Harmonic drive register adjustment device for a printing press

Claim 1

A printing press comprising, first and second cylinders defining a printing nip and having a first position in which said cylinders are cooperable to print on at least one side of material advanced through the nip, said first and second cylinders comprising a blanket cylinder and another cylinder, a plate cylinder cooperable with the blanket cylinder for transferring an image to the blanket cylinder, throw-off means for bodily relatively moving said first cylinder and said second cylinder away from said first position to a second position and from said second position toward each other to said first position, means for drivingly interconnecting said first and second cylinders when in their first and second positions, said means comprising, first and second gear means, means for drivingly connecting said first gear means to said first cylinder, means for drivingly connecting said second gear means to said second cylinder, said first and second gear means having gear teeth which are engaged to provide a drive therebetween when the cylinders are in their first and second positions, third gear means having gear teeth in a meshing driving relation with gear teeth of said first gear means when said first and second cylinders are in both said first and second positions, means drivingly connecting said third gear means with said plate cylinder, the number of gear teeth on said first gear means meshing with the gear teeth of said third gear means being less than that required to rotate said plate cylinder at the surface speed of said blanket cylinder, said means drivingly connecting said third gear means with said plate cylinder comprising a differential harmonic drive unit for providing rotation of said plate cylinder relative to said third gear means, said differential harmonic drive unit comprising, an input member drivingly connected with said third gear means, said input member having a predetermined number of internal gear teeth thereon, a deformable output member drivingly connected to said plate cylinder and having a number of external gear teeth thereon less than the predetermined number of internal gear teeth on said input member and positioned such that said external gear teeth of said output member are fully meshing along a portion of the periphery thereof with said internal gear teeth, the number of said internal gear teeth and said external gear teeth being such as to compensate for the reduced number of gear teeth on said first gear means so that said plate cylinder is rotated at the surface speed of said blanket cylinder, a wave generator member movable relative to said output member to deform said output member such that the portion of said external gear teeth thereon meshing with a portion of said internal gear teeth on said input member varies to thereby vary the circumferential position of said plate cylinder relative to said third gear means, a motor means drivingly connected to said wave generator member to effect rotation of said wave generator member upon actuation thereof, said first gear means comprising a first pair of gears and said second gear means comprises a second pair of gears, said first pair of gears comprising first and second gears, said second pair of gears comprising fourth and fifth gears, said first and fourth gears and said second and fifth gears respectively having an equal number of teeth which have a meshing relationship when said first and second cylinders are in their printing position as well as when said cylinders are in their second position, said first gear having gear teeth in a meshing relationship with said third gear means, and said first and fourth gears having a smaller pitch diameter than said second and fifth gears, and the number of gear teeth on said first gear meshing with said third gear means compensating for the difference in the number of gear teeth between said internal and external gear teeth so that said blanket and plate cylinders are rotated at the same surface speed.