GB876319A - Improvements in printing mechanisms - Google Patents

Abstract

876,319. Typewriters &c. INTERNATIONAL BUSINESS MACHINES CORPORATION. Sept. 22, 1959 [Sept. 23, 1958], No. 32285/59. Class 100(4) A printing mechanism having a single truncated spherical type head tiltable and rotatable for type selection as described in Specification 842,328 is provided with detenting means which are disconnected during the type setting movement but engaged to align the type head just before it effects impression. The type head 1 is so mounted on a carrier 26, which is pivoted about trunions 50 to effect impression, as to allow tilting and rotation relative thereto by the action of tapes 33, 43 as described in Specification 873,920. Attached to a block 6 which supports the type head 1 is a plate 14 having teeth 15 and in openings between these parts a member 16 is guided which is pivoted at 17 and has a projection 18 which can engage the teeth 19 on the lower edge of the type head 1. A lever 55 pivoted to a yoke 23 and guided in its slot 54 has an arm 57 engaging in an opening 58 of the member 16 and an arm 59 projecting below the yoke into engagement with a lever 62 which in turn engages a lever 64 pivoted on a stud 65 fixed to a carrier 51. A cam 68 on a sleeve 67 fixed on a shaft 52 normally engages a projection 70 of the lever 64 which through lever 62, and arm 59 pivots the lever 55 to disengage it from a detent teeth 15. The lever 55 engaging the member 16 pivots it downward against its spring 20 to disengage the projection 18 from the teeth 19. Impression is effected by a single rotation of the shaft 52 which by cams 84, 85 on the sleeve 7 engages a follower 72 to rock the carrier 26. The cams 84, 85 disengage before impression occurs the parts continuing to move under momentum until an arm 88 of a member 87 attached to the carrier 26 is engaged by an anvil 89 also on the sleeve 67, to produce a whipping action to effect impression. The position of the anvil 89 on the sleeve can be adjusted to vary the moment of its engagement with the arm 88. During rotation of the shaft 52 before impression occurs and after the type setting movement is complete a low dwell on the shaft 70 allows the lever 64 and hence the levers 62, 55 to pivot so that the member 16 rises to engage its projection 18 with the teeth 19 and a lever 55 engages the teeth 15 so that the print head is centred and locked when impression occurs.