Abstract: A machine to facilitate the mounting of flexographic printing plates and for obtaining proofs thereof. The machine includes an impression cylinder supported for rotation on a fixed axis, the impression cylinder making contact with printing plates on a plate cylinder and rotating concurrently therewith to print a proof on the impression cylinder. The plate cylinder is movable from a proofing state in which it makes contact with the impression cylinder to a mounting state in which it is separated therefrom. The flexographic printing plate to be mounted is provided with registration holes and lies on a support tray shiftable from a retracted position displaced from the plate cylinder in its mounting state to an operative position in which its leading edge is parallel to the axis of the plate cylinder and tangentially engages the surface thereof.

Abstract: A mandrel assembly for supporting demountable printing cylinders of different lengths. The assembly includes a tube receivable within the cylinder to be mounted and having journals joined thereto at either end. Encircling each journal are first and second expansible sleeves in side-by-side relation, the first set of sleeves fitting within the end heads of the shorter cylinder when it is mounted on the mandrel assembly, the second set of sleeves fitting within the end heads of the longer cylinder. Below each sleeve on the journal is a relieved zone defining an annular hydraulic chamber. A bore in the journal receives a piston and a tool-operated piston screw, the bore leading into an internal duct having a branch communicating with the hydraulic chamber.

Abstract: A mandrel assembly for a demountable printing cylinder, the assembly including a tube receivable within the cylinder and having journals joined thereto at either end. Encircling each journal is an expansible sleeve, the sleeves fitting within the end heads of the cylinder when it is mounted on the mandrel assembly. Below each sleeve on its journal is a relieved zone defining an annular hydraulic chamber. An axial inlet section which opens into the free end of each journal receives a piston and a tool-operated piston screw, the inlet section leading into an internal duct in axial alignment therewith having a lateral branch communicating with the hydraulic chamber, the duct and chamber being filled with hydraulic fluid. When the piston screw is turned in to advance the piston, the resultant hydraulic pressure is applied through the hydraulic chamber against the inner wall of the sleeve, causing the sleeve to expand and grip the cylinder head, thereby locking the cylinder to the mandrel assembly.

Abstract: A mandrel assembly for a demountable printing cylinder, the assembly including a tube receivable within the cylinder and having journals joined thereto at either end. Encircling each journal is an expansible sleeve, the sleeves fitting within the end heads of the cylinder when it is mounted on the mandrel assembly. Below each sleeve is a relieved journal zone defining an annular hydraulic chamber. A lateral bore in each journal receives a piston and a tool-operated piston screw, the bore leading into an internal duct having branches communicating with the hydraulic chamber. When the piston screw is turned in to advance the piston, the resultant hydraulic pressure is applied through the hydraulic chamber against the inner wall of the sleeve, causing the sleeve to expand and grip the cylinder head thereby locking the cylinder to the mandrel assembly. When the piston screw is turned out, the pressure is released to permit removal of the cylinder.

Abstract: An indexing mechanism in which a workpiece to be machined by a tool is attachable to the end of a rotatable spindle that is driven by the reversible motor of a servomechanism to assume a desired angular position. Mounted on the spindle and rotatable therewith is one gear of a multiple-tooth face gear coupling pair, the second gear of which is axially advanced by a motor along the spindle into and out of meshing engagement with the first gear. The second gear is non-rotatable and acts, when in mesh with the first gear, to prevent rotation of the spindle and thereby lock the angular position of the workpiece.

Abstract: A machine to facilitate the mounting of flexographic printing plates and for obtaining proofs thereof. The machine includes an impression cylinder supported for rotation at a fixed position, the impression cylinder making contact with printing plates on a plate cylinder and rotating concurrently therewith to print a proof secured to the impression cylinder. The plate cylinder is movable in a vertical plane from a proofing state in which it makes contact with the impression cylinder to a mounting state in which it is separated therefrom. A viewer is provided which is operative in the mounting state to show the operator both the plate he is mounting on the plate cylinder and the image reflected from the proof sheet on the impression cylinder.

Abstract: A mounting-proofing machine to facilitate mounting of flexible printing plates on a plate cylinder preparatory to operation in a flexographic printing press and to obtain proofs from these plates, whereby the mounted plates may be checked for color registration and other factors. The machine includes a proofing cylinder cantilevered from and rotatable on the free end of a swing arm adapted to transfer the proofing cylinder from a forward-position proofing state in which it makes contact with the surface of a plate cylinder that has been elevated in a vertical plane intersecting the axes of rotation of both cylinders to effect such engagement, to a rear-position mounting state displaced from this plane. In the mounting state, an optical viewer adapted to observe the surfaces of both cylinders in superposed relation is brought into an operative position which is intersected by the vertical plane.

Abstract: A carrier sleeve for supporting flexible printing plates, the sleeve having a limited circumferential resilience, whereby when subjected to air jets emitted from the apertures in the wall of a printing cylinder, the sleeve is dilated to facilitate the application of the sleeve to the cylinder or its removal therefrom. The sleeve is constituted by three interlaminated layers, each formed by a helix of synthetic plastic tape. Two layers of the sleeve are wound at the same helix angle but are phase displaced relative to each other, whereby the air gap between the convolutions of one layer is bridged by the convolutions of the other, thereby sealing the gap and rendering the sleeve impermeable to air. The remaining layer is wound at an angle opposed to the helix angle of the other two, thereby strengthening and rigidifying the structure of the sleeve.

Abstract: A machine for rolling and curving a metal backed rubber printing plate to conform it to the circumference of a printing cylinder. The machine includes a deflection bar having a longitudinal groove therein which accommodates and partly recesses a forming roller of small diameter. The bar is supported between a pair of clamping blocks which are pivotally mounted, means being provided to simultaneously swing the blocks to a predetermined degree to bow the bar and the roller held thereby. Cooperating with the forming roller is a large diameter driven roller of elastomeric material whose position relative to the forming roller is adjustable to define a nip for receiving the plate to be curved and for pressing the plate against the forming roller as it is conveyed through the nip to impart a desired curvature thereto, the bow formation of the forming roller producing a radius of curvature in the plate which gradually increases as one goes from the center to the outer edge thereof.