Deactivating rocker arm / mechanical lash adjustment system

Abstract

A deactivating rocker arm mechanical adjustment system for internal combustion engines is provided wherein a lash adjustment screw which has eccentric cam and a feature by which the screw can be rotated using a tool. The adjustment screw is installed a valve actuation section of a split rocker arm wherein the cam end of the adjustment screw engages a feature of the cam follower section of the split rocker arm. When the lash adjustment screw is rotated, the design of the cam is such that the angular orientation of the valve actuation and cam follower sections is varied and in turn varies the distance or lash between the cam follower section latch pin and the receiving latch pin hole in the valve actuation section. The lash adjustment screw is rotated until a previously specified lash is obtained and then a jam nut is tightened to prevent rotation of the lash adjustment screw. Valvetrain component design may be altered that other than threaded means may be used to control the rotational orientation of the adjustment cam. An additional feature of the invention is that in the preferred embodiment, the lash adjustment screw provides a valve actuation section feature upon which a lost motion spring is mounted.

1 . In a rocker arm comprising a split rocker arm having a first section and a second section, the improvement comprises an adjustment system including a cam positioned between said sections, said cam which, when rotated, changes the angular orientation of said first section and said second section of said split rocker arm, thereby controlling the lateral clearance between the latch pin in said first section and a receiving latch pin hole in said second section to permit free movement of the latch pin which, when engaged opens an engine valve in response to the valvetrain camshaft, and which, when disengaged, permits one section of the rocker arm to rotate in response to the valvetrain camshaft without opening the engine valve. 
   
   
       2 . The rocker arm/mechanical adjustment system of  claim 1  which includes a valve actuator section and a cam follower section. 
   
   
       3 . The rocker arm/mechanical adjustment system of  claim 2  wherein the cam follower section includes the adjustment system. 
   
   
       4 . The rocker arm/mechanical adjustment system of  claim 2  wherein the valve follower section includes the adjustment system. 
   
   
       5 . The rocker arm/mechanical adjustment system of  claims 3  and  4  wherein the adjustment system includes a cam at one end of a threaded pin or screw which includes a wrenching feature and a locking feature. 
   
   
       6 . The rocker arm/mechanical adjustment system of  claims 3  and  4  wherein the adjustment system includes a cam at one end of a pin or shaft which includes a wrenching feature and is locked by bonding, welding, or mechanical means. 
   
   
       7 . The rocker arm/mechanical adjustment system of  claims 3  and  4  wherein the adjustment system includes a cam which includes a wrenching feature and which is shouldered within a recess or other feature and is locked by bonding, welding, or mechanical means. 
   
   
       8 . The rocker arm/mechanical adjustment system of  claim 2  wherein the cam follower section includes a tubular cam follower body and a deactivation section. 
   
   
       9 . The rocker arm/mechanical adjustment system of  claim 2  wherein the latch pin is a threaded pin. 
   
   
       10 . The rocker arm/mechanical adjustment system of  claim 2  wherein the valve actuator section includes a tubular body and an arm portion attached to said tubular body. 
   
   
       11 . The rocker arm/mechanical adjustment system of  claim 2  including a lost motion spring that extends less than 360° around the valve actuator section.