Patent GB-741153-A (GB)
Title: Transfer gripper system for rotary multi-colour printing machines for sheets of tin-plate and like material
IPC: B41F21/10
Filed: 1953-04-08
Abstract: 741,153. Rotary printing machines. MAILANDER, W. April 8, 1953 [April 8, 1952], No. 9517/53. Class 100 (2). In a multicolour offset rotary printing machine for printing on sheets of tin-plate or similar materials, a pair of printing couples are connected by a sheet transfer gripper mechanism having provision to reject sheets which are not taken by the grippers, or which slip out of the grippers after having been taken, and means adapted to stop the printing machine if a sheet, not correctly held in the grippers, is transferred to the second printing couple. The sheets are transferred from the impression cylinder 1, Fig. 1, of the first printing couple to grippers 9 moving in a circular path about an axis 28. The grippers are mounted on a spindle 11 and grip the edge of the sheet against a bar 10. The trailing ends of the sheets are held by holders 29 adjustable, according to the length of the sheet, to engage the trailing edge portion. Surround. ing the lower part of the path of the grippers 9 are a number of sheet guides 5 and a guide plate 7, there being a throw-out gap 6 between the guides 5 and 7 to allow sheets not held in the grippers 9 at the time they pass the gap to be rejected. The impression cylinder 3 of the second printing couple has grippers 12 carried on a spindle 14 and acting against a bar 13. Just beyond the point of transfer, guide fingers 15 are provided adapted to guide the sheets towards the printing point between the impressure cylinder 3 and the offset cylinder 4. In one form the guide fingers 15 are hinged by cross-spindle 23, Fig. 2, to members 16 mounted for swinging movement on a cross-shaft 20. The fingers 15 are biased by a spring 17 to the extended position (shown in full lines in Fig. 2), an abutment 19 bearing on an adjustable stop screw 18. A lever 25 fastened to the end of shaft 20 is subject to the pull of a spring 26 connected at the other end to a fixed point 27 and disposed so as to urge the shaft 20 to either of two over-centre positions. In the working position another arm 16<SP>1</SP> on shaft 20 engages the operating member 21 of a switch 22 controlling the driving motor of the printing machine. A sheet gripped, but not properly held by the grippers 12 will engage and displace the guide fingers 15 so that the spring 26 moves over-centre and moves the parts to the position shown in dotted lines in which the switch operating member 21 is allowed to move to the "off" " position and the machine is stopped. The lever 25 is adjustable so that the spring may, in the working position, be nearer or further from the dead-centre position. In a second form, Fig. 4, the guide fingers 15 are connected to levers 32 adapted to rock about the centre 33 of the impression cylinder 3. A misplaced sheet again engages and moves the fingers, rocking lever 32 against the action of spring 39. An element 41 mounted on one lever 32 is arranged to control the operation of the switch 22 as before. Offset continuations 34 of the guide fingers 15 are mounted behind fingers 15 on a common spindle 35. A stop 40 limits movement of the levers 32 under the action of spring 39 and movement of the lever in the other direction is limited to prevent the fingers 15 moving into engagement with the printing cylinder 4. The controlling switch may alternatively be mounted as shown at 22<SP>1</SP> to co-operate with arm 36.