Patent GB-327804-A (GB)
Title: Improvements in or relating to machines for transferring or offset printing of designs on to cylindrical surfaces
IPC: B41F3/34
Filed: 1928-10-24
Abstract: 327,804. Pictorial Machinery, Ltd., Linzell, L., and Phythian, T. E Oct. 24, 1928. Cylinder offset machines; bedreciprocating apparatus; tripping-arrangements.-Relates to machines of the type described in Specification 30002/10 for transferring or offset printing of designs on to cylindrical surfaces wherein a design on a flat surface is transferred to a cylindrical surface to be exactly covered by the design through the medium of a resilient curved surface, and is particularly applicable for transferring a design to a roller to be subsequently etched to produce a printing-surface for use in continuous web-printing. The machine comprises a reciprocating bed and is provided with mechanism to prevent rotation of the resilient surface during the return movement of the bed, an electric motor automatically reversible at the limits of movement of the bed, and means for mounting the cylindrical member, for pressing it into contact with the'resilient surface, and for independently indicating and adjusting the pressure between the two ends of the cylindrical member and resilient surface. The machine comprises a reciprocating bed 14 supported on rollers 17, 18, 32, arranged on fixed axes in the frame of the machine, and provided with a rack 36 engaged by a gear wheel 16 carried by a shaft 15 driven by reduction gearing from an electric motor 24, Figs. 1 and 3. The sets of rollers 17, 31 and 18, 32 are arranged in line in the direction of travel of the bed, and the rollers 17, 18 are of larger diameter than the rollers 31, 32 and are situated directly below the cylinder 54 supporting the resilient surface 55. The bed 14 carries a vertically-adjustable platform supporting a rotatable table to which the designcarrying plate is secured. The cylinder 54 is carried by a shaft 53 journaled above the frame of the machine and carries a mutilated gear-wheel 68, Figs. 5 and 7, meshing with a rack 69 secured to the bed 14, the mutilated part of the wheel coming adjacent to the rack at the limits of movement of the bed. The gear-wheel is provided at its mutilated portion, with a plate 75 carrying a tooth 77 adapted to be engaged by a spring-pressed detent 80 pivoted to the frame of the machine and normally held in inoperative position by a catch 83. At the end of the operative movement of the bed, the catch is released by the face 90, Fig. 8, of a trip-member 88 secured to the rack 69, and the tooth 77 is positioned by the face 91 of the member 88 in order to be engaged by the detent 80. During the return movement of the bed, the wheel is, therefore, prevented from rotation. When the bed reaches its limit of movement in the oppositedirection, the detent is withdrawn from engagement of the, tooth 77 by a trip member 87, Fig. 9, pivoted to the rack 69, and provided with a. notch 95 to engage the tooth 77. When the bed, commences its operative movement, the detent 87 carries the gear-wheel 68 round until its unmutilated teeth re-engage with the rack. When the bed reaches the end of its operative movement, a stop 208 thereon engaged a switch 37 which serves to reverse the motor 24 and return the bed to its original position, while, at the end of the return movement, a stop 210 on the bed opens a stop switch 38. The motor is also under the control of manually-operated " forward," " reverse," and " stop '' switches. The cylindrical surface 63, Fig. 5, to which the design is to be transferred is carried by a shaft 62 mounted in split bearings adjustable by means of screws 260 in brackets 60 to enable the pressure between the surface 63 and resilient surface to be regulated, the brackets being journaled on a rock-shaft 58 carried in arms 56 above the framework. The brackets are provided with projecting lugs 103 arranged opposite to corresponding lugs 102 on bushes secured to the shaft 58 and a spring 106 is mounted between each pair of lugs, the springs tending to force the surfaces 55, 63 into contact. The angular movement of the brackets is limited by nuts 108. The pressure between the surfaces is indicated on indicators 129 each connected to a lever 127 pivoted to the lug 103 and controlled by a link 130 connected to the lug 102. A lever 112 is secured to the shaft 58, and is provided at its, other end with a roller engaging a cam 64 of known construction mounted on a shaft 65 and continuously driven by the gear-wheel 68. The cam is adjustable so as to hold the cylinder 63 in contact with the surface 55 for the correct period. To prevent the surface 63 from being brought into contact with the surface 55 during adjustment of the machine, the lever 112 is provided with an eccentric 123.. In order to enable the shaft 62 to be driven at slightly increased or decreased speeds for the purpose of avoiding a gap or overlap between the ends of the design when transferred to the surface 63, a rack 72, Fig. 3, the pitch of the teeth of which is slightly less than that of the teeth of the rack 69, is mounted for longitudinal movement relatively to the bed as described in the prior Specification referred to. The rack mesheswith a gear-wheel 71 loosely mounted on the shaft 53 and engaging a gear-wheel 70 on the shaft 62. The rack is moved relatively to the bed by means of a gear-wheel 334 actuated by a rack 332 on a pivoted slideway 133 wherein engages a roller 132 on the bed. The slideway is actuated by means of a screw-threaded spindle 135, provided with a graduated handle 340 working in a block pivoted on the frame of the machine and engaging a block pivoted to the slideway. Movement of the lever 112 by the cam 64 is insufficient to disengage the gear-wheels 70, 71.