Patent GB-614236-A (GB)
Title: Device for positioning a sheet and for indicating the approach of the sheet end on a typewriter
IPC: B41J29/48
Filed: 1946-02-21
Abstract: 614,236. Typewriters. PAILLARD & CIE. SOC. ANON., E. Feb. 2, 1946, No. 5411. Convention date, Feb. 22, 1945. [Class 100 (iv)] In a typewriter, a device set by a scale is provided for imparting a preliminary sheetfeeding movement to the platen to position the required first line of the sheet at the printing position, such setting also causing movement of a sheet-end indicator so as to position it in correct position relatively to the platen, to which it subsequently remains coupled. The devices which are shown in the figure spaced laterally from one another are enclosed in a housing 3, in which the shaft 1 of the platen 2 is journalled. A parallel shaft 5 has fixed thereto a crank 4 by which the preliminary movement is initiated, and a driving member 8. Freely mounted on the shaft 5 are a gearwheel 6 meshing with a pinion 7 on the shaft 1, and an intermediate member 21 with a segmental part 22 engaged by a friction brake 24. A bolt 26 fixed to a hole 9<1> in the member 8 extends through a slot 25 in the member 21 and carries a pawl 9 urged by a spring 10 into engagement with the teeth 12 of the gear 6 so as to form a one-way drive. A spring 11 attached to the member 8 normally holds the parts 4, 8, 21 in retracted position determined by a fixed stop 43. A two-armed lever 31 freely mounted on the shaft 5 has on one arm a pointer 32 moving over a scale 33 so as to he set according to the number of the first line to be typed and on the other arm a pawl 34 urged by a spring to engage teeth on a fixed member 36. On the pawl 34 is a stop 37. In the position of rest, a lug 28 on the member 21 engages a surface 27 on the pawl 9 to raise it. After the lever 31 has been set, the crank 4 is rotated anticlockwise and the arm 8 turns with it causing the surfaces 27, 28 to disengage and the pawl 9 to engage the teeth 12 to rotate the platen. As the pawl 9 moves forward, its nose 30 engages a second lug 29 on the member 21 to lock the pawl on the teeth 12. The members 8, 21 now move together until a projection 38. on a lever 39 pivoted to the member 8 engages the stop 37, whereupon the heel 40 of the lever engages a lug 41 on the member 21 and moves the latter forwardly relatively to the member 8 to free the pawl 9 from the action of the lug 29. At the same time the projection 38 which is below the lug 29 engages the face 30 of the pawl 9, so that the pawl 9 is locked on the teeth 12, and the pawl 34 is locked on the teeth 36 by the pressure on the crank and no movement due to inertia can take place. When the crank is released, the spring 11 restores the parts to their initial position On the platen shaft 1 is freely mounted a drum 14 with graduated sectors 20 which together with a scale R on the casing graduated according to sheet lengths indicate the number of lines remaining to be typed. A spring 15 engaging bosses 16, 17 on the drum 14 and pinion 7 respectively normally couples the drum frictionally to the shaft 1. When the crank 4, however, is rotated, one of a number of lateral pins 18 on the drum first engages a sector 19 on the member 8 and the drum is stopped, the spring 15 allowing of this. The drum is allowed to continue its rotation with the platen when the trailing edge of the sector 19 leaves the pin 8, at which point the drum is in a predetermined angular position with respect to the leading edge of the sheet. The graduations on the drum in conjunction with the scale R then afford an indication of the number of lines available for typing. Specification 555,208 is referred to.