Patent GB-313515-A (GB)
Title: Improvements in or relating to paper feed controlling apparatus
IPC: B41F13/02
Filed: 1929-04-11
Abstract: 313,515. Vogtlandische Maschinenfabrik (vorm. J. C. & H. Dietrich) Akt.-Ges. June 13, 1928, [Convention date]. Feeding and registering webs.-In devioes for controlling the rate of feed of printed paper webs, of the kind wherein electric contacts control circuits for accelerating or decelerating the speed, two elements associated with the cylinder and together constituting the contact are rotated at the same speed during the period the contact is closed. In one form, Fig. 1, spaced conducting-strips 2, 3 around the control cylinder 1 are connected by slip-rings to relay coils 26, 27 adapted to control the direction of rotation of a motor governing the web feed. The edge of the web 15 passing above the strips 2, 3 is provided with spaced perforations 16, and a series of brushes 7 carried by a rotating shaft 8 mounted in a bracket 6 on the cylinder are adapted to be brought successively upon the perforated edge. One pole of a source of current is connected to the relay coils 26, 27, and the other pole to the brushes 7, the, arrangement being such that at normal speed the perforations register with the space between the ends of adjacent strips 2, 3 and neither relay is excited, any change of speed bringing a brush into contact with a conducting strip and producing a relay excitation which restores the longitudinal registration of the web. Alternatively the perforated web may be. guided by rollers which hold it in contact with the greater portion of the periphery of the control cylinder and beneath an electrically conductive band which is similarly guided by insulated guide rollers, one pole of a current source being connected to the band and the other to spaced conducting-strips on the cylinder, through a pair of differential relays. An air suction device may be used to control electric contacts in circuit with differential coils connected to the armature of the controlling motor. In this form the periphery of a control cylinder 1. Fig. 4, is provided with two adjacent recesses 38, 39 leading into radial bores 30 containing plungers 31 which are pivotally connected to lervers 32, 33 carrying contacts at their outer ends. The inner ends of the levers are connected to a common pivot 34. and springs 37 tend to force the plungers inwardly to hold the lever contacts against contacts 35. 36 on the hub of the cylinder. By connecting the recesses 38. 39 to internal conduits 40, 41 which are connected to an air suction device the plungers are held outwardly, this being the condition when the web 15 is fed at normal speed and its perforations register with the part of the cylinder between the recesses 38, 39. If a perforation comes above either of the recesses the vacuum in it is broken and the electric circuit is made to restore the web to its normal position. The two contacts connected to the poles of the current source may be in the form of strips disposed side by side around part of the cylinder, connection being established between them by a brush on the other side of the web. The relays may control switches whereby both of them are prevented from operating simultaneously, and a cut-out switch which becomes operative in the event of the paper tearing may also be provided. Specification 316,956 is referred to. The Specification as open to inspection under Sect. 91 (3) (a), comprises also a modification wherein selenium cells are used to control the web-regulating motor, two slightly spaced cells being disposed upon the periphery of a control cylinder and arranged so that one of them comes beneath a perforation in the web when the speed deviates from normal, a reflecting-hood being provided to enclose the end of the cylinder and form a stationary support for a number of electric lamps. Instead of perforating the web the difference in the transparency of printed and unprinted portions mav be utilized. Coatings of current-conductive colour upon the web, in conjunction with conducting brushes, may be used for controlling the regulating-motor. This subject-matter does not appear in the Specification as accepted.