Patent GB-699978-A (GB)
Title: Flat bed and cylinder printing press
IPC: B41F3/42
Filed: 1951-01-12
Abstract: 699,978. Printing machines. MONTGOMERY, W. G. Jan. 12, 1951 [Nov. 24, 1950], No. 923/51. Class 100(ii) [Also in Group XXIV] Printing machines; starting and stopping arrangements; driving arrangements. (Figs. 2, 3, 6, 8, 9 and 10). A flat bed and cylinder printing press comprises a reciprocable bed and a rotatable cylinder or cylinders disposed in co-operative relationship, means for reciprocating the bed with full harmonic motion, and means operatively connected to the bed reciprocating means for driving the cylinder or cylinders in one direction only so that the peripheral speed thereof coincides with the speed of the bed through two complete revolutions for each reciprocating cycle of the bed. As shown an electric motor 48a drives, by means of sprockets, sprocket chains and a pinion 49 keyed on a shaft 44, a crank gear 50 on a shaft 51, the gear 50 having mounted thereon an eccentric roller 56 which operates in a vertical groove 58 formed in an enlarged portion 59 of a yoke 60. The yoke 60 is thereby reciprocated on its roller bearings in such a manner that a rack 62 carried by the yoke causes oscillatory motion of a pinion 72 which is keyed on a transverse hollow shaft 73. The shaft 73 has keyed thereon bed moving gears 76, 77 which respectively engage racks 78 and 79 on the lower side of the bed 30, the bed being mounted for reciprocation on roller bearings 89 running on track bars 39, 40. The bed 30 is thus reciprocated in the opposite direction to the yoke 60 so that movement of the yoke 60 effectively counterbalances the forces created by movement of the bed 30. The hollow shaft 73 has a shaft 97 extending therethrough driven at one end by a sprocket 99 and chain 100 which extends over a smaller sprocket keyed on the shaft 44. The opposite end of shaft 97 has a bevelled gear 102 thereon which serves to actuate clutch mechanism in the cylinder driving unit 103. The unit 103 comprises an oil tight housing 104 at the inner side of which is the bed driving gear 77. At the opposite side of the housing 104 a cylinder driving gear 105 is fixed for rotation therewith. Also within the gear 105 is a gear 106, supported for rotation on housing 104 by a bearing 107, and oscillated in the same manner as gear 77 but in the opposite direction by means of a pinion 108 keyed on a shaft 109 in turn driven by an oscillating pinion 112 meshing with the bed drive rack 79. The housing is rotatably supported by a roller bearing unit 114. The clutch unit in the housing 104 serves to alternately connect the cylinder driving gear 105 to gears 77 and 106 so that it is always driven in the same direction. Gear 77 has a clutch ring 117 keyed on its hub with teeth 118 and gear 106 has a similar ring 119 with teeth 120. For co-operation with clutch ring 117 a ring 121 is provided with teeth 122, this ring being allowed a limited axial novement. A similar ring 124 co-operates with ring 119. The rings 121 and 124 are actuated by a series of cam units 127 each unit comprising a cam disc 128 keyed on a shaft 129. The cam 128 has cam surfaces 133 and 134 co-operating with cam followers 136, 137 at diametrically opposite points and carried on rings 121 and 124 respectively. rhus as cam 128 is revolved by means of gear 102, and gear 138 on shaft 129 the housing is alternately clutched by means of teeth 118, 122 to gear 77 and by means of the teeth on the rings 119 and 124 :o gear 106. The combined effect of the constant rotation of the gear 102 and the rotation housing 104 is such that the cam makes one complete revolution for each complete reciprocation of the bed 30 and one half-revolution for each single movement of the bed in either direction, the alternate engagement of gears 77 and 106 to the housing 104 being such that the housing and consequently gear 105 is always driven in the same direction. The cylinders 32, 33 are driven from gear 105 by means of idler gears 139 and 140 and gears 150, 152 keyed on the shafts of cylinders 32, 33 respectively. The idler gears are mounted for co-operation with gear 105 by means of rigid links and the cylinder gears 150, 152 mounted for co-operation with the idler gears by means of similar links so that the idler gears may rotate about gear 105 and the cylinder gears may rotate about the idler gears when the cylinders are tripped, the drive to the cylinders remaining unbroken. Cylinder trips. (Figs. 3, 11 and 12). The mechanism for lifting the cylinders 32, 33 away from the bed 30 during the return of the bed comprises a rack bar 164 mounted on the side of the machine and in alignment with a cam 54 mounted on the shaft 51. The cam 54 has a groove 168 which receives a cam follower roller 169 carried by a gear segment 170 rockably mounted on a pin 171 fixed to the side of the machine. The gear segment 170 when rocked by cam 54 serves to move the rack bar 164 by means of a rack 172. The bar 164 is also provided with racks 174, 175 which cooperate with pinions 176, 177 respectively which when rotated serve to rotate eccentrics 181, 182 which oscillate adjustable links 183, 184 connected at their other ends to cylinder supporting eccentrics 156, 163 so that on movement of the rack bar 164 the cylinders are lifted clear of the bed. A similar arrangement is provided at the other ends of the cylinders. Gripper mechanism. (Figs. 2, 15. 18, 23 and 25). For transferring sheets printed in one colour at the cylinder 33 to the other cylinder 32 for printing a second colour there is provided a transfer mechanism 34. The mechanism comprises side frame members 188, 189 joined by transverse hollow tie rods 190, 191, and solid rods 192, 193. The frame is supported by means of the cylinder supporting eccentrics, and arms 194, 195 and 198, the latter pair of arms each being provided with arcuate locking members, Fig. 15a, (not shown) for attachment to the cylinder 33 eccentrics so that the entire frame may be swung upwardly to allow access to the inking rollers 1. The cylinder drive gear 150, meshes with a gear 209 keyed to the hub of a sprocket 212. For driving a sprocket 219 at the other end of the rod 192 the sprocket 212 has an internal gear 225 meshing with a pinion 227 keyed on a hollow shaft 228. At the other end of shaft 228 is keyed a pinion 231 meshing with internal gear 233 on the sprocket 219. Similar arrangements are provided for driving the sprockets at the other end of the unit 34. Sprocket chains, 223, 224 run over the sprockets these chains carrying gripper bars 235, 236. These gripper bars are actuated so as to take the sheet from cylinder 33 by a cam member 257 which serves to rock the bar 236, Figs. 26, 27, 28, (not shown) to grip the sheet, and a cam member 256 which rocks the bar 236 to release the sheet so that it can be gripped by known gripper mechanism on the cylinder 32. For correct registration the ends of the gripper bars are provided with gear segments 246, 247 and 252, 253 the segments 247, 253 co-operating with arcuate racks 266, 267 on opposite ends of cylinder 32 and similar racks on opposite ends of cylinder 33. The gear segment 246 co-operates with a set of teeth 270 on the pinion 227 on shaft 228, and with teeth 270a on a similar pinion 227a on a shaft 228a. The top gear segment 252 co-operates with a set of teeth 272 on the pinion 231 on the other end of shaft 228 and a similar pinion on the other end of shaft 228a. A set of inner gear teeth is also provided at the centre of the gripper bars cooperating with a pinion 278. Axial registration is provided by means of a roller 264 mounted on the sprocket chain 224 and co-operating with a cam surface on the corresponding side frame member 188, Fig. 19, (not shown). A sheet feed mechanism 290 and delivery mechanism are also provided. Slack may be taken up in the chain by means of adjustable brackets 282, 286. The press may be adapted for printing in more than two colours by the provision of extra impression cylinders, all driven from the gear 105 and extra transfer mechanisms all similar to mechanism 34, Fig. 30, (not shown).