Patent ID: 7628128

Claim:
A variable valve control apparatus, comprising: a valve; an oscillating arm, one end of which engages with said valve for actuating said valve between a closed position and an open position; a pivot lever which is pivotably mounted on said oscillating arm via a swivel joint that is situated on said pivot lever, said pivot lever having first and second arms which extend outwardly from said swivel joint; a cam mounted on a cam shaft and having a camming surface; a first roller which is rotatably mounted on said first arm of said pivot lever, and engages said camming surface of said cam; a second roller which is rotatably mounted on said second arm of said pivot lever; and an arcuate sliding block which is disposed within a housing, and which has a contact surface that engages said second roller of said pivot lever; wherein, said contact surface comprises a first region which has an arcuate contour, and which has a radius that is centered on a pivot axis of said swivel joint when said valve is in said closed position, and a second region which adjoins said first region, and which has a curved spur that extends inwardly toward said swivel joint; and said sliding block is slidable along an arcuate path within said housing, about a center of rotation that coincides with a pivot axis of said swivel joint when said valve is in said closed position; said sliding block is slidable between a first position in which said second roller engages said first region of said contact surface, and a second position in which said second roller engages said second region of said contact surface; when said sliding block is in said first position, camming movement of said first roller by said camming surface of said cam causes said pivot lever to pivot about said swivel joint, which remains stationary, so that said valve remains closed; and when said sliding block is in said second position, engagement of said second roller with said spur causes said camming movement of said first roller to move said swivel joint downward, and said oscillating arm actuates said valve to an open position.