Patent GB-911159-A (GB)
Title: Web marking apparatus
IPC: B41K3/14
Filed: 1960-09-19
Abstract: 911,159. Rotary printing machines. GOTTSCHO Inc., ADOLPH. Sept. 19, 1960 [Dot. 21, 1959], No. 32094/60. Class 100 (2). An apparatus for applying repeated markings to successive sections of a continuous web with each marking extending along a predetermined length of the related web section, which apparatus is of the type comprising a back-up roll around which the web is fed, a marking roll having marking means on the periphery thereof and being rotatably supported for rolling and marking contact of the marking means with the web on the back-up roll, drive means for rotating the marking roll in accordance with the feeding movement of the web, and latch means operative to hold the marking roll against rotation at an initial position and being momentarily released in synchronism with the feeding movement of the web to permit rotation of the marking roll through a single revolution whereupon the latch means is again operative to hold the marking roll against rotation beyond the initial position, is characterized in that the circumference of the marking roll is slightly smaller than the length of each web section to be marked, and in that the drive means for the marking roll has slip means interposed therein which slips during the final increment of movement of the web through the length of a web section following the return of the marking roll to its initial position. The marking apparatus 16 shown, which is associated with an intermittently operating bread wrapper 10 which receives a continuous marked web W and cuts it into successive lengths by a suitable knife arrangement, is mounted on a stand 18 above a supply roll 26 of the web from which the web travels upwardly over a tensioning roll 28, an idler roll 34 and a back-up roll 38 of the apparatus 16 which supports the web during the application of repeated markings to the latter. The marked web then passes under a vertically adjustable registering roll 40 and over an idler roll 46 before passing to the machine 10. Adjustment of the roll 40 is effected to vary the longitudinal registration of the repeated markings with respect to the operation of the wrapping machine knife. The marking apparatus 16 embodies a carriage assembly 48 mounted at the top of stand 18 and a marking head 50 which is supported by carriage 48. The back-up roll 38 is supported in angularly adjusted arms 62 the turning of a screw 84 serving to angularly displace the related arm 62 which is secured in position by a screw 80. The marking head is mounted on spaced bars 86 which supports a plate 90 projecting at right-angles thereto and carrying a slidable bearing block 92. The latter supports a bearing mounted rotatable sleeve 104 parallel to the roll 38 and driven through a shaft 106 by a transmission including a spur gear 112 meshing with a spur gear 114 of a slip clutch assembly 116 having a shaft 118. This assembly is such that whenever web W is intermittently fed into machine 10 by draw rolls 12, 14, a chain and sprocket transmission 134, 136, 138 effects rotation of the shaft 118 and the assembly 116 tends to cause corresponding rotation of gears 114 and 112 at speeds that vary with the rotational speed of roll 14. In order to effect accurate registration of the repeated markings applied to the web with respect to the successive cut-off lengths of the latter, rotation of shaft 106 is only permitted during a predetermined portion of the operating cycle of the machine 10. Such control is effected by a clutch assembly that includes a stop-pin 146 projecting from the gear 112. A longitudinally slidable latch bar 148 has a nose 156 normally projecting into the circular path of movement of pin 146 through the agency of a tension spring 158. Latch bar retraction is effected by actuation of a solenoid 166 having an armature 168 which rocks a bell-crank 174 to withdraw the nose 156 against the spring 158. A rotatable timing shaft on the machine 10 operates the solenoid control switch such that it is momentarily energized at the start of the web feeding movement during end operating cycle of the machine 10 in order to release bar 148 from pin 146 when web feed commences whereupon gear 112 is rotated and the bar returns to its normal nose projecting position for halting gear rotation at the completion of a single revolution. The marking head 50 has a base-plate 200 slidable on the bars 86 with side plates 196, 198 of the head projecting forwardly over roll 38. The head is displaceable along the bars 86 by an adjustment screw 210 rotatable by a hand wheel 212 and extending threadedly through a block 214 projecting downwardly from the plate 200. The head further includes a marking roll 216 rotatably mounted between side plates 196, 198 and positioned above the roll 38 so as to apply repeated markings to the web W as it passes over the roll 38. The roll 216, which is mounted on bearing slides 226 such that it may be readily removed with its supporting bearings from the frame of the head, has a circumference which is less than the nominal cut-off length for which the machine is adjusted by an amount, for example, one-quarter inch, which is greater than the maximum negative error in the actual cut-off length, i.e. the amount by which the actual length of the cut section and the length of web fed by the draw rolls during an operating cycle may be less than the nominal cut-off length. With this relationship between the circumference of the roll 216 and the nominal cut-off length when the drive shaft 106, which is coupled to shaft 222 of the roll 216 by a readily-releasable coupling sleeve 240, rotates the roll 216 at a surface speed equal to the web feed speed, the bar nose 156 engages the pin 146 to stop the roll 216 just before the web feed termination and the clutch assembly slips during the final increment of movement of the web. The marking element carried by the roll 216 may be in the form of a flexible metal sheet wrapped therearound in such manner that the said final increment of web movement may occur free of contact with the marking element. Any change in the cut-off length for which the machine 10 is adjusted requires replacement of the marking roll 216 by another such roll having a circumference corresponding to the new cutoff length. Gear 112 will also have to be changed. Consequential adjustment of the support arms 62 carrying the roll 38 will be necessary. Adjustment of pressure between the two rolls is effected by mounting the bearings of the roll 38 in eccentric supports. The arrangement permitting removal of gear 112 upon mere loosening of a set-screw 121, Fig. 13, also permits rotational adjustment of pin 146 carried by the gear 112 with respect to shaft 106 upon loosening of a set-screw 113, whereupon gear 112 may be turned relative to its hub for adjusting the rotational position of shaft 106, and hence of the marking roll 216, with respect to the operating cycle of the machine 10. The marking element of the head is inked by an inking roll 246 rotatably mounted in an ink reservoir 252 which is pivotally supported by an axle 254. Tilting of the reservoir is effected by actuation of two cams 262 which are mounted above the marking head and move vertical spring-loaded rods 260 attached to the reservoir through hookengaged pins 256. Clockwise turning of the cams from the position of Fig. 6 tilts the reservoir downwardly at the back to an inoperative position, where roll 246 is spaced from a metering roll 272. The latter roller is eccentrically mounted in the marking head frame, the eccentric bearing housings 278 thereof having handles 280 by which the parallelism of the rotatiohal axes of roll 272 and roll 216, as well as the distance therebetween, are manually adjusted. The two rolls are both driven from the marking roll 216 by a gear transmission having components which permit the necessary adjustment when the marking roll is replaced upon a change in the cut-off length. Since rolls 246 and 272 are driven from roll 216 it is apparent that when the latter is held against rotation rolls 246 and 272 are also at rest to interrupt the supplying of ink to the marking element. During any protracted shut-down of the apparatus, reservoir cams 262 may be operated to tilt the reservoir and thereby separate the ink supplying roll 246 from the metering roll 272 to avoid permanent indentation of the surfaces of such rolls due to the pressure of the contact therebetween.