Patent GB-189907284-A (GB)
Title: Improvements relating to Telegraphic, Telephonic, and like Systems and to Automatic Switching Apparatus therefor.
Inventor: DARDEAU LEON JOSEPH MATHURIN
Filed: 1899-04-06
Granted: 1900-05-05
Abstract: 7284. Dardeau, L. J. M. Oct. 10, A.D. 1898, [date applied for under Sec. 103 of Patents &c. Act, A.D. 1883]. Actuating valves. -Electric switching-apparatus is arranged at each of a number of stations placed in one circuit so that any station can communicate with any other, and cut out all the remaining stations ; connections are thus obtained with electrically-actuated valves. The apparatus for one station is shown diagrammatically in Fig. 6, and consists of three buttons 1, 2, 3, a line battery U, a local battery V, a rotatable cam E provided with a dial, two polarized relays J<1>, J<2>, an alarm S, and a receiver AV, which may be means for opening or closing a valve for water, air, or gas. The cam E is carried by a shaft C, which is rotated by clockwork or electromagnetically, but is stopped by a pin X on it engaging a lever Y at end of each revolution, and by a toothed wheel on its engaging an escapement lever, controlled by an electromagnet H, several times in each revolution ; at each stoppage a pointer on the shaft C stands at a number on the dial. Each station corresponds to one number, and has its cam E suitably set on its shaft C. Each relay may consist of a vertical solenoid containing a soft iron core carried upon a spring, its upper end being movable between the poles of a permanent magnet. The core of the relay J' normally touches a contact N, short circuiting the electromagnet H, but is removable by a + line current. The core of the relay J' lies on either side ; it is caused to close the local battery circuit by a - line current, and to open it by a + current. The buttons 2, 3 send - and + currents respectively from the battery U to line. In calling, the button 2 is pressed once, then the button 3 a number of times corresponding to the number of the station called, and then again the button 2 once. The first + current sent by the button 2 causes the relay J<2> at each station to close the local battery circuit through an electromagnet T, the lever Y, and pin X, contact being thus broken between Y, X, and the shafts C freed and moving a step. The + currents sent by the button 3 causes the relay J' to put the magnet H in circuit, and this to move the escapement lever, allowing the shaft C at each station to turn one step for each impulse of current. When the desired number is reached, the cam E at that station moves an armature AD from a contact AE, opening a short circuit across the receiver AV there. The armature AD at the calling station is also moved similarly by an electromagnet AH, to which current is supplied from the local battery V and a contact 10 below the button 3. The armatures AD are then held by catches. When the button 2 at the calling-station is depressed the second time, the relay J<2> at the desired station connects the alarm S with the local battery V through the armature AD and cam E. When a communication is finished, the button 3 is pressed repeatedly, returning all the station switches and cams to the starting position ; a second cam on each shaft C then raises the catch, permitting the armature AD to move back to the contact AE. All the stations can be called simultaneously by pressing the button 3 till the shafts C have made nearly a whole revolution, when a projection on each makes contact with a spring AM to connect the electromagnets AH with the local batteries by a connection not shown, and move the armatures AD.