GB1496416A - Printing mechanism - Google Patents

Abstract

1496416 Shaft couplings QUME CORP 6 March 1975 [7 March 1974] 9403/75 Heading F2U [Also in Division B6] A disconnectible sheet feed drive mechanism, which may be used in a typewriter or line printing-machine, comprises a rotatable platen 13, a driving motor 39 connected through gears 38, 40 and 41 to rotate the platen 13 in steps and to hold it against rotation between steps, and a clutch interposed between motor and platen so that when the clutch is disengaged the platen 13 can be rotated independently of the motor, to determine the starting point for the next rotational step. The platen shaft 42 is journalled in a bearing 75 and has an axial bore 67 into which plunges a stub shaft 66 carrying a knob 15. A bevel-toothed clutch member 54 is secured by a pin 62 to the stub shaft 66, and the pin 62 passing through transverse slots 64 also keys the platen shaft 42 to rotate with the clutch member 54 but permits relative axial movement. The gear member 41, mounted for free rotation on shaft 42, is provided with internal bevel teeth 52, normally held engaged with the teeth of clutch member 54 by a bias spring 68. The clutch member 54 may have two segments removed, thus presenting two parallel side faces 56, 57, Fig. 4, which are engaged by two segmentally shaped projecting arms 72, 73, integrally formed on the output gear member 44 which is secured to shaft 42. Manual axial pressure on the knob 15, compressing the spring 68, can disengage the bevel teeth of members 41 and 54, thereby permitting the knob 15 to be used for manually adjusting the angular position of the platen and output gear 44, relatively to that of the input gear 41. In the embodiment of Fig. 3, a stepping motor 39 intermittently drives both the platen 13 and also a splined shaft 25 which conveys motion to two feed heads 34, each having a tractor belt carrying conical projections 27 which engage perforations in the document web margins. In another embodiment (not shown), two separate platens on a common axis may be provided, with separate feed heads 34, each having an independent drive means, and an independed manually - disconnectible clutch, thereby permitting two separate document webs to be adjusted mutually in relative position, for line printing side by side.