GB944288A - Safety trip means for sheet feeding mechanism - Google Patents

Abstract

944,288. Feeding sheets. ROLAND OFFSETMASCHINENFABRIK FABER & SCHLEICHER A.G. Aug. 22, 1960 [Aug. 20, 1959], No. 28915/60. Heading B6B. In apparatus in which sheets are fed to a predetermined station, a feeler is supported by oscillating means positioned permanently above the plane of the sheet movement and is moved downwards in timed relation to the feed to intersect the plane of sheet movement. If sheet is fed too far forward, the feeler is arrested and causes a control to stop the sheet feed. As shown parallel shafts 12, 13 are mounted between side plates of the machine, the shaft 13 carrying two arms 14. A block 18 carrying a finger 19 is pivoted at the lower end of each arm 14. The fingers 19 rest on and slide over the upper surface of a sheet of paper 21 supported on a surface 22 and are biased into contact with the paper by leaf springs 23. In the position shown the sheet 21 has been fed forward to the correct extent by sheet feeding mechanism and its leading edge is in contact with the gripper lays. The spindle 13 is oscillated in timed relation with the feeding, mechanism so that the fingers 19 are slid over the surface of a sheet as soon as the latter has completed its forward movement. If the sheet is correctly positioned the movement of the parts 13, 14, 19 is unimpeded, but if the sheet has not been advanced far enough the end of one or both the fingers 19 engages in a slot 26 in the surface 22 and the shaft 13 is thereby prevented from completing its oscillatory movement. Arrest of the shaft 13 causes associated mechanism to stop the feeding mechanism. The shaft 12 carries a pair of blocks 27 on each of which is pivotally mounted a rocker 30 carrying a finger 32. A portion of each finger 32 normally rests in contact with an upper portion of the shaft 12 and is biased into engagement therewith by a spring 34. The shaft 12 is oscillated in timed relation with the sheet feeding mechanism and if a sheet has been correctly advanced the fingers 32 are moved to the position shown immediately thereafter. If a sheet overruns the lays the fingers 32 engage the leading edge thereof and are arrested in their downward movement. As the shaft 12 continues to rotate the fingers 32 are moved out of contact with the shaft and engage leaf springs 37 secured to the blocks 27 thereby completing an electrical control circuit which stops the machine to which the sheets are being fed. A second switch in the control circuit is operated by the shaft 12 and is closed only when the fingers 32 are approaching the position shown. A pawl 43 is pivoted to each of the blocks 27 and projects therefrom towards the arm 14 behind it. The lower surface of each pawl is normally either out of contact with or slidably engaged upon the upper surface of a stop plate 44 secured to the corresponding arm 14, but when the corresponding finger 32 is lifted clear of the shaft 12 a shoulder 45 on the pawl abuts the front end of the plate 44 whereby the shaft 13 is restrained against oscillation and the sheet feeding mechanism is stopped.