Patent GB-416665-A (GB)
Title: Improvements in and relating to platen printing presses
IPC: B41F1/28
Filed: 1933-02-14
Abstract: 416,665. Platen printing-machines. SCHNELLPRESSENFABRIK AKT.-GES., HEIDELBERG, Heidelberg, Germany. Feb. 14, 1933, No. 4513. Convention date, Feb. 16, 1932. [Classes 100 (i) and 100 (ii).] Feeding sheets.-An apparatus for use on automatic platen printing-presses for adjusting the rising or falling movement of the sheet piles and the tipping movement of the suckers for feeding the sheets, to suit the nature of the paper to be printed upon, is characterized by the feature that the extent of the continuous swinging movements of a control cam member which controls the movement of the suckers, and of a member controlled by a feeler or the like which controls the extent of movement of the pile, are adjustable by means of adjusting- devices having pointers or the like which co-operate with scales corresponding to the respective paper thicknesses, and which do not move relatively to the scales during the said swinging movements. The bed 1 of the machine supports a platform 4 on which is secured a frame 6 in which is slidable, in guides 8, a bar 7 actuated by a lever 9. On the bar 7 is secured a bearing head 12 in which is mounted a suction tube 13 connected by flexible tubing to a pump actuated from the machine. Suckers 15 on the tube 13 are adapted to remove the sheets from the pile p and deliver them to feed and delivery grippers 16 which rotate in a plane parallel to the platen 3 of the machine, as described in Specifications 276,868, [Class 100 (ii)], and 388,943. The suckers 15 are raised from position I into position II in which they deliver the sheet seized by them to the grippers 16, and are then moved into position III to allow the grippers to swing freely below the suckers ; the suckers are then moved downwardly into position I in order to take up a fresh sheet. In order to seize sheets of different materials, such as cardboard or tissue-paper, the suckers are adapted to be tipped. A graduated scale 17 co-operates with a pointer 18 which can be adjusted by the nut-and-screw arrangement 20, 22 to move over the scale, the pointer being situated at one end of a lever 19 pivoted at 23 on one of the guides 8. An arm 24 pivoted along the lever 19 is hinged to a control cam member comprising a cam lever 25 pivoted at 25<1> on the vertically slidable bearing head 12, and provided with a cam groove 25<2> in which engages a roller 26 attached to a lever 27 fixed to the tube 13 bearing the suckers 15. Adjustment of the pointer 18 results in the roller 26 being displaced in the cam groove, and thereby the position of the suckers is altered. The arrangement for determining the upward movement of the feed pile p, and consequently the downward movement of the delivery pile, comprises an eccentric 37 secured to a stud 36 mounted on a lever 33 rotatably pivoted at 23 on the guide 8, the lever 33 being integral with a graduated scale 32. A lever 35 provided with a pointer 34, adapted to move over the scale 32, is also secured to the stud 36, so that when the pointer is adjusted, the eccentric 37 is also adjusted. Also pivoted on the stud 36 is a rod 38, pivoted at its lower end at 40 to one arm of a pivoted lever 39. The other arm of the lever 39 is forked to guide the movements of a pawl 42 on a lever connected to a bell-crank lever 44 pivoted at 45 on the axle of a ratchet wheel 43. The bell-crank lever 44 is actuated through a rod 46 from the machine. Normally the rod 38 is depressed against spring action to hold the pawl 42 clear of the ratchet-wheel 43. Gear-wheels 47, 47', operated by the axle 45 mesh with the racks of the feed and delivery piles so that the former is raised and the latter is lowered. The means for normally depressing the rod 38 comprises a two-armed lever 28, 29 pivoted at 30 on the vertically movable bearing head 12, one arm 29 engaging the eccentric 37, and the other arm 28 carrying a feeler-bar 31 which rests, in the lower position, on the top of the feed pile p. During each downward movement of the head 12 the feeler 31 tests the height of the pile p, and in this position the crank lever 44 carrying the pawl 42 is actuated. According to the adjustment of the eccentric 37 by the lever 35, the arm 29 of the lever carrying the feeler 31 allows the eccentric to rise sooner or later as the height of the pile is reduced. The rod 38 then rises under spring action, and the pawl 42 engages the ratchet-wheel 43 of the feed pile p. The piles of sheets can be initially adjusted by a hand-crank 51, and the ratchet-wheel 43 is provided with a safety or locking-pawl 50. The Specification as open to inspection under Sect. 91, comprises also means for changing over the machine for no-load running, and means for stopping the machine in the event of a sheet not being sucked up, or if the suckers lose the sheet they have sucked up. The movable bar 7 is connected to a casing 55 in which is situated a piston which is normally held inwardly of the casing against the action of a compression spring by air suction. If the suckers 15 miss or lose a sheet then the pressure of the air behind the piston rises and the spring thrusts the piston out of the casing. A lever 51 pivoted on the casing is then moved outwardly by the piston, so that when the casing rises with the suckers, the lever 51 engages a lever 53, which turns a lever 52 out of engagement with a manually-operable coupling-lever 54, whereupon the machine comes to rest. A screw 56 co-operating with a scale regulates the pressure exerted by the compression spring acting on the piston. When it is desired to run the machine on no-load, a member 57 slidable in the casing 55 is moved to the right, so that a latch in its left-hand end prevents the lever 51 from moving outwardly, and so that the suction in the casing 55 and the suckers 15 will be destroyed. This subject-matter does not appear in the Specification as accepted.