Patent GB-190505577-A (GB)
Title: Improvements in Telephone Calls.
Inventor: GEYERMAN PETER THOMAS
Filed: 1905-03-16
Granted: 1905-08-24
Abstract: 5577. Geyerman, P. T. March 16. Telephone systems; tele. phone calls; telephone8.- Relates to a step-by-step party-line telephone system, suitable for rural districts with a limited number of subscribers, in which each subscriber can select any other, without the aid of a central exchange. Figs. I, II, and III show the construction of the calling-apparatus, and Fig. IV the arrangements for three stations only. The shaft 2, Figs. I and II, carries a cylinder 3, a toothed wheel 4, and a disk 5, and upon the surface of the cylinder are arranged spirally a number of studs 21, adapted to engage the stop-pin 20. The teeth of the wheel 4 act on the spring catch 27 so as to make and break contacts 23, 24 and so cause the electro-magnet 30 to rotate the ratchet-wheel 38. The shaft 39 of the ratchet-wheel carries an arm 41, Fig. 1, which moves over an insulating- disk 42, bearing a contact 43 arranged according to the number of the station. The shaft 39 also carries a tripping-stud 54 which normally engages the rod 51, pivoted at 52, so that the lower end of the rod 49, supported on the rod 51 by a stop 50, comes between the press pin 55 and the lever 45. The lower end of this lever 45 normally engages a notch 48 in the cylinder 3. The stop-pin 20 of the selecting-pointer 17 is mounted in a rocking frame 15, in such a way that the weight of the receiver on the rod 81 normally keeps the pin 20 out of contact with the cylinder 3. If subscriber a wishes to call subscriber c, he sets the pointer 17 opposite the letter c on the plate 14, thus bringing the pin 20 in the plane of revolution of the stud 21 corresponding to subscriber c. He then turns the loose crank 7 on theshaft 2 against theaction of a spring 10 through a complete turn in a direction opposite to that of the arrow in Fig. III, until the nib 72 presses the latch 73 against the pin 74. In this position the pawl 8 again engages the notch 9 in the disk 5, but the spring is prevented from rotating the cylinder 3 by the lever 45 engaging the notch 48. Subscriber a then presses his pin 55 and releases the cylinder 3, which is rotated by the spring 10 until stopped by the stud 21 engaging the pin 20. The rotation of the wheel 4 rotates the contactarm 41 at all the stations as described above, and, when the cylinder stops, the arm 41 will engage the contact 43 at station c. The rotation of the cylinder will also cause the lever 45 to close the springs 57, 58 at station a, while the rotation of the shaft 39 at all the stations will lift the rod 49 so that the contacts 57, 58 cannot be closed at any other station, so that secrecy is maintained. A ringing and talking circuit will thus be formed as follows : from earth at station a, Fig. IV, wire 61, contacts 57, 58, wire 63, telephone &c. 69, wire 70, line 71, wire 70 at station c, telephone &c. 69, wire 68, contact 43, arm 41, bell 75, and the line 67 to earth. The pointer 59 on the shaft 39 and the dial 60 show at each station when the line is in use and who is the called subscriber. On the receiver being hung up, the pin 20 is disengaged from the stud 21 and the cylinder 3 continues its rotation and returns all the ratchet-wheels to their normal position.