GB716880A - Improvements in or relating to sheet feeding mechanisms - Google Patents

Abstract

716,880. Feeding sheets. BACKHOUSE, H. T. Aug. 25, 1952 [Sept. 3, 1951], No. 20794/51. Class 100 (1) Sheet-registering devices.-Sheets fed either singly or in underlapping formation over a feedboard 11 by conveyer means are prevented from over-shooting the front stops 13 by means of a suction gripper 16 which is raised through a slot in the board 11 to engage the front edge of a sheet, such as 12, and draw it down on to the board, the gripper being carried on one end of an arm 17 which is pivoted at 18 beneath the board 11 and has an extension 20 adapted to be engaged by a roller 23 on an oscillating arm 22. The downward return movement of the gripper 16 is effected by a coil spring arranged on the pivot 18, which also presses the face of the lever 17 into contact with a support block 25 on the board 11. In the raised position, the gripper 16 is connected through a passage 31 and a port 30 in the lever 17 with a port in the block 25 which communicates with a source of suction, so that the sheet 12 is gripped: as the gripper swings about the pivot 18, the port 30 moves into register with a port 29 in the block 25 which is open to atmosphere, and the sheet is re'eased. Preliminary stops 14 associated with the main front stops 13 are pivoted at 15 on the block 25, and are caused first to move upwardly and towards the advancing sheets, and then to reverse and travel back past the main stops 13 at about half the speed of the main sheet speed. This preliminary registration of each sheet is effected while the rear portion of the previous sheet (such as 38) is being removed over the top of the stops 13. The gripper 16 swings the sheet 12 forwardly as it is lowered. The degree of suction at the mouth of the gripper can be adjusted by providing two vent holes to atmosphere in the wall of the gripper, and fitting a hollow screw-threaded nipple into the mouth of the gripper, whereby these holes may be covered or uncovered, and also the effective area of the mouth of the gripper may be varied. Smoother-bars.-Pivoted bars 32 move downwardly, after the gripper 16 releases a sheet, to press the sheet against the board 11. Specifications 446,886 and 564,322 are referred to.