Abstract:
A tool useful for engaging and pivoting the rocker arm of an internal combustion engine in order to enable removal of a push rod from the engine by virtue of positioning the rocker arm in a manner that disengages the rocker arm from the push rod includes a pair of bifurcated arms which fit on opposite sides of the rocker arm and further includes cross members connecting the bifurcated arms which engage the rocker arm in a manner that facilitates manual rotation of the tool and the rocker arm.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This is a utility application derived from, incorporating by reference and claiming priority to provisional application, Ser. No. 60/701,575 filed Jul. 22, 2005 entitled “Push Rod Removal Tool”.  
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to a tool useful for effecting removal of a push rod from an internal combustion engine block.  
         [0003]     Typically, multiple stroke internal combustion engines include push rods which are mechanically linked to valves that open and close ports to the cylinders of the engine. Most often, each push rod is reciprocally driven in response to actuation by a rotating cam. The opposite end of each push rod typically engages a rocker arm which is biased into engagement with the push rod. Thus, as the cam rotates, the push rod reciprocates causing the rocker arm to pivot against the biasing force of a spring and thereby open various valve ports of the internal combustion engine.  
         [0004]     A repair operation often necessary with respect to internal combustion engines is replacement of the intake manifold gasket. On some engines the push rods must be removed to allow the gasket surfaces to be cleaned and the new gasket installed. Removal of push rods from an internal combustion engine, however, is not a straightforward mechanical operation. Various means must be employed in order to move the rocker arm out of engagement with the push rod so that the push rod may be effectively removed and replaced. Factors which complicate replacement may include the time and effort to remove parts of the engine in order to secure adequate access to the push rods. An effective, efficient and simple means for removal of push rods thus is an objective long sought by engine mechanics.  
       SUMMARY OF THE INVENTION  
       [0005]     Briefly, the present invention comprises a tool for engaging and biasing the rocker arm associated with an engine push rod in a manner which enables pivotal movement of the rocker arm out of engagement with the push rod so that the push rod may be easily removed and replaced. The tool is comprised of spaced, bifurcated lever arms which are joined together by means of transverse connecting or bridging members spaced from one another. The transverse or bridging members are designed to engage the rocker arm on opposite sides of the rocker arm pivot axis and thereby enable movement of the lever arm to effect rotation of the rocker arm out of engagement with the push rod. In this manner, by rotating the rocker arm about its axis and out of engagement with the push rod, the push rod may be removed from the engine block or easily replaced in the engine block.  
         [0006]     In a preferred embodiment, the bifurcated spaced lever arms are positioned in opposite sides of the rocker arm and the transverse or cross members connecting the lever arms are engaged against the rocker arm on opposite sides of the pivot axis of the rocker arm so that the lever arms may be manually rotated thereby pivoting or rotating the rocker arm about its axis. The lever arms also include a means for effective extension of the lever arms by engagement with a socket wrench or socket lever. Further, the lever arms are in the form of flat blades that are notched in a manner which facilitates their use without removal or dislocation of various engine components such as valve covers.  
         [0007]     Thus, it is an object of the invention to provide an improved tool capable of effecting rotational movement to an internal combustion rocker arm in order that the associated push rod for the internal combustion engine can be removed thus facilitating the necessary repair work.  
         [0008]     A further object of the invention is to provide a tool which enables a mechanic to apply a mechanical advantage to pivot a rocker arm of an internal combustion engine.  
         [0009]     Yet another object of the invention is to provide a rugged, yet economical tool useful for engaging a rocker arm in order to effect removal of a push rod from an internal combustion engine.  
         [0010]     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  
       [0011]     In the detailed description which follows, reference will be made to the drawing comprised of the following figures:  
         [0012]      FIG. 1  is a top plan view of the push rod removal tool of the invention;  
         [0013]      FIG. 2  is a side elevation of the tool of  FIG. 1 ;  
         [0014]      FIG. 3  is a side elevation of the tool of the invention positioned on the head of a vehicle engine in engagement with a rocker arm of the internal combustion engine;  
         [0015]      FIG. 4  is a partial cutaway view of the tool of  FIG. 1  depicting the manner in which the rocker arm is engaged by the tool;  
         [0016]      FIG. 5  is an isometric view of the tool of the invention that has been manipulated to compress the rocker arm spring so as to enable removal of a push rod from an internal combustion engine; and  
         [0017]      FIG. 6  is an isometric view of the tool of the invention illustrating the manner of use and illustrating further the incorporation of a driver in combination with the tool in order to provide additional mechanical advantage when using the tool.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]      FIGS. 1 and 2  illustrate the tool of the invention. The remaining  FIGS. 3-6  illustrate the utility and function of the tool of the invention to effect removal of a push rod from an internal combustion engine and installation of the push rod in an internal combustion engine. The purpose and function of the tool of the invention is to engage an internal combustion engine rocker arm in a manner which will effect pivoting of the rocker arm about its pivot axis in a manner which compresses the spring that engages the rocker arm on one side of the rocker arm pivot axis so as to permit removal of a push rod associated with and engaged with the opposite side or end of the rocker arm.  
