GB530975A - Improvements in or relating to platen printing machines - Google Patents

Abstract

530,975. Machinery guards; brakes. SOLDANS, Ltd., and DOCKREE, B. R. June 17, 1939. Nos. 17766 and 22597. [Class 80 (iv)] The platen 2 of a printing press is reciprocated by an eccentric 4 and connecting-rod 5, the forme being shown at 3. A guard grid 6 is carried by arms 7, 7a fast on a rod 8 pivoted in bearings 8a on the frame 1. The grid is also pivoted on short rods 9 so that it can move inwards towards the forme 3 against the action of a spring 10 which normally holds the grid in a substantially perpendicular position. The grid assembly 6, 7, 7a, 8 is reciprocated by a connecting-rod 11 connected to the rod 5. The rod 11 is pivoted at 12 to an extension 13 of the arm 7, such extension being formed as a step 14 in which the arm 7 rests. When the platen is fully open the grid 6 is in its uppermost position. As the platen moves toward the forme the grid drops until at a point roughly midway between the open and closed positions of the platen, the grid touches the upper edge of the platen. A lever 15 pivoted at 16 carries at its upper end a pin 18 in the path of the grid. At the lower end of the lever is a notch 19, Fig. 3, in which a pin 20 on a lever 21 is adapted to rest. In the event of the operator's hand or fingers coming into contact with the grid, the platen will push the grid and pin inwards to move the lever, release the pin 20 and allow the lever 21 to drop. The falling of this lever is utilized to tension a brake band 22 acting on a flywheel 23. The brake band is adjustably secured at 24 and its free end is connected at 25 to the lever which is pivoted at 26. The movable end of the band is arranged in the direction of rotation of the flywheel so that the flywheel itself tends to wind up the band 22. When it is desired to " wash-up " the press, the grid assembly has to be swung back. To prevent this from being done while the machine is running, a rod 27 connected to the lever 15 has a slot in which a pin 29 on a crank 30 on the rod 8 engages, Swinging back the grid assembly pulls the rod 27 and lever 15 and applies the brake. A throw-off. mechanism for the driving belt may be arranged to act simultaneously with the application of the brake. Where the machine is driven by an electric motor, the catch serving to hold the brakeoperating lever may be combined with a switch so that on release of the catch the switch is cut out.