Patent GB-190525131-A (GB)
Title: Improvements in and connected with Switch Boards.
Inventor: MILLS CLAUDE KENNEDY
Filed: 1905-12-04
Granted: 1906-10-25
Abstract: 25,131. Mills, C. K., [Vitous, M., and Hammond, W. P.]. Dec. 4. Telegraphs ; telephone systems.-A plug switchboard for use in telegraph, telephone, or other communication systems is constructed on the unit system, each unit containing a switch for earthing its own line-wire and a jack comprising a socket member and a spring member normally in electric contact, but separated when a plug is inserted into the socket member of the jack. Two units are shown in Fig. 1. The fire - proof insulating block 1 is fitted with the socket portions 4, Fig. 2, of the jacks, held in place by means of the screw 5 and the shoulder piece 6. A.n adjustable screw contact 7 upon the socket is arranged to make contact with a contact-piece 8 upon the spring member 9 of the jack. Each block is provided with two jacks, so that the incoming and outgoing ends of the wires may be connected to any other line. The spring members. are secured to the block by means of bolts 10, which serve also to connect together electrically the two spring members by means of the strips 11. Strips 13 connect the jacks to the line through fuses and lightning-arresters. The free end of the spring member is bent as shown, and extends within the socket member so that it may be engaged by the plug fitting within the socket. The plug, Fig. 7, is formed with a handle portion 6 covered with insulation 3 and a metallic stem portion which fits within the socket of the jack. The stem is provided with a pin 4 which has a rounded end adapted to engage the spring portion of the jack, the pin being surrounded by insulation 5. The barrel 6 is tapped at 7 to receive the threaded end of the stem 8<a>. The diameter of the barrel is increased at one end to receive an insulating bushing 13, within which fits a flat - cylindrical head-piece resting upon the shoulder 14. and having extending from it the spring 10, which normally contacts against the cutaway edge of the barrel 6. The bared ends of the two connecting-wires are each rolled into the form of a small flat coil, and introduced through the aperture 16. One wire 17 is laid against the disk 15, and the other 20 against a metallic disk 22 which contacts with the cylindrical end of the outer stem 4. An insulating disk 19 separates the two wires, and the wires and insulation are compressed tightly together when the stem is screwed into the barrel. The wire 17 is connected through the spring to the stem portion 8, and the wire 20 is connected to the plug 4. When a connexion is to be made, a plug having the conducting-wires connected therewith is introduced into a socket, the rounded end engaging the sloping face of the spring member 9 and bending it to the right. By reason of the resilience of the spring, circuit is not broken between the contacts 7, 8, but the sloping face of the contact 8 wipes over the contact 7, which is thereby kept clean. Upon the continued inward movement of the plug, the spring is further deflected, the contacts 7, 8 are separated, and the plug is held in position by the angle 9<x>. Either division of the line may be earthed, a switch lever 16 electrically connected with the strip 11 being moved to engage the bolt 18, which is connected with an earthed strip 19. Circuit-markers 22 within sunk recesses serve to identify the different circuits. When one plug is in position, another may be inserted within it, thereby deflecting the spring 10, opening the circuit through the first plug, and cutting in the second plug instead.