         [0019]     That is, a typical internal combustion engine will include a plurality of rocker arms each mounted on a transverse pivot axis or shaft so as to have one end projecting outwardly from that pivot axis to engage a push rod associated with the operation of a cam of the internal combustion engine. The opposite end of the rocker arm is biased by a spiral compression spring mounted in a recess or counterbore in the cylinder head of the engine. The spring engages the rocker arm biasing it about its pivot axis into engagement with the push rod. An object of the invention is to provide a tool which will pivot the rocker arm against the compression force of the spring mounted on the cylinder head in a manner which enables the rocker arm to be moved independently away from engagement with the push rod so as to enable access and removal of the push rod as a result of the displacement of the rocker arm out of engagement with the push rod.  FIGS. 1 and 2  therefore depict the tool itself and  FIGS. 3-6  depict the utilization of the tool of  FIGS. 1 and 2 .  
         [0020]     Referring therefore to  FIGS. 1 and 2 , the tool is comprised of a first elongate frame member  10  and a second generally mirror image elongate frame member  12 . The frame member  12  is comprised of a longitudinal run  16  and the frame member  10  is comprised of a longitudinal run  14 . The longitudinal runs  14  and  16  are joined together by welding or fasteners or the like and include a distal or hand grip end  18  with a molded hand grip  20  attached thereto. The frame members  10  and  12  extend in the range of 8 to 20 inches in longitudinal length along the longitudinal axis  22 .  
         [0021]     Frame members  10  and  12  further include, respectively, spaced rocker arm ends or runs  24  and  26  to engage the rocker arm. The arm ends  24 ,  26  are generally parallel and are spaced from one another approximately in the range of ¾ to 1 inch. A first, distal end plate  28  extends transverse to the axis  22  and connects the distal ends of the frame member arm engaging ends  24  and  26 . The first end plate  28  is affixed to the ends  24  and  26  at the top side or top planar side of the ends  24  and  26 .  
         [0022]     Spaced inwardly from the end plate  28  is a second, transverse internal plate  30  attached to the lower sides of the ends  24 ,  26  of frame members  10  and  12 . Plate  30  extends between runs  24 ,  26  and includes a notch  32  axially aligned with axis  22  and opening toward the first end plate  30 .  
         [0023]     The frame members  10 ,  12  are typically made from steel sheet or bands as depicted. The top surface detent notches  36  are sized and positioned so as to provide a space into which parts of the engine may fit when the frame members  10  and  12  are rotated as depicted. Thus, the notches  36  provide a means to avoid interference of the tool with component parts of the engine which are desirably maintained on the engine block and thus not required to be removed during the repair operation utilizing the tool of the invention. Each of the frame members  10  and  12  further includes a top surface detent notch  36  generally aligned with and extending inwardly from the notched plate  30 . It is to be noted that the end plate  28  and the notched plate  30  are not coplanar but rather are affixed to the frame members  10  and  12  on the opposite or the top and bottom sides, respectively, thereof and generally extend along parallel planes defined by the top side and bottom side surfaces of the frame members  10  and  12 .  
         [0024]     As depicted in the Figures, an optional feature of the invention is the inclusion of a socket opening  80  formed in the frame members  10  and  12  and more particularly formed in the portion of the frame members which are joined together. The socket opening  80  is typically a square passage or polygonal shaped which enable the insertion of a socket wrench or other device so as to provide a longer lever arm or mechanical advantage during use of the tool.  FIG. 6  illustrates this feature wherein the socket wrench arm  82  is positioned to engage a socket into the socket opening  80 .  
         [0025]     Referring to  FIGS. 3-6  there is depicted the manner of use of the tool depicted in  FIGS. 1 and 2 . An engine or cylinder head  40  includes a valve spring  42  in a recessed pocket  44  engaged with a rocker arm  46  and, more particularly, the outer end  48  of the rocker arm  46 . The rocker arm  46  is pivotal about a shaft  50  mounted on appropriate bearings that are supported on a rocker arm support element  52  extending from the cylinder head  40 . The rocker arm  46  pivots about a transverse axis  54  of shaft  50  and includes an outer push rod engaging end  56  for engagement with a push rod  58 .  
         [0026]     An object of the invention is to engage the tool depicted in  FIGS. 1 and 2  with the rocker arm  46  so as to compress the spring  42  and thereby disengage the rocker arm  46  from the push rod  58 . This is accomplished by placing the end plate  28  in contact with the outer end  48  of the rocker arm  46  and simultaneously placing the notched plate  30  against the opposite end  56  of the rocker arm  46 . The tool is then manually manipulated by movement in the direction of the arrow in  FIG. 3  to compress the spring  42  and thereby disengage the rocker arm  46  from the push rod  58  as depicted in  FIG. 4 . This is also depicted in  FIGS. 5 and 6 . The push rod  58  may then be removed from the engine and reinstalled or otherwise repairs may be effected to the engine.  
         [0027]     While there have been set forth a preferred embodiment of the invention, it is to be understood that the invention is limited only by the following claims and equivalents.