Patent GB-417459-A (GB)
Title: Improvements in platen-rotating mechanism for typewriters
IPC: B41J11/36
Filed: 1933-03-31
Abstract: 417,459. Typewriters. BECK, F., and EUROPA SCHREIBMASCHINEN AKT.- GES., 13, Mainzerhofplatz, Erfurt, Germany. March 31, 1933, No. 9674. Addition to 409,003. [Class 100 (iv).] Platen rotation for tabulating ; margin stops.- To the line-space tabulator of the parent Specification is added means for selectively connecting the operating lever and gearing to the tabulator disc, so that the lever may be used for simple rotation of the platen, as well as for the tabulating rotation. The platen 2, Fig. 2, is driven through gears 3, 4, by a ratchetwheel 5, with which engages a pawl 7, Fig. 1, mounted on the lever 6. The gear 5 is connected to the tabulator disc 9 by toothed members 11, pivoted to the gear 5 and normally pulled inwards by springs 12, but which may be forced out to engage a toothed ring 9<a> on the disc, by means of a cone 13 mounted on a spindle 19. The cone is normally kept in the active position by a spring 14, but may be pressed in by a knob 18, and held in the disengaged position by the engagement of spring jaws 22, Figs. 2 and 3, with a groove 19<a> in the axle 19. The jaws may be pressed apart manually by the slidable member 25, whose wedge - shaped tip passes between them, or the member 25 may be actuated automatically at the end of the forward movement of the lever 6 by the engagement of a stop 26 on the lever 6 with a cam-surface 25b on the member 25. Thus the tabulator mechanism may be disengaged before a sheet is inserted and the adjustment of the platen to the first writing line automatically engages it again. The stops 10 on the tabulator disc 9 engage a fixed stop comprising two pawls 33, 34 mounted on a swinging plate 38. The tabulator stop is adapted, on the forward movement of the lever 6 to pass over the pawl 34, which then springs back imprisoning it between pawls 33, 34. On the return movement of the lever, which is impelled by a spring drum 44, a boss 7<a> on the pawl 7 engages a cam surface 38b on the plate 38, and presses the plate down, so that the pawls are disengaged from the stop 10 and, when they are released by the next actuation of the lever 6, take up a position ready for the next tabulator stop. The stops 10 are set by a nose 29<a> on a ring-shaped lever 29, actuated by a button 31 ; a divided disc 48 mounted on the axle 16 of the tabulator disc permits the selection of the desired stops. The tabulator disc may also be rotated by the knob 18, which is keyed to the shaft 16 for that purpose. Provision is made to allow the free rotation of the platen in either direction when the pawl carrying plate 38 is depressed and the lever 6 is in inactive position, an adjustable screw 47 engaging the nose of the pawl 7 and lifting it off the ratchet wheel 5 in this position. An adjustable padded stop 45 on the casing limits the return stroke of the lever 6, and the stop 26, co-operating with an adjustable stop 46, limits the forward stroke. The tabulator stops are all pressed back into inactive position by a disc 56 actuated by pressure on the disc 48, and are held in either position by a ring-shaped spring 28, split up into fingers to engage the different stops.