Patent GB-191020585-A (GB)
Title: Improvements in or connected with Devices for Making and Breaking Electric Contacts in Wireless Signalling Systems.
Inventor: VARLEY FREDERICK HENRY
IPC: H03B11/06
Filed: 1910-09-03
Granted: 1911-12-04
Abstract: 20,585. Varley, F. H. Sept. 3. Electro - magnetic interrupters. -Relates to electro-magnetic vibratory interrupters, used with induction coils for systems of wireless telegraphy, of the type in which a single vibrating reed operates two or more contact-levers in order to subdivide the spark at the break, and the invention consists in improved means for connecting the vibrating reed with the make-andbreak contact device, in the construction and adjustments of the vibrating reed and contactdevices for the purpose of accurately timing the interruptions, and in means for changing the rate of interruption by the action of the signalling - key. The vibrating reed d<1>, Fig. 1, is pivotally connected by a link d<3> to a pivoted cross-head f, Figs. 6 and 7, which lifts all the pivoted spring-retracted contact-levers g. The levers g are loosely mounted upon the shaft which rigidly carries the cross-head, retracting- springs being attached to the levers and to collars h<1> which are clamped adjustably to the shaft. The cross - head also has a steadying- spring f<2>, and is arranged to operate the contact-levers at or near the middle of a vibration. A weight may be substituted for the spring f<2>. For use with large induction coils, three, four, or more contact-levers are similarly operated, the object being to subdivide the arc. The separate breaks are either in series or parallel. The contact - levers are mounted upon a baseplate e<1>, which screws into the bottom of a box e filled with a dielectric fluid, the operating link passing through the top. Condensers are added to further diminish sparking. The electromagnet is mounted adjustably upon a bracket b, Figs. 1 and 2, which can be swung out on an axis b<2> when it is required to inspect the parts. To provide for adjustments of the vibratory reed, it is mounted between plates d<4>, d<5>, which are clamped together by one or more screws. The length of the reed free to vibrate can be altered by shifting the clamping-plates by screws d<14>. The clamping - plates and the reed are carried on a block d' mounted on trunnions in a bracket d<8>, and the block may be canted to either side by means of screws d<15>, so as to bring the armature nearer to or further from the electro-magnet. To effect a fine adjustment of the rate of vibration, a spring i is arranged to be pressed more or less firmly upon the reed. A cam gripping-device or a shifting weight may be employed instead. In a modification, Fig. 14, the fixed contacts g<1> are carried at the lower end of a tube g<4> capable of vertical adjustment upon a solid stem g<6> by turning a screw g<5>. In using the interrupter for signalling, the signalling-key is caused to act upon the spring, cam, or other mechanical device for changing the rate of vibration, and in addition to or alternatively to the mechanical device, the key is caused to throw a resistance shunt or condenser into the induction - coil circuit. The Specification contains diagrams of the circuit connexions for a two-lever interrupter, and a three-lever interrupter with all the breaks in series. In Fig. 20, a four - lever interrupter having two breaks in parallel and two in series is shown actuated by an electro-magnet c in circuit with an adjustable resistance l, the electro - magnet and the resistance being in parallel with the induction-coil k. Instead of a separate electro - magnet, the core of the induction coil may actuate the trembler blade.