GB712531A - Improved detector mechanism for stopping the sheet feeding mechanism of printing machines upon delivery of double sheets - Google Patents

Abstract

712,531. Feeding sheets. COLOR METAL AKT.-GES. Sept. 17, 1951 [Oct. 9, 1950], No. 21814/51. Class 100 (1) Detecting faulty feed.-A mechanism for interrupting the feed of sheets to a printing machine when a double sheet is delivered comprises a pair of spaced rollers 6 disposed in contact with the sheets to flatten them against the conveyor table 4 and a sheet contacting shoe 7 swingably arranged between the rollers and adjustable in the direction of the sheet thickness so that on the simultaneous passage of two sheets it is moved by the sheets against spring action away from the shaft 6a of the rollers and, in moving, causes the closing of contacts 10 putting the sheet feeding mechanism out of action. A bracket 1 has, pivoted at 1b, a forked arm assembly 11 carrying the shaft 6a and having a rearward extension 11e or engagement by a micrometer screw 12 whereby the distance of the rollers from the table 4 can be adjusted. The foot 7 is mounted on a lever 7a pivoted at 7c to the short arm of a bellcrank lever 8. An upward extension 7b of the lever 7a carries an adjustment screw 7e locked by nut 7d and adapted to bear on one of the contacts 10 on displacement of the shoe 7. The position of the shoe is adjusted by a screw 9 so that there is only the thickness of one sheet between it and the table 4. The screw 9 bears on the longer arm 8b of the bell-crank lever. A spring 13 biases the lever 7a towards the shaft 6a. Movement in the opposite direction resulting from the passage of two or more sheets under the shoe causes the screw 7e to close the contacts 10 which actuate a relay to stop the sheet feeding mechanism. Such movement of the shoe is limited by a lug 7g which abuts a stop 1f fixed to the bracket 1.