Patent GB-290819-A (GB)
Title: Improvements in or relating to electric switches
IPC: H01H1/10
Filed: 1927-05-09
Abstract: 290,819. General Electric Co. Ltd., and Angold, A. E. May 9, 1927. Oil-switches; switches, quick-break; contacts. -One contact of a switch includes a plurality of strips spaced apart from one another and having edges formed with inclined faces, whilst the second contact is formed with corresponding faces for contacting with the inclined faces of the strips. A switch may comprise two such sets of strips forming fixed contacts, and the moving contact is formed with corresponding faces for contacting with the strips. Two sets 1, 2 of fixed contacts are provided one above the other on a panel, each set comprising five strips 4 spaced apart and secured together and to steel bars 9 which are riveted to tongues 11 on plates 12. The contact edges 16 are bevelled or wedgeshaped and the strips are extended back to receive conductors by interlacing therewith. The moving contact comprises four spaced plates 17, the front edges of which are bevelled to fit the bevels on edges 16, and the plates are reduced at the back to provide cooling spaces 19. The plates 17 are supported in a frame 20 pivoted on a spindle 21 which passes through extensions 22 of the lower rods 9, and are positioned in the frame by a spindle 23 and by the spindle 21 engaging notches 24 in the plates. Pivoted on spindles 23 is a lever 26 to which is connected a toggle 33, 35, which is maintained overset against a pin 38 to hold the switch closed against a throw-off spring 27 anchored between pins 29, 28, the latter of which is engageable in any holes of a series in the lever 26. During the initial closing movement, when the handle is being depressed into the position shown in Fig. 3, the spring 27 is stressed and tends to hold the pin 30 against the lower end of plates 17, so forcing them against the contacts 2. The spring tension is slightly relaxed after the toggle passes the dead-centre and moves against the stop 38, and similarly in the opening movement, until the toggle is moved past the dead-centre, the spring is tensioned slightly, whereupon the bar 30 engages the contact plates 17 to maintain them in engagement with the contact 2 during the opening movement. The pivoting of the plates 17 on the spindle 23 and the natures of the strips 4 are such as to allow limited lateral play for adjustment, excessive bending of the outer strips 4 being, however, prevented by screws 14 screwing into the bars 9. The contacts are perforated at 40, 41 and slotted at 24 for cooling purposes, and the spacers for the strips 4 may carry right angle extension to act as terminals. The lever 26 may be held closed by a catch or electromagnet. Fig. 5, illustrates the application of the invention, the highspeed breaker described in Specification 254,455 having a moving contact 42 pivoted at 45 and formed as a solid block engaging four strips forming the fixed contact. The strips are perforated to receive a rod 58 carrying knurled nuts 59 with spherical sealings 61 for equalizing members 62. A set of thrust rods 65, 66 is provided for each member, these causing the members 62 to act on the strips and ensure proper contact.