  14 . Thereafter, a wrench, pliers or the like is gripped on the polygonal head  12  and the coupler  50  is unthreaded from the engine block. 
     Variations of the tool may be implemented. For example, the size and array of the teeth may be varied slightly. Twelve teeth or ribs are preferred. The dimensions of the teeth or ribs may be varied including the longitudinal dimensions as well as the radial dimensions. The shank may be polygonal or include other internal or external drive/rotation configurations. Thus, the invention is to be limited only by the following claims and equivalents thereof.