Patent GB-269651-A (GB)
Title: Paper tape or strip saving device or means for telegraph and like instruments or machines
IPC: H04L13/06
Filed: 1926-01-20
Abstract: 269,651. Murray, H. S. R. Jan. 20, 1926. Paper feed for receivers, automatically controlling.-The driving wheel 17 of a telegraphic tapefeed mechanism is clutched, so long as signals are being received, to the driven shaft 8, which operates the mechanism in question. On the cessation of signals, however, the clutch is uncoupled after a short delay, so that the shaft ceases to be driven, or is driven at a slower speed, until further signals arrive. The clutch comprises a part 7 capable of axial but not rotary displacement with respect to the shaft 8, and a part 9 integral with the driving wheel 17, and capable of rotation but not of axial displacement with respect to the shaft; normally the parts are held in engagement by the spring 24. At each revolution of the driving wheel a projection 15, Figs. 1 and 2, on the sleeve 9 depresses the point of a lever 13, Fig. 2, which is pivoted at 14. The toe 13<a> of this lever engages a projection 12, Fig. 1, on a lever 10 and turns the lever upwards about its pivot 10<a>, so that the pawl 11 carried by the lever may move the ratchet wheel 3 through the space of one tooth, thus turning the shaft 2, Figs. 1 and 2. This shaft also carries a second ratchet wheel 21 which co-operates with a holding pawl constituted by the armature 18 of the magnet 19, which is energized every time a signal impulse is received. Thus, so long as signals are being received the shaft 2 keeps on being released by the armature 18 and returning to its resting position, with the stop 5 (which is carried by the ratchet wheel 3) abutting on the upper end of the pawl 11. When, however, signals cease to be received, the armature 18 functions as a holding pawl, and the shaft 2 is turned step-by-step until the projection 6, carried thereby, engages the sleeve 7a and presses the clutch member 7 to the left so as to disengage it from the drive 9 and to disconnect the shaft 8. The time lag between the cessation of signals and the disengagement of the clutch is determined by the setting of the adjustable stop 5, which fixes the resting position of the shaft 2. Slow motion gear. Instead of ceasing to rotate when signals cease to arrive, the shaft 8 may then be driven step-by-step. A cam 27 fixed to the wheel 17 bears on a finger 29 on a lever 28, and causes the lever to reciprocate so that a pawl 30 carried thereby acts upon a ratchet wheel 31 carried by the shaft 8 and so turns the shaft step by step at a reduced speed. Simplified mechanism. In a modification the shafts 2, 8 are arranged parallel to one another, the projection 15 engages directly with the teeth of the ratchet 3 at each revolution of the wheel 17, and the armature of the magnet, acting as a holding pawl, also engages the teeth of this wheel when the magnet is de-energized. When signals cease to arrive the wheel is therefore. turned step by step until a projection thereon engages and operates a clutch lever. The levers 10, 11, 13, and ratchet 20 can therefore be dispensed with, and the clutch lever is added in place of the projection 6.