GB777727A - Improvements in or relating to sheet separating and forwarding machines - Google Patents

Abstract

777,727. Feeding sheets. BACKHOUSE, H. T. July 29, 1955 [Aug. 3, 1954], No. 22552/54. Class 100(1) Sheet forwarders:-In apparatus for separating and forwarding sheets one by one from the top of a pile in which an edge portion of each top sheet is raised from the pile and transferred to sheet-forwarding grippers which move with the sheet over the pile to conveyer &c. means and then return to engage the next sheet,'the forwarding grippers make at least the last part of the return movement at a height above that of a raised sheet portion and are then lowered to engage the sheet. The apparatus described is a modification of that described in Specification 427,041. Two separating and lifting suckers lift the rear edge portion 13, Fig. 2, of the top sheet of a pile 14 into a position just below the mouths of two forwarding suckers 12. The suckers 12 are then lowered by suctionoperated means to engage the sheet, the suckers rise a short distance with the sheet, move the sheet over the pile 14, release the sheet, and return to take another sheet, still in the raised position. Each sucker 12 is carried by a hollow shaft 22 supported in bearings in a head 21 attached to the end of a hollow piston rod 20 which is integral with a piston 19 in a cylinder 18. The cylinder body is secured to a rock shaft 15. A valve 26, which controls the application of suction to the cylinder 18, is automatically moved by a fork 34 thereon engaging a fixed bar 16 when the cylinder is oscillated by the shaft 15. Towards the end of the return stroke the valve 26 allows suction to be established to both ends of the cylinder 18, the piston 19 and sucker 12 are drawn downwardly of the cylinder against the action of a light spring 37 until the sheet 13 seals the mouth of the sucker, whereupon the sucker rises with the sheet. The shaft 15 is then rocked to move the sucker forwardly with the sheet, the valve 26 is moved to cut off. suction from the cylinder, the sheet is released, and the sucker is retained in the, upper position by the spring 37 until it returns to engage another sheet. The inclination of the sucker 12 is kept substantially constant during the oscillation of the shaft 15 by means of a rod 41 pivoted at one end to an arm 40 secured to the shaft 22, the other end of the rod having an abutment engaging the fixed bar 16. A pin 46 and stop 47 ensure that this inclination is preserved during the downward movement of the sucker. In a modification, Fig. 5, a rocker arm 52 secured to a rock-shaft 50 has pivoted thereon a link 53 which at one end is pivoted to a link 54 pivoted on a fixed bar 51, and at the other end is secured to a suction cylinder 56. This linkage constitutes a parallel motion system for the cylinder. The cylinder is open at its upper end and contains a piston provided with a relief hole therein which communicates through a hollow piston rod carrying the sucker 63. The cylinder is connected to a source of suction through a control valve. As before, the piston and sucker are drawn downwardly of the cylinder when suction is applied to the latter, and the sealing of the sucker by a sheet causes the sucker to rise; .this position is maintained by a spring until the sucker is swung back to receive another sheet.