GB395055A - Improvements in tensioning devices for the feeding of sheets of paper in web form - Google Patents

Abstract

395,055. Feeding webs. HARRIES, A. W., 31, Cole Park Road, Twickenham, Middlesex. Feb. 1, 1932, No. 2981. [Class 100 (i).] In a rotary web-printing machine in which printing takes place during only a part of the rotation of the impression cylinder, the feed of the web through the couple being arrested during the non-printing period, and in which the web is fed continuously from the reel to form a loop from which the supply to the couple is drawn, devices are provided adapted to act alternately to tension the web between a guide roller and the couple during the printing period and to draw a supply from the loop and tension the web between the guide roller and a stationary guide at one end of the loop during the non-printing period. The web g, Fig. 1, is drawn continuously from the reel A by feed rollers b to form a loop g2 and passes over a stationary guide 2, and guide roller k, between the impression cylinder c and coacting printing cylinder and thence between feed rollers, the driving shaft f<1> of which may be driven intermittently as described in Specification 389,621. During the printing period the stretch of web between the roller k and couple is held taut by spring fingers n, Fig. 2, secured to a shaft m and held against the roller k by a spring t connected to an arm s on the shaft m. During the non-printing period, the fingers n are moved away from the shaft k, as shown, by means of a cam q, Fig. 1, on the shaft of the cylinder c acting through a rod p and arm o on the shaft m. During this period also, a cam y driven from the cylinder c allows a pivoted frame x to fall thereby drawing a supply of web from the loop g<2> and tensioning the web between the roller k and guide 2. This frame carries a pair of bars 4, 5 which co-operate with a fixed bar 3 to draw forward and tension the web, the tensioning being assisted by spring fingers 8 which are engaged and depressed by the bar 5 against the action of a spring 10 secured to an arm 9 on a shaft 7 carrying the fingers. During the printing period, the frame x is again raised, the upward movement of the fingers 8 being limited by a stop 11 in the path of the arm 9. Specification 389,246 also is referred to in the Provisional Specification.