Rotary printing press

A rotary printing press for single sheets of the type comprising a rotary printing cylinder, means for driving the printing cylinder at a constant velocity, a feeder table onto which the sheets are fed partly overlapping, means on the feeder table for setting the sheets in register frontally and laterally, a rotary transfer drum having a diameter larger than the diameter of said cylinder, means driving the transfer drum at an angular velocity which varies periodically with a period equal to the time taken by the printing cylinder to make one complete revolution, oscillating transfer means having gripping means for transferring the sheets from the feeder table to the transfer drum and means for transferring the sheets from the transfer drum to said printing cylinder, wherein the improvement comprises elliptical gear means operatively disposed intermediate said printing cylinder and said transfer drum, said elliptical gear means being sized to impart to the transfer drum a peripheral velocity which varies from a minimum value substantially equal to the constant peripheral velocity of the printing cylinder to a maximum velocity which is higher than said minimum value and higher than the peripheral velocity of the printing cylinder, cam means mounted on the axis of said printing cylinder for driving said oscillating transfer means, said cam means being rotationally oriented relative to the printing cylinder such that the transfer means is moved from a stop position adjacent said feeder table, at which time said gripper means picks up a sheet from said feeder table, to a velocity greater than the peripheral velocity of said printing cylinder adjacent to said transfer drum prior to the transfer drum reaching its maximum velocity and additional gripping means on said transfer drum for receiving a sheet from said oscillating transfer means when the velocities of said transfer drum and said oscillating transfer means are equal and means to render said means for transferring the sheets from said transfer drum to said printing cylinder operative when the peripheral velocity of said transfer drum is equal to the peripheral velocity of said printing cylinder.