Patent GB-156632-A (GB)
Title: Improvements in electric switches
IPC: H01H9/22
Filed: 1921-01-06
Abstract: 156,632. Mason, R. K. July 8, 1919, [Convention date]. Switches, without quick-action, switches, quickaction.-Relates to electric switch-fuses mounted in metal casings having open fronts normally closed by a hinged door, the switch mechanism comprising a movable fuse-carrying base or barrier carrying inwardly the movable switch contacts, and an interlock between the barrier and the hinged door for locking the barrier in its forward or "switch-off" position when the cover is opened and for locking the cover in its closed position when the barrier is in its rearward or "switch on" position. Several embodiments of the invention are described. In that as shown in Figs. 2 and 5, the rectangular casing 1 has a door 2 hinged at 5 and provided with sealing lugs at 6, the casing 1 having a false front 3 formed with an opening 4. The switch consists of fixed and movable insulating bases 7, 8, respectively, the former carrying fixed clip contacts 12 which are connected through terminals 9 to the circuit leads, and the latter carrying blade contacts 13, which pass through the base 8 forming fuse clips 10 on its other side. The actuating mechanism consists of pairs of parallel links 16 pivoted at their lower ends to pins passing through the casing 1, and at their upper ends to pins 17 attached, as shown, to the movable base 8. To one of the lower links 16 is attached a handle 18 pivoted co-axially with the lower end of the link on a pin 25. A spring 19 may be fitted between the pivot 17 and the casing 1, to produce a quick action after the link 16 has been moved over its dead-centre in either direction: a lost-motion mav be provided between the handle 18 and the link 16, by means of an eccentric pin 23 on the former co-operating with a segmental slot formed on the hub 22, which is integral with the latter. Fig. 8 shows a modified form of the switch, in which the handle 18<a>, is integral with the lower link 16<a>, and the links 16a are of a different form, each pair of links being connected by a link 27, provided to obviate undue stress on the barrier. Fig. 10 illustrates a form of switch designed for use in conjunction with cartridge type fuzes, the fuzes 11<c> being mounted on the movable insulating base 8<c>, which, in the closed position of the switch, co-operate with fixed clip contacts 12<c>, the latter being mounted on, but insulated from the base 1, by means of insulating blocks 7<c>. To .ensure quick action, the handle is connected, with or without, the interposition of a lost-motion device as described above, to the cranked lever 18<c>. The lower link 16<c> is pivoted on the pin 25<c> co-axially with the handle 18<d>, and has a lower extremity 19<c> bent at right-angles. Between the bent-over portion 19<c> and a similarly bent over portion 19<c> of the lever 18<c>, a coiled spring 19<d> is interposed. Switch mechanism, interlocking with lids.-The switch mechanism is interlocked with the lid bv means of a slotted bar 28 pivoted on the inside of the lid 29, the bar 28 having a longitudinal slot 30 which terminates at one end in an enlarged portion 31. The lower end of the upper link 16 is formed with a projecting lug 32, which cooperates with the slot 31, 32 in such a manner that the lid can not be opened unless the switch is in the full open position. A modified form of interlock is shown in Fig. 10, the slot. 31<c> of the link 28<c> being curved; the lid is here shown in the open position. In Fig. 8, the lug on the link 16<a> is shown replaced by one or more pins 32a. The use of this interlock with the double break switch described is intended to ensure that no live contacts are exposed when the lid is open. Bases, boxes, and cases. - The case of the switch shown in Fig. 12 is made in two portions; the rear portion containing the permanently live terminals is adapted to be fixed securely in plaster or cement, and the front portion, carrying the movable contact block, contacts, fuses, lid, and switch-actuating mechanism, is detachably secured to the rear portion by means of the hookedon projection 1<a >and the sealing screws and nuts 1<b>. Contacts.-Figs. 2 and 8 show a means for rendering the contacts on the base 8 self-adjusting in a lateral direction, consisting of bowed leaf springs 15-apertured to pass over the blades 13, and kept in position by transverse pins passing through the blades, the ends of the leaf springs resting on the base 8. In the type of switch for use with cartridge fuzes, this adjusting mechanism is omitted, the cartridge 11<c>, Fig. 12, fitting in the threaded aperture 10<c> of the insulating base 8<c> and the two poles of the fuze being connected to the rigid contacts 13<c> by means of conductors passing through the base. The Specification as open to inspection under Sect. 91 (3) (a) describes also a modified form of switch in which the fuse carrying barrier was stationary, the contacts in the rear of the casing being mounted on a barrier adapted to move forward to close the switch, its actuating mechanism being interlocked with the hinged cover by means of the type described above. This subjectmatter does not appear in the Specification as accepted.