1,030,695. Copying documents. BLOCK & ANDERSON Ltd. Aug. 15, 1962 [Aug. 22, 1961], No. 30296/61. Heading B6C. A duplicating machine for selective line copying comprises a rotatable printing drum having an axially movable clip 13 for securing a master to the drum, the clip being connected by a rotatable coupling in the drum to a chain 12 or like flexible coupling which passes over pulleys 15 to electro-mechanical means exterior of the drum for effecting lengthwise movement of the chain in steps of predetermined dimension to alter the position of the clip axially of the drum. In the diagrammatic plan representative of such a machine as shown in Fig. 1 the clip is moved by the chain 12 against a spring 17, the chain being anchored outside the drum to a non-rotatable nut 11 which is moved axially of a threaded rod 10 on rotation thereof. Such rotation is effected from a motor 21 through a reduction gear 20 and an electrically operated clutch 18. The rod 10 also carries part of an electromagnetic brake 22 the other coacting of which is secured to the frame of the machine. The rod 10 also rotates a worm 23 and hence a wheel 24, shaft 25, disc 26 and control disc 27. The disc 26 is secured to the shaft 25 whilst the disc 27 is mounted on the shaft 25 and has a lost-motion connection to the disc 26 through slot-and-pin connectors 29, 30 and a spring 31. The electrical circuit connecting the motor, clutch and brake is such that when the clutch is " in " the brake is " off " and vice versa, this arrangement being effected by a pivotally mounted switch 32 which moves from the clutch " in " to the clutch " off " positions in dependence upon the position of a pin 28 on the control disc 27 relative to the switch 32. Included in the electrical circuit is a reversing switch 52 for the motor and a transformer 82 supplying low-voltage current to the clutch, brake and switch 32. The disc 27 carries a plurality of upstanding pins 28 of even height and taller pins 28a, 28b. The spacing of the pins determines the step dimensions of the clip and each pin is adapted to coact with an actuating roller 35 of the switch 32 the taller pins 28a, 28b also being adapted to coact with a spring-biased lever 43 pivoted at 44. The switch 32 is carried by a plate 33 which is pivotally mounted at 34 on the frame of the machine, is spring loaded away from the disc 27 and carries a manually depressible button 36 and a post 37, the latter coacting with one extremity of a lever 38 pivoted to the frame of the machine at 39. At its other extremity the lever 38 is adapted to coact with an arm 48 which is slidable longitudinally through manual actuation of a button 47 carried thereon and is pivotable about a stud 50. At its inner end this arm 48 contacts a pin 28 on the disc 27. Assuming the nut 11 is at some distance from its lefthand limit and that the roller 35 is engaged and depressed by one of the pins 28, then the switch 32 is in the position shown with the brake energized and the clutch " off." The button 47 provides single-stop control. Manual depression of this button moves the control disc 27 through pushing its contacting pin 28 such that the roller 35 is released from the constraint imposed thereon by the pin 28 which it is contacting to allow the switch 32 to reverse to deenergize the brake and energize the clutch. The continuously rotating motor then rotates the rod 10 to move the nut 11 and hence the clip. The discs 26 and 27 are simultaneously rotated through the worm drive 23, 24 causing a pin 28 adjacent to the one originally imposing constraint to engage the roller 35 and thus reverse the switch 32 once again to stop rotation of the rod 10. Continuous movement of the nut and clip equal to a number of unit steps may be obtained by manual operation of the button 36 to a limited extent. This limited movement rocks the plate 33 to move the switch and roller to a position where the latter lies out of the path of the pins. Simultaneously the arm 38 is moved by the post 37 to rook the arm 48 clear of the pins. The clutch is now engaged and the brake is freed such that the nut, and hence the clip, moves until the button 36 is released whereupon the next available pin 28 engages and operates the roller 35 to initiate the stopping of the nut 11. If the button 36 is depressed to the full the post 37 becomes engaged behind a notch 45 of the lever 43 and rotation of the rod 10 continues, even if the button is released, until a limit-defining one 28a of the pins 28 engages the inner end of the lever 43. The resultant de-energization of the clutch 18 and energization of the brake 22 causes the rod 10 to be arrested and held at the limit position of the nut 11. Return movement of the rod 10 to bring the nut and clip to the opposite limit position in readiness for a further series of clip-shift operations may be obtained by use of the reversing switch and operation of the press button 36 to its intermediate position. If desired a second system of button and associated lever arms coupled with means for automatically operating the reversing switch 52 may be provided to allow both unit and multiple step movement to be available in the reverse direction. Some or all of the pins 28 may be displaceable axially to a position where they are also operative upon the lever 43 to provide a chosen pattern of successive clip movements in response to a series of full depression operations of the button 36. In a further embodiment the motor 21, Fig. 4, is non-reversible, operation of the switch 52 being used to select the required rotation of the rod 10 through the energization and deenergization of the clutches 18, 80 and vice versa. The switch 32 is actuated by a panel of push buttons 65 the set of four on the left of Fig. 2 being used for leftward movement of the clip whilst the set of four on the right of the figure are available in order to move the clip to the right. Each button 65 is mounted on a slidable control bar 61L, 62L, 63L, 64L and 61R, 62R, 63R, 64R. Depression of the button associated with either 61L or 61R causes, among other things, a bar 60 to move and operate the switch 52, this switch selecting the required rotation of the rod 10, through control of the clutches 18, 80, in dependence upon which button is depressed. The inwardly moving bar also removes the roller 35 from a contacting pin 28 thus freeing the disc 27 and reversing the switch 32. The clip 13 is accordingly moved through one unit step before the next following pin 28 contacts the roller 35. Depression of the button associated with either 62L or 62R allows the clip to move regardless of whether the button is held operated or released until a limit pin 28a or 28b, or a downwardly displaced plunger head on any one of the other pins, engages a release lever 72. Control bars 63L, 63R, operate in a similar manner to 62L. 62R, except that clip movement continues only as long as the appropriate button is held operated. When either of the buttons associated with the bars 64L, 64R is operated the clip 13 is moved continuously up to the chosen end limit. When either of these end limits is reached a projection 77 on the disc 27 opens an appropriate limit switch 55 or 56 thereby preventing further engagement of the particular clutch which has previously been operative to reach that limit position. In either embodiment the disc 27 may be made interchangeable with other discs having pins 28 at different spacings. A multiple unit space machine may be provided by arranging several discs 27, having different pin spacings, in stacked relationship upon a shaft 25 and then selecting which of the several switches 32 (and 52) is to be operated by means of a separate selector switch. In a further embodiment, not shown, the various control buttons are arranged to operate electric switches which. in turn, control the energization of a system of relays and electromagnets which provide for controlled movement of the switch 32 and interlocking facilities analogous to those described above. The invention may be applied to a machine having two movable clips. The rod 10, or rods in the case of two clips, may be disposed within the printing drum to rotate in unison therewith suitable connections being provided to the external control means.