GB869722A - Variable spacing mechanism for typewriters - Google Patents

Abstract

869,722. Typewriters &c. OLIVETTI & C., S.p.A. Ing. C. July 22, 1959 [July 26, 1958; June 27, 1959], No. 25113/59. Class 100(4) A variable spacing escapement mechanism comprises a rack 4 urged in a letter-spacing direction 5 and held by one of three movable dogs 6-8 which are mounted to swing together about a shaft 10 into and out of engagement with the rack and to be moved in a counter letter-spacing direction by springs 13 when disengaged from the rack by a projection 19 of a selectively operated lever 20 which after guiding the movement arrests the dogs. Depression of a character key. moves a bail which rotates one lever 20 to give a spacing movement appropriate to that character. Counterclockwise rotation of a lever 20 engages its projection 19 with a guiding portion 16 of the dogs 6-8 rocking them about the shaft 10 and after their disengagement from the rack 4 allowing them to slide guided by the surface 16 in a counter letter-spacing direction until their projections 18 are arrested by the moved projection 19 and their slots 17 allow them to re-engage. Rocking of a lever 20 also withdraws a lever 24 from a fixed dog 28 allowing its spring 29 to engage it with the rack 4 and to stop its movement after a maximum of three units of travel if the dogs 6-8 have failed to reengage before the rack 4 moves. In a modification the single dog 28 is replaced by three levers one of which always arrests the rack after a small initial movement and holds it until the movable dogs, which do not have slots 17, can re-engage the rack after which the fixed dogs are disengaged and the escapement movement is completed. To alter the spacing effected by each of the levers 20 the mounting plate 22 can be swung about pivots 40 by a slide 43 to alter the position of the projections 19.