Patent GB-873989-A (GB)
Title: Improvements in or relating to escapement mechanism for the carriage of a typewriter, permitting of obtaining at will a number of spacing distances
IPC: B41J19/58
Filed: 1958-04-15
Abstract: 873,989. Typewriters &c. PAILLARD S.A. April 15, 1958 [June 7, 1957], No. 11912/58. Class 100(4) An escapement mechanism giving variable spacing feeds comprises a pinion engaging the carriage rack and an escapement wheel fast thereto both freely rotatable upon a shaft on which a second escapement wheel is fast. The latter mounts the pawls controlling the first escapement wheel. A pinion 64, Fig. 1, to engage the carriage rack has an escapement wheel 65 fast to it both being freely rotatable upon a hollow shaft 61 with which another escapement wheel 58 rotates. The wheels 58, 65 have different numbers of teeth while a ratchet wheel 82 also on the shaft 61 has a sub-multiple of these. Depression of a key 14 acting through links and rods 2-7 causes a type bar 1 to strike while its boss 1c, for the smallest escapement movement of two units, acts through a bridge 43, stop 42, rocker 39, anchor 51, to insert a retaining pawl 57 in the wheel 58 withdrawing a pawl 50 which is moved in known manner to engage a stop 49, Fig. 3, so that on the reverse movement of the parts it engages the next tooth of the wheel 58 and allows a corresponding movement of the carriage. Escapement results from the pull of the carriage acting through the pinion 64, wheel 65 and a pawl 66, Fig. 3, which is pivoted on the wheel 58 and engages the wheel 65 under the action of a spring 70. Double this escapement, four units, occurs when the stop 49 is moved to the broken line position of Fig. 3 by a lever 47 which through rods and levers 46, 27, 24, 22 can be so moved if during striking of the type bar a projection 15 of a key lever 2 engages a bar 17. An escapement movement of three units occurs when a projection 16 engages a bar 18 as may occur when the levers 19, 20 are moved vertically by support 100 as in a case shift movement. Through a similar linkage the projection 16 pivots a lever 30, Fig. 4, to move the rocker 39 to the broken line position on its spindle 40. In this position movement of the rocker 39 by the bridge 43 does not engage the stop 42 but presses a piston 72 in the spindle 61 which by a ball 74 and pusher 75 pivots a retaining pawl 67, Fig. 3, to engage the wheel 65 and at the same time withdraws the pawl 66 so that on the reverse movement the wheel 65 allows an escapement movement of three units the wheel 58 and spindle 61 remaining stationary. By the provision or omission of differently shaped projections 15, 16 on different type bars and by varying the teeth ratio between the escapement wheels 58, 65 any desired variation of spacing movement can be obtained. Lever 108 when acted upon disengages the pawl to both escapement wheels to allow manual. movement of the carriage. Correct re-alignment of the wheels 58, 65 for re-engagement is ensured by a pawl 85 engaging the ratchet wheel 82. Back spacing. The back spacing key through a rod 107 pivots a lever 90 clockwise thus by a rod 89 disengages the pawl 85 from the ratchet 82; by a rod 92, pawl 93, Fig. 3, turns the wheel 58 backwards two teeth or four back spacing units; by a rod 97 moves the rocker 39 to the broken position, Fig. 4, so that a rod 102 can actuate the wheel 65 to produce three forward spacing units. Thus the carriage receives the net backward movement of one unit.