Patent GB-189901671-A (GB)
Title: Improvements in Tympan-shifting Mechanism for Printing Machines.
Inventor: NEWTON HENRY EDWARD
Filed: 1899-01-24
Granted: 1899-03-25
Abstract: 1671. Newton, H. E., [Hoe, R.]. Jan. 24. Set-off, preventing ; cylinder machines with plane printing-surfaces; rotary machines. - Relates to means for shifting, after each impression, a set-off web or tympan over the impression surface of the second cylinder of a perfecting-machine, such as a two-revolution cylinder machine. The set-off web or tympan is moved the length of a sheet or forme after each impression, so as to present a fresh portion to receive the sheet being printed. Fig. 1 shows an end view, and Fig. 3 a section of an impression cylinder with one form of the tympan-shifting mechanism applied to it. The tympan or set-off web W passes over the impression surface from one of the rollers T, R to the other, and is guided by rollers 50, 51. As shown in the Figures, the roller R is the winding-off roller and T is the winding-on roller, but when the web is exhausted from the roller R the movement is reversed and the web wound back on to the roller R. The rollers T and R are each driven, for winding on the web W, through a special form of friction clutch, by a pinion 60, 61 gearing with a fixed gearwheel 62. Springs 74 tend to clutch the rollers T, R to the wheels 60, 61, the clutches acting with such force that they operate the winding-roller to roll up the web released by the winding-off mechanism, and slip when the latter stops. Pivoted on the shaft 150' of the cylinder is a frame O, carrying two rollers K, L, and balanced by a weight 59. This frame is pressed in opposite directions by two pairs of slides 82, 84 operated by springs 80, 86. The slides carry rollers 2, 4, which may be operated by cams D to remove the pressure of the slides at one side of the frame O and permit the opposite slides (in the position shown the slides 82) to press the roller L against the roll of web V on the winding-off roller R. The cams D also operate arms 12, 13 and tappets 76 which engage the projections 75 to unclutch one of the friction clutches, so as to free the winding- off roller from its driving-wheel 60, 61. The rollers K, L are driven to wind off the set-off web W by sprocket gears and a chain 32 driven by a sprocket-wheel 33, on the shaft 36 of which is a pinion 37 gearing with the wheel 62. The pinion 37 is clutched to its shaft 36 at the required times to wind off the length of web W by a friction clutch, operated by a cam 52 on the fixed wheel 62, which cam is caused to connect the clutch at every second revolution of the cylinder, by the action of a switch piece 53 operated by a cam. The length of the cam 52 is preferably adjustable for varying the length of tympan web W fed off at each operation of the cam. The reversal of the feed is effected by turning the cams D so that they release the rollers 2 and arm 12, and operate the rollers 4 and arm 13, thus throwing the roller K against the web wound on the roller T, and unclutching the roller T from its driving-pinion 60. This reversal may be effected automatically by a compound ratchet and cam gear, operated from the cylinder shaft, and so arranged that the cam thereon presses a sliding bolt into the path of cams or projections on segmental arms pivoted on the cylinder and geared to the shaft 19 of the cams D. The reversal takes place after the required number of revolutions of the cylinder, according to arrangement of the compound ratchet gear. The clutch described for driving the shaft 36 consists of a bent spring, fixed to rotate with the shaft, which expands into engagement with a flanged casing 40 rotating with the pinion 37. The spring is pressed inwardly to disengage the clutch by projections on a band 39 connected at its ends to arms pivoted at 45, operated by a spring 47 and an arm 48 co-operating with the cam 52. The form of clutch described for driving the rollers R and T consists of a flange casing M rotating with the pinion 60 or 61, inside which are movable segments mounted to rotate with the shaft of the roller. These segments are pressed out radially into engagement with the casing M by means of a cam and arms pivoted on the disc 70 operated by the spring 74 and tappets 76. Fig. 25 shows, in sectional elevation, a cylinder having a modified arrangement of mechanism for shifting the set-off web. The set-off web W passes from one roll R to the other T over the impression surface E and between pairs of feeding- rollers 124, 125 and 126, 127. The rollers Rand T are each provided at one end with a special form of friction clutch through which the rollers are geared to a fixed spur-wheel concentric with the shaft 199. The roller which is to act as the winding-up roller (T in the Figure) is clutched to its driving-pinion, and the other roller Run. clutched, by a cam on a shaft 190. On the shaft 190 is also a cam 192 operating a spring lever 194 to apply a brake shoe 171, on a lever 191, to the paying-off roller R, and remove the brake shoe 172 from the winding-roller T. The feeding-rollers 124, 125 and 126, 127 are driven by a wheel 160 loose on a hub of the cylinder shaft 199. The wheel 160 is driven from a shaft 164 driven, at the required intervals to feed the set-off web, through a friction clutch, from the fixed wheel which drives the rollers R and T. The clutch on the shaft 164 is generally similar to those of the rollers R, T, and its lever is operated by a cam to revolve the shaft at the required intervals and for the required length of feed. A brake is applied to stop the shaft when the clutch is disengaged. The shaft 164 is geared to a wheel 165 by the wheel 166, and these wheels 165, 166 drive, through clutches, wheels 162 and 163 respectively. The wheels 162 and 163 are both geared to the wheel 160 by an intermediate 161. Only one of the wheels 162, 163 is clutched to its driving-wheel 165, 166 at one time, and, as the wheels 162, 163 drive the wheel 160 in opposite directions, the direction of feed is reversed by reversing the clutches. The clutches are operated by arms on a shaft operated by a cam on the shaft 190. The shaft 190 is operated to reverse the feed by a tumbler cam on one of its ends, operated by a sliding pin actuated at the required times by a compound ratchet and cam gear. The form of clutch described for driving the shaft 164 and rollers R and T comprises a flanged casing and expanding or radially-movable segments. The segments are expanded by a split ring between which and the segments are antifriction rollers. The split ring is expanded by a roller on a disc pivoted concentrically with the shaft. Fig. 46 shows a means for reversing the direction of feed of the set-off web W, controlled by the quantity of web remaining on the winding-off roller. The web may be fed as described above with reference to Fig. 25. Pivoted at 299<1> on a bracket carried by the cylinder shaft 299 are two levers 200, 201 each having a roller 203 for engaging the roll of web on one of the rollers T, R. Springs 202 tend to press the rollers 203 against their respective web rolls, and the roller 203 is held away from the winding-on roller (in the Figure, T) by a cam 206 on the reversing-shaft 290. When the web is nearly exhausted from the roller R, an arm 231 of the lever 201 engages a lever 230 which moves a spring pawl 213 to release a rod 211 movable longitudinally in the cylinder shaft 299. The rod 211 is moved by a spring, and operates to move the sliding pin which engages the tumbler cam on the reversing-shaft 290. When the shaft 290 is moved, the cam 206 moves the lever 201 out of operation, and puts the lever 200 into operation with its roller 203 against the roller T.