公开(公告)号：DE1281764B

公开(公告)日：1968-10-31

申请号：DEJ0027428

申请日：1965-01-20

Applicant: IBM

Inventor： HANFT ROY FRANCIS ,  O'DANIEL JEROME BEARD ,  PALMER LEON EDWARD

IPC: F16D19/00 ,  B41J1/60

公开(公告)号：GB1270919A

公开(公告)日：1972-04-19

申请号：GB5654370

申请日：1970-11-27

Applicant: IBM

Inventor： ABELL WILLIAM ALBERTUS JR ,  ISAACS CHARLES MILTON ,  O'DANIEL JEROME BEARD

IPC: B41J29/70 ,  B41J7/94 ,  B41J19/62 ,  B41J29/64

Abstract: 1,270,919. Typewriters. INTERNATIONAL BUSINESS MACHINES CORP. 27 Nov., 1970 [22 Dec., 1969], No. 56543/70. Heading B6F. Variable impression; back-spacing.-A variable impression mechanism as described in Specification 1,187,507, has incorporated therewith a back-spacing mechanism. The yoke 70 axially moves the cam-follower roller 50 into alignment with three profiles (61, 62 and 63, Fig. 2) of cam 60, to effect respectively a highprint velocity, a low-print velocity and a noprint velocity. Cam 60 additionally has a backspacing profile (64). Movement of the drive link 113 of the back-spacing mechanism (Fig. 3), is generated by a cam follower roller 117 that engages the profile (64) of cam 60 and is contiolled by a tab 79 that is carried by, and thus is responsive to the position of the yoke 70. During each cycle, print shaft 16 will rotate to drive cam follower 117. This motion will be ineffective, since the lower end 118 of a floating link 119 supporting follower 117, is free to waste the motion generated by the cam profile 64. When the yoke 70 is displaced to its back-space selecting position, wherein the follower roller 50 tracks on cam track (69) of profile (63), the tab 79 becomes aligned with the end 118 of floating link 119, thereby restraining its movement. The back-spacing profile (64) thereupon generates a motion of the link 113 to operate the back-spacing mechanism, but since the follower roller 50 is tracking on cam profile (63), no print stroke takes place. Letter-spacing; back-spacing.-Letter-spacing of the type-carriage 20 is accomplished by a mechanism like that described in Specification 983,549. As escapement pawl (23) is pulled outwardly, surface (23a Fig. 3) contacts a tab (110b) on back-space pawl (110) causing it to be pulled from engagement with rack 17. After letter-spacing under the influence of a main spring, both pawls (23 and 110) re-engage the rack 17. The back-space operation is generated by movement of the link 113, which causes clockwise pivoting of a bell-crank 114 about a stud 115 fixed to the carriage 20. The end (114a) of bell-crank (114) carries a pin (116) that engages an escapement permitting slot (110C) in the back-space pawl (110). Since pin (116) cannot move laterally with the pawl (110) engaging rack 17, the motion of link 113 will cause the stud (115) to move, carrying with it the carriage 20 back one letter space.