GB257640A - Improvements in line-spacing mechanism for typewriters - Google Patents

Abstract

257,640. Hardingham, G. G. M. April 2, 1925. Line-spacing mechanism; platen-roller couplings.-In a friction-feed line-spacing mechanism having provision for minute adjustment of the feed, a friction-pawl d<2> engaging a drum e on the platen f is carried by an arm d which is pivoted to a loose arm c on the spindle a<1> of the linespacing lever a and is connected by engaging gears d<1>, b<1> or the like to a fast arm b on the spindle. On raising the line-spacing lever,a, the feed-pawl is caused to grip the drum by the action of the gears during the initial movement of the arm b, and on further movement the arm c moves with the arm b and line-spacing is effected. The arm c has a member c<1> which abuts on a disc f<1> on the platen to limit the feed movement. On releasing the line-spacing lever, a spring k returns the arm b, the gears act to relieve the feed-pawl, and a pin b<2> on the arm b abuts on the end of a slot c<2> in the arm c and retracts the arm c. Instead of the pin and slot, the arm c may have a lug in the path of the arm b. The feed is regulated by a cam g which forms a back stop for the arm c, the cam being revoluble by means of a. finger-piece and being provided with a dial h set with reference to a pointer h<1>. The cam g may be replaced by a face cam provided with a dial which can be read from the front of the machine. The feed-pawl is grooved and the drum is made from fibre or hard rubber and may also be grooved. Carriage-releasing arrangements; platen-roller detents. - A releasing-bar j is depressed by a finger c<3> on the member c'. A friction-pad on the j normally engages the platen spindle or a drum thereon and prevents rotation of the platen.