Abstract: An angular position of a lever with which a rocker arm contacts to define a fulcrum therebetween is varied by rotation of a cam which is installed in a manner to be rotatable relative to its cam shaft and drivingly connected through a spring to the cam shaft or to an output shaft of a driving system.

Abstract: The present invention features a variable valve timing arrangement having a zero valve clearance maintaining device which takes the form of either a springy finger-like extension provided on a valve timing control lever, which extension biases a rocker arm which operates the valve, against the valve stem until the rocker arm has been cammed to pivot by a predetermined amount; or an eccentric bush on which the control lever is mounted and a telescopic hydraulic cylinder arrangement which rotates the bush to press the lever against the rocker arm with a predetermined force adequate for maintain a zero valve clearance.

Abstract: The present invention features a valve train for inducing reciprocative motion in a valve which includes a lever pivotally mounted at one end thereof, a rocker arm which engages the lever to define a fulcrum point therebetween, and which engages a valve at one end thereof, a first cam which engages the other end of the rocker arm, a second cam which engages the top of the lever and a mechanism which guidingly interconnects the rocker arm, at a point intermediate of the ends thereof, with the lever for preventing relative slip therebetween and for ensuring that a cam following portion of the rocker arm smoothly follows the first cam.

Abstract: A reaction member located above an angled rocker arm induces the latter to pivot once a telescopically extendible hydraulic tappet, under the influence of a cam, has lifted the rocker arm sufficiently to engage an apex thereof against the reaction member. The tappet includes a piston which defines therein a variable volume chamber into which hydraulic fluid may be readily introduced via a solenoid control valve, but only slowly discharged. The degree of extension of the tappet controls the valve lift induced by the rocker arm.

Abstract: A variable valve timing system has a lever pivoted at one end on a piston reciprocally disposed in a cylinder and the other end in engagement with a poppet valve. A first cam cooperates with a second bell crank lever like cam which is eccentrically mounted on a rotatable shaft. Rotation of this shaft moves the second cam toward or away from the engine proper to vary the movement of the lever with which the second cam cooperates. The piston is biased out of the cylinder by a spring and maintained in position by hydraulic fluid introduced into the cylinder through a one way flow arrangement.