GB288544A - Improvements in mechanism for guiding travelling webs - Google Patents

Abstract

288,544. Haubold Akt.-Ges., C. G. April 11, 1927, [Convention date]. Registering webs.-In apparatus for guiding travelling webs comprising pairs of guiding rollers engaging the edges of the, web and mounted on swivelling supports which can be turned in one direction by the pull of the web and in the other direction by fluid-pressure motors controlled by feelers engaging the selvedges, the supports are swivelled about axes lying under the edges of the web in the normal position of the web. The apparatus can be employed for guiding as a whole a transversely stretched web, or for guiding independently the edges of a web which is slack transversely. At each selvedge is arranged a pair of rollers c, c<1>, Fig. 1, constantly pressed together by springs g and mounted on a bracket e movable about a pivot i arranged beneath the edge of the web. The rollers c, c<1> lie normally at an angles to the run of the web due to the pull of the web, in which position an arm t of the bracket engages one end of a rod s<2>, Fig. 9, the other end of which is in contact with a piston r. This piston works in a cylinder s<2>, the outer end of which communicates with the atmosphere and the inner end of which communicates by a port with a second cylinder S<1> in which works a second piston p of shorter stroke than the piston r. A rod s<1> passing through the dividing wall between the cylinders S<1>, S<2> contacts with both pistons. The cylinders are connected by pipes p<1>, r<1> to a valve o, Fig. 1, which controls the admission of pressure fluid to the pipes p<1>, r<1> from a supply pipe n and the movements of the valve are controlled by a feeler l engaging the edge of the web h. A valve is provided in the pipe r<1> and when the apparatus is used for guiding transversely stretched webs, this valve is closed. In this case, upon lateral movement of the web h, the feeler l opens the valve o to admit pressure fluid to the pipe p'. The piston p is thereupon moved to the right and through rod s<1>, piston r, and rod s<2> moves the arm t from the position w of Fig. 9 to the position y, thus bringing the rollers c, c<1> to a position at rightangles to the run of the web. The continued pull on the web restores it to its correct path and the consequent closure of the valve o allows the pistons to return to normal position. When applied to a web which is slack transversely, the valve in the pipe r<1> is opened. In this case the normal position of the valve o is such that fluid pressure is admitted to the piston p to maintain the rollers c, c<1> at right angles to the run of the web. If the edge of the web moves inwardly away from the feeler l, the valve o is operated to shut off the fluid supply to the pipe p<1>, allowing the rollers to swivel, by the pull of the web, in a direction to extend the web laterally. If the web deviates outwardly, the valve o is actuated by the feeler l to supply pressure fluid to the piston r which, through the rod h<2>, moves the arm t to the position z of Fig. 9, thus moving the rollers to such a, position as to exert a contracting action upon the web.