Patent GB-538249-A (GB)
Title: Improvements in or relating to printing telegraph apparatus
IPC: H04L17/18
Filed: 1940-04-30
Abstract: 538,249. Type-printing telegraphy; clutches; relays. CREED & CO., Ltd. (Western Union Telegraph Co.). April 30, 1940, No. 7796. [Class 40 (iii)] [Also in Groups XXIV and XXXV] In a printing telegraph receiver of the kind in which the selecting members are all operated but the position to which each member is operated depends upon the character of the corresponding code element, the selecting members are invariably moved in a linear direction and are selectively acted upon by electromagnetically-controlled means interfering with said linear movement for a received code element of one nature so as to produce a combined linear and pivoting movement. The members are retained in their operated positions until a complete code combination is received and these determine the character to be printed, e.g. by setting permutation bars. The rotary cam sleeve for operating the selecting members is released by a pilot sleeve after an interval which can be adjusted to suit line conditions so that the middle portion of the code impulses may be utilized. Selecting mechanism. In the five-unit system described, five permutation bars 218, Fig. 2, are set by five latches 204, Figs. 2 and 8, controlled by five selecting fingers 157, Fig. 8, which are moved upwards in Fig. 8 in succession by five cams 68a ... 68e on the cam sleeve 57, and pass behind or in front of a knife member 189 according to the position of an extension 111 of the armature of the line magnet, this extension engaging shaped parts 198 on the selecting fingers during their upward movement. Some of the fingers are thus behind and some in front of the knife-member 189 and are retained in this position until all the fingers have been set, whereupon the knife-member is moved to the left by a cam 69 on sleeve 57 and causes those selecting fingers which moved behind the knife member to actuate by projections 203 the corresponding latches 204, thus allowing the corresponding permutation bars 218, Fig. 2, to be moved to the left by springs 221 to select and operate the type bars in known manner. Driving arrangements. The driving shaft 27, Fig. 3, carries three sleeves 74, 57, 36. The pilot sleeve 74, when released by the start impulse de-energizing the line magnet, is driven by a friction clutch 84 and after an interval, adjusted as described later, releases the cam sleeve 57, which is driven by a friction clutch and carries cams 68a ... 68e co-operating with the selecting members, a cam 69 mentioned above, and a further cam 71. Near the end of the revolution of sleeve 57, the cam 71 operates the trip lever 207 which allows a spring 239 to move a collar 46 to the left, so that teeth 49 thereon engage teeth 51 on a member 52 driven by the shaft 27. The sleeve 36, which rotates with the collar 46, thus makes one revolution and operates the printing cam 38. Clutches. In the friction clutch, the shaft 27 drives a disc 54 having three pins 59, Figs. 3 and 12, engaging in tangential slots in segmental members 62 in frictional contact with the hub 58 of the driven sleeve 57. A coiled spring 63 presses the members 62 against the hub 58. The claw clutch is formed with a side cam 243, Fig. 3, against which is pressed a pivoted lever 241 to put a drag or load on the driven member, thus preventing rebound or reverse rotation when the clutch is stopped, and also retarding the starting movement until the teeth 49, 51 are fully engaged. Adjusting release of cam sleeve 57 to suit line conditions. The pilot sleeve 74, released by the start impulse, carries a cam 79, Fig. 7, which releases the cam sleeve 57 at a point determined by the adjustment of lever 136 in a slot 128. The lever 136 has a pin 139 supporting two rollers 140, 141, of which roller 140 is engaged by the cam 79 and roller 141 moves a lever 133 to release the cam sleeve at a point determined by the angular position of the rollers. Construction of line magnet. To enable the armature gap to be adjusted, the magnet yoke 97, Fig. 7, and windings 98 are carried by a U- shaped frame 94 pivoting about the same axis as the armature 108 and pulled downwards by a spring 99 against an adjustable stop 104. The movement of the armature 108 is limited by a stop 122.