GB414169A - Improvements in or relating to sheet delivery mechanism for printing machines - Google Patents

Abstract

414,169. Sheet delivery mechanism. BREMNER MACHINE CO., Ltd., Wharfedale Iron Works, and WATKINSON, R. A., 6, Grosvenor Terrace, both in Otley, Yorkshire. March 17, 1933, No. 8157. [Class 100 (i).] In a sheet-delivery mechanism for printing- machines of the bottom-feed type, wherein gripping means mounted upon intermittently rotatable carriers are adapted to transfer printed sheets from the impression cylinder to suitable delivery means such as endless chain and reciprocating platforms, there is provided a method of guiding the sheet removed from the cylinder to the delivery means which consists in causing the gripping means to retain control of the sheet while imparting to the gripping means a movement in a reverse direction to their normal rotation, whereby the sheet is given its initial movement towards its point of delivery prior to being released by the gripping means. The invention is described with reference to a printing-machine of the "wharfedale bottom-feed stop-cylinder type," in which the impression cylinder 30 makes one revolution which occupies half the cycle of operations and remains stationary for the rest of the cycle. The rotary support for the grippers 10 of the delivery mechanism consists of two side plates 6 which are spaced apart but connect together by a rod 7 and are rotatably supported in the machine frame 1, being driven by a gear 31 on the impression cylinder shaft which meshes with a gear carried by one of the plates 6. To each plate 6 is pivoted a bellcrank lever 8 carrying a D-shaped abutment bar with which co-operate the spring-pressed grippers 10, carried on a shaft 11 mounted in the levers 8. Each lever 8 carries a runner 16 normally maintained by a spring in engagement with a lever 18, fixedly mounted on a shaft 19 which is coaxial with the supports for the plates 6. The bar 7 constitutes a stop which limits the movement of the levers 8, 18. A lever 21 is fixed to one end of the shaft 19 and carries a runner 22 adapted to engage a lever 23, pivoted at one end to the machine frame and near the other to a rod 25 which is slidably operated from a cam 28. Normally the levers 18, 21 and shaft 19 rotate with the plates 6, and the grippers 10 are suitably opened by a runner 33 and a fixed incline 35 at the point a to take a sheet from the impression cylinder grippers and carry it to the position shown when the impression cylinder and therefore the grippers 10 become stationary. At this point, the sheet 37 is hanging with its tail edge still resting upon the impression cylinder, and the travelling delivery means 39 take up this tail edge and carry it towards the delivery point. When the sheet is partially laid upon the platform 39 the grippers 10 holding the upper edge of the sheet receive a dipping movement from the cam 28, which through the rod 25 lifts the lever 23, which in turn lifts the lever 21 and rotates the shaft 19, and thus causes the levers 18 to turn the bell-cranks 8 about their pivots for carrying the grippers 10 in a downward direction. During this movement, the runner 33 engages an abutment 41 for opening the grippers, so that the sheet is released. The abutment 41 is made resilient so as not to obstruct the grippers during their normal rotary movement. The travelling delivery means may be in the form of reciprocating platforms, or as illustrated, of endless chains 40, passing round sprocket wheels 44-47 in the direction shown, and carrying platforms 39 supported by cross-bars attached to the endless chains.