Patent GB-692112-A (GB)
Title: Ink ribbon feeding and reversing mechanism
IPC: B41J33/16
Filed: 1950-12-27
Abstract: 692,112. Ink-ribbon mechanism. VICTOR ADDING MACHINE CO. Dec. 27, 1950 [Jan. 10, 1950], No. 31380/50. Class 100(iv) Automatic reversing arrangements.-In an inkribbon feeding and reversing mechanism of the kind in which one of the ribbon spools is continuously driven through a friction drive in one direction and the other spool is driven in either direction by a reversible pawl mechanism, the frictionally driven spool 22, Fig. 6, is mounted on a sleeve 82 housing a spring 88 applying pressure between a friction disc 90 and a plate 98 attached to a unidirectional ratchet-wheel 100. Upon each operation of a calculating or like machine a main shaft 12, Fig. 4, is rocked and turns two cams 14, 16, one at either side of the machine. The cam 14, is connected by a link 40 to a bell crank 44, pivotal about the axis 28 of one spool 20, Fig. 3, and carrying a pawl 58 spring-urged into engagement with a ratchet wheel 34 having a bent-out lug 36 for engagement with one of several extruded holes 38 formed in the side of the spool 20. The other cam 16, at the other side of the machine, Fig. 7, is pivotally attached to a pawl 114 engaging a ratchet-wheel 100 co-axial with the second spool to effect unidirectional rotation of the plate 98, Fig. 6, attached to the wheel 100 and transmitting a frictional drive through a ring 102 to the disc 90 urged towards the plate 98 by the compression spring 88. Holes 92 in the disc 90 are provided for driving engagement with extruded flanges 38 on the spool 22. In operation, the ribbon' 18 is wound from the spool 22 on to the spool 20 by the engagement of pawl 58 with the ratchet-wheel 34 in the full line position, Fig. 4, and when the ratchet-wheel 34 is unable to rotate due to the ribbon being held against movement by its other end attached to the spool 22; the counter-clockwise movement of the bell-crank 44 causes the pawl 58 to ride up in a slot 54 in the bell-crank lever and move into the dotted position shown where it effects reverse rotation to unwind the ribbon from the spool 20. The other end of the ribbon is now wound up on spool 22 by the friction drive from cam 16, until spool 20 is empty whereupon the drive to ratchet-wheel 34 continues in the same direction and winds up the ribbon once more on the spool 20, the tension in the pawl spring 62 being enough to rotate the spool 20 against the friction drive to spool 22. The ribbon is held in tension during the reversing of the drive by a jockey roller 126, Fig. 4, mounted on an arm 128 pivoted for a limited movement on a stud 130 carried by a downwardly projecting part of a ribbon guide 122 over which the ribbon is led across a platen 24 to a guide 120, Fig. 7, leading the ribbon to the spool 22. A detent 66 and multi-tooth detent 104 co-act with ratchets 34 and 100, respectively, to prevent the rotation during return movements of the pawls 58 and 114. Spools construction; spool mounting. - The spools are retained on their respective spindles by arms 74, Fig. 3, hinged at 76 to the outer flange and having a slot engaging with an annular groove 78 in their spindles. The arm is retained in position by an embossing engaging in a hole in the spool flange. The extruded holes 38 are equally spaced around the inner flange so that the spool may be engaged in any position by either the disc 98 or by a protrusion 36 on the ratchet-wheel 34.