829,430. Rotary duplicators. RITZERFELD, W., and RITZERFELD, G. Oct. 22, 1956 [Nov. 5, 1955(2); Nov. 8, 1955], No. 32090/56. Class 100(2) A rotary duplicating machine for printing text portions or lines, which are spaced apart by more than one line on a printing master sheet, from the master sheet on to copy sheets in immediate succession or in a closer relationship than they lie on the master sheet, comprises a rotatable printing drum and a counter pressure element, switching means arranged in a circular arc being allocated to individual text portions or lines of the master sheet, the switching means being arranged for acting on a common electric switch controlling an electromagnet -for turning the counter pressure element into its operative and inoperative positions, the switching means being settable for pre-selecting portions or lines for printing. As shown in Fig. 1, the drum 1 with master sheet 2 is secured on a shaft 3 driven by sprocket and chain means from a motordriven shaft 51. An impression roller 10 carried in arms 25 pivoted at 26 is adapted to be swung towards the drum 1, against the action of a spring 29, when electromagnets 28 are energized, the latter each acting through a link 49 and two toggle arms 16, 17. The arm 17 is secured to the shaft 27 of the roller 10, and the arm 16 is mounted on an eccentric shaft 15 which is adjustable by means of a lever and link 12, 13. A stationary key-board arranged on a circular ring 154 comprises keys 152 which are depressible against the action of springs 153 to depress switching pins 156 in a circular flange 155 secured on a shaft 157 which is driven by a chain 160 and chain wheels from the drum 1. There are thirteen keys marked T1 to T13 corresponding to text portions or lines Z1 to Z13 on the master sheet 2. In the basic position of the machine, when the keys 152 are manually operated, the pins 156 are depressed inwardly where they are held by spring-urged balls engaging grooves in the pins, and these depressed pins lie in the range of a roller 164 on a stationary electric switch 165 in the circuit of the electromagnets 28. Thus, on rotation of the drum 1 and therewith the flange 155, the depressed pins 156 operate the switch 165 and cause the impression roller to engage the drum 1 for each depressed pin. The pins 156 can be returned to normal position by a device 166 which can be rendered operative or inoperative by hand. For printing a heading comprising a number of lines a key 171 is depressed to 'bring a segment 172 on the flange 155 into the range of the switch 165 and thereby uninterruptedly energizing the magnets 28 for the lines of the heading. For printing whole pages, a stationary eccentric 173 can be turned to hold the switch 165 closed, so that the roller 10 remains in engagement with the drum 1. In a modification (Fig. 3, not shown), the keys are again on a stationary key-board on a circular ring, but are held in their two end positions by the engagement of spring-pressed balls in grooves in the keys. When a key is depressed, its free end extends into the range of a roller adapted to close a switch in the circuit of the electromagnets 28. The switch and its roller are driven by chain and chain wheels from the printing drum 1, and the switch is connected electrically to two stationary slip rings to which current is supplied in a circuit including the magnets 28. There is a rotatable and manually-operated device for returning the depressed keys, and a segment can be depressed to enable the lines of the-heading on the master sheet 2 to be printed. In the third form, shown in Figs. 5 and 6, a shaft 203 which is driven from the shaft 3 of the printing drum 1 by bevel gears 201, 202, has secured thereto a circular flange 204 carrying switching pins 205. The latter are held in their end positions by spring- urged balls which engage grooves in the pins. A circular stationary key-board 208 carries keys 209 which can be depressed against the action of springs, for selecting text portions or lines Z1 to Z10 on the master sheet 2 when the machine is in its basic position. The depressed keys 209 displace corresponding pins 205 which come into the range of a stationary switch 212 when the drum 1 and pin flange 204 are rotated; thus the magnets 28 are energized, and the impression roller 10 swings into contact with the drum 1 in correspondence with each depressed pin 205. A manuallyoperated lever 213 returns the depressed pins 205 to initial positions. In this construction, there is a means which automatically depresses the appropriate pins 205 and sets the next text portion or line to be printed during the next rotation of the drum 1. This comprises a switching arm 219 having a rotatable pawl 220 and fixed to a flange 221 which is rototably mounted on the shaft 203, but under the action of a coil spring 222. A locking pawl 223 and a stepping pawl 224 pivoted on a pin 225 on the flange 204 are adapted to cooperate with a ratchet tooth 232 on the rotatable flange 221; normally the pawl 223 engages the teeth so that the flonge 221 is driven from the flange 204. The flange 221 carries a knob 228 whereby it can be set against the action of the spring 222. When the drum 1 is rotated, and just before the basic position is reached, the pawls, 223, 224 travel past a number of stationary pins 229 (of which only two are shown) which can be depressed at will. When only one pin 229 is depressed, this pin engages and rocks the pawl 223 so that the flange 221 with the switching arm 219 is rotated through one step relatively to the flange 204 under the action of the coil spring 222 and travels past the next switching pin 205, presses this into its operative position, and comes to rest between the adjacent pins 205. When two pins 229 are depressed, the switching arm 219 is automatically rotated through two steps relatively to the flange 204, and so on. The pins 229 may be depressed so that a number of succeeding lines are printed from the master sheet 2, but the selection may be such that, for example, one line is printed and two lines jumped, so that only every fourth line is printed. This automatically stepped switching arm 219 obviates the necessity of the manually re-setting of the keys 209. Specification 735,181 is referred to.