Patent GB-398340-A (GB)
Title: Improvements in and relating to mechanism for registering printed webs of paper and the like
IPC: B65H23/188
Filed: 1932-08-19
Abstract: 398,340. Registering webs. AVERY, T. M., 29, Lincoln Avenue, Glen Falls, and UNION BAG & PAPER CORPORATION, 233, Broadway, both in New York, U.S.A. Aug. 19, 1932, No. 23322. [Class 100 (i).] In a photo-electric control for maintaining a travelling web in register with an element of a machine operating thereon by means of control areas of reduced light-reflecting power provided on the web, which suitably modify the light falling upon a photo-electric cell to cause relatively different speeds of operation of the web-advancing means and of the element operating thereon should lack of register occur, means are provided for pivotally supporting the light source and the cell for adjustment angularly of the surface of the web, to focus the light beam on a given area thereof, and to cause reflection therefrom on to the cell. The light projector 62, Fig. 9, and the photo-electric cell tube 60 are mounted on a slide 66 movable on a guide bar 67 fixed to the machine transversely of the web X ; the slide 66 may be adjusted on this bar to bring the light beam into co-operation with different parts of the width of the web by means of a nut 69 and a screw 68 journaled in the front of the machine frame and having an external operating handle. To facilitate focussing, the light projector is pivotally mounted by a horizontal pivot 71 on a vertical pin 72 rotatably and longitudinally adjustable in a clamp 73 carried by the slide 66. The tube 60 is rotatable in the clamp 74a and may also be adjusted longitudinally. The invention is applied to a paper-bag making machine of the kind described in Specification 183,413, [Class 100 (i), Feeding and delivering webs &c.], in which the paper web X is drawn over a guide roll 3 past the photo-electric registering-device, former 7, and slitters 8, by a pair of feed rollers 9, one of which is positively driven and is geared to the other. The usual pinch rolls 10, breaker 11, and folding &c. mechanism 12 are provided, all driven at a constant speed from the shaft 16, which also serves to drive one of the feed-rollers through a variable epicyclic gear comprising a positively driven gear 21 which is fast to a casing 25, Fig. 3, loose on the shaft 14 of the roller 9 and having internal teeth 30 which engage pinions 28 meshing with a gear 27 fast to the shaft 14. The pinions 28 are carried by a member 29 loose on the shaft 14 so that the axes of the pinions may be rotated about the shaft in one direction or the other to increase or decrease the speed transmission between the gear 21 and the feed rollers 9. This is effected through the teeth on the member 29 which mesh with a worm 31, driven in the appropriate direction by a reversible electric motor 36 under the control of the photo-electric device, when the registration marks, and therefore the printed designs on the web, get out of register with the breaker &c. mechanism. The photo-electric device 59, Fig. 10, receives light reflected from the web from a light source 64, and the cell is connected as shown to an amplifying-device 75, in the output circuit of which is included the electromagnet r of a sensitive relay 76. The bias of the grid g of the tube 75 is so adjusted that when the light reflected from the web on to the cell 59 increases, an increased current flows through the electromagnet r and causes this to be strongly energized, whereby its armature r<6> is attracted. The armature r<6> is connected to a switch member r<5> which makes contact with one or other of two contacts r<1> r<2> ; when the armature is attracted, contact r<2> is broken and r<1> is made, thus breaking the circuit of a second electromagnet u, the armature w of which otherwise completes the circuit of the two terminals 88, 89 which are included in that of the motor 36. When a dark control design on the web reflects light on to the cell 59, the output current of the tube 75 falls, and the electromagnet r is sufficiently de-energized to release its armature r<6> when the switch member r<5> engages the contact r<2>, and thereby closes the circuit of the coil u which is thus energized from the mains terminals t, t<1>. The armature w of the coil u is then attracted and closes the contacts y, z to complete the motor circuit. This occurs each time a printed area x is opposite the aperture of the photo-electric cell, but provided the web is in register the effect is nullified by two rotating contactmaking cams 37, 38, driven synchronously with the breaker &c. mechanism. Each cam has a raised portion 37a, 38a adapted to raise a spring-pressed member 44, 45, so that contacts 50, 52 and 51, 53 are broken during part of the rotation, but are completed during the remaining period when the lower parts of the cam surfaces engage the members 44, 45, the contact screws 52, 53 being adjustable to regulate accurately the relative timing of the registration restoring operations. The cams are so adjusted that when the web is in register the member 45 is about to leave the high part of the cam surface 38a, while the member 44 has just engaged the high part of the cam surface 37a, at the moment that a registration mark x is reflecting light on to the photoelectric cell. In this event, the circuit of the motor 36 from the terminals 88, 89 through the generator 87 remains broken, but should the web be out of register when such a mark arrives, one or other of the members 44, 45 will be engaging the low part of its appropriate cam-surface, whereby the contacts 50, 52 or 51, 53 will be closed to complete the circuit of the motor 36, and drive it in an appropriate direction. The rotation so given to the shaft 32 serves to adjust the speed of the feed-rollers through the medium of the epicyclic gearing described above, and the intermittent correction is imparted so long as an error in registration occurs, such intermittent correction lasting as long as the spot x is reflecting light on to the cell and the low part of the cam permits the appropriate contacts to be closed. By varying the extent of this low part of the cam the time can be increased or diminished. If desired, the circuit may be modified so that the motor circuit is closed by an unprinted area of the web, when an increase in the amount of light reflected occurs, and special registration marks x<1> may be provided along the edge of the web when the ordinary designs x are insufficiently contrasting to the unprinted parts of the web. The cell 59 and the light source may be mounted on a slide operated by a screw, whereby their position transversely of the web may be varied, and both may also be capable of angular and vertical adjustment. If desired, the circuit of the motor 36 may be indirectly controlled by the contactor of the amplifying relay 74 and the cam-controlled contact arms operating through a relay as described in Specification 183,413.