GB865103A - Improvements in or relating to rotary printing machines - Google Patents

Abstract

865,103. Rotary printing machines; printing surfaces. DAVIDSON CORPORATION. Oct. 6, 1958 [Oct. 29, 1957], No. 31777/58. Class 100(2) A rotary printing press 10 includes a cylinder 11 having a peripheral slot 14 disposed parallel to the cylinder axis and a clamping device 15 secured in the slot for gripping the leading edge of a flexible sheet, the clamping device 15 comprising a supporting bracket 18, a clamping member 24 pivotally supported in the bracket, means for locking and unlocking the member 24 to and from sheet clamping position, and cam actuated means for pivoting the member from a sheet clamping position. The machine 10 may be as described in Specification 746,128 and has a plate-platen cylinder 11 and offset cylinder 12 mounted between frames 13. The clamping device 15 for the master sheets is identical to the device 17 provided for the copy sheets. The bracket 18 is fastened to the wall 19 of slot 14 and has a stop portion 22, against which the sheet to be clamped is positioned, and an anvil portion 23 against which the sheet is held by the gripper member 24 pivotally journalled on a rod 25 itself pivotally journalled in end pieces 18a of the bracket 18. The member 24 comprises gripper fingers 27 that extend between the stops 22. The fingers 27 are normally spring-biased into sheet gripping position. An ejector strip 30 is fastened to arms 31 pivotally secured to bracket 18 at 32. The strip 30 is connected by springs 34 to the member 24 so that as the latter moves out of clamping position the strip 30 is urged upwardly. Rigidly fastened to rod 25 is a link 35 having a roller 36 which co-operates with cams 55, 63 fixed to the machine frames and which may be moved from an inoperative to a roller contacting position. Also fastened to rod 25 is an arm 38 carrying a cam 37 which co-operates with a roller 39 on a lever 40. The roller 39 is spring biased into engagement with the cam 37 and the lever 40 is pivoted between legs 44 extending from the bracket 18. Lever 40 also carries a roller 46 adapted to abut against the flat head 50 of a screw 49 provided in an arm 26 of the member 24. Arm 26 is connected to cam 37 by a pin and slot connection 47, 48. The member 24 is locked in clamping position during printing by the action of roller 46 on the flat head 50. In operation as the cylinder 11 is brought round to the feed station 58 of the station roller 36 contacts cam 55 thus pivoting cam 37 in a sense to raise roller 39 from its position abutting flat head 50 so that the clamp 24 is no longer locked. During this initial movement the clamp 24 does not move owing to the slot 48. Further pivotal movement of cam 37 however raises the clamp 24 sufficiently to allow a sheet to be inserted over the anvil 23 and under the fingers 27. During this operation lifting of the ejector strip 30 is prevented by a rise 62 on the arm 31. As the cylinder continues to rotate the roller 36 rides off cam 55 and the parts return to the position shown in Fig. 3. When the sheet is to be ejected the roller 36 contacts cam 63 the shape of which is such as to give a greater pivotal movement to cam 37 and thus cause lifting of the ejector strip 30 as well as of the clamp 24 and so lift the edge of the sheet for engagement by a stripper plate 65. The roller 36 only contacts the cams 55, 63 when these are moved into operative position. The roller on the clamp 17 for the copy sheets, however is made wider so that the cams 55, 63 are contacted during each cycle of the machine.