GB433987A - Improvements in sheet feeding devices for printing presses and like machines - Google Patents

Abstract

433,987. Feeding sheets. BACKHOUSE, H. T., 12, Melina Court, St. John's Wood, London. Aug. 2, 1934, No. 22518. [Class 100 (ii)] Tripping-arrangements.-In connection with a device for feeding single sheets or an overlapping stream of sheets to printing-machines a detecting device is provided for detecting the feeding of more than a predetermined number of sheets at a time comprising a pressure roller 3 arranged to bear on the surface of the sheets being fed and to be lifted by an increased thickness of sheets and by its lifting movement to operate a trip device for stopping the feeding machine or the printing-machine. The roller 3 is mounted in an adjustable arm 4 so that its distance from a lower roller 2 can be regulated and an adjustable spring 7 maintains the rollers 3, 2 in contact. The roller 3 is preferably fitted with a rubber tyre 11, contacting with the sheets, and is formed with a surface 12 of a smaller diameter which engages a rubber contact 15 on a pivoted arm 13 mounted in an adjustable bell-crank lever 14. The arm 13 is normally held so as to keep the contact 15 out of engagement with the surface 12 by means of a roller 18 on a spring-pressed lever 19 which engages a notch 16 on the arm 13. If the roller 3 is raised by the passage of additional sheets it moves the arm 13 in a counter-clockwise direction, the motion being increased by the action of the roller 18 when it moves out of the notch 16 on to an inclined surface 17. The surface 22 of the arm 13 acts on a lever 23 on a tripping-shaft 24 which may be a square bar which is the equivalent of the bar 5 described in Specification 430,371. In a modification the arm 13 is replaced by a lever arm which operates the lever 23 by direct pressure when the lever is rotated in the same manner as the arm 13.