A valve train with cam switching used for intermittent control of a
four-cycle internal combustion engine. The valve train comprises a
splined shaft, one cam block per cylinder, and a housing-mounted actuator
pin. On each end of the cam block is a cylindrical end piece and a
mirror-symmetric displacing groove. A housing-mounting actuator pin
inserts radially into each displacing groove. The cam block reciprocates
axially through the cooperation of the actuator pins and the displacing
grooves when the engine is running. Low wear of the valve train and a
high switching speed are achieved due to the fact that the displacing
grooves possess an accelerating flank with an impact ramp that results in
a constant, low initial axial speed of the cam block and a feeble impact
force of the actuator pins.