Patent GB-635919-A (GB)
Title: Improvement in typewriting machines
IPC: B41J23/06
Filed: 1947-06-24
Abstract: 635,919. Typewriters. UNDERWOOD CORPORATION. June 24, 1947, No. 16694. Convention date, Dec. 31, 1942. [Class 100 (iv)] In a power-driven typewriting machine of the kind having a carriage traversing a framework and a series of normally quiescent actuators 25 for the type actions that are selectively brought into engagement with a power element, means are set in response to a line-end letter space for preventing engagement of the actuators 25 with the power drive. Depression of a character key 35 causes an actuator 25 to be driven from a power shaft 34 to cause a type bar 17 to print as described in Specification 635,916. In the present instance the actuators have rearward extensions which normally overlie a sliding bar 73 having a series of teeth 74 between which the extensions pass when a key 35 is depressed. When, however, a line end is reached a right-hand marginal stop on the carriage engages a stop finger 65 of a lever 64 pivoted at 62 on the main frame and moves it to the left and in so doing pivots a lever 77 which causes the slide 73 to move to the left so that the teeth 74 of the slide underlie the extension pieces of the actuators 25 and thus prevent their engagement with the power shaft 34. A spring- loaded catch 78 pivoted to the lever 77 allows the lever 64 to move without operating the slide 73 should the latter be jammed. The stop finger 65 is held to the left during a period of carriage return, and thereby keeps the slide in position to prevent operation of the actuators. The carriage return is effected by the operation of a key 123 and lever 146 which by means of a pin 124 opens a latch 122, thus allowing a lever 118 to be moved anticlockwise by a spring 115, Fig. 6, so as to cause the engagement of a clutch 95, 96 with a continuous drive which winds up a tape 94 on a pulley 92. The .other end of the tape first partially rotates a pulley 104 to cause line spacing as described in Specification 530,359, and then draws the carriage in a return direction. The rotation of pulley 104, causes-a a pin 142 thereon to engage a carriage length slide bar 136 which is thereby lowered on diagonal slotted bearings 138 to depress a nose 135 of one member 128 of a toggle mechanism 126, 127, 128, pivoted to the lever 118, the nose having been raised when the lever 118 was released. A pin 132 on the toggle lever 128 holds to the left, a link 134 attached to the lever 64, thus maintaining the slide 73 in a blocking position. When the carriage return movement is completed, the right-hand marginal stop engages the stop finger 65 and moves it to the right, thus restoring the lever 118 and disengaging the clutch 95, 96. The carriage-return key 123 is interlocked with a tabulator key 156, tabulator stop setting key 162, and a back spacing key 150, each of which has an associated depending portion which can enter a space between rollers 151, any one key being sufficient to crowd the space formed in a member 155 and thus prevent the operation of a second key. Underlying the character keys 35 is a continuous strip 152 to fill the space in the member 155 therebelow. In an alternative design the character keys 35 may be interlocked with the other keys and have depending portions coacting with further rollers 151 used in place of the strip 152. The carriage return key 123 carries a pin 159 which depresses a separate Lever 147 into the locking device so that should key 123 be released before the return movement is effected the lever 147 is held in locking position by a link 165 engaging beneath a rear portion 167 of the lever 147 which is held to the left by a link 166 attached to the clutch mechanism and is thereby raised by the action of a cam 171 in.a slot 168 in the frame 11. The tabulating mechanism is similar to that described in Specification 632,717. The carriage can be released to travel beyond the marginal stop by lowering the lever 64 on a slotted connection with the pivot 62 by means of a marginal release key whose tail-piece engages a lever 84, coacting with a stud 85 on the lever 64. The Specification as open to inspection under Sect. 91 describes means whereby the clutch 95, 96 is automatically engaged to effect a carriage return movement in response to the carriage reaching a line-end position. This subject-matter does not appear in the Specification as accepted.