Patent GB-166286-A (GB)
Title: An improved electrical circuit breaker
IPC: H01H87/00
Filed: 1920-01-09
Abstract: 166,286. Illingworth, W. H. Jan. 9, 1920. Thermal switches, cut-outs, and interrupters; indicators.-Carriers or holders for mercury cutouts as described in Specifications 121,305 and 138,439, or for sinle or multiple-strand wire fuses, consist of two metal portions insulated from one another and adapted to contain a tubular core of refractory insulating-material, a divided insulated metal sleeve or casing rigidly holding together the two metal portions of the carrier as shown in Fig. 1, the two metal portions AB are insulated from one another by a mica. ring C, the upper member carrying a nut a<3> which serves as an abutment for the divided metal sleeve F, which is insulated by mica sleeves C<1>, C<2>, C<4>. A union nut f<2> is secured on the lower end of the sleeve F, this nut being insulated by a flanged mica ring C<5>. The metal sleeve F may be provided with an insulated porcelain handle F for operating purposes. The metalsheathed tubular core D of refractory insulating material is placed within the upper metal member A, and is supported on a mica tube C<3> within the lower member into which the lower copper contact b<1> is screwed. A metal cover A<1> is secured to the upper member, and has an internal deflecting-surface a<6> above the core, leading to the mercury well or overflow a<7> for the ejected mercury. The well a<7> is provided with an inspection window a, and an adjustable metal rod E connected to an alarm circuit, a filling-aperture a<15> being also provided which has a side passage a" acting as a release for mercury vapour. The core D is passed down on its suppcrting-tube b, forming a fluid-tight joint, either as shown in Fig. 1 by means of two pins a<12> carried by a transverse bar a<11>, these pins being pressed on the packing-piece a<8> above the core by means of a screw a<13> in a bridge-piece a<14>, or as shown in Fig. 4 by an adjustable metal block a<21> having a mercury-deflecting surface a<23>, which rests upon the core D. The upper contact may consist, as shown in Fig. 1, of a copper tube a<5> extending downwards from the cover A' within the central core passage d<1>, or, as shown in Fig. 4, of an adjustable block a<18> connected by a side passage d' with the central core passage d'. An extension b<5> of the lower metal member B forms one external carrier contact, the other consisting of an extension of the cover A<1> or the upper metal member B, by means of which the cut-out is pivotally mounted to allow for re-setting, a spring catch M co-operating with the cam m carried by the carrier contact, thereby maintaining the cutout temporarily in the tilted position. Two or more cut-outs may be pivotally mounted to form a multi-pole switch as in Fig. 7, the cut-outs, Fig. 8, pivoted at their lower ends b<5>, being rocked by links b<1>, b<2> connected between extensions of the metal carrier covers a<1> and an operating-spindle l<3>, which is rotated by moans of an external handle. To prevent spilling of the mercury, ball valves are provided on the overflow chambers, which may be separate or combined, abutments l<8> opening these valves to allow escape of gas in the closed position of the switch, springs a<25> forcing the balls a<24> to close the mercury vessels when the switch is opened, thereby preventing loss of mercury when the switch is in transit.