Patent GB-819708-A (GB)
Title: Improvements in or relating to receiving selecting mechanism for teleprinter machines
IPC: H04L17/16
Filed: 1957-07-24
Abstract: 819,708. Printing-telegraph receivers. SIEMENS & HALSKE A.G. July 24, 1957 [July 24, 1956; May 13, 1957], No. 23515/57. Addition to 717,657. Class 40 (3). In a printing-telegraph receiving mechanism in which the de-energization of the receiving magnet effects a control operation by release of its armature which in the inoperative condition and at the beginning of its release movement is not restrained by the members which it controls so that it acts with considerable momentum as these members when the electromagnet is de-energized, a setting member for rotational adjustment of the start and stop positions of the receiver shaft carrying selecting cam discs carries a locking lever operating to release and arrest the cam shaft and also a release lever which is controlled by the armature of the receiving magnet and is operatively associated with the locking lever to effect the release of the cam shaft and which has a curved surface extending for a distance approximately concentrically with the cam shaft and positioned to be operatively engaged by the armature which may be provided with an associated curved surface extending concentrically with respect to the axis of the cam shaft. In the arrangement shown in Fig. 1 the de-energization of the magnet 1 allows the operating bar 3a of the armature 3 under the action of a spring 2 to engage the curved surface 5a of a lever 5 which is pivoted on a bar 7 secured to the adjustable setting member 12 and is rocked so that its end is disengaged from the latch portion 16b of a lever 16 allowing its end 16a to be rocked against the action of spring 17 by a cam 14 on the receiving shaft 4 driven by a friction clutch. Subsequently the lever 16 is restored by the spring 17 to its normal position against an abutment 18 which can partake of slight adjustment. Towards the end of the revolution of the shaft 11, the lobe 10a of a cam 10 raises the restoring lever 6 so that its curved surface 6a engages the bar 3a and moves the armature 3 to the position in which it is held by the magnet energized by the stop element of the received signal. In the stop position of the shaft 11, the location of the arm 6b in the recess of the cam 10 moves the operating surface 6a away from the bar 3a so that the release movement of the armature 3 is unrestrained. The angular position of release of the cam shaft 11 and consequently the operation of the selecting cams in relation to the received code signal impulses is effected by rotation of the setting member 12 which carries the interlocked release lever 5 and latching member 16 and which is locked in the adjusted position: In the modified arrangement of Fig. 2, the interlocked releasing lever 35 and latching member 45 are pivotally mounted at 36, 43, on a setting plate 40 moved relatively to a scale 41 by a handle 39. The portion 35b provided with the curved surface 35a is inclined at an angle to the remainder of the lever 35 and to its plane of movement, and the portion 33b formed with the co-operating curved surface 33a is inclined relatively to the remainder of the armature 33 and is disposed at an acute angle relative to the portion 36b, as indicated in Fig. 3 (not shown). The arrangement provides an approximate constant ratio of the distance between the point of engagement of the surfaces 33a, 35a and the pivots 34, 36 of the armature and release lever respectively for the different adjusted positions of the setting plate 40.