Abstract: In an arrangement for operating valves of an internal combustion engine by means of at least two operating members for opening and closing each valve and a camshaft with cams having base portions and camming portions for operating the operating members wherein the operating members for a valve are disposed in side-by-side relation and have guide bores which are aligned when the operating members are disposed on the base portions of the cams and a coupling pin is movable in the guide bores and couples the adjacent operating arms when disposed so as to extend thereacross for movement of said adjacent operating members in unison, the coupling pin is barrel-shaped wife tapered end sections and a center section of a larger diameter which, with the guide bores of the adjacent operating members, forms a cylindrical fit with a clearance of 1-60 .mu.m.

Abstract: The invention relates to a device for angularly adjusting an internal combustion engine camshaft in relation to a crankshaft and comprises an adjusting bushing connected to the camshaft, with an input sleeve surrounding said bushing, and with an actuator displaceably arranged there between. An input sleeve, the actuator, and the adjusting bushing are each provided with helical gear teeth to translate axial shifting of the actuator into relative rotation between the camshaft and crankshaft. In order to prevent rattling noises in the gear teeth that are caused by changing moments in the drive of the camshaft, the actuator is guided in stop-free fashion. A stop, which is effective between the input sleeve and camshaft, limits the angular adjustment so that the actuator is stressed between the input sleeve and camshaft to avoid backlash during rattling